Fuel cell stack and in-situ performance detection and performance recovery method for inner membrane electrode of fuel cell stack

Abstract

The invention discloses a fuel cell stack and an inner membrane electrode in-situ performance detection and performance recovery method thereof. The fuel cell stack comprises a plurality of inner membrane electrodes stacked in series and bipolar plates arranged between the adjacent inner membrane electrodes, the cathode side and the anode side of each bipolar plate are respectively provided with a cathode tab and an anode tab, and the cathode tab and the anode tab extend outwards from the edge of the corresponding bipolar plate along the direction parallel to the plane of the bipolar plate; the tab structure is arranged on the bipolar plate of the electric pile, so that independent maintenance and performance recovery of a fault membrane electrode are effectively realized, the overall service life of the electric pile is guaranteed, and secondary damage to the membrane electrode is avoided.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane fuel cell technology, and in particular to a method for in-situ performance testing and performance recovery of a fuel cell stack and its inner membrane electrode. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) offer advantages such as high energy conversion efficiency, zero pollution, low noise, and environmental friendliness, and have made significant progress in various applications including road transportation, marine engineering, and backup power plants. In recent years, PEMFCs have also been widely used in the low-altitude hydrogen economy.

[0003] Despite the rapid development of fuel cell technology, its lifespan still has significant room for improvement compared to traditional diesel and gasoline engines. The main reasons for its insufficient lifespan are as follows: The catalyst on the cathode side of the fuel cell membrane electrode assembly (MEA) remains at a high potential for extended periods, leading to Pt particle agglomeration, dissolution, and loss, resulting in decreased power generation performance and lifespan. Rapid load changes and start-stop cycles under complex road conditions, along with temperature fluctuations and the formation of hydrogen-air interfaces, also cause oxidation of the Pt catalyst surface. The Pt catalyst is highly sensitive to impurity gases and ions; even trace amounts of impurities in the anode hydrogen or cathode air adsorbed onto the Pt particle surface can significantly reduce fuel cell power generation performance (the carbon monoxide content in the hydrogen must be below 10 ppm, otherwise it will severely impact power generation performance). Control strategy failure or insufficient gas supply to the anode and cathode can also cause performance degradation in one or more MEAs within the fuel cell stack. In order to restore the performance of membrane electrodes that have degraded, the current in the prior art cannot flow through a single inner membrane electrode, but can only flow through all the inner membrane electrodes of a stack. The electrochemical performance testing or performance restoration process relies on the electrochemical workstation to generate current for a single inner membrane electrode. Therefore, the stack cannot test or restore the performance of a single inner membrane electrode, which is time-consuming, labor-intensive, and prone to causing secondary damage to the membrane electrodes.

[0004] Therefore, there is a need to provide a solution for independent performance testing and recovery of the inner membrane electrode to improve the efficiency of performance testing and recovery while reducing secondary damage to the membrane electrode. Summary of the Invention

[0005] In view of this, this application provides a method for in-situ performance testing and recovery of fuel cell stacks and their inner membrane electrodes, which solves the problem of how to improve the method of inner membrane electrode performance testing and recovery without causing secondary damage.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a fuel cell stack, including a plurality of inner membrane electrodes stacked in series and bipolar plates disposed between adjacent inner membrane electrodes; each bipolar plate has a cathode tab and an anode tab on its cathode side and an anode side, respectively, and the cathode tab and the anode tab extend outward from the edge of the corresponding bipolar plate in a direction parallel to the plane of the bipolar plate.

[0007] Preferably, the cathode tab and anode tab are integrally formed with the corresponding bipolar plate.

[0008] Secondly, this application provides a method for in-situ performance testing and performance recovery of the inner membrane electrode based on a fuel cell stack, comprising the following steps: S1. Identify the target inner membrane electrode; S2. Connect the electrodes of the electrochemical workstation to the cathode and anode tabs of the bipolar plate corresponding to the target inner membrane electrode; input nitrogen gas into the cathode and hydrogen gas into the anode of the fuel cell stack, and maintain the gas supply until the open circuit voltage of the target inner membrane electrode is lower than the target value. S3. Use cyclic voltammetry or hydrogen pump activation method to test and / or restore the performance of the target inner membrane electrode.

[0009] Preferably, the target inner membrane electrode in step S1 is any designated inner membrane electrode or abnormal inner membrane electrode in the fuel cell stack.

[0010] Preferably, the method for determining abnormal inner membrane electrodes is as follows: Connect voltage monitoring lines to the cathode tabs and anode tabs of the corresponding bipolar plates of each individual inner membrane electrode, input air to the cathode and hydrogen to the anode, monitor the output voltage of each individual inner membrane electrode in real time when the fuel cell stack is working, and mark the inner membrane electrode whose output voltage is lower than the limit value, which is the abnormal inner membrane electrode.

[0011] Preferably, in step S2, both nitrogen and hydrogen are saturated humid gases at the corresponding fuel cell stack temperature; and both nitrogen and hydrogen are input at atmospheric pressure.

[0012] Preferably, the limit value is 70% of the average output voltage of the fuel cell stack.

[0013] Preferably, the target value is 0.1V.

[0014] Preferably, in step S3, the working electrode of the electrochemical workstation is connected to the cathode tab of the bipolar plate corresponding to the target inner membrane electrode, and the counter electrode and the reference electrode are both connected to the anode tab of the bipolar plate corresponding to the target inner membrane electrode.

[0015] Preferably, when the number of abnormal inner membrane electrodes is greater than 1, they are processed sequentially according to the marking. After the in-situ performance of a single abnormal inner membrane electrode is restored or tested, the in-situ performance of the next abnormal inner membrane electrode is restored or tested.

[0016] Preferably, the current range of the electrochemical workstation is such that a current of not less than 100 mA / cm² passes through the unit active area of ​​the inner membrane electrode.

[0017] The beneficial effects of this application are as follows: By setting a tab structure on the bipolar plates of the fuel cell stack, when one or more membrane electrodes fail, the workstation electrode clamp can be directly clamped onto the tabs of the bipolar plates on both sides of the faulty membrane electrode without disassembling the fuel cell stack. This directly constructs an independent current loop flowing through the membrane electrode for performance testing or recovery operations. This method precisely isolates the target unit, preventing current from flowing through other normal membrane electrodes, completely eliminating the risk of secondary damage to non-faulty membrane electrodes during maintenance. At the same time, it significantly simplifies the operation process, eliminates the high cost and potential damage caused by overall disassembly, effectively achieves independent maintenance and performance recovery of the faulty membrane electrode, and ensures the overall lifespan of the fuel cell stack. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the bipolar plate structure of this application; Figure 2 This is a schematic diagram of the structure of the fuel cell stack of this application.

[0019] In the diagram: 1. Bipolar plate; 11. Cathode tab; 12. Anode tab; 2. Inner membrane electrode. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] like Figure 2 As shown, this application provides a fuel cell stack, including multiple inner membrane electrodes 2 stacked in series and bipolar plates 1 disposed between adjacent inner membrane electrodes 2; each bipolar plate 1 has a cathode tab 11 and an anode tab 12 on its cathode side and anode side, respectively, and the cathode tab 11 and anode tab 12 extend outward from the edge of the corresponding bipolar plate 1 in a direction parallel to the plane of the bipolar plate 1. The key point of this invention is that any membrane electrode and the bipolar plates 1 on both sides can be regarded as a small unit. After the current comes out from the electrochemical workstation, it enters the bipolar plate 1 through the tab on one side of the membrane electrode, then enters the membrane electrode, and then comes out from the other side of the membrane electrode into the other side of the bipolar plate 1, and then returns to the workstation through the tab of that bipolar plate 1. The bipolar plates of this application are welded together by adjacent cathode plates and anode plates. For example, bipolar plate No. 1 is welded together by welding the cathode plate of inner membrane electrode No. 1 and the anode plate of inner membrane electrode No. 2.

[0022] Compared to existing technologies, such as Figure 1As shown, the bipolar plate of this application has a cathode tab 11 and an anode tab 12. Existing fuel cell stacks have a tabless-free bipolar plate 1 structure, meaning current cannot flow through a single inner membrane electrode 2 independently; it can only flow through all the inner membrane electrodes 2 of the stack. Since electrochemical performance testing or recovery relies on an electrochemical workstation generating current on a single inner membrane electrode 2, the tabless-free bipolar plate stack cannot perform performance testing or recovery on any single inner membrane electrode 2. However, the fuel cell stack of this application allows for independent in-situ characterization and performance recovery of the electrochemical parameters of any inner membrane electrode 2, without requiring multiple disassembly and reassembly of the stack.

[0023] In some embodiments, the cathode tab 11 and the anode tab 12 are integrally formed with the corresponding bipolar plate 1.

[0024] This application provides a method for in-situ performance testing and performance recovery of the inner membrane electrode 2 based on a fuel cell stack, including the following steps: S1. Determine the target inner membrane electrode 2; S2. Connect the electrodes of the electrochemical workstation to the cathode tab 11 and anode tab 12 of the bipolar plate 1 corresponding to the target inner membrane electrode 2; input nitrogen gas into the cathode and hydrogen gas into the anode of the fuel cell stack, and maintain the gas supply until the open circuit voltage of the target inner membrane electrode 2 is lower than the target value. S3. Use cyclic voltammetry or hydrogen pump activation method to test and / or restore the performance of the target inner membrane electrode 2.

[0025] The inventors discovered that in an electrode stack containing multiple inner membrane electrodes 2 (e.g., 300 inner membrane electrodes 2 connected in series), if one or more inner membrane electrodes 2 experience performance degradation or malfunction, the electrode stack must be disassembled to remove the faulty inner membrane electrode 2 for performance testing and restoration. This method has several drawbacks: 1. Time-consuming and labor-intensive: Even excluding testing time, manual assembly of 300 inner membrane electrodes 2 requires at least 2-3 days; 2. Prone to damage to the inner membrane electrodes 2: As inner membrane electrodes 2 are disposable, repeated disassembly and reassembly inevitably cause damage due to difficulty in controlling alignment accuracy and pressure damage.

[0026] In this application, after the bipolar plate 1 of the fuel cell stack is equipped with a tab structure, when one or more inner membrane electrodes 2 inside the fuel cell stack fail, it is not necessary to remove the inner membrane electrode 2 from the fuel cell stack. Instead, the electrode clip of the workstation is placed on the tabs of the bipolar plate 1 on both sides of the inner membrane electrode 2. At this time, the current can flow through the inner membrane electrode 2 alone without flowing through all the inner membrane electrodes 2. In this way, the performance of the faulty inner membrane electrode 2 can be tested or restored, and the performance of the degraded inner membrane electrode 2 can be restored independently. At the same time, this process will not cause secondary damage to any inner membrane electrode 2.

[0027] In some embodiments, the target inner membrane electrode 2 in step S1 is any designated inner membrane electrode 2 or an abnormal inner membrane electrode 2 in the fuel cell stack.

[0028] In this embodiment, when only performance testing of the inner membrane electrode 2 is required, the target inner membrane electrode 2 can be defined as any designated inner membrane electrode 2 in the fuel cell stack, and any designated inner membrane electrode 2 can complete the performance testing. When performance repair of a damaged inner membrane electrode 2 is required, the target inner membrane electrode 2 is defined as an abnormal inner membrane electrode 2, and the abnormal inner membrane electrode 2 can complete performance repair and performance testing before and after repair. The test characterization items include electrochemical parameter testing of the electrochemical active area, hydrogen permeation current density, and AC impedance of any inner membrane electrode 2 in the fuel cell stack, as well as in-situ characterization of the electrochemical parameters of an inner membrane electrode 2 whose performance has degraded before and after performance recovery.

[0029] In some embodiments, the abnormal inner membrane electrode 2 is determined as follows: a voltage monitoring line is connected to the cathode tab 11 and anode tab 12 of the corresponding bipolar plate of each individual inner membrane electrode 2. Air is input to the cathode and hydrogen is input to the anode. The output voltage of each individual inner membrane electrode 2 is monitored in real time when the fuel cell stack is working. The inner membrane electrode 2 with an output voltage lower than the limit value is marked as the abnormal inner membrane electrode 2.

[0030] Specifically, the method for in-situ performance testing and performance recovery of the inner membrane electrode 2 based on the fuel cell stack is as follows: S1 First, the fuel cell stack is assembled on the fuel cell test bench. During the operation of the fuel cell stack, the working voltage of each inner membrane electrode 2 is monitored by voltage inspection. The anode and cathode electrodes of the voltage inspection line are connected to the cathode tab 11 and anode tab 12 of the corresponding bipolar plate 1 of the inner membrane electrode 2. The output voltage value of each inner membrane electrode 2 during the operation of the fuel cell stack is monitored by the voltage inspection line connected to each bipolar plate 1. One or more inner membrane electrodes 2 with significantly low output voltage values ​​are marked. S2. Switch the cathode gas of the fuel cell stack from air, which is normally input, to nitrogen, and the anode gas to hydrogen, with the nitrogen flow rate being the same as the hydrogen flow rate, both being 10 mL / min / cm² / plate; connect the electrode of the electrochemical workstation to the tab of the anode and cathode bipolar plate 1 corresponding to the inner membrane electrode 2 marked with low output voltage, and use electrochemical methods such as cyclic voltammetry or hydrogen pump activation to restore the performance of the inner membrane electrode 2.

[0031] In some embodiments, in step S2, both nitrogen and hydrogen are saturated humid gases at the corresponding stack temperature; and both nitrogen and hydrogen are input at atmospheric pressure.

[0032] In some embodiments, the limit is 70% of the average output voltage of the fuel cell stack.

[0033] In some embodiments, the target value is 0.1V.

[0034] In some embodiments, in step S3, the working electrode of the electrochemical workstation is connected to the cathode tab 11 of the bipolar plate 1 corresponding to the target inner membrane electrode 2, and the counter electrode and the reference electrode are both connected to the anode tab 12 of the bipolar plate 1 corresponding to the target inner membrane electrode 2.

[0035] In this embodiment, the voltage applied to the inner membrane electrode 2 by the electrochemical workstation is applied to the inner membrane electrode 2 through the tab of the bipolar plate 1, and at the same time, the current generated by the inner membrane electrode 2 is fed back to the electrochemical workstation through the tab of the bipolar plate 1.

[0036] In some embodiments, the current range of the electrochemical workstation is such that a current of not less than 100 mA / cm² passes through a unit active area of ​​the inner membrane electrode 2.

[0037] In some embodiments, when the number of abnormal inner membrane electrodes 2 is greater than 1, they are processed sequentially according to the marking. After the in-situ performance of a single abnormal inner membrane electrode 2 is restored or tested, the in-situ performance of the next abnormal inner membrane electrode 2 is restored or tested, that is, steps S2 and S3 are repeated.

[0038] In some embodiments, a system for in-situ performance testing and performance recovery of the inner membrane electrode 2 of a fuel cell stack includes a fuel cell stack with tabs, a multi-channel voltage monitoring device, a gas switching control system, an electrochemical workstation, and a parameter feedback adjustment module.

[0039] The following specific embodiments further illustrate this solution.

[0040] Example 1 A fuel cell stack includes multiple inner membrane electrodes 2 stacked in series and bipolar plates 1 disposed between adjacent inner membrane electrodes 2; each bipolar plate 1 has a cathode tab 11 and an anode tab 12 on its cathode side and anode side, respectively, the cathode tab 11 and the anode tab 12 extending outward from the edge of the corresponding bipolar plate 1 in a direction parallel to the plane of the bipolar plate 1, and the cathode tab 11 and the anode tab 12 are integrally formed with the corresponding bipolar plate 1.

[0041] A method for in-situ performance recovery of inner membrane electrode 2 based on fuel cell stack includes the following steps: S1. The fuel cell stack is assembled on the fuel cell test bench. During the operation of the fuel cell stack, the working voltage of the inner membrane electrode 2 is monitored by voltage inspection in sequence. The anode and cathode electrodes of the voltage inspection line are connected to the cathode tab 11 and anode tab 12 of the bipolar plate 1 corresponding to the inner membrane electrode 2. Air is input to the cathode and hydrogen is input to the anode. The output voltage value of each inner membrane electrode 2 during the operation of the fuel cell stack is monitored in real time through the voltage inspection line connected to each bipolar plate 1. The inner membrane electrode 2 whose output voltage value is significantly lower than 70% of the average output voltage of the stack is marked as abnormal inner membrane electrode 2. The abnormal inner membrane electrodes 2 numbered 4 / 24 / 49 / 61 / 83 are used as target inner membrane electrodes 2. S2. Connect the working electrode of the electrochemical workstation to the cathode tab 11 of the bipolar plate 1 of the inner membrane electrode 2 (No. 4), and connect the reference electrode and the counter electrode to the anode tab 12 of the bipolar plate 1 of the inner membrane electrode 2 (No. 4); saturated wet hydrogen is introduced into the anode chamber of the fuel cell stack, and saturated wet nitrogen is introduced into the cathode chamber. The flow rates of hydrogen and nitrogen are the same and set to the minimum flow rate when the fuel cell stack is working normally, both set to 10 mL / min / cm² / plate, until the open circuit voltage of all inner membrane electrodes 2 in the fuel cell stack drops below 0.1 V; S3. Turn on the cyclic voltammetry mode of the electrochemical workstation, set the start potential and end potential to the open circuit voltage of inner membrane electrode 2 (No. 4), set the upper limit of the working potential to 1.25 V, and set the lower limit of the working potential to the open circuit potential minus 0.05 V. After the above steps are completed, start the in-situ performance restoration of inner membrane electrode 2, set the voltage scan rate to 100 mV / s, and the number of scans to 50, until the current curves during the potential scan process overlap, thus completing the repair of inner membrane electrode 2 (No. 4). Repeat step S2 to repair abnormal inner membrane electrodes 2 (Nos. 24 / 49 / 61 / 83).

[0042] Example 2 A fuel cell stack, identical to that in Example 1.

[0043] A method for in-situ performance recovery of inner membrane electrode 2 based on fuel cell stack is the same as in Example 1, except that in step S3, the current density is gradually increased from 0 to 1500 mA / cm² in steps of 100 mA / cm². After reaching the target current density, a chronopotential test is performed for 20 hours to complete the performance recovery of inner membrane electrode 2 (No. 4). Step S2 is repeated to restore the performance of abnormal inner membrane electrodes 2 (Nos. 24, 49, 61, and 83).

[0044] Example 3 A fuel cell stack, identical to that in Example 1.

[0045] A method for in-situ performance testing and performance recovery of inner membrane electrode 2 based on fuel cell stack, which is the same as in Example 1 except that: Step S3. Open the cyclic voltammetry mode of the electrochemical workstation, set the start and end potentials to the open-circuit voltage of membrane electrode 4, the upper limit of the working potential to 1.25 V, and the lower limit of the working potential to the open-circuit potential minus 0.05 V. After completing the above steps, begin the electrochemical active area detection: set the voltage scan rate to 20 mV / s and the number of scans to 20, until the current curves during the potential scan coincide. Measure the electrochemical active area of ​​inner membrane electrode 2 (No. 4) before performance recovery. Repeat steps S2 and S3 in Example 1 to perform in-situ recovery of the performance of inner membrane electrode 2. Then, open the cyclic voltammetry mode of the electrochemical workstation again, set the start and end potentials to the open-circuit voltage of membrane electrode 4, set the upper limit of the working potential to 1.25 V, and the lower limit of the working potential to the open-circuit potential minus 0.05 V. After completing the above steps, begin the electrochemical active area detection: set the voltage scan rate to 20 mV / s and the number of scans to 20. The electrochemical active area of ​​inner membrane electrode 2 after performance recovery was obtained by measuring mV / s and scanning 20 times until the current curves during the potential scanning process overlapped.

[0046] Example 4 A fuel cell stack, identical to that in Example 1.

[0047] A method for in-situ performance testing of inner membrane electrode 2 based on fuel cell stack is the same as in Example 1, except that... S1. Designate any membrane electrode from fuel cell stack number 1 to 100 as the target inner membrane electrode 2; S2. Connect the working electrode of the electrochemical workstation to the cathode tab 11 of the bipolar plate 1 of the target inner membrane electrode 2, and connect the reference electrode and the counter electrode to the anode tab 12 of the bipolar plate 1 of the target inner membrane electrode 2; saturated wet hydrogen is introduced into the anode chamber of the fuel cell stack, and saturated wet nitrogen is introduced into the cathode chamber. The flow rates of hydrogen and nitrogen are the same and set to the minimum flow rate when the fuel cell stack is working normally, both set to 10 mL / min / cm² / plate, until the open circuit voltage of all inner membrane electrodes 2 in the fuel cell stack drops below 0.1 V; S3. Turn on the cyclic voltammetry mode of the electrochemical workstation, set the start potential and end potential to the open circuit voltage of the target inner membrane electrode 2, set the upper limit of the working potential to 1.25 V, and set the lower limit of the working potential to the open circuit potential minus 0.05 V; after the above steps are completed, start the electrochemical active area detection: set the voltage scan rate to 20 mV / s, set the number of scans to 20, until the current curves during the potential scan process overlap, and the electrochemical active area of ​​the target inner membrane electrode 2 is obtained.

[0048] Example 5 A fuel cell stack, identical to that in Example 4.

[0049] A method for in-situ performance testing of inner membrane electrode 2 based on fuel cell stack is the same as in Example 4, except that... Step S3. Turn on the cyclic voltammetry mode of the electrochemical workstation, set the start potential and end potential to the open circuit voltage of the target inner membrane electrode 2, set the upper limit of the working potential to 0.5 V, and set the lower limit of the working potential to the open circuit potential; after the above steps are completed, start the hydrogen permeation current density detection: set the voltage scan rate to 2 mV / s, set the number of scans to 5, until the current curves during the potential scan process overlap, and obtain the hydrogen permeation current density of the target inner membrane electrode 2.

[0050] Example 6 A fuel cell stack, identical to that in Example 4.

[0051] A method for in-situ performance testing of inner membrane electrode 2 based on fuel cell stack is the same as in Example 4, except that... Step S2. Connect the working electrode of the electrochemical workstation to the cathode tab 11 of the bipolar plate 1 of the target inner membrane electrode 2, and connect the reference electrode and the counter electrode to the anode tab 12 of the bipolar plate 1 of the target inner membrane electrode 2; saturated humid hydrogen is introduced into the anode chamber of the fuel cell stack at a flow rate of 10 mL / min / cm² / plate, while ensuring that the stoichiometry is not less than 1.5; saturated humid air is introduced into the cathode chamber at a flow rate of 25 mL / min / cm² / plate, while ensuring that the stoichiometry is not less than 2.0. S3. Set a working current on the fuel cell test bench to enable the fuel cell stack to generate electricity normally; select the constant current perturbation detection AC impedance mode on the electrochemical workstation, and set a perturbation AC current, the value of which is 10% of the fuel cell discharge current, the initial value of the frequency of the perturbation current is 10000 Hz, and the termination value is 0.1 Hz. After the above steps are completed, start the AC impedance detection of the membrane electrode to be tested, and obtain the AC impedance of the target inner membrane electrode 2.

[0052] This invention, by setting tab structures on the bipolar plates 1 of the fuel cell stack, allows the workstation electrode clamp to be directly clamped onto the tabs of the bipolar plates 1 on both sides of the faulty membrane electrode without disassembling the fuel cell stack when one or more membrane electrodes fail. This directly constructs an independent current loop flowing through the faulty membrane electrode for performance testing or recovery operations. This method precisely isolates the target unit, preventing current from flowing through other normal membrane electrodes, completely eliminating the risk of secondary damage to non-faulty membrane electrodes during maintenance. At the same time, it significantly simplifies the operation process, eliminates the high cost and potential damage caused by overall disassembly, effectively achieves independent maintenance and performance recovery of the faulty membrane electrode, and ensures the overall lifespan of the fuel cell stack.

[0053] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A fuel cell stack, characterized in that, It includes multiple inner membrane electrodes (2) stacked in series and bipolar plates (1) disposed between adjacent inner membrane electrodes (2); each bipolar plate (1) is provided with a cathode tab (11) and an anode tab (12) on the cathode side and the anode side, respectively, and the cathode tab (11) and the anode tab (12) extend outward from the edge of the corresponding bipolar plate (1) in a direction parallel to the plane of the bipolar plate (1).

2. The fuel cell stack according to claim 1, characterized in that, The cathode tab (11) and anode tab (12) are integrally formed with the corresponding bipolar plate (1).

3. A method for in-situ performance testing and performance recovery of the inner membrane electrode based on a fuel cell stack as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. Determine the target inner membrane electrode (2); S2. Connect the electrodes of the electrochemical workstation to the cathode tab (11) and anode tab (12) of the bipolar plate (1) corresponding to the target inner membrane electrode (2); input nitrogen gas into the cathode of the fuel cell stack and hydrogen gas into the anode, and maintain the gas supply until the open circuit voltage of the target inner membrane electrode (2) is lower than the target value. S3. The performance of the target inner membrane electrode (2) is tested and / or restored by cyclic voltammetry or hydrogen pump activation method.

4. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 3, characterized in that, The target inner membrane electrode (2) in step S1 is any designated inner membrane electrode (2) or abnormal inner membrane electrode (2) in the fuel cell stack.

5. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 4, characterized in that, The method for determining the abnormal inner membrane electrode (2) is as follows: Connect voltage monitoring lines to the cathode tab (11) and anode tab (12) of the corresponding bipolar plates of each single inner membrane electrode (2), input air to the cathode and hydrogen to the anode, monitor the output voltage of each single inner membrane electrode (2) in real time when the fuel cell stack is working, and mark the inner membrane electrode (2) whose output voltage is lower than the limit value, which is the abnormal inner membrane electrode (2).

6. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 3, characterized in that, In step S2, both nitrogen and hydrogen are saturated humid gases at the corresponding fuel cell stack temperature; and both nitrogen and hydrogen are input at atmospheric pressure.

7. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 5, characterized in that, The limit value is 70% of the average output voltage of the fuel cell stack.

8. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 3, characterized in that, The target value is 0.1V.

9. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 3, characterized in that, In step S3, the working electrode of the electrochemical workstation is connected to the cathode tab (11) of the bipolar plate (1) corresponding to the target inner membrane electrode (2), and the counter electrode and the reference electrode are both connected to the anode tab (12) of the bipolar plate (1) corresponding to the target inner membrane electrode (2).

10. The method for in-situ performance testing and performance recovery of the inner membrane electrode of a fuel cell stack according to claim 4, characterized in that, When the number of abnormal inner membrane electrodes (2) is greater than 1, they are processed in sequence according to the marking. After the in-situ performance of a single abnormal inner membrane electrode (2) is restored or tested, the in-situ performance of the next abnormal inner membrane electrode (2) is restored or tested.

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