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 monopolar plate, the outer edge and the cavity opening position of the first monopolar plate are each provided with a first sealing part and a first supporting part, in the thickness direction of the bipolar plate assembly, the first sealing part protrudes in the first direction, and the first supporting part protrudes in the second direction; a second supporting part and a second sealing part are arranged on the outer edge and the cavity opening of the second monopole plate, the second supporting part protrudes towards the first direction, and the second sealing part protrudes towards the second direction in the thickness direction of the bipolar plate assembly; in the thickness direction of the bipolar plate assembly, the first monopolar plate and the second monopolar plate are stacked, and the second supporting part is embedded into a recess formed by the first sealing part and is attached to the first sealing part; the first supporting part is embedded into a recess formed by the second sealing part and is attached to the second sealing part; wherein the first direction is opposite to the second direction.

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 selection of at least two types of materials (sealing materials and adhesives), and the above materials are exposed to the combined effects of acid, heat, mechanical factors, etc. in the use environment for a long time, 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 assembly while improving the preparation efficiency.

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

[0007] A first monopolar plate, wherein the outer edge and the cavity of the first monopolar plate are both provided with a first sealing portion and a first supporting portion, and along the thickness direction of the bipolar plate assembly, the first sealing portion protrudes toward a first direction, and the first supporting portion protrudes toward a second direction;

[0008] A second monopolar plate, wherein the outer edge and the cavity of the second monopolar plate are both provided with a second supporting portion and a second sealing portion, and along the thickness direction of the bipolar plate assembly, the second supporting portion protrudes toward the first direction, and the second sealing portion protrudes toward the second direction;

[0009] wherein the first direction is opposite to the second direction;

[0010] Along the thickness direction of the bipolar plate assembly, the first monopolar plate and the second monopolar plate are stacked, the second support portion is embedded in the recess formed by the first sealing portion and fits with the first sealing portion; the first support portion is embedded in the recess formed by the second sealing portion and fits with the second sealing portion.

[0011] In a possible design, the first sealing portion is disposed adjacent to the first supporting portion;

[0012] The second sealing portion is disposed adjacent to the second supporting portion.

[0013] In a possible design, the first sealing portion and the first supporting portion are spaced apart from each other;

[0014] The second sealing portion is spaced apart from the second supporting portion.

[0015] In a possible design, a plurality of first flow holes arranged at intervals are provided at each cavity of the first monopolar plate, the first flow holes are communicated with the corresponding cavity and the first air inlet on the first monopolar plate, a first avoidance channel is provided between the first sealing portion and the second supporting portion, a second avoidance channel is provided between the second sealing portion and the first supporting portion, and the first avoidance channel and the second avoidance channel together constitute a partial structure of the first flow hole;

[0016] A plurality of second flow holes arranged at intervals are provided at each cavity of the second monopolar plate, and the second flow holes are connected with the corresponding cavity and the second air inlet on the second monopolar plate. A first avoidance channel is provided between the first sealing part and the second supporting part, and a second avoidance channel is provided between the second sealing part and the first supporting part, and the first avoidance channel and the second avoidance channel together constitute a partial structure of the second flow hole.

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

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

[0019] In a possible design, the first monopolar plate and the second monopolar 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 unipolar plate and the second unipolar plate and is located at the matching position of the first sealing portion and the second supporting portion or at the outer side of the matching position of the second sealing portion and the first supporting portion;

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

[0022] In a possible design, the welding position further includes a third welding position, which is arranged at the outer edge of the first unipolar plate and the second unipolar plate and is located at the matching position of the first sealing portion and the second supporting portion or at the inner side of the matching position of the second sealing portion and the first supporting portion;

[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 one possible design, the bipolar plate assembly further includes a first elastic seal and a second elastic seal;

[0025] The first elastic seal is arranged at the raised end of the first sealing portion, and the second elastic seal is arranged at the raised end of the second sealing portion.

[0026] The present application also provides a fuel cell, the fuel cell comprising:

[0027] Membrane electrode assembly;

[0028] 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.

[0029] In a possible design, the height of the first sealing portion is h1, the height of the second sealing portion is h2, the height of the proton membrane is h3, the height of the diffusion layer is h4, the height of the flow field region is h5, and the thickness of the proton membrane frame is h6;

[0030] Among them, h1=h3 / 2+h4+h5-h6 / 2; h2=h3 / 2+h4+h5-h6 / 2.

[0031] 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

[0032] Figure 1 A schematic diagram of a sealing structure of a fuel cell in one embodiment;

[0033] Figure 2 A schematic diagram of the structure of the bipolar plate assembly provided in this application;

[0034] Figure 3 for Figure 2 Schematic diagram of the local section along the AA direction;

[0035] Figure 4 This is a schematic diagram of the first monopolar plate provided in the present application facing the hydrogen field side;

[0036] Figure 5 This is a schematic diagram of the second monopolar plate provided in this application facing the water field side;

[0037] Figure 6 This is a schematic diagram of the second monopolar plate provided in this application facing the oxygen field side;

[0038] Figure 7 This is a schematic diagram of the first monopolar plate provided in this application facing the water field side;

[0039] Figure 8 A schematic diagram of the stacking arrangement of the bipolar plate assembly and the membrane electrode assembly provided in this application;

[0040] Fig. 9 A schematic diagram of the stacking arrangement of the bipolar plate assembly and the membrane electrode assembly provided in this application;

[0041] Fig.10 A schematic diagram of the distribution of welding positions of the first monopolar plate and the second monopolar plate provided in this application;

[0042] Fig.11 A schematic diagram of a cavity in a bipolar plate provided in the present application;

[0043] Fig.12 for Fig.11 Schematic diagram of the local section along the BB direction;

[0044] Fig.13 for Fig.11 Schematic diagram of the local section along the CC direction;

[0045] Fig.14 This is a schematic diagram of the first monopolar plate provided in the present application facing the hydrogen field side;

[0046] Fig.15 This is a schematic diagram of the first monopolar plate provided in this application facing the water field side;

[0047] Fig.16 This is a schematic diagram of the second monopolar plate provided in this application facing the water field side;

[0048] Fig.17 This is a schematic diagram of the second monopolar plate facing the oxygen field provided in this application.

[0049] Reference numerals:

[0050] 1′- cathode monopolar plate;

[0051] 2′- anode monopolar plate;

[0052] 3′- cathode seal;

[0053] 4′- anode seal;

[0054] 100-bipolar plate assembly;

[0055] 10- a first monopolar plate;

[0056] 11- first sealing part;

[0057] 111-First avoidance channel;

[0058] 12- first supporting portion;

[0059] 13- first flow hole;

[0060] 14- first welding position;

[0061] 15- second welding position;

[0062] 16-third welding position;

[0063] 17- first air inlet;

[0064] 20- second monopolar plate;

[0065] 21- second supporting portion;

[0066] 22- second sealing portion;

[0067] 221-Second avoidance channel;

[0068] 23- second flow hole;

[0069] 24- second air inlet;

[0070] 30-first elastic sealing member;

[0071] 40 - second elastic sealing member;

[0072] 50-Membrane electrode assembly.

[0073] 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

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] like Figure 1 The figure shows a schematic diagram of a sealing structure of a fuel cell in an embodiment, 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.

[0081] The cathode seal 3' and the anode seal 4' are generally made of rubber material.

[0082] Specifically, in a specific embodiment, 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.

[0083] Alternatively, in another specific embodiment, the cathode monopolar plate 1' and the anode monopolar plate 2' are first welded, and then adhesive is coated in 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 seal 3' and the anode seal 4'.

[0084] In the structure and preparation method of the bipolar plates and seals described above, the adhesives and sealing materials will be exposed to the use environment for a long time, directly contacting acid, heat, mechanical external forces, etc., and have poor durability. When preparing seals, due to the characteristics of the materials, 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.

[0085] To this end, this embodiment provides a fuel cell to solve the above technical problems.

[0086] The fuel cell includes a membrane electrode assembly and a bipolar plate assembly, which are stacked with the membrane electrode assembly. The membrane electrode assembly 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 assembly are to support the membrane electrode assembly, provide hydrogen, oxygen and coolant fluid channels and separate hydrogen and oxygen, collect electrons, conduct heat, etc.

[0087] The structure of the bipolar plate assembly will be described in detail below with reference to the accompanying drawings.

[0088] like Figure 2 The schematic diagram of the structure of the bipolar plate assembly is shown as follows: Figure 3 Shown Figure 2 The cross-sectional diagram at the AA position along the middle is shown in the figure. Figure 2 and Figure 3 The bipolar plate assembly 100 includes a first unipolar plate 10 and a second unipolar plate 20 . The first unipolar plate 10 and the second unipolar plate 20 are stacked along a thickness direction of the bipolar plate assembly 100 .

[0089] like Figure 4 FIG. 1 is a schematic diagram showing the first monopolar plate 10 facing the hydrogen field side. Figure 5 The second monopolar plate 20 is shown as a schematic diagram facing the water field side. Figures 2 to 5The first monopolar plate 10 is provided with a first sealing portion 11 and a first supporting portion 12 at the outer edge and the cavity position. Along the thickness direction of the bipolar plate assembly 100, the first sealing portion 11 protrudes toward the first direction, and the first supporting portion 12 protrudes toward the second direction. The second monopolar plate 20 is provided with a second supporting portion 21 and a second sealing portion 22 at the outer edge and the cavity position. Along the thickness direction of the bipolar plate assembly 100, the second supporting portion 21 protrudes toward the first direction, and the second sealing portion 22 protrudes toward the second direction.

[0090] The first direction is opposite to the second direction. That is, the protruding direction of the first sealing portion 11 is opposite to the protruding direction of the first supporting portion 12, and the protruding direction of the first sealing portion 11 is the same as the protruding direction of the second supporting portion 21. The protruding direction of the second sealing portion 22 is opposite to the protruding direction of the second supporting portion 21, and the protruding direction of the second sealing portion 22 is the same as the protruding direction of the first supporting portion 12.

[0091] Therefore, after the first monopolar plate 10 and the second monopolar plate 20 are stacked and connected to form a bipolar plate, the second support portion 21 can be embedded in the recess formed by the first sealing portion 11 and fit with the first sealing portion 11. Also, the first support portion 12 can be embedded in the recess formed by the second sealing portion 22 and fit with the second sealing portion 22.

[0092] In this embodiment, by forming the first sealing portion 11 and the first supporting portion 12 on the first monopolar plate 10, and forming the second sealing portion 22 and the second supporting portion 21 on the second monopolar plate 20, after the first monopolar plate 10 and the second monopolar plate 20 are connected, the second supporting portion 21 is embedded with the first sealing portion 11, and the first supporting portion 12 is embedded with the second sealing portion 22, so that the second supporting portion 21 can support the first sealing portion 11, and the first supporting portion 12 can support the second sealing portion 22. In this embodiment, by setting the second supporting portion 21 and the first sealing portion 11 to bulge on the same side and the two are arranged in a close relationship, the second supporting portion 21 can support the first sealing portion 11, and by setting the first supporting portion 12 and the second sealing portion 22 to bulge on the same side and the two are arranged in a close relationship, the first supporting portion 12 can support the second sealing portion 22, without setting other supporting structures, so as to achieve the double-layer self-supporting effect of the bipolar plate assembly 100, improve the supporting effect of the sealing structure, and thus extend the sealing effect of the bipolar plate assembly 100.

[0093] Furthermore, in the same bipolar plate, the first sealing portion 11 and the second sealing portion 22 are arranged alternately, so as to further ensure the supporting effect of the sealing structure.

[0094] It should be noted that if Figure 3In the bipolar plate assembly 100 shown, the outer edge of the bipolar plate is not on the same horizontal plane as the second sealing portion 22, that is, the outer edge of the bipolar plate may not fit with the membrane electrode assembly 50. Of course, the outer edge of the bipolar plate may fit with the membrane electrode assembly 50, which can be set according to actual conditions.

[0095] like Figure 6 and Figure 7 As shown, in some embodiments, the sealing structure at the periphery of the water cavity opening can be combined with the sealing structure at the outer edge of the electrode plate, or the supporting structure at the periphery of the water cavity opening can be combined with the supporting structure at the outer edge of the electrode plate.

[0096] In some embodiments, the first sealing portion 11 and the first supporting portion 12 may be disposed adjacent to each other, and correspondingly, the second sealing portion 22 and the second supporting portion 21 may be disposed adjacent to each other.

[0097] Alternatively, in some embodiments, the first sealing portion 11 and the first supporting portion 12 may be spaced apart, and correspondingly, the second sealing portion 22 and the second supporting portion 21 may be spaced apart.

[0098] Preferably, the first sealing portion 11 is disposed adjacent to the first supporting portion 12, and the second sealing portion 22 is disposed adjacent to the second supporting portion, so as to reduce the occupied area of ​​the sealing and supporting structures.

[0099] Furthermore, if Figure 8 The figure shows a schematic diagram of the stacked arrangement of the bipolar plate assembly 100 and the membrane electrode assembly 50. During assembly, along the thickness direction of the bipolar plate assembly 100, in the bipolar plate assemblies 100 on both sides of the membrane electrode assembly 50, the sealing structures are symmetrically arranged along the membrane electrode assembly 50 to ensure the sealing effect between the bipolar plate assembly 100 and the membrane electrode assembly 50.

[0100] Please continue to refer to Figure 8 In some embodiments, the height of the first sealing portion 11 is h1, the height of the second sealing portion 22 is h2, the height of the proton membrane is h3, the height of the diffusion layer is h4, the height of the flow field region is h5, and the thickness of the proton membrane frame is h6. h1 = h3 / 2 + h4 + h5 - h6 / 2; h2 = h3 / 2 + h4 + h5 - h6 / 2.

[0101] In this embodiment, by limiting the height of the first sealing portion 11 and the second sealing portion 22, the first sealing portion 11 and the stacked sealing portion can be closely contacted with the two end surfaces of the proton membrane frame, respectively, to ensure the sealing effect.

[0102] The first sealing portion 11 around the water cavity opening can be combined with the first sealing portion 11 around the electrode plate, and the second sealing portion 22 around the water cavity opening can be combined with the second sealing portion 22 around the electrode plate.

[0103] like Fig. 9 The figure shows a schematic diagram of a stacked arrangement of a bipolar plate assembly 100 and a membrane electrode assembly 50. To further enhance the sealing effect of the bipolar plate assembly 100, the bipolar plate assembly 100 further includes a first elastic seal 30 and a second elastic seal 40. The first elastic seal 30 is disposed at the raised end of the first sealing portion 11, and the second elastic seal 40 is disposed at the raised end of the second sealing portion 22, so that the first elastic seal 30 further seals the joint surface between the first sealing portion 11 and the adjacent proton membrane frame, and the second elastic seal 40 further seals the joint surface between the second sealing portion 22 and the adjacent proton membrane frame.

[0104] like Fig.10 The figure shows a distribution diagram of welding positions of the first monopolar plate 10 and the second monopolar plate 20. In some embodiments, the first monopolar plate 10 and the second monopolar plate 20 are welded and fixed, and a plurality of welding positions are provided between the two.

[0105] Specifically, the welding position includes a first welding position 14 and a second welding position 15. The first welding position 14 is arranged at the outer edge of the first unipolar plate 10 and the second unipolar plate 20, and is located at the outer side of the matching position of the first sealing portion 11 and the second supporting portion 21 or the matching position of the second sealing portion 22 and the first supporting portion 12. The first welding position 14 mainly serves to fix the first unipolar plate 10 and the second unipolar plate 20, and also limits the gas from leaking out through the matching position of the first sealing portion 11 and the second supporting portion 21 or the matching position of the second sealing portion 22 and the first supporting portion 12.

[0106] It should be noted that the positions of the first sealing portion 11 and the first supporting portion 12 on the first unipolar plate 10 are not limited, and the first sealing portion 11 may be arranged closer to the outer edge of the first unipolar plate 10, or the first supporting portion 12 may be arranged closer to the outer edge of the first unipolar plate 10. Correspondingly, the positions of the second sealing portion 22 and the second supporting portion 21 on the second unipolar plate 20 are also not limited, and may be specifically distributed according to the positions of the first sealing portion 11 and the first supporting portion 12 on the first unipolar plate 10. Therefore, when the first unipolar plate 10 and the second unipolar plate 20 are stacked, when the first sealing portion 11 and the second supporting portion 21 are closer to the outer edge position, the first welding position 14 is located outside the matching position of the first sealing portion 11 and the second supporting portion 21. Similarly, when the second sealing portion 22 and the first supporting portion 12 are closer to the outer edge position, the first welding position 14 is located outside the matching position of the second sealing portion 22 and the first supporting portion 12.

[0107] The second welding position 15 is arranged at the periphery of the gas cavity opening of the first monopolar plate 10 and the gas cavity opening of the second monopolar plate 20, and the second welding position 15 surrounds the first sealing portion 11 or the second sealing portion 22 located at the gas cavity opening. The second welding position 15 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 achieve fixing the first monopolar plate 10 and the second monopolar plate 20 while limiting the gas flow, reducing the corrosion of the plates, and extending the service life of the plates.

[0108] Furthermore, the welding position also includes a third welding position 16, which is arranged at the outer edge of the first monopolar plate 10 and the second monopolar plate 20, and is located at the matching position of the first sealing portion 11 and the second supporting portion 21 or at the inner side of the matching position of the second sealing portion 22 and the first supporting portion 12. Part of the third welding position 16 located at the periphery of the gas cavity port overlaps with part of the second welding position 15. In this embodiment, by setting the third welding position 16, 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.

[0109] It should be noted that, similarly to the above, the positions of the first sealing portion 11 and the first supporting portion 12 on the first monopolar plate 10 are not limited, and the positions of the second sealing portion 22 and the second supporting portion 21 on the second monopolar plate 20 are also not limited. Therefore, when the first monopolar plate 10 and the second monopolar plate 20 are stacked, when the first sealing portion 11 and the second supporting portion 21 are closer to the outer edge position, the third welding position 16 is located on the inner side of the matching position of the second sealing portion 22 and the first supporting portion 12. Similarly, when the second sealing portion 22 and the first supporting portion 12 are closer to the outer edge position, the third welding position 16 is located on the outer side of the matching position of the first sealing portion 11 and the second supporting portion 21.

[0110] like Fig.11 The schematic diagram of a cavity in a bipolar plate is shown as follows. Fig.12 Shown Fig. 9 Schematic diagram of the cross section along the BB direction, Fig.13 Shown Fig. 9 In some embodiments, please refer to Figure 4 , Figure 5 , Figures 11 to 13, a plurality of first flow holes 13 are arranged at intervals at each cavity of the first monopolar plate 10, and the first flow holes 13 are connected to the corresponding cavity and the first air inlet 17 on the first monopolar plate 10. A first avoidance channel 111 is provided between the first sealing portion 11 and the second supporting portion 21, and a second avoidance channel 221 is provided between the second sealing portion 22 and the first supporting portion 12. The first avoidance channel 111 and the second avoidance channel 221 together constitute a partial structure of the first flow hole 13. Among them, the first sealing portion 11 and the second supporting portion 21, as well as the second sealing portion 22 and the first supporting portion 12 in a chimeric state are still provided between the intervals of adjacent first flow holes 13.

[0111] That is, a first flow hole 13 is provided on one side of each cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) of the first monopolar plate 10, and when the first sealing portion 11, the second supporting portion 21, the second sealing portion 22 and the first supporting portion 12 are formed, a first avoidance channel 111 and a second avoidance channel 221 are reserved for the first flow hole 13 to communicate with each other, so as to realize the communication between the first flow hole 13 and the corresponding cavity opening.

[0112] Among them, the first flow hole 13 is connected to the distribution area at the water cavity near one end of the flow field, and is connected to the air cavity plate inflow hole in the air cavity area.

[0113] A plurality of second flow holes 23 are provided at intervals at each cavity of the second monopolar plate 20, and the second flow holes 23 are connected with the corresponding cavity and the second air inlet 24 on the second monopolar plate 20. A first avoidance channel 111 is provided between the first sealing portion 11 and the second supporting portion 21, and a second avoidance channel 221 is provided between the second sealing portion 22 and the first supporting portion 12. The first avoidance channel 111 and the second avoidance channel 221 together constitute a partial structure of the second flow hole 23. Among them, the first sealing portion 11 and the second supporting portion 21, as well as the second sealing portion 22 and the first supporting portion 12 in a chimeric state are still provided between the intervals of adjacent second flow holes 23.

[0114] That is, a second flow hole 23 is provided on one side of each cavity opening (hydrogen cavity opening, water cavity opening and oxygen cavity opening) of the second monopolar plate 20, and when the first sealing portion 11, the second supporting portion 21, the sealing portion 22 and the first supporting portion 12 are formed, a first avoidance channel 111 and a second avoidance channel 221 that are connected are reserved for the second flow hole 23 to realize the connection between the second flow hole 23 and the corresponding cavity opening.

[0115] Among them, the second flow hole 23 is connected to the distribution area at the water cavity near one end of the flow field, and is connected to the air cavity plate inflow hole in the air cavity area.

[0116] It should be noted that the first flow hole 13 and the second flow hole 23 may be the same flow channel connected to a cavity in the bipolar plate, but the air inlets (the first air inlet 17 and the second air inlet 24) connected to the two are different.

[0117] The distribution of the first flow hole 13 and the first sealing portion 11 and the first supporting portion 12 of the first monopolar plate 10, and the distribution of the second flow hole 23 and the second sealing portion 22 and the second supporting portion 21 of the second monopolar plate 20 can be as follows: Figures 14 to 16 Specifically, Fig.14 FIG. 1 is a schematic diagram showing the first monopolar plate 10 in the bipolar plate facing the hydrogen field side. Fig.15 FIG. 1 is a schematic diagram showing the first monopolar plate 10 facing the water field side. Fig.16 FIG. 2 is a schematic diagram showing the second monopolar plate 20 facing the water field side. Fig.17 FIG. 1 is a schematic diagram of the second unipolar plate 20 facing the oxygen field.

[0118] Specifically, the depth of the first flow hole 13 is d1, the height of the first sealing portion 11 is h1, and d1 and h1 satisfy: 30%≤d1 / h1≤99%.

[0119] Illustratively, d1 / h1 may be 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, etc.

[0120] In this embodiment, if d1 / h1 is too large (e.g., d1 / h1>99%), the height of the first flow hole 13 is higher than the height of the first sealing portion 11, and the first sealing portion 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 hole 13 is too low, affecting the circulation of gas.

[0121] The depth of the second flow hole 23 is d2, and the height of the second sealing portion 22 is h2. d2 and h2 satisfy: 30%≤d2 / h2≤99%.

[0122] Illustratively, d2 / h2 may be 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, etc.

[0123] In this embodiment, if d2 / h2 is too large (e.g., d2 / h2>99%), the height of the second flow hole 23 is higher than the height of the second sealing portion 22, and the second sealing portion 22 may not be able to prevent gas leakage. If d2 / h2 is too large (e.g., d2 / h2<30%), the height of the second flow hole 23 is too low, affecting the circulation of gas.

[0124] In combination with the above structural content, in a specific embodiment, the bipolar plate assembly 100 includes a first unipolar plate 10 and a second unipolar plate 20. A first sealing portion 11 and a first supporting portion 12 are formed on the first unipolar plate 10 by a stamping process, and a second sealing portion 22 and a second supporting portion 21 are formed on the second unipolar plate 20. The first sealing portion 11 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2. The height of the second sealing portion 22 = proton membrane height / 2 + diffusion layer height + plate flow field area height - proton membrane frame thickness / 2.

[0125] The second sealing portion 22 of the second monopolar plate 20 (cathode monopolar plate) protrudes toward the oxygen field side, the first supporting portion 12 of the first monopolar plate 10 (anode monopolar plate) protrudes toward the water field side, and the first supporting portion 12 is completely embedded in the concave filling formed by the second sealing portion 22. The first sealing portion 11 of the first monopolar plate 10 protrudes toward the hydrogen field side, the second supporting portion 21 of the second monopolar plate 20 protrudes toward the water field side, and the second supporting portion 21 is completely embedded in the concave filling formed by the first sealing portion 11.

[0126] At the cavity opening, the height of the first flow hole 13 is 50% of the height of the first sealing portion 11, and the first flow hole 13 is connected to the distribution area at the water cavity near the flow field end, and is connected to the air cavity electrode plate inflow hole at the air cavity. The height of the second flow hole 23 is 50% of the height of the second sealing portion 22, and the second flow hole 23 is connected to the distribution area at the water cavity near the flow field end, and is connected to the air cavity electrode plate inflow hole at the air cavity.

[0127] After the first monopolar plate 10 and the second monopolar plate 20 are stamped respectively, the first monopolar plate 10 and the second monopolar plate 20 are welded and fixed. Among them, the two have at least three welding positions. The first welding position 14 is arranged at the outer edge of the first monopolar plate 10 and the second monopolar plate 20, and is located on the outside of the first sealing portion 11 (and the second support portion 21) and the second sealing portion 22 (and the first support portion 12). The second welding position 15 is arranged at the periphery of the air cavity opening of the first monopolar plate 10 and the air cavity opening of the second monopolar plate 20. The third welding position 16 is arranged at the outer edge of the first monopolar plate 10 and the second monopolar plate 20, and is located on the inner side of the first sealing portion 11 (and the second support portion 21) and the second sealing portion 22 (and the first support portion 12). Part of the third welding position 16 located on the periphery of the air cavity opening overlaps with part of the second welding position 15 to reduce the welding process. When the membrane electrode assembly 50 and the bipolar plate assembly 100 are stacked and assembled, in the bipolar plate assemblies 100 on both sides of the membrane electrode assembly 50 , the sealing structures are symmetrical along the membrane electrode assembly 50 .

[0128] In another specific embodiment, the bipolar plate assembly 100 includes a first unipolar plate 10, a second unipolar plate 20, a first elastic seal 30 and a second elastic seal 40. A stamping process is used to form a first sealing portion 11 and a first supporting portion 12 on the first unipolar plate 10, and a second sealing portion 22 and a second supporting portion 21 on the second unipolar plate 20. The first sealing portion 11 = proton membrane height / 2+diffusion layer height+polar plate flow field area height-proton membrane frame thickness / 2. The height of the second sealing portion 22 = proton membrane height / 2+diffusion layer height+polar plate flow field area height-proton membrane frame thickness / 2.

[0129] The second sealing portion 22 of the second monopolar plate 20 (cathode monopolar plate) protrudes toward the oxygen field side, the first supporting portion 12 of the first monopolar plate 10 (anode monopolar plate) protrudes toward the water field side, and the first supporting portion 12 is completely embedded in the concave filling formed by the second sealing portion 22. The first sealing portion 11 of the first monopolar plate 10 protrudes toward the hydrogen field side, the second supporting portion 21 of the second monopolar plate 20 protrudes toward the water field side, and the second supporting portion 21 is completely embedded in the concave filling formed by the first sealing portion 11.

[0130] The first elastic seal 30 is arranged at the convex end of the first sealing part 11, and the second elastic seal 40 is arranged at the convex end of the second sealing part 22. The first elastic seal 30 and the second elastic seal 40 can be formed by directly spraying the fluorine coating. Alternatively, the first elastic seal 30 and the second elastic seal 40 can also be composed of a material with superelastic properties such as a silicone layer, a fluorine rubber layer, and an EPDM rubber layer.

[0131] At the cavity opening, the height of the first flow hole 13 is 75% of the height of the first sealing portion 11, and the first flow hole 13 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 height of the second flow hole 23 is 75% of the height of the second sealing portion 22, and the second flow hole 23 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.

[0132] After the first monopolar plate 10 and the second monopolar plate 20 are stamped respectively, the first monopolar plate 10 and the second monopolar plate 20 are welded and fixed. Among them, the two have at least three welding positions. The first welding position 14 is arranged at the outer edge of the first monopolar plate 10 and the second monopolar plate 20, and is located on the outside of the first sealing portion 11 (and the second support portion 21) and the second sealing portion 22 (and the first support portion 12). The second welding position 15 is arranged at the periphery of the air cavity opening of the first monopolar plate 10 and the air cavity opening of the second monopolar plate 20. The third welding position 16 is arranged at the outer edge of the first monopolar plate 10 and the second monopolar plate 20, and is located on the inner side of the first sealing portion 11 (and the second support portion 21) and the second sealing portion 22 (and the first support portion 12). Part of the third welding position 16 located on the periphery of the air cavity opening overlaps with part of the second welding position 15 to reduce the welding process. When the membrane electrode assembly 50 and the bipolar plate assembly 100 are stacked and assembled, in the bipolar plate assemblies 100 on both sides of the membrane electrode assembly 50 , the sealing structures are symmetrical along the membrane electrode assembly 50 .

[0133] 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 (100) comprises: A first monopolar plate (10), wherein the outer edge and the cavity of the first monopolar plate (10) are both provided with a first sealing portion (11) and a first supporting portion (12), and along the thickness direction of the bipolar plate assembly (100), the first sealing portion (11) protrudes toward a first direction, and the first supporting portion (12) protrudes toward a second direction; A second monopolar plate (20), wherein the outer edge and the cavity of the second monopolar plate (20) are both provided with a second supporting portion (21) and a second sealing portion (22), and along the thickness direction of the bipolar plate assembly (100), the second supporting portion (21) protrudes toward the first direction, and the second sealing portion (22) protrudes toward the second direction; wherein the first direction is opposite to the second direction; Along the thickness direction of the bipolar plate assembly (100), the first monopolar plate (10) and the second monopolar plate (20) are stacked, the second supporting portion (21) is embedded in a recess formed by the first sealing portion (11) and fits with the first sealing portion (11); the first supporting portion (12) is embedded in a recess formed by the second sealing portion (22) and fits with the second sealing portion (22).

2. The bipolar plate assembly according to claim 1, characterized in that: The first sealing portion (11) is arranged adjacent to the first supporting portion (12); The second sealing portion (22) is arranged adjacent to the second supporting portion (21).

3. The bipolar plate assembly according to claim 1, characterized in that: The first sealing portion (11) and the first supporting portion (12) are arranged at a distance; The second sealing portion (22) is spaced apart from the second supporting portion (21).

4. The bipolar plate assembly according to claim 1, characterized in that: A plurality of first flow holes (13) arranged at intervals are provided at each cavity of the first monopolar plate (10); the first flow holes (13) are in communication with the corresponding cavity and the first air inlet (17) on the first monopolar plate (10); a first avoidance channel (111) is provided between the first sealing portion (11) and the second supporting portion (21); a second avoidance channel (221) is provided between the second sealing portion (22) and the first supporting portion (12); the first avoidance channel (111) and the second avoidance channel (221) together constitute a partial structure of the first flow hole (13); A plurality of second flow holes (23) arranged at intervals are provided at each cavity of the second monopolar plate (20); the second flow holes (23) are in communication with the corresponding cavity and the second air inlet (24) on the second monopolar plate (20); a first avoidance channel (111) is provided between the first sealing portion (11) and the second supporting portion (21); a second avoidance channel (221) is provided between the second sealing portion (22) and the first supporting portion (12); the first avoidance channel (111) and the second avoidance channel (221) together constitute a partial structure of the second flow hole (23).

5. The bipolar plate assembly according to claim 4, characterized in that: The depth of the first flow hole (13) is d1, the height of the first sealing portion (11) is h1, and d1 and h1 satisfy: 30%≤d1 / h1≤99%; The depth of the second flow hole (23) is d2, the height of the second sealing portion (22) 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 monopolar plate (10) and the second monopolar plate (20) are welded and fixed, and a plurality of welding positions are provided on the two. The welding position comprises a first welding position (14) and a second welding position (15); the first welding position (14) is arranged at the outer edge of the first unipolar plate (10) and the second unipolar plate (20), and is located at a matching position between the first sealing portion (11) and the second supporting portion (21) or at the outer side of a matching position between the second sealing portion (22) and the first supporting portion (12); The second welding position (15) is arranged at the periphery of the air cavity opening of the first monopolar plate (10) and the air cavity opening of the second monopolar plate (20).

7. The bipolar plate assembly according to claim 6, characterized in that: The welding position further includes a third welding position (16), wherein the third welding position (16) is arranged at the outer edge of the first unipolar plate (10) and the second unipolar plate (20), and is located at a matching position between the first sealing portion (11) and the second supporting portion (21) or at an inner side of a matching position between the second sealing portion (22) and the first supporting portion (12); Part of the third welding position (16) located at the periphery of the air cavity opening overlaps with part of the second welding position (15).

8. The bipolar plate assembly according to claim 1, characterized in that: The bipolar plate assembly (100) further comprises a first elastic seal (30) and a second elastic seal (40); The first elastic sealing member (30) is arranged at the raised end of the first sealing portion (11), and the second elastic sealing member (40) is arranged at the raised end of the second sealing portion (22).

9. A fuel cell, characterized in that: The fuel cell comprises: Membrane electrode assembly (50); A bipolar plate assembly (100), wherein the bipolar plate assembly (100) is the bipolar plate assembly (100) according to any one of claims 1 to 8, and the bipolar plate assembly (100) is stacked with the membrane electrode assembly (50).

10. The fuel cell according to claim 9, characterized in that The height of the first sealing portion (11) is h1, the height of the second sealing portion (22) 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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