Aging method of fuel battery stack

Abstract

To provide an aging of a fuel battery stack, capable of uniformly supplying water to each fuel battery cell.SOLUTION: An aging method of a fuel battery stack comprising a hydrogen gas manifold and an air manifold, comprises the steps of: inserting a pipe into at least one of the hydrogen gas manifold and the air manifold through an opening; supplying a gas into at least one of the hydrogen gas manifold and the air manifold through the opening; and supplying water into the pipe from the opening side in parallel with supplying the gas. The pipe is provided with a plurality of discharge ports which are arranged along a stacking direction and discharge water. The total area of each discharge port present per unit length of the pipe increases away from the opening.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a method for aging a fuel cell stack. [Background technology]

[0002] Patent Document 1 describes an aging method for a membrane electrode assembly (MEA). In this aging method, a heat pipe is used to increase the humidity of the gas supplied to the membrane electrode assembly, thereby activating the membrane electrode assembly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-131318 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned aging method has a problem in that the heat pipe consumes relatively large amounts of power. Therefore, the present inventors have developed a technology for activating membrane electrode assemblies by supplying water and gas separately without evaporating the water. If this technology can be applied to a fuel cell stack, it would be possible to activate the membrane electrode assemblies of multiple fuel cells simultaneously. In this case, it is conceivable to use a manifold provided in the fuel cell stack to supply water and gas to each fuel cell. However, in a fuel cell stack, the distance from the manifold opening to each fuel cell varies greatly. Therefore, in the fuel cell stack state, it is difficult to supply water evenly to multiple fuel cells.

[0005] In view of the above circumstances, the present specification provides a technique for supplying water evenly to each fuel cell unit during aging of a fuel cell stack. [Means for solving the problem]

[0006] The technology disclosed in this specification is embodied in a method for aging a fuel cell stack in which multiple fuel cells are stacked. In a first aspect, the fuel cell stack includes a hydrogen gas manifold extending from an opening located at one end of the fuel cell stack along the stacking direction of the multiple fuel cells and connected to each of the multiple fuel cells, and an air manifold extending from the opening located at the one end of the fuel cell stack along the stacking direction of the multiple fuel cells and connected to each of the multiple fuel cells. The aging method includes the steps of inserting a pipe into at least one of the hydrogen gas manifold and the air manifold from the opening, supplying gas from the opening to at least one of the hydrogen gas manifold and the air manifold, and supplying water into the pipe from the opening side in parallel with the gas supply step. The pipe has multiple outlets arranged along the stacking direction, each of which discharges the water. The total area of ​​the outlets per unit length of the pipe increases with increasing distance from the opening.

[0007] In the aging method described above, a pipe is inserted into a manifold (hydrogen gas manifold and / or air manifold) in the fuel cell stack, and water is supplied into the fuel cell cells using the pipe. The pipe is provided with multiple outlets along the stacking direction of the fuel cell cells, so water can be reliably supplied to fuel cell cells located far from the manifold opening. However, the water pressure of the water flowing through the pipe decreases with increasing distance from the manifold opening. As a result, the total area of ​​the outlets per unit length of the pipe increases with increasing distance from the manifold opening. This allows water to be discharged evenly from the pipe, regardless of the distance from the manifold opening, and water to be supplied evenly to each fuel cell cell.

[0008] In a second aspect, as in the first aspect, each of the plurality of outlets may have a larger area the farther it is from the opening. With this configuration, by increasing the area of ​​the outlets provided in the pipe, it is possible to increase the total area of ​​the outlets present per unit length of the pipe.

[0009] In a third aspect, in the first or second aspect, the number of outlets per unit length of the pipe may increase with increasing distance from the opening. By increasing the number of outlets provided in the pipe, the total area of ​​the outlets per unit length of the pipe can be increased.

[0010] In a fourth aspect, in any one of the first to third aspects, the step of inserting a pipe may include inserting a pipe into at least the air manifold. In this case, the step of supplying a gas may include supplying air to at least the air manifold. Generally, during aging of a fuel cell stack, the flow rate of air supplied to the air manifold is greater than the flow rate of hydrogen supplied to the hydrogen gas manifold. Therefore, supplying water from the air manifold allows water to be distributed more quickly over a wider area of ​​the fuel cell than supplying water from the hydrogen gas manifold.

[0011] In a fifth aspect, in any one of the first to fourth aspects, the pipe may have a plurality of flow paths each extending along the stacking direction. In this case, the plurality of flow paths may have a plurality of outlets provided in different ranges in the stacking direction. With this configuration, the total area of ​​the outlets present per unit length of the pipe can be increased by adjusting the positions of the outlets provided in the plurality of flow paths of the pipe. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram schematically showing the configuration of a fuel cell stack 10 to which an aging method according to an embodiment is applied. [Figure 2]1 is a flowchart showing an aging method according to an embodiment. [Figure 3] FIG. 2 is a diagram for explaining a pipe 28 used in the aging method of the embodiment. [Figure 4] FIG. 10 is a diagram for explaining a pipe 128 according to a modified example. [Figure 5] FIG. 10 is a diagram illustrating a pipe 228 according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] A fuel cell stack 10 to which an aging method of the embodiment is applied will be described with reference to the drawings. As shown in FIG. 1, the fuel cell stack 10 includes a plurality of fuel cell units 12. Each fuel cell unit 12 is arranged parallel to the Y axis and the Z axis, and the plurality of fuel cell units 12 are stacked along the X axis. As will be described in detail later, each fuel cell unit 12 is a component capable of generating electricity independently. The fuel cell stack 10 generates electricity by chemically reacting a fuel gas and an oxidizing gas within the plurality of fuel cell units 12. The fuel cell stack 10 of this embodiment uses hydrogen gas as the fuel gas and air as the oxidizing gas.

[0014] As shown in FIG. 1 , each of the multiple fuel cell cells 12 includes a membrane electrode and gas diffusion layer assembly (MEGA) 14, an anode-side separator 16, a cathode-side separator 18, and a support frame 20. Although not shown, the MEGA 14 is configured by sequentially stacking an anode-side gas diffusion layer, an anode electrode, an electrolyte membrane, a cathode electrode, and a cathode-side gas diffusion layer. The MEGA 14 is supported by a support frame 20 that surrounds its periphery. The MEGA 14 and the support frame 20 are disposed between the anode-side separator 16 and the cathode-side separator 18. The anode-side separator 16 and the cathode-side separator 18 are made of a gas-impermeable, electrically conductive material, for example, a plate made of a substrate containing titanium. The support frame 20 is configured of a resin material that is airtight and insulating.

[0015] 1, each of the separators 16, 18 and the support frame 20 has six manifold holes 22a-22f. The six manifold holes 22a-22f include a hydrogen gas supply manifold hole 22a, a hydrogen gas discharge manifold hole 22b, an air supply manifold hole 22c, an air discharge manifold hole 22d, a coolant supply manifold hole 22e, and a coolant discharge manifold hole 22f. Three supply manifold holes 22a, 22c, and 22e and three discharge manifold holes 22b, 22d, and 22f are arranged at both ends of each of the separators 16, 18 and the support frame 20 in the longitudinal direction.

[0016] 1, when multiple fuel cells 12 are stacked in the X-axis direction, the hydrogen gas supply manifold holes 22a formed in each separator 16, 18 and support frame 20 are connected to each other to form a hydrogen gas supply manifold 24a. Similarly, when multiple fuel cells 12 are stacked in the X-axis direction, the air supply manifold holes 22c and the cooling medium supply manifold holes 22e are connected to each other to form an air supply manifold 24c and a cooling medium supply manifold 24e. When multiple fuel cells 12 are stacked in the X-axis direction, the hydrogen gas discharge manifold holes 22b, the air discharge manifold holes 22d, and the cooling medium discharge manifold holes 22f are connected to each other to form a hydrogen gas discharge manifold 24b, an air discharge manifold 24d, and a cooling medium discharge manifold 24f, respectively.

[0017] In the fuel cell stack 10, hydrogen gas supplied to the hydrogen gas supply manifold 24a is supplied to each fuel cell 12. After passing through each fuel cell 12, the hydrogen gas passes through the hydrogen gas discharge manifold 24b and is discharged to the outside. Similarly, air supplied to the air supply manifold 24c is supplied to each fuel cell 12. After passing through each fuel cell 12, the air passes through the air discharge manifold 24d and is discharged to the outside. Furthermore, the cooling medium supplied to the cooling medium supply manifold 24e is supplied to each fuel cell 12. After passing through each fuel cell 12, the cooling medium passes through the cooling medium discharge manifold 24f and is discharged to the outside.

[0018] As described above, in the fuel cell stack 10 of this embodiment, six manifolds 24a-24f are formed, extending from the openings 26a-26f located at one end of the fuel cell stack 10 along the stacking direction (X-axis direction) of the fuel cell units 12. Each of the manifolds 24a-24f is connected to one of the plurality of fuel cell units 12.

[0019] 2 and 3, an aging method for the fuel cell stack 10 will be described. In this aging method, water and air are supplied from the air supply manifold 24c to each fuel cell 12. The aging method for the fuel cell stack 10 of this embodiment is carried out, for example, as part of the manufacturing process for the fuel cell stack 10.

[0020] 2, the aging method includes a step of inserting a pipe 28 into an air supply manifold 24c of the fuel cell stack 10 through an opening 26c (S10). In this embodiment, the length of the pipe 28 in the X-axis direction is longer than the length of the fuel cell stack 10 in the X-axis direction. The pipe 28 is provided with a plurality of outlets 30. The plurality of outlets 30 are arranged along the stacking direction of the fuel cell units 12 (i.e., the X-axis direction). Therefore, when water is supplied into the pipe 28, the water is discharged from each of the plurality of outlets 30.

[0021] Here, the multiple outlets 30 have different areas. Specifically, as shown in FIG. 3 , the area of ​​each of the multiple outlets 30 increases as the outlet 30 is located farther from the opening 26c of the air supply manifold 24c. As a result, the total area of ​​the outlets 30 per unit length of the pipe 28 increases with increasing distance from the opening 26c of the air supply manifold 24c. The shape of the outlets 30 is not particularly limited. For example, the outlet 30 may be circular. In this case, the diameter of each of the multiple outlets 30 may increase as the outlet 30 is located farther from the opening 26c of the air supply manifold 24c. Alternatively, the shape of the outlet 30 may be a slit. In this case, the slit width and / or length of each of the multiple outlets 30 may increase as the outlet 30 is located farther from the opening 26c of the air supply manifold 24c.

[0022] The aging method includes a step of supplying air to the air supply manifold 24c through the opening 26c (S12). As described above, the air supply manifold 24c is connected to each of the plurality of fuel cell units 12, and therefore the air supplied to the opening 26c of the air supply manifold 24c is supplied to each of the fuel cell units 12. In the aging method of this embodiment, in step S12, hydrogen gas is supplied to the hydrogen gas supply manifold 24a through the opening 26a.

[0023] The aging method includes a step of supplying water into the pipe 28 from the opening 26c side of the air supply manifold 24c (S14) in parallel with the step of supplying air (S12). In this step, the water supplied into the pipe 28 is discharged from the discharge port 30 into the air supply manifold 24c. As shown in Fig. 3, the water (WT) discharged into the air supply manifold 24c is supplied to each fuel cell 12 together with the air (AR) circulating inside the air supply manifold 24c.

[0024] As described above, the pipe 28 is provided with a plurality of discharge ports 30 along the stacking direction of the plurality of fuel cell units 12 (i.e., the X-axis direction). This allows water to be reliably supplied to fuel cell units 12 located away from the opening 26c of the air supply manifold 24c. However, the water pressure of the water flowing through the pipe 28 decreases with increasing distance from the opening 26c of the air supply manifold 24c. As a result, the total area of ​​the discharge ports 30 per unit length of the pipe 28 increases with increasing distance from the opening 26c of the air supply manifold 24c. This allows water to be discharged evenly from the pipe 28, and water to be supplied evenly to each of the fuel cell units 12, regardless of the distance from the opening 26c of the air supply manifold 24c.

[0025] Thereafter, power generation by the fuel cell stack 10 begins, and when the performance of the fuel cell 12 exceeds a predetermined performance, power generation by the fuel cell stack 10 is stopped. This completes the aging of the fuel cell stack 10.

[0026] In the above-described embodiment, the configuration of the pipe 28 can be modified as long as the total area of ​​the outlets 30 per unit length of the pipe 28 increases with increasing distance from the opening 26c of the air supply manifold 24c. For example, FIG. 4 shows a modified pipe 128. In this pipe 128, the number of outlets 130 per unit length of the pipe 128 increases with increasing distance from the opening 26c of the air supply manifold 24c. This configuration also allows the total area of ​​the outlets 130 per unit length of the pipe 128 to increase with increasing distance from the opening 26c of the air supply manifold 24c. Note that the multiple outlets 130 may have equal or different areas. For example, the area of ​​each of the multiple outlets 130 may increase or decrease with increasing distance from the opening 26c of the air supply manifold 24c. By varying both the area and the number of outlets 130 along the longitudinal direction of the pipe 128, the total area of ​​the outlets 130 present per unit length can be adjusted more freely.

[0027] FIG. 5 shows a pipe 228 according to another modification. The pipe 228 has a first flow path 228a and a second flow path 228b. The first flow path 228a and the second flow path 228b extend parallel to each other. The first flow path 228a and the second flow path 228b may be formed of a single pipe separated by a partition wall, or may be formed of a combination of two pipes. The first flow path 228a has a plurality of outlets 230a, and the second flow path 228b also has a plurality of outlets 230b. The plurality of outlets 230a in the first flow path 228a and the plurality of outlets 230b in the second flow path 228b are located in different ranges in the stacking direction of the fuel cell 12 (i.e., the X-axis direction). In this case, as shown in FIG. 5, the outlets 230a, 230b in each flow path 228a, 228b may have larger areas as they are located farther from the opening 26c. Alternatively, the number of outlets 230a, 230b present per unit length in each of the flow paths 228a, 228b may increase with increasing distance from the opening 26c. With this configuration, the ranges at which the outlets 230a, 230b are provided may be different between the multiple flow paths 228a, 228b, thereby increasing the total area of ​​the outlets 230a, 230b present per unit length of the pipe 228. Note that, as shown in Fig. 5, the length of the first flow path 228a in the X-axis direction may be shorter than or equal to the length of the second flow path 228b in the X-axis direction.

[0028] In the above-described embodiment, the pipe 28 is inserted into the air supply manifold 24c. However, the pipe 28 does not necessarily have to be inserted into the air supply manifold 24c. In another embodiment, the pipe 28 may be inserted into the air exhaust manifold 24d. In this case, air or other gas may be supplied to the air exhaust manifold 24d only for the purpose of supplying water to the fuel cell cells 12, without generating power in the fuel cell stack 10. Even with this configuration, water can be supplied evenly to each fuel cell cell 12 regardless of the distance from the opening 26d of the air exhaust manifold 24d. Each of the air supply manifold 24c and the air exhaust manifold 24d in this specification is an example of an air manifold in the present technology.

[0029] In yet another embodiment, the pipe 28 may be inserted into the hydrogen gas supply manifold 24a or the hydrogen gas discharge manifold 24b. Even with this configuration, water can be uniformly supplied to each of the fuel cell cells 12 regardless of the distance from the openings 26a, 26b of the hydrogen gas supply manifold 24a or the hydrogen gas discharge manifold 24b. Each of the hydrogen gas supply manifold 24a and the hydrogen gas discharge manifold 24b in this specification is an example of a hydrogen gas manifold in the present technology.

[0030] However, in general, the flow rate of air supplied to the air supply manifold 24c is greater than the flow rate of hydrogen supplied to the hydrogen gas supply manifold 24a during aging of the fuel cell stack 10. Therefore, supplying water from the air manifolds 24c and 24d allows water to be distributed more quickly over a wider area of ​​the fuel cell 12 than supplying water from the hydrogen gas manifolds 24a and 24b.

[0031] Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility either alone or in combination. [Explanation of symbols]

[0032] 10: fuel cell stack, 12: fuel cell unit, 16, 18: separator, 20: support frame, 22a: hydrogen gas supply manifold hole, 22b: hydrogen gas discharge manifold hole, 22c: air supply manifold hole, 22d: air discharge manifold hole, 22e: cooling medium supply manifold hole, 22f: cooling medium discharge manifold hole, 24a: hydrogen gas supply manifold, 24b: hydrogen gas discharge manifold, 24c: air supply manifold, 24d: air discharge manifold, 24e: cooling medium supply manifold, 24f: cooling medium discharge manifold, 26a-26f: openings, 28, 128, 228: pipes, 30, 130, 230a, 230b: discharge ports

Claims

1. A method for aging a fuel cell stack in which a plurality of fuel cell units are stacked, comprising: The fuel cell stack comprises: a hydrogen gas manifold extending from an opening located at one end of the fuel cell stack along the stacking direction of the plurality of fuel cell units and connected to each of the plurality of fuel cell units; an air manifold extending from an opening located at one end of the fuel cell stack along the stacking direction of the plurality of fuel cell units and connected to each of the plurality of fuel cell units; Equipped with The aging method includes: inserting a pipe into at least one of the hydrogen gas manifold and the air manifold through the opening; supplying gas to the at least one of the hydrogen gas manifold and the air manifold through the opening; supplying water into the pipe from the opening side in parallel with the gas supplying step; Equipped with The pipe is provided with a plurality of outlets that are arranged along the stacking direction and each outlet discharges the water, The total area of ​​the outlets per unit length of the pipe increases with increasing distance from the opening. Aging method.

2. The aging method according to claim 1 , wherein each of the plurality of ejection ports has an area that increases as it is positioned farther away from the opening.

3. 2. The aging method according to claim 1, wherein the number of outlets per unit length of the pipe increases with increasing distance from the opening.

4. In the step of inserting the pipe, the pipe is inserted into at least the air manifold; The aging method according to claim 1 , wherein the step of supplying a gas includes supplying air to at least the air manifold.

5. the pipe has a plurality of flow paths each extending along the stacking direction; The aging method according to claim 1 , wherein the plurality of ejection ports are provided in the plurality of flow paths in different ranges in the stacking direction.

Images