Fuel cell stack and fuel cell unit provided with plurality of said fuel cell stacks

Abstract

A first end sheet (2) and a second end sheet (6) respectively have: left protrusions (21, 61) which are positioned at the left of a cell laminate (4) and which protrude leftward; left engagement holes (2g1, 6g1) which are provided to the left protrusions (21, 61) and with which a first fastening bolt (10a1) is engaged; right protrusions (22, 62) which are positioned at the right of the cell laminate (4) and which protrude rightward; and right engagement holes (2g2, 6g2) which are provided to the right protrusions (22, 62) and with which a second fastening bolt (10a2) is engaged. The left protrusions (21, 61) and the right protrusions (22, 62) are provided at different positions in the vertical direction.

Description

Fuel cell stack and fuel cell unit including multiple fuel cell stacks

[0001] The present disclosure relates to a fuel cell stack and a fuel cell unit including a plurality of such stacks.

[0002] Patent Document 1 discloses a fuel cell in which multiple fuel cell units are stacked together. In each fuel cell unit, a rectangular membrane electrode assembly, which has a pair of electrodes on either side of an electrolyte membrane and a picture-frame-shaped resin frame on its periphery, and rectangular separators are stacked together.

[0003] JP 2012-227020 A

[0004] A fuel cell unit can be constructed by arranging multiple fuel cell stacks. The present disclosure aims to provide a technology suitable for reducing the space required for a fuel cell unit while ensuring the reliability of the fuel cell stack.

[0005] The present disclosure provides an electrical wiring board comprising: a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a plurality of fastening bolts; the first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate are stacked in this order in a stacking direction of the cell stack; the plurality of fastening bolts connect the first end plate and the second end plate; and the plurality of fastening bolts include a first fastening bolt and a second fastening bolt; and when a direction perpendicular to the stacking direction is defined as a left-right direction, each of the first end plate and the second end plate has: a left protruding portion located to the left of the cell stack and protruding leftward; a left engagement hole provided in the left protruding portion and with which the first fastening bolt engages; a right protruding portion located to the right of the cell stack and protruding rightward; and a right engagement hole provided in the right protruding portion and with which the second fastening bolt engages. When a direction perpendicular to the stacking direction and the left-right direction is defined as a vertical direction, the left protrusion and the right protrusion are provided at different positions in the vertical direction.

[0006] In another aspect, the present disclosure provides a fuel cell stack comprising: a plurality of fuel cell stacks, each of the plurality of fuel cell stacks comprising a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a fastening bolt, the first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate being stacked in this order in a stacking direction of the cell stack, and the fastening bolt connecting the first end plate and the second end plate, the plurality of fuel cell stacks including a first fuel cell stack and a second fuel cell stack, wherein, when a direction perpendicular to the stacking direction is defined as a left-right direction, the first fuel cell stack and the second fuel cell stack are arranged adjacent to each other in the left-right direction such that the first fuel cell stack is located to the left of the second fuel cell stack, and each of the first end plate and the second end plate of the first fuel cell stack comprises: a right protrusion located to the right of the cell stack of the first fuel cell stack and protruding rightward, a right engagement hole provided in the right protrusion, with which the fastening bolt of the first fuel cell stack engages; and a left engagement hole provided in the left protrusion, with which the fastening bolt of the second fuel cell stack engages; wherein each of the first end plate and the second end plate of the second fuel cell stack has a left protrusion located to the left of the cell stack of the second fuel cell stack and protruding to the left; and a left engagement hole provided in the left protrusion, with which the fastening bolt of the second fuel cell stack engages; and when the direction perpendicular to the stacking direction and the left-right direction is defined as the up-down direction, the right protrusion and the left protrusion are provided at different positions in the up-down direction.

[0007] The technology according to the present disclosure is suitable for reducing the space required for a fuel cell unit while ensuring the reliability of the fuel cell stack.

[0008] 7 is a perspective view of a fuel cell unit according to the second embodiment; 8 is a perspective view of a fuel cell stack according to the first embodiment; 9 is a front view of a fuel cell stack according to the first embodiment; 10 is a rear view of a fuel cell stack according to the first embodiment; 11 is a cross-sectional view of a fuel cell stack according to the first embodiment; 12 is a cross-sectional view of a fuel cell stack according to a first modified example; 13 is a front view of a fuel cell unit according to the second embodiment;

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted.

[0010] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0011] First Embodiment Hereinafter, a first embodiment will be described with reference to FIGS. 1 to 5. FIG.

[0012] [1-1. Configuration] Fig. 1 is an exploded perspective view of a fuel cell stack 1 according to a first embodiment. Fig. 2 is a perspective view of the fuel cell stack 1. Fig. 3 is a front view of the fuel cell stack 1. Fig. 4 is a rear view of the fuel cell stack 1. Fig. 5 is a partial cross-sectional view of the fuel cell stack 1.

[0013] The fuel cell stack 1 includes a first end plate 2, a first current collector plate 3, a cell stack 4, a second current collector plate 5, a second end plate 6, six fastening bolts 10a1 to 10a6, and a heat insulator 7. The cell stack 4 includes a plurality of stacked cells 4a. The six fastening bolts 10a1 to 10a6 connect the first end plate 2 and the second end plate 6.

[0014] In the first embodiment, for convenience, the stacking direction in which the cells 4a are stacked in the cell stack 4 is defined as the front-rear direction, the direction perpendicular to the front-rear direction is defined as the left-right direction, and the direction perpendicular to the front-rear direction and the left-right direction is defined as the up-down direction. Note that in the first embodiment, the left-right direction is a direction parallel to the mounting surface ps1 on which the fuel cell stack 1 is mounted. In the first embodiment, the mounting surface ps1 of the fuel cell stack 1 is formed by the bottom surfaces of two legs 2j provided on the lower surface 2b of the first end plate 2 and the bottom surfaces of two legs 6j provided on the lower surface 6b of the second end plate 6.

[0015] In the first embodiment, the front-rear direction is sometimes referred to as the X direction, the left-right direction is sometimes referred to as the Y direction, and the up-down direction is sometimes referred to as the Z direction.

[0016] The X, Y, and Z directions are perpendicular to one another. In Fig. 1 and other figures, the arrows of the X, Y, and Z directions point to the positive sides of the X, Y, and Z directions.

[0017] In the first embodiment, "orthogonal" does not necessarily mean that the angle between the two directions is exactly 90°. For example, the angle between the two directions is considered to be orthogonal when it is between 80° and 100°. Furthermore, "parallel" does not necessarily mean that the two directions are completely aligned. For example, the angle between the two directions is considered to be parallel when it is between 0° and 20°.

[0018] Furthermore, in the first embodiment, directions and components may be described using terms such as "top," "bottom," "side," "front," "rear," "left," and "right." Specifically, the positive Z direction may be referred to as the upward direction, the negative Z direction may be referred to as the downward direction, the positive X direction may be referred to as the forward direction, the negative X direction may be referred to as the rearward direction, the positive Y direction may be referred to as the rightward direction, and the negative Y direction may be referred to as the leftward direction.

[0019] In the following description, "left" and "right" refer to the positional relationship when viewed along the front-to-back direction in the X direction. The left-to-right direction is reversed between Figure 3 and Figure 4.

[0020] The names of the directions are used for convenience in explaining the relative positional relationships of the components, and are not intended to limit the installation posture of the fuel cell stack 1.

[0021] The first end plate 2, the first current collector plate 3, the cell stack 4, the second current collector plate 5, and the second end plate 6 are stacked in this order in the X direction (see FIG. 2).

[0022] (First end plate 2) The outer shape of the first end plate 2 is approximately rectangular when viewed from the X direction. The first end plate 2 has an upper surface 2a, a lower surface 2b, a front surface 2e, a rear surface 2f, a left side surface 2c, and a right side surface 2d. The first end plate 2 is insulating. This insulating property prevents the electricity generated by the cell stack 4 from leaking to the outer shell of the fuel cell stack 1. In this specification, "insulating" refers to electrical insulation. The first end plate 2 is made of resin. Specifically, the first end plate 2 is made of phenolic resin. The upper surface 2a and the lower surface 2b are surfaces of the first end plate 2 that face each other in the vertical direction (Z). A first handle portion 2i (handle) is provided on the upper surface 2a. The longitudinal direction of the first handle portion 2i extends in the Y direction. The first handle 2i of the first end plate 2 is used when installing or removing the fuel cell stack 1. Two legs 2j are provided on both the left and right ends of the lower surface 2b. The two legs 2j protrude downward.

[0023] The front surface 2e and the rear surface 2f are surfaces of the first end plate 2 that face each other in the front-to-rear direction (X). The front surface 2e faces the outside of the fuel cell stack 1. The rear surface 2f faces the first current collector plate 3. Six communication holes 2h1 to 2h6 are provided in the first end plate 2. The six communication holes 2h1 to 2h6 penetrate the first end plate 2 in the front-to-rear direction (X). Specifically, the six communication holes 2h1 to 2h6 extend from the front surface 2e to the rear surface 2f. The three communication holes 2h1 to 2h3 are arranged side by side in the left-to-right direction (Y direction) near the center of the upper surface 2a. The three communication holes 2h4 to 2h6 are arranged side by side in the left-to-right direction (Y direction) near the center of the lower surface 2b.

[0024] Three pipes 8a1 to 8a3 of the inlet side manifold 8 are arranged in the communication holes 2h1 to 2h3 on the top surface 2a. Hydrogen gas is supplied from the outside to the first pipe 8a1. Oxygen gas is supplied from the outside to the second pipe 8a2. Cooling water is supplied from the outside to the third pipe 8a3. These mixed gases are supplied to the cell stack 4.

[0025] Three pipes 9a1 to 9a3 of the outlet manifold 9 are arranged in the communication holes 2h4 to 2h6 on the lower surface 2b. Hydrogen gas is discharged to the outside from the first pipe 9a1. Oxygen gas is discharged to the outside from the second pipe 9a2. Cooling water is discharged to the outside from the third pipe 9a3.

[0026] A left protrusion 21 protruding leftward (negative side in the Y direction) is provided on the left side surface 2c of the first end plate 2. A right protrusion 22 protruding rightward (positive side in the Y direction) is provided on the right side surface 2d of the first end plate 2. Six engagement holes 2g1 to 2g6 are provided in the first end plate 2, penetrating the first end plate 2 in the front-to-rear direction (X).

[0027] Specifically, the left protruding portion 21 is located to the left of the reference surface 19 in the left-right direction (Y) and is defined by a left protruding surface 23 (see FIG. 3 ). The right protruding portion 22 is located to the right of the reference surface 20 in the left-right direction (Y) and is defined by a right protruding surface 24. The reference surface 19, the reference surface 20, the left protruding surface 23, and the right protruding surface 24 will be described later.

[0028] Specifically, the left protrusion 21 extends from the front surface 2e to the rear surface 2f, the right protrusion 22 extends from the front surface 2e to the rear surface 2f, and the six engagement holes 2g1 to 2g6 extend from the front surface 2e to the rear surface 2f.

[0029] The engagement holes 2g1 to 2g6 have the following positional relationship when viewed from the front side (positive side in the X direction).

[0030] With respect to the left-right direction (Y), the engagement hole 2g3 is located to the left (negative side in the Y direction) of the engagement hole 2g4, and the engagement hole 2g5 is located to the left (negative side in the Y direction) of the engagement hole 2g6.

[0031] With respect to the vertical direction (Z), - engagement hole 2g3 is located above engagement holes 2g1 and 2g2, - engagement hole 2g4 is located above engagement holes 2g1 and 2g2, - engagement hole 2g5 is located below engagement holes 2g1 and 2g2, - engagement hole 2g6 is located below engagement holes 2g1 and 2g2.

[0032] Specifically, two engagement holes 2g3 and 2g4 are provided on the left and right sides of the upper surface 2a, and two engagement holes 2g5 and 2g6 are provided on the left and right legs 2j of the lower surface 2b.

[0033] The engagement hole 2g is provided in the left protruding portion 21. The engagement hole 2g is provided in the right protruding portion 22. Specifically, the engagement hole 2g extends from the front surface 2e to the rear surface 2f. The engagement hole 2g extends from the front surface 2e to the rear surface 2f.

[0034] Note that "the engagement hole 2g is provided in the left protruding portion 21" means that the engagement hole 2g is provided in at least a part of the left protruding portion 21 when viewed from the front direction (positive side in the X direction). "The engagement hole 2g is provided in the right protruding portion 22" means that the engagement hole 2g is provided in at least a part of the right protruding portion 22 when viewed from the front direction (positive side in the X direction).

[0035] The left side surface 2c and the right side surface 2d are surfaces of the first end plate 2 that face each other in the left-right direction (Y).

[0036] The left side surface 2c includes a flat reference surface 19 and a left protruding surface 23 that protrudes to the left (negative Y direction) of the reference surface 19. The reference surface 19 is parallel to the up-down direction (Z) and the front-rear direction (X). The left protruding surface 23 is curved convexly to the left (negative Y direction) of the reference surface 19. The left protruding surface 23 is the outer surface of the left protrusion 21. In the left-right direction (Y), at least a portion of the engagement hole 2g1 is located to the left (negative Y direction) of a plane that includes the reference surface 19 (see FIG. 3). Specifically, in the left-right direction (Y), the engagement hole 2g1 is located so as to straddle the plane that includes the reference surface 19.

[0037] The right side surface 2d includes a flat reference surface 20 and a right protruding surface 24 that protrudes to the right (positive side in the Y direction) beyond the reference surface 20. The reference surface 20 is parallel to the up-down direction (Z) and the front-rear direction (X). The right protruding surface 24 is curved convexly to the right (positive side in the Y direction) relative to the reference surface 20. The right protruding surface 24 is the outer surface of the right protrusion 22. In the left-right direction (Y), at least a portion of the engagement hole 2g2 is located to the right (positive side in the Y direction) of a plane that includes the reference surface 20 (see FIG. 3). Specifically, in the left-right direction (Y), the engagement hole 2g2 is located so as to straddle a plane that includes the reference surface 20.

[0038] The left protrusion 21 and the right protrusion 22 are located at different positions in the vertical direction (Z) (see FIG. 3 ). The vertical position of the left protrusion 21 is defined as a left protrusion position P1. Specifically, when the mounting surface ps1 of the fuel cell stack 1 is used as a reference, the left protrusion position P1 is located at the same height as the center of the engagement hole 2g1 of the left protrusion 21. The vertical position of the right protrusion 22 is defined as a right protrusion position P2. Specifically, the right protrusion position P2 is located at the same height as the mounting surface ps1 of the fuel cell stack 1 to the center of the engagement hole 2g2 of the right protrusion 22. At this time, on the left side surface 2c of the first end plate 2, the reference plane 19, which is at the same height as the right protrusion position P2 relative to the left protrusion surface 23 located at the left protrusion position P1, is located to the right (positive side in the Y direction). Furthermore, on the right side surface 2d, the reference surface 20, which is at the same height as the left protruding position P1, is located on the left side (negative side in the Y direction) compared to the right protruding surface 24, which is at the right protruding position P2. The engagement holes 2g1 and 2g2 are provided at different positions in the up-down direction (Z).

[0039] The deviation in the vertical direction (Z) between the center positions of engagement holes 2g1 and 2g2 is, for example, 15 mm or more and 40 mm or less. For example, the vertical direction (Z) center position of engagement hole 2g1 belongs to the central region when the vertical direction (Z) length between the center positions of engagement holes 2g3 and 2g5 is equally divided into thirds (specifically, five). For example, the vertical direction (Z) center position of engagement hole 2g2 belongs to the central region when the vertical direction (Z) length between the center positions of engagement holes 2g4 and 2g6 is equally divided into thirds (specifically, five).

[0040] (First current collecting plate 3) The first current collecting plate 3 has a substantially rectangular outer shape. A connection terminal 3a is formed on the upper end of the first current collecting plate 3. The first current collecting plate 3 is made of an aluminum material that is silver-plated. Aluminum material makes it easy to obtain conductivity and strength. Silver plating makes it easy to obtain corrosion resistance and low contact resistance. Brass or the like may also be used as the material. Gold plating or the like may also be used as the plating.

[0041] (Cell stack 4 and insulation material 7) The cell stack 4 is formed by stacking multiple cells 4a in the front-to-back direction (X). The cell stack 4 is covered with insulation material 7. The insulation material 7 is flexible in the thickness direction of the insulation material 7. Specifically, the insulation material 7 is formed by combining a first insulation panel 7a and a second insulation panel 7b. Each of the first insulation panel 7a and the second insulation panel 7b is formed by connecting three panels. The three panels are formed by connecting the long sides of flat plates having rectangular main surfaces.

[0042] (Second current collecting plate 5) The outer shape of the second current collecting plate 5 is approximately rectangular. A connection terminal 5a is formed on the upper end of the second current collecting plate 5. The second current collecting plate 5 is made of an aluminum material that is silver-plated. Aluminum material makes it easy to obtain conductivity and strength. Silver plating makes it easy to obtain corrosion resistance and low contact resistance. Brass or the like may also be used as the material. Gold plating or the like may also be used as the plating.

[0043] (Second End Plate 6) The outer shape of the second end plate 6 is approximately rectangular when viewed in the X direction. The second end plate 6 has an upper surface 6a, a lower surface 6b, a front surface 6e, a rear surface 6f, a left side surface 6c, and a right side surface 6d. The second end plate 6 is insulating. This insulating property prevents the power generated by the cell stack 4 from leaking to the outer casing of the fuel cell stack 1. The second end plate 6 is made of resin. Specifically, the second end plate 6 is made of phenolic resin. The upper surface 6a and the lower surface 6b are opposite surfaces of the second end plate 6 in the up-down direction (Z). A second handle portion 6i (handle) is provided on the upper surface 6a. The longitudinal direction of the second handle portion 6i extends in the Y direction. The second handle portion 6i of the second end plate 6 is used when installing or removing the fuel cell stack 1. Two legs 6j are provided on both the left and right ends of the lower surface 6b, and the two legs 6j protrude downward.

[0044] The front surface 6e and the rear surface 6f are surfaces of the second end plate 6 that face each other in the front-to-rear direction (X). The front surface 6e faces the second current collector plate 5 side of the second end plate 6. The rear surface 6f faces the outside of the fuel cell stack 1. The second end plate 6 has thirteen recesses 6h that open to its front surface 6e. Thirteen elastic members 10c are disposed inside the thirteen recesses 6h. Specifically, the elastic members are fastening springs. The thirteen recesses 6h are arranged in three rows along the vertical direction (Z). The thirteen elastic members 10c are disposed inside the thirteen recesses 6h. Because the front surface 6e faces the second current collector plate 5 side of the second end plate 6, the repulsive force of the thirteen elastic members 10c applies pressure from the second end plate 6 to the current collector plate 5 in the forward direction (positive side of the X direction). In addition to springs, rubber, elastomers, etc. may also be included in the elastic member.

[0045] A left protrusion 61 protruding leftward (negative side in the Y direction) is provided on the left side surface 6c of the second end plate 6. A right protrusion 62 protruding rightward (positive side in the Y direction) is provided on the right side surface 6d of the second end plate 6. Six engagement holes 6g1 to 6g6 are provided in the second end plate 6, penetrating the second end plate 6 in the front-to-rear direction (X).

[0046] Specifically, the left protruding portion 61 is located to the left of the reference surface 59 in the left-right direction (Y) and is defined by a left protruding surface 63 (see FIG. 4). The right protruding portion 62 is located to the right of the reference surface 60 in the left-right direction (Y) and is defined by a right protruding surface 64. The reference surfaces 59, 60, the left protruding surface 63, and the right protruding surface 64 will be described later.

[0047] Specifically, the left protrusion 61 extends from the front surface 6e to the rear surface 6f, the right protrusion 62 extends from the front surface 6e to the rear surface 6f, and the six engagement holes 6g1 to 6g6 extend from the front surface 6e to the rear surface 6f.

[0048] The engagement holes 6g1 to 2g6 have the following positional relationship when viewed from the front side (positive side in the X direction).

[0049] With respect to the left-right direction (Y), the engagement hole 6g3 is located to the left (negative side in the Y direction) of the engagement hole 6g4, and the engagement hole 6g5 is located to the left (negative side in the Y direction) of the engagement hole 6g6.

[0050] With respect to the vertical direction (Z), - engagement hole 6g3 is located above engagement holes 6g1 and 6g2, - engagement hole 6g4 is located above engagement holes 6g1 and 6g2, - engagement hole 6g5 is located below engagement holes 6g1 and 6g2, - engagement hole 6g6 is located below engagement holes 6g1 and 6g2.

[0051] Specifically, two engagement holes 6g3 and 6g4 are provided on the left and right sides of the upper surface 6a, and two engagement holes 6g5 and 6g6 are provided on the left and right legs 6j of the lower surface 6b.

[0052] The engagement hole 6g1 is provided in the left protrusion 61. The engagement hole 6g2 is provided in the right protrusion 62. Specifically, the engagement hole 6g1 extends from the front surface 6e to the rear surface 6f. The engagement hole 6g2 extends from the front surface 6e to the rear surface 6f.

[0053] Note that "the engagement hole 6g1 is provided in the left protruding portion 61" means that the engagement hole 6g1 is provided in at least a part of the left protruding portion 61 when viewed from the front direction (positive side in the X direction). "The engagement hole 6g2 is provided in the right protruding portion 62" means that the engagement hole 6g2 is provided in at least a part of the right protruding portion 62 when viewed from the front direction (positive side in the X direction).

[0054] The left side surface 6c and the right side surface 6d are surfaces of the second end plate 6 that face each other in the left-right direction (Y).

[0055] The left side surface 6c includes a flat reference surface 59 and a left protruding surface 63 that protrudes to the left (negative side in the Y direction) of the reference surface 59. The reference surface 59 is parallel to the up-down direction (Z) and the front-rear direction (X). The left protruding surface 63 is curved convexly to the left (negative side in the Y direction) with respect to the reference surface 59. The left protruding surface 63 is the outer surface of the left protrusion 61. In the left-right direction (Y), at least a portion of the engagement hole 6g1 is located to the left (negative side in the Y direction) of a plane that includes the reference surface 59 (see FIG. 4). Specifically, in the left-right direction (Y), the engagement hole 6g1 is located so as to straddle a plane that includes the reference surface 59.

[0056] The right side surface 6d includes a flat reference surface 60 and a right protruding surface 64 that protrudes to the right (positive side in the Y direction) beyond the reference surface 60. The reference surface 60 is parallel to the up-down direction (Z) and the front-rear direction (X). The right protruding surface 64 is curved convexly to the right (positive side in the Y direction) relative to the reference surface 60. The right protruding surface 64 is the outer surface of the right protrusion 62. In the left-right direction (Y), at least a portion of the engagement hole 6g2 is located to the right (positive side in the Y direction) of a plane that includes the reference surface 60 (see FIG. 4). Specifically, in the left-right direction (Y), the engagement hole 6g2 is located so as to straddle a plane that includes the reference surface 60.

[0057] The left protrusion 61 and the right protrusion 62 are located at different positions in the vertical direction (Z) (see FIG. 4 ). The vertical position of the left protrusion 61 is defined as a left protrusion position P3. Specifically, when the mounting surface ps1 of the fuel cell stack 1 is used as a reference, the left protrusion position P3 is located at the same height as the center of the engagement hole 6g1 of the left protrusion 61. The vertical position of the right protrusion 62 is defined as a right protrusion position P4. Specifically, the right protrusion position P4 is located at the same height as the center of the engagement hole 6g2 of the right protrusion 42 from the mounting surface ps1 of the fuel cell stack 1. At this time, on the left side surface 6c of the second end plate 6, the reference plane 59, which is at the same height as the right protrusion position P4 relative to the left protrusion surface 63 located at the left protrusion position P3, is located to the right (positive side in the Y direction). Furthermore, on the right side surface 6d, the reference surface 60, which is at the same height as the left protruding position P3, is located on the left side (negative side in the Y direction) compared to the right protruding surface 64, which is at the right protruding position P4. The engagement holes 6g1 and 6g2 are provided at different positions in the up-down direction (Z).

[0058] The deviation in the vertical direction (Z) between the center positions of the engagement holes 6g1 and 6g2 is, for example, 15 mm to 40 mm. For example, the vertical direction (Z) center position of the engagement hole 6g1 belongs to the central region when the vertical direction (Z) length between the center positions of the engagement holes 6g3 and 6g5 is equally divided into thirds (specifically, five). For example, the vertical direction (Z) center position of the engagement hole 6g2 belongs to the central region when the vertical direction (Z) length between the center positions of the engagement holes 6g4 and 6g6 is equally divided into thirds (specifically, five).

[0059] (Fastening bolts 10a) The fastening bolts 10a1 to 10a6 are used to fasten the first end plate 2 and the second end plate 6 in the front-to-rear direction (X). The fastening bolts 10a1 to 10a6 are in the following positional relationship when viewed from the front (positive side in the X direction).

[0060] With respect to the left-right direction (Y), fastening bolt 10a1 is located to the left (negative side in the Y direction) of fastening bolt 10a2, fastening bolt 10a3 is located to the left (negative side in the Y direction) of fastening bolt 10a4, and fastening bolt 10a5 is located to the left (negative side in the Y direction) of fastening bolt 10a6.

[0061] With respect to the vertical direction (Z), fastening bolt 10a3 is located above fastening bolts 10a1 and 10a2, fastening bolt 10a4 is located above fastening bolts 10a1 and 10a2, fastening bolt 10a5 is located below fastening bolts 10a1 and 10a2, and fastening bolt 10a6 is located below fastening bolts 10a1 and 10a2.

[0062] The fastening bolts 10a to 10a pass through six engaging holes 2g to 2g formed in the first end plate 2. Then, the fastening bolts 10a to 10a pass through six engaging holes 6g to 6g formed in the second end plate 6. Finally, the ends of the fastening bolts 10a to 10a are fixed to the rear surface 6f of the second end plate 6 by fastening nuts 10b to 10b.

[0063] The relative positions of the protrusions 21, 22, 61, and 62, the protrusion surfaces 23, 24, 63, and 64, the engagement holes 2g1 to 2g6 and 6g1 to 6g6, and the fastening bolts 10a1 to 10a6 with respect to the cell stack 4 are as follows:

[0064] To the left of the cell stack 4 (negative side in the Y direction) are located: protrusions 21 and 61; protrusion surfaces 23 and 63; engagement holes 2g1 and 6g1; and fastening bolt 10a1.

[0065] To the right of the cell stack 4 (positive side in the Y direction), there are located: protrusions 22 and 62; protrusion surfaces 24 and 64; engagement holes 2g2 and 6g2; and fastening bolt 10a2.

[0066] Above the cell stack 4 (on the positive side in the Z direction), the following engagement holes 2g3, 2g4, 6g3, and 6g4 are located.

[0067] Below the cell stack 4 (negative side in the Z direction), the engagement holes 2g5, 2g6, 6g5, and 6g6 are located.

[0068] The cell stack 4 is covered with insulating material 7 (first insulating panel 7a and second insulating panel 7b) that is flexible in the thickness direction. The left-right (Y) side surfaces of the insulating material 7 are pressed against the cell stack 4 by fastening bolts 10a1 and 10a2. For example, the contact portion between the insulating material 7 and the fastening bolt 10a1 curves toward the cell stack 4. In addition, the contact portion between the insulating material 7 and the fastening bolt 10a2 curves toward the cell stack 4 (see FIG. 5).

[0069] (Explanation of Embodiment 1 Compared with Reference Embodiment) The fuel cell stack 1 of Embodiment 1 will be further explained below in comparison with the fuel cell stack 90 of the reference embodiment. In the explanation of the fuel cell stack 90 of the reference embodiment, the same members as those in the fuel cell stack 1 (see FIG. 1) will be given the same reference numerals, and their explanations may be omitted.

[0070] FIG. 10 is an exploded perspective view of a fuel cell stack 90 according to a reference embodiment. The fuel cell stack 90 includes a first end plate 81, a first insulating plate 84, a first current collector 3, a cell stack 4, a second current collector 5, a second insulating plate 85, a second end plate 82, four fastening bolts 10a3, 10a4, 10a5, and 10a6, and a heat insulator 83. The first end plate 81, the first insulating plate 84, the first current collector 3, the cell stack 4, the second current collector 5, and the second end plate 82 are stacked in this order in the front-to-rear direction (X). The four fastening bolts 10a3, 10a4, 10a5, and 10a6 connect the first end plate 81 and the second end plate 82. The heat insulator 83 includes insulating panels 83a to 83d.

[0071] In the reference embodiment, the first end plate 81 and the second end plate 82 are made of extra super duralumin material. Extra super duralumin material is conductive. In contrast, in embodiment 1, the first end plate 2 and the second end plate 6 are insulating. Therefore, in the fuel cell stack 1 according to embodiment 1, insulation can be ensured even without insulating plates corresponding to the first insulating plate 84 and the second insulating plate 85 of the reference embodiment.

[0072] In the first embodiment, the first end plate 2 and the second end plate 6 are made of resin. Therefore, the first end plate 2 and the second end plate 6 can be manufactured by resin molding. This is advantageous from the viewpoint of improving the production takt time of the fuel cell stack 1.

[0073] Specifically, in the first embodiment, the first end plate 2 and the second end plate 6 are made of phenolic resin. Phenolic resin is a resin with excellent strength. Therefore, using phenolic resin as the resin constituting the first end plate 2 and the second end plate 6 is advantageous from the viewpoint of ensuring the strength of the first end plate 2 and the second end plate 6.

[0074] Furthermore, the first end plate 2 and the second end plate 6 of the first embodiment are thicker than the first insulating plate 84 and the second insulating plate 85 of the reference embodiment. In other words, the dimensions of the first end plate 2 and the second end plate 6 of the first embodiment in the front-to-rear direction (X) are larger than the dimensions of the first insulating plate 84 and the second insulating plate 85 of the reference embodiment in the front-to-rear direction (X). The thick first end plate 2 and the second end plate 6 are advantageous in terms of ensuring the strength of the first end plate 2 and the second end plate 6. The thickness of the first end plate 2 and the second end plate 6 is, for example, 10 mm or more and 90 mm or less.

[0075] In the reference embodiment, the first end plate 81 and the second end plate 82 are connected to each other by four fastening bolts 10a3 to 10a6. In contrast, in embodiment 1, the first end plate 2 and the second end plate 6 are connected to each other by six fastening bolts 10a1 to 10a6 (see FIG. 1 ). Thus, embodiment 1 uses a larger number of fastening bolts than the reference embodiment. Therefore, in embodiment 1, the first end plate 2 and the second end plate 6 can be supported by more fastening bolts. Therefore, the load that the fastening bolts must support as a whole can be shared among more fastening bolts. This reduces the load that each fastening bolt must support, and reduces the stress applied near each engagement hole in the first end plate 2 and the second end plate 6. This is advantageous from the perspective of ensuring the reliability of the fuel cell stack 1.

[0076] Furthermore, in the first embodiment, the left protruding portions 21 and 61 of the end plates 2 and 6, which protrude to the left (negative side in the Y direction), are provided with engagement holes 2g and 6g, and fastening bolts 10a are engaged with the engagement holes 2g and 6g. The right protruding portions 22 and 62 of the end plates 2 and 6, which protrude to the right (positive side in the Y direction), are provided with engagement holes 2g and 6g, and fastening bolts 10a are engaged with the engagement holes 2g and 6g. The left protruding portions 21 and 61 and the right protruding portions 22 and 62 are positioned differently in the vertical direction (Z). Compared to when the left protruding portions 21 and 61 and the right protruding portions 22 and 62 are positioned the same in the vertical direction (Z), when the left protruding portions 21 and 61 and the right protruding portions 22 and 62 are positioned differently in the vertical direction (Z), it is easier to conserve space when arranging a plurality of fuel cell stacks 1 to form a fuel cell unit.

[0077] Compared to the reference embodiment, the first embodiment is advantageous in that, when a fuel cell unit is constructed by arranging multiple fuel cell stacks 1, the material costs of each fuel cell stack 1 are reduced, the reliability of each fuel cell stack 1 is ensured, and space-saving of the fuel cell unit is achieved. Specifically, as described above, the first embodiment employs the first end plate 2 and the second end plate 6 made of resin rather than metal, and insulating plates are not required, which facilitates reducing material costs of each fuel cell stack 1. Although the first end plate 2 and the second end plate 6 are made of resin, the resin is thick, the resin is phenolic, and a large number of fastening bolts are required, which facilitates ensuring the strength of each fuel cell stack 1. While the left protrusions 21 and 61 and the right protrusions 22 and 62 are provided to increase the number of fastening bolts, the left protrusions 21 and 61 and the right protrusions 22 and 62 are positioned at different positions in the vertical direction (Z), which facilitates space-saving of the fuel cell unit.

[0078] In the first embodiment, the engagement holes 2g, 2g, 6g, and 6g are arranged to straddle a plane including the reference planes 19, 20, 59, and 60, respectively, in the left-right direction (Y). Therefore, the fastening bolt 10a straddles the reference planes 19 and 59, and the fastening bolt 10a straddles the reference planes 20 and 60 in the left-right direction (Y). This straddling enables the above-mentioned space saving without reducing the support strength of the fastening bolts 10a and 10a for the first end plate 2 and the second end plate 6 to an extent that would cause practical problems.

[0079] (Variation 1) Fig. 6 is a cross-sectional view of a fuel cell stack 1 of Variation 1. Fig. 6 shows only the first end plate 2, the first current collector plate 3, the cell stack 4, the second current collector plate 5, and the second end plate 6. The shapes of the first end plate 2 and the second end plate 6 are simplified.

[0080] The first end plate 2 has a first cross section parallel to the front-to-back direction (X) and the left-to-right direction (Y). The first cross section may correspond to the cross section of Figure 6. When observing the first cross section of the first end plate 2, the left side surface 2c of the first end plate 2 and the right side surface 2d of the first end plate 2 approach each other as they approach the cell stack 4.

[0081] The second end plate 6 has a second cross section parallel to the front-to-back direction (X) and the left-to-right direction (Y). The second cross section may correspond to the cross section of Figure 6. When observing the second cross section of the second end plate 6, the left side surface 6c of the second end plate 6 and the right side surface 6d of the second end plate 6 approach each other as they approach the cell stack 4.

[0082] Specifically, in the first cross section, the reference plane 19 of the left side surface 2c is inclined relative to the front-to-rear direction (X), in the first cross section, the reference plane 20 of the right side surface 2d is inclined relative to the front-to-rear direction (X), in the second cross section, the reference plane 59 of the right side surface 6d is inclined relative to the front-to-rear direction (X), and in the second cross section, the reference plane 60 of the left side surface 6c is inclined relative to the front-to-rear direction (X).

[0083] The angle of inclination of the first cross section and the second cross section is, for example, greater than 0° and less than 10°, and may be 0.1° or greater and 8° or less, or 0.2° or greater and 5° or less.

[0084] The dotted arrows in Figure 6 indicate the direction in which heat flows from the cell stack 4 to the first end plate 2 via the first current collector plate 3 in the fuel cell stack 1, and the direction in which heat flows from the cell stack 4 to the second end plate 6 via the second current collector plate 5.

[0085] By configuring the first cross section as described above, it is easy to make the area of ​​the first end plate 2 facing the current collector plate 3 and cell stack 4 smaller than the area of ​​the first end plate 2 facing the outside of the fuel cell stack 1. Furthermore, by configuring the second cross section as described above, it is easy to make the area of ​​the second end plate 6 facing the current collector plate 5 and cell stack 4 smaller than the area of ​​the second end plate 6 facing the outside of the fuel cell stack 1. This makes it difficult for heat to flow from the cell stack 4 to the end plates 2 and 6 via the current collector plates 3 and 5.

[0086] In the fuel cell stack 1, thirteen recesses 6h are provided on the front surface 6e of the second end plate 6, and thirteen elastic members 10c are arranged inside the thirteen recesses 6h (see FIG. 1), but this is not limiting. For example, thirteen recesses 6h may be provided on the rear surface 2f of the first end plate 2, and thirteen elastic members 10c may be arranged inside the thirteen recesses 6h.

[0087] The first end plate 2 and the second end plate 6 are not limited to being made of phenolic resin. They may be made of engineering plastics such as polyphenylene sulfide (PPS) resin. They may be made of thermosetting resins other than phenolic resins, or may be made of thermoplastic resins.

[0088] The first end plate 2 and the second end plate 6 are not limited to being made of resin, but may be made of insulating metal or ceramic.

[0089] The elastic member 10c is not essential.

[0090] Second Embodiment Hereinafter, a second embodiment will be described with reference to FIGS.

[0091] [2-1. Configuration] Fig. 7 is a front view of a fuel cell unit 100 according to a second embodiment. Fig. 8 is an enlarged view of a portion (the portion surrounded by dashed line 151) of the front view of Fig. 7. Fig. 9 is a perspective view of the fuel cell unit 100 according to the second embodiment. Fig. 7 shows an example in which the positioning member 30 is attached to the first end plate 2, while Fig. 9 shows an example in which the positioning member 30 is attached to the second end plate 6. The positioning member 30 may be attached to either the first end plate 2 or the second end plate 6, or may be attached to both.

[0092] The fuel cell unit 100 includes four fuel cell stacks 1 and a positioning member 30. The positioning member 30 allows the four fuel cell stacks to be arranged at a predetermined interval. The configuration of each fuel cell stack 1 is the same as in the first embodiment. In the second embodiment, the left-right direction (Y) is parallel to the mounting surface ps2 on which each fuel cell stack 1 is mounted. In the second embodiment, the mounting surface ps2 of each fuel cell stack 1 is formed by at least one of a recess in the lower surface 2b of the first end plate 2 and a recess in the lower surface 6b of the second end plate 6. In the second embodiment, for ease of explanation, the four fuel cell stacks 1 may be distinguished by being referred to as a first fuel cell stack 1A, a second fuel cell stack 1B, a third fuel cell stack 1C, and a fourth fuel cell stack 1D.

[0093] The first fuel cell stack 1A, the second fuel cell stack 1B, the third fuel cell stack 1C, and the fourth fuel cell stack 1D are arranged adjacent to one another in the left-right direction (Y) in this order. The first end plate 2 and the second end plate 6 of the first fuel cell stack 1A and the first end plate 2 and the second end plate 6 of the second fuel cell stack 1B are adjacent to one another in the left-right direction (Y). The first end plate 2 and the second end plate 6 of the second fuel cell stack 2B and the first end plate 2 and the second end plate 6 of the third fuel cell stack 1C are adjacent to one another in the left-right direction (Y). The first end plate 2 and the second end plate 6 of the third fuel cell stack 1C and the first end plate 2 and the second end plate 6 of the fourth fuel cell stack 1D are adjacent to one another in the left-right direction (Y).

[0094] The positioning member 30 includes a base portion 30a, first support portions 30b1 to 30b4, second support portions 30c1 to 30c3, and third support portions 30d1 to 30d2. The base portion 30a is disposed in a predetermined installation space of the fuel cell unit 100. The first support portions 30b1 to 30b4 support the bottom surfaces of the first fuel cell stack 1A to the fourth fuel cell stack 1D. The second support portions 30c1 to 30c3 support the side surfaces of adjacent fuel cell stacks 1. The third support portions 30d1 and 30d2 support the side surfaces of the first fuel cell stack 1A and the fourth fuel cell stack 1D located at both ends.

[0095] The first support portion 30b1 supports the lower surface 2b of the first end plate 2 of the first fuel cell stack 1A (see FIG. 7). Specifically, the first support portion 30b1 is configured to be convex upward (positive side in the Z direction). Meanwhile, two legs 2j are provided on the left and right sides of the lower surface 2b of the first end plate 2 of the first fuel cell stack 1A. That is, the lower surface 2b of the first end plate 2 has a recess. The width L1 of the protrusion of the first support portion 30b1 in the left-right direction (Y) corresponds to the distance between the two legs 2j on the lower surface 2b. The protrusion of the first support portion 30b1 fits into the recess on the lower surface 2b of the first end plate 2. In this way, the first fuel cell stack 1A can be positioned in the left-right direction (Y).

[0096] The first support portion 30b2 supports the lower surface 2b of the first end plate 2 of the second fuel cell stack 1B (see FIG. 7). Specifically, the first support portion 30b2 is configured to be convex upward (positive side in the Z direction). Meanwhile, two legs 2j are provided on the left and right sides of the lower surface 2b of the first end plate 2 of the second fuel cell stack 1B. That is, the lower surface 2b of the first end plate 2 has a recess. The width L1 of the protrusion of the first support portion 30b2 in the left-right direction (Y) corresponds to the distance between the two legs 2j on the lower surface 2b. The protrusion of the first support portion 30b2 fits into the recess on the lower surface 2b of the first end plate 2. In this way, the second fuel cell stack 1B can be positioned in the left-right direction (Y).

[0097] The first support portion 30b3 supports the lower surface 2b of the first end plate 2 of the third fuel cell stack 1C (see FIG. 7). Specifically, the first support portion 30b3 is configured to be convex upward (positive side in the Z direction). Meanwhile, two legs 2j are provided on the left and right sides of the lower surface 2b of the first end plate 2 of the third fuel cell stack 1C. That is, the lower surface 2b of the first end plate 2 has a recess. The width L1 of the protrusion of the first support portion 30b3 in the left-right direction (Y) corresponds to the distance between the two legs 2j on the lower surface 2b. The protrusion of the first support portion 30b3 fits into the recess on the lower surface 2b of the first end plate 2. In this way, the third fuel cell stack 1C can be positioned in the left-right direction (Y).

[0098] The first support portion 30b4 supports the lower surface 2b of the first end plate 2 of the fourth fuel cell stack 1D (see FIG. 7). Specifically, the first support portion 30b4 is configured to be convex upward (positive side in the Z direction). Meanwhile, two legs 2j are provided on the left and right sides of the lower surface 2b of the first end plate 2 of the fourth fuel cell stack 1D. That is, the lower surface 2b of the first end plate 2 has a recess. The width L1 of the protrusion of the first support portion 30b4 in the left-right direction (Y) corresponds to the distance between the two legs 2j on the lower surface 2b. The protrusion of the first support portion 30b4 fits into the recess on the lower surface 2b of the first end plate 2. In this way, the fourth fuel cell stack 1D can be positioned in the left-right direction (Y).

[0099] The second support portion 30c1 is configured to support the right side surface 2d of the adjacent first fuel cell stack 1A and the left side surface 2c of the adjacent second fuel cell stack 1B at a predetermined distance L2. Specifically, the second support portion 30c1 constitutes a defining member having a pair of flat surfaces that face each other in the left-right direction (Y) at a predetermined distance L2. This allows the first fuel cell stack 1A and the second fuel cell stack 1B to be positioned in the left-right direction (Y).

[0100] The second support portion 30c2 is configured to support the right side surface 2d of the adjacent second fuel cell stack 1B and the left side surface 2c of the adjacent third fuel cell stack 1C at a predetermined distance L2. Specifically, the second support portion 30c2 constitutes a defining member having a pair of flat surfaces that face each other in the left-right direction (Y) at the predetermined distance L2. This allows the second fuel cell stack 1B and the third fuel cell stack 1C to be positioned in the left-right direction (Y).

[0101] The second support portion 30c3 is configured to support the right side surface 2d of the adjacent third fuel cell stack 1C and the left side surface 2c of the adjacent fourth fuel cell stack 1D at a predetermined distance L2. Specifically, the second support portion 30c3 constitutes a defining member having a pair of flat surfaces that face each other at the predetermined distance L2 in the left-right direction (Y). This allows the third fuel cell stack 1C and the fourth fuel cell stack 1D to be positioned in the left-right direction (Y).

[0102] The third support portion 30d1 is configured to support the left side surface 2c of the first fuel cell stack 1A from the outside, and the third support portion 30d2 is configured to support the right side surface 2d of the fourth fuel cell stack 1D from the outside.

[0103] However, the positioning member 30 may be omitted. That is, the first fuel cell stack 1A to the fourth fuel cell stack 1D may be placed on a flat surface in the fuel cell unit 100.

[0104] The following describes the positional relationship between adjacent stacks, taking the first fuel cell stack 1A and the second fuel cell stack 1B as an example. The same applies to the positional relationship between the second fuel cell stack 1B and the third fuel cell stack 1C, and the positional relationship between the third fuel cell stack 1C and the fourth fuel cell stack 1D.

[0105] The right protrusion 22 of the first fuel cell stack 1A and the left protrusion 21 of the second fuel cell stack 1B are located at different positions in the vertical direction (Z) (see FIG. 8). The engagement hole 2g of the first fuel cell stack 1A and the engagement hole 2g of the second fuel cell stack 1B are located at different positions in the vertical direction (Z).

[0106] The right protrusion 62 of the first fuel cell stack 1A and the left protrusion 61 of the second fuel cell stack 1B are provided at different positions in the vertical direction (Z). The engagement hole 6g of the first fuel cell stack 1A and the engagement hole 6g of the second fuel cell stack 1B are provided at different positions in the vertical direction (Z).

[0107] The right protrusion 22 of the first fuel cell stack 1A and the left protrusion 21 of the second fuel cell stack 1B are arranged so as to intersect with an imaginary plane 152 (see FIG. 8 ). Here, the imaginary plane 152 is an imaginary plane for explaining the positional relationship between the protrusions 21 and 22. The imaginary plane 152 is a plane parallel to the up-down direction (Z) and the front-rear direction (X). Specifically, the imaginary plane 152 is a plane on which the distance from the reference plane 20 of the first fuel cell stack 1A is equal to the distance from the reference plane 19 of the second fuel cell stack 1B.

[0108] The right protrusion 62 of the first fuel cell stack 1A and the left protrusion 61 of the second fuel cell stack 1B are arranged so as to intersect with an imaginary plane 152 (not shown). Here, the imaginary plane 152 is an imaginary plane for explaining the positional relationship between the protrusions 61 and 62. The imaginary plane 152 is a plane parallel to the up-down direction (Z) and the front-rear direction (X). Specifically, the imaginary plane 152 is a plane on which the distance from the reference plane 60 of the first fuel cell stack 1A is equal to the distance from the reference plane 59 of the second fuel cell stack 1B.

[0109] On the right side surface 2d of the first fuel cell stack 1A, the distance from the reference plane 20 to the tip of the right protruding surface 24 is defined as the protruding height ht1 of the right protruding portion 22 in the right direction (positive side in the Y direction) (see FIG. 8 ). On the left side surface 2c of the second fuel cell stack 1B, the distance from the reference plane 19 to the tip of the left protruding surface 23 is defined as the protruding height ht2 of the left protruding portion 21 in the left direction (negative side in the Y direction). In one example, the protruding height ht1 of the right protruding portion 22 and the protruding height ht2 of the left protruding portion 21 are equal. In the second embodiment, the width (L2) in the left-right direction (Y) of the defining member formed by the second support portion 30c1 is smaller than the sum of the protruding height ht1 of the right protruding portion 22 of the first fuel cell stack 1A and the protruding height ht2 of the left protruding portion 21 of the second fuel cell stack 1B. This makes it easy to position the first fuel cell stack 1A and the second fuel cell stack 1B appropriately close to each other.

[0110] On the other hand, in the second embodiment, the width (L2) in the left-right direction (Y) of the defining member formed by the second support portion 30c1 is greater than the greater of the protrusion height ht1 of the right protrusion portion 22 of the first fuel cell stack 1A and the protrusion height ht2 of the left protrusion portion 21 of the second fuel cell stack 1B, thereby preventing contact between the first fuel cell stack 1A and the second fuel cell stack 1B.

[0111] In the fuel cell unit 100, the number of fuel cell stacks 1 is not limited to four, as long as it is plural.

[0112] (Other Embodiments) As described above, Embodiments 1 and 2 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in Embodiments 1 and 2 above to create new embodiments.

[0113] The above description of the embodiments discloses the following techniques.

[0114] (Technology 1) A solar cell module includes a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a plurality of fastening bolts, wherein the first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate are stacked in this order in a stacking direction of the cell stack, and the plurality of fastening bolts connect the first end plate and the second end plate, and the plurality of fastening bolts include a first fastening bolt and a second fastening bolt, and when a direction perpendicular to the stacking direction is defined as a left-right direction, each of the first end plate and the second end plate has: a left protruding portion located to the left of the cell stack and protruding leftward, a left engagement hole provided in the left protruding portion and engaged with the first fastening bolt, a right protruding portion located to the right of the cell stack and protruding rightward, and a right engagement hole provided in the right protruding portion and engaged with the second fastening bolt, When a direction perpendicular to the stacking direction and the left-right direction is defined as a vertical direction, the left protrusion and the right protrusion are provided at different positions in the vertical direction.

[0115] In this configuration, the multiple fastening bolts can contribute to improving the strength of the fuel cell stack. Meanwhile, when arranging multiple fuel cell stacks to form a fuel cell unit, the width of the fuel cell stacks in the left-right direction can be reduced while preventing interference or contact between the protruding portions of adjacent fuel cell stacks. Therefore, this configuration is suitable for saving space in the fuel cell unit while ensuring the reliability of the fuel cell stack.

[0116] (Technology 2) The fuel cell stack according to Technology 1, wherein the first end plate and the second end plate have insulating properties.

[0117] In this configuration, since the first end plate and the second end plate are insulating, there is no need for an insulating member separate from the first end plate and the second end plate, which simplifies the components of the fuel cell stack.

[0118] (Technology 3) The fuel cell stack according to Technology 1 or Technology 2, wherein the first end plate and the second end plate are made of resin.

[0119] In this configuration, the first end plate and the second end plate can be manufactured by resin molding, which can improve the production takt time of the fuel cell stack.

[0120] (Technology 4) The fuel cell stack according to any one of Technology 1 to Technology 3, wherein the first end plate and the second end plate are made of phenolic resin.

[0121] In this configuration, the first end plate and the second end plate are made of a phenolic resin, which has excellent strength, making it easier to ensure the reliability of the fuel cell stack.

[0122] (Technology 5) A fuel cell stack according to any one of Technology 1 to Technology 4, wherein the first end plate has a left side surface and a right side surface, the first end plate has a cross section parallel to the stacking direction and the left-right direction, and in the cross section, the left side surface and the right side surface approach each other as they approach the cell stack.

[0123] This configuration makes it easy to reduce the area of ​​the first end plate facing the cell stack. This makes it difficult for heat generated in the cell stack during power generation to be transferred to the first end plate via the current collector plate, making it easy to suppress heat loss. This can improve the efficiency of waste heat utilization, for example.

[0124] (Technology 6) A fuel cell stack described in any one of Technology 1 to Technology 5, further comprising an insulating material that is flexible in the thickness direction and covers the cell stack, the insulating material being pressed against the cell stack by the first fastening bolts and the second fastening bolts, and the contact portions between the insulating material and the first fastening bolts and the contact portions between the insulating material and the second fastening bolts being curved toward the cell stack.

[0125] According to this configuration, the first and second fastening bolts can easily increase the adhesion between the heat insulating material and the cell stack, making it easier to improve the heat insulating effect and reduce heat loss, which can improve the efficiency of utilizing exhaust heat, for example.

[0126] (Technology 7) A fuel cell stack according to any one of Technology 1 to Technology 6, wherein the plurality of fastening bolts further include a third fastening bolt, a fourth fastening bolt, a fifth fastening bolt, and a sixth fastening bolt, the third fastening bolt being located to the left of the fourth fastening bolt, the fifth fastening bolt being located to the left of the sixth fastening bolt, the third fastening bolt being located above the first fastening bolt and the second fastening bolt, the fourth fastening bolt being located above the first fastening bolt and the second fastening bolt, the fifth fastening bolt being located below the first fastening bolt and the second fastening bolt, and the sixth fastening bolt being located below the first fastening bolt and the second fastening bolt.

[0127] In this configuration, the load that the fastening bolts must support as a whole can be shared among at least six fastening bolts. This reduces the load that each fastening bolt must support, and can reduce stress applied to the first end plate and the second end plate near the engagement holes. This is advantageous from the perspective of ensuring the reliability of the fuel cell stack.

[0128] (Technology 8) A fuel cell stack according to any one of Technology 1 to Technology 7, wherein the first end plate or the second end plate has a plurality of recesses, the fuel cell stack further comprises a plurality of elastic members, and the plurality of elastic members are arranged inside the plurality of recesses.

[0129] This configuration allows the repulsive force of the multiple elastic members to be uniformly exerted in the in-plane direction of the elastic members, which makes it easier to stably hold the cell stack between the first end plate or the second end plate, and reduces warping of the first end plate or the second end plate, thereby ensuring the reliability of the fuel cell stack.

[0130] (Technology 9) A fuel cell stack described in any one of Technology 1 to Technology 8, wherein each of the first end plate and the second end plate has a left side surface and a right side surface, and when the position of the left protrusion in the vertical direction is defined as a left protrusion position, and the position of the right protrusion in the vertical direction is defined as a right protrusion position, on each of the first end plate and the second end plate, on the left side surface, the right protrusion position is located to the right of the left protrusion position, and on the right side surface, the left protrusion position is located to the left of the right protrusion position.

[0131] This configuration, when arranging multiple fuel cell stacks to form a fuel cell unit, can reduce the left-right area occupied by adjacent fuel cell stacks while preventing interference or contact between the protruding portions of one fuel cell stack and the other. Therefore, this configuration is suitable for saving space in the fuel cell unit while ensuring the reliability of the fuel cell stack.

[0132] (Technology 10) The fuel cell stack according to any one of Technology 1 to Technology 9, wherein the left-right direction is a direction parallel to a mounting surface on which the fuel cell stack is mounted.

[0133] This configuration is an example of a configuration that can effectively avoid the above-mentioned interference.

[0134] (Technology 11) A fuel cell stack described in any one of Technology 1 to Technology 10, wherein each of the first end plate and the second end plate has a left side and a right side, and the left side of the first end plate, the right side of the first end plate, the left side of the second end plate and the right side of the second end plate each include a reference plane parallel to the up-down direction and the front-to-back direction, and with respect to the left-to-right direction, the first fastening bolt is arranged to straddle a plane including the left side of the first end plate and a plane including the left side of the second end plate, and the second fastening bolt is arranged to straddle a plane including the right side of the first end plate and a plane including the right side of the second end plate.

[0135] This configuration enables the above-mentioned space saving without reducing the support strength of the first and second end plates by the first and second fastening bolts to an extent that would cause practical problems. Note that the plane including the left side surface of the first end plate and the plane including the left side surface of the second end plate may be the same plane or different planes. The plane including the right side surface of the first end plate and the plane including the right side surface of the second end plate may be the same plane or different planes.

[0136] (Technology 12) A fuel cell stack includes a plurality of fuel cell stacks, each of the plurality of fuel cell stacks includes a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a fastening bolt, the first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate are stacked in this order in a stacking direction of the cell stack, and the fastening bolt connects the first end plate and the second end plate, the plurality of fuel cell stacks include a first fuel cell stack and a second fuel cell stack, and when a direction perpendicular to the stacking direction is defined as a left-right direction, the first fuel cell stack and the second fuel cell stack are arranged adjacent to each other in the left-right direction such that the first fuel cell stack is located to the left of the second fuel cell stack, and each of the first end plate and the second end plate of the first fuel cell stack has: a right protrusion located to the right of the cell stack of the first fuel cell stack and protruding rightward, a right engagement hole provided in the right protrusion, with which the fastening bolt of the first fuel cell stack engages; and a right engagement hole provided in the right protrusion, with which the fastening bolt of the first fuel cell stack engages; wherein each of the first end plate and the second end plate of the second fuel cell stack has a left protrusion located to the left of the cell stack of the second fuel cell stack and protruding leftward; and a left engagement hole provided in the left protrusion, with which the fastening bolt of the second fuel cell stack engages; and when a direction perpendicular to the stacking direction and the left-right direction is defined as a vertical direction, the right protrusion and the left protrusion are provided at different positions in the vertical direction.

[0137] This configuration is suitable for saving space in the fuel cell unit while ensuring the reliability of the fuel cell stack.

[0138] (Technology 13) The fuel cell unit according to Technology 12, wherein the right protrusion and the left protrusion are provided so as to intersect with an imaginary plane parallel to the up-down direction and the front-rear direction.

[0139] This configuration makes it easy to bring adjacent fuel cell stacks close to each other while avoiding contact between them, which makes it easy to save space in the fuel cell unit.

[0140] (Technology 14) The fuel cell unit according to Technology 12 or Technology 13, wherein the left-right direction is a direction parallel to a mounting surface on which the first fuel cell stack and the second fuel cell stack are mounted.

[0141] This configuration is an example of a configuration that can effectively avoid the above-mentioned interference.

[0142] (Technology 15) The fuel cell unit according to any one of Technology 12 to Technology 14, further comprising a positioning member for arranging the plurality of fuel cell stacks at predetermined intervals.

[0143] This configuration makes it easy to arrange a plurality of fuel cell stacks at predetermined intervals.

[0144] (Technology 16) A fuel cell unit according to Technology 15, wherein the positioning member has a defining member that defines the first fuel cell stack and the second fuel cell stack at a predetermined interval, and the width of the defining member in the left-right direction is smaller than the sum of the protruding height of the right protruding portion and the protruding height of the left protruding portion.

[0145] This configuration makes it easy to place adjacent fuel cell stacks close to each other, which makes it easy to save space in the fuel cell unit.

[0146] The technology of the present disclosure is useful for large-scale fuel cell units equipped with multiple fuel cell stacks. The fuel cell stack of the present disclosure is applicable to pure hydrogen fuel cells. Pure hydrogen fuel cells do not require a reformer. The fuel cell stack of the present disclosure is also applicable to fuel cells that have a reformer.

Claims

1. A fuel cell stack comprising a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a plurality of fastening bolts, wherein the first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate are laminated in this order in the stacking direction of the cell stack, the plurality of fastening bolts connect the first end plate and the second end plate, the plurality of fastening bolts include a first fastening bolt and a second fastening bolt, and when a direction orthogonal to the stacking direction is defined as the left-right direction, each of the first end plate and the second end plate has a left protruding portion located on the left side of the cell stack and protruding leftward, a left engaging hole provided in the left protruding portion and engaged with the first fastening bolt, a right protruding portion located on the right side of the cell stack and protruding rightward, and a right engaging hole provided in the right protruding portion and engaged with the second fastening bolt, and when a direction orthogonal to the stacking direction and the left-right direction is defined as the up-down direction, the left protruding portion and the right protruding portion are provided at different positions in the up-down direction.

2. The fuel cell stack according to claim 1, wherein the first end plate and the second end plate have insulating properties.

3. The fuel cell stack according to claim 1, wherein the first end plate and the second end plate are made of resin.

4. The fuel cell stack according to claim 1, wherein the first end plate and the second end plate are made of phenolic resin.

5. The first end plate has a left side surface and a right side surface, the first end plate has a cross-section parallel to the stacking direction and the left-right direction, and in the cross-section, the left side surface and the right side surface approach each other as they approach the cell stack. The fuel cell stack according to claim 1.

6. Further comprising a heat insulating material having flexibility in the thickness direction and covering the cell stack, the heat insulating material is pressed against the cell stack by the first fastening bolt and the second fastening bolt, and the contact portions between the heat insulating material and the first fastening bolt and between the heat insulating material and the second fastening bolt are curved toward the cell stack. The fuel cell stack according to claim 1.

7. The plurality of fastening bolts further includes a third fastening bolt, a fourth fastening bolt, a fifth fastening bolt, and a sixth fastening bolt, wherein the third fastening bolt is located on the left side of the fourth fastening bolt, the fifth fastening bolt is located on the left side of the sixth fastening bolt, the third fastening bolt is located above the first fastening bolt and the second fastening bolt, the fourth fastening bolt is located above the first fastening bolt and the second fastening bolt, the fifth fastening bolt is located below the first fastening bolt and the second fastening bolt, the sixth fastening bolt is located below the first fastening bolt and the second fastening bolt. The fuel cell stack according to claim 1.

8. The first end plate or the second end plate has a plurality of recesses, the fuel cell stack further includes a plurality of elastic members, the plurality of elastic members are disposed inside the plurality of recesses. The fuel cell stack according to claim 1.

9. Each of the first end plate and the second end plate has a left side surface and a right side surface, when defining the position of the left protrusion in the vertical direction as the left protrusion position and the position of the right protrusion in the vertical direction as the right protrusion position, in each of the first end plate and the second end plate, on the left side surface, the right protrusion position is located on the right side compared to the left protrusion position, on the right side surface, the left protrusion position is located on the left side compared to the right protrusion position. The fuel cell stack according to claim 1.

10. The left-right direction is a direction parallel to the placement surface on which the fuel cell stack is placed. The fuel cell stack according to claim 1.

11. Each of the first end plate and the second end plate has a left side surface and a right side surface. Each of the left side surface of the first end plate, the right side surface of the first end plate, the left side surface of the second end plate, and the right side surface of the second end plate includes a reference plane parallel to the vertical direction and the front-rear direction. With respect to the left-right direction, the first fastening bolt is provided so as to straddle the plane including the left side surface of the first end plate and the plane including the left side surface of the second end plate. The second fastening bolt is provided so as to straddle the plane including the right side surface of the first end plate and the plane including the right side surface of the second end plate. The fuel cell stack according to any one of claims 1 to 10.

12. A fuel cell unit includes a plurality of fuel cell stacks. Each of the plurality of fuel cell stacks includes a first end plate, a first current collector plate, a cell stack, a second current collector plate, a second end plate, and a fastening bolt. The first end plate, the first current collector plate, the cell stack, the second current collector plate, and the second end plate are stacked in this order in the stacking direction of the cell stack. The fastening bolt connects the first end plate and the second end plate. The plurality of fuel cell stacks includes a first fuel cell stack and a second fuel cell stack. When a direction orthogonal to the stacking direction is defined as the left-right direction, the first fuel cell stack and the second fuel cell stack are arranged adjacent to each other in the left-right direction such that the first fuel cell stack is located on the left side of the second fuel cell stack. Each of the first end plate and the second end plate in the first fuel cell stack is located on the right side of the cell stack of the first fuel cell stack and has a right protrusion protruding rightward and a right engagement hole provided in the right protrusion and engaged with the fastening bolt of the first fuel cell stack. Each of the first end plate and the second end plate in the second fuel cell stack is located on the left side of the cell stack of the second fuel cell stack and has a left protrusion protruding leftward and a left engagement hole provided in the left protrusion and engaged with the fastening bolt of the second fuel cell stack. When a direction orthogonal to the stacking direction and the left-right direction is defined as the up-down direction, the right protrusion and the left protrusion are provided at different positions in the up-down direction.

13. The fuel cell unit according to claim 12, wherein the right protrusion and the left protrusion are provided so as to intersect a virtual plane parallel to the up-down direction and the front-rear direction.

14. The fuel cell unit according to claim 12, wherein the left-right direction is a direction parallel to the mounting surface on which the first fuel cell stack and the second fuel cell stack are mounted.

15. The fuel cell unit according to any one of claims 12 to 14, further comprising a positioning member for arranging the plurality of fuel cell stacks at a predetermined interval.

16. The positioning member has a defining member that defines the first fuel cell stack and the second fuel cell stack at a predetermined interval, and a width of the defining member in the left-right direction is smaller than a sum of a protruding height protruding rightward of the right protruding portion and a protruding height protruding leftward of the left protruding portion. The fuel cell unit according to claim 15.

Images