Airtightness detection device compatible with air-cooled stack membrane electrode and bipolar plate

Abstract

The utility model discloses an air-tightness detection device compatible with an air-cooled stack membrane electrode and a bipolar plate. The air-tightness detection device comprises an air storage tank, a pressure reduction unit, first to fourth air inlet valves, first to third exhaust valves and a flow meter, the gas storage tank is communicated with a first gas inlet valve and a second gas inlet valve through a pressure reduction unit, the first gas inlet valve is communicated with a cathode end of a membrane electrode, the second gas inlet valve is communicated with a third gas inlet valve and a fourth gas inlet valve, an anode end of the membrane electrode is communicated with a shared gas port of the bipolar plate, and the third gas inlet valve and the fourth gas inlet valve are communicated with the shared gas port; the first exhaust valve is arranged on a pipeline between the first air inlet valve and the cathode end, the second exhaust valve is arranged on a pipeline between the third air inlet valve and the shared air port, the flow meter is arranged on a pipeline between the second air inlet valve and the shared air port, and the third exhaust valve is arranged on a pipeline between the flow meter and the shared air port. According to the utility model, airtight detection of the membrane electrode and the bipolar plate can be realized.

Description

Technical Field

[0001] This utility model belongs to the field of fuel cell air tightness testing technology, and in particular relates to an air tightness testing device compatible with air-cooled fuel cell stack membrane electrode and bipolar plate. Background Technology

[0002] The fuel cell stack is the core of a fuel cell's functionality, comprising components such as a proton exchange membrane, catalyst, gas diffusion layer, bipolar plates, current collectors, sealing components, and end plates. The stack is where electrochemical reactions occur. Because the output power of a single fuel cell unit is relatively small, multiple fuel cell units are typically stacked in series to form a stack to increase the overall output power. The stack consists of alternating layers of bipolar plates (BP) and membrane electrode assemblies (MEAs), with seals embedded between each unit. After being pressed together by front and rear end plates, they are secured with screws. The MEA, composed of a proton exchange membrane, catalyst layer, and gas diffusion layer, is a key component for fuel cell power generation and also the site of multiphase mass transport and electrochemical reactions, determining the fuel cell's performance, lifespan, and cost. The bipolar plates conduct electrons, distribute reactant gases, and remove generated water. Functionally, the bipolar plate material must be a good conductor of electricity and heat, possess sufficient strength, and have gas tightness.

[0003] As fuel cell production scales up, the demand for airtightness testing is also increasing. Currently, airtightness testing of membrane electrode assemblies (MEAs) and bipolar plates requires separate devices, resulting in complex testing circuits, high costs, and low testing efficiency. Utility Model Content

[0004] The purpose of this invention is to provide an airtightness testing device compatible with both the membrane electrode and bipolar plate of an air-cooled fuel cell stack, in order to solve the problem that existing air-cooled fuel cell stacks require separate testing devices for the membrane electrode and bipolar plate to test their airtightness performance, resulting in complex testing circuits, high costs, and low testing efficiency.

[0005] This utility model solves the above-mentioned technical problems through the following technical solution: an airtightness detection device compatible with air-cooled electric stack membrane electrode and bipolar plate, including an air storage tank, a pressure reducing unit, a first air inlet valve, a second air inlet valve, a third air inlet valve, a fourth air inlet valve, a first exhaust valve, a second exhaust valve, a third exhaust valve and a flow meter.

[0006] The gas storage tank is connected to the first and second inlet valves through a pressure reducing unit. The first inlet valve is connected to the cathode end of the membrane electrode. The second inlet valve is connected to the third and fourth inlet valves and the common air port of the anode end of the membrane electrode and the bipolar plate. The third inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate. The fourth inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate.

[0007] The first exhaust valve is located on the pipeline between the first intake valve and the cathode end of the membrane electrode; the second exhaust valve is located on the pipeline between the third intake valve and the anode end of the membrane electrode and the common air port of the bipolar plate; the flow meter is located on the pipeline between the second intake valve and the anode end of the membrane electrode and the common air port of the bipolar plate; and the third exhaust valve is located on the pipeline between the flow meter and the anode end of the membrane electrode and the common air port of the bipolar plate.

[0008] Furthermore, the pressure reducing unit includes a first pressure reducing valve and a second pressure reducing valve connected in sequence.

[0009] Furthermore, a first pressure transmitter is also provided on the pipeline between the pressure reducing unit and the second intake valve.

[0010] Furthermore, a second pressure transmitter is provided in the pipeline between the flow meter and the anode of the membrane electrode and the common air port of the bipolar plate.

[0011] Furthermore, the airtightness detection device also includes a control module, and the first intake valve, the second intake valve, the third intake valve, the fourth intake valve, the first exhaust valve, the second exhaust valve, and the third exhaust valve are respectively connected to the control module.

[0012] Furthermore, a safety valve is provided on the gas storage tank.

[0013] Furthermore, a filter is provided on the pipeline between the gas storage tank and the pressure reducing unit.

[0014] Furthermore, the gas storage tank is also connected to an external gas source via a triplet.

[0015] Compared with the prior art, the advantages of this utility model are:

[0016] This invention enables the airtightness testing of the membrane electrode and bipolar plate of an air-cooled fuel cell stack using a single testing device, eliminating the need for two separate testing devices to test the membrane electrode and bipolar plate, thus reducing costs and improving testing efficiency.

[0017] The detection device of this utility model has a simple structure, low environmental requirements, strong anti-interference ability, and small footprint, which solves the problems of traditional detection equipment being heavy, occupying a large area, and inconvenient for maintenance, troubleshooting, and relocation. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the airtightness testing device compatible with air-cooled fuel cell membrane electrode and bipolar plate in an embodiment of this utility model. The dashed line represents the flow pipeline during membrane electrode airtightness testing, and the solid line represents the flow pipeline during bipolar plate airtightness testing. Detailed Implementation

[0020] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] To address the issue that traditional air-cooled fuel cell stacks require separate testing devices for membrane electrode assemblies (MEAs) and bipolar plates for air tightness testing, this invention provides an air tightness testing device compatible with both MEAs and bipolar plates. This device enables air tightness testing of both MEAs and bipolar plates without the need for two separate devices, thus reducing testing costs and improving testing efficiency.

[0022] Figure 1 A schematic diagram of a gas tightness testing device compatible with air-cooled fuel cell stack membrane electrodes and bipolar plates is shown. Figure 1 As shown, the airtightness testing device compatible with air-cooled fuel cell stack membrane electrode and bipolar plate provided by this utility model includes an air tank, a pressure reducing unit, a first air inlet valve, a second air inlet valve, a third air inlet valve, a fourth air inlet valve, a first exhaust valve, a second exhaust valve, a third exhaust valve, and a flow meter; the air tank is connected to the first air inlet valve and the second air inlet valve through the pressure reducing unit; the first air inlet valve is connected to the cathode end of the membrane electrode; the second air inlet valve is connected to the third air inlet valve, the fourth air inlet valve, and the common air port of the anode end of the membrane electrode and the bipolar plate; the third air inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate; and the fourth air inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate. The first exhaust valve is located on the pipeline between the first intake valve and the cathode of the membrane electrode; the second exhaust valve is located on the pipeline between the third intake valve and the anode of the membrane electrode and the common port of the bipolar plate; the flow meter is located on the pipeline between the second intake valve and the anode of the membrane electrode and the common port of the bipolar plate; and the third exhaust valve is located on the pipeline between the flow meter and the anode of the membrane electrode and the common port of the bipolar plate.

[0023] The airtightness test of the membrane electrode assembly (MEA) is essentially a test of its gas permeability. During the test, the first vent valve, second vent valve, second inlet valve, and fourth inlet valve are closed. Gas in the storage tank is depressurized by a pressure reducing unit before entering the cathode of the MEA through the first inlet valve. After permeation through the MEA, the gas enters the anode and flows into the flow meter through the third inlet valve. After passing through the flow meter, it is released to the atmosphere through the third vent valve. Once the gas pressure in the pipeline stabilizes, the flow meter reading is obtained. After testing for several minutes (e.g., 5 minutes), the flow meter reading is checked against the first standard threshold. If it is, the airtightness of the MEA meets the requirements, and the test passes. If not, the airtightness of the MEA does not meet the requirements, and the test fails. After the test is completed, the first inlet valve is closed, and the first and second vent valves are opened to expel excess gas from the pipeline.

[0024] The first standard threshold range is set based on the size of the membrane electrode and the permeability requirements. A larger membrane electrode results in a longer pressure stabilization time, more gas permeates through the membrane electrode, and a higher flow meter reading. In this embodiment, the first standard threshold range is set to 0.6 sccm ± 0.05. After the gas pressure in the pipeline stabilizes, gas is continuously supplied for 60 seconds. If the final flow meter reading is within the range of 0.6 sccm ± 0.05, the test passes; otherwise, the test fails.

[0025] The airtightness test of the bipolar plate essentially checks for external leakage within the cavity containing the bipolar plate. During the test, the first and third inlet valves, the first and second exhaust valves, and the third exhaust valve are closed. Gas in the storage tank, after being depressurized by the pressure reducing unit, passes through the second inlet valve and enters the flow meter and the fourth inlet valve, then into the shared port between the anode of the membrane electrode and the bipolar plate (i.e., the anode of the membrane electrode and the bipolar plate share a single port). Once the gas pressure in the pipeline stabilizes, the fourth inlet valve is closed, and the flow meter reading is recorded. After testing for several minutes (e.g., 5 minutes), it is determined whether the flow meter reading exceeds the second standard threshold. If not, it indicates that there is no external leakage within the cavity containing the bipolar plate, and the test passes; if so, it indicates that there is external leakage within the cavity containing the bipolar plate, and the test fails. After the test is completed, the second inlet valve is closed, and the third exhaust valve is opened to expel excess gas from the pipeline.

[0026] During testing, the cavity containing the bipolar plate is rapidly inflated via the fourth air inlet valve to increase the detection speed. Once the air pressure stabilizes, the fourth air inlet valve is closed, and the flow meter reading is used to determine if there is any external leakage within the cavity containing the bipolar plate. The second standard threshold is set based on the size of the bipolar plate and the airtightness requirements. In this embodiment, the second standard threshold is set to 0.03 sccm; a value exceeding 0.03 sccm indicates an external leakage.

[0027] In a specific embodiment of this invention, the pressure reducing unit includes a first pressure reducing valve and a second pressure reducing valve connected in sequence. Through multi-stage pressure reduction, the stability of the gas supply is ensured.

[0028] In a specific embodiment of this utility model, a first pressure transmitter is also provided on the pipeline between the pressure reducing unit and the second air intake valve. The first pressure transmitter detects the air pressure in the pipeline and determines whether the air pressure in the pipeline is stable during membrane electrode detection based on the air pressure curve. At the same time, the air pressure curve can also help determine whether there is a leak. If the air pressure curve remains within a certain range, it indicates that there is no leak.

[0029] In a specific embodiment of this utility model, a second pressure transmitter is also provided in the pipeline between the flow meter and the anode of the membrane electrode and the common air port of the bipolar plate. The second pressure transmitter detects the air pressure in the pipeline and judges whether the air pressure in the pipeline is stable when the bipolar plate is detected based on the air pressure curve. At the same time, the air pressure curve can also help to judge whether there is a leak. If the air pressure curve remains within a certain range, it indicates that there is no leak.

[0030] In a specific embodiment of this utility model, the airtightness detection device further includes a control module. The first air inlet valve, the second air inlet valve, the third air inlet valve, the fourth air inlet valve, the first exhaust valve, the second exhaust valve, and the third exhaust valve are respectively connected to the control module. The control module controls the opening and closing of each valve, which can realize automatic detection and one-click switching between membrane electrode and bipolar plate detection, improve detection efficiency, and save time and manpower.

[0031] In a specific embodiment of this utility model, a safety valve is provided on the gas storage tank. The safety valve improves the safety of gas use and prevents excessive gas in the gas storage tank.

[0032] In a specific embodiment of this utility model, a filter is provided on the pipeline between the gas storage tank and the pressure reducing unit. The filter removes impurities in the gas, thus preventing contamination of the pipeline by impurities.

[0033] In a specific embodiment of this utility model, the gas storage tank is also connected to an external gas source through a triplet. By filling the gas storage tank with gas through the triplet, the gas fluctuations at the front end can be stabilized.

[0034] The above description only discloses specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A gas tightness detection device compatible with air-cooled fuel cell stack membrane electrodes and bipolar plates, characterized in that: The airtightness testing device includes an air tank, a pressure reducing unit, a first air inlet valve, a second air inlet valve, a third air inlet valve, a fourth air inlet valve, a first exhaust valve, a second exhaust valve, a third exhaust valve, and a flow meter; The gas storage tank is connected to the first and second inlet valves through a pressure reducing unit. The first inlet valve is connected to the cathode end of the membrane electrode. The second inlet valve is connected to the third and fourth inlet valves and the common air port of the anode end of the membrane electrode and the bipolar plate. The third inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate. The fourth inlet valve is also connected to the common air port of the anode end of the membrane electrode and the bipolar plate. The first exhaust valve is located on the pipeline between the first intake valve and the cathode end of the membrane electrode; the second exhaust valve is located on the pipeline between the third intake valve and the anode end of the membrane electrode and the common air port of the bipolar plate; the flow meter is located on the pipeline between the second intake valve and the anode end of the membrane electrode and the common air port of the bipolar plate; and the third exhaust valve is located on the pipeline between the flow meter and the anode end of the membrane electrode and the common air port of the bipolar plate.

2. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to claim 1, characterized in that: The pressure reducing unit includes a first pressure reducing valve and a second pressure reducing valve connected in sequence.

3. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to claim 1, characterized in that: A first pressure transmitter is also provided on the pipeline between the pressure reducing unit and the second intake valve.

4. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to claim 1, characterized in that: A second pressure transmitter is also provided in the pipeline between the flow meter and the anode of the membrane electrode and the common air port of the bipolar plate.

5. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to claim 1, characterized in that: The airtightness detection device also includes a control module, and the first air intake valve, the second air intake valve, the third air intake valve, the fourth air intake valve, the first exhaust valve, the second exhaust valve, and the third exhaust valve are respectively connected to the control module.

6. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to claim 1, characterized in that: A safety valve is installed on the gas storage tank.

7. The airtightness detection device compatible with air-cooled fuel cell stack film electrode and bipolar plate according to claim 1, characterized in that: A filter is installed on the pipeline between the gas storage tank and the pressure reducing unit.

8. The airtightness detection device compatible with air-cooled fuel cell membrane electrodes and bipolar plates according to any one of claims 1 to 7, characterized in that: The gas storage tank is also connected to an external gas source via a triplet.

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