A sealing plug-in for improving the air tightness of a fuel cell stack and a method of using the same

Abstract

The present invention provides a sealing plug-in for improving the air tightness of a fuel cell stack and a method for using the sealing plug-in. The sealing plug-in includes a frame body arranged in the direction of the guide groove near the fuel chamber and the oxidant chamber, which is a semi-enclosed structure opened along one side of the guide groove; a sealing member arranged on the wall surface of the frame body on the side of the frame body opening; a supporting fastening structure arranged in the frame body along the length direction of the frame body, including a fastening structure with an internal thread and a supporting rib arranged between the outer side of the fastening structure and the frame body, the fastening structure and the screw rod being fastened together; a sealing end head arranged in the direction of the guide groove near the end plate of the fuel cell stack, and a sealing gasket is also arranged at the sealing end head. After the stack is assembled, the sealing plug-in is placed in the common pipeline of the fuel chamber and the oxidant chamber, and can also be placed in the common pipeline of the coolant chamber, and the sealing plug-in is sealed at the end plate of the stack, so as to improve the high air tightness of the stack, reduce the safety hazard of hydrogen leakage, and provide safety guarantee for the popularization and application of the fuel cell stack.

Description

Technical Field

[0001] The present invention relates to the technical field of proton exchange membrane fuel cells (PEMFC), and in particular to a sealing plug-in for improving the air tightness of a fuel cell stack and a method for using the same. Background Art

[0002] The fuel cell stack (or battery pack) is the core of the entire fuel cell system. Its basic component unit is a single cell, and each single cell is composed of bipolar plates, membrane electrode assemblies (MEA), and seals. In order to meet certain power output requirements, fuel cell stacks often have dozens or even hundreds of single cells, which are assembled in the manner of a filter press. As the number of stack sections increases, the height of the stack increases, the number of stack sealing lines increases, and the number of leakage points also increases. The number of sealing lines of a stack of hundreds of sections can reach hundreds. After the stack is assembled, there is a great risk of gas leakage during its transfer, transportation, and subsequent use.

[0003] Generally, fuel cell stacks are sealed with rubber rings. Since hydrogen molecules are small and easily dissolved in rubber, they leak out, especially in the common pipelines of the fuel chamber at the inlet and outlet. Therefore, airtightness is one of the decisive factors for battery safety. Although airtightness testing is required after the stack is assembled, the stack is then transferred and transported to the test bench, and fuel, oxidant, coolant, etc. are introduced to test whether the leakage index is qualified. However, as the sealing ring is used or the high and low temperatures change frequently, its elasticity fails after stress deformation, etc., even if the airtightness of the stack meets the standard during assembly, there is a possibility of leakage during subsequent use. Therefore, after the assembled stack is tested and qualified, it is necessary to further increase the sealing structure to reduce the possibility of leakage during subsequent use.

[0004] Invention patent CN201510034364.6 discloses a proton exchange membrane fuel cell seal design and manufacturing method. The method uses a resin sheet of uniform thickness for each cell in a PEM fuel cell. The method provides a step of preparing a sheet of a resin material layer, wherein the folds formed by the sheet are folded toward a flat portion to form a composite fold to form a gasket. The composite fold is placed between a first fuel cell component and a second fuel cell component to form a seal therein. Like many other patents, this patent only considers the seal between single cells.

[0005] Invention patent CN201110274791.3 proposes a proton exchange membrane fuel cell sealing structure, which is a self-locking fuel cell sealing component structure, mainly for fuel cell monomers, and designs a concave structure in the cross-sectional shape of the upper sealing ring and the lower sealing ring of the single cell, and is bonded and fixed to the electrode plate by an adhesive layer. The patent also does not consider the overall sealing design of the fuel cell stack.

[0006] Therefore, in view of the overall sealing requirements of the fuel cell stack, it is necessary to propose a method of overall sealing plug-in, so as to further improve the airtightness of the fuel cell stack and further improve the safety of the fuel cell stack. Summary of the invention

[0007] According to the above technical problem that the existing technology rarely considers the overall airtightness of the stack, a sealing plug-in and a method of using the sealing plug-in are provided to improve the airtightness of the fuel cell stack. The present invention mainly sets a sealing plug-in in the common pipeline of the fuel chamber and the oxidant chamber of the stack; the sealing plug-in structure is attached to the inner wall of the fuel chamber and the oxidant chamber of the stack; the length of the sealing plug-in is substantially the same as the height of the common pipeline of the fuel chamber and the oxidant chamber of the stack; by placing a sealing material on the edge of the sealing plug-in, and then putting the sealing plug-in with the sealing material into the common pipeline for curing, gas leakage can be effectively prevented, so that the fuel cell stack has better airtightness and the safety of the proton exchange membrane fuel cell is improved.

[0008] The technical means adopted by the present invention are as follows:

[0009] A sealing plug-in for improving the air tightness of a fuel cell stack, comprising:

[0010] A frame body is provided in the fuel cavity and the oxidant cavity, and is a semi-enclosed structure with an opening along one side of the guide groove;

[0011] A sealing member, arranged on the frame wall surface on the frame opening side, and used for sealing with the edges of the guide grooves of the fuel chamber and the oxidant chamber;

[0012] A supporting fastening structure is arranged inside the frame along the length direction of the frame, comprising a fastening structure with an internal thread and a supporting rib arranged between the outer side of the fastening structure and the frame, wherein the fastening structure cooperates with the screw to fasten;

[0013] The sealing end head is arranged in the direction of the guide groove near the end plate of the fuel cell stack, that is, it is arranged at one end of the frame body. It is a closed structure and is used for sealing the inlet and outlet of the fuel chamber and the oxidant chamber of the fuel chamber. A sealing gasket is also provided at the sealing end head.

[0014] Furthermore, the sealing plug-in is a resin, rubber or a built-in metal structure thereof, and the sealing plug-in is placed in a common pipe of the fuel chamber and the oxidant chamber of the stack. Preferably, the resin can be one of polypropylene, polysulfone, polyoxymethylene, ABS, nylon, phenolic resin or epoxy resin.

[0015] Furthermore, an outer side of the sealing end head is provided with an outer edge, and the outer edge and the sealing gasket are a separate structure or an integrated structure.

[0016] Furthermore, the sealing gasket is at least one of liquid glue or rubber sheet.

[0017] Furthermore, the liquid glue is one of single-component silicone rubber, two-component silicone rubber, and silicone glue; the rubber sheet is one of silicone rubber, EPDM rubber, or fluororubber.

[0018] Furthermore, when the sealing plug-in is injection molded with a rubber-embedded metal structure, the outer edge and the cushion skin of the sealing plug-in can be an integrated structure. The sealing plug-in can be injection molded or 3D printed.

[0019] Furthermore, the sealing member is arranged on the wall surface of the frame at the opening side of the frame, tightly attached to the edge of the guide groove, and is used for sealing with the fuel cavity and the oxidant cavity.

[0020] Furthermore, after the screw rod is completely fastened to the fastening structure, its outer end is inside the inlet and outlet of the fuel cell stack end plate.

[0021] As a preferred solution, the sealing plug-in can be placed in the coolant cavity as well as the fuel cavity of the fuel cell stack, which can reduce metal ion contamination of the common pipeline of the stack and improve the insulation resistance of the stack.

[0022] The present invention also discloses a method for improving the air tightness of a fuel cell stack, which comprises respectively arranging the above-mentioned sealing plug-ins on the common pipelines of the fuel chamber and the oxidant chamber of the fuel cell stack to prevent gas leakage.

[0023] The sealing plug-in of the present invention can effectively prevent the gas leakage of the fuel cell stack and can greatly improve the safety of the proton exchange membrane fuel cell.

[0024] The present invention is to place the sealing plug-in in the fuel chamber and oxidant chamber of the fuel cell stack, or in the coolant chamber, after the electrodes and bipolar plates of the fuel cell are assembled into a stack and the stack end plate is fastened with screws, so as to reduce gas leakage and metal ion contamination of the common pipeline of the stack. By screwing the non-metallic screw of the sealing plug-in to a certain position, the supporting ribs of the fastening structure are pressed against the sealing member on the outside of the guide groove through hole, so that it is tightly pressed against the edge of the guide groove, resulting in that the gas or coolant in the common pipeline of the stack is limited to the side of the common pipeline of the stack facing the guide groove, and the other surfaces in the common pipeline of the stack cannot contact the gas or coolant. When the sealing member on the outside of the guide groove through hole is pressed, the non-metallic screw is completely immersed in the end plate of the stack, ensuring the sealing of the joint of the end plate of the stack.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The process of the present invention is simple. The plug-in is directly placed into the fuel cavity and the air cavity, and the opening of the plug-in is sealed.

[0027] 2. The present invention has good sealing effect. Compared with the fuel cell stack without adding plug-ins, this method reduces the contact area between the gas path inside the fuel cell stack and the gas by 75%, effectively improving the sealing of the fuel cell stack.

[0028] In summary, the fuel cell stack of the present invention has good air tightness, can effectively prevent gas leakage, and improves the safety of the proton exchange membrane fuel cell.

[0029] Based on the above reasons, the present invention can be widely promoted in the field of proton exchange membrane fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is a top view of the sealing insert of the present invention.

[0032] Figure 2 It is a schematic diagram of the structure of the sealing plug-in of the present invention.

[0033] Figure 3 It is a schematic diagram of the sealing plug-in and the battery stack of the present invention.

[0034] Figure 4 This is a schematic diagram of the sealing plug-in and the battery stack after assembly according to the present invention.

[0035] Figure 5 It is a schematic diagram of the fuel chamber, oxidant chamber and coolant chamber sealing plug-ins of the fuel cell stack after being assembled with the stack of the present invention.

[0036] In the figure: 1. through hole; 2. sealing part; 3. supporting rib; 4. supporting structure; 5. fastening structure; 6. screw; 7. sealing gasket; 8. outer edge; 9. inlet and outlet of oxidant cavity of fuel cell stack end plate; 10. inlet and outlet of fuel cavity of fuel cell stack end plate; 11. inlet and outlet of coolant cavity of fuel cell stack end plate. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0041] like Figure 1 and Figure 2 As shown, the present invention provides a sealing plug-in for improving the air tightness of a fuel cell stack, comprising:

[0042] The frame (shown as the shaded part in the figure) is arranged in the fuel cavity and the oxidant cavity, and an opening is arranged along one side of the guide groove. The semi-enclosed structure of the frame forms a Figure 1 The structure of the rectangular through hole 1 is shown.

[0043] The sealing member 2 is arranged on the wall surface of the frame body at the opening side of the frame body (such as Figure 2As shown, the frame part on the rear side of the sealing gasket 7 is used to seal with the edges of the guide grooves of the fuel chamber and the oxidant chamber; the sealing member 2 is arranged on the frame wall surface on the opening side of the frame, tightly attached to the edge of the guide groove, for sealing with the fuel chamber and the oxidant chamber.

[0044] The supporting fastening structure is arranged in the frame along the length direction of the frame, including a fastening structure 5 with an internal thread and a supporting rib 3 arranged between the outer side of the fastening structure 5 and the frame. As shown in the figure, at least three ribs are arranged, two of which are arranged at the edge of the through hole 1 in the direction of the guide groove, and combined with the frame to play a supporting role (at Figure 2 In the middle, the shape is like a fish bone), and the other one is in the opposite direction of the guide groove. A support structure 4 is also provided on the support rib 3. The sealing plug-in is fastened by a non-metallic screw 6 passing through the thread, that is, the fastening structure 5 is fastened with the screw 6 (non-metallic screw);

[0045] The sealing end head is arranged in the direction of the guide groove near the end plate of the fuel cell stack, that is, it is arranged at one end of the frame body, and does not need to be opened to be a closed structure, and is used for sealing the inlet and outlet of the fuel chamber and the oxidant chamber of the fuel cell stack. The outer side of the sealing end head is provided with an outer edge 8, and the outer edge 8 and the sealing gasket 7 are a split structure or an integrated structure. The sealing end head is also provided with a sealing gasket 7. After the non-metallic screw 6 of the sealing plug-in is tightened, the sealing gasket 7 can play a sealing role to prevent the fuel and oxidant from flowing out from the outside of the sealing plug-in. After the screw and the fastening structure are completely tightened, the outer end thereof is inside the inlet and outlet of the end plate of the fuel cell stack.

[0046] The sealing gasket 7 is at least one of liquid glue or rubber sheet. The liquid glue is one of single-component silicone rubber, two-component silicone rubber, and silicone rubber; the rubber sheet is one of silicone rubber, EPDM rubber, or fluororubber.

[0047] The sealing plug-in is a resin, rubber or a built-in metal structure thereof, and the sealing plug-in is placed in the common pipe of the fuel chamber and the oxidant chamber of the stack. Preferably, the resin can be one of polypropylene, polysulfone, polyoxymethylene, ABS, nylon, phenolic resin or epoxy resin.

[0048] Example 1

[0049] The sealing plug-in of the present invention is 3D printed and made of nylon. The sealing plug-in is placed in the common pipeline of the fuel chamber and oxidant chamber of a 5kW fuel cell stack, and the sealing plug-in is fastened to the fuel chamber and oxidant chamber of the fuel cell stack by screwing the nylon screw on the sealing plug-in support structure. The sealing member at the guide groove of the sealing plug-in adopts a 0.3mm silicone rubber sheet, and the sealing gasket 7 at the inlet and outlet of the fuel chamber and the oxidant chamber of the stack is an EPDM rubber sheet. When the screw 6 on the support structure 5 is tightened, the support rib 3 acts on the guide groove to play a sealing role, and the screw 6 is completely on the inside of the stack end plate. Then, the inlet and outlet of the stack end plate (such as Figure 3 , Figure 4 After the joint is assembled and tightened, the end plate joint acts on the outer edge of the sealing plug-in, and the outer edge is pressed on the EPDM rubber sheet to play a sealing role. The helium leak detector is used to analyze the leakage of the 5kW fuel cell stack. Its airtightness is 1.3×10 -7 pa·m 3 / s, reduced to 3.2×10 -8 pa·m 3 / s, the stack leakage is significantly reduced.

[0050] Example 2

[0051] The sealing plug-in of the present invention adopts a silicone rubber built-in stainless steel structure, and is injection molded. The screw on the support structure 5 is a polysulfone resin, and the sealing plug-in and the seal at the guide groove are an integrated silicone rubber structure. The sealing plug-in is placed in the common pipeline of the fuel chamber, oxidant chamber and coolant chamber of a 30kW fuel cell stack, and the sealing plug-in is fastened to the fuel chamber and oxidant chamber of the fuel cell stack by screwing the polysulfone screw on the sealing plug-in support structure. No pads are required for the outer edges of the inlet and outlet of the fuel chamber, oxidant chamber and coolant chamber of the stack. When the screw on the support structure is tightened, the support ribs act on the guide groove to play a sealing role, and the screw is completely on the inside of the stack end plate. Then, after the inlet and outlet joints of the stack end plate are assembled and tightened, the end plate joint acts on the outer edge of the sealing plug-in, and the outer edge of the silicone rubber is subjected to force to directly play a sealing role. A helium leak detector was used to analyze the leakage of the 30kW fuel cell stack, and its airtightness was compared with 8.6×10 -7 pa·m 3 / s, reduced to 4.1×10 -8 pa·m 3 / s, the leakage of the stack is significantly reduced. In addition, since the coolant cavity of this embodiment is also equipped with a sealing plug-in, such as Figure 5As shown, after 100 hours of use, the ionic conductivity of the cooling water of the 30kW fuel cell stack is 8mS / cm and 9mS / cm before and after placement, respectively. This indicates that the ion content entering the cooling water is significantly reduced, and the sealing plug-in can also help the fuel cell stack reduce metal ion contamination in the common pipeline.

[0052] The present invention designs a sealing plug-in that can fit the common pipeline of the stack according to the size of the fuel chamber and oxidant chamber of the stack and the common pipeline of the stack, and a through hole is set in the sealing plug-in near the guide groove of the fuel chamber and the oxidant chamber. After the stack is assembled, the sealing plug-in is placed in the common pipeline of the fuel chamber and the oxidant chamber, and can also be placed in the common pipeline of the coolant chamber, and the sealing plug-in is sealed at the end plate of the stack. The present invention can achieve high air tightness of the stack, reduce the safety hazard of hydrogen leakage, and can also reduce metal ion contamination of the common pipeline, providing safety guarantee for the promotion and application of fuel cell stacks.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sealing plug-in for improving the air tightness of a fuel cell stack, characterized in that: include: The frame is provided in the fuel cavity and the oxidant cavity, and is a semi-enclosed structure with an opening along one side of the guide groove; A sealing member, arranged on the frame wall surface on the frame opening side, and used for sealing with the edges of the guide grooves of the fuel chamber and the oxidant chamber; A supporting fastening structure is arranged inside the frame along the length direction of the frame, comprising a fastening structure with an internal thread and a supporting rib arranged between the outer side of the fastening structure and the frame, wherein the fastening structure cooperates with the screw to fasten; The sealing end head is arranged in the direction of the guide groove near the end plate of the fuel cell stack, that is, it is arranged at one end of the frame body. It is a closed structure and is used for sealing the inlet and outlet of the fuel chamber and the oxidant chamber of the fuel chamber. A sealing gasket is also provided at the sealing end head.

2. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 1, characterized in that: The sealing plug-in is a resin, rubber or a built-in metal structure thereof, and the sealing plug-in is placed in a common pipeline between the fuel chamber and the oxidant chamber of the fuel cell stack.

3. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 1, characterized in that: An outer side of the sealing end head is provided with an outer edge, and the outer edge and the sealing gasket are a separate structure or an integrated structure.

4. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 3, characterized in that: The sealing gasket is at least one of liquid glue or rubber sheet.

5. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 4, characterized in that: The liquid glue is one of single-component silicone rubber, two-component silicone rubber and silicone glue; the rubber sheet is one of silicone rubber, EPDM rubber or fluororubber.

6. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 1, characterized in that: The sealing member is arranged on the wall surface of the frame body at the opening side of the frame body and is closely attached to the edge of the guide groove, and is used for sealing with the fuel cavity and the oxidant cavity.

7. The sealing plug-in for improving the air tightness of a fuel cell stack according to claim 1, characterized in that: After the screw rod is completely fastened to the fastening structure, the outer end thereof is inside the inlet and outlet of the end plate of the fuel cell stack.

8. A method for improving the air tightness of a fuel cell stack, characterized in that: A sealing plug-in as claimed in any one of claims 1 to 7 is respectively arranged in the common pipeline of the fuel chamber and the oxidant chamber of the fuel cell stack to prevent gas leakage.

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