JP7183794B2 - Thermoelectric conversion module - Google Patents

Description

The present invention relates to thermoelectric conversion modules.

In recent years, attention has been focused on thermoelectric conversion modules that convert heat into electricity by utilizing temperature differences. Among them, as a thermoelectric conversion module, since the electromotive force is large, a thermoelectric conversion module including a joint formed by joining a p (positive) type semiconductor material and an n (negative) type semiconductor material is attracting attention. ing. Thermoelectric conversion modules are expected as effective means for utilizing unused thermal energy.

Here, as the thermoelectric conversion module, a thermoelectric conversion module having a structure including a thermoelectric conversion element configured by alternately arranging p-type elements and n-type elements in a plane and an outer layer member having a plurality of convex portions. have been proposed (see, for example, Patent Document 1). In the thermoelectric conversion module described in Patent Literature 1, the protrusions of the outer layer member are thermally coupled to positions corresponding to the connecting portions of the p-type element and the n-type element. More specifically, in Patent Document 1, a plurality of p-type elements and n-type elements are formed by alternately arranging protrusions made of a material with high thermal conductivity on both upper and lower sides of the plane of the thermoelectric conversion element. A structure is disclosed for alternately transferring heat and cold to the connections of the. According to such a structure, the outer layer member arranged on the high temperature side recovers heat from the heat source and transmits it to the thermoelectric conversion element via the convex portion, while the cold heat is obtained by the outer layer member arranged on the low temperature side and the convex It was possible to transmit to the thermoelectric conversion element through the part.

JP 2014-154761 A

Here, the thermoelectric conversion module is required to have high thermoelectric conversion efficiency and high flexibility so as to be compatible with various mounting modes. However, the structure described in Patent Document 1, which uses both heat transfer from the high temperature side and cold heat transfer from the low temperature side to increase the temperature difference in the PN connection direction of the thermoelectric conversion element, has a thermoelectric conversion efficiency There is room for improvement in terms of achieving both flexibility and flexibility.

Accordingly, an object of the present invention is to provide a thermoelectric conversion module that is compatible with thermoelectric conversion efficiency and flexibility.

An object of the present invention is to advantageously solve the above problems. A thermoelectric conversion module of the present invention is a thermoelectric conversion module that converts heat from a heat source into electric power, and A film-shaped thermoelectric conversion element body having a p-type thermoelectric conversion element and an n-type thermoelectric conversion element bonded along a certain bonding direction; a thermal conductor coupled to the junction of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element only on the first surface, the first surface being the first surface and the other surface being the second surface; characterized by In this way, if the thermoelectric conversion module has a structure including a heat conductor joined to the joints of the thermoelectric conversion elements only on the first surface that receives heat from the heat source, the thermoelectric conversion efficiency of the thermoelectric conversion module and flexibility can be compatible.

Here, in the thermoelectric conversion module of the present invention, the film-like thermoelectric conversion element body is formed by continuously bonding at least two pairs of p-type thermoelectric conversion elements and n-type thermoelectric conversion elements, and the heat conductor is composed of the above A plurality of junctions of at least two pairs of the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements are coupled alternately, and the junctions to which the thermal conductors are coupled are electrically conductive and It preferably comprises a metallic material having thermal conductivity. In the thermoelectric conversion module, if the joint where the heat conductor is bonded contains a metal material having electrical and thermal conductivity, the heat transfer efficiency is increased, and the thermoelectric conversion efficiency of the thermoelectric conversion module can be further increased. .

Further, in the thermoelectric conversion module of the present invention, a joint portion to which the heat conductor is not joined among the plurality of joint portions is formed by directly joining the p-type thermoelectric conversion element and the n-type thermoelectric conversion element. preferable. In the thermoelectric conversion module, if the joints to which the thermal conductor is not joined are formed by directly joining thermoelectric conversion elements with different conductivity types, the temperature difference in the joining direction of the thermoelectric conversion elements is further increased. It is possible to further improve the thermoelectric conversion efficiency of the thermoelectric conversion module.

Further, in the thermoelectric conversion module of the present invention, it is preferable that the film-like thermoelectric conversion element has at least one thermoelectric conversion element substrate, and the thermoelectric conversion element substrate has at least one vent hole. . In the thermoelectric conversion module, if the thermoelectric conversion elements are supported by a thermoelectric conversion element substrate having vents, the strength of the thermoelectric conversion elements is increased and the temperature difference in the joining direction of the thermoelectric conversion elements is further increased. be able to.

Further, in the thermoelectric conversion module of the present invention, it is preferable that each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element has a length of 5 mm or more in the joining direction. If the junction direction length of each thermoelectric conversion element constituting the thermoelectric conversion element body is 5 mm or more, the temperature difference in the junction direction of the thermoelectric conversion element body can be further increased, and the thermoelectric conversion efficiency of the thermoelectric conversion module can be further improved. can be enhanced.

In addition, the thermoelectric conversion module of the present invention preferably includes heat insulation regions adjacent to both sides of the heat conductor in the joining direction, and further preferably has a radiation reflector and/or a radiation preventer within the heat insulation region. . If a radiation reflector and/or a radiation preventer is arranged in the heat insulation on both sides of the joining direction of the heat conductor, the temperature difference in the joining direction of the thermoelectric conversion element can be further increased, and the thermoelectric conversion module can be used. Conversion efficiency can be further increased.

Further, in the thermoelectric conversion module of the present invention, it is preferable that continuous junctions of the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements forming the film-like thermoelectric conversion element body are arranged in a meandering manner. If the continuous assembly of a plurality of thermoelectric conversion elements constituting the thermoelectric conversion element body is arranged in a meandering manner, the thermoelectric conversion elements can be efficiently integrated and arranged in a limited space, and the thermoelectric conversion module can be used. Conversion efficiency can be further increased.

Further, in the thermoelectric conversion module of the present invention, the plurality of heat conductors coupled to the continuous joints arranged in a meandering manner are interconnected in a direction perpendicular to the joining direction within the plane. It is preferable to be If a plurality of heat conductors connected to a meandering continuous joint are interconnected in the direction perpendicular to the joint direction, flexibility in the joint direction and flexibility perpendicular to the joint direction It is possible to achieve both strength in the direction.

Further, in the thermoelectric conversion module of the present invention, it is preferable that each of the plurality of heat conductors connected to the meanderingly arranged continuous joint body is spaced apart from other heat conductors. The flexibility of the thermoelectric conversion module can be further enhanced if the plurality of heat conductors coupled to the meanderingly arranged continuous joints are spaced apart from each other.

Further, in the thermoelectric conversion module of the present invention, each p-type thermoelectric conversion element or n-type thermoelectric conversion element arranged at each end in the joining direction of the continuous joint body arranged in a meandering manner is arranged at each end and another n-type thermoelectric conversion element or p-type thermoelectric conversion element of different conductivity type to be joined, and the end joint is directly joined, and the end joint has an L-shaped end or It is preferable to form the p-type thermoelectric conversion element and/or the n-type thermoelectric conversion element having an inverted L shape. If the thermoelectric conversion elements having end shapes deformed into L-shapes or inverted L-shapes are directly bonded to each other at both ends in the bonding direction of the continuous bonded body arranged in a meandering manner, the thermoelectric conversion module can be made flexible. It is possible to further enhance sexuality.

ADVANTAGE OF THE INVENTION According to this invention, the thermoelectric conversion module which can make thermoelectric conversion efficiency and flexibility compatible can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the schematic structure of the thermoelectric conversion module of this invention. FIG. 4 is a plan view showing another example of the schematic structure of the thermoelectric conversion module of the present invention; FIG. 4 is a plan view showing still another example of the schematic structure of the thermoelectric conversion module of the present invention; FIG. 4 is a plan view showing still another example of the schematic structure of the thermoelectric conversion module of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In addition, in each figure, the thing which attached|subjected the same code|symbol shall show the same component.

Here, the thermoelectric conversion module of the present invention is not particularly limited, and may be a temperature control element that can be used in a cold storage or the like, a power generation element for waste heat power generation, snow and ice power generation, or the like, and a lithium ion battery or the like. It can be used as an electrode for Moreover, the heat source of the thermoelectric conversion module of the present invention is not particularly limited, and may be, for example, a heat source such as electrical equipment, or a cold heat source such as liquefied natural gas, snow, or ice. In the following description, for the sake of clarity, it is assumed that the temperature of the heat source is higher than the temperature on the high temperature side of the temperature gradient to be formed in the thermoelectric conversion element, that is, the heat source is a heat source other than a cold heat source. to explain.

FIG. 1 is a cross-sectional view showing a schematic structure of a thermoelectric conversion module 100 according to one example of the present invention. One surface of the thermoelectric conversion module 100 is a first surface that receives heat from a heat source, and the other surface is a second surface opposite to the first surface. The first surface is the high temperature side facing the high temperature atmosphere, and the second surface is the low temperature side facing the low temperature atmosphere. A hot side of the thermoelectric conversion module 100 may be placed adjacent to the heat source 200 . In FIG. 1, the lower side is shown as the high temperature side and the upper side as the low temperature side.

The thermoelectric conversion module 100 includes a film-like thermoelectric conversion element body 10 in which a p-type thermoelectric conversion element 1 and an n-type thermoelectric conversion element 2 are bonded along a bonding direction that is one in-plane direction. In the drawing, the thermoelectric conversion element body 10 is shown as having three pairs of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2. However, the thermoelectric conversion element body 10 is not limited to this, and the thermoelectric conversion element body 10 includes at least It is sufficient to have a pair of p-type thermoelectric conversion element 1 and n-type thermoelectric conversion element 2 . The thermoelectric conversion element body 10 has one surface as a high-temperature side that receives heat from a heat source and the other surface as a low-temperature side. a thermal conductor 4 coupled to the joint 3A of the . On both sides of the heat conductor 4 along the joining direction of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2, heat insulating regions 5 are arranged adjacent to each other. The thermoelectric conversion module 100 having such a structure can achieve both thermoelectric conversion efficiency and flexibility at a high level. The reason for this is not clear, but is presumed to be as follows. First, in a structure in which thermal conductors are arranged on both sides of a film-shaped thermoelectric conversion element, the presence of the thermal conductors arranged on both sides cannot sufficiently improve the flexibility of the thermoelectric conversion module. there were. In addition, according to studies by the present inventors, in a thermoelectric conversion module having a structure in which thermal conductors are arranged on both sides of a film-like thermoelectric conversion element, the materials of the constituent members, the size of the module, the temperature of the heat source, etc. It has become clear that, depending on the combination of various conditions, there may be cases where radiant heat from the heat source conducts to the heat conductor placed on the low temperature side. If the heat conductor arranged on the low-temperature side is warmed, the temperature difference generated in the thermoelectric conversion element body will rather be narrowed. Therefore, the present inventors have proposed a structure in which the heat conductor 4 is joined only at the joint portion of the high temperature side without arranging the heat conductor on the low temperature side of the film-shaped thermoelectric conversion element body 10. Thus, a structure has been created that can avoid narrowing the temperature difference generated in the thermoelectric conversion element body 10 and can suppress an excessive decrease in the flexibility of the thermoelectric conversion module.

Here, the heat insulating region 5 adjacent to the heat conductor 4 can be made of a material with a lower thermal conductivity than the heat conductor 4, or a vacuum. Furthermore, the material having a lower thermal conductivity than the heat conductor 4 is preferably a material having a lower thermal conductivity than the thermoelectric conversion element substrates 11 and 12, which will be described later, and more preferably a heat insulating material. Specifically, such substances include, but are not particularly limited to, inorganic fiber-based heat insulating materials, foamed plastic-based heat insulating materials, and air having a thermal conductivity of less than 0.1 W/m·K. Preferably, a heat insulating material with less than 0.06 W/m·K is mentioned. Among others, the heat insulating substance is preferably air. This is because the fluidity of the air enhances the heat insulating effect, and the temperature gradient in the joining direction of the thermoelectric conversion element bodies 10 can be enhanced.

Furthermore, it is preferable that a radiation reflector 21 and/or a radiation blocker 22 are arranged in the heat insulating region 5 . Here, the heat insulating region 5 faces the high-temperature side surface of the thermoelectric conversion element body 10, and is partitioned on four sides by, for example, two heat conductors 4, a substrate 6 described later, and the high-temperature side surface of the thermoelectric conversion element body 10. is a void. The radiation reflector 21 may be placed anywhere within the heat insulating region 5 as long as it is not in contact with the substrate 6 . According to the radiation reflector 21 with such a specific arrangement, the radiation from the heat source is reflected, and direct heating of the thermoelectric conversion element is suppressed without passing through the heat conductor 4, so that the joining direction of the thermoelectric conversion element is By further increasing the temperature gradient at , the thermoelectric conversion efficiency of the thermoelectric conversion module 100 can be further increased. Preferably, the radiation reflector 21 may have a radiation reflectance of 90% or more. More preferably, from the viewpoint of maximizing the radiation reflection effect, the radiation reflector 21 is arranged adjacent to the high temperature side surface of the thermoelectric conversion element body 10, and the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 are connected. The joining direction ends of the direction can be arranged so as to be in contact with the two thermal conductors 4 that define the gap.
When the thermoelectric conversion module 100 does not include the substrate 6, the radiation reflector 21 is formed by the two heat conductors 4, the heat source, and the high-temperature side of the thermoelectric conversion element 10 as long as it is not in contact with the heat source. It can be arranged at any position within the space defined on all four sides.

The radiation reflector 21 is not particularly limited, and can be, for example, a sheet-like structure obtained by blending flat metal particles into a resin. In such a sheet-like structure, the flat metal particles are preferably oriented substantially parallel to the surface direction.

Furthermore, the radiation preventing body 22 can be arranged at any position within the heat insulation region 5 as long as it is not in contact with the thermoelectric conversion element body 10 and the radiation reflecting body 21 . When the thermoelectric conversion module 100 includes the radiation reflector 21 described above, the arrangement of the radiation preventing body 22 is on the higher temperature side than the radiation reflector 21 (that is, with the thermoelectric conversion element body 10 as a reference, the radiation reflector 21 position farther in the thickness direction of the thermoelectric conversion module). Then, the radiation prevention body 22 prevents radiation from the heat source and suppresses direct heating of the thermoelectric conversion element body 10 without passing through the heat conductor 4, so that the joining direction of the thermoelectric conversion element body 10 By further increasing the temperature gradient at , the thermoelectric conversion efficiency of the thermoelectric conversion module 100 can be further increased. Preferably, from the viewpoint of maximizing the radiation prevention effect, the radiation prevention body 22 is arranged adjacent to the substrate 6, and both ends of the radiation prevention body 22 in the connection direction of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 can be placed in contact with the two thermal conductors 4 that define the gap. In addition, when the thermoelectric conversion module 100 does not have the substrate 6 , the radiation preventing body 22 can be arranged directly adjacent to the heat source 200 .

The radiation preventing body 22 is not particularly limited, and is made of the same material as the radiation reflecting body 21, or, for example, a commercially available heat shielding film (manufactured by Nippon Heat Barrier Co., Ltd., "Top Heat Barrier (registered trademark) THB-WBE1" ) can be made of common low-radiation materials such as

A schematic scheme of power generation by the thermoelectric conversion module 100 is as follows. First, the heat emitted from the heat source 200 is transmitted through the heat conductor 4 to the ends of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 joined at the joint portion 3A. As a result, a temperature gradient in the joining direction of the thermoelectric conversion module 100 is generated in each of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 . An electromotive force is generated by the Seebeck effect resulting from this temperature gradient, and the thermoelectric conversion module 100 generates power. If the temperature gradient is large, the generated electromotive force will be large, and the thermoelectric conversion efficiency of the thermoelectric conversion module 100 can be improved.

The thermoelectric conversion material for forming the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 constituting the thermoelectric conversion element body 10 is not particularly limited, and may be a bismuth-tellurium-based compound, an antimony-based compound, a silicon-based Compounds, metal oxide compounds, Heusler alloy compounds, conductive polymer compounds, conductive fibers, composite materials thereof, and the like can be used. Among them, conductive fibers are preferably used, and fibrous carbon nanostructures such as carbon nanotubes (hereinafter also referred to as CNTs) are more preferably used. This is because if CNTs are used, the mechanical strength of the thermoelectric conversion module 100 of the present invention can be further improved and the weight can be reduced. Furthermore, CNTs are not particularly limited, and single-walled CNTs and/or multi-walled CNTs can be used, but the CNTs are preferably single-walled CNTs. This is because single-walled CNTs tend to have superior thermoelectric properties (Seebeck coefficient). As for single-walled carbon nanotubes, when synthesizing CNTs by a chemical vapor deposition method (CVD method) by supplying a raw material compound and a carrier gas onto a base material having a catalyst layer for CNT production on the surface, In addition, a method of dramatically improving the catalytic activity of the catalyst layer by allowing a trace amount of oxidizing agent (catalyst activating substance) to exist in the system (super-growth method; see International Publication No. 2006/011655). Manufactured CNTs can be used (hereinafter, CNTs manufactured according to such a method may be referred to as "SGCNT"). Furthermore, SGCNT has the characteristic that there are many bends. Here, although CNTs have high thermal conductivity due to electron transfer, they are also considered to have a high effect of lowering thermal conductivity due to phonon vibration. However, since SGCNTs have more bends than CNTs produced according to other general methods, they have a structure in which phonon vibrations are less likely to be amplified, and a decrease in thermal conductivity due to phonon vibrations can be suppressed. . Therefore, SGCNT can be a superior material as a thermoelectric conversion material compared to other general CNTs.

In using CNTs as a thermoelectric conversion material for forming the thermoelectric conversion element body 10, it is necessary to make the Seebeck coefficients of the CNTs forming the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 different. be. Here, CNTs have characteristics as p-type thermoelectric conversion elements as they are. Therefore, it is necessary to apply the treatment for obtaining the n-type thermoelectric conversion element 2 (hereinafter, also referred to as "n treatment") to CNT. Specifically, for example, buckypaper, which is a thin film-shaped CNT produced by a known method or commercially available, is prepared by a general method, for example, WO 2015/198980. A bucky paper that can function as the n-type thermoelectric conversion element 2 can be obtained by performing the n conversion treatment according to the method.

Here, it is preferable that each of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 has a length of 5 mm or more in the joining direction. If the length in the junction direction of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 is equal to or greater than the above lower limit, the temperature difference in the junction direction of the thermoelectric conversion elements can be further increased, and the thermoelectric conversion module can be manufactured. Thermoelectric conversion efficiency can be further increased.

Furthermore, as the thermoelectric conversion material for forming the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 that constitute the thermoelectric conversion element body 10, it is preferable to use a thermoelectric conversion material having a structure having voids inside. The thermoelectric conversion material having a structure having voids therein includes a conductive structure having a density of 0.1 g/cm ³ or less and having a fibrous network structure. Such electrically conductive structures may in particular consist of fibrous carbon nanostructures such as CNTs. If a thermoelectric conversion material having a structure having internal voids is used as the thermoelectric conversion material for forming the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2, the thermal conductivity of the thermoelectric conversion element body 10 is reduced. Therefore, the temperature gradient in the joining direction of the thermoelectric conversion element can be further increased, and the thermoelectric conversion efficiency can be further improved.

The thermoelectric conversion material having a structure having internal voids is not particularly limited, and can be formed by, for example, using a combination of fibrous carbon nanostructures containing CNTs and unexpanded expanded particles. In a thermoelectric conversion material having a structure with internal voids, the thermal conductivity in two mutually orthogonal (intersecting) directions can be different. Therefore, the direction of high thermal conductivity can be formed so as to match the thickness direction of the thermoelectric conversion module 100 . Specifically, for example, a sheet containing unexpanded foamed particles and a fibrous carbon nanostructure containing CNTs is formed, and the obtained sheet is sandwiched between molds that are open vertically or horizontally to form the foamed particles. It can be produced by foaming.

Of the junctions 3 that electrically connect the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2, the junction 3A to which the thermal conductor 4 is coupled is made of a metal having electrical and thermal conductivity. preferably. As the metal having such electrical and thermal conductivity, a metal material having an electrical conductivity (JIS K 0130:2008) of 10 S/m or more and a thermal conductivity of 10 W/m·K or more, more specifically , Ag and Cu. Among them, Ag is preferable from the viewpoint that there is a paste-like material that is easily available, that the cost of the process can be reduced, and that the ease of the process can be imparted. If the joint portion 3 contains a metal material having electrical and thermal conductivity, the heat transfer efficiency between the joint portion 3A and the heat conductor 4 is increased, and the thermoelectric conversion efficiency of the thermoelectric conversion module can be further improved. . Furthermore, it is preferable that the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 are directly connected at the joint portion 3B to which the heat conductor 4 is not connected. In the thermoelectric conversion module, if the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 are directly bonded at the bonding portion 3B where the heat conductor 4 is not bonded, the thermoelectric conversion element body 10 in the bonding direction The temperature difference can be further increased, and the thermoelectric conversion efficiency of the thermoelectric conversion module 100 can be further increased.
In addition, in this specification, "thermal conductivity" is a value that can be measured using, for example, a laser flash method for a measurement object such as a thermal conductor.

For example, the joint portion 3A can be formed by connecting the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 using a paste-like resin material containing Ag as a conductive material. The resin material is not particularly limited, and general resins such as (meth) acrylic resins, epoxy resins, fluorine resins, silicone resins, olefin resins, polyamide resins, and polyimide resins. materials can be used. Preferably, as the resin material, a polyimide-based resin, which has high flexibility and high heat resistance, is used. In addition, in this specification, (meth)acryl means "acryl" or "methacryl".

The thermal conductor 4 connected to the thermoelectric conversion element body 10 is coupled to the joint 3 as described above. Here, the heat conductors 4 are preferably arranged such that the heat insulating regions 5 adjacent to the heat conductors 4 communicate with each other. This is because the air circulates between the heat insulating regions 5, so that the heat insulating properties of the heat insulating regions 5 can be further improved, and the temperature gradient in the joining direction of the thermoelectric conversion element bodies 10 can be increased. Furthermore, in the heat conductor 4, the heat insulating regions 5 adjacent to the heat conductor 4 communicate with each other, and each of the plurality of heat insulating regions 5 communicates directly or indirectly with the atmosphere outside the thermoelectric conversion module 100. It is preferably arranged to This is because the temperature gradient in the joining direction of the thermoelectric conversion element body 10 can be further increased by further increasing the heat insulating property of the heat insulating region 5 .

The thermal conductor 4 is not particularly limited, and is made of a thermally conductive material including a thermally conductive inorganic material such as a metal material similar to the joint 3A and a thermally conductive organic material such as a thermally conductive resin. can be formed. Among them, Al is preferable from the viewpoint of lightness. The thermal conductivity of the heat conductor 4 is preferably 10 W/m·K or more, more preferably 50 W/m·K or more, further preferably 100 W/m·K or more, and 200 W/m·K or more. It is particularly preferable that it is m·K or more. Moreover, the heat conductor 4 preferably has a length in the thickness direction of the thermoelectric conversion module 100 of 1 mm or more. This is because the temperature gradient in the joining direction of the thermoelectric conversion element body 10 can be further increased. Furthermore, the heat conductor 4 is in contact with the thermoelectric conversion element body 10 in a region of ⅕ or less of the joint direction length of each of the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2, and the joint portion 3A. is preferred.

Furthermore, the thermal conductor 4 may be an anisotropic thermal conductor. In an anisotropic thermal conductor, the thermal conductivity in the thickness direction of the thermoelectric conversion module 100 is higher than the thermal conductivity in the transverse direction with respect to the thickness direction. If the thermal conductor 4 is an anisotropic thermal conductor with high thermal conductivity in the thickness direction, the loss that can occur when the thermal conductor 4 conducts heat is reduced, and the thermoelectric conversion efficiency of the thermoelectric conversion module 100 is improved. can be further improved. When the thermal conductor 4 is an anisotropic thermal conductor, the thermal conductivity of the anisotropic thermal conductor in the thickness direction is preferably 10 W/m·K or more, and 50 W/m ·K or more, more preferably 100 W/m·K or more, and particularly preferably 200 W/m·K or more.

The anisotropic thermal conductor is not particularly limited, and is formed using, for example, a graphite sheet, an organic anisotropic thermal conductive material such as CNT, and an inorganic anisotropic thermal conductive material such as flat metal particles. can do. The flat metal particles mean, for example, flat metal particles having an aspect ratio of 3 or more. Preferably, an organic anisotropic thermally conductive material is used from the viewpoint of imparting flexibility to the thermoelectric conversion element body 10 and reducing its weight. Furthermore, from the viewpoint of further improving the thermoelectric conversion efficiency of the thermoelectric conversion module 100, it is preferable to form the anisotropic thermal conductor forming the thermal conductor 4 using CNT.
The anisotropic heat conductor is not particularly limited, and may be formed by using these anisotropic heat conductive materials together with a general resin material that can also be used to form the joint 3. can be done. The anisotropic thermal conductor includes a coating process, a pressurizing process, etc., so that the direction of high thermal conductivity of the anisotropic thermal conductive material matches the thickness direction of the thermoelectric conversion module 100. It can be produced by a known production method.

Furthermore, the film-like thermoelectric conversion element body 10 can have at least one thermoelectric conversion element substrate that supports the thermoelectric conversion element body 10 . In FIG. 1, the thermoelectric conversion element 10 is sandwiched from both sides by a high temperature side thermoelectric conversion element substrate 11 and a low temperature side thermoelectric conversion element substrate 12 . If the thermoelectric conversion element bodies 10 are supported by at least one thermoelectric conversion element substrate, the mechanical strength of the thermoelectric conversion module 100 can be further improved. Furthermore, if the high-temperature-side thermoelectric conversion element substrate 11 and the low-temperature-side thermoelectric conversion element substrate 12 have at least one air hole, the air permeability of the heat insulating region 5 is improved, and the heat insulating property of the heat insulating region 5 is improved. can be improved. Therefore, the temperature difference in the connecting direction of the thermoelectric conversion element bodies 10 can be further increased.

The high-temperature-side thermoelectric conversion element substrate 11 and the low-temperature-side thermoelectric conversion element substrate 12 are not particularly limited, and may be films formed of a resin material such as polyimide that is highly heat-resistant and flexible.

Further, the air vents of the high-temperature side thermoelectric conversion element substrate 11 and the low-temperature side thermoelectric conversion element substrate 12 are not particularly limited, and are along the joining direction of the p-type thermoelectric conversion elements 1 and the n-type thermoelectric conversion elements 2. , may be equally spaced.

Furthermore, as shown in FIG. 1 , the thermoelectric conversion module 100 may have a substrate 6 connected to the thermoelectric conversion element body 10 via a heat conductor 4 . The mechanical strength of the thermoelectric conversion module 100 can be improved by providing at least one substrate 6 that is connected to the thermoelectric conversion element body 10 via the thermal conductor 4 . Such at least one substrate 6 may also serve to protect the components inside the module from the external environment.

The substrate 6 can be a resin substrate or a metal substrate. Examples of resin substrates include so-called flexible substrates, which are substrates containing a resin material having flexibility. Examples of such a flexible substrate include a substrate formed using a resin having low thermal conductivity and excellent heat resistance and flexibility. As with the thermoelectric conversion element substrate 12, a substrate made of polyimide as a forming material can be mentioned. Moreover, examples of metal substrates include substrates containing metal materials with high thermal conductivity such as aluminum, copper, and silver. The resin substrate and the metal substrate can be used individually, but both can be laminated and used together.

When a resin substrate is adopted as the substrate 6, flexibility can be imparted to the thermoelectric conversion module 100, and ease of installation of the thermoelectric conversion module can be improved. Since the installation place of the thermoelectric conversion module is not necessarily a flat place, if the thermoelectric conversion module can be given flexibility, the thermoelectric conversion module can be freely deformed according to the shape of the installation place, and the power generation efficiency can be improved. can be raised.
On the other hand, when a metal substrate is employed as the substrate 6, the temperature gradient in the joining direction of the thermoelectric conversion elements can be further increased, and the thermoelectric conversion efficiency can be further increased.

Furthermore, as the substrate 6, an anisotropic thermally conductive substrate formed using the same anisotropic thermally conductive material as the thermal conductor 4 can be used. In an anisotropic thermally conductive substrate, the thermal conductivity in the direction transverse to the thickness direction of the substrate is higher than the thermal conductivity in the thickness direction of the substrate. Therefore, if at least the substrate 6 is an anisotropic thermally conductive substrate with high thermal conductivity, the heat collection efficiency from the heat source is increased, and the amount of heat input to the thermoelectric conversion element 10 via the thermal conductor 4 is increased. can be made Thereby, the temperature gradient in the joining direction of the thermoelectric conversion element body 10 can be further increased, and the thermoelectric conversion efficiency can be further improved. When the substrate 6 is an anisotropic thermally conductive substrate, it is preferable to use an organic anisotropic thermally conductive material, similar to the thermal conductor 4, from the viewpoint of flexibility and weight reduction.

Moreover, the thickness of the thermoelectric conversion module 100 including the thermoelectric conversion element bodies 10 is preferably 10 mm or less, more preferably 6 mm or less. This is because the ease of attachment of the thermoelectric conversion module 100 can be improved.

FIG. 2 shows a plan view of another example of the schematic structure of the thermoelectric conversion module of the present invention. FIG. 2 shows a plan view of the thermoelectric conversion module 101 viewed from the low temperature side. In the thermoelectric conversion module 101, continuous junctions of the p-type thermoelectric conversion elements 1 and the n-type thermoelectric conversion elements 2 forming the thermoelectric conversion element body 10' are arranged in a meandering manner. As shown in FIG. 2, the "serpentine arrangement" means that a continuous assembly of a plurality of p-type thermoelectric conversion elements 1 and n-type thermoelectric conversion elements 2 is arranged in a shape as if it were folded within a section of a predetermined area. means a mode in which If the continuous junction body of a plurality of thermoelectric conversion elements constituting the thermoelectric conversion element body 10' is arranged in a meandering manner, a large number of thermoelectric conversion elements can be efficiently integrated and arranged in a limited space, and thermoelectric conversion can be achieved. The thermoelectric conversion efficiency of the conversion module can be further enhanced.

In FIG. 2, thermoelectric conversion elements of different conductivity types (that is, n-type thermoelectric conversion elements to p-type thermoelectric conversion elements, and vice versa) are connected by conductive members 30 at both ends of the folded shape. exemplify one embodiment. The conductive member 30 can be made of a metal material such as Ag and Cu, or a carbon-based material such as a graphite sheet and CNT.

With respect to a continuous junction of a plurality of p-type thermoelectric conversion elements 1 and n-type thermoelectric conversion elements 2 arranged in a meandering manner, the longitudinal direction of the rectangular heat conductor 4 is the p-type thermoelectric conversion elements 1 and n-type thermoelectric conversion elements It is oriented in a direction perpendicular to the bonding direction of the element 2 (within the plane shown). The same heat conductor 4 is coupled to a plurality of joints 3A having the same joint direction position. With this arrangement, both flexibility in the joining direction and strength in the direction perpendicular to the joining direction can be achieved. Moreover, according to this arrangement, it is possible to reduce the temperature difference between the plurality of joints 3A to which the same thermal conductor 4 is connected, and to make the electromotive force of the thermoelectric conversion module uniform. If the temperature difference becomes non-uniform depending on the location of the thermoelectric conversion element 10', the electromotive force (voltage) will be uneven, resulting in a difference in the current value obtained depending on the part of the thermoelectric conversion element 10'. Since the thermoelectric conversion module is made by connecting each element in series, if there is a difference in the current value, the lowest current value is specified, which may result in a decrease in the power generation of the thermoelectric conversion module. .
In this specification, the term “perpendicular to the bonding direction” means that the direction perpendicular to the bonding direction or substantially orthogonal to the bonding direction (the angle formed with the bonding direction is 90°) in the plane of the thermoelectric conversion element body. within ±5°).
In addition, in this specification, the term "rectangular" means a shape in which all four corners such as squares and rectangles are 90°, and any one or more corners are C-chamfered or R-chamfered. Also includes

Further, the thermoelectric conversion element 10' is sandwiched between a high temperature side thermoelectric conversion element substrate 11 and a low temperature side thermoelectric conversion element substrate. In FIG. 2, illustration of the low temperature side thermoelectric conversion element substrate is omitted for clarity. The conductive member 30 can also be sandwiched between the high temperature side thermoelectric conversion element substrate 11 and the low temperature side thermoelectric conversion element substrate (not shown).

Further, the high temperature side thermoelectric conversion element substrate 11 has a plurality of ventilation holes 31 arranged at predetermined intervals along the joining direction of the p-type thermoelectric conversion elements 1 and the n-type thermoelectric conversion elements 2 . A low temperature side thermoelectric conversion element substrate (not shown) may also have a plurality of vents at corresponding positions. The ventilation hole 31 allows the heat insulating region 5 as shown in FIG.

In the thermoelectric conversion module 101, conductive wires 40 are connected to both ends of the thermoelectric conversion element body 10', and electric power generated by the thermoelectric conversion element body 10' can be taken out.

FIG. 3 is a plan view of still another example of the schematic structure of the thermoelectric conversion module of the present invention. The thermoelectric conversion module 102 shown in FIG. 3 has the same structure except that the shape and arrangement of the heat conductors 4' are different from those of the heat conductors 4 of the thermoelectric conversion module 103 shown in FIG. As shown in FIG. 3, in the thermoelectric conversion module 102, the length of the heat conductor 4' in the longitudinal direction substantially matches the length of the P/n-type thermoelectric conversion elements 1/2 in the direction perpendicular to the joining direction. The plurality of heat conductors 4' are not connected to each other in the direction perpendicular to the joining direction (within the plane shown), and the heat conductors 4' are spaced apart from each other. there is The flexibility of the thermoelectric conversion module can be further enhanced if the plurality of heat conductors coupled to the meanderingly arranged continuous joints are spaced apart from each other.

FIG. 4 is a plan view of still another example of the schematic structure of the thermoelectric conversion module of the present invention. In FIG. 4, in the thermoelectric conversion element body 10'', each p-type thermoelectric conversion element 1' or n-type thermoelectric conversion element 2' arranged at each end in the joining direction is to be joined at each end. It forms an end junction 3C directly joined to another n-type thermoelectric conversion element 2' or p-type thermoelectric conversion element 1' having a different conductivity type. The end joint portion 3C is formed by a p-type thermoelectric conversion element 1' and an n-type thermoelectric conversion element 2' having L-shaped or inverted L-shaped ends. In this way, if the thermoelectric conversion elements having end shapes deformed into L-shapes or inverted L-shapes are directly bonded to each other at both ends in the bonding direction of the continuous bonded bodies arranged in a meandering manner, thermoelectric conversion can be achieved. The flexibility of the conversion module can be further enhanced.
In this specification, the term “L-shaped or inverted L-shaped” means a shape having a constituent part whose axis can be in a direction intersecting the joining direction, and the joining direction and the intersecting direction are not necessarily orthogonal. It doesn't have to be.
4, the structure of the thermoelectric conversion module 103 is the same as that of the thermoelectric conversion module 103 shown in FIG. Same as conversion module 101 .

In FIG. 4, both the p-type thermoelectric conversion element 1' and the n-type thermoelectric conversion element 2' have L-shaped or inverted L-shaped portions at the ends, and these L-shaped portions and inverted L-shaped portions The L-shaped portion is illustrated as forming the end joint 3C. However, the shapes of the p-type thermoelectric conversion element 1' and the n-type thermoelectric conversion element 2' are not limited to such shapes. Only one of them may have an L-shape or an inverted L-shape, and form an end junction 3C with the other thermoelectric conversion element having a normal rectangular shape. Also, the corners forming the L-shaped or inverted L-shaped portion may be C-chamfered or R-chamfered.

As described above, according to the present invention, it is possible to provide a thermoelectric conversion module that achieves both thermoelectric conversion efficiency and flexibility.

1, 1' p-type thermoelectric conversion elements 2, 2' n-type thermoelectric conversion elements 3A, 3B junction 3C end junctions 4, 4' heat conductor 5 heat insulating region 6 substrate 10, 10', 10'' thermoelectric conversion Element body 11 High temperature side thermoelectric conversion element substrate 12 Low temperature side thermoelectric conversion element substrate 21 Radiation reflector 22 Radiation prevention body 30 Conductive member 31 Air vent 40 Conductive wires 100 to 103 Thermoelectric conversion module 200 Heat source

Claims (10)

A thermoelectric conversion module that converts heat from a heat source into electric power,
a film-like thermoelectric conversion element body having a p-type thermoelectric conversion element and an n-type thermoelectric conversion element bonded along a bonding direction that is one in-plane direction;
One surface of the thermoelectric conversion element body is a first surface that receives heat from a heat source, and the other surface is a second surface, and the p-type thermoelectric conversion element and the n-type thermoelectric conversion are performed only on the first surface. a thermal conductor coupled to the junction of the element;
a heat insulating region adjacent to both sides of the heat conductor in the joining direction;
with
The thermoelectric conversion module , wherein the heat insulating region is air or void . The film-like thermoelectric conversion element body is formed by continuously joining at least two pairs of p-type thermoelectric conversion elements and n-type thermoelectric conversion elements,
the thermal conductor is coupled to every other pair of junctions of the at least two pairs of the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements;
wherein the joint to which the thermal conductor is bonded comprises a metal material having electrical and thermal conductivity;
The thermoelectric conversion module according to claim 1. 3. The thermoelectric conversion module according to claim 2, wherein, of the plurality of joints, a joint to which the heat conductor is not coupled is formed by directly joining the p-type thermoelectric conversion element and the n-type thermoelectric conversion element. The thermoelectric device according to any one of claims 1 to 3, wherein said film-like thermoelectric conversion element has at least one thermoelectric conversion element substrate, and said thermoelectric conversion element substrate has at least one air vent. conversion module. The thermoelectric conversion module according to any one of claims 1 to 4, wherein said film-like thermoelectric conversion element includes a fibrous carbon nanostructure . 6. The thermoelectric conversion module according to any one of claims 1 to 5, comprising a radiation reflector and/or a radiation blocker in said heat insulating region. 7. The thermoelectric conversion module according to any one of claims 2 to 6, wherein a continuous assembly of said p-type thermoelectric conversion elements and said n-type thermoelectric conversion elements constituting said film-like thermoelectric conversion element body is arranged in a meandering manner. . 8. The thermoelectric conversion according to claim 7, wherein a plurality of thermal conductors connected to said continuous joints arranged in a meandering manner are connected to each other in a direction perpendicular to said joining direction within said plane. module. 8. The thermoelectric conversion module according to claim 7, wherein each of a plurality of heat conductors coupled to said meanderingly arranged continuous joint is spaced apart from other heat conductors. Each p-type thermoelectric conversion element or n-type thermoelectric conversion element arranged at each end in the joining direction of the continuous joined body arranged in a meandering manner has different conductivity types to be joined at each end. The p-type thermoelectric conversion element has an end joint directly joined to another n-type thermoelectric conversion element or a p-type thermoelectric conversion element, and the end joint has an L-shaped or inverted L-shaped end. 10. The thermoelectric conversion module according to any one of claims 7 to 9, comprising a conversion element and/or said n-type thermoelectric conversion element.

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