Bipolar plate assembly and fuel cell

Abstract

The utility model relates to the technical field of fuel cells, in particular to a bipolar plate assembly and a fuel cell. The bipolar plate assembly comprises a first electrode plate and a second electrode plate, first sealing protruding parts are arranged on the outer edge and the cavity opening of the first electrode plate, and second sealing protruding parts are arranged on the outer edge and the cavity opening of the second electrode plate. In the thickness direction, the first electrode plate and the second electrode plate are arranged in a stacked mode, notches of the first sealing protruding part and the second sealing protruding part are oppositely arranged and form a containing cavity, and a supporting piece is arranged in the containing cavity. The protruding end of the first sealing protruding part and the protruding end of the second sealing protruding part are oppositely arranged, so that the first sealing protruding part and the second sealing protruding part form a hard sealing structure, and the durability of the sealing structure is improved. Meanwhile, a supporting piece is further arranged between the first sealing protruding part and the second sealing protruding part, the supporting effect on the first sealing protruding part and the second sealing protruding part is achieved, the risk of deformation of the first sealing protruding part and the second sealing protruding part is reduced, and the sealing effectiveness of the sealing structure is improved.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cells, and in particular to a bipolar plate assembly and a fuel cell. Background Art

[0002] Fuel cells output energy through redox reactions on the positive and negative sides of the proton membrane (usually presented by the membrane electrode assembly), and the plates provide independent circulation places and effective separation support for the raw materials and coolant of the redox reaction. The membrane electrode assembly and the plates cooperate with each other to form a fuel cell, and neither is indispensable.

[0003] The sealing structure of conventional fuel cell bipolar plates is generally composed of a seal made of rubber material placed in a bipolar plate sealing groove, which needs to be prepared by bonding prefabricated seals with room temperature curing adhesives or directly injecting seals after primer coating with hot vulcanized adhesives. This involves the material development of adhesives and seals, as well as the coating process of adhesives and the vulcanization process of seals.

[0004] For the traditional fuel cell bipolar plate structure type, the material selection involves the rotation of at least two types of materials (sealing materials and adhesives), and the above materials are exposed to the use environment for a long time, directly contacting the combined effects of acid, heat, mechanical and other factors, and the durability research is complicated. In manufacturing, there are adhesives and seals on both sides of the plate. When manufacturing seals, due to the characteristics of the material, the vulcanization time of the seals is long, the manufacturing cycle is long, and the precision requirements for the seals are high, and the mold and tooling costs are high. When the seals and substrates are bonded by adhesives, the adhesive needs to be coated twice, the process is complicated, and the coating precision requirements are high, and the equipment and tooling costs are high. To achieve long-term effective and stable operation, it is necessary to conduct rigorous durability tests on the materials. To ensure the complex process and high precision requirements of the manufacturing process, it is necessary to pay high manufacturing costs, which is not conducive to the process of large-scale industrialization. Utility Model Content

[0005] The present application provides a bipolar plate assembly and a fuel cell, which aim to improve the sealing stability of the bipolar plate while improving the preparation efficiency.

[0006] The present application provides a bipolar plate assembly, the bipolar plate assembly comprising:

[0007] A first electrode plate, wherein a first sealing protrusion is provided at the outer edge and the cavity opening of the first electrode plate;

[0008] A second electrode plate, wherein a second sealing protrusion is provided at the outer edge and the cavity opening of the second electrode plate;

[0009] The first electrode plate and the second electrode plate are stacked along the thickness direction of the bipolar plate assembly, and the first sealing protrusion and the second sealing protrusion have recesses that are opposite to each other and form a receiving cavity, in which a support member is disposed.

[0010] In a possible design, along the length direction of the bipolar plate assembly, a first injection hole is provided on the outer side of the first sealing protrusion, and a second injection hole is provided on the outer side of the second sealing protrusion;

[0011] The first injection hole and the second injection hole are used to inject the injection material into the accommodating cavity to form the support member in the accommodating cavity.

[0012] In a possible design, the support member includes a first support portion and a second support portion;

[0013] The first supporting portion is disposed in a first groove formed by the first sealing protrusion, and the second supporting portion is disposed in a second groove formed by the second sealing protrusion;

[0014] The first groove and the second groove are combined to form the accommodating cavity.

[0015] In a possible design, the first electrode plate includes a first flow channel, the first flow channel is connected to the corresponding cavity port, and the first sealing protrusion located at the cavity port and the support member inside are provided with a first avoidance channel connected to the first flow channel;

[0016] The second electrode plate includes a second flow channel, which is communicated with the corresponding cavity opening. The second sealing protrusion located at the cavity opening and the support member inside are provided with a second avoidance channel communicated with the second flow channel.

[0017] In a possible design, the depth of the first flow channel is d1, the height of the first sealing protrusion is h1, and d1 and h1 satisfy: 30%≤d1 / h1≤99%;

[0018] The depth of the second flow channel is d2, the height of the second sealing protrusion is h2, and d2 and h2 satisfy: 30%≤d2 / h2≤99%.

[0019] In a possible design, the first electrode plate and the second electrode plate are welded and fixed, and a plurality of welding positions are provided on the two.

[0020] The welding position includes a first welding position and a second welding position, wherein the first welding position is arranged at the outer edge of the first electrode plate and the second electrode plate and is located outside the support member;

[0021] The second welding position is arranged at the periphery of the air cavity opening of the first electrode plate and the air cavity opening of the second electrode plate.

[0022] In a possible design, the welding position further includes a third welding position, and the third welding position is arranged at the outer edges of the first electrode plate and the second electrode plate, and is arranged on the inner side of the support member;

[0023] Part of the third welding position located at the periphery of the air cavity opening overlaps with part of the second welding position.

[0024] In a possible design, the first electrode plate further includes a first elastic sealing portion, and the first elastic sealing portion is arranged at a raised end of the first sealing raised portion;

[0025] The second electrode plate includes a second elastic sealing portion, and the second elastic sealing portion is disposed at a protruding end of the second sealing protrusion.

[0026] In a possible design, the material of the support member may be one of polysulfone, polyetherimide, polyphenylene sulfide, polyamide, and polypropylene.

[0027] The present application also provides a fuel cell, the fuel cell comprising:

[0028] Membrane electrode assembly;

[0029] A bipolar plate assembly, wherein the bipolar plate assembly is the bipolar plate assembly described above, and the bipolar plate assembly is stacked with the membrane electrode assembly.

[0030] In a possible design, the height of the first sealing protrusion is h1, the height of the second sealing protrusion is h2, the height of the proton membrane is h3, the height of the diffusion layer is h4, the height of the flow field area is h5, and the thickness of the proton membrane frame is h6;

[0031] Among them, h1=h3 / 2+h4+h5-h6 / 2; h2=h3 / 2+h4+h5-h6 / 2.

[0032] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of a bipolar plate for a fuel cell in the prior art;

[0034] Figure 2 A schematic diagram of a production process of bonding a prefabricated seal to a bipolar plate of a fuel cell by a room temperature curing adhesive in the prior art;

[0035] Figure 3It is a schematic diagram of the production process of a fuel cell bipolar plate in the prior art, in which a seal is directly injection molded after a base coat of a hot-vulcanized adhesive is applied;

[0036] Figure 4 A schematic structural diagram of a monopolar plate formed by stamping a bipolar plate for a fuel cell provided in the present application in one embodiment;

[0037] Figure 5 This is a schematic diagram of the structure of the support member provided in this application;

[0038] Figure 6 A cross-sectional schematic diagram of the bipolar plate sealing structure provided in the present application in cooperation with other components in one embodiment;

[0039] Figure 7 A schematic structural diagram of another embodiment of a monopolar plate formed by stamping a bipolar plate for a fuel cell provided in the present application;

[0040] Figure 8 A schematic diagram of a welding position of a bipolar plate provided in the present application in one embodiment;

[0041] Fig. 9 A schematic diagram of a welding position of a bipolar plate provided in the present application in another embodiment;

[0042] Fig.10 A partial structural schematic diagram of the monopolar plate provided in this application;

[0043] Fig.11 A cross-sectional schematic diagram of another embodiment of the bipolar plate sealing structure provided in the present application in cooperation with other components;

[0044] Fig.12 A schematic diagram of the connection between the plate flow channel structure and the cavity provided in this application;

[0045] Fig.13 This is a schematic diagram of the first avoidance channel on the first sealing protrusion provided in the present application.

[0046] Reference numerals:

[0047] 1′- cathode monopolar plate;

[0048] 2′- anode monopolar plate;

[0049] 3′- cathode seal;

[0050] 4′- anode seal;

[0051] 1- first electrode plate;

[0052] 11- first sealing protrusion;

[0053] 111-first injection hole;

[0054] 112-First avoidance channel;

[0055] 12- first flow channel;

[0056] 13- first welding position;

[0057] 14- second welding position;

[0058] 15-the third welding position;

[0059] 16-first elastic sealing portion;

[0060] 2- second electrode plate;

[0061] 21- second sealing protrusion;

[0062] 211- second injection hole;

[0063] 212-Second avoidance channel;

[0064] 22- second flow channel;

[0065] 23-accommodating chamber;

[0066] 24- second elastic sealing portion;

[0067] 3- Support member;

[0068] 4-Membrane electrode assembly.

[0069] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0070] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0071] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0072] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0073] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0074] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0075] At present, the common fuel cell structures are bipolar plate structure and integrated structure. Among them, the bipolar plate structure is connected by welding the positive and negative monopolar plates, and then connected to the cathode seal and the anode seal through adhesives, and is assembled and used in conjunction with the membrane electrode assembly during the assembly process.

[0076] like Figure 1 The sealing structure of a prior art fuel cell is shown, including a cathode monopolar plate 1', an anode monopolar plate 2', a cathode seal 3' and an anode seal 4'. A cathode sealing groove is provided on the side of the cathode monopolar plate 1' facing away from the anode monopolar plate 2', and the cathode seal 3' is provided in the cathode sealing groove. An anode sealing groove is provided on the side of the anode monopolar plate 2' facing away from the cathode monopolar plate 1', and the anode seal 4' is provided in the anode sealing groove.

[0077] The cathode seal 3' and the anode seal 4' are generally made of rubber material. Figure 2 and Figure 3 Shown is a schematic diagram of the process of preparing seals to bipolar plates.

[0078] Specifically, if Figure 2 As shown, the cathode seal 3' and the anode seal 4' are first prefabricated, and the cathode monopolar plate 1' and the anode monopolar plate 2' are welded at the same time, and then glue is applied in the cathode sealing groove and the anode sealing groove, and finally the cathode seal 3' is bonded to the cathode sealing groove, and the anode seal 4' is bonded to the anode sealing groove.

[0079] like Figure 3 As shown, the cathode monopolar plate 1' and the anode monopolar plate 2' are first welded, then adhesive is applied to the cathode sealing groove and the anode sealing groove, and injection molding material is injected into the cathode sealing groove and the anode sealing groove to form the cathode sealing member 3' and the anode sealing member 4'.

[0080] In the above-mentioned prior art bipolar plate and seal structure and preparation method, the adhesive and sealing material will be exposed to the use environment for a long time, directly contacting acid, heat, mechanical external force, etc., and have poor durability. When preparing the seal, due to the material characteristics, the vulcanization time of the seal is long, the manufacturing cycle is long, and the precision requirements for the seal are high, and the mold and tooling costs are high.

[0081] To this end, this embodiment provides a fuel cell to solve the above technical problems.

[0082] The fuel cell includes a membrane electrode assembly and a bipolar plate assembly, which are stacked with the membrane electrode assembly. The membrane electrode is composed of a diffusion layer, a catalyst layer and a proton membrane, and energy is output through a redox reaction on the positive and negative sides of the proton membrane. The main functions of the bipolar plate are to support the membrane electrode assembly, provide hydrogen, oxygen and coolant fluid channels and separate hydrogen and oxygen, collect electrons, conduct heat, etc.

[0083] The structure of the bipolar plate assembly is described in detail below with reference to the accompanying drawings.

[0084] like Figure 4 The schematic diagram of the first electrode plate 1 (the second electrode plate 2) is shown as follows. Figure 5 Shown is a schematic diagram of the support member 3, as shown in Figure 6 The figure shows a cross-sectional schematic diagram of the bipolar plate assembly and the membrane electrode assembly 4 when they are matched. Figures 4 to 6 The bipolar plate assembly includes a first electrode plate 1 and a second electrode plate 2. A first sealing protrusion 11 is provided at the outer edge and the cavity position of the first electrode plate 1, and a second sealing protrusion 21 is provided at the outer edge and the cavity position of the second electrode plate 2. Along the thickness direction of the bipolar plate assembly, the first electrode plate 1 and the second electrode plate 2 are stacked, and the first sealing protrusion 11 and the second sealing protrusion 21 are arranged opposite to each other to form a receiving cavity 23, and a support member 3 is arranged in the receiving cavity 23.

[0085] In this embodiment, by forming a first sealing protrusion 11 on the first electrode plate 1 and forming a second sealing protrusion 21 on the second electrode plate 2, after the second electrode plate 2 is connected, the protrusion end of the first sealing protrusion 11 and the protrusion end of the second sealing protrusion 21 are arranged opposite to each other, so that the two form a hard sealing structure, thereby improving the durability of the sealing structure. In addition, the first sealing protrusion 11 and the second sealing protrusion 21 are directly formed by a stamping process, thereby reducing the preparation process of the sealing structure and improving the preparation efficiency. The first sealing protrusion 11 and the second sealing protrusion 21 bite the frame of the membrane electrode assembly 4 to ensure the sealing between the membrane electrode assembly 4 and the bipolar plate.

[0086] In addition, a support member 3 is provided between the first sealing protrusion 11 and the second sealing protrusion 21. The support member 3 can support the first sealing protrusion 11 and the second sealing protrusion 21, reduce the risk of deformation of the first sealing protrusion 11 and the second sealing protrusion 21, thereby reducing the risk of gas leakage caused by compression deformation of the sealing structure, increase the effectiveness of the sealing structure, and ensure the stability of the bipolar plate assembly during long-term use.

[0087] like Figure 7 It is a schematic diagram of the first electrode plate 1 (the second electrode plate 2 ). In some embodiments, the first sealing protrusion 11 on the periphery of the water cavity can be combined with the first sealing protrusion 11 on the outer edge of the electrode plate.

[0088] The height of the first sealing protrusion 11 is h1, the height of the second sealing protrusion 21 is h2, the height of the proton membrane is h3, the height of the diffusion layer is h4, the height of the flow field area is h5, and the thickness of the proton membrane frame is h6. Among them, h1 = h3 / 2 + h4 + h5 - h6 / 2; h2 = h3 / 2 + h4 + h5 - h6 / 2.

[0089] In this embodiment, by limiting the height of the first sealing protrusion 11 and the second sealing protrusion 21 , the first sealing protrusion 11 and the second sealing protrusion 21 can be closely contacted with the two end surfaces of the proton membrane frame respectively, thereby ensuring the sealing effect.

[0090] Furthermore, the material of the support member 3 can be polysulfone, polyetherimide, polyphenylene sulfide, polyamide, polypropylene, etc. The support member 3 only bears the mechanical support function and does not bear the direct sealing function. Therefore, the material requirements for the support member 3 are relatively low, and the material can be selected from a wide range, which can effectively reduce the material cost of the bipolar plate sealing structure. In addition, the curing time of the support member 3 using the above material is also short, which improves the preparation efficiency, thereby improving the manufacturing efficiency of the sealing structure of the bipolar plate assembly.

[0091] like Figure 8 The figure shows a schematic diagram of welding the first electrode plate 1 and the second electrode plate 2. Due to the low material performance of the support member 3, the bonding performance of the support member 3 to the first electrode plate 1 and the second electrode plate 2 cannot achieve a fixed connection between the two. To this end, the first electrode plate 1 and the second electrode plate 2 can be fixed by welding, and the two are provided with multiple welding positions.

[0092] Specifically, the welding position includes a first welding position 13 and a second welding position 14. The first welding position 13 is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is located outside the support member 3. The first welding position 13 mainly serves to fix the first electrode plate 1 and the second electrode plate 2, and also limits the gas from leaking out through the matching position of the first sealing protrusion 11 and the second sealing protrusion 21.

[0093] The second welding position 14 is arranged at the periphery of the gas cavity opening of the first electrode plate 1 and the gas cavity opening of the second electrode plate 2, and the second welding position 14 surrounds the first sealing protrusion 11 and the second sealing protrusion 21 located at the gas cavity opening. The second welding position 14 is specifically arranged at the periphery of the inlet hydrogen cavity opening, the inlet oxygen cavity opening, the outlet hydrogen cavity opening and the outlet oxygen cavity opening, so as to fix the first electrode plate 1 and the second electrode plate 2 while limiting the gas flow, reducing the corrosion of the electrode plates and extending the service life of the electrode plates.

[0094] Furthermore, the welding position also includes a third welding position 15, which is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is arranged on the inner side of the support member 3. Part of the third welding position 15 located at the outer periphery of the gas cavity opening overlaps part of the second welding position 14. In this embodiment, by setting the third welding position 15, the gas is restricted from flowing to the edge of the plate, the corrosion of the plate is reduced, and the service life of the plate is extended.

[0095] like Figure 8 Shown Figure 7 Schematic diagram of welding the first electrode plate 1 and the second electrode plate 2, corresponding to Figure 7 As shown in the distribution of the first sealing protrusion 11 and the second sealing protrusion 21, no welding line is provided at the merging position of the first sealing protrusion 11 on the outer periphery of the water cavity and the first sealing protrusion 11 on the outer plate of the electrode plate.

[0096] In some embodiments, the first electrode plate 1 and the second electrode plate 2 are fixed by welding, and the support member 3 can be prepared in the accommodating cavity 23 after welding, or can be prepared in the accommodating cavity 23 before welding.

[0097] like Fig.10 The figure shows an enlarged schematic diagram of the first sealing protrusion 11 (the second sealing protrusion 21). Specifically, along the length direction of the bipolar plate assembly, a first injection hole 111 is provided on the outside of the first sealing protrusion 11, and a second injection hole 211 is provided on the outside of the second sealing protrusion 21. After the first electrode plate 1 and the second electrode plate 2 are welded to form a bipolar plate, the first sealing protrusion 11 and the second sealing protrusion 21 have recesses that relatively surround a receiving cavity 23, and the injection material can be injected into the receiving cavity 23 through the first injection hole 111 and the second injection hole 211 to form a support member 3 in the receiving cavity 23, thereby forming a bipolar plate assembly.

[0098] The first injection hole 111 is arranged outside the first sealing protrusion 11, and the second injection hole 211 is arranged outside the second sealing protrusion 21, so as to facilitate injection molding. In addition, the height of the first injection hole 111 is less than the height of the first sealing protrusion 11, and the height of the second injection hole 211 is less than the height of the second sealing protrusion 21, so as to prevent the injection material from flowing out.

[0099] Alternatively, since the first electrode plate 1 is punched to form the first sealing protrusion 11 and the first groove is formed at the same time, and the second electrode plate 2 is punched to form the second sealing protrusion 21 and the second groove is formed at the same time, the injection molding material can be first injected into the first groove to form the first support portion, and the injection molding material can be injected into the second groove to form the second support portion. Then, the first electrode plate 1 and the second electrode plate 2 are stacked and arranged, so that the first groove and the second groove are combined to form the accommodating cavity 23, and the first support portion and the second support portion are abutted to form the support member 3. Finally, the first electrode plate 1 and the second electrode plate 2 are welded to form a bipolar plate assembly.

[0100] Before injection molding in the first groove and the second groove, a layer of reactive adhesive can be applied to the inner sidewalls of the first groove and the second groove to bond the first support part to the first groove and the second support part to the second groove. The reactive adhesive can be silane coupling agent, Chemlok, etc.

[0101] Alternatively, the support member 3 can be prefabricated first, and then part of the structure of the support member 3 can be placed in the first groove formed by the first sealing protrusion 11, and finally the first electrode plate 1 and the second electrode plate 2 can be stacked so that the remaining structure of the support member 3 is arranged in the second groove formed by the second sealing protrusion 21, and the first electrode plate 1 and the second electrode plate 2 are welded to form a bipolar plate assembly.

[0102] like Fig.11 The figure shows a cross-sectional schematic diagram of the bipolar plate assembly and the membrane electrode assembly 4 when they are matched. In some embodiments, the first electrode plate 1 further includes a first elastic sealing portion 16, which is disposed at the protruding end of the first sealing protrusion 11. The second electrode plate 2 includes a second elastic sealing portion 24, which is disposed at the protruding end of the second sealing protrusion 21.

[0103] In this embodiment, in order to further improve the sealing effect of the bipolar plate assembly, a first elastic sealing portion 16 can be set at the raised end of the first sealing protrusion 11, and a second elastic sealing portion 24 can be set at the raised end of the second sealing protrusion 21, so that the first elastic sealing portion 16 further seals the joint surface between the first sealing protrusion 11 and the proton membrane frame, and the second elastic sealing portion 24 further seals the joint surface between the second sealing protrusion 21 and the proton membrane frame, thereby further reducing the risk of gas leakage.

[0104] The first elastic sealing portion 16 can be formed by spraying a coating on the protruding end of the first sealing protrusion 11, and the second elastic sealing portion 24 can be formed by spraying a coating on the protruding end of the second sealing protrusion 21. The materials of the first elastic sealing portion 16 and the second elastic sealing portion 24 can be made of materials with superelastic properties such as silicone, fluorine rubber, and EPDM.

[0105] like Fig.12It is a schematic diagram of the connection between the plate flow channel structure and the cavity, such as Fig.13 For a schematic diagram showing the first avoidance passage 112 (the second avoidance passage 212), please refer to Fig.12 and Fig.13 In some embodiments, the first electrode plate 1 includes a first flow channel 12, the first flow channel 12 is connected to the corresponding cavity opening, and the first sealing protrusion 11 located at the cavity opening and the support member 3 inside are provided with a first avoidance channel 112 connected to the first flow channel 12. That is, the first flow channel 12 is provided on one side of each cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) of the first electrode plate 1, the first flow channel 12 is arranged to intersect with a part of the structure of the first sealing protrusion 11, the first sealing protrusion 11 located at the periphery of the cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) and the support member 3 inside the first sealing protrusion 11 are provided with the first avoidance channel 112, and the first avoidance channel 112 is connected to the first flow channel 12, so as to realize the connection between the first flow channel 12 and the corresponding cavity opening.

[0106] Among them, one end of the first flow channel 12 close to the flow field is connected to the distribution area in the water cavity, and is connected to the inflow hole of the air cavity electrode plate in the air cavity area.

[0107] The second electrode plate 2 includes a second flow channel 22, which is connected to the corresponding cavity opening, and the second sealing protrusion 21 located at the cavity opening and the support member 3 inside are provided with a second avoidance channel 212 connected to the second flow channel 22. That is, the second flow channel 22 is provided on one side of each cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) of the second electrode plate 2, and the second flow channel 22 is arranged to intersect with a part of the structure of the second sealing protrusion 21, and the second sealing protrusion 21 located at the periphery of the cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) and the support member 3 inside the second sealing protrusion 21 are provided with the second avoidance channel 212, and the second avoidance channel 212 is connected to the second flow channel 22, so that the second flow channel 22 is connected to the corresponding cavity opening.

[0108] Among them, the second flow channel 22 is connected to the distribution area at the water cavity at one end close to the flow field, and is connected to the inflow hole of the air cavity electrode plate in the air cavity area.

[0109] Specifically, the depth of the first flow channel 12 is d1, the height of the first sealing protrusion 11 is h1, and d1 and h1 satisfy: 30%≤d1 / h1≤99%.

[0110] Illustratively, d1 / h1 may be 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, etc.

[0111] In this embodiment, if d1 / h1 is too large (e.g., d1 / h1>99%), the height of the first flow channel 12 is higher than the height of the first sealing protrusion 11, and the first sealing protrusion 11 may not be able to prevent gas leakage. If d1 / h1 is too large (e.g., d1 / h1<30%), the height of the first flow channel 12 is too low, affecting the circulation of gas.

[0112] The depth of the second flow channel 22 is d2, and the height of the second sealing protrusion 21 is h2. d2 and h2 satisfy: 30%≤d2 / h2≤99%.

[0113] Illustratively, d2 / h2 may be 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, etc.

[0114] In this embodiment, if d2 / h2 is too large (e.g., d2 / h2>99%), the height of the first flow channel 12 is higher than the height of the first sealing protrusion 11, and the first sealing protrusion 11 may not be able to prevent gas leakage. If d2 / h2 is too large (e.g., d2 / h2<30%), the height of the first flow channel 12 is too low, affecting the circulation of gas.

[0115] In combination with the above structural content, in a specific embodiment, the bipolar plate assembly includes a first electrode plate 1, a support member 3 and a second electrode plate 2. A first sealing protrusion 11 facing the gas field protrusion is provided on the first electrode plate 1, and a second sealing protrusion 21 facing the gas field protrusion is provided on the second electrode plate 2. The first sealing protrusion 11 and the second sealing protrusion 21 are realized by a stamping process. The first sealing protrusion 11 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2. The height of the second sealing protrusion 21 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2.

[0116] The paths of the first sealing protrusion 11 and the second sealing protrusion 21 are completely consistent, and independent fully enclosed structures are formed in the air cavity, the water cavity and the peripheral side. Injection holes (first injection holes 111 / second injection holes 211) are opened on each independent fully enclosed structure. The first injection hole 111 is set at the position where the first sealing protrusion 11 faces the peripheral side, and the height of the first injection hole 111 is half of the first sealing protrusion 11. The second injection hole 211 is set at the position where the second sealing protrusion 21 faces the peripheral side, and the height of the second injection hole 211 is half of the second sealing protrusion 21.

[0117] At the cavity opening, the first sealing protrusion 11 is intersected with the first flow channel 12, the height of the first flow channel 12 is 50% of the height of the first sealing protrusion 11, and the first flow channel 12 is connected to the distribution area at the water cavity near the flow field end, and is connected to the inflow hole of the air cavity electrode plate at the air cavity. The second sealing protrusion 21 is intersected with the second flow channel 22, the height of the second flow channel 22 is 50% of the height of the second sealing protrusion 21, and the second flow channel 22 is connected to the distribution area at the water cavity near the flow field end, and is connected to the inflow hole of the air cavity electrode plate at the air cavity.

[0118] After the first electrode plate 1 and the second electrode plate 2 are stamped, the first electrode plate 1 and the second electrode plate 2 are welded to connect. The two have at least three welding positions, the first welding position 13 is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is located outside the first sealing protrusion 11 and the second sealing protrusion 21, the second welding position 14 is arranged at the periphery of the air cavity opening of the first electrode plate 1 and the air cavity opening of the second electrode plate 2, and the third welding position 15 is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is located inside the first sealing protrusion 11 and the second sealing protrusion 21. Part of the third welding position 15 located at the periphery of the air cavity opening overlaps with part of the second welding position 14 to reduce the welding process.

[0119] After the first electrode plate 1 and the second electrode plate 2 are welded to form a bipolar plate, the injection molding material is injected into the accommodating cavity 23 through the first injection molding hole 111 and the second injection molding hole 211 to form a support member 3. Moreover, before injection molding, an insert having the same size as the opening of the first flow channel 12 is placed in the first sealing protrusion 11. An insert having the same size as the opening of the second flow channel 22 is placed in the second sealing protrusion 21. After injection molding, the insert is removed so that the support member 3 in the first sealing protrusion 11 forms a channel having the same size as the opening of the first flow channel 12, and the support member 3 in the second sealing protrusion 21 forms a channel having the same size as the opening of the second flow channel 22, and finally a bipolar plate assembly is formed. Among them, the material of the support member 3 is polypropylene.

[0120] In another specific embodiment, the bipolar plate assembly includes a first electrode plate 1, a support member 3 and a second electrode plate 2. A first sealing protrusion 11 facing the gas field protrusion is provided on the first electrode plate 1, and a second sealing protrusion 21 facing the gas field protrusion is provided on the second electrode plate 2, and the first sealing protrusion 11 and the second sealing protrusion 21 are realized by a stamping process. The first sealing protrusion 11 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2. The height of the second sealing protrusion 21 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2.

[0121] The paths of the first sealing protrusion 11 and the second sealing protrusion 21 are completely consistent, and independent fully enclosed structures are formed in the air cavity, the water cavity and the peripheral side, and injection holes (first injection holes 111 / second injection holes 211) are opened on each independent fully enclosed structure. Among them, the first sealing protrusion 11 on the periphery of the water cavity can be merged with the first sealing protrusion 11 on the edge of the first electrode plate 1, and the second sealing protrusion 21 on the periphery of the water cavity can be merged with the second sealing protrusion 21 on the edge of the second electrode plate 2. Injection holes (first injection holes 111 / second injection holes 211) are opened on each independent fully enclosed structure. And the first injection hole 111 is set at the position where the first sealing protrusion 11 faces the peripheral side, and the height of the first injection hole 111 is half of the first sealing protrusion 11. The second injection hole 211 is set at the position where the second sealing protrusion 21 faces the peripheral side, and the height of the second injection hole 211 is half of the second sealing protrusion 21.

[0122] At the cavity opening, the first sealing protrusion 11 is arranged to intersect with the first flow channel 12, the height of the first flow channel 12 is 75% of the height of the first sealing protrusion 11, and the first flow channel 12 is connected to the distribution area at the water cavity near the flow field end, and is connected to the air cavity plate inflow hole at the air cavity. The second sealing protrusion 21 is arranged to intersect with the second flow channel 22, the height of the second flow channel 22 is 75% of the height of the second sealing protrusion 21, and the second flow channel 22 is connected to the distribution area at the water cavity near the flow field end, and is connected to the air cavity plate inflow hole at the air cavity.

[0123] After the first electrode plate 1 and the second electrode plate 2 are stamped, a layer of silane coupling agent is coated on the inner sidewalls of the first groove and the second groove, and then the injection molding material is injected into the first groove and the second groove to form the first support part and the second support part. Moreover, before injection molding, an insert having the same size as the opening of the first flow channel 12 is placed in the first sealing protrusion 11. An insert having the same size as the opening of the second flow channel 22 is placed in the second sealing protrusion 21. After injection molding, the insert is taken out, so that the first support part in the first sealing protrusion 11 forms a channel having the same size as the opening of the first flow channel 12, and the second support part in the second sealing protrusion 21 forms a channel having the same size as the opening of the second flow channel 22. Among them, the material of the support member 3 is polysulfone.

[0124] The first electrode plate 1 and the second electrode plate 2 bonded with the support member 3 are connected by welding. Among them, the two have at least three welding positions, the first welding position 13 is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is located outside the first sealing protrusion 11 and the second sealing protrusion 21, the second welding position 14 is arranged at the periphery of the air cavity opening of the first electrode plate 1 and the air cavity opening of the second electrode plate 2, and the third welding position 15 is arranged at the outer edge of the first electrode plate 1 and the second electrode plate 2, and is located inside the first sealing protrusion 11 and the second sealing protrusion 21. Part of the third welding position 15 located at the periphery of the air cavity opening overlaps with part of the second welding position 14 to reduce the welding process. Finally, a bipolar plate assembly is formed.

[0125] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A bipolar plate assembly, characterized in that: The bipolar plate assembly comprises: A first electrode plate (1), wherein a first sealing protrusion (11) is provided at the outer edge and the cavity opening of the first electrode plate (1); A second electrode plate (2), wherein a second sealing protrusion (21) is provided at the outer edge and the cavity opening of the second electrode plate (2); The first electrode plate (1) and the second electrode plate (2) are stacked along the thickness direction of the bipolar plate assembly, and the first sealing protrusion (11) and the second sealing protrusion (21) have recesses arranged opposite to each other to form a receiving cavity (23), wherein a support member (3) is arranged in the receiving cavity (23).

2. The bipolar plate assembly according to claim 1, characterized in that: Along the length direction of the bipolar plate assembly, a first injection hole (111) is provided on the outer side of the first sealing protrusion (11), and a second injection hole (211) is provided on the outer side of the second sealing protrusion (21); The first injection hole (111) and the first injection hole (111) are used to inject the injection material into the accommodating cavity (23) to form the support member (3) in the accommodating cavity (23).

3. The bipolar plate assembly according to claim 1, characterized in that: The support member (3) comprises a first support portion and a second support portion; The first supporting portion is arranged in a first groove formed by the first sealing protrusion (11), and the second supporting portion is arranged in a second groove formed by the second sealing protrusion (21); The first groove and the second groove are combined to form the accommodating cavity (23).

4. The bipolar plate assembly according to claim 1, characterized in that: The first electrode plate (1) comprises a first flow channel (12), the first flow channel (12) is connected to a corresponding cavity opening, and the first sealing protrusion (11) located at the cavity opening and the support member (3) inside are provided with a first avoidance channel (112) connected to the first flow channel (12); The second electrode plate (2) comprises a second flow channel (22), the second flow channel (22) being connected to the corresponding cavity opening, and the second sealing protrusion (21) located at the cavity opening and the support member (3) inside are provided with a second avoidance channel (212) connected to the second flow channel (22).

5. The bipolar plate assembly according to claim 4, characterized in that: The depth of the first flow channel (12) is d1, the height of the first sealing protrusion (11) is h1, and d1 and h1 satisfy: 30%≤d1 / h1≤99%; The depth of the second flow channel (22) is d2, the height of the second sealing protrusion (21) is h2, and d2 and h2 satisfy: 30%≤d2 / h2≤99%.

6. The bipolar plate assembly according to claim 1, characterized in that: The first electrode plate (1) and the second electrode plate (2) are welded and fixed, and a plurality of welding positions are provided on the two. The welding position comprises a first welding position (13) and a second welding position (14); the first welding position (13) is arranged at the outer edges of the first electrode plate (1) and the second electrode plate (2), and is located outside the support member (3); The second welding position (14) is arranged at the periphery of the air cavity opening of the first electrode plate (1) and the air cavity opening of the second electrode plate (2).

7. The bipolar plate assembly according to claim 6, characterized in that: The welding position further comprises a third welding position (15), wherein the third welding position (15) is arranged at the outer edges of the first electrode plate (1) and the second electrode plate (2), and is arranged at the inner side of the support member (3); Part of the third welding position (15) located at the periphery of the air cavity opening overlaps with part of the second welding position (14).

8. The bipolar plate assembly according to any one of claims 1 to 7, characterized in that: The first electrode plate (1) further comprises a first elastic sealing portion (16), wherein the first elastic sealing portion (16) is arranged at a protruding end of the first sealing protruding portion (11); The second electrode plate (2) comprises a second elastic sealing portion (24), and the second elastic sealing portion (24) is arranged at a protruding end of the second sealing protruding portion (21).

9. The bipolar plate assembly according to any one of claims 1 to 7, characterized in that: The material of the support member (3) may be one of polysulfone, polyetherimide, polyphenylene sulfide, polyamide and polypropylene.

10. A fuel cell, characterized in that: The fuel cell comprises: Membrane electrode assembly; A bipolar plate assembly, wherein the bipolar plate assembly is the bipolar plate assembly according to any one of claims 1 to 9, and the bipolar plate assembly is stacked with the membrane electrode assembly.

11. The fuel cell according to claim 10, characterized in that The height of the first sealing protrusion (11) is h1, the height of the second sealing protrusion (21) is h2, the height of the proton membrane is h3, the height of the diffusion layer is h4, the height of the flow field area is h5, and the thickness of the proton membrane frame is h6; Among them, h1=h3 / 2+h4+h5-h6 / 2; h2=h3 / 2+h4+h5-h6 / 2.

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