Fuel cell

Abstract

A fuel cell is provided with: a fuel cell stack provided with a plurality of laminated plate-shaped single cells; a pair of end plates that sandwich the fuel cell stack from both sides in the stacking direction of the single cells; a plurality of fastening members that respectively rotate about respective independent first axes extending in the stacking direction and fasten the pair of end plates to each other; and a rotating body configured so as to be capable of rotating about a second axis extending in the stacking direction, the rotating body being provided on a surface on the outside in the stacking direction of either one of the pair of end plates. The rotating body is configured so that a rotational force during rotation is transmitted simultaneously as a rotational force in a tightening direction with respect to the plurality of fastening members.

Description

Technical Field

[0001] This disclosure relates to fuel cells. Background Technology

[0002] Currently, fuel cells are known, for example, as shown in Japanese Patent Application Publication No. 2013-20886. Such a fuel cell comprises: a fuel cell stack having multiple stacked individual cells; and a pair of end plates clamping the fuel cell stack from both sides in the stacking direction of the individual cells. The pair of end plates are fastened with multiple bolts to impart compressive force to the fuel cell stack. Summary of the Invention

[0003] The problem that the invention aims to solve

[0004] However, in fuel cells like the one described above, the compression force applied to the fuel cell stack is inconsistent because multiple bolts are tightened sequentially. Therefore, the surface pressure is not uniformly applied to the individual cells constituting the fuel cell stack, leading to instability in the quality of the fuel cell.

[0005] Solution for solving the problem

[0006] A fuel cell according to one embodiment of the present disclosure comprises: a fuel cell stack having a plurality of stacked, plate-shaped individual cells, each individual cell having a power generation section and a pair of partitions clamping the power generation section; a pair of end plates clamping the fuel cell stack from both sides of the individual cells in the stacking direction; a plurality of fastening members that are each rotatable about an independent first axis extending along the stacking direction and fastening the pair of end plates to each other; and a rotating body configured to rotatably rotate about a second axis extending along the stacking direction and disposed on the outer surface of either of the pair of end plates in the stacking direction, wherein the rotating body is configured such that rotational force during rotation is simultaneously transmitted relative to the rotational force of the plurality of fastening members in the tightening direction. Attached Figure Description

[0007] Figure 1 This is a cross-sectional schematic diagram of a fuel cell according to one embodiment.

[0008] Figure 2 yes Figure 1 A top view of a fuel cell.

[0009] Figure 3 It is an exploded 3D view of a single cell.

[0010] Figure 4 This is a cross-sectional schematic diagram of a modified fuel cell.

[0011] Figure 5 yes Figure 4A top view of a fuel cell.

[0012] Figure 6 This is a top view of another modified fuel cell.

[0013] Figure 7 This is a top view of yet another modified fuel cell. Detailed Implementation

[0014] Hereinafter, one embodiment will be described with reference to the accompanying drawings.

[0015] <Fuel Cell 11>

[0016] like Figure 1 As shown, the fuel cell 11 includes a fuel cell stack 13 and a pair of end plates 14. The fuel cell stack 13 includes a plurality of rectangular plate-shaped individual cells 12 for generating electricity. The plurality of individual cells 12 are stacked in their thickness direction. The pair of end plates 14 clamp the fuel cell stack 13 from both sides in the stacking direction Z of the individual cells 12.

[0017] The pair of end plates 14 are, for example, square in shape and made of metal. One of the pair of end plates 14 is designated as the first end plate 14a, and the other is designated as the second end plate 14b. The pair of end plates 14 are fastened together by a plurality of (four in this example) metal fastening members 15 that rotate around their respective independent first axes J1 extending along the stacking direction Z, thereby compressing the fuel cell stack 13 in the stacking direction Z. That is, the fuel cell 11 has a plurality of fastening members 15 that rotate around their respective independent first axes J1 extending along the stacking direction Z and fasten the pair of end plates 14 together.

[0018] A junction box for collecting electricity (not shown) and an insulating plate for insulation (not shown) are sandwiched between each of the pair of end plates 14 and the fuel cell stack 13.

[0019] like Figure 1 and Figure 2 As shown, each fastening member 15 has a bolt 16 with a first axis J1 as its axis and an annular nut 17 with the first axis J1 as its axis. The bolt 16 has a shaft portion 18 and a hexagonal head 19 provided at one end of the shaft portion 18. An annular gear portion 20 is integrally formed on the outer periphery of the nut 17. Circular through holes 21 are formed near the four corners of each pair of end plates 14. The centers of the four through holes 21 formed in each end plate 14 are arranged on the same circumference.

[0020] The shaft portion 18 of the bolt 16 passes through the insertion holes 21 of the pair of end plates 14 in such a way that they connect the pair of end plates 14. That is, the shaft portion 18 of the bolt 16 passes through the insertion hole 21 of the first end plate 14a and the insertion hole 21 of the second end plate 14b, which is opposite to the insertion hole 21 in the stacking direction Z.

[0021] In this case, the tip of the shaft portion 18 of the bolt 16 protrudes outward in the Z-direction of the first outer surface 22 of the first end plate 14a, which is the outer side in the Z-direction of the stacking direction, and the head 19 of the bolt 16 is fixed by welding or the like in contact with the second outer surface 23 of the second end plate 14b, which is the outer side in the Z-direction of the stacking direction. Therefore, the bolt 16 cannot rotate relative to the through hole 21.

[0022] Nuts 17 are screwed onto the top ends of the shaft portions 18 of the four bolts 16 that protrude from the first outer surface 22 of the first end plate 14a. And, by rotating the nuts 17 in the tightening direction, a pair of end plates 14 are thus fastened by the four nuts 17 and the four bolts 16.

[0023] A gear 24 is provided at the center of the first outer surface 22 of the first end plate 14a, configured as an example of a rotating body capable of rotating in both forward and reverse directions around a second axis J2 extending along the stacking direction Z. That is, the fuel cell 11 includes a gear 24, an example of a rotating body, provided on the first outer surface 22 of the first end plate 14a. The second axis J2 extends through the center of the pair of end plates 14 and parallel to the first axis J1. The gear 24 has a larger outer diameter and greater thickness than the nut 17.

[0024] One gear 24 meshes with the gear portions 20 of the four nuts 17. Therefore, when rotating, the gear 24 simultaneously transmits rotational force in direct contact with the gear portions 20 of the four nuts 17. That is, the gear 24 is configured such that rotational force during rotation is simultaneously transmitted relative to the rotational force of the four nuts 17 in the tightening direction. A hexagonal protrusion 25 is formed at the center of the gear 24 for engaging with a general-purpose tool such as a socket wrench when the gear 24 is rotated.

[0025] <Single Battery 12>

[0026] like Figure 1 and Figure 3 As shown, multiple single cells 12 are stacked in the shape of rectangular plates to form a fuel cell stack 13. Each single cell 12 has a rectangular plate-shaped power generation unit 26, a pair of rectangular sheet-shaped gas diffusion layers 27 that hold the power generation unit 26, and a pair of rectangular plate-shaped separators 28. That is, the single cell 12 has a structure in which a pair of gas diffusion layers 27, a power generation unit 26, and a pair of separators 28 are stacked.

[0027] In the following description, the long side direction, short side direction, and thickness direction of the single cell 12 are respectively designated as the long side direction X, the short side direction Y, and the stacking direction Z. The long side direction X, the short side direction Y, and the stacking direction Z are mutually orthogonal. The thickness direction of the single cell 12 is the same as the stacking direction Z.

[0028] like Figure 3 As shown, the power generation unit 26 includes a rectangular plate-shaped resin frame member 29 and a rectangular sheet-shaped power generation section 30 supported on the frame member 29. The power generation section 30 is, for example, constructed of a membrane electrode assembly (MEA). The frame member 29 has a rectangular opening 31 at its center.

[0029] The frame member 29 supports the power generation unit 30 in a manner that houses the power generation unit 30 within the opening 31. The power generation unit 30 is held in the stacking direction Z by a pair of gas diffusion layers 27. A pair of partitions 28 hold the power generation unit 26 in the stacking direction Z from the outside of the pair of gas diffusion layers 27. One of the partitions 28 (cathode side) is designated as the first partition 28a, and the other (anode side) is designated as the second partition 28b.

[0030] <Flow path structure of single cell 12>

[0031] like Figure 1 and Figure 3 As shown, three rectangular through holes are formed at both ends of the single cell 12 that hold the power generation part 30 in the long side direction X, namely the frame member 29 and the two ends of the pair of partitions 28 that hold the power generation part 30 in the long side direction X.

[0032] The three through holes at one end of the long side X of the single cell 12 are configured as a fuel gas supply hole 32, a cooling medium discharge hole 33, and an oxidant gas discharge hole 34. The three through holes at the other end of the long side X of the single cell 12 are configured as an oxidant gas supply hole 35, a cooling medium supply hole 36, and a fuel gas discharge hole 37.

[0033] Fuel gas supply port 32 constitutes an inlet-side fuel gas manifold for supplying fuel gas in the fuel cell stack 13. Fuel gas discharge port 37 constitutes an outlet-side fuel gas manifold for discharging fuel gas in the fuel cell stack 13. Oxidant gas supply port 35 constitutes an inlet-side oxidant gas manifold for supplying oxidant gas in the fuel cell stack 13. Oxidant gas discharge port 34 constitutes an outlet-side oxidant gas manifold for discharging oxidant gas in the fuel cell stack 13. Each of these manifolds extends along the stacking direction Z of the individual cells 12 in the configuration of the fuel cell stack 13.

[0034] An oxidant gas flow path (not shown) is formed between the frame member 29, the power generation unit 30, and the first partition 28a. This oxidant gas flow path allows oxidant gas supplied from the oxidant gas supply hole 35 to flow through the power generation unit 30 in the long side direction X and towards the oxidant gas discharge hole 34. This oxidant gas flow path is formed by multiple grooves on the surface of the first partition 28a on the side of the power generation unit 30.

[0035] A fuel gas flow path is formed between the frame member 29, the power generation unit 30, and the second partition 28b. This fuel gas flow path allows fuel gas supplied from the fuel gas supply hole 32 to flow through the power generation unit 30 in the longitudinal direction X and towards the fuel gas discharge hole 37. This fuel gas flow path is formed by a plurality of grooves 38 on the surface of the second partition 28b on the side of the power generation unit 30.

[0036] In the case where multiple individual cells 12 are stacked to form a fuel cell stack 13, a cooling medium flow path (not shown) is formed between the first separator 28a of one of two adjacent individual cells 12 along the stacking direction Z and the second separator 28b of the other individual cell 12. This cooling medium flow path allows the cooling medium supplied from the cooling medium supply hole 36 to flow to the cooling medium discharge hole 33.

[0037] <Power generation based on fuel cell stack 13>

[0038] like Figure 1 and Figure 3 As shown, in each individual cell 12 constituting the fuel cell stack 13, an oxidant gas containing oxygen is supplied to one side (cathode side) of the power generation section 30 in the stacking direction Z, and a fuel gas containing hydrogen is supplied to the other side (anode side) of the power generation section 30 in the stacking direction Z. Thus, the individual cell 12 generates electricity based on the electrochemical reaction between the fuel gas and the oxidant gas in the power generation section 30. Although the individual cell 12 generates heat due to power generation, it is cooled by a cooling medium flowing in a cooling medium flow path (not shown).

[0039] <The Role of the Implementation Method>

[0040] Next, the function of assembling fuel cell 11 will be explained.

[0041] like Figure 1 and Figure 2As shown, when assembling the fuel cell 11, firstly, multiple individual cells 12 are stacked to form a fuel cell stack 13. Next, the fuel cell stack 13 is clamped from both sides of the stacking direction Z of the individual cells 12 using a first end plate 14a and a second end plate 14b. In this case, a gear 24 is provided at the center of the first outer surface 22 of the first end plate 14a, configured to rotate in both forward and reverse directions around a second axis J2.

[0042] Next, four bolts 16, which are respectively inserted into the four through holes 21 of the second end plate 14b, are inserted into the four through holes 21 of the first end plate 14a. As a result, the shaft portions 18 of the four bolts 16 protrude outwards in the stacking direction Z from the first outer surface 22 of the first end plate 14a. On the other hand, the heads 19 of the four bolts 16 are in contact with the second outer surface 23 of the second end plate 14b.

[0043] Next, the heads 19 of the four bolts 16 are fixed to the second outer surface 23 of the second end plate 14b, for example, by welding. This prevents the four bolts 16 from rotating relative to the through hole 21. Then, four nuts 17 are screwed onto the top ends of the shaft portions 18 of the four bolts 16, which protrude outwards in the stacking direction Z from the first outer surface 22 of the first end plate 14a. At this time, the gear portions 20 of the four nuts 17 directly mesh with a gear 24.

[0044] Next, when a general-purpose tool such as a socket wrench engages with the protrusion 25 of the gear 24, causing the gear 24 to move... Figure 2 When the gear 24 rotates counterclockwise, its rotational force is transmitted to all four nuts 17 simultaneously. That is, the rotational force of the gear 24 is relative to the four nuts 17 in the tightening direction. Figure 2 The clockwise rotational force is transmitted simultaneously.

[0045] Thus, the four nuts 17 are simultaneously tightened under the same prescribed rotational force, thereby uniformly compressing the fuel cell stack 13 in the stacking direction Z through the first end plate 14a and the second end plate 14b. This completes the assembly of the fuel cell 11. In this assembled fuel cell 11, surface pressure can be uniformly applied to each individual cell 12 constituting the fuel cell stack 13. Therefore, the quality of the fuel cell 11 becomes stable.

[0046] Incidentally, if there is a deviation in the surface pressure applied to each cell 12 constituting the fuel cell stack 13 in the fuel cell 11, the power generation performance of the fuel cell 11 will decrease, and thus the quality of the fuel cell 11 will become unstable.

[0047] <Effects of the Implementation Method>

[0048] The implementation method described in detail above can achieve the following effects.

[0049] (1) The fuel cell 11 includes: a fuel cell stack 13 having a plurality of stacked plate-shaped individual cells 12; and a pair of end plates 14. Each individual cell 12 has a power generation section 30 and a pair of partitions 28 for clamping the power generation section 30. The pair of end plates 14 clamp the fuel cell stack 13 from both sides in the stacking direction Z. The fuel cell 11 also includes a plurality of fastening members 15 and a gear 24. The plurality of fastening members 15 are rotatable about their respective independent first axes J1 extending along the stacking direction Z and each has an annular gear portion 20. The plurality of fastening members 15 fasten the pair of end plates 14 together. The gear 24 is configured to be rotatable about a second axis J2 extending along the stacking direction Z and is provided on the first outer surface 22 of the first end plate 14a, which is one of the pair of end plates 14. The gear 24 is configured to mesh with the gear portions 20 of the plurality of fastening members 15 and simultaneously transmit the rotational force in the case of rotation relative to the plurality of fastening members 15 in the tightening direction.

[0050] According to the above structure, by meshing a gear 24 with each gear section 20, the gear 24 is rotated, thereby enabling more reliable transmission of rotational force from one gear 24 to multiple fastening members 15 (nuts 17). Therefore, multiple fastening members 15 can be tightened simultaneously by rotating only one gear 24, thus allowing uniform compression of the fuel cell stack 13 in the stacking direction Z using a pair of end plates 14. Consequently, surface pressure is uniformly applied to each individual cell 12 constituting the fuel cell stack 13, thereby stabilizing the quality of the fuel cell 11.

[0051] (2) In the fuel cell 11, the gear 24 transmits rotational force in direct contact with the gear portion 20 of the plurality of fastening members 15.

[0052] According to the above structure, the rotational force of gear 24 is directly transmitted to multiple fastening members 15 (nuts 17) by rotating gear 24. Therefore, the rotational force of gear 24 can be transmitted to multiple fastening members 15 efficiently.

[0053] (3) In the fuel cell 11, a hexagonal protrusion 25 is formed at the center of the gear 24 for engaging with a general-purpose tool when the gear 24 is rotated.

[0054] Based on the above structure, gear 24 can be rotated using only general-purpose tools without the need for special tools.

[0055] <Example of Change>

[0056] The above-described embodiments can be implemented with modifications as follows. Furthermore, the above-described embodiments and the following modifications can be combined with each other to implement them without technical inconsistencies.

[0057] ·like Figure 4 and Figure 5 As shown, in the fuel cell 11, the positions of the head 19 of the bolt 16 and the nut 17 can also be interchanged. That is, an annular gear portion 20 is integrally formed on the outer edge of the head 19 of the bolt 16. The gear portion 20 of the head 19 of the bolt 16 meshes with the gear 24. The head 19 of the bolt 16 contacts the first outer surface 22 of the first end plate 14a. The tip of the shaft portion 18 of the bolt 16 protrudes outward in the stacking direction Z beyond the second outer surface 23 of the second end plate 14b. The nut 17 is fixed to the second outer surface 23 of the second end plate 14b by welding or the like while engaged with the tip of the shaft portion 18 of the bolt 16. Therefore, the nut 17 cannot rotate. Even with this configuration, the same effect as the above embodiment can be obtained.

[0058] ·like Figure 6 As shown, in the fuel cell 11, the gear portions 20 of the four nuts 17 can also be configured such that they mesh with a gear 24 via a transmission gear 39. In this case, the outer diameters of the gear portions 20 of the nuts 17, the transmission gear 39, and the gear 24 can be appropriately changed.

[0059] In the above Figure 6 In the fuel cell 11, it can also be configured such that the gear section 20 of the four nuts 17 meshes with a gear 24 via a plurality of transmission gears 39.

[0060] ·like Figure 7 As shown, in the fuel cell 11, instead of the gear 24, a circular plate-shaped rotating member 41 with a ring-shaped friction member 40, which has high frictional resistance such as rubber, provided on its outer edge can be used as an example of a rotating body. Furthermore, the gear portion 20 on the outer edge of the nut 17 can be replaced with a ring-shaped friction member 40. In this case, the friction member 40 of each nut 17 contacts the friction member 40 of the rotating member 41. Even with this configuration, the rotational force of the rotating member 41 can be transmitted to each nut 17 through the frictional force between the friction member 40 of each nut 17 and the friction member 40 of the rotating member 41, thus achieving the same effect as the embodiment described above.

[0061] Alternatively, a handle for manually rotating the gear 24 can be provided at the center of the gear 24 instead of the protrusion 25. In this way, the gear 24 can be easily rotated manually even without tools.

[0062] Alternatively, a hexagonal recess can be provided at the center of gear 24 to replace the protrusion 25. This allows gear 24 to be rotated using a hex wrench.

[0063] • In fuel cell 11, a pair of end plates 14 can also be fastened by two fastening members 15, three fastening members 15, or more than five fastening members 15.

[0064] • The end plate 14 is not limited to a square shape; it can also be a polygonal shape such as a triangle or hexagon, or a circle or an ellipse.

Claims

1. A fuel cell, wherein, The fuel cell has the following features: A fuel cell stack has multiple stacked plate-shaped individual cells, and each individual cell has a power generation section and a pair of partitions that hold the power generation section. A pair of end plates clamp the fuel cell stack from both sides of the stacking direction of the individual cells; Multiple fastening members rotate about their respective independent first axes extending along the stacking direction and fasten the pair of end plates together. as well as A rotating body is configured to rotate about a second axis extending along the stacking direction and is disposed on the outer side of either of the pair of end plates in the stacking direction, wherein the rotating body is configured such that rotational force during rotation is simultaneously transmitted relative to rotational force of the plurality of fastening members in the tightening direction.

2. The fuel cell according to claim 1, wherein, The rotating body transmits the rotational force in direct contact with the plurality of fastening members.

3. The fuel cell according to claim 1 or 2, wherein, The rotating body is composed of a gear. Each of the fastening members has an annular gear portion that meshes with the gear.

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