Fuel cell structure

Abstract

To provide a fuel cell structure that can suppress the backflow of accumulated water with a simple configuration.SOLUTION: A separator 3 is formed with a tunnel portion 10 that bypasses a seal portion 8 and connects a communication hole 4 to a fluid passage 7. A tunnel portion 10 includes a plurality of tunnel bodies 11 extending from communication hole 4 toward the fluid passage 7, and a connecting passage 13 that connects tip ends 12 of the plurality of tunnel bodies 11 to each other such that fluid can flow through. The tunnel portion 10 also has a plurality of openings 14 that connect the connecting passage 13 to the fluid passage 7. Of the plurality of tunnel bodies 11, end tunnel bodies 15 connected to the end portions 13a of the connecting passages 13 are connected at an acute angle to the connecting passage 13. A connection portion 16 between the connecting passage 13 and the end tunnel bodies 15 is curved in an arc.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to fuel cell structures. [Background technology]

[0002] A conventional fuel cell structure has an anode discharge communication hole that communicates with one horizontal end of the fuel fluid flow channel and discharges the fuel fluid in the stacking direction of the membrane electrode assembly and separator. The fuel cell structure also has a cathode discharge communication hole that communicates with the other horizontal end of the oxidant fluid flow channel and discharges the oxidant fluid in the stacking direction. In this fuel cell structure, the bottom of the lowest cathode discharge communication hole is located lower than the bottom of the lowest anode discharge communication hole (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-71445 Summary of the Invention [Problem to be solved by the invention]

[0004] The separator has a tunnel that bypasses the seal that seals the fluid flow path and the communication hole, connecting the two. In conventional fuel cell structures, restrictions on the relative positions of the anode discharge communication hole and the cathode discharge communication hole inevitably restrict the location of the tunnel, which creates a problem. Furthermore, the location of the tunnel affects the fluid flow within the tunnel, making it difficult to prevent backflow of generated water that accumulates. Thus, prioritizing the relative positions of the anode discharge communication hole and the cathode discharge communication hole could result in failure to prevent backflow of accumulated water, and further improvements are needed. The present invention aims to provide a fuel cell structure that can suppress the backflow of accumulated water with a simple configuration. [Means for solving the problem]

[0005] To solve the above problems, the fuel cell structure of the present invention alternately stacks membrane electrode assemblies, membrane electrode assemblies each having a frame member surrounding the membrane electrode assemblies, and separators that separate the membrane electrode assemblies. The frame member and the separators have through-holes that penetrate in the stacking direction and communicate with each other, allowing the power-generating fluid to flow. Fluid passages that supply the power-generating fluid to the membrane electrode assemblies are provided between the membrane electrode assemblies and the separators. A seal is provided around the through-hole to seal between the through-hole and the fluid passage.

[0006] The separator has a tunnel portion that bypasses the seal portion and connects the communication hole to the fluid passage. The tunnel portion has a plurality of tunnel bodies extending from the communication hole toward the fluid passage, a connecting passage that connects the tip ends of the plurality of tunnel bodies to allow fluid to flow, and a plurality of openings that connect the connecting passage to the fluid passage. Of the plurality of tunnel bodies, an end tunnel body that connects to an end of the connecting passage is connected at an acute angle to the connecting passage, and the connection portion between the connecting passage and the end tunnel body is curved in an arc. [Effects of the Invention]

[0007] According to the present invention, a fuel cell structure that can suppress backflow of accumulated water with a simple configuration is provided. [Brief explanation of the drawings]

[0008] [Figure 1] 3 is a plan view of a separator showing a portion where a fluid passage communicates with a communication hole through a tunnel portion in the fuel cell structure according to the embodiment; FIG. [Figure 2] FIG. 2 is a plan view illustrating the configuration of a main part of the fuel cell structure according to the embodiment. [Figure 3] 3 is a cross-sectional view taken along line III-III in FIG. 2, illustrating the configuration of a main part of the fuel cell structure according to the embodiment. [Figure 4] 1 is a plan view of a separator illustrating the overall configuration of a fuel cell structure according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a fuel cell structure according to an embodiment of the present invention will be described with reference to the accompanying drawings. The same components are designated by the same reference numerals, and redundant description will be omitted. In the fuel cell structure of the embodiment, a stacked cell stack formed by stacking a plurality of unit cells 1, each having a separator 3 and a membrane electrode assembly 2 (see FIG. 3), in a stacking direction W is housed inside a battery casing. Each unit cell 1 is formed by alternately stacking the membrane electrode assembly 2 and separators 3 disposed on both sides of the membrane electrode assembly 2 to separate the membrane electrode assemblies 2 from each other.

[0010] Of these, the membrane electrode structure 2 has a membrane electrode assembly 5 that forms an active region and a frame member 6 that surrounds the membrane electrode assembly 5. The frame member 6 and the separator 3 are formed with communication holes 4 that penetrate in the stacking direction W and communicate with each other, through which a power generation material fluid (hereinafter also referred to as fluid) H flows. As shown in Fig. 4, the stacked cell stack is provided with a fluid supply manifold 9 that distributes and supplies a power generation material fluid H to the fluid passages 7. The stacked cell stack is also provided with a fluid discharge manifold 19 that collects and discharges the fluid H flowing down from the fluid passages 7. The fluid supply manifold 9 and the fluid discharge manifold 19 are configured by communicating the communication holes 4 formed in the frame member 6 and the separator 3 in the stacking direction W. In the embodiment, the configuration of the fluid discharge manifold 19 will be mainly described, and a description of the fluid supply manifold 9 that is configured in a similar manner will be omitted.

[0011] Between the membrane electrode assembly 2 and the separator 3, there is provided a fluid passage 7 for supplying a fluid serving as a power generation material to the membrane electrode assembly 5. Different types of fluids, such as power generation material fluids H, such as hydrogen and oxygen, are supplied to the fluid passages 7 on both sides of the membrane electrode assembly 2 between the active regions of the membrane electrode assembly 5 to generate power. A seal portion 8 is provided around the communication hole 4 formed in the fluid discharge manifold 19 to seal between the communication hole 4 and the fluid passage 7. As shown in FIG. 3 , the seal portion 8 is configured by pressing a protrusion 8a formed on the separator 3 against the frame member 6 of the membrane electrode assembly 2.

[0012] Separator 3 also has a tunnel portion 10 that bypasses seal portion 8 and connects communication hole 4 to fluid passage 7. In this embodiment, tunnel portion 10 is formed as a groove recessed in the surface of separator 3 opposite membrane electrode assembly 2. Tunnel portion 10 has a plurality of tunnel bodies 11 that extend from communication hole 4 toward fluid passage 7, as shown in FIG. Each tunnel body 11 is provided in a direction perpendicular to the protrusions 8a formed on the separator 3, and is configured to bypass the seal portion 8 by intersecting with the seal portion 8 in the stacking direction W. Note that while Fig. 3 shows an end tunnel body 15, which will be described later, each of the other tunnel bodies 11 constituting the tunnel portion 10 is similarly configured to bypass the seal portion 8 by intersecting with the stacking direction W.

[0013] The tunnel portion 10 also has a connecting passage 13 that connects the tip ends 12 of the multiple tunnel bodies 11 to each other in a flow-through manner. In this embodiment, the connecting passage 13 is formed by a groove recessed in the surface of the separator 3 opposite to the membrane electrode assembly 2. The connecting passage 13 of the embodiment is provided at a position spaced apart by a predetermined distance along the periphery of the communication hole 4 and extends over the entire length of the range E where the communication hole 4 and the fluid passage 7 are adjacent to each other. The tunnel portion 10 has a plurality of openings 14 that connect the connecting passage 13 to the fluid passage 7. In this embodiment, the openings 14 are formed by being drilled in the side surface of the connecting passage 13 on the membrane electrode assembly 5 side.

[0014] 2, in the fuel cell structure of the embodiment, an end tunnel body 15 is provided at the end of the connecting path 13 among the multiple tunnel bodies 11. The end tunnel body 15 is connected to the end 13a of the connecting path 13 by a connection part 16. The end tunnel body 15 is connected to the connecting passage 13 at an acute angle α. A connecting portion 16 between the connecting passage 13 and the end tunnel body 15 is curved in an arc shape.

[0015] In this embodiment, as shown in FIG. 1, the connection portion 16 of the end tunnel body 15 is provided at a position spaced a predetermined distance D from the opening 14 of the end portion 13a. That is, in the connection portion 16 of the embodiment, the opening 14 closest to the connection portion 16 among the plurality of openings 14 is provided at a position spaced apart from the connection portion 16. In other words, the openings 14 are not provided in the curved connection portion 16. For example, in the embodiment, the dimension D to the connection portion 16 is set to be larger than the dimension D1 from the opening 14 to the tip 12 of the nearest tunnel main body 11 (D>D1).

[0016] In the fuel cell structure of this embodiment configured as above, the fluid supply manifold 9 shown in Fig. 4 connects the fluid passages 7 sides of the multiple tunnel bodies 11 to the connecting passage 13. Therefore, the power generation material fluid H supplied into the fuel cell is first dispersed from the connecting passage 13 through each opening 14 and supplied to the fluid passages 7.

[0017] In the fluid supply manifold 9, a plurality of openings 14 are formed in the connecting passage 13. Therefore, compared to when there is a single opening 14 or when there is one opening 14 for one tunnel body 11, pressure loss can be reduced and power generation efficiency can be improved. In addition, in this embodiment, the connecting path 13 extends over the entire length of the range E where the communication hole 4 and the fluid passage 7 are adjacent to each other. Therefore, many openings 14 can be provided in the connecting path 13 over the relatively long range E that extends over three sides on the fluid passage 7 side, further reducing pressure loss and improving power generation efficiency. Furthermore, in this embodiment, the openings 14 are offset so as not to face the tip ends 12 of the tunnel main body 11. For example, as shown in Fig. 1, if the number of openings 14 is increased by one more than the number of tips, the total opening area of ​​the openings 14 increases. Therefore, the power generation material fluid H supplied from each tip end 12 can be diffused, further reducing pressure loss.

[0018] The opening diameter, opening position, and number of openings 14 can be set arbitrarily. This allows for compatibility with the size and shape of the fluid passage 7 or the active region, improving power generation efficiency. When power generation material fluid H, such as hydrogen and oxygen, passes through the fluid passages 7 on both sides of the membrane electrode assembly 2, power generation occurs through a reaction in the membrane electrode assembly 5. As the membrane electrode assembly 5 generates power, water is produced and flows down the fluid passages 7.

[0019] Meanwhile, the fluid discharge manifold 19 formed on the separator 3 has the function of collecting and discharging the generated water generated in the active region of the fuel cell through the tunnel portion 10. However, the generated water that cannot be completely discharged may accumulate in the tunnel body 11. Once the generated water is drained into the communication hole 4, it may accumulate in the area where the separators 3 are stacked and become stagnant water that remains in contact with the metallic separators 3 for a long time. In this state, if a traveling vehicle stops or stops in an inclined position, the stagnant water on the separator 3 side will come into contact with the produced water on the active area side, especially in the lowest end tunnel body 15 connected by the end 13a of the connecting path 13, and the liquids will become connected. If liquid leakage occurs, metal components such as iron eluted from the separator 3 may infiltrate the active region together with the accumulated water, possibly causing deterioration of the membrane electrode assembly 5 of the membrane electrode structure 2.

[0020] For this reason, in the fuel cell structure of the present embodiment, as shown in Fig. 2, the end 13a of the connecting passage 13 of the multiple tunnel bodies 11 is connected to the end tunnel body 15 by the connecting portion 16 that is curved in an arc. Therefore, the produced water that flows down from the fluid passage 7 through the multiple openings 14 into the end tunnel body 15 flows smoothly along the arc-shaped connecting portion 16 without stagnating in the connecting passage 13. Therefore, the produced water is drained in the direction of the communication hole 4 with little resistance.

[0021] Furthermore, the end tunnel main body 15 is connected at an acute angle α to the connecting passage 13 by a connecting portion 16 that is efficiently arranged in the space between the outer peripheral corner of the communicating hole 4 and the fluid passage 7. The opening 14 in this embodiment is provided at a position that is a predetermined distance D away from the connecting portion 16 of the end tunnel main body 15. As a result, the opening 14 is not formed near the connecting portion 16 of the end tunnel main body 15. Furthermore, the opening 14 is arranged above the connecting portion 16, and the path distance to the nearest opening 14 is longer than the path distance when the end tunnel main body 15 is directly connected to the connecting passage 13 in a straight line without providing the connecting portion 16. For this reason, even if the produced water cannot be completely discharged from the end tunnel main body 15, it is unlikely to flow back toward the upper opening 14 closest to the connection part 16. In addition, the closest opening 14 is located above the connection part 16. Therefore, the produced water in the end tunnel main body 15 is discharged toward the communicating hole 4 together with the produced water that flows down sequentially from the opening 14. In addition, the position of the closest opening 14, which is placed above the connection part 16, is higher than the intersection position with the seal part 8 of the end tunnel main body 15 that is connected to the connection part 16. For this reason, the produced water in the connection part 16 is easily discharged toward the communicating hole 4.

[0022] In this way, the produced water that flows down into each tunnel body 11 and end tunnel body 15 of tunnel section 10 is discharged without accumulating in connecting channel 13. This reduces the risk of the accumulating water on the separator 3 side becoming liquid-connected with the produced water on the active region side. Therefore, the fuel cell structure of the embodiment exhibits a practically beneficial effect of preventing deterioration of membrane electrode assemblies 5 provided in membrane electrode structure 2.

[0023] As described above, in this invention, membrane electrode assemblies 2 each having a membrane electrode assembly 5 and a frame member 6 surrounding the membrane electrode assemblies 5, and separators 3 separating the membrane electrode assemblies 2 are alternately stacked. The frame member 6 and the separators 3 are formed with communication holes 4 that penetrate in the stacking direction W and communicate with each other, allowing the power generation material fluid H to flow. Fluid channels 7 that supply the power generation material fluid H to the membrane electrode assemblies 5 are provided between the membrane electrode assemblies 2 and the separators 3. A seal portion 8 that seals between the communication holes 4 and the fluid channels 7 is provided around the communication holes 4.

[0024] Separator 3 is formed with a tunnel portion 10 that bypasses seal portion 8 and connects communication hole 4 to fluid passage 7. Tunnel portion 10 has a plurality of tunnel bodies 11 extending from communication hole 4 toward fluid passage 7, and a connecting passage 13 that connects tip ends 12 of the plurality of tunnel bodies 11 to each other so that fluid can flow through. Tunnel portion 10 also has a plurality of openings 14 that connect connecting passage 13 to fluid passage 7. Of the plurality of tunnel bodies 11, end tunnel bodies 15 that connect to end portions 13a of connecting passages 13 are connected at an acute angle to connecting passage 13. Connection portion 16 between connecting passage 13 and end tunnel bodies 15 is curved in an arc.

[0025] As a result, the fuel cell structure of the present invention can suppress backflow of accumulated water with a simple configuration. That is, the end tunnel body 15 can smoothly drain the generated water flowing down through the connection portion 16 and prevent backflow.

[0026] The connecting passage 13 extends over a range E where the communication hole 4 and the fluid passage 7 are adjacent to each other. This allows many openings 14 to be provided in the connecting passage 13, further reducing pressure loss and improving power generation efficiency.

[0027] The opening 14 is provided at a position spaced apart from the connection portion 16 of the end tunnel body 15 . This allows the path distance to the nearest opening 14 to be longer than when the end tunnel body 15 is connected to the connecting path 13 at right angles like the other tunnel bodies 11. Therefore, the produced water is less likely to flow back toward the opening 14. This reduces the risk of the accumulated water on the separator 3 side joining with the produced water on the active region side, thereby providing a practically beneficial effect of preventing deterioration of the membrane electrode assembly 5 of the membrane electrode structure 2.

[0028] The present invention is not limited to the above-described embodiments, and various modifications are possible. The above-described embodiments are provided as examples to facilitate understanding of the present invention, and are not necessarily limited to those including all of the configurations described. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to delete part of the configuration of each embodiment, or to add or replace other configurations. Possible modifications of the above-described embodiments include, for example, the following.

[0029] In the embodiment, the present invention has been described as being applied to both the fluid supply manifold 9 and the fluid discharge manifold 19 among the multiple manifolds formed on the separator 3, but this is not particularly limited. For example, the present invention may be applied to only the fluid supply manifold 9 or only the fluid discharge manifold 19. In other words, the present invention may be applied to any manifold as long as the end tunnel body 15 is connected to the connecting passage 13 at an acute angle by the connection portion 16, and the connection portion 16 is curved in an arc, and the shape, number, and material of the manifold are not limited.

[0030] In addition, in the embodiment, the seal portion 8 is configured to have the protrusions 8a formed on the separator 3, but is not particularly limited to this. For example, the seal portion 8 may be configured by providing an elastic seal material sandwiched between the separators 3, 3 or between the separator 3 and the membrane electrode assembly 2. [Explanation of symbols]

[0031] 2 Membrane electrode structure 3 Separator 4 Communication hole 5 Membrane electrode assembly 6 Frame members 7 Fluid passage 8 Seal part 10 Tunnel section 11 Tunnel body 12 Tip 13 Connecting road 13a End 14 Openings 15 End tunnel body 16 Connection

Claims

1. A fuel cell structure in which a membrane electrode assembly having a frame member surrounding the membrane electrode assembly and a separator separating the membrane electrode assemblies are alternately stacked, the frame member and the separators are formed with communication holes that penetrate in the stacking direction and communicate with each other, through which a power-generating material fluid flows; a fluid passage that supplies the power-generating material fluid to the membrane electrode assembly is provided between the membrane electrode assembly and the separators; a seal portion that seals between the communication hole and the fluid passage is provided around the communication hole; and a tunnel portion is formed in the separators that bypasses the seal portion and communicates between the communication hole and the fluid passage, the tunnel portion having a plurality of tunnel bodies extending from the communication hole toward the fluid passage, a connecting path that connects tip ends of the plurality of tunnel bodies to allow fluid to flow therethrough, and a plurality of openings that communicate the connecting path with the fluid passage, Among the multiple tunnel bodies, an end tunnel body connected to an end of the connecting path is connected at an acute angle to the connecting path, and the connection portion between the connecting path and the end tunnel body is curved in an arc. Fuel cell structure.

2. The connecting passage extends over a range in which the communication hole and the fluid passage are adjacent to each other. The fuel cell structure of claim 1 .

3. The opening is provided at a position spaced apart from the connection portion of the end tunnel body. The fuel cell structure of claim 1 .

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