Fuel cell module

Abstract

A fuel cell module comprises a fuel cell stack consisting of a plurality of stacked fuel cell cells, a fuel gas outlet manifold extending within the fuel cell stack in a stacking direction through which a fuel gas flows that has passed through each of the fuel cell cells, an oxidation gas outlet manifold extending within the fuel cell stack in the stacking direction through which an oxidation gas flows that has passed through each of the fuel cell cells, an outlet flow channel that discharges the oxidation gas from the oxidation gas outlet manifold, a pressure control valve provided in the outlet flow channel, the pressure control valve being configured to reduce the pressure in the outlet flow channel downstream of the pressure control valve to a pressure lower than the pressure in the oxidation gas outlet manifold, and a water drain flow channel.

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 2020-155212A comprises a fuel cell stack formed by stacking a plurality of fuel cell cells. The fuel cell stack generates electricity through the reaction of a fuel gas with an oxidizer gas. A fuel gas outlet distributor is provided within the fuel cell stack, which discharges the fuel gas passed through the fuel cell cells. Furthermore, an oxidizer gas outlet distributor is provided within the fuel cell stack, which discharges the oxidizer gas passed through the fuel cell cells. SUMMARY OF THE INVENTION

[0003] In the fuel cell stack, water is produced through the reaction between the fuel gas and the oxidation gas (hereinafter referred to as "produced water"). The produced water is discharged from the fuel cell stack to the outside via the fuel gas outlet distributor and the oxidation gas outlet distributor.

[0004] The fuel cell module can be provided with a water drain channel that directs the generated water from the fuel gas outlet manifold to the oxidation gas outlet manifold. If the water drain channel is provided, the discharge paths of the generated water between the fuel gas outlet manifold and the oxidation gas outlet manifold can be unified. However, if the water drain channel is provided in this way, the generated water and the oxidation gas can flow backwards in the water drain channel. The present invention proposes a technique that suppresses this backflow in a water drain channel. First aspect

[0005] In a fuel cell module disclosed in the present description, a fuel cell stack consisting of several (a plurality of) stacked fuel cell cells comprises a fuel gas outlet distributor extending in a stacking direction within the fuel cell stack and through which a fuel gas flows that has flowed through each of the fuel cell cells, an oxidation gas outlet distributor extending in the stacking direction within the fuel cell stack and through which an oxidation gas flows that has flowed through each of the fuel cell cells, an outlet flow channel that discharges the oxidation gas from the oxidation gas outlet distributor, and a pressure control valve arranged in the outlet flow channel, wherein the pressure control valve is configured to reduce a pressure in the outlet flow channel downstream of the pressure control valve to a pressurewhich is lower than the pressure in the oxidation gas outlet distributor, and a water drain flow channel that discharges water generated within the fuel cell cells from the fuel gas outlet distributor to the outlet flow channel downstream of the pressure regulating valve.

[0006] In the fuel cell module described above, the water drain channel directs the generated water from the fuel gas outlet manifold into the outlet channel downstream of the pressure regulating valve. The pressure in the outlet channel downstream of the pressure regulating valve is regulated by the pressure regulating valve so that it is lower than the pressure in the oxidation gas outlet manifold. This prevents backflow in the water drain channel.

[0007] Following the first aspect described above, further configurations of the fuel cell system disclosed in this description will be described below. Second aspect

[0008] The fuel cell module according to the first aspect further includes a gas-liquid separator, wherein the fuel cell stack is provided with a first end face on one side in the stacking direction and a second end face on another side in the stacking direction, the fuel gas outlet distributor has a fuel gas outlet opening at the first end face, the oxidation gas outlet distributor has an oxidation gas outlet opening at the second end face, the oxidation gas outlet opening being connected to the outlet flow channel, the gas-liquid separator separates the water from the fuel gas expelled from the fuel gas outlet opening, and the water discharge flow channel is configured to discharge the water separated in the gas-liquid separator into the outlet flow channel downstream of the pressure regulating valve, and extends from the gas-liquid separator through the first end face,through the oxidation gas outlet distributor and extends to the outlet flow channel. Third aspect

[0009] In the fuel cell module according to the first or second aspect, the fuel cell stack is provided with 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 opening at the first end face, the oxidation gas outlet manifold has an oxidation gas outlet opening at the second end face, the oxidation gas outlet opening being connected to the outlet flow channel, and the water drain flow channel extends from an upstream end section of the fuel gas outlet manifold to the outlet flow channel downstream of the pressure regulating valve. Fourth aspect

[0010] In the fuel cell module according to one of the first to third aspects, a water drain pipe extending along the stacking direction is provided within the oxidation gas outlet distributor.

[0011] According to the second aspect, the water drain channel, which carries away the water separated by the gas-liquid separator, extends through the oxidation gas outlet distributor to the outlet flow channel. This allows the length of the water drain channel to be shortened and the fuel cell module to be made smaller.

[0012] According to the third aspect, the water accumulated at the upstream end of the fuel gas outlet manifold is drained through the water drain channel to the outlet channel downstream of the pressure regulating valve. Therefore, within the fuel gas outlet manifold, the drainage of water through the water drain channel is promoted.

[0013] According to the fourth aspect, the water generated in the oxidation gas outlet distributor can be easily drained away. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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, showing: Fig. 1 a schematic representation of a fuel cell module according to a first embodiment; Fig. 2 a schematic representation of a fuel cell module according to a second embodiment; Fig. 3 a schematic representation of a fuel cell module according to a third embodiment; Fig. 4 a schematic representation of a fuel cell module according to a fourth embodiment; and Fig. 5 a schematic representation of a fuel cell module according to a fifth embodiment. DETAILED DESCRIPTION OF THE EXECUTION FORMS First embodiment

[0015] A fuel cell module 100 according to a first embodiment, which is in Fig. The device shown in Figure 1 is attached to a device powered by a fuel cell (for example, a fuel cell electric vehicle). The fuel cell module 100 comprises a fuel cell stack 10. The fuel cell module 100 supplies electrical energy generated in the fuel cell stack 10 to a motor, etc.

[0016] The fuel cell stack 10 comprises several stacked fuel cell cells 12 and end plates 14, 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 arranged sandwich-like between the end plates 14, 16 in the stacking direction. In the following description, the end surface on the side of the end plate 14 is referred to as the first end surface 10a, and the end surface on the side of the end plate 16 is referred to as the second end surface 10b in the fuel cell stack 10.

[0017] An oxidizer gas (e.g., air) is supplied to each of the fuel cell cells 12 from a distributor (not shown), and a fuel gas (e.g., hydrogen) is supplied to each of the fuel cell cells 12 from a distributor (not shown). Each of the fuel cell cells 12 generates electricity through the reaction of the fuel gas with the oxidizer gas. As a result of the reaction, water (hereinafter referred to as "produced water") is produced in each of the fuel cell cells 12. As in Fig. As shown in Figure 1, a fuel gas outlet distributor 20 and an oxidation gas outlet distributor 22 are provided within the fuel cell stack 10.

[0018] The fuel gas outlet distributor 20 extends in the stacking direction through each of the fuel cell cells 12 and the end plate 14 within the fuel cell stack 10. The fuel gas outlet distributor 20 includes a fuel gas outlet opening 20a. The fuel gas outlet opening 20a opens towards the second first end surface 10a. The fuel gas, which has flowed through the interior of each fuel cell 12, flows through the fuel gas outlet distributor 20. The fuel cell cells 12 discharge the generated water together with the fuel gas to the fuel gas outlet distributor 20. The generated water and the fuel gas flow through the fuel gas outlet distributor 20 and are discharged to the outside of the fuel cell stack 10 via the fuel gas outlet opening 20a.

[0019] The oxidation gas outlet distributor 22 extends through each of the fuel cell cells 12 and the end plate 16 within the fuel cell stack 10 in the stack direction. The oxidation gas outlet distributor 22 includes an oxidation gas outlet opening 22a. The oxidation gas outlet opening 22a opens to the second end surface 10b. The oxidation gas that has flowed through each of the fuel cell cells 12 flows through the oxidation gas outlet distributor 22. The fuel cell cells 12 discharge the generated water together with the oxidation gas to the oxidation gas outlet distributor 22. The oxidation gas and the generated water flow through the oxidation gas outlet distributor 22 towards the oxidation gas outlet opening 22a.

[0020] A water drain pipe 30 is provided within the oxidation gas outlet distributor 22. The water drain pipe 30 is a pipe that is thinner than the oxidation gas outlet distributor 22 and whose two ends are exposed. The water drain pipe 30 extends from the upstream end section (i.e., the side of the first end face 10a) of the oxidation gas outlet distributor 22 to the oxidation gas outlet opening 22a. That is, the water drain pipe 30 extends along the stacking direction of the fuel cell cells 12. When the generated water accumulates at the upstream end section of the oxidation gas outlet distributor 22, it is discharged through the water drain pipe 30 to the oxidation gas outlet opening 22a. Therefore, the discharge of the generated water through the water drain pipe 30 is facilitated within the oxidation gas outlet distributor 22.

[0021] The fuel cell module 100 includes an outlet flow channel 24. The upstream end of the outlet flow channel 24 is connected to the oxidation gas outlet opening 22a. The oxidation gas and the generated water, which flow through the oxidation gas outlet distributor 22, are discharged from the fuel cell stack 10 to the outside via the outlet flow channel 24. The outlet flow channel 24 is equipped with a pressure regulating valve 26. The fuel cell module 100 includes a control device 40. The control device 40 controls the pressure regulating valve 26. The control device 40 controls the pressure regulating valve 26 such that the pressure in the outlet flow channel 24 downstream of the pressure regulating valve 26 is lower than the pressure in the oxidation gas outlet distributor 22.

[0022] The fuel cell module 100 includes a water drain flow channel 32. The water drain flow channel 32 is a flow channel that is narrower than the fuel gas outlet distributor 20 and the oxidation gas outlet distributor 22. The upstream end of the water drain flow channel 32 is connected to the upstream end section of the oxidation gas outlet distributor 22 (i.e., the side of the second end face 10b). The water drain flow channel 32 penetrates the end plate 16 and extends to the outlet flow channel 24. The downstream end of the water drain flow channel 32 is connected to the outlet flow channel 24 downstream of the pressure regulating valve 26. The water drain flow channel 32 is equipped with a valve 34. The valve 34 opens and closes the passage of the water drain flow channel 32.When valve 34 is in an open state and the generated water accumulates at the upstream end section of the fuel gas outlet distributor 20, the generated water is discharged through the water drain flow channel 32 to the outlet flow channel 24. The water drain flow channel 32 facilitates the discharge of the generated water from the fuel gas outlet distributor 20.

[0023] As described above, during operation of the fuel cell module 100, the fuel gas and the water produced are discharged from the fuel gas outlet distributor 20 through the fuel gas outlet opening 20a from the fuel cell stack 10 to the outside, and the oxidation gas and the water produced are discharged from the oxidation gas outlet distributor 22 through the outlet flow channel 24 from the fuel cell stack 10 to the outside. During operation of the fuel cell module 100, the valve 34 is controlled to remain in the open position. Therefore, if the water produced accumulates in the fuel gas outlet distributor 20, it is discharged through the water drain flow channel 32 to the outlet flow channel 24.Since at this point the pressure in the outlet flow channel 24 downstream of the pressure regulating valve 26 is regulated by the pressure regulating valve 26 so that it is lower than the pressure in the oxidation gas outlet distributor 22, the pressure at the outlet of the water discharge flow channel 32 is low. Therefore, the oxidation gas and the generated water are prevented from flowing back from the outlet flow channel 24 into the water discharge flow channel 32. Consequently, the water generated in the fuel gas outlet distributor 20 is appropriately discharged into the outlet flow channel 24. Second embodiment

[0024] Fig. Figure 2 shows a fuel cell module 102 according to a second embodiment. Fig. 2 are parts that are the same as those in Fig. The fuel cell module 102 of the second embodiment is designated with the same reference numerals. It differs from the fuel cell module of the first embodiment in that it does not contain a water drain flow channel 32 and instead includes a water drain pipe 44, a gas-liquid separator 42, and a water drain flow channel 36. Otherwise, the fuel cell module 102 of the second embodiment is identical to the fuel cell module of the first embodiment.

[0025] 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 opening 20a. The generated water and the fuel gas discharged from each of the fuel cell cells 12 flow through the fuel gas outlet distributor 20 and are discharged to the gas-liquid separator 42 via the fuel gas outlet opening 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 fed back to the fuel cell stack 10 via a fuel gas supply path (not shown).

[0026] The water drain pipe 44 is located within the fuel gas outlet distributor 20. The water drain pipe 44 is a conduit that is thinner than the fuel gas outlet distributor 20 and whose two ends are exposed. The water drain pipe 44 extends from the upstream end section (i.e., the side of the second end face 10b) of the fuel gas outlet distributor 20 to the fuel gas outlet opening 20a. That is, the water drain pipe 44 extends along the stacking direction of the fuel cell cells 12. When the generated water accumulates at the upstream end section of the fuel gas outlet distributor 20, it flows through the water drain pipe 44 and is discharged via the fuel gas outlet opening 20a to the gas-liquid separator 42. Within the fuel gas outlet distributor 20, the discharge of the generated water is facilitated by the water drain pipe 44.

[0027] The fuel cell module 102 includes the water drain flow channel 36, which consists of a thin tube. The water drain flow channel 36 is a flow channel that is narrower than the fuel gas outlet distributor 20 and the oxidation gas outlet distributor 22. The upstream end of the water drain flow channel 36 is connected to the gas-liquid separator 42. The water drain flow channel 36 extends from the gas-liquid separator 42 through the first end face 10a into the oxidation gas outlet distributor 22. The water drain flow channel 36 extends through the interior of the oxidation gas outlet distributor 22 to the oxidation gas outlet opening 22a. The water drain flow channel 36 exits the outlet flow channel 24 to the outside. The downstream end of the water drain flow channel 36 is connected to the outlet flow channel 24 downstream of the pressure regulating valve 26. The water drain flow channel 36 is equipped with a valve 38.Valve 38 opens and closes the passage of the water drain flow channel 36. When valve 38 is open, the water separated from the fuel gas by the gas-liquid separator 42 is discharged via the water drain flow channel 36 into the outlet flow channel 24.

[0028] During operation of the fuel cell module 102 of the second embodiment, the oxidation gas and the water produced are discharged from the oxidation gas outlet distributor 22 through the outlet flow channel 24 from the fuel cell stack 10 to the outside, similar to the first embodiment. During operation of the fuel cell module 102, the fuel gas and the water produced are discharged from the fuel gas outlet distributor 20 into the gas-liquid separator 42, as described above. Furthermore, during operation of the fuel cell module 102, the valve 38 is controlled so that it is in the open state. This allows the water produced in the gas-liquid separator 42 to be discharged via the water drain flow channel 36 to the outlet flow channel 24. This means that the water drain flow channel 36 directs the water generated in the fuel cell cells 12 from the fuel gas outlet distributor 20 to the outlet flow channel 24 downstream of the pressure regulating valve 26.Since the pressure in the outlet flow channel 24 downstream of the pressure regulating valve 26 is regulated by the pressure regulating valve 26 so that it is lower than the pressure in the oxidation gas outlet distributor 22, the pressure at the outlet of the water drain flow channel 36 is low. Therefore, the oxidation gas and the generated water are prevented from flowing back from the outlet flow channel 24 into the water drain flow channel 36.

[0029] In the second embodiment, as described above, the water drain flow channel 36 is arranged to run through the oxidation gas outlet distributor 22. According to this configuration, the flow channel length of the water drain flow channel 36 can be shorter than if the water drain flow channel 36 were located outside the fuel cell stack 10, and the fuel cell module 102 can be made smaller. Third embodiment

[0030] A fuel cell module 103 according to a third embodiment, which is in Fig. The fuel cell module 103 of the third embodiment, as shown in Figure 3, differs from the fuel cell module of the second embodiment with respect to the pressure regulating valve. Furthermore, the fuel cell module 103 of the third embodiment differs from the fuel cell module of the second embodiment with respect to the arrangement of the downstream section of the water drain flow channel 36. The remaining configurations of the fuel cell module 103 of the third embodiment correspond to those of the fuel cell module of the second embodiment.

[0031] In the third embodiment, the fuel cell module 103 includes a pressure control valve 50. The pressure control valve 50 is a throttle valve provided with a valve body 52. ​​The pressure control valve 50 is housed in a casing 54. The downstream section of the water drain flow channel 36 extends through the casing 54 and reaches the outlet flow channel 24. In this third embodiment as well, the downstream end of the water drain flow channel 36 is connected to the outlet flow channel 24 downstream of the pressure control valve. Therefore, the generated water can be discharged through the water drain flow channel 36, while backflow in the water drain flow channel 36 is prevented. Fourth embodiment

[0032] In the third embodiment described above, the downstream section of the water drain flow channel 36 runs through the housing 54 and extends to the outlet flow channel 24. In contrast, in a fuel cell module 104 of a fourth embodiment, as described in Fig. Figure 4 shows the water drain flow channel 36 from the gas-liquid separator 42 through the oxidation gas outlet distributor 22 and the valve body 52 to the outlet flow channel 24. In the fourth embodiment as well, the downstream end of the water drain flow channel 36 is connected to the outlet flow channel 24 downstream of the pressure regulating valve. Therefore, the generated water can be discharged through the water drain flow channel 36, while backflow in the water drain flow channel 36 is prevented. Fifth embodiment

[0033] In the configuration of a fuel cell module 105 according to a fifth embodiment, which is described in Fig. As shown in Figure 5, the first and second embodiments are combined. In this case, the water drain pipe 44 does not need to be provided.

[0034] In the first to fifth embodiments, the fuel gas outlet opening 20a is open towards the first end surface 10a. However, the fuel gas outlet opening 20a can also be open towards the second end surface 10b. Furthermore, in the first and second embodiments, the oxidation gas outlet opening 22a is open towards the second end surface 10b. However, the oxidation gas outlet opening 22a can also be open towards the first end surface 10a.

[0035] In the first to fifth embodiments, the water drain pipe 30 is provided within the oxidation gas outlet distributor 22. However, the water drain pipe 30 does not necessarily have to be provided within the oxidation gas outlet distributor 22.

[0036] In the second to fourth embodiments, the water drain pipe 44 is provided inside the fuel gas outlet distributor 20. However, the water drain pipe 44 does not necessarily have to be provided inside the fuel gas outlet distributor 20.

[0037] In the first and fifth embodiments, the water drain flow channel 32 is equipped with the valve 34. However, the water drain flow channel 32 need not be equipped with the valve 34. In this case, the water drain flow channel 32 can always be open.

[0038] In the second to fifth embodiments, the water drain flow channel 36 is provided with the valve 38. However, the water drain flow channel 36 need not be provided with the valve 38. In this case, the water drain flow channel 36 can always be open.

[0039] 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 examples illustrated above. The technical elements described in this description or in the drawings have technical utility, either individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology illustrated by way of example in this description or in the drawings achieves several objectives simultaneously, and the achievement of any one of the objectives has technical utility in itself. 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 2020 - 155 212 A

[0002]

Claims

[1] Fuel cell module comprising: a fuel cell stack consisting of a large number of stacked fuel cell cells; a fuel gas outlet distributor that extends in a stacking direction within the fuel cell stack and through which a fuel gas flows that has flowed through each of the fuel cell cells; an oxidation gas outlet distributor extending in the stacking direction within the fuel cell stack, through which an oxidation gas flows that has flowed through each of the fuel cell cells; an outlet flow channel that releases the oxidation gas from the oxidation gas outlet distributor; a pressure regulating valve arranged in the outlet flow channel, wherein the pressure regulating valve is configured to reduce the pressure in the outlet flow channel downstream of the pressure regulating valve to a pressure lower than the pressure in the oxidation gas outlet manifold; and a water drain flow channel that discharges water generated within the fuel cell cells from the fuel gas outlet distributor to the outlet flow channel downstream of the pressure regulating valve. [2] Fuel cell module according to claim 1, further comprising a gas-liquid separator, wherein: the fuel cell stack is provided with a first end surface on one side in the stacking direction and a second end surface on the other side in the stacking direction; the fuel gas outlet distributor includes a fuel gas outlet opening at the first end face; the oxidation gas outlet distributor comprises an oxidation gas outlet opening at the second end face, wherein the oxidation gas outlet opening is connected to the outlet flow channel; The gas-liquid separator separates the water from the fuel gas expelled from the fuel gas outlet opening; and The water discharge flow channel is configured to discharge the water separated in the gas-liquid separator into the outlet flow channel downstream of the pressure regulating valve, and extends from the gas-liquid separator through the first end face, through the oxidation gas outlet distributor and to the outlet flow channel. [3] Fuel cell module according to claim 1, wherein the fuel cell stack is provided with a first end surface on one side in the stacking direction and a second end surface on the other side in the stacking direction; the fuel gas outlet distributor includes a fuel gas outlet opening at the first end face; the oxidation gas outlet distributor comprises an oxidation gas outlet opening at the second end face, the oxidation gas outlet opening being connected to the outlet flow channel; and The water drain flow channel extends from an upstream end section of the fuel gas outlet distributor to the outlet flow channel downstream of the pressure regulating valve. [4] Fuel cell module according to one of claims 1 to 3, wherein a water drain pipe extending along the stacking direction is provided within the oxidation gas outlet distributor.

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