JP6492210B1 - Thermal rectifying substrate and thermoelectric generator - Google Patents

Abstract

The present invention provides a thermal rectifying substrate and a thermoelectric generator that are easier to manufacture.
A heat rectifying substrate (2A) includes a plurality of thin film PTC regions (20) and a plurality of thin film NTC regions (10). In the plan view and the cross sectional view, the plurality of PTC regions 20 and the plurality of NTC regions 10 are alternately arranged. The PTC region 20 includes a P-side substrate and a plurality of P-side thermally conductive particles disposed in the P-side substrate. The plurality of NTC regions include an N-side substrate, a plurality of N-side thermally conductive particles and a plurality of heat-shrinkable particles disposed in the N-side substrate, and the plurality of heat-shrinkable particles It contracts with it.
[Selected figure] Figure 1

Description

  The present invention relates to a thermal rectifying substrate and a thermoelectric power generation device.

  DESCRIPTION OF RELATED ART Conventionally, as it shows by following patent document 1, the thermoelectric-generation apparatus which can convert thermal energy into an electrical energy directly is known. The thermoelectric generator includes a thermoelectric conversion module and a heat rectifying substrate. The heat rectifying substrate includes a heat conductive resin A (good heat conductive portion) having a heat conductive filler, and a heat conductive resin B (heat insulating portion) having a heat conductivity lower than that of the heat conductive resin A. . The good heat conducting parts and the heat insulating parts are alternately arranged. The thermoelectric conversion module is configured to generate power in accordance with the temperature difference between the good thermal conductivity portion and the thermal insulation portion.

International Publication No. 2014/148494

  As in Patent Document 1, when the good thermal conductivity part and the thermal insulation part are alternately arranged, one of the good thermal conductivity part and the thermal insulation part is formed using a metal mask, a photomask, screen printing or the like. After that, a complicated manufacturing process is required, such as forming the other in the gap.

  The present invention has been made in consideration of such circumstances, and it is an object of the present invention to provide a thermal rectifying substrate and a thermoelectric power generator which are easier to manufacture.

  In order to solve the above problems, a thermal rectifying substrate according to a first aspect of the present invention includes a plurality of PTC regions and a plurality of NTC regions, and in plan view and cross sectional view, the plurality of PTC regions and the above A plurality of NTC regions are arranged alternately, and the plurality of PTC regions include a P-side substrate formed of a resin and a plurality of P-side thermally conductive particles disposed in the P-side substrate. The plurality of NTC regions include an N-side base formed of a resin, a plurality of N-side thermally conductive particles and a plurality of heat-shrinkable particles disposed in the N-side base, The plurality of P-side thermally conductive particles have a thermal conductivity larger than that of the P-side substrate, and the plurality of N-side thermally conductive particles have a thermal conductivity larger than that of the N-side substrate, and the plurality of thermal contractions The particles shrink as the temperature rises.

According to the first aspect, the heat-shrinkable particles contained in the NTC region shrink as the temperature rises. Therefore, the distance between the N-side heat conductive particles around the heat-shrinkable particles decreases, and the thermal conductivity in the NTC region increases. On the other hand, in the PTC region, the P-side base material expands as the temperature rises, and the distance between the P-side thermally conductive particles increases. For this reason, the thermal conductivity of the PTC region is reduced. By alternately arranging such PTC regions and NTC regions in plan view and cross-sectional view, when one surface of the thermal rectifying substrate is heated, a temperature difference can be generated in the other surface.
And since the heat-rectifying substrate of the said aspect is mainly formed about the P side base material and N side base material which are resin, manufacture is comparatively easy and it can give flexibility as a whole. it can. If the heat rectifying substrate has flexibility, it can be attached to a heat source of complicated shape, and the heat rectifying substrate can be applied to a wider range of applications.

  Here, in a plan view, the plurality of PTC regions and the plurality of NTC regions are formed in a strip shape long in a first direction, and are alternately arranged in a second direction orthogonal to the first direction. It is also good.

  In this case, for example, a film to be a PTC region and a film to be an NTC region are separately formed, and the respective films are cut and combined with each other, so that the thermally rectifying substrate can be relatively easily manufactured.

  In addition, in a plan view, the plurality of PTC regions and the plurality of NTC regions may be alternately arranged in both the first direction and a second direction orthogonal to the first direction.

  In this case, for example, by separately forming a band-shaped film to be a PTC region and a band-shaped film to be an NTC region and knitting the band-shaped films, the thermally rectifying substrate can be relatively easily manufactured.

  Further, a thermoelectric power generation device according to a second aspect of the present invention includes the above-described thermal rectifying substrate, and a thermoelectric conversion module provided on the thermal rectifying substrate, the thermoelectric conversion module comprising at least one A P-type thermoelectric element, at least one N-type thermoelectric element, and a plurality of electrodes, wherein the P-type thermoelectric element and the N-type thermoelectric element are connected by the electrode, and the P-type thermoelectric element and The electrodes are provided at both ends of the N-type thermoelectric element, and in plan view, the P-type thermoelectric element and the N-type thermoelectric element cross the boundary between the PTC region and the NTC region. It is arranged.

  According to the second aspect, for example, when heat is applied to the lower surface of the heat rectifying substrate, a temperature difference is generated in the upper surface of the heat rectifying substrate. Specifically, the temperature of the PTC region at the top surface is higher than the temperature of the NTC region at the top surface. Then, since the P-type thermoelectric element and the N-type thermoelectric element are disposed across the boundary between the NTC region and the PTC region, thermal energy is converted to electrical energy by the temperature difference between the PTC region and the NTC region. It is possible to

  According to the above aspect of the present invention, it is possible to provide a thermal rectifying substrate and a thermoelectric power generator that are easier to manufacture.

It is a top view of the thermoelectric-generation device concerning a 1st embodiment. It is an II-II cross section arrow line view of FIG. (A) is sectional drawing which shows schematic structure of NTC area | region. (B) is sectional drawing which shows schematic structure of a PTC area | region. It is a schematic diagram which shows the example of the heat conductive particle of FIG. 3 (a), (b). It is a figure which shows an example of the manufacturing method of NTC area | region (NTC film | membrane) of FIG. It is a figure which shows an example of the manufacturing method of the heat | fever rectifying substrate which concerns on 1st Embodiment. (A) is a figure which shows the relationship of temperature and heat conductivity about the PTC area | region of FIG. (B) is a figure which shows the relationship of temperature and heat conductivity about the NTC area | region of FIG. (A) is the schematic at the time of providing a heat source in the N side surface. (B) is the schematic at the time of providing a heat source in the P side surface. (A) and (b) are the figures explaining the difference in the heat conductivity according to the direction of a heat flow. It is a top view of the thermoelectric-generation device concerning a 2nd embodiment. It is a figure which shows an example of the manufacturing method of the heat | fever rectifying substrate which concerns on 2nd Embodiment. It is a figure explaining the heat | fever rectifying substrate which concerns on an Example. It is a graph explaining the thermal characteristic of the heat rectification substrate concerning an example.

First Embodiment
Hereinafter, the thermal rectifying substrate and the thermoelectric power generation device of the first embodiment will be described based on the drawings.
As shown in FIG. 1, the thermoelectric power generation device 1A includes a thermally rectifying substrate 2A and a thermoelectric conversion module 3 provided on the thermally rectifying substrate 2A.

(Direction definition)
Here, in the present embodiment, an XYZ orthogonal coordinate system is set, and the positional relationship of each configuration will be described. The Z direction is the thickness direction of the heat rectifying substrate 2A. The X direction is a direction orthogonal to the Z direction. The Y direction is a direction orthogonal to both the Z direction and the X direction.
Hereinafter, each direction is referred to as a first direction X, a second direction Y, and an up-down direction Z. Further, in the vertical direction Z, the side of the heat rectifying substrate 2A is referred to as the lower side, and the side of the thermoelectric conversion module 3 is referred to as the upper side. Also, viewing in the vertical direction Z is referred to as plan view, and viewing in a cross section along the vertical direction Z is referred to as cross-sectional view.

(Thermal rectifying substrate)
As shown in FIG. 2, the heat rectifying substrate 2A has a two-layer structure having an upper layer portion 2a and a lower layer portion 2b. The upper layer portion 2a and the lower layer portion 2b are formed in a thin film shape, and the upper layer portion 2a and the lower layer portion 2b are in close contact and integrated. The upper surface of the thermal rectifying substrate 2A is the upper surface 2a1 of the upper layer portion 2a, and the lower surface of the thermal rectifying substrate 2A is the lower surface 2b1 of the lower layer portion 2b.
The upper surface 2 a 1 is covered by the insulator 4 together with the thermoelectric conversion module 3. The insulator 4 may be omitted. Illustration of the insulator 4 is omitted in FIG.

  The upper layer portion 2a and the lower layer portion 2b respectively include a plurality of thin film NTC regions 10 and a plurality of thin film PTC regions 20. Below the NTC region 10 (upper NTC region) included in the upper layer portion 2a, a PTC region 20 (lower PTC region) included in the lower layer portion 2b is disposed. Below the PTC region 20 (upper PTC region) included in the upper layer portion 2a, an NTC region 10 (lower NTC region) included in the lower layer portion 2b is disposed. Further, as shown in FIG. 1, the NTC regions 10 and the PTC regions 20 are alternately arranged in the second direction Y in a plan view as viewed from the vertical direction Z.

According to the above configuration, thermal rectifying substrate 2A is provided with a plurality of PTC regions 20 and a plurality of NTC regions 10, and a plurality of PTC regions 20 and a plurality of NTC regions 10 are alternately arranged in plan view and cross sectional view. There is.
Further, in the present embodiment, the NTC region 10 and the PTC region 20 are formed in a strip shape long in the first direction X.

  NTC region 10 and PTC region 20 are each formed in a film shape having a first surface and a second surface. NTC region 10 has NTC characteristics, and PTC region 20 has PTC characteristics. Here, the PTC characteristic is a characteristic in which a physical property value (herein, thermal resistance or electric resistance) changes with a positive coefficient due to temperature rise. On the contrary to the NTC characteristic, the property value (same as above) changes with a negative coefficient due to temperature rise.

  The NTC region 10 and the PTC region 20 are composed of a composite film in which an organic material and an inorganic material are combined. The heat rectifying substrate 2A is in the form of a thin film because it is formed by overlapping the NTC region 10 and the PTC region 20. In the present embodiment, the thermal rectification is realized by changing the state of the heat conduction path existing inside the NTC region 10 and the PTC region 20 depending on the direction of heat flow. The details will be described below.

(NTC area)
FIG. 3A is an enlarged view of the NTC region 10 of FIG. As shown in FIG. 3A, the NTC region 10 has an N-side substrate 11, a plurality of N-side thermally conductive particles 12, and a plurality of heat-shrinkable particles 13. The N-side substrate 11 contains a first material 11 a (N-side first material) and a second material 11 b (N-side second material). The N-side thermally conductive particles 12 and the heat-shrinkable particles 13 are kneaded in the N-side substrate 11.

  In the cross section along the thickness direction (vertical direction Z) of the NTC region 10, a plurality of crystalline layers and a plurality of non-crystalline layers arranged alternately are formed in the NTC region 10. The crystalline layer is mainly composed of the first material 11a, and the non-crystalline layer is mainly composed of the second material 11b. The crystalline layer and the non-crystalline layer extend in the thickness direction of the NTC region 10. The N-side thermally conductive particles 12 and the thermally shrinkable particles 13 are mainly present in the non-crystalline layer (second material 11 b) of the NTC region 10. The N-side thermally conductive particles 12 are arranged in a straight line in the thickness direction from the first surface to the second surface of the NTC region 10. In addition, this line does not have to be in a straight line, and may be branched on the way.

(PTC area)
FIG. 3B is an enlarged view of the PTC region 20 viewed in cross section. As shown in FIG. 3 (b), the PTC region 20 includes the P-side base 21 and the P-side heat conductive particles 22. The P-side substrate 21 contains a first material 21 a (P-side first material) and a second material 21 b (P-side second material). The P-side thermally conductive particles 22 are kneaded in the P-side substrate 21.

  In the cross section along the thickness direction of the PTC region 20, the PTC region 20 is formed with a plurality of crystalline layers and a plurality of non-crystalline layers alternately arranged. The crystalline layer is mainly composed of the first material 21a, and the non-crystalline layer is mainly composed of the second material 21b. The crystalline layer and the non-crystalline layer extend in the thickness direction of the PTC region 20. The P-side thermally conductive particles 22 are mainly present in the non-crystalline layer (second material 21 b) of the PTC region 20. The P-side thermally conductive particles 22 are arranged in a straight line in the thickness direction of the PTC region 20. In addition, this line does not have to be in a straight line, and may be branched on the way.

(Heat conduction particles)
The heat conductive particles 12, 22 are formed of a material having a thermal conductivity higher than that of the base materials 11, 21. As a structure of the heat conductive particles 12 and 22, a thing as shown in FIG. 4 is mentioned. In the example of FIG. 4, the heat conductive particles 12 and 22 have conductive magnetic particles M and a coating C covering the magnetic particles M.

  The magnetic particles M are made of, for example, a magnetic material containing one or more of nickel (Ni), cobalt (Co), and iron (Fe). The magnetic material is preferably a metal. In particular, Ni or a Ni alloy is a magnetic material excellent in conductivity and corrosion resistance, and thus is suitable as a material of the magnetic particles M.

  As shown in FIG. 4, a plurality of protrusions may be formed on the outer surface of the particle body of the magnetic particles M. The projections are preferably tapered, that is, they have a shape in which the width decreases with distance from the outer surface (for example, a pyramid such as a polygonal pyramid or a cone). When the magnetic particles M have projections, the number of contact points when the N-side thermally conductive particles 12 or P-side thermally conductive particles 22 come into contact with each other increases. This enhances the thermal conductivity and conductivity of the thermal conduction path in the NTC region 10 or PTC region 20. In addition, the particle | grains which have the several processus | protrusion of sharp taper shape are called "spiky particle | grains." The magnetic particles M are more preferably spike-like particles.

The magnetic particles M have, for example, a plurality of sharp projections (usually 10 to 500) formed on the surface of one spherical particle body. The height of each protrusion is approximately 1/3 to 1/500 with respect to the particle size of the particle body. The heat conductive particles 12 and 22 are obtained, for example, by using a carbonyl metal powder (nickel carbonyl having a purity of 99.99%) as a raw material, according to a reaction of Ni (CO) ₄ → Ni + 4CO (see JP-A-5-47503). .

  The average particle diameter of the magnetic particles M is, for example, 0.2 to 10 μm (preferably 1 to 3 μm). If the particle size of the magnetic particles M is smaller than 0.2 μm, the heat conduction particles 12 and 22 can be obtained because the magnetic force acting on the heat conduction particles 12 and 22 is small even when a magnetic field is applied in the manufacturing process of the heat rectifying substrate 2A. Is difficult to move. In addition, when the particle size of the magnetic particles M is larger than 10 μm, the heat conductive particles 12 and 22 can be formed, for example, by increasing the flow resistance in the liquid substrates 11 and 21 even if a magnetic field is applied in the manufacturing process. It becomes difficult to move. On the other hand, if the average particle diameter of the magnetic particles M is in the above range, the heat conductive particles 12 and 22 easily move in the magnetic field, and it becomes easy to take an arrangement in a row in the film thickness direction.

  The average particle diameter of the magnetic particles M can be measured, for example, by a particle size distribution measuring device based on a laser diffraction scattering method. As the average particle size, for example, a 50% cumulative particle size (mass basis or volume basis), a mode particle size or the like can be adopted. The average particle size may be an average of measurement values of a sufficient number (for example, 100 or more) of particles based on an image obtained by observing the particles. The image of the particle is, for example, an observation image obtained using an optical microscope, an electron microscope, or the like. As the particle diameter of non-spherical particles, for example, an average value of the longest diameter and the shortest diameter in the observation image may be adopted.

  The coating C covers the outer surface of the magnetic particles M. The coating C is formed of, for example, a carbon material. Examples of the carbon material include graphene, carbon nanotubes, carbon black and the like. In particular, graphene which is a material excellent in conductivity and durability is suitable as the material of the coating C. The thickness of the coating C is, for example, 1 to 100 nm (preferably 10 to 20 nm).

  The coating C has a function of protecting the magnetic particles M. For example, when the heat-rectifying substrate 2A comes in contact with a liquid or the like, the coating C can protect the magnetic particles M from the liquid. The coating C also has a function of increasing the contact area between the heat conductive particles 12 and 22 and reducing the thermal resistance and the electrical resistance of the NTC region 10 or the PTC region 20.

The average particle diameter of the heat conductive particles 12 and 22 is, for example, 0.2 to 10 μm (preferably 1 to 3 μm). The average particle size and the maximum particle size of the heat transfer particles 12, 22 are smaller than the thickness of the NTC region 10 or the PTC region 20. The thermally conductive particles 12 and 22 may be compressively strained in the thickness direction of the NTC region 10 or the PTC region 20.
The materials, structures, and the like of the N-side thermally conductive particles 12 and the P-side thermally conductive particles 22 may be the same or different.

(Heat shrinking particles)
The heat-shrinkable particles 13 are formed of a material having a negative coefficient of thermal expansion, and contract as the temperature rises. Examples of the material of the heat-shrinkable particles 13 include ceramics. More specifically, a manganese nitride represented by Mn ₃ XN (X: Zn, Cu, Ge, Ga, Sn, etc.) can be used as the heat shrinkable particle 13. X may be one of Zn (zinc), Cu (copper), Ge (germanium), Ga (gallium), Sn (tin) or the like, or two or more of them. It is also good. For example, a manganese nitride represented by Mn ₃ Zn _x Cu _Y N may be used as the heat shrinkable particle 13.
The heat-shrinkable particles 13 are disposed mainly in the second material 11 b of the N-side substrate 11 together with the N-side heat conductive particles 12.
Although not shown, the heat-shrinkable particles 13 may also be provided with the same coating C as the heat-conductive particles 12 and 22. In this case, the heat shrinkable particles 13 can be protected by the coating C.

(1st material)
The first materials 11a and 21a are crystalline resin materials. The first materials 11a and 21a are insulating materials. The first materials 11a and 21a preferably have a thermal expansion coefficient higher than that of the second materials 11b and 21b. The first materials 11a and 21a are preferably liquid curable materials (for example, thermoplastic materials).
Polyethylene can be suitably used as the first materials 11a and 21a. The embrittlement temperature of polyethylene is −80 to −20 ° C., and the glass transition temperature is −20 to −120 ° C.

  As the first materials 11a and 21a, for example, a polyolefin resin, a polyamide resin, a polyacetal resin, a polyester resin, a fluorine resin or the like may be used. Among the first materials 11a and 21a, one of them may be used alone, or two or more may be mixed and used. As a polyolefin resin, for example, high density polyethylene (melting point 120 to 140 ° C.), medium density polyethylene, low density polyethylene (melting point 95 to 130 ° C.), ethylene propylene diene copolymer (EPDM), ethylene / vinyl acetate copolymer Polyethylenes such as (EVA); polypropylenes such as isotactic polypropylene and syndiotactic polypropylene (melting point: 100 to 140 ° C.); polybutene and the like. Examples of polyamide resins include nylon 6, nylon 8, nylon 11, nylon 66, nylon 610 and the like.

(2nd material)
The second materials 11 b and 21 b are non-crystalline resin materials. The second materials 11 b and 21 b are insulating materials.
For example, paraffins can be suitably used as the second materials 11 b and 21 b. A polystyrene resin, non-crystalline polyethylene or the like may be used as the second material 11 b and 21 b. Among the second materials 11b and 21b, one of them may be used alone, or two or more may be mixed and used.
The second materials 11 b and 21 b are preferably liquid curable materials (for example, thermoplastic materials). The second materials 11 b and 21 b preferably have a lower molecular weight than the first materials 11 a and 21 a.

  The melting point of the second material 11b, 21b is lower than the melting point of the first material 11a, 21a. The melting point of the second material 11 b, 21 b is, for example, 54 to 58 ° C. When the melting point of the second material 11 b or 21 b is 54 ° C. or more, excessive fluidization of the second material 11 b or 21 b can be suppressed. Therefore, when the second materials 11 b and 21 b flow out to the vicinity of the surface of the NTC region 10 or the PTC region 20, it is possible to prevent the inhibition of the formation of the thermally conductive particles 12 and 22. The second materials 11b and 21b have appropriate fluidity when the melting point of the second materials 11b and 21b is 58 ° C. or less, and the heat conductive particles 12 and 22 in the second materials 11b and 21b (noncrystalline phase) It can encourage column formation.

(Thermoelectric conversion module)
As shown in FIG. 1, the thermoelectric conversion module 3 includes at least one electrode 31 (N-side electrode) disposed on the NTC region 10 and at least one electrode 32 (P Side electrode, at least one N-type thermoelectric element 34, and at least one P-type thermoelectric element 33. In the present embodiment, the thermoelectric conversion module 3 includes a plurality of the electrodes 31 and 32, the N-type thermoelectric element 34, and the P-type thermoelectric element 33, respectively.

  The N-type thermoelectric element 34 and the P-type thermoelectric element 33 are connected in series by the electrodes 31 and 32. An electrode 31 is disposed at one end of the N-type thermoelectric element 34, and an electrode 32 is disposed at the other end. An electrode 31 is disposed at one end of the P-type thermoelectric element 33, and an electrode 32 is disposed at the other end. The N-type thermoelectric element 34 and the P-type thermoelectric element 33 are arranged to cross the boundary between the NTC region 10 and the PTC region 20 in plan view.

  The thermoelectric conversion module 3 is configured to convert thermal energy into electrical energy by a temperature difference between the electrode 31 and the electrode 32. The material of the N-type thermoelectric element 34 and the P-type thermoelectric element 33 is not particularly limited. For example, a bismuth-tellurium-based material, a lead-tellurium-based material, a silicon-germanium-based material or the like can be used. In order to generate power more efficiently, it is preferable that the temperature difference between the electrodes 31 and 32 be as large as possible.

(Production method)
Next, an example of a method of manufacturing the above-described thermal rectifying substrate 2A will be described.
In the present embodiment, the NTC film F1 to be the NTC region 10 and the PTC film F2 to be the PTC region 20 are separately formed, and by combining these, the thermally rectifying substrate 2A is obtained (see FIG. 6). Therefore, first, a method of manufacturing the NTC film F1 and the PTC film F2 will be described.

  First, a coating C is formed on the surface of the magnetic particles M by, for example, a vapor phase deposition method such as CVD, a liquid phase growth method such as an alcohol liquid phase method, a liquid phase discharge method, or the like. Thereby, the heat conduction particles 12 and 22 as shown in FIG. 4 are obtained.

  Next, the N-side base material 11, the heat conductive particles 12, and the heat-shrinkable particles 13 are kneaded to obtain an N-side kneaded product 10A as shown in FIG. 5A (N-side kneading step). In the method of kneading in the N-side kneading step, for example, the respective materials are heated and mixed, and the N-side substrate 11 is formed into a sheet shape without being cured. When the N-side base material 11 includes the first material 11 a and the second material 11 b, these materials 11 a and 11 b are kneaded with the thermally conductive particles 12 and the thermally contracted particles 13. The same applies to the case where the N-side substrate 11 is made of three or more materials.

  Further, the P-side substrate 21 and the heat conductive particles 22 are kneaded to obtain a P-side kneaded product (P-side kneading step). In the method of kneading in the P-side kneading step, for example, the respective materials are mixed and molded into a sheet without being cured. When the P-side substrate 21 includes the first material 21 a and the second material 21 b, these materials 21 a and 21 b are kneaded with the heat conduction particles 22. The same applies to the case where the P-side substrate 21 is made of three or more materials.

At the time of the N-side kneading step, as shown in FIG. 5A, the heat conductive particles 12 and the heat-shrinkable particles 13 are uniformly dispersed in the N-side base material 11. Further, the N-side base material 11 is in a state where the first material 11a and the second material 11b are mixed.
At the time of the P-side kneading step, the heat conductive particles 22 are uniformly dispersed in the P-side base material 21. Although illustration is omitted, the P-side base material 21 is in a state where the first material 21a and the second material 21b are mixed, as in the N-side base material 11 in FIG. 5 (a).

Next, the sheet of the N-side kneaded material is compressed in the thickness direction to form a thin film, whereby the NTC film F1 is obtained (NTC film forming step).
Moreover, the PTC film F2 is obtained by compressing the sheet | seat of P side kneading | mixing material in the thickness direction, and making it thin-film-like (PTC film-forming process).

Next, the NTC film F1 and the PTC film F2 are heated to melt the N-side substrate 11 and the P-side substrate 21. In the N-side substrate 11 or the P-side substrate 21 fluidized by heating, the thermally conductive particles 12 and 22 and the thermally shrinkable particles 13 can move.
Here, the melting point of the first materials 11a and 21a is higher than the melting point of the second materials 11b and 21b. Therefore, in the process of curing the melted N-side base material 11 and P-side base material 21, the first materials 11a and 21a have lower fluidity than the second materials 11b and 21b, and are aggregated to form a crystalline phase. (See FIG. 5 (b)). At this time, in the second material 11b, 21b, the movement of the molecular chain is not constrained, and the heat conductive particles 12, 22 and the heat-shrinkable particle 13 are easily transferred to the second material 11b, 21b. On the other hand, in the first materials 11a and 21a, the attractive force acting between molecular chains is strong, and the thermally conductive particles 12 and 22 and the heat-shrinkable particles 13 hardly enter the first materials 11a and 21a. For this reason, the heat conductive particles 12 and 22 and the heat shrinkable particles 13 are stably present mainly in the second material 11 b and 21 b.

  Next, in a state in which the NTC film F1 is heated to the melting point or more of the N-side substrate 11, a magnetic field is applied to the NTC film F1. Further, in a state where the PTC film F2 is heated to the melting point or more of the P-side substrate 21, a magnetic field is applied to the PTC film F2 (magnetic alignment step). Here, when the N-side substrate 11 or the P-side substrate 21 is made of a plurality of types of materials, the melting point of the material having the highest melting point is referred to as “N-side substrate 11 and P-side substrate 21 Defined as the melting point of

  When a magnetic field is applied, for example, as shown in FIG. 5 (b), the S pole side of the magnet is brought close to one side of the sheet of the N-side kneader 10A (or P-side kneader) Close the N pole side. Since the thermally conductive particles 12 and 22 have magnetism, at least a portion of the thermally conductive particles 12 and 22 are arranged in a row in the thickness direction of the sheet by the magnetic field. In particular, the thermally conductive particles 12, 22 present in the low melting point and highly fluid second material 11b, 21b are easily aligned in the thickness direction. As a result, as shown in FIG. 5C, the heat conductive particles 12 are aligned in the thickness direction in the second material 11 b for the N-side kneaded material 10 A. Although illustration is omitted, the same applies to the P-side kneaded material.

Next, the NTC film F1 or the PTC film F2 is gradually cooled and cured.
In the NTC film F <b> 1, when the heat-shrinkable particles 13 expand at the time of slow cooling, the distance between the heat-conductive particles 12 around them expands (see FIG. 5 (d)).

Next, the shapes of the NTC film F1 and the PTC film F2 are arranged in a rectangular shape (rectangular shape) as shown in FIG. 6 (a).
Next, as shown in FIG. 6B, the NTC film F1 is cut to form a plurality of slits S1. Similarly, the PTC film F2 is cut to form a plurality of slits S2. The distance between the slits S1 of the NTC film F1 and the distance between the slits S2 of the PTC film F2 are preferably substantially equal.

  Next, the NTC film F1 and the PTC film F2 are combined by inserting the slit S1 into the slit S2. At this time, when viewed from the film thickness direction, the NTC film F1 and the PTC film F2 are alternately arranged. In this state, the NTC film F1 and the PTC film F2 are integrated by thermocompression bonding the NTC film F1 and the PTC film F2 (thermocompression bonding process). The thermocompression bonding is performed at a temperature higher than the melting points of the N-side substrate 11 and the P-side substrate 21. For example, when the first materials 11a and 21a of the N-side substrate 11 and the P-side substrate 21 are both polyethylene, thermocompression bonding is performed at the melting point of polyethylene or more (for example, 220 ° C., 4 Mpa). Thereby, PTC film F2 and NTC film F1 can be integrated more reliably, and heat conduction between PTC region 20 and NTC region 10 can be performed reliably.

Next, as shown in FIG. 6D, by cutting off both ends of the integrated NTC film F1 and PTC film F2, the heat rectifying substrate 2A is obtained.
Then, by providing the thermoelectric conversion module 3 on the upper surface 2a1 of the heat rectifying substrate 2A, the thermoelectric power generation device 1A can be manufactured.

  In addition, the order of each process in the said manufacturing method may be changed suitably. For example, the magnetic alignment process may be performed after the thermocompression bonding process. In this case, after the thermocompression bonding substrate 2A is obtained by thermocompression bonding, the S pole is brought closer to one of the upper surface 2a1 and the lower surface 2b1 of the heat rectifying substrate 2A, and the N pole is brought closer to the other. The thermally conductive particles 12, 22 in 10 and in the PTC region 20 can be aligned simultaneously.

(Action)
Next, the operation of the heat rectifying substrate 2A and the thermoelectric generator 1A configured as described above will be described.

FIG. 7A is a schematic view showing the state and thermal conductivity of the PTC region 20 (PTC film F2) according to the temperature change. The horizontal axis of the graph in FIG. 7A indicates the temperature, and the vertical axis indicates the thermal conductivity.
As shown in FIG. 7A, when the temperature is low, the heat conductive particles 22 included in the PTC region 20 are in contact with each other, and are connected in a row in the thickness direction of the PTC region 20. As a result, the heat is easily transmitted along the heat transfer particles 22. Hereinafter, the row in which the heat transfer particles 22 are connected is referred to as a P-side heat transfer path.

Further, as shown in FIG. 7A, when the temperature rises, the entire PTC region 20 thermally expands. Thereby, the heat conductive particles 22 included in the PTC region 20 are separated from each other, and the P-side heat conduction path is broken. Therefore, as the temperature rises, the thermal conductivity of the PTC region 20 decreases.
Thus, the thermal conductivity of the PTC region 20 increases at low temperatures and decreases at high temperatures. In other words, the thermal resistance of the PTC region 20 decreases at low temperatures and increases at high temperatures.

FIG. 7 (b) is a schematic view showing the state and thermal conductivity of the NTC region 10 according to the temperature change. The horizontal axis of the graph in FIG. 7 (b) indicates the temperature, and the vertical axis indicates the thermal conductivity.
As shown in FIG. 7B, when the temperature is high, the thermally conductive particles 12 included in the NTC region 10 are in contact with each other, and are connected in a row in the thickness direction of the NTC region 10. As a result, heat is easily transmitted along the heat conduction particles 12. Hereinafter, the row in which the heat transfer particles 12 are connected is referred to as an N-side heat transfer path.

As shown in FIG. 7 (b), the heat shrinkable particles 13 expand as the temperature decreases. Thereby, the heat conduction particles 12 present around the heat-shrinkable particles 13 are separated from each other, and the N-side heat conduction path is broken. Therefore, the thermal conductivity of the NTC region 10 decreases as the temperature decreases.
Thus, the thermal conductivity of the NTC region 10 increases at high temperatures and decreases at low temperatures. In other words, the thermal resistance of the NTC region 10 decreases at high temperatures and increases at low temperatures.

As shown in FIG. 7A, ideally, the state in which the heat conductive particles 22 are continuous and the state in which they are separated change in the PTC region 20 with a certain temperature (boundary temperature T) as a boundary. Therefore, when the temperature is lower than the boundary temperature T, the thermal conductivity increases (K _High ), and when the temperature is higher than the boundary temperature T, the thermal conductivity decreases (K _Low ).
As shown in FIG. 7B, ideally, the thermally conductive particles 12 are separated from each other in the NTC region 10 with the boundary temperature T as a boundary. Therefore, the thermal conductivity decreases (K _Low ) when the temperature is lower than the boundary temperature T, and the thermal conductivity increases when the temperature is higher than the boundary temperature T (K _High ).

  In FIGS. 7 (a) and 7 (b), although the thermal conductivity changes stepwise, in actuality, a portion of the row of heat conductive particles 12 and 22 that is separated from the ratio of the continuous portion The rate of change gradually with the temperature. Therefore, the thermal conductivity of the PTC region 20 gradually decreases as the temperature rises, and the thermal conductivity of the NTC region 10 gradually increases as the temperature rises.

  As mentioned above, PTC region 20 and NTC region 10 have opposite thermal properties. By superimposing such PTC region 20 and NTC region 10, it is possible to realize the thermal rectifying property of the thermal rectifying substrate 2A. Hereinafter, this will be described in more detail with reference to FIGS. 8 (a) and 8 (b).

  FIG. 8A is a schematic view in the case where the heat source H is in contact with the surface (N-side surface P1) on the NTC region 10 side of the thermal rectifying substrate 2A. FIG. 8B is a schematic view in the case where the heat source H is in contact with the surface (P-side surface P2) on the PTC region 20 side of the heat rectifying substrate 2A. The arrows shown in FIGS. 8A and 8B indicate the direction of heat flow. That is, heat moves from the N-side surface P1 to the P-side surface P2 in FIG. 8 (a), and moves from the P-side surface P2 to the N-side surface P1 in FIG. 8 (b). As described above, since the direction of the heat flow is reversed, the temperature gradient in the heat rectifying substrate 2A is also reversed in FIGS. 8 (a) and 8 (b).

9 (a) shows the thermal conductivity of the thermal rectifying substrate 2A corresponding to FIG. 8 (a), and FIG. 9 (b) shows the thermal conductivity of the thermal rectifying substrate 2A corresponding to FIG. 9 (b) It shows.
As shown in FIG. 9A, when the heat source H is brought into contact with the N-side surface P1, the temperature distribution in the heat rectifying substrate 2A decreases in temperature from the N-side surface P1 toward the P-side surface P2. It becomes such a gradient. Figure 9 (a) At represents the temperature distribution schematically represents the temperature of the N-side surface P1 and T _High, represents the temperature of the P-side surface P2 and T _Low.

Here, for example, in the thermal rectifying substrate 2A using the PTC region 20 and the NTC region 10 having ideal thermal characteristics as shown in FIGS. 7A and 7B, the PTC region 20 and the NTC region 10 are different. Consider the case where the temperature of the boundary surface becomes the boundary temperature T. At this time, the temperature of the NTC region 10 is higher than the boundary temperature T, and the temperature of the PTC region 20 is lower than the boundary temperature T. Therefore, both the NTC region 10 and the PTC region 20 are in the state of _high thermal conductivity (K _High ).

On the other hand, as shown in FIG. 9B, when the heat source H is brought into contact with the P-side surface P2, the temperature distribution in the heat rectifying substrate 2A is such that the temperature increases from the P-side surface P2 toward the N-side surface P1. It becomes a gradient that becomes smaller. Figure 9 (b) in represents the temperature distribution schematically represents the temperature of the P-side surface P2 and T _High, represents the temperature of the N-side surface P1 and T _Low.
Also in this case, in the same manner as the case of FIG. 9A, both the NTC region 10 and the PTC region 20 are in the state of _low thermal conductivity (K _Low ).

  Thus, in the thermal rectifying substrate 2A, the thermal conductivity from the NTC region 10 to the PTC region 20 is relatively large, and the thermal conductivity from the PTC region 20 to the NTC region 10 is relatively small. The thermal rectifying substrate 2A has the NTC regions 10 and the PTC regions 20 alternately arranged in both a plan view and a cross-sectional view. With this configuration, when heat is applied to the lower surface 2b1 of the heat rectifying substrate 2A, a temperature difference occurs in the surface of the upper surface 2a1. Specifically, the NTC region 10 in the upper surface 2a1 is lower in temperature than the PTC region 20 in the upper surface 2a1.

  As described above, according to the heat rectifying substrate 2A of the present embodiment, the heat-shrinkable particles 13 contained in the NTC region 10 shrink as the temperature rises. Therefore, the distance between the N-side heat conductive particles 12 around the heat-shrinkable particles 13 becomes smaller, and the thermal conductivity of the NTC region 10 becomes larger. On the other hand, in the PTC region 20, the P-side base material 21 expands as the temperature rises, and the distance between the P-side thermally conductive particles 22 increases. Therefore, the thermal conductivity of the PTC region 20 is reduced. By alternately arranging such PTC regions 20 and NTC regions 10 in plan view and cross sectional view, when one surface of the heat rectifying substrate 2A is heated, a temperature difference is generated in the other surface. Can.

Since the heat rectifying substrate 2A is mainly formed of the P-side base material 21 and the N-side base material 11 which are resins, it is relatively easy to manufacture and to have flexibility as a whole. it can. The flexibility of the heat rectifying substrate 2A makes it possible to attach it to a heat source of a complicated shape, and the heat rectifying substrate 2A can be applied to a wider range of applications.
Further, since it is not necessary to use a rare metal or the like as a raw material, the heat rectifying substrate 2A can be manufactured at relatively low cost.

Further, in plan view, the plurality of PTC regions 20 and the plurality of NTC regions 10 are formed in a strip shape long in the first direction X, and arranged alternately in the second direction Y.
With this configuration, for example, as shown in FIGS. 6A to 6D, the PTC film F2 to be the PTC region 20 and the NTC film F1 to be the NTC region 10 are separately formed, and each film is cut to cut each other. By combining them, the thermal rectifying substrate 2A can be manufactured relatively easily.

  Further, the heat rectifying substrate 2A is configured by combining the PTC film F2 and the NTC film F1. For this reason, it becomes possible to realize the thin-film thermal rectifying substrate 2A having a large surface area, and it becomes possible to apply the thermal rectifying substrate 2A to wider applications.

  Further, since the heat conductive particles 12 and 22 have magnetism, by applying a magnetic field when manufacturing the heat rectifying substrate 2A, the thickness of the heat conductive particles 12 and 22 is set to the heat rectifying substrate 2A. It can be arranged in the direction. Then, the thermal conduction particles 12, 22 are arranged in the thickness direction of the thermal rectifying substrate 2A, whereby the PTC characteristics in the thickness direction of the PTC region 20 and the NTC characteristics in the thickness direction of the NTC region 10 are stabilized. . Therefore, the thermal characteristics of the heat rectifying substrate 2A are stabilized.

  In addition, the N-side base material 11 includes a first material 11 a and a second material 11 b having a melting point lower than that of the first material 11 a. The first material 11a is a crystalline resin material, and the second material 11b is a noncrystalline resin material. Therefore, the mechanical strength of the NTC region 10 can be secured by the first material 11a which is a crystalline resin material. Then, when the NTC region 10 is heated and a magnetic field is applied, the particles 12 and 13 hardly enter the first material 11a which is a crystalline resin material, while the second material is a noncrystalline resin material. Particles 12 and 13 easily enter into 11b. Therefore, the thermally conductive particles 12 can be stably arranged in the film thickness direction in the second material 11 b. This effect is similarly obtained for the PTC region 20.

  Further, the thermoelectric power generation device 1A of the present embodiment includes the thermal rectifying substrate 2A and the thermoelectric conversion module 3. The thermoelectric conversion module 3 has a P-type thermoelectric element 33 and an N-type thermoelectric element 34 disposed so as to cross the boundary between the NTC region 10 and the PTC region 20 in plan view. With this configuration, the thermoelectric power generation device 1A can convert thermal energy into electrical energy by the temperature difference between the PTC region 20 and the NTC region 10.

Second Embodiment
Next, a second embodiment according to the present invention will be described, but the basic configuration is the same as the first embodiment. For this reason, the same code | symbol is attached | subjected to the same structure, the description is abbreviate | omitted, and only a different point is demonstrated.
In the present embodiment, the configuration of the heat rectifying substrate is different from that of the first embodiment.

FIG. 10 is a plan view of the thermoelectric power generation system 1B of the present embodiment. As shown in FIG. 10, the thermoelectric power generation device 1B includes a thermal rectifying substrate 2B and a thermoelectric conversion module 3.
The thermal rectifying substrate 2B has a plurality of NTC regions 10 and a plurality of PTC regions 20. In the present embodiment, the NTC regions 10 and the PTC regions 20 are alternately arranged in both the first direction X and the second direction Y in plan view shown in FIG.
Although illustration is omitted, the cross-sectional shape of the heat rectifying substrate 2B of the present embodiment is the same as the cross-sectional shape of the first embodiment shown in FIG. That is, in the cross-sectional view, the thermal rectifying substrate 2B has the NTC regions 10 and the PTC regions 20 alternately arranged. The heat rectifying substrate 2B has an upper layer portion and a lower layer portion, the PTC region 20 is disposed below the NTC region 10 included in the upper layer portion, and the NTC region 20 is included below the upper layer portion. Region 10 is arranged.

11 (a) to 11 (c) are diagrams showing an example of a method of manufacturing the heat rectifying substrate 2B in the present embodiment. The steps for obtaining the NTC film F1 and the PTC film F2 are the same as in the first embodiment, and thus the description thereof is omitted.
In the present embodiment, as shown in FIGS. 11A and 11B, a plurality of strip-like NTC films F1 and PTC films F2 are prepared. Each film F1 and F2 may be formed in a band shape from the beginning. Alternatively, the films F1 and F2 formed in a rectangular shape may be cut into strips.

Next, as shown in FIG. 11 (c), a plurality of band-like films F1 and F2 are knitted. By thermally compressing and integrating the films F1 and F2 in this state, the heat rectifying substrate 2B is obtained. As in the first embodiment, the order of the steps may be interchanged.
Then, by providing the thermoelectric conversion module 3 on the heat rectifying substrate 2B, the thermoelectric power generation device 1B can be manufactured.
Also in the case of the present embodiment, the same effects as those of the first embodiment can be obtained.

  Hereinafter, the above embodiment will be described using specific examples. The present invention is not limited to the following examples.

In this embodiment, when the NTC regions 10 and the PTC regions 20 are alternately arranged in a cross sectional view as shown in FIG. 12 and the heater H is provided on one surface, the temperature difference in the surface opposite to the heater H It was confirmed.
As the first materials 11a and 21a, crystalline polyethylene (crystalline HDPE sheet manufactured by AS ONE Corporation: model number 6-619-01, Vicat softening temperature based on JIS K 6760: 124 ° C.) was used. Non-crystalline polyethylene (manufactured by Sumitomo Chemical Co., Ltd., EXCELLE (registered trademark), model number: VL-100, Vicat softening temperature based on JIS K 6760: 70 ° C.) was used as the second materials 11 b and 21 b. A powder of spiked Ni particles (manufactured by New Metals End Chemicals Corporation, particle size 1 to 2 μm) was used as the heat conductive particles 12 and 22. A powder of manganese nitride of composition Mn-Sn-Zn-N (Smartec (registered trademark) series, Smartec-H, manufactured by High Purity Chemical Laboratory, Inc.) as heat-shrinkable particles 13 is crushed with a mortar and then sieved. The particle size is then reduced to 20 μm or less.

  The crystalline polyethylene (the first materials 11a and 21a) and the non-crystalline polyethylene (the second materials 11b and 21b) were kneaded in the same volume for both the N-side substrate 11 and the P-side substrate 21. The N-side substrate 11 was melt-kneaded with the powder of the N-side thermally conductive particles 12 and the heat-shrinkable particles 13, and the P-side substrate 21 was melt-kneaded with the powder of the P-side thermally conductive particles 22. The NTC film F1 has a volume density of the N-side thermally conductive particles 12 (Ni) of 5 vol. %, And the volume density of the heat shrinkable particles 13 is 5 vol. %. The PTC film F2 has a volume density of the P-side thermally conductive particles 22 (Ni) of 5 Vol. %.

  Each was melt-kneaded and then thinned using a hot press to obtain an NTC film F1 and a PTC film F2. The thickness of each of the NTC film F1 and the PTC film F2 was set to 150 μm by using a spacer during hot pressing. The thermocompression bonding of the NTC film F1 and the PTC film F2 at a temperature (220 ° C.) higher than the melting temperature of the first material 11a, 21a (crystalline polyethylene), and then the first material 11a, 21a (crystalline polyethylene) Magnetic alignment was performed by applying a magnetic force of 0.2 T uniformly (at an adsorption force of 14.7 N) uniformly in the film while heating at a temperature (220 ° C.) higher than the melting temperature. Slow cooling was performed by natural air cooling until the temperature of the NTC film F1 and the PTC film F2 reached room temperature. Thus, a thin-film thermal rectifying substrate (FIG. 12) having a thickness of about 300 μm was obtained.

As shown in FIG. 12, a heater H was provided on one side of the heat rectifying substrate. Hereinafter, the surface of the PTC region 20 in the surface opposite to the heater H is referred to as a P-side surface P3 and the surface of the NTC region 10 is referred to as an N-side surface P4.
The results of changing the temperature of the heater H while measuring the temperature by providing thermocouples on the P-side surface P3 and the N-side surface P4 respectively are shown in FIG.

The data of “NTC → PTC (P3)” in FIG. 13 indicates the temperature measurement result of the P-side surface P3. Moreover, the data of "PTC-> NTC (P4)" have shown the temperature measurement result of the N side surface P4.
As shown in FIG. 13, the temperature of the P-side surface P3 is higher than that of the N-side surface P4. This is because the thermal resistance when heat is transferred from the NTC region 10 toward the PTC region 20 is smaller than the thermal resistance when heat is transferred from the PTC region 20 toward the NTC region 10.
As described above, according to the heat rectifying substrate of the present embodiment, a temperature difference can be generated in the surface opposite to the heater H.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, in the first and second embodiments, the N-side substrate 11 and the P-side substrate 21 are respectively formed of two types of materials, but the configuration of the substrates 11 and 21 can be changed as appropriate. For example, the N-side substrate 11 and the P-side substrate 21 may be configured by one type of resin material. Even in this case, the heat conductive particles 12 and 22 can be aligned in the film thickness direction by heating the N-side substrate 11 and the P-side substrate 21 and applying a magnetic field in a flowable state.

  Further, in the first and second embodiments, the thermally conductive particles 12 and 22 are aligned in the film thickness direction, but even if such alignment is not performed, the thermally conductive particles 12 and 22 are mutually It is possible to realize NTC characteristics or PTC characteristics to some extent by changing the interval of. Therefore, the magnetic alignment step of the embodiment is not essential.

  In addition, it is possible to replace components in the above-described embodiment with known components as appropriate without departing from the spirit of the present invention, and the above-described embodiments and modifications may be combined as appropriate.

  DESCRIPTION OF SYMBOLS 1A, 1B ... Thermoelectric-generation apparatus 2A, 2B ... Thermal rectification board | substrate 3 ... Thermoelectric conversion module 10 ... NTC area | region 11 ... N side base material 12 ... N side heat conduction particle 13 ... heat contraction particle 20 ... PTC area 21 ... P side Base material 22 ... P side heat conduction particle 31, 32 ... electrode 33 ... P type thermoelectric element 34 ... N type thermoelectric element X ... first direction Y ... second direction Z ... thickness direction

Claims (4)

With multiple PTC areas and multiple NTC areas,
In plan view and cross-sectional view, the plurality of PTC regions and the plurality of NTC regions are alternately arranged,
The plurality of PTC regions include a P-side base formed of a resin, and a plurality of P-side thermally conductive particles disposed in the P-side base,
The plurality of NTC regions include an N-side substrate formed of a resin, a plurality of N-side thermally conductive particles and a plurality of heat-shrinkable particles disposed in the N-side substrate,
The plurality of P-side thermally conductive particles have a thermal conductivity larger than that of the P-side base material,
The plurality of N-side thermally conductive particles have a thermal conductivity larger than that of the N-side substrate,
The heat rectifying substrate, wherein the plurality of heat shrinkable particles shrink with an increase in temperature.   In a plan view, the plurality of PTC regions and the plurality of NTC regions are formed in a strip shape elongated in a first direction, and are alternately arranged in a second direction orthogonal to the first direction. The thermal rectifying substrate according to 1.   The thermal system according to claim 1, wherein the plurality of PTC regions and the plurality of NTC regions are alternately arranged in both a first direction and a second direction orthogonal to the first direction in a plan view. Rectifying board. A thermal rectifying substrate according to any one of claims 1 to 3;
A thermoelectric conversion module provided on the thermal rectifying substrate,
The thermoelectric conversion module includes at least one P-type thermoelectric element, at least one N-type thermoelectric element, and a plurality of electrodes.
The P-type thermoelectric element and the N-type thermoelectric element are connected by the electrodes, and the electrodes are provided at both ends of the P-type thermoelectric element and the N-type thermoelectric element, respectively.
The thermoelectric generation device according to claim 1, wherein the P-type thermoelectric element and the N-type thermoelectric element are arranged to straddle the boundary between the PTC region and the NTC region in plan view.

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