Fuel cell module

Abstract

The present invention relates to a fuel cell module comprising: a fuel cell stack; a fuel gas outlet manifold that extends in the stacking direction inside the fuel cell stack, is configured so that fuel gas that has passed through each of the fuel cell cells flows, and has a fuel gas discharge port in a first end surface of the fuel cell stack; an oxidant gas outlet manifold that extends in the stacking direction inside the fuel cell stack, is configured so that oxidant gas that has passed through each of the fuel cell cells flows, and has an oxidant gas discharge port in a second end surface of the fuel cell stack; and a drain flow path that connects the rear end of the fuel gas outlet manifold and the oxidant gas outlet.

Description

Technical Field

[0001] The technology disclosed in this specification relates to fuel cell modules. Background Technology

[0002] The fuel cell module disclosed in Japanese Patent Application Publication No. 2007-042538 comprises a fuel cell stack consisting of multiple stacked fuel cell cells. The fuel cell stack generates electricity by reacting fuel gas with oxidant gas. Inside the fuel cell stack are a fuel gas outlet manifold for discharging unreacted fuel gas and an oxidant gas outlet manifold for discharging unreacted oxidant gas. The fuel gas outlet manifold and oxidant gas outlet manifold extend along the stacking direction of the fuel cell cells. Furthermore, inside the fuel cell stack, water is generated by reacting fuel gas with oxidant gas. The generated water is discharged to the outside of the fuel cell stack through the fuel gas outlet manifold and oxidant gas outlet manifold. Summary of the Invention

[0003] Sometimes, in the stacking direction, the outlet of the fuel gas outlet manifold is provided on one end face of the fuel cell stack (hereinafter referred to as the first end face), and the outlet of the oxidant gas outlet manifold is provided on the other end face of the fuel cell stack (hereinafter referred to as the second end face). In this case, if the fuel cell module is tilted with the second end face being lower than the first end face, the fuel gas outlet manifold tilts so that its inner side faces downward, making it difficult to discharge generated water from the fuel gas outlet manifold. In this specification, a fuel cell module that facilitates the discharge of generated water from the fuel gas outlet manifold is proposed.

[0004] The first fuel cell module disclosed in this specification includes a fuel cell stack, a fuel gas outlet manifold, an oxidant gas outlet manifold, and a drainage path. The fuel cell stack comprises multiple stacked fuel cell cells, each having a first end face on one side of the stacking direction and a second end face on the other side. The fuel gas outlet manifold extends inside the fuel cell stack along the stacking direction, configured to allow fuel gas flowing through the fuel cell cells, and has a fuel gas outlet on the first end face. The oxidant gas outlet manifold extends inside the fuel cell stack along the stacking direction, configured to allow oxidant gas flowing through the fuel cell cells, and has an oxidant gas outlet on the second end face. The drainage path connects the inner end of the fuel gas outlet manifold to the oxidant gas outlet.

[0005] In this fuel cell module, if the fuel cell module is tilted with the second end face facing downwards compared to the first end face, then the fuel gas outlet manifold is tilted with its inner side facing downwards. Therefore, the generated water in the fuel gas outlet manifold is discharged to the oxidant gas outlet through the drainage path. Thus, in this fuel cell module, generated water is easily discharged from the fuel gas outlet manifold.

[0006] The second fuel cell module disclosed in this specification includes a fuel cell stack, a fuel gas outlet manifold, an oxidant gas outlet manifold, a gas-liquid separator, and a first drain pipe. The fuel cell stack is composed of multiple stacked fuel cell cells, each having a first end face on one side of the stacking direction and a second end face on the other side. The fuel gas outlet manifold extends inside the fuel cell stack along the stacking direction, configured to allow fuel gas flow through the fuel cell cells, and has a fuel gas outlet on the first end face. The oxidant gas outlet manifold extends inside the fuel cell stack along the stacking direction, configured to allow oxidant gas flow through the fuel cell cells, and has an oxidant gas outlet on the second end face. The gas-liquid separator separates water from the fuel gas discharged from the fuel gas outlet. The first drain pipe extends from the gas-liquid separator through the first end face into the oxidant gas outlet manifold and extends to the oxidant gas outlet.

[0007] In this fuel cell module, the first drain pipe, which discharges water separated by the gas-liquid separator, passes through the oxidant gas outlet manifold and extends to the oxidant gas outlet. Therefore, the routing path of the first drain pipe can be shortened, enabling miniaturization of the fuel cell module.

[0008] In the first fuel cell module described above, a drain pipe extending from the inner end of the oxidant gas outlet manifold to the oxidant gas outlet can be provided within the oxidant gas outlet manifold. The outlet of the drain path can be positioned upstream of the oxidant gas outlet manifold, above the outlet of the drain pipe.

[0009] This design allows for easy removal of generated water from the oxidant gas outlet manifold. Furthermore, it suppresses backflow in the drainage path.

[0010] In the second fuel cell module described above, a second drain pipe may be provided within the oxidant gas outlet manifold, extending from the inner end of the oxidant gas outlet manifold to the oxidant gas outlet. The outlet of the first drain pipe may be positioned upstream of the oxidant gas outlet manifold compared to the outlet of the second drain pipe.

[0011] Based on this configuration, the generated water in the oxidant gas outlet manifold can be easily discharged. Furthermore, backflow in the first drain pipe can be suppressed. Attached Figure Description

[0012] Hereinafter, the features, advantages, technical and industrial importance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals denote the same constituent elements, wherein:

[0013] Figure 1 This is a cross-sectional view of the fuel cell module of Example 1.

[0014] Figure 2 This is a diagram showing a tilted fuel cell module.

[0015] Figure 3 This is a cross-sectional view of the fuel cell module in Example 2.

[0016] Figure 4 This is a cross-sectional view of a fuel cell module combining embodiments 1 and 2. Detailed Implementation

[0017] [Example 1]

[0018] Figure 1 The fuel cell module 10a of Embodiment 1 shown is mounted on an electric vehicle. The fuel cell module 10a has a fuel cell stack 20. The fuel cell module 10a supplies electricity generated by the fuel cell stack 20 to the motor for driving the electric vehicle.

[0019] The fuel cell stack 20 has multiple stacked fuel cell cells 22 and end plates 24 and 26. The multiple fuel cell cells 22 are stacked with the stacking direction aligned with the horizontal direction of the electric vehicle. In the stacking direction, both ends of the stack of fuel cell cells 22 are covered by end plates 24 and 26. That is, the stack of fuel cell cells 22 is disposed between end plates 24 and 26 in the stacking direction. Hereinafter, the end face on the end plate 24 side of the two end faces of the fuel cell stack 20 will be referred to as the first end face 20a, and the end face on the end plate 26 side will be referred to as the second end face 20b.

[0020] Fuel gas and oxidant gas are supplied to each fuel cell cell 22 via manifolds (not shown). In this embodiment, the fuel gas is hydrogen, and the oxidant gas is air (more specifically, oxygen contained in air). Each fuel cell cell 22 generates electricity by reacting the fuel gas with the oxidant gas. Figure 1 As shown, a fuel gas outlet manifold 30 and an oxidant gas outlet manifold 40 are provided inside the fuel cell stack 20.

[0021] A fuel gas outlet manifold 30 passes through each fuel cell cell 22 and extends along the stacking direction inside the fuel cell stack 20. The fuel gas outlet manifold 30 has a fuel gas outlet 30a that passes through the end plate 24 and opens at the first end face 20a. The fuel gas outlet 30a is connected to a fuel gas discharge device 90 mounted on an electric vehicle. Fuel gas passing through each fuel cell cell 22 flows to the fuel gas outlet manifold 30. Additionally, in each fuel cell cell 22, water is generated through the reaction of fuel gas and oxidant gas. Each fuel cell cell 22 discharges the generated water along with the fuel gas into the fuel gas outlet manifold 30. Therefore, fuel gas and generated water flow from the fuel gas outlet manifold 30 to the fuel gas discharge device 90. The fuel gas discharge device 90 has a gas-liquid separator 90a. The fuel gas discharge device 90 separates the fuel gas from the generated water using the gas-liquid separator 90a and supplies the separated fuel gas back to the fuel cell stack 20. In addition, the fuel gas discharge device 90 will not be able to discharge the fuel gas and generated water from the generated water together to the outside of the electric vehicle.

[0022] An oxidant gas outlet manifold 40 extends along the stacking direction inside the fuel cell stack 20, passing through each fuel cell cell 22. The oxidant gas outlet manifold 40 has an oxidant gas outlet 40a that passes through the end plate 26 and opens at the second end face 20b. The oxidant gas outlet 40a is connected to an oxidant gas discharge device 92 mounted on an electric vehicle. Oxidant gas passing through each fuel cell cell 22 flows to the oxidant gas outlet manifold 40. Additionally, each fuel cell cell 22 discharges generated water along with the oxidant gas into the oxidant gas outlet manifold 40. Therefore, oxidant gas and generated water flow from the oxidant gas outlet manifold 40 to the oxidant gas discharge device 92. The oxidant gas discharge device 92 discharges the oxidant gas and generated water together to the outside of the electric vehicle.

[0023] A drain pipe 42 is provided inside the oxidant gas outlet manifold 40. The drain pipe 42 is a thinner pipe than the oxidant gas outlet manifold 40 and is open at both ends. The drain pipe 42 extends from the inner end (i.e., the first end face 20a side) of the oxidant gas outlet manifold 40 to the oxidant gas outlet 40a. If generated water accumulates at the inner end of the oxidant gas outlet manifold 40, the generated water is discharged to the oxidant gas outlet 40a through the drain pipe 42. In this way, the drain pipe 42 promotes the discharge of generated water within the oxidant gas outlet manifold 40.

[0024] A drainage path 32 is provided inside the end plate 26. The drainage path 32 is narrower than both the fuel gas outlet manifold 30 and the oxidant gas outlet manifold 40. The upstream end of the drainage path 32 is connected to the inner end of the fuel gas outlet manifold 30. The downstream end of the drainage path 32 is connected to the oxidant gas outlet 40a. The outlet 32a of the drainage path 32 is positioned upstream of the outlet 42a of the drain pipe 42 in the oxidant gas outlet manifold 40. A valve 34 is provided in the drainage path 32. The valve 34 is controlled by a control circuit 36.

[0025] The control circuit 36 ​​determines whether generated water needs to be discharged through the drainage path 32. For example, if the fuel cell module 10a tilts due to the tilting of an electric vehicle, etc. Figure 2 Since the second end face 20b is lower than the first end face 20a, the generated water in the fuel gas outlet manifold 30 is difficult to flow to the fuel gas outlet 30a. Therefore, when it becomes difficult for generated water to be discharged from the fuel gas outlet 30a, the control circuit 36 ​​determines that the generated water needs to be discharged through the drain path 32. When it is necessary to discharge generated water through the drain path 32, the control circuit 36 ​​determines whether the pressure in the fuel gas outlet manifold 30 is higher than the pressure in the oxidant gas outlet manifold 40. If the pressure in the fuel gas outlet manifold 30 is higher than the pressure in the oxidant gas outlet manifold 40, the control circuit 36 ​​opens the valve 34. Then, generated water is discharged from the fuel gas outlet manifold 30 to the oxidant gas outlet 40a through the drain path 32. Thus, even when it is difficult for generated water to be discharged from the fuel gas outlet 30a, the generated water in the fuel gas outlet manifold 30 can be properly discharged through the drain path 32. Furthermore, as described above, the outlet 32a of the drainage path 32 is positioned upstream of the outlet 42a of the drain pipe 42. This prevents the generated water discharged from the drain pipe 42 from flowing back into the drainage path 32. Additionally, when the pressure in the fuel gas outlet manifold 30 is lower than the pressure in the oxidant gas outlet manifold 40, the control circuit 36 ​​keeps the valve 34 closed, preventing the discharge of generated water and fuel gas via the drainage path 32. This prevents oxidant gas from flowing back from the oxidant gas outlet manifold 40 to the fuel gas outlet manifold 30 via the drainage path 32.

[0026] Furthermore, in Embodiment 1, when the pressure in the fuel gas outlet manifold 30 is lower than the pressure in the oxidant gas outlet manifold 40, the control circuit 36 ​​keeps the valve 34 closed. However, in this case, the control circuit 36 ​​can also control the gas supply devices to make the pressure in the fuel gas outlet manifold 30 higher than the pressure in the oxidant gas outlet manifold 40. For example, the control circuit 36 ​​can increase the pressure in the fuel gas outlet manifold 30 or decrease the pressure in the oxidant gas outlet manifold 40. After the pressure in the fuel gas outlet manifold 30 becomes higher than the pressure in the oxidant gas outlet manifold 40, the control circuit 36 ​​can open the valve 34. With this configuration, backflow of oxidant gas into the fuel gas outlet manifold 30 can also be prevented, and generated water can be discharged through the drain path 32.

[0027] Additionally, in Embodiment 1, a valve 34 is provided in the drain flow path 32. However, if backflow of oxidant gas from the oxidant gas outlet manifold 40 to the fuel gas outlet manifold 30 does not occur (e.g., if backflow is prevented by other mechanisms) or if there is no problem even if backflow occurs, the valve 34 may not be provided in the drain flow path 32. That is, in this case, the drain flow path 32 can always be open. With this configuration, generated water can also be discharged through the drain flow path 32.

[0028] [Example 2]

[0029] Figure 3 The fuel cell module 10b of Embodiment 2 shown is mounted in an electric vehicle. The fuel cell module 10b has a fuel cell stack 20. The fuel cell module 10b supplies electricity generated by the fuel cell stack 20 to the motor for driving the electric vehicle.

[0030] The fuel cell stack 20 has multiple stacked fuel cell cells 22 and end plates 24 and 26. The multiple fuel cell cells 22 are stacked with the stacking direction aligned with the horizontal direction of the electric vehicle. In the stacking direction, both ends of the stack of fuel cell cells 22 are covered by end plates 24 and 26. That is, the stack of fuel cell cells 22 is disposed between end plates 24 and 26 in the stacking direction. Hereinafter, the end face on the side of end plate 24 of the two end faces of the fuel cell stack 20 will be referred to as the first end face 20a, and the end face on the side of end plate 26 will be referred to as the second end face 20b.

[0031] Fuel gas and oxidant gas are supplied to each fuel cell cell 22 via manifolds (not shown). In this embodiment, the fuel gas is hydrogen, and the oxidant gas is air (more specifically, oxygen contained in air). Each fuel cell cell 22 generates electricity by reacting the fuel gas with the oxidant gas. Figure 3As shown, a fuel gas outlet manifold 30 and an oxidant gas outlet manifold 40 are provided inside the fuel cell stack 20.

[0032] A fuel gas outlet manifold 30 extends along the stacking direction inside the fuel cell stack 20, passing through each fuel cell cell 22. The fuel gas outlet manifold 30 has a fuel gas outlet 30a that passes through the end plate 24 and opens at a first end face 20a. A gas-liquid separator 90a is disposed near the first end face 20a. The fuel gas outlet 30a is connected to the gas-liquid separator 90a. Fuel gas passing through each fuel cell cell 22 flows to the fuel gas outlet manifold 30. Additionally, in each fuel cell cell 22, water is generated through the reaction of fuel gas and oxidant gas. Each fuel cell cell 22 discharges the generated water along with the fuel gas into the fuel gas outlet manifold 30. Therefore, fuel gas and generated water flow from the fuel gas outlet manifold 30 to the gas-liquid separator 90a. The gas-liquid separator 90a separates the fuel gas from the generated water and supplies the separated fuel gas back to the fuel cell stack 20.

[0033] An oxidant gas outlet manifold 40 extends along the stacking direction inside the fuel cell stack 20, passing through each fuel cell cell 22. The oxidant gas outlet manifold 40 has an oxidant gas outlet 40a that passes through the end plate 26 and opens at the second end face 20b. The oxidant gas outlet 40a is connected to an oxidant gas discharge device 92 mounted on an electric vehicle. Oxidant gas passing through each fuel cell cell 22 flows to the oxidant gas outlet manifold 40. Additionally, each fuel cell cell 22 discharges generated water along with the oxidant gas into the oxidant gas outlet manifold 40. Therefore, oxidant gas and generated water flow from the oxidant gas outlet manifold 40 to the oxidant gas discharge device 92. The oxidant gas discharge device 92 discharges the oxidant gas and generated water together to the outside of the electric vehicle.

[0034] A drain pipe 42 is provided inside the oxidant gas outlet manifold 40. The drain pipe 42 is a thinner pipe than the oxidant gas outlet manifold 40 and is open at both ends. The drain pipe 42 extends from the inner end (i.e., the first end face 20a side) of the oxidant gas outlet manifold 40 to the oxidant gas outlet 40a. If generated water accumulates at the inner end of the oxidant gas outlet manifold 40, the generated water is discharged to the oxidant gas outlet 40a through the drain pipe 42. In this way, the drain pipe 42 promotes the discharge of generated water within the oxidant gas outlet manifold 40.

[0035] A drain pipe 46 is connected to the gas-liquid separator 90a. The drain pipe 46 extends from the gas-liquid separator 90a through the first end face 20a and into the oxidant gas outlet manifold 40. The drain pipe 46 extends from the gas-liquid separator 90a to the oxidant gas outlet 40a. The outlet 46a of the drain pipe 46 is positioned upstream of the outlet 42a of the drain pipe 42 in the oxidant gas outlet manifold 40. As described above, the gas-liquid separator 90a separates fuel gas from the generated water. The gas-liquid separator 90a discharges the fuel gas and generated water that were not separated from the generated water together through the drain pipe 46 to the oxidant gas outlet 40a. A valve 48 is provided in the drain pipe 46. The valve 48 is controlled by a control circuit 49.

[0036] Control circuit 49 determines whether generated water needs to be discharged through drain pipe 46. If generated water needs to be discharged through drain pipe 46, control circuit 49 determines whether the pressure inside gas-liquid separator 90a is higher than the pressure inside oxidant gas outlet manifold 40. If the pressure inside gas-liquid separator 90a is higher than the pressure inside oxidant gas outlet manifold 40, control circuit 49 opens valve 48. Then, generated water and fuel gas are discharged from gas-liquid separator 90a through drain pipe 46 to oxidant gas outlet 40a. The generated water and fuel gas discharged from drain pipe 46 to oxidant gas outlet 40a, together with the generated water and oxidant gas in oxidant gas outlet manifold 40, are discharged to the outside of the electric vehicle by oxidant gas discharge device 92. As described above, outlet 46a of drain pipe 46 is positioned upstream of outlet 42a of drain pipe 42. This prevents backflow of generated water discharged from drain pipe 42 into drain pipe 46. Furthermore, when the pressure inside the gas-liquid separator 90a is lower than the pressure inside the oxidant gas outlet manifold 40, the control circuit 49 keeps the valve 48 closed, preventing the discharge of generated water and fuel gas via the drain pipe 46. This prevents oxidant gas from flowing back from the oxidant gas outlet manifold 40 to the gas-liquid separator 90a via the drain pipe 46.

[0037] As explained above, in Embodiment 2, the drain pipe 46, which discharges water and fuel gas from the gas-liquid separator 90a, passes through the end plate 24 and is inserted into the oxidant gas outlet manifold 40. With this configuration, compared to the case where the drain pipe 46 is disposed outside the fuel cell stack 20, the placement path of the drain pipe 46 can be shortened, allowing for miniaturization of the fuel cell module 10b.

[0038] Furthermore, in Embodiment 2, when the pressure inside the gas-liquid separator 90a is lower than the pressure inside the oxidant gas outlet manifold 40, the control circuit 49 keeps the valve 48 closed. However, in this case, the control circuit 49 can also control the gas supply devices to make the pressure inside the gas-liquid separator 90a higher than the pressure inside the oxidant gas outlet manifold 40. For example, the pressure inside the gas-liquid separator 90a can be increased, or the pressure inside the oxidant gas outlet manifold 40 can be decreased. After the pressure inside the gas-liquid separator 90a becomes higher than the pressure inside the oxidant gas outlet manifold 40, the control circuit 49 can open the valve 48. With this configuration, backflow of oxidant gas into the gas-liquid separator 90a can also be prevented, and generated water can be discharged through the drain pipe 46.

[0039] Additionally, in Embodiment 2, a valve 48 is provided in the drain pipe 46. However, if backflow of oxidant gas from the oxidant gas outlet manifold 40 to the gas-liquid separator 90a does not occur (e.g., if backflow is prevented by other mechanisms), the valve 48 may not be provided in the drain pipe 46. That is, in this case, the drain pipe 46 can always be open.

[0040] Alternatively, it can be like Figure 4 As shown, Examples 1 and 2 are combined.

[0041] The embodiments have been described in detail above, but these are merely illustrative and do not limit the scope of protection claimed in this application. The technology described in the scope of protection of this application includes technologies obtained by various modifications and alterations to the specific examples described above. The technical elements described in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the scope of protection claimed at the time of application. In addition, the technology illustrated in this specification or drawings achieves multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

Claims

1. A fuel cell module, wherein, Having: a fuel cell stack composed of a plurality of fuel cell elements stacked, having a first end face on one side in a stacking direction of the plurality of fuel cell elements, and having a second end face on the other side in the stacking direction; a fuel gas outlet manifold extending inside the fuel cell stack along the stacking direction, configured to allow fuel gas that has passed through the respective fuel cell elements to flow, and having a fuel gas discharge port at the first end face; an oxidizing agent gas outlet manifold extending inside the fuel cell stack along the stacking direction, configured to allow oxidizing agent gas that has passed through the respective fuel cell elements to flow, and having an oxidizing agent gas discharge port at the second end face; and a drain flow path connecting an end portion on an inner side of the fuel gas outlet manifold and the oxidizing agent gas discharge port.

2. The fuel cell module according to claim 1, wherein a drain pipe extending from the end portion on the inner side of the oxidizing agent gas outlet manifold to the oxidizing agent gas discharge port is provided within the oxidizing agent gas outlet manifold, an outlet of the drain flow path is disposed at a position further upstream in the oxidizing agent gas outlet manifold than an outlet of the drain pipe.

3. A fuel cell module, wherein, Having: a fuel cell stack composed of a plurality of fuel cell elements stacked, having a first end face on one side in a stacking direction of the plurality of fuel cell elements, and having a second end face on the other side in the stacking direction; a fuel gas outlet manifold extending inside the fuel cell stack along the stacking direction, configured to allow fuel gas that has passed through the respective fuel cell elements to flow, and having a fuel gas discharge port at the first end face; an oxidizing agent gas outlet manifold extending inside the fuel cell stack along the stacking direction, configured to allow oxidizing agent gas that has passed through the respective fuel cell elements to flow, and having an oxidizing agent gas discharge port at the second end face; a gas-liquid separator that separates water from fuel gas discharged by the fuel gas discharge port; and a first drain pipe that is inserted into the oxidizing agent gas outlet manifold through the first end face from the gas-liquid separator, and extends to the oxidizing agent gas discharge port.

4. The fuel cell module according to claim 3, wherein a second drain pipe extending from the end portion on the inner side of the oxidizing agent gas outlet manifold to the oxidizing agent gas discharge port is provided within the oxidizing agent gas outlet manifold, an outlet of the first drain pipe is disposed at a position further upstream in the oxidizing agent gas outlet manifold than an outlet of the second drain pipe.

Images