A bipolar plate structure and a fuel cell stack

Abstract

The application discloses a bipolar plate structure, which comprises an anode plate, a cathode plate, a capillary core and a phase change medium. The anode plate and the cathode plate are connected to form a vacuum sealed cavity. The capillary core is arranged on the inner wall of the vacuum sealed cavity, and the phase change medium is filled in the vacuum sealed cavity. The bipolar plate comprises a heating area and a heat dissipation area. The heating area is arranged at one end of the bipolar plate, and the heat dissipation area is arranged at the other end of the bipolar plate. The phase change medium can absorb the heat of the heating area and transmit the heat to the heat dissipation area. The heat is diffused through the heat dissipation area. Compared with the prior art, the bipolar plate structure does not need to be provided with additional cooling equipment. Only the deformation of the existing bipolar plate structure can achieve good heat dissipation effect. The bipolar plate structure is simple in structure, high in heat transfer efficiency and high in heat dissipation efficiency.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a bipolar plate structure and a fuel cell stack. Background Technology

[0002] A fuel cell stack is a structure composed of a sandwich structure consisting of multiple bipolar plates and membrane electrode assemblies (MEAs). The function of the bipolar plates is to transport reactant gases, commonly hydrogen and air, through gas channels to the active region of the MEA, enabling the electrochemical reaction to occur and generating an electric current. Simultaneously, the bipolar plates also play a role in electron transfer. Furthermore, the sealing structure on the bipolar plates keeps the gas within the reaction zone, preventing leakage to the external environment.

[0003] After the bipolar plates and membrane electrode assembly are assembled into a fuel cell stack, a cooling method is needed to dissipate the waste heat generated during power generation. Common cooling methods are air cooling or water cooling. Water cooling requires the bipolar plates to be designed as a two-plate, three-cavity structure, where the cavity between the bipolar plates serves as the space for coolant flow. Air-cooled fuel cell stacks or bipolar plates often have an open cathode structure, where the cathode cavity and the air cooling cavity are in the same cavity. Air and water are introduced into the reaction cavity through external ventilation equipment such as fans. Some of the air is used to provide oxygen for the cathode reaction, and because the cathode has an open structure, excess air enters from one side of the bipolar plates and flows out from the other, carrying away the heat generated during the reaction. Of the two cooling methods, water cooling can usually remove more heat, allowing the fuel cell stack to operate at a higher charge density. However, water cooling systems are complex to design, requiring additional water pumps, controllers, water tanks, piping, and external heat sinks, resulting in a larger and more expensive water cooling system. Air cooling systems, due to their simpler structure, are smaller and less expensive. However, due to limited air cooling capacity and the fact that open cathodes typically cannot provide higher gas pressures, the operating point of single fuel cell operation is relatively low.

[0004] Therefore, how to provide a bipolar plate structure that is simple in structure, has high heat transfer efficiency, and high heat dissipation efficiency is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a bipolar plate structure that is not only simple in structure, but also has high heat transfer efficiency and high heat dissipation efficiency.

[0006] Another object of the present invention is to provide a fuel cell stack.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A bipolar plate structure includes an anode plate, a cathode plate, a capillary wick, and a phase change medium. The anode plate and the cathode plate are connected to form a vacuum-sealed cavity. The capillary wick is disposed on the inner wall of the vacuum-sealed cavity, and the phase change medium is filled in the vacuum-sealed cavity.

[0009] The bipolar plate includes a heating area and a heat dissipation area. The heating area is located at one end of the bipolar plate, and the heat dissipation area is located at the other end of the bipolar plate. The phase change medium can absorb the heat from the heating area and transfer the heat to the heat dissipation area, where the heat is diffused.

[0010] Preferably, the anode plate includes a first surface and a second surface, and the cathode plate includes a third surface and a fourth surface, wherein the second surface and the fourth surface form the inner wall of the vacuum-sealed cavity.

[0011] Preferably, the heating area includes a first heating area disposed on the anode plate and a second heating area disposed on the cathode plate;

[0012] The heat dissipation area includes a first heat dissipation area disposed on the anode plate and a second heat dissipation area disposed on the cathode plate.

[0013] Preferably, a serpentine flow channel is provided on the first heating area;

[0014] The first heat dissipation area is provided with a plurality of first convex cavities, and the first convex cavities protrude in the direction of the second surface.

[0015] Preferably, the second heating area is provided with a plurality of second convex cavities and third convex cavities, and the second convex cavities and the third convex cavities are spaced apart;

[0016] The second convex cavity and the third convex cavity protrude in opposite directions; the second convex cavity protrudes toward the third surface, and the third convex cavity protrudes toward the fourth surface.

[0017] A fourth convex cavity is provided on the second heat dissipation area, and the fourth convex cavity protrudes in the direction of the fourth surface.

[0018] Preferably, the anode plate is provided with a plurality of strip-shaped first protrusions, and the cathode plate is provided with a plurality of second protrusions corresponding to the first protrusions. The protrusion directions of the first protrusions and the second protrusions are opposite. The first protrusions and the second protrusions cooperate to form a cylindrical cavity. External gas can flow along its axial direction in the cylindrical cavity, and the phase change medium can flow in a direction perpendicular to its axial direction in the cylindrical cavity.

[0019] A first connecting portion is provided between any two adjacent first protrusions, and a second connecting portion corresponding to the first connecting portion is provided between any two adjacent second protrusions.

[0020] Preferably, the liquid inlet of the anode plate is located on one side parallel to the axial direction of the cylindrical cavity, and the liquid inlet of the cathode plate is located on one side perpendicular to the axial direction of the cylindrical cavity.

[0021] Preferably, the first connecting part is a first groove, the second connecting part is a second groove, the bottom of the first groove and the top of the second groove are in contact, the first groove is provided with a first through hole for the phase change medium to pass through, and the second groove is provided with a second through hole for the phase change medium to pass through.

[0022] Preferably, the first connecting part is stamped with a plurality of support blocks, the bottom end face of the support blocks is connected to the second connecting part, and there is a gap between any two connected support blocks for the phase change medium to pass through.

[0023] Preferably, a plurality of support columns are provided between the first connecting part and the second connecting part, and the two ends of the support columns are respectively connected to the first connecting part and the second connecting part;

[0024] The multiple support portions are arranged sequentially along the length direction of the first protrusion and the second protrusion, and there is a preset distance between any two adjacent support columns to facilitate the passage of the phase change medium.

[0025] A fuel cell stack includes a membrane electrode assembly and a bipolar plate structure as described in any of the preceding claims;

[0026] There are multiple bipolar plates and multiple membrane electrodes, and any one of the membrane electrodes is disposed between any two adjacent bipolar plates.

[0027] As can be seen from the above technical solution, the phase change medium absorbs heat in the heating area of ​​the bipolar plate and evaporates into a gaseous medium. The gaseous medium flows along the axis of the vacuum-sealed cavity to the heat dissipation area. In the heat dissipation area, the gaseous medium releases heat and condenses into a liquid medium before entering the capillary wick. The capillary wick, through capillary force, draws the liquid medium back from the heat dissipation area to the heating area, thus forming an internal self-circulation. Since the vacuum-sealed cavity of the bipolar plate is filled with a phase change medium, the heat generated in the heating area of ​​the bipolar plate can be transferred to the heat dissipation area through the absorption and release of latent heat of phase change, and then diffused through the heat dissipation area, thereby effectively reducing the temperature of the heating area. Compared with the prior art, the above bipolar plate structure does not require additional cooling equipment. It only needs to be modified on the existing bipolar plate structure to achieve a good heat dissipation effect. It is not only simple in structure, but also has high heat transfer efficiency and high heat dissipation efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the bipolar plate disclosed in the embodiments of the present invention;

[0030] Figure 2 This is a schematic diagram of the anode plate disclosed in the first embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the cathode plate disclosed in the first embodiment of the present invention;

[0032] Figure 4 This is an enlarged structural schematic diagram of the heating area of ​​the cathode plate disclosed in the first embodiment of the present invention;

[0033] Figure 5 This is a schematic cross-sectional view of the cathode plate disclosed in the first embodiment of the present invention;

[0034] Figure 6 for Figure 5 Front view structural diagram;

[0035] Figure 7 This is a schematic diagram of the bipolar plate disclosed in the second embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of the bipolar plate disclosed in the third embodiment of the present invention;

[0037] Figure 9 This is a cross-sectional enlarged structural diagram of the bipolar plate disclosed in the third embodiment of the present invention;

[0038] Figure 10 This is a schematic diagram of the bipolar plate disclosed in the fourth embodiment of the present invention;

[0039] Figure 11 This is a cross-sectional enlarged structural diagram of the bipolar plate disclosed in the fourth embodiment of the present invention;

[0040] Figure 12 This is a schematic diagram of the installation structure of the cathode plate and support column disclosed in the fifth embodiment of the present invention;

[0041] Figure 13 This is a cross-sectional enlarged structural diagram of the bipolar plate disclosed in the fifth embodiment of the present invention;

[0042] Figure 14 This is a schematic diagram of the structure of the bipolar plate and membrane electrode as disclosed in the embodiments of the present invention.

[0043] The names of the components are as follows:

[0044] 100 is the anode plate, 101 is the first heating area, 1011 is the serpentine flow channel, 102 is the first heat dissipation area, 1021 is the first protruding cavity, 103 is the first protrusion, 104 is the first connecting part, and 1041 is the first through hole.

[0045] 200 is the cathode plate, 201 is the second heating area, 2011 is the second convex cavity, 2012 is the third convex cavity, 202 is the second heat dissipation area, 2021 is the fourth convex cavity, 203 is the second protrusion, 204 is the second connecting part, 300 is the phase change medium, 400 is the capillary wick, 500 is the recessed part, and 600 is the support column. Detailed Implementation

[0046] In view of this, the core of the present invention is to provide a bipolar plate structure that is not only simple in structure, but also has high heat transfer efficiency and high heat dissipation efficiency.

[0047] Another core aspect of this invention is to provide a fuel cell stack.

[0048] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Please refer to... Figures 1 to 14 .

[0049] Please refer to Figure 1The bipolar plate structure disclosed in the embodiments of the present invention includes an anode plate 100, a cathode plate 200 and a phase change medium 300. The anode plate 100 and the cathode plate 200 are connected to form a vacuum-sealed cavity. A capillary wick 400 is disposed on the inner wall of the vacuum-sealed cavity, and the phase change medium 300 is filled in the vacuum-sealed cavity.

[0050] The bipolar plate includes a heating area and a heat dissipation area. The heating area is located at one end of the bipolar plate, and the heat dissipation area is located at the other end of the bipolar plate. The phase change medium 300 can absorb the heat from the heating area and transfer the heat to the heat dissipation area, where the heat is diffused.

[0051] After absorbing heat in the heating area of ​​the bipolar plate, the phase change medium 300 evaporates into a gaseous medium. The gaseous medium flows along the axis of the vacuum-sealed cavity to the heat dissipation area. In the heat dissipation area, the gaseous medium releases heat and condenses into a liquid medium before entering the capillary core. The capillary core draws the liquid medium back from the heat dissipation area to the heating area through capillary force, thus forming an internal self-circulation.

[0052] Because the vacuum-sealed cavity of the bipolar plate is filled with phase change medium 300, the heat generated in the heating area of ​​the bipolar plate can be transferred to the heat dissipation area through the absorption and release of latent heat of phase change. The heat is then diffused through the heat dissipation area, effectively reducing the temperature of the heating area. Compared with existing technologies, the above bipolar plate structure does not require additional cooling equipment; it only needs to be modified from the existing bipolar plate structure to achieve excellent heat dissipation. It is not only simple in structure but also has high heat transfer and heat dissipation efficiency.

[0053] It needs to be explained that the appendix Figure 1 The solid straight lines represent the paths of liquid media, while the dashed straight lines represent the paths of gaseous media.

[0054] To avoid interference between the flow direction of external gas and the flow direction of internal phase change medium, which would prevent the internal phase change medium from flowing smoothly, the above-mentioned technical problem will be solved through the following five specific embodiments, thereby ensuring that the phase change medium 300 flows smoothly within the bipolar plate.

[0055] Please refer to Figures 2 to 6 In the bipolar plate structure disclosed in the first embodiment of the present invention, the anode plate 100 includes a first surface and a second surface, and the cathode plate 200 includes a third surface and a fourth surface, wherein the second surface and the fourth surface form the inner wall of the vacuum-sealed cavity, and the phase change medium 300 is filled in the vacuum-sealed cavity.

[0056] Correspondingly, the first surface of the anode plate 100 is the outer wall of the anode plate 100, and the third surface of the cathode plate 200 is the outer wall of the cathode plate 200. The first surface of the anode plate 100 and the third surface of the cathode plate 200 are in contact with the membrane electrode, and an electrochemical reaction occurs under the action of the reaction gas to generate current.

[0057] As a first embodiment of the present invention, the bipolar plate structure disclosed in this embodiment of the present invention includes a first heating region 101 disposed on the anode plate 100 and a second heating region 201 disposed on the cathode plate 200; and a heat dissipation region including a first heat dissipation region 102 disposed on the anode plate 100 and a second heat dissipation region 202 disposed on the cathode plate 200.

[0058] The first heating area 101 is provided with a serpentine flow channel 1011, and the first heat dissipation area 102 is provided with a plurality of first convex cavities 1021, and the first convex cavities 1021 protrude toward the second surface.

[0059] The second heating area 201 is provided with a plurality of second convex cavities 2011 and third convex cavities 2012. The second convex cavities 2011 and third convex cavities 2012 are arranged at intervals. The convex directions of the second convex cavities 2011 and third convex cavities 2012 are opposite. The second convex cavity 2011 protrudes towards the third surface, and the third convex cavity 2012 protrudes towards the fourth surface.

[0060] The second heat dissipation area 202 is provided with a fourth convex cavity 2021, which protrudes in the direction of the fourth surface.

[0061] After the anode plate 100 and cathode plate 200 are assembled, the second convex cavity 2011 functions as a gas flow field, which can transport gas to the reaction zone. The third convex cavity 2012 supports the anode plate 100 and cathode plate 200 and forms a vacuum and connected cavity.

[0062] The first convex cavity 1021 on the first heat dissipation area 102 and the fourth convex cavity 2021 on the second heat dissipation area 202 form heat dissipation "fins", which greatly enhances the heat dissipation area. Compared with the heat dissipation area of ​​the traditional air-cooled structure, the heat dissipation area of ​​this structure is increased by 2 to 3 times, which not only facilitates heat dissipation but also further improves the power density of the fuel cell stack.

[0063] As embodiments 2-5 of the present invention, the bipolar plate structure disclosed in the embodiments of the present invention has a plurality of strip-shaped first protrusions 103 provided on the anode plate and a plurality of second protrusions 203 corresponding to the first protrusions 103 provided on the cathode plate. The protrusion directions of the first protrusions 103 and the second protrusions 203 are opposite. The first protrusions 103 and the second protrusions 203 cooperate to form a cylindrical cavity. External gas can flow along its axial direction in the cylindrical cavity, and the phase change medium 300 can flow in a direction perpendicular to its axial direction in the cylindrical cavity.

[0064] A first connecting portion 104 is provided between any two adjacent first protrusions 103, and a second connecting portion 204 corresponding to the first connecting portion 104 is provided between any two adjacent second protrusions 203.

[0065] As a second preferred embodiment, please refer to Figure 7 The liquid inlet of the anode plate 100 is located on one side parallel to the axis of the cylindrical cavity, while the liquid inlet of the cathode plate 200 is located on one side perpendicular to the axis of the cylindrical cavity. This arrangement allows a channel for the phase change medium 300 to flow between the anode plate 100 and the cathode plate 200, ensuring smooth flow of the phase change medium 300.

[0066] As a third preferred embodiment, please refer to Figures 8 to 9 In the bipolar plate structure disclosed in this embodiment of the invention, the first connecting part 104 is preferably a first groove, and the second connecting part 204 is preferably a second groove. The bottom of the first groove and the top of the second groove are in contact. The first groove has a first through hole 1041 for the phase change medium 300 to pass through, and the second groove has a second through hole for the phase change medium 300 to pass through. The phase change medium 300 can flow through the first through hole 1041 and the second through hole within the sealed cavity formed by the bipolar plate.

[0067] As a fourth preferred embodiment, please refer to Figures 10 to 11 The bipolar plate structure disclosed in this embodiment of the invention has multiple support blocks 500 stamped on the first connecting portion 104. The bottom end face of the support block 500 is connected to the second connecting portion 204, and there is a gap between any two connected support blocks 500 for the phase change medium 300 to pass through. With this configuration, the phase change medium 300 can flow through the gap between any two adjacent support blocks 500.

[0068] As a fifth preferred embodiment, please refer to Figures 12 to 13 In the bipolar plate structure disclosed in the embodiments of the present invention, a plurality of support columns 600 are provided between the first connecting part 104 and the second connecting part 204, and the two ends of the support columns 600 are respectively connected to the first connecting part 104 and the second connecting part 204.

[0069] In this configuration, multiple support columns 600 are sequentially arranged along the length direction of the first protrusion 103 and the second protrusion 203, and there is a preset distance between any two adjacent support columns 600 to facilitate the passage of the phase change medium 300. This arrangement allows the phase change medium 300 to pass between any two support columns 600.

[0070] The embodiments of the present invention do not limit the specific type of phase change medium 300. Any structure that meets the requirements of the present invention is within the protection scope of the present invention.

[0071] As a preferred embodiment, the phase change medium 300 disclosed in this embodiment of the invention can be water, acetone, or Freon.

[0072] As a preferred embodiment, the heat transfer coefficient of the bipolar plate disclosed in this embodiment of the invention is 5000W / mK-10000W / mK.

[0073] This invention also discloses a fuel cell stack, please refer to... Figure 14 The bipolar plate structure disclosed in any of the above embodiments includes membrane electrodes 700 and multiple bipolar plates and membrane electrodes 700, wherein any membrane electrode 700 is disposed between any two adjacent bipolar plates.

[0074] In this process, the membrane electrode 700 and the bipolar plate undergo an electrochemical reaction under the action of the reactant gas to generate current and heat. The heat is transferred from the inside of the fuel cell to the outside through the absorption and release of the latent heat of phase change, thereby reducing the internal temperature of the fuel cell.

[0075] Since the above-mentioned fuel cell stack adopts the above-mentioned bipolar plate structure, the above-mentioned fuel cell stack also has the technical advantages of the above-mentioned bipolar plate structure. The embodiments of the present invention will not elaborate on these advantages in detail.

[0076] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0077] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0078] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bipolar plate structure, characterized in that, The device includes an anode plate, a cathode plate, a capillary wick, and a phase change medium. The anode plate and the cathode plate are connected to form a vacuum-sealed cavity. The capillary wick is disposed on the inner wall of the vacuum-sealed cavity, and the phase change medium is filled in the vacuum-sealed cavity. The bipolar plate includes a heating area and a heat dissipation area. The heating area is located at one end of the bipolar plate, and the heat dissipation area is located at the other end of the bipolar plate. The phase change medium can absorb the heat from the heating area and transfer the heat to the heat dissipation area, thereby dissipating the heat. The anode plate is provided with a plurality of strip-shaped first protrusions, and the cathode plate is provided with a plurality of second protrusions corresponding to the first protrusions. The protrusion directions of the first protrusions and the second protrusions are opposite. The first protrusions and the second protrusions cooperate to form a cylindrical cavity, and the phase change medium can flow in the cylindrical cavity in a direction perpendicular to its axis. A first connecting portion is provided between any two adjacent first protrusions, and a second connecting portion corresponding to the first connecting portion is provided between any two adjacent second protrusions; The first connecting part is a first groove, and the second connecting part is a second groove. The bottom of the first groove and the top of the second groove are in contact. The first groove is provided with a first through hole for the phase change medium to pass through, and the second groove is provided with a second through hole for the phase change medium to pass through.

2. The bipolar plate structure according to claim 1, characterized in that, The anode plate includes a first surface and a second surface, and the cathode plate includes a third surface and a fourth surface, the second surface and the fourth surface forming the inner wall of the vacuum-sealed cavity.

3. The bipolar plate structure according to claim 2, characterized in that, The heating area includes a first heating area disposed on the anode plate and a second heating area disposed on the cathode plate; The heat dissipation area includes a first heat dissipation area disposed on the anode plate and a second heat dissipation area disposed on the cathode plate.

4. The bipolar plate structure according to claim 3, characterized in that, The first heat dissipation area is provided with a plurality of first convex cavities, and the first convex cavities protrude in the direction of the second surface.

5. The bipolar plate structure according to claim 4, characterized in that, The second heating area is provided with a plurality of second convex cavities and third convex cavities, the second convex cavities and the third convex cavities being arranged at intervals; The second convex cavity and the third convex cavity protrude in opposite directions; the second convex cavity protrudes toward the third surface, and the third convex cavity protrudes toward the fourth surface. A fourth convex cavity is provided on the second heat dissipation area, and the fourth convex cavity protrudes in the direction of the fourth surface.

6. The bipolar plate structure according to claim 1, characterized in that, The liquid inlet of the anode plate is located on one side parallel to the axis of the cylindrical cavity, and the liquid inlet of the cathode plate is located on one side perpendicular to the axis of the cylindrical cavity.

7. The bipolar plate structure according to claim 1, characterized in that, The first connecting part is stamped with a plurality of support blocks, the bottom end face of the support blocks is connected to the second connecting part, and there is a gap between any two connected support blocks for the phase change medium to pass through.

8. The bipolar plate structure according to claim 1, characterized in that, A plurality of support columns are provided between the first connecting part and the second connecting part, and the two ends of the support columns are respectively connected to the first connecting part and the second connecting part; The multiple support columns are arranged sequentially along the length direction of the first protrusion and the second protrusion, and there is a preset distance between any two adjacent support columns to facilitate the passage of the phase change medium.

9. A fuel cell stack, characterized in that, It includes a membrane electrode and a bipolar plate structure as described in any one of claims 1-8; There are multiple bipolar plates and multiple membrane electrodes, and any one of the membrane electrodes is disposed between any two adjacent bipolar plates.

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