Fuel cell sealing structure, single cell, electric pile and fuel cell system

Abstract

The utility model provides a fuel cell sealing structure, a single cell, an electric pile and a fuel cell system. The fuel cell sealing structure comprises a sealing strip arranged between a frame of a membrane electrode and a bipolar plate. Wherein the frame of the membrane electrode is provided with a limiting groove, and at least part of the sealing strip is arranged in the limiting groove and used for sealing a gap between the frame of the membrane electrode and the bipolar plate. According to the fuel cell sealing structure disclosed by the utility model, the limiting groove is formed in the frame of the membrane electrode, and at least part of the sealing strip is arranged in the limiting groove, so that the sealing strip can be effectively prevented from being misplaced in a press-fitting process, the sealing performance is favorably ensured, the ridge-to-ridge contact area is favorably ensured, and the contact resistance is reduced; therefore, the pile performance can be ensured; meanwhile, in the assembling process, the sealing strip can be rapidly installed in the limiting groove, and the assembling efficiency can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to a fuel cell sealing structure. At the same time, the utility model also relates to a single cell provided with the fuel cell sealing structure, as well as a battery stack and a fuel cell system. Background Art

[0002] Proton exchange membrane fuel cells (PEMFCs) convert chemical energy into electrical energy through an electrochemical reaction between fuel gases such as hydrogen and air. The core components of a PEM fuel cell stack are the membrane electrode and bipolar plates, which are stacked together. The bipolar plates provide inlet and outlet channels for gases and ensure that the gases are distributed as evenly as possible. Furthermore, the bipolar plates are typically made of conductive materials with good electrical conductivity and corrosion resistance, ensuring smooth gas flow within the stack. The membrane electrode, on the other hand, provides a place for the electrochemical reaction between the fuel gas and air to occur.

[0003] In proton exchange membrane fuel cells, the sealing between the bipolar plate and the frame of the membrane electrode is crucial. If the sealing is poor, gas and oxidant leakage will occur, which not only reduces the performance and efficiency of the battery, but also may pose a safety hazard. In traditional fuel cell stacks, the bipolar plate anode strip, the frame of the membrane electrode, and the bipolar plate cathode strip are in contact with each other. Therefore, during the press-fitting process of the proton exchange membrane fuel cell, when the bipolar plate slips and dislocates laterally, the relative area of ​​the ridges between the flow channels will decrease, which can easily lead to a reduction in the effective area for gas transmission and reaction. The flow of gas in the flow channel may be hindered, affecting the uniform distribution of gas and oxidant, thereby reducing the efficiency of the electrochemical reaction and affecting the performance of the entire fuel cell. Utility Model Content

[0004] In view of this, the present invention aims to provide a fuel cell sealing structure that can effectively prevent the sealing strip from being misplaced and improve the sealing effect.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0006] A fuel cell sealing structure includes a sealing strip provided between a frame of a membrane electrode and a bipolar plate;

[0007] A limiting groove is provided on the frame of the membrane electrode, and at least part of the sealing strip is arranged in the limiting groove and is used to seal the gap between the frame of the membrane electrode and the bipolar plate.

[0008] Furthermore, the sealing strip includes an abutting portion abutting against the bipolar plate, and a protruding portion protruding toward one side of the frame of the membrane electrode;

[0009] The width of the protruding portion is smaller than the width of the abutting portion, and the protruding portion is inserted into the limiting groove.

[0010] Furthermore, the protruding portion is located in the middle of the abutting portion in the width direction, and the width K of the limiting groove and the width L of the protruding portion satisfy: K=L+(0.08-0.1) mm.

[0011] Furthermore, a sealing groove is provided on the bipolar plate, the sealing strip is provided in the sealing groove, and both sides of the abutting portion in a width direction abut against the side walls of the sealing groove.

[0012] Furthermore, the cross-sections of the abutting portion and the protruding portion are both rectangular; and / or,

[0013] A convex rib is provided on a side of the protruding portion away from the abutting portion, and the convex rib extends along the length direction of the protruding portion.

[0014] Furthermore, the convex ribs are multiple and spaced apart along the width direction of the protruding portion.

[0015] Furthermore, the frame of the membrane electrode comprises a frame body and outer frames provided on two opposite sides of the frame body;

[0016] The outer frame is used to constrain the gas diffusion layer, and the limiting groove is arranged on the outer frame.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The fuel cell sealing structure described in the present invention, by providing a limiting groove on the frame of the membrane electrode and allowing at least part of the sealing strip to be arranged in the limiting groove, can not only effectively prevent the sealing strip from being misplaced during the pressing process, but also help to ensure the sealing performance, and help to ensure the ridge-to-ridge contact area, thereby reducing the contact resistance, and thus ensuring the performance of the fuel cell stack; at the same time, during the assembly process, the sealing strip can also be quickly installed in the limiting groove, which can improve the assembly efficiency.

[0019] In addition, by making the sealing strip include an abutting portion and a protruding portion, and the width of the protruding portion is smaller than the width of the abutting portion, the sealing strip and the bipolar plate can have a larger contact area, which can increase the sealing reliability; and the protruding portion is inserted into the limiting groove, which can make the protruding portion fit tightly with the limiting groove, which can ensure the stability of the seal. At the same time, the protruding portion can also compensate for the gap change between the membrane electrode frame and the bipolar plate to a certain extent, further improving the sealing performance.

[0020] Secondly, setting the protruding portion in the middle of the abutting portion in the width direction helps the sealing strip to evenly transfer the pressure to the contact surface between the protruding portion and the limiting groove when it is subjected to pressure from the bipolar plate, thereby ensuring the stability of the seal; and by limiting the relationship between the width of the limiting groove and the width of the protruding portion to K=L+(0.08~0.1)mm, the tolerance of the sealing strip can be fully considered while meeting the sealing performance, thereby improving the assembly efficiency.

[0021] Furthermore, by providing a sealing groove on the bipolar plate, a stable installation position can be provided for the sealing strip, thereby effectively preventing the sealing strip from shifting or deforming. By abutting the side walls of the sealing groove on both sides of the abutting portion in the width direction, the sealing effect between the sealing strip and the bipolar plate can be improved, thereby preventing the fuel gas and oxidant from leaking in the gap between the membrane electrode frame and the bipolar plate.

[0022] Setting the cross-sections of the abutting portion and the protruding portion into a rectangle can ensure a larger contact area between the abutting portion and the bipolar plate, and between the protruding portion and the frame of the membrane electrode, thereby improving the sealing reliability; and by providing ribs on the protruding portion, when the bipolar plate and the frame of the membrane electrode squeeze the sealing strip against each other, the ribs are easily deformed, thereby generating reverse pressure, making the sealing strip fit more closely to the sealing surface, thereby effectively preventing the leakage of fuel gas and oxidant.

[0023] In addition, by providing a plurality of ribs spaced apart along the width direction of the protruding portion, each rib can be elastically deformed and provide reverse support force, so that the sealing strip can better fit the sealing surface at different positions and more evenly distribute the pressure, thereby effectively preventing the fuel gas and oxidant from leaking from the gap between the membrane electrode frame and the bipolar plate.

[0024] Another object of the present invention is to provide a single cell, the single cell comprising the fuel cell sealing structure as described above, as well as a bipolar plate and a membrane electrode;

[0025] The anode plate in one bipolar plate, the membrane electrode and the cathode plate in another bipolar plate form the single cell, and the fuel cell sealing structure is arranged between the membrane electrode and the bipolar plate.

[0026] The single cell described in the present invention can effectively prevent the sealing strip from being misplaced during the pressing process by providing the fuel cell sealing structure as described above, thereby ensuring the sealing performance, ensuring the ridge-to-ridge contact area, and reducing the contact resistance, thereby ensuring the performance of the fuel cell stack.

[0027] In addition, the present invention also provides a fuel cell stack, including the fuel cell sealing structure described above.

[0028] At the same time, the present invention also provides a fuel cell system, including the fuel cell sealing structure described above.

[0029] The battery stack and fuel cell system described in the present invention, by providing the fuel cell sealing structure as described above, are conducive to ensuring the ridge-to-ridge contact area and reducing the contact resistance, thereby effectively ensuring the performance of the battery stack and fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 This is a schematic structural diagram of a fuel cell sealing structure according to an embodiment of the present utility model;

[0032] Figure 2 This is a diagram of the assembly state of the frame and sealing strip of the membrane electrode according to an embodiment of the present utility model;

[0033] Figure 3 This is another structural schematic diagram of the sealing strip described in an embodiment of the utility model.

[0034] Description of reference numerals:

[0035] 1. Frame of membrane electrode; 2. Bipolar plate; 3. Sealing strip;

[0036] 101, outer frame; 1011, limiting groove;

[0037] 201, sealing groove;

[0038] 301. Abutting portion; 302. Protruding portion; 303. Raised rib. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0040] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] Furthermore, in the description of this utility model, unless otherwise explicitly defined, the terms "mounted," "connected," "connect," and "connector" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0043] In a proton exchange membrane fuel cell, the sealing between the bipolar plate 2 and the frame 1 of the membrane electrode is crucial. Poor sealing can lead to leakage of fuel gas and oxidant, which not only reduces the performance and efficiency of the battery, but also may pose a safety hazard. A good seal can ensure that the fuel gas and air flow in their respective flow channels without mixing or leaking, thereby ensuring the efficient conduct of the electrochemical reaction. However, in the existing fuel cell stack, the anode strips of the bipolar plate 2, the frame 1 of the membrane electrode, and the cathode strips of the bipolar plate 2 are usually in contact with each other. Therefore, during the press-fitting process of the proton exchange membrane fuel cell, when the bipolar plate 2 slips and dislocates laterally, the relative area of ​​the ridges between the flow channels will decrease, which can easily lead to a reduction in the effective area for gas transmission and reaction. The flow of gas in the flow channel may be hindered, affecting the uniform distribution of the fuel gas and oxidant, thereby reducing the efficiency of the electrochemical reaction.

[0044] To this end, this embodiment specifically proposes a novel fuel cell sealing structure, including a sealing strip 3 disposed between the membrane electrode frame 1 and the bipolar plate 2. The membrane electrode frame 1 is provided with a retaining groove 1011, and at least a portion of the sealing strip 3 is disposed within the retaining groove 1011, thereby sealing the gap between the membrane electrode frame 1 and the bipolar plate 2.

[0045] The fuel cell sealing structure of this embodiment, by providing a retaining groove 1011 on the membrane electrode dividing frame and positioning at least a portion of the sealing strip 3 within the retaining groove 1011, effectively prevents the sealing strip 3 from being misaligned during press-fitting, thereby ensuring sealing performance and ridge-to-ridge contact area, thereby reducing contact resistance and ensuring fuel cell stack performance. Furthermore, during assembly, the sealing strip 3 can be quickly installed within the retaining groove 1011, thereby improving assembly efficiency.

[0046] Based on the above overall introduction, an exemplary structure of the fuel cell sealing structure of this embodiment is as follows: Figure 1 As shown in , and, to clearly illustrate the improvements of this embodiment, Figure 1 The layout structure of the fuel cell sealing structure is only shown in FIG. Figure 1 and Figure 2 As shown in , the frame 1 of the membrane electrode of this embodiment includes a frame body and outer frames 101 provided on two opposite sides of the frame body. Similar to the prior art, the frame body is used to cooperate with the proton exchange membrane and the catalyst layer, while the outer frame 101 is used to constrain the gas diffusion layer and to contact the bipolar plate 2. Therefore, the above-mentioned limiting grooves 1011 are specifically provided on the outer frame 101.

[0047] In addition, as a specific embodiment, Figure 1 and Figure 2 As shown in , the frame body of this embodiment is a double-layer frame to have good structural strength. Its specific structure can refer to the existing technology. Of course, it is also feasible for the frame body to be a single-layer frame. In addition, since the core components of the proton exchange membrane fuel cell stack are the membrane electrode and the bipolar plate 2, the stack is composed of multiple bipolar plates 2 and membrane electrodes stacked on each other. For this reason, as a preferred embodiment, Figure 1 As shown in FIG, limiting grooves 1011 are provided on both sides of the membrane electrode frame 1 to ensure a good sealing effect between the membrane electrode frame 1 and the bipolar plates 2 on both sides. However, it should be noted that it is also feasible to provide the limiting groove 1011 on only one side of the membrane electrode frame 1.

[0048] Combine Figures 1 to 2 As shown in , as a preferred embodiment, the sealing strip 3 of this embodiment includes an abutting portion 301 that abuts the bipolar plate 2, and a protruding portion 302 that protrudes toward the side of the frame 1 of the membrane electrode. In addition, the width of the protruding portion 302 is smaller than the width of the abutting portion 301, and the protruding portion 302 is inserted into the limiting groove 1011. Such a configuration allows the abutting portion 301 to provide a wider sealing area when in contact with the bipolar plate 2 due to its relatively large width, thereby enhancing the sealing effect. Even if there is a certain degree of unevenness on the surface of the bipolar plate 2, it can better adapt to and maintain the seal, which can effectively prevent gas leakage from the contact surface between the abutting portion 301 and the bipolar plate 2.

[0049] At the same time, it also facilitates the smooth insertion of the protruding portion 302 into the limiting groove 1011, ensuring the convenience and accuracy of installation, and can also limit the lateral movement of the sealing strip 3, ensuring the stability of its position. In addition, after installation is completed, the close contact between the abutting portion 301 and the bipolar plate 2, and the fixation of the protruding portion 302 in the limiting groove 1011, enable the sealing strip 3 to withstand certain external forces such as pressure and vibration during the operation of the fuel cell without being easily displaced or deformed, thereby ensuring the long-term stability of the sealing structure. In addition, the protruding portion 302 can also compensate for the gap changes between the frame 1 of the membrane electrode and the bipolar plate 2 to a certain extent, further improving the sealing performance.

[0050] As a further embodiment, Figure 1 and Figure 2 As shown in , the protrusion 302 is located in the middle of the width of the abutting portion 301, and the width K of the limiting groove 1011 and the width L of the protrusion 302 satisfy the following relationship: K = L + (0.08-0.1) mm. In this embodiment, by locating the protrusion 302 in the middle of the width of the abutting portion 301, when the bipolar plate 2 and the membrane electrode frame apply pressure to the sealing strip 3, the central protrusion 302 can more evenly distribute the pressure on the abutting portion 301 and the entire sealing structure.

[0051] Furthermore, during installation, the central location of protrusion 302 makes it easier to align sealing strip 3 with retaining groove 1011, improving installation efficiency. Furthermore, by defining the relationship between the width of retaining groove 1011 and the width of protrusion 302 as K = L + (0.08-0.1) mm, the tolerance of sealing strip 3 can be fully accounted for while ensuring sealing performance, thereby improving assembly efficiency. In specific implementations, K can be set to L + 0.08 mm, or K = L + 0.09 mm, or other relationships between K and L can be established.

[0052] like Figure 1 As shown in , as a preferred embodiment, a sealing groove 201 is provided on the bipolar plate 2, and a sealing strip 3 is provided in the sealing groove 201, with both sides of the abutting portion 301 in abutment with the side walls of the sealing groove 201 in the width direction. In this embodiment, by providing the sealing groove 201 on the bipolar plate 2, a stable installation position is provided for the sealing strip 3, thereby effectively preventing the sealing strip 3 from shifting or deforming, and facilitating the stability of the seal. Furthermore, by abutting both sides of the abutting portion 301 in the width direction with the side walls of the sealing groove 201, the sealing effect between the sealing strip 3 and the bipolar plate 2 is improved, thereby preventing the fuel gas and oxidant from leaking in the gap between the membrane electrode frame and the bipolar plate 2.

[0053] Furthermore, during installation, the sealing groove 201 provides a clear installation location for the sealing strip 3, allowing the operator to easily place the sealing strip 3 into the sealing groove 201. Furthermore, installation is accomplished through the natural abutment between the abutting portion 301 and the sidewall of the sealing groove 201, eliminating the need for complex positioning and adjustment operations and improving installation efficiency.

[0054] In addition, as a preferred embodiment, Figure 1 and Figure 2As shown in , the cross-sections of the abutting portion 301 and the protruding portion 302 of this embodiment are rectangular. The advantage of this design is that it can provide a larger contact area between the abutting portion 301 and the bipolar plate 2, as well as between the protruding portion 302 and the frame 1 of the membrane electrode, which can more evenly distribute the pressure and better resist the penetration of gas through tiny gaps, thereby improving the sealing reliability. In addition, the rectangular structure itself has a certain stability, which can prevent the abutting portion 301 and the protruding portion 302 from being easily twisted or deformed when subjected to vibration or pressure shock, thereby further ensuring the integrity and stability of the sealing structure.

[0055] It should be noted that the cross-sections of the abutting portion 301 and the protruding portion 302 are both rectangular, but they can also be configured in different shapes. For example, the cross-section of the abutting portion 301 can be rectangular, while the cross-section of the protruding portion 302 can be semicircular, or other shapes can also be configured.

[0056] In addition, if Figure 3 As shown in , to achieve a better sealing effect, as a further embodiment, a rib 303 is provided on the side of the protruding portion 302 facing away from the abutting portion 301. The rib 303 extends along the length of the protruding portion 302. In this embodiment, by providing the rib 303 on the protruding portion 302, when the bipolar plate 2 and the frame 1 of the membrane electrode press against the sealing strip 3, the rib 303 is easily deformed, thereby generating reverse pressure, causing the sealing strip 3 to adhere more tightly to the sealing surface, thereby effectively preventing leakage of fuel gas and oxidant.

[0057] Furthermore, as a further embodiment, the ribs 303 are multiple and spaced apart along the width direction of the protruding portion 302. As a specific embodiment, Figure 3 As shown in , in this embodiment, three ribs 303 are spaced apart along the width of the protruding portion 302. Of course, the number of ribs 303 can be adjusted according to specific circumstances. In this embodiment, by providing multiple ribs 303 spaced apart along the width of the protruding portion 302, each rib 303 can be elastically deformed and provide a reverse support force. This allows the sealing strip 3 to better conform to the sealing surface at different positions, more evenly distributing the pressure applied to it, and effectively preventing the leakage of fuel gas and oxidant from the gap between the membrane electrode frame and the bipolar plate 2.

[0058] Moreover, even if there are some irregularities in the sealing surface between the protruding portion 302 and the frame 1 of the membrane electrode, the multiple ribs 303 can adapt to and fit tightly to the frame 1 of the membrane electrode through their own elastic deformation, effectively reducing the possibility of gas leakage and improving the sealing performance.

[0059] Finally, it should be noted that, in addition to having part of the sealing strip 3 located in the limiting groove 1011 of the frame 1 of the membrane electrode, the entire sealing strip 3 can also be located in the limiting groove 1011. In this case, in order to ensure the sealing effect, a protrusion can be provided on the bipolar plate 2 to be inserted into the limiting groove 1011 and abut against the protruding portion 302. In addition, the structure of the sealing strip 3 is not limited to Figure 1 The T-shape shown in FIG can also be set to a rectangular, circular or other shape.

[0060] The fuel cell sealing structure of this embodiment, by adopting the above structure, not only achieves a good sealing effect, but also significantly alleviates stack misalignment, reduces the insulation risk of the entire stack, ensures ridge-to-ridge contact area, reduces contact resistance, and ensures stack performance. Furthermore, during the assembly process, the sealing strip 3 can be quickly installed into the limiting groove 1011, which can improve assembly efficiency.

[0061] Furthermore, this embodiment also relates to a single cell comprising the fuel cell sealing structure described above, as well as bipolar plates and membrane electrode systems. The anode plate and membrane electrode system in one bipolar plate, along with the cathode plate in another bipolar plate, form the single cell, with the fuel cell sealing structure disposed between the membrane electrode system and the bipolar plates.

[0062] The fuel cell of this embodiment can effectively prevent the sealing strip 3 from being misplaced during the press-fitting process by providing the fuel cell sealing structure as described above, thereby ensuring the sealing performance, ensuring the ridge-to-ridge contact area, and reducing the contact resistance, thereby ensuring the performance of the fuel cell stack.

[0063] In addition, this embodiment also provides a fuel cell stack, including the fuel cell sealing structure described above.

[0064] At the same time, this embodiment also provides a fuel cell system, including the fuel cell sealing structure described above.

[0065] The battery stack and fuel cell system described in this embodiment, by providing the fuel cell sealing structure as described above, is conducive to ensuring the ridge-to-ridge contact area and reducing the contact resistance, thereby effectively ensuring the performance of the battery stack and fuel cell system.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fuel cell sealing structure, characterized in that: It comprises a sealing strip (3) provided between a frame (1) of a membrane electrode and a bipolar plate (2); A limiting groove (1011) is provided on the frame (1) of the membrane electrode, and at least part of the sealing strip (3) is provided in the limiting groove (1011) and is used to seal the gap between the frame (1) of the membrane electrode and the bipolar plate (2).

2. The fuel cell sealing structure according to claim 1, wherein: The sealing strip (3) comprises a contact portion (301) contacting the bipolar plate (2), and a protruding portion (302) protruding toward one side of the frame (1) of the membrane electrode; The width of the protruding portion (302) is smaller than the width of the abutting portion (301), and the protruding portion (302) is inserted into the limiting groove (1011).

3. The fuel cell sealing structure according to claim 2, wherein: The protruding portion (302) is located in the middle of the abutting portion (301) in the width direction, and the width K of the limiting groove (1011) and the width L of the protruding portion (302) satisfy: K=L+(0.08-0.1) mm.

4. The fuel cell sealing structure according to claim 2, wherein: A sealing groove (201) is provided on the bipolar plate (2), the sealing strip (3) is provided in the sealing groove (201), and both sides of the abutting portion (301) in the width direction abut against the side walls of the sealing groove (201).

5. The fuel cell sealing structure according to claim 2, wherein: The cross-sections of the abutting portion (301) and the protruding portion (302) are both rectangular; and / or, A convex rib (303) is provided on a side of the protruding portion (302) away from the abutting portion (301), and the convex rib (303) extends along the length direction of the protruding portion (302).

6. The fuel cell sealing structure according to claim 5, characterized in that: The convex ribs (303) are multiple and spaced apart along the width direction of the protruding portion (302).

7. The fuel cell sealing structure according to any one of claims 1 to 6, characterized in that: The membrane electrode frame (1) comprises a frame body and outer frames (101) arranged on two opposite sides of the frame body; The outer frame (101) is used to constrain the gas diffusion layer, and the limiting groove (1011) is provided on the outer frame (101).

8. A single battery, characterized in that: The single cell comprises the fuel cell sealing structure according to any one of claims 1 to 7, as well as a bipolar plate and a membrane electrode; The anode plate in one bipolar plate, the membrane electrode and the cathode plate in another bipolar plate form the single cell, and the fuel cell sealing structure is arranged between the membrane electrode and the bipolar plate.

9. A fuel cell stack, characterized in that: A fuel cell sealing structure comprising the fuel cell sealing structure according to any one of claims 1 to 7.

10. A fuel cell system, characterized in that: A fuel cell sealing structure comprising the fuel cell sealing structure according to any one of claims 1 to 7.

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