Fuel cell module

Abstract

We propose a technology to suppress backflow in drainage channels. [Solution] The fuel cell module comprises a fuel cell stack composed of a plurality of stacked fuel cell cells, a fuel gas outlet manifold extending along the stacking direction inside the fuel cell stack through which fuel gas that has passed through each fuel cell flows, an oxidant gas outlet manifold extending along the stacking direction inside the fuel cell stack through which oxidant gas that has passed through each fuel cell flows, a discharge channel for discharging oxidant gas from the oxidant gas outlet manifold, a pressure regulating valve provided in the discharge channel which lowers the pressure in the discharge channel downstream of the pressure regulating valve to a level lower than the pressure in the oxidant gas outlet manifold, and a water drain channel which discharges water generated in the fuel cell cells from the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a fuel cell module.

Background Art

[0002] The fuel cell module disclosed in Patent Document 1 has a fuel cell stack formed by stacking a plurality of fuel cells. The fuel cell stack generates electricity by reacting a fuel gas and an oxidant gas. Inside the fuel cell stack, a fuel gas outlet manifold for discharging the fuel gas that has passed through the fuel cells is provided. Also, inside the fuel cell stack, an oxidant gas outlet manifold for discharging the oxidant gas that has passed through the fuel cells is provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the fuel cell stack, water is generated by the reaction of the fuel gas and the oxidant gas (hereinafter referred to as generated water). The generated water is discharged to the outside of the fuel cell stack through the fuel gas outlet manifold and the oxidant gas outlet manifold.

[0005] The fuel cell module may be provided with a drainage channel for discharging the generated water from the fuel gas outlet manifold to the oxidant gas outlet manifold. When the drainage channel is provided, the discharge paths of the generated water can be consolidated at the fuel gas outlet manifold and the oxidant gas outlet manifold. However, when the drainage channel is provided in this way, the generated water and the oxidant gas may flow backward in the drainage channel. In this specification, a technique for suppressing the backward flow in the drainage channel is proposed.

Means for Solving the Problems

[0006] (Aspect 1) The fuel cell module disclosed herein comprises a fuel cell stack composed of a plurality of stacked fuel cell cells; a fuel gas outlet manifold extending along the stacking direction within the fuel cell stack and through which fuel gas that has passed through each fuel cell flows; an oxidant gas outlet manifold extending along the stacking direction within the fuel cell stack and through which oxidant gas that has passed through each fuel cell flows; a discharge channel for discharging oxidant gas from the oxidant gas outlet manifold; a pressure regulating valve provided in the discharge channel, which lowers the pressure in the discharge channel downstream of the pressure regulating valve to a level lower than the pressure in the oxidant gas outlet manifold; and a drain channel for discharging water generated in the fuel cell from the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve.

[0007] In the fuel cell module described above, the water drainage channel discharges the generated water from the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve. The pressure in the discharge channel downstream of the pressure regulating valve is controlled by the pressure regulating valve to be lower than the pressure in the oxidizer gas outlet manifold. As a result, backflow in the water drainage channel can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the fuel cell module of Example 1. [Figure 2] This is a schematic diagram of the fuel cell module in Example 2. [Figure 3] This is a schematic diagram of the fuel cell module of Example 3. [Figure 4] This is a schematic diagram of the fuel cell module of Example 4. [Figure 5] This is a schematic diagram of the fuel cell module of Example 5. [Modes for carrying out the invention]

[0009] Following the above description of Embodiment 1, additional configurations of the fuel cell system disclosed herein will be described below. (Aspect 2) A fuel cell module according to Embodiment 1, further comprising a gas-liquid separator, wherein the fuel cell stack has a first end face on one side in the stacking direction and a second end face on the other side in the stacking direction, the fuel gas outlet manifold has a fuel gas outlet on the first end face, the oxidizer gas outlet manifold has an oxidizer gas outlet on the second end face connected to the discharge channel, the gas-liquid separator separates water from the fuel gas discharged from the fuel gas outlet, the water drain channel is configured to discharge the water separated by the gas-liquid separator to the discharge channel downstream of the pressure regulating valve, and extends from the gas-liquid separator through the first end face, through the oxidizer gas outlet manifold, to the discharge channel. (Aspect 3) A fuel cell module according to embodiment 1 or 2, wherein the fuel cell stack has a first end face on one side in the stacking direction and a second end face on the other side in the stacking direction, the fuel gas outlet manifold has a fuel gas outlet on its first end face, the oxidizer gas outlet manifold has an oxidizer gas outlet on its second end face that is connected to the discharge channel, and the drain channel extends from the far end of the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve. (Aspect 4) A fuel cell module according to any one of embodiments 1 to 3, wherein a drain pipe extending along the stacking direction is provided in the oxidizer gas outlet manifold.

[0010] According to embodiment 2, the drain channel for discharging the water separated by the gas-liquid separator extends through the oxidizer gas outlet manifold to the discharge channel. Therefore, the length of the drain channel can be shortened, and the fuel cell module can be miniaturized.

[0011] According to embodiment 3, water accumulated at the far end of the fuel gas outlet manifold is discharged through the drain channel to the discharge channel downstream of the pressure regulating valve. Therefore, the discharge of water within the fuel gas outlet manifold is facilitated by the drain channel.

[0012] According to embodiment 4, the generated water in the oxidizer gas outlet manifold can be easily discharged.

[0013] (Example 1) The fuel cell module 100 of Embodiment 1 shown in Figure 1 is mounted on a device that uses a fuel cell as a power source (for example, a fuel cell vehicle). The fuel cell module 100 has a fuel cell stack 10. The fuel cell module 100 supplies the electricity generated by the fuel cell stack 10 to a motor and the like.

[0014] The fuel cell stack 10 has a plurality of stacked fuel cell cells 12, an end plate 14, and an end plate 16. One end of the stack of fuel cell cells 12 is covered by the end plate 14, and the other end of the stack of fuel cell cells 12 is covered by the end plate 16. That is, the stack of fuel cell cells 12 is sandwiched between the end plate 14 and the end plate 16 in the stacking direction. In the following, the end face on the end plate 14 side of the fuel cell stack 10 will be referred to as the first end face 10a, and the end face on the end plate 16 side will be referred to as the second end face 10b.

[0015] Each fuel cell 12 is supplied with an oxidizing gas (e.g., air) from a manifold (not shown) and a fuel gas (e.g., hydrogen) from another manifold (not shown). Each fuel cell 12 generates electricity by reacting the fuel gas and the oxidizing gas. In addition, water is produced in each fuel cell 12 as a result of this reaction (hereinafter referred to as generated water). As shown in Figure 1, a fuel gas outlet manifold 20 and an oxidizing gas outlet manifold 22 are provided inside the fuel cell stack 10.

[0016] The fuel gas outlet manifold 20 penetrates through each fuel cell 12 and the end plate 14 and extends along the stacking direction inside the fuel cell stack 10. The fuel gas outlet manifold 20 has a fuel gas discharge port 20a. The fuel gas discharge port 20a opens to the first end face 10a. The fuel gas outlet manifold 20 allows the fuel gas that has passed through each fuel cell 12 to flow. The fuel cell 12 discharges the generated water together with the fuel gas to the fuel gas outlet manifold 20. The generated water and the fuel gas flow inside the fuel gas outlet manifold 20 and are discharged to the outside of the fuel cell stack 10 through the fuel gas discharge port 20a.

[0017] The oxidant gas outlet manifold 22 penetrates through each fuel cell 12 and the end plate 16 and extends along the stacking direction inside the fuel cell stack 10. The oxidant gas outlet manifold 22 has an oxidant gas discharge port 22a. The oxidant gas discharge port 22a opens to the second end face 10b. The oxidant gas outlet manifold 22 allows the oxidant gas that has passed through each fuel cell 12 to flow. The fuel cell 12 discharges the generated water together with the oxidant gas to the oxidant gas outlet manifold 22. The oxidant gas and the generated water flow inside the oxidant gas outlet manifold 22 toward the oxidant gas discharge port 22a.

[0018] A drain pipe 30 is provided inside the oxidant gas outlet manifold 22. The drain pipe 30 is a thinner pipe than the oxidant gas outlet manifold 22 and both ends thereof are open. The drain pipe 30 extends from the end on the back side (i.e., the side of the first end face 10a) of the oxidant gas outlet manifold 22 to the oxidant gas discharge port 22a. That is, the drain pipe 30 extends along the stacking direction of the fuel cells 12. When the generated water accumulates at the end on the back side of the oxidant gas outlet manifold 22, the generated water is discharged to the oxidant gas discharge port 22a through the drain pipe 30. Therefore, inside the oxidant gas outlet manifold 22, the discharge of the generated water is promoted by the drain pipe 30.

[0019] The fuel cell module 100 has an exhaust passage 24. The upstream end of the exhaust passage 24 is connected to the oxidant gas discharge port 22a. The oxidant gas and the generated water flowing in the oxidant gas outlet manifold 22 are discharged to the outside of the fuel cell stack 10 through the exhaust passage 24. A pressure regulating valve 26 is provided in the exhaust passage 24. The fuel cell module 100 has a control device 40. The control device 40 controls the pressure regulating valve 26. The control device 40 controls the pressure regulating valve 26 so that the pressure in the exhaust passage 24 downstream of the pressure regulating valve 26 is lower than the pressure in the oxidant gas outlet manifold 22.

[0020] The fuel cell module 100 has a drain passage 32. The drain passage 32 is a passage narrower than the fuel gas outlet manifold 20 and the oxidant gas outlet manifold 22. The upstream end of the drain passage 32 is connected to the end on the inner side (i.e., the second end face 10b side) of the oxidant gas outlet manifold 22. The drain passage 32 passes through the end plate 16 and extends to the exhaust passage 24. The downstream end of the drain passage 32 is connected to the exhaust passage 24 downstream of the pressure regulating valve 26. A valve 34 is provided in the drain passage 32. The valve 34 opens and closes the passage of the drain passage 32. When generated water accumulates at the inner end of the fuel gas outlet manifold 20 when the valve 34 is in the open state, the generated water is discharged to the exhaust passage 24 through the drain passage 32. The drain passage 32 promotes the discharge of the generated water from the fuel gas outlet manifold 20.

[0021] During operation of the fuel cell module 100, as described above, fuel gas and generated water are discharged from the fuel gas outlet manifold 20 to the outside of the fuel cell stack 10 via the fuel gas outlet 20a, and oxidant gas and generated water are discharged from the oxidant gas outlet manifold 22 to the outside of the fuel cell stack 10 via the discharge channel 24. Also, during operation of the fuel cell module 100, the valve 34 is controlled to be in the open state. Therefore, when generated water accumulates in the fuel gas outlet manifold 20, the generated water in the fuel gas outlet manifold 20 is discharged to the discharge channel 24 via the drain channel 32. At this time, the pressure in the discharge channel 24 downstream of the pressure regulating valve 26 is controlled to be lower than the pressure in the oxidant gas outlet manifold 22 by the pressure regulating valve 26, so the pressure at the outlet of the drain channel 32 is low. Therefore, backflow of oxidant gas and generated water from the discharge channel 24 to the drain channel 32 is prevented. As a result, the generated water in the fuel gas outlet manifold 20 is preferably discharged to the discharge channel 24.

[0022] (Example 2) Figure 2 shows the fuel cell module 102 of Example 2. In Figure 2, the same symbols are used for parts that are common to Figure 1. The fuel cell module 102 of Example 2 differs from Example 1 in that it does not have a drainage channel 32, but has a drainage pipe 44, a gas-liquid separator 42, and a drainage channel 36. In other respects, the fuel cell module 102 of Example 2 is the same as that of Example 1.

[0023] The gas-liquid separator 42 is located next to the end plate 14. The gas-liquid separator 42 is connected to the fuel gas outlet 20a. The generated water and fuel gas discharged from each fuel cell cell 12 flow through the fuel gas outlet manifold 20 and are discharged to the gas-liquid separator 42 via the fuel gas outlet 20a. The gas-liquid separator 42 separates the fuel gas from the generated water. The fuel gas separated from the generated water by the gas-liquid separator 42 is resupplied to the fuel cell stack 10 through a fuel gas supply path (not shown).

[0024] The drain pipe 44 is located within the fuel gas outlet manifold 20. The drain pipe 44 is thinner than the fuel gas outlet manifold 20 and is open at both ends. The drain pipe 44 extends from the rear end (i.e., the second end face 10b side) of the fuel gas outlet manifold 20 to the fuel gas outlet 20a. In other words, the drain pipe 44 extends along the stacking direction of the fuel cell cells 12. When generated water accumulates at the rear end of the fuel gas outlet manifold 20, the generated water flows through the drain pipe 44 and is discharged to the gas-liquid separator 42 via the fuel gas outlet 20a. Within the fuel gas outlet manifold 20, the discharge of generated water is facilitated by the drain pipe 44.

[0025] The fuel cell module 102 has a drain channel 36 made of a narrow tube. The drain channel 36 is narrower than the fuel gas outlet manifold 20 and the oxidizer gas outlet manifold 22. The upstream end of the drain channel 36 is connected to the gas-liquid separator 42. The drain channel 36 extends from the gas-liquid separator 42 through the first end face 10a into the oxidizer gas outlet manifold 22. The drain channel 36 extends inside the oxidizer gas outlet manifold 22 to the oxidizer gas outlet 22a. The drain channel 36 is drawn out to the outside from the discharge channel 24. The downstream end of the drain channel 36 is connected to the discharge channel 24 downstream of the pressure regulating valve 26. A valve 38 is provided in the drain channel 36. The valve 38 opens and closes the flow path of the drain channel 36. When the valve 38 is open, the generated water separated from the fuel gas in the gas-liquid separator 42 is discharged to the discharge channel 24 via the drain channel 36.

[0026] During the operation of the fuel cell module 102 in Example 2, oxidant gas and generated water are discharged from the oxidant gas outlet manifold 22 to the outside of the fuel cell stack 10 via the discharge channel 24, similar to Example 1. Also, during the operation of the fuel cell module 102, as described above, fuel gas and generated water are discharged from the fuel gas outlet manifold 20 to the gas-liquid separator 42. Furthermore, during the operation of the fuel cell module 102, the valve 38 is controlled to be in the open state. As a result, the generated water in the gas-liquid separator 42 is discharged to the discharge channel 24 via the water drain channel 36. That is, the water drain channel 36 discharges the generated water generated in the fuel cell cell 12 from the fuel gas outlet manifold 20 to the discharge channel 24 downstream of the pressure regulating valve 26. Since the pressure in the discharge channel 24 downstream of the pressure regulating valve 26 is controlled by the pressure regulating valve 26 to be lower than the pressure in the oxidant gas outlet manifold 22, the pressure at the outlet of the water drain channel 36 is low. Therefore, backflow of oxidizing agent gas and generated water from the discharge channel 24 to the drain channel 36 is prevented.

[0027] In Example 2, as described above, the drainage channel 36 is provided to pass through the oxidizer gas outlet manifold 22. With this configuration, the length of the drainage channel 36 can be shortened compared to the case where the drainage channel 36 is provided outside the fuel cell stack 10, and the fuel cell module 102 can be miniaturized.

[0028] (Example 3) The fuel cell module 103 of Embodiment 3 shown in Figure 3 differs from that of Embodiment 2 in its pressure regulating valve. Also, the arrangement of the downstream portion of the drainage channel 36 differs from that of Embodiment 2. The other components of the fuel cell module 103 of Embodiment 3 are the same as those of Embodiment 2.

[0029] In Example 3, the fuel cell module 103 has a pressure regulating valve 50. The pressure regulating valve 50 is a butterfly valve having a valve body 52. ​​The pressure regulating valve 50 is housed in a housing 54. The downstream portion of the drainage channel 36 extends through the housing 54 to the discharge channel 24. In Example 3 as well, the downstream end of the drainage channel 36 is connected to the discharge channel 24 downstream of the pressure regulating valve. Therefore, the generated water can be discharged through the drainage channel 36 while preventing backflow in the drainage channel 36.

[0030] (Example 4) In the above-described Embodiment 3, the downstream portion of the drain channel 36 extended through the housing 54 to the discharge channel 24. In contrast, as shown in Figure 4, in the fuel cell module 104 of Embodiment 4, the drain channel 36 extends from the gas-liquid separator 42 through the oxidizer gas outlet manifold 22 and the valve body 52 to the discharge channel 24. In Embodiment 4 as well, the downstream end of the drain channel 36 is connected to the discharge channel 24 downstream of the pressure regulating valve. Therefore, the generated water can be discharged through the drain channel 36 while preventing backflow in the drain channel 36.

[0031] (Example 5) The fuel cell module 105 of Example 5 shown in Figure 5 is a combination of Examples 1 and 2. In this case, the drain pipe 44 does not necessarily have to be provided.

[0032] In Examples 1 to 5, the fuel gas outlet 20a opened on the first end face 10a. However, the fuel gas outlet 20a may also open on the second end face 10b. Also, in Examples 1 and 2, the oxidizer gas outlet 22a opened on the second end face 10b. However, the oxidizer gas outlet 22a may also open on the first end face 10a.

[0033] In Examples 1 to 5, a drain pipe 30 was provided inside the oxidizer gas outlet manifold 22. However, the drain pipe 30 does not necessarily have to be provided inside the oxidizer gas outlet manifold 22.

[0034] In Examples 2 to 4, a drain pipe 44 was provided inside the fuel gas outlet manifold 20. However, the drain pipe 44 does not necessarily have to be provided inside the fuel gas outlet manifold 20.

[0035] In Examples 1 and 5, the drainage channel 32 had a valve 34. However, the drainage channel 32 does not need to have a valve 34. In this case, the drainage channel 32 may always be open.

[0036] In Examples 2-5, the drainage channel 36 had a valve 38. However, the drainage channel 36 does not need to have a valve 38. In this case, the drainage channel 36 may always be open.

[0037] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. [Explanation of Symbols]

[0038] 10: Fuel cell stack, 10a: First end face, 10b: Second end face, 12: Fuel cell cell, 20: Fuel gas outlet manifold, 20a: Fuel gas outlet, 22: Oxidizer gas outlet manifold, 22a: Oxidizer gas outlet, 24: Discharge channel, 26, 50: Pressure regulating valves, 30, 44: Water drain pipes, 32, 36: Water drain channels, 42: Gas-liquid separator, 100, 102, 103, 104, 105: Fuel cell modules

Claims

1. It is a fuel cell module, A fuel cell stack, which consists of multiple stacked fuel cell cells, The fuel cell stack extends along the stacking direction, and a fuel gas outlet manifold through which the fuel gas that has passed through each fuel cell flows, An oxidizer gas outlet manifold extends along the stacking direction inside the fuel cell stack, through which the oxidizer gas that has passed through each fuel cell flows, A discharge channel for discharging oxidizing gas from the oxidizing gas outlet manifold, A pressure regulating valve provided in the discharge passage, wherein the pressure regulating valve lowers the pressure in the discharge passage downstream of the pressure regulating valve to a level lower than the pressure in the oxidizer gas outlet manifold, A drain channel for discharging water generated in the fuel cell from the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve, A fuel cell module equipped with the following features.

2. It is further equipped with a gas-liquid separator, The fuel cell stack has a first end face on one side in the stacking direction and a second end face on the other side in the stacking direction. The fuel gas outlet manifold has a fuel gas outlet on its first end face, The oxidizer gas outlet manifold has an oxidizer gas outlet connected to the discharge channel on its second end face, The gas-liquid separator separates water from the fuel gas discharged from the fuel gas outlet. The drain channel is configured to discharge the water separated by the gas-liquid separator into the discharge channel downstream of the pressure regulating valve, and extends from the gas-liquid separator through the first end face, through the oxidizer gas outlet manifold, to the discharge channel. The fuel cell module according to claim 1.

3. The fuel cell stack has a first end face on one side in the stacking direction and a second end face on the other side in the stacking direction. The fuel gas outlet manifold has a fuel gas outlet on its first end face, The oxidizer gas outlet manifold has an oxidizer gas outlet connected to the discharge channel on its second end face, The drainage channel extends from the far end of the fuel gas outlet manifold to the discharge channel downstream of the pressure regulating valve. The fuel cell module according to claim 1.

4. The fuel cell module according to any one of claims 1 to 3, wherein a drain pipe extending along the stacking direction is provided in the oxidizer gas outlet manifold.

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