Cathode open type air-cooled fuel cell bipolar plate assembly and fuel cell

Abstract

The invention discloses a cathode open type air-cooled fuel cell bipolar plate assembly and a fuel cell, and relates to the technical field of fuel cells. Wherein the bipolar plate assembly comprises a single-layer bipolar plate. The bipolar plate comprises a first end, a second end and a wave section, and the first end and the second end are connected to the two ends of the wave section in the length direction respectively. The wave trough of the anode side of the wave section is an anode groove, the wave trough of the cathode side of the wave section is a cathode groove, and the anode groove and the cathode groove both extend to the two ends of the wave section in the width direction. The edge of the anode side of the bipolar plate is used for being in sealing contact with a cavity so that the anode grooves can be communicated with one another. The first end is provided with a gas inlet used for supplying hydrogen into the cavity, and the second end is provided with a gas outlet used for discharging gas in the cavity. According to the invention, the anode tank and the cathode tank are integrated on one plate, so that the overall weight is reduced, the mold development cost and the coating cost are reduced, the problems of contact thermal resistance and resistance increase are avoided, and the heat dissipation efficiency and performance of the fuel cell can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a cathode open air-cooled fuel cell bipolar plate assembly and a fuel cell. Background Art

[0002] As a highly efficient energy conversion device, fuel cells can use hydrogen and oxygen as reaction gases to convert the chemical energy of fuel into electrical energy through electrochemical reactions. The cathode open air-cooled fuel cell is a fuel cell that uses a fan to achieve oxygen supply and heat dissipation functions. It is mainly suitable for occasions with small power requirements, such as drones, mobile power supplies, etc., and its power range is usually between 10 W and 5 kW. Its structure is mainly composed of end plates, bipolar plates, membrane electrode assemblies, electrical connectors, fasteners and seals. The core component of the air-cooled fuel cell is the membrane electrode, which is used for electrochemical reactions. The bipolar plate is the "skeleton" of the battery, which is stacked and assembled with the membrane electrode to provide reactants to the electrodes, and plays the role of supporting the fuel cell, collecting current, providing channels, and separating different reactants.

[0003] The existing air-cooled fuel cell bipolar plate includes an anode plate and a cathode plate, which are stacked up and down. The end face of the anode plate is provided with an anode flow field, and the anode flow field is provided with an anode flow channel with two ends opened along the long side of the battery for hydrogen to enter and exit; the end face of the cathode plate is provided with a cathode flow field, and the cathode flow field is provided with a cathode flow channel with two ends opened along the short side of the battery for air to enter and exit, and the anode flow channel and the cathode flow channel are perpendicular. This bipolar plate has the following disadvantages: 1. The anode plate and the cathode plate are usually assembled by laser welding or pressing, which may cause cold welding or partial displacement of the bipolar plate due to pressure, resulting in increased contact thermal resistance and electrical resistance of the bipolar plate, and reduced heat dissipation efficiency and performance of the battery.

[0004] 2. The bipolar plate accounts for 60% to 80% of the total weight of the fuel cell and 50% to 65% of the total volume of the battery, which is not conducive to meeting the application requirements of lightweight and small-volume drones.

[0005] 3. The development cost of bipolar plate molds is high, and the metal bipolar plate coating process cost is high. Summary of the invention

[0006] The purpose of the present invention is to provide a cathode open air-cooled fuel cell bipolar plate assembly and a fuel cell, which effectively reduce the body resistance of the bipolar plate and the contact resistance and thermal resistance caused by laser welding, thereby improving the heat dissipation performance and overall electrochemical performance of the fuel cell.

[0007] To achieve the above object, the present invention provides the following solutions: The present invention discloses a cathode open air-cooled fuel cell bipolar plate assembly, comprising a bipolar plate, wherein the bipolar plate is a single-layer plate; the bipolar plate comprises a first end, a second end and a wave section, wherein the first end and the second end are respectively connected to two ends of the wave section in a length direction; The trough on the anode side of the wave segment is an anode slot, and the trough on the cathode side of the wave segment is a cathode slot, and both the anode slot and the cathode slot extend to both ends of the wave segment in the width direction; The edge of the anode side of the bipolar plate is used to seal and contact with a cavity so that multiple anode slots are interconnected; the first end is provided with an inlet for supplying hydrogen into the cavity, and the second end is provided with an outlet for discharging gas in the cavity.

[0008] Preferably, the anode slot and the cathode slot are straight slots, and the extension direction of the straight slots is parallel to the width direction of the wave segment.

[0009] Preferably, the cavity comprises a sealing ring, the edge of the anode side of the bipolar plate is in sealing contact with the sealing ring, and a through hole is provided on the sealing ring at a position directly opposite to the air inlet and the air outlet.

[0010] Preferably, the first end and the second end both have a first edging, and both ends of the sealing ring in the length direction and the width direction are against the first edging; the edges of the air inlet and the air outlet have a second edging, and the second edging is used to contact and position with the corresponding through holes on the sealing ring.

[0011] Preferably, the number of the air inlet and the number of the air outlet are both plural.

[0012] Preferably, the plurality of air inlets and the plurality of air outlets are arranged along a straight line, and the straight line is parallel to the width direction of the wave segment.

[0013] Preferably, the cavity further comprises an annular gasket, which is located on a side of the sealing ring away from the bipolar plate and is used to press the sealing ring toward the bipolar plate.

[0014] Preferably, the annular gasket is made of metal or polymer material.

[0015] Preferably, the anode slot and the cathode slot are both rectangular slots, the slot width of the rectangular slot is 1.5-2 mm, and the slot depth of the rectangular slot is 1.5-2 mm.

[0016] The present invention also discloses a fuel cell, comprising the above-mentioned cathode open air-cooled fuel cell bipolar plate assembly.

[0017] Compared with the related art, the present invention has achieved the following technical effects: In this embodiment, the anode tank and the cathode tank are integrated into one plate, and there is no need to overlap the anode plate and the cathode plate. On the basis of ensuring the performance, the overall weight is reduced to achieve a lightweight design.

[0018] After hydrogen enters the cavity from the air inlet, its flow path in the cavity is wavy, which increases the gas pressure in the flow field and improves the electrochemical performance of the fuel cell.

[0019] Due to the simplification of structure and reduction in the number of parts, the need for complex molds is reduced, the coating area of ​​the surface coating is reduced, and the mold development cost and coating cost are reduced.

[0020] Since there is no need to assemble the anode plate and the cathode plate by laser welding or compression, the problem of increased contact thermal resistance and electrical resistance is avoided, thereby ensuring the heat dissipation efficiency and performance of the fuel cell.

[0021] In the preferred embodiment of the present invention, the close fit between the annular gasket and the sealing ring, and the contact and limiting between the sealing ring and the first and second edge wraps respectively, ensure that the sealing element is not easily displaced during the assembly process. In addition, the close fit between the annular gasket and the sealing ring is used to evenly distribute the assembly pressure, prevent local over-tightening or over-loosening assembly problems, thereby reducing the risk of gas leakage and improving the sealing performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the assembly relationship of a bipolar plate assembly of an open cathode air-cooled fuel cell according to an embodiment of the present invention; Figure 2 is a front view of a bipolar plate; Figure 3 is a top view of a bipolar plate; Figure 4 A partial schematic diagram of a bipolar plate assembly of an air-cooled fuel cell with an open cathode according to an embodiment of the present invention; Figure 5 It is a schematic diagram of a straight-line hemming; Figure 6 This is a schematic diagram of the second edge wrapping; Figure 7 This is a schematic diagram of wave-type edging 1.

[0024] In the figure: 1-bipolar plate; 2-sealing ring; 3-ring gasket; 4-protrusion; 5-air inlet; 6-air outlet; 7-flow direction of hydrogen on the anode side; 8-flow direction of air on the cathode side; 9-edge wrapping one; 10-edge wrapping two. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a cathode open air-cooled fuel cell bipolar plate assembly and a fuel cell, which effectively reduce the body resistance of the bipolar plate and the contact resistance and thermal resistance caused by laser welding, thereby improving the heat dissipation performance and overall electrochemical performance of the fuel cell.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figure 1 to Figure 7 The present embodiment provides a cathode open air-cooled fuel cell bipolar plate assembly, including a bipolar plate 1, which is a single-layer plate. The bipolar plate 1 includes a first end, a second end and a wave section, and the first end and the second end are respectively connected to the two ends of the length direction of the wave section.

[0029] The trough on the anode side of the wave segment is the anode slot, and the trough on the cathode side of the wave segment is the cathode slot. The anode slot and the cathode slot both extend to both ends of the width direction of the wave segment. The length direction of the wave segment is the length direction of the bipolar plate 1, and the width direction of the wave segment is the width direction of the bipolar plate 1.

[0030] The edge of the anode side of the bipolar plate 1 is used to seal with a cavity so that multiple anode tanks are interconnected. The first end is provided with an inlet 5 for supplying hydrogen into the cavity, and the second end is provided with an outlet 6 for exhausting gas in the cavity.

[0031] The working principle of the cathode open air-cooled fuel cell bipolar plate assembly of this embodiment is as follows: The bipolar plate 1 of this embodiment has a wave section, and utilizing the wave shape of the wave section, an anode slot and a cathode slot are formed on the anode side and the cathode side of the bipolar plate 1, respectively. Hydrogen enters the cavity from the air inlet 5 and flows along the length direction of the wave section, providing a continuous fuel supply for the electrochemical reaction, and excess hydrogen and reaction by-products are discharged from the air outlet 6. Air enters from one end of the cathode slot and flows along the width direction of the wave section, providing oxygen to participate in the reaction, while taking away part of the heat and water generated by the reaction, and excess air and water generated by the reaction are discharged from the other end of the cathode slot.

[0032] In this embodiment, the anode tank and the cathode tank are integrated into one plate, and there is no need to overlap the anode plate and the cathode plate. On the basis of ensuring the performance, the overall weight is reduced to achieve a lightweight design.

[0033] After the hydrogen enters the cavity from the gas inlet 5, the flow path in the cavity is wavy, which increases the gas pressure in the flow field and improves the electrochemical performance of the fuel cell.

[0034] Due to the simplification of structure and reduction in the number of parts, the need for complex molds is reduced, the coating area of ​​the surface coating is reduced, and the mold development cost and coating cost are reduced.

[0035] Furthermore, since there is no need to assemble the anode plate and the cathode plate by laser welding or compression, the problem of increased contact thermal resistance and electrical resistance is avoided, thereby ensuring the heat dissipation efficiency and performance of the fuel cell.

[0036] As a possible example, in this embodiment, the anode slot and the cathode slot are straight slots, and the extension direction of the straight slot is parallel to the width direction of the wave segment.

[0037] It can be understood that the anode slot and the cathode slot can also be straight slots that form a certain angle with the width direction of the wave section; the anode slot and the cathode slot can also be curved slots, in which case both extend in a curve.

[0038] As a possible example, in this embodiment, the cavity includes a sealing ring 2, the edge of the anode side of the bipolar plate 1 is in sealing contact with the sealing ring 2, and a through hole is provided on the sealing ring 2 at a position opposite to the air inlet 5 and the air outlet 6.

[0039] It can be understood that the side of the sealing ring 2 that contacts the wave segment is a wavy surface that is consistent with the shape of the wave segment, so as to achieve close contact with the wave segment.

[0040] Exemplarily, the cross-sections of the anode tank and the cathode tank are both square; the sealing ring 2 includes a substrate and a protrusion 4, the protrusion 4 is fixedly connected to the side of the substrate facing the wave section, and is used to extend into one end of the anode tank and contact and seal with the bottom and side walls of the anode tank; the cross-section of the protrusion 4 is square.

[0041] As a possible example, in this embodiment, refer to Figure 5 , Figure 7 The first end and the second end both have a rim 9 , and both ends of the sealing ring 2 in the length direction and the width direction are against the rim 9 .

[0042] The edge 9 of the bipolar plate 1 is used to limit the sealing ring 2 to prevent the sealing ring 2 from sliding and staggering with the bipolar plate 1, thereby ensuring the sealing and avoiding hydrogen leakage.

[0043] The type of hemming can be flexibly selected, such as straight line type (refer to Figure 5 ) and wavy (ref. Figure 7 ). For bipolar plates with a larger width, the edge wrapping 9 is set to be wavy to reduce deformation caused by stress and prevent leakage.

[0044] As a possible example, in this embodiment, the number of the air inlet 5 and the number of the air outlet 6 are both plural.

[0045] Exemplarily, there are three air inlets 5 and three air outlets 6, and two adjacent air inlets 5 and two adjacent air outlets 6 are separated by ribs. If the ribs are removed, the multiple air inlets 5 and the multiple air outlets 6 form a rectangular hole with rounded corners.

[0046] For example, the rectangular hole with rounded corners has a length of 40 mm and a width of 4 mm. The rib has a width of 1 mm and a length of 4 mm (the width direction of the rib is the length direction of the rectangular hole with rounded corners).

[0047] As a possible example, in this embodiment, refer to Figure 6 On the bipolar plate 1, the edges of the air inlet 5 and the air outlet 6 have a rim 10, which is used to contact and position with the corresponding through holes on the sealing ring 2 to prevent the sealing ring 2 from sliding and staggering with the bipolar plate 1, thereby ensuring the sealing performance and avoiding hydrogen leakage.

[0048] Exemplarily, the thickness of the first edge 9 and the second edge 10 is consistent with the thickness of the bipolar plate 1 , and the height of the first edge 9 and the second edge 10 is 0.1-0.5 mm.

[0049] As a possible example, in this embodiment, the plurality of air inlets 5 and the plurality of air outlets 6 are arranged along a straight line, and the straight line is parallel to the width direction of the wave segment.

[0050] This arrangement enables the hydrogen on the anode side to be more evenly distributed in the width direction of the bipolar plate 1, thereby improving the power generation efficiency of the fuel cell.

[0051] As a possible example, in this embodiment, the cavity further includes an annular gasket 3 , which is located on a side of the sealing ring 2 away from the bipolar plate 1 and is used to press the sealing ring 2 toward the bipolar plate 1 .

[0052] Exemplarily, the outer contours of the annular gasket 3 , the sealing ring 2 and the bipolar plate 1 are the same.

[0053] The close fit between the annular gasket 3 and the sealing ring 2 ensures that the sealing element is not easily displaced during the assembly process, and evenly distributes the assembly pressure to prevent local over-tightening or over-loosening of the assembly, thereby reducing the risk of gas leakage and improving the sealing performance of the fuel cell.

[0054] It should be noted that if the sealing components are improperly installed, aged, or mechanically damaged during assembly, gas leakage may occur, especially in high temperature, high pressure or vibration environments. Such leakage not only reduces the efficiency of the fuel cell, but may also threaten the safety of the fuel cell.

[0055] In this embodiment, the bipolar plate 1 and the sealing ring 2 are mutually limited by the arrangement of the first edge 9 and the second edge 10, thereby ensuring the position stability of the sealing ring 2; and the sealing ring 2 is uniformly pressed by the annular gasket 3 to ensure the fit between the sealing ring 2 and the bipolar plate 1. Therefore, this embodiment can solve the problem of unstable sealing performance of the sealing element in the prior art.

[0056] As a possible example, in this embodiment, the bipolar plate 1 is made of metal or graphite, and the annular gasket 3 is made of metal or polymer material.

[0057] Exemplarily, the metal material here may be stainless steel, aluminum alloy, etc., and the polymer material may be polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.

[0058] As a possible example, in this embodiment, both the anode slot and the cathode slot are rectangular slots, the slot width of the rectangular slot is 1.5-2 mm, and the slot depth of the rectangular slot is 1.5-2 mm.

[0059] This embodiment also provides a fuel cell, including the above-mentioned cathode open air-cooled fuel cell bipolar plate assembly.

[0060] Since the fuel cell includes the above-mentioned cathode open air-cooled fuel cell bipolar plate assembly, it also has the corresponding advantages of the cathode open air-cooled fuel cell bipolar plate assembly, which will not be repeated here.

[0061] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A cathode open air-cooled fuel cell bipolar plate assembly, characterized in that: The bipolar plate comprises a single-layer plate, wherein the bipolar plate comprises a first end, a second end and a wave segment, wherein the first end and the second end are respectively connected to two ends of the wave segment in a length direction; The trough on the anode side of the wave segment is an anode slot, and the trough on the cathode side of the wave segment is a cathode slot, and both the anode slot and the cathode slot extend to both ends of the wave segment in the width direction; The edge of the anode side of the bipolar plate is used to seal and contact with a cavity so that multiple anode slots are interconnected; the first end is provided with an inlet for supplying hydrogen into the cavity, and the second end is provided with an outlet for discharging gas in the cavity.

2. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 1, characterized in that: The anode slot and the cathode slot are straight slots, and the extension direction of the straight slots is parallel to the width direction of the wave segment.

3. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 1, characterized in that: The cavity comprises a sealing ring, the edge of the anode side of the bipolar plate is in sealing contact with the sealing ring, and a through hole is arranged on the sealing ring at a position directly opposite to the air inlet and the air outlet.

4. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 3, characterized in that: The first end and the second end both have a first edging, and both ends of the sealing ring in the length direction and the width direction are against the first edging; the edges of the air inlet and the air outlet have a second edging, and the second edging is used to contact and position with the corresponding through holes on the sealing ring.

5. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 1, characterized in that: The number of the air inlet and the number of the air outlet are both multiple.

6. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 5, characterized in that: The plurality of air inlets and the plurality of air outlets are arranged along a straight line, and the straight line is parallel to the width direction of the wave segment.

7. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 3, characterized in that: The cavity further comprises an annular gasket, which is located at a side of the sealing ring away from the bipolar plate and is used to press the sealing ring toward the bipolar plate.

8. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 7, characterized in that: The annular gasket is made of metal or polymer material.

9. The cathode open air-cooled fuel cell bipolar plate assembly according to claim 1, characterized in that: The anode slot and the cathode slot are both rectangular slots, the slot width of the rectangular slot is 1.5-2 mm, and the slot depth of the rectangular slot is 1.5-2 mm.

10. A fuel cell, characterized in that: It comprises a cathode open air-cooled fuel cell bipolar plate assembly as described in any one of claims 1 to 9.

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