Air-cooled hydrogen fuel cell bipolar plate, single cell, electric pile and preparation method

Abstract

The invention discloses an air-cooled hydrogen fuel cell bipolar plate, a single cell, an electric pile and a preparation method, and belongs to the technical field of air-cooled hydrogen fuel cells. The bipolar plate comprises a plate body, a first groove is formed in one side face of the plate body, a cathode runner is arranged in the first groove, a second groove is formed in the other side face of the plate body, an anode runner is arranged in the second groove, and an air inlet and an air outlet are formed in the two ends of the plate body respectively. And the air inlet and the air outlet are respectively communicated with two ends of the anode runner. The cathode flow channel adopts a parallel flow channel; and the anode runner adopts a snakelike runner. The anode flow channel and the cathode flow channel of the bipolar plate are both arranged in the sunken groove, and the compression amount of the gas diffusion layer is controlled according to the depth of the groove; according to the structure, the problem that a gas diffusion layer in a traditional membrane battery is prone to overpressure can be effectively prevented, so that the diffusion rate and uniformity of hydrogen and oxygen between the membrane electrodes are improved, and the response speed and the output performance of the single-frame membrane electrode are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air-cooled hydrogen fuel cells, and in particular to an air-cooled hydrogen fuel cell bipolar plate, a single cell, a fuel cell stack and a preparation method thereof. Background Art

[0002] Hydrogen fuel cells are a clean energy technology that converts hydrogen and oxygen into electricity through an electrochemical reaction, with water vapor being the only emission. Promoting hydrogen energy technology can boost the use of renewable energy, reduce reliance on traditional energy sources, and thus alleviate environmental pressures. Furthermore, hydrogen fuel cells offer high energy conversion efficiency compared to traditional combustion power generation and internal combustion engine systems.

[0003] Hydrogen fuel cell membrane electrodes are key components of fuel cells. Continuous improvements to membrane electrodes can enhance the efficiency, stability, and lifespan of hydrogen fuel cells, promoting their application in renewable and clean energy. Water-cooled reactor membrane electrodes require additional water cooling systems, including water pumps, chillers, and other equipment, increasing system complexity and cost, as well as the difficulty of operation and maintenance. Furthermore, water-cooled reactors carry the risk of water leaks, which could damage equipment or pose safety hazards. Air-cooled reactor membrane electrodes avoid these drawbacks of water-cooled reactors, offering greater flexibility and adaptability.

[0004] Current air-cooled membrane electrodes, such as the seven-in-one membrane electrode, have numerous components and a complex packaging process, requiring specialized equipment and technology. This has hindered large-scale production of membrane electrodes. Furthermore, the relatively thick frames of existing air-cooled membrane electrodes affect the heat transfer efficiency of hydrogen fuel cells. The carbon paper used in existing air-cooled membrane electrodes also suffers from overvoltage issues, which, when combined with the thick frames, impacts the efficiency and lifespan of hydrogen fuel cells. Summary of the Invention

[0005] Based on the above technical problems, the present invention proposes an air-cooled hydrogen fuel cell bipolar plate, a single cell, a fuel cell stack and a preparation method.

[0006] The technical solution adopted by the present invention is:

[0007] A bipolar plate for an air-cooled hydrogen fuel cell includes a plate body, a first groove is provided on one side of the plate body, a cathode flow channel is arranged in the first groove, a second groove is provided on the other side of the plate body, an anode flow channel is arranged in the second groove, and an air inlet and an air outlet are respectively provided at both ends of the plate body, and the air inlet and the air outlet are respectively connected to the two ends of the anode flow channel.

[0008] Preferably, the cathode flow channel adopts a parallel flow channel; the anode flow channel adopts a serpentine flow channel.

[0009] Preferably, the plate body is rectangular, and the arrangement direction of the parallel flow channels is perpendicular to the extension direction of the plate body; the main flow direction of the serpentine flow channel is consistent with the extension direction of the plate body.

[0010] Preferably, the serpentine flow channels are arranged in several groups, and the main body of each group of serpentine flow channels occupies a certain area of ​​the second groove.

[0011] Preferably, a sealing groove is provided around the circumference of the second groove.

[0012] Preferably, the groove depth of the first groove is 110-170 μm, more preferably 120-160 μm, and the groove depth of the second groove is 100-160 μm, more preferably 110-150 μm; the height of the cathode flow channel is less than the groove depth of the first groove, and the height of the anode flow channel is less than the groove depth of the second groove.

[0013] A single cell employing the bipolar plate described above, specifically further comprising a CCM membrane electrode, a membrane electrode frame, a first gas diffusion layer, and a second gas diffusion layer; a rectangular opening adapted for the CCM membrane electrode being provided at the center of the membrane electrode frame; the CCM membrane electrode being fixed to the membrane electrode frame, the first gas diffusion layer being bonded to one side of the CCM membrane electrode, and the second gas diffusion layer being bonded to the other side of the CCM membrane electrode; one bipolar plate being provided on one side of the membrane electrode frame, and the first gas diffusion layer being positioned in a first groove of the bipolar plate after lamination; and the other bipolar plate being provided on the other side of the membrane electrode frame, and the second gas diffusion layer being positioned in a second groove of the bipolar plate after lamination.

[0014] Preferably, the first gas diffusion layer and the second gas diffusion layer are both made of carbon paper, the thickness of the carbon paper is 150-260 μm, more preferably 180-250 μm, and the compression amount is 15-40%, more preferably 20-35%.

[0015] A battery stack is provided, which adopts a stacked arrangement of several single cells as described above, and the upper and lower adjacent single cells share a bipolar plate.

[0016] The method for preparing the above-mentioned battery stack comprises the following steps:

[0017] (1) Coating a cathode catalyst layer and an anode catalyst layer on both sides of a proton exchange membrane to obtain a CCM membrane electrode;

[0018] (2) overlapping the anode catalyst layer of the CCM membrane electrode with the rectangular opening area in the center of the membrane electrode frame, and directly bonding the membrane electrode frame to the proton exchange membrane of the CCM membrane electrode;

[0019] (3) The bipolar plates are formed by integrated stamping, and after etching and grooving, the cathode and anode channels are machined by CNC cutting;

[0020] (4) placing a first gas diffusion layer between the membrane electrode frame and the second groove of one of the bipolar plates, and bonding the first gas diffusion layer to the membrane electrode frame; placing a second gas diffusion layer between the CCM membrane electrode and the first groove of the other bipolar plate, and bonding the second gas diffusion layer to the CCM membrane electrode;

[0021] (5) Pressing the two bipolar plates together with the first gas diffusion layer, the membrane electrode frame, the CCM membrane electrode, and the second gas diffusion layer therebetween to form a single cell;

[0022] (6) Several single cells are stacked up and down, and the upper and lower adjacent single cells share a bipolar plate to form an air-cooled hydrogen fuel cell stack.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] (1) The anode and cathode flow channels of the integrated air-cooled bipolar plate described in the present invention are both arranged in the sunken grooves, and the compression of the gas diffusion layer is controlled according to the groove depth; this structure can effectively prevent the problem of easy overpressure of the gas diffusion layer in traditional membrane batteries, thereby improving the diffusion rate and uniformity of hydrogen and oxygen between the membrane electrodes, and further improving the response speed and output performance of the single-frame membrane electrode.

[0025] (2) The membrane electrode frame of the present invention does not need to prevent overpressure in the gas diffusion layer. Therefore, compared with traditional membrane electrode, the thickness of the frame can be greatly reduced. The thinner frame can more effectively transfer heat during fuel cell operation, improve the efficiency and life of the fuel cell, and help reduce manufacturing costs and improve production efficiency and processing accuracy.

[0026] (3) The membrane electrode structure of the present invention requires only a single frame. Combined with the bipolar plate structure described above, this reduces the number of components and assembly steps, lowering manufacturing costs. Furthermore, it effectively reduces electrode voltage drop and gas diffusion resistance, improving battery performance and efficiency. This structure also reduces contact resistance between the frames, improving the battery's electrical conductivity.

[0027] (4) The integrated air-cooled stack described in the present invention does not require mold casting, which greatly reduces the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of one side of the air-cooled hydrogen fuel cell bipolar plate of the present invention;

[0029] Figure 2 This is a schematic structural diagram of the other side of the air-cooled hydrogen fuel cell bipolar plate of the present invention;

[0030] Figure 3 This is an exploded view of the structure of the air-cooled hydrogen fuel cell of the present invention;

[0031] Figure 4 The membrane electrode performance diagram obtained by the specific embodiment of the present invention and the comparative example;

[0032] Figure 5 The graphs are for the performance of the battery stacks obtained for the specific embodiments and comparative examples of the present invention.

[0033] In the figure: 1-plate, 2-first groove, 3-cathode flow channel, 4-second groove, 5-anode flow channel, 6-air inlet, 7-air outlet, 8-sealing groove, 9-CCM membrane electrode, 10-membrane electrode frame, 11-first gas diffusion layer, 12-second gas diffusion layer, 13-rectangular opening;

[0034] 501 - first serpentine flow channel, 502 - second serpentine flow channel, 503 - third serpentine flow channel. DETAILED DESCRIPTION

[0035] like Figure 1-2 As shown, a bipolar plate for an air-cooled hydrogen fuel cell includes a plate body 1. A first groove 2 is provided on one side of the plate body 1, and a cathode flow channel 3 is arranged in the first groove 2. A second groove 4 is provided on the other side of the plate body 1, and an anode flow channel 5 is arranged in the second groove 4. An air inlet 6 and an air outlet 7 are provided at both ends of the plate body 1, respectively, and the air inlet 6 and the air outlet 7 are respectively connected to the two ends of the anode flow channel 5.

[0036] The cathode flow channel 3 is a parallel flow channel; the anode flow channel 5 is a serpentine flow channel. Specifically, the plate body 1 is rectangular, and the arrangement direction of the parallel flow channels is perpendicular to the extension direction of the plate body 1. The main flow direction of the serpentine flow channel is consistent with the extension direction of the plate body. More specifically, the serpentine flow channels are arranged in several groups, and the main body of each group of serpentine flow channels occupies a certain area of ​​the second groove 4. Figure 2 As shown, there are three groups of serpentine flow channels, namely a first serpentine flow channel 501 located at both ends of the second groove 4, a second serpentine flow channel 502, and a third serpentine flow channel 503 located in the middle of the second groove 4.

[0037] A sealing groove 8 is further provided around the second groove 4. A sealing member may be placed in the sealing groove 8 to seal during pressing to prevent the gas flowing through the anode flow channel 5 from leaking out.

[0038] The first groove 2 has a depth of 120-160 μm, and the second groove 4 has a depth of 110-150 μm. The height of the cathode flow channel 3 is less than the depth of the first groove 2, and the height of the anode flow channel 5 is less than the depth of the second groove 4. The difference between the flow channel height and the groove depth is used for the subsequent pressing of the gas diffusion layer.

[0039] During use, hydrogen enters the air-cooled hydrogen fuel cell bipolar plate through the air inlet 6, flows through the anode flow channel 5, and exits through the air outlet. Air is drawn in from the outside and flows along the parallel flow channel, namely the cathode flow channel 3. This ensures that hydrogen and air flow and distribution are respectively maintained on both sides of the CCM membrane electrode.

[0040] The membrane electrode is suitable for proton exchange membrane (PEM) fuel cells and can solve the problem of difficulty in controlling the compression volume of single-frame membrane electrodes while reducing system complexity and cost.

[0041] The bipolar plate flow channel area is grooved, and the compression of the carbon paper is controlled by the groove depth. The membrane electrode frame does not need to control the compression of the carbon paper, so the thickness of the membrane electrode frame is much lower than that of an ordinary frame.

[0042] like Figure 3 As shown, a single cell employing the bipolar plate described above further includes a CCM membrane electrode 9, a membrane electrode frame 10, a first gas diffusion layer 11, and a second gas diffusion layer 12. A rectangular opening 13 is provided in the center of the membrane electrode frame 10 to accommodate the CCM membrane electrode 9. The CCM membrane electrode 9 is fixed to the membrane electrode frame 10, the first gas diffusion layer 11 is bonded to one side of the CCM membrane electrode 9, and the second gas diffusion layer 12 is bonded to the other side of the CCM membrane electrode 9. One of the bipolar plates is disposed on one side of the membrane electrode frame 10, and after lamination, the first gas diffusion layer 11 is positioned in the first groove 2 of the bipolar plate. The other bipolar plate is disposed on the other side of the membrane electrode frame 10, and after lamination, the second gas diffusion layer 12 is positioned in the second groove 4 of the bipolar plate.

[0043] The first gas diffusion layer 11 and the second gas diffusion layer 12 are both made of carbon paper with a thickness of 180-250 μm and a compression amount of 20-35%.

[0044] The present invention also provides a battery stack, which adopts a stacked arrangement of a plurality of single cells as described above, and the upper and lower adjacent single cells share a bipolar plate.

[0045] The method for preparing the above-mentioned battery stack comprises the following steps:

[0046] (1) A cathode catalyst layer and an anode catalyst layer are coated on both sides of the proton exchange membrane to obtain a CCM membrane electrode.

[0047] (2) The anode catalyst layer of the CCM membrane electrode is overlapped with the rectangular opening area in the center of the membrane electrode frame, and the membrane electrode frame is directly bonded to the proton exchange membrane of the CCM membrane electrode.

[0048] (3) The bipolar plates are formed by integrated stamping. After etching and grooving, the cathode flow channel and the anode flow channel are processed by CNC cutting.

[0049] (4) A first gas diffusion layer is placed between the membrane electrode frame and the second groove of one of the bipolar plates, and the first gas diffusion layer is bonded to the membrane electrode frame; a second gas diffusion layer is placed between the CCM membrane electrode and the first groove of the other bipolar plate, and the second gas diffusion layer is bonded to the CCM membrane electrode.

[0050] (5) Press the two bipolar plates together with the first gas diffusion layer, membrane electrode frame, CCM membrane electrode and second gas diffusion layer between them to form a single cell.

[0051] (6) Several single cells are stacked up and down, and the upper and lower adjacent single cells share a bipolar plate to form an air-cooled hydrogen fuel cell stack.

[0052] In summary, the present invention provides a high-efficiency air-cooled hydrogen fuel cell stack. The integrated air-cooled hydrogen fuel cell bipolar plate used includes an anode flow channel and a cathode flow channel, wherein the flow field adopts a sunken groove design, and a gas flow channel is provided on the surface of the groove area, and a gas diffusion layer such as carbon paper can be placed in the groove. The anode flow channel where the carbon paper is placed is laminated to the single-frame membrane electrode; after the carbon paper is placed in the cathode flow channel area, it is laminated to the integrated single-frame membrane electrode. The design depth of the grooves of the anode and cathode plates is consistent with the thickness of the carbon paper after the optimal compression amount, which can effectively prevent overpressure. The single-frame integrated membrane electrode structure design proposed in the present invention can significantly reduce the thickness of the stack, save costs, and at the same time ensure that the stack achieves optimal performance.

[0053] In the stack of the present invention, only the membrane electrode anode has a membrane electrode frame, and the membrane electrode frame is thinner than a conventional frame. The central rectangular area of ​​the membrane electrode frame overlaps the anode catalyst layer, and the membrane electrode frame is directly bonded to the proton exchange membrane anode using an adhesive.

[0054] During the preparation method, the carbon paper can be further hydrophilized. For example, it can be treated with anhydrous ethanol, ammonia, formaldehyde, and tetraethyl orthosilicate solution for 24 hours, followed by surface modification with concentrated nitric acid, ultimately yielding carbon paper with excellent hydrophilicity. The first gas diffusion layer 11 is bonded to the anode catalyst layer of the CCM membrane electrode via an adhesive, and the second gas diffusion layer 12 is bonded to the cathode catalyst layer of the CCM membrane electrode via an adhesive.

[0055] Furthermore, the proton exchange membrane can utilize a perfluorosulfonic acid membrane. The catalyst layer slurry includes a Pt / C catalyst, a perfluorosulfonic acid resin, carbon nanotubes, a solvent, and deionized water. The catalyst layer slurry is deaerated using a degassing machine before coating. The anode catalyst layer is applied using a direct coating method. The cathode catalyst layer is applied using an intermittent coating method, with several equally spaced rectangular coating areas applied to the proton exchange membrane.

[0056] The CCM anode catalyst layer overlaps with the central rectangular area of ​​the membrane electrode frame, and the adhesive surface of the membrane electrode frame is directly bonded to the proton exchange membrane of the CCM. The membrane electrode frame uses a single-layer polyamide or polyester material. A first gas diffusion layer is placed between the membrane electrode frame and the anode flow field groove, wherein the first gas diffusion layer is bonded to the membrane electrode frame. A second gas diffusion layer is placed between the cathode catalyst layer and the cathode flow field groove, wherein the second gas diffusion layer is bonded to the cathode catalyst layer. The adhesive uses one or more of polystyrene, polyether, polyether polyol and epoxy resin. The preferred adhesive is a dual polyurethane material whose main agent is polyester / polyether polyol.

[0057] The cathode catalyst layer is applied using an intermittent coating method, while the anode catalyst layer is applied using a direct coating method. The catalyst coating membrane (CCM) is applied to the adhesive surface of a single-layer frame, which is then applied directly to the anode flow channel surface of the bipolar plate. The anode and cathode flow channel surfaces of the bipolar plate are slotted for carbon paper. The slot depth is the thickness of the pressed carbon paper. One piece of carbon paper is sandwiched between the adhesive surface of the frame and the flow channel, while another piece of carbon paper is placed directly on the non-adhesive side of the frame or bonded to the frame using carbon paper adhesive.

[0058] More specifically, the perfluorosulfonic acid proton exchange membrane has a thickness of 8-12 μm, the membrane electrode frame material is a single-layer polyamide or polyester frame material with a thickness of 20-40 μm, and the cathode catalyst layer is intermittently coated with a platinum loading of 0.3-0.4 mg / cm 2 The anode catalyst layer is directly coated continuously, with a platinum loading of 0.06-0.1 mg / cm 2 The drying temperature of the catalytic layer is 60-100°C and the drying time is 2-8 minutes.

[0059] The modified carbon paper has a thickness of 180-250 μm and a compression of 20-35%. The depth of the anode channel groove of the integrated air-cooled bipolar plate, i.e., the depth of the second groove, is 110-150 μm, and the depth of the cathode channel groove, i.e., the depth of the first groove, is 120-160 μm.

[0060] The present invention will be further described below with reference to specific embodiments.

[0061] Example 1

[0062] A method for preparing a single-frame integrated air-cooled hydrogen fuel cell comprises the following steps:

[0063] (1) Catalytic layer coating process;

[0064] The catalyst slurry was stirred evenly and then degassed by vacuum degassing machine. The platinum loading of the cathode catalyst layer was preset to 0.4 mg / cm 2The platinum loading of the anode catalyst layer is preset to 0.1 mg / cm 2 The cathode catalyst layer was first intermittently coated, with the catalyst slurry evenly applied to the proton exchange membrane to a thickness of 10 μm. After drying at 75°C for 5 minutes, a second direct coating was performed with a coating thickness of 5 μm and drying at 90°C for 5 minutes. The anode catalyst layer was then intermittently coated once, with the treated catalyst slurry evenly applied to the proton exchange membrane surface to a coating thickness of 5 μm. The coating was then dried at 90°C for 5 minutes.

[0065] (2) Single cell assembly;

[0066] Align the anode catalyst layer with the central rectangular area of ​​the membrane electrode frame, and use adhesive to directly bond the membrane electrode frame to the proton exchange membrane. Bond the first gas diffusion layer to the anode catalyst layer using adhesive. Apply adhesive to the edge of the second gas diffusion layer so that it covers the cathode catalyst layer and bond it to the proton exchange membrane. The groove depth of the second groove at the anode flow channel of the integrated air-cooled bipolar plate is 120μm, and the groove depth of the first groove at the cathode flow channel is 120μm. Align the anode of the CCM membrane electrode with the anode flow channel of the integrated air-cooled bipolar plate with grooves on both sides, and align the cathode of the CCM membrane electrode with the cathode flow channel of another integrated air-cooled bipolar plate with grooves on both sides. Clamp the bipolar plates at both ends to press the gas diffusion layer.

[0067] Example 2

[0068] A method for preparing a single-frame integrated air-cooled hydrogen fuel cell comprises the following steps:

[0069] (1) Catalytic layer coating process;

[0070] The catalyst slurry was stirred evenly and then degassed by vacuum degassing machine. The platinum loading of the cathode catalyst layer was preset to 0.3 mg / cm 2 The platinum loading of the anode catalyst layer is preset to 0.075 mg / cm 2 The cathode catalyst layer was first intermittently coated, with the catalyst slurry evenly applied to the proton exchange membrane to a thickness of 7.5 μm. After drying at 75°C for 4 minutes, a second direct coating was performed with a coating thickness of 4 μm and drying at 90°C for 4 minutes. The anode catalyst layer was then evenly coated with the treated catalyst slurry once intermittently, with a coating thickness of 4 μm, and dried at 90°C for 4 minutes.

[0071] (2) Single cell assembly;

[0072] Align the anode catalyst layer with the central rectangular area of ​​the membrane electrode frame, and use adhesive to directly bond the membrane electrode frame to the proton exchange membrane on the anode side. Bond the first gas diffusion layer to the anode catalyst layer using adhesive. Apply adhesive to the edge of the second gas diffusion layer so that it covers the cathode catalyst layer and bonds it to the proton exchange membrane. The groove depth of the second groove at the anode flow channel of the integrated air-cooled bipolar plate is 150μm, and the groove depth of the first groove at the cathode flow channel is 150μm. Align the anode of the CCM membrane electrode with the anode flow channel of the integrated air-cooled bipolar plate with grooves on both sides, and align the cathode of the CCM membrane electrode with the cathode flow channel of the integrated air-cooled bipolar plate with grooves on both sides. Clamp the bipolar plates at both ends to press the gas diffusion layer.

[0073] Example 3

[0074] A method for preparing a single-frame integrated air-cooled hydrogen fuel cell comprises the following steps:

[0075] (1) Catalytic layer coating process;

[0076] The catalyst slurry was stirred evenly and then degassed by vacuum degassing machine. The platinum loading of the cathode catalyst layer was preset to 0.4 mg / cm 2 The platinum loading of the anode catalyst layer is preset to 0.1 mg / cm 2 The cathode catalyst layer was first intermittently coated, with the catalyst slurry evenly applied to the proton exchange membrane to a thickness of 10 μm. After drying at 75°C for 5 minutes, a second direct coating was performed with a coating thickness of 5 μm and drying at 90°C for 5 minutes. The anode catalyst layer was then intermittently coated once, with the treated catalyst slurry evenly applied to the proton exchange membrane surface to a coating thickness of 5 μm. The coating was then dried at 90°C for 5 minutes.

[0077] (2) Single cell assembly;

[0078] Align the anode catalyst layer with the central rectangular area of ​​the membrane electrode frame, and use adhesive to directly bond the membrane electrode frame to the proton exchange membrane of the anode. Bond the first gas diffusion layer to the anode catalyst layer using adhesive. Apply adhesive to the edge of the second gas diffusion layer so that it covers the cathode catalyst layer and bonds it to the proton exchange membrane. The groove depth of the second groove at the anode flow channel of the integrated air-cooled bipolar plate is 120μm, and the groove depth of the first groove at the cathode flow channel is 150μm. Align the anode of the CCM membrane electrode with the anode flow channel of the integrated air-cooled bipolar plate with grooves on both sides, and align the cathode of the CCM with the cathode flow channel of the integrated air-cooled bipolar plate with grooves on both sides. Clamp the bipolar plates at both ends to press the gas diffusion layer.

[0079] Comparative Example 1

[0080] (1) Catalytic layer coating process;

[0081] The catalyst slurry was stirred evenly and then degassed by vacuum degassing machine. The platinum loading of the cathode catalyst layer was preset to 0.4 mg / cm 2 The platinum loading of the anode catalyst layer is preset to 0.1 mg / cm 2 The cathode catalyst layer was first directly coated once, with the catalyst slurry evenly applied to the proton exchange membrane to a thickness of 5 μm. After drying at 75°C for 5 minutes, a second direct coating was performed, with a coating thickness of 5 μm, and drying at 90°C for 5 minutes. The anode catalyst layer was directly coated once, with the treated catalyst slurry evenly applied to the proton exchange membrane surface to a thickness of 5 μm, and dried at 90°C for 5 minutes.

[0082] (2) Single cell assembly;

[0083] The bipolar plates and membrane electrode frames adopt the existing structure, and the thickness of the membrane electrode frame is 120μm. The cathode and anode catalyst layers of the CCM membrane electrode are aligned with the cathode and anode flow fields of the bipolar plates on both sides, and the bipolar plates on both sides are clamped to press the gas diffusion layer.

[0084] Performance testing:

[0085] The polarization curves of the membrane electrodes prepared in Example 1, Example 2, Example 3 and Comparative Example 1 were tested under rated operating conditions (battery temperature was room temperature 25°C; anode / cathode was not humidified; anode H2 pressure was 0.6 bar); respectively. Figure 4 The results show that the polarization curve of the single cell obtained in Example 2 shows the best performance. 2 The voltage at the rated current density is significantly higher than that of Comparative Example 1. This shows that the integrated air-cooled reactor single-frame film electrode of the present invention has better performance.

[0086] Polarization curves of a stack assembled from 60 membrane electrodes prepared in Example 1, Example 2, Example 3 and Comparative Example 1 were tested under rated operating conditions (battery temperature was room temperature 25°C; anode / cathode was not humidified; anode H2 pressure was 0.6 bar). Figure 5 The results show that the polarization curve of Example 2 exhibits the best performance, and the voltage and power at the rated current of 100 A are significantly higher than those of Comparative Example 1. This indicates that the integrated air-cooled reactor single-frame film electrode of the present invention has better performance.

[0087] Parts not described in the above methods can be achieved by adopting or drawing on existing technologies.

[0088] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements to the technical solutions of the present invention made by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. An air-cooled hydrogen fuel cell bipolar plate, characterized in that: It includes a plate body, a first groove is provided on one side of the plate body, a cathode flow channel is arranged in the first groove, a second groove is provided on the other side of the plate body, an anode flow channel is arranged in the second groove, and an air inlet and an air outlet are respectively provided at both ends of the plate body, and the air inlet and the air outlet are respectively connected to the two ends of the anode flow channel.

2. The air-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that: The cathode flow channel adopts a parallel flow channel; the anode flow channel adopts a serpentine flow channel.

3. The air-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that: The plate body is rectangular, and the arrangement direction of the parallel flow channels is perpendicular to the extension direction of the plate body; the main flow direction of the serpentine flow channels is consistent with the extension direction of the plate body.

4. The air-cooled hydrogen fuel cell bipolar plate according to claim 3, characterized in that: The serpentine flow channels are arranged in a plurality of groups, and the main body of each group of serpentine flow channels occupies a certain area of ​​the second groove.

5. The air-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that: A sealing groove is provided around the circumference of the second groove.

6. The air-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that: The groove depth of the first groove is 110-170 μm, and the groove depth of the second groove is 100-160 μm; the height of the cathode flow channel is smaller than the groove depth of the first groove, and the height of the anode flow channel is smaller than the groove depth of the second groove.

7. A single battery, characterized in that: A bipolar plate according to any one of claims 1 to 6 is used, specifically further comprising a CCM membrane electrode, a membrane electrode frame, a first gas diffusion layer and a second gas diffusion layer, wherein a rectangular opening adapted to the CCM membrane electrode is provided at the center of the membrane electrode frame; the CCM membrane electrode is fixed to the membrane electrode frame, the first gas diffusion layer is bonded to one side of the CCM membrane electrode, and the second gas diffusion layer is bonded to the other side of the CCM membrane electrode; one of the bipolar plates is provided on one side of the membrane electrode frame, and after lamination, the first gas diffusion layer is located in the first groove of the bipolar plate, and the other bipolar plate is provided on the other side of the membrane electrode frame, and after lamination, the second gas diffusion layer is located in the second groove of the bipolar plate.

8. The single battery according to claim 7, characterized in that: The first gas diffusion layer and the second gas diffusion layer are both made of carbon paper with a thickness of 150-260 μm and a compression amount of 15-40%.

9. A fuel cell stack, characterized in that: A plurality of single cells as claimed in claim 7 are stacked and arranged, with upper and lower adjacent single cells sharing a bipolar plate.

10. The method for preparing a fuel cell stack according to claim 9, characterized in that The following steps are involved: (1) Coating a cathode catalyst layer and an anode catalyst layer on both sides of a proton exchange membrane to obtain a CCM membrane electrode; (2) overlapping the anode catalyst layer of the CCM membrane electrode with the rectangular opening area in the center of the membrane electrode frame, and directly bonding the membrane electrode frame to the proton exchange membrane of the CCM membrane electrode; (3) The bipolar plates are formed by integrated stamping, and after etching and grooving, the cathode and anode channels are machined by CNC cutting; (4) placing a first gas diffusion layer between the membrane electrode frame and the second groove of one of the bipolar plates, and bonding the first gas diffusion layer to the membrane electrode frame; placing a second gas diffusion layer between the CCM membrane electrode and the first groove of the other bipolar plate, and bonding the second gas diffusion layer to the CCM membrane electrode; (5) Pressing the two bipolar plates together with the first gas diffusion layer, the membrane electrode frame, the CCM membrane electrode, and the second gas diffusion layer therebetween to form a single cell; (6) Several single cells are stacked up and down, and the upper and lower adjacent single cells share a bipolar plate to form an air-cooled hydrogen fuel cell stack.

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