Thermoelectric conversion module

Abstract

To provide a thermoelectric conversion module capable of continuously using a thermal power generation system even when some of the multiple thermoelectric conversion modules are failed due to being exposed to high temperatures.SOLUTION: In a disclosed method of using a thermal power generation system, under a temperature atmosphere above the melting point of the low-melting-point conductor, a low-melting-point conductor included in at least one of the multiple thermoelectric conversion modules melts, the molten low-melting-point conductor short-circuits a pair of external terminals included in at least one of the multiple thermoelectric conversion modules, and the molten low-melting-point conductor activates at least one other of the multiple thermoelectric conversion modules.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a thermoelectric conversion module. [Background technology]

[0002] A thermoelectric conversion element is an element that can convert heat into electricity or electricity into heat. A thermoelectric conversion element made of a thermoelectric material that exhibits the Seebeck effect can obtain thermal energy from a relatively low-temperature heat source (for example, 200°C or less) and convert it into electricity. For example, thermal power generation technology using such a thermoelectric conversion element makes it possible to recover and effectively utilize thermal energy that was previously discarded in the surrounding environment in the form of steam, hot water, exhaust gas, etc.

[0003] A typical thermoelectric conversion element has a pair of a p-type thermoelectric conversion element and an n-type thermoelectric conversion element whose carriers have different electrical polarities, that is, a so-called "π-type structure". This structure is disclosed, for example, in Non-Patent Document 1. In a thermoelectric conversion element of the "π-type structure", a p-type thermoelectric conversion element and an n-type thermoelectric conversion element are electrically connected in series and thermally connected in parallel. In this specification, a pair of a p-type thermoelectric conversion element and an n-type thermoelectric conversion element is called a "thermoelectric conversion element pair". A thermoelectric conversion module is formed by electrically connecting a plurality of thermoelectric conversion element pairs to each other in series. The thermoelectric conversion module includes, for example, about several tens of thermoelectric conversion element pairs. By converting thermal energy into electric power, a voltage of, for example, several mV to several V can be obtained from the thermoelectric conversion module. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-9779 A [Patent Document 2] JP 2016-35882 A [Non-patent literature]

[0005] [Non-Patent Document 1] G. JEFFREY SNYDER and ERIC S. TOBERER, “Complex thermoelectric materials”, Nature Materials, Vol. 7, No. 2, 2008, pp. 105-114 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to generate more power, a thermoelectric power generation system may be constructed by electrically connecting multiple thermoelectric conversion modules in series. In this thermoelectric power generation system, if one of the multiple thermoelectric conversion modules fails, electrical continuity in the entire thermoelectric power generation system is lost because the multiple thermoelectric conversion modules are connected in series. Even in such a case, it is desirable to continue using the thermoelectric power generation system.

[0007] An exemplary embodiment of the present disclosure provides a thermoelectric conversion module that allows the thermoelectric power generation system to continue to be used even if some of the multiple thermoelectric conversion modules are exposed to high temperatures and fail. [Means for solving the problem]

[0008] The thermoelectric conversion module of the present disclosure includes a substrate, a plurality of thermoelectric conversion element pairs electrically connected in series and provided on the substrate, a pair of external terminals for inputting or outputting electric power and a low-melting-point conductor provided on the substrate, wherein each of the plurality of thermoelectric conversion element pairs has a p-type thermoelectric conversion element and an n-type thermoelectric conversion element, the low-melting-point conductor has a melting point approximately equal to the heat-resistant temperature of the p-type thermoelectric conversion element or the n-type thermoelectric conversion element, one of the pair of external terminals has a first connection portion electrically connected to a p-type thermoelectric conversion element at one end side of the plurality of thermoelectric conversion element pairs, and the other of the pair of external terminals has a first connection portion electrically connected to the p-type thermoelectric conversion element at one end side of the plurality of thermoelectric conversion element pairs. The substrate has a second connection portion electrically connected to an n-type thermoelectric conversion element at the other end of the pair, the first connection portion and the second connection portion being located in an inner region surrounded by an outer region of the substrate, the outer region including a region in which a plurality of the p-type thermoelectric conversion elements and a plurality of the n-type thermoelectric conversion elements arranged at the outermost positions within the surface of the substrate are present, the low-melting point conductor is located in the inner region surrounded by the outer region of the substrate, and at least a portion of the low-melting point conductor is located between the pair of external terminals when viewed from a normal direction of the substrate, and the low-melting point conductor is electrically insulated from at least one of the pair of external terminals. Effect of the Invention

[0009] According to an exemplary embodiment of the present disclosure, a thermoelectric conversion module is provided that enables continued use of a thermoelectric power generation system by utilizing unfailed thermoelectric conversion modules even if some of a plurality of thermoelectric conversion modules are exposed to high temperatures and fail. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view illustrating a schematic configuration of a thermoelectric conversion module 100 according to an exemplary embodiment. [Diagram 2] FIG. 2 is a plan view that illustrates a schematic configuration of a thermoelectric conversion module 100 according to an exemplary embodiment. [Diagram 3]FIG. 3 is an enlarged schematic diagram showing a pair of external terminals 40 and p-type thermoelectric conversion element 21P and n-type thermoelectric conversion element 21N electrically connected thereto. [Figure 4A] FIG. 4A is an enlarged schematic diagram showing a low melting point conductor 60 provided on a substrate 10H. [Figure 4B] FIG. 4B is an enlarged schematic diagram showing a low melting point conductor 60 provided on the substrate 10H. [Diagram 5] FIG. 5 is a schematic diagram showing a low melting point conductor 60 supported by a support 61 provided between a pair of external terminals 40. As shown in FIG. [Figure 6] FIG. 6 is a schematic diagram showing a state in which a pair of external terminals 40 are short-circuited by a molten low-melting point conductor 60. As shown in FIG. [Figure 7] FIG. 7 is a schematic diagram showing a groove 70 provided in the substrate 10H for guiding the molten low melting point conductor 60. As shown in FIG. [Figure 8A] FIG. 8A is a perspective view illustrating a typical configuration of a conventional thermoelectric conversion module 200. As shown in FIG. [Figure 8B] FIG. 8B is a plan view that illustrates a schematic configuration of the conventional thermoelectric conversion module 200. As shown in FIG. [Figure 9] FIG. 9 is a plan view that illustrates a schematic configuration of a thermoelectric conversion module 200 that includes a switch SW that shorts a pair of external terminals 40. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Before describing the embodiments of the present disclosure, the findings of the present inventors on which the present disclosure is based will be described.

[0012] Fig. 8A shows a typical configuration of a conventional thermoelectric conversion module 200. Fig. 8B shows a schematic diagram of the arrangement and wiring of a plurality of thermoelectric conversion element pairs 20 on a substrate 10C on the low-temperature heat source side when the thermoelectric conversion module 200 is viewed from the normal direction of the substrate (z direction in the drawing). The configuration of the conventional thermoelectric conversion module 200 is as disclosed in, for example, Non-Patent Document 1. To avoid cluttering the drawing, a part of the substrate 10H on the high-temperature heat source side is omitted in Fig. 8A.

[0013] The thermoelectric conversion module 200 includes a substrate 10H on the high-temperature heat source side, a substrate 10C on the low-temperature heat source side, a plurality of thermoelectric conversion element pairs 20 sandwiched between the two substrates, and a pair of external terminals 40. Hereinafter, the substrate 10H on the high-temperature heat source side and the substrate 10C on the low-temperature heat source side may be simply referred to as substrate 10H and substrate 10C, respectively. At least the surfaces of these substrates are formed of an insulating material. The thermoelectric conversion element pairs 20 have a p-type thermoelectric conversion element 21P and an n-type thermoelectric conversion element 21N. For example, the plurality of p-type thermoelectric conversion elements 21P and the plurality of n-type thermoelectric conversion elements 21N are arranged in a lattice pattern on the substrate 10C on the low-temperature heat source side. The plurality of thermoelectric conversion element pairs 20 are electrically connected in series to each other by wiring 30H provided on the substrate 10H and wiring 30C provided on the substrate 10C. The p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N are joined to the wirings 30H, 30C using, for example, solder or an adhesive.

[0014] The pair of external terminals 40 are terminals for inputting or outputting electric power to the thermoelectric conversion module 200. The pair of external terminals 40 are electrically connected to the multiple thermoelectric conversion element pairs 20 connected in series with each other. In consideration of the arrangement and wiring efficiency of the multiple thermoelectric conversion element pairs 20, the pair of external terminals 40 are typically arranged at the corners of the substrate 10C as shown in FIG. 8A.

[0015] By heating the substrate 10H and cooling the substrate 10C, that is, by heating the substrate 10H and not heating the substrate 10C, a temperature difference occurs between the p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N of the thermoelectric conversion element pair 20. An electromotive force is generated by the Seebeck effect. The thermoelectric conversion module 200 converts thermal energy into electric power. The electric power generated inside the thermoelectric conversion module 200 can be taken out from a pair of external terminals 40.

[0016] When a current is injected into the thermoelectric conversion module 200 from the pair of external terminals 40, for example, heat absorption occurs on the surface of one substrate 10C and heat dissipation occurs on the surface of the other substrate 10H due to the Peltier effect. The thermoelectric conversion module 200 converts electric power into thermal energy. In this way, the thermoelectric conversion module 200 can also perform cooling and heating using electric power.

[0017] For example, a failure in the cooling function may cause the thermoelectric conversion module 200 to reach a higher temperature than during normal operation. In this case, cracks are likely to occur due to thermal expansion, particularly at the joints between the thermoelectric conversion elements and the wiring. This is believed to be due to the thermal expansion coefficient of the material or the difference in the thermal expansion coefficient between the materials. If even one of the multiple thermoelectric conversion element pairs 20 fails in this way, the thermoelectric conversion module 200 will be in an electrically disconnected state. As a result, the thermoelectric conversion module 200 will no longer function.

[0018] For example, a thermoelectric power generation system can be configured using a plurality of thermoelectric conversion modules 200. In the thermoelectric power generation system, the plurality of thermoelectric conversion modules are typically electrically connected in series. By connecting more thermoelectric conversion modules, a larger amount of power can be generated.

[0019] Suppose that a disconnection occurs in one of the thermoelectric conversion modules 200. In that case, electrical continuity is lost in the thermoelectric power generation system as a whole even if no disconnection occurs in the remaining thermoelectric conversion modules 200. For example, if the thermoelectric conversion module 200 is exposed to a high temperature equal to or higher than a specified temperature, the thermoelectric power generation system will no longer function.

[0020] In order to solve the above problem, a technique has been devised for maintaining electrical continuity of the entire system by shorting a pair of external terminals 40. Patent Document 1 discloses a technique for shorting a current input terminal using an electrical conductive part only when the temperature is high. When the thermoelectric conversion module reaches a high temperature, the internal bonding material melts. As a result, the thickness of the thermoelectric conversion module decreases due to the substrate sinking. By utilizing this phenomenon, the current input terminal is shorted by electrically contacting the electrical conductive part only when a high temperature state is reached. Patent Document 2 discloses a temperature short-circuit element that operates in a temperature atmosphere above the melting point of a fusible conductor that melts at high temperatures. In a temperature atmosphere above the melting point of the fusible conductor, the fusible conductor melts and solidifies, thereby shorting two adjacent electrodes.

[0021] As described above, in the configuration of the conventional thermoelectric conversion module 200, the pair of external terminals 40 are located particularly at the corners of the outer region 50 of the module. In this specification, the outer region 50 refers to the region indicated by the dashed lines in which the group of thermoelectric conversion element pairs 20 arranged on the outermost side out of the multiple thermoelectric conversion element pairs 20 arranged in a lattice pattern is located within the entire region of the substrate.

[0022] 9 is a schematic diagram showing the configuration of a thermoelectric conversion module 200 that is equipped with a switch SW capable of short-circuiting a pair of external terminals 40. The switch SW may be a fusible conductor, as in Patent Document 2, for example. By replacing the thermoelectric conversion element pair 20 between the pair of external terminals 40 with the switch SW, the configuration shown in FIG. 9 is obtained. In this configuration, the switch SW is disposed between the pair of external terminals 40. When simply replaced in this way, the switch SW is necessarily disposed in the outer region 50 of the substrate 10C.

[0023] In fact, since heat is also released from the side surfaces of the thermoelectric conversion module 200, the outer region 50 is less likely to become hotter than the vicinity of the center of the substrate 10C. Therefore, for example, due to a failure in the cooling function, the vicinity of the center of the thermoelectric conversion module 200 reaches a temperature at which the electrical connection between the multiple thermoelectric conversion element pairs 20 is cut off. Even in that case, the outer region 50 may not reach that temperature. As a result, if a switch SW is simply provided in the conventional configuration, there is a high possibility that the switch SW that short-circuits the pair of external terminals 40 will not function normally. Also, in the conventional configuration, the pair of external terminals 40 are separated. Therefore, it is considered that simply providing a switch SW between the terminals is insufficient to short-circuit the terminals.

[0024] Furthermore, in the conventional configuration, even if the switch SW is provided on the board 10C on the low-temperature heat source side, there is a problem that a sufficient amount of heat to make it function is not transferred. As shown in Non-Patent Document 1, the pair of external terminals 40 are generally provided on the board 10C on the low-temperature heat source side. One of the reasons for this is that if external terminals are provided on the board 10H on the high-temperature heat source side, they function as a heat sink, making it easier for heat to be dissipated from there.

[0025] A technique for more accurately short-circuiting a pair of external terminals when a thermoelectric conversion module is exposed to high temperatures is desired. Based on the above findings, the present inventors have discovered that a low-melting-point conductor can be provided in an inner region surrounded by an outer region of a substrate on the high-temperature heat source side, and have arrived at the present disclosure.

[0026] Exemplary embodiments Hereinafter, embodiments of a thermoelectric conversion module according to the present disclosure will be described with reference to the accompanying drawings.

[0027] FIG. 1 is a schematic diagram of a thermoelectric conversion module 100 according to the present embodiment. In order to avoid the drawing becoming complicated, a part of the substrate 10C on the low-temperature heat source side is omitted in FIG. 1. FIG. 2 is a schematic diagram of the arrangement and wiring of a plurality of thermoelectric conversion element pairs 20 on the substrate 10H on the high-temperature heat source side when the thermoelectric conversion module 100 is viewed from the normal direction of the substrate 10H (z direction in the drawing). In this specification, an embodiment of the present disclosure will be described using as an example a thermoelectric conversion module 100 having two substrates 10H and 10C on the high-temperature heat source side and the low-temperature heat source side. However, a thermoelectric conversion module that does not have a substrate 10C on the low-temperature heat source side is also known. Such a module may be called a "half skeleton type". The half skeleton type thermoelectric conversion module is also within the scope of the present disclosure. Hereinafter, explanations that overlap with the above-mentioned conventional configuration will be omitted.

[0028] The thermoelectric conversion module 100 includes a substrate 10H on the high-temperature heat source side, a substrate 10C on the low-temperature heat source side, a plurality of thermoelectric conversion element pairs 20, a pair of external terminals 40, and a low-melting-point conductor 60. The materials of the substrate 10H on the high-temperature heat source side and the substrate 10C on the low-temperature heat source side are not particularly limited as long as at least their surfaces have electrical insulation. However, materials with high thermal conductivity and high heat resistance are preferred. For example, aluminum oxide can be suitably used as the material.

[0029] The multiple thermoelectric conversion element pairs 20, more specifically the multiple p-type thermoelectric conversion elements 21P and the multiple n-type thermoelectric conversion elements 21N, are typically arranged in a lattice pattern on the substrate 10H on the high-temperature heat source side. The size of the substrates 10C and 10H in the x direction is, for example, 1 cm to 6 cm. The size in the y direction is, for example, 1 cm to 6 cm. The size in the x direction of each of the p-type thermoelectric conversion elements 21P and the n-type thermoelectric conversion elements 21N is, for example, 1.0 mm to 3.0 mm. The size in the y direction is, for example, 1.0 mm to 3.0 mm. The height in the z direction is, for example, about 1.0 mm to 3.0 mm. It should be noted that the arrangement and wiring of the multiple thermoelectric conversion element pairs 20 is not limited to the example shown in the figure.

[0030] Each of the p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N includes at least a thermoelectric conversion material. The type of the thermoelectric conversion material is not particularly limited. For example, the thermoelectric conversion material can be selected according to the temperature of the intended use. For example, when the thermoelectric conversion module 100 is used in a temperature range from room temperature to about 200°C, a Bi-Te-based material is preferable. When the thermoelectric conversion module 100 is used in a temperature range from about 200°C to 500°C, a Pb-Te-based material, a Co-Sb-based material, a Zn-Sb-based material, or a Mg-Sb-based material is preferable. When the thermoelectric conversion module 100 is used in a temperature range from about 500°C to 1000°C, a Si-Ge-based material is preferable.

[0031] 3 shows an enlarged view of a pair of external terminals 40 and the p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N electrically connected thereto. As shown in FIG. 2, the pair of external terminals 40 are provided on the substrate 10H on the high-temperature heat source side. The pair of external terminals 40 are terminals for extracting the electric power generated in the multiple thermoelectric conversion element pairs 20 to the outside. The pair of external terminals 40 are disposed adjacent to the substrate 10H with a distance w therebetween. For example, the distance w is equal to the distance between the p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N in the thermoelectric conversion element pair 20.

[0032] One of the pair of external terminals 40 has a first connection portion 42 having a contact surface with the p-type thermoelectric conversion element 21P. The first connection portion 42 is electrically connected to the p-type thermoelectric conversion element 21P at one end side of the plurality of thermoelectric conversion element pairs 20 connected in series with each other. The other of the pair of external terminals 40 has a second connection portion 43 having a contact surface with the n-type thermoelectric conversion element 21N. The second connection portion 43 is electrically connected to the n-type thermoelectric conversion element 21N at the other end side of the plurality of thermoelectric conversion element pairs 20. As shown in FIG. 2, the first connection portion 42 and the second connection portion 43 are located in an inner region 51 surrounded by an outer region 50 of the substrate 10H. Furthermore, the first connection portion 42 and the second connection portion 43 are close to each other near the center of the substrate 10H. The center of the substrate 10H refers to the intersection of the diagonals of the substrate, which is substantially rectangular. However, the first connection portion 42 and the second connection portion 43 only need to be located in the inner region 51 of the substrate 10H, and do not necessarily have to be located near the center.

[0033] The materials of the wiring 30H, the wiring 30C, and the pair of external terminals 40 are not particularly limited. However, materials with high electrical conductivity and high heat resistance are preferable. For example, copper or silver wiring can be used as the material. The line widths of the wiring 30H, the wiring 30C, and the pair of external terminals 40 are appropriately determined based on the amount of current that can flow through the thermoelectric conversion module 100.

[0034] The low melting point conductor 60 is provided in the inner region 51 of the substrate 10H. At least a portion of the low melting point conductor 60 may be located between the pair of external terminals 40 when viewed from the normal direction of the substrate 10H (z direction in FIG. 2). For example, the low melting point conductor 60 is located between the pair of external terminals 40 as shown in FIG. 2. The low melting point conductor 60 is preferably provided near the center of the substrate 10H. This allows heat to be more efficiently transferred to the low melting point conductor 60 when the thermoelectric conversion module 100 is exposed to high temperatures. As a result, it becomes possible to more accurately short-circuit the pair of external terminals 40.

[0035] 4A and 4B show an enlarged view of the low melting point conductor 60 provided on the substrate 10H. FIG. 5 shows the low melting point conductor 60 supported by a support 61 provided between a pair of external terminals 40. The low melting point conductor 60 has a dome-shaped or rectangular columnar shape, for example. In an atmosphere with a temperature lower than the melting point of the low melting point conductor 60, the low melting point conductor 60 is electrically insulated from at least one of the pair of external terminals 40. For example, as shown in the figure, the low melting point conductor 60 can be electrically insulated by providing a gap between the low melting point conductor 60 and the pair of external terminals 40. Alternatively, a gap may be provided between the low melting point conductor 60 and one of the pair of external terminals 40 while the low melting point conductor 60 is in contact with the other of the pair of external terminals 40. In either case, the pair of external terminals 40 is not short-circuited. In this way, the low melting point conductor 60 does not affect the module operation, i.e., the input or output of current. The thermoelectric conversion module 100 operates in a temperature atmosphere below the melting point of the low-melting-point conductor 60 in the same manner as a conventional thermoelectric conversion module 200 .

[0036] As a method for electrically insulating the low melting point conductor 60, a support 61 may be provided between the pair of external terminals 40 as shown in Fig. 5. The low melting point conductor 60 may be electrically insulated by providing, for example, a plate-shaped low melting point conductor 60 on the support 61. In this case, at least a part of the low melting point conductor 60 is located between the pair of external terminals 40 when viewed from the normal direction of the substrate 10H (z direction in Fig. 2), and the remainder overlaps the pair of external terminals 40. Alternatively, the low melting point conductor 60 may be electrically insulated by sandwiching an insulating film instead of a gap between the low melting point conductor 60 and the pair of external terminals 40.

[0037] The low-melting-point conductor 60 has a melting point substantially equal to the heat-resistant temperature of the p-type thermoelectric conversion element 21P or the n-type thermoelectric conversion element 21N. More specifically, the melting point of the low-melting-point conductor 60 satisfies at least the following formula (I) or (II). Tp×0.90≦Tm≦Tp×1.1 (I) Tn×0.90≦Tm≦Tn×1.1 (II) Here, Tm is the melting point of the low melting point conductor 60. Tp is the heat resistance temperature of the p-type thermoelectric conversion element 21P. Tn is the heat resistance temperature of the n-type thermoelectric conversion element 21N. The heat resistance temperature is the temperature at which the series connection of the multiple thermoelectric conversion element pairs 20 is broken due to thermal expansion of at least one of the multiple thermoelectric conversion element pairs 20.

[0038] The melting point of the low melting point conductor 60 must be higher than the maximum temperature expected to be reached during normal use of the thermoelectric conversion module 100. Therefore, it is preferable that the melting point of the low melting point conductor 60 is approximately the same as the heat resistance temperature at which the module may be damaged. The low melting point conductor 60 is, for example, a low melting point metal. For example, consider a case where a Bi-Te-based material is used as the material of the thermoelectric conversion element. In that case, the thermoelectric conversion module 100 is usually used in a temperature range of about 100°C or less, and is prone to damage when the temperature exceeds 200°C. Therefore, for example, an In-Sn alloy or an In-Bi alloy is suitable as the low melting point conductor 60. The melting point of the In-Sn alloy can be adjusted in the range of 117°C to 232°C by adjusting the mixture ratio of In and Sn. The melting point of the In-Bi alloy can be adjusted in the range of 72°C to 271°C by adjusting the mixture ratio of In and Bi.

[0039] For example, by changing the thermoelectric conversion element used, the heat resistance of the thermoelectric conversion module 100 can be improved, and it can be used at higher temperatures. In this case, for example, an Sn-Sb alloy or an Sn-Cu alloy is suitable as the low melting point conductor 60. The melting point of the Sn-Sb alloy can be adjusted in the range of 232°C to 630°C by adjusting the mixture ratio of Sn and Sb. The melting point of the Sn-Cu alloy can be adjusted in the range of 223°C to 1083°C by adjusting the mixture ratio of Sn and Cu.

[0040] In one embodiment, the low melting point conductor 60 is an In—Sn alloy, the melting point of which is not less than 200° C. and not more than 232° C. Each of the p-type thermoelectric conversion element 21P and the n-type thermoelectric conversion element 21N is made of a Bi—Te based material.

[0041] FIG. 6 shows a state in which a pair of external terminals 40 are short-circuited by a molten low-melting point conductor 60.

[0042] In a temperature atmosphere above the melting point of the low-melting-point conductor 60, the pair of external terminals 40 are short-circuited by the molten low-melting-point conductor 60. For example, if the cooling function on the low-temperature heat source side fails, more heat may be trapped in the thermoelectric conversion module 100 than during normal use. Therefore, the module temperature may rise to near the heat-resistant limit temperature. Then, since the melting point of the low-melting-point conductor 60 is about the same as the heat-resistant temperature, the low-melting-point conductor 60 may melt and diffuse. The molten low-melting-point conductor 60 electrically contacts both of the pair of external terminals 40, and as a result, the pair of external terminals 40 are short-circuited. The low-melting-point conductor 60 has electrical conductivity in either a liquid or solid state. Therefore, the state of the low-melting-point conductor 60 once melted may be solid or liquid depending on the temperature inside the module. In the thermoelectric power generation system, the damaged thermoelectric conversion module 100 will no longer function, but electrical continuity is ensured among the multiple thermoelectric conversion modules 100 connected in series with each other. In this way, as long as the remaining thermoelectric conversion modules 100 are not damaged, the thermoelectric power generation system can be used continuously.

[0043] According to this embodiment, by providing the low melting point conductor 60 in the inner region 51 of the substrate 10H and arranging the pair of external terminals 40 closely to each other, it is possible to reduce the influence of heat radiation from the side surface of the thermoelectric conversion module 100. As a result, the thermoelectric conversion module 100 operates more accurately than the conventional thermoelectric conversion module 200 when the module temperature rises close to the heat resistance limit.

[0044] FIG. 7 shows a groove 70 in the substrate 10H for guiding the molten low melting point conductor 60.

[0045] The substrate 10H may have a groove 70 for guiding the molten low-melting-point conductor 60. In this case, at least a part of the low-melting-point conductor 60 may be provided in the groove 70. By providing the groove 70, the range in which the low-melting-point conductor 60 diffuses when melted can be limited to a range necessary and sufficient to short-circuit the pair of external terminals 40. This allows the thermoelectric conversion module 100 to operate more accurately.

[0046] In this embodiment, a configuration in which a single low melting point conductor 60 is provided on the substrate 10H has been described. However, the present disclosure is not limited to this. One or more other low melting point conductors (not shown) may be further provided between the pair of external terminals 40. In this way, even if one low melting point conductor does not function well, the other low melting point conductors can function, allowing the pair of external terminals 40 to be short-circuited more accurately.

[0047] The thermoelectric conversion module 100 can be configured with the same elements as the conventional thermoelectric conversion module 200, except for the low melting point conductor 60. Therefore, a wide variety of known methods can be used to manufacture the thermoelectric conversion module 100. The low melting point conductor 60 is mounted by using, for example, a soldering or printed wiring method. [Industrial Applicability]

[0048] The thermoelectric conversion module according to the present disclosure can be suitably used in a thermoelectric conversion device that converts thermal energy into electric power and vice versa. [Explanation of symbols]

[0049] 10H, 10C: Substrate 20: Thermoelectric conversion element pair 21P: p-type thermoelectric conversion element 21N: n-type thermoelectric conversion element 30H, 30C: Wiring 40: A pair of external terminals 42: First connection part 43: Second connection part 50:Outer area 51 :Inner area 60: Low melting point conductor 61:Support 70: Groove 100: Thermoelectric conversion module

Claims

1. A method for using a thermoelectric power generation system in which a plurality of thermoelectric conversion modules are electrically connected in series, comprising the steps of: Each of the plurality of thermoelectric conversion modules is The substrate on the high-temperature heat source side, a plurality of thermoelectric conversion element pairs electrically connected in series; A pair of external terminals for inputting or outputting power; and Low melting point conductor, Equipped with Each of the plurality of thermoelectric conversion element pairs has a p-type thermoelectric conversion element and an n-type thermoelectric conversion element, The pair of external terminals are provided adjacent to each other across the center of the substrate, the low melting point conductor is provided in a region near the center of the substrate and between the pair of external terminals, At least a portion of the low melting point conductor is located between the pair of external terminals, The melting point of the low melting point conductor satisfies at least the following formula (I) or formula (II): Tp×0.90≦Tm≦Tp×1.1 (I) Tn×0.90≦Tm≦Tn×1.1 (II) Here, Tm is the melting point, Tp is the heat resistance temperature of the p-type thermoelectric conversion element, and Tn is the heat resistance temperature of the n-type thermoelectric conversion element. the low-melting-point conductor is electrically insulated from at least one of the pair of external terminals in an atmosphere having a temperature lower than the melting point of the low-melting-point conductor; The low-melting-point conductor provided in at least one of the plurality of thermoelectric conversion modules melts in an atmosphere having a temperature equal to or higher than the melting point of the low-melting-point conductor, the pair of external terminals provided on at least one of the plurality of thermoelectric conversion modules are short-circuited by the molten low-melting point conductor; activating at least one other of the plurality of thermoelectric conversion modules by the molten low-melting-point conductor; How to use a thermal power generation system.

2. The plurality of thermoelectric conversion element pairs and the pair of external terminals are provided on the substrate. A method for using the thermoelectric power generation system according to claim 1 .

3. one of the pair of external terminals has a first connection portion electrically connected to a p-type thermoelectric conversion element at one end side of the plurality of thermoelectric conversion element pairs; the other of the pair of external terminals has a second connection portion electrically connected to an n-type thermoelectric conversion element at the other end of the plurality of thermoelectric conversion element pairs; A method for using the thermoelectric power generation system according to claim 2.

4. the first connection portion and the second connection portion are located in an inner region surrounded by an outer region of the substrate, The outer region includes a region in which a plurality of the p-type thermoelectric conversion elements and a plurality of the n-type thermoelectric conversion elements are provided on the outermost side within a surface of the substrate. A method for using the thermoelectric power generation system according to claim 3.

5. Each of the plurality of thermoelectric conversion modules further includes another low melting point conductor provided between the pair of external terminals. A method for using the thermoelectric power generation system according to any one of claims 1 to 4.

6. The melting point of the low melting point conductor is a temperature at which the series connection of the plurality of thermoelectric conversion element pairs is broken due to thermal expansion of at least one of the plurality of thermoelectric conversion element pairs. A method for using the thermoelectric power generation system according to any one of claims 1 to 4.

7. the substrate has a groove for guiding the molten low melting point conductor; At least a portion of the low melting point conductor is provided in the groove. A method for using the thermoelectric power generation system according to any one of claims 1 to 6.

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