Substrates for thermoelectric power generation devices and thermoelectric power generation devices
A flexible substrate with deformable beams and legs in a thermoelectric power generation device addresses the efficiency and manufacturing complexity issues of three-dimensional devices, enhancing power output and mounting flexibility.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- WASEDA UNIV
- Filing Date
- 2024-10-30
- Publication Date
- 2026-05-15
AI Technical Summary
Existing thermoelectric power generation devices face challenges in achieving high power generation efficiency in three-dimensional configurations due to limited distance from the heat source surface to the heat dissipation surface, and the process of creating such devices is complex.
A flexible substrate with a sheet-like insulating base material and a metal layer, featuring a cell substrate portion with strip-shaped beams and legs that deform to form a three-dimensional structure, increasing contact area with the heat source and allowing multiple cell substrates to be made three-dimensional simultaneously.
The solution enhances power generation efficiency by increasing the contact area with the heat source and allowing easy manufacturing in three dimensions, resulting in improved power output and flexibility in mounting on various surfaces.
Smart Images
Figure 2026079446000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a substrate for a thermoelectric power generation device and a thermoelectric power generation device.
Background Art
[0002] A paper-cut thermoelectric power generation device (Thermoelectric generator, (TEG)) that forms cuts in a sheet-like wiring board and transforms it into a three-dimensional structure is known. The inventors have proposed a paper-cut thermoelectric power generation device in which a pair of L-shaped cuts symmetric about two axes are formed in a rectangular wiring board to form a pair of leg portions and a beam portion (see Patent Document 1). In the thermoelectric power generation device of Patent Document 1, by moving the tips of a pair of leg portions that contact the heat source surface closer to each other, the pair of leg portions rise obliquely upward from the heat source surface, and the beam portion floats from the heat source surface to form a three-dimensional structure in a floating posture. In this thermoelectric power generation device, thermoelectric elements that generate electricity due to a temperature difference are respectively attached to the pair of leg portions. Since the beam portion serving as the heat dissipation surface can be sufficiently separated from the heat source surface, high power generation efficiency can be obtained.
[0003] In addition, a paper-cut thermoelectric power generation device is known in which a plurality of cuts are arranged in a zigzag pattern on a rectangular wiring board, and the wiring board is stretched so that each cut becomes a substantially rhombic opening, thereby transforming it into a mesh-like three-dimensional structure (see Non-Patent Document 1).
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Non-Patent Documents
[0005]
Non-Patent Document 1
[0006] Incidentally, since the voltage generated from a pair of thermoelectric elements is small, it is common to construct a thermoelectric power generation device by arranging many thermoelectric elements in an array. In the thermoelectric power generation device of Patent Document 1, many thermoelectric elements are arranged in an array by making multiple units consisting of one beam and a pair of legs as described above in a continuous sequence. However, with such a structure, when it comes to creating a three-dimensional thermoelectric power generation device, each unit must be deformed, which makes the process complicated. On the other hand, in the thermoelectric power generation device of Non-Patent Document 1, it is easy to create a three-dimensional device by simply stretching the entire wiring board, but it has the problem of low power generation efficiency. This is because, when the thermoelectric power generation device is created in three dimensions, the distance from the heat source surface to the heat dissipation surface cannot be large, and the contact part with the heat source surface and the part furthest from the heat source surface are linear.
[0007] This invention has been made in view of the above circumstances, and aims to provide a substrate for a thermoelectric power generation device and a thermoelectric power generation device that can improve power generation efficiency and are easy to manufacture in three dimensions. [Means for solving the problem]
[0008] The thermoelectric power generation device substrate of the present invention is a flexible substrate having a sheet-like insulating base material and a metal layer formed on one side of the base material, wherein a cell substrate portion is formed on the flexible substrate, and the cell substrate portion comprises a strip-shaped first beam portion, one end of which is connected in the width direction to one end of the first beam portion and a strip-shaped first leg portion extending parallel to the first beam portion toward the center of the first beam portion, and one end of which is connected in the width direction to the other end of the first beam portion and a strip-shaped first The structure has two legs, a first contact portion connected in the width direction to the other end of the first leg on the opposite side of the first beam and in contact with the heat source, and a second contact portion connected in the width direction to the other end of the second leg on the opposite side of the first beam and in contact with the heat source. The first and second legs deform and stand upright by widening the distance between the first and second contact portions, so that in the thickness direction of the substrate, one end of the first leg and one end of the second leg move away from the first and second contact portions together with the first beam.
[0009] The thermoelectric power generation device of the present invention comprises a substrate for a thermoelectric power generation device in which a plurality of cell substrate portions as described above are formed in a continuous manner, and a thermoelectric element. [Effects of the Invention]
[0010] According to the present invention, the contact area with the heat source can be increased to improve power generation efficiency, and because the first and second legs of the cell substrate rise up and become three-dimensional when the substrate for the thermoelectric power generation device is pulled, multiple cell substrates can be made three-dimensional all at once, whether there is one cell substrate unit or multiple cell substrates connected in series. [Brief explanation of the drawing]
[0011] [Figure 1] This is a perspective view showing a three-dimensional thermoelectric power generation device according to an embodiment. [Figure 2] This is an exploded perspective view showing a power generation cell in a flat plate configuration. [Figure 3] This is a perspective view showing a three-dimensional power generation cell. [Figure 4]It is a plan view showing a thermoelectric power generation device in a flat state where power generation cells are arranged in 3 rows and 3 columns. [Figure 5] It is a circuit diagram showing the circuit of the thermoelectric power generation device. [Figure 6] It is a perspective view showing an example of a power generation cell forming two unit circuits. [Figure 7] It is a perspective view showing an example of a power generation cell in which two unit circuits are connected in series. [Figure 8] It is a perspective view showing another example of a power generation cell forming two unit circuits. [Figure 9] It is a plan view showing a thermoelectric power generation device in a flat state where 18 unit circuits are connected in series using 9 power generation cells. [Figure 10] It is a circuit diagram showing the circuit of the thermoelectric power generation device of FIG. 9. [Figure 11] It is a plan view showing a thermoelectric power generation device in a flat state where 15 unit circuits are connected in series using 9 power generation cells. [Figure 12] It is a circuit diagram showing the circuit of the thermoelectric power generation device of FIG. 11. [Figure 13] It is a perspective view showing a power generation cell having a two-pin configuration. [Figure 14] It is a plan view showing the cell substrate portion of the power generation cell of FIG. 13. [Figure 15] It is a perspective view showing another example of a power generation cell having a four-pin configuration. [Figure 16] It is a plan view showing the cell substrate portion of the power generation cell of FIG. 15. [Figure 17] It is a graph showing the results of measuring the heights of both ends of each beam portion when the substrate for a thermoelectric power generation device composed of 5 power generation cells is three-dimensionalized. [Figure 18] It is a graph showing the results of measuring the power generation ability of one power generation cell. [[ID=~45]]
Embodiments for Carrying Out the Invention
[0012] In Figure 1, the thermoelectric power generation device 10 is used by being attached to the surface Hs of a heat source such as an engine, pipes, or electronic equipment (hereinafter referred to as the heat source surface). The thermoelectric power generation device 10 consists of multiple thermoelectric elements Gp and Gn (see Figure 2) fixed to a flat wiring board 11, and is attached to the heat source surface Hs in a three-dimensional state from its flat form. The thermoelectric power generation device 10 in this example consists of multiple power generation cells 12. The power generation cell 12 is the unit configuration of the thermoelectric power generation device 10, and in this example, the power generation cells 12 are arranged in a 3x3 configuration.
[0013] In the following description, the thermoelectric power generation device 10 is assumed to be mounted on a heat source surface Hs, which is a planar heat source. However, this does not limit the orientation of the thermoelectric power generation device 10 relative to the heat source surface Hs. Also, as an example, the heat source surface Hs is described as a plane, but this does not limit the heat source surface Hs on which the thermoelectric power generation device 10 is mounted to a plane.
[0014] The wiring board 11, used as a substrate for a thermoelectric power generation device, has a structure in which a metal layer 16 is formed on the upper surface of a base film 15, which is a sheet-like insulating substrate, and is flexible. The base film 15 is made of an insulating resin, in this example polyimide. In this example, the base film 15 is flexible, and the flexibility of the wiring board 11 is mainly due to the flexibility of the base film 15. The metal layer 16 is made of a metal with high thermal conductivity and electrical conductivity, in this example copper (Cu).
[0015] The base film 15 only needs to have insulating properties on at least the side facing the metal layer 16. The base film 15 may also be made of a material other than resin, and may consist of multiple layers made of different materials. Furthermore, since the heat from the heat source surface Hs is transferred to the metal layer 16 via the base film 15, the base film 15 is preferably made of a material with high thermal conductivity. The metal layer 16 may be made of a material with high thermal conductivity and electrical conductivity, such as aluminum (Al) or gold (Au).
[0016] In Figure 2, one power generation cell 12 consists of a cell substrate portion 11a formed on a wiring board 11 and two thermoelectric elements Gp and Gn, respectively. Note that in Figure 2, the cell substrate portion 11a is depicted as a flat plate rather than a three-dimensional structure on the wiring board 11.
[0017] The cell substrate portion 11a has a beam portion 20, first to fourth leg portions 21 to 24, a first contact portion 25, and a second contact portion 26. The beam portion 20, first to fourth leg portions 24, first contact portion 25, and second contact portion 26 are formed by creating straight cut lines C1 to C10 on the rectangular cell substrate portion 11a according to their shapes. In addition, insulating regions 21a to 24a are formed on the first to fourth leg portions 21 to 24, respectively. In this example, the cell substrate portion 11a has a metal layer 16 provided over its entire surface except for the insulating regions 21a to 24a.
[0018] The cut lines C1 to C10 are for separating the adjacent cell substrate portion 11a on either side of them. The method for forming the cut lines C1 to C10 is not particularly limited, and a method appropriate to the materials of the base film 15 and the metal layer 16 may be used. For example, the cut lines C1 to C10 can be formed by laser processing. During manufacturing, the cut lines C1 to C10 do not need to completely separate the adjacent regions on either side of them. For example, when mounting the thermoelectric power generation device 10 to the heat source surface Hs, that is, when creating the thermoelectric power generation device 10 in three dimensions, the cut lines C1 to C10 may be made into groove-like cuts that allow for easy separation at that point.
[0019] The beam portion 20 is formed by cut lines C1 and C2 in the center of the cell substrate portion 11a, extending in a band shape parallel to one side of the cell substrate portion 11a with a predetermined width. When the power generation cell 12 is assembled in three dimensions, this beam portion 20 is raised to a position higher than the first contact portion 25 and the second contact portion 26, and floats above the heat source surface Hs. The beam portion 20 functions as a heat sink in the power generation cell 12.
[0020] In the following description, the direction connecting one end and the other end of the beam portion 20 in the flat cell substrate portion 11a (the longitudinal direction in this example) is referred to as the X direction, the width direction of the beam portion 20 perpendicular to the X direction is referred to as the Y direction, and the thickness direction of the cell substrate portion 11a is referred to as the Z direction. In this example, the beam portion 20 is a long strip in the X direction, and the width of the beam portion 20 may be greater than its length in the X direction.
[0021] On one end of the beam section 20 in the X direction (left side in Figure 2), the first leg section 21 and the third leg section 23 are formed, flanking the beam section 20, and on the other end (right side in Figure 2), the second leg section 22 and the fourth leg section 24 are formed, flanking the beam section 20. In the width direction of the beam section 20, the first leg section 21 and the second leg section 22 are located on one side (front side in Figure 2), and the third leg section 23 and the fourth leg section 24 are located on the other side (back side in Figure 2). In this example, the first leg section 21 to the fourth leg section 24 are all strip-shaped with a length of 1 / 2 the length of the beam section 20.
[0022] The first leg portion 21 has one end (tip) connected to one end of the beam portion 20 in the Y direction, and extends in a strip shape parallel to the beam portion 20 to the center of the cell substrate portion 11a (beam portion 20) in the X direction. Therefore, the cut line C1 that separates the beam portion 20 from the first leg portion 21 and the second leg portion 22 in the Y direction is not formed at the boundary between one end of the beam portion 20 and one end of the first leg portion 21. As a result, one end of the beam portion 20 and one end of the first leg portion 21 are connected and not separated. Note that the connection between the ends means that the side edges of the ends are connected and become one unit.
[0023] The second leg portion 22 is on the extension of the first leg portion 21, with one end (tip) connected to the other end of the beam portion 20 in the Y direction, and extending in a strip shape parallel to the beam portion 20 to the center of the cell substrate portion 11a (beam portion 20) in the X direction. For this reason, the aforementioned cut line C1 is not formed at the boundary between the other end of the beam portion 20 and one end of the second leg portion 22. As a result, the beam portion 20 and the second leg portion 22 are connected without being separated. The other end (base end) of the first leg portion 21 and the other end (base end) of the second leg portion 22 are separated by a cut line C3 formed in the Y direction.
[0024] The third leg portion 23 is similar to the first leg portion 21, but on the opposite side in the Y direction from the first leg portion 21, one end (tip) is connected to one end of the beam portion 20. The fourth leg portion 24 is an extension of the third leg portion 23. This fourth leg portion 24 is similar to the second leg portion 22, but on the opposite side in the Y direction from the second leg portion 22, one end (tip) is connected to the other end of the beam portion 20. In other words, one end of the beam portion 20 and one end of the third leg portion 23 are not separated by the cut line C2, and the other end of the beam portion 20 and one end of the fourth leg portion 24 are not separated by the cut line C2. The other end (base end) of the third leg portion 23 and the other end (base end) of the fourth leg portion 24 are separated by a cut line C4 formed in the width direction.
[0025] As can be seen from the above explanation, cut line C1 is formed at the boundary between the beam section 20 and the first leg section 21 and the second leg section 22, excluding the boundary between one end of the beam section 20 and the other ends of the first leg section 21 and the second leg section 22. Also, cut line C2 is formed at the boundary between the beam section 20 and the third leg section 23 and the fourth leg section 24, excluding the boundary between one end of the beam section 20 and the other ends of the third leg section 23 and the fourth leg section 24.
[0026] The first to fourth legs 21 to 24 raise one end of each leg by increasing the distance between the other ends of the first leg 21 and the third leg 23 and the other ends of the second leg 22 and the fourth leg 24, thereby causing the beam 20 to float. This is because one end of the first leg 21 and the third leg 23, and the second leg 22 and the fourth leg 24, are connected to both ends of a beam 20 of a certain length.
[0027] The first contact portion 25 and the second contact portion 26 are in surface contact with the heat source surface Hs. The first contact portion 25 is formed in a "U" shape and consists of a strip-shaped first region 25a located on the outside of the first leg portion 21 (opposite side from the beam portion 20) and extending parallel to the first leg portion 21 toward one end of the first leg portion 21, a strip-shaped second region 25b located on the outside of the third leg portion 23 and extending parallel to the third leg portion 23 toward one end of the first leg portion 21, and a strip-shaped third region 25c extending in the Y direction connecting the first region 25a and the second region 25b.
[0028] One end of the first region 25a (one end of the first contact portion 25) is connected to the other end of the first leg portion 21 in the Y direction. Similarly, one end of the second region 25b (the other end of the first contact portion 25) is connected to the other end of the third leg portion 23 in the Y direction. Therefore, the cut line C5 separating the first leg portion 21 and the first region 25a in the Y direction is formed at the boundary between the first leg portion 21 and the first contact portion 25, excluding the boundary between the other end of the first leg portion 21 and one end of the first contact portion 25. Also, the cut line C6 separating the third leg portion 23 and the second region 25b in the Y direction is formed at the boundary between the third leg portion 23 and the first contact portion 25, excluding the boundary between the other end of the third leg portion 23 and one end of the second region 25b. As a result, the other end of the first leg portion 21 and one end of the first contact portion 25, and the other end of the third leg portion 23 and the other end of the first contact portion 25, remain connected without being separated.
[0029] The third region 25c is formed as a strip extending in the Y direction outward in the X direction from one end of each of the first leg portion 21, beam portion 20, and third leg portion 23. A cut line C7 is formed at the boundary extending in the Y direction between this third region 25c and one end of each of the first leg portion 21, beam portion 20, and third leg portion 23. Therefore, cut lines C5 to C7 form a single "U" shaped cut line.
[0030] The second contact portion 26 is formed in a "U" shape, similar to the first contact portion 25, and consists of a strip-shaped first region 26a located on the outside of the second leg portion 22 (opposite side from the beam portion 20) and extending parallel to the second leg portion 22 toward one end of the second leg portion 22, a strip-shaped second region 26b located on the outside of the fourth leg portion 24 and extending parallel to the fourth leg portion 24 toward one end of the fourth leg portion 24, and a strip-shaped third region 26c extending in the Y direction that connects the first region 26a and the second region 26b.
[0031] One end of the first region 26a (one end of the second contact portion 26) is connected to the other end of the second leg portion 22 in the Y direction, and one end of the second region 26b (the other end of the second contact portion 26) is connected to the other end of the fourth leg portion 24 in the Y direction. Therefore, the cut line C8 that separates the second leg portion 22 and the first region 26a in the Y direction is formed at the boundary between the second leg portion 22 and the second contact portion 26, excluding the boundary between the other end of the second leg portion 22 and one end of the second contact portion 26. Similarly, the cut line C9 that separates the fourth leg portion 24 and the second region 26b in the Y direction is formed at the boundary between the fourth leg portion 24 and the second contact portion 26, excluding the boundary between the other end of the fourth leg portion 24 and one end of the second region 26b. As a result, the other end of the second leg portion 22 and one end of the second contact portion 26, and the other end of the fourth leg portion 24 and the other end of the second contact portion 26, remain connected without being separated.
[0032] The third region 26c is formed in a strip shape extending in the Y direction, outside the X direction of one end of the second leg portion 22, the other end of the beam portion 20, and one end of the fourth leg portion 24. A cut line C10 is formed at the boundary extending in the Y direction between this third region 26c and one end of the second leg portion 22, the other end of the beam portion 20, and one end of the fourth leg portion 24. Therefore, cut lines C8 to C10 form a single "U" shaped cut line.
[0033] In this example, the shape of the cell substrate portion 11a, in which each part is formed as described above, when viewed from above is symmetrical with respect to the center line in the Y direction of the cell substrate portion 11a, and also symmetrical with respect to the center line in the X direction.
[0034] An insulating region 21a is provided between one end and the other end of the first leg portion 21, in this example, approximately in the center of the longitudinal direction of the first leg portion 21. This insulating region 21a is formed as a region on the base film 15 where there is no metal layer 16, and electrically isolates the metal layer 16 in the first leg portion 21. That is, in the first leg portion 21, the insulating region 21a electrically separates the metal layer 16 into one end side and the other end side. Similarly to the first leg portion 21, insulating regions 22a to 24a are provided approximately in the center of the longitudinal direction of the second to fourth leg portions 22 to 4th leg portions 24. These insulating regions 21a to 24a electrically divide the metal layer 16 into a beam portion region connected to the beam portion 20, a first heat source side region connected to the first contact portion 25, and a second heat source side region connected to the second contact portion 26.
[0035] The method for forming the insulating regions 21a to 24a is not particularly limited. For example, the insulating regions 21a to 24a can be formed by etching the metal layer 16, or when forming the metal layer 16 on the surface of the base film 15 by vapor deposition or plating, the areas that will become the insulating regions 21a to 24a can be masked to prevent the formation of the metal layer 16. Alternatively, a thin metal film without the insulating regions 21a to 24a can be attached to the base film 15 as the metal layer 16.
[0036] Thermoelectric element Gp is a p-type thermoelectric element, and thermoelectric element Gn is an n-type thermoelectric element. In this example, the two thermoelectric elements Gp are positioned to straddle the insulating regions 21a and 23a, and are soldered to the metal layer 16 on one end (beam region) and the metal layer 16 on the other end (first heat source region) of the first leg 21 and third leg 23, respectively, and mounted on the first leg 21 and third leg 23. The two thermoelectric elements Gn are positioned to straddle the insulating regions 22a and 24a, and are soldered to the metal layer 16 on one end (beam region) and the metal layer 16 on the other end (second heat source region) of the second leg 22 and fourth leg 24, respectively, and mounted on the second leg 22 and fourth leg 24. In this way, the thermoelectric elements Gp and Gn are mounted on a flat wiring board 11, making mounting easy.
[0037] As described above, by connecting the thermoelectric elements Gp and Gn, in one power generation cell 12, two thermoelectric elements Gp connected in parallel and two thermoelectric elements Gn connected in parallel are connected in series. When the temperature of the other end of the first leg portion 21 to the fourth leg portion 24 is raised higher than the temperature of one end, the thermoelectric elements Gp and Gn generate an electromotive force in which the first contact portion 25 becomes the positive electrode and the second contact portion 26 becomes the negative electrode.
[0038] Furthermore, it is preferable that the mounting positions of the thermoelectric elements Gp and Gn, i.e., the formation positions of the insulating regions 21a to 24a, be in the flat areas rather than the curved areas of the first to fourth legs 21 to 24. This prevents the thermoelectric elements Gp and Gn from falling off. Also, from the viewpoint of increasing the temperature difference between the thermoelectric elements Gp and Gn by keeping them away from the heat source surface Hs, it is preferable to position them closer to one end, away from the other end of the first to fourth legs 21 to 24.
[0039] By pulling the cell substrate 11a in the X direction so that the first contact portion 25 and the second contact portion 26 of the cell substrate 11a are moved away from each other, that is, the first contact portion 25 is moved to the left and the second contact portion 26 is moved to the right in Figure 2, thereby increasing the distance between them, the power generation cell 12 becomes three-dimensional.
[0040] As described above, when the cell substrate portion 11a is pulled, a force acts on the other ends of the first leg portion 21 and the third leg portion 23 and the other ends of the second leg portion 22 and the fourth leg portion 24 in a direction that widens the gap between them. On the other hand, one end of the first leg portion 21 and the third leg portion 23 is connected to one end of the beam portion 20, and one end of the second leg portion 22 and the fourth leg portion 24 is connected to the other end of the beam portion 20. Therefore, when the above force acts on the other ends of the first to fourth leg portions 24, a force is generated in which one end of the first leg portion 21 and the third leg portion 23 and one end of the second leg portion 22 and the fourth leg portion 24 pull against each other via the beam portion 20. As a result, the first to fourth leg portions 24 stand up, and the beam portion 20 floats up. For example, by placing a wiring board 11 on a flat plate and pulling both ends of the wiring board 11, the beam portion 20 can be moved upward (in the opposite direction to the flat plate), thereby making all the power generation cells 12 three-dimensional.
[0041] As shown in Figure 3, the three-dimensional power generation cell 12 has a shape in which the first leg portion 21 and the third leg portion 23 rise from the other end connected to the first contact portion 25, and the second leg portion 22 and the fourth leg portion 24 rise from the other end connected to the second contact portion 26. In addition, a beam portion 20, whose ends are connected to one end of the first leg portion 21 and the third leg portion 23 and one end of the second leg portion 22 and the fourth leg portion 24, is positioned higher than the other ends of the first to fourth leg portions 24 or the positions of the first contact portion 25 and the second contact portion 26. In the three-dimensional state of the power generation cell 12, the beam portion 20 will bend and twist depending on the mounting state of the first contact portion 25 and the second contact portion 26 to the heat source surface Hs, and the degree of these changes will also vary.
[0042] As shown in Figure 4, when the thermoelectric power generation device 10 is viewed in plan view without being made three-dimensional, in the thermoelectric power generation device 10, three cell substrate sections 11a are connected in both the X and Y directions, and the power generation cells 12 are arranged in a 3x3 matrix. In the X direction (row direction), adjacent cell substrate sections 11a are connected and integrated, with the third region 25c of the first contact section 25 in one cell substrate section 11a and the third region 26c of the second contact section 26 in the other cell substrate section 11a being connected. As a result, three power generation cells 12 are connected in series in the X direction.
[0043] Furthermore, adjacent cell substrates 11a in the Y direction (column direction) are connected and integrated, with the first region 25a of the first contact portion 25 in one cell substrate 11a and the second region 25b of the first contact portion 25 in the other cell substrate 11a being connected and integrated, and the first region 26a of the second contact portion 26 in one cell substrate 11a and the second region 26b of the second contact portion 26 in the other cell substrate 11a being connected and integrated. As a result, three power generation cells 12 are connected in parallel in the Y direction. The first contact portions 25 and the second contact portions 26 at both ends of the thermoelectric power generation device 10 in the X direction also function as a pair of electrodes for extracting power from the thermoelectric power generation device 10.
[0044] As described above, the thermoelectric power generation device 10, with the power generation cells 12 connected, forms a circuit in which three parallel-connected power generation cells 12 are connected in series, as shown in Figure 5. If we consider the thermoelectric elements Gp and Gn connected in series as one unit circuit, then in one power generation cell 12, two unit circuits are connected in parallel, and in the thermoelectric power generation device 10 as a whole, six unit circuits are connected in parallel, resulting in a circuit in which three of these six unit circuits are connected in series.
[0045] In Figure 5, the thermoelectric elements Gp and Gn are shown using battery circuit symbols for convenience. In these symbols, the relatively high-temperature side of thermoelectric element Gp is the positive electrode and the relatively low-temperature side is the negative electrode, while the relatively high-temperature side of thermoelectric element Gn is the negative electrode and the relatively low-temperature side is the positive electrode. Similarly, in Figures 10 and 12, the thermoelectric elements Gp and Gn are shown using battery circuit symbols for convenience.
[0046] When attaching the thermoelectric power generation device 10 to the heat source surface Hs, both ends of the wiring board 11 in the X direction are pulled. This pulling force acts on each cell substrate portion 11a formed on the wiring board 11, pulling the first contact portion 25 and the second contact portion 26 apart from each other. As a result, each of the power generation cells 12 formed on the wiring board 11 becomes three-dimensional simultaneously. Therefore, there is no need to individually three-dimensionalize the multiple power generation cells 12 provided on the thermoelectric power generation device 10, and three-dimensionalization of each power generation cell 12 of the thermoelectric power generation device 10 is easy.
[0047] The three-dimensional thermoelectric power generation device 10 is attached to the heat source surface Hs by, for example, attaching it, with the lower surfaces (the surfaces opposite to the metal layer 16) of each first contact portion 25 and each second contact portion 26 in close contact with the heat source surface Hs.
[0048] In the thermoelectric power generation device 10, the metal layer 16 primarily handles heat conduction, transferring heat from the heat source surface Hs through the metal layer 16 on the other end sides of the first to fourth legs 21 to 24 via the first and second contact portions 25 and 26, thereby raising the temperature of one end of the thermoelectric elements Gp and Gn. Furthermore, by dissipating heat from the thermoelectric elements Gp and Gn through the metal layer 16 on the other end sides of the first to fourth legs 24 via the beam portion 20, the temperature of the other end of the thermoelectric elements Gp and Gn is effectively lowered. In this way, a temperature difference is generated between the thermoelectric elements Gp and Gn, and the electromotive force generated in the thermoelectric power generation device 10 is extracted from the first and second contact portions 25 and 26 at both ends in the X direction. As described above, the thermoelectric power generation device 10 in this example is a circuit in which three parallel circuits of six unit circuits are connected in series. Therefore, compared to the case where one unit circuit is used, six times the current and three times the voltage are obtained, and as a result, 18 times the power is obtained.
[0049] Furthermore, since the beam section 20 is levitated by the first to fourth legs 21 to 24, the beam section 20, which acts as a low-temperature source, can be moved far away from the heat source surface Hs, thus achieving high power generation efficiency. In addition, since the thermoelectric elements Gp and Gn are moved far above the heat source surface Hs, even higher power generation efficiency can be achieved.
[0050] The thermoelectric power generation device 10, having the structure described above, has the freedom to deform the wiring board 11 without applying a force that would cause the thermoelectric elements Gp and Gn to fall off, and has a large degree of freedom in the shape of the heat source surface Hs to which it can be mounted. For this reason, the thermoelectric power generation device 10 can be mounted on curved surfaces, such as cylindrical or spherical surfaces, to obtain high power generation efficiency.
[0051] By forming an insulating region (hereinafter referred to as the insulating region for connection patterns) in the metal layer 16 of the power generation cell 12, separate from the insulating regions 21a to 24a, various connection configurations for the thermoelectric elements Gp and Gn in the power generation cell 12 can be achieved. Hereafter, when thermoelectric elements Gp and Gn are not distinguished, they will be described as thermoelectric element G.
[0052] The power generation cell 12A in Figure 6 forms two electrically isolated unit circuits. Specifically, a thermoelectric element G provided on the first leg portion 21 and a thermoelectric element G provided on the second leg portion 22 are connected in series to form one unit circuit, and separately, a thermoelectric element G provided on the third leg portion 23 and a thermoelectric element G provided on the fourth leg portion 24 are connected in series to form another unit circuit, and these unit circuits are electrically isolated by the insulating regions 40a to 40c for the connection pattern.
[0053] The insulating region 40a for the connection pattern is formed extending in the X direction of the beam portion 20 so as to pass through the center of the beam portion 20 in the width direction, and electrically isolates the metal layer 16 on one end side of the first leg portion 21 and the third leg portion 23. The insulating region 40b for the connection pattern is formed in the third region 25c of the first contact portion 25, and electrically isolates the metal layer 16 in the first contact portion 25 from the other end side of the first leg portion 21 and the other end side of the third leg portion 23. Similarly, the insulating region 40c for the connection pattern is formed in the third region 26c of the second contact portion 26, and electrically isolates the metal layer 16 in the second contact portion 26 from the other end side of the second leg portion 22 and the other end side of the fourth leg portion 24. In the power generation cell 12A, the first leg portion 21 and the third leg portion 23 may be provided with thermoelectric elements G of different types (p-type or n-type), and similarly, the second leg portion 22 and the fourth leg portion 24 may be provided with thermoelectric elements G of different types.
[0054] The power generation cell 12B shown in Figure 7 is configured to connect two unit circuits in series. This power generation cell 12B is the same as the power generation cell 12A shown in Figure 6, except that the third region 26c of the second contact portion 26 does not have an insulating region for the connection pattern. In the power generation cell 12B, the same type of thermoelectric element G is provided on the first leg portion 21 and the fourth leg portion 24, while a different type of thermoelectric element G is provided on the second leg portion 22 and the third leg portion 23. As a result, a unit circuit consisting of the thermoelectric element G provided on the first leg portion 21 and the thermoelectric element G provided on the second leg portion 22 and a unit circuit consisting of the thermoelectric element G provided on the third leg portion 23 and the thermoelectric element G provided on the fourth leg portion 24 are connected in series by the second contact portion 26.
[0055] The power generation cell 12C shown in Figure 8, like the power generation cell 12A shown in Figure 6, forms two electrically separated unit circuits, but with the thermoelectric elements G in the first leg 21 and the third leg 23 forming one unit circuit, and the thermoelectric elements G in the second leg 22 and the fourth leg 24 forming another unit circuit. This power generation cell 12C has an insulating region 40e for connection patterns extending in the Y direction at the center of the beam portion 20 in the X direction. This electrically isolates the metal layer 16 on one end of the first leg portion 21 and the third leg portion 23 from the metal layer 16 on one end of the second leg portion 22 and the fourth leg portion 24. An insulating region 40b for connection patterns is formed at the first contact portion 25, and an insulating region 40c for connection patterns is formed at the second contact portion 26. In the power generation cell 12C, the first leg portion 21 and the third leg portion 23 may be equipped with thermoelectric elements G of different types (p-type or n-type), and similarly, the second leg portion 22 and the fourth leg portion 24 may be equipped with thermoelectric elements G of different types.
[0056] By combining the power generation cells 12, 12A, 12B, 12C, etc. as described above, a thermoelectric power generation device can be constructed by connecting multiple thermoelectric elements Gp and Gn in various connection configurations.
[0057] The thermoelectric power generation device 10A shown in Figure 9 is constructed by combining power generation cells 12A and 12B, and connecting 18 unit circuits in series. The circuit configuration of this thermoelectric power generation device 10A is shown in Figure 10. Note that Figure 9 depicts the thermoelectric power generation device 10A before it is assembled into a three-dimensional structure. Reference numeral 40 indicates the insulating region for the connection pattern, consisting of insulating regions 40a to 40c.
[0058] In this thermoelectric power generation device 10A, power generation cells 12A, 12A, and 12B are arranged in this order in the X direction, forming one row, and three rows are arranged in the Y direction and integrated. At the boundaries between rows of the thermoelectric power generation device 10A, insulating regions 42 are formed by removing the metal layer 16. These insulating regions 42 insulate adjacent power generation cells in the Y direction, but are not formed at the boundaries between the first contact portions 25 of adjacent power generation cells 12A in the Y direction at the X-direction end.
[0059] In this thermoelectric power generation device 10A, two series circuits, each consisting of three unit circuits in series within a single row, are connected in series by the second contact portion 26 of the power generation cell 12B. Furthermore, the series circuits in each row are further connected in series by the electrical connection between the first contact portions 25 of adjacent power generation cells 12A located at the ends in the X direction.
[0060] The thermoelectric power generation device 10B shown in Figure 11 is a circuit in which 15 unit circuits are connected in series by combining power generation cells 12A and 12C. The circuit configuration of this thermoelectric power generation device 10B is shown in Figure 12. Note that Figure 11 depicts the state of the thermoelectric power generation device 10B before it is made three-dimensional. In this thermoelectric power generation device 10B, power generation cells 12C, 12C, and 12A are arranged in this order in the Y direction, and three such rows are arranged in the X direction and integrated. An insulating region 43 is formed at the boundary between the rows, where the metal layer 16 has been removed. This insulating region 43 insulates adjacent power generation cells in the X direction, but it is not formed at part of the boundary between the first contact portion 25 and the second contact portion 26 of adjacent power generation cells 12C in the X direction at the Y direction end.
[0061] In this thermoelectric power generation device 10B, a series circuit is formed by connecting five unit circuits in series within a single row. Furthermore, the series circuits of each row are connected in series by the electrical connection between the first contact portion 25 and the second contact portion 26 of the adjacent power generation cell 12C located at the Y-direction end in the X-direction. Note that in this thermoelectric power generation device 10B, the thermoelectric elements Gp and Gn of the first leg portion 21 and the second leg portion 22 of each power generation cell 12A can be omitted.
[0062] In each of the above examples, one power generation cell has a four-legged configuration with first to fourth legs 21 to 24. However, as shown in Figure 13, a two-legged configuration is also possible, with a pair of legs (first leg 21 and second leg 22) provided on only one side of the beam 20. Figure 14 shows the flat cell substrate 11a corresponding to the power generation cell 12D before it is made three-dimensional, with the cut lines indicated by dashed lines. In the power generation cell 12D, both ends of the beam 20 are connected to one side of one end of the first leg 21 and the second leg 22. Furthermore, one end of the first contact portion 25 is connected to one side of the other end of the first leg portion 21 in a strip shape extending parallel to the first leg portion 21 toward one end of the first leg portion 21, and one end of the second contact portion 26 is connected to one side of the other end of the second leg portion 22 in a strip shape extending parallel to the second leg portion 22 toward one end of the second leg portion 22. This two-legged configuration is the minimum configuration for a power generation cell that becomes three-dimensional by tension.
[0063] Alternatively, as shown in Figure 15, the power generation cell 12E may be configured with two beam sections 20A and 20B, with one end of the first leg section 21 and one end of the second leg section 22 connected to both ends of beam section 20A, and one end of the third leg section 23 and one end of the fourth leg section 24 connected to both ends of beam section 20B. Figure 16 shows the flat cell substrate section 11a corresponding to the power generation cell 12E before it is made three-dimensional, with the cut lines indicated by dashed lines. In this power generation cell 12E, the other end of the first leg section 21 is connected to one side of the first contact section 25A, and the other end of the third leg section 23 is connected to the other side, the other end of the second leg section 22 is connected to one side of the second contact section 26A, and the other end of the fourth leg section 24 is connected to the other side. This power generation cell 12E has a shape that is symmetrical twice. Therefore, the first leg portion 21 and the second leg portion 22 are connected to the beam portion 20A on the rear side and the front side of the first contact portion 25A and the second contact portion 26A, respectively, in Figure 15, while the third leg portion 23 and the fourth leg portion 24 are connected to the beam portion 20B on the front side and the rear side of the first contact portion 25A and the second contact portion 26A, respectively, in Figure 15. It should be noted that this power generation cell 12E can also be provided with an insulating region for connection patterns, similar to power generation cells 12A to 12C.
[0064] A thermoelectric power generation device was fabricated by arranging five power generation cells 12 in the X direction and integrating them, and it was confirmed that it could be made into a three-dimensional structure. However, the thermoelectric elements Gp and Gn were not mounted when the device was fabricated. In the state before three-dimensionalization, the power generation cell 12 of the fabricated thermoelectric power generation device had a length of 38 mm in the X direction, a length of 18 mm in the Y direction, a Y direction length of 3 mm for the first leg 21 to the fourth leg 24, a length of 13 mm for the cut lines C5, C6, C8, and C9, a Y direction length of 7 mm for the beam 20, a X direction length of 3 mm for the part where the first leg 21, the third leg 23 and the first contact part 25 are connected, and a X direction length of 3 mm for the part where the second leg 22, the fourth leg 24 and the second contact part 26 are connected, and the X direction lengths of the third regions 25c and 26c of the first contact part 25 and the second contact part 26 were 3 mm. The wiring board 11 used a polyimide film with a thickness of 40 μm as the base film 15 and copper foil with a thickness of 50 μm as the metal layer 16. When a tension of 65 mm in the X direction was applied to the fabricated thermoelectric power generation device, the first to fourth legs 24 of each power generation cell 12 rose up, and the levitation of each beam 20 was confirmed.
[0065] As described above, the heights of one end and the other end of the beam portion 20 in each power generation cell 12 of the three-dimensional thermoelectric power generation device were measured. The height of one end of the beam portion 20 was defined as the height from the edge of the lowest third region 25c of the first contact portion 25, and the height of the other end of the beam portion 20 was defined as the height from the edge of the lowest third region 26c of the second contact portion 26. The measurement results of the heights are shown in Figure 17. The "Position number" on the horizontal axis of the graph in Figure 17 represents the measurement numbers of one end and the other end of the beam portion 20, which were assigned sequentially from one end to the other end of the thermoelectric power generation device. From these results, it was confirmed that each power generation cell 12 was uniformly deformed and three-dimensional.
[0066] The amount of power generated was measured for one power generation cell 12. The size of the power generation cell 12 is the same as that of the power generation cell 12 in the thermoelectric power generation device described above. Bi03Sb was used as the thermoelectric element Gp. 1.7Te3 was used as the material for the thermoelectric element Gn, and Bi2Te3+Ru was used as the thermoelectric element Gn. The size of both the thermoelectric elements Gp and Gn was 4mm × 3mm × 1mm (length in the X direction × length in the Y direction × length in the Z direction). The electrical resistance of the fabricated power generation cell 12 was 28.5mΩ. The first contact part 25 and the second contact part 26 were attached to the heat source surface Hs in a room maintained at a room temperature of 22°C. At this time, the distance between the first contact part 25 and the second contact part 26 was set to 13mm to create a three-dimensional power generation cell 12. The amount of power generated by the power generation cell 12 was measured when the temperature of the heat source surface Hs was 40°C, 70°C, and 100°C. The measurement results are shown in Figure 18. When the temperature of the heat source surface Hs was set to 40°C, 70°C, and 100°C, the maximum power generation was 63.36 μW, 469.1 μW, and 1162 μW, respectively, and the open-circuit voltages were 2.82 mV, 7.62 mV, and 12.6 mV, respectively, confirming that power generation was performed efficiently. [Explanation of Symbols]
[0067] 10, 10A, 10B Thermoelectric Power Generation Devices 11 Wiring board 11a Cell substrate section 12, 12A, 12B, 12C, 12D, 12E power generation cells 20, 20A, 20B beam section 21 1st leg 22 Second leg 23 Third leg 24 4th leg 25,25A 1st contact part 26, 26A 2nd contact part G, Gn, Gp thermoelectric elements
Claims
1. A substrate for a thermoelectric power generation device, comprising a flexible substrate having a sheet-like insulating base material and a metal layer formed on one side of the base material, wherein a cell substrate portion is formed on the flexible substrate, The cell substrate portion is A strip-shaped first beam section, One end of the first leg portion is connected in the width direction to one end of the first beam portion, and the first leg portion is a strip-shaped portion that extends parallel to the first beam portion toward the center of the first beam portion, One end of the second leg portion is connected in the width direction to the other end of the first beam portion, and the second leg portion is a strip-shaped portion that extends parallel to the first beam portion toward the center of the first beam portion, It has a first contact portion that is connected in the width direction to the other end of the first leg portion on the opposite side of the first beam portion and in contact with the heat source, and a second contact portion that is connected in the width direction to the other end of the second leg portion on the opposite side of the first beam portion and in contact with the heat source, The first leg portion and the second leg portion deform and stand upright by widening the gap between the first contact portion and the second contact portion, so that in the thickness direction of the substrate, one end of the first leg portion and one end of the second leg portion move away from the first contact portion and the second contact portion together with the first beam portion. A substrate for thermoelectric power generation devices characterized by the following features.
2. The cell substrate portion is One end of the third leg portion is connected to the other end of the first beam portion on the side opposite to the first leg portion in the width direction, and the third leg portion is a strip-shaped portion that extends parallel to the first beam portion toward the center of the first beam portion, One end of the first beam is connected to the other end of the first leg in the width direction, on the opposite side from the second leg, and the fourth leg is a strip-shaped part that extends parallel to the first beam toward the center of the first beam. It has, The first contact portion is connected to the other end of the third leg portion, The second contact portion is connected to the other end of the fourth leg portion, The third and fourth legs deform and stand upright by widening the gap between the first and second contact portions, so that together with the first and second legs, in the thickness direction of the substrate, one end of the third leg and one end of the fourth leg move away from the first and second contact portions, together with the first beam portion. A substrate for a thermoelectric power generation device according to feature 1.
3. The cell substrate portion is A strip-shaped second beam section, A strip-shaped third leg portion, one end of which is connected in the width direction to one end of the second beam portion, extends parallel to the second beam portion toward the center of the second beam portion, and the other end of which is connected to the first contact portion in the width direction on the opposite side from the first leg portion, A strip-shaped fourth leg portion, one end of which is connected in the width direction to the other end of the second beam portion, extends parallel to the second beam portion toward the center of the second beam portion, and the other end of which is connected to the second contact portion on the side opposite to the second leg portion in the width direction. Having One end of the third leg is connected to the second beam on the side opposite to the first contact portion in the width direction. One end of the fourth leg is connected on the side opposite to the second contact portion in the width direction, and on the same side as the second beam to which the third leg of the second beam is connected. The third and fourth legs deform and stand upright by widening the gap between the first and second contact portions, so that, together with the first and second legs, in the thickness direction of the substrate, one end of the third leg and one end of the fourth leg move away from the first and second contact portions, together with the second beam portion. A substrate for a thermoelectric power generation device according to feature 1.
4. A plurality of the cell substrate portions are formed, connected in the direction of extension of the first beam portion, and the first contact portion of one of the cell substrate portions is connected to the second contact portion of another one of the cell substrate portions. A substrate for a thermoelectric power generation device according to claim 2 or 3.
5. A substrate for a thermoelectric power generation device according to claim 4, The first thermoelectric element is provided on each of the first legs, The second thermoelectric element is provided on each of the second legs and A third thermoelectric element is provided on each of the three legs, A fourth thermoelectric element is provided on each of the fourth legs and A thermoelectric power generation device characterized by comprising the following features.