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WO2024204375A1 - Heat transfer suppressing sheet, method for manufacturing same, and battery module - Google Patents

Heat transfer suppressing sheet, method for manufacturing same, and battery module Download PDF

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Publication number
WO2024204375A1
WO2024204375A1 PCT/JP2024/012288 JP2024012288W WO2024204375A1 WO 2024204375 A1 WO2024204375 A1 WO 2024204375A1 JP 2024012288 W JP2024012288 W JP 2024012288W WO 2024204375 A1 WO2024204375 A1 WO 2024204375A1
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WO
WIPO (PCT)
Prior art keywords
inorganic
sheet
heat transfer
fiber
sewing thread
Prior art date
Application number
PCT/JP2024/012288
Other languages
French (fr)
Japanese (ja)
Inventor
尚紀 女屋
祥啓 古賀
Original Assignee
イビデン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2023053784A external-priority patent/JP2024141910A/en
Priority claimed from JP2023053779A external-priority patent/JP2024141906A/en
Priority claimed from JP2023053780A external-priority patent/JP2024141907A/en
Application filed by イビデン株式会社 filed Critical イビデン株式会社
Publication of WO2024204375A1 publication Critical patent/WO2024204375A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/61—Types of temperature control
    • H01M10/613—Cooling or keeping cold
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/62—Heating or cooling; Temperature control specially adapted for specific applications
    • H01M10/625—Vehicles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/658—Means for temperature control structurally associated with the cells by thermal insulation or shielding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/659—Means for temperature control structurally associated with the cells by heat storage or buffering, e.g. heat capacity or liquid-solid phase changes or transition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a heat transfer suppression sheet and a manufacturing method thereof, as well as a battery module equipped with the heat transfer suppression sheet.
  • lithium-ion secondary batteries have come to be used in electric vehicles and other vehicles in an effort to protect the environment.
  • lithium-ion secondary batteries use an organic electrolyte, if they ignite during thermal runaway, there is a risk of flames being generated and damaging the battery pack.
  • Patent Document 1 proposes a multi-layer heat insulating element in which an intermediate material containing at least one heat-resistant fiber layer or an intermediate layer such as aluminum foil is provided between a first coating layer and a second coating layer.
  • the coating layer and intermediate material are bonded together by adhesion.
  • the adhesive deteriorates with repeated charging and discharging, reducing its adhesive strength, and the adhesive is lost when exposed to high heat from a battery cell that experiences thermal runaway, or in some cases to flames.
  • the adhesive may peel off when subjected to external forces such as bending or twisting.
  • the present invention aims to provide a heat transfer suppression sheet that has a multi-layer structure that not only has excellent heat insulation and flame retardancy, but also maintains its multi-layer structure even when exposed to high heat or flames from a battery cell that has experienced thermal runaway, and a battery module that is equipped with the heat transfer suppression sheet and has excellent safety.
  • a heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with sewing thread having a melting point lower than that of the inorganic fibers of the inorganic sheet.
  • a heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with a sewing thread that has a lower melting point than the inorganic fibers of the inorganic sheet and is thicker than the mesh openings of the inorganic sheet.
  • a preferred embodiment of the present invention relating to the heat transfer suppression sheet relates to the following [5].
  • a heat transfer suppression sheet in which a thermal insulation material and an inorganic sheet are sewn together with an organic or inorganic sewing thread, and a solidified product of the molten sewing thread is present on the surface of the inorganic sheet of the laminate.
  • the heat transfer-suppressing sheet according to [9] wherein the inorganic particles are at least one selected from the group consisting of silica particles, alumina particles, titania particles, zirconia particles, and aluminum hydroxide particles.
  • the sewing thread is at least one of inorganic fibers and organic fibers.
  • the heat transfer-suppressing sheet according to the present invention comprises:
  • the heat transfer suppression sheet of the present invention related to the above "first invention group” is a laminate containing a heat insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the heat insulating material.
  • the laminate is integrated by sewing, and since the sewing thread has a lower melting point than the inorganic fibers of the inorganic sheet, when it is exposed to high heat or flames from a battery cell that has experienced thermal runaway, the stitches of the sewing thread melt, and the molten liquid flows into the inorganic fibers near the surface of the inorganic sheet and inside, and fuses to the inorganic fibers and solidifies, and this solidification acts as a stopper to maintain the laminate structure.
  • the heat transfer suppression sheet of the present invention relating to the above-mentioned "second invention group” is a laminate containing a thermal insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the thermal insulating material.
  • the laminate is integrated by sewing, and since the sewing thread has a lower melting point than the inorganic fibers of the inorganic sheet and is thicker than the mesh openings of the inorganic sheet, when it is exposed to high heat or flames from a battery cell that has experienced thermal runaway, the stitches of the sewing thread melt and solidify, blocking the mesh openings of the inorganic sheet, and this solidified matter functions as a stopper to maintain the laminated structure.
  • the heat transfer suppression sheet of the present invention relating to the above-mentioned "third invention group” is a laminate including a heat insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the heat insulating material.
  • the laminate is integrated by sewing, and by applying high heat above the melting point of the sewing thread to the surface of the inorganic sheet, a solidification of the molten sewing thread is present on the surface of the inorganic sheet, and this solidification acts as a stopper to favorably maintain the laminate structure of the battery cell under normal conditions.
  • the solidification when exposed to high heat or flame from a battery cell that has experienced thermal runaway, the solidification remelts and spreads to the surface of the inorganic sheet and solidifies, thereby maintaining the laminate structure.
  • the battery module of the present invention is highly safe because the heat transfer suppression sheet of the present invention is disposed between the battery case and the storage batteries, so that even if thermal runaway occurs, the spread of fire to the outside can be more reliably prevented.
  • FIG. 1 is an exploded cross-sectional view showing an example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "first invention group.”
  • FIG. 2 is a cross-sectional view that typically shows a cross section of the heat-transfer-suppressing sheet when the inorganic sheet side is subjected to high heat or flame.
  • FIG. 3 is a cross-sectional view showing an embodiment of the battery module of the present invention related to the "first invention group" mentioned above.
  • FIG. 4 is an exploded cross-sectional view showing one example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "second invention group.”
  • FIG. 1 is an exploded cross-sectional view showing an example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "first invention group.”
  • FIG. 2 is a cross-sectional view that typically shows a cross section of the heat-transfer-suppressing
  • FIG. 5 is a cross-sectional view that typically shows a cross section of the heat-transfer-suppressing sheet when the inorganic sheet side is subjected to high heat or flame.
  • FIG. 6 is a photograph, substituted for a drawing, showing the surface of the inorganic sheet after the inorganic sheet side has been exposed to flames.
  • FIG. 7 is a cross-sectional view showing an embodiment of a battery module according to the "second invention group" of the present invention.
  • FIG. 8 is an exploded cross-sectional view that typically shows the configuration of the heat-transfer-suppressing sheet of the present invention related to the "third invention group" before heating.
  • FIG. 9 is a cross-sectional view that shows a schematic example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "third invention group,” in which the inorganic sheet is sewn with a sewing thread that is thicker than the mesh openings.
  • FIG. 10 is a cross-sectional view that shows a schematic diagram of another example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "third invention group,” in which the sheet is sewn with a sewing thread that is thinner than the mesh openings of the inorganic sheet.
  • FIG. 11 is a photograph, substituted for a drawing, showing the surface of a heat-transfer-suppressing sheet produced in an example.
  • FIG. 12 is a cross-sectional view showing an embodiment of a battery module according to the "third invention group" of the present invention.
  • the embodiment for explaining the present invention related to the above-mentioned "first invention group” is referred to as the "first embodiment”
  • the embodiment for explaining the present invention related to the above-mentioned “second invention group” is referred to as the "second embodiment”
  • the embodiment for explaining the present invention related to the above-mentioned “third invention group” is referred to as the "third embodiment”.
  • the heat-transfer-suppressing sheet A1 of this embodiment is formed by sewing together a laminate having a heat insulating material A10 and an inorganic sheet A20 with sewing thread A30.
  • the insulating material A10, inorganic sheet A20, and sewing thread A30 are described in detail below.
  • the heat insulating material A10 has excellent heat insulating performance, and contains inorganic particles and inorganic fibers for holding the inorganic particles.
  • the inorganic fibers may be inorganic fibers normally used in the heat insulating material A10, but it is preferable to have a first inorganic fiber and a second inorganic fiber that are different from each other in at least one property selected from the average fiber diameter, shape, and glass transition point.
  • the average fiber diameter of the first inorganic fiber is larger than that of the second inorganic fiber, the first inorganic fiber is linear or needle-like, and the second inorganic fiber is dendritic or crimped.
  • the first inorganic fiber having a large average fiber diameter (large diameter) has the effect of improving the mechanical strength and shape retention of the thermal insulation material A10. The above effect can be obtained by making one of the two types of inorganic fibers, for example, the first inorganic fiber, larger in diameter than the second inorganic fiber.
  • the inclusion of the first inorganic fiber in the thermal insulation material A10 increases the impact resistance.
  • external impact include pressure due to expansion of the battery cell and wind pressure due to ignition of the battery cell.
  • the first inorganic fiber is linear or needle-shaped.
  • linear or needle-shaped fibers refer to fibers having a degree of crimp, as described below, of less than 10%, preferably 5% or less.
  • the average fiber diameter of the first inorganic fibers is preferably 1 ⁇ m or more, and more preferably 3 ⁇ m or more. If the first inorganic fibers are too thick, moldability and processability may decrease, so the average fiber diameter of the first inorganic fibers is preferably 20 ⁇ m or less, and more preferably 15 ⁇ m or less.
  • first inorganic fibers are too long, moldability and processability may decrease, so it is preferable to set the fiber length to 100 mm or less. Furthermore, if the first inorganic fibers are too short, shape retention and mechanical strength may decrease, so it is preferable to set the fiber length to 0.1 mm or more.
  • the second inorganic fibers which have a small average fiber diameter (thin diameter), have the effect of improving retention and increasing the flexibility of the insulating material A10. Therefore, it is preferable to make the second inorganic fibers smaller in diameter than the first inorganic fibers.
  • the second inorganic fibers are easily deformed and flexible. Therefore, the second inorganic fibers, which are thin, preferably have an average fiber diameter of less than 1 ⁇ m, and more preferably 0.1 ⁇ m or less. However, if they are too thin, they are prone to breakage and their retention ability decreases. Furthermore, a large proportion of the fibers remain entangled in the insulating material A10, which not only reduces retention ability, but also leads to poor moldability and shape retention. Therefore, the average fiber diameter of the second inorganic fibers is preferably 1 nm or more, and more preferably 10 nm or more.
  • the fiber length of the second inorganic fibers is 0.1 mm or less. Furthermore, if the second inorganic fibers are too short, their shape retention and mechanical strength will decrease, so it is preferable that the fiber length be 1 ⁇ m or more.
  • the second inorganic fibers are preferably dendritic or curly.
  • the second inorganic fibers have such a shape, they are well entangled with the inorganic particles, improving the retention capacity.
  • the second inorganic fibers are prevented from sliding and moving, which improves the mechanical strength, particularly against external pressure and impact.
  • dendritic refers to a two-dimensional or three-dimensional branched structure, such as feather-like, tetrapod-like, radial, or three-dimensional mesh-like.
  • the second inorganic fiber When the second inorganic fiber is dendritic, its average fiber diameter can be obtained by measuring the diameters of the trunk and branches at several points using an SEM and calculating the average value.
  • the term "crimped" refers to a structure in which fibers are bent in various directions.
  • a method for quantifying the crimped form it is known to calculate the crimp degree from an electron microscope photograph, and for example, it can be calculated from the following formula.
  • Crimp degree (%) (fiber length ⁇ distance between fiber ends)/(fiber length) ⁇ 100
  • both the fiber length and the distance between the fiber ends are measured values on an electron microscope photograph. That is, the fiber length and the distance between the fiber ends are projected onto a two-dimensional plane, and are shorter than the actual values.
  • the crimp degree of the second inorganic fiber is preferably 10% or more, and more preferably 30% or more. If the crimp degree is small, the retention ability decreases, and it becomes difficult to form entanglements (networks) between the second inorganic fibers and between the first inorganic fibers and the second inorganic fibers.
  • the first inorganic fibers are amorphous fibers
  • the second inorganic fibers are at least one type of fibers selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers.
  • the melting point of crystalline inorganic fibers is usually higher than the glass transition point of amorphous inorganic fibers. Therefore, when exposed to high heat, the surface of the first inorganic fiber softens before the second inorganic fiber, and bonds the inorganic particles. Therefore, by including the first inorganic fiber, the mechanical strength of the insulation material A10 can be improved.
  • the first inorganic fiber is preferably an inorganic fiber having a melting point of less than 700° C., and many amorphous inorganic fibers can be used.
  • fibers containing SiO 2 are preferable, and glass fibers are more preferable because they are inexpensive, easily available, and excellent in handleability.
  • the second inorganic fiber is at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fiber and crystalline fibers. Many crystalline inorganic fibers can be used as the second inorganic fiber.
  • the second inorganic fiber is made of crystalline fiber or has a higher glass transition point than the first inorganic fiber, the second inorganic fiber will not melt or soften when exposed to high heat, even if the first inorganic fiber softens. Therefore, when applied to a battery module, for example, the shape will be maintained even if thermal runaway occurs.
  • the second inorganic fibers do not melt or soften, tiny spaces are maintained between the particles, between the inorganic particles and the fibers, and between each fiber, providing an insulating effect through air.
  • the fibers that can be used include ceramic fibers such as silica fiber, alumina fiber, alumina silicate fiber, zirconia fiber, carbon fiber, soluble fiber, refractory ceramic fiber, aerogel composite material, magnesium silicate fiber, alkaline earth silicate fiber, and potassium titanate fiber; glass fibers, glass fibers such as glass wool, rock wool, and basalt fiber; and natural mineral fibers such as wollastonite as mineral fibers other than those mentioned above.
  • ceramic fibers such as silica fiber, alumina fiber, alumina silicate fiber, zirconia fiber, carbon fiber, soluble fiber, refractory ceramic fiber, aerogel composite material, magnesium silicate fiber, alkaline earth silicate fiber, and potassium titanate fiber
  • glass fibers, glass fibers such as glass wool, rock wool, and basalt fiber
  • natural mineral fibers such as wollastonite as mineral fibers other than those mentioned above.
  • the second inorganic fiber will not melt or soften and will be able to maintain its shape even if thermal runaway occurs in the battery cell, and therefore can be used preferably.
  • the fibers listed above as the second inorganic fiber it is more preferable to use ceramic fibers such as silica fibers, alumina fibers, and alumina silicate fibers, as well as natural mineral fibers, and it is even more preferable to use fibers with a melting point exceeding 1000°C.
  • the second inorganic fiber is amorphous, it can be used as long as it has a higher glass transition point than the first inorganic fiber.
  • glass fiber with a higher glass transition point than the first inorganic fiber may be used as the second inorganic fiber.
  • the various inorganic fibers exemplified above may be used alone or two or more types may be mixed and used.
  • the first inorganic fiber has a lower glass transition point than the second inorganic fiber, and when exposed to high heat, the first inorganic fiber softens first, allowing the first inorganic fiber to bind the inorganic particles.
  • the glass transition point of the second inorganic fiber is preferably 100°C or more higher than the glass transition point of the first inorganic fiber, and more preferably 300°C or more higher.
  • the fiber length of the first inorganic fiber is preferably 100 mm or less, and more preferably 0.1 mm or more.
  • the fiber length of the second inorganic fiber is preferably 0.1 mm or less. The reasons for this are as described above.
  • the first inorganic fibers are amorphous fibers
  • the second inorganic fibers are at least one type of fibers selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers
  • the average fiber diameter of the first inorganic fibers is larger than the average fiber diameter of the second inorganic fibers.
  • the average fiber diameter of the first inorganic fibers is larger than that of the second inorganic fibers. It is also preferable that the thick first inorganic fibers are amorphous fibers, and the thin second inorganic fibers are at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers. This allows the first inorganic fibers to have a low glass transition point and soften quickly, so that they become film-like and harden as the temperature rises.
  • the thin second inorganic fibers are at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers, the thin second inorganic fibers remain in the fiber shape even when the temperature rises, so the structure of the insulating material A10 can be maintained and powder fall can be prevented.
  • the fiber length of the first inorganic fiber is preferably 100 mm or less, and more preferably 0.1 mm or more.
  • the fiber length of the second inorganic fiber is preferably 0.1 mm or less. The reasons for this are as described above.
  • the content of the first inorganic fibers is preferably 3 mass% or more and 30 mass% or less relative to the total mass of the insulation material A10, and the content of the second inorganic fibers is preferably 3 mass% or more and 30 mass% or less relative to the total mass of the insulation material A10.
  • the content of the first inorganic fibers is 5% by mass or more and 15% by mass or less, based on the total mass of the insulating material A10, and it is more preferable that the content of the second inorganic fibers is 5% by mass or more and 15% by mass or less, based on the total mass of the insulating material A10.
  • the inorganic particles When the inorganic particles have an average secondary particle diameter of 0.01 ⁇ m or more, they are easily available and the increase in production costs can be suppressed. When the inorganic particles have an average secondary particle diameter of 200 ⁇ m or less, the desired heat insulating effect can be obtained. Therefore, the average secondary particle diameter of the inorganic particles is preferably 0.01 ⁇ m or more and 200 ⁇ m or less, and more preferably 0.05 ⁇ m or more and 100 ⁇ m or less.
  • the inorganic particles a single inorganic particle may be used, or two or more types of inorganic particles (first inorganic particles and second inorganic particles) may be used in combination. From the viewpoint of the heat transfer suppression effect, it is preferable to use particles made of at least one inorganic material selected from oxide particles, carbide particles, nitride particles, and inorganic hydrate particles as the first inorganic particles and the second inorganic particles, and it is more preferable to use oxide particles.
  • the shape of the first inorganic particles and the second inorganic particles is not particularly limited, but it is preferable to include at least one type selected from nanoparticles, hollow particles, and porous particles. Specifically, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of thermally expandable inorganic materials, particles made of hydrous porous bodies, etc. can also be used.
  • inorganic particles When two or more types of inorganic particles with different heat transfer suppression effects are used in combination, multi-stage cooling is possible, and the heat absorption effect can be expressed over a wider temperature range. Specifically, it is preferable to use a mixture of large-diameter particles and small-diameter particles. For example, when nanoparticles are used as one of the inorganic particles, it is preferable to include inorganic particles made of a metal oxide as the other inorganic particle. Inorganic particles will be described in more detail below, with small-diameter inorganic particles referred to as first inorganic particles and large-diameter inorganic particles referred to as second inorganic particles.
  • Oxide particles As the first inorganic particle, oxide particles are preferred. Oxide particles have a high refractive index and a strong effect of diffusely reflecting light, so that they can suppress radiant heat transfer, especially in high heat regions such as abnormal heat generation. As the oxide particles, at least one type of particle selected from silica particles, titania particles, zirconia particles, zircon particles, barium titanate particles, zinc oxide particles, and alumina particles can be used.
  • silica is a component with high heat insulation properties
  • titania is a component with a high refractive index compared to other metal oxides, and has a high effect of diffusely reflecting light and blocking radiant heat in high heat regions of 500°C or more, so it is most preferable to use silica and titania as oxide particles.
  • the particle size of the oxide particles can affect the effect of reflecting radiant heat, by limiting the average primary particle size to a specified range, even higher thermal insulation can be obtained.
  • the average primary particle size of the oxide particles is 0.001 ⁇ m or more, it is sufficiently larger than the wavelength of light that contributes to heating, and efficiently diffuses light, so that the radiant heat transfer within the heat transfer suppression sheet is suppressed in high heat ranges of 500°C or more, and thermal insulation can be further improved.
  • the average primary particle size of the oxide particles is 50 ⁇ m or less, the number and number of contact points between particles do not increase even when compressed, making it difficult to form a path for conductive heat transfer, and therefore the impact on thermal insulation can be reduced, especially in normal temperature ranges where conductive heat transfer is dominant.
  • the average primary particle size can be determined by observing the particles under a microscope, comparing with a standard scale, and taking the average of any 10 particles.
  • Nanoparticles are preferred as the first inorganic particles, and since nanoparticles have a low density and thus suppress conductive heat transfer, and furthermore, since the voids are finely dispersed, excellent heat insulation properties can be obtained that suppress convective heat transfer. Therefore, it is preferred to use nanoparticles in that the conduction of heat between adjacent nanoparticles can be suppressed during normal use of the battery in the normal temperature range.
  • Nanoparticles refer to particles that are spherical or nearly spherical, with an average primary particle size of less than 1 ⁇ m, on the order of nanometers.
  • nanoparticles with a small average primary particle size are used as the oxide particles, it is possible to suppress an increase in the conductive heat transfer of the insulation material, even if the internal density of the insulation material increases due to expansion caused by thermal runaway of the battery cell. This is thought to be because nanoparticles are prone to creating small gaps between particles due to electrostatic repulsion, and because they have a low bulk density, the particles are packed together to provide a cushioning effect.
  • the material is not particularly limited as long as it is in accordance with the definition of nanoparticles.
  • silica nanoparticles are a material with high heat insulation, and since the contact points between particles are small, the amount of heat conducted by silica nanoparticles is smaller than that when silica particles with a large particle diameter are used.
  • commonly available silica nanoparticles have a bulk density of about 0.1 (g/cm 3 ), for example, even when a large compressive stress is applied to the heat insulating material, the size (area) and number of contact points between silica nanoparticles do not become significantly large, and heat insulation can be maintained. Therefore, it is preferable to use silica nanoparticles as the nanoparticles.
  • silica nanoparticles wet silica, dry silica, aerogel, etc. can be used.
  • the average primary particle diameter of the nanoparticles By limiting the average primary particle diameter of the nanoparticles to a predetermined range, it is possible to obtain even higher thermal insulation.
  • the average primary particle diameter of the nanoparticles by setting the average primary particle diameter of the nanoparticles to 1 nm or more and 100 nm or less, it is possible to suppress convective heat transfer and conductive heat transfer within the insulating material A10, particularly in the temperature range below 500°C, and it is possible to further improve the thermal insulation. Furthermore, even when compressive stress is applied, the gaps remaining between the nanoparticles and the contact points between many particles suppress conductive heat transfer, and it is possible to maintain the thermal insulation.
  • the average primary particle diameter of the nanoparticles is 2 nm or more, and even more preferable that it is 3 nm or more.
  • the average primary particle diameter of the nanoparticles is 50 nm or less, and even more preferable that it is 10 nm or less.
  • inorganic hydrate particles When inorganic hydrate particles receive high heat from a heat source such as a thermal runaway battery cell and the temperature exceeds the temperature at which they start to decompose, they undergo thermal decomposition and release their own water of crystallization to lower the temperature of the heat source and its surroundings, thus exerting the so-called “endothermic effect.” After releasing the water of crystallization, the particles become porous and exert a heat insulating effect due to the countless air holes.
  • a heat source such as a thermal runaway battery cell
  • the temperature exceeds the temperature at which they start to decompose
  • endothermic effect After releasing the water of crystallization, the particles become porous and exert a heat insulating effect due to the countless air holes.
  • inorganic hydrates include aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium hydroxide (Ca(OH) 2 ), zinc hydroxide (Zn(OH) 2 ), iron hydroxide (Fe(OH) 2 ), manganese hydroxide (Mn(OH) 2 ), zirconium hydroxide (Zr(OH) 2 ), and gallium hydroxide (Ga(OH) 3 ).
  • aluminum hydroxide has about 35% water of crystallization, and as shown in the following formula, it thermally decomposes and releases water of crystallization, thereby exerting an endothermic effect. After releasing the water of crystallization, it becomes a porous body, alumina ( Al2O3 ), and functions as a thermal insulator. 2Al(OH) 3 ⁇ Al 2 O 3 +3H 2 O
  • the inorganic particles consist of inorganic hydrates whose thermal decomposition onset temperature is 200°C or higher.
  • the thermal decomposition starting temperatures of the inorganic hydrates listed above are approximately 200°C for aluminum hydroxide, approximately 330°C for magnesium hydroxide, approximately 580°C for calcium hydroxide, approximately 200°C for zinc hydroxide, approximately 350°C for iron hydroxide, approximately 300°C for manganese hydroxide, approximately 300°C for zirconium hydroxide, and approximately 300°C for gallium hydroxide. All of these temperatures roughly overlap with the temperature range of the sudden temperature rise of a battery cell that has experienced thermal runaway, and can efficiently suppress the temperature rise, making these inorganic hydrates preferable.
  • the average secondary particle size of the inorganic hydrate particles is preferably 0.01 ⁇ m or more and 200 ⁇ m or less, and more preferably 0.05 ⁇ m or more and 100 ⁇ m or less.
  • thermally expandable inorganic material particles made of thermally expandable inorganic material
  • examples of the thermally expandable inorganic material include vermiculite, bentonite, mica, and perlite.
  • hydrous porous body particles made of water-containing porous body
  • hydrous porous body include zeolite, kaolinite, montmorillonite, acid clay, diatomaceous earth, wet silica, dry silica, aerogel, mica, and vermiculite.
  • inorganic balloon When inorganic balloons are included, convective or conductive heat transfer within the insulating material A10 can be suppressed in the temperature range below 500° C., thereby further improving the insulating properties of the insulating material A10.
  • inorganic balloons at least one selected from shirasu balloons, silica balloons, fly ash balloons, barite balloons, and glass balloons can be used.
  • the content of inorganic balloons is preferably 60 mass% or less relative to the total mass of the insulating material A10.
  • the average particle size of the inorganic balloons is preferably 1 ⁇ m or more and 100 ⁇ m or less.
  • the second inorganic particles are not particularly limited as long as they are different from the first inorganic particles in terms of material, particle size, etc.
  • the second inorganic particles that can be used include oxide particles, carbide particles, nitride particles, inorganic hydrate particles, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of a thermally expandable inorganic material, particles made of a water-containing porous body, etc., and the details of these are as described above.
  • Nanoparticles have extremely low conductive heat transfer and can maintain excellent heat insulation even when compressive stress is applied to the insulating material A10.
  • Metal oxide particles such as titania are highly effective at blocking radiant heat. Furthermore, when large-diameter inorganic particles and small-diameter inorganic particles are used, the small-diameter inorganic particles enter the gaps between the large-diameter inorganic particles, resulting in a denser structure and improving the heat transfer suppression effect. Therefore, when nanoparticles are used as the first inorganic particles, it is preferable to further include particles made of a metal oxide larger in diameter than the first inorganic particles as the second inorganic particles in the insulating material A10.
  • Metal oxides include silicon oxide, titanium oxide, aluminum oxide, barium titanate, zinc oxide, zircon, zirconium oxide, etc.
  • titanium oxide (titania) has a higher refractive index than other metal oxides, and is highly effective at scattering light and blocking radiant heat in high heat regions of 500°C or higher, making it most preferable to use titania.
  • the average primary particle diameter of the second inorganic particles is 1 ⁇ m or more and 50 ⁇ m or less, radiative heat transfer can be efficiently suppressed in a high heat range of 500°C or more. It is more preferable that the average primary particle diameter of the second inorganic particles is 5 ⁇ m or more and 30 ⁇ m or less, and most preferably 10 ⁇ m or less.
  • the heat insulating material A10 may contain different inorganic fibers in addition to the first inorganic fibers and the second inorganic fibers.
  • the heat insulating material A10 may also contain an organic binder, organic fibers, and inorganic particles.
  • the inorganic fibers can also be bound by a resin binder.
  • a resin binder There are no particular limitations on the resin binder as long as it has a glass transition point lower than that of the organic fibers described below.
  • a resin binder containing at least one selected from styrene-butadiene resin, acrylic resin, silicon-acrylic resin, and styrene resin can be used.
  • the glass transition point of the resin binder is not particularly specified, but is preferably -10°C or higher. If the glass transition point of the resin binder is room temperature or higher, the strength of the insulating material A10 can be further improved when an insulating material having the resin binder is used at room temperature. Therefore, the glass transition point of the resin binder is more preferably 20°C or higher, even more preferably 30°C or higher, even more preferably 50°C or higher, and particularly preferably 60°C or higher.
  • the resin binder content is preferably 0.5% by mass or more, and more preferably 1% by mass or more, relative to the total mass of the insulation material A10. It is also preferable that the content is 20% by mass or less, and more preferably 10% by mass or less.
  • organic fibers may be contained.
  • the organic fibers for example, at least one selected from polyvinyl alcohol (PVA) fibers, polyethylene fibers, nylon fibers, polyurethane fibers, and ethylene-vinyl alcohol copolymer fibers can be used.
  • PVA polyvinyl alcohol
  • Insulating materials can be manufactured using a papermaking method, but since it is difficult to raise the heating temperature above 250°C, it is preferable for the glass transition point of the organic fiber to be 250°C or lower, and more preferably 200°C or lower.
  • the difference between the glass transition point of the resin binder and the glass transition point of the organic fiber is preferably 10°C or more, and more preferably 30°C or more.
  • the difference between the glass transition point of the resin binder and the glass transition point of the organic fibers is preferably 130°C or less, more preferably 120°C or less, even more preferably 100°C or less, even more preferably 80°C or less, and particularly preferably 70°C or less.
  • the difference between the glass transition point of the resin binder and the glass transition point of the at least one type of organic fiber is preferably 10°C or more, more preferably 30°C or more, preferably 130°C or less, more preferably 120°C or less, even more preferably 100°C or less, even more preferably 80°C or less, and particularly preferably 70°C or less.
  • the organic fiber and resin binder contents are appropriately controlled, the organic fiber can fully function as a skeleton, and the resin binder can fully reinforce the skeleton.
  • the organic fiber content is preferably 0.5 mass% or more, and more preferably 1 mass% or more, relative to the total mass of the insulation material A10. It is also preferable that the organic fiber content is 12 mass% or less, and more preferably 8 mass% or less.
  • the insulation material A10 contains multiple organic fibers having a glass transition point higher than the glass transition point of the resin binder, it is preferable that the total amount of these multiple organic fibers is within the range of the organic fiber content.
  • At least one of the organic fibers should have a glass transition point higher than that of the resin binder, but it is more preferable that the other organic fibers include organic fibers in a crystalline state that do not have a glass transition point.
  • crystalline organic fibers that do not have a glass transition point, but because these crystalline organic fibers do not have a softening point, the overall strength of the insulating material A10 can be maintained even when exposed to high heat that would soften the organic fibers that form the skeleton. Furthermore, by including crystalline organic fibers, these organic fibers also act as the skeleton of the insulating material A10 at room temperature. This can therefore improve the flexibility and ease of handling of the insulating material A10.
  • PET polyester
  • the dispersion liquid when performing the papermaking method in the manufacture of the insulating material A10, it is preferable to use water as the dispersion liquid, and it is preferable that the organic fibers have low solubility in water.
  • the "dissolution temperature in water” can be used as an indicator of solubility in water, and the dissolution temperature in water of the organic fibers is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher.
  • the fiber length of the organic fibers is not particularly limited, but from the viewpoint of ensuring moldability and processability, it is preferable that the average fiber length is 10 mm or less. On the other hand, from the viewpoint of making the organic fibers function as a skeleton and ensuring the compressive strength of the insulation material, it is preferable that the average fiber length is 0.5 mm or more.
  • the materials for forming the thermal insulation material A10 are as described above, and a papermaking method can be used to manufacture the thermal insulation material A10. That is, the materials for forming the thermal insulation material A10, such as inorganic particles, inorganic fibers, and other compounding materials, are dispersed in water, and the dispersion is dehydrated, molded, and dried to manufacture the thermal insulation material A10.
  • the materials that make up the insulating material A10 such as inorganic particles, inorganic fibers, and other compounding materials, are put into an appropriate mixer, thoroughly dispersed, and press-molded to produce it.
  • an inorganic fiber cloth or an inorganic nonwoven fabric can be used as the inorganic sheet A20.
  • the inorganic fiber of the inorganic sheet A20 and the inorganic fiber used in the above-mentioned heat insulating material A10 can also be used.
  • silica fiber, alumina fiber, glass fiber, and metal fiber are preferable because they are inexpensive, easy to handle, and have high heat resistance, and at least one of silica cloth and alumina cloth is more preferable because they are easy to sew.
  • Inorganic nonwoven fabric is a paper-made product made from these nonwoven fibers. Considering the need to prevent collisions with debris from a battery cell experiencing thermal runaway, it is preferable for the mesh size to be small.
  • the mesh size of inorganic nonwoven fabric can be determined by placing the inorganic nonwoven fabric under an optical microscope and projecting the image on a monitor, and then reading the size on the image.
  • ⁇ Sewing thread A30> The insulating material A10 and the inorganic sheet A20 are sewn together using sewing thread A30.
  • the sewing thread A30 has a lower melting point than the inorganic fibers of the inorganic sheet A20, and as shown in Fig. 1, the seam A30a is exposed on the surface A20a of the inorganic sheet A20 on the heat source side, such as a battery cell. Since the sewing thread A30 has a lower melting point than the inorganic fibers of the inorganic sheet A20, the seam A30a of the sewing thread A30 melts when exposed to high heat or flame from a heat source, such as a battery cell that has experienced thermal runaway. Note that the covering material A40 on the heat source side (lower side in Fig. 1) is burned away by the high heat or flame.
  • the molten liquid originating from the seams A30a of the sewing thread A30 flows into the vicinity of the surface layer on the surface A20a side of the inorganic sheet A20 and between the inorganic fibers inside, and solidifies while fused to the inorganic fibers.
  • the solidified matter A35 acts as a stopper, maintaining the laminated structure of the insulating material A10 and the inorganic sheet A20.
  • the sewing thread A30 is made thinner than the mesh size of the inorganic sheet A20. That is, in inorganic fiber cloth, the mesh size is almost constant, and a sewing thread A30 thinner than that is used, and in inorganic nonwoven fabric, the mesh size is not constant, but a sewing thread A30 thinner than the minimum mesh size is used. Also, by using a sewing thread A30 thinner than the minimum mesh size, damage to the inorganic sheet A20 is reduced when sewing the insulating material A10 and the inorganic sheet A20 together. There is no lower limit on the thickness of the sewing thread A30, so long as it is within a range in which the sewn state between the insulating material A10 and the inorganic sheet A20 can be maintained.
  • the material for the sewing thread A30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet A20, and is preferably at least one of inorganic and organic fibers. Since the sewing thread A30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that are "self-extinguishing" and do not burn any more after being carbonized, etc.
  • the entire laminate may be surrounded by a covering material A40 as shown in Fig. 1.
  • a covering material A40 various resin films and metal foils can be used, but heat-shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
  • Adhesive layer A50 In order to bond the heat insulating material A10 and the inorganic sheet A20 more firmly, an adhesive layer A50 may be interposed between them as shown in FIG.
  • the adhesive layer A50 evaporates when exposed to high heat or flames from a battery cell that has gone into thermal runaway, and a new air layer A60 is formed.
  • the heat-insulating effect of the air layer A60 is added, and the heat-transfer suppression sheet A1 has better heat-insulating performance.
  • the covering material A40 is attached to the lid of the battery case A120 on the opposite side of the heat source of the heat-transfer suppression sheet A1 (upper side in the figure).
  • the inorganic sheet A20 peels off from the insulating material A10 and sags under its own weight, but the inorganic sheet A20 maintains its sagging state due to the solidified matter A35, and the air layer A60 is formed, improving the heat-insulating performance of the heat-transfer suppression sheet A1 and preventing the spread of fire to the lid of the battery case A120.
  • the battery module A100 contains a plurality of battery cells A110 housed in a battery case A120.
  • the heat-transfer-suppressing sheet A1 is disposed on at least one of the top, side wall, and bottom wall of the battery case A120 (on the entire surfaces of these in the figure) so that the inorganic sheet A20 faces the battery cells A110.
  • the heat-transfer-suppressing sheet A1 may be disposed between the battery cells (storage batteries) A110.
  • the heat-transfer-suppressing sheet B1 of this embodiment is formed by sewing together a laminate having a heat insulating material B10 and an inorganic sheet B20 with sewing thread B30.
  • insulating material B10 and inorganic sheet B20 may be similar to those described in the first embodiment above, and therefore detailed description will be omitted.
  • ⁇ Sewing thread B30> The thermal insulation material B10 and the inorganic sheet B20 are sewn together using the sewing thread B30.
  • the sewing thread B30 has a lower melting point than the inorganic fibers of the inorganic sheet B20 and is made of fibers that are thicker than the mesh size of the inorganic sheet B20. That is, the mesh size of the inorganic fiber cloth is almost constant, and a sewing thread B30 that is thicker than the mesh size is used, while the mesh size of the inorganic nonwoven fabric is not constant, but a sewing thread B30 that is thicker than the maximum mesh size is used.
  • the inorganic fibers of the inorganic sheet B20 are flexible and can be easily deformed, there is no problem with sewing even if the sewing thread B30 is slightly thicker than the mesh size of the inorganic sheet B20. There is no upper limit on the thickness of the sewing thread B30 as long as it can be sewn, but it is preferable that the thickness be such that the fibers constituting the inorganic fiber cloth or inorganic nonwoven fabric are not destroyed.
  • the seams B30a of the sewing thread B30 are exposed on the surface B20a of the inorganic sheet B20 on the heat source side, such as a battery cell. Since the sewing thread B30 has a lower melting point than the inorganic fibers of the inorganic sheet B20, the seams B30a of the sewing thread B30 melt when exposed to high heat or flames from a heat source, such as a battery cell that has undergone thermal runaway. The covering material B40 on the heat source side (lower side in FIG. 4) is burned away by the high heat or flames. In addition, since the sewing thread B30 is thicker than the mesh size of the inorganic sheet B20, when it melts and solidifies, as shown in FIG.
  • the solidified matter B35 becomes a mass (approximately spherical mass) larger than the mesh size of the inorganic sheet B20 and is exposed and scattered on the surface B20a of the inorganic sheet B20.
  • the solidified matter B35 acts as a stopper to maintain the laminated structure of the insulating material B10 and the inorganic sheet B20.
  • the solidified matter B35 is spherical, but if the battery cell, which is the heat source, emits a flame, an explosion may occur along with the high heat, and the molten liquid in the stitch B30a of the sewing thread B30 will be subjected to strong wind pressure, causing the solidified matter B35 to become irregular, such as flattening rather than becoming spherical. Also, the longer the stitch B30a of the sewing thread B30, the greater the amount of molten liquid and the larger the solidified matter B35. Therefore, the size of the solidified matter B35 can be controlled by the length of the stitch B30a of the sewing thread B30.
  • the material of the sewing thread B30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet B20, and is preferably at least one of inorganic fiber and organic fiber. Since the sewing thread B30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that are "self-extinguishing" and do not burn any more after being carbonized, etc.
  • the entire laminate may be surrounded by a covering material B40 as shown in Fig. 4.
  • a covering material B40 various resin films and metal foils can be used, but heat-shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
  • Adhesive layer B50 In order to bond the heat insulating material B10 and the inorganic sheet B20 more firmly, an adhesive layer B50 may be interposed between them as shown in FIG.
  • the adhesive layer B50 when the adhesive layer B50 is exposed to high heat or flames from a battery cell that has gone into thermal runaway, it evaporates, and a new air layer B60 is formed. As a result, the heat-insulating effect of the air layer B60 is added, and the heat-transfer suppression sheet B1 has better heat-insulating performance.
  • the covering material B40 is attached to the lid of the battery case B120 on the opposite side of the heat source of the heat-transfer suppression sheet B1 (upper side in the figure).
  • the inorganic sheet B20 peels off from the insulating material B10 and sags under its own weight, but the inorganic sheet B20 maintains its sagging state due to the solidified matter B35, and the air layer B60 is formed, improving the heat-insulating performance of the heat-transfer suppression sheet B1 and preventing the spread of fire to the lid of the battery case B120.
  • a heat transfer-suppressing sheet B1 was prepared by laminating a heat insulating material B10 containing silica particles and a silica cloth as an inorganic sheet B20, and sewing them together using glass fiber as sewing thread B30. A flame of about 1000° C. was then applied from a burner to the surface of the silica cloth, and the surface of the silica cloth was observed after it was allowed to cool naturally.
  • Figure 6 is a photograph taken of the surface of the silica cloth after it was hit by flame, and it can be seen that there are roughly spherical coagulated masses B35 that originate from the seams of the glass fibers and are larger than the mesh size of the silica cloth.
  • the white area in the upper left of Figure 6 is the area that was hit by flame, and coagulated masses B35 are scattered over almost the entire surface of the area that was hit by flame, with some scattered outside the area that was hit by flame.
  • the battery module B100 contains a plurality of battery cells B110 housed in a battery case B120.
  • the heat-transfer-suppressing sheet B1 is disposed on at least one of the top, side wall, and bottom wall of the battery case B120 (on the entire surfaces of these in the figure) so that the inorganic sheet B20 faces the battery cells B110.
  • the heat-transfer-suppressing sheet B1 may be disposed between the battery cells (storage batteries) B110.
  • the heat transfer-inhibiting sheet C1 of this embodiment is formed by sewing together a laminate having an insulating material C10 and an inorganic sheet C20 with a sewing thread C30, and further, as shown in Figure 9, a solidified material C35 of the molten sewing thread C30 is exposed from the surface C20a of the inorganic sheet C20, or, as shown in Figure 10, the molten sewing thread C30 has flowed into the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20 or between the inorganic fibers inside, and has solidified while remaining fused to the inorganic fibers, forming a solidified material C35.
  • the "surface portion of the inorganic sheet” in the present invention includes the surface C20a of the inorganic sheet C20 itself, and the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20 (specifically, the range up to half the thickness of the inorganic sheet C20 when viewed from the surface C20a side of the inorganic sheet C20, preferably the range up to 1/3 the thickness of the inorganic sheet C20 when viewed from the surface C20a side of the inorganic sheet C20).
  • insulating material C10 and inorganic sheet C20 may be similar to those described in the first embodiment above, and therefore detailed description will be omitted.
  • the heat insulating material C10 and the inorganic sheet C20 are sewn together using a sewing thread C30.
  • the sewing thread C30 uses fibers having a lower melting point than the inorganic fibers of the inorganic sheet C20.
  • the material of the sewing thread C30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet C20, and is preferably at least one of inorganic fiber and organic fiber. Since the sewing thread C30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that have "self-extinguishing properties" that do not burn any more after being carbonized, etc.
  • the thickness of the sewing thread C30 can be selected so long as it does not interfere with sewing.
  • the heat transfer suppression sheet C1 is obtained by applying high heat above the melting point of the sewing thread C30 to the surface of the inorganic sheet C20 of the laminate in which the insulating material C10 and the inorganic sheet C20 are sewn together with the sewing thread C30.
  • the solidified matter C35 is spherical, but it may be of an indefinite shape.
  • the molten liquid originating from the stitches C30a of the sewing thread C30 flows between the inorganic fibers near the surface layer on the surface C20a side of the inorganic sheet C20, and solidifies while fused to the inorganic fibers, forming a solidified mass C35 as shown by the wavy line in the figure.
  • the solidified material C35 acts as a stopper to maintain the laminated structure of the insulating material C10 and the inorganic sheet C20.
  • the mesh size is almost constant, and a sewing thread C30 thicker than that is used. Also, in the case of inorganic nonwoven fabric, the mesh size is not constant, but a sewing thread C30 thicker than the maximum mesh size is used. Since the inorganic fibers in inorganic fiber cloth and inorganic nonwoven fabric are flexible and can be easily deformed, there is no problem with sewing even if the sewing thread C30 is thicker than the mesh size of the inorganic fiber cloth or inorganic nonwoven fabric. There is no upper limit on the thickness of the sewing thread C30, so long as it is within the range in which the insulating material C10 and the inorganic sheet C20 can be sewn together.
  • a sewing thread C30 finer than the minimum mesh size is used for the inorganic nonwoven fabric. Furthermore, by using a sewing thread C30 finer than the minimum mesh size, damage to the inorganic sheet C20 is reduced when sewing the insulating material C10 and the inorganic sheet C20 together. There is no lower limit to the thickness of the sewing thread C30, so long as it is within a range in which the insulating material C10 and the inorganic sheet C20 can be sewn together.
  • the mesh size of the inorganic nonwoven fabric can be read from the image by placing the inorganic nonwoven fabric under an optical microscope and projecting the image on a monitor.
  • the solidified matter C35 remelts and flows over a wider area on the surface of the inorganic sheet C20 (i.e., the surface C20a of the inorganic sheet C20 itself and in the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20), where it solidifies. This further enhances its function as a stopper.
  • the entire laminate may be surrounded by a covering material C40 as shown in Fig. 8.
  • a covering material C40 various resin films and metal foils can be used, but heat shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
  • Adhesive layer C50 In order to bond the heat insulating material C10 and the inorganic sheet C20 more firmly, an adhesive layer C50 may be interposed between them as shown in FIG.
  • the adhesive layer C50 volatilizes when exposed to high heat, and a new air layer C60 is formed. As a result, the heat-insulating effect of the air layer C60 is added, and the heat-transfer-suppressing sheet C1 has superior heat-insulating performance.
  • a burner flame may be applied to the surface C20a of the inorganic sheet C20, or a hot plate heated to the above-mentioned temperature may be pressed against the surface C20a of the inorganic sheet C20. Then, the molten liquid derived from the seam C30a may be hardened by natural cooling.
  • a heat transfer-suppressing sheet C1 was prepared by laminating a heat insulating material C10 containing silica particles and a silica cloth as an inorganic sheet C20, and sewing them together using glass fiber as sewing thread C30. A flame of about 1000° C. was then applied from a burner to the surface of the silica cloth, and the surface of the silica cloth was observed after natural cooling.
  • Figure 11 is a photograph taken of the surface of the silica cloth after it was hit by flame, and it can be seen that there are spherical coagulations C35 that originate from the seams of the glass fibers and are larger than the mesh size of the silica cloth.
  • the white area in the upper left of Figure 11 is the part that was hit by flame, and coagulations C35 are scattered over almost the entire surface of the part that was hit by flame, with some scattered outside the part that was hit by flame.
  • the battery module C100 contains a plurality of battery cells C110 housed in a battery case C120.
  • the heat transfer suppressing sheet C1 is disposed on at least one of the top, side wall, and bottom wall of the battery case C120 (on the entire surfaces of these in the figure) so that the inorganic sheet C20 faces the battery cells C110.
  • the heat transfer suppressing sheet C1 may be disposed between the battery cells (storage batteries) C110.

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Abstract

Provided are: a heat transfer suppressing sheet which has a multilayer structure and has a more outstanding heat insulating effect and flame retarding effect, in addition to which the multilayer structure can be maintained even when exposed to a high heat or a flame from a battery cell that has undergone thermal runaway; and a battery module that is provided with the heat transfer suppressing sheet and that is extremely safe. In a heat transfer suppressing sheet (A1), a laminated body including a heat insulating material (A10) and an inorganic sheet (A20) is sewn together using a sewing thread (A30) that has a melting point lower than that of inorganic fibers of the inorganic sheet (A20), and that is preferably thinner than openings of the inorganic sheet (A20), and a battery module (A100) accommodates storage batteries (A110) in a battery case (A120), the heat transfer suppressing sheet (A1) being disposed between the storage batteries (A110), and/or the top of the battery case (A120), and/or a side wall of the battery case (A120), and/or the bottom wall of the battery case (A120).

Description

熱伝達抑制シート及びその製造方法、並びに電池モジュールHeat transfer suppression sheet, manufacturing method thereof, and battery module
　本発明は、熱伝達抑制シート及びその製造方法、並びに熱伝達抑制シートを備える電池モジュールに関する。 The present invention relates to a heat transfer suppression sheet and a manufacturing method thereof, as well as a battery module equipped with the heat transfer suppression sheet.
　近年、環境保全のために、電気自動車などにリチウムイオン２次電池が用いられている。しかし、リチウムイオン２次電池は、有機電解液を使用しているために、熱暴走時に着火すると火炎が発生してバッテリーパックを損傷するおそれがある。 In recent years, lithium-ion secondary batteries have come to be used in electric vehicles and other vehicles in an effort to protect the environment. However, because lithium-ion secondary batteries use an organic electrolyte, if they ignite during thermal runaway, there is a risk of flames being generated and damaging the battery pack.
　その対策として、無機繊維や無機粒子などを含む断熱材や、複数種の層を積層して断熱効果や防炎効果を高めた熱伝達抑制シートが使用されている。例えば特許文献１では、第１の被覆層と第２の被覆層との間に、少なくとも１つの耐熱繊維層や、アルミニウム箔などの中間層を含む中間材を設けて積層した多層断熱要素を提案している。 As a countermeasure, heat insulating materials containing inorganic fibers or inorganic particles, or heat transfer suppression sheets that have multiple layers stacked together to enhance their insulating and fireproofing effects, are being used. For example, Patent Document 1 proposes a multi-layer heat insulating element in which an intermediate material containing at least one heat-resistant fiber layer or an intermediate layer such as aluminum foil is provided between a first coating layer and a second coating layer.
日本国特表２０２１－５０７４８３号公報Japan Special Table No. 2021-507483
　しかしながら、特許文献１の多層断熱要素では、被覆層及び中間材は接着により結合されている。そのため、繰り返し行われる充放電に伴って接着剤が劣化して接着力が低下したり、熱暴走を起こした電池セルからの高熱や、場合によっては火炎を受けて接着剤が消失する。また、曲げや捻じれなどの外力を受けた際に、接着剤が剥離するおそれもある。 However, in the multilayer insulation element of Patent Document 1, the coating layer and intermediate material are bonded together by adhesion. As a result, the adhesive deteriorates with repeated charging and discharging, reducing its adhesive strength, and the adhesive is lost when exposed to high heat from a battery cell that experiences thermal runaway, or in some cases to flames. There is also a risk that the adhesive may peel off when subjected to external forces such as bending or twisting.
　そこで本発明は、多層構造にして断熱効果や防炎効果により優れることに加えて、熱暴走を起こした電池セルからの高熱や火炎を受けた場合にも多層構造を維持できる熱伝達抑制シート、及び前記熱伝達抑制シートを備え、安全性に優れた電池モジュールを提供することを目的とする。 The present invention aims to provide a heat transfer suppression sheet that has a multi-layer structure that not only has excellent heat insulation and flame retardancy, but also maintains its multi-layer structure even when exposed to high heat or flames from a battery cell that has experienced thermal runaway, and a battery module that is equipped with the heat transfer suppression sheet and has excellent safety.
　本発明の上記目的は、熱伝達抑制シートに係る下記［１］の構成により達成される。 The above object of the present invention is achieved by the following configuration [1] relating to the heat transfer suppression sheet.
［１］　断熱材と、無機シートとを含む積層体が、前記無機シートの無機繊維よりも融点が低い縫糸で縫合されている、熱伝達抑制シート。 [1] A heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with sewing thread having a melting point lower than that of the inorganic fibers of the inorganic sheet.
　また、熱伝達抑制シートに係る本発明の好ましい実施形態は、以下の［２］～［３］に関する。 Furthermore, preferred embodiments of the present invention relating to the heat transfer suppression sheet relate to the following [2] to [3].
［２］　前記縫糸は、前記無機シートの目開きよりも細いことを特徴とする［１］に記載の熱伝達抑制シート。
［３］　前記無機シートが無機繊維クロス又は無機不織布であり、かつ、前記無機シートが前記無機繊維クロスの場合には、前記縫糸が前記無機繊維クロスの目開きよりも細く、また、前記無機シートが前記無機不織布の場合には、前記無機不織布の最小目開きよりも細いことを特徴とする［２］に記載の熱伝達抑制シート。 [2] The heat transfer-suppressing sheet according to [1], wherein the sewing thread is thinner than the mesh opening of the inorganic sheet.
[3] The heat transfer-suppressing sheet according to [2], wherein the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric, and, when the inorganic sheet is the inorganic fiber cloth, the sewing thread is finer than the mesh size of the inorganic fiber cloth, and, when the inorganic sheet is the inorganic nonwoven fabric, the sewing thread is finer than the minimum mesh size of the inorganic nonwoven fabric.
　なお、本明細書において上記［１］～［３］に係る発明を「第１発明群」と称する。 In this specification, the inventions relating to [1] to [3] above are referred to as the "first invention group."
　また、本発明の上記目的は、熱伝達抑制シートに係る下記［４］の構成により達成される。 The above object of the present invention is also achieved by the following configuration [4] relating to the heat transfer suppression sheet.
［４］　断熱材と、無機シートとを含む積層体が、前記無機シートの無機繊維よりも融点が低く、前記無機シートの目開きよりも太い縫糸で縫合されている、熱伝達抑制シート。 [4] A heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with a sewing thread that has a lower melting point than the inorganic fibers of the inorganic sheet and is thicker than the mesh openings of the inorganic sheet.
　また、熱伝達抑制シートに係る本発明の好ましい実施形態は、以下の［５］に関する。 　Furthermore, a preferred embodiment of the present invention relating to the heat transfer suppression sheet relates to the following [5].
［５］　前記無機シートが無機繊維クロス又は無機不織布であり、かつ、前記無機シートが前記無機繊維クロスの場合には、前記縫糸が前記無機繊維クロスの目開きよりも太く、また、前記無機シートが前記無機不織布の場合には、前記無機不織布の最大目開きよりも太いことを特徴とする［４］に記載の熱伝達抑制シート。 [5] The heat transfer suppression sheet according to [4], characterized in that the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric, and in the case where the inorganic sheet is the inorganic fiber cloth, the sewing thread is thicker than the mesh size of the inorganic fiber cloth, and in the case where the inorganic sheet is the inorganic nonwoven fabric, the sewing thread is thicker than the maximum mesh size of the inorganic nonwoven fabric.
　なお、本明細書において上記［４］～［５］に係る発明を「第２発明群」と称する。 In this specification, the inventions relating to [4] and [5] above are referred to as the "second invention group."
　また、本発明の上記目的は、熱伝達抑制シートに係る下記［６］の構成により達成される。 The above object of the present invention is also achieved by the following configuration [6] relating to the heat transfer suppression sheet.
［６］　断熱材と、無機シートとが、有機質又は無機質の縫糸にて縫合された積層体の前記無機シートの表面部に、前記縫糸の溶融物の凝固物が存在する、熱伝達抑制シート。 [6] A heat transfer suppression sheet in which a thermal insulation material and an inorganic sheet are sewn together with an organic or inorganic sewing thread, and a solidified product of the molten sewing thread is present on the surface of the inorganic sheet of the laminate.
　また、熱伝達抑制シートに係る本発明の好ましい実施形態は、以下の［７］～［８］に関する。 Furthermore, preferred embodiments of the present invention relating to the heat transfer suppression sheet relate to the following [7] to [8].
［７］　前記無機シートは、無機繊維クロス又は無機不織布であることを特徴とする［６］に記載の熱伝達抑制シート。
［８］　前記凝固物は、前記無機シートの表面部に点在していることを特徴とする［６］に記載の熱伝達抑制シート。 [7] The heat transfer-suppressing sheet according to [6], wherein the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric.
[8] The heat transfer-suppressing sheet according to [6], wherein the coagulated matter is scattered on a surface portion of the inorganic sheet.
　なお、本明細書において上記［６］～［８］に係る発明を「第３発明群」と称する。 In this specification, the inventions relating to [6] to [8] above are referred to as the "third invention group."
　また、熱伝達抑制シートに係る本発明の好ましい実施形態は、以下の［９］～［１４］に関する。 Furthermore, preferred embodiments of the present invention relating to the heat transfer suppression sheet relate to the following [9] to [14].
［９］　前記断熱材は、無機粒子を含むことを特徴とする［１］～［８］のいずれか１つに記載の熱伝達抑制シート。
［１０］　前記無機粒子は、シリカ粒子、アルミナ粒子、チタニア粒子、ジルコニア粒子及び水酸化アルミニウム粒子のうち少なくとも一種から選ばれることを特徴とする［９］に記載の熱伝達抑制シート。
［１１］　前記縫糸は、無機繊維及び有機繊維のうち少なくとも一種であることを特徴とする［１］～［１０］のいずれか１つに記載の熱伝達抑制シート。
［１２］　前記縫糸は、ガラス繊維、シリカ繊維、チタン酸カリウム繊維、ケイ酸カルシウム繊維、アラミド繊維及びナイロン繊維のうち少なくとも一種から選ばれることを特徴とする［１１］に記載の熱伝達抑制シート。
［１３］　前記無機シートは、シリカクロス及びアルミナクロスのうち少なくとも一種であることを特徴とする［１］～［１２］のいずれか１つに記載の熱伝達抑制シート。
［１４］　前記断熱材と、前記無機シートとが、接着剤層を介して接合されていることを特徴とする［１］～［１３］のいずれか１つに記載の熱伝達抑制シート。 [9] The heat-transfer-suppressing sheet according to any one of [1] to [8], wherein the heat-insulating material contains inorganic particles.
[10] The heat transfer-suppressing sheet according to [9], wherein the inorganic particles are at least one selected from the group consisting of silica particles, alumina particles, titania particles, zirconia particles, and aluminum hydroxide particles.
[11] The heat-transfer-suppressing sheet according to any one of [1] to [10], wherein the sewing thread is at least one of inorganic fibers and organic fibers.
[12] The heat-transfer-suppressing sheet according to [11], wherein the sewing thread is selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber.
[13] The heat-transfer-suppressing sheet according to any one of [1] to [12], wherein the inorganic sheet is at least one of a silica cloth and an alumina cloth.
[14] The heat transfer-suppressing sheet according to any one of [1] to [13], wherein the heat insulating material and the inorganic sheet are bonded to each other via an adhesive layer.
　また、本発明の上記目的は、熱伝達抑制シートの製造方法に係る下記［１５］の構成により達成される。 The above object of the present invention is also achieved by the following configuration [15] relating to the method for producing a heat transfer suppression sheet.
［１５］　［６］～［８］のいずれか１つに記載の熱伝達抑制シートの製造方法であって、
　断熱材と、無機シートとを含む積層体を、有機質又は無機質の縫糸にて縫合する工程と、
　縫合された前記積層体の前記無機シートの表面に、前記縫糸の融点以上の高熱を作用させて前記縫糸を溶融する工程と、
　前記縫糸の溶融物を硬化させる工程と、
を有する、熱伝達抑制シートの製造方法。 [15] A method for producing a heat transfer-suppressing sheet according to any one of [6] to [8], comprising the steps of:
A step of sewing a laminate including a thermal insulating material and an inorganic sheet with an organic or inorganic sewing thread;
a step of applying high heat equal to or higher than the melting point of the sewing thread to a surface of the inorganic sheet of the sewn laminate to melt the sewing thread;
hardening the melt of the sewing thread;
The heat transfer-suppressing sheet according to the present invention comprises:
　また、本発明の上記目的は、電池モジュールに係る下記［１６］の構成により達成される。 The above object of the present invention is also achieved by the following configuration [16] relating to the battery module.
［１６］　蓄電池を電池ケースに収容し、かつ、前記電池ケースの天蓋、側壁、底壁、並びに前記蓄電池の間の少なくとも１つに、［１］～［１４］のいずれか１つに記載の熱伝達抑制シートを配設した、電池モジュール。 [16] A battery module in which a storage battery is housed in a battery case, and a heat transfer suppression sheet described in any one of [1] to [14] is disposed on at least one of the top, side walls, and bottom walls of the battery case, and between the storage batteries.
　上記「第１発明群」に係る本発明の熱伝達抑制シートは、断熱材と無機シートとを含む積層体であり、無機シートが、熱暴走を起こした電池セルからの金属片等の飛散物が断熱材に直接衝突することを防止する。また、積層体を縫合により一体化しているが、縫糸は無機シートの無機繊維よりも融点が低いため、熱暴走を起こした電池セルからの高熱や火炎を受けた際に、縫糸の縫目が溶融し、その融液が無機シートの表層近傍や内部の無機繊維間に流入し、無機繊維に融着して凝固し、この凝固物がストッパーとして機能して積層構造を維持する。 The heat transfer suppression sheet of the present invention related to the above "first invention group" is a laminate containing a heat insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the heat insulating material. In addition, the laminate is integrated by sewing, and since the sewing thread has a lower melting point than the inorganic fibers of the inorganic sheet, when it is exposed to high heat or flames from a battery cell that has experienced thermal runaway, the stitches of the sewing thread melt, and the molten liquid flows into the inorganic fibers near the surface of the inorganic sheet and inside, and fuses to the inorganic fibers and solidifies, and this solidification acts as a stopper to maintain the laminate structure.
　上記「第２発明群」に係る本発明の熱伝達抑制シートは、断熱材と無機シートとを含む積層体であり、無機シートが、熱暴走を起こした電池セルからの金属片等の飛散物が断熱材に直接衝突することを防止する。また、積層体を縫合により一体化しているが、縫糸は無機シートの無機繊維よりも融点が低く、無機シートの目開きよりも太いため、熱暴走を起こした電池セルからの高熱や火炎を受けた際に、縫糸の縫目が溶融して無機シートの目開きを塞いで凝固し、この凝固物がストッパーとして機能して積層構造を維持する。 The heat transfer suppression sheet of the present invention relating to the above-mentioned "second invention group" is a laminate containing a thermal insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the thermal insulating material. In addition, the laminate is integrated by sewing, and since the sewing thread has a lower melting point than the inorganic fibers of the inorganic sheet and is thicker than the mesh openings of the inorganic sheet, when it is exposed to high heat or flames from a battery cell that has experienced thermal runaway, the stitches of the sewing thread melt and solidify, blocking the mesh openings of the inorganic sheet, and this solidified matter functions as a stopper to maintain the laminated structure.
　上記「第３発明群」に係る本発明の熱伝達抑制シートは、断熱材と無機シートとを含む積層体であり、無機シートが、熱暴走を起こした電池セルからの金属片等の飛散物が断熱材に直接衝突することを防止する。また、積層体を縫合により一体化しているとともに、無機シートの表面に縫糸の融点以上の高熱を作用させることにより、縫糸の溶融物の凝固物が無機シートの表面部に存在しており、この凝固物がストッパーとして機能して電池セルの通常時における積層構造を良好に維持する。更には、熱暴走を起こした電池セルからの高熱や火炎を受けた際に、凝固物が再溶融して無機シートの表面部に広がり、凝固するため、積層構造を維持する。 The heat transfer suppression sheet of the present invention relating to the above-mentioned "third invention group" is a laminate including a heat insulating material and an inorganic sheet, and the inorganic sheet prevents flying debris such as metal pieces from a battery cell that has experienced thermal runaway from directly colliding with the heat insulating material. In addition, the laminate is integrated by sewing, and by applying high heat above the melting point of the sewing thread to the surface of the inorganic sheet, a solidification of the molten sewing thread is present on the surface of the inorganic sheet, and this solidification acts as a stopper to favorably maintain the laminate structure of the battery cell under normal conditions. Furthermore, when exposed to high heat or flame from a battery cell that has experienced thermal runaway, the solidification remelts and spreads to the surface of the inorganic sheet and solidifies, thereby maintaining the laminate structure.
　また、本発明の電池モジュールは、本発明の熱伝達抑制シートが電池ケースや蓄電池間に配設されているため、熱暴走が起こったとしても、外部への延焼をより確実に防ぐことができ、安全性が高い。 In addition, the battery module of the present invention is highly safe because the heat transfer suppression sheet of the present invention is disposed between the battery case and the storage batteries, so that even if thermal runaway occurs, the spread of fire to the outside can be more reliably prevented.
図１は、上記「第１発明群」に係る本発明の熱伝達抑制シートの一例を示す分解断面図である。FIG. 1 is an exploded cross-sectional view showing an example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "first invention group." 図２は、無機シート側が高熱又は火炎を受けた時の熱伝達抑制シートの断面を模式的に示す断面図である。FIG. 2 is a cross-sectional view that typically shows a cross section of the heat-transfer-suppressing sheet when the inorganic sheet side is subjected to high heat or flame. 図３は、上記「第１発明群」に係る本発明の電池モジュールの実施の形態を示す断面図である。FIG. 3 is a cross-sectional view showing an embodiment of the battery module of the present invention related to the "first invention group" mentioned above. 図４は、上記「第２発明群」に係る本発明の熱伝達抑制シートの一例を示す分解断面図である。FIG. 4 is an exploded cross-sectional view showing one example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "second invention group." 図５は、無機シート側が高熱又は火炎を受けた時の熱伝達抑制シートの断面を模式的に示す断面図である。FIG. 5 is a cross-sectional view that typically shows a cross section of the heat-transfer-suppressing sheet when the inorganic sheet side is subjected to high heat or flame. 図６は、無機シート側が火炎を受けた後の無機シートの表面を撮影した図面代用写真である。FIG. 6 is a photograph, substituted for a drawing, showing the surface of the inorganic sheet after the inorganic sheet side has been exposed to flames. 図７は、上記「第２発明群」に係る本発明の電池モジュールの実施の形態を示す断面図である。FIG. 7 is a cross-sectional view showing an embodiment of a battery module according to the "second invention group" of the present invention. 図８は、上記「第３発明群」に係る本発明の熱伝達抑制シートの加熱前の構成を模式的に示す分解断面図である。FIG. 8 is an exploded cross-sectional view that typically shows the configuration of the heat-transfer-suppressing sheet of the present invention related to the "third invention group" before heating. 図９は、上記「第３発明群」に係る本発明の熱伝達抑制シートの一例を模式的に示す断面図であり、無機シートの目開きよりも太い縫糸で縫合した場合を示している。FIG. 9 is a cross-sectional view that shows a schematic example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "third invention group," in which the inorganic sheet is sewn with a sewing thread that is thicker than the mesh openings. 図１０は、上記「第３発明群」に係る本発明の熱伝達抑制シートの他の例を模式的に示す断面図であり、無機シートの目開きよりも細い縫糸で縫合した場合を示している。FIG. 10 is a cross-sectional view that shows a schematic diagram of another example of the heat-transfer-suppressing sheet of the present invention related to the above-mentioned "third invention group," in which the sheet is sewn with a sewing thread that is thinner than the mesh openings of the inorganic sheet. 図１１は、実施例で作製した熱伝達抑制シートの表面を撮影した図面代用写真である。FIG. 11 is a photograph, substituted for a drawing, showing the surface of a heat-transfer-suppressing sheet produced in an example. 図１２は、上記「第３発明群」に係る本発明の電池モジュールの実施の形態を示す断面図である。FIG. 12 is a cross-sectional view showing an embodiment of a battery module according to the "third invention group" of the present invention.
　以下、本発明の実施形態に関して図面を参照して詳細に説明する。なお、本発明は、以下で説明する実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において、任意に変更して実施することができる。 Below, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below, and can be modified as desired without departing from the gist of the present invention.
　また、以下に示す実施形態においては、上記「第１発明群」に係る本発明を説明するための実施形態を「第１実施形態」とし、上記「第２発明群」に係る本発明を説明するための実施形態を「第２実施形態」とし、上記「第３発明群」に係る本発明を説明するための実施形態を「第３実施形態」とする。 In addition, in the embodiments described below, the embodiment for explaining the present invention related to the above-mentioned "first invention group" is referred to as the "first embodiment", the embodiment for explaining the present invention related to the above-mentioned "second invention group" is referred to as the "second embodiment", and the embodiment for explaining the present invention related to the above-mentioned "third invention group" is referred to as the "third embodiment".
　まず、上記「第１発明群」に係る「第１実施形態」について説明する。 First, we will explain the "first embodiment" related to the above-mentioned "first invention group."
［熱伝達抑制シート］
　図１に分解断面図で示すように、本実施形態の熱伝達抑制シートＡ１は、断熱材Ａ１０と、無機シートＡ２０とを有する積層体を、縫糸Ａ３０で縫合して一体化したものである。 [Heat transfer suppression sheet]
As shown in the exploded cross-sectional view of FIG. 1, the heat-transfer-suppressing sheet A1 of this embodiment is formed by sewing together a laminate having a heat insulating material A10 and an inorganic sheet A20 with sewing thread A30.
　以下に、断熱材Ａ１０、無機シートＡ２０及び縫糸Ａ３０について詳述する。 The insulating material A10, inorganic sheet A20, and sewing thread A30 are described in detail below.
＜断熱材Ａ１０＞
（無機繊維）
　断熱材Ａ１０は、断熱性能に優れることから、無機粒子と、無機粒子を保持するための無機繊維とを含む。無機繊維は、断熱材Ａ１０に通常使用される無機繊維を用いることができるが、平均繊維径、形状及びガラス転移点から選択された少なくとも１種の性状が互いに異なる第１の無機繊維及び第２の無機繊維を有することが好ましい。性状が互いに異なる２種の無機繊維を含有することにより、断熱材Ａ１０の機械的強度、並びに無機粒子の保持性を向上させることができる。 <Thermal insulation material A10>
(Inorganic fiber)
The heat insulating material A10 has excellent heat insulating performance, and contains inorganic particles and inorganic fibers for holding the inorganic particles. The inorganic fibers may be inorganic fibers normally used in the heat insulating material A10, but it is preferable to have a first inorganic fiber and a second inorganic fiber that are different from each other in at least one property selected from the average fiber diameter, shape, and glass transition point. By containing two types of inorganic fibers with different properties, the mechanical strength of the heat insulating material A10 and the retention of the inorganic particles can be improved.
（平均繊維径及び繊維形状が異なる２種の無機繊維）
　２種の無機繊維を含有する場合に、第１の無機繊維の平均繊維径が、第２の無機繊維の平均繊維径よりも大きく、第１の無機繊維が線状又は針状であり、第２の無機繊維が樹枝状又は縮れ状であることが好ましい。平均繊維径が大きい（太径の）第１の無機繊維は、断熱材Ａ１０の機械的強度や形状保持性を向上させる効果を有する。２種の無機繊維のうち一方、例えば、第１の無機繊維を第２の無機繊維よりも太径にすることにより、上記効果を得ることができる。熱伝達抑制シートＡ１には、外部からの衝撃が作用することがあるため、断熱材Ａ１０に第１の無機繊維が含まれることにより、耐衝撃性が高まる。外部からの衝撃としては、例えば電池セルの膨張による押圧力や、電池セルの発火による風圧などである。 (Two types of inorganic fibers with different average fiber diameters and fiber shapes)
When two types of inorganic fibers are contained, it is preferable that the average fiber diameter of the first inorganic fiber is larger than that of the second inorganic fiber, the first inorganic fiber is linear or needle-like, and the second inorganic fiber is dendritic or crimped. The first inorganic fiber having a large average fiber diameter (large diameter) has the effect of improving the mechanical strength and shape retention of the thermal insulation material A10. The above effect can be obtained by making one of the two types of inorganic fibers, for example, the first inorganic fiber, larger in diameter than the second inorganic fiber. Since the heat transfer suppressing sheet A1 may be subjected to an external impact, the inclusion of the first inorganic fiber in the thermal insulation material A10 increases the impact resistance. Examples of external impact include pressure due to expansion of the battery cell and wind pressure due to ignition of the battery cell.
　また、断熱材Ａ１０の機械的強度や形状保持性を向上させるためには、第１の無機繊維が線状又は針状であることが特に好ましい。なお、線状又は針状の繊維とは、後述の捲縮度が例えば１０％未満、好ましくは５％以下である繊維をいう。 In order to improve the mechanical strength and shape retention of the insulating material A10, it is particularly preferable that the first inorganic fiber is linear or needle-shaped. Note that linear or needle-shaped fibers refer to fibers having a degree of crimp, as described below, of less than 10%, preferably 5% or less.
　より具体的には、第１の無機繊維の平均繊維径は１μｍ以上であることが好ましく、３μｍ以上であることがより好ましい。第１の無機繊維が太すぎると、成形性や加工性が低下するおそれがあるため、第１の無機繊維の平均繊維径は２０μｍ以下であることが好ましく、１５μｍ以下であることがより好ましい。 More specifically, the average fiber diameter of the first inorganic fibers is preferably 1 μm or more, and more preferably 3 μm or more. If the first inorganic fibers are too thick, moldability and processability may decrease, so the average fiber diameter of the first inorganic fibers is preferably 20 μm or less, and more preferably 15 μm or less.
　なお、第１の無機繊維は長すぎても成形性や加工性が低下するおそれがあるため、繊維長を１００ｍｍ以下とすることが好ましい。さらに、第１の無機繊維は短すぎても形状保持性や機械的強度が低下するため、繊維長を０．１ｍｍ以上とすることが好ましい。 If the first inorganic fibers are too long, moldability and processability may decrease, so it is preferable to set the fiber length to 100 mm or less. Furthermore, if the first inorganic fibers are too short, shape retention and mechanical strength may decrease, so it is preferable to set the fiber length to 0.1 mm or more.
　一方、平均繊維径が細い（細径の）第２の無機繊維は、保持性を向上させるとともに、断熱材Ａ１０の柔軟性を高める効果を有する。したがって、第２の無機繊維を第１の無機繊維よりも細径にすることが好ましい。 On the other hand, the second inorganic fibers, which have a small average fiber diameter (thin diameter), have the effect of improving retention and increasing the flexibility of the insulating material A10. Therefore, it is preferable to make the second inorganic fibers smaller in diameter than the first inorganic fibers.
　より具体的に、保持性を向上させるためには、第２の無機繊維は変形が容易で、柔軟性を有することが好ましい。したがって、細径である第２の無機繊維は、平均繊維径が１μｍ未満であることが好ましく、０．１μｍ以下であることがより好ましい。ただし、細すぎると破断しやすく、保持能力が低下する。また、繊維が絡み合ったままで断熱材Ａ１０中に存在する割合が多くなり、保持能力の低下に加えて、成形性や形状保持性にも劣るようになる。そのため、第２の無機繊維の平均繊維径は１ｎｍ以上が好ましく、１０ｎｍ以上がより好ましい。 More specifically, in order to improve retention, it is preferable that the second inorganic fibers are easily deformed and flexible. Therefore, the second inorganic fibers, which are thin, preferably have an average fiber diameter of less than 1 μm, and more preferably 0.1 μm or less. However, if they are too thin, they are prone to breakage and their retention ability decreases. Furthermore, a large proportion of the fibers remain entangled in the insulating material A10, which not only reduces retention ability, but also leads to poor moldability and shape retention. Therefore, the average fiber diameter of the second inorganic fibers is preferably 1 nm or more, and more preferably 10 nm or more.
　なお、第２の無機繊維は、長くなりすぎると成形性や形状保持性が低下するため、第２の無機繊維の繊維長は０．１ｍｍ以下であることが好ましい。さらに、第２の無機繊維は、短すぎても形状保持性や機械的強度が低下するため、繊維長を１μｍ以上とすることが好ましい。 If the second inorganic fibers are too long, their moldability and shape retention will decrease, so it is preferable that the fiber length of the second inorganic fibers is 0.1 mm or less. Furthermore, if the second inorganic fibers are too short, their shape retention and mechanical strength will decrease, so it is preferable that the fiber length be 1 μm or more.
　また、第２の無機繊維は、樹枝状又は縮れ状であることが好ましい。第２の無機繊維がこのような形状であると、無機粒子と良好に絡み合い、保持能力が向上する。また、断熱材Ａ１０が押圧力や風圧を受けた際に、第２の無機繊維が滑って移動することが抑制され、このことにより、特に外部からの押圧力や衝撃に抗する機械的強度が向上する。 The second inorganic fibers are preferably dendritic or curly. When the second inorganic fibers have such a shape, they are well entangled with the inorganic particles, improving the retention capacity. Furthermore, when the insulating material A10 is subjected to pressure or wind pressure, the second inorganic fibers are prevented from sliding and moving, which improves the mechanical strength, particularly against external pressure and impact.
　なお、樹枝状とは、２次元的又は３次元的に枝分かれした構造であり、例えば羽毛状、テトラポット形状、放射線状、立体網目状である。 Note that dendritic refers to a two-dimensional or three-dimensional branched structure, such as feather-like, tetrapod-like, radial, or three-dimensional mesh-like.
　第２の無機繊維が樹枝状である場合に、その平均繊維径は、ＳＥＭによって幹部及び枝部の径を数点測定し、これらの平均値を算出することにより得ることができる。 When the second inorganic fiber is dendritic, its average fiber diameter can be obtained by measuring the diameters of the trunk and branches at several points using an SEM and calculating the average value.
　また、縮れ状とは、繊維が様々な方向に屈曲した構造である。縮れ形態を定量化する方法の一つとして、電子顕微鏡写真からその捲縮度を算出することが知られており、例えば下記式から算出することができる。
　捲縮度（％）＝（繊維長さ－繊維末端間距離）／（繊維長さ）×１００
　ここで、繊維長さ、繊維末端間距離ともに電子顕微鏡写真上での測定値である。すなわち、２次元平面上へ投影された繊維長、繊維末端間距離であり、現実の値よりも短くなっている。この式に基づき、第２の無機繊維の捲縮度は１０％以上が好ましく、３０％以上がより好ましい。捲縮度が小さいと、保持能力が低下し、第２の無機繊維同士、第１の無機繊維と第２の無機繊維との絡み合い（ネットワーク）が形成されにくくなる。 The term "crimped" refers to a structure in which fibers are bent in various directions. As a method for quantifying the crimped form, it is known to calculate the crimp degree from an electron microscope photograph, and for example, it can be calculated from the following formula.
Crimp degree (%)=(fiber length−distance between fiber ends)/(fiber length)×100
Here, both the fiber length and the distance between the fiber ends are measured values on an electron microscope photograph. That is, the fiber length and the distance between the fiber ends are projected onto a two-dimensional plane, and are shorter than the actual values. Based on this formula, the crimp degree of the second inorganic fiber is preferably 10% or more, and more preferably 30% or more. If the crimp degree is small, the retention ability decreases, and it becomes difficult to form entanglements (networks) between the second inorganic fibers and between the first inorganic fibers and the second inorganic fibers.
（ガラス転移点が互いに異なる２種の無機繊維）
　２種の無機繊維を含有する場合に、第１の無機繊維は非晶質の繊維であり、第２の無機繊維は、第１の無機繊維よりガラス転移点が高い非晶質の繊維、及び結晶質の繊維から選択される少なくとも１種の繊維であることが好ましい。 (Two types of inorganic fibers with different glass transition temperatures)
When two types of inorganic fibers are contained, it is preferable that the first inorganic fibers are amorphous fibers, and the second inorganic fibers are at least one type of fibers selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers.
　結晶質の無機繊維の融点は、通常非晶質の無機繊維のガラス転移点より高い。そのため、第１の無機繊維は、高熱に晒されると、その表面が第２の無機繊維より先に軟化して、無機粒子を結着する。したがって、第１の無機繊維を含有させることにより、断熱材Ａ１０の機械的強度を向上させることができる。 The melting point of crystalline inorganic fibers is usually higher than the glass transition point of amorphous inorganic fibers. Therefore, when exposed to high heat, the surface of the first inorganic fiber softens before the second inorganic fiber, and bonds the inorganic particles. Therefore, by including the first inorganic fiber, the mechanical strength of the insulation material A10 can be improved.
　第１の無機繊維としては、具体的には、融点が７００℃未満である無機繊維が好ましく、多くの非晶質の無機繊維を用いることができる。中でも、ＳｉＯ２を含む繊維であることが好ましく、安価で、入手も容易で、取扱い性等に優れることから、ガラス繊維であることがより好ましい。 Specifically, the first inorganic fiber is preferably an inorganic fiber having a melting point of less than 700° C., and many amorphous inorganic fibers can be used. Among them, fibers containing SiO 2 are preferable, and glass fibers are more preferable because they are inexpensive, easily available, and excellent in handleability.
　第２の無機繊維は、上述のとおり、第１の無機繊維よりガラス転移点が高い非晶質の繊維、及び結晶質の繊維から選択される少なくとも１種からなる繊維である。第２の無機繊維としては、多くの結晶性の無機繊維を用いることができる。 As described above, the second inorganic fiber is at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fiber and crystalline fibers. Many crystalline inorganic fibers can be used as the second inorganic fiber.
　第２の無機繊維が結晶質の繊維からなるものであるか、又は第１の無機繊維よりもガラス転移点が高いものであると、高熱にさらされたときに、第１の無機繊維が軟化しても、第２の無機繊維は溶融又は軟化しない。したがって、例えば電池モジュールに適用した場合、熱暴走が起こっても形状を維持する。 If the second inorganic fiber is made of crystalline fiber or has a higher glass transition point than the first inorganic fiber, the second inorganic fiber will not melt or soften when exposed to high heat, even if the first inorganic fiber softens. Therefore, when applied to a battery module, for example, the shape will be maintained even if thermal runaway occurs.
　また、第２の無機繊維が溶融又は軟化しないと、粒子間、無機粒子と繊維との間、及び各繊維間における微小な空間が維持されるため、空気による断熱効果が発揮される。 In addition, if the second inorganic fibers do not melt or soften, tiny spaces are maintained between the particles, between the inorganic particles and the fibers, and between each fiber, providing an insulating effect through air.
　第２の無機繊維が結晶質である場合に、具体的には、シリカ繊維、アルミナ繊維、アルミナシリケート繊維、ジルコニア繊維、カーボンファイバ、ソルブルファイバ、リフラクトリーセラミックファイバ、エアロゲル複合材、マグネシウムシリケート繊維、アルカリアースシリケート繊維、チタン酸カリウム繊維等のセラミックス系繊維、ガラス繊維、グラスウール等のガラス系繊維、ロックウール、バサルトファイバ、上記以外の鉱物系繊維として、ウォラストナイト等の天然鉱物系繊維等を使用することができる。 When the second inorganic fiber is crystalline, specific examples of the fibers that can be used include ceramic fibers such as silica fiber, alumina fiber, alumina silicate fiber, zirconia fiber, carbon fiber, soluble fiber, refractory ceramic fiber, aerogel composite material, magnesium silicate fiber, alkaline earth silicate fiber, and potassium titanate fiber; glass fibers, glass fibers such as glass wool, rock wool, and basalt fiber; and natural mineral fibers such as wollastonite as mineral fibers other than those mentioned above.
　また、融点が１０００℃を超えるものであると、電池セルの熱暴走が発生しても、第２の無機繊維は溶融又は軟化せず、その形状を維持することができるため、好適に使用することができる。上記第２の無機繊維として挙げられた繊維のうち、例えば、シリカ繊維、アルミナ繊維及びアルミナシリケート繊維等のセラミックス系繊維、並びに天然鉱物系繊維を使用することがより好ましく、この中でも融点が１０００℃を超えるものを使用することが更に好ましい。 Furthermore, if the melting point exceeds 1000°C, the second inorganic fiber will not melt or soften and will be able to maintain its shape even if thermal runaway occurs in the battery cell, and therefore can be used preferably. Of the fibers listed above as the second inorganic fiber, it is more preferable to use ceramic fibers such as silica fibers, alumina fibers, and alumina silicate fibers, as well as natural mineral fibers, and it is even more preferable to use fibers with a melting point exceeding 1000°C.
　また、第２の無機繊維が非晶質である場合であっても、第１の無機繊維よりもガラス転移点が高い繊維であれば、使用することができる。例えば、第１の無機繊維よりガラス転移点が高いガラス繊維を第２の無機繊維として用いてもよい。 Even if the second inorganic fiber is amorphous, it can be used as long as it has a higher glass transition point than the first inorganic fiber. For example, glass fiber with a higher glass transition point than the first inorganic fiber may be used as the second inorganic fiber.
　なお、第２の無機繊維としては、例示した種々の無機繊維を単独で使用してもよいし、２種以上を混合使用してもよい。 As the second inorganic fiber, the various inorganic fibers exemplified above may be used alone or two or more types may be mixed and used.
　上記のとおり、第１の無機繊維は第２の無機繊維よりもガラス転移点が低く、高熱にさらされたときに、第１の無機繊維が先に軟化するため、第１の無機繊維で無機粒子を結着することができる。しかし、例えば、第２の無機繊維が非晶質であって、その繊維径が第１の無機繊維の繊維径よりも細い場合に、第１の無機繊維と第２の無機繊維とのガラス転移点が接近していると、第２の無機繊維が先に軟化するおそれがある。したがって、第２の無機繊維が非晶質の繊維である場合に、第２の無機繊維のガラス転移点は、第１の無機繊維のガラス転移点よりも１００℃以上高いことが好ましく、３００℃以上高いことがより好ましい。 As described above, the first inorganic fiber has a lower glass transition point than the second inorganic fiber, and when exposed to high heat, the first inorganic fiber softens first, allowing the first inorganic fiber to bind the inorganic particles. However, for example, when the second inorganic fiber is amorphous and has a smaller fiber diameter than the first inorganic fiber, if the glass transition points of the first and second inorganic fibers are close to each other, there is a risk that the second inorganic fiber will soften first. Therefore, when the second inorganic fiber is an amorphous fiber, the glass transition point of the second inorganic fiber is preferably 100°C or more higher than the glass transition point of the first inorganic fiber, and more preferably 300°C or more higher.
　なお、第１の無機繊維の繊維長は、１００ｍｍ以下であることが好ましく、０．１ｍｍ以上とすることが好ましい。第２の無機繊維の繊維長は、０．１ｍｍ以下であることが好ましい。これらの理由については、上記したとおりである。 The fiber length of the first inorganic fiber is preferably 100 mm or less, and more preferably 0.1 mm or more. The fiber length of the second inorganic fiber is preferably 0.1 mm or less. The reasons for this are as described above.
（ガラス転移点及び平均繊維径が互いに異なる２種の無機繊維）
　２種の無機繊維を含有する場合に、第１の無機繊維は非晶質の繊維であり、第２の無機繊維は、第１の無機繊維よりガラス転移点が高い非晶質の繊維、及び、結晶質の繊維から選択される少なくとも１種の繊維であり、第１の無機繊維の平均繊維径が、第２の無機繊維の平均繊維径よりも大きいことが好ましい。 (Two types of inorganic fibers having different glass transition temperatures and average fiber diameters)
When two types of inorganic fibers are contained, it is preferable that the first inorganic fibers are amorphous fibers, the second inorganic fibers are at least one type of fibers selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers, and the average fiber diameter of the first inorganic fibers is larger than the average fiber diameter of the second inorganic fibers.
　上述のとおり、第１の無機繊維の平均繊維径が、第２の無機繊維よりも大きいことが好ましい。また、太径の第１の無機繊維が非晶質の繊維であり、細径の第２の無機繊維が、第１の無機繊維よりガラス転移点が高い非晶質の繊維、及び結晶質の繊維から選択される少なくとも１種からなる繊維であることが好ましい。これにより、第１の無機繊維のガラス転移点が低く、早く軟化するため、温度の上昇に伴って膜状となって硬くなる。一方、細径である第２の無機繊維が、第１の無機繊維よりガラス転移点が高い非晶質の繊維、及び結晶質の繊維から選択される少なくとも１種からなる繊維であると、温度が上昇しても細径の第２の無機繊維が繊維の形状で残存するため、断熱材Ａ１０の構造を保持し、粉落ちを防止することができる。 As described above, it is preferable that the average fiber diameter of the first inorganic fibers is larger than that of the second inorganic fibers. It is also preferable that the thick first inorganic fibers are amorphous fibers, and the thin second inorganic fibers are at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers. This allows the first inorganic fibers to have a low glass transition point and soften quickly, so that they become film-like and harden as the temperature rises. On the other hand, if the thin second inorganic fibers are at least one type of fiber selected from amorphous fibers having a higher glass transition point than the first inorganic fibers and crystalline fibers, the thin second inorganic fibers remain in the fiber shape even when the temperature rises, so the structure of the insulating material A10 can be maintained and powder fall can be prevented.
　なお、この場合であっても、第１の無機繊維の繊維長は、１００ｍｍ以下であることが好ましく、０．１ｍｍ以上とすることが好ましい。第２の無機繊維の繊維長は、０．１ｍｍ以下であることが好ましい。これらの理由については、上記したとおりである。 Even in this case, the fiber length of the first inorganic fiber is preferably 100 mm or less, and more preferably 0.1 mm or more. The fiber length of the second inorganic fiber is preferably 0.1 mm or less. The reasons for this are as described above.
（第１の無機繊維及び第２の無機繊維の各含有量）
　２種の無機繊維を含有する場合に、第１の無機繊維の含有量は、断熱材Ａ１０の全質量に対して３質量％以上３０質量％以下であることが好ましく、第２の無機繊維の含有量は、断熱材Ａ１０の全質量に対して３質量％以上３０質量％以下であることが好ましい。 (Contents of First Inorganic Fibers and Second Inorganic Fibers)
When two types of inorganic fibers are contained, the content of the first inorganic fibers is preferably 3 mass% or more and 30 mass% or less relative to the total mass of the insulation material A10, and the content of the second inorganic fibers is preferably 3 mass% or more and 30 mass% or less relative to the total mass of the insulation material A10.
　また、第１の無機繊維の含有量は、断熱材Ａ１０の全質量に対して、５質量％以上１５質量％以下であることがより好ましく、第２の無機繊維の含有量は、断熱材Ａ１０の全質量に対して、５質量％以上１５質量％以下であることがより好ましい。このような含有量にすることにより、第１の無機繊維による形状保持性や押圧力耐性、抗風圧性、及び第２の無機繊維による無機粒子の保持能力がバランスよく発現される。 Moreover, it is more preferable that the content of the first inorganic fibers is 5% by mass or more and 15% by mass or less, based on the total mass of the insulating material A10, and it is more preferable that the content of the second inorganic fibers is 5% by mass or more and 15% by mass or less, based on the total mass of the insulating material A10. By setting the content at such levels, the shape retention, pressure resistance, and wind pressure resistance of the first inorganic fibers, and the inorganic particle retention ability of the second inorganic fibers are expressed in a balanced manner.
（無機粒子）
　無機粒子は、平均二次粒子径が０．０１μｍ以上であると、入手しやすく、製造コストの上昇を抑制することができる。また、２００μｍ以下であると、所望の断熱効果を得ることができる。したがって、無機粒子の平均二次粒子径は、０．０１μｍ以上２００μｍ以下であることが好ましく、０．０５μｍ以上１００μｍ以下であることがより好ましい。 (Inorganic particles)
When the inorganic particles have an average secondary particle diameter of 0.01 μm or more, they are easily available and the increase in production costs can be suppressed. When the inorganic particles have an average secondary particle diameter of 200 μm or less, the desired heat insulating effect can be obtained. Therefore, the average secondary particle diameter of the inorganic particles is preferably 0.01 μm or more and 200 μm or less, and more preferably 0.05 μm or more and 100 μm or less.
　無機粒子として、単一の無機粒子を使用してもよいし、２種以上の無機粒子（第１の無機粒子及び第２の無機粒子）を組み合わせて使用してもよい。第１の無機粒子及び第２の無機粒子としては、熱伝達抑制効果の観点から、酸化物粒子、炭化物粒子、窒化物粒子及び無機水和物粒子から選択される少なくとも１種の無機材料からなる粒子を使用することが好ましく、酸化物粒子を使用することがより好ましい。また、第１の無機粒子及び第２の無機粒子の形状についても特に限定されないが、ナノ粒子、中空粒子及び多孔質粒子から選択される少なくとも１種を含むことが好ましく、具体的には、シリカナノ粒子、金属酸化物粒子、マイクロポーラス粒子や中空シリカ粒子等の無機バルーン、熱膨張性無機材料からなる粒子、含水多孔質体からなる粒子等を使用することもできる。 As the inorganic particles, a single inorganic particle may be used, or two or more types of inorganic particles (first inorganic particles and second inorganic particles) may be used in combination. From the viewpoint of the heat transfer suppression effect, it is preferable to use particles made of at least one inorganic material selected from oxide particles, carbide particles, nitride particles, and inorganic hydrate particles as the first inorganic particles and the second inorganic particles, and it is more preferable to use oxide particles. In addition, the shape of the first inorganic particles and the second inorganic particles is not particularly limited, but it is preferable to include at least one type selected from nanoparticles, hollow particles, and porous particles. Specifically, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of thermally expandable inorganic materials, particles made of hydrous porous bodies, etc. can also be used.
　なお、２種以上の熱伝達抑制効果が互いに異なる無機粒子を併用すると、多段に冷却することができ、吸熱作用をより広い温度範囲で発現できる。具体的には、大径粒子と小径粒子とを混合使用することが好ましい。例えば、一方の無機粒子として、ナノ粒子を使用する場合に、他方の無機粒子として、金属酸化物からなる無機粒子を含むことが好ましい。以下、小径の無機粒子を第１の無機粒子、大径の無機粒子を第２の無機粒子として、無機粒子についてさらに詳細に説明する。 When two or more types of inorganic particles with different heat transfer suppression effects are used in combination, multi-stage cooling is possible, and the heat absorption effect can be expressed over a wider temperature range. Specifically, it is preferable to use a mixture of large-diameter particles and small-diameter particles. For example, when nanoparticles are used as one of the inorganic particles, it is preferable to include inorganic particles made of a metal oxide as the other inorganic particle. Inorganic particles will be described in more detail below, with small-diameter inorganic particles referred to as first inorganic particles and large-diameter inorganic particles referred to as second inorganic particles.
（第１の無機粒子）
（酸化物粒子）
　第１の無機粒子として、酸化物粒子が好ましい。酸化物粒子は屈折率が高く、光を乱反射させる効果が強いため、特に異常発熱などの高熱度領域において輻射伝熱を抑制することができる。酸化物粒子としては、シリカ粒子、チタニア粒子、ジルコニア粒子、ジルコン粒子、チタン酸バリウム粒子、酸化亜鉛粒子及びアルミナ粒子から選択された少なくとも１種の粒子を使用することができる。特に、シリカは断熱性が高い成分であり、チタニアは他の金属酸化物と比較して屈折率が高い成分であって、５００℃以上の高熱度領域において光を乱反射させ輻射熱を遮る効果が高いため、酸化物粒子としてシリカ及びチタニアを用いることが最も好ましい。 (First inorganic particles)
(Oxide particles)
As the first inorganic particle, oxide particles are preferred. Oxide particles have a high refractive index and a strong effect of diffusely reflecting light, so that they can suppress radiant heat transfer, especially in high heat regions such as abnormal heat generation. As the oxide particles, at least one type of particle selected from silica particles, titania particles, zirconia particles, zircon particles, barium titanate particles, zinc oxide particles, and alumina particles can be used. In particular, silica is a component with high heat insulation properties, and titania is a component with a high refractive index compared to other metal oxides, and has a high effect of diffusely reflecting light and blocking radiant heat in high heat regions of 500°C or more, so it is most preferable to use silica and titania as oxide particles.
　酸化物粒子の粒子径は、輻射熱を反射する効果に影響を与えることがあるため、平均一次粒子径を所定の範囲に限定すると、より一層高い断熱性を得ることができる。すなわち、酸化物粒子の平均一次粒子径が０．００１μｍ以上であると、加熱に寄与する光の波長よりも十分に大きく、光を効率よく乱反射させるため、５００℃以上の高熱度領域において熱伝達抑制シート内における熱の輻射伝熱が抑制され、より一層断熱性を向上させることができる。一方、酸化物粒子の平均一次粒子径が５０μｍ以下であると、圧縮されても粒子間の接点や数が増えず、伝導伝熱のパスを形成しにくいため、特に伝導伝熱が支配的な通常温度域の断熱性への影響を小さくすることができる。 Since the particle size of the oxide particles can affect the effect of reflecting radiant heat, by limiting the average primary particle size to a specified range, even higher thermal insulation can be obtained. In other words, if the average primary particle size of the oxide particles is 0.001 μm or more, it is sufficiently larger than the wavelength of light that contributes to heating, and efficiently diffuses light, so that the radiant heat transfer within the heat transfer suppression sheet is suppressed in high heat ranges of 500°C or more, and thermal insulation can be further improved. On the other hand, if the average primary particle size of the oxide particles is 50 μm or less, the number and number of contact points between particles do not increase even when compressed, making it difficult to form a path for conductive heat transfer, and therefore the impact on thermal insulation can be reduced, especially in normal temperature ranges where conductive heat transfer is dominant.
　なお、本実施形態において平均一次粒子径は、顕微鏡で粒子を観察し、標準スケールと比較し、任意の粒子１０個の平均をとることにより求めることができる。 In this embodiment, the average primary particle size can be determined by observing the particles under a microscope, comparing with a standard scale, and taking the average of any 10 particles.
（ナノ粒子）
　第１の無機粒子としてナノ粒子が好ましく、ナノ粒子は低密度であるため伝導伝熱を抑制し、更に空隙が細かく分散するため、対流伝熱を抑制する優れた断熱性を得ることができる。このため、通常の常温域の電池使用時において、隣接するナノ粒子間の熱の伝導を抑制することができる点で、ナノ粒子を使用することが好ましい。 (Nanoparticles)
Nanoparticles are preferred as the first inorganic particles, and since nanoparticles have a low density and thus suppress conductive heat transfer, and furthermore, since the voids are finely dispersed, excellent heat insulation properties can be obtained that suppress convective heat transfer. Therefore, it is preferred to use nanoparticles in that the conduction of heat between adjacent nanoparticles can be suppressed during normal use of the battery in the normal temperature range.
　なお、ナノ粒子とは、球形又は球形に近い平均一次粒子径が１μｍ未満のナノメートルオーダーの粒子を表す。 Nanoparticles refer to particles that are spherical or nearly spherical, with an average primary particle size of less than 1 μm, on the order of nanometers.
　また、酸化物粒子として、平均一次粒子径が小さいナノ粒子を使用すると、電池セルの熱暴走に伴う膨張によって断熱材の内部密度が上がった場合であっても、断熱材の伝導伝熱の上昇を抑制することができる。これは、ナノ粒子が静電気による反発力で粒子間に細かな空隙ができやすく、かさ密度が低いため、クッション性があるように粒子が充填されるからであると考えられる。 Furthermore, if nanoparticles with a small average primary particle size are used as the oxide particles, it is possible to suppress an increase in the conductive heat transfer of the insulation material, even if the internal density of the insulation material increases due to expansion caused by thermal runaway of the battery cell. This is thought to be because nanoparticles are prone to creating small gaps between particles due to electrostatic repulsion, and because they have a low bulk density, the particles are packed together to provide a cushioning effect.
　なお、第１の無機粒子としてナノ粒子を使用する場合に、上記ナノ粒子の定義に沿ったものであれば、材質について特に限定されない。例えば、シリカナノ粒子は、断熱性が高い材料であることに加えて、粒子同士の接点が小さいため、シリカナノ粒子により伝導される熱量は、粒子径が大きいシリカ粒子を使用した場合と比較して小さくなる。また、一般的に入手されるシリカナノ粒子は、かさ密度が０．１（ｇ／ｃｍ３）程度であるため、例えば、断熱材に対して大きな圧縮応力が加わった場合であっても、シリカナノ粒子同士の接点の大きさ（面積）や数が著しく大きくなることはなく、断熱性を維持することができる。したがって、ナノ粒子としてはシリカナノ粒子を使用することが好ましい。シリカナノ粒子としては、湿式シリカ、乾式シリカ及びエアロゲル等を使用することができる。 In addition, when using nanoparticles as the first inorganic particles, the material is not particularly limited as long as it is in accordance with the definition of nanoparticles. For example, silica nanoparticles are a material with high heat insulation, and since the contact points between particles are small, the amount of heat conducted by silica nanoparticles is smaller than that when silica particles with a large particle diameter are used. In addition, since commonly available silica nanoparticles have a bulk density of about 0.1 (g/cm 3 ), for example, even when a large compressive stress is applied to the heat insulating material, the size (area) and number of contact points between silica nanoparticles do not become significantly large, and heat insulation can be maintained. Therefore, it is preferable to use silica nanoparticles as the nanoparticles. As the silica nanoparticles, wet silica, dry silica, aerogel, etc. can be used.
　ナノ粒子の平均一次粒子径を所定の範囲に限定すると、より一層高い断熱性を得ることができる。すなわち、ナノ粒子の平均一次粒子径を１ｎｍ以上１００ｎｍ以下とすると、特に５００℃未満の温度領域において、断熱材Ａ１０内における熱の対流伝熱及び伝導伝熱を抑制することができ、断熱性をより一層向上させることができる。また、圧縮応力が印加された場合であっても、ナノ粒子間に残った空隙と、多くの粒子間の接点が伝導伝熱を抑制し、断熱性を維持することができる。また、ナノ粒子の平均一次粒子径は、２ｎｍ以上であることがより好ましく、３ｎｍ以上であることが更に好ましい。一方、ナノ粒子の平均一次粒子径は、５０ｎｍ以下であることがより好ましく、１０ｎｍ以下であることが更に好ましい。 By limiting the average primary particle diameter of the nanoparticles to a predetermined range, it is possible to obtain even higher thermal insulation. In other words, by setting the average primary particle diameter of the nanoparticles to 1 nm or more and 100 nm or less, it is possible to suppress convective heat transfer and conductive heat transfer within the insulating material A10, particularly in the temperature range below 500°C, and it is possible to further improve the thermal insulation. Furthermore, even when compressive stress is applied, the gaps remaining between the nanoparticles and the contact points between many particles suppress conductive heat transfer, and it is possible to maintain the thermal insulation. Furthermore, it is more preferable that the average primary particle diameter of the nanoparticles is 2 nm or more, and even more preferable that it is 3 nm or more. On the other hand, it is more preferable that the average primary particle diameter of the nanoparticles is 50 nm or less, and even more preferable that it is 10 nm or less.
（無機水和物粒子）
　無機水和物粒子は、熱暴走を起こした電池セル等の熱源からの高熱を受けて熱分解開始温度以上になると熱分解し、自身が持つ結晶水を放出して熱源及びその周囲の温度を下げる、所謂「吸熱作用」を発現する。また、結晶水を放出した後は多孔質体となり、無数の空気孔により断熱作用を発現する。 (Inorganic hydrate particles)
When inorganic hydrate particles receive high heat from a heat source such as a thermal runaway battery cell and the temperature exceeds the temperature at which they start to decompose, they undergo thermal decomposition and release their own water of crystallization to lower the temperature of the heat source and its surroundings, thus exerting the so-called "endothermic effect." After releasing the water of crystallization, the particles become porous and exert a heat insulating effect due to the countless air holes.
　無機水和物の具体例として、水酸化アルミニウム（Ａｌ（ＯＨ）３）、水酸化マグネシウム（Ｍｇ（ＯＨ）２）、水酸化カルシウム（Ｃａ（ＯＨ）２）、水酸化亜鉛（Ｚｎ（ＯＨ）２）、水酸化鉄（Ｆｅ（ＯＨ）２）、水酸化マンガン（Ｍｎ（ＯＨ）２）、水酸化ジルコニウム（Ｚｒ（ＯＨ）２）、水酸化ガリウム（Ｇａ（ＯＨ）３）等が挙げられる。 Specific examples of inorganic hydrates include aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium hydroxide (Ca(OH) 2 ), zinc hydroxide (Zn(OH) 2 ), iron hydroxide (Fe(OH) 2 ), manganese hydroxide (Mn(OH) 2 ), zirconium hydroxide (Zr(OH) 2 ), and gallium hydroxide (Ga(OH) 3 ).
　例えば、水酸化アルミニウムは約３５％の結晶水を有しており、下記式に示すように、熱分解して結晶水を放出して吸熱作用を発現する。そして、結晶水を放出した後は多孔質体であるアルミナ（Ａｌ２Ｏ３）となり、断熱材として機能する。
　２Ａｌ（ＯＨ）３→Ａｌ２Ｏ３＋３Ｈ２Ｏ For example, aluminum hydroxide has about 35% water of crystallization, and as shown in the following formula, it thermally decomposes and releases water of crystallization, thereby exerting an endothermic effect. After releasing the water of crystallization, it becomes a porous body, alumina ( Al2O3 ), and functions as a thermal insulator.
2Al(OH) 3 →Al 2 O 3 +3H 2 O
　なお、熱暴走を起こした電池セルでは、２００℃を超える温度に急上昇し、７００℃付近まで温度上昇を続ける。したがって、無機粒子としては熱分解開始温度が２００℃以上である無機水和物からなることが好ましい。 In addition, in a battery cell that has experienced thermal runaway, the temperature rises rapidly to over 200°C and continues to rise to around 700°C. Therefore, it is preferable that the inorganic particles consist of inorganic hydrates whose thermal decomposition onset temperature is 200°C or higher.
　上記に挙げた無機水和物の熱分解開始温度は、水酸化アルミニウムは約２００℃、水酸化マグネシウムは約３３０℃、水酸化カルシウムは約５８０℃、水酸化亜鉛は約２００℃、水酸化鉄は約３５０℃、水酸化マンガンは約３００℃、水酸化ジルコニウムは約３００℃、水酸化ガリウムは約３００℃であり、いずれも熱暴走を起こした電池セルの急激な昇温の温度範囲とほぼ重なり、温度上昇を効率よく抑えることができることから、好ましい無機水和物であるといえる。 The thermal decomposition starting temperatures of the inorganic hydrates listed above are approximately 200°C for aluminum hydroxide, approximately 330°C for magnesium hydroxide, approximately 580°C for calcium hydroxide, approximately 200°C for zinc hydroxide, approximately 350°C for iron hydroxide, approximately 300°C for manganese hydroxide, approximately 300°C for zirconium hydroxide, and approximately 300°C for gallium hydroxide. All of these temperatures roughly overlap with the temperature range of the sudden temperature rise of a battery cell that has experienced thermal runaway, and can efficiently suppress the temperature rise, making these inorganic hydrates preferable.
　また、無機水和物粒子の平均粒子径が大きすぎると、断熱材Ａ１０の中心付近にある無機水和物粒子が、その熱分解温度に達するまでにある程度の時間を要するため、断熱材Ａ１０の中心付近の無機水和物粒子が熱分解しきれない場合がある。このため、無機水和物粒子の平均二次粒子径は、０．０１μｍ以上２００μｍ以下であることが好ましく、０．０５μｍ以上１００μｍ以下であることがより好ましい。 In addition, if the average particle size of the inorganic hydrate particles is too large, it will take some time for the inorganic hydrate particles near the center of the insulating material A10 to reach their thermal decomposition temperature, and the inorganic hydrate particles near the center of the insulating material A10 may not be completely thermally decomposed. For this reason, the average secondary particle size of the inorganic hydrate particles is preferably 0.01 μm or more and 200 μm or less, and more preferably 0.05 μm or more and 100 μm or less.
（熱膨張性無機材料からなる粒子）
　熱膨張性無機材料としては、バーミキュライト、ベントナイト、雲母、パーライト等を挙げることができる。 (Particles made of thermally expandable inorganic material)
Examples of the thermally expandable inorganic material include vermiculite, bentonite, mica, and perlite.
（含水多孔質体からなる粒子）
　含水多孔質体の具体例としては、ゼオライト、カオリナイト、モンモリロナイト、酸性白土、珪藻土、湿式シリカ、乾式シリカ、エアロゲル、マイカ、バーミキュライト等が挙げられる。 (Particles made of water-containing porous body)
Specific examples of the hydrous porous body include zeolite, kaolinite, montmorillonite, acid clay, diatomaceous earth, wet silica, dry silica, aerogel, mica, and vermiculite.
（無機バルーン）
　無機バルーンが含まれると、５００℃未満の温度領域において、断熱材Ａ１０内における熱の対流伝熱又は伝導伝熱を抑制することができ、断熱材Ａ１０の断熱性をより一層向上させることができる。 (Inorganic balloon)
When inorganic balloons are included, convective or conductive heat transfer within the insulating material A10 can be suppressed in the temperature range below 500° C., thereby further improving the insulating properties of the insulating material A10.
　無機バルーンとしては、シラスバルーン、シリカバルーン、フライアッシュバルーン、バーライトバルーン、及びガラスバルーンから選択された少なくとも１種を用いることができる。 As inorganic balloons, at least one selected from shirasu balloons, silica balloons, fly ash balloons, barite balloons, and glass balloons can be used.
　無機バルーンの含有量としては、断熱材Ａ１０の全質量に対し、６０質量％以下が好ましい。 The content of inorganic balloons is preferably 60 mass% or less relative to the total mass of the insulating material A10.
　また、無機バルーンの平均粒子径としては、１μｍ以上１００μｍ以下が好ましい。 The average particle size of the inorganic balloons is preferably 1 μm or more and 100 μm or less.
（第２の無機粒子）
　第２の無機粒子は、第１の無機粒子と材質や粒子径等が異なっていれば特に限定されない。第２の無機粒子としては、酸化物粒子、炭化物粒子、窒化物粒子、無機水和物粒子、シリカナノ粒子、金属酸化物粒子、マイクロポーラス粒子や中空シリカ粒子等の無機バルーン、熱膨張性無機材料からなる粒子、含水多孔質体からなる粒子等を使用することができ、これらの詳細については、上述のとおりである。 (Second Inorganic Particles)
The second inorganic particles are not particularly limited as long as they are different from the first inorganic particles in terms of material, particle size, etc. Examples of the second inorganic particles that can be used include oxide particles, carbide particles, nitride particles, inorganic hydrate particles, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of a thermally expandable inorganic material, particles made of a water-containing porous body, etc., and the details of these are as described above.
　なお、ナノ粒子は伝導伝熱が極めて小さいとともに、断熱材Ａ１０に圧縮応力が加わった場合であっても、優れた断熱性を維持することができる。また、チタニア等の金属酸化物粒子は、輻射熱を遮る効果が高い。さらに、大径の無機粒子と小径の無機粒子とを使用すると、大径の無機粒子同士の隙間に小径の無機粒子が入り込むことにより、より緻密な構造となり、熱伝達抑制効果を向上させることができる。したがって、上記第１の無機粒子として、ナノ粒子を使用した場合に、さらに、第２の無機粒子として、第１の無機粒子よりも大径である金属酸化物からなる粒子を、断熱材Ａ１０に含有させることが好ましい。 Nanoparticles have extremely low conductive heat transfer and can maintain excellent heat insulation even when compressive stress is applied to the insulating material A10. Metal oxide particles such as titania are highly effective at blocking radiant heat. Furthermore, when large-diameter inorganic particles and small-diameter inorganic particles are used, the small-diameter inorganic particles enter the gaps between the large-diameter inorganic particles, resulting in a denser structure and improving the heat transfer suppression effect. Therefore, when nanoparticles are used as the first inorganic particles, it is preferable to further include particles made of a metal oxide larger in diameter than the first inorganic particles as the second inorganic particles in the insulating material A10.
　金属酸化物としては、酸化ケイ素、酸化チタン、酸化アルミニウム、チタン酸バリウム、酸化亜鉛、ジルコン、酸化ジルコニウム等を挙げることができる。特に、酸化チタン（チタニア）は他の金属酸化物と比較して屈折率が高い成分であり、５００℃以上の高熱度領域において光を乱反射させ輻射熱を遮る効果が高いため、チタニアを用いることが最も好ましい。 Metal oxides include silicon oxide, titanium oxide, aluminum oxide, barium titanate, zinc oxide, zircon, zirconium oxide, etc. In particular, titanium oxide (titania) has a higher refractive index than other metal oxides, and is highly effective at scattering light and blocking radiant heat in high heat regions of 500°C or higher, making it most preferable to use titania.
　第２の無機粒子の平均一次粒子径は、１μｍ以上５０μｍ以下であると、５００℃以上の高熱度領域で効率よく輻射伝熱を抑制することができる。第２の無機粒子の平均一次粒子径は、５μｍ以上３０μｍ以下であることが更に好ましく、１０μｍ以下であることが最も好ましい。 If the average primary particle diameter of the second inorganic particles is 1 μm or more and 50 μm or less, radiative heat transfer can be efficiently suppressed in a high heat range of 500°C or more. It is more preferable that the average primary particle diameter of the second inorganic particles is 5 μm or more and 30 μm or less, and most preferably 10 μm or less.
（その他の配合材料）
　断熱材Ａ１０には、上記第１の無機繊維及び第２の無機繊維の他に、異なる無機繊維が含まれていてもよい。また、有機バインダや有機繊維、無機粒子を含んでもよい。 (Other compounding materials)
The heat insulating material A10 may contain different inorganic fibers in addition to the first inorganic fibers and the second inorganic fibers. The heat insulating material A10 may also contain an organic binder, organic fibers, and inorganic particles.
（樹脂バインダ）
　上記無機繊維は、樹脂バインダにより結着することもできる。樹脂バインダとしては、後述する有機繊維のガラス転移点よりも低いガラス転移点を有するものであれば、特に限定されない。例えば、スチレン－ブタジエン樹脂、アクリル樹脂、シリコン－アクリル樹脂及びスチレン樹脂から選択された少なくとも１種を含む樹脂バインダを使用することができる。 (Resin binder)
The inorganic fibers can also be bound by a resin binder. There are no particular limitations on the resin binder as long as it has a glass transition point lower than that of the organic fibers described below. For example, a resin binder containing at least one selected from styrene-butadiene resin, acrylic resin, silicon-acrylic resin, and styrene resin can be used.
　樹脂バインダのガラス転移点は特に規定しないが、－１０℃以上であることが好ましい。なお、樹脂バインダのガラス転移点が室温以上であると、樹脂バインダを有する断熱材が室温で使用された場合に、断熱材Ａ１０の強度をより一層向上させることができる。したがって、樹脂バインダのガラス転移点は、例えば２０℃以上であることがより好ましく、３０℃以上であることがさらに好ましく、５０℃以上であることがさらにより好ましく、６０℃以上であることが特に好ましい。 The glass transition point of the resin binder is not particularly specified, but is preferably -10°C or higher. If the glass transition point of the resin binder is room temperature or higher, the strength of the insulating material A10 can be further improved when an insulating material having the resin binder is used at room temperature. Therefore, the glass transition point of the resin binder is more preferably 20°C or higher, even more preferably 30°C or higher, even more preferably 50°C or higher, and particularly preferably 60°C or higher.
　樹脂バインダの含有量は、断熱材Ａ１０の全質量に対して０．５質量％以上であることが好ましく、１質量％以上であることがより好ましい。また、２０質量％以下であることが好ましく、１０質量％以下であることがより好ましい。 The resin binder content is preferably 0.5% by mass or more, and more preferably 1% by mass or more, relative to the total mass of the insulation material A10. It is also preferable that the content is 20% by mass or less, and more preferably 10% by mass or less.
（有機繊維）
　上記無機繊維の他に、有機繊維を含有してもよい。有機繊維としては、例えば、ポリビニルアルコール（ＰＶＡ）繊維、ポリエチレン繊維、ナイロン繊維、ポリウレタン繊維及びエチレン－ビニルアルコール共重合体繊維から選択された少なくとも１種を使用することができる。 (Organic Fiber)
In addition to the inorganic fibers, organic fibers may be contained. As the organic fibers, for example, at least one selected from polyvinyl alcohol (PVA) fibers, polyethylene fibers, nylon fibers, polyurethane fibers, and ethylene-vinyl alcohol copolymer fibers can be used.
　なお、断熱材の製造は抄造法にて行うことができるが、その際に加熱温度を２５０℃よりも高くすることは困難であるため、有機繊維のガラス転移点は、２５０℃以下とすることが好ましく、２００℃以下とすることがより好ましい。 Insulating materials can be manufactured using a papermaking method, but since it is difficult to raise the heating temperature above 250°C, it is preferable for the glass transition point of the organic fiber to be 250°C or lower, and more preferably 200°C or lower.
　有機繊維のガラス転移点の下限値も特に限定されないが、上記樹脂バインダのガラス転移点との差が１０℃以上であれば、製造時の冷却工程において、半溶融状態であった有機繊維が完全に固化した後に、樹脂バインダが固化するため、樹脂バインダによる骨格の補強効果を十分に得ることができる。したがって、樹脂バインダのガラス転移点と、有機繊維のガラス転移点との差は、１０℃以上であることが好ましく、３０℃以上であることがより好ましい。 There is no particular lower limit to the glass transition point of the organic fiber, but if the difference with the glass transition point of the resin binder is 10°C or more, the resin binder will solidify after the organic fiber, which was in a semi-molten state, has completely solidified during the cooling process during production, and therefore the resin binder can fully reinforce the skeleton. Therefore, the difference between the glass transition point of the resin binder and the glass transition point of the organic fiber is preferably 10°C or more, and more preferably 30°C or more.
　一方、両者のガラス転移点の差が１３０℃以下であると、有機繊維が完全に固化してから、樹脂バインダが固化し始めるまでの時間を適切に調整することができ、樹脂バインダが良好な分散状態のまま固化するため、より一層骨格の補強効果を得ることができる。したがって、樹脂バインダのガラス転移点と、有機繊維のガラス転移点との差は、１３０℃以下であることが好ましく、１２０℃以下であることがより好ましく、１００℃以下であることがさらに好ましく、８０℃以下であることがさらにより好ましく、７０℃以下であることが特に好ましい。 On the other hand, if the difference in glass transition point between the two is 130°C or less, the time from when the organic fibers have completely solidified until the resin binder begins to solidify can be appropriately adjusted, and the resin binder solidifies while remaining in a well-dispersed state, providing an even greater skeletal reinforcement effect. Therefore, the difference between the glass transition point of the resin binder and the glass transition point of the organic fibers is preferably 130°C or less, more preferably 120°C or less, even more preferably 100°C or less, even more preferably 80°C or less, and particularly preferably 70°C or less.
　また、２種類以上の有機繊維を含むこともできるが、その場合に、少なくとも１種の有機繊維が骨格として作用する有機繊維、すなわち、樹脂バインダのガラス転移点よりも高いガラス転移点を有する有機繊維であればよい。なお、樹脂バインダのガラス転移点と、少なくとも１種の有機繊維のガラス転移点との差は、上記と同様に、１０℃以上であることが好ましく、３０℃以上であることがより好ましく、１３０℃以下であることが好ましく、１２０℃以下であることがより好ましく、１００℃以下であることがさらに好ましく、８０℃以下であることがさらにより好ましく、７０℃以下であることが特に好ましい。 It is also possible to include two or more types of organic fibers, in which case at least one type of organic fiber should act as the skeleton, i.e., should have a glass transition point higher than that of the resin binder. As above, the difference between the glass transition point of the resin binder and the glass transition point of the at least one type of organic fiber is preferably 10°C or more, more preferably 30°C or more, preferably 130°C or less, more preferably 120°C or less, even more preferably 100°C or less, even more preferably 80°C or less, and particularly preferably 70°C or less.
　有機繊維及び樹脂バインダの含有量が適切に制御されていると、有機繊維による骨格としての機能を十分に得ることができるとともに、樹脂バインダによる骨格の補強効果を十分に得ることができる。有機繊維の含有量は、断熱材Ａ１０の全質量に対して０．５質量％以上であることが好ましく、１質量％以上であることがより好ましい。また、１２質量％以下であることが好ましく、８質量％以下であることがより好ましい。なお、樹脂バインダのガラス転移点よりも高いガラス転移点を有する複数の有機繊維を含む場合に、これら複数の有機繊維の合計量が、上記有機繊維の含有量の範囲内であることが好ましい。 When the organic fiber and resin binder contents are appropriately controlled, the organic fiber can fully function as a skeleton, and the resin binder can fully reinforce the skeleton. The organic fiber content is preferably 0.5 mass% or more, and more preferably 1 mass% or more, relative to the total mass of the insulation material A10. It is also preferable that the organic fiber content is 12 mass% or less, and more preferably 8 mass% or less. When the insulation material A10 contains multiple organic fibers having a glass transition point higher than the glass transition point of the resin binder, it is preferable that the total amount of these multiple organic fibers is within the range of the organic fiber content.
　上述のとおり、２種類以上の有機繊維を含む場合に、少なくとも１種の有機繊維が、樹脂バインダのガラス転移点よりも高いガラス転移点を有するものであればよいが、その他の有機繊維として、ガラス転移点を有さない結晶状態の有機繊維を含有することがより好ましい。 As mentioned above, when two or more types of organic fibers are included, at least one of the organic fibers should have a glass transition point higher than that of the resin binder, but it is more preferable that the other organic fibers include organic fibers in a crystalline state that do not have a glass transition point.
　ガラス転移点を有さない結晶状態の有機繊維を含有することもできるが、この結晶状態の有機繊維は軟化点を持たないため、骨格となる有機繊維が軟化するような高熱に晒された場合であっても、断熱材Ａ１０の全体としての強度を維持することができる。また、結晶状態の有機繊維を含有することにより、常温において、この有機繊維も断熱材Ａ１０の骨格として作用する。したがって、断熱材Ａ１０の柔軟性や取り扱い性を向上させることができる。 It is also possible to include crystalline organic fibers that do not have a glass transition point, but because these crystalline organic fibers do not have a softening point, the overall strength of the insulating material A10 can be maintained even when exposed to high heat that would soften the organic fibers that form the skeleton. Furthermore, by including crystalline organic fibers, these organic fibers also act as the skeleton of the insulating material A10 at room temperature. This can therefore improve the flexibility and ease of handling of the insulating material A10.
　なお、結晶状態の有機繊維としては、ポリエステル（ＰＥＴ）繊維が挙げられる。 An example of a crystalline organic fiber is polyester (PET) fiber.
　また、断熱材Ａ１０の製造において抄造法を行う際に、分散液として水を使用することが好ましいが、有機繊維は水への溶解度が低いことが好ましい。水への溶解度を示す指標として「水中溶解温度」を使用できるが、有機繊維の水中溶解温度は６０℃以上であることが好ましく、７０℃以上であることがより好ましく、８０℃以上であることがさらに好ましい。 In addition, when performing the papermaking method in the manufacture of the insulating material A10, it is preferable to use water as the dispersion liquid, and it is preferable that the organic fibers have low solubility in water. The "dissolution temperature in water" can be used as an indicator of solubility in water, and the dissolution temperature in water of the organic fibers is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher.
　有機繊維の繊維長についても特に限定されないが、成形性や加工性を確保する観点から、平均繊維長は１０ｍｍ以下とすることが好ましい。一方、有機繊維を骨格として機能させ、断熱材の圧縮強度を確保する観点から、平均繊維長は０．５ｍｍ以上とすることが好ましい。 The fiber length of the organic fibers is not particularly limited, but from the viewpoint of ensuring moldability and processability, it is preferable that the average fiber length is 10 mm or less. On the other hand, from the viewpoint of making the organic fibers function as a skeleton and ensuring the compressive strength of the insulation material, it is preferable that the average fiber length is 0.5 mm or more.
　これら有機繊維も、無機粒子と同様に、上記した無機繊維により良好に保持される。 These organic fibers, like the inorganic particles, are well held by the inorganic fibers described above.
（製造方法）
　断熱材Ａ１０の形成材料は上記のとおりであるが、断熱材Ａ１０を製造するには、抄造法を行うことができる。すなわち、断熱材Ａ１０の形成材料である無機粒子や無機繊維、他の配合材料を水に分散させ、その分散液を脱水、成形、乾燥して製造する。 (Production method)
The materials for forming the thermal insulation material A10 are as described above, and a papermaking method can be used to manufacture the thermal insulation material A10. That is, the materials for forming the thermal insulation material A10, such as inorganic particles, inorganic fibers, and other compounding materials, are dispersed in water, and the dispersion is dehydrated, molded, and dried to manufacture the thermal insulation material A10.
　また、乾式法で製造することもできる。すなわち、断熱材Ａ１０の形成材料である無機粒子や無機繊維、他の配合材料を適当な混合機に投入し、十分に分散させ、プレス成形して製造する。 It can also be manufactured by a dry method. That is, the materials that make up the insulating material A10, such as inorganic particles, inorganic fibers, and other compounding materials, are put into an appropriate mixer, thoroughly dispersed, and press-molded to produce it.
＜無機シートＡ２０＞
　無機シートＡ２０として、無機繊維クロスや無機不織布を用いることができる。無機シートＡ２０の無機繊維には制限はなく、上記した断熱材Ａ１０に使用される無機繊維を用いることもできる。中でも、安価で、取扱性に優れ、高い耐熱性を有することなどから、シリカ繊維やアルミナ繊維、ガラス繊維及び金属繊維が好ましく、縫合のし易さから、シリカクロス及びアルミナクロスのうち少なくとも一種がより好ましい。 <Inorganic sheet A20>
As the inorganic sheet A20, an inorganic fiber cloth or an inorganic nonwoven fabric can be used. There is no limitation on the inorganic fiber of the inorganic sheet A20, and the inorganic fiber used in the above-mentioned heat insulating material A10 can also be used. Among them, silica fiber, alumina fiber, glass fiber, and metal fiber are preferable because they are inexpensive, easy to handle, and have high heat resistance, and at least one of silica cloth and alumina cloth is more preferable because they are easy to sew.
　無機繊維クロスは、これら無機繊維を布状に織ったものであれば、繊維径など形状的な制限はない。また、無機不織布は、これら無繊繊維の抄造体である。なお、熱暴走を起こした電池セルからの飛散物の衝突を防止することを考慮すると、目開きは小さい方が好ましい。無機不織布の目開きは、無機不織布を光学顕微鏡にセットして、モニターにその画像を映し出し、画像上で大きさを読み取ることができる。 As long as inorganic fiber cloth is made by weaving these inorganic fibers into a cloth, there are no restrictions on the shape, such as fiber diameter. Inorganic nonwoven fabric is a paper-made product made from these nonwoven fibers. Considering the need to prevent collisions with debris from a battery cell experiencing thermal runaway, it is preferable for the mesh size to be small. The mesh size of inorganic nonwoven fabric can be determined by placing the inorganic nonwoven fabric under an optical microscope and projecting the image on a monitor, and then reading the size on the image.
＜縫糸Ａ３０＞
　縫糸Ａ３０を用いて、断熱材Ａ１０と無機シートＡ２０とを縫合する。縫糸Ａ３０は、無機シートＡ２０の無機繊維よりも融点が低く、図１に示すように、縫い目Ａ３０ａが無機シートＡ２０の電池セルなどの熱源側の表面Ａ２０ａに露出している。縫糸Ａ３０は、無機シートＡ２０の無機繊維よりも融点が低いため、熱暴走を起こした電池セル等の熱源からの高熱や火炎を受けた際に、縫糸Ａ３０の縫い目Ａ３０ａが溶融する。なお、熱源側（図１中、下側）の被覆材Ａ４０は高熱や火炎により焼失する。 <Sewing thread A30>
The insulating material A10 and the inorganic sheet A20 are sewn together using sewing thread A30. The sewing thread A30 has a lower melting point than the inorganic fibers of the inorganic sheet A20, and as shown in Fig. 1, the seam A30a is exposed on the surface A20a of the inorganic sheet A20 on the heat source side, such as a battery cell. Since the sewing thread A30 has a lower melting point than the inorganic fibers of the inorganic sheet A20, the seam A30a of the sewing thread A30 melts when exposed to high heat or flame from a heat source, such as a battery cell that has experienced thermal runaway. Note that the covering material A40 on the heat source side (lower side in Fig. 1) is burned away by the high heat or flame.
　そして、縫糸Ａ３０の縫い目Ａ３０ａに由来する融液が、無機シートＡ２０の表面Ａ２０ａ側の表層近傍や内部の無機繊維間に流入し、無機繊維と融着したまま凝固する。そして、図中に波線で示すように、凝固物Ａ３５がストッパーとして作用し、断熱材Ａ１０と無機シートＡ２０との積層構造を維持する。 Then, the molten liquid originating from the seams A30a of the sewing thread A30 flows into the vicinity of the surface layer on the surface A20a side of the inorganic sheet A20 and between the inorganic fibers inside, and solidifies while fused to the inorganic fibers. Then, as shown by the wavy line in the figure, the solidified matter A35 acts as a stopper, maintaining the laminated structure of the insulating material A10 and the inorganic sheet A20.
　縫糸Ａ３０の縫い目Ａ３０ａに由来する融液が、無機シートＡ２０の表面Ａ２０ａ側の表層近傍や内部の無機繊維間に流入しやすいようにするには、縫糸Ａ３０を無機シートＡ２０の目開きよりも細くする。すなわち、無機繊維クロスでは目開きがほぼ一定であり、それよりも細い縫糸Ａ３０を用い、また、無機不織布では目開きが一定ではないものの、最小目開きよりも細い縫糸Ａ３０を用いる。また、最小目開きよりも細い縫糸Ａ３０を用いることによって断熱材Ａ１０と無機シートＡ２０を縫合する際に無機シートＡ２０へのダメージが少なくなる。なお、縫糸Ａ３０の太さの下限は、断熱材Ａ１０と無機シートＡ２０との縫合状態を維持できる範囲であれば、制限はない。 To allow the molten liquid originating from the stitches A30a of the sewing thread A30 to easily flow into the vicinity of the surface layer on the surface A20a side of the inorganic sheet A20 and between the inorganic fibers inside, the sewing thread A30 is made thinner than the mesh size of the inorganic sheet A20. That is, in inorganic fiber cloth, the mesh size is almost constant, and a sewing thread A30 thinner than that is used, and in inorganic nonwoven fabric, the mesh size is not constant, but a sewing thread A30 thinner than the minimum mesh size is used. Also, by using a sewing thread A30 thinner than the minimum mesh size, damage to the inorganic sheet A20 is reduced when sewing the insulating material A10 and the inorganic sheet A20 together. There is no lower limit on the thickness of the sewing thread A30, so long as it is within a range in which the sewn state between the insulating material A10 and the inorganic sheet A20 can be maintained.
　縫糸Ａ３０の材質としては、無機シートＡ２０の無機繊維よりも低融点であれば無機繊維でも有機繊維でもよく、無機繊維及び有機繊維のうち少なくとも一種であることが好ましい。なお、縫糸Ａ３０も耐熱性を有することが好ましいことから、ガラス繊維、シリカ繊維、チタン酸カリウム繊維、ケイ酸カルシウム繊維、アラミド繊維及びナイロン繊維のうち少なくとも一種から選ばれることが好ましい。また、炭化するなどして、それ以上燃焼しない「自己消化性」を有する繊維を用いることも好ましい。 The material for the sewing thread A30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet A20, and is preferably at least one of inorganic and organic fibers. Since the sewing thread A30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that are "self-extinguishing" and do not burn any more after being carbonized, etc.
＜その他の層＞
（被覆材Ａ４０）
　断熱材Ａ１０は無機粒子や短繊維を含むため、これらの粉落ちを防止したり、湿気や電池セルから液漏れした電解液の吸収を防止するために、図１に示すように、積層体の全体を被覆材Ａ４０で包囲してもよい。被覆材Ａ４０としては、各種の樹脂フィルムや金属箔などを使用できるが、密着性の高さから、ＰＶＣ（ポリ塩化ビニル）やＰＳ（ポリスチレン）、ＰＥＴ（ポリエチレンテレフタレート）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）等の熱収縮フィルムが好ましい。 <Other demographics>
(Coating material A40)
Since the insulating material A10 contains inorganic particles and short fibers, in order to prevent these from falling off and to prevent the absorption of moisture and electrolyte leaked from the battery cells, the entire laminate may be surrounded by a covering material A40 as shown in Fig. 1. As the covering material A40, various resin films and metal foils can be used, but heat-shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
（接着剤層Ａ５０）
　断熱材Ａ１０と無機シートＡ２０とをより強固に接合するために、図１に示すように、接着剤層Ａ５０を介在させることもできる。 (Adhesive layer A50)
In order to bond the heat insulating material A10 and the inorganic sheet A20 more firmly, an adhesive layer A50 may be interposed between them as shown in FIG.
　また、接着剤層Ａ５０は、図２に示すように、熱暴走を起こした電池セルからの高熱や火炎を受けた際に揮発し、空気層Ａ６０が新たに形成される。その結果、空気層Ａ６０による断熱効果が加味されるため、熱伝達抑制シートＡ１は断熱性能により優れたものとなる。例えば、図３に示す電池モジュールＡ１００では、電池ケースＡ１２０の天蓋に、熱伝達抑制シートＡ１の熱源とは反対側（図中の上側）の被覆材Ａ４０を接着して使用される。そして、接着剤層Ａ５０が焼失すると、無機シートＡ２０は断熱材Ａ１０から剥離し、自重により垂れ下がるが、凝固物Ａ３５により無機シートＡ２０は垂れ下がった状態を維持し、空気層Ａ６０が形成されて熱伝達抑制シートＡ１としての断熱性能が高まり、電池ケースＡ１２０の天蓋への延焼を防ぐことができる。 Also, as shown in FIG. 2, the adhesive layer A50 evaporates when exposed to high heat or flames from a battery cell that has gone into thermal runaway, and a new air layer A60 is formed. As a result, the heat-insulating effect of the air layer A60 is added, and the heat-transfer suppression sheet A1 has better heat-insulating performance. For example, in the battery module A100 shown in FIG. 3, the covering material A40 is attached to the lid of the battery case A120 on the opposite side of the heat source of the heat-transfer suppression sheet A1 (upper side in the figure). When the adhesive layer A50 is burned, the inorganic sheet A20 peels off from the insulating material A10 and sags under its own weight, but the inorganic sheet A20 maintains its sagging state due to the solidified matter A35, and the air layer A60 is formed, improving the heat-insulating performance of the heat-transfer suppression sheet A1 and preventing the spread of fire to the lid of the battery case A120.
［電池モジュール］
　図３に示すように、電池モジュールＡ１００は、複数の電池セルＡ１１０を、電池ケースＡ１２０に収容したものである。そして、本実施形態では、上記の熱伝達抑制シートＡ１を、無機シートＡ２０が電池セルＡ１１０と対向する面となるように、電池ケースＡ１２０の天蓋や側壁、底壁の少なくとも１つ（同図ではこれら全面）に配設されている。あるいは、電池セル（蓄電池）Ａ１１０間に配設してもよい。 [Battery module]
3, the battery module A100 contains a plurality of battery cells A110 housed in a battery case A120. In this embodiment, the heat-transfer-suppressing sheet A1 is disposed on at least one of the top, side wall, and bottom wall of the battery case A120 (on the entire surfaces of these in the figure) so that the inorganic sheet A20 faces the battery cells A110. Alternatively, the heat-transfer-suppressing sheet A1 may be disposed between the battery cells (storage batteries) A110.
　続いて、上記「第２発明群」に係る「第２実施形態」について説明する。 Next, we will explain the "second embodiment" related to the above-mentioned "second invention group."
［熱伝達抑制シート］
　図４に分解断面図で示すように、本実施形態の熱伝達抑制シートＢ１は、断熱材Ｂ１０と、無機シートＢ２０とを有する積層体を、縫糸Ｂ３０で縫合して一体化したものである。 [Heat transfer suppression sheet]
As shown in the exploded cross-sectional view of FIG. 4, the heat-transfer-suppressing sheet B1 of this embodiment is formed by sewing together a laminate having a heat insulating material B10 and an inorganic sheet B20 with sewing thread B30.
　なお、断熱材Ｂ１０及び無機シートＢ２０については、上記した第１実施形態において説明したものと同様のものを適宜用いることができるため、詳述を省略する。 Note that the insulating material B10 and inorganic sheet B20 may be similar to those described in the first embodiment above, and therefore detailed description will be omitted.
＜縫糸Ｂ３０＞
　縫糸Ｂ３０を用いて、断熱材Ｂ１０と無機シートＢ２０とを縫合する。縫糸Ｂ３０は、無機シートＢ２０の無機繊維よりも融点が低く、無機シートＢ２０の目開きよりも太い繊維からなる。すなわち、無機繊維クロスでは目開きがほぼ一定であり、それよりも太い縫糸Ｂ３０を用い、無機不織布では目開きが一定ではないものの、最大目開きよりも太い縫糸Ｂ３０を用いる。無機シートＢ２０の無機繊維は柔軟で、容易に変形できるため、縫糸Ｂ３０が無機シートＢ２０の目開きよりも少々太くても、縫合に支障は無い。なお、縫糸Ｂ３０の太さの上限は、縫合できる範囲であれば、制限はないが、無機繊維クロス又は無機不織布を構成する繊維を破壊しない程度の太さであることが好ましい。 <Sewing thread B30>
The thermal insulation material B10 and the inorganic sheet B20 are sewn together using the sewing thread B30. The sewing thread B30 has a lower melting point than the inorganic fibers of the inorganic sheet B20 and is made of fibers that are thicker than the mesh size of the inorganic sheet B20. That is, the mesh size of the inorganic fiber cloth is almost constant, and a sewing thread B30 that is thicker than the mesh size is used, while the mesh size of the inorganic nonwoven fabric is not constant, but a sewing thread B30 that is thicker than the maximum mesh size is used. Since the inorganic fibers of the inorganic sheet B20 are flexible and can be easily deformed, there is no problem with sewing even if the sewing thread B30 is slightly thicker than the mesh size of the inorganic sheet B20. There is no upper limit on the thickness of the sewing thread B30 as long as it can be sewn, but it is preferable that the thickness be such that the fibers constituting the inorganic fiber cloth or inorganic nonwoven fabric are not destroyed.
　図４に示すように、縫糸Ｂ３０の縫い目Ｂ３０ａが、無機シートＢ２０の電池セルなどの熱源側の表面Ｂ２０ａに露出している。縫糸Ｂ３０は、無機シートＢ２０の無機繊維よりも融点が低いため、熱暴走を起こした電池セル等の熱源からの高熱や火炎を受けた際に、縫糸Ｂ３０の縫い目Ｂ３０ａが溶融する。なお、熱源側（図４中、下側）の被覆材Ｂ４０は高熱や火炎により焼失する。また、縫糸Ｂ３０は無機シートＢ２０の目開きよりも太いため、溶融後に凝固した際に、図５に示すように、凝固物Ｂ３５が無機シートＢ２０の目開きよりも大きな塊（略球状の塊）となって無機シートＢ２０の表面Ｂ２０ａから露出して点在する。そして、凝固物Ｂ３５が、ストッパーとして作用し、断熱材Ｂ１０と無機シートＢ２０との積層構造を維持する。 As shown in FIG. 4, the seams B30a of the sewing thread B30 are exposed on the surface B20a of the inorganic sheet B20 on the heat source side, such as a battery cell. Since the sewing thread B30 has a lower melting point than the inorganic fibers of the inorganic sheet B20, the seams B30a of the sewing thread B30 melt when exposed to high heat or flames from a heat source, such as a battery cell that has undergone thermal runaway. The covering material B40 on the heat source side (lower side in FIG. 4) is burned away by the high heat or flames. In addition, since the sewing thread B30 is thicker than the mesh size of the inorganic sheet B20, when it melts and solidifies, as shown in FIG. 5, the solidified matter B35 becomes a mass (approximately spherical mass) larger than the mesh size of the inorganic sheet B20 and is exposed and scattered on the surface B20a of the inorganic sheet B20. The solidified matter B35 acts as a stopper to maintain the laminated structure of the insulating material B10 and the inorganic sheet B20.
　なお、図５では、凝固物Ｂ３５が球状になっているが、熱源である電池セルが火炎を発するような場合は、高熱とともに爆風が発生することがあるため、縫糸Ｂ３０の縫い目Ｂ３０ａの溶融液は強い風圧を受け、凝固物Ｂ３５は球状とはならずに扁平するなどして不定形となる。また、縫糸Ｂ３０の縫い目Ｂ３０ａが長いほど、溶融液の量が多くなり、凝固物Ｂ３５も大きくなる。そのため、縫糸Ｂ３０の縫い目Ｂ３０ａの長さで凝固物Ｂ３５の大きさを制御することもできる。 In FIG. 5, the solidified matter B35 is spherical, but if the battery cell, which is the heat source, emits a flame, an explosion may occur along with the high heat, and the molten liquid in the stitch B30a of the sewing thread B30 will be subjected to strong wind pressure, causing the solidified matter B35 to become irregular, such as flattening rather than becoming spherical. Also, the longer the stitch B30a of the sewing thread B30, the greater the amount of molten liquid and the larger the solidified matter B35. Therefore, the size of the solidified matter B35 can be controlled by the length of the stitch B30a of the sewing thread B30.
　縫糸Ｂ３０の材質としては、無機シートＢ２０の無機繊維よりも低融点であれば無機繊維でも有機繊維でもよく、無機繊維及び有機繊維のうち少なくとも一種であることが好ましい。なお、縫糸Ｂ３０も耐熱性を有することが好ましいことから、ガラス繊維、シリカ繊維、チタン酸カリウム繊維、ケイ酸カルシウム繊維、アラミド繊維及びナイロン繊維のうち少なくとも一種から選ばれることが好ましい。また、炭化するなどして、それ以上燃焼しない「自己消化性」を有する繊維を用いることも好ましい。 The material of the sewing thread B30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet B20, and is preferably at least one of inorganic fiber and organic fiber. Since the sewing thread B30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that are "self-extinguishing" and do not burn any more after being carbonized, etc.
＜その他の層＞
（被覆材Ｂ４０）
　断熱材Ｂ１０は無機粒子や短繊維を含むため、これらの粉落ちを防止したり、湿気や電池セルから液漏れした電解液の吸収を防止するために、図４に示すように、積層体の全体を被覆材Ｂ４０で包囲してもよい。被覆材Ｂ４０としては、各種の樹脂フィルムや金属箔などを使用できるが、密着性の高さから、ＰＶＣ（ポリ塩化ビニル）やＰＳ（ポリスチレン）、ＰＥＴ（ポリエチレンテレフタレート）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）等の熱収縮フィルムが好ましい。 <Other demographics>
(Coating material B40)
Since the insulating material B10 contains inorganic particles and short fibers, in order to prevent these from falling off and to prevent the absorption of moisture and electrolyte leaked from the battery cells, the entire laminate may be surrounded by a covering material B40 as shown in Fig. 4. As the covering material B40, various resin films and metal foils can be used, but heat-shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
（接着剤層Ｂ５０）
　断熱材Ｂ１０と無機シートＢ２０とをより強固に接合するために、図４に示すように、接着剤層Ｂ５０を介在させることもできる。 (Adhesive layer B50)
In order to bond the heat insulating material B10 and the inorganic sheet B20 more firmly, an adhesive layer B50 may be interposed between them as shown in FIG.
　また、接着剤層Ｂ５０は、図５に示すように、熱暴走を起こした電池セルからの高熱や火炎を受けた際に揮発し、空気層Ｂ６０が新たに形成される。その結果、空気層Ｂ６０による断熱効果が加味されるため、熱伝達抑制シートＢ１は断熱性能により優れたものとなる。例えば、図７に示す電池モジュールＢ１００では、電池ケースＢ１２０の天蓋に、熱伝達抑制シートＢ１の熱源とは反対側（図中の上側）の被覆材Ｂ４０を接着して使用される。そして、接着剤層Ｂ５０が焼失すると、無機シートＢ２０は断熱材Ｂ１０から剥離し、自重により垂れ下がるが、凝固物Ｂ３５により無機シートＢ２０は垂れ下がった状態を維持し、空気層Ｂ６０が形成されて熱伝達抑制シートＢ１としての断熱性能が高まり、電池ケースＢ１２０の天蓋への延焼を防ぐことができる。 Also, as shown in FIG. 5, when the adhesive layer B50 is exposed to high heat or flames from a battery cell that has gone into thermal runaway, it evaporates, and a new air layer B60 is formed. As a result, the heat-insulating effect of the air layer B60 is added, and the heat-transfer suppression sheet B1 has better heat-insulating performance. For example, in the battery module B100 shown in FIG. 7, the covering material B40 is attached to the lid of the battery case B120 on the opposite side of the heat source of the heat-transfer suppression sheet B1 (upper side in the figure). When the adhesive layer B50 is burned, the inorganic sheet B20 peels off from the insulating material B10 and sags under its own weight, but the inorganic sheet B20 maintains its sagging state due to the solidified matter B35, and the air layer B60 is formed, improving the heat-insulating performance of the heat-transfer suppression sheet B1 and preventing the spread of fire to the lid of the battery case B120.
（実施例）
　熱伝達抑制シートＢ１として、シリカ粒子を含む断熱材Ｂ１０と、無機シートＢ２０としてシリカクロスとを積層し、縫糸Ｂ３０としてガラス繊維を用いて縫合したものを用意した。そして、バーナーから約１０００℃の火炎をシリカクロスの表面に当て、自然冷却した後にシリカクロスの表面を観察した。 (Example)
A heat transfer-suppressing sheet B1 was prepared by laminating a heat insulating material B10 containing silica particles and a silica cloth as an inorganic sheet B20, and sewing them together using glass fiber as sewing thread B30. A flame of about 1000° C. was then applied from a burner to the surface of the silica cloth, and the surface of the silica cloth was observed after it was allowed to cool naturally.
　図６は、火炎を当てた後のシリカクロスの表面を撮影した図面代用写真であるが、ガラス繊維の縫目に由来し、シリカクロスの目開きよりも大きな略球状の凝固物Ｂ３５が在しているのがわかる。なお、図６中の左上の白い部分が、火炎を当てた部分であり、凝固物Ｂ３５は火炎を当てた部分では略全面にわたり点在しており、火炎を当てた部分の外側にも幾つか点在している。 Figure 6 is a photograph taken of the surface of the silica cloth after it was hit by flame, and it can be seen that there are roughly spherical coagulated masses B35 that originate from the seams of the glass fibers and are larger than the mesh size of the silica cloth. The white area in the upper left of Figure 6 is the area that was hit by flame, and coagulated masses B35 are scattered over almost the entire surface of the area that was hit by flame, with some scattered outside the area that was hit by flame.
［電池モジュール］
　図７に示すように、電池モジュールＢ１００は、複数の電池セルＢ１１０を、電池ケースＢ１２０に収容したものである。そして、本実施形態では、上記の熱伝達抑制シートＢ１を、無機シートＢ２０が電池セルＢ１１０と対向する面となるように、電池ケースＢ１２０の天蓋や側壁、底壁の少なくとも１つ（同図ではこれら全面）に配設されている。あるいは、電池セル（蓄電池）Ｂ１１０間に配設してもよい。 [Battery module]
7, the battery module B100 contains a plurality of battery cells B110 housed in a battery case B120. In this embodiment, the heat-transfer-suppressing sheet B1 is disposed on at least one of the top, side wall, and bottom wall of the battery case B120 (on the entire surfaces of these in the figure) so that the inorganic sheet B20 faces the battery cells B110. Alternatively, the heat-transfer-suppressing sheet B1 may be disposed between the battery cells (storage batteries) B110.
　続いて、上記「第３発明群」に係る「第３実施形態」について説明する。 Next, we will explain the "third embodiment" related to the above-mentioned "third invention group."
［熱伝達抑制シート］
　図８に示すように、本実施形態の熱伝達抑制シートＣ１は、断熱材Ｃ１０と、無機シートＣ２０とを有する積層体を縫糸Ｃ３０で縫合して一体化し、更に、図９に示すように、無機シートＣ２０の表面Ｃ２０ａから露出して、縫糸Ｃ３０の溶融物の凝固物Ｃ３５が存在したもの、又は、図１０に示すように、縫糸Ｃ３０の溶融物が、無機シートＣ２０の表面Ｃ２０ａ側の表層近傍や内部の無機繊維間に流入し、無機繊維と融着したまま凝固した凝固物Ｃ３５が存在したものである。 [Heat transfer suppression sheet]
As shown in Figure 8, the heat transfer-inhibiting sheet C1 of this embodiment is formed by sewing together a laminate having an insulating material C10 and an inorganic sheet C20 with a sewing thread C30, and further, as shown in Figure 9, a solidified material C35 of the molten sewing thread C30 is exposed from the surface C20a of the inorganic sheet C20, or, as shown in Figure 10, the molten sewing thread C30 has flowed into the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20 or between the inorganic fibers inside, and has solidified while remaining fused to the inorganic fibers, forming a solidified material C35.
　なお、本発明でいう「無機シートの表面部」とは、無機シートＣ２０の表面Ｃ２０ａそのもの、及び無機シートＣ２０の表面Ｃ２０ａ側の表層近傍（具体的には、無機シートＣ２０の表面Ｃ２０ａ側から見て、無機シートＣ２０の半分の厚さまでの範囲、好ましくは、無機シートＣ２０の表面Ｃ２０ａ側から見て、無機シートＣ２０の１／３の厚さまでの範囲）を含むものとする。 In addition, the "surface portion of the inorganic sheet" in the present invention includes the surface C20a of the inorganic sheet C20 itself, and the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20 (specifically, the range up to half the thickness of the inorganic sheet C20 when viewed from the surface C20a side of the inorganic sheet C20, preferably the range up to 1/3 the thickness of the inorganic sheet C20 when viewed from the surface C20a side of the inorganic sheet C20).
　なお、断熱材Ｃ１０及び無機シートＣ２０については、上記した第１実施形態において説明したものと同様のものを適宜用いることができるため、詳述を省略する。 Note that the insulating material C10 and inorganic sheet C20 may be similar to those described in the first embodiment above, and therefore detailed description will be omitted.
＜縫糸Ｃ３０＞
　縫糸Ｃ３０を用いて、断熱材Ｃ１０と無機シートＣ２０とを縫合する。縫糸Ｃ３０は、無機シートＣ２０の無機繊維よりも融点が低い繊維を用いる。
　縫糸Ｃ３０の材質としては、無機シートＣ２０の無機繊維よりも低融点であれば無機繊維でも有機繊維でもよく、無機繊維及び有機繊維のうち少なくとも一種であることが好ましい。なお、縫糸Ｃ３０も耐熱性を有することが好ましいことから、ガラス繊維、シリカ繊維、チタン酸カリウム繊維、ケイ酸カルシウム繊維、アラミド繊維及びナイロン繊維のうち少なくとも一種から選ばれることが好ましい。また、炭化するなどして、それ以上燃焼しない「自己消化性」を有する繊維を用いることも好ましい。 <Sewing thread C30>
The heat insulating material C10 and the inorganic sheet C20 are sewn together using a sewing thread C30. The sewing thread C30 uses fibers having a lower melting point than the inorganic fibers of the inorganic sheet C20.
The material of the sewing thread C30 may be inorganic or organic fiber as long as it has a lower melting point than the inorganic fiber of the inorganic sheet C20, and is preferably at least one of inorganic fiber and organic fiber. Since the sewing thread C30 is also preferably heat resistant, it is preferably selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber. It is also preferable to use fibers that have "self-extinguishing properties" that do not burn any more after being carbonized, etc.
　なお、縫糸Ｃ３０の太さは、縫合に支障のないものを選ぶことができる。後述する製造方法に示すように、断熱材Ｃ１０と無機シートＣ２０とを縫糸Ｃ３０で縫合した積層体の無機シートＣ２０の表面に、縫い糸Ｃ３０の融点以上の高熱を作用させることにより、熱伝達抑制シートＣ１が得られる。 The thickness of the sewing thread C30 can be selected so long as it does not interfere with sewing. As shown in the manufacturing method described below, the heat transfer suppression sheet C1 is obtained by applying high heat above the melting point of the sewing thread C30 to the surface of the inorganic sheet C20 of the laminate in which the insulating material C10 and the inorganic sheet C20 are sewn together with the sewing thread C30.
　その際、縫糸Ｃ３０として、無機シートＣ２０の目開きよりも太い繊維を用いると、図９に示すように、無機シートＣ２０の表面Ｃ２０ａから露出している縫糸Ｃ３０の縫い目Ｃ３０ａが、高熱を受けて溶融する。なお、熱源側（図９中、下側）の被覆材Ｃ４０に、高熱により焼失する。縫糸Ｃ３０は無機シートＣ２０の目開きよりも太いため、縫い目Ｃ３０ａが溶融後に凝固した際に、凝固物Ｃ３５が無機シートＣ２０の目開きよりも大きな塊（略球状の塊）となって無機シートＣ２０の表面Ｃ２０ａから露出して点在する。なお、図９では、凝固物Ｃ３５が球状になっているが、不定形であってもよい。また、縫糸Ｃ３０の縫い目Ｃ３０ａが長いほど、溶融液の量が多くなり、凝固物Ｃ３５も大きくなる。そのため、縫糸Ｃ３０の縫い目Ｃ３０ａの長さで凝固物Ｃ３５の大きさを制御することができる。 In this case, if a fiber thicker than the mesh size of the inorganic sheet C20 is used as the sewing thread C30, the seam C30a of the sewing thread C30 exposed from the surface C20a of the inorganic sheet C20 melts due to high heat, as shown in FIG. 9. The covering material C40 on the heat source side (lower side in FIG. 9) is burned away by the high heat. Since the sewing thread C30 is thicker than the mesh size of the inorganic sheet C20, when the seam C30a melts and solidifies, the solidified matter C35 becomes a mass (approximately spherical mass) larger than the mesh size of the inorganic sheet C20 and is exposed and scattered on the surface C20a of the inorganic sheet C20. In FIG. 9, the solidified matter C35 is spherical, but it may be of an indefinite shape. The longer the seam C30a of the sewing thread C30, the greater the amount of molten liquid and the larger the solidified matter C35. Therefore, the size of the coagulation C35 can be controlled by the length of the stitch C30a of the sewing thread C30.
　また、縫糸Ｃ３０として、無機シートＣ２０の最小目開きよりも細い繊維を用いると、図１０に示すように、縫糸Ｃ３０の縫い目Ｃ３０ａに由来する融液が、無機シートＣ２０の表面Ｃ２０ａ側の表層近傍における無機繊維間に流入し、無機繊維と融着したまま凝固し、図中に波線で示すような凝固物Ｃ３５となる。 Furthermore, if a fiber finer than the minimum mesh size of the inorganic sheet C20 is used as the sewing thread C30, as shown in FIG. 10, the molten liquid originating from the stitches C30a of the sewing thread C30 flows between the inorganic fibers near the surface layer on the surface C20a side of the inorganic sheet C20, and solidifies while fused to the inorganic fibers, forming a solidified mass C35 as shown by the wavy line in the figure.
　そして、凝固物Ｃ３５がストッパーとして作用し、断熱材Ｃ１０と無機シートＣ２０との積層構造を維持する。 The solidified material C35 acts as a stopper to maintain the laminated structure of the insulating material C10 and the inorganic sheet C20.
　なお、無機シートＣ２０が無機繊維クロスの場合は目開きがほぼ一定であり、それよりも太い縫糸Ｃ３０を用いる。また、無機不織布では目開きが一定ではないものの、最大目開きよりも太い縫糸Ｃ３０を用いる。無機繊維クロスや無機不織布の無機繊維は柔軟で、容易に変形できるため、縫糸Ｃ３０が無機繊維クロスや無機不織布の目開きよりも太くても、縫合に支障は無い。縫糸Ｃ３０の太さの上限は、断熱材Ｃ１０と無機シートＣ２０とを縫合できれる範囲であれば、制限はない。 When the inorganic sheet C20 is an inorganic fiber cloth, the mesh size is almost constant, and a sewing thread C30 thicker than that is used. Also, in the case of inorganic nonwoven fabric, the mesh size is not constant, but a sewing thread C30 thicker than the maximum mesh size is used. Since the inorganic fibers in inorganic fiber cloth and inorganic nonwoven fabric are flexible and can be easily deformed, there is no problem with sewing even if the sewing thread C30 is thicker than the mesh size of the inorganic fiber cloth or inorganic nonwoven fabric. There is no upper limit on the thickness of the sewing thread C30, so long as it is within the range in which the insulating material C10 and the inorganic sheet C20 can be sewn together.
　そして、無機不織布では、最小目開きよりも細い縫糸Ｃ３０を用いる。また、最小目開きよりも細い縫糸Ｃ３０を用いることによって断熱材Ｃ１０と無機シートＣ２０を縫合する際に無機シートＣ２０へのダメージが少なくなる。なお、縫糸Ｃ３０の太さの下限は、断熱材Ｃ１０と無機シートＣ２０とを縫合できる範囲であれば、制限はない。無機不織布の目開きは、無機不織布を光学顕微鏡にセットして、モニターにその画像を映し出し、画像上で大きさを読み取ることができる。 Then, for the inorganic nonwoven fabric, a sewing thread C30 finer than the minimum mesh size is used. Furthermore, by using a sewing thread C30 finer than the minimum mesh size, damage to the inorganic sheet C20 is reduced when sewing the insulating material C10 and the inorganic sheet C20 together. There is no lower limit to the thickness of the sewing thread C30, so long as it is within a range in which the insulating material C10 and the inorganic sheet C20 can be sewn together. The mesh size of the inorganic nonwoven fabric can be read from the image by placing the inorganic nonwoven fabric under an optical microscope and projecting the image on a monitor.
　ところで、熱伝達抑制シートＣ１が熱暴走を起こした電池セル等の熱源からの高熱や火炎を受けた際には、凝固物Ｃ３５は再溶融して、無機シートＣ２０の表面部（すなわち、無機シートＣ２０の表面Ｃ２０ａそのもの、及び無機シートＣ２０の表面Ｃ２０ａ側の表層近傍）にて、より広い領域に流動し、凝固する。そのため、ストッパーとしての機能がより高まる。 When the heat transfer suppression sheet C1 is exposed to high heat or flames from a heat source such as a battery cell that has experienced thermal runaway, the solidified matter C35 remelts and flows over a wider area on the surface of the inorganic sheet C20 (i.e., the surface C20a of the inorganic sheet C20 itself and in the vicinity of the surface layer on the surface C20a side of the inorganic sheet C20), where it solidifies. This further enhances its function as a stopper.
＜その他の層＞
（被覆材Ｃ４０）
　断熱材Ｃ１０は無機粒子や短繊維を含むため、これらの粉落ちを防止したり、湿気や電池セルから液漏れした電解液の吸収を防止するために、図８に示すように、積層体の全体を被覆材Ｃ４０で包囲してもよい。被覆材Ｃ４０としては、各種の樹脂フィルムや金属箔などを使用できるが、密着性の高さから、ＰＶＣ（ポリ塩化ビニル）やＰＳ（ポリスチレン）、ＰＥＴ（ポリエチレンテレフタレート）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）等の熱収縮フィルムが好ましい。 <Other demographics>
(Coating material C40)
Since the heat insulating material C10 contains inorganic particles and short fibers, in order to prevent these from falling off and to prevent the absorption of moisture and electrolyte leaked from the battery cells, the entire laminate may be surrounded by a covering material C40 as shown in Fig. 8. As the covering material C40, various resin films and metal foils can be used, but heat shrinkable films such as PVC (polyvinyl chloride), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are preferred because of their high adhesion.
（接着剤層Ｃ５０）
　断熱材Ｃ１０と無機シートＣ２０とをより強固に接合するために、図８に示すように、接着剤層Ｃ５０を介在させることもできる。 (Adhesive layer C50)
In order to bond the heat insulating material C10 and the inorganic sheet C20 more firmly, an adhesive layer C50 may be interposed between them as shown in FIG.
　また、接着剤層Ｃ５０は、高熱を作用させた際に揮発し、空気層Ｃ６０が新たに形成される。その結果、空気層Ｃ６０による断熱効果が加味されるため、熱伝達抑制シートＣ１は断熱性能により優れたものとなる。 In addition, the adhesive layer C50 volatilizes when exposed to high heat, and a new air layer C60 is formed. As a result, the heat-insulating effect of the air layer C60 is added, and the heat-transfer-suppressing sheet C1 has superior heat-insulating performance.
［熱伝達抑制シートの製造方法］
　熱伝達抑制シートＣ１を製造するには、まず、断熱材Ｃ１０と、無機シートＣ２０とを積層し、得られた積層体を縫糸Ｃ３０にて縫合する。次いで、無機シートＣ２０の表面Ｃ２０ａに対し、縫糸Ｃ３０の繊維の融点以上（例えば、８００℃以上、好ましくは９００℃以上、より好ましくは１０００℃以上、更に好ましくは１１００℃以上）の高熱を作用させて縫い目Ｃ３０を溶融する。上記高熱を作用させる方法としては、例えば、無機シートＣ２０の表面Ｃ２０ａにバーナーの火炎を当てたり、上記した温度相当に熱した熱板を押し当てればよい。そして、自然冷却して、縫い目Ｃ３０ａに由来する溶融液を硬化させるとよい。 [Method of manufacturing heat transfer-suppressing sheet]
To manufacture the heat transfer suppressing sheet C1, first, the heat insulating material C10 and the inorganic sheet C20 are laminated, and the resulting laminate is sewn with the sewing thread C30. Next, high heat equal to or higher than the melting point of the fibers of the sewing thread C30 (for example, 800°C or higher, preferably 900°C or higher, more preferably 1000°C or higher, and even more preferably 1100°C or higher) is applied to the surface C20a of the inorganic sheet C20 to melt the seam C30. As a method of applying the high heat, for example, a burner flame may be applied to the surface C20a of the inorganic sheet C20, or a hot plate heated to the above-mentioned temperature may be pressed against the surface C20a of the inorganic sheet C20. Then, the molten liquid derived from the seam C30a may be hardened by natural cooling.
（実施例）
　熱伝達抑制シートＣ１として、シリカ粒子を含む断熱材Ｃ１０と、無機シートＣ２０としてシリカクロスとを積層し、縫糸Ｃ３０としてガラス繊維を用いて縫合したものを用意した。そして、バーナーから約１０００℃の火炎をシリカクロスの表面に当て、自然冷却した後にシリカクロスの表面を観察した。 (Example)
A heat transfer-suppressing sheet C1 was prepared by laminating a heat insulating material C10 containing silica particles and a silica cloth as an inorganic sheet C20, and sewing them together using glass fiber as sewing thread C30. A flame of about 1000° C. was then applied from a burner to the surface of the silica cloth, and the surface of the silica cloth was observed after natural cooling.
　図１１は、火炎を当てた後のシリカクロスの表面を撮影した図面代用写真であるが、ガラス繊維の縫目に由来し、シリカクロスの目開きよりも大きいな球状の凝固物Ｃ３５が在しているのがわかる。なお、図１１中の左上の白い部分が火炎を当てた部分であり、凝固物Ｃ３５は火炎を当てた部分では略全面にわたり点在しており、火炎を当てた部分の外側にも幾つか点在している。 Figure 11 is a photograph taken of the surface of the silica cloth after it was hit by flame, and it can be seen that there are spherical coagulations C35 that originate from the seams of the glass fibers and are larger than the mesh size of the silica cloth. The white area in the upper left of Figure 11 is the part that was hit by flame, and coagulations C35 are scattered over almost the entire surface of the part that was hit by flame, with some scattered outside the part that was hit by flame.
［電池モジュール］
　図１２に示すように、電池モジュールＣ１００は、複数の電池セルＣ１１０を、電池ケースＣ１２０に収容したものである。そして、本実施形態では、上記の熱伝達抑制シートＣ１を、無機シートＣ２０が電池セルＣ１１０と対向する面となるように、電池ケースＣ１２０の天蓋や側壁、底壁の少なくとも１つ（同図ではこれら全面）に配設されている。あるいは、電池セル（蓄電池）Ｃ１１０間に配設してもよい。 [Battery module]
12, the battery module C100 contains a plurality of battery cells C110 housed in a battery case C120. In this embodiment, the heat transfer suppressing sheet C1 is disposed on at least one of the top, side wall, and bottom wall of the battery case C120 (on the entire surfaces of these in the figure) so that the inorganic sheet C20 faces the battery cells C110. Alternatively, the heat transfer suppressing sheet C1 may be disposed between the battery cells (storage batteries) C110.
　以上、図面を参照しながら各種の実施の形態について説明したが、本発明はかかる例に限定されないことは言うまでもない。当業者であれば、特許請求の範囲に記載された範疇内において、各種の変更例又は修正例に想到し得ることは明らかであり、それらについても当然に本発明の技術的範囲に属するものと了解される。また、発明の趣旨を逸脱しない範囲において、上記実施の形態における各構成要素を任意に組み合わせてもよい。 Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components in the above embodiments may be combined in any manner as long as it does not deviate from the spirit of the invention.
　なお、本出願は、２０２３年３月２９日出願の日本特許出願（特願２０２３－０５３７７９）、２０２３年３月２９日出願の日本特許出願（特願２０２３－０５３７８０）及び２０２３年３月２９日出願の日本特許出願（特願２０２３－０５３７８４）に基づくものであり、その内容は本出願の中に参照として援用される。 This application is based on Japanese patent applications filed on March 29, 2023 (Patent Application No. 2023-053779), March 29, 2023 (Patent Application No. 2023-053780), and March 29, 2023 (Patent Application No. 2023-053784), the contents of which are incorporated by reference into this application.
Ａ１、Ｂ１、Ｃ１　熱伝達抑制シート
Ａ１０、Ｂ１０、Ｃ１０　断熱材
Ａ２０、Ｂ２０、Ｃ２０　無機シート（無機繊維クロス又は無機不織布）
Ａ２０ａ、Ｂ２０ａ、Ｃ２０ａ　表面
Ａ３０、Ｂ３０、Ｃ３０　縫糸
Ａ３０ａ、Ｂ３０ａ、Ｃ３０ａ　縫い目
Ａ３５、Ｂ３５、Ｃ３５　凝固物
Ａ４０、Ｂ４０、Ｃ４０　被覆材
Ａ５０、Ｂ５０、Ｃ５０　接着剤層
Ａ６０、Ｂ６０、Ｃ６０　空気層
Ａ１００、Ｂ１００、Ｃ１００　電池モジュール
Ａ１１０、Ｂ１１０、Ｃ１１０　電池セル（蓄電池）
Ａ１２０、Ｂ１２０、Ｃ１２０　電池ケース A1, B1, C1 Heat transfer suppression sheet A10, B10, C10 Heat insulating material A20, B20, C20 Inorganic sheet (inorganic fiber cloth or inorganic nonwoven fabric)
A20a, B20a, C20a Surface A30, B30, C30 Sewing thread A30a, B30a, C30a Stitch A35, B35, C35 Coagulated material A40, B40, C40 Covering material A50, B50, C50 Adhesive layer A60, B60, C60 Air layer A100, B100, C100 Battery module A110, B110, C110 Battery cell (storage battery)
A120, B120, C120 Battery Case

Claims (16)

  1. 　断熱材と、無機シートとを含む積層体が、前記無機シートの無機繊維よりも融点が低い縫糸で縫合されている、熱伝達抑制シート。 A heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with sewing thread having a melting point lower than that of the inorganic fibers of the inorganic sheet.
  2. 　前記縫糸は、前記無機シートの目開きよりも細いことを特徴とする請求項１に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 1, characterized in that the sewing thread is finer than the mesh size of the inorganic sheet.
  3. 　前記無機シートが無機繊維クロス又は無機不織布であり、かつ、前記無機シートが前記無機繊維クロスの場合には、前記縫糸が前記無機繊維クロスの目開きよりも細く、また、前記無機シートが前記無機不織布の場合には、前記無機不織布の最小目開きよりも細いことを特徴とする請求項２に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 2, characterized in that the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric, and when the inorganic sheet is the inorganic fiber cloth, the sewing thread is finer than the mesh size of the inorganic fiber cloth, and when the inorganic sheet is the inorganic nonwoven fabric, the sewing thread is finer than the minimum mesh size of the inorganic nonwoven fabric.
  4. 　断熱材と、無機シートとを含む積層体が、前記無機シートの無機繊維よりも融点が低く、前記無機シートの目開きよりも太い縫糸で縫合されている、熱伝達抑制シート。 A heat transfer suppression sheet in which a laminate containing a heat insulating material and an inorganic sheet is sewn together with a sewing thread that has a lower melting point than the inorganic fibers of the inorganic sheet and is thicker than the mesh openings of the inorganic sheet.
  5. 　前記無機シートが無機繊維クロス又は無機不織布であり、かつ、前記無機シートが前記無機繊維クロスの場合には、前記縫糸が前記無機繊維クロスの目開きよりも太く、また、前記無機シートが前記無機不織布の場合には、前記無機不織布の最大目開きよりも太いことを特徴とする請求項４に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 4, characterized in that the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric, and when the inorganic sheet is the inorganic fiber cloth, the sewing thread is thicker than the mesh size of the inorganic fiber cloth, and when the inorganic sheet is the inorganic nonwoven fabric, the sewing thread is thicker than the maximum mesh size of the inorganic nonwoven fabric.
  6. 　断熱材と、無機シートとが、有機質又は無機質の縫糸にて縫合された積層体の前記無機シートの表面部に、前記縫糸の溶融物の凝固物が存在する、熱伝達抑制シート。 A heat transfer suppression sheet in which a thermal insulation material and an inorganic sheet are sewn together with organic or inorganic sewing thread, and a solidified product of the molten sewing thread is present on the surface of the inorganic sheet of the laminate.
  7. 　前記無機シートは、無機繊維クロス又は無機不織布であることを特徴とする請求項６に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 6, characterized in that the inorganic sheet is an inorganic fiber cloth or an inorganic nonwoven fabric.
  8. 　前記凝固物は、前記無機シートの表面部に点在していることを特徴とする請求項６に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 6, characterized in that the solidified matter is scattered on the surface of the inorganic sheet.
  9. 　前記断熱材は、無機粒子を含むことを特徴とする請求項１～８のいずれか１項に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to any one of claims 1 to 8, characterized in that the insulating material contains inorganic particles.
  10. 　前記無機粒子は、シリカ粒子、アルミナ粒子、チタニア粒子、ジルコニア粒子及び水酸化アルミニウム粒子のうち少なくとも一種から選ばれることを特徴とする請求項９に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 9, characterized in that the inorganic particles are selected from at least one of silica particles, alumina particles, titania particles, zirconia particles, and aluminum hydroxide particles.
  11. 　前記縫糸は、無機繊維及び有機繊維のうち少なくとも一種であることを特徴とする請求項１～１０のいずれか１項に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to any one of claims 1 to 10, characterized in that the sewing thread is at least one of inorganic fibers and organic fibers.
  12. 　前記縫糸は、ガラス繊維、シリカ繊維、チタン酸カリウム繊維、ケイ酸カルシウム繊維、アラミド繊維及びナイロン繊維のうち少なくとも一種から選ばれることを特徴とする請求項１１に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to claim 11, characterized in that the sewing thread is selected from at least one of glass fiber, silica fiber, potassium titanate fiber, calcium silicate fiber, aramid fiber, and nylon fiber.
  13. 　前記無機シートは、シリカクロス及びアルミナクロスのうち少なくとも一種であることを特徴とする請求項１～１２のいずれか１項に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to any one of claims 1 to 12, characterized in that the inorganic sheet is at least one of silica cloth and alumina cloth.
  14. 　前記断熱材と、前記無機シートとが、接着剤層を介して接合されていることを特徴とする請求項１～１３のいずれか１項に記載の熱伝達抑制シート。 The heat transfer suppression sheet according to any one of claims 1 to 13, characterized in that the insulating material and the inorganic sheet are bonded via an adhesive layer.
  15. 　請求項６～８のいずれか１項に記載の熱伝達抑制シートの製造方法であって、
    　断熱材と、無機シートとを含む積層体を、有機質又は無機質の縫糸にて縫合する工程と、
    　縫合された前記積層体の前記無機シートの表面に、前記縫糸の融点以上の高熱を作用させて前記縫糸を溶融する工程と、
    　前記縫糸の溶融物を硬化させる工程と、
    を有する、熱伝達抑制シートの製造方法。     A method for producing the heat transfer-suppressing sheet according to any one of claims 6 to 8, comprising the steps of:
    A step of sewing a laminate including a thermal insulating material and an inorganic sheet with an organic or inorganic sewing thread;
    a step of applying high heat equal to or higher than the melting point of the sewing thread to a surface of the inorganic sheet of the sewn laminate to melt the sewing thread;
    hardening the melt of the sewing thread;
    The heat transfer-suppressing sheet according to the present invention comprises:
  16. 　蓄電池を電池ケースに収容し、かつ、前記電池ケースの天蓋、側壁、底壁、並びに前記蓄電池の間の少なくとも１つに、請求項１～１４のいずれか１項に記載の熱伝達抑制シートを配設した、電池モジュール。 A battery module in which a storage battery is housed in a battery case, and a heat transfer suppression sheet according to any one of claims 1 to 14 is disposed on at least one of the lid, side walls, and bottom walls of the battery case, and between the storage batteries.
PCT/JP2024/012288 2023-03-29 2024-03-27 Heat transfer suppressing sheet, method for manufacturing same, and battery module WO2024204375A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2023-053784 2023-03-29
JP2023-053779 2023-03-29
JP2023053784A JP2024141910A (en) 2023-03-29 2023-03-29 Heat transfer suppression sheet, manufacturing method thereof, and battery module
JP2023-053780 2023-03-29
JP2023053779A JP2024141906A (en) 2023-03-29 2023-03-29 Heat transfer suppression sheet and battery module
JP2023053780A JP2024141907A (en) 2023-03-29 2023-03-29 Heat transfer suppression sheet and battery module

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015083787A (en) * 2013-10-25 2015-04-30 村井商事株式会社 Heat insulation cover for high heat part of marine engine
JP2021507483A (en) * 2017-12-21 2021-02-22 ハー カー オー イゾリアー ウント テクスティルテヒニーク ゲゼルシャフト ミット ベシュレンクテル ハフツング Multi-layer insulation element for batteries
WO2022009852A1 (en) * 2020-07-10 2022-01-13 イビデン株式会社 Heat transfer suppression sheet and battery pack

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015083787A (en) * 2013-10-25 2015-04-30 村井商事株式会社 Heat insulation cover for high heat part of marine engine
JP2021507483A (en) * 2017-12-21 2021-02-22 ハー カー オー イゾリアー ウント テクスティルテヒニーク ゲゼルシャフト ミット ベシュレンクテル ハフツング Multi-layer insulation element for batteries
WO2022009852A1 (en) * 2020-07-10 2022-01-13 イビデン株式会社 Heat transfer suppression sheet and battery pack

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