JP2009016812A - Thermoelectric conversion module and power generator using the same - Google Patents

Abstract

A thermoelectric conversion module capable of realizing a large temperature difference in an element and increasing the amount of power generation, and a power generation apparatus using the same.
A thermoelectric conversion unit in which a single or a plurality of thermoelectric conversion units connected to a p-type thermoelectric conversion element and an n-type thermoelectric conversion element are arranged two-dimensionally or a substrate on both surfaces of the thermoelectric conversion unit is provided. Each of the substrates 20 and 30 is a module and is embedded in a low heat conductive portion 21 and 31 covering the surface of the thermoelectric conversion unit 10 and a hole provided in the low heat conductive portion, and one end side thereof is p-type and n-type thermoelectric The other end side is connected to the connection part of the conversion element and is composed of the high heat conduction portions 22 and 32 exposed from the holes on the surface of the low heat conduction portion, and each high heat conduction portion surface exposed from the low heat conduction portion is a temperature contact portion with high heat conduction. It is characterized by being connected to 40 and 50, respectively.
[Selection] Figure 3

Description

  The present invention relates to a thermoelectric conversion module that converts heat into electricity using a temperature difference and a power generation device in which the thermoelectric conversion module is connected to a solar cell.

  As global warming has progressed and problems such as bad weather and rising seawater have become seriously serious, solar cells are not only important in Japan as an energy source that does not emit carbon dioxide, a greenhouse gas, It is also recognized in Europe and the United States, and its introduction into homes and offices has become popular. Seventy percent of the solar cells introduced are Si-based solar cells, most of which are crystalline (single crystal or polycrystalline).

In midsummer daytime, the solar energy falling on the earth is about 1000 W / m ² , and the average power generation amount under the optimum conditions of these solar cells is about 150 W / m ² . That is, the conversion efficiency is about 15%. However, in reality, it depends strongly on the latitude of the place where you live, the orientation of the house, the presence of obstacles, the difference in season, the weather, and the like, and the value of 15% is realized throughout the year. is not.

The average amount of power required in an average home will be about 4 kW, but if the average home wants to introduce solar cells, about 26 m ² will be required. Considering effective efficiency, about 40 m ² will be necessary. Securing such a roof area is not so easy. Therefore, in order to make the area as small as possible, a solar cell unit having a high conversion efficiency is required.

  Further, during the daytime of midsummer, the solar cell temperature is 80 ° C. or higher in the time zone where the amount of power generation is the largest for the solar cell. When the temperature of a crystalline silicon solar cell rises to 80 ° C., the conversion efficiency at room temperature falls by 20 to 30% (see FIG. 1). In order to compensate for the decrease in efficiency, the area of the solar cell placed on the roof has to be increased, which is not only expensive, but it is also difficult to secure the area on the roof. If the effective efficiency of the solar cell can be increased, the required solar cell area on the roof can be reduced, leading to cost reduction. For these reasons, an inexpensive solar cell with high power generation efficiency is desired.

  In the past, there was an idea to generate electricity by applying the thermoelectric conversion element on the back surface, taking advantage of the fact that the solar cell itself would be close to 80 ° C around noon in midsummer weather (see Patent Documents 1 and 2). It has not been realized as a business. This is because, in order to generate as much power as possible, the conventional thermoelectric conversion element has a structure in which the space between the high temperature side and the low temperature side is as adiabatic as possible. Therefore, if the conventional thermoelectric conversion element is temporarily bonded to the solar cell, the temperature of the solar cell further increases, resulting in a decrease in the amount of power generated from the solar cell itself. The fact that it was thought that there was no point in assisting had a great influence.

  Furthermore, since it is difficult to produce a conventional thermoelectric conversion element, only an element with a small area can be produced. For this reason, the complexity of the process of adhering the element to the back of a large solar cell is also cited.

  There is also a situation that the thermoelectric conversion element is too expensive. This is a structure of a conventional thermoelectric conversion element using the Seebeck effect, and a structure in which a p-type and an n-type element are coupled in a “π” shape to stand vertically to a lower substrate. It is necessary to connect n-type-p-type in series, and the thermoelectric material generally used is Bi-Te, which is a brittle material and difficult to join with solder. For this reason, the reason is that it can only be made by hand.

  For this reason, it is not practical to use it on the back surface of a solar cell substrate, which is indispensable for a low price, and has not actually appeared in the market as a product.

  Under such a technical background, Patent Literature 3 and Non-Patent Literature 1 propose thermoelectric conversion elements that can generate power efficiently. That is, this thermoelectric conversion element is formed such that a thin film p-type thermoelectric conversion element made of a p-type material and a thin film n-type thermoelectric conversion element made of an n-type material are connected in series, and are formed on both sides thereof. A thermoelectric conversion unit is formed by forming electrodes, and a flexible film-like substrate composed of two types of materials having different thermal conductivities is provided on both sides of the thermoelectric conversion unit. On the unit side, a film is provided with a material such as polyimide resin, which is an insulator with low thermal conductivity, and on the side opposite to the joining surface of the thermoelectric conversion unit, a metal material such as copper with high thermal conductivity is in the form of the film. It is provided so that it may be located in a part of outer surface of a board | substrate.

  By adopting such a configuration, a temperature difference is generated inside the film substrate from the difference in heat flux of each layer when a temperature difference is applied to the upper and lower surfaces of the film substrate, and the thickness direction of the film substrate The temperature gradient is efficiently converted into a temperature gradient in the in-plane direction of the film-like substrate, and the temperature gradient is used to efficiently generate power with the thermoelectric conversion unit. The inventions described in Patent Document 3 and Non-Patent Document 1 have high mechanical strength, excellent workability, are easy to automate, can be mass-produced, and are flexible to curved surfaces. The object of the present invention is to provide a thermoelectric conversion element with high power generation efficiency that can be installed and is not limited in installation location.

  Specifically, using a mask, a p-type and n-type thermoelectric material is formed on the resin sheet by sputtering while controlling the element structure to form a thermoelectric conversion element portion, and the thermoelectric conversion element The thermoelectric conversion element is sandwiched by attaching another resin sheet on the part. Next, on both outer side surfaces of the bonded resin sheet and in a portion corresponding to the joint portion of the p-type and n-type thermoelectric conversion elements, a metal having good thermal conductivity such as copper is used to have the same size as the joint portion. Form an isomorphic pattern.

  Actually, using a polyimide sheet (shown as material-A in FIG. 2) coated or affixed with copper (shown as material-B in FIG. 2) on one side, a thermoelectric conversion element (see FIG. 2) on the back side. The other side of the polyimide sheet with no copper attached is bonded onto the thermoelectric conversion element, and the copper thin films on both surfaces of the bonded sheet are etched. To cut the desired pattern. A cross section of this structure is shown in FIG. This copper part comes into contact with the high temperature part and the low temperature part. Due to the heat conduction from there, there was a temperature difference in the thermoelectric conversion element parallel to the resin sheet surface, and power was generated.

However, in this method, the heat conduction from the temperature contact portion on the high temperature side and the low temperature side (hereinafter referred to as the temperature contact portion) is only the heat conduction by thermal diffusion in the resin, and therefore the heat conductivity to the thermoelectric conversion element. However, since the temperature gradient is low and the temperature gradient in the thermoelectric conversion element is difficult to be attached, the problem is that the amount of power generation becomes small.
JP 2001-53322 A JP 2003-69070 A JP 2006-186255 A NEDO 2006 Research Grants Project Results Report Industrial Technology Research Grants Project “Energy / Environmental Technology” Project ID: 03B70010c = Presentation of “Research and development of sheet-like flexible thermoelectric conversion elements for low-temperature waste heat utilization”

  The present invention has been a problem in the thermoelectric conversion elements proposed in Patent Document 3 and Non-Patent Document 1, and the heat conduction from the temperature contact portion on the high temperature side and the low temperature side is only the heat conduction by heat diffusion in the resin. It is an object of the present invention to improve the problems of low heat conductivity to the thermoelectric conversion element due to the fact that the power generation amount is low and a small amount of power generation due to the difficulty of attaching a temperature gradient in the thermoelectric conversion element.

  Therefore, a thermoelectric conversion unit in which a p-type thermoelectric conversion element and an n-type thermoelectric conversion element are connected is two-dimensionally arranged in a single or plural number, and electrodes are formed on both sides thereof to form a single thermoelectric conversion unit or an assembly thereof. In addition, the present inventors diligently studied the thermoelectric conversion module provided with the substrate made of a material having different thermal conductivity on both surfaces of the thermoelectric conversion unit alone or an assembly thereof. The material with high thermal conductivity of the substrate on one surface side of the p-type thermoelectric conversion element penetrates or substantially penetrates the material with low thermal conductivity and is connected to or close to the connection part or the vicinity part of the p-type thermoelectric conversion element. The material with high thermal conductivity of the substrate on the surface side of the n-type thermoelectric conversion element passes through or substantially penetrates the material with low thermal conductivity. Is connected to or adjacent to a nearby part and each surface side of the material having high thermal conductivity is connected to a temperature contact portion made of a material having high thermal conductivity, thereby providing a high temperature part and a low temperature part. As a result, it has been found that a large temperature difference is realized in the thermoelectric conversion module. The present invention has been completed by such technical discovery.

That is, the invention according to claim 1
A thin-film p-type thermoelectric conversion element made of a p-type material and a thin-film n-type thermoelectric conversion element made of an n-type material are connected directly or via a metal material, two-dimensionally arranging one or more thermoelectric conversion units. A thermoelectric conversion unit is formed by arranging substrates made of materials having different thermal conductivities on both sides of a single thermoelectric conversion unit or an assembly thereof, and arranging one substrate side on the high temperature side and the other substrate side on the low temperature side. Assuming modules,
Each of the substrates is made of a material having a low thermal conductivity and has a low thermal conductivity part covering the surface of the thermoelectric conversion unit alone or an assembly thereof, and a thickness of the low thermal conductivity part made of a material having a high thermal conductivity. Embedded in a through-hole or recess provided along the direction, and one end thereof is connected to or close to the connection portion of the p-type thermoelectric conversion element or n-type thermoelectric conversion element or its vicinity, and the other end is the surface of the low heat conduction portion A temperature contact portion composed of a material having a high thermal conductivity and a surface of the high thermal conductivity portion exposed from the through hole or the concave portion of the surface of the low thermal conductivity portion. It is connected.

Next, the invention according to claim 2
Based on the thermoelectric conversion module according to the invention of claim 1,
The material with high thermal conductivity is metal,
The invention according to claim 3
On the premise of the thermoelectric conversion module according to the invention of claim 1 or 2,
A plurality of the thermoelectric conversion units or their aggregates are stacked via an electrical insulating layer, and the substrate is provided on the outer surface of a pair of thermoelectric conversion units or their aggregates located on the outermost side. As a feature,
The invention according to claim 4
The temperature contact portion to which the surface of the high thermal conductivity portion of one substrate is connected is disposed on the high temperature side or the low temperature side, and the temperature contact portion on the other substrate is disposed in a state of being in thermal contact with the atmosphere side. On the premise of the thermoelectric conversion module according to the invention described in any one of 3,
The thermal conductivity (κc) and the cross-sectional area (Sc) of the high thermal conductivity portion in the substrate, and the thermal conductivity (κa) and the cross-sectional area (Sa) of the low thermal conductivity portion in the substrate are:
1.2κa × Sa ≧ κc × Sc (Formula 1)
And having a relationship
0.8κa × Sa ≦ κc × Sc (Formula 2)
It has the relationship of these.

The invention according to claim 5
Based on the thermoelectric conversion module according to any one of claims 1 to 3,
The surface of the temperature contact portion is covered with a substantially black oxide film or a material having high thermal conductivity,
The invention according to claim 6
Based on the thermoelectric conversion module according to any one of claims 1 to 3,
The surface of the temperature contact portion of the substrate disposed on the low temperature side is roughened,
The invention according to claim 7 provides:
Based on the thermoelectric conversion module according to any one of claims 1 to 3,
A heat sink is added to the surface of the temperature contact portion of the substrate disposed on the low temperature side,
The invention according to claim 8 provides:
Assuming the thermoelectric conversion module according to any one of claims 1 to 7,
The material having low thermal conductivity in the substrate is resin or glass, and the thickness of the substrate from the surface of the thermoelectric conversion unit alone or its aggregate is 75 μm or more.

Next, the invention according to claim 9 is:
Assuming a power generator,
The thermoelectric conversion module according to any one of claims 1 to 8 is adhered to the back side of the solar cell, and the power is generated by a temperature difference between the solar cell and the outside air,
The invention according to claim 10 is:
On the premise of the power generation device according to the invention of claim 9,
When the thermal conductivity of the adhesive used for bonding the solar cell and the thermoelectric conversion module is (W / mK) and the thickness of the adhesive is (d), the ratio of (W / mK) / (d) is 1000 or more. It is characterized by
The invention according to claim 11 is:
On the premise of the power generation device according to the invention of claim 9,
The substrate surface on the surface side not contacting the solar cell in the thermoelectric conversion module is covered with each temperature contact portion connected to the high heat conduction portion exposed from the through hole or the concave portion of the surface of the low heat conduction portion. age,
The invention according to claim 12
On the premise of the power generation device according to the invention of claim 9,
The solar cell is an amorphous Si solar cell,
The invention according to claim 13 is
On the premise of the power generation device according to the invention of claim 9,
When the temperature on the surface side in contact with the solar cell in the thermoelectric conversion module is lower than the temperature on the surface side not in contact with the solar cell, a switch that switches between positive and negative of electricity is provided in the circuit of the thermoelectric conversion module It is characterized by being.

According to the thermoelectric conversion module according to the present invention,
A thin-film p-type thermoelectric conversion element made of a p-type material and a thin-film n-type thermoelectric conversion element made of an n-type material are connected directly or via a metal material, two-dimensionally arranging one or more thermoelectric conversion units. A thermoelectric conversion unit is formed by arranging substrates made of materials having different thermal conductivities on both sides of a single thermoelectric conversion unit or an assembly thereof, and arranging one substrate side on the high temperature side and the other substrate side on the low temperature side. In the module
Each of the substrates is made of a material having a low thermal conductivity and has a low thermal conductivity part covering the surface of the thermoelectric conversion unit alone or an assembly thereof, and a thickness of the low thermal conductivity part made of a material having a high thermal conductivity. Embedded in a through-hole or recess provided along the direction, and one end thereof is connected to or close to the connection portion of the p-type thermoelectric conversion element or n-type thermoelectric conversion element or its vicinity, and the other end is the surface of the low heat conduction portion A temperature contact portion composed of a material having a high thermal conductivity and a surface of the high thermal conductivity portion exposed from the through hole or the concave portion of the surface of the low thermal conductivity portion. It has a connected structure.

  For this reason, the temperature of the high temperature part and the low temperature part can be efficiently transmitted to the thermoelectric conversion unit (thermoelectric element part) through each temperature contact part and each substrate, thereby realizing a large temperature difference in the thermoelectric conversion module. As a result, the amount of power generation can be increased and improved.

  Moreover, by adhering the thermoelectric conversion module according to the present invention to the back surface side of the solar cell, the power generation efficiency in the solar cell can be assisted, and the effective power generation efficiency of the solar cell can be increased.

  Hereinafter, embodiments of the present invention will be described in detail.

  First, a thermoelectric conversion module according to the present invention includes a thermoelectric conversion unit in which a thin film p-type thermoelectric conversion element made of a p-type material and a thin film n-type thermoelectric conversion element made of an n-type material are connected as shown in FIG. 10 are provided with thin-film substrates 20 and 30 made of materials having different thermal conductivities on one side, and one substrate side is disposed on the high temperature side and the other substrate side is disposed on the low temperature side. Each of the substrates 20 and 30 is made of a material having a low heat conductivity and covers the surface of the thermoelectric conversion unit 10, and is made of a material having a high heat conductivity and the low heat conductivity. It is buried in a through hole or a recess provided along the thickness direction of the conductive portions 21 and 31, and one end side thereof is connected to the connection portion of the p-type thermoelectric conversion element or the n-type thermoelectric conversion element or a vicinity thereof. Or the other end side is composed of the high heat conduction portions 22 and 32 exposed from the through holes or the recesses on the surface of the low heat conduction portions 21 and 31, and is exposed from the through holes or the recesses on the surfaces of the low heat conduction portions 21 and 31. The surface of the high heat conduction parts 22 and 32 is connected to temperature contact parts 40 and 50 made of a material having high heat conductivity.

  And when the board | substrate side shown with the code | symbol 20 of the thermoelectric conversion module which concerns on this invention is each arrange | positioned to the high temperature side, and the board | substrate side shown with the code | symbol 30 is each low temperature side, the heat | fever (temperature) in the high temperature temperature contact part 40 is high heat conduction. It is transmitted to the p-type thermoelectric conversion element or the n-type thermoelectric conversion element (thermoelectric element part) via the part 22, and the heat (temperature) from the p-type thermoelectric conversion element or the n-type thermoelectric conversion element (thermoelectric element part) is also highly thermally conductive. Since the heat is efficiently transmitted to the low temperature contact part 50 via the part 32, a large temperature difference can be realized in the thermoelectric conversion module.

1. Configuration of Thermoelectric Conversion Module (a) Thermoelectric Conversion Material As a thermoelectric conversion material, FeSi ₂ which has low thermoelectric properties but is abundant in resources other than chalcogen compounds such as IrSb ₃ , Bi ₂ Te ₃ and PbTe having high performance. And silicides such as SiGe. In addition, by adjusting the amount of various additive elements such as P, B, and Al alone or combined so that the carrier concentration in the Si semiconductor is about 10 ²⁴ (1 / m ³ ) and the amount added, the Seebeck coefficient can be increased. Si-based thermoelectric conversion materials that are extremely large and have significantly improved thermoelectric conversion efficiency can also be used. In addition, any known material can be used. In Si, at least one of Ge, C, and Sn is 5 to 10 atomic%, and at least one of additive elements for making Si a p-type semiconductor or an n-type semiconductor is 0.001 atomic% to 20 atomic%. Si-based thermoelectric conversion materials such as Si-based thermoelectric conversion materials containing a crystal structure in which one or more of Ge, C, and Sn or further one or more of additional elements are precipitated are included in the grain boundary portion of polycrystalline Si. This is preferable because the conversion efficiency is remarkably high.
(B) Material with high thermal conductivity It is preferable that the material with high thermal conductivity that constitutes the high thermal conductivity part and the temperature contact part of the substrate is a metal or the like, specifically, copper, aluminum, or other thermal conductivity. Examples include high-grade metals, alloys, and ceramics. Moreover, about the high heat conductive part of the board | substrate arrange | positioned at a low temperature side and the board | substrate arrange | positioned at a high temperature side, both may be comprised with the same material, and may be comprised using a different material, and are arbitrary.
(C) Temperature contact part It is preferable that the surface of the said temperature contact part is coat | covered with the substantially black oxide film or the material with high heat conductivity. Examples of the above materials include copper oxides and resin materials with high thermal conductivity and high environmental resistance. This makes it easy to follow the temperature of the high temperature part and the low temperature part, and the temperature inside the thermoelectric conversion module. This is preferable because the gradient becomes large and large power generation is possible.

  Moreover, in the thermoelectric conversion module of this invention, it is preferable to roughen the surface of the said temperature contact part (low temperature side temperature contact part) of the board | substrate arrange | positioned at a low temperature side. In order to roughen the surface of the low temperature side temperature contact portion, it is only necessary to damage the surface by sandblasting or file. For the surface roughness, the effective surface area is twice or more than the apparent area. The effect is great if it becomes rough so that the heat transfer coefficient becomes twice or more.

Moreover, in the thermoelectric conversion module of this invention, it is also possible to take the structure which added the heat sink to the surface of the low temperature side temperature contact part. By adopting such a configuration, it is possible to make the effective surface area more than twice the apparent surface area (simply seen from the dimensions), and obtain a large heat transfer coefficient (20 W / m ² K or more). Therefore, a large temperature difference between the high temperature part and the low temperature part is obtained, and the power generation amount is increased.

FIG. 4 is a graph showing a result of simulating the resin thickness dependence of the total power generation amount in a solar cell having a thermoelectric conversion module bonded to the back surface side. That is, when a thermoelectric conversion module to which a polyimide resin having a thermal conductivity of 0.2 W / mK is applied as a low thermal conductivity material constituting the low thermal conductivity portion is bonded to the back surface of the solar cell, the back surface temperature of the solar cell is set to 80. The graph shows the relationship between the resin thickness (μm) of the polyimide resin constituting the low heat conduction part and the total power generation amount in the solar cell when the atmospheric temperature is 30 ° C. The resin thickness is a distance from the surface of the thermoelectric conversion unit alone or its aggregate to the surface of the low thermal conductivity portion (substrate).
(D) Low thermal conductivity material Examples of the low thermal conductivity material constituting the low thermal conductivity portion of the substrate include resins such as polyimide and foamed polystyrene, or glass. When the thickness of the thermoelectric conversion unit alone or collectively honor its substrate until the surface is 75μm or more, it can be seen that power generation amount as shown in FIG. 4 is preferable because a realistic 30 W / m ² or more. If the thickness of the substrate from the single thermoelectric conversion unit or the aggregate surface to the surface thereof is less than 75 μm, the actual desired value for supporting the power generation amount of the solar cell may be reduced. As an auxiliary to the solar cell, a power generation amount of 30 W / m ² or more is desired (corresponding to 3% in terms of power generation efficiency), and 75 μm or more is preferable to ensure this. It should be noted that the low thermal conductivity portions of the substrate disposed on the low temperature side and the substrate disposed on the high temperature side may both be composed of the same material or may be composed of different materials.

  Further, the material constituting the low thermal conductivity portion is an electrically insulating material, and is preferably a material having as low a thermal conductivity as possible. Depending on the purpose, a resin material such as polyimide and foamed polystyrene, or a glass material can be used properly. The low thermal conductivity part is desirably low in thermal conductivity, and the low thermal conductivity part is desirably thick because the temperature difference between thermoelectric conversion elements becomes large.

  And when the conventional three-dimensional thermoelectric conversion element with high heat insulation is bonded to the back side of the solar cell, there is a risk that the temperature of the solar cell rises as described above, but the low heat conduction part by the resin of about 100 μm The thermal insulation is not a problem. In addition, when the low heat conduction part becomes too thick, the temperature rise of the solar cell itself may become a problem. However, when the low heat conduction part is several mm, the influence of the temperature rise is not so great.

2. Manufacture of Thermoelectric Conversion Module As described above, the thermoelectric conversion module according to the present invention includes a single two-dimensional thermoelectric conversion unit in which a p-type thermoelectric conversion element and an n-type thermoelectric conversion element are connected directly or via a metal material. Each of the thermoelectric conversion units arranged in a plurality or both of the aggregates has a structure in which substrates each composed of a low thermal conductivity portion and a high thermal conductivity portion are provided.

  For example, a p-type mask as shown in FIG. 5A is fixed to one surface of a 500 μm-thick polyimide resin sheet constituting the low thermal conductivity portion, and placed in a sputtering apparatus in this state. As shown in FIG. 5B, for example, a p-type material is formed to a thickness of about 1 μm.

  After that, an n-type mask as shown in FIG. 6A is fixed, an n-type material is formed so as to have the same film thickness as the p-type material, and the thin film p-type thermoelectric conversion element 11 and the thin film n-type are formed. A thermoelectric conversion unit aggregate (see FIG. 7A) in which a plurality of thermoelectric conversion units 10 shown in FIG. 7B connected to the thermoelectric conversion elements 12 are two-dimensionally arranged is obtained.

  Further, as shown in FIG. 7 (A), electrodes 13 and 14 are attached to each row in which a plurality of thermoelectric conversion units 10 are arranged in series, and the film thickness of about 500 μm constituting the other low heat conduction portion is formed thereon. A polyimide resin sheet is bonded to sandwich the thermoelectric conversion unit assembly.

  Next, as shown in FIG. 8 (B), aiming at the connection part (1.4 mm × 2.8 mm) of the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 or its vicinity part 15, Excimer laser is irradiated from the corresponding side for 12.5 seconds through a mask with a hole with a diameter of 0.5 mm, and a through-hole is opened to a position where the connection part or its vicinity can be seen with a diameter of about 0.5 mm. Then, an adhesive having good thermal conductivity is added to the through hole, and as shown in FIG. 8A, for example, a copper material 60 (high thermal conductivity) having a diameter of 0.5 mm × 0.5 mm and having a long thermal conductivity is used. Embedded in the part 22).

  Similarly, an excimer laser is irradiated for 12.5 seconds through a mask having a hole with a diameter of 0.5 mm to a connection portion corresponding to the low temperature side (surface opposite to the high temperature side) or its vicinity, and the diameter is 0.5 mm. The through-hole is opened to the position where the connection site or its vicinity can be seen. In addition, if it is irradiated for a long time of 12.5 seconds or longer, there is a possibility that the thermoelectric element part is also penetrated. However, when it is stopped in 12.5 seconds, it is confirmed that the thermoelectric element part is almost left. . Thereafter, an adhesive having thermal conductivity is applied to the surface of the copper material 60 having a diameter of 0.5 mm, and is embedded in the through hole to form a high thermal conductivity portion. In addition, when the high heat conduction part is constituted by embedding the copper material 60, the high heat conduction part may not be electrically connected to the thermoelectric element part, but there is no problem as long as the thermal contact is obtained. Therefore, the through-hole in which the copper material is embedded may be constituted by a recess in which the thermoelectric element portion side is closed and the opposite surface side is opened, and one end side of the high heat conduction portion made of copper material or the like is p-type thermoelectric. What is necessary is just to be connected to or close to the connection part of the conversion element or the n-type thermoelectric conversion element (thermoelectric element part) or its vicinity 15. In FIG. 8C, one end side of the high heat conduction portions 22 and 32 having a rectangular cross section is connected to the connection portion of the p-type thermoelectric conversion element 11 or the n-type thermoelectric conversion element (thermoelectric element portion) 12 or a vicinity portion 15 thereof. It is a conceptual diagram which shows the state connected or adjoined.

  Further, through a mask on which a film can be formed at a position corresponding to the position of the thermoelectric conversion unit 10 of the low heat conduction portion 21 on the substrate, as shown in FIG. 9, the temperature contact portion on the high temperature side (for example, using Cu, 9 is formed by sputtering, and the low-temperature conductive portion 31 on the opposite side is also provided with a low-temperature-side temperature contact portion (sometimes referred to as a thin film for heat dissipation). A module is obtained.

  It should be noted that the contact size of the high thermal conductive portions 22 and 32 that are in thermal contact with the connection portion of the p-type thermoelectric conversion element 11 or the n-type thermoelectric conversion element 12 in the thermoelectric conversion unit 10 or the vicinity thereof 15, The cross-sectional sizes of the temperature contact portion 40 and the temperature contact portion 50 on the low temperature side do not necessarily need to match. In particular, the cross-sectional size of the low temperature side temperature contact portion 50 (for example, the area of the temperature contact portion with the atmosphere) should be spread almost over the entire thermoelectric conversion unit 10. This is because the power generation in the thermoelectric conversion element is larger when the heat radiation on the low temperature side is sufficiently performed. The graph of FIG. 11 shows the result of simulating the relationship with the heat dissipation. Here, the heat dissipation coefficient is an amount corresponding to a product of (area of the low temperature portion) × (roughness) × (thermal conductivity) of the temperature contact portion arranged on the low temperature side. Therefore, a larger area is better. However, if the temperature contact part spreads to the adjacent thermoelectric conversion unit, it will come into electrical contact, so each thermoelectric conversion unit is covered with a metal with good thermal conductivity for heat dissipation, etc. It is better to connect them. Moreover, it is better to make the surface of the temperature contact portion on the low temperature side uneven so that heat can be radiated as easily as possible. In order to increase the surface area, a three-dimensional structure and heat radiation fins are more likely to have a temperature difference, and the amount of power generation is large and effective.

  Further, in the thermoelectric conversion module according to the present invention, a single thermoelectric conversion unit or an assembly thereof in which a thermoelectric conversion unit composed of a p-type thermoelectric conversion element 11 and an n-type thermoelectric conversion element 12 is arranged one-dimensionally or plurally. As shown in FIG. 17, a structure in which a plurality of layers are stacked with an electrical insulating layer 70 interposed therebetween may be used.

3. Optimum conditions of “cross-sectional area of high heat conduction part” and “cross-sectional area of low heat conduction part” in the substrate The temperature contact part 80 to which the surface of the high heat conduction part 81 in one substrate is connected is arranged on the high temperature side or the low temperature side, In the thermoelectric conversion module according to the present invention in which the temperature contact portion 80 in the substrate is disposed in a state of being in thermal contact with the atmosphere side,
The heat flow condition that maximizes the power generation is
The thermal conductivity (κc) and the cross-sectional area (Sc) of the high thermal conductivity portion 81 in the substrate, and the thermal conductivity (κa) and the cross-sectional area (Sa) of the low thermal conductivity portion 82 in the substrate are:
1.2κa × Sa ≧ κc × Sc (Formula 1)
And having a relationship
0.8κa × Sa ≦ κc × Sc (Formula 2)
It is a case where it has the relationship of.

  Hereinafter, description will be made assuming that the heat flow in the thermoelectric conversion module (however, for the sake of simplicity, the thermoelectric conversion unit alone is assumed instead of the thermoelectric conversion unit aggregate) is the heat flow shown in FIG.

  Here, the meaning of each symbol is as follows.

S0: Cross-sectional area of substrate per thermoelectric conversion unit (thermoelectric element 83) = Sa + Sc
Sc: Cross-sectional area of high heat conduction part in substrate per thermoelectric conversion unit (thermoelectric element) Sa: Cross-sectional area of low heat conduction part in substrate per thermoelectric conversion unit (thermoelectric element) St: Thermoelectric conversion unit (thermoelectric element) ) Cross section per unit d: Thickness of “low thermal conduction part” L: Length of thermoelectric conversion unit (thermoelectric element) κc: Thermal conductivity of high thermal conduction part κa: Thermal conductivity of low thermal conduction material κt: Thermoelectric Thermal conductivity of conversion unit (thermoelectric element) α: Heat dissipation coefficient from T5 (atmosphere) Pf: Power factor of thermoelectric conversion unit (thermoelectric element) = S _B ² / (ρ _n + ρ _p )
ρ _n + ρ _p : Electric conductivity of n-type material and p-type material S _B : Seebeck coefficient Q 0: Energy irradiated from sunlight per thermoelectric conversion unit (thermoelectric element) (1000 W at 1 m ² ),
This is also
Q0 = α · S0 · (T5−T4): Equal to the energy released from the low temperature side surface.

  Here, the following relational expression is established between the heat flow (Q) shown in FIG. 12 and the above definition.

Q1 = κc × Sc × (T1-T2) × 2 / d
Q2 = κa × Sa × (T1−T4) / d
Q3 = κa × Sc × (T1−T3) × 2 / d
Q4 = κa × Sc × (T2−T4) × 2 / d
Q5 = κc × Sc × (T3−T4) × 2 / d
Q6 = κt × St × (T2−T3) / L
Further, the following relational expression is established between the heat flows from the relationship of continuous heat flow.

Q0 = Q1 + Q2 + Q3
Q1 = Q4 + Q6
Q5 = Q3 + Q6
When these three formulas obtained from the relationship of continuity of heat flow and the above four formulas of Q0 = α · S0 · (T5−T4) are combined, each temperature T1, T2, T3, T4, which are four variables, is automatically set. Can be obtained. However, T5 is an atmospheric temperature, for example, a fixed value such as 30 ° C.

  If the temperature difference (T2−T3) obtained from these relational expressions is used, the power generation amount of the thermoelectric conversion unit (thermoelectric element) can be obtained.

That is, the power generation amount Pw per thermoelectric conversion unit (thermoelectric element) is
Pw = Pf × (T2−T3) ² × St / L
What is necessary is just to obtain | require the conditions which become the maximum of.

  Qualitatively, in order to increase the temperature difference ΔT = | T2−T3 | that determines the amount of power generation, it is necessary to increase the temperature difference between the temperatures T1 and T4.

  For this purpose, it is important to reduce the thermal conductivity of the low thermal conductivity material part as much as possible, thicken the low thermal conductivity material part, and increase the thermal conductivity of the high thermal conductivity part thermally connected to the high temperature part and the low temperature part. is there.

  If the high heat conduction part is made thick, the temperature difference between T1 and T4 becomes small, and eventually the temperature difference between T2 and T3 becomes small. Further, when the cross-sectional area of the high heat conducting portion is reduced, the temperature difference between T1 and T4 increases, but the temperature difference between T2 and T3 decreases.

  For this reason, it turns out that the appropriate value which maximizes the electric power generation amount of a thermoelectric conversion module exists.

  As a result, it can be seen that the power generation amount Pw has the maximum value in the vicinity where the value of “κa × Sa” is substantially equal to the value of “κc × Sc”.

When the condition is obtained by setting a range where 80% or more of the maximum power generation amount is secured as a preferable range of power generation amount
1.2κa × Sa ≧ κc × Sc (Formula 1)
When,
0.8κa × Sa ≦ κc × Sc (Formula 2)
Is required to be within a preferred range.

4). Power Generation Device The power generation device according to the present invention is characterized in that the thermoelectric conversion module is bonded to the back side of the solar cell and generates power with a temperature difference between the solar cell and the outside air temperature.

  With such a configuration, it is possible to generate power using the temperature difference between the back surface of the solar cell and the outside air temperature, thereby improving the decrease in power generation efficiency due to the temperature increase of the solar cell.

By the way, in the power generation device according to the present invention, the thermal conductivity of the adhesive used for bonding the solar cell and the thermoelectric conversion module and the thickness of the adhesive are related to the power generation efficiency, and the thermal conductivity of the adhesive is (W / mK), where the thickness of the adhesive is (d), the ratio of (W / mK) / (d) is preferably 1000 or more. The heat flowing through the resin, which is a low thermoelectric material of about 0.1 (W / mK), is about 0.1 / 10 ⁻³ = 100 when the thickness is about 1 mm. Since it should not become a thermal resistance at the bonding portion with the solar cell, the heat flow in the bonding portion is 10 times or more compared to the heat flow of the resin, that is, the ratio of (W / mK) / (d) is 1000 or more. Is desirable.

  Moreover, about the board | substrate surface of each thermoelectric conversion unit of the surface side which is not in contact with the solar cell in a thermoelectric conversion module, by each temperature contact part connected to the high heat conduction part exposed from the through-hole or recessed part of the surface of a low heat conduction part It is preferably coated.

  Here, the kind of solar cell to which the thermoelectric conversion module according to the present invention is bonded is not particularly limited, and examples thereof include amorphous Si solar cells. Amorphous Si solar cells have a larger solar absorption coefficient than crystalline Si solar cells, so the film thickness of Si is 1 μm or less. In addition, since amorphous Si can be formed on a resin, a flexible solar cell can be made. However, since the power generation efficiency is low, about 8% on average, the type mounted on the roof requires a large area to achieve 4 kW, and the range of use is limited even at a low price. However, unlike crystalline Si solar cells, amorphous Si solar cells have a feature that power generation efficiency does not decrease even when the temperature rises. Therefore, the type in which the thermoelectric conversion module according to the present invention sandwiched between substrates made of thick resin or the like is bonded to the back surface of the solar cell can realize more efficient power generation. Since any type of solar cell can be powered by the thermoelectric conversion module according to the present invention independently of the solar cell itself, the thermoelectric conversion module according to the present invention can be applied to any type of solar cell. Can be used.

  Next, in the power generation device according to the present invention, when the temperature on the surface side in contact with the solar cell in the thermoelectric conversion module becomes lower than the temperature on the surface side not in contact with the solar cell, the positive / negative of electricity is determined. It is preferable that the switch to switch is provided in the circuit of the thermoelectric conversion module. The reason for providing the switch is that the temperature on the surface side in contact with the solar cell is not necessarily a high temperature part, and depending on the outside air temperature or the way of installing the solar cell, it becomes a low temperature part and may generate a reverse voltage. Because there is. In this case, if the structure is switched between positive and negative with a switch, power generation is possible even at night without the sun. Therefore, it is preferable to provide a switch in the circuit that can automatically switch between positive and negative. In the present specification, unless otherwise specified, the bonding portion side with the back surface of the solar cell is described as a high temperature portion.

  Examples of the present invention will be specifically described below, but the present invention is not limited to the following examples.

  A p-type mask as shown in FIG. 5 (A) is fixed to one surface of a polyimide resin sheet having a thickness of 500 μm, and placed in a sputtering apparatus in this state, and p-type material iron is 1 μm thick. The film was formed in the pattern shape shown in FIG.

  Next, an n-type mask as shown in FIG. 6A is fixed, and Ni as an n-type material is formed in a pattern shape shown in FIG. 6B so as to have the same film thickness as the p-type material. The thermoelectric conversion units 10 in which the thin film p-type thermoelectric conversion elements 11 made of iron and the thin film n-type thermoelectric conversion elements 12 made of Ni are directly connected are two-dimensionally arranged in seven horizontal rows and eight vertical rows. A thermoelectric conversion unit assembly (see FIG. 7A) was obtained.

  Furthermore, as shown in FIG. 7 (A), electrodes 13 and 14 are attached to each row in which thermoelectric conversion units 10 are arranged in series in 7 horizontal rows, and a total of 100 thermoelectric conversion units in 3 cm × 3 cm. After the (thermoelectric element) was formed, a polyimide resin sheet having a thickness of about 500 μm was adhered thereon to sandwich the thermoelectric conversion unit assembly.

  Next, as shown in FIG. 8B, the diameter from the side corresponding to the high temperature side is aimed at the connection part (1.4 mm × 2.8 mm) of the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12. An excimer laser is applied through a mask with a hole of 0.5 mm, and a through hole is drilled to the point where the connection site can be seen with a diameter of about 0.5 mm. Adhesive with good thermal conductivity (XILENCE) As shown in FIG. 8A, a copper material 60 having a diameter of 0.5 mm × 0.5 mm and having a high thermal conductivity (constituting the high thermal conductivity portion 22) was embedded.

  Similarly, an excimer laser is applied to the connection site corresponding to the low temperature side (the surface opposite to the high temperature side) through a mask having a hole with a diameter of 0.5 mm, and the through hole reaches a position where the connection site can be seen with a diameter of 0.5 mm. Opened.

  The excimer laser irradiation conditions are as follows.

Excimer laser: Exitech excimer laser processing machine PS2000
Wavelength used: 248 (nm)
Optical system used: 10x lens Transmission frequency = 100 Hz
It was expanded to about 1 cm × 5 cm so that the energy density = 2 J / cm ² .

Hole diameter: 0.5mm diameter
Moreover, when the depth of the through-hole per 1 irradiation (100 Hz) to a polyimide resin sheet was measured on the said conditions, it is 0.4 micrometer, and in the case of a 500 micrometer-thick polyimide resin sheet, 1250 times of irradiation is enough. Therefore, it was decided to irradiate once for 12.5 seconds.

  Thereafter, as shown in FIG. 8 (A), an adhesive (silver tim manufactured by XILENCE) is applied to the surface of the copper material 60 having a diameter of 0.5 mm × 0.5 mm and embedded in the through hole. A high heat conduction part was obtained. In addition, in the operation | work which embeds the copper material 60 and forms a highly heat-conductive part, since the confirmation of the said connection part is hard to understand exactly | strictly, the connection part and the high heat-conduction part should just be substantially contact (thermal contact). .

  Further, through a mask capable of forming a film at a position corresponding to the position of the thermoelectric conversion unit 10 of the low heat conducting portion 21, as shown in FIG. 9, the temperature contact portion on the high temperature side (Cu is used and the film thickness is about 10 μm. Thickness 40 was formed by sputtering, and a low-temperature-side temperature contact portion (thin film for heat dissipation) was also formed on the opposite low-temperature conductive portion 31 to obtain a thermoelectric conversion module shown in FIG.

  And one surface of the obtained thermoelectric conversion module was used for the back side of a commercially available solar cell (Daiwa solar cell L type: single crystal Si used. 110 mm × 60 mm) with the above adhesive (silver tim manufactured by XILENCE). And glued.

  Around noon during summer sunny weather, the solar cell was pointed in the direction of the sun, and after about 1 hour, the temperature in the vicinity of the thermoelectric conversion module on the back of the solar cell was measured to show 83 ° C, and the outside temperature was 28 ° C. there were. And since the surface of a thermoelectric conversion module is 68 degreeC, it can be judged that the temperature difference of the high temperature side and low temperature side of a thermoelectric conversion module is 15 degreeC (= 83 degreeC-68 degreeC).

At this time, the power generation amount of the solar cell was 1.4 V × 420 mA = 0.59 W. When this is converted into the conversion efficiency at 1 m ² , it is 8.9%. On the other hand, the power from the thermoelectric conversion module was 45 mV × 3 mA = 135 μW.

This time, the power was low because it was tried with a material with high thermal conductivity of Fe-Ni system. However, assuming that the Bi-Te system is used under the same conditions, the power is 20 W / m ² , which is effective for solar cells. In terms of conversion efficiency, it becomes 2%. Therefore, it is confirmed that the efficiency of the solar cell can be covered at a considerable rate.

  A thermoelectric conversion module was produced in substantially the same manner as in Example 1. In addition, by changing the mask used in Example 1, the arrangement of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is such that the high-temperature parts and the low-temperature parts are adjacent to each other as shown in FIG. did. With this structure arrangement, the contrast between the high temperature part and the low temperature part is easier to make.

  This thermoelectric conversion module is adhered to the back side of an amorphous silicon resin solar cell (SANYO AT-7665: 56 mm × 58 mm) using the above-mentioned adhesive (silver tim manufactured by XILENCE), and the same as in Example 1. The measurement was performed under the following conditions.

  The temperature of the resin-made solar cell was about 80 ° C. Although the temperature of the thermoelectric conversion module could not be measured, the amount of power generated from the thermoelectric conversion module was 150 μW. Since the amorphous silicon resin solar cell itself is translucent, it seems that the temperature difference is more likely than in Example 1.

At this time, the amount of power generated from the solar cell itself was 4 V × 10 mA = 4 × 10 ⁻² W.

When this is converted into the amount of power generated at 1 m ² , it is 12.3 W / m ² (conversion efficiency is about 1.23%). Suppose used Bi-Te-based as the material of the thermoelectric conversion element, Seebeck coefficient, the power generation amount and calculated using the thermal conductivity and the like 20W / m ^2, and the larger amount of power generation than the amorphous Si resin solar cell It is confirmed that

  As shown in FIG. 13 (B), the copper foil 90 of the polyimide sheet 91 (thickness 38 μm) having a copper foil 90 (film thickness 8 μm) on one side is etched as shown in FIG. A band-shaped thermal electrode 92 was formed on the substrate. These formation portions of the thermal electrodes 92 are provided so as to correspond to the positions of the low temperature portion and the high temperature portion of the thermoelectric conversion unit (thermoelectric element) described below. As shown in FIG. 13B, three belt-like thermal electrodes 92 are provided on one side of the polyimide sheet 91 shown on the upper side, and two pieces are provided on one side of the polyimide sheet 91 shown on the lower side. Each of the strip-shaped thermal electrodes 92 is provided, and when the surfaces of the two polyimide sheets 91 to which the copper foil 90 is not attached are overlapped, the strip-shaped thermal electrodes 92 do not overlap each other. Each thermal electrode 92 is provided so as to have a positional relationship.

  Next, as shown in FIG. 13C, BiTe and SbTe are formed on the other surface (the surface on which the copper foil 90 is not attached) of the polyimide sheet 91 provided with the two strip-shaped thermal electrodes 92. The p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 are formed by sputtering, and a plurality of U-shapes connected by an electrode (metal material) 93 on one end side of these elements are used. A thermoelectric conversion unit (thermoelectric element), that is, a thermoelectric conversion unit assembly was produced.

  In addition, the size of a pair of thermoelectric elements (thermoelectric conversion units) composed of the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 is 5 mm × 5 mm, and a plurality of thermoelectric elements are arranged effectively. The size of the part is 5 cm × 5 cm. Accordingly, 10 pairs × 10 pairs = 100 thermoelectric elements are formed on the surface of the polyimide sheet 91.

  Next, a thermoelectric conversion unit assembly is formed on the surface of the polyimide sheet 91 on which the thermoelectric conversion unit assembly is formed (that is, a polyimide sheet provided with two strip-shaped thermal electrodes 92). FIG. 13D shows the planar side of the other polyimide sheet 91 in which the body is not formed (that is, the polyimide sheet in which the three strip-shaped thermal electrodes 92 are provided and the thermoelectric conversion unit assembly is not formed). Thus, the thermoelectric conversion unit assembly was sandwiched between a pair of polyimide sheets 91 by overlapping and bonding with an adhesive.

  In addition, the p-type thermoelectric conversion element 11, the n-type thermoelectric conversion element 12, the electrode (metal material) 93, and the belt-shaped thermoelectrode 92 having a structure in which the thermoelectric conversion unit aggregate is sandwiched between a pair of polyimide sheets 91. The positional relationship is as shown in FIG.

  Next, with respect to the structure in which the thermoelectric conversion unit aggregate is sandwiched between a pair of polyimide sheets 91, a pair of polystyrene foam plates 97 and 97 are polymerized from above and below as shown in FIG. An embodiment having a structure shown in FIG. 15B, sandwiched between a pair of thermally conductive copper plates 95 (thickness 0.5 mm) in which brass bars 94 are soldered to the outer surface of the expanded polystyrene plates 97, 97. A thermoelectric conversion module according to Example 3 was produced. The brass bar 94 penetrates the expanded polystyrene plate 97, and the tip thereof is arranged so as to be in thermal contact with each position of the thermal electrode 92.

  And about the thermoelectric conversion module which concerns on Example 3, one copper plate 95 side was closely_contact | adhered thermally to the 80 degreeC hotplate, and the other surface side was made to thermally radiate freely at about 30 degreeC air | atmosphere. Then, the temperature of the central portion of the hot electrode 92 disposed on the low temperature side and the temperature of the copper plate 95 in contact with the atmosphere were measured.

  Further, a brass rod 94 (brass) whose diameter size (refer to the “radius of brass rod” column in Table 1) is changed with respect to an effective area of 5 mm × 50 mm in one row of thermoelectric elements (corresponding to 10 pairs of thermoelectric conversion units). 2 bars (2 per each hot electrode island) are soldered to the copper plate 95, and the brass bar 94 is disposed so as to be in thermal contact with each hot electrode to generate the power. The amount was measured. The results are shown in Table 1. In addition, the thermal conductivity of the polystyrene foam is (0.07 W / mK).

発電量が最大値となる条件は、表１の「(κc×Ｓc)／(κa×Ｓa)」欄の結果から、
１．２κa×Ｓa ≧ κc×Ｓc（式１）、かつ、０．８κa×Ｓa ≦ κc×Ｓc（式２）の関係を満たしている中で成立していることが確認された。

The conditions for the maximum power generation amount are as follows from the results in the “(κc × Sc) / (κa × Sa)” column of Table 1.
It was confirmed that the relationship was satisfied while satisfying the relationship of 1.2κa × Sa ≧ κc × Sc (formula 1) and 0.8κa × Sa ≦ κc × sc (formula 2).

  Similar to Example 3, a unit assembly of the first layer was prepared in which a band-shaped thermal electrode made of copper foil was provided on one surface and a thermoelectric conversion unit assembly was provided on the opposite surface side. At this time, unlike Example 3, 10 pairs × 10 pairs = 100 thermoelectric conversion units so that the thicknesses of the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 on the polyimide sheet 91 are about 1 nm. Was formed (see FIG. 17).

  Next, on the unit assembly of the first layer, a silica layer having a thickness of 10 nm is formed as the electrical insulating layer 70, and on the silica layer, the second layer is assembled in the same manner as the unit assembly of the first layer. A unit assembly was prepared, and further, a third layer unit assembly was prepared (see FIG. 17), and a silica layer was formed on the uppermost layer in the same manner as above until the 100th unit assembly was overlaid.

  Next, on the uppermost silica layer, a belt-like thermal electrode made of copper foil is provided on one surface, and a polyimide sheet is adhered to produce a unit assembly laminate 100, and 16 and FIG. 18, a pair of foamed polystyrene plates 97, 97 are polymerized, and a brass rod 94 is soldered to one surface with respect to the outer surfaces of the foamed polystyrene plates 97, 97. A thermoelectric conversion module according to Example 4 was produced by being sandwiched between copper plates 95.

  The brass rod 94 is disposed so as to penetrate the foamed polystyrene plate 97 and the tip thereof is in thermal contact with each position of the thermal electrode.

  And about the thermoelectric conversion module which concerns on Example 4, it is the same as that of Example 3 in the state which made the one copper plate side thermally_contact | adhered thermally to a hotplate, and the other surface side was freely radiated about 25 degreeC air | atmosphere. The power generation amount was measured. The results are shown in Table 2.

実施例４の積層型の場合、実施例３の１層型より少し出力が大きかった理由は、薄膜型にして二次元性が出たためと思われる。

In the case of the laminated type of Example 4, the reason why the output was slightly larger than that of the single layer type of Example 3 seems to be that the two-dimensionality was obtained by using the thin film type.

  According to the thermoelectric conversion module according to the present invention, since a large temperature difference is realized in the thermoelectric conversion module, it is possible to increase and improve the amount of power generation. Also, the thermoelectric conversion module according to the present invention is connected to the back surface of the solar cell. By adhering to the side, the effective power generation efficiency of the solar cell can be increased. Therefore, the thermoelectric conversion module according to the present invention has industrial applicability to be used by being incorporated in a solar cell.

The graph which shows the temperature characteristic of the conventional crystalline Si type solar cell. Sectional drawing which shows the principal part structure of the thermoelectric conversion element which concerns on a prior art. The schematic perspective view of the thermoelectric conversion module which concerns on this invention. The graph which shows the result of having simulated the resin thickness dependence of the total electric power generation amount of the solar cell by which the thermoelectric conversion module was adhere | attached on the back side. FIG. 5A is a plan view showing an example of a p-type material mask used in manufacturing the thermoelectric conversion module according to the present invention, and FIG. 5B is formed using the p-type material mask. The schematic perspective view which shows the pattern of a p-type thermoelectric conversion element. 6A is a plan view showing an example of an n-type material mask used when manufacturing the thermoelectric conversion module according to the present invention, and FIG. 6B is formed using the n-type material mask. The schematic perspective view which shows the pattern of an n-type thermoelectric conversion element. FIG. 7A is a plan view of a thermoelectric conversion unit assembly in which a plurality of thermoelectric conversion units in which p-type thermoelectric conversion elements and n-type thermoelectric conversion elements are connected are two-dimensionally arranged, and FIG. The schematic perspective view which shows the pattern of the thermoelectric conversion unit in which the p-type thermoelectric conversion element and the n-type thermoelectric conversion element were directly connected. FIG. 8A is an explanatory view showing a state in which the copper material constituting the high thermal conductivity portion is embedded in the through hole of the thermoelectric conversion module according to the present invention, and FIG. 8B is a p-type thermoelectric conversion in which the through hole is provided. FIG. 8C is an explanatory view showing the connection part of the element or the n-type thermoelectric conversion element or its vicinity, and FIG. 8C shows the connection part of the p-type thermoelectric conversion element or the n-type thermoelectric conversion element or the one end side of the high thermal conductivity portion having a rectangular cross section The conceptual diagram which shows the state connected or adjoined to the vicinity site | part. The top view of the thermoelectric conversion module which concerns on this invention. The top view of the thermoelectric conversion module which concerns on the modification with which the p-type thermoelectric conversion element and the n-type thermoelectric conversion element were connected. The graph which shows the result of having simulated the relationship between the thermal radiation coefficient in the low temperature side temperature contact part of the thermoelectric conversion module which concerns on this invention, and total electric power generation amount. The schematic of the heat flow in the thermoelectric conversion module which concerns on this invention. FIG. 13A to FIG. 13D are explanatory diagrams illustrating manufacturing steps of the thermoelectric conversion module according to the third embodiment. The top view in the middle of manufacture of the thermoelectric conversion module which concerns on Example 3. FIG. FIG. 15A to FIG. 15B are also explanatory diagrams illustrating manufacturing steps of the thermoelectric conversion module according to the third embodiment. FIG. 10 is an exploded perspective view illustrating a configuration of a thermoelectric conversion module according to a fourth embodiment. FIG. 9 is a perspective view illustrating a partial configuration of a thermoelectric conversion module according to a fourth embodiment. FIG. 6 is a schematic cross-sectional view of a thermoelectric conversion module according to a fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thermoelectric conversion unit 11 p-type thermoelectric conversion element 12 n-type thermoelectric conversion element 13 Electrode 14 Electrode 20 Substrate 21 Low thermal conduction part 22 High thermal conduction part 30 Substrate 31 Low thermal conduction part 32 High thermal conduction part 40 Temperature contact part 50 Temperature contact part 60 Copper Material 70 Electrical insulation layer 80 Temperature contact part 81 High heat conduction part 82 Low heat conduction part 83 Thermoelectric conversion unit (thermoelectric element)
90 Copper foil 91 Polyimide sheet 92 Thermal electrode 93 Electrode (metal material)
94 Brass rod 95 Copper plate 97 Styrofoam plate 100 Laminate part

Claims (13)

A thin-film p-type thermoelectric conversion element made of a p-type material and a thin-film n-type thermoelectric conversion element made of an n-type material are connected directly or via a metal material, two-dimensionally arranging one or more thermoelectric conversion units. A thermoelectric conversion unit is formed by arranging substrates made of materials having different thermal conductivities on both sides of a single thermoelectric conversion unit or an assembly thereof, and arranging one substrate side on the high temperature side and the other substrate side on the low temperature side. In the module
Each of the substrates is made of a material having a low thermal conductivity and has a low thermal conductivity part covering the surface of the thermoelectric conversion unit alone or an assembly thereof, and a thickness of the low thermal conductivity part made of a material having a high thermal conductivity. Embedded in a through-hole or recess provided along the direction, and one end thereof is connected to or close to the connection portion of the p-type thermoelectric conversion element or n-type thermoelectric conversion element or its vicinity, and the other end is the surface of the low heat conduction portion A temperature contact portion composed of a material having a high thermal conductivity and a surface of the high thermal conductivity portion exposed from the through hole or the concave portion of the surface of the low thermal conductivity portion. A thermoelectric conversion module characterized by being connected.   The thermoelectric conversion module according to claim 1, wherein the material having a high thermal conductivity is a metal.   A plurality of the thermoelectric conversion units or their aggregates are stacked via an electrical insulating layer, and the substrate is provided on the outer surface of a pair of thermoelectric conversion units or their aggregates located on the outermost side. The thermoelectric conversion module according to claim 1 or 2, characterized by the above. In the thermoelectric conversion module in which the temperature contact portion to which the surface of the high thermal conductivity portion of one substrate is connected is disposed on the high temperature side or the low temperature side, and the temperature contact portion on the other substrate is disposed in thermal contact with the atmosphere side. ,
The thermal conductivity (κc) and the cross-sectional area (Sc) of the high thermal conductivity portion in the substrate, and the thermal conductivity (κa) and the cross-sectional area (Sa) of the low thermal conductivity portion in the substrate are:
1.2κa × Sa ≧ κc × Sc (Formula 1)
And having a relationship
0.8κa × Sa ≦ κc × Sc (Formula 2)
The thermoelectric conversion module according to claim 1, wherein the thermoelectric conversion module has the following relationship.   The thermoelectric conversion module according to claim 1, wherein the surface of the temperature contact portion is covered with a substantially black oxide film or a material having high thermal conductivity.   The surface of the said temperature contact part of the board | substrate arrange | positioned at a low temperature side is roughened, The thermoelectric conversion module in any one of Claims 1-3 characterized by the above-mentioned.   The thermoelectric conversion module according to claim 1, wherein a heat radiating plate is added to a surface of the temperature contact portion of the substrate disposed on the low temperature side.   The material having low thermal conductivity in the substrate is resin or glass, and the thickness of the thermoelectric conversion unit of the substrate or its aggregate surface to the surface is 75 μm or more. The thermoelectric conversion module according to any one of the above.   A thermoelectric conversion module according to any one of claims 1 to 8 is adhered to a back surface side of a solar cell, and a power generation device is configured to generate power with a temperature difference between the solar cell and outside air.   When the thermal conductivity of the adhesive used for bonding the solar cell and the thermoelectric conversion module is (W / mK) and the thickness of the adhesive is (d), the ratio of (W / mK) / (d) is 1000 or more. The power generator according to claim 9, wherein the power generator is provided.   The substrate surface on the surface side not contacting the solar cell in the thermoelectric conversion module is covered with each temperature contact portion connected to the high heat conduction portion exposed from the through hole or the concave portion of the surface of the low heat conduction portion. The power generator according to claim 9.   The said solar cell is an amorphous Si solar cell, The electric power generating apparatus of Claim 9 characterized by the above-mentioned.   When the temperature on the surface side in contact with the solar cell in the thermoelectric conversion module is lower than the temperature on the surface side not in contact with the solar cell, a switch that switches between positive and negative of electricity is provided in the circuit of the thermoelectric conversion module The power generator according to claim 9, wherein the power generator is provided.

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