fuel cell

Abstract

This technology provides a way to suppress leaks in fuel cell cells even if a sub-gasket delaminates in an area where no surface pressure is applied. [Solution] The fuel cell cell of the present disclosure comprises at least a first separator, a first gasket, a sub-gasket, a membrane electrode assembly, a second separator, and a second gasket, all of which are stacked, with at least one of the first separator and the second separator being a flow channel separator, and a sealed space formed by the sub-gasket being folded back at the end of the flow channel separator, where a sealed space is formed between the sub-gasket and the flow channel separator that blocks reaction gas toward the end.

Description

Technical Field

[0001] The present disclosure relates to fuel cell.

Background Art

[0002] Techniques for ensuring sealing performance in fuel cells are known.

[0003] For example, Patent Document 1 discloses a gasket having a plate, a covering portion made of a rubber-like elastic body covering the peripheral edge portion of the plate, and a seal lip provided on the plane of the covering portion, wherein a recess which is a plate holding mark during gasket forming is formed on the plane of the covering portion on the outer peripheral side of the seal lip, and a second seal lip is provided on the plane of the covering portion on the further outer peripheral side of the recess. Patent Document 1 discloses that, in order to ensure the sealing performance as a gasket, both surfaces in the thickness direction and the outer peripheral thickness surface of the peripheral edge portion of the separator are covered with a covering portion made of a rubber-like elastic body, and a seal lip is integrally provided on the plane of the covering portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, the sub-gaskets that make up fuel cell cells are made of materials that are difficult to bond. Also, because the sub-gaskets are made of thin material, they expand when pressure is applied. Therefore, depending on the pressure difference between the anode gas and the cathode gas, the parts of the sub-gasket that are not subjected to surface pressure may peel off, causing leaks. Although the technology disclosed in Patent Document 1 can ensure the sealing performance of the gasket, there is room for improvement in suppressing such leaks.

[0006] In light of these circumstances, the purpose of this disclosure is to provide a technology that suppresses leakage in a fuel cell cell even when a portion of the sub-gasket that is not subjected to surface pressure peels off. [Means for solving the problem]

[0007] A fuel cell according to one embodiment of the present disclosure is a fuel cell cell comprising at least a first separator, a first gasket, a sub-gasket, a membrane electrode assembly, a second separator, and a second gasket, which are stacked together, wherein at least one of the first separator and the second separator is a separator with a flow path, and the sub-gasket is folded back at the end of the separator with a flow path to form a sealed space, between the sub-gasket and the separator with a flow path to block reaction gas toward the end. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, even if a portion of the sub-gasket that is not subjected to surface pressure peels off, leakage in the fuel cell can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a vehicle equipped with a fuel cell cell according to one embodiment of the present disclosure. [Figure 2] This is an exploded perspective view showing a schematic configuration of a fuel cell cell according to one embodiment of the present disclosure. [Figure 3] This is a plan view showing a part of a fuel cell cell related to a comparative example. [Figure 4] This is a portion of the AA cross-sectional view shown in Figure 3. [Figure 5] This diagram illustrates a leak that occurs when the sub-gasket detaches. [Figure 6] This is a portion of the BB cross-section shown in Figure 3. [Figure 7] This diagram illustrates the leaks that occur when the sub-gasket detaches. [Figure 8] This is a plan view showing a portion of a fuel cell cell according to the first embodiment of this disclosure. [Figure 9] This is a portion of the cross-sectional view of CC shown in Figure 8. [Figure 10] This is a cross-sectional view showing a portion of a fuel cell cell according to a second embodiment of the present disclosure. [Figure 11] This is a cross-sectional view showing a portion of a fuel cell cell according to a third embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described below with reference to the attached drawings.

[0011] <1. First Embodiment> (1-1. General configuration of the vehicle) Referring to Figure 1, the vehicle 1 in this embodiment comprises at least a fuel cell stack 2, an inverter 3, a load 4, and a control device 5. In the vehicle 1, under the control of the control device 5, the electricity generated by the fuel cell stack 2 is supplied to the load 4 via the inverter 3. The vehicle 1 also includes known equipment (not shown) that is installed in fuel cell vehicles, such as a hydrogen tank, an anode gas supply device, a cathode gas supply device, a refrigerant supply device, and a DC / DC converter.

[0012] The fuel cell stack 2 is configured by stacking, for example, several tens to several hundreds of fuel cells 100 described later. Each fuel cell 100 has a function of generating electricity by reacting an anode gas and a cathode gas. The fuel cell stack 2 may include a known voltage sensor 6 capable of measuring the voltage applied to each fuel cell 100. Further, the fuel cell stack 2 may include a known current sensor 7 capable of measuring the current flowing through the fuel cell 100. The fuel cell 100 is not particularly limited, and may be, for example, a known polymer electrolyte fuel cell (PEFC: Polymer Electrolyte Fuel Cell) or the like.

[0013] The inverter 3 has a function of converting DC power obtained by boosting, for example, by a DC / DC converter, into AC power suitable for driving the load 4. The inverter 3 is not particularly limited as long as it exhibits the above-described function, and for example, a known inverter including a three-phase bridge circuit can be applied.

[0014] The load 4 includes, for example, a known electric motor capable of outputting power for driving the drive wheels of the vehicle 1. The electric motor is, for example, a known three-phase AC electric motor. The load 4 may be other electrical equipment mounted on the vehicle 1.

[0015] The control device 5 is a known ECU (Electronic Control Unit) mounted on the fuel cell vehicle. The control device 5 includes a processor such as one or more CPUs (Central Processing Unit), and one or more memories such as semiconductor memories, magnetic memories, or optical memories communicably connected to the processor. The control device 5 may further include a known BMU (Battery Management Unit) that monitors and controls the state of the battery. The control device 5 may be communicably configured with other known EUCs and various sensors (not shown) mounted on the vehicle 1.

[0016] (1-2. Schematic Configuration of Fuel Cell) Referring to FIG. 2, the overall configuration of the fuel cell 100 applicable to the fuel cell stack 2 provided in the vehicle 1 will be briefly described. The fuel cell 100 includes at least a first separator 10, a first gasket 20, a sub-gasket 30, a membrane electrode assembly 40, a second separator 50, and a second gasket 60, which are laminated.

[0017] In the present embodiment, at least one of the first separator 10 and the second separator 50 is a separator with flow channels. Hereinafter, the case where the first separator 10 is a flat separator and the second separator 50 is a separator with flow channels will be described as an example, but the present disclosure is not limited thereto.

[0018] (1-2-1. First Separator) The first separator 10 is, for example, a rectangular flat separator. On the surface of the first separator 10 facing the membrane electrode assembly 40, one of the anode gas and the cathode gas flows. Through holes MF1 for the cooling water manifold and through holes MF2 and MF3 for the gas manifold are appropriately formed in the first separator 10.

[0019] The first separator 10 may be, for example, a metal separator made of known aluminum, stainless steel or titanium, or may be a carbon separator made of a known carbon-based material, etc. However, the material of the first separator 10 is not limited thereto.

[0020] (1-2-2. First Gasket) The first gasket 20 has, for example, a rectangular outer shape corresponding to the first separator 10. Through holes MF1 for the cooling water manifold and through holes MF2 and MF3 for the gas manifold are appropriately formed in the first gasket 20 so as to correspond to the first separator 10.

[0021] The first gasket 20 may be made of a sealing material such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or a synthetic resin material such as silicone resin. However, the material of the first gasket 20 is not limited to these.

[0022] (1-2-3. Sub-gasket) The sub-gasket 30 has an outer shape, for example, rectangular, corresponding to the first separator 10 and the first gasket 20. The sub-gasket 30 has through holes MF1 for the cooling water manifold and through holes MF2 and MF3 for the gas manifold, appropriately formed to correspond to the first separator 10 and the first gasket 20. The sub-gasket 30 also has a housing space formed in the center where the membrane electrode assembly 40 is placed. The sub-gasket 30 mainly performs the function of sealing the area where the membrane electrode assembly 40 is placed.

[0023] The sub-gasket 30 may be made of a sealing material such as a synthetic resin material such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or polyphenylene sulfide (PPS). However, the material of the sub-gasket 30 is not limited to these.

[0024] (1-2-4. Membrane electrode assembly) The membrane electrode assembly 40 is attached to the housing space formed in the sub-gasket 30. The membrane electrode assembly 40 may be a known or any membrane electrode assembly comprising an electrolyte layer (not shown) sandwiched between a pair of catalyst layers (not shown) and a pair of gas diffusion layers (not shown).

[0025] (1-2-5. Second separator) The second separator 50 is a separator with a flow path, having at least an uneven structure for forming, for example, a gas flow path and a cooling water flow path. The second separator 50 has, for example, a rectangular outer shape corresponding to the first separator 10, the first gasket 20, and the sub-gasket 30. On the side of the second separator 50 facing the membrane electrode assembly 40, the other of the anode gas and cathode gas flows. On the side of the second separator 50 opposite the membrane electrode assembly 40, cooling water flows.

[0026] The second separator 50 has through holes MF1 for the cooling water manifold and through holes MF2 and MF3 for the gas manifold appropriately formed to correspond to the first separator 10, the first gasket 20, and the sub-gasket 30.

[0027] The second separator 50 may be a metal separator made of, for example, known aluminum, stainless steel, or titanium. However, the material of the second separator 50 is not limited to these.

[0028] (1-2-6. Second gasket) The second gasket 60 has an outer shape, for example, rectangular, corresponding to the first separator 10, the first gasket 20, the sub-gasket 30, and the second separator 50. The second gasket 60 has through holes MF1 for the cooling water manifold and through holes MF2 and MF3 for the gas manifold, appropriately formed to correspond to the first separator 10, the first gasket 20, the sub-gasket 30, and the second separator 50.

[0029] The second gasket 60 may be made of a sealing material such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), olefin resin, synthetic rubber resin, or silicone resin. However, the material of the second gasket 60 is not limited to these.

[0030] (1-3. Comparative Examples) Before describing in detail the configuration of the fuel cell cell 100 according to the first embodiment of this disclosure, a comparative example fuel cell cell 100' that the inventors considered when conceiving this embodiment will be described.

[0031] Referring to Figures 3 and 4, in the fuel cell cell 100', in cross-section AA, cathode gas CG flows between the plate separator 10' and the sub-gasket 30' in the direction of the arrow. Also, anode gas AG flows perpendicular to the plane of the paper on the side of the flowing separator 50' facing the sub-gasket 30'. Furthermore, cooling water CW flows perpendicular to the plane of the paper on the side of the flowing separator 50' facing the adjacent plate separator 10'.

[0032] Referring to Figure 5, when the pressure of the anode gas AG becomes higher than the pressure of the cathode gas CG, in cross-sections where the first gasket 20 is absent, such as cross-section AA, no surface pressure is applied to the sub-gasket 30', and the sub-gasket 30' separates from the flow-through separator 50'. As a result, the anode gas AG flows out between the sub-gasket 30' and the flow-through separator 50' in the direction of the arrow, causing a leak.

[0033] Referring to Figures 3 and 7, in the BB cross-section of the fuel cell cell 100', cathode gas CG flows perpendicular to the plane of the paper through the region enclosed by the flat plate separator 10', sub-gasket 30', and cathode gasket 20'. Referring to Figure 3, when the differential pressure between anode gas AG and cathode gas CG becomes large, the portion of sub-gasket 30' directly above the cathode gas CG flow path where no surface pressure is applied peels off. As a result, anode gas AG leaks.

[0034] While it is desirable to suppress the delamination described above, it is difficult to suppress such delamination because the sub-gasket 30' is generally made of a material that is difficult to adhere to. Therefore, even if delamination occurs in areas of the sub-gasket 30' where no surface pressure is applied, it is necessary to suppress the leakage described above. The embodiment described below was conceived with this problem in mind.

[0035] (1-4. Example of fuel cell configuration) The fuel cell cell 100 according to the first embodiment is formed by laminating at least a flat plate separator which is an example of a first separator 10, a first gasket 20, a sub-gasket 30, a membrane electrode assembly 40, a separator with a flow path which is an example of a second separator 50, and a cooling water gasket which is an example of a second gasket 60.

[0036] Referring to Figures 8 and 9, in the first embodiment, the sub-gasket 30 is folded back at the end 51 of a flow-channel separator, which is an example of the second separator 50. Note that Figure 8 is illustrated without the sub-gasket 30. As a result, a sealed space 70 is formed between the sub-gasket 30 and the flow-channel separator, blocking the reaction gas toward the end 51 of the flow-channel separator.

[0037] This sealed space 70 prevents the reaction gas from leaking even if, for example, a portion of the sub-gasket 30' that is not subjected to surface pressure peels off, as shown in Figure 5. Therefore, leakage in the fuel cell cell 100 can be suppressed. The components constituting the sealed space 70 in the first embodiment will now be described in detail.

[0038] (1-4-1. Example of sub-gasket configuration) The sub-gasket 30 includes a main body 31 and a folded portion 32. The main body 31 is aligned with a flow-type separator, which is an example of a second separator 50, and forms the main surface of the sub-gasket 30. The folded portion 32 is continuous with the main body 31 and is folded back at the end 51 of the flow-type separator. More specifically, the folded portion 32 includes a curved portion 33 that is continuous with the main body 31 and has, for example, a U-shaped cross-section, and a folded end portion 34 that is continuous with the curved portion 33 and faces the main body 31 and has, for example, a rectangular cross-section. Therefore, the main body 31 and the folded end portion 34 are spaced apart along the z-direction, which corresponds to the stacking direction of the fuel cell cell 100.

[0039] Referring to Figure 8, the end portion 51 of the separator with a flow path in this embodiment may be the periphery of the separator with a flow path and its vicinity, for example, including a region that is in contact with the through-hole MF3 and overlaps with the inlet of the channel 21 through which cathode gas flows from the through-hole MF3 toward the center of the cell. However, the disclosure is not limited thereto, and the end portion 51 of the separator with a flow path may also be the periphery of the separator and its vicinity, including a region that overlaps with the outlet of the channel 21.

[0040] The bending radius of the curved portion 33 is not particularly limited, but can be appropriately determined considering the height position of the folded end portion 34 and the thickness of the support material 80, which will be described later.

[0041] The height position of the main surface 34s of the folded end portion 34 on the side adjacent to the first separator 10 may be the same as or substantially the same as the height position of the main surface 60s of the second gasket 60 on the side adjacent to the first separator 10. This allows the components constituting the fuel cell cell 100 to be stacked stably. Note that "height position" means, for example, the distance from the first separator 10 along the z-direction, which corresponds to the stacking direction of the fuel cell cell 100.

[0042] (1-4-2. Example of support material configuration) The fuel cell cell 100 further includes a support material 80 sandwiched together with the end 51 of a flow-channel separator, which is an example of a second separator 50, by the main body 31 and the folded portion 32 of the sub-gasket 30. In the example shown in Figure 9, the support material 80 is sandwiched together with the end 51 of the flow-channel separator by the main body 31 and the folded portion 34. This allows the main body 31 and the folded portion 34 to be spaced further apart along the z-direction, which corresponds to the stacking direction of the fuel cell cell 100, compared to the third embodiment described later. Therefore, the stress caused by bending, particularly on the curved portion 33 of the sub-gasket 30, can be reduced.

[0043] In the examples shown in Figures 8 and 9, the support material 80 has a CC cross-section that is, for example, rectangular, and extends along the x-direction corresponding to the extension direction of the end portion 51 of the flow channel separator, which is an example of the second separator 50. The term "CC cross-section" refers to the yz cross-section, which corresponds to the cross-section perpendicular to the x-direction corresponding to the extension direction of the end portion 51 of the flow channel separator, which is an example of the second separator 50.

[0044] The thickness of the support material 80 can be appropriately determined such that the height position of the main surface 34s on the side of the folded end 34 adjacent to the first separator 10 and the height position of the main surface 60s on the side of the second gasket 60 adjacent to the first separator 10 are the same or substantially the same.

[0045] The support material 80 may be made of the same material as the second gasket 60. That is, the support material 80 may be made of, for example, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or a synthetic resin material such as silicone resin. However, the material of the support material 80 is not limited to these.

[0046] (1-4-3. Examples of enclosed space configurations) The sealed space 70 is formed as a space defined by at least the folded portion 32 of the sub-gasket 30, the end portion 51 of the flow-through separator, which is an example of the second separator 50, and the support material 80. In the example shown in Figure 9, the sealed space 70 is defined by the curved portion 33 and part of the folded end portion 34 of the sub-gasket 30, part of the end portion 51 of the flow-through separator, and the side surface of the support material 80.

[0047] The sealed space 70 may be filled with liquid gasket. This improves the sealing performance. However, the liquid gasket does not need to be filled throughout the entire sealed space 70. In the example shown in Figure 8, the liquid gasket may be filled only at both ends 51a and 51b in the x-direction corresponding to the extending direction of the end 51 of the flow channel separator, which is an example of the second separator 50.

[0048] The liquid gasket may be made of the same material as the second gasket 60. In this case, the liquid gasket may be made of synthetic resin materials such as olefin resin, synthetic rubber resin, or silicone resin, similar to the second gasket 60.

[0049] (1-5. Examples of fuel cell cell manufacturing methods) The method for manufacturing the fuel cell cell 100 is not particularly limited, but may include repeating the following steps 1 through 4.

[0050] In other words, in the first step, the first separator 10, the first gasket 20, the sub-gasket 30, and the second separator 50 are stacked. In the second step, the support material 80 is placed. In the third step, liquid gasket is optionally filled in. In the fourth step, the portion of the sub-gasket 30 corresponding to the folded portion 32 is folded back and comes into contact with the support material 80, forming a sealed space 70. As can be understood from this manufacturing method, the support material 80 is pressed along the z-direction corresponding to the stacking direction of the fuel cell cell 100 by the adjacent first separator 10 via the folded portion 32 of the sub-gasket 30, so it does not need to be fixed with adhesive or the like.

[0051] (1-6. Summary) As described above, in the fuel cell cell 100 according to the first embodiment, the sub-gasket 30 includes a main body portion 31 along the flow-flow separator and a folded portion 32 that is continuous with the main body portion 31 and folded back at the end portion 51 of the flow-flow separator. The fuel cell cell 100 also further includes a support material 80 that is sandwiched together with the end portion 51 of the flow-flow separator by the main body portion 31 and the folded portion 32 of the sub-gasket 30. Furthermore, a sealed space 70 is formed, defined by at least the folded portion 32 of the sub-gasket 30, the end portion 51 of the flow-flow separator, and the support material 80.

[0052] With this configuration, even if a portion of the sub-gasket 30 that is not subjected to surface pressure peels off, the reaction gas is blocked by the sealed space 70. Therefore, leakage in the fuel cell cell 100 can be suppressed. In addition, the support material 80 can separate the main body portion 31 and the folded portion 32 of the sub-gasket 30. Therefore, the load on the sub-gasket 30 can also be reduced.

[0053] <2. Second Embodiment> (2-1. Example of fuel cell configuration) The fuel cell cell 200 according to the second embodiment is formed by laminating at least a flat plate separator which is an example of the first separator 10, a first gasket 20, a sub-gasket 30, a membrane electrode assembly 40, a separator with a flow path which is an example of the second separator 50, and a cooling water gasket which is an example of the second gasket 60.

[0054] Referring to Figure 10, in the second embodiment, the sub-gasket 30 is folded back at the end 51 of a flow-channel separator, which is an example of the second separator 50. This creates a sealed space 70 between the sub-gasket 30 and the flow-channel separator that blocks the reaction gas toward the end 51 of the flow-channel separator.

[0055] This sealed space 70 prevents the reaction gas from leaking even if, for example, a portion of the sub-gasket 30' that is not subjected to surface pressure peels off, as shown in Figure 5. Therefore, leakage in the fuel cell cell 200 can be suppressed. The components constituting the sealed space 70 in the second embodiment will be described in detail below. However, the differences from the first embodiment will be described in detail, and the others will be described briefly.

[0056] (2-1-1. Example of sub-gasket configuration) The sub-gasket 30 includes a main body 31 and a folded portion 32. The main body 31 follows a flow-flow separator, which is an example of a second separator 50. The folded portion 32 is continuous with the main body 31 and is folded back at the end 51 of the flow-flow separator. More specifically, the folded portion 32 includes a curved portion 33 that is continuous with the main body 31 and has, for example, a U-shaped cross-section, and a folded end portion 34 that is continuous with the curved portion 33 and faces the main body 31 and has, for example, a rectangular cross-section. Therefore, the main body 31 and the folded end portion 34 are spaced apart along the z-direction, which corresponds to the stacking direction of the fuel cell cells 200.

[0057] The height position of the main surface 34s of the folded end portion 34 on the side adjacent to the first separator 10 may be the same as or substantially the same as the height position of the main surface 60s of the second gasket 60 on the side adjacent to the first separator 10. This allows the components constituting the fuel cell cell 200 to be stacked stably. The bending radius of the curved portion 33 is not particularly limited, but can be appropriately determined considering the height position of the folded end portion 34 and the shape of the support portion 52 described later.

[0058] (2-1-2. Example of Support Unit Configuration) An example of a second separator 50, the end portion 51 of the separator with a flow path, further includes a support portion 52 formed by bending the separator with a flow path so as to support the folded portion 32 of the sub-gasket 30. More specifically, the end portion 51 of the separator with a flow path further includes a support portion 52 formed by bending the separator with a flow path so as to support the folded end portion 34 of the folded portion 32.

[0059] As a result, the main body portion 31 and the folded portion 32 of the sub-gasket 30 can be spaced further apart along the z-direction, which corresponds to the stacking direction of the fuel cell 200, compared to the third embodiment described later. Therefore, the stress caused by bending, particularly on the curved portion 33 of the sub-gasket 30, can be reduced. Furthermore, since the separator with a flow path includes a support portion 52, the number of components constituting the fuel cell 200 can be reduced compared to the first embodiment. In addition, when stacking the components constituting the fuel cell 200, the positioning process for support material 80, etc., can be omitted.

[0060] In the example shown in Figure 10, the support portion 52 includes an inclined portion 54 that is continuous with the main body portion 53 of the separator with a flow path and is inclined toward the second gasket 60 side relative to the main body portion 53, and a support end portion 55 that is continuous with the inclined portion 54 and supports the folded end portion 34, for example, having a rectangular cross-section. The thickness of the inclined portion 54 and the support end portion 55 is not particularly limited, but may be the same as that of the main body portion 53. The main body portion 53 of the separator with a flow path is, for example, the portion sandwiched between the main body portion 31 of the sub-gasket 30 and the second gasket 60. Figure 10 also shows a CC cross-section similar to that in Figure 8.

[0061] The inclination angle of the inclined portion 54 can be appropriately determined such that the height position of the main surface 34s on the side of the folded end portion 34 adjacent to the first separator 10 and the height position of the main surface 60s on the side of the second gasket 60 adjacent to the first separator 10 are the same or substantially the same. However, the shape of the support portion 52 is not limited to the example shown in Figure 10, as long as it can support the folded portion 32 of the sub-gasket 30. The support portion 52 can be formed, for example, by known or arbitrary bending processes when manufacturing a separator with a flow path, which is an example of the second separator 50, but is not limited thereto.

[0062] (2-1-3. Examples of enclosed space configurations) The sealed space 70 is formed as a space defined by the main body portion 31, the folded portion 32, and the support portion 52 of the sub-gasket 30. In the example shown in Figure 10, the sealed space 70 is defined by the main body portion 31 and the curved portion 33 of the sub-gasket 30, and the inclined portion 54 and support end portion 55 of the support portion 52.

[0063] Furthermore, the sealed space 70 may be filled with liquid gasket, as in the first embodiment. This improves the sealing performance. However, as in the first embodiment, the liquid gasket does not need to be filled throughout the entire sealed space 70.

[0064] (2-2. Examples of fuel cell manufacturing methods) The method for manufacturing the fuel cell cell 200 is not particularly limited, but may include repeating the following first to third steps.

[0065] In other words, in the first step, the first separator 10, the first gasket 20, the sub-gasket 30, and the second separator 50 are stacked. Here, a support portion 52 is pre-formed in a separator with a flow path, which is an example of the second separator 50. In the second step, liquid gasket is optionally filled in. In the third step, the portion of the sub-gasket 30 corresponding to the folded portion 32 is folded back and comes into contact with the support portion 52, forming a sealed space 70.

[0066] (2-3. Summary) As described above, in the fuel cell cell 200 according to the second embodiment, the sub-gasket 30 includes a main body portion 31 along the flow-flow separator and a folded portion 32 that is continuous with the main body portion 31 and folded back at the end portion 51 of the flow-flow separator. The end portion 51 of the flow-flow separator further includes a support portion 52 formed by bending the flow-flow separator to support the folded portion 32 of the sub-gasket 30. The sealed space 70 is formed as a space defined by the main body portion 31, the folded portion 32, and the support portion 52 of the sub-gasket 30.

[0067] With this configuration, even if a portion of the sub-gasket 30 that is not subjected to surface pressure peels off, the reaction gas is blocked by the sealed space 70. Therefore, leakage in the fuel cell cell 200 can be suppressed. In addition, the support portion 52 can separate the main body portion 31 and the folded portion 32 of the sub-gasket 30. Therefore, the load on the sub-gasket 30 can also be reduced. Furthermore, the end portion 51 of the separator with a flow path includes the support portion 52. Therefore, the number of parts constituting the fuel cell cell 200 can be reduced compared to the first embodiment, and the positioning process can be omitted when stacking the parts constituting the fuel cell cell 200.

[0068] <3. Third Embodiment> (3-1. Example of fuel cell configuration) The fuel cell cell 300 according to the third embodiment is formed by laminating at least a flat plate separator which is an example of a first separator 10, a first gasket 20, a sub-gasket 30, a membrane electrode assembly 40, a separator with a flow path which is an example of a second separator 50, and a cooling water gasket which is an example of a second gasket 60.

[0069] Referring to Figure 11, in the third embodiment, the sub-gasket 30 is folded back at the end 51 of a flow-channel separator, which is an example of the second separator 50. This makes it possible to form a sealed space 70 between the sub-gasket 30 and the flow-channel separator, which is an example of the second separator 50, which blocks the reaction gas toward the end 51 of the flow-channel separator.

[0070] This sealed space 70 prevents the reaction gas from leaking even if, for example, a portion of the sub-gasket 30' that is not subjected to surface pressure peels off, as shown in Figure 5. Therefore, leakage in the fuel cell cell 300 can be suppressed. The components constituting the sealed space 70 in the third embodiment will be described in detail below. However, the differences from the first embodiment will be described in detail, and the others will be described briefly.

[0071] (3-1-1. Example of sub-gasket configuration) The sub-gasket 30 includes a main body portion 31 and a folded portion 32. The main body portion 31 follows a flow-flow separator, which is an example of the second separator 50. The folded portion 32 is continuous with the main body portion 31 and is folded back at the end portion 51. More specifically, the folded portion 32 includes a curved portion 33 that is continuous with the main body portion 31 and has, for example, a U-shaped cross-section, and a folded end portion 34 that is continuous with the curved portion 33 and faces the main body portion 31 and has, for example, a rectangular cross-section. Unlike the first and second embodiments, the end portion 51 of the flow-flow separator is sandwiched only by the main body portion 31 and the folded end portion 34.

[0072] (3-1-2. Examples of enclosed space configurations) The sealed space 70 is formed as a space defined at least by the folded portion 32 of the sub-gasket 30 and the end portion 51 of the separator with a flow path, and is filled with liquid gasket. This improves the sealing performance. Also, since the main body portion 31 and the folded portion 32 of the sub-gasket 30 are not as far apart as in the first and second embodiments, the volume of liquid gasket can be reduced. Note that, as in the first embodiment, the entire sealed space 70 does not need to be filled with liquid gasket.

[0073] (3-1-3. Example of fastening material configuration) The fuel cell cell 300 further includes a pressing material 90 that presses the folded portion 32 of the sub-gasket 30 against the end portion 51 of the separator with a flow path.

[0074] In the example shown in Figure 11, the retaining material 90 has a CC cross-section that is, for example, rectangular, and extends along the x-direction corresponding to the extending direction of the end 51 of the flow-flow separator, which is an example of the second separator 50. The thickness of the retaining material 90 can be appropriately determined such that the height position of the main surface 90s of the retaining material 90 on the adjacent first separator 10 side is the same as or substantially the same as the height position of the main surface 60s of the second gasket 60 on the adjacent first separator 10 side. The material of the retaining material 90 may be the same as that of the support material 80 in the first embodiment.

[0075] (3-2. Examples of fuel cell cell manufacturing methods) The method for manufacturing the fuel cell cell 300 is not particularly limited, but may include repeating the following steps 1 through 4.

[0076] In other words, in the first step, the first separator 10, the first gasket 20, the sub-gasket 30, and the second separator 50 are stacked. In the second step, liquid gasket is filled. In the third step, the portion of the sub-gasket 30 corresponding to the folded portion 32 is folded back and contacts the end portion 51 of the separator with a flow path, forming a sealed space 70. In the fourth step, a pressing material 90 is placed. As can be understood from this manufacturing method, the pressing material 90 is pressed by the adjacent first separator 10 along the z-direction corresponding to the stacking direction of the fuel cell cell 300, so it does not need to be fixed with adhesive or the like.

[0077] (3-3. Summary) As described above, in the fuel cell cell 300 according to the third embodiment, the sub-gasket 30 includes a main body portion 31 along the flow-flow separator and a folded portion 32 that is continuous with the main body portion 31 and folded back at the end portion 51 of the flow-flow separator. The fuel cell cell 300 also further includes a pressing member 90 that presses the folded portion 32 of the sub-gasket 30 against the end portion 51 of the flow-flow separator. Furthermore, the sealed space 70 is formed as a space defined at least by the folded portion 32 of the sub-gasket 30 and the end portion 51 of the flow-flow separator, and is filled with liquid gasket.

[0078] With this configuration, even if a portion of the sub-gasket 30 that is not subjected to surface pressure peels off, the reaction gas is blocked by the sealed space 70. Therefore, leakage in the fuel cell cell 300 can be suppressed. In addition, since the main body portion 31 and the folded portion 32 of the sub-gasket 30 are not as far apart as in the first and second embodiments, the volume of liquid gasket can be reduced.

[0079] While embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the present disclosure is not limited to such examples. It is clear that a person with ordinary skill in the art to which the present disclosure belongs can conceive of various modifications or alterations within the scope of the technical idea described in the claims, and these are also understood to fall within the technical scope of the present disclosure. For example, the functions included in each component can be rearranged in a logically consistent manner, and multiple components can be combined into one or separated.

[0080] Furthermore, the technology disclosed herein can also be realized as a vehicle 1 equipped with any of the fuel cell cells 100, 200, or 300 according to the first to third embodiments described above. [Explanation of symbols]

[0081] 1: Vehicle, 2: Fuel cell stack, 3: Inverter, 4: Load, 5: Control device, 6: Voltage sensor, 7: Current sensor, 100, 200, 300: Fuel cell cells, 10: First separator, 20: First gasket, 30: Sub-gasket, 31: Main body, 32: Folded part, 40: Membrane electrode assembly, 50: Second separator, 51: End part, 52: Support part, 60: Second gasket, 70: Sealed space, 80: Support material, 90: Retaining material

Claims

1. A fuel cell comprising at least a first separator, a first gasket, a sub-gasket, a membrane electrode assembly, a second separator, and a second gasket, stacked together, At least one of the first separator and the second separator is a separator with a flow path, A sealed space is formed at the end of the separator with a flow path by folding back the sub-gasket, wherein a sealed space is formed between the sub-gasket and the separator with a flow path that blocks the reaction gas toward the end. Fuel cell.

2. The sub-gasket includes a main body portion along the flow-flow separator and a folded portion that is continuous with the main body portion and folded back at the end, The system further comprises a support material that is sandwiched together with the end portion by the main body portion and the folded portion, The sealed space is formed as a space defined by at least the folded portion, the end portion, and the support material. The fuel cell cell according to claim 1.

3. The sub-gasket includes a main body portion along the flow-flow separator and a folded portion that is continuous with the main body portion and folded back at the end, The end of the separator with a flow channel further includes a support portion formed by bending the separator with a flow channel so as to support the folded portion, The sealed space is formed as a space defined by the main body, the folded portion, and the support portion. The fuel cell cell according to claim 1.

4. The aforementioned sealed space is filled with liquid gasket. The fuel cell cell according to claim 2 or 3.

5. The sub-gasket includes a main body portion along the flow-flow separator and a folded portion that is continuous with the main body portion and folded back at the end, The system further includes a pressing member for pressing the folded portion against the end, The sealed space is formed as a space defined at least by the folded portion and the end portion, and is filled with a liquid gasket. The fuel cell cell according to claim 1.

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