Fuel cell module

Abstract

A fuel cell module comprises a fuel cell stack; a fuel gas outlet manifold extending within the fuel cell stack in one stacking direction, configured such that a fuel gas flowing through each of the fuel cell cells flows through the fuel gas outlet manifold and includes a fuel gas outlet opening at a first end face of the fuel cell stack; an oxidation gas outlet manifold extending within the fuel cell stack in the stacking direction, configured such that an oxidation gas flowing through each of the fuel cell cells flows through the oxidation gas outlet manifold and includes an oxidation gas outlet opening at a second end face of the fuel cell stack; and a water drain channel connecting an upstream end section of the fuel gas outlet manifold and the oxidation gas outlet opening.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The technology disclosed in the present description relates to a fuel cell module. 2. Description of the state of the art

[0002] A fuel cell module disclosed in Japanese patent application JP 2007-042538A comprises a fuel cell stack consisting of a plurality of stacked fuel cells. The fuel cell stack generates electricity through the reaction of a fuel gas with an oxidizer gas. Within the fuel cell stack are a fuel gas outlet distributor for discharging unreacted fuel gas and an oxidizer gas outlet distributor for discharging unreacted oxidizer gas. The fuel gas outlet distributor and the oxidizer gas outlet distributor extend in the direction of the fuel cell stack. Furthermore, water is produced within the fuel cell stack by the reaction between the fuel gas and the oxidizer gas. The produced water is discharged from the fuel cell stack to the outside via the fuel gas outlet distributor and the oxidizer gas outlet distributor. SUMMARY OF THE INVENTION

[0003] In the stacking direction, an outlet of the fuel gas outlet manifold can be provided at one end face (hereinafter referred to as the first end face) of the fuel cell stack, and an outlet of the oxidation gas outlet manifold can be provided at the other end face (hereinafter referred to as the second end face) of the fuel cell stack. In this case, if the fuel cell module is tilted in a direction where the second end face passes below the first end face, the fuel gas outlet manifold will tilt such that an upstream section of the fuel gas outlet manifold will point downwards. Therefore, it is difficult to drain the generated water from the fuel gas outlet manifold. The present description proposes a fuel cell module in which the generated water can be easily drained from the fuel gas outlet manifold.

[0004] A first fuel cell module disclosed in the present description comprises a fuel cell stack, a fuel gas outlet distributor, an oxidation gas outlet distributor, and a water drain channel. The fuel cell stack consists of several stacked fuel cell cells and comprises a first end face on one side in the stacking direction of the fuel cell cells and a second end face on the other side in the stacking direction. The fuel gas outlet distributor extends within the fuel cell stack in the stacking direction, is configured such that a fuel gas that has flowed through each of the fuel cell cells flows through the fuel gas outlet distributor, and includes a fuel gas outlet opening at the first end face.The oxidation gas outlet manifold extends within the fuel cell stack in the stack direction, is configured so that any oxidation gas flowing through each of the fuel cell cells flows through the oxidation gas outlet manifold, and includes an oxidation gas outlet opening at the second end face. The water drain channel connects an upstream end section of the fuel gas outlet manifold to the oxidation gas outlet opening.

[0005] When the fuel cell module is tilted and the second end face moves below the first, the fuel gas outlet manifold tilts, and the upstream section of the fuel gas outlet manifold descends. Consequently, the water generated in the fuel gas outlet manifold is drained through the water drain channel to the oxidation gas outlet opening. Therefore, it is easy to remove the generated water from the fuel gas outlet manifold in the fuel cell module.

[0006] A second fuel cell module, disclosed in the present description, comprises a fuel cell stack, a fuel gas outlet distributor, an oxidation gas outlet distributor, a gas-liquid separator, and a first water drain pipe. The fuel cell stack consists of several stacked fuel cell cells and comprises a first end face on one side in one stacking direction of the fuel cell cells and a second end face on the other side in the stacking direction. The fuel gas outlet distributor extends within the fuel cell stack in the stacking direction, is configured such that a fuel gas that has flowed through each of the fuel cell cells flows through the fuel gas outlet distributor, and includes a fuel gas outlet opening at the first end face.The oxidation gas outlet manifold extends within the fuel cell stack in the stack direction and is configured so that any oxidation gas flowing through each fuel cell flows through the manifold. It includes an oxidation gas outlet opening at the second end face. The gas-liquid separator separates water from any fuel gas discharged from the fuel gas outlet opening. The first water drain pipe extends from the gas-liquid separator through the first end face, passes through the oxidation gas outlet manifold, and extends to the oxidation gas outlet opening.

[0007] In the fuel cell module, the first water drain pipe, through which water separated in the gas-liquid separator is discharged, runs through the oxidation gas outlet distributor and extends to the oxidation gas outlet opening. This allows the routing path of the first water drain pipe to be shortened, and the fuel cell module can be designed to be smaller.

[0008] In the first fuel cell module, a water drain pipe can be arranged in the oxidation gas outlet manifold, and the water drain pipe can extend from an upstream end section of the oxidation gas outlet manifold to the oxidation gas outlet opening. An outlet of the water drain pipe can be arranged upstream of an outlet of the water drain pipe in the oxidation gas outlet manifold.

[0009] This configuration allows for easy drainage of the water generated in the oxidation gas outlet manifold. Furthermore, it suppresses backflow in the water drain channel.

[0010] In the second fuel cell module, a second water drain pipe can be arranged in the oxidation gas outlet manifold, and this second water drain pipe can extend from an upstream end section of the oxidation gas outlet manifold to the oxidation gas outlet opening. An outlet of the first water drain pipe can be located upstream of an outlet of the second water drain pipe in the oxidation gas outlet manifold.

[0011] This configuration allows for easy drainage of the water generated in the oxidation gas outlet manifold. Furthermore, it suppresses backflow in the first water drain pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The features and advantages as well as the technical and economic significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, here showing Fig. 1 a sectional view of a fuel cell module according to a first embodiment; Fig. 2 the tilted fuel cell module; Fig. 3 a sectional view of a fuel cell module according to a second embodiment; and Fig. 4 a sectional view of a fuel cell module combining the first and second embodiments. DETAILED DESCRIPTION OF EXECUTION FORMS First embodiment

[0013] A fuel cell module 10a according to a first embodiment, which is in Fig. The fuel cell module 10a, shown in Figure 1, is attached to an electrified vehicle or electric vehicle. The fuel cell module 10a comprises a fuel cell stack 20. The fuel cell module 10a supplies electrical energy, generated in the fuel cell stack 20, to a drive motor of the electric vehicle.

[0014] The fuel cell stack 20 comprises several stacked fuel cell cells 22 and end plates 24, 26. The fuel cell cells 22 are stacked such that the stacking direction coincides with the horizontal direction in the electric vehicle. In the stacking direction, both ends of the fuel cell stack 22 are covered by the end plates 24, 26. That is, the fuel cell stack 22 is arranged between the end plates 24, 26 in the stacking direction. In the following description, of the two end faces of the fuel cell stack 20, the end face on the side of the end plate 24 is referred to as the first end face 20a, and the end face on the side of the end plate 26 is referred to as the second end face 20b.

[0015] A fuel gas and an oxidizer gas are supplied to each of the fuel cell cells 22 via a distributor (not shown). In the present embodiment, the fuel gas is hydrogen and the oxidizer gas is air (more precisely, oxygen contained in the air).

[0016] Each of the fuel cell cells 22 generates electricity through the reaction of the fuel gas with the oxidizer gas. As in Fig. As shown in Figure 1, a fuel gas outlet distributor 30 and an oxidation gas outlet distributor 40 are provided within the fuel cell stack 20.

[0017] The fuel gas outlet distributor 30 extends through each of the fuel cell cells 22 within the fuel cell stack 20 in the stack direction. The fuel gas outlet distributor 30 includes a fuel gas outlet opening 30a that penetrates the end plate 24 and is open towards the first end surface 20a. The fuel gas outlet opening 30a is connected to a fuel gas outlet device 90, which is attached to the electric vehicle. The fuel gas that has flowed through each of the fuel cell cells 22 flows through the fuel gas outlet distributor 30. Furthermore, water is produced in each of the fuel cell cells 22 by the reaction between the fuel gas and the oxidizer gas. Each of the fuel cell cells 22 discharges the produced water together with the fuel gas to the fuel gas outlet distributor 30. Therefore, the fuel gas and the produced water flow from the fuel gas outlet distributor 30 to the fuel gas outlet device 90.The fuel gas outlet device 90 comprises a gas-liquid separator 90a. The fuel gas outlet device 90 separates the fuel gas from the generated water via the gas-liquid separator 90a and returns the separated fuel gas to the fuel cell stack 20. Furthermore, the fuel gas outlet device 90 discharges the fuel gas that could not be separated from the generated water, together with the generated water, from the electric vehicle to the outside.

[0018] The oxidation gas outlet distributor 40 extends through each of the fuel cell cells 22 within the fuel cell stack 20 in the stack direction. The oxidation gas outlet distributor 40 includes an oxidation gas outlet opening 40a that penetrates the end plate 26 and is open towards the second end surface 20b. The oxidation gas outlet opening 40a is connected to an oxidation gas outlet device 92, which is attached to the electric vehicle. The oxidation gas that has flowed through each of the fuel cell cells 22 flows through the oxidation gas outlet distributor 40. Furthermore, each of the fuel cell cells 22 discharges the generated water together with the oxidation gas to the oxidation gas outlet distributor 40. Therefore, the oxidation gas and the generated water flow from the oxidation gas outlet distributor 40 to the oxidation gas outlet device 92. The oxidation gas outlet device 92 discharges the oxidation gas together with the generated water from the electric vehicle to the outside.

[0019] A water drain pipe 42 is provided within the oxidation gas outlet distributor 40. The water drain pipe 42 is a thin pipe, thinner than the oxidation gas outlet distributor 40, with both ends open. The water drain pipe 42 extends from the upstream end section (i.e., the first end face 20a) of the oxidation gas outlet distributor 40 to the oxidation gas outlet opening 40a. As the generated water accumulates at the upstream end section of the oxidation gas outlet distributor 40, it is discharged through the water drain pipe 42 to the oxidation gas outlet opening 40a. In this way, the water drain pipe 42 facilitates the discharge of the generated water in the oxidation gas outlet distributor 40.

[0020] A water drain channel 32 is provided within the end plate 26. The water drain channel 32 is thinner than the fuel gas outlet distributor 30 and the oxidation gas outlet distributor 40. The upstream end of the water drain channel 32 is connected to the upstream end section of the fuel gas outlet distributor 30. The downstream end of the water drain channel 32 is connected to the oxidation gas outlet opening 40a. An outlet 32a of the water drain channel 32 is located upstream of an outlet 42a of the water drain pipe 42 in the oxidation gas outlet distributor 40. The water drain channel 32 is equipped with a valve 34. The valve 34 is controlled by a control circuit 36.

[0021] The control circuit 36 ​​determines whether the generated water must be discharged through the water drainage channel 32. For example, if the fuel cell module 10a is as shown in Fig. If the electric vehicle is inclined (as shown in Figure 2) and the second end surface 20b lies below the first end surface 20a due to the inclination of the electric vehicle, etc., the water generated in the fuel gas outlet distributor 30 does not flow easily to the fuel gas outlet opening 30a. When such a situation occurs, where it is difficult to drain the generated water from the fuel gas outlet opening 30a, the control circuit 36 ​​determines that it is necessary to drain the generated water through the water drain channel 32. If it is necessary to drain the generated water through the water drain channel 32, the control circuit 36 ​​determines whether the pressure in the fuel gas outlet distributor 30 is higher than the pressure in the oxidation gas outlet distributor 40. If the pressure in the fuel gas outlet distributor 30 is higher than the pressure in the oxidation gas outlet distributor 40, the control circuit 36 ​​opens the valve 34.Accordingly, the water generated in the fuel gas outlet distributor 30 is discharged through the water drain channel 32 to the oxidation gas outlet 40a. In this way, even when it is difficult to discharge the water generated in the fuel gas outlet distributor 30 directly from the fuel gas outlet 30a, it can be discharged via the water drain channel 32. As described above, the outlet 32a of the water drain channel 32 is located upstream of the outlet 42a of the water drain pipe 42. This prevents the water discharged from the water drain pipe 42 from flowing back into the water drain channel 32. If the pressure in the fuel gas outlet distributor 30 is lower than the pressure in the oxidation gas outlet distributor 40, the control circuit 36 ​​keeps the valve 34 closed and does not discharge the generated water and fuel gas through the water drain channel 32.This prevents the oxidation gas from flowing back from the oxidation gas outlet distributor 40 through the water drain channel 32 to the fuel gas outlet distributor 30.

[0022] In the first embodiment, the control circuit 36 ​​keeps the valve 34 closed when the pressure in the fuel gas outlet distributor 30 is lower than the pressure in the oxidation gas outlet distributor 40. However, in this case, the control circuit 36 ​​can control the supply device for each gas so that the pressure in the fuel gas outlet distributor 30 is higher than the pressure in the oxidation gas outlet distributor 40. For example, the control circuit 36 ​​can increase the pressure in the fuel gas outlet distributor 30 or decrease the pressure in the oxidation gas outlet distributor 40. The control circuit 36 ​​can open the valve 34 after the pressure in the fuel gas outlet distributor 30 has become higher than the pressure in the oxidation gas outlet distributor 40. Even in this configuration, the generated water can be discharged through the water drain channel 32, while the oxidation gas is prevented from flowing back to the fuel gas outlet distributor 30.

[0023] In the first embodiment, the valve 34 is located in the water drain channel 32. However, if the oxidation gas does not flow back from the oxidation gas outlet distributor 40 to the fuel gas outlet distributor 30 (for example, if backflow is prevented by other means) or if backflow is not a problem, the valve 34 does not need to be located in the water drain channel 32. That is, the water drain channel 32 can always be open in this case. Even in this configuration, the generated water can be discharged through the water drain channel 32. Second embodiment

[0024] A fuel cell module 10b according to a second embodiment, which is in Fig. The component shown in Figure 3 is attached to an electrified vehicle or electric vehicle. The fuel cell module 10b comprises the fuel cell stack 20. The fuel cell module 10b supplies the electrical energy generated in the fuel cell stack 20 to a drive motor of the electric vehicle.

[0025] The fuel cell stack 20 comprises several stacked fuel cell cells 22 and the end plates 24, 26. The fuel cell cells 22 are stacked such that the stacking direction coincides with the horizontal direction in the electric vehicle. In the stacking direction, both ends of the fuel cell stack 22 are covered by the end plates 24, 26. That is, the fuel cell stack 22 is arranged between the end plates 24, 26 in the stacking direction. In the following description, of the two end faces of the fuel cell stack 20, the end face on the side of the end plate 24 is referred to as the first end face 20a, and the end face on the side of the end plate 26 is referred to as the second end face 20b.

[0026] A fuel gas and an oxidizer gas are fed to each of the fuel cell cells 22 via a distributor (not shown). In the present embodiment, the fuel gas is hydrogen and the oxidizer gas is air (more precisely, oxygen contained in the air). Each of the fuel cell cells 22 generates electricity through the reaction of the fuel gas with the oxidizer gas. As shown in Fig. As shown in Figure 3, the fuel gas outlet distributor 30 and the oxidation gas outlet distributor 40 are provided within the fuel cell stack 20.

[0027] The fuel gas outlet distributor 30 extends in the stacking direction through each of the fuel cell cells 22 within the fuel cell stack 20. The fuel gas outlet distributor 30 includes the fuel gas outlet opening 30a, which penetrates the end plate 24 and is open towards the first end surface 20a. The gas-liquid separator 90a is located near the first end surface 20a. The fuel gas outlet opening 30a is connected to the gas-liquid separator 90a. The fuel gas that has flowed through each of the fuel cell cells 22 flows through the fuel gas outlet distributor 30. Furthermore, water is produced in each of the fuel cell cells 22 by the reaction between the fuel gas and the oxidation gas. Each of the fuel cell cells 22 discharges the produced water together with the fuel gas to the fuel gas outlet distributor 30. Therefore, the fuel gas and the water produced flow from the fuel gas outlet distributor 30 to the gas-liquid separator 90a.The gas-liquid separator 90a separates the fuel gas from the produced water and feeds the separated fuel gas back to the fuel cell stack 20.

[0028] The oxidation gas outlet distributor 40 extends through each of the fuel cell cells 22 within the fuel cell stack 20 in the stack direction. The oxidation gas outlet distributor 40 includes the oxidation gas outlet opening 40a, which penetrates the end plate 26 and is open towards the second end surface 20b. The oxidation gas outlet opening 40a is connected to the oxidation gas outlet device 92, which is attached to the electric vehicle. The oxidation gas that has flowed through each of the fuel cell cells 22 flows through the oxidation gas outlet distributor 40. Furthermore, each of the fuel cell cells 22 discharges the generated water together with the oxidation gas to the oxidation gas outlet distributor 40. Therefore, the oxidation gas and the generated water flow from the oxidation gas outlet distributor 40 to the oxidation gas outlet device 92. The oxidation gas outlet device 92 discharges the oxidation gas together with the generated water from the electric vehicle to the outside.

[0029] The water drain pipe 42 is located within the oxidation gas outlet distributor 40. The water drain pipe 42 is a thin pipe, thinner than the oxidation gas outlet distributor 40, with both ends open. The water drain pipe 42 extends from the upstream end section (i.e., the side of the first end face 20a) of the oxidation gas outlet distributor 40 to the oxidation gas outlet opening 40a. As the generated water accumulates at the upstream end section of the oxidation gas outlet distributor 40, it is discharged through the water drain pipe 42 to the oxidation gas outlet 40a. In this way, the water drain pipe 42 facilitates the discharge of the generated water in the oxidation gas outlet distributor 40.

[0030] A water drain pipe 46 is connected to the gas-liquid separator 90a. The water drain pipe 46 extends from the gas-liquid separator 90a through the first end face 20a into the oxidation gas outlet distributor 40. The water drain pipe 46 extends from the gas-liquid separator 90a to the oxidation gas outlet opening 40a. An outlet 46a of the water drain pipe 46 is located upstream of the outlet 42a of the water drain pipe 42 in the oxidation gas outlet distributor 40. As described above, the gas-liquid separator 90a separates the fuel gas from the water produced. The gas-liquid separator 90a directs the fuel gas not separated from the produced water and the produced water via the water drain pipe 46 to the oxidation gas outlet opening 40a. The water drain pipe 46 is equipped with a valve 48. The valve 48 is controlled by a control circuit 49.

[0031] The control circuit 49 determines whether it is necessary to drain the generated water via the water drain pipe 46. If it is necessary to drain the generated water via the water drain pipe 46, the control circuit 49 determines whether the pressure in the gas-liquid separator 90a is higher than the pressure in the oxidation gas outlet distributor 40. If the pressure in the gas-liquid separator 90a is higher than the pressure in the oxidation gas outlet distributor 40, the control circuit 49 opens the valve 48. Accordingly, the generated water and the fuel gas from the gas-liquid separator 90a are discharged via the water drain pipe 46 to the oxidation gas outlet opening 40a. The generated water and fuel gas, which are discharged from the water drain pipe 46 to the oxidation gas outlet 40a, are discharged from the electric vehicle to the outside through the oxidation gas outlet device 92, together with the generated water and the oxidation gas in the oxidation gas outlet distributor 40.As described above, the outlet 46a of the water drain pipe 46 is located upstream of the outlet 42a of the water drain pipe 42. This prevents the water discharged from the water drain pipe 42 from flowing back into the water drain pipe 46. If the pressure in the gas-liquid separator 90a is lower than the pressure in the oxidation gas outlet distributor 40, the control circuit 49 keeps the valve 48 closed and does not discharge the generated water and fuel gas through the water drain pipe 46. This prevents the oxidation gas from flowing back from the oxidation gas outlet distributor 40 through the water drain pipe 46 to the gas-liquid separator 90a.

[0032] As described above, in the second embodiment the water drain pipe 46, which carries away the generated water and the fuel gas from the gas-liquid separator 90a, extends through the end plate 24 and through the oxidation gas outlet distributor 40. According to this configuration, the routing path of the water drain pipe 46 can be shorter than if the water drain pipe 46 were arranged outside the fuel cell stack 20, thus allowing the fuel cell module 10b to be designed smaller.

[0033] In the second embodiment, the control circuit 49 keeps the valve 48 closed when the pressure in the gas-liquid separator 90a is lower than the pressure in the oxidation gas outlet distributor 40. However, in this case, the control circuit 49 can control the supply device for each gas so that the pressure in the gas-liquid separator 90a is higher than the pressure in the oxidation gas outlet distributor 40. For example, the pressure in the gas-liquid separator 90a can be increased, or the pressure in the oxidation gas outlet distributor 40 can be decreased. The control circuit 49 can open the valve 48 after the pressure in the gas-liquid separator 90a has become higher than the pressure in the oxidation gas outlet distributor 40. Even in this configuration, the generated water can be discharged through the water drain pipe 46, while the oxidation gas is prevented from flowing back to the gas-liquid separator 90a.

[0034] In the second embodiment, the valve 48 is provided in the water drain pipe 46. However, if the oxidation gas does not flow back from the oxidation gas outlet distributor 40 to the gas-liquid separator 90a (for example, if the backflow is prevented by other means), the valve 48 does not need to be provided in the water drain pipe 46. That is, the water drain pipe 46 can always be open in this case.

[0035] Furthermore, as in Fig. As shown in section 4, the first and second embodiments can be combined.

[0036] Although the embodiments 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 comprises various modifications and variations of the specific embodiments illustrated above by way of example. The technical elements described in this description or in the drawings have technical utility on their own or in various combinations and are not limited to the combinations described in the claims at the time of filing of the application. Furthermore, the technology illustrated by way of example in this description or in the drawings achieves several purposes simultaneously, and the achievement of one of the purposes itself has technical utility. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2007 - 042 538 A

[0002]

Claims

[1] Fuel cell module comprising: a fuel cell stack consisting of several stacked fuel cell cells, wherein the fuel cell stack comprises a first end face on one side in a stacking direction of the fuel cell cells and a second end face on another side in the stacking direction; a fuel gas outlet distributor extending within the fuel cell stack in the stack direction, configured such that a fuel gas that has flowed through each of the fuel cell cells flows through the fuel gas outlet distributor and includes a fuel gas outlet opening at the first end face; an oxidation gas outlet manifold extending within the fuel cell stack in the stack direction, configured such that an oxidation gas that has flowed through each of the fuel cell cells flows through the oxidation gas outlet manifold, and includes an oxidation gas outlet opening at the second end face; and a water drainage channel that connects an upstream end section of the fuel gas outlet distributor and the oxidation gas outlet opening. [2] Fuel cell module according to claim 1, wherein: a water drain pipe is arranged in the oxidation gas outlet distributor, the water drain pipe extending from an upstream end section of the oxidation gas outlet distributor to the oxidation gas outlet opening; and An outlet of the water drainage channel is located upstream of an outlet of the water drainage pipe in the oxidation gas outlet distributor. [3] Fuel cell module comprising: a fuel cell stack consisting of several stacked fuel cell cells, wherein the fuel cell stack comprises a first end face on one side in a stacking direction of the fuel cell cells and a second end face on another side in the stacking direction; a fuel gas outlet distributor extending within the fuel cell stack in the stack direction, configured such that a fuel gas that has flowed through each of the fuel cell cells flows through the fuel gas outlet distributor and includes a fuel gas outlet opening at the first end face; an oxidation gas outlet distributor extending within the fuel cell stack in the stack direction, configured such that an oxidation gas that has flowed through each of the fuel cell cells flows through the oxidation gas outlet distributor, and includes an oxidation gas outlet opening at the second end face; a gas-liquid separator that separates water from fuel gas discharged from the fuel gas outlet opening; and a first water drain pipe extending from the gas-liquid separator through the first end face, passing through the oxidation gas outlet distributor and extending to the oxidation gas outlet opening. Fuel cell module according to claim 3, wherein: a second water drain pipe is arranged in the oxidation gas outlet distributor, the second water drain pipe extending from an upstream end section of the oxidation gas outlet distributor to the oxidation gas outlet opening; and An outlet of the first water drain pipe is located upstream of an outlet of the second water drain pipe in the oxidation gas outlet distributor.

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