JP2004327046A - Battery case with explosion-proof structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery case used for a sheet-like battery such as a polymer battery, thin in thickness, light in weight and excellent in gas barrier property against steam and the like, heat-sealing property as well as a variety of strength and durability, and also equipped with an explosion-proof structure when the inner pressure is increased. <P>SOLUTION: The battery case is formed by using a laminated film 100 having an aluminum foil layer 1 as an intermediate layer and laminating an outside synthetic resin layer 2 and an inside synthetic resin layer 3 on the both surfaces of the foil layer 1, and by providing a half cut portion in a pattern shape by irradiating a laser beam at least one surface of the film 100, for at least a part of the battery case. Preferably, films 4a such as a PET film, an ON film, an OPP film are used for the resin layer 2, and the resin layer 3 is composed of at least two layers 4b such as the PET film, the ON film and the OPP film and a heat-bonding resin layer 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery case for forming a battery by storing constituent materials of the battery, and more particularly to a battery case that is suitably used for a case such as a sheet-shaped battery, has an explosion-proof structure, and is excellent in safety. .
[0002]
[Prior art]
Conventionally, a metal case has been used in most cases as a battery case for accommodating constituent materials of the battery. However, with the development and spread of various electronic devices such as notebook personal computers and mobile phones, their weight and thickness have been reduced, and the batteries used in these devices have been made as light as possible. Lighter and thinner devices are required to reduce the space for batteries in equipment.
[0003]
In order to meet such demands, for example, various sheet-shaped batteries that are made light and thin in a sheet shape by introducing a polymer material into an electrode or an electrolyte of the battery have been researched and developed.
In such a sheet-like battery, the battery case serving as the outer wall material is also preferably in the form of a thin and light film. For example, a base film layer such as plastic and a barrier layer, and a heat-adhesive resin layer (Sealant layer) A bag-like battery case with one end opened is manufactured using a laminated film in which layers are stacked, and the constituent materials of the battery are housed inside, and the electrode terminals are extended outward from the inside through the opening. A sheet-shaped battery is manufactured by sealing the opening by thermal bonding.
[0004]
The laminated film used for such a battery case has not only its lightness and thinness, but also various performances such as various strengths and resistances, gas barrier properties such as water vapor and the like, heat sealing properties, and thermal adhesion to electrode terminals. Required.
For this purpose, for example, a metal foil such as an aluminum foil having excellent gas barrier properties such as water vapor or the like is used for the intermediate layer, and various strengths and resistances are provided on both sides thereof, and a base is provided for protecting the metal foil. A method of laminating a biaxially stretched plastic film as a material film and laminating a polyethylene or other polyolefin-based resin as a heat-adhesive resin layer (sealant layer) on the innermost layer to form a laminated film is adopted. .
[0005]
By using such a laminated film in the case of a sheet-shaped battery such as a polymer battery, it is possible to produce a sheet-shaped battery that is almost satisfactory in various strengths, durability, and performance such as water vapor and other gas barrier properties. it can.
[0006]
On the other hand, a lithium-ion battery using a metal deep-drawing container for the battery case has an internal pressure rise due to an abnormal rise in temperature inside the battery, which may cause an explosion. .
In this regard, a polymer battery in which a laminated film is used for a battery case has generally not required a pressure release valve.
However, in order to further enhance the safety of the polymer battery, it is preferable to provide a pressure release valve, and it has been demanded to provide some kind of safety valve.
[0007]
From such a background, there has been a polymer battery in which a gas release valve (trade name, manufactured by Aroma Fin Valve BOSCH), which is developed for a packaging bag of roasted coffee, is attached as a pressure release valve to a battery case made of a laminated film. .
However, such a gas release valve is configured to release an excessive gas when the internal pressure reaches a certain level due to the gas generated in the bag to maintain the internal pressure in a certain range. Has the effect of preventing it from rising above a certain value, but the valve itself does not have much gas barrier properties, and when used in a polymer battery, the water vapor and other gas barrier properties are reduced, and the performance of the battery is reduced. There was a problem.
[0008]
[Problems to be solved by the invention]
The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a laminated film used for a thin and lightweight battery case such as a polymer battery with various strengths and durability. In addition to being formed with a structure having water vapor and other gas barrier properties and heat sealing properties, a part of the laminated film is broken by a certain pressure without impairing the water vapor and other gas barrier properties to reduce the internal pressure. By providing an open valve that can be opened, it is thin and light, and in addition to various strengths and resistances, it is excellent in steam and other gas barrier properties, heat sealing properties, etc. It also has an explosion proof property and excellent safety. An object of the present invention is to provide a battery case with excellent performance.
[0009]
[Means for Solving the Problems]
The above problem can be solved by the present invention described below.
That is, the invention described in claim 1 is a battery case used for forming a battery by housing the constituent materials of the battery therein, and using an aluminum foil layer as an intermediate layer in at least a part of the case. A battery case is provided with an explosion-proof structure in which a laminated film having a synthetic resin layer laminated on both surfaces is used, and a half-cut portion is provided on at least one surface of the laminated film by laser light irradiation.
[0010]
In the present invention, the half-cut portion is a layer of the synthetic resin layer on the irradiation side of the intermediate layer of the aluminum foil layer of all the layers in the thickness direction of the laminated film by laser light irradiation. This indicates a portion where a part of the layer is melted and mist-formed linearly and removed.
Further, the explosion-proof structure refers to a portion in which the half-cut portion is provided in the laminated film in a predetermined shape to reduce the rupture strength of that portion, so that the laminated film is broken at a certain range of pressure. It is.
[0011]
By adopting such a configuration, the laminated film used for the battery case has an aluminum foil layer in the intermediate layer, is excellent in water vapor and other gas barrier properties, and has half cut by laser beam irradiation on at least one surface thereof. The aluminum foil layer is not damaged during processing because it has an explosion-proof structure in which the burst strength is adjusted to a low level, so excellent barrier properties are maintained, and the internal pressure of the battery rises when abnormal. However, since the explosion-proof structure is broken at a constant internal pressure and the internal pressure is released, a battery case which does not explode and has excellent safety can be provided.
[0012]
The bursting strength of the explosion-proof structure by the half cut portion is 5 to 10 kg / cm. ² A battery case provided with the explosion-proof structure according to claim 1.
[0013]
By adopting such a configuration, the burst strength of the battery case is appropriately adjusted, so that even if the internal pressure of the battery rises in an abnormal case, the explosion-proof structure does not function and the battery does not explode, so that it is more reliable. Safety is obtained.
The burst strength is 5 kg / cm ² When the value is less than the above, the breaking strength of the laminated film also decreases, and thus the laminated film may be damaged during handling of the battery, which is not preferable. Also, the burst strength is 10 kg / cm ² If it exceeds, the danger at the time of rupture increases and the effect as an explosion-proof structure is reduced, which is not preferable.
[0014]
The invention described in claim 3 is the battery case provided with the explosion-proof structure according to claim 1 or 2, wherein the half-cut portions are formed by a combination of lines that intersect or intersect with each other. .
[0015]
By adopting such a configuration, when adjusting the burst strength of the explosion-proof structure by the half-cut portion, adjustment on the low-pressure side becomes easy, the variation can be reduced, and a stable explosion-proof structure can be formed.
[0016]
The invention described in claim 4 is characterized in that the half-cut portions are provided on both surfaces of the laminated film so as to overlap at the same position. It is a battery case provided with an explosion-proof structure.
[0017]
By adopting such a configuration, the burst strength of the explosion-proof structure by the half-cut portion can be further reduced and its variation can be reduced, so that a safer explosion-proof structure can be reliably formed.
[0018]
In the invention described in claim 5, the battery case is formed of a bag formed by thermally bonding the laminated film in a bag shape, and the half-cut portion is provided near a peripheral edge of the bag body. A battery case provided with the explosion-proof structure according to any one of claims 1 to 4.
[0019]
By adopting such a configuration, the battery case can be formed only of the laminated film, so that the battery case can be made thinner and lighter, and at the same time, the price can be reduced, and the half-cut portion is provided near the periphery of the bag body. Accordingly, when an internal pressure is generated, the stress is likely to be applied, and the function of the explosion-proof structure can be more reliably obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a material and a processing method of a battery case having an explosion-proof structure of the present invention will be described.
The battery case provided with the explosion-proof structure of the present invention, as described above, is a battery case that is used to form a battery by housing the constituent materials of the battery therein, and at least a part of the case includes aluminum. A laminated film in which a synthetic resin layer was laminated on both surfaces with a foil layer as an intermediate layer was used, and at least one surface of the laminated film was provided with an explosion-proof structure in which a half-cut portion was provided by laser light irradiation. It is characterized by the following.
[0021]
Such a battery case is preferably formed from a laminated film provided with the above explosion-proof structure in a bag shape and formed only with the laminated film. The battery case can also be formed by partially using a laminated film provided with the explosion-proof structure.
[0022]
The laminated film is formed by laminating a synthetic resin layer on both surfaces, that is, a surface on the outside of the battery case and a surface on the inside, with the aluminum foil layer serving as a barrier layer and a laser light blocking layer as an intermediate layer. .
And, the outer synthetic resin layer has various strengths and resistances, and because it is provided with a half-cut portion by laser light irradiation, it is necessary that it absorbs laser light, generates heat, melts, and forms mist. It is preferable to have processing suitability such as printing and lamination. For example, a biaxially stretched polyethylene terephthalate film, a biaxially stretched nylon film, a biaxially stretched polyethylene naphthalate film, a biaxially stretched polypropylene film, or the like can be used. .
These may use a single film, or may use a laminated film laminated with another film.
Hereinafter, the biaxially stretched polyethylene terephthalate film is abbreviated as a PET film, the biaxially stretched nylon film is abbreviated as an ON film, and the biaxially stretched polypropylene film is abbreviated as an OPP film.
[0023]
Among the above plastic films, PET films in particular have low hygroscopicity and are excellent in rigidity, tensile strength, bending strength, impact strength, scratch resistance, heat resistance, water resistance, etc., and have comprehensively balanced performance. In addition, it can be suitably used because it is relatively inexpensive and excellent in economy.
The ON film has a slightly higher hygroscopicity than the PET film, but is rich in flexibility, excellent in piercing strength, impact strength, bending strength, cold resistance, etc., and is suitable when such performance is important. Can be used.
The OPP film is excellent in moisture resistance, water resistance, chemical resistance, tensile strength, bending strength, and the like, and is particularly advantageous in that it is inexpensive.
By laminating such a plastic film on the aluminum foil of the intermediate layer by a known dry lamination method or the like, the outer synthetic resin layer can be laminated.
The thickness of such a plastic film, that is, the outer synthetic resin layer, is preferably from 8 to 80 μm, more preferably from 12 to 30 μm.
[0024]
Next, the synthetic resin layer inside the laminated film reinforces the strength of the laminated film, protects the aluminum foil layer of the intermediate layer, and at the same time, provides a half-cut portion by laser light irradiation, so that its processing suitability is improved. In addition, in order to form a bag and form a bag, and also to heat-seal the opening edge portion where the electrode terminal is interposed, it has not only the self-adhesive property but also the thermo-adhesive property to the surface of the electrode terminal. It is necessary.
However, since it is difficult to combine such performance with a single resin layer (such as a film), it is preferable to configure the resin layer with at least two layers.
For example, it is composed of two layers, a plastic film layer similar to that used for the outer synthetic resin layer and a heat-adhesive resin layer (sealant layer), and the plastic film layer is laminated on the aluminum foil layer side of the intermediate layer. Then, the heat-adhesive resin layer can be laminated so as to be the innermost layer.
[0025]
In addition, in addition to polyethylene, the ethylene-α-olefin copolymer-based resin, ethylene-vinyl acetate copolymer-based resin, ethylene-acrylate copolymer-based resin, ethylene -A methacrylic acid ester copolymer resin, an ethylene-acrylic acid copolymer resin, an ethylene-methacrylic acid copolymer resin, an acid-modified polyolefin resin, an ionomer, and the like can be used. These may be used alone or as a mixture of two or more.
Among these, suitable materials can be appropriately selected and used in consideration of the material of the surface of the electrode terminal (presence or absence of surface coating).
[0026]
The thickness of the plastic film layer used for the inner synthetic resin layer does not need to be so large, and is suitably about 8 to 30 μm.
The thickness of the innermost heat-adhesive resin layer is preferably from 15 to 100 μm, more preferably from 30 to 80 μm.
[0027]
Further, the thickness of the aluminum foil layer as the intermediate layer is preferably 5 to 25 μm, more preferably 7 to 15 μm.
When the thickness of the aluminum foil layer is less than 5 μm, pinholes increase and the gas barrier properties of water vapor and the like are unfavorably reduced, and a thickness exceeding 25 μm has a sufficient gas barrier property already. There is no necessity, and the burst strength of the half-cut portion is increased, which is not preferable.
[0028]
In the case where, for example, an aluminum foil having a thickness of 9 μm is used for the intermediate layer, the water vapor permeability is 0.01 g / (m ² (24 hrs), (40 ° C., 90% RH) or less can be easily obtained, and it is easy to further improve the performance.
[0029]
In the present invention, a part of the laminated film composed of the above materials is irradiated with a laser beam, and all or part of the synthetic resin layer laminated on both surfaces of the aluminum foil layer is formed into a predetermined linear shape. The rupture strength of this portion is 5 to 10 kg / cm by forming a half-cut portion by melting and mist removal in a pattern of ² To the explosion-proof structure.
[0030]
In order to provide such a half cut portion, a known laser beam irradiation means can be used, and a carbon dioxide gas laser is particularly suitable.
The wavelength of the carbon dioxide laser beam is 10.6 μm, and the PET film, ON film, OPP film, etc. mentioned in the synthetic resin layer of the laminated film absorb this and generate heat, so that the half cut portion is easily formed. can do.
However, low-density polyethylene, which is widely used as a heat-adhesive resin, hardly absorbs laser light of this wavelength and transmits the laser light, and thus does not generate heat and is not suitable for processing by laser light. However, when used by laminating with the PET film, the ON film, the OPP film, or the like, these generate heat, so that they are melted by the heat to form a half-cut portion in the same manner.
[0031]
Therefore, like the synthetic resin layer on the inner surface side of the laminated film in the present invention, a two-layer structure of a PET film, an ON film, an OPP film, and the like, and a heat-adhesive resin layer, In the case of using polyethylene, for example, by adjusting the relative thickness configuration of the two and the irradiation conditions of the laser beam, for example, a half-cut portion in which all layers of the synthetic resin layer on the inner surface side are removed in a linear pattern. It can also be formed, and only layers such as PET film, ON film, and OPP film that absorb laser light are removed in a linear pattern, and the low-density polyethylene layer is once melted and cleaved in a linear pattern. After that, it is possible to form a half-cut portion which is re-fused and connected to form a hollow shape in a linear pattern.
[0032]
【Example】
Hereinafter, the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to these drawings.
[0033]
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a laminated film used for a battery case having an explosion-proof structure of the present invention.
FIG. 2 is a view showing a typical example of a pattern of a half-cut portion provided on a laminated film by irradiating a laser beam in the present invention, wherein (a), (b), (c), and (d) are: It is a figure which shows an example each.
FIGS. 3A and 3B are schematic diagrams each showing a cross-sectional shape of a half-cut portion of one embodiment provided on the laminated film.
FIG. 4 is an exploded view of the battery case when the battery case having the explosion-proof structure of the present invention is manufactured in a three-side sealed bag shape.
FIG. 5 is a front view showing the configuration of a battery manufactured using the battery case shown in the development view of FIG.
[0034]
The laminated film 100 shown in FIG. 1 uses an aluminum foil layer 1 as an intermediate layer, laminates an outer synthetic resin layer 2 on an outer surface (an upper surface in the figure), and an inner surface (a lower side in the figure). (Surface) is laminated with the inner synthetic resin layer 3.
The outer synthetic resin layer 2 is specifically composed of a PET film, an ON film, an OPP film or the like 4a, and the inner synthetic resin layer 3 is laminated on the aluminum foil layer 1 of the intermediate layer. It is composed of at least two layers of a 4b layer such as a PET film, an ON film, an OPP film and an innermost layer of a thermo-adhesive resin layer 5 laminated thereon.
[0035]
In the structure of the laminated film, 4a such as a PET film, an ON film, and an OPP film of the outer synthetic resin layer 2 and 4b such as a PET film, an ON film, and an OPP film of the inner synthetic resin layer 3 are formed of these single films. Or a laminated film in which another film is laminated on these films.
Further, the heat-adhesive resin layer 5 of the inner synthetic resin layer 3 may be formed of a single heat-adhesive resin layer, or may be formed of a plurality of heat-adhesive resin layers.
[0036]
As a method of laminating 4a, 4b such as a PET film, an ON film, an OPP film and the like on the intermediate aluminum foil layer 1, it is preferable to use a known dry lamination method using an adhesive. Extrusion lamination with an interposition can also be used.
Further, as for the method of laminating the innermost layer of the heat-adhesive resin layer 5, it is easy to adopt the extrusion coating method. However, the heat-adhesion resin film previously formed into a film shape is subjected to the dry lamination method or the extrusion method. Lamination can also be performed by a lamination method.
[0037]
The following configuration is mentioned as a typical specific example of the configuration of the laminated film. In addition, the pretreatment and the adhesive layer used for lamination are omitted.
(1) PET film (thickness 16 μm) / aluminum foil (thickness 9 μm) / PET film (thickness 12 μm) / thermal adhesive resin layer (thickness 40 μm) [sealant layer]
(2) ON film (thickness 15 μm) / aluminum foil (thickness 9 μm) / PET film (thickness 12 μm) / heat-adhesive resin layer (thickness 40 μm) [sealant layer]
(3) OPP film (thickness: 20 μm) / aluminum foil (thickness: 9 μm) / PET film (thickness: 12 μm) / heat-adhesive resin layer (thickness: 40 μm) [sealant layer]
(4) PET film (thickness 16 μm) / aluminum foil (thickness 9 μm) / OPP film (thickness 20 μm) / thermal adhesive resin layer (thickness 40 μm) [sealant layer]
(5) PET film (thickness 16 μm) / aluminum foil (thickness 9 μm) / ON film (thickness 15 μm) / heat-adhesive resin layer (thickness 40 μm) [sealant layer]
[0038]
(6) ON film (thickness 15 μm) / PET film (thickness 12 μm) / aluminum foil (thickness 9 μm) / PET film (thickness 12 μm) / heat-adhesive resin layer (thickness 40 μm) [sealant layer]
(7) PET film (thickness 12 μm) / ON film (thickness 15 μm) / aluminum foil (thickness 9 μm) / PET film (thickness 12 μm) / heat-adhesive resin layer (thickness 40 μm) [sealant layer]
(8) PET film (thickness 12 μm) / OPP film (thickness 20 μm) / aluminum foil (thickness 9 μm) / PET film (thickness 12 μm) / heat-adhesive resin layer (thickness 40 μm) [sealant layer]
[0039]
In the present invention, the laminated film as described above is irradiated with a laser beam to form a patterned half-cut portion, and its burst strength is 5 to 10 kg / cm. ² By adjusting to, this is an explosion-proof structure.
The pattern of the half cut portion formed for such a purpose is not particularly limited, and can be formed in an arbitrary pattern depending on the material and thickness of the synthetic resin layer of the laminated film.
As a pattern that can be effectively used for such a half-cut portion, for example, a pattern as shown in FIG.
[0040]
That is, the patterns of the half-cut portions shown in (a), (b), (c), and (d) of FIG. 2 are all formed by straight lines extending radially outward from the center point. (A) is a pattern in which three straight lines from the center point are radially formed so that the center angle is 120 °, and (b) is a pattern in which four straight lines are formed from the center point and the center angle is 90 °. (C) is a pattern formed radially so that the central angle is 60 °, and (D) is a pattern formed radially so that the central angle is 60 °. Eight straight lines from the center point are patterns formed radially so that the center angle forms 45 °.
[0041]
In the above-mentioned pattern, the effect of reducing the burst strength increases with an increase in the number of the straight lines. Therefore, the pattern can be appropriately selected and used according to the configuration of the laminated film. Further, the size of these patterns is not particularly limited, but it is appropriate that the length of the straight line is about 10 to 15 mm, that is, the cross length of the pattern is about 20 to 30 mm.
Such a pattern-shaped half-cut portion may be provided on one side of the laminated film, for example, only on the outer synthetic resin layer. The effect of reducing the burst strength can be increased.
[0042]
FIG. 3 shows a laminated film in which a PET film layer / aluminum foil layer / PET film layer / polyolefin resin layer (sealant layer) is laminated in order from the outside as a laminated film. FIG. 4 is a schematic view showing a cross-sectional shape of a straight line portion when a half-cut portion is provided by irradiating the same position on both sides of the synthetic resin layer so as to overlap each other.
In particular, in the case of the innermost synthetic resin layer, when the innermost polyolefin-based resin layer is a resin layer that does not absorb laser light, such as low-density polyethylene, the thickness of the resin layer and the irradiation conditions of the laser light are adjusted to adjust the thickness of FIG. As shown in (a) and (b), it can be provided in two shapes.
[0043]
That is, as shown in (a), a half-cut portion in which the synthetic resin layers on both sides are removed linearly is usually formed as shown in (a), but the thickness of the polyolefin resin layer is reduced. By increasing the thickness to, for example, 40 μm or more and adjusting the irradiation energy of the laser beam to a constant condition, the PET film layer generates heat in the inner synthetic resin layer as shown in (b). After the whole is melted linearly, misted and cleaved, the polyolefin-based resin layer is re-deposited, and as a result, the PET film layer of the inner synthetic resin layer is removed in a tunnel shape as shown in (b). A half-cut portion having an inclined shape can be provided.
[0044]
FIG. 4 is an exploded view of the battery case when the battery case having the explosion-proof structure of the present invention is manufactured in a three-side sealed bag shape.
The battery case shown in the developed view is formed of the laminated film 100 having the laminated structure shown in FIG. 1 and is cut into a rectangle at a predetermined size as shown in FIG. In the vicinity of the folding line 6, four straight lines extending outward from the center point, and the half-cut portions 10 of the pattern formed radially so that the center angle forms 90 ° are at the same position on both surfaces of the laminated film. It is provided so as to overlap, and at the peripheral edge of the rectangular laminated film 100, as a heat seal space for heat sealing in a bag shape, body heat seal portions 7a, 7b, 7c on both left and right sides. 7d is provided, and openings heat seal portions 8a and 8b are provided on both upper and lower sides.
[0045]
Therefore, such a laminated film 100 is half-folded at the folding line 6 so that the heat-adhesive resin layers are opposed to each other, and the right and left edges are torso heat seal portions (7a, 7b), By heat-sealing at (7c, 7d), a half-cut portion 10 is provided near the fold line 6 at the bottom, and a half-cut portion 10 is provided in the vicinity thereof, and the body heat-seal portions (7a, 7b) and (7c, 7d) at both sides. It is possible to produce a rectangular bag-shaped battery case which is sealed and whose upper part, that is, the opening heat seal portions 8a and 8b are unsealed and opened.
[0046]
Such a bag-shaped battery case is filled with the constituent material of the battery from the upper opening, the electrode terminals are extended from the inside through the opening, and the opening is formed between the heat-adhesive resin layers of the battery case. In addition, by performing heat sealing between the heat-adhesive resin layer and the electrode terminals and sealing, a battery having an explosion-proof structure with a half-cut portion as shown in FIG. 5 can be manufactured.
[0047]
That is, FIG. 5 is a front view showing a configuration of a battery manufactured by using the battery case shown in the development view of FIG. 4, and the battery case of the battery 200 has the battery case shown in FIG. As described above, the laminated film 100 is folded in half, and both sides are sealed with the body heat seal portions (7a, 7b) and (7c, 7d). The battery is filled with the constituent materials, the electrode terminals 9a, 9b are extended from the inside to the outside through the openings, and the opening heat-seal portions 8a, 8b are formed by heat sealing as described above. This is a configuration provided with an explosion-proof structure by the half cut portion 10 in the vicinity.
[0048]
【The invention's effect】
As described above in detail, according to the present invention, an intermediate layer has an aluminum foil layer, and is formed of a laminated film in which synthetic resin layers are laminated on both sides thereof, and is thin, light, flexible, and In addition to various strengths and resistances, it has excellent performance such as steam and other gas barrier properties, heat sealing properties, and explosion-proof structure that can release the internal pressure at a predetermined pressure even if the internal pressure rises due to internal heating due to misuse etc. Thus, an effect of being able to provide a highly safe battery case with high productivity is achieved.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a laminated film used for a battery case having an explosion-proof structure of the present invention.
FIG. 2 is a view showing a typical example of a pattern of a half-cut portion provided on a laminated film by irradiating a laser beam in the present invention, wherein (a), (b), (c), and (d) are: It is a figure which shows an example each.
FIGS. 3A and 3B are schematic views showing the cross-sectional shapes of a half-cut portion of one embodiment provided on a laminated film, respectively.
FIG. 4 is a development view of the battery case when the battery case having the explosion-proof structure of the present invention is manufactured in a three-sided sealed bag shape.
FIG. 5 is a front view showing the configuration of a battery manufactured using the battery case shown in the developed view of FIG.
[Explanation of symbols]
1 Aluminum foil layer
2 Outer synthetic resin layer
3 Inner synthetic resin layer
4a, 4b PET film, ON film, OPP film, etc.
5 Thermal adhesive resin layer
6 folding line
7a, 7b, 7c, 7d Body heat seal part
8a, 8b Opening heat seal part
9a, 9b electrode terminals
10 Half cut part
100 laminated film
200 batteries

Claims (5)

A battery case used for forming a battery, containing a battery constituent material therein, wherein at least a part of the case has a synthetic resin layer laminated on both sides with an aluminum foil layer as an intermediate layer. And a battery case having an explosion-proof structure in which a half-cut portion is provided on at least one surface of the laminated film by laser light irradiation. ^{2. The} battery case according to claim 1, wherein a burst strength of the explosion-proof structure by the half-cut portion is 5 to 10 kg / cm < ² >. 3. The battery case according to claim 1, wherein the half-cut portions are formed by a combination of lines that intersect or intersect with each other. 4. 4. The battery case according to claim 1, wherein the half cut portions are provided on both surfaces of the laminated film so as to overlap at the same position. 5. 2. The battery case according to claim 1, wherein the battery case is formed of a bag formed by thermally bonding the laminated film in a bag shape, and the half-cut portion is provided near a peripheral edge of the bag. A battery case provided with the explosion-proof structure according to any one of claims 1 to 4.

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