Fuel cell module and fuel cell device

Abstract

The fuel cell module includes a fuel cell stack, a terminal, a bus bar, a first junction, a second junction, and a container. The terminal outputs electric power generated by the fuel cell stack. And connecting the bus bar with the terminal. The first joining portion (14) joins the terminal and the bus bar. The second joining portion joins the bus bar and the outer conductor at a position different from the terminal. The linear expansion coefficient of the first joining portion is equal to or less than the linear expansion coefficient of the

Description

[0001] Cross-references between related applications

[0002] This application claims priority from Japanese Patent Application No. 2023-13585 filed in Japan on January 31, 2023, and the disclosure of that prior application is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to a fuel cell module and a fuel cell device. Background Art

[0004] A fuel cell module has been proposed in which a fuel cell stack is housed in a container. In the fuel cell module, electric power is output from the fuel cell stack via a conductive portion that penetrates the container (see Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-016452 Summary of the Invention

[0008] The fuel cell module according to the first aspect has:

[0009] A fuel cell stack having a plurality of fuel cell cells stacked on top of each other;

[0010] a terminal for outputting the power generated by the fuel cell stack;

[0011] a busbar connected to the terminal;

[0012] a first engaging portion engaging the terminal with the busbar;

[0013] a second joint portion that joins an outer conductor to the bus bar at a position different from that of the terminal; and

[0014] a container that houses the fuel cell stack, the terminal, and the first joint, and houses a portion of the bus bar;

[0015] The linear expansion coefficient of the first joining portion is equal to or less than the linear expansion coefficient of the generatrix.

[0016] The fuel cell device based on the second viewpoint includes a fuel cell module and an auxiliary machine, wherein the fuel cell module includes: a fuel cell cell stack, which has a plurality of fuel cell cells stacked on each other; a terminal, which outputs the power generated by the fuel cell cell stack; a bus bar, which is connected to the terminal; a first joint, which joins the terminal to the bus bar; a second joint, which joins the external conductor to the bus bar at a position different from the terminal; and a container, which accommodates the fuel cell cell stack, the terminal, and the first joint, and accommodates a part of the bus bar, the linear expansion coefficient of the first joint is less than the linear expansion coefficient of the bus bar, and the auxiliary machine has an auxiliary function of causing the fuel cell module to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a side view of the fuel cell module of this embodiment, cut away, showing the interior together with the container.

[0018] Figure 2 It shows Figure 1 An enlarged perspective view of the structure near the terminal.

[0019] Figure 3 yes Figure 1 A three-dimensional view of the interior of a container of a fuel cell module.

[0020] Figure 4 It is shown from Figure 3 A plan view of the fuel cell module with the reformer removed and the supply pipe cut away at the position of the plate portion in the second direction. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the components shown in the following drawings, the same components are denoted by the same reference numerals.

[0022] like Figure 1 As shown, a fuel cell module 10 according to one embodiment of the present invention includes a fuel cell stack 11, terminals 12, bus bars 13, a first joint 14, a second joint 15, and a container 16. The fuel cell module 10 may further include an insulating portion 17, a manifold 18, a supply pipe 19, and a reformer 20.

[0023] The fuel cell stack 11 may include a plurality of stacked fuel cells 21. The fuel cell cells 21 may be solid oxide fuel cells. The fuel cell cells 21 generate electricity through an electrochemical reaction between the fuel generated in the reformer 20 and an oxidant such as oxygen contained in air. The plurality of fuel cell cells 21 may be connected in series, in parallel, or in a combination thereof.

[0024] The terminal 12 is electrically connected to the fuel cell stack 11. The terminal 12 outputs the power generated by the fuel cell stack 11. The terminal 12 may have a portion extending in a first direction away from the fuel cell stack 11. Specifically, the portion may extend parallel to the stacking direction of the fuel cells 21 in the fuel cell stack 11.

[0025] like Figure 2 As shown, the terminal 12 may have a flat portion 22. This flat portion 22 may be located at the position farthest from the fuel cell stack 11 in the terminal 12. This flat portion 22 may be perpendicular to the second direction. The second direction is a direction perpendicular to the first direction and is assumed to be vertically downward when the fuel cell device including the fuel cell module 10 is installed.

[0026] The terminal 12 may be formed of a material having heat resistance, elasticity, and conductivity. The terminal 12 may be formed of a material containing a magnetic body. Specifically, the terminal 12 may be formed of ferritic stainless steel.

[0027] The busbar 13 is connected to the terminal 12. The busbar 13 may be rod-shaped as a whole. The busbar 13 may include a flat portion 23 and a cylindrical portion 24. The flat portion 23 may be coupled to the cylindrical portion 24 in a manner parallel to the axial direction of the cylindrical portion 24.

[0028] The busbar 13 may be connected to the terminal 12 at the flat plate portion 23. Specifically, the busbar 13 may be connected to the terminal 12 such that the flat plate portion 22 of the terminal 12 is in surface contact with the flat plate portion 23 of the busbar 13. The busbar 13 may be connected to the terminal 12 so as to extend in the first direction.

[0029] An external thread may be formed on the end portion of the busbar 13 on the opposite side from the flat plate-shaped portion 23 .

[0030] The linear expansion coefficient of busbar 13 can be closer to that of terminal 12 than that of second joining portion 15. A close linear expansion coefficient means that the difference in linear expansion coefficient is small. Busbar 13 can be formed from a material containing a magnetic substance. The material of busbar 13 can be the same as that of terminal 12. Busbar 13 can be formed from ferritic stainless steel or austenitic stainless steel.

[0031] The first engaging portion 14 engages the terminal 12 with the busbar 13. The first engaging portion 14 allows the terminal 12 and busbar 13 to be removably engaged. The first engaging portion 14 can securely engage the terminal 12 and busbar 13 by clamping them together. Specifically, the first engaging portion 14 maintains the connection between the terminal 12 and busbar 13, and this connection can be released by removing the first engaging portion 14.

[0032] The first joint 14 may be, for example, a combination of a bolt and a nut. The first joint 14, which is a bolt and a nut, connects the terminal 12 and the busbar 13 by inserting the bolt through holes provided through the flat plate-shaped portion 22 and the flat plate-shaped portion 23 and then tightening the nut. The first joint 14 may be, for example, a mechanical joint tool other than the bolt and nut combination, such as a clamp.

[0033] The linear expansion coefficient of the first joining portion 14 is less than or equal to the linear expansion coefficient of the busbar 13. Furthermore, the linear expansion coefficient of the first joining portion 14 may be smaller than the linear expansion coefficient of the second joining portion 15. The linear expansion coefficient of the first joining portion 14 may be closer to the linear expansion coefficient of the terminal 12 than the linear expansion coefficient of the second joining portion 15. The linear expansion coefficient of the first joining portion 14 may be closer to the linear expansion coefficient of the terminal 12 than the linear expansion coefficient of the busbar 13.

[0034] The first joining portion 14 can be formed from a material having excellent corrosion resistance, heat resistance, and workability. The first joining portion 14 can be formed from a material containing a magnetic body. The material of the first joining portion 14 can be the same as or different from that of the terminal 12. Specifically, the first joining portion 14 can be formed from ferritic stainless steel.

[0035] The second joint 15 joins the external conductor to the busbar 13 at a position different from the terminal 12. For example, the position different from the terminal 12 is near the end opposite to the terminal 12 in the first direction. For example, the external conductor is a lead wire of a device such as a power converter that receives power output by the fuel cell stack 11.

[0036] The second joint 15 can detachably connect the bus bar 13 and the external conductor. In other words, the first joint 14 can maintain the connection between the bus bar 13 and the external conductor, and the connection can be released by removing the second joint 15.

[0037] In the structure in which the cylindrical portion 24 is formed with an external thread, the second engaging portion 15 may be a nut. The second engaging portion 15 may also be other mechanical engaging means other than a nut.

[0038] The second joining portion 15 may be formed of a material having high heat resistance and corrosion resistance and high strength. The second joining portion 15 may be formed of an oxidation-resistant metal. The linear expansion coefficient of the second joining portion 15 may be different from the linear expansion coefficient of the first joining portion 14. The linear expansion coefficient of the second joining portion 15 may be greater than the linear expansion coefficient of the first joining portion 14. The second joining portion 15 may be formed of austenitic stainless steel.

[0039] like Figure 1As shown, container 16 houses fuel cell stack 11, terminals 12, and first joint 14. Container 16 also houses a portion of bus bar 13. Container 16 may also house a portion of insulating portion 17, manifold 18, supply pipe 19, and reformer 20.

[0040] The insulating portion 17 can be provided on the busbar 13. The insulating portion 17 electrically insulates the busbar 13 from the container 16. Therefore, the insulating portion 17 can be provided throughout the entire area between the busbar 13 and the container 16. Specifically, the insulating portion 17 can be cylindrical and inserted through the cylindrical portion 24 of the busbar 13, thereby extending along the first direction. The length L1 of the insulating portion 17 in the first direction can be greater than 1 / 2 of the length L2 of the busbar 13 in the first direction and less than 3 / 4 of the length L2. The length of the busbar 13 is the length from the front end of the cylindrical portion to the front of the second joint 15.

[0041] The insulating portion 17 can be fixed to the container 16 in a state of penetrating the container 16. Specifically, the insulating portion 17 can be fixed by being fitted into a hole formed through the container 16.

[0042] The insulating portion 17 may be formed of an insulating material. Furthermore, the linear expansion coefficient of the insulating portion 17 may be smaller than the linear expansion coefficient of the busbar 13. Specifically, the insulating portion 17 may be formed of a ceramic material such as alumina or steatite.

[0043] The manifold 18 can fix one end of the fuel cell unit 21. Specifically, the manifold 18 can also fix the end of the fuel cell unit 21 on the first direction side. The manifold 18 can supply gas to each fuel cell unit 21. Specifically, the manifold 18 can supply fuel gas to each fuel cell unit 21. Specifically, as Figure 3 As shown, the manifold 18 may have a box portion 25 and a plate portion 26 .

[0044] The box portion 25 can define an internal space. The fuel cell units 21 can be inserted through one side of the box portion 25. The gas flowing from the supply pipe 19 into the internal space of the box portion 25 can be supplied to each fuel cell unit 21. Figure 4 As shown, the box portion 25 may be a rounded rectangle with the first direction being the long side when viewed in the second direction.

[0045] The plate portion 26 may protrude from the outer wall of the box portion 25. The plate portion 26 may be located on the side of the first direction where the supply pipe 19 is located. The plate portion 26 may protrude from a corner of the box portion 25 when viewed in the second direction. Specifically, the plate portion 26 may protrude from both corners of the box portion 25 when viewed in the second direction on the side of the first direction where the supply pipe 19 is located. A fan-shaped notch may be formed at one corner of the plate portion 26. The plate portion 26 may be perpendicular to the second direction.

[0046] The supply pipe 19 can supply gas to the manifold 18. Specifically, the internal space of the supply pipe 19 can be communicated with the internal space of the box portion 25 of the manifold 18. Figure 1 As shown, the supply pipe 19 may include a straight portion 27 extending in the second direction and a U-shaped curved portion 28 extending from the second direction end of the straight portion 27. The curved portion 28 may be connected to the bottom surface of the box portion 25 in the second direction.

[0047] The supply pipe 19 may be joined to the manifold 18 at a position different from the portion where it communicates with the tank portion 25. The supply pipe 19 may be joined to the manifold 18 at only a portion of the entire shaft circumference. More specifically, the supply pipe 19 may be joined to the outer edge of the plate portion 26 of the manifold 18. Even more specifically, the supply pipe 19 may be joined to a corner of the plate portion 26. In a configuration where a fan-shaped notch is formed at a corner of the plate portion 26, the supply pipe 19 may be joined within the notch.

[0048] The reformer 20 can reform light hydrocarbons such as city gas to generate hydrogen as fuel gas for the fuel cell 21. The reformer 20 can be located on the opposite side of the fuel cell stack 11 in the second direction. The fuel gas can be supplied to the reformer 20 via the supply pipe 19.

[0049] The fuel cell module 10 of this embodiment, having the above-described structure, includes: a fuel cell stack 11 having a plurality of stacked fuel cells 21; terminals 12 for outputting the power generated by the fuel cell stack 11; bus bars 13 connected to the terminals 12; first joints 14 for joining the terminals 12 to the bus bars 13; second joints 15 for joining an external conductor to the bus bars 13 at a position different from the terminals 12; and a container 16 for housing the fuel cell stack 11, the terminals 12, and the first joints 14, and for housing a portion of the bus bars 13. The linear expansion coefficient of the first joint 14 is less than that of the bus bars 13. The temperature within the container 16 during power generation is higher than during power generation. Therefore, the switching between power generation and power cessation causes temperature changes in the first joints 14 and bus bars 13. In response to such circumstances, the fuel cell module 10 having the above-described structure can reduce the gap between the first joints 14 and the bus bars 13 even when these temperatures change. In this manner, the fuel cell module 10 improves the joining between the terminals 12 and the bus bars 13 , which are a plurality of members constituting the electrical conductors for outputting electric power from the fuel cell stack 11 .

[0050] Furthermore, in the fuel cell module 10, the linear expansion coefficient of the first joint 14 is smaller than that of the second joint 15. The first joint 14 is closer to the fuel cell stack 11 than the second joint 15 and is therefore assumed to be exposed to a higher temperature environment than the second joint 15. On the other hand, the second joint 15 is assumed to be connected to external wiring, etc., and therefore may be subjected to tensile stress. In view of this assumption, the fuel cell module 10 having the above-described structure can further alleviate tensile stress because the second joint 15 is more easily deformed than the first joint 14.

[0051] Furthermore, in the fuel cell module 10, the linear expansion coefficient of the first joining portion 14 is closer to that of the terminal 12 than the linear expansion coefficient of the second joining portion 15. With this structure, the fuel cell module 10 minimizes the difference in expansion and contraction between the terminal 12 and the first joining portion 14 caused by temperature changes. Consequently, by reducing this difference in expansion and contraction, the fuel cell module 10 reduces the likelihood of peeling of the oxide film on the surface of the first joining portion 14 and other components, thereby reducing the increase in electrical resistance caused by peeling of the oxide film.

[0052] Furthermore, in the fuel cell module 10, the terminal 12 and the first joint 14 are formed of ferritic stainless steel. With this structure, the fuel cell module 10 can secure the first joint 14 by utilizing the magnetic force generated by the ferritic stainless steel during the joining process of the terminal 12 and the busbar 13 using the first joint 14. Therefore, the fuel cell module 10 facilitates the joining process. Furthermore, because the thermal expansion coefficient of ferritic stainless steel is relatively small, the fuel cell module 10 can reduce the gap between the terminal 12 and the first joint 14, which are closer to the fuel cell stack 11 and exposed to a high temperature environment.

[0053] Furthermore, in the fuel cell module 10, the second joint 15 is formed of austenitic stainless steel. With this structure, the fuel cell module 10 can alleviate tensile stress applied from external wiring, etc., due to the relatively large thermal expansion coefficient of austenitic stainless steel.

[0054] Furthermore, in the fuel cell module 10, the linear expansion coefficient of the first joint 14 is closer to that of the terminal 12 than the linear expansion coefficient of the busbar 13. The first joint 14 and the terminal 12, as a whole, are closer to the fuel cell stack 11 than the busbar 13 and are therefore exposed to a high-temperature environment. In such a situation, the fuel cell module 10 having the above-described structure can reduce the gap generated between the terminal 12 and the first joint 14, which are exposed to a high-temperature environment.

[0055] The fuel cell module 10 also includes an insulating portion 17 having a smaller linear expansion coefficient than that of the bus bar 13. This insulating portion 17 is provided along the first direction on the bus bar 13 and secured to the container 16, thereby electrically insulating the bus bar 13 from the container 16. Because the insulating portion 17 is in contact with the bus bar 13, it expands and contracts as the fuel cell stack 11 repeatedly generates and stops power. Consequently, this expansion and contraction of the insulating portion 17 applies stress to the container 16. In such situations, the fuel cell module 10 having the above-described structure can mitigate the stress applied to the container 16 because the insulating portion 17 has a smaller linear expansion coefficient than the bus bar 13. Furthermore, in the fuel cell module 10, the length L1 of the insulating portion 17 in the first direction exceeds ½ and is no greater than ¾ of the length L2 of the bus bar 13. With this structure, the fuel cell module 10 improves the reliability of the insulating portion 17 sandwiched between the bus bar 13 and the container 16 by defining a lower limit for the length L1 of the insulating portion 17 in the first direction. Therefore, the fuel cell module 10 can fully exert its stress relaxation effect on the container 16. Furthermore, by determining the upper limit of the length L1 of the insulating portion 17 in the first direction, the fuel cell module 10 can ensure a portion for connecting the bus bar 13 to the external conductor.

[0056] Furthermore, the fuel cell module 10 includes a manifold 18 and a supply pipe 19 for supplying gas to the manifold 18. The supply pipe 19 is joined to the manifold 18 only at a portion of its circumference. The supply pipe 19 is preferably supported at multiple locations within the container 16. Therefore, it is considered that the supply pipe 19 is supported at portions other than the supply portion of the manifold 18. Regarding support by the manifold 18, it is considered that the supply pipe 19 penetrates the manifold 18 and is joined by welding or the like over the entire circumferential area of the inner circumferential surface of the through hole of the manifold 18 and the outer circumferential surface of the supply pipe 19. On the other hand, the fuel cell module 10 having the above-described structure joins the supply pipe 19 to the manifold 18 only at a portion of its circumference. This allows for the stress concentration at the joint between the supply pipe 19 and the manifold 18 to be mitigated during temperature fluctuations caused by power generation and power cessation. Consequently, the fuel cell module 10 can reduce the likelihood of the supply pipe 19 peeling off from the manifold 18 by relieving this stress.

[0057] Furthermore, in the fuel cell module 10, the manifold 18 includes a box portion 25 and a plate portion 26, and the supply pipe 19 is joined to the outer edge of the plate portion 26. As described above, in a structure in which the supply pipe 19 penetrates the manifold 18 and is joined over the entire circumferential area of the inner circumferential surface of the through-hole of the manifold 18 and the outer circumferential surface of the supply pipe 19, the manifold 18 needs to have an area wider than the size of the through-hole, in addition to the area supporting the fuel cell stack 11 when viewed in the second direction. On the other hand, the fuel cell module 10 having the above-described structure does not need to have an area wider than the size of the through-hole, so the manifold 18 can be miniaturized when viewed in the second direction. Consequently, the fuel cell module 10 can be miniaturized as a whole.

[0058] Furthermore, in the fuel cell module 10, the supply tube 19 is joined to a corner of the plate portion 26. With this structure, the fuel cell module 10 can be arranged so that the joint between the supply tube 19 and the plate portion 26 is separated from the connection between the supply tube 19 and the tank portion 25 when viewed from the second direction. This increases the radius of curvature of the curved portion 28 of the supply tube 19, thereby reducing the bending stress applied to the curved portion 28.

[0059] Furthermore, in the fuel cell module 10, the linear expansion coefficient of the second bonding portion 15 is greater than that of the first bonding portion 14. Since the second bonding portion 15 is connected to an external conductor, tensile stress from this external conductor is frequently applied. In such situations, the fuel cell module 10 having the above structure can mitigate this tensile stress because the second bonding portion 15 easily deforms.

[0060] In one embodiment, (1) a fuel cell module includes:

[0061] A fuel cell stack having a plurality of fuel cell cells stacked on top of each other;

[0062] a terminal for outputting the power generated by the fuel cell stack;

[0063] a busbar connected to the terminal;

[0064] a first engaging portion engaging the terminal with the busbar;

[0065] a second joint portion that joins an outer conductor to the bus bar at a position different from that of the terminal; and

[0066] a container that houses the fuel cell stack, the terminal, and the first joint, and houses a portion of the bus bar;

[0067] The linear expansion coefficient of the first joining portion is equal to or less than the linear expansion coefficient of the generatrix.

[0068] (2) In the fuel cell module of (1) above,

[0069] The linear expansion coefficient of the first joining portion is smaller than the linear expansion coefficient of the second joining portion.

[0070] (3) In the fuel cell module of (1) or (2) above,

[0071] The linear expansion coefficient of the first joining portion is closer to the linear expansion coefficient of the terminal than the linear expansion coefficient of the second joining portion.

[0072] (4) In the fuel cell modules of (1) to (3) above,

[0073] The terminal and the first joint are formed of ferritic stainless steel.

[0074] The second joint portion is formed of austenitic stainless steel.

[0075] (5) In the fuel cell modules of (1) to (4) above,

[0076] The linear expansion coefficient of the first joint portion is closer to the linear expansion coefficient of the terminal than the linear expansion coefficient of the bus bar.

[0077] (6) The fuel cell modules of (1) to (5) above further include an insulating portion, wherein the insulating portion has a linear expansion coefficient smaller than that of the bus bar, is provided on the bus bar along a first direction in which the bus bar is separated from the fuel cell stack, and has a length L1 in the first direction that exceeds 1 / 2 of the length L2 of the bus bar and is less than 3 / 4 of the length L2 of the bus bar, and the insulating portion is fixed in a state where the insulating portion passes through the container and electrically insulates the bus bar from the container.

[0078] (7) The fuel cell module of (1) to (6) above further comprises:

[0079] a manifold that fixes one end of the fuel cell unit and supplies gas to the fuel cell unit; and

[0080] a supply pipe that supplies gas to the manifold,

[0081] The supply pipe is joined to the manifold at only a portion of the circumference of the supply pipe.

[0082] (8) In the fuel cell module of (7) above,

[0083] The manifold includes a box portion defining an internal space and allowing the supply pipe to communicate with the internal space, and a plate portion protruding from an outer wall surface of the box portion.

[0084] The supply pipe is joined to an outer edge of the plate portion.

[0085] (9) In the fuel cell module of (8) above,

[0086] The supply pipe is engaged with a corner portion of the plate portion.

[0087] In one embodiment, (10) a fuel cell device includes: the fuel cell module according to (1) to (9) above; and an auxiliary machine having an auxiliary function for operating the fuel cell module.

[0088] The drawings illustrating the embodiments of the present invention are schematic diagrams, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0089] While the embodiments of the present invention have been described based on the accompanying drawings and examples, it should be noted that those skilled in the art are capable of various modifications and variations based on the present invention. Therefore, it should be noted that such modifications and variations are within the scope of the present invention. For example, the functions included in each structural component, etc., can be rearranged in a logically consistent manner, and multiple structural components, etc., can be combined into one or divided.

[0090] All of the constituent elements described in the present invention and / or all of the disclosed methods or all of the steps of the process can be combined in any combination, except for the mutually exclusive combination of these features. In addition, the features described in the present invention can be replaced with alternative features that function for the same purpose, equivalent purpose, or similar purpose, as long as they are not explicitly denied. Therefore, as long as they are not explicitly denied, the disclosed features are each merely an example of a series of identical or equivalent features.

[0091] Furthermore, the embodiments of the present invention are not limited to any specific structure in the above-mentioned embodiments. The embodiments of the present invention can be expanded to all new features described in the present invention, or their combinations, or all new methods or processing steps described in the present invention, or their combinations.

[0092] In the present invention, the descriptions such as "first" and "second" are identifiers used to distinguish the structures. The structures distinguished by the descriptions such as "first" and "second" in the present invention can exchange the numbers of the structures. For example, the first joint can exchange the identifiers "first" and "second" with the second joint. The exchange of identifiers is carried out simultaneously. After the exchange of identifiers, the structures are distinguished. The identifiers can be deleted. The structures with deleted identifiers are distinguished by the figure marks. The order of the structures cannot be interpreted based solely on the descriptions of identifiers such as "first" and "second" in the present invention, nor can the existence of identifiers with smaller numbers be used.

[0093] Description of Reference Numerals

[0094] 10 Fuel Cell Module

[0095] 11 Fuel cell stack

[0096] 12 terminals

[0097] 13 busbar

[0098] 14 First joint

[0099] 15 Second joint

[0100] 16 containers

[0101] 17 Insulation

[0102] 18 Manifold

[0103] 19 Supply pipe

[0104] 20 Modifier

[0105] 21 fuel cell monomer

[0106] 22 Flat part

[0107] 23 Flat part

[0108] 24 cylindrical part

[0109] 25 Box Department

[0110] 26 Board

[0111] 27 Straight line

[0112] 28 curved portion.

Claims

1. A fuel cell module, wherein: The fuel cell module comprises: A fuel cell stack having a plurality of fuel cell cells stacked on top of each other; a terminal for outputting the power generated by the fuel cell stack; a busbar connected to the terminal; a first engaging portion engaging the terminal with the busbar; a second joining portion that joins the outer conductor to the bus bar at a position different from that of the terminal; as well as a container that houses the fuel cell stack, the terminal, and the first joint, and houses a portion of the bus bar; The linear expansion coefficient of the first joining portion is equal to or less than the linear expansion coefficient of the generatrix.

2. The fuel cell module according to claim 1, wherein: The linear expansion coefficient of the first joining portion is smaller than the linear expansion coefficient of the second joining portion.

3. The fuel cell module according to claim 1 or 2, wherein: The linear expansion coefficient of the first joining portion is closer to the linear expansion coefficient of the terminal than the linear expansion coefficient of the second joining portion.

4. The fuel cell module according to any one of claims 1 to 3, wherein: The terminal and the first joint are formed of ferritic stainless steel. The second joint portion is formed of austenitic stainless steel.

5. The fuel cell module according to any one of claims 1 to 4, wherein: The linear expansion coefficient of the first joint portion is closer to the linear expansion coefficient of the terminal than the linear expansion coefficient of the bus bar.

6. The fuel cell module according to any one of claims 1 to 5, wherein: The fuel cell module also has an insulating portion, which has a linear expansion coefficient smaller than that of the bus bar, is arranged on the bus bar along a first direction in which the bus bar is separated from the fuel cell monomer stack, and has a length in the first direction that exceeds 1 / 2 of the length of the bus bar and is less than 3 / 4 of the length of the bus bar, and the insulating portion is fixed in a state of penetrating the container and electrically insulates the bus bar from the container.

7. The fuel cell module according to any one of claims 1 to 6, wherein: The fuel cell module further comprises: a manifold that fixes one end of the fuel cell unit and supplies gas to the fuel cell unit; and a supply pipe that supplies gas to the manifold, The supply pipe is joined to the manifold only over a portion of the supply pipe in the circumferential direction.

8. The fuel cell module according to claim 7, wherein: The manifold includes a box portion defining an internal space and allowing the supply pipe to communicate with the internal space, and a plate portion protruding from an outer wall surface of the box portion. The supply pipe is joined to an outer edge of the plate portion.

9. The fuel cell module according to claim 8, wherein: The supply pipe is engaged with a corner portion of the plate portion.

10. A fuel cell device, wherein: The fuel cell device comprises: the fuel cell module according to any one of claims 1 to 9; and an auxiliary machine having an auxiliary function for operating the fuel cell module.

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