Fuel cell graphite half-cell seal structure and stack

Abstract

The utility model relates to a kind of fuel cell graphite half-cell sealing structure, including membrane electrode, bipolar plate and sealing gasket, the bipolar plate includes anode plate and cathode plate, the anode plate is bonded and sealed with membrane electrode by glue layer, multiple sealing grooves are arranged on the cathode plate surface, the sealing gasket is embedded and arranged in the sealing groove, ridge is arranged between adjacent two sealing grooves, when the sealing gasket is pressed, the height of the ridge is less than the height of the sealing gasket after being pressed, cavity is formed between the surface of the ridge and sealing gasket, for guiding leaked gas or cooling liquid to discharge.The utility model effectively improves the sealing performance of electric pile, prevents hydrogen, air and cooling liquid from leaking, and by designing the existence of ridge, cavity is formed between sealing gasket and ridge after being pressed, leaked fluid is guided to discharge, the probability of internal leakage is reduced, and the stability of electric pile operation and the service life of membrane electrode are improved.

Description

Technical Field

[0001] This utility model relates to the field of fuel cell technology, and in particular to a sealed structure for a graphite half-cell fuel cell and a fuel cell stack. Background Technology

[0002] Hydrogen fuel cell stacks, as efficient and clean energy conversion devices, can directly convert the chemical energy of hydrogen into electrical energy. They offer significant advantages such as zero emissions, high efficiency, and low noise, leading to their widespread application in automobiles, power plants, drones, and other fields. A hydrogen fuel cell stack consists of an upper end plate, upper insulating plate, upper current collector, core, lower current collector, lower insulating plate, lower end plate, and fasteners. The core is the power generation part of the stack, formed by stacking a certain number of bipolar plates and membrane electrode assemblies (MEAs). The bipolar plates provide rigid support for the core, separate different fluids, and guide the fluid to be evenly distributed within the bipolar plate flow field region; the MEAs are the sites where electrochemical reactions occur.

[0003] However, existing hydrogen fuel cell stack sealing technologies face several pressing issues. Conventional core sealing primarily relies on compression sealing between the bipolar plates and the membrane electrode assembly (MEA). This involves placing sealing strips on both the anode and cathode sides of the bipolar plates, and using the compressive forces during stack assembly to compress these strips, thus achieving a seal. This sealing method is prone to leakage during stack operation, especially under high pressure and thermal cycling conditions. The material properties of the sealing strips deteriorate rapidly under these conditions, leading to permanent deformation and a significant increase in the risk of stack leakage.

[0004] More seriously, because the pressure in the hydrogen chamber is typically higher than that in the air chamber during fuel cell operation, hydrogen can slowly leak into the air chamber when the sealing performance of the sealing strip deteriorates, mixing with oxygen in the air and reacting. This not only reduces the lifespan of the membrane electrode assembly (MEA) but can also lead to serious safety accidents. To address this issue, some half-cell structures use a method of bonding the anode side of the bipolar plate to the MEA to replace the sealing strip on the anode side. While this improvement enhances the sealing effect on the anode side to some extent and reduces the probability of hydrogen leakage, the sealing strip on the cathode side still exists. Hydrogen can still cross the sealing strip on the cathode side and enter the cathode, reacting with air and affecting the MEA's lifespan. Utility Model Content

[0005] Therefore, the technical problem to be solved by this utility model is to overcome the problems of insufficient sealing performance and low reliability in the prior art. It proposes a fuel cell half-cell bonding and sealing structure and a fuel cell stack, which improves the sealing performance of the stack, prevents leakage between hydrogen, air and coolant, and the presence of ridges in the design allows the sealing gasket to form a cavity with the ridge after being compressed, guiding the leakage fluid to be discharged, reducing the probability of internal leakage, and improving the stability of stack operation and the service life of membrane electrode assembly.

[0006] To address the aforementioned technical problems, this utility model provides a sealed structure for a graphite half-cell fuel cell, comprising a membrane electrode assembly (MEA), a bipolar plate, and a sealing gasket. The bipolar plate includes an anode plate and a cathode plate. The anode plate is bonded and sealed to the MEA via an adhesive layer. The cathode plate has multiple sealing grooves on its surface, and the sealing gasket is embedded within these grooves. A ridge is provided between adjacent sealing grooves. When the sealing gasket is compressed, the height of the ridge is less than the height of the sealed gasket after compression. A cavity is formed between the surface of the ridge and the sealing gasket to guide leaked gas or coolant out.

[0007] In one embodiment of this utility model, the height of the ridge is flush with the surface of the cathode plate, and the height of the sealing gasket is greater than the surface of the cathode plate; when the sealing gasket is compressed, the height of the sealing gasket is greater than the surface of the cathode plate and the height of the ridge, so that the sealing gasket and the surface of the ridge form a cavity.

[0008] In one embodiment of this utility model, the height of the ridge is less than the surface of the cathode plate, and the height of the sealing gasket is greater than the surface of the cathode plate; when the sealing gasket is compressed, the height of the sealing gasket remains flush with the surface of the cathode plate, so that a cavity is formed between the sealing gasket and the surface of the ridge.

[0009] In one embodiment of the present invention, a groove is provided at the edge of the cathode plate. When the sealing gasket is flattened to be flush with the surface of the cathode plate, the cavity communicates with the groove to allow the leaked fluid to flow to the outside along the cavity.

[0010] In one embodiment of this utility model, the depth of the groove is the same as the height of the ridge.

[0011] In one embodiment of this utility model, the sealing groove on the cathode plate includes an air sealing groove, a coolant sealing groove, a hydrogen sealing groove, and a reaction zone sealing groove.

[0012] In one embodiment of this utility model, the air sealing groove, coolant sealing groove, hydrogen sealing groove and reaction zone sealing groove are independent of each other and adjacent sealing grooves are not connected.

[0013] In one embodiment of this utility model, the sealing gasket includes a hydrogen sealing strip, a cooling sealing strip, an air sealing strip, and a reaction zone sealing strip, and the number of each of the hydrogen sealing strip, the cooling sealing strip, and the air sealing strip is two.

[0014] In one embodiment of this utility model, the hydrogen sealing strip, the cooling sealing strip, the air sealing strip, and the reaction zone sealing strip are all independent structures, and there are gaps between adjacent sealing strips.

[0015] Secondly, in order to solve the above-mentioned technical problems, this utility model discloses a fuel cell stack, including the fuel cell graphite half-cell sealed structure described in the first aspect.

[0016] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects: The fuel cell graphite half-cell sealing structure and stack described in this utility model effectively improve the sealing performance of the stack by bonding and sealing the anode plate with the membrane electrode assembly through the adhesive layer, and by designing multiple sealing grooves and gaskets on the cathode plate, preventing leakage between hydrogen, air and coolant. Furthermore, the presence of ridges allows the gaskets to form a cavity with the ridges under pressure, guiding the leakage fluid out, reducing the probability of internal leakage, extending the service life of the membrane electrode assembly, and thus extending the service life of the stack and reducing the failure rate of the stack. Attached Figure Description

[0017] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. Figure 1 This is an exploded structural diagram of the sealed graphite half-cell structure of the fuel cell in a preferred embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the sealing gasket of the utility model; Figure 3 This is a schematic diagram of the cathode plate in Embodiment 1 of this utility model; Figure 4 for Figure 3 The cavity structure between the sealing strip and the ridge at point A of the intermediate cathode plate; Figure 5 This is a schematic diagram of the cathode plate in Embodiment 2 of this utility model; Figure 6 for Figure 5 The cavity structure between the sealing strip and the ridge at point B of the intermediate cathode plate; Figure 7 This is a schematic diagram of the structure of the fuel cell stack in this utility model; Explanation of reference numerals in the accompanying drawings: 1. Membrane electrode; 2. Bipolar plate; 21. Anode plate; 22. Cathode plate; 221. Ridge; 222. Groove; 223. First air seal groove; 224. Second air seal groove; 225. First coolant seal groove; 226. Second coolant seal groove; 227. First hydrogen seal groove; 228. Second hydrogen seal groove; 229. Reaction zone seal groove; 3. Adhesive layer; 4. Sealing gasket; 4 1. First hydrogen sealing strip; 42. First cooling sealing strip; 43. First air sealing strip; 44. Reaction zone sealing strip; 45. Second air sealing strip; 46. Second cooling sealing strip; 47. Second hydrogen sealing strip; 100. Cavity; 101. Upper end plate; 102. Upper insulating plate; 103. Current collector plate; 104. Stack core; 105. Current collector plate; 106. Lower insulating plate; 107. Lower end plate. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention. Example 1

[0019] Reference Figure 1-4 As shown, this utility model provides a sealed structure for a graphite half-cell fuel cell, including a membrane electrode 1, a bipolar plate 2, and a sealing gasket 4. The bipolar plate 2 includes an anode plate 211 and a cathode plate 22. The anode plate 21 is bonded and sealed to the membrane electrode 1 by an adhesive layer 3. The cathode plate 22 has multiple sealing grooves on its surface. The sealing gasket 4 is embedded in the sealing grooves. A ridge 221 is provided between two adjacent sealing grooves. When the sealing gasket 4 is compressed, the height of the ridge 221 is less than the height of the sealing gasket 4 after compression. A cavity 100 is formed between the surface of the ridge 221 and the sealing gasket 4 for guiding leaked gas or coolant out.

[0020] The height of the ridge 221 is flush with the surface of the cathode plate 22, while the height of the sealing gasket 4 is greater than the surface of the cathode plate 22. When the sealing gasket 4 is compressed, its height remains greater than the surface of the cathode plate 22, forming a cavity 100 between the sealing gasket 4 and the surface of the ridge 221. Because the ridge 221 is flush with the surface of the cathode plate 22, and the sealing gasket 4 is greater than the surface of the cathode plate 22, this design ensures that an effective cavity 100 can be formed between the ridge 221 and the sealing gasket 4 when compressed. This cavity 100 helps guide leaked fluid out, preventing it from entering the reaction zone, further enhancing the sealing reliability and operational safety of the fuel cell stack.

[0021] In this embodiment, the sealing grooves on the cathode plate 22 include a first air sealing groove 223, a second air sealing groove 224, a first coolant sealing groove 225, a second coolant sealing groove 226, a first hydrogen sealing groove 227, a second hydrogen sealing groove 228, and a reaction zone sealing groove 229. These sealing grooves are independent of each other, and adjacent sealing grooves are not connected. This independent design effectively prevents cross-contamination or leakage between different fluids, significantly improving the sealing performance of the fuel cell stack and ensuring that each fluid flows independently in its respective channel, thereby improving the operating efficiency and stability of the fuel cell stack.

[0022] The sealing gasket 4 includes a first hydrogen sealing strip 41, a first cooling sealing strip 42, a first air sealing strip 43, a reaction zone sealing strip 44, a second air sealing strip 45, a second cooling sealing strip 46, and a second hydrogen sealing strip 47. All of these sealing strips are independent structures, with gaps between adjacent sealing strips. This design further refines the sealing structure, ensuring that each sealing strip can function independently under pressure, improving the sealing effect. Simultaneously, the gap design helps avoid mutual interference between adjacent sealing strips, further reducing the risk of leakage.

[0023] In this embodiment, the presence of ridge 221 ensures that the sealing grooves are independent of each other, preventing the sealing strips from interfering with each other. This confines the sealing strips within their respective sealing grooves, preventing displacement of the sealing gasket base when the fuel cell stack is under pressure, thus avoiding any impact on sealing performance. In this embodiment, the first hydrogen sealing strip 41, the first cooling sealing strip 42, the first air sealing strip 43, the reaction zone sealing strip 44, the second air sealing strip 45, the second cooling sealing strip 46, and the second hydrogen sealing strip 47 are all embedded into their respective sealing grooves by adhesive bonding. Example 2

[0024] like Figure 5 and 6 As shown, the height of the ridge 221 is less than the surface of the cathode plate 22, and the height of the sealing gasket 4 is greater than the surface of the cathode plate 22. When the sealing gasket 4 is compressed, its height remains flush with the surface of the cathode plate 22, forming a cavity 100 between the sealing gasket 4 and the surface of the ridge 221. Because the height of the ridge 221 is lower than the surface of the cathode plate 22, this structure ensures that even under extreme conditions, when the sealing gasket 4 is compressed to be flush with the surface of the cathode plate 22, a cavity 100 is formed between the ridge 221 and the sealing gasket 4, further reducing the possibility of leakage between hydrogen, air, or coolant, and improving the overall safety of the fuel cell stack.

[0025] The cathode plate 22 has a groove 222 at its edge. When the sealing gasket 4 is flattened to be flush with the surface of the cathode plate 22, the cavity 100 communicates with the groove 222, allowing leaked fluid to flow outward along the cavity 100. This design not only effectively guides the leaked fluid outward but also prevents it from accumulating inside the fuel cell stack, further reducing the risk of internal leakage and improving the stability and reliability of the fuel cell stack operation.

[0026] In this embodiment, the depth of the groove 222 is the same as the height of the ridge 221. This design ensures that after the sealing gasket 4 is compressed, the leaking fluid can flow smoothly along the cavity to the groove 222 and be discharged outside the fuel cell stack. This optimized design not only enhances the sealing performance of the fuel cell stack, but also effectively prevents the leaking fluid from entering the reaction zone, further improving the safety and stability of the fuel cell stack.

[0027] The present invention also provides a fuel cell stack, the structure of which is as follows: Figure 7 As shown, the fuel cell stack consists of an upper end plate 101, an upper insulating plate 102, a current collector plate 103, a fuel cell stack core 104, a current collector plate 105, a lower insulating plate 106, a lower end plate 107, and fasteners. The fuel cell stack core 104 is the power generation part of the fuel cell stack, which is formed by stacking the graphite half-cell sealed structure of the fuel cell in this embodiment.

[0028] By applying the aforementioned graphite half-cell sealing structure to the fuel cell stack, the sealing performance of the stack is significantly improved, the risk of leakage of hydrogen, air and coolant is greatly reduced, the stack degradation rate can be reduced, the lifespan can be extended, and the overall performance and safety of the fuel cell stack can be enhanced.

[0029] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A sealed structure for a graphite half-cell fuel cell, characterized in that, The device includes a membrane electrode, a bipolar plate, and a sealing gasket. The bipolar plate includes an anode plate and a cathode plate. The anode plate is bonded and sealed to the membrane electrode by an adhesive layer. The cathode plate has multiple sealing grooves on its surface. The sealing gasket is embedded in the sealing grooves. A ridge is provided between two adjacent sealing grooves. When the sealing gasket is compressed, the height of the ridge is less than the height of the sealing gasket after compression. A cavity is formed between the surface of the ridge and the sealing gasket to guide leaked gas or coolant out.

2. The sealed structure of a graphite half-cell for a fuel cell according to claim 1, characterized in that, The height of the ridge is flush with the surface of the cathode plate, and the height of the sealing gasket is greater than the surface of the cathode plate; when the sealing gasket is compressed, the height of the sealing gasket is greater than the surface of the cathode plate and the height of the ridge, so that the sealing gasket and the surface of the ridge form a cavity.

3. The sealed structure of a graphite half-cell for a fuel cell according to claim 1, characterized in that, The height of the ridge is less than the surface of the cathode plate, and the height of the sealing gasket is greater than the surface of the cathode plate; when the sealing gasket is compressed, the height of the sealing gasket remains flush with the surface of the cathode plate, so that a cavity is formed between the sealing gasket and the surface of the ridge.

4. The sealed structure of a graphite half-cell for a fuel cell according to claim 3, characterized in that, The cathode plate has a groove at its edge. When the sealing gasket is flattened to be flush with the surface of the cathode plate, the cavity communicates with the groove to allow leaked fluid to flow outward along the cavity.

5. The sealed structure of a graphite half-cell for a fuel cell according to claim 4, characterized in that, The depth of the groove is the same as the height of the ridge.

6. The fuel cell graphite half-cell sealed structure according to claim 1, characterized in that, The sealing grooves on the cathode plate include an air sealing groove, a coolant sealing groove, a hydrogen sealing groove, and a reaction zone sealing groove.

7. The fuel cell graphite half-cell sealed structure according to claim 6, characterized in that, The air sealing groove, coolant sealing groove, hydrogen sealing groove and reaction zone sealing groove are independent of each other and are not connected to adjacent sealing grooves.

8. The fuel cell graphite half-cell sealed structure according to claim 1, characterized in that, The sealing gasket includes a hydrogen sealing strip, a cooling sealing strip, an air sealing strip, and a reaction zone sealing strip, and there are two of each of the hydrogen sealing strip, the cooling sealing strip, and the air sealing strip.

9. The fuel cell graphite half-cell sealed structure according to claim 8, characterized in that: The hydrogen sealing strip, cooling sealing strip, air sealing strip, and reaction zone sealing strip are all independent structures, with gaps between adjacent sealing strips.

10. A fuel cell stack, characterized in that, It includes at least one sealed structure for a fuel cell graphite half-cell as described in any one of claims 1-9.

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