Fuel cell stack

Abstract

The present invention provides a fuel cell stack (1), in which the fuel cell stack (1) comprises at least: a fuel cell stack body (2) having a plurality of unit fuel cells, in which each unit fuel cell comprises bipolar plates and membrane electrode assemblies alternately stacked in a stacking direction; a first terminal plate and a second terminal plate clamping the fuel cell stack (2), the first terminal plate and the second terminal plate being adapted to collect electrical energy generated by the fuel cell stack (2); a first insulating plate (14) and a second insulating plate clamping the terminal plate, wherein the insulating plates (14) are adapted to electrically insulate the terminal plate; and first and second end plates (4) clamping the insulating plates (14), wherein the at least one first sealing element (18a, 18b) is arranged between the at least one insulating plate (14) and the adjacent end plate (4).

Description

Technical Field

[0001] The invention relates to a fuel cell stack. Background Art

[0002] Generally, a fuel cell stack includes: a stack body including a plurality of membrane electrode assemblies (MEAs) separated by so-called bipolar plates (BPPs); a pair of terminal plates for collecting the current generated by the stack body; and a pair of end plates clamping the terminal plates. In order to insulate each terminal plate from the adjacent end plates, an insulating plate is provided between each terminal plate and the adjacent end plates.

[0003] The bipolar plate itself usually includes at least two conductive metal plates, so-called flow field plates, which are stacked on each other, and the flow field plate has a flow field for reactants on one side and a flow field for cooling fluid on the other side. Therefore, the flow fields of the cooling fluid face each other, wherein the flow field of the reactant fluid faces the MEA. Each bipolar plate and / or membrane electrode assembly includes fuel, oxidant and coolant inlet manifolds, and fuel, oxidant and coolant outlet manifolds. In the assembled stack, each manifold forms a tubular channel that extends through the entire fuel cell stack body and transports the corresponding fluid into the fuel cell stack and outputs it from the fuel cell stack. The flow field of each plate forms an active area for generating electrical energy, wherein the active area is arranged between the inlet manifold and the outlet manifold of each unit fuel cell.

[0004] In order to provide touch protection and / or protection from environmental influences such as water and / or dust, the fuel cell stack is encapsulated in a housing, which includes a bottom plate, a top plate and side walls, wherein sealing elements can be arranged between different elements of the housing to achieve a sealed environment of the fuel cell stack in the housing, thereby ensuring safe and stable operation of the fuel cell stack. Typically, this is ensured by limiting narrow tolerances of any position and / or seat of the sealing element used.

[0005] However, since necessary precision is required when manufacturing the fuel cell stack components in order to ensure the airtightness of the fuel cell stack and the number of components included in the fuel cell stack is large, the manufacturing and assembling costs of the fuel cell stack are high and the workload is large. Summary of the invention

[0006] It is therefore an object of the present invention to provide a fuel cell stack which has improved sealing and which can be assembled in a simple and efficient manner.

[0007] This object is achieved by a fuel cell stack according to claim 1 .

[0008] Hereinafter, a fuel cell stack is provided, which includes a fuel cell stack body having a plurality of unit fuel cells. Each unit fuel cell includes a bipolar plate and a membrane electrode assembly, which are alternately stacked in a stacking direction, wherein each bipolar plate and / or membrane electrode assembly may include at least a fuel, oxidant and coolant inlet manifold, and at least a fuel, oxidant and coolant outlet manifold. The manifold may form a corresponding tubular channel extending through the fuel cell stack body for delivering a corresponding fluid into and out of the fuel cell stack, wherein each unit fuel cell has an active area for generating electrical energy, wherein the active area is arranged between the inlet manifold and the outlet manifold of each unit fuel cell.

[0009] The fuel cell stack also includes a first terminal plate and a second terminal plate that clamp the fuel cell stack body, wherein the first terminal plate and the second terminal plate are suitable for collecting electrical energy generated by the fuel cell stack body. In addition, the fuel cell stack includes a first end plate and a second end plate that clamp the fuel cell stack body, wherein at least one end plate may include at least one inlet opening and at least one outlet opening, wherein at least one inlet opening is aligned with one or more inlet channels, and at least one outlet opening is aligned with one or more outlet channels.

[0010] In addition, the fuel cell stack includes a first insulating plate arranged between the first end plate and the first terminal plate, and a second insulating plate arranged between the second end plate and the second terminal plate, wherein the insulating plate is suitable for electrically insulating the terminal plate from the end plate. At least one insulating plate may include at least fuel, oxidant and coolant inlet pipes, and at least fuel, oxidant and coolant outlet pipes, which are suitable for connecting the channel fluid to at least one inlet opening and at least one outlet opening. Preferably, the inlet pipe and the outlet pipe may extend into at least one inlet opening and at least one outlet opening, respectively. For example, each pipe may include a protrusion extending into the opening of at least one end plate. In addition, the pipe may also be suitable for connecting to corresponding supply lines of fuel, oxidant and coolant.

[0011] In order to provide a fuel cell stack that has sufficient external sealing and can be assembled in a simple and effective manner, at least one first sealing element is arranged between at least one insulating plate and an adjacent end plate. Preferably, the at least one first sealing element is arranged to prevent fluid from entering the space between the at least one insulating plate and the adjacent end plate from the outside of the fuel cell stack. Advantageously, the at least one first sealing element can be arranged on the surface of the at least one end plate facing the relevant insulating plate, so that a seal can be easily formed by compressing the at least one sealing element in the stacking direction. Since the fuel cell stack is usually compressed in the stacking direction during assembly and in the assembled state, it is not necessary to accurately position the component where the at least one first sealing element is located to ensure sufficient sealing.

[0012] According to another embodiment, at least one end plate includes at least one inlet opening and / or at least one outlet opening for supplying reactants and / or coolants to the fuel cell body and / or outputting reactants and / or coolants from the fuel cell body, wherein at least one first sealing element extends around the periphery of at least one inlet and / or at least one outlet. More particularly, at least one first sealing element may extend around the entire periphery of at least one opening. In addition, at least one first sealing element may surround at least one opening on a surface whose surface normal is parallel to the stacking direction. This allows the fuel cell stack to be effectively sealed to prevent water, dust and / or other fluids and / or particles that may enter the fuel cell stack from the outside.

[0013] Preferably, at least one insulating plate comprises fuel, oxidant and coolant inlet ducts and fuel, oxidant and coolant outlet ducts, wherein the inlet ducts extend into one inlet opening and / or the outlet ducts extend into one outlet opening, and / or wherein at least one end plate comprises an opening for each inlet duct and / or outlet duct of the insulating plate, wherein the inlet ducts and the outlet ducts extend into respective openings, and wherein each opening is surrounded by a first sealing element. Thus, each opening in the end plate is protected by a sealing element.

[0014] In addition, the fuel cell stack may further include an outer shell, wherein the outer shell includes at least a bottom plate and a stack cover configured to cover the sides of the fuel cell stack. The stack cover may be formed by a plurality of side walls forming a hollow box. In addition, the outer shell may further include a top plate. For example, one of the end plates may be used as a top plate. This reduces the number of components and the overall weight of the fuel cell stack. Alternatively, the stack cover also includes a top wall.

[0015] Preferably, at least one second sealing element is arranged between the housing and at least one end plate. For example, at least one second sealing element may be arranged between the stack cover and one of the end plates. This ensures the tightness of the housing and prevents water, dust and / or other particles and / or fluids from entering the fuel cell stack. Alternatively or additionally, at least one second sealing element may extend around the periphery of at least one end plate.

[0016] According to another embodiment, one of the end plates is also configured as a bottom plate of the housing. This allows the bottom plate of the housing to be omitted, so that the entire fuel cell stack has a lighter weight and fewer components, which makes the assembly process simpler and the finished fuel cell stack lighter and saves costs. Advantageously, the second end plate can be further configured as a top plate of the housing. This reduces the number of components, thereby further reducing the weight of the fuel cell stack.

[0017] Preferably, at least one end plate is provided with at least one flange, wherein the flange extends around the periphery of the end plate. For example, the flange may provide a fastening interface for the housing for fastening the housing to the end plate. The fastening interface may be a threaded hole in the flange, such as a threaded through hole or a threaded blind hole or a through hole through which a fastening element may pass.

[0018] According to another embodiment, at least one first sealing element is arranged on the surface of at least one end plate facing the associated insulating plate and / or on the surface of at least one insulating plate facing the end plate. Preferably, at least one first sealing element and / or the second sealing element is fixed to at least one end plate or at least one insulating plate. By fixing at least one first sealing element and / or the second sealing element to at least one end plate or at least one insulating plate, the correct positioning of at least one first sealing element and / or the second sealing element can be ensured during the assembly process of the fuel cell stack, thereby improving the sealing of the stack. Preferably, at least one first sealing element and / or the second sealing element is arranged in the groove by bonding or injection molding. For example, at least one sealing element can be a gasket or an O-ring.

[0019] Furthermore, at least one of the first sealing element and / or the second sealing element may be an elastic element compressed in the stacking direction. This has the advantage that the tightness of the fuel cell stack can be ensured only by gravity and / or compression of the fuel cell stack. For example, at least one of the first sealing elements may be compressed by weight and / or by at least one compression element, which is configured to provide additional compression to the fuel cell stack. The compression element may be a compression band wrapped around the fuel cell stack.

[0020] According to another embodiment, the fuel cell stack comprises at least one clamping element, which is configured to apply additional force to at least one insulating plate so that at least one first sealing element is further compressed in the stacking direction. Preferably, the clamping element is fixed to at least one end plate by at least one fastening element. For example, the fastening element can be a screw or a bolt. The clamping element can be arranged so that at least a portion of the edge of the insulating plate is clamped. This ensures that the seal between the insulating plate and the end plate is maintained even if the compression of the fuel cell stack becomes loose (for example due to wear and / or breakage).

[0021] Further preferred embodiments are defined in the dependent claims as well as in the description and drawings. Hence, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, preferred embodiments of the present invention are described in conjunction with the accompanying drawings, wherein the accompanying drawings are only exemplary and are not intended to limit the scope of protection. The scope of protection is limited only by the attached claims.

[0023] The accompanying drawings show:

[0024] Figure 1 : A partial perspective exploded view of a fuel cell stack according to a first embodiment,

[0025] Figure 2 : Figure 1 A side view of the assembled fuel cell stack.

[0026] Figure 3 : Figure 2 Details in III,

[0027] Figure 4 : A perspective view of a fuel cell stack according to a first embodiment,

[0028] Figure 5 : A partial perspective view of a fuel cell stack according to a second embodiment, and

[0029] Figure 6 : Figure 5 A side view of the assembled fuel cell stack. DETAILED DESCRIPTION

[0030] In the following, elements with the same or similar functions are denoted by the same reference numerals.

[0031] Figures 1 to 3 A fuel cell stack 1 is shown, which includes a fuel cell stack body 2 having a plurality of unit fuel cells ( Figure 2 , Figure 3 ) and end plate 4. Each unit fuel cell includes a bipolar plate and a membrane electrode assembly, which are alternately stacked in the stacking direction so that two bipolar plates sandwich the multilayer membrane electrode assembly. Each bipolar plate and / or membrane electrode assembly includes three inlet manifolds (not shown), namely a fuel inlet manifold, an oxidant inlet manifold and a coolant inlet manifold, and three outlet manifolds (not shown), namely a fuel outlet manifold, an oxidant outlet manifold and a coolant outlet manifold, wherein the manifolds form corresponding tubular channels extending through the fuel cell stack 1, and the tubular channels are used to supply corresponding fluids to the fuel cell stack 1 and discharge corresponding fluids from the fuel cell stack 1. Each unit fuel cell has an active area for generating electrical energy, wherein the active area is arranged between the inlet manifold and the outlet manifold of each unit fuel cell.

[0032] In order to collect voltage and output voltage, first and second terminal plates 3 are provided, which clamp the fuel cell stack body 2 at the active area. The first and second terminal plates 3 are suitable for collecting the electrical energy generated by the fuel cell stack 1, wherein each terminal plate 3 also includes a power output terminal 6 that can be connected to an external connector.

[0033] In addition, the fuel cell stack 1 is sandwiched by the first end plate 4 and the second end plate 8 ( Figure 2 ), wherein the first end plate 4 includes an inlet opening 10 and an outlet opening 12. The inlet opening 10 is aligned with the inlet channel, and the outlet opening 12 is aligned with the outlet channel. Figures 1 to 3 In the first embodiment shown, the second end plate 8 is configured to close the tubular channels formed by the inlet manifold and the outlet manifold, thereby forming a dead-end fuel cell. However, outlet openings may also be provided on the second end plate 8. Alternatively, the end plate 4 may include an inlet opening for each inlet channel and an outlet opening for each outlet channel.

[0034] In order to insulate the fuel cell stack 2 from the end plate 4, a first insulating plate 14 is arranged between the end plate 4 and the first terminal plate 3. In addition, a second insulating plate 32 ( Figure 2 ). The insulating plates 14, 32 are each adapted to electrically insulate the terminal plate 3 from the end plates 4, 8. In addition, the first insulating plate 14 comprises a fuel inlet conduit 15a, an oxidant inlet conduit 15b and a coolant inlet conduit 15c and a fuel outlet conduit 17a, an oxidant outlet conduit 17b and a coolant outlet conduit 17c, which are adapted to fluidly connect the channel with the inlet opening 10 and the outlet opening 12. Each of the inlet conduit 15 and the outlet conduit 17 comprises a tubular protrusion 16 extending into the corresponding inlet opening 10 or outlet opening 12.

[0035] To seal the fuel cell stack 1 from the outside, a first sealing element 18a and a second sealing element 18b are arranged between the first insulating plate 14 and the end plate 4. The first sealing element 18a surrounds the inlet opening 10 of the end plate 4, while the second sealing element 18b surrounds the outlet opening 12 of the end plate.

[0036] from Figure 3 It can be seen that the arrangement of the sealing elements 18a, 18b can prevent fluid from entering the space between the insulating plate 14 and the adjacent end plate 4 from the outside of the fuel cell stack. In addition, the sealing elements 18a, 18b are arranged on the surface of the end plate 4 facing the insulating plate 14. The advantage of this is that it is easy to form a tight seal by compressing the sealing elements 18a, 18b in the stacking direction. Since the fuel cell stack 1 is usually compressed in the stacking direction during assembly and in the assembled state, it is not necessary to accurately position the insulating plate 14 and the end plate 4 to ensure sufficient sealing. In the case where the end plate includes an opening for each inlet pipe 15 and each outlet pipe 17, each opening can be surrounded by a sealing element.

[0037] like Figure 4As shown, the end plate 4 is also configured as a bottom plate of the housing 34. In this way, the additional bottom plate of the housing 34 can be omitted, so that the entire fuel cell stack 1 is lighter and has fewer parts. In addition, the end plate 4 is provided with a third sealing element 24, which extends around the periphery of the end plate 4 and surrounds the inlet opening 10 and the outlet opening 12. Since the third sealing element 24 is arranged between the housing 34 and the end plate 4, the hermetic sealing of the housing 34 can be ensured, and water, dust and / or other particles and / or fluids can be prevented or at least reduced from entering the fuel cell stack 1.

[0038] Furthermore, the end plate 4 is provided with a flange 26, which extends around the periphery of the end plate 4. The flange 26 has a plurality of fastening interfaces 30 for fixing the housing to the end plate 4. For example, the fastening interfaces 30 can be threaded holes in the flange, such as threaded through holes or threaded blind holes or through holes through which fastening elements can pass.

[0039] The sealing elements 18a, 18b and the third sealing element 24 are fixed to the end plate 4 by means of corresponding grooves 20a, 20b and 22. By fixing the sealing elements 18a, 18b, 24 to the end plate or (alternatively) the insulating plate 14, the correct positioning of the sealing elements 18a, 18b, 24 can be ensured during the assembly process of the fuel cell stack 1, thereby improving the sealing of the stack. Alternatively, the sealing elements 18a, 18b, 24 can also be fixed to the end plate 4 or the insulating plate 14 by bonding or injection molding.

[0040] The sealing elements 18a, 18b and the third sealing element 24 are all elastic elements compressed in the stacking direction. This has the following advantage: the sealing of the fuel cell stack 1 can be ensured by only applying gravity and / or compression force to the fuel cell stack 1 and / or a part of the fuel cell stack 1.

[0041] Figure 5 shows a partial perspective view of a fuel cell stack 1 according to a second embodiment, Figure 6 A side view of a fuel cell stack 1 according to a second embodiment is shown. Figure 1 The fuel cell stack 1 and Figure 2 The difference of the fuel cell stack 1 is that Figure 2 The fuel cell stack 1 includes a clamping element 28, which is configured to apply an additional force to the insulating plate 14 in the stacking direction, thereby applying an additional force to the first sealing element 18a and the second sealing element 18b. This improves the sealing of the fuel cell stack 1. Figure 5 and Figure 6As shown, the insulating plate 14 is provided with a flange 36, which serves as an interface for the clamping element 28. The clamping element 28 can be a screw or a bolt. The clamping element 28 is arranged so that a portion of the edge of the insulating plate 14 is clamped. This ensures that the seal between the insulating plate 14 and the end plate 4 can be maintained even if the compression of the fuel cell stack 1 becomes loose (for example due to wear and / or breakage). As described above, the sealing elements 18a, 18b and the third sealing element 24 are all arranged on a surface perpendicular to the stacking direction, so that each sealing element 18, 24 is compressed in the stacking direction during assembly and in the assembled state. The advantage of this is that the sufficient sealing of the fuel cell stack 1 can be ensured without the need for precise positioning of the sealing elements.

[0042] Reference numerals

[0043] 1 Fuel cell stack

[0044] 2 Fuel cell stack

[0045] 3 Terminal board

[0046] 4 End plate

[0047] 6 Power output terminal

[0048] 8 End plate

[0049] 10 Entrance opening

[0050] 12 Exit opening

[0051] 14 Insulation board

[0052] 15 Inlet pipe

[0053] 16 Protrusion

[0054] 17 Export pipeline

[0055] 18a, 18b first sealing element

[0056] Grooves 20a, 20b

[0057] 22 additional grooves

[0058] 24 Second sealing element

[0059] 26 Flange

[0060] 28 Clamping element

[0061] 30 Fastening interface

[0062] 32 Insulation board

[0063] 34 Shell

[0064] 36 Flange

Claims

1. A fuel cell stack (1), comprising at least: A fuel cell stack (2) having a plurality of unit fuel cells, wherein each unit fuel cell comprises bipolar plates and membrane electrode assemblies alternately stacked along a stacking direction; A first and a second terminal plate (3) clamping the fuel cell stack (2), wherein the first and the second terminal plates are suitable for collecting electrical energy generated by the fuel cell stack (2); A first insulating plate (14) and a second insulating plate clamping the terminal plate, wherein the insulating plate (14) is adapted to electrically insulate the terminal plate; and The first and second end plates (4) clamp the insulating plate (14), It is characterized in that At least one first sealing element (18a, 18b) is arranged between at least one insulating plate (14) and an adjacent end plate (4).

2. The fuel cell stack (1) according to claim 1, wherein: At least one first sealing element (18a, 18b) is arranged to prevent fluid from entering the space between at least one insulating plate (14) and an adjacent end plate (4) from outside the fuel cell stack (1).

3. The fuel cell stack (1) according to claim 1 or 2, wherein: At least one end plate (4) comprises at least one inlet opening (10) and / or at least one outlet opening (12) for supplying reactants and / or coolants to the fuel cell body (2) and / or outputting reactants and / or coolants from the fuel cell body (2), wherein at least one first sealing element (18a, 18b) extends around the periphery of the at least one inlet opening (10) and / or the at least one outlet opening.

4. A fuel cell stack (1) according to claim 3, wherein at least one insulating plate (14) comprises fuel, oxidant and coolant inlet pipes (15a, 15b, 15c) and fuel, oxidant and coolant outlet pipes (17a, 17b, 17c), wherein the inlet pipes (15a, 15b, 15c) extend into an inlet opening (10) and / or the outlet pipes (17a, 17b, 17c) extend into an outlet opening (12), and / or wherein at least one end plate (4) comprises an opening (10, 12) for each inlet pipe (15) and / or outlet pipe (17) of the insulating plate (14), wherein the inlet pipes and the outlet pipes extend into corresponding openings, and wherein each opening (15, 17) is surrounded by a first sealing element (18).

5. A fuel cell stack (1) according to any one of the preceding claims, wherein: The fuel cell stack (1) further comprises an outer shell, wherein the outer shell comprises at least a bottom plate and a stack cover configured to cover the side surfaces of the fuel cell stack (1).

6. The fuel cell stack (1) according to claim 5, wherein: At least one second sealing element (24) is arranged between the housing and the at least one end plate (4).

7. The fuel cell stack (1) according to claim 5 or 6, wherein one of the end plates (4) is further configured as a bottom plate of the housing.

8. A fuel cell stack (1) according to any one of the preceding claims, wherein: At least one end plate (4) is provided with at least one flange (26), wherein the flange (26) extends around the periphery of the end plate (4).

9. A fuel cell stack (1) according to any one of the preceding claims, wherein: At least one first sealing element (18a, 18b) is arranged on a surface of at least one end plate (4) facing the associated insulating plate (14) and / or on a surface of at least one insulating plate (14) facing the end plate (4).

10. A fuel cell stack (1) according to any one of the preceding claims, wherein: At least a first sealing element and / or a second sealing element (18a, 18b, 24) is fixed to at least one end plate (4) or at least one insulating plate (14).

11. The fuel cell stack (1) according to claim 10, wherein: At least one first sealing element and / or a second sealing element (18a, 18b, 24) is arranged in the groove (20a, 20b, 22) by bonding or injection molding.

12. A fuel cell stack (1) according to any one of the preceding claims, wherein: At least the first sealing element and / or the second sealing element (18a, 18b, 24) is a gasket or an O-ring.

13. A fuel cell stack according to any one of the preceding claims, wherein: At least one of the first sealing element and / or the second sealing element (18a, 18b, 24) is an elastic element compressed in the stacking direction.

14. The fuel cell stack according to claim 13, wherein: At least one first sealing element (18a, 18b) is compressed by weight and / or by at least one compression element, the at least one compression element being configured to provide additional compression force on the fuel cell stack (1).

15. A fuel cell stack according to any one of the preceding claims, wherein: The fuel cell stack comprises at least one clamping element (28), which is configured to apply additional force to at least one insulating plate (14) so ​​that at least one first sealing element (18a, 18b) is further compressed in the stacking direction, wherein, preferably, the clamping element (28) is fixed to at least one end plate (4) by at least one fastening element.

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