Thermoelectric conversion element, thermoelectric conversion module, and manufacturing method thereof

Abstract

To provide a thermoelectric conversion module with a low electric resistance.SOLUTION: A thermoelectric conversion module comprises a plurality of lengthy thermoelectric conversion elements electrically connected in series to one another, the lengthy thermoelectric conversion elements comprising at least one kind of thermoelectric conversion element (A) selected from the group consisting of a thermoelectric conversion element (a1) that comprises a lengthy thermoelectric conversion structure body that has a slit extending in a longitudinal direction, and has two ends terminated in the thermoelectric conversion structure body, a thermoelectric conversion element (a2) that comprises a length thermoelectric conversion structure body having at least one slit that extends in the longitudinal direction and has a first end terminated in the thermoelectric conversion structure and an opened second end, and a junction part that is electrically connected to the end on a side where the slit of the thermoelectric conversion structure is opened over an opening of the slit, and a thermoelectric conversion element (a3) that comprises a plurality of lengthy thermoelectric conversion structure bodies disposed in parallel in a direction perpendicular to the longitudinal direction, each of which has a first end and a second end, and a first junction part and a second junction parts that electrically connect the first and the second ends to one another respectively.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermoelectric conversion element and a method for manufacturing the same, and a thermoelectric conversion module and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as one type of thermoelectric element that converts heat into electric power, a thermoelectric conversion element that converts heat into electric power by utilizing a temperature difference between both ends is known.

[0003] Thermoelectric conversion elements are used for power generation as thermoelectric conversion modules in which a plurality of thermoelectric conversion elements are connected in series or in parallel (see, for example, Patent Document 1 and Non-Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 121133 [Non-patent literature]

[0005] [Non-Patent Document 1] National Institute of Advanced Industrial Science and Technology, "Development of conductive polymer thin film with high thermoelectric conversion performance," AIST press release, [online], August 31, 2012, [Retrieved August 17, 2020], Internet<https: / / www.aist.go.jp / aist_j / press_release / pr2012 / pr20120831 / pr20120831.html> Summary of the Invention [Problem to be solved by the invention]

[0006] From the viewpoint of generating electricity more efficiently, it is necessary to reduce the electrical resistance of the thermoelectric conversion elements used in the thermoelectric conversion module.

[0007] Therefore, there has been a demand for a thermoelectric conversion element having a lower electrical resistance when compared with other elements having the same dimensions, and a thermoelectric conversion module using such a thermoelectric conversion element. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and have found that cutting a long thermoelectric conversion element in the longitudinal direction to form gaps extending in the longitudinal direction, or forming slits extending in the longitudinal direction and at least one end of which terminates within the thermoelectric conversion element, to form a thermoelectric conversion element having a plurality of current paths each having a width narrower than the width of the thermoelectric conversion element, reduces electrical resistance compared to a thermoelectric conversion element of the same width that does not have slits or gaps, and have completed the present invention.

[0009] That is, the present invention has an object to advantageously solve the above-mentioned problems, and the thermoelectric conversion module of the present invention is a thermoelectric conversion module (hereinafter, sometimes referred to as a "series-connected thermoelectric conversion module") including a plurality of long thermoelectric conversion elements electrically connected in series via their longitudinal ends, wherein the plurality of thermoelectric conversion elements electrically connected in series include one or more thermoelectric conversion elements (A) of at least one type selected from the group consisting of thermoelectric conversion elements (a1) to (a3), and the thermoelectric conversion element (a1) is an elongated thermoelectric conversion structure formed with at least one slit extending in the longitudinal direction and terminating at both ends within the thermoelectric conversion structure. The thermoelectric conversion element (a2) comprises a long thermoelectric conversion structure having at least one slit extending in the longitudinal direction, one end of which terminates within the thermoelectric conversion structure and the other end of which is open, and a junction that electrically connects the ends of the thermoelectric conversion structure on the side where the slit is open, across the opening of the slit; and the thermoelectric conversion element (a3) ​​comprises a plurality of long thermoelectric conversion structures arranged in parallel with gaps in a direction perpendicular to the longitudinal direction, a first junction that electrically connects the ends of the thermoelectric conversion structures on one longitudinal end side, and a second junction that electrically connects the ends of the thermoelectric conversion structures on the other longitudinal end side. Thus, if the thermoelectric conversion module has at least one thermoelectric conversion element (A) selected from the group consisting of the thermoelectric conversion elements (a1) to (a3), the electrical resistance can be reduced and the power generation efficiency of the thermoelectric conversion module can be increased.

[0010] Here, in the thermoelectric conversion module of the present invention, the thermoelectric conversion element (A) satisfies the following relational formula (1): S < W / n (1) (In formula (1), n ​​is the number of slits or gaps, S is the total width of the slits or gaps, and W is the width of the thermoelectric conversion element (A).) It is preferable that the following is satisfied. The relational expression (1) is an index that determines the processability of the slits or gaps, and W or n can be set according to the width of the slits or gaps that can be formed in the patterning process actually performed when fabricating the thermoelectric conversion element (A).

[0011] Furthermore, in the thermoelectric conversion module of the present invention, the thermoelectric conversion elements (a1) and (a2) have the same width dimension at the portions located on both sides of the slit in the width direction, the thermoelectric conversion elements (a3) ​​have the same width dimension at the portions located on both sides of the slit in the width direction, and the thermoelectric conversion elements (A) have the same width dimension at the portions located on both sides of the slit in the width direction, and the thermoelectric conversion elements (A) satisfy the following relational expression (2) in addition to the above-mentioned relational expression (1): R < Rn / n (2) (In formula (2), n is the number of slits or gaps, R is the electrical resistance of a hypothetical thermoelectric conversion element consisting of a long thermoelectric conversion structure having the same width, length, and thickness as the thermoelectric conversion element (A) and no slits or gaps, and Rn is the electrical resistance of the portions located on both sides of the slit in the width direction when the thermoelectric conversion element (A) is the thermoelectric conversion element (a1) or the thermoelectric conversion element (a2), and is the electrical resistance of the long thermoelectric conversion structure when the thermoelectric conversion element (A) is the thermoelectric conversion element (a3).) It is preferable that the following relational expression (2) is satisfied. If a thermoelectric conversion element (A) that satisfies the relational expression (2) is used, the electrical resistance of the thermoelectric conversion module can be further reduced.

[0012] Furthermore, in the thermoelectric conversion module of the present invention, it is preferable that the thermoelectric conversion element (A) has two or more slits or gaps, and that all of the slits or gaps have the same shape. If all of the slits or gaps have the same shape, production is easy and the uniformity of the thermoelectric conversion elements can be improved.

[0013] In the thermoelectric conversion module of the present invention, the long thermoelectric conversion structure is preferably configured so that the conductive material is arranged in a non-oriented state. If the thermoelectric conversion structure constituting the thermoelectric conversion element (A) is configured so that the conductive material is arranged in a non-oriented state, the electrical resistance of the thermoelectric conversion element (A) can be further reduced.

[0014] Here, from the viewpoint of further reducing the electrical resistance of the thermoelectric conversion element (A), the conductive material is preferably a fibrous carbon material, more preferably a carbon nanotube.

[0015] The present invention also aims to advantageously solve the above-mentioned problems, and the thermoelectric conversion element of the present invention is characterized in that it comprises a long thermoelectric conversion structure having at least one slit formed therein, the slit extending in the longitudinal direction of the thermoelectric conversion structure and having both ends terminated within the thermoelectric conversion structure. In this way, if the thermoelectric conversion structure has a slit extending in the longitudinal direction of the thermoelectric conversion structure and both ends terminating within the thermoelectric conversion structure, the electrical resistance will be lower than that of a thermoelectric conversion element made of a thermoelectric conversion structure without a slit.

[0016] Furthermore, the present invention aims to advantageously solve the above-mentioned problems, and is characterized in that the thermoelectric conversion element of the present invention comprises a long thermoelectric conversion structure having at least one slit formed therein, the slit extending in the longitudinal direction of the thermoelectric conversion structure, one end terminating within the thermoelectric conversion structure and the other end being open, and further comprising a junction portion that electrically connects the end of the thermoelectric conversion structure on the side where the slit is open across the opening of the slit. In this way, if the thermoelectric conversion structure has a slit that extends in the longitudinal direction of the thermoelectric conversion structure, one end of which terminates within the thermoelectric conversion structure and the other end of which is open, the electrical resistance will be lower than that of a thermoelectric conversion element made of a thermoelectric conversion structure that does not have a slit.

[0017] The present invention also aims to advantageously solve the above-mentioned problems, and the thermoelectric conversion module of the present invention is a thermoelectric conversion module (hereinafter sometimes referred to as a "parallel-connected thermoelectric conversion module") having a plurality of elongated thermoelectric conversion elements electrically connected in parallel via their longitudinal ends, characterized in that the plurality of thermoelectric conversion elements electrically connected in parallel include one or more of the thermoelectric conversion elements of the present invention described above. In this way, by using the above-described thermoelectric conversion element having a thermoelectric conversion structure with slits, it is possible to reduce electrical resistance and increase the power generation efficiency of the thermoelectric conversion module.

[0018] The present invention also aims to advantageously solve the above-mentioned problems, and the method for manufacturing a thermoelectric conversion element of the present invention is a method for manufacturing any of the thermoelectric conversion elements of the present invention described above, characterized in that it includes a step of forming slits in a long thermoelectric conversion raw material structure. By forming slits in the long thermoelectric conversion raw structure in this way, the above-mentioned thermoelectric conversion element including a thermoelectric conversion structure having slits can be easily obtained.

[0019] Here, in the method for producing a thermoelectric conversion element of the present invention, the width dimensions of the thermoelectric conversion element at both sides of the slit in the width direction are all the same, and the width dimensions satisfy the following relational expressions (1) and (2′): S < W / n (1) R' < Rn / n (2)' [In formula (1), n ​​is the number of slits, S is the total width of the slits, and W is the width of the thermoelectric conversion element.] In formula (2)', n is the number of slits, R' is the electrical resistance of the thermoelectric conversion raw material structure, and Rn is the electrical resistance of the portions of the thermoelectric conversion element located on both sides of the slit in the width direction. It is preferable to satisfy the following. If the width dimensions of the portions located on both sides of the slit in the width direction are all made the same and the relational expressions (1) and (2)' are satisfied, the electrical resistance of the thermoelectric conversion element can be further reduced.

[0020] The present invention also aims to advantageously solve the above-mentioned problems, and the method for manufacturing a thermoelectric conversion module of the present invention is a method for manufacturing any of the above-mentioned thermoelectric conversion modules (series-connected thermoelectric conversion modules) of the present invention, characterized in that it includes a step of forming slits in a long thermoelectric conversion raw structure to manufacture thermoelectric conversion elements (a1) or thermoelectric conversion elements (a2), and / or a step of cutting the long thermoelectric conversion raw structure in the longitudinal direction to manufacture thermoelectric conversion elements (a3). In this way, by forming slits in the long thermoelectric conversion raw structure or cutting the long thermoelectric conversion raw structure in the longitudinal direction, the above-mentioned thermoelectric conversion module including the thermoelectric conversion element (A) can be easily obtained.

[0021] In the method for producing a thermoelectric conversion module of the present invention, the thermoelectric conversion elements (a1) and (a2) have the same width dimension at portions located on both sides of the slit in the width direction, the thermoelectric conversion elements (a3) ​​have the same width dimension at portions located on both sides of the slit in the width direction, and the thermoelectric conversion elements (A) have a plurality of elongated thermoelectric conversion structures arranged in parallel, and the thermoelectric conversion elements (A) satisfy the following relational expressions (1) and (2'): S < W / n (1) R' < Rn / n (2)' [In formula (1), n ​​is the number of slits or gaps, S is the total width of the slits or gaps, and W is the width of the thermoelectric conversion element (A). In formula (2)', n is the number of slits or gaps, R' is the electrical resistance of the thermoelectric conversion raw structure, and Rn is the electrical resistance of the portions located on both sides of the slit in the width direction when the thermoelectric conversion element (A) is the thermoelectric conversion element (a1) or the thermoelectric conversion element (a2), and is the electrical resistance of the long thermoelectric conversion structure when the thermoelectric conversion element (A) is the thermoelectric conversion element (a3). It is preferable to satisfy the following formula: If the width dimensions of the portions located on both sides of the slit in the width direction or the width dimensions of the plurality of elongated thermoelectric conversion structures arranged in parallel are all made the same and the formulas (1) and (2)' are satisfied, the electrical resistance of the thermoelectric conversion element can be further reduced and the power generation efficiency of the obtained thermoelectric conversion module can be further increased.

[0022] The present invention also aims to advantageously solve the above-mentioned problems, and the method for manufacturing a thermoelectric conversion module of the present invention is a method for manufacturing the above-mentioned thermoelectric conversion module (parallel-connected thermoelectric conversion module) of the present invention, characterized in that it includes a step of producing a thermoelectric conversion element using any of the above-mentioned methods for manufacturing a thermoelectric conversion element of the present invention. In this way, by using the method for manufacturing a thermoelectric conversion element of the present invention described above, the above-mentioned thermoelectric conversion module can be easily obtained. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a thermoelectric conversion element having a lower electrical resistance. Furthermore, according to the present invention, it is possible to provide a thermoelectric conversion module with excellent power generation efficiency. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is an explanatory diagram showing a schematic configuration of an example of a series-connected thermoelectric conversion module of the present invention. [Figure 2] FIG. 1(a) is a plan view of an example of a thermoelectric conversion element (a1), and FIG. 1(b) is a plan view of another example of a thermoelectric conversion element (a1). [Figure 3] 1(a) is a plan view of an example of a thermoelectric conversion element (a2), and FIG. 1(b) is a plan view of another example of a thermoelectric conversion element (a2). [Figure 4] FIG. 1 is a plan view of an example of a thermoelectric conversion element (a3). [Figure 5] FIG. 10 is an explanatory diagram showing a schematic configuration of another example of a series-connected thermoelectric conversion module of the present invention. [Figure 6]FIG. 6 is an enlarged view showing the area surrounded by the dashed line in FIG. 5. [Figure 7] 1 is an explanatory diagram showing a schematic configuration of an example of a parallel-connection type thermoelectric conversion module of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or similar components are denoted by the same reference numerals, and in each drawing, the dimensions of some components are enlarged or reduced to facilitate understanding.

[0026] The thermoelectric conversion module of the present invention includes a plurality of thermoelectric conversion elements that convert heat into electric power by utilizing the temperature difference between both ends, and is used, for example, by being disposed between a high-temperature part and a low-temperature part when generating electric power. The thermoelectric conversion elements of the thermoelectric conversion module of the present invention are not particularly limited, and the thermoelectric conversion elements of the present invention can be used.

[0027] Below, the thermoelectric conversion module of the present invention will be described separately as a series-connected thermoelectric conversion module in which multiple thermoelectric conversion elements are electrically connected in series, and a parallel-connected thermoelectric conversion module in which multiple thermoelectric conversion elements are electrically connected in parallel. The following description will be given using an example of a thermoelectric conversion module in which thermoelectric conversion elements are arranged on one surface of a sheet substrate and wiring connecting the thermoelectric conversion elements is arranged on the other surface of the sheet substrate. However, the present invention is not limited to this configuration. Specifically, thermoelectric conversion elements may be arranged on both sides of the sheet substrate, and wiring may be arranged within the sheet substrate. Furthermore, the base material on which the thermoelectric conversion elements are arranged is not limited to a sheet substrate. Furthermore, the element configuration of the thermoelectric conversion elements is not particularly limited. The thermoelectric conversion elements may all be p-type, all n-type, or may be composed of p-type and n-type. When the thermoelectric conversion material used to form the thermoelectric conversion elements is an organic material such as carbon nanotubes, oxidation of the thermoelectric conversion material due to oxygen and moisture in the atmosphere can be a major cause of performance degradation of the thermoelectric conversion elements. In this case, n-type thermoelectric conversion elements are more susceptible to oxidation due to oxygen and moisture in the atmosphere than p-type thermoelectric conversion elements. Therefore, from the perspective of durability of the thermoelectric conversion module, it is preferable to use only p-type thermoelectric conversion elements.

[0028] (Series-connected thermoelectric conversion module) The series-connected thermoelectric conversion module of the present invention includes a plurality of elongated thermoelectric conversion elements electrically connected in series via their longitudinal ends. In the series-connected thermoelectric conversion module of the present invention, the plurality of thermoelectric conversion elements electrically connected in series are (1) A thermoelectric conversion element (a1) comprising a long thermoelectric conversion structure having at least one slit formed therein, the slit extending in the longitudinal direction and having both ends terminated within the thermoelectric conversion structure; (2) A thermoelectric conversion element (a2) including a long thermoelectric conversion structure having at least one slit extending in the longitudinal direction, one end of which terminates within the thermoelectric conversion structure and the other end of which is open, and a junction that electrically connects the end of the thermoelectric conversion structure on the side where the slit is open across the opening of the slit, and (3) A thermoelectric conversion element (a3) ​​comprising: a plurality of elongated thermoelectric conversion structures arranged in parallel with gaps in a direction perpendicular to the longitudinal direction; a first junction electrically connecting the ends of the thermoelectric conversion structures on one end in the longitudinal direction; and a second junction electrically connecting the ends of the thermoelectric conversion structures on the other end in the longitudinal direction. The thermoelectric conversion element (A) contains at least one type of thermoelectric conversion element (A) selected from the group consisting of:

[0029] In this way, by including at least one thermoelectric conversion element (A) selected from the group consisting of thermoelectric conversion elements (a1) to (a3) ​​as the thermoelectric conversion elements electrically connected in series, the electrical resistance of the series-connected thermoelectric conversion module can be reduced and power generation efficiency can be increased. As the thermoelectric conversion element, the thermoelectric conversion element (A) may be used in combination with any thermoelectric conversion element other than the thermoelectric conversion element (A). However, from the viewpoint of reducing the electrical resistance of the series-connected thermoelectric conversion module and improving the power generation efficiency, it is preferable that all of the thermoelectric conversion elements electrically connected in series are thermoelectric conversion elements (A).

[0030] Specifically, an example of a series-connected thermoelectric conversion module of the present invention can be used by being disposed between a high-temperature side (upper side in FIG. 1 ) where a heat source is located and a low-temperature side (lower side in FIG. 1 ) away from the heat source, as shown in the schematic configuration of a plan view in FIG. 1 . The series-connected thermoelectric conversion module 100 shown in FIG. 1 includes a sheet substrate 1, a plurality of (four in the illustrated example) thermoelectric conversion elements 2 provided on one surface of the sheet substrate 1, electrodes 4 electrically connected via bonding members 3 to both ends of the elongated thermoelectric conversion elements 2 in the longitudinal direction (vertical direction in FIG. 1 ), and wiring 5 provided on the other surface of the sheet substrate 1, electrically connecting adjacent thermoelectric conversion elements 2 in series via the electrodes 4. The wiring 5 electrically connects the electrode 4 located at one end of one thermoelectric conversion element 2 in the longitudinal direction (upper side in FIG. 1 ) to the electrode 4 located at the other end of the other thermoelectric conversion element 2 in the longitudinal direction (lower side in FIG. 1 ). In the series-connected thermoelectric conversion module 100, the joining members 3 and electrodes 4 are provided at both longitudinal ends of the thermoelectric conversion elements 2. However, in the series-connected thermoelectric conversion module of the present invention, the joining members 3 and / or electrodes 4 may not be provided as long as the thermoelectric conversion elements 2 can be electrically connected in series. In the series-connected thermoelectric conversion module 100, all of the thermoelectric conversion elements 2 are arranged so that their positions in the vertical direction in FIG. 1 are the same (in other words, for all of the thermoelectric conversion elements 2, one longitudinal edge is located on the same imaginary line extending along the left-right direction in FIG. 1, and the other longitudinal edge is also located on the same imaginary line extending along the left-right direction in FIG. 1). However, the thermoelectric conversion elements 2 can be arranged at any position. Furthermore, the arrangement intervals of the thermoelectric conversion elements 2 may be arbitrary as long as insulation between two adjacent thermoelectric conversion elements 2 is ensured.

[0031] The sheet substrate 1 is an insulating substrate, and is rectangular in plan view in the example shown in Fig. 1. The sheet substrate 1 may also be flexible. The material for forming the sheet substrate 1 is not particularly limited, and any insulating material can be used.

[0032] The sheet substrate 1 may have a multilayer structure. Specifically, the sheet substrate 1 may include an insulating, optionally flexible, substrate and an insulating layer disposed on the side of the substrate where the thermoelectric conversion elements 2 are disposed. The material for forming the substrate is not particularly limited, and any material such as polyimide or epoxy glass can be used. The material for forming the insulating layer is not particularly limited, and any insulating material can be used.

[0033] The thermoelectric conversion elements 2 are elongated thermoelectric conversion elements whose longitudinal dimension is greater than their width dimension (left-right direction in FIG. 1). All of the thermoelectric conversion elements 2 of the series-connected thermoelectric conversion module 100 shown in FIG. 1 are thermoelectric conversion elements (a1) made of elongated thermoelectric conversion structures each having at least one slit extending in the longitudinal direction and terminating at both ends within the thermoelectric conversion structure.

[0034] Specifically, the thermoelectric conversion element 2 has a planar shape as shown in Figure 2(a), in which the dimension D in the longitudinal direction (the vertical direction in Figure 2) is greater than the dimension W in the width direction (the horizontal direction in Figure 2), and is made up of a long thermoelectric conversion structure 20 in which at least one slit 21 (three in the illustrated example) is formed, extending in the longitudinal direction and having both ends 21a, 21b terminating within the thermoelectric conversion structure 20.

[0035] Here, any structure formed of a thermoelectric conversion material, such as a thin film made of a thermoelectric conversion material, can be used as the thermoelectric conversion structure 20. The thermoelectric conversion material for forming the thermoelectric conversion structure 20 is not particularly limited, and examples that can be used include bismuth tellurium-based compounds, antimony-based compounds, silicon-based compounds, metal oxide-based compounds, Heusler alloy-based compounds, conductive polymer compounds, conductive fibers, and composite materials thereof.

[0036] Among these, a structure in which a conductive material is arranged in a non-oriented state is preferred as the thermoelectric conversion structure 20, a structure in which a conductive fibrous carbon material such as carbon nanotubes (hereinafter also referred to as "CNTs") is arranged in a non-oriented state is more preferred, and a CNT film is even more preferred. This is because a thermoelectric conversion structure 20 in which a conductive material is arranged in a non-oriented state has a reduced electrical resistance compared to a thermoelectric conversion structure that has the same shape, dimensions, and material but does not have slits, presumably because a conductive path is formed along the edge extending in the longitudinal direction of the slits 21. Furthermore, the use of CNTs can improve the mechanical strength of the series-connected thermoelectric conversion module 100 and reduce its weight. The CNTs are not particularly limited, and single-walled CNTs and / or multi-walled CNTs can be used, but the CNTs are preferably single-walled CNTs, because single-walled CNTs have superior thermoelectric properties (Seebeck coefficient).

[0037] As shown in Figure 2(a), the slit 21 has a rectangular shape in a plan view with a width dimension S, and one longitudinal edge 21a (upper side in Figure 2(a)) and the other longitudinal edge 21b (lower side in Figure 2(a)) terminate within the thermoelectric conversion structure 20 without opening to the edges 2a, 2b located on both sides of the thermoelectric conversion structure 20 in the longitudinal direction.

[0038] Therefore, the thermoelectric conversion structure 20 has a shape including a plurality of (four in the illustrated example) narrow portions 22 extending in the longitudinal direction and having a width dimension narrower than that of the wide portions 23a, 23b, between which are wide portions 23a, 23b located at both ends in the longitudinal direction and having the same width dimension W as the thermoelectric conversion element 2.

[0039] The thermoelectric conversion element 2 made of the thermoelectric conversion structure 20 has reduced electrical resistance compared to a thermoelectric conversion element made of a thermoelectric conversion structure that has the same shape, dimensions, and material but does not have slits, presumably due to the presence of multiple narrow portions 22 within the element. Therefore, the series-connected thermoelectric conversion module 100 including the thermoelectric conversion element 2 can exhibit excellent power generation efficiency. In the thermoelectric conversion element 2, the slits 21 are preferably formed so that the longitudinal positions of the edges 21a and 21b are the same (in other words, for all slits 21, one longitudinal edge 21a is located on the same imaginary line extending along the width direction of the thermoelectric conversion element 2, and the other longitudinal edge 21b is also located on the same imaginary line extending along the width direction of the thermoelectric conversion element 2), but the slits 21 can be positioned at any position within the thermoelectric conversion structure 20.

[0040] The joining members 3 that electrically connect the longitudinal ends of the thermoelectric conversion elements 2 to the electrodes 4 are not particularly limited, and any conductive member such as solder or silver paste can be used.

[0041] The electrodes 4 and the wiring 5 may be made of the same conductive material or different conductive materials. The conductive material is not particularly limited, and any metal such as copper or aluminum can be used. The electrodes 4 are not particularly limited, but may have a configuration in which one surface is exposed on the surface of the sheet substrate 1 on which the thermoelectric conversion elements 2 are arranged, and the other surface is connected to wiring 5 on the other surface side of the sheet substrate 1. Any of the plurality of electrodes 4 may be electrically connected to extraction wiring for extracting the power generated by the series-connected thermoelectric conversion module 100.

[0042] In the series-connected thermoelectric conversion module 100, the temperature of the end portion (the end portion on the high temperature side) located on one side in the longitudinal direction of each thermoelectric conversion element 2 becomes higher than the temperature of the end portion (the end portion on the low temperature side) located on the other side in the longitudinal direction, generating a temperature gradient within the thermoelectric conversion element 2. As a result, an electromotive force is generated in the thermoelectric conversion element 2 due to the Seebeck effect caused by the temperature gradient, and the series-connected thermoelectric conversion module 100 can generate electricity. In this case, since the series-connected thermoelectric conversion module 100 uses thermoelectric conversion elements 2 with low electrical resistance, power generation efficiency can be improved.

[0043] In the above example, a case has been described in which a thermoelectric conversion element (a1) having a structure as shown in FIG. 2(a) is used as the thermoelectric conversion element (A) included in the series-connected thermoelectric conversion module, but the thermoelectric conversion element (A) used in the series-connected thermoelectric conversion module of the present invention is not limited to the structure shown in FIG. 2(a).

[0044] Specifically, a thermoelectric conversion element (a1) having a structure as shown in Fig. 2(b) may be used as the thermoelectric conversion element (A). Here, the thermoelectric conversion element 2A shown in Fig. 2(b) has the same configuration as the thermoelectric conversion element 2 shown in Fig. 2(a), except that the slits 21 extending in the longitudinal direction and terminating at both ends 21a, 21b within the thermoelectric conversion structure 20 have an elliptical shape in a plan view. Even the thermoelectric conversion element 2A having such a structure has a plurality of narrow portions 22 within the element, and therefore, the electrical resistance can be reduced compared to a thermoelectric conversion element made of a thermoelectric conversion structure that has the same shape, dimensions, and material except for not having slits.

[0045] In the present invention, the planar shape of the slits of the thermoelectric conversion element (a1) is not limited to a rectangular or elliptical shape, but may be any shape. Furthermore, the extending direction of the slits of the thermoelectric conversion element (a1) is not limited to a direction parallel to the longitudinal direction of the thermoelectric conversion element (a1), but may be inclined relative to the longitudinal direction as long as they do not open to the side edges of the thermoelectric conversion element (a1). The slits can be designed to optimize the actual resistance value and for process convenience, such as making the slits smaller at the connection portions with electrodes to facilitate connection.

[0046] As the thermoelectric conversion element (A), for example, a thermoelectric conversion element (a2) having a structure as shown in FIGS. 3(a) and 3(b) may be used.

[0047] Here, the thermoelectric conversion element 2B shown in Figure 3(a) has a configuration similar to that of the thermoelectric conversion element 2 shown in Figure 2(a), except that the slit 21 extends in the longitudinal direction, with one end 21a terminating within the thermoelectric conversion structure 20 and the other end 21b opening at the edge 2b on the other side of the longitudinal direction of the thermoelectric conversion structure 20 (the lower side in Figure 3(a)), does not have a wide portion 23b at the other end of the longitudinal direction, and has a junction 24 that electrically connects the other end of the longitudinal direction across the opening of the slit 21.

[0048] The joint 24 electrically connects the other longitudinal end of the thermoelectric conversion structure 20, specifically the other longitudinal end of the plurality of (four in the illustrated example) narrow width portions 22 positioned in parallel with the opening in between. The joint 24 is not particularly limited, and any conductive material such as solder or silver paste can be used. In the series-connected thermoelectric conversion module, the joints may function as joining members that electrically connect the longitudinal ends of the thermoelectric conversion elements to the electrodes.

[0049] The thermoelectric conversion element 2B has a reduced electrical resistance compared to a thermoelectric conversion element having a thermoelectric conversion structure that has the same shape, dimensions, and material but does not have slits, presumably due to the presence of multiple narrow portions 22 within the element. Therefore, a series-connected thermoelectric conversion module including the thermoelectric conversion element 2B can exhibit excellent power generation efficiency. In the thermoelectric conversion element 2B, the slits 21 are preferably formed so that the longitudinal positions of the edge 21a are the same (in other words, for all slits 21, one longitudinal edge 21a is positioned on the same imaginary line extending along the width direction of the thermoelectric conversion element 2), but the slits 21 can be positioned at any position within the thermoelectric conversion structure 20.

[0050] 3(b) has a similar configuration to the thermoelectric conversion element 2B shown in Fig. 3(a) except that the slits 21 have a substantially elliptical shape in a plan view (specifically, a shape in which one end in the major axis direction is cut and removed in a direction perpendicular to the major axis), the slits 21 extending in the longitudinal direction have one end 21a terminating within the thermoelectric conversion structure 20 and the other end 21b opening at the edge 2b in the other longitudinal direction (the lower side in Fig. 3(b)) of the thermoelectric conversion structure 20. Even the thermoelectric conversion element 2C having such a structure has a plurality of narrow portions 22 within the element, and therefore the electrical resistance can be reduced compared to a thermoelectric conversion element made of a thermoelectric conversion structure that has the same shape, dimensions, and material except for not having slits.

[0051] In the present invention, the planar shape of the slits of the thermoelectric conversion element (a2) is not limited to the shapes shown in Figures 3(a) and (b) and can be any shape. Furthermore, the extension direction of the slits of the thermoelectric conversion element (a2) is not limited to a direction parallel to the longitudinal direction of the thermoelectric conversion element (a2). The slits may be inclined relative to the longitudinal direction as long as one longitudinal end does not open to the side edge of the thermoelectric conversion element (a2). The slits can be designed to optimize the actual resistance value and for process convenience, such as making the slits smaller at the connection portion with the electrodes to facilitate connection.

[0052] Furthermore, as the thermoelectric conversion element (A), for example, a thermoelectric conversion element (a3) ​​having a structure as shown in FIG. 4 may be used.

[0053] Here, the thermoelectric conversion element 2D shown in Figure 4 includes a plurality of elongated thermoelectric conversion structures 20 (two in the illustrated example) arranged in parallel with a gap 25 of width dimension S in a direction (left-right direction in Figure 4) perpendicular to the longitudinal direction (up-down direction in Figure 4), a first junction 24a that electrically connects the end portions 20a at one longitudinal end side (upper side in Figure 4) of the thermoelectric conversion structures 20, and a second junction 24b that electrically connects the end portions 20b at the other longitudinal end side (lower side in Figure 4) of the thermoelectric conversion structures 20.

[0054] The joints 24a and 24b electrically connect the longitudinal ends of a plurality of (two in the illustrated example) thermoelectric conversion structures 20 positioned in parallel across a gap 25, across the gap 25. The joints 24a and 24b are not particularly limited, and any conductive material such as solder or silver paste can be used. In the series-connected thermoelectric conversion module, the joints may function as joining members that electrically connect the longitudinal ends of the thermoelectric conversion elements to the electrodes.

[0055] The thermoelectric conversion element 2D has a reduced electrical resistance compared to a thermoelectric conversion element having the same shape, dimensions, and material (in other words, a thermoelectric conversion element made of thermoelectric conversion structures 20 with a width of W) except for not having gaps 25, which is presumably due to the presence of multiple narrow conductive paths (multiple thermoelectric conversion structures 20 with ends electrically connected to each other) within the element. Therefore, a series-connected thermoelectric conversion module including the thermoelectric conversion element 2D can exhibit excellent power generation efficiency. In the thermoelectric conversion element 2D, the thermoelectric conversion structures 20 are preferably arranged so that the longitudinal positions of the end edges 20a, 20b are the same (in other words, for all the thermoelectric conversion structures 20, one longitudinal edge 20a is located on the same imaginary line extending along the width direction of the thermoelectric conversion element 2D, and the other longitudinal edge 20b is also located on the same imaginary line extending along the width direction of the thermoelectric conversion element 2D), but the thermoelectric conversion structures 20 can also be arranged with their longitudinal positions shifted.

[0056] In the present invention, the planar shape of the thermoelectric conversion structure and gaps of the thermoelectric conversion element (a3) ​​is not limited to the shape (rectangular) shown in FIG. 4 and can be any shape. Furthermore, the extension direction of the gaps of the thermoelectric conversion element (a3) ​​is not limited to a direction parallel to the longitudinal direction of the thermoelectric conversion element (a3) ​​and may be a direction inclined relative to the longitudinal direction. Although the multiple thermoelectric conversion structures included in the thermoelectric conversion element (a3) ​​may be made of different materials, it is preferable that they be made of the same material. Furthermore, although the multiple thermoelectric conversion structures included in the thermoelectric conversion element (a3) ​​may have different shapes, it is preferable that they have the same shape.

[0057] The above-mentioned thermoelectric conversion elements (a1) to (a3) ​​preferably have the following configurations.

[0058] Specifically, when the thermoelectric conversion element (a1) and the thermoelectric conversion element (a2) have two or more slits, it is preferable that the shapes of the slits are all the same from the viewpoint of improving the uniformity of the thermoelectric conversion elements and facilitating manufacturing. Furthermore, when the thermoelectric conversion element (a3) ​​has two or more gaps, it is preferable that the shapes of all the gaps are the same, from the viewpoint of improving the uniformity of the thermoelectric conversion element and facilitating production.

[0059] Furthermore, the thermoelectric conversion elements (a1) to (a3) ​​satisfy the following relational formula (1): S < W / n (1) It is preferable to satisfy the following. Here, for the thermoelectric conversion elements (a1) and (a2), in formula (1), n ​​is the number of slits, S is the total width of the slits, and W is the width of the thermoelectric conversion element. Also, for the thermoelectric conversion element (a3), in formula (1), n ​​is the number of gaps, S is the total width of the gaps, and W is the width of the thermoelectric conversion element. The relational expression (1) is an index that determines the processability of the slits and gaps, and W or n can be set according to the width of the slits or gaps that can be formed in the patterning process actually performed when fabricating the thermoelectric conversion elements (a1) to (a3).

[0060] In addition, from the viewpoint of further reducing the electrical resistance of the series-connected thermoelectric conversion module, it is preferable that the thermoelectric conversion elements (a1) and (a2) have the same width dimension at the portions (narrow portions) located on both sides of the slit in the width direction, and satisfy the above-mentioned relational formula (1) and the following relational formula (2), and it is preferable that the thermoelectric conversion elements (a3) ​​have the same width dimension at the plurality of elongated thermoelectric conversion structures arranged in parallel, and satisfy the above-mentioned relational formula (1) and the following relational formula (2). R < Rn / n (2) Here, for thermoelectric conversion elements (a1) and (a2), in formula (2), n is the number of slits, R is the electrical resistance of a hypothetical thermoelectric conversion element consisting of a long thermoelectric conversion structure having the same width, length, and thickness as thermoelectric conversion elements (a1) and (a2) and no slits, and Rn is the electrical resistance of the portions (narrow portions) located on both sides of the slits in the width direction. Also, for thermoelectric conversion element (a3), in formula (2), n is the number of gaps, R is the electrical resistance of a hypothetical thermoelectric conversion element consisting of a long thermoelectric conversion structure having the same width, length, and thickness as thermoelectric conversion element (a3) ​​and no gaps, and Rn is the electrical resistance of the long thermoelectric conversion structure.

[0061] The above describes the series-connected thermoelectric conversion module of the present invention and the thermoelectric conversion element used in the series-connected thermoelectric conversion module using the series-connected thermoelectric conversion module 100 as an example, but the series-connected thermoelectric conversion module and thermoelectric conversion element of the present invention are not limited to the above.

[0062] For example, the series-connected thermoelectric conversion module of the present invention can have a shape as shown in the plan view in Figure 5 (sometimes called a "fan shape," in which both ends of two circular arcs with different radii are connected in the radial direction).

[0063] 5 is not particularly limited, and can be used, for example, by placing it around a pipe through which a high-temperature fluid flows and utilizing the temperature difference between the outside air and the pipe to generate power. The fan-shaped thermoelectric conversion module can be installed to fit the shape of the pipe, making the temperature difference more uniform and ultimately improving power generation efficiency.

[0064] The series-connected thermoelectric conversion module 200 is formed by connecting in series thermoelectric conversion elements 2E each having a slit 21 that terminates within a thermoelectric conversion structure 20 having an approximately trapezoidal shape at both ends, as shown in Figure 6, which is an enlarged view of the area surrounded by the dashed line in Figure 5.

[0065] (Parallel-connected thermoelectric conversion module) The parallel-connection type thermoelectric conversion module of the present invention includes a plurality of elongated thermoelectric conversion elements electrically connected in parallel via their longitudinal ends. In the parallel-connection type thermoelectric conversion module of the present invention, the plurality of thermoelectric conversion elements electrically connected in parallel are (1) A thermoelectric conversion element (a1) comprising an elongated thermoelectric conversion structure having at least one slit formed therein, the slit extending in the longitudinal direction and having both ends terminated within the thermoelectric conversion structure; and (2) A thermoelectric conversion element (a2) comprising: a long thermoelectric conversion structure having at least one slit extending in the longitudinal direction, one end of which terminates within the thermoelectric conversion structure and the other end of which is open; and a junction that electrically connects the end of the thermoelectric conversion structure on the side where the slit is open, across the opening of the slit; It contains at least one of the following.

[0066] In this way, by including at least one type of thermoelectric conversion element selected from the group consisting of the thermoelectric conversion element (a1) and the thermoelectric conversion element (a2) as the thermoelectric conversion elements electrically connected in parallel, the electrical resistance of the parallel-connected thermoelectric conversion module can be reduced and the power generation efficiency can be increased. As the thermoelectric conversion element, the thermoelectric conversion element (a1) and / or the thermoelectric conversion element (a2) may be used in combination with any thermoelectric conversion element other than the thermoelectric conversion element (a1) and the thermoelectric conversion element (a2). However, from the viewpoint of reducing the electrical resistance of the parallel-connected thermoelectric conversion module and improving the power generation efficiency, it is preferable that all of the thermoelectric conversion elements electrically connected in parallel are the thermoelectric conversion elements (a1) and / or the thermoelectric conversion elements (a2).

[0067] Specifically, an example of a parallel-connection type thermoelectric conversion module of the present invention can be used by being disposed between a high-temperature side (upper side in FIG. 7 ) where a heat source is located and a low-temperature side (lower side in FIG. 7 ) away from the heat source, as shown in the schematic configuration of a plan view in FIG. 7 . The parallel-connection type thermoelectric conversion module 300 shown in FIG. 7 includes a sheet substrate 1, a plurality of (four in the illustrated example) thermoelectric conversion elements 2 provided on one surface of the sheet substrate 1, bonding members 3 provided at both ends of the elongated thermoelectric conversion elements 2 in the longitudinal direction (the vertical direction in FIG. 1 ), and electrodes 4 electrically connected to the thermoelectric conversion elements 2 via the bonding members 3 and electrically connecting all of the thermoelectric conversion elements 2 in parallel. Here, the electrodes 4 provided at one end and the other end of the thermoelectric conversion elements 2 in the longitudinal direction extend in the left-right direction in FIG. 7 and are electrically connected to the bonding members 3. In the parallel-connection type thermoelectric conversion module 300, the joining members 3 are provided at both longitudinal ends of the thermoelectric conversion elements 2. However, in the parallel-connection type thermoelectric conversion module of the present invention, the joining members 3 may not be provided as long as the thermoelectric conversion elements 2 can be electrically connected in parallel. In the parallel-connection type thermoelectric conversion module 300, the thermoelectric conversion elements 2 are electrically connected in parallel using the electrodes 4. However, in the parallel-connection type thermoelectric conversion module of the present invention, the thermoelectric conversion elements may be electrically connected in parallel using means other than electrodes, such as wiring. Furthermore, in the parallel-connection type thermoelectric conversion module 300, all of the thermoelectric conversion elements 2 are arranged so that their positions in the vertical direction in FIG. 7 are the same (in other words, for all of the thermoelectric conversion elements 2, one longitudinal end edge is located on the same imaginary line extending along the left-right direction in FIG. 7, and the other longitudinal end edge is also located on the same imaginary line extending along the left-right direction in FIG. 7). However, the thermoelectric conversion elements 2 may be arranged in any position. The thermoelectric conversion elements 2 may be arranged at any interval as long as insulation between two adjacent thermoelectric conversion elements 2 can be ensured.

[0068] Here, the sheet substrate 1, bonding members 3, and electrodes 4 of the parallel connection type thermoelectric conversion module 300 can be the same as those of the above-mentioned series connection type thermoelectric conversion module 100, and therefore, description thereof will be omitted below.

[0069] Moreover, the thermoelectric conversion elements 2 of the parallel connection type thermoelectric conversion module 300 have the same configuration as the thermoelectric conversion elements 2 used in the series connection type thermoelectric conversion module 100 described above.

[0070] In the parallel-connection type thermoelectric conversion module 300, the temperature of the end portion (the end portion on the high temperature side) located on one side in the longitudinal direction of each thermoelectric conversion element 2 becomes higher than the temperature of the end portion (the end portion on the low temperature side) located on the other side in the longitudinal direction, and a temperature gradient occurs within the thermoelectric conversion element 2. As a result, an electromotive force is generated in the thermoelectric conversion element 2 due to the Seebeck effect caused by the temperature gradient, and the parallel-connection type thermoelectric conversion module 300 can generate electricity. In this case, since the parallel-connection type thermoelectric conversion module 300 uses thermoelectric conversion elements 2 with low electrical resistance, power generation efficiency can be improved.

[0071] In the above example, the thermoelectric conversion element 2 having the structure shown in Fig. 2(a) is used as the thermoelectric conversion element included in the parallel-connection type thermoelectric conversion module, but the thermoelectric conversion elements that can be used in the parallel-connection type thermoelectric conversion module of the present invention are not limited to the structure shown in Fig. 2(a). Specifically, the thermoelectric conversion elements that can be used are the same as those described above as the thermoelectric conversion elements (a1) and thermoelectric conversion elements (a2) that can be used in the series-connection type thermoelectric conversion module, and the preferred forms thereof are also as described above.

[0072] The above describes the parallel-connection type thermoelectric conversion module of the present invention and the thermoelectric conversion element used in the parallel-connection type thermoelectric conversion module using the parallel-connection type thermoelectric conversion module 300 as an example, but the parallel-connection type thermoelectric conversion module and thermoelectric conversion element of the present invention are not limited to the above.

[0073] (Method of manufacturing thermoelectric conversion module) The method for manufacturing a thermoelectric conversion module of the present invention can be used to manufacture the above-mentioned series-connected thermoelectric conversion module and parallel-connected thermoelectric conversion module. The method for manufacturing a thermoelectric conversion module of the present invention includes a step of processing a long thermoelectric conversion raw structure to manufacture a thermoelectric conversion element (element manufacturing step), and may optionally further include at least one step selected from the group consisting of a step of forming wiring (wiring forming step), a step of manufacturing electrodes (electrode manufacturing step), and a step of forming bonding members (bonding member forming step). These steps can be performed in any order, but the bonding member forming step is usually performed after the element fabricating step and the electrode fabricating step.

[0074] <Wiring formation process> In the wiring formation step, wiring is formed on a member on which wiring is to be formed, such as a sheet substrate.

[0075] Here, the method for forming the wiring is not particularly limited, and any method that can be used for manufacturing a thermoelectric conversion module can be used. Specifically, the wiring can be formed, for example, by placing a metal foil on the surface of a base material such as a sheet substrate on which the wiring is to be formed, using an adhesive or the like, and patterning the metal foil using a method such as photolithography. When wiring is formed inside a member such as a sheet substrate on which a thermoelectric conversion element is disposed, for example, wiring may be formed on the surface of a base material, and then an insulating layer may be formed on the surface of the base material on which the wiring is formed. Here, the insulating layer may be formed using a known method such as coating an insulating material.

[0076] <Electrode manufacturing process> In the electrode fabrication step, electrodes are formed on a member on which electrodes are to be formed, such as a sheet substrate, by any method that can be used in manufacturing a thermoelectric conversion module.

[0077] Here, without any particular limitation, the electrodes can be produced simultaneously with the formation of the wiring. Specifically, for example, when patterning a metal foil to form wiring, the electrodes can be formed by simultaneously patterning the portions that will become the electrodes. In addition, if the location where the wiring is formed is inside the component on which the thermoelectric conversion element is placed or on the opposite side to the side on which the thermoelectric conversion element is placed, the electrodes can be exposed on the side on which the thermoelectric conversion element is placed using known methods such as forming an insulating layer so that the electrodes are exposed, or forming holes in the component on which the thermoelectric conversion element is placed, such as a sheet substrate.

[0078] <Element manufacturing process> In the element preparation step, a long thermoelectric conversion raw structure arranged on a member for arranging thermoelectric conversion elements, such as a sheet substrate, is processed to prepare a thermoelectric conversion element. Specifically, when a series-connected thermoelectric conversion module is produced, the element preparation step processes the thermoelectric conversion raw structure to prepare at least one thermoelectric conversion element (A) selected from the group consisting of thermoelectric conversion elements (a1) to (a3). In addition, when a parallel-connected thermoelectric conversion module is produced, the element preparation step processes the thermoelectric conversion raw structure to prepare at least one thermoelectric conversion element selected from the group consisting of thermoelectric conversion elements (a1) and (a2).

[0079] Here, the thermoelectric conversion raw structure is processed to become the thermoelectric conversion structure of the thermoelectric conversion element described above. Any structure formed of a thermoelectric conversion material, such as a thin film made of a thermoelectric conversion material, can be used as the thermoelectric conversion raw structure. The thermoelectric conversion material used to form the thermoelectric conversion raw structure can be the same as that described above for the thermoelectric conversion structure of the thermoelectric conversion element.

[0080] The arrangement of the thermoelectric conversion raw material structure on a member such as a sheet substrate is not particularly limited, and can be carried out by a method of attaching a previously prepared thermoelectric conversion raw material structure to the member using an adhesive or the like, or by a method of applying a composition containing a thermoelectric conversion raw material, such as a carbon nanotube dispersion liquid, to a member such as a sheet substrate and drying or curing it as necessary.

[0081] Furthermore, the method for processing the thermoelectric conversion raw structure is not particularly limited as long as it can process the thermoelectric conversion raw structure into a desired shape, and examples thereof include processing methods using lasers such as fiber lasers, YAG (Yttrium Aluminum Garnet) lasers, UV (Ultra Violet) lasers, nanosecond lasers, and femtosecond lasers, and processing methods using cutting blades such as utility knives.

[0082] The thermoelectric conversion elements (a1) and (a2) can be produced by forming slits of desired shapes in the long thermoelectric conversion raw structure. The thermoelectric conversion element (a3) ​​can be produced by cutting a long thermoelectric conversion raw structure in the longitudinal direction at a desired position. The joining portion of the thermoelectric conversion elements (a2) and (a3) ​​can be formed using any conductive material such as solder or silver paste, and may be performed simultaneously with the joining member forming step described below.

[0083] In the production of the thermoelectric conversion elements (a1) to (a3), the thermoelectric conversion elements to be obtained satisfy the following relational formula (1): S < W / n (1) It is preferable to satisfy the following. Here, for the thermoelectric conversion elements (a1) and (a2), in formula (1), n ​​is the number of slits, S is the total width of the slits, and W is the width of the thermoelectric conversion element. Also, for the thermoelectric conversion element (a3), in formula (1), n ​​is the number of gaps, S is the total width of the gaps, and W is the width of the thermoelectric conversion element.

[0084] In the production of the thermoelectric conversion elements (a1) and (a2), it is preferable to form the slits so that the widths of the portions (narrow portions) located on both sides of the slit in the width direction are all the same, and further, the following relational expression (2'): R' < Rn / n (2)' Here, in formula (2)', n is the number of slits in the resulting thermoelectric conversion element (i.e., the number of slits formed), R' is the electrical resistance of the thermoelectric conversion raw structure before processing, and Rn is the electrical resistance of portions (narrow portions) located on both sides of the slits in the width direction of the resulting thermoelectric conversion element.

[0085] Furthermore, in the production of the thermoelectric conversion element (a3), it is preferable to cut the thermoelectric conversion raw structure so that the widths of the cut pieces (thermoelectric conversion structures) of the thermoelectric conversion raw structure are all the same, and further, the widths of the cut pieces (thermoelectric conversion structures) are all equal, and the following relational expression (2') is satisfied: R' < Rn / n (2)' Here, in formula (2)', n is the number of gaps in the resulting thermoelectric conversion element (i.e., the number of cuts), R' is the electrical resistance of the thermoelectric conversion raw structure before processing, and Rn is the electrical resistance of the cut pieces (thermoelectric conversion structure) of the thermoelectric conversion raw structure.

[0086] <Joint member forming process> In the joining member forming step, the thermoelectric conversion elements and the electrodes are electrically joined using any conductive material such as solder or silver paste, thereby electrically connecting the thermoelectric conversion elements in series or in parallel.

[0087] Although the manufacturing method of the thermoelectric conversion module and the thermoelectric conversion element used in the thermoelectric conversion module has been described above, the manufacturing method of the present invention is not limited to the above. [Example]

[0088] The effects of the present invention will be specifically described below based on experimental examples.

[0089] (Experimental Example 1) A CNT sheet consisting solely of CNTs, prepared from an ethanol dispersion of carbon nanotubes (ZEON Corporation, ZEONANO SG101), was placed on a glass epoxy substrate to prepare a rectangular CNT film in plan view, measuring 20 mm in length, 4 mm in width, and 0.05 mm in thickness. The electrical resistance of the resulting CNT film was measured using a low-resistance resistivity meter (Nitto Seiko Analytech Co., Ltd., Loresta-GX MCP-T700), and was found to be 2.11 Ω. Next, three slits, each 17 mm long and 0.2 mm wide, were formed in the CNT film using a UV laser. Specifically, slits were formed at equal intervals of 0.85 mm, with both longitudinal ends terminating within the CNT film, resulting in a thermoelectric conversion element with a longitudinal length of 20 mm, a width of 4 mm, and a thickness of 0.05 mm. The electrical resistance of the resulting thermoelectric conversion element was measured using a low-resistance resistivity meter (Loresta-GX MCP-T700, manufactured by Nitto Seiko Analytech Co., Ltd.), and was found to be 1.75 Ω, a lower electrical resistance than before the slits were formed.

[0090] (Experimental Example 2) A CNT sheet consisting solely of CNTs, prepared from an ethanol dispersion of carbon nanotubes (ZEON Corporation, ZEONANO SG101), was placed on a glass epoxy substrate to prepare a rectangular CNT film in plan view, measuring 20 mm in length, 4 mm in width, and 0.05 mm in thickness. The electrical resistance of the resulting CNT film was measured using a low-resistance resistivity meter (Nitto Seiko Analytech Co., Ltd., Loresta-GX MCP-T700), and was found to be 2.11 Ω. Next, the CNT film was cut longitudinally using a UV laser, creating a 0.2 mm gap in the center of the width direction to separate the CNT film into two CNT film pieces. The longitudinal ends of the CNT film were then connected together with silver paste. This resulted in a thermoelectric conversion element in which two CNT film pieces, each 20 mm long, 1.9 mm wide, and 0.05 mm thick, were connected in parallel with a gap between them. The electrical resistance of the resulting thermoelectric conversion element was measured using a low-resistance resistivity meter (Loresta-GX MCP-T700, manufactured by Nitto Seiko Analytech Co., Ltd.), and was found to be 1.84 Ω, a lower value than before the slit was formed.

[0091] (Experimental Example 3) A CNT sheet consisting solely of CNTs, prepared from an ethanol dispersion of carbon nanotubes (ZEON Corporation, ZEONANO SG101), was placed on a glass epoxy substrate to prepare a rectangular CNT film in plan view, measuring 20 mm in length, 4 mm in width, and 0.05 mm in thickness. The electrical resistance of the resulting CNT film was measured using a low-resistance resistivity meter (Nitto Seiko Analytech Co., Ltd., Loresta-GX MCP-T700), and was found to be 2.11 Ω. Next, the CNT film was cut longitudinally using a UV laser, creating three equally spaced 0.2 mm gaps to divide the CNT film into four CNT film pieces. The longitudinal ends of each CNT film piece were then connected together with silver paste. A thermoelectric conversion element was obtained, consisting of two CNT film pieces, each 20 mm long, 0.85 mm wide, and 0.05 mm thick, connected in parallel with a gap between them. The electrical resistance of the resulting thermoelectric conversion element was measured using a low-resistance resistivity meter (Loresta-GX MCP-T700, manufactured by Nitto Seiko Analytech Co., Ltd.), and was found to be 1.65 Ω, a lower value than before the slits were formed.

[0092] From the above Experimental Examples 1 to 3, it can be seen that the thermoelectric conversion element having the above-described structure has a lower electrical resistance than a CNT film having the same external dimensions. This shows that the thermoelectric conversion module of the present invention using a thermoelectric conversion element having a predetermined structure can exhibit excellent power generation efficiency. [Industrial Applicability]

[0093] According to the present invention, it is possible to provide a thermoelectric conversion element having a lower electrical resistance. Furthermore, according to the present invention, it is possible to provide a thermoelectric conversion module with excellent power generation efficiency. [Explanation of symbols]

[0094] 1 sheet substrate 2 Thermoelectric conversion element 2A~2E Thermoelectric conversion elements 2a,2b edge 3 Joint materials 4 electrodes 5. Wiring 20 Thermoelectric conversion structure 20a,20b end 21 Slit 21a,21b edge 22 Narrow section 23a, 23b wide section 24 Joint 24a First joint 24b Second joint 25 Gap 100,200 Series-connected thermoelectric conversion module 300 Parallel-connected thermoelectric conversion modules

Claims

1. A thermoelectric conversion module including a plurality of elongated thermoelectric conversion elements electrically connected in series via longitudinal end portions, The plurality of thermoelectric conversion elements electrically connected in series include one or more thermoelectric conversion elements (A) each consisting of a thermoelectric conversion element (a1), The thermoelectric conversion element (a1) is a long thermoelectric conversion structure having at least one slit extending in the longitudinal direction and terminating at both ends within the thermoelectric conversion structure, and has electrodes electrically connected to both ends in the longitudinal direction.

2. The thermoelectric conversion element (A) satisfies the following relational expression (1): S<W / n...(1) (In formula (1), n ​​is the number of slits, S is the total width of the slits, and W is the width of the thermoelectric conversion element (A).) The thermoelectric conversion module according to claim 1 , which satisfies the above.

3. The thermoelectric conversion element (A) has two or more of the slits, The thermoelectric conversion module according to claim 1 , wherein all of the slits have the same shape.

4. 4. The thermoelectric conversion module according to claim 1, wherein the long thermoelectric conversion structure has conductive materials arranged in a non-oriented state.

5. The thermoelectric conversion module according to claim 4 , wherein the conductive material is a fibrous carbon material.

6. The thermoelectric conversion module according to claim 5 , wherein the fibrous carbon material is a carbon nanotube.

7. The thermoelectric conversion structure has an elongated shape and at least one slit formed therein. the slit extends in the longitudinal direction of the thermoelectric conversion structure, and both ends thereof terminate within the thermoelectric conversion structure; A thermoelectric conversion element having electrodes electrically connected to both ends in the longitudinal direction.

8. A thermoelectric conversion module including a plurality of elongated thermoelectric conversion elements electrically connected in parallel via longitudinal end portions, A thermoelectric conversion module, wherein the plurality of thermoelectric conversion elements electrically connected in parallel include one or more thermoelectric conversion elements according to claim 7.

9. 8. A method for manufacturing a thermoelectric conversion element according to claim 7, comprising the step of forming slits in the long thermoelectric conversion raw structure.

10. A method for manufacturing a thermoelectric conversion module according to any one of claims 1 to 6, A method for producing a thermoelectric conversion module, comprising the step of forming slits in a long thermoelectric conversion raw structure to produce a thermoelectric conversion element (a1).

11. A method for manufacturing a thermoelectric conversion module according to claim 8, A method for manufacturing a thermoelectric conversion module, comprising the step of manufacturing a thermoelectric conversion element using the method for manufacturing a thermoelectric conversion element according to claim 9.

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