Fuel cell unit
By setting flow path sections and ribs on the separator and setting grooves at the connection between the side and the ribs, the problem of water retention is solved, and efficient drainage and power generation performance of the fuel cell unit are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2025-11-25
- Publication Date
- 2026-05-29
AI Technical Summary
Water retention in fuel cell units hinders the flow of reactant gases, leading to reduced power generation performance.
A flow path and a rib are provided on the separator, and a groove is provided at the connection between the side and the rib to discharge the generated water.
The improved drainage performance of the fuel cell unit ensures smooth flow of reaction gases and enhances power generation efficiency.
Smart Images
Figure CN122117952A_ABST
Abstract
Description
[0001] Cross-references to related applications
[0002] This application claims priority based on Japanese Patent Application No. 2024-208396, filed on November 29, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field
[0003] This disclosure relates to fuel cell units. Background Technology
[0004] Various technologies related to the structure of fuel cell units have been proposed. For example, Japanese Patent Application Publication No. 2007-194041 discloses a separator with irregular portions for the flow of reactant gas. In this separator, by bending the protrusions constituting the irregular portions in the thickness direction, the drainage performance of generated water accumulated between the protrusions and the gas diffusion layer is improved.
[0005] The retention of generated water in fuel cell units hinders the flow of reactant gases, potentially reducing power generation performance. Further improvements in drainage performance are required.
[0006] Problem-solving methods
[0007] This invention can be implemented in the following ways.
[0008] According to one aspect of the present invention, a fuel cell unit is provided, comprising: a membrane electrode assembly; a pair of gas diffusion layers disposed such that they sandwich the membrane electrode assembly; and a pair of spacers disposed such that they sandwich the pair of gas diffusion layers. At least one of the pair of spacers has, on a surface facing the gas diffusion layers: a flow path for the passage of reactant gases; and a rib disposed adjacent to the flow path and in contact with the gas diffusion layers. The flow path has a bottom surface separated from the gas diffusion layers and a side portion connecting the bottom surface and the rib. A groove is provided on the side portion extending from the connection portion between the side portion and the rib toward the bottom surface. Attached Figure Description
[0009] Figure 1 This is a perspective view of a fuel cell unit using one aspect of the present invention.
[0010] Figure 2 This is a plan view of the partition.
[0011] Figure 3 In the context of Figure 2 A cross-sectional view of the fuel cell unit cut off at the position corresponding to line III-III.
[0012] Figure 4This is a perspective view of the separator used in the fuel cell unit of the second embodiment.
[0013] Figure 5 This is a perspective view of the separator used in the fuel cell unit of the third embodiment.
[0014] Figure 6 This is a perspective view of the separator for the fuel cell unit in the fourth embodiment. Detailed Implementation
[0015] A. First implementation method:
[0016] <Structure of fuel cell unit 100>
[0017] Figure 1 This is a perspective view of a fuel cell unit 100 using one embodiment of the present invention. Figure 1 The diagram shows the mutually orthogonal X-axis, Y-axis, and Z-axis. Figure 2 This is a plan view of separator 200. Figure 2 The flow path 210 and rib 220, described later, are schematically enlarged on the lower side. Figure 3 In the context of Figure 2 A cross-sectional view of the fuel cell unit 10 cut off at the position corresponding to line III-III. The fuel cell unit 100 is used, for example, as a power source for an electric vehicle. Figure 1 As shown, the fuel cell unit 100 includes a unit stack 110 and a pair of terminal blocks 120 and 130.
[0018] The unit stack 110 is composed of multiple fuel cell units 10 stacked in the Z direction. Each fuel cell unit 10 is a solid polymer fuel cell that generates electricity using reactant gases. The reactant gases are, for example, oxygen as an oxidant gas and hydrogen as a fuel gas. Each fuel cell unit 10 has a rectangular plate-like shape. Detailed structure of the fuel cell unit 10 will be described later.
[0019] A pair of terminal blocks 120 and 130 are respectively disposed at both ends of the stacking direction of the unit stack 110. Each terminal block 120 and 130 is made of conductive materials such as aluminum and copper. Each terminal block 120 and 130 is used to extract the power generated by the fuel cell unit 10 to the outside.
[0020] The fuel cell unit 10 includes oxidant gas manifolds 11a and 11b, refrigerant manifolds 12a and 12b, and fuel gas manifolds 13a and 13b. These manifolds are formed by manifold holes formed on the terminal blocks 120 and 130 and the separator 200 (described later). Oxidant gas manifold 11a supplies oxidant gas to the fuel cell unit 10. Oxidant gas manifold 11b discharges oxidant gas from the fuel cell unit 10. Refrigerant manifold 12a supplies refrigerant to the fuel cell unit 10. Refrigerant manifold 12b discharges refrigerant from the fuel cell unit 10. Fuel gas manifold 13a supplies fuel gas to the fuel cell unit 10. Fuel gas manifold 13b discharges fuel gas from the fuel cell unit 10.
[0021] <Structure of fuel cell unit 10>
[0022] like Figure 3 As shown, the fuel cell unit 10 includes a membrane electrode assembly 300, a pair of gas diffusion layers 400 disposed therebetween to sandwich the membrane electrode assembly 300, and a pair of spacers 200 disposed therebetween to sandwich the pair of gas diffusion layers 400.
[0023] The membrane electrode assembly 300 comprises an electrolyte membrane, an anode catalyst layer bonded to one side of the electrolyte membrane, and a cathode catalyst layer bonded to the other side of the electrolyte membrane. The electrolyte membrane is a solid polymer membrane with proton conductivity. For example, it is an ion-exchange membrane made of a fluorinated resin. The anode catalyst layer contains a catalyst that promotes the chemical reaction of the fuel gas and carbon particles supported on the catalyst. The cathode catalyst layer contains a catalyst that promotes the chemical reaction of the oxidant gas and carbon particles supported on the catalyst.
[0024] The gas diffusion layer 400 uniformly diffuses the reactant gas flowing in the flow path 210 (described later) into the membrane electrode assembly 300. The gas diffusion layer 400 is composed of a porous material. The porous material is made of, for example, a metal or carbon material. The gas diffusion layer 400 is disposed parallel to the membrane electrode assembly 300.
[0025] The separator 200 prevents the leakage of reactant gases from the fuel cell unit 10. The separator 200 is made of, for example, a metallic material such as aluminum or titanium. Figure 2As shown, the separator 200 has a rectangular plate-like shape. Six manifold holes 221a, 221b, 222a, 222b, 223a, and 223b are formed on the separator 200. Manifold hole 221a is part of the oxidizer gas manifold 11a, manifold hole 221b is part of the oxidizer gas manifold 11b, manifold hole 222a is part of the refrigerant manifold 12a, manifold hole 222b is part of the refrigerant manifold 12b, manifold hole 223a is part of the fuel gas manifold 13a, and manifold hole 223b is part of the fuel gas manifold 13b.
[0026] like Figure 3 As shown, the separator 200 has a plurality of flow paths 210 and ribs 220 disposed such that they are sandwiched between the flow paths 210 on the surface facing the gas diffusion layer 400. The reactant gas flows through each flow path 210. More specifically, as... Figure 2 As shown, the reactant gas is supplied to each flow path 210 through manifold orifices 221a and 223a, and is discharged from each flow path 210 through manifold orifices 221b and 223b. At least a portion of the reactant gas flowing in each flow path 210 is supplied to the gas diffusion layer 400.
[0027] like Figure 3 As shown, each flow path 210 has a bottom surface 211 and a pair of side portions 212. The bottom surface 211 is isolated from the gas diffusion layer 400. Furthermore, the bottom surface 211 is arranged parallel to the gas diffusion layer 400. The pair of side portions 212 connect the bottom surface 211 and the rib 220 described later. The pair of side portions 212 are respectively connected to both ends of the bottom surface 211 in the width direction (X direction). The pair of side portions 212 are inclined such that the width of the flow path 210 widens from the bottom surface 211 side towards the gas diffusion layer 400 side. Therefore, the flow path 210 has a U-shaped shape in a cross-section parallel to the width direction. The detailed structure of the side portions 212 will be described later.
[0028] Ribs 220 are provided between each flow path portion 210. Alternatively, ribs 220 can be described as adjacent to flow path portions 210. Ribs 220 have flat surfaces. Ribs 220 are provided parallel to and in contact with the gas diffusion layer 400. Therefore, the load applied in the thickness direction of the separator 200 is applied to the gas diffusion layer 400 through the ribs 220. The two ends of the ribs 220 in the width direction are respectively connected to the side portions 212 of each of the two flow path portions 210 provided in a manner that sandwiches the ribs 220.
[0029] By repeatedly configuring the flow path section 210 and the rib section 220 as described above, in conjunction with... Figure 3 In the cross section shown, which is orthogonal to the direction of the reaction gas flow, the separator 200 has a concave-convex shape.
[0030] <Detailed structure of side section 212 and groove GR>
[0031] like Figure 2 As shown on the lower side, a plurality of grooves GR are provided on the side portion 212 of this disclosure. Specifically, each groove GR is provided from the connection portion between the side portion 212 and the rib portion 220 toward the bottom surface 211. The orientation of the groove GR is consistent with the direction of its long side. Each groove GR is arranged along the length direction (Y direction) of the flow path portion 210. In this embodiment, the width of the portion of the groove GR near the rib portion 220 is narrower than the width of the portion near the bottom surface 211. Alternatively, each groove GR has a convex planar projection shape in which the width widens from the rib portion side toward the bottom surface 211 side. The narrowest width of the groove GR is, for example, 1 mm to 2 mm. The widest width of the groove GR is, for example, 5 mm to 8 mm. The depth of the groove GR is, for example, 1 mm to 5 mm. The length of the groove GR is, for example, 3 mm to 10 mm.
[0032] Each GR tank is used for draining water from the gas diffusion layer 400 to the flow path 210. In the fuel cell unit 10, water is generated on the cathode side through the reaction of oxidant gas. Additionally, the water generated on the cathode side sometimes moves towards the anode side beyond the membrane electrode assembly 300. If the generated water stagnates, it will hinder the flow of reactant gas, reducing power generation efficiency. Therefore, it is preferable that the generated water is discharged to the outside of the fuel cell unit 10 via the flow path 210. However, in... Figure 3 In the contact portion AR1 between the rib 220 and the gas diffusion layer 400 shown, water may sometimes accumulate. This water stagnating in the contact portion AR1 hinders the movement of the reactant gas between the flow paths 210 and within the gas diffusion layer 400. Consequently, the spread of reactant gas throughout the entire membrane electrode assembly 300 is suppressed. Here, as disclosed herein, by providing a groove GR extending from the connection portion between the side portion 212 and the rib 220, the water stagnating between the rib 220 and the gas diffusion layer 400 can be discharged to the flow path 210. The water discharged to the flow path 210 is guided to the outside of the fuel cell unit 10 by the flow of the reactant gas.
[0033] According to the first embodiment of the fuel cell unit 10 described above, a plurality of grooves GR are provided on the side 212, extending from the connection portion between the side 212 and the rib 220 toward the bottom surface 211. Therefore, generated water that may be retained at the contact portion between the rib 220 and the gas diffusion layer 400 can be discharged through each groove GR. As a result, drainage performance can be improved.
[0034] Furthermore, in the fuel cell unit 10 according to the first embodiment, the width of the portion near the rib 220 in the tank GR is narrower than the width of the portion near the bottom surface 211. Therefore, capillary force can be used to guide the generated water accumulated between the rib 220 and the gas diffusion layer 400 to each tank GR. Thus, even when the flow rate of the reactant gas supplied to the fuel cell unit 10 is low, capillary force can be used to improve drainage performance.
[0035] B. Second implementation method:
[0036] Figure 4 This is a perspective view of the separator 200b for the fuel cell unit 10 in the second embodiment. Figure 4 It shows the relationship with Figure 2 The enlarged view of the lower side shows a portion of the separator 200b at the corresponding position. The shape of the groove GRb of the separator 200b in the second embodiment is different from that of the groove GR of the separator 200 in the first embodiment. The other structures of the fuel cell unit 10 in the second embodiment are the same as those in the fuel cell unit 10 in the first embodiment, and therefore their description is omitted.
[0037] like Figure 4 As shown, in the groove GRb, the width of the portion near the rib 220 is wider than the width of the portion near the bottom surface 211. The groove GRb can also be described as having a convex planar projection shape where the width narrows from the rib 220 side towards the bottom surface 211 side. The narrowest width of the groove GRb is, for example, 1 mm to 2 mm. The widest width of the groove GRb is, for example, 5 mm to 8 mm.
[0038] According to the fuel cell unit 10 of the second embodiment described above, the width of the portion near the rib 220 in the tank GRb is wider than the width of the portion near the bottom surface 211. Therefore, the generated water accumulated between the rib 220 and the gas diffusion layer 400 can be guided to the wider portion of the tank GRb. As a result, even when the separator 200 is made of a material with low hydrophilicity and the resulting capillary force is small, drainage performance can be improved.
[0039] C. Third implementation method:
[0040] Figure 5 This is a perspective view of the separator 200c used in the fuel cell unit 10 of the third embodiment. Figure 5 It shows the relationship with Figure 2 The enlarged view on the lower side shows a portion of the separator 200c at the corresponding position. The shape of the groove GRc in the separator 200c of the third embodiment is different from that of the groove GR in the separator 200 of the first embodiment. The other structures of the fuel cell unit 10 of the third embodiment are the same as those of the fuel cell unit 10 of the first embodiment, and therefore their description is omitted.
[0041] like Figure 5 As shown, the width of the groove GRc is constant from the rib 220 side to the bottom surface 211 side. In other words, the groove GRc has a constant width along its length. It can also be said that the groove GRc has a straight planar projection shape. The width of the groove GRc is, for example, 1mm to 5mm.
[0042] According to the fuel cell unit 10 of the third embodiment described above, the width of the groove GRc is constant from the rib 220 side to the bottom surface 211 side. Therefore, compared with the structure in which the width of the groove varies depending on the location, the groove GRc can be easily set.
[0043] D. Fourth implementation method:
[0044] Figure 6 This is a perspective view of the separator 200d for the fuel cell unit 10 in the fourth embodiment. Figure 6 It is shown that... Figure 2 The enlarged view of the lower side shows a portion of the separator 200d at the corresponding position. The shape of the groove GRd in the separator 200d of the fourth embodiment differs from the groove GRc in the separator 200c of the third embodiment. The other structures of the fuel cell unit 10 of the fourth embodiment are the same as those of the fuel cell unit of the third embodiment, and therefore their description is omitted.
[0045] like Figure 6 As shown, the groove GRd slopes from the rib 220 side toward the bottom surface 211 side in the direction of the reactant gas flow. The direction of the groove GRd's slope can also be described as incorporating the direction of the reactant gas flow. In this embodiment, the reactant gas flows in the -Y direction.
[0046] Furthermore, the construction of the groove GRd in the fourth embodiment can also be used in combination with the groove GR of the first embodiment or the groove GRb of the second embodiment. That is, the groove, which has any shape, can be inclined from the rib 220 side toward the bottom surface 211 side in the direction of reaction gas flow.
[0047] According to the fourth embodiment of the fuel cell unit 10 described above, the tank GRd is inclined from the rib 220 side to the bottom surface 211 side in the direction of reaction gas flow, so the generated water in the tank GRd can be easily discharged to the outside of the fuel cell unit 10 by the flow of reaction gas. As a result, the drainage performance of the fuel cell unit can be improved.
[0048] E. Other implementation methods:
[0049] (E1) In the first embodiment described above, the groove GR has a convex planar projection shape in which the width widens from the rib 220 side toward the bottom surface 211 side, but this disclosure is not limited to this. The groove GR can also be any shape in which the width widens from the rib 220 side toward the bottom surface 211 side. Furthermore, in the second embodiment described above, the groove GRb has a convex planar projection shape in which the width narrows from the rib 220 side toward the bottom surface 211 side, but this disclosure is not limited to this. The groove GRb can also be any shape in which the width narrows from the rib 220 side toward the bottom surface 211 side.
[0050] (E2) In the above embodiments, multiple slots GR, GRb, GRc, and GRd are provided, but this disclosure is not limited to this. Only one slot GR, GRb, GRc, and GRd may also be provided.
[0051] (E3) In the above embodiments, separators 200, 200b, 200c, and 200d are used in the fuel cell unit 10, but this disclosure is not limited thereto. Separators 200, 200b, 200c, and 200d can also be used in a water electrolysis unit.
[0052] (E4) In the above embodiments, the grooves GR, GRb, GRc, and GRd may also be provided only on any one of the pair of separators 200, 200b, 200c, and 200d.
[0053] (E5) In the above embodiments, the flow path 210 may also be formed as a so-called meandering flow path, which extends meanderingly in the region between the manifold holes 221a, 223a on the reaction gas supply side and the manifold holes 221b, 223b on the reaction gas discharge side.
[0054] (E6) In the above embodiments, the rib 220 has a flat surface, but this disclosure is not limited thereto. The rib 220 may have a curved surface.
[0055] This disclosure is not limited to the embodiments described above, and can be implemented in various structures without departing from its spirit. For example, in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects, the technical features in the embodiments can be appropriately replaced or combined. In addition, if a technical feature is not described as an essential technical feature in this specification, it can be appropriately deleted. For example, the present invention can also be implemented by the following description.
[0056] (1) According to one aspect of the present invention, a fuel cell unit is provided, comprising: a membrane electrode assembly; a pair of gas diffusion layers disposed such that they sandwich the membrane electrode assembly; and a pair of spacers disposed such that they sandwich the pair of gas diffusion layers. At least one of the pair of spacers has, on a surface facing the gas diffusion layers: a flow path for the flow of reactant gases; and a rib disposed adjacent to the flow path and in contact with the gas diffusion layers, the flow path having a bottom surface separated from the gas diffusion layers and a side portion connecting the bottom surface and the rib, and a groove provided on the side portion extending from the connection portion between the side portion and the rib toward the bottom surface.
[0057] According to this method, the fuel cell unit has grooves on its side extending from the connection portion with the rib towards the bottom surface, allowing generated water to be discharged from the gas diffusion layer through these grooves. This improves drainage performance.
[0058] (2) In the fuel cell unit of the above manner, the width of the portion near the rib in the groove may be narrower than the width of the portion near the bottom surface.
[0059] In this fuel cell unit, the width of the portion near the ribs in the tank is narrower than the width of the portion near the bottom, thus allowing capillary forces to guide generated water accumulated between the ribs and the gas diffusion layer into the tank. Therefore, even when the flow rate of the reactant gas supplied to the fuel cell unit is low, capillary forces can be used to improve drainage performance.
[0060] (3) In the fuel cell unit of the above manner, the width of the portion near the bottom surface in the groove may be narrower than the width of the portion near the rib.
[0061] In this fuel cell unit, the width of the portion near the ribs in the tank is wider than the width of the portion near the bottom, thus allowing generated water accumulated between the ribs and the gas diffusion layer to be guided to the wider portion of the tank. Therefore, drainage performance can be improved even when the separator is made of a material with low hydrophilicity and the resulting capillary force is small.
[0062] (4) In the fuel cell unit described above, the width of the slot can also be constant.
[0063] According to this method, the width of the slot in the fuel cell unit is constant, making it easier to set the slot compared to structures where the width of the slot varies depending on the location.
[0064] (5) In the fuel cell unit of the above-described manner, the groove may also be inclined from the rib side to the bottom side in the direction of the reaction gas flow.
[0065] In this fuel cell unit, since the tank is inclined from the rib side to the bottom side in the direction of reactant gas flow, the generated water in the tank can be easily discharged to the outside of the fuel cell unit by the flow of reactant gas. This improves the drainage performance of the fuel cell.
Claims
1. A fuel cell unit comprising: a membrane electrode assembly; a pair of gas diffusion layers disposed such that they sandwich the membrane electrode assembly; and a pair of spacers disposed such that they sandwich the pair of gas diffusion layers, wherein, At least one of the pair of separators has, on the surface facing the gas diffusion layer, a flow path for the flow of reactant gas, and a rib disposed adjacent to the flow path and in contact with the gas diffusion layer. The flow path section has a bottom surface that is separate from the gas diffusion layer and a side portion that connects the bottom surface to the rib. A groove is provided on the side portion, extending from the connection portion between the side portion and the rib portion toward the bottom surface.
2. The fuel cell unit according to claim 1, wherein, In the groove, the width of the portion near the rib is narrower than the width of the portion near the bottom surface.
3. The fuel cell unit according to claim 1, wherein, In the groove, the portion near the rib is wider than the portion near the bottom surface.
4. The fuel cell unit according to claim 1, wherein, The width of the groove is constant.
5. The fuel cell unit according to any one of claims 1 to 4, wherein, The trough is inclined along the direction of the flow of the reaction gas.