Fuel cell stack and fuel cell unit

Abstract

To provide a fuel cell stack and a fuel cell unit capable of adjusting the number of laminated fuel cells without changing the configuration of a first current collector and a second current collector.SOLUTION: In a fuel cell unit 10, when a fuel cell stack 20 is viewed from the stacking direction A, a first terminal 33 protrudes outside a cell stack 21 in the horizontal direction X from the first side F3. When the fuel cell stack 20 is viewed from the stacking direction A, a second terminal 43 protrudes outside the cell stack 21 in the vertical direction Z from the upper side F1. The first terminal 33 and the second terminal 43 are arranged at circumferentially separated positions so as not to interfere with each other.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a fuel cell stack and a fuel cell unit. [Background technology]

[0002] As an example of a fuel cell unit including a fuel cell stack, a fuel cell system is disclosed in Patent Document 1. The fuel cell system in Patent Document 1 includes a stack serving as a fuel cell stack. The stack includes a laminate in which a large number of cells serving as fuel cell units are stacked, a positive current collector at one end of the laminate in the stacking direction, and a negative current collector at the other end of the laminate in the stacking direction. Each of the pair of current collectors includes an upper terminal and a lower terminal as terminals for extracting current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-145225 A Summary of the Invention [Problem to be solved by the invention]

[0004] Fuel cell stacks are available in a variety of specifications to suit the installation site and requirements. One of the fuel cell stack specifications is a specification in which the number of stacked fuel cells is reduced, but this specification reduces the dimensions of the fuel cell stack in the stacking direction. If the gap between a pair of current collectors is narrowed in the stacking direction and the distance between the terminals of a pair of current collectors is also narrowed in the stacking direction, when connecting a component to one terminal, the other terminal gets in the way, making it difficult to connect the terminals and components. In addition, to prevent short circuits, the position of the terminals of the current collectors needs to be changed, and the shape of the current collectors needs to be changed to suit the multiple fuel cell stack specifications. [Means for solving the problem]

[0005] A fuel cell stack for solving the above problems includes a cell stack in which a plurality of fuel cells are stacked in a stacking direction, a first current collector arranged at one end of the cell stack in the stacking direction, and a second current collector arranged at the other end of the cell stack in the stacking direction, wherein the cell stack has an upper side located at an upper end in a vertical direction when the cell stack is viewed from the stacking direction, a lower side located at a lower end in the vertical direction, a first side side located at a first end in a horizontal direction, and a second side side located at a second end in the horizontal direction, and wherein the upper side, the first side side, the lower side, and the second side side are connected to each other when viewed from the stacking direction. The gist of the invention is that the direction is the circumferential direction of the cell stack, the first current collector has a first current collecting portion stacked on the cell stack and a first terminal protruding from an edge of the first current collecting portion and to which a first electrical wiring is connected, and the second current collector has a second current collecting portion stacked on the cell stack and a second terminal protruding from an edge of the second current collecting portion and to which a second electrical wiring is connected, and when viewing the fuel cell stack from the stacking direction, at least one of the first terminal and the second terminal protrudes from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack and is positioned at positions spaced apart in the circumferential direction so as not to interfere with each other.

[0006] According to this, when performing the work of connecting a first electrical wiring to a first terminal, or the work of connecting a second electrical wiring to a second terminal, there is no interference between the first electrical wiring and the second terminal, or between the second electrical wiring and the first terminal, making it easy to connect the terminals and electrical wiring.

[0007] Furthermore, the dimension of the cell stack in the stacking direction may be reduced by adjusting the number of stacked fuel cells. When the dimension of the cell stack in the stacking direction is reduced, the distance in the stacking direction between the first current collector and the second current collector becomes narrower. Because the first terminal and the second terminal are positioned so as not to interfere with each other, even if the distance becomes narrower, it is possible to prevent a short circuit between the first terminal and the second terminal, and in turn a short circuit between the first electrical wiring and the second electrical wiring. Therefore, by setting the positions of the first terminal and the second terminal, it is possible to adjust the number of stacked fuel cell cells without changing the configuration of the first current collector and the second current collector.

[0008] Regarding a fuel cell stack, when viewing the fuel cell stack from the stacking direction, the first terminal may protrude from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack, and the second terminal may protrude from the top edge in the vertical direction to the outside of the cell stack.

[0009] According to this, when the fuel cell stack is viewed from the stacking direction, the first terminal and the second terminal protrude from different sides, making it easy to separate the first terminal and the second terminal. This makes it easy to connect the first electrical wiring to the first terminal, or the second electrical wiring to the second terminal. Furthermore, it is possible to prevent a short circuit between the first electrical wiring and the second electrical wiring.

[0010] Regarding a fuel cell stack, when the fuel cell stack is viewed from the stacking direction, both the first terminal and the second terminal may protrude from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack.

[0011] This makes it easy to connect the first electrical wire to the first terminal and the second electrical wire to the second terminal. A fuel cell unit for solving the above problems includes a fuel cell stack, a power distribution section electrically connected to the fuel cell stack, and electrical wiring connecting the fuel cell stack and the power distribution section, the power distribution section being a fuel cell unit arranged below the fuel cell stack in a vertical direction, the fuel cell stack including a cell stack in which a plurality of fuel cells are stacked in a stacking direction, a first current collector arranged at one end of the cell stack in the stacking direction, and a second current collector arranged at the other end of the cell stack in the stacking direction, the cell stack including an upper edge located at an upper end in the vertical direction when viewed from the stacking direction, a lower edge located at a lower end in the vertical direction, a first side edge located at a first end in a horizontal direction, and a second side edge located at a second end in the horizontal direction, and a direction in which the upper edge, the second side edge, the lower edge, and the first side edge are connected is defined as a circumferential direction of the cell stack when viewed from the stacking direction. the first current collector has a first current collecting portion stacked on the cell stack and a first terminal protruding from an edge of the first current collecting portion, the second current collector has a second current collecting portion stacked on the cell stack and a second terminal protruding from an edge of the second current collecting portion, when the fuel cell stack is viewed from the stacking direction, at least the first terminal protrudes from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack, when the fuel cell stack is viewed from the stacking direction, the first terminal and the second terminal are arranged at positions spaced apart in the circumferential direction so as not to interfere with each other, when the fuel cell stack is viewed from the stacking direction, the electrical wiring has a first terminal connection portion, an electric wire extending from the first terminal connection portion, and a second terminal connection portion of the electric wire opposite to the first terminal connection portion, and the first terminal connection portion of the electric wire is connected to the first terminal, and the second terminal connection portion is electrically connected to the power distribution unit with the electric wire hanging down from the first terminal.

[0012] According to this, when connecting the electric wiring to the first terminal, there is no interference between the electric wiring and the second terminal, and the work of connecting the terminal and the electric wiring can be easily performed. Furthermore, the dimension of the cell stack in the stacking direction may be reduced by adjusting the number of stacked fuel cells. When the dimension of the cell stack in the stacking direction is reduced, the gap in the stacking direction between the first current collector and the second current collector becomes narrower. Because the first terminal and the second terminal are positioned so that they do not interfere with each other, a short circuit between the first terminal and the second terminal can be prevented even if the gap becomes narrower. Therefore, by setting the positions of the first terminal and the second terminal, it is possible to adjust the number of stacked fuel cell cells without changing the configuration of the first current collector and the second current collector.

[0013] In addition, in the fuel cell unit, the power distribution unit is disposed below the fuel cell stack, so that the power distribution unit is located at the end of the electric wire hanging down from the first terminal, facilitating the connection between the electric wiring and the power distribution unit.

[0014] With respect to a fuel cell unit, when a direction perpendicular to the vertical direction and the horizontal direction is defined as the depth direction of the fuel cell unit, in a planar view of the fuel cell unit in the vertical direction, the fuel cell stack may be positioned near a first end face in the depth direction of the fuel cell unit, and the first terminal may be positioned along the first end face.

[0015] According to this, when connecting electrical wiring to the first terminal, the first terminal can be easily accessed from outside the fuel cell unit, and the work of connecting the first terminal to the first terminal connecting portion and connecting the electrical wiring can be easily performed.

[0016] In the fuel cell unit, the first terminal connection portion may be a round terminal, and the first terminal and the first terminal connection portion may be connected by screwing a bolt and a nut together. This makes it easy to insert the bolt into the first terminal connection portion, and facilitates the task of connecting the first terminal and the first terminal connection portion using the bolt and nut.

[0017] Regarding a fuel cell unit, when viewing the fuel cell stack from the stacking direction, the second terminal may protrude from the upper edge in the vertical direction to the outside of the cell stack, and the second terminal may have a base end plate protruding upward from the second collecting portion, a tip plate intersecting the base end plate, a nut joined to the underside of the tip plate, and a cover covering the female thread of the nut from below.

[0018] With this, even if foreign matter is generated when the bolt is screwed into the nut, the foreign matter can be received by the cover and prevented from falling into the cell stack. Effect of the Invention

[0019] According to the present invention, it is possible to adjust the number of stacked fuel cells without changing the configurations of the first current collector and the second current collector. [Brief description of the drawings]

[0020] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a perspective view showing a fuel cell stack. [Figure 4] FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a first terminal and a second terminal. [Figure 6] FIG. [Figure 7] FIG. 4 is an exploded perspective view showing a first terminal and a first electrical wiring. [Figure 8] FIG. 4 is an exploded perspective view showing a second terminal, a bus bar, and a second electrical wiring. [Figure 9] FIG. 11 is a perspective view showing a fuel cell stack according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a fuel cell stack and a fuel cell unit according to an embodiment will be described with reference to FIGS. 1 and 2, the fuel cell unit 10 includes a frame 11, a hydrogen tank 13, an air compressor 14, a capacitor 15, a heat exchanger 16, a power distribution section 17, and a fuel cell stack 20. The fuel cell unit 10 also includes a first electrical wiring 18, a second electrical wiring 19, and a bus bar 48 that electrically connect the fuel cell stack 20 and the power distribution section 17.

[0022] The frame 11 has a bottom plate 11a, a plurality of pillars 11b standing upright from the bottom plate 11a, and a support plate 11c supported by the plurality of pillars 11b. Assuming that the fuel cell unit 10 is placed on a horizontal plane, the direction of gravity is indicated by the Z axis, and the directions along the horizontal plane are indicated by the X axis and the Y axis. The X axis, Y axis, and Z axis are perpendicular to each other. In the following description, the direction parallel to the Z axis is also referred to as the vertical direction Z, and the direction parallel to the X axis is also referred to as the horizontal direction X. The horizontal direction X is parallel to the long side direction of the bottom plate 11a. The direction parallel to the Y axis is also referred to as the depth direction Y. The depth direction Y is parallel to the short side direction of the bottom plate 11a. Therefore, the depth direction Y is a direction perpendicular to both the horizontal direction X and the vertical direction Z. The direction in which the pillars 11b rise from the bottom plate 11a is parallel to the vertical direction Z.

[0023] A hydrogen tank 13, a heat exchanger 16, and a power distribution unit 17 are arranged on the bottom plate 11a. The hydrogen tank 13 and the power distribution unit 17 are aligned in the depth direction Y. The hydrogen tank 13 and the heat exchanger 16 are aligned in the horizontal direction X. A fuel cell stack 20, an air compressor 14, and a capacitor 15 are arranged on the support plate 11c. The fuel cell stack 20 and the air compressor 14 are aligned in the horizontal direction X, and the fuel cell stack 20 and the capacitor 15 are aligned in the depth direction Y. The power distribution unit 17 is arranged below the fuel cell stack 20 in the vertical direction Z.

[0024] A first terminal 33 serving as a positive electrode terminal of the fuel cell stack 20 and a positive electrode terminal 17 a of the power distribution unit 17 are electrically connected by a first electrical wiring 18 . The first electric wiring 18 has a first electric wire 18a as an electric wire, a first terminal connection part 18b at one end of the first electric wire 18a, and a second terminal connection part 18c opposite the first terminal connection part 18b in the first electric wire 18a. The first terminal 33 and the first terminal connection part 18b are connected, and the positive electrode terminal 17a and the second terminal connection part 18c are connected. The first terminal connection part 18b and the second terminal connection part 18c are round terminals.

[0025] The second terminal 43, which is the negative electrode terminal of the fuel cell stack 20, and the negative electrode terminal 17b of the power distribution unit 17 are electrically connected via the second electrical wiring 19 and the bus bar 48. Therefore, the bus bar 48 is also an electrical wiring connected to the second terminal 43.

[0026] The bus bar 48 is an elongated metal plate. The second electric wiring 19 has a second electric wire 19a, a first terminal connection portion 19b at one end of the second electric wire 19a, and a second terminal connection portion 19c opposite to the first terminal connection portion 19b in the second electric wire 19a. The first terminal connection portion 19b and the second terminal connection portion 19c are round terminals.

[0027] Second terminal 43 is connected to a first end of bus bar 48. A second end of bus bar 48 is connected to first terminal connection portion 19b, and negative terminal 17b is connected to second terminal connection portion 19c.

[0028] The fuel cell stack 20 is used, for example, as a power source for a fuel cell vehicle that runs on hydrogen and oxygen as fuel. The fuel cell stack 20 generates direct current electrical energy (direct current power) by reacting hydrogen gas supplied from the hydrogen tank 13 with oxygen in the air supplied from the air compressor 14. The air compressor 14 compresses the air and supplies it to the fuel cell stack 20.

[0029] The capacitor 15 stores the electric power generated by the fuel cell stack 20. The heat exchanger 16 exchanges heat between a heat exchange medium that has exchanged heat with the fuel cell stack 20 and the outside air. Cooling water is used as the heat exchange medium, but other media may also be used. The power distribution unit 17 includes components that control the power generation of the fuel cell stack 20.

[0030] As shown in Figures 2, 3 and 4, the fuel cell stack 20 includes a cell stack 21, a first current collector 31, a second current collector 41, a first cover plate 22, a second cover plate 23, a fastening member 24, an insulator 25, and a stack manifold 26.

[0031] The cell stack 21 is a laminate formed by stacking a plurality of fuel cells S. The direction in which the fuel cells S are stacked is referred to as the “stacking direction A.” Thus, the cell stack 21 is formed by stacking a plurality of fuel cells S in the stacking direction A.

[0032] Viewing the members from the stacking direction A is simply referred to as a "front view." The fuel cell S is an electricity storage module that extracts energy from a chemical reaction between hydrogen and oxygen as electric power. The fuel cell S is a rectangular plate-shaped member.

[0033] The stacking direction A coincides with the depth direction Y of the fuel cell unit 10. The cell stack 21 has a first stacking end face 21a at a first end in the stacking direction A and a second stacking end face 21b at a second end in the stacking direction A.

[0034] The fuel cell stack 20 has an upper surface H1 and a lower surface H2 formed by stacking all of the fuel cell units S in a stacking direction A. The fuel cell stack 20 also has a first side surface H3 and a second side surface H4 formed by stacking all of the fuel cell units S in the stacking direction A.

[0035] 6, in a front view of the cell stack 21 seen from the stacking direction A, the cell stack 21 has an upper side F1 located at the upper end in the vertical direction Z, a lower side F2 located at the lower end in the vertical direction Z, a first side F3 located at a first end in the horizontal direction X, and a second side F4 located at a second end in the horizontal direction X. The upper side F1 of the cell stack 21 is a side that runs along an upper surface H1 of the cell stack 21, and the lower side F2 of the cell stack 21 is a side that runs along a lower surface H2 of the cell stack 21. The first side F3 of the cell stack 21 is a side that runs along a first side surface H3 of the cell stack 21, and the second side F4 of the cell stack 21 is a side that runs along a second side surface H4 of the cell stack 21.

[0036] The direction in which the top side F1, the second side F4, the bottom side F2, and the first side F3 of the cell stack 21 are connected is defined as the circumferential direction of the cell stack 21. The first current collector 31 is disposed on a first stacking end surface 21a, which is one end of the cell stack 21 in the stacking direction A. The first current collector 31 is for extracting the electric power generated by the fuel cell S. Various conductors can be used for the first current collector 31.

[0037] As shown in Figs. 2, 3 and 4, the first current collector 31 includes a first current collecting portion 32 and a first terminal 33. The first current collecting portion 32 is a rectangular plate. The first current collecting portion 32 includes two short edge portions 32a at both ends in the horizontal direction X. The first current collecting portion 32 is stacked on the first stacking end surface 21a of the cell stack 21. The long side direction of the first current collecting portion 32 coincides with the long side direction of the fuel cell S. The plate thickness direction of the first current collecting portion 32 coincides with the stacking direction A. The first current collecting portion 32 is arranged so as to include the cell stack 21 in its internal region when viewed from the front in the stacking direction A.

[0038] The first terminal 33 is a terminal connected to the first electric wiring 18. The first terminal 33 protrudes from a short edge portion 32a which is one edge portion of the first current collecting portion 32. The first terminal 33 has a first terminal plate 34, a first nut 35 joined to the first terminal plate 34, and a first cover 36 integrated with the first nut 35.

[0039] As shown in FIG. 5, the first terminal plate 34 protrudes from one short edge portion 32a in the horizontal direction X. The first terminal plate 34 has a first through hole 34a penetrating the first terminal plate 34 in the plate thickness direction. The first nut 35 has one end face in the axial direction joined to the first terminal plate 34. The female thread 35a of the first nut 35 overlaps with the first through hole 34a. The first nut 35 has a press-in hole 35b recessed from the end face opposite to the end face joined to the first terminal plate 34. The press-in hole 35b has a larger diameter than the female thread 35a. The first nut 35 has the press-in hole 35b formed therein, but the female thread 35a is long enough to screw the first bolt 37 in.

[0040] The first cover 36 is made of synthetic resin. The first cover 36 has a cylindrical portion 36a and a lid 36b that closes one end of the cylindrical portion 36a. The outer diameter of the cylindrical portion 36a is the same as or slightly larger than the inner diameter of the press-fit hole 35b. The end of the cylindrical portion 36a opposite the lid 36b is press-fitted into the press-fit hole 35b. This press-fitting makes the first cover 36 integrated with the first nut 35. The lid 36b of the first cover 36 closes the female thread 35a from the side opposite the first through hole 34a.

[0041] 2, 3, and 4, the second current collector 41 is disposed on the second stacking end surface 21b, which is the other end of the cell stack 21 in the stacking direction A. The second current collector 41 is for extracting the electric power generated by the fuel cell S. Various conductors can be used for the second current collector 41. The second current collector 41 includes a second current collecting portion 42 and a second terminal 43.

[0042] The second current collecting part 42 is in the shape of a rectangular plate. The second current collecting part 42 has long edge parts 42a at both ends in the vertical direction Z. The second current collecting part 42 is stacked on the second stacking end surface 21b of the cell stack 21. The long side direction of the second current collecting part 42 coincides with the long side direction of the fuel cell S. The plate thickness direction of the second current collecting part 42 coincides with the stacking direction A. The second current collecting part 42 is arranged so that the cell stack 21 is included in its internal region when viewed from the front from the stacking direction A. The second current collecting part 42 has flow passage holes (not shown) so that fuel gas and coolant can pass between the cell stack 21 and the stack manifold 26.

[0043] The second terminal 43 is a terminal that is connected to the second electric wiring 19 together with the bus bar 48. The second terminal 43 protrudes from a long edge portion 42a that is one edge portion of the second current collecting portion 42. The second terminal 43 has a second terminal plate 44, a second nut 45 joined to the second terminal plate 44, and a second cover 46 integrated with the second nut 45.

[0044] The second terminal plate 44 has a base end plate 44a protruding upward from one long edge portion 42a along the vertical direction Z, and a tip plate 44b intersecting the base end plate 44a. The tip plate 44b protrudes in the stacking direction A from the base end plate 44a toward the first current collector 31.

[0045] As shown in FIG. 5, the tip plate 44b of the second terminal plate 44 has a second through hole 44c penetrating the tip plate 44b in the plate thickness direction. The second nut 45 is joined to the lower surface of the tip plate 44b. The second through hole 44c opens on the upper surface of the tip plate 44b. The female thread 45a of the second nut 45 overlaps with the second through hole 44c. The second nut 45 has a press-fit hole 45b recessed from one end face. Although the press-fit hole 45b is formed in the second nut 45, the female thread 45a is long enough to sufficiently screw in the second bolt 47.

[0046] The second cover 46 is made of synthetic resin. The second cover 46 has a cylindrical portion 46a and a lid 46b that closes one side of the cylindrical portion 46a. The outer diameter of the cylindrical portion 46a is the same as or slightly larger than the inner diameter of the press-fit hole 45b. The end of the cylindrical portion 46a opposite to the lid 46b is press-fitted into the press-fit hole 45b. By this press-fitting, the second cover 46 is integrated with the second nut 45. The lid 46b of the second cover 46 closes the female thread 45a from the side opposite to the second through hole 44c, that is, from below. The second terminal 43 having the above configuration has a base end plate 44a that protrudes upward from the second current collecting portion 42, a tip plate 44b that intersects with the base end plate 44a, a second nut 45 joined to the lower surface of the tip plate 44b, and a second cover 46 that closes the female thread 45a of the second nut 45 from below.

[0047] As shown in FIGS. 2, 3 and 4, the first cover plate 22 and the second cover plate 23 are members for applying pressure to the cell stack 21 in the stacking direction A. As shown in FIG. The first cover plate 22 is in the shape of a rectangular plate. The short sides of the first cover plate 22 are longer than the short sides of the first current collecting portion 32. The long sides of the first cover plate 22 are longer than the long sides of the first current collecting portion 32. The first cover plate 22 is provided on the first stacking end surface 21a of the cell stack 21 with the first current collector 31 sandwiched therebetween. Therefore, the first current collector 31 is provided between the first cover plate 22 and the cell stack 21.

[0048] The second cover plate 23 has a rectangular plate shape. The long sides of the second cover plate 23 are longer than the long sides of the second current collecting portion 42. The short sides of the second cover plate 23 are longer than the short sides of the second current collecting portion 42. The second cover plate 23 is provided on the second stacking end surface 21b of the cell stack 21 with the second current collector 41 in between.

[0049] The fastening member 24 fastens the first cover plate 22 and the second cover plate 23. The fastening member 24 is composed of a bolt 24a and a nut 24b. The bolt 24a is inserted through the first cover plate 22 and the second cover plate 23. The nut 24b is attached to the bolt 24a so as to pressurize the cell stack 21 against the first cover plate 22 and the second cover plate 23. The fastening member 24 presses and fixes members such as the cell stack 21 provided between the first cover plate 22 and the second cover plate 23 in the stacking direction A.

[0050] The insulator 25 is an insulating member for insulating the first current collector 31 from the first cover plate 22. The insulator 25 is provided on the first stacking end surface 21a of the cell stack 21 with the first current collector 31 sandwiched therebetween.

[0051] The stack manifold is a piping component for supplying hydrogen, oxygen, and cooling water to the cell stack 21. The stack manifold is provided between the second current collector 41 and the second cover plate .

[0052] The fuel cell stack 20 is formed by stacking in a stacking direction A, in that order, a second cover plate 23, a stack manifold 26, a second current collector 41, a cell stack 21, a first current collector 31, an insulator 25, and a first cover plate 22.

[0053] As shown in FIG. 6, in a front view of the first stacking end surface 21a of the fuel cell stack 20 seen from the stacking direction A, the first terminal 33 protrudes from the first side edge F3 of the cell stack 21 in the horizontal direction X to the outside of the cell stack 21. In the following description, the front view of the first stacking end surface 21a of the fuel cell stack 20 seen from the stacking direction A will simply be referred to as a "front view of the fuel cell stack 20." In the front view of the fuel cell stack 20, the first through hole 34a of the first terminal plate 34 opens outward along the depth direction Y. In the front view of the fuel cell stack 20, a first nut 35 is disposed on the back side of the first terminal plate 34 in the depth direction Y.

[0054] In a front view of the fuel cell stack 20, the second terminal 43 protrudes from the upper side F1 of the cell stack 21 to the outside of the cell stack 21 in the vertical direction Z. The second terminal 43 is located closer to the second side F4 than the center of the upper side F1 in the horizontal direction X. The base end plate 44a of the second terminal 43 protrudes upward from the upper side F1 in the vertical direction Z. The tip plate 44b bends relative to the base end plate 44a and protrudes in the stacking direction A. The tip plate 44b faces the upper surface H1 in the vertical direction Z. There is a gap between the tip plate 44b and the upper surface H1 in the vertical direction Z. The second through hole 44c of the second terminal plate 44 opens upward. Therefore, the second nut 45 is disposed closer to the cell stack 21 than the second terminal plate 44. The second cover 46 also covers the female thread 45a of the second nut 45 from below.

[0055] In a front view of the fuel cell stack 20, the first terminal 33 and the second terminal 43 protrude from different sides of the cell stack 21. In a front view of the fuel cell stack 20, the first terminal 33 and the second terminal 43 are disposed at positions spaced apart in the circumferential direction of the cell stack 21 so as not to interfere with each other.

[0056] In a front view of the fuel cell stack 20, the first terminal 33 is disposed diagonally below the second terminal 43. The first terminal 33 is separated from the second terminal 43 in the horizontal direction X by a length that is approximately half the length of the long side of the cell stack 21.

[0057] 7, the first terminal 33 is connected to the first terminal connection portion 18b of the first electrical wiring 18 by a first bolt 37. The first bolt 37 is inserted into the first terminal connection portion 18b from the outside of the fuel cell unit 10, and into the first through hole 34a. The first bolt 37 that passes through the first through hole 34a is screwed into the female thread 35a of the first nut 35.

[0058] 8, a first end of a bus bar 48 is connected to the second terminal 43 by a second bolt 47. The second bolt 47 is inserted into a first hole 48a of the bus bar 48 from the upper side of the fuel cell unit 10, and is inserted into the second through hole 44c. The second bolt 47 that passes through the second through hole 44c is screwed into the female thread 45a of the second nut 45.

[0059] A second end of the bus bar 48 is disposed at a position facing the first side surface H3 of the cell stack 21. A first terminal connection portion 19b of the second electrical wiring 19 is connected to the second end of the bus bar 48 by a third bolt 49. The third bolt 49 is inserted into the second hole 48b of the bus bar 48 from the left side of the fuel cell unit 10. The third bolt 49 is screwed into a nut 51.

[0060] 6, first electric wire 18a of first electric wiring 18 hangs down from first terminal 33. With first electric wire 18a hanging down from first terminal 33, second terminal connection portion 18c is electrically connected to power distribution unit 17. In other words, first electric wire 18a hangs down from first terminal 33 toward power distribution unit 17. Second terminal connection portion 18c of first electric wiring 18 is connected to positive terminal 17a of power distribution unit 17.

[0061] Second electric wire 19a of second electric wiring 19 hangs down from a second end of bus bar 48. Second electric wire 19a hangs down from the second end of bus bar 48 toward power distribution unit 17. Second terminal connection portion 19c of second electric wiring 19 is connected to negative terminal 17b of power distribution unit 17.

[0062] 2, in a plan view of the fuel cell unit 10 seen from the vertical direction Z, the fuel cell stack 20 is disposed closer to a first end face in the depth direction Y of the fuel cell unit 10, and the capacitor 15 is disposed closer to a second end face in the depth direction Y. In a plan view of the fuel cell unit 10 seen from the vertical direction Z, the first current collector 31 is disposed closer to the first end face in the depth direction Y than the second current collector 41. The first terminal 33 is disposed along the first end face of the fuel cell unit 10, and is disposed closer to the first end face than the second terminal 43.

[0063] The effects of this embodiment will be described below. (1) The fuel cell stack 20 is available in a variety of specifications depending on where the fuel cell stack 20 is to be installed. One of the specifications of the fuel cell stack 20 is a specification in which the number of stacked fuel cell cells S is reduced. In this specification, the dimension of the fuel cell stack 20 in the stacking direction A is reduced. At the same time, the distance between the first current collector 31 and the second current collector 41 in the stacking direction A is also reduced.

[0064] In a front view of the fuel cell stack 20, the first terminal 33 protrudes from the first side edge F3 to the outside of the cell stack 21 in the horizontal direction X, and the second terminal 43 protrudes from the top edge F1 to the outside of the cell stack 21 in the vertical direction Z. Therefore, even if the gap between the first current collector 31 and the second current collector 41 in the stacking direction A becomes narrower, the first terminal 33 and the second terminal 43 do not overlap in the stacking direction A and do not interfere with each other. As a result, even if the gap between the first current collector 31 and the second current collector 41 in the stacking direction A becomes narrower, a short circuit between the first terminal 33 and the second terminal 43, and therefore a short circuit between the first electrical wiring 18 and the second electrical wiring 19, can be prevented.

[0065] Therefore, by setting the positions of the first terminal 33 and the second terminal 43, it is possible to adjust the number of stacked fuel cell cells S without changing the configurations of the first current collector 31 and the second current collector 41. Also, it is possible to avoid interference between the first terminal 33 and the second terminal 43 without changing the structures of the first current collector 31 and the second current collector 41. In other words, even if the first current collector 31 and the second current collector 41 are made common, it is possible to accommodate changes in the specifications of the fuel cell stack 20.

[0066] (2) In a front view of the fuel cell stack 20, the first terminal 33 protrudes from the first side F3 in the horizontal direction X to the outside of the cell stack 21, and the second terminal 43 protrudes from the top side F1 in the vertical direction Z to the outside of the cell stack 21. Therefore, the first terminal 33 and the second terminal 43 are disposed at positions spaced apart in the circumferential direction so as not to interfere with each other in the fuel cell stack 20. Therefore, when performing either one of the work of connecting the first electrical wiring 18 to the first terminal 33 and the work of connecting the bus bar 48 to the second terminal 43, the other terminal does not get in the way of the work. Therefore, the work of connecting the first electrical wiring 18 to the first terminal 33 or the work of connecting the bus bar 48 to the second terminal 43 can be easily performed.

[0067] (3) In a front view of the fuel cell stack 20, if both the first terminal 33 and the second terminal 43 protrude from the first side edge F3, the first terminal 33 and the second terminal 43 are close to each other in the stacking direction A, increasing the risk of a short circuit between the first electrical wiring 18 and the second electrical wiring 19. However, in a front view of the fuel cell stack 20, the first terminal 33 protrudes from the first side edge F3 to the outside of the cell stack 21 in the horizontal direction X, and the second terminal 43 protrudes from the top edge F1 to the outside of the cell stack 21 in the vertical direction Z. This makes it possible to prevent a short circuit between the first terminal 33 and the second terminal 43.

[0068] (4) In a front view of the fuel cell stack 20, the first terminal 33 protrudes from the first side F3 in the horizontal direction X to the outside of the cell stack 21. When the first electrical wiring 18 is connected to the first terminal 33, the first electric wire 18a can be allowed to hang down from the first terminal 33. In the fuel cell unit 10, the power distribution unit 17 is disposed below the fuel cell stack 20. Therefore, the power distribution unit 17 is located at the tip of the first electric wire 18a hanging down from the first terminal 33, making it easy to connect the first electrical wiring 18 to the power distribution unit 17.

[0069] (5) In a front view of the fuel cell stack 20, the base end plate 44a of the second terminal 43 protrudes above the upper side F1, and the tip plate 44b is bent relative to the base end plate 44a so as to face the upper surface H1. The tip plate 44b has a second through hole 44c that opens upward, and a second nut 45 is joined to the lower surface of the tip plate 44b. This allows the second bolt 47 to be inserted through the second through hole 44c from above the fuel cell stack 20 and screwed into the second nut 45. This makes it easy to connect the bus bar 48 to the second current collector 41 using the second bolt 47.

[0070] (6) The second cover 46 of the second current collector 41 closes the female thread 45a of the second nut 45 from below. For this reason, even if a foreign object is generated when the second bolt 47 is screwed into the second nut 45, the second cover 46 can prevent the foreign object from falling onto the upper surface H1 of the cell stack 21.

[0071] (7) A first nut 35 is joined to the first terminal plate 34 of the first terminal 33. Therefore, it is easier to screw in the first bolt 37 than when the first nut 35 is separate from the first terminal plate 34. Similarly, a second nut 45 is joined to the second terminal plate 44 of the second terminal 43. Therefore, it is easier to screw in the second bolt 47 than when the second nut 45 is separate from the second terminal plate 44.

[0072] (8) In a plan view of the fuel cell unit 10 viewed in the vertical direction Z, the fuel cell stack 20 is disposed toward a first end face in the depth direction Y of the fuel cell unit 10. The first terminal 33 is disposed along the first end face of the fuel cell unit 10. For this reason, when connecting the first electrical wiring 18 to the first terminal 33, the first terminal 33 is easily accessible, making it easy to connect the first electrical wiring 18 to the first terminal 33.

[0073] (9) The first terminal connection portion 18b of the first electric wiring 18 is a round terminal, and the first terminal 33 and the first terminal connection portion 18b are connected by screwing the first bolt 37 and the first nut 35 together. This makes it easy to insert the first bolt 37 into the first terminal connection portion 18b, and makes it easy to connect the first terminal 33 and the first electric wiring 18 using the first bolt 37 and the first nut 35. In particular, when the first bolt 37 is moved in the depth direction Y and screwed into the first nut 35, the first bolt 37 can be moved while being inserted into the first terminal connection portion 18b, making it easy to connect the first terminal connection portion 18b to the first terminal 33.

[0074] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs. The first cover 36 of the first terminal 33 may be omitted, and the second cover 46 of the second terminal 43 may be omitted.

[0075] A first bolt 37 may be joined to the first terminal plate 34 of the first terminal 33 instead of the first nut 35. When connecting the first terminal connection portion 18b of the first electrical wiring 18 to the first terminal 33, the first bolt 37 protruding from the first terminal plate 34 is inserted into the first terminal connection portion 18b, and then the first nut 35 is screwed onto the first bolt 37.

[0076] Instead of the second nut 45, a second bolt 47 may be joined to the second terminal plate 44 of the second terminal 43. It is preferable that the second bolt 47 protrudes from the upper surface of the tip plate 44b. When connecting the second terminal 43 to the bus bar 48, the second bolt 47 protruding from the second terminal plate 44 is inserted into the first hole 48a of the bus bar 48, and then the second nut 45 is screwed onto the second bolt 47.

[0077] The first terminal 33 and the first electric wire 18 may be connected by welding. Similarly, the second terminal 43 and the bus bar 48 may be connected by welding. In a plan view of the fuel cell unit 10 in the vertical direction Z, the first terminal 33 may be disposed on the opposite side to the first end face of the fuel cell unit 10. In this case, the second current collector 41 of the fuel cell stack 20 is disposed closer to the first end face in the depth direction Y, and the first current collector 31 is disposed further back in the depth direction Y than the second current collector 41.

[0078] When viewed from the front of the fuel cell stack 20, the first terminal 33 may protrude from the second side edge F4, and the second terminal 43 may protrude from the top edge F1. As shown in Fig. 9, in a front view of the fuel cell stack 20, the first terminal 33 may protrude from the first side edge F3, and the second terminal 43 may also protrude from the first side edge F3. In other words, when viewing the fuel cell stack 20 from the stacking direction A, both the first terminal 33 and the second terminal 43 may protrude from the first side edge F3 or the second side edge F4 in the horizontal direction X to the outside of the cell stack 21. In this case, it is preferable to separate the first terminal 33 and the second terminal 43 as far apart as possible in the vertical direction Z. This configuration makes it easy to connect the first electrical wiring 18 to the first terminal 33 and the second electrical wiring 19 to the second terminal 43.

[0079] In a front view of the fuel cell stack 20, the first terminal 33 may protrude from the first side F3 or the second side F4, and the second terminal 43 may protrude from the bottom side F2. At least one of the first terminal connection portion 18b of the first electric wire 18 and the first terminal connection portion 19b of the second electric wire 19 may be changed from a round terminal to a Y terminal.

[0080] The nut 24b may be omitted. In that case, a female thread is formed in the first cover plate 22, and the bolt 24a is screwed in so as to pressurize the cell stack 21 against the first cover plate 22 and the second cover plate 23. In other words, the fastening member 24 is composed of the bolt 24a and the female thread formed in the first cover plate 22. [Explanation of symbols]

[0081] A...stacking direction, F1...upper edge, F2...lower edge, F3...first side edge, F4...second side edge, S...fuel cell, X...horizontal direction, Y...depth direction, Z...vertical direction, 10...fuel cell unit, 17...power distribution section, 18...first electrical wiring, 18a...first electric wire, 18b...first terminal connection section, 18c...second terminal connection section, 19...second electrical wiring, 20...fuel cell stack, 21...cell stack, 31...first current collector, 32...first current collector, 32a...short edge, 33...first terminal, 35...first nut, 37...first bolt, 41...second current collector, 42...second current collector, 42a...long edge, 43...second terminal, 44a...base end plate, 44b...tip plate, 45...second nut, 46...second cover.

Claims

1. a cell stack in which a plurality of fuel cells are stacked in a stacking direction; a first current collector disposed at one end of the cell stack in the stacking direction; a second current collector disposed at the other end of the cell stack in the stacking direction, The cell stack includes: an upper edge located at an upper end in a vertical direction perpendicular to the stacking direction when the cell stack is viewed from the stacking direction, a lower edge located at a lower end in the vertical direction, a first side edge located at a first end in a horizontal direction perpendicular to the stacking direction and the vertical direction, and a second side edge located at a second end in the horizontal direction, a direction in which the upper side, the first side, the lower side, and the second side are connected as viewed from the stacking direction is defined as a circumferential direction of the cell stack; the first current collector has a first current collecting portion that is stacked on the cell stack, and a first terminal that protrudes from an edge of the first current collecting portion and is connected to a first electrical wiring; the second current collector has a second current collecting portion that is stacked on the cell stack, and a second terminal that protrudes from an edge of the second current collecting portion and to which a second electrical wiring is connected; a fuel cell stack characterized in that, when viewing the fuel cell stack from the stacking direction, one of the first terminal and the second terminal protrudes from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack, a tip of one of the first terminal and the second terminal extends in the horizontal direction, the other of the first terminal and the second terminal protrudes from the top edge or the bottom edge to the outside of the cell stack in the vertical direction, and a tip of the other of the first terminal and the second terminal is bent toward the cell stack.

2. 2. The fuel cell stack according to claim 1, wherein, when viewing the fuel cell stack from the stacking direction, the first terminal protrudes from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack, and the second terminal protrudes from the top edge in the vertical direction to the outside of the cell stack.

3. A fuel cell stack; a power distribution section electrically connected to the fuel cell stack; and electrical wiring connecting the fuel cell stack and the power distribution unit, the power distribution unit is a fuel cell unit disposed vertically below the fuel cell stack, The fuel cell stack comprises: a cell stack in which a plurality of fuel cells are stacked in a stacking direction; a first current collector disposed at one end of the cell stack in the stacking direction; a second current collector disposed at the other end of the cell stack in the stacking direction, The cell stack includes: an upper edge located at an upper end in the vertical direction perpendicular to the stacking direction when the cell stack is viewed from the stacking direction, a lower edge located at a lower end in the vertical direction, a first side edge located at a first end in a horizontal direction perpendicular to the stacking direction and the vertical direction, and a second side edge located at a second end in the horizontal direction, a direction in which the upper side, the second side, the lower side, and the first side are connected as viewed from the stacking direction is defined as a circumferential direction of the cell stack; the first current collector has a first current collecting portion stacked in the cell stack and a first terminal protruding from an edge of the first current collecting portion, the second current collector has a second current collecting portion stacked on the cell stack and a second terminal protruding from an edge of the second current collecting portion, when viewing the fuel cell stack from the stacking direction, the first terminal protrudes from the first side edge or the second side edge in the horizontal direction to the outside of the cell stack, and a tip of the first terminal extends in the horizontal direction, the second terminal protrudes from the upper side or the lower side in the vertical direction to the outside of the cell stack, and a tip of the second terminal is bent toward the cell stack, the electrical wiring includes a first terminal connection portion, an electric wire extending from the first terminal connection portion, and a second terminal connection portion of the electric wire opposite the first terminal connection portion; A fuel cell unit characterized in that the electrical wiring is electrically connected to the power distribution section with the first terminal connection portion connected to the first terminal and the second terminal connection portion with the electric wire hanging down from the first terminal.

4. 4. The fuel cell unit described in claim 3, wherein, when the direction perpendicular to the vertical direction and the horizontal direction is defined as the depth direction of the fuel cell unit, in a planar view of the fuel cell unit in the vertical direction, the fuel cell stack is positioned toward a first end face in the depth direction of the fuel cell unit, and the first terminal is positioned along the first end face.

5. 5. The fuel cell unit according to claim 3, wherein the first terminal connection portion is a round terminal, and the first terminal and the first terminal connection portion are connected by screwing together a bolt and a nut.

6. When the fuel cell stack is viewed from the stacking direction, the second terminal protrudes from the upper side in the vertical direction to an outside of the cell stack, A fuel cell unit as described in any one of claims 3 to 5, wherein the second terminal has a base end plate protruding upward from the second collecting portion, a tip plate intersecting the base end plate, a nut joined to the underside of the tip plate, and a cover covering the female thread of the nut from below.

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