JP2023157474A - Fuel cell - Google Patents

Abstract

To provide a fuel cell capable of suppressing the occurrence of a blockage in a comb channel.SOLUTION: A disclosed fuel cell includes: a membrane electrode assembly that generates electricity using reactive gas; a frame that holds the membrane electrode assembly; and a pair of separators joined with plates facing each other and overlapping the frame. The pair of separators and the frame have a manifold hole that penetrates in the thickness direction and allows the reactive gas to flow therethrough. One of the pair of separators encloses the manifold hole, and has a convex part that supports the frame. Between the pair of separators, the annular channel through which the reaction gas flows along the convex part, an outlet flange located at the manifold hole side than the annular flow path, and a comb channel that connects the annular channel and the outlet flange are provided. Between the pair of separators, a flow path X is provided for connecting the annular flow path and the outlet flange and guiding the stagnant water accumulated at the outlet flange to the annular flow path.SELECTED DRAWING: Figure 8

Description

TECHNICAL FIELD This disclosure relates to fuel cells.

A seal line is provided in a pair of separators of a fuel cell around the manifold holes so that the reaction gas used for power generation does not leak from the manifold holes to the outside of the separators. The manifold hole is sealed by a protrusion formed along the seal line.

A groove-shaped channel (hereinafter referred to as a "seal channel") through which the reaction gas flows is provided on the back side of the convex portion. A plurality of connecting channels are connected to the seal channel such that reactant gas flows between the power generation region and the manifold hole through the seal channel.

Since the reaction gas contains moisture generated, for example, in power generation, water droplets due to condensation of moisture also flow into the seal channel. For example, Patent Document 1 discloses a fuel cell system including a fuel cell, a circulation flow path, and a hydrogen pump. Further, Patent Document 1 discloses that the hydrogen pump is rotated in the opposite direction to move water to the center of the cell.

Japanese Patent Application Publication No. 2018-181484

Between the pair of separators, there is an annular flow path through which the reaction gas flows along a convex portion, an outlet flange located closer to the manifold hole than the annular flow path, and a connection between the annular flow path and the outlet flange. In some cases, a comb-teeth channel is provided. If water remains in the outlet flange portion, for example, after scavenging is completed, the remaining water may be sucked back into the comb-tooth flow path, causing blockage in the comb-tooth flow path.

The present disclosure has been made in view of the above-mentioned circumstances, and a main purpose of the present disclosure is to provide a fuel cell in which clogging of the comb tooth flow path is suppressed.

The present disclosure includes a membrane electrode assembly that generates electricity using a reactive gas, a frame that holds the membrane electrode assembly, and a pair of separators that are joined with their plate surfaces facing each other and overlap the frame. , the pair of separators and the frame have a manifold hole that penetrates in the thickness direction and through which the reaction gas flows, and one of the pair of separators has a convex part that surrounds the manifold hole and supports the frame. Between the pair of separators, there is provided an annular flow path through which the reaction gas flows along the convex portion, an outlet flange portion disposed closer to the manifold hole than the annular flow path, and an annular flow path and an annular flow path. A comb-tooth channel is provided between the pair of separators to connect the outlet flange, and a comb-tooth channel is provided between the pair of separators to connect the annular channel and the outlet flange, and a comb-tooth channel is provided between the pair of separators to connect the annular channel and the outlet flange, and a comb-tooth channel is provided between the pair of separators to connect the annular channel and the outlet flange. A fuel cell is provided, in which a flow path X is provided that guides the fuel to the annular flow path.

According to the present disclosure, by providing the flow path X (a flow path for sucking back the accumulated water accumulated in the outlet flange portion), a fuel cell is obtained in which blockage of the comb-tooth flow path is suppressed.

The present invention has the advantage that it is possible to provide a fuel cell in which blockage of the comb tooth flow path is suppressed.

FIG. 1 is an exploded perspective view showing an example of a single cell of a fuel cell. FIG. 2 is a plan view showing an example of an anode separator. FIG. 3 is a plan view showing an example of a cathode separator. 3 is a plan view showing the vicinity of a through hole of an anode separator of Comparative Example 1. FIG. 5 is a sectional view taken along line AA, line BB, or line CC in FIG. 4. FIG. 3 is a plan view showing the vicinity of a manifold hole in Comparative Example 2. FIG. 7 is a sectional view taken along line DD in FIG. 6. FIG. FIG. 3 is a plan view showing the vicinity of the manifold hole of the embodiment.

FIG. 1 is an exploded perspective view showing an example of a single cell 2 of a fuel cell. Fuel cells are used, for example, in fuel cell vehicles, but their uses are not limited. The fuel cell is of a polymer electrolyte type and is configured to include a laminate in which a plurality of single cells 2 are stacked.

The unit cell 2 is supplied with a fuel gas (for example, hydrogen) and an oxidizing gas (for example, air), and generates electricity through an electrochemical reaction between the fuel gas and the oxidizing gas. Note that the fuel gas and the oxidizing gas are examples of reactive gases.

The unit cell 2 includes a MEGA 20, a frame 21, a cathode separator 23, and an anode separator 24 arranged along the stacking direction of the unit cell 2. Note that the cathode separator 23 and the anode separator 24 are an example of a pair of separators.

The MEGA 20 includes a membrane electrode assembly (MEA) 200 and a pair of gas diffusion layers (GDL) 201 and 202 that sandwich the MEA 200. The symbol P indicates the laminated structure of the MEA 200. The MEA 200 includes an electrolyte membrane 200a, and an anode electrode catalyst layer 200b and a cathode electrode catalyst layer 200c that sandwich the electrolyte membrane 200a.

The electrolyte membrane 200a includes, for example, an ion exchange resin membrane that exhibits good proton conductivity in a wet state. Examples of such ion exchange resin membranes include fluororesin membranes having sulfonic acid groups as ion exchange groups, such as Nafion (registered trademark).

The anode electrode catalyst layer 200b and the cathode electrode catalyst layer 200c are each formed as a gas-diffusible porous layer containing catalyst-supporting conductive particles and a proton-conducting electrolyte. For example, the anode electrode catalyst layer 200b and the cathode electrode catalyst layer 200c are formed as a dry coating film of catalyst ink, which is a dispersed solution containing platinum-supported carbon and a proton-conducting electrolyte.

Fuel gas is supplied to the anode electrode catalyst layer 200b through one gas diffusion layer 201, and oxidizing gas is supplied to the cathode electrode catalyst layer 200c through the other gas diffusion layer 202. The gas diffusion layers 201 and 202 are formed, for example, by laminating a water-repellent microporous layer on a base material such as carbon paper. Note that the microporous layer is formed by containing, for example, a water-repellent resin such as PTFE (polytetrafluoroethylene) and a conductive material such as carbon black. The MEA 200 generates electricity through an electrochemical reaction using an oxidant gas and a fuel gas.

The frame 21 is made of a resin sheet having a rectangular outer shape, for example. Examples of the material for the frame 21 include polyethylene terephthalate (PET) resin, syndiotactic polystyrene (SPS) resin, and polypropylene (PP) resin. The frame 21 has a frame shape, and a rectangular opening 210 is provided in the center.

The opening 210 is provided at a position corresponding to the MEGA 20, and the outer peripheral end of the MEA 200 is bonded to the edge of the opening 210 via an adhesive layer. As a result, the MEA 200 is held in the frame 21.

Furthermore, through holes 211 to 216 are provided at the end of the frame 21, passing through in the thickness direction. The through holes 211 , 215 , and 214 are provided at one end of the frame 21 , and the through holes 213 , 216 , and 212 are provided at the other end of the frame 21 . The through holes 211 to 216 overlap the through holes 231 to 236 and 241 to 246 of the cathode separator 23 and the anode separator 24, respectively.

The through holes 211 , 241 , and 231 are part of an anode side inlet manifold that is a fuel gas supply port, and the fuel gas flows along the stacking direction of the unit cells 2 . The through holes 212 , 242 , and 232 are part of an anode-side outlet manifold that is a fuel gas outlet, and fuel off-gas flows along the stacking direction of the unit cells 2 .

The through holes 213 , 243 , and 233 are part of a cathode-side inlet manifold that is a supply port for the oxidizing gas, and the oxidizing gas flows along the stacking direction of the unit cells 2 . The through holes 214 , 244 , and 234 are part of a cathode-side outlet manifold that is an oxidizing gas outlet, and the oxidizing off-gas flows along the stacking direction of the unit cells 2 .

The through holes 215, 245, and 235 are part of a cooling water inlet manifold that is a supply port for cooling water that cools the unit cells 2, and the cooling water flows along the stacking direction of the unit cells 2. The through holes 216, 246, and 236 are part of a cooling water outlet manifold that is a cooling water outlet, and the cooling water flows along the stacking direction of the unit cells 2.

The cathode separator 23 and the anode separator 24 are formed into plate shapes of metal such as SUS, titanium, or the like, and have a rectangular outer shape. The cathode separator 23 and the anode separator 24 are joined to each other by, for example, laser welding, with their plate surfaces facing each other. The anode separator 24 is arranged on the anode side of the MEGA 20, and the cathode separator 23 is arranged on the cathode side of the MEGA 20 of another single cell 2 adjacent to the single cell 2.

Further, the anode separator 24 is bonded to the frame 21 with an adhesive. Thereby, the frame 21 is fixed to the anode separator 24.

The anode separator 24 has through holes 241 to 246 penetrating in the thickness direction and an anode channel portion 240 in the shape of a corrugated plate. The through holes 241 , 245 , and 244 are provided at one end of the anode separator 24 , and the through holes 243 , 246 , and 242 are provided at the other end of the anode separator 24 . Note that the through holes 241 to 244 are examples of manifold holes through which the reaction gas flows.

A groove-shaped fuel gas flow path through which fuel gas flows is formed on the surface of the anode flow path section 240 on the MEGA 20 side. The fuel gas flow path faces the gas diffusion layer 201, and the fuel gas is supplied to the gas diffusion layer 201 from the fuel gas flow path. Furthermore, a groove-shaped cooling water flow path through which cooling water flows is formed on the surface of the anode flow path portion 240 on the cathode separator 23 side.

The anode channel portion 240 is formed by bending using a press die, for example. The fuel gas flow path and the cooling water flow path may be formed, for example, in a straight line or in a meandering manner.

Further, the cathode separator 23 has through holes 231 to 236 penetrating in the thickness direction and a corrugated plate-shaped cathode channel portion 230. The through holes 231 , 235 , and 234 are provided at one end of the cathode separator 23 , and the through holes 233 , 236 , and 232 are provided at the other end of the cathode separator 23 .

A groove-shaped cooling water flow path through which a cooling medium flows is formed on the surface of the cathode flow path portion 230 on the anode separator 24 side. Further, a groove-shaped oxidant gas flow path through which the oxidant gas flows is formed on the surface of the cathode flow path portion 230 on the MEGA 20 side of another adjacent single cell. The oxidant gas flow path faces the gas diffusion layer 202 of the MEGA 20 of another adjacent single cell 2, and the oxidant gas is supplied to the gas diffusion layer 202 from the oxidant gas flow path.

The cathode channel portion 230 is formed by bending using a press die, for example. The coolant flow path and the fuel gas flow path may be formed, for example, in a straight line or in a meandering manner. Note that the cathode separator 23 and the anode separator 24 are not limited to metal, and may be formed by carbon molding, for example.

(Configuration of anode separator 24 and cathode separator 23)
FIG. 2 is a plan view showing an example of the anode separator 24, and FIG. 3 is a plan view showing an example of the cathode separator 23. FIG. 2 shows the plate surface of the anode separator 24 on the MEGA 20 side, and FIG. 3 shows the plate surface of the cathode separator 23 on the adjacent single cell 2 side when viewed from the front from the anode separator 24 side. There is.

The fuel gas flows through the fuel gas flow path in the anode flow path section 240 from the through holes 241 and 231 and is discharged to the through holes 242 and 232. The MEGA 20 is stacked in the fuel gas flow path in the anode flow path section 240, and fuel gas is supplied to the MEGA 20 from the fuel gas flow path.

The oxidizing gas flows through the oxidizing gas flow path in the cathode flow path section 230 from the through holes 243 and 233, and is discharged to the through holes 244 and 234. MEGAs 20 of adjacent single cells 2 are stacked in the oxidant gas flow path in the cathode flow path section 230, and oxidant gas is supplied to the MEGA 20 from the oxidant gas flow path.

Further, the cooling water flows through the cooling water flow path in the anode flow path section 240 from the through holes 245 and 235 and is discharged to the through holes 246 and 236. The cooling water flow path is formed between the cathode flow path section 230 and the anode flow path section 240. The cooling water absorbs the heat generated by the power generation of the MEGA 20.

Symbols L0s to L6s indicate spring seal lines for sealing the inside of the fuel cell from the outside air. A convex portion protruding toward the frame 21 is provided on the plate surface of the cathode separator 23 along the spring seal lines L0s to L6s. When the frame 21 overlaps the anode separator 24, the convex portion contacts the frame 21 and supports the frame 21 with elastic force. At this time, since the convex portion presses the frame 21, the area inside the spring seal lines L0s to L6s is sealed.

On the other hand, on the plate surface of the anode separator 24, a convex portion protruding toward the frame 21 of the adjacent single cell 2 is provided along the spring seal lines L0s to L6s. When the frame 21 overlaps the anode separator 24, the convex portion contacts the frame 21 and supports the frame 21 with elastic force. At this time, since the convex portion presses the frame 21, the area inside the spring seal lines L0s to L6s is sealed.

Further, on the back side of the convex portions of the anode separator 24 and the cathode separator 23, concave portions, or grooves, which are integral with the convex portions are formed, and fuel gas, oxidant gas, or cooling water flows into each groove. A seal channel is formed.

The spring seal line L0s is set to surround the through holes 241 to 244, 231 to 234, the anode flow path section 240, and the cathode flow path section 230. The spring seal lines L1s to L6s are set to surround the through holes 241 to 246 and 231 to 236, respectively. The spring seal lines L0s to L6s prevent fuel gas, oxidizing gas, and cooling water from leaking to the outside from between the anode separator 24 and the frame 21.

Cooling water flows through the seal channels along the spring seal lines L0s, L5s, and L6s. The cooling water flows through the introduction channel R5 from the through holes 245 and 235, and flows into the cooling water channels of the anode channel section 240 and the cathode channel section 230. The introduction channel R5 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The introduction channel R5 is connected to the seal channels along the spring seal lines L0s and L5s. Cooling water flows between the introduction channel R5 and the seal channels along the spring seal lines L0s and L5s.

Further, the cooling water flows from the cooling water channels of the anode channel section 240 and the cathode channel section 230 through the lead-out channel R6 and is discharged from the through holes 246 and 236. The outlet flow path R6 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The outlet channel R6 is connected to seal channels along the spring seal lines L0s and L6s. The cooling water flows from the outlet channel R6 between the seal channels along the spring seal lines L0s and L6s.

Fuel gas flows through the seal channels along the spring seal lines L1s and L2s. The fuel gas flows through the introduction channel R1 from the through holes 241 and 231, passes through the opening H1 in the plate surface of the anode separator 24, and flows into the fuel gas channel in the anode channel section 240. The introduction channel R1 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The introduction channel R1 is connected to a seal channel along the spring seal line L1s. The fuel gas flows between the introduction channel R1 and the seal channel along the spring seal line L1s.

The fuel gas passes from the fuel gas flow path of the anode flow path section 240 through the opening H2 in the plate surface of the anode separator 24, and flows into the outlet flow path R20. Since the outlet channel R20 is connected to the seal channel along the spring seal line L2s, the fuel gas flows from the outlet channel R20 to the seal channel. The outlet flow path R20 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The seal flow path along the spring seal line L2s is connected to the through holes 242 and 232 via the discharge flow path R21. The fuel gas is discharged from the seal passage through the discharge passage R21 to the through holes 242 and 232. The discharge flow path R21 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

Oxidizing gas flows through the seal channels along the spring seal lines L3s and L4s. The oxidizing gas flows through the introduction channel R3 from the through holes 243 and 233, passes through the opening H3 in the plate surface of the cathode separator 23, and flows into the oxidizing gas channel in the cathode channel section 230. The introduction channel R3 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The introduction channel R3 is connected to a seal channel along the spring seal line L3s. The oxidizing gas flows between the introduction channel R3 and the seal channel along the spring seal line L3s.

The oxidizing gas passes from the oxidizing gas flow path of the cathode flow path section 230 through the opening H4 in the plate surface of the cathode separator 23, and flows into the outlet flow path R40. Since the outlet channel R40 is connected to the seal channel along the spring seal line L4s, the fuel gas flows from the outlet channel R40 to the seal channel. The outlet flow path R40 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

The seal flow path along the spring seal line L4s is connected to the through holes 244 and 234 via the discharge flow path R41. The oxidizing gas is discharged from the seal passage through the discharge passage R41 to the through holes 244 and 234. The discharge flow path R41 includes a groove on the back side of a convex portion that protrudes from the plate surface of the anode separator 24 toward the frame 21, and a convex portion that protrudes from the plate surface of the cathode separator 23 toward the frame 21 of the adjacent unit cell 2. It is formed between the groove on the back side of the part.

(Flow path of Comparative Example 1)
FIG. 4 is a plan view showing the vicinity of the through hole 242 of the anode separator 24 of Comparative Example 1. A protrusion 247 is provided around the through hole 242 through which fuel gas is discharged along the spring seal line L2s. The convex portion 247 is provided so as to surround the through hole 242.

Furthermore, another protrusion 248 is provided between the protrusion 247 and the end of the anode separator 24 along the spring seal line L0s. The convex portions 247 and 248 come into contact with the frame 21 and support the frame 21 with elastic force.

The opening H2 is provided on the anode channel portion 240 side of the convex portion 247. The opening H2 has a slit shape, for example, but is not limited to this. The opening H2 and the convex portion 247 are connected by convex portions 10 to 12 that protrude toward the frame 21 side. Further, the convex portion 247 and the through hole 242 are connected by convex portions 13 to 15 that protrude toward the frame 21 side.

Fuel gas is discharged from the MEGA 20 through the through hole 242 along the dotted arrow.

FIG. 5(a) is a cross-sectional view taken along line AA in FIG. 4. The cathode separator 23 has a protrusion 32 that protrudes on the opposite side from the protrusion 12 at a position facing the protrusion 12 . The grooves on the back side of each of the convex portions 12 and 32 constitute a lead-out passage R20 through which the fuel gas flows.

Further, the cathode separator 23 has a protrusion 35 that protrudes on the opposite side from the protrusion 15 at a position facing the protrusion 15 . The grooves on the back side of each convex portion 15, 35 constitute a discharge flow path R21 through which the fuel gas flows.

Further, the cathode separator 23 has a protrusion 237 that protrudes on the opposite side from the protrusion 247 at a position facing the protrusion 247 . The grooves on the back side of each of the convex portions 247 and 237 constitute an annular seal channel R2 through which the fuel gas flows. The seal channel R2 is an example of an annular channel surrounding the through hole 242. The outlet flow path R20 is an example of a first connection flow path that connects between the seal flow path R2 and the MEA 200, and the discharge flow path R21 is an example of a second connection flow path that connects between the through hole 242 and the seal flow path R2. This is an example of a road.

The fuel gas passes through the opening H2 from the MEGA 20, flows through the outlet channel R20, and enters the seal channel R2, as indicated by the arrow Fa. The fuel gas enters the discharge passage R21 from the seal passage R2 and is discharged from the through hole 242, as shown by arrow Fb.

FIG. 5(b) is a cross-sectional view taken along line BB in FIG. The cathode separator 23 has protrusions 30, 31, and 32 that protrude on the opposite side from the protrusions 10, 11, and 12, respectively, at positions facing the protrusions 10, 11, and 12. The grooves on the back side of the protrusions 10 and 30, the grooves on the back side of the protrusions 11 and 31, and the grooves on the back side of the protrusions 12 and 32 each constitute a lead-out channel R20 through which the fuel gas flows.

The respective lead-out channels R20 between the convex portions 10 and 30, between the convex portions 11 and 31, and between the convex portions 12 and 31 have the same height Ha and width Wa, and also have the same cross-sectional area.

FIG. 5(c) is a cross-sectional view taken along line CC in FIG. 4. The cathode separator 23 has protrusions 33, 34, and 35 that protrude on the opposite side from the protrusions 13, 14, and 15, respectively, at positions facing the protrusions 13, 14, and 15. The grooves on the back side of the protrusions 13 and 33, the grooves on the back side of the protrusions 14 and 34, and the grooves on the back side of the protrusions 15 and 35 each constitute a discharge flow path R21 through which the fuel gas flows.

The discharge channels R21 between the protrusions 13 and 33, between the protrusions 14 and 34, and between the protrusions 15 and 35 have the same height Hb and width Wb, and have the same cross-sectional area. Note that the cross section passing through the convex parts 10, 30, 13, and 33, the cross section passing through the convex parts 11, 31, 14, and 34, and the cross section passing through the convex parts 12, 32, 15, and 35 are the same as those in FIG.

(Flow path of Comparative Example 2)
FIG. 6 is a plan view showing the vicinity of the manifold hole of Comparative Example 2. In Comparative Example 2, as shown in FIG. 6, an annular flow path is provided to surround the manifold hole. The annular flow path functions as a flow path for gas and produced water, for example. Further, an outlet flange portion is provided closer to the manifold hole than the annular flow path. The outlet flange portion is provided from the viewpoint of preventing electrolytic corrosion. In FIG. 6, an outlet flange portion is provided around the entire outer edge of the manifold hole. Further, a comb-tooth channel (a comb-tooth-shaped channel composed of a plurality of channels) is provided between the annular channel and the outlet flange portion to connect the two. Further, a plurality of first connection channels are provided that connect between the annular channel and the membrane electrode assembly. An annular flow path and a comb-teeth flow path may be provided between the first connection flow path and the outlet flange portion. The annular channel, the first connection channel, and other matters are the same as those in Comparative Example 1 described above.

FIG. 7 is a cross-sectional view taken along line DD in FIG. 6. As shown in FIG. 7, a minute space exists between the cathode separator and the anode separator in the outlet flange portion, and water stays in the space. If water remains in the outlet flange portion, for example, after scavenging is completed, the remaining water may be sucked back into the comb-tooth flow path, causing blockage in the comb-tooth flow path. For example, when the temperature is low, water blocking the comb tooth flow path may freeze, and gas may not be supplied or discharged when the fuel cell is subsequently started. Further, the comb-tooth flow path may be a flow path configured with a cathode separator and an anode separator, or may be a flow path configured with a cathode separator or an anode separator and a sealing sheet.

(Flow path of example)
FIG. 8 is a plan view showing the vicinity of the manifold hole of the embodiment. In the embodiment, as shown in FIG. 8, an annular flow path, an outlet flange portion, and a comb-teeth flow path are provided around the manifold hole. These are the same as in Comparative Example 2. Further, as shown in FIG. 8, a flow path X is provided that connects the annular flow path and the outlet flange and guides the retained water accumulated in the outlet flange to the annular flow path. The flow path X is normally a flow path for sucking back the accumulated water. By providing the flow path X, a fuel cell can be obtained in which clogging of the comb-tooth flow path due to sucking back of accumulated water is suppressed. The flow path X may be a flow path configured with a cathode separator and an anode separator, or may be a flow path configured with a cathode separator or an anode separator and a sealing sheet. Although the width of the channel X is not particularly limited, it may be larger than the width of each channel constituting the comb-teeth channel. Although the installation position of the channel X is not particularly limited, it is preferably arranged between the position where accumulated water is most likely to occur and the comb-tooth channel. The position where stagnant water is most likely to occur can be determined from the positional relationship (especially in the vertical direction) where the fuel cell is installed. Furthermore, only one channel X may be provided, or a plurality of channels may be provided.

As shown in FIG. 8, a flow path Y may be provided that connects the annular flow path and the outlet flange portion and discharges the retained water guided to the annular flow path by the flow path X to the manifold hole. The flow path Y is normally a flow path for discharging accumulated water. The flow path Y may be a flow path configured with a cathode separator and an anode separator, or may be a flow path configured with a cathode separator or an anode separator and a sealing sheet. Although the width of the channel Y is not particularly limited, it may be larger than the width of each channel constituting the comb-teeth channel. The installation position of the flow path Y is not particularly limited. Further, only one flow path Y may be provided, or a plurality of flow paths Y may be provided.

The present disclosure is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and any configuration that has substantially the same technical idea as the claims of the present disclosure and provides similar effects is the present invention. within the technical scope of the disclosure.

2...Single cell (fuel cell)
21...Frame 23...Cathode separator (separator)
24...Anode separator (separator)
200...Membrane electrode assembly 231-234, 241-244...Through holes (manifold holes)
10 to 15, 11s, 14s, 247... Convex portion R20, R40... Derivation channel (first connection channel)
R21, R41...Discharge channel (second connection channel)

Claims (1)

A membrane electrode assembly that generates electricity using reactive gas,
a frame that holds the membrane electrode assembly;
a pair of separators that are joined with their plate surfaces facing each other and overlap the frame,
The pair of separators and the frame have manifold holes penetrating in the thickness direction and through which the reaction gas flows;
One of the pair of separators has a convex portion surrounding the manifold hole and supporting the frame,
Between the pair of separators, there is provided an annular flow path through which the reaction gas flows along the convex portion, an outlet flange portion disposed closer to the manifold hole than the annular flow path, and an annular flow path and the outlet. A comb-teeth channel connecting the flange portion is provided,
Furthermore, a flow path X is provided between the pair of separators to connect the annular flow path and the outlet flange portion, and to guide the accumulated water accumulated in the outlet flange portion to the annular flow path. battery.