A bipolar plate sealing detection device and detection method

Abstract

The application discloses a bipolar plate sealing detection device and a detection method, and solves the technical problem of low sealing detection efficiency of the bipolar plate in the prior art. The bipolar plate sealing detection device comprises an upper workbench, a lower workbench, a plurality of test units and at least one detection unit, the plurality of test units are arranged at intervals on the lower workbench, and the upper workbench is operable to compress the plurality of test units with the lower workbench; the test unit comprises an upper pressing plate, a lower pressing plate and a plurality of ultrasonic probes, the upper pressing plate and the lower pressing plate can jointly clamp a plurality of bipolar plates, one end of the lower pressing plate is provided with a plurality of air inlet holes, the air inlet holes and flow channel openings of the bipolar plates form test channels, and the plurality of ultrasonic probes are arranged on the circumferential side of the lower pressing plate; and the detection unit is in communication with the plurality of test channels of at least two test units. A bipolar plate sealing detection method is applied to the bipolar plate sealing detection device. The application can detect the bipolar plates in batches, and has high test efficiency and high test accuracy.

Description

Technical Field

[0001] This application belongs to the field of bipolar plate testing technology, specifically relating to a bipolar plate sealing testing device and testing method. Background Technology

[0002] Bipolar plates are the core components of fuel cells. They are usually made of stainless steel sheets with a thickness of 0.07 to 0.1 mm, which are stamped into cathode and anode plates with microchannels. Two unipolar plates are welded or bonded together to form a bipolar plate structure with "two plates and three fields".

[0003] Before applying bipolar plates to fuel cells, each bipolar plate needs to undergo a sealing test. Typically, a bonding line is laid on a bipolar plate (or endplate) to be tested. The bipolar plate is then placed between the upper and lower endplates, and the endplates are closed under pressure, forming a sealed chamber on the bipolar plate and its sides. Test gas at a certain pressure is then sequentially introduced into the three chambers of the bipolar plate. After maintaining this pressure for a certain period, if the pressure drop (or leakage) is less than the required value, the bipolar plate is considered to have passed the sealing test. This testing method is extremely inefficient and cannot meet the current and future production needs of fuel cell vehicles. Summary of the Invention

[0004] To address the current technical problem of low efficiency in testing the sealing performance of bipolar plates, in the first aspect of this application, a bipolar plate sealing performance testing device is provided, comprising an upper worktable, a lower worktable disposed below the upper worktable, a plurality of test units and at least one detection unit, wherein the plurality of test units are spaced apart on the lower worktable, and the upper worktable is operably pressed against the lower worktable to press the plurality of test units.

[0005] The test unit includes:

[0006] An upper pressure plate is provided on the upper worktable;

[0007] A lower pressure plate is provided on the lower worktable. The upper pressure plate and the lower pressure plate can operably clamp multiple bipolar plates together. One end of the lower pressure plate is provided with multiple air inlets corresponding to the flow channels of the bipolar plates.

[0008] Multiple auxiliary test boards are provided, each having multiple auxiliary flow channels corresponding to the flow channels of the bipolar plate. The multiple auxiliary test boards and the multiple bipolar plates are stacked alternately between the upper pressure plate and the lower pressure plate. The multiple air inlets are respectively connected to the multiple flow channels of the stacked bipolar plates and the multiple auxiliary flow channels of the auxiliary test boards to form multiple test channels.

[0009] Multiple ultrasonic probes are disposed on the periphery of the lower pressure plate;

[0010] The detection unit is connected to at least one of the multiple test channels of the two test units.

[0011] In some embodiments, sealing rings are provided between the upper pressure plate and the bipolar plate, between the lower pressure plate and the bipolar plate, and between the auxiliary test plate and the bipolar plate.

[0012] In some embodiments, the test unit further includes an elastic element disposed between the lower pressure plate and the lower worktable in a compressed state.

[0013] In some embodiments, each of the test units includes at least four ultrasonic probes distributed around the bipolar plate.

[0014] In some embodiments, the bipolar plate sealing test device further includes an isolation cover, which is detachably mounted on the lower pressure plate. The isolation cover has multiple enclosed isolation cavities, and the multiple test units are correspondingly located in the isolation cavities.

[0015] In some implementations, the plurality of test units are arranged in a matrix;

[0016] The isolation cover includes a cover body and at least one transverse partition and at least one longitudinal partition disposed within the cover body. The transverse partition and the longitudinal partition are cross-connected to divide the inner cavity of the cover body into a plurality of isolation cavities.

[0017] In some embodiments, each of the test units has an air inlet connected to an air inlet pipe, and at least two of the air inlet pipes are connected to the same main air inlet pipe. A flow meter is provided on the air inlet pipe or the main air inlet pipe.

[0018] In a second aspect of this application, a bipolar plate sealing performance testing method is provided, applied to the aforementioned bipolar plate sealing performance testing device.

[0019] (1) The multiple sets of bipolar plates to be tested are respectively placed in the multiple test units of the bipolar plate sealing test device;

[0020] (2) Test gas is continuously introduced into the test channel of each test unit to a set pressure, and the bipolar plate of the multiple test units connected to the detection unit is detected to see if leakage occurs.

[0021] (3) Determine the bipolar plate group in which the leaking bipolar plate is located among the multiple test units connected to the detection unit based on the detection signal of the ultrasonic probe;

[0022] (4) Divide the bipolar plate group containing the leaking bipolar plate into multiple bipolar plate sub-units, and place them into multiple test units respectively;

[0023] (5) Repeat steps (2) to (4) until a leaking bipolar plate is identified.

[0024] In some embodiments, after determining the leaking bipolar plate in step (5), the bipolar plate sealing detection method further includes: determining the leakage location of the leaking bipolar plate based on the detection signal of the ultrasonic probe.

[0025] In some implementations, step (2), which involves detecting whether the bipolar plates of the plurality of test units connected to the detection unit are leaking, specifically includes:

[0026] Test gas is continuously introduced into the test channel of each test unit.

[0027] The flow rate of the test gas is obtained through the detection unit;

[0028] Based on the obtained flow rate of the test gas, it is determined whether the bipolar plates of the multiple test units are leaking.

[0029] In some implementations, step (2), which involves detecting whether the bipolar plates of the plurality of test units connected to the detection unit are leaking, specifically includes:

[0030] The test channel is a closed cavity;

[0031] The air pressure value of the test channel is obtained through the detection unit;

[0032] Based on the obtained air pressure value of the test channel, it is determined whether the bipolar plates of the multiple test units have leaked. The bipolar plate sealing performance testing device and method provided according to one or more embodiments of this application have the following technical effects:

[0033] (1) The bipolar plate sealing test device and test method provided according to one or more embodiments of this application greatly increases the number of bipolar plates that can be tested in a single test by setting multiple test units between the upper worktable and the lower worktable. The efficiency of bipolar plate sealing test is improved by the test unit connected to multiple test units, realizing batch and rapid testing of bipolar plate sealing and improving test efficiency.

[0034] (2) According to one or more embodiments of this application, the bipolar plate sealing test device and test method can locate the bipolar plate unit with the leaking bipolar plate by means of multiple ultrasonic probes set on the periphery of the lower pressure plate. At the same time, multiple ultrasonic probes set along the periphery of the lower pressure plate can also accurately locate the location of the leaking bipolar plate, which helps the operator to determine whether the leaking bipolar plate is caused by the manufacturing process of the bipolar plate. Attached Figure Description

[0035] Figure 1 A schematic diagram of the bipolar plate in one or more embodiments of this application is shown.

[0036] Figure 2 A schematic diagram of the structure of a bipolar plate sealing performance testing device in one or more embodiments of this application is shown.

[0037] Figure 3 It shows Figure 2 A schematic diagram of the bipolar plate sealing test device from another perspective.

[0038] Figure 4 It shows Figure 3 A schematic diagram of the structure of the bipolar plate and the auxiliary test plate.

[0039] Figure 5 It shows Figure 4 A schematic diagram of the auxiliary test board.

[0040] Figure 6 It shows Figure 2 Schematic diagram of the middle and lower pressure plates.

[0041] Figure 7 It shows Figure 6 Schematic diagram of the cross-sectional structure along the AA direction.

[0042] Figure 8 It shows Figure 2 A schematic diagram of the structure of the central isolation enclosure.

[0043] Figure 9 A flowchart illustrating a bipolar plate sealing test method in one or more embodiments of this application is shown.

[0044] Explanation of reference numerals in the attached drawings: 1-Bipolar plate, 11-Bipolar plate flow channel, 12-Positioning hole, 2-Upper worktable, 3-Lower worktable, 4-Test unit, 41-Upper pressure plate, 42-Lower pressure plate, 421-Air inlet, 43-Ultrasonic probe, 44-Auxiliary test plate, 441-Second positioning hole, 5-Detection unit, 6-Air inlet pipe, 7-Sealing ring, 8-Compression spring, 9-Isolation cover, 91-Transverse partition, 92-Longitudinal partition, 93-Bolt, 10-Hydraulic mechanism. Detailed Implementation

[0045] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0046] See Figure 1 Three flow channels are provided at both ends of the bipolar plate 1 along its length, and the three flow channels at both ends of the bipolar plate 1 are symmetrical about the center of the bipolar plate 1. A bipolar plate flow channel 11 is provided in the middle of the bipolar plate 1, and positioning holes 12 are provided around the bipolar plate 1 to facilitate assembly. After multiple bipolar plates 1 and membrane electrodes are stacked in an alternating manner, the three flow channels on the same side form a hydrogen cavity, an air cavity, and a water cavity, respectively.

[0047] Existing testing devices for bipolar plates include an upper end plate, a lower end plate, and a worktable that drives the upper and lower end plates to close. Since a single bipolar plate is relatively thin, both the upper and lower end plates have vent holes. One vent hole is connected to the test gas, and the other vent hole is connected to a pressure gauge to obtain the air pressure inside the testing device after the mold is closed. This allows for the judgment of whether the sealing performance of the single bipolar plate meets the requirements. The testing time for a single bipolar plate is approximately 1-2 minutes, which is significantly inefficient.

[0048] Figure 1 A schematic diagram of the bipolar plate in one or more embodiments of this application is shown. Figure 2 A schematic diagram of the structure of a bipolar plate sealing performance testing device in one or more embodiments of this application is shown. Figure 3 It shows Figure 2 A schematic diagram of the bipolar plate sealing test device from another perspective. Figure 4 It shows Figure 3 A schematic diagram of the structure of the bipolar plate and the auxiliary test plate. Figure 5 It shows Figure 4 A schematic diagram of the auxiliary test board. Figure 6 It shows Figure 2 Schematic diagram of the middle and lower pressure plates. Figure 7 It shows Figure 6 Schematic diagram of the cross-sectional structure along the AA direction. Figure 8 It shows Figure 2 A schematic diagram of the structure of the central isolation enclosure. Figure 9 A flowchart illustrating a bipolar plate sealing test method in one or more embodiments of this application is shown.

[0049] Please see Figure 1-8According to a first aspect of this application, a bipolar plate sealing performance testing device (hereinafter referred to as the testing device) is provided. The testing device includes an upper worktable 2, a lower worktable 3, a plurality of testing units 4, and at least one testing unit.

[0050] The lower workbench 3 is the basic element for placing multiple test units 4. The upper workbench 2 is located above the lower workbench 3. The lower workbench 3 is located on the ground or other working platform. The upper workbench 2 can be connected to the lower workbench 3 by a bracket, or it can be located on the ground or other working platform and erected above the lower workbench 3 by a bracket. Multiple test units 4 are located at the top of the lower workbench 3 and are spaced apart.

[0051] See Figure 2 , Figure 3 and Figure 6 The testing unit 4 includes an upper pressure plate 41, a lower pressure plate 42, and an ultrasonic probe 43. The upper pressure plate 41 is located on the upper worktable 2, and the lower pressure plate 42 is located on the lower worktable 3. The lower pressure plate 42 is positioned below the upper pressure plate 41, and multiple bipolar plates 1 are placed between the upper pressure plate 41 and the lower pressure plate 42. The upper pressure plate 41 can be located on the bottom surface of the upper worktable 2, and correspondingly, the lower pressure plate 42 can be located on the top surface of the lower worktable 3, which facilitates installation and maintenance.

[0052] See Figure 4 and Figure 6 The test unit 4 also includes an auxiliary test board 44. The auxiliary test board 44 is provided with multiple auxiliary flow channels corresponding to the flow channels of the bipolar plate 1. The layout of the auxiliary flow channels of the auxiliary test board 44 is consistent with that of the bipolar plate 1 to be tested, so that the auxiliary test board 44 can be used to simulate the membrane electrode to reduce the test cost.

[0053] See Figure 3 Multiple auxiliary test plates 44 and multiple bipolar plates 1 are stacked and staggered in a cubic shape and placed between the upper pressure plate 41 and the lower pressure plate 42. The flow channels on the multiple bipolar plates 1 and the multiple corresponding auxiliary flow channels form multiple test channels. Of course, the size of the auxiliary flow channels can correspond one-to-one with the size of the flow channels on the bipolar plates 1 to ensure that there are no obvious obstruction structures in the test channels and improve the accuracy of the test.

[0054] See Figure 3 and Figure 4 The upper worktable 2 can be operably pressed against the lower worktable 3 to clamp multiple test units 4. That is, by driving the upper worktable 2 and / or the lower worktable 3 to move, the upper pressure plate 41 and the lower pressure plate 42 can operably clamp multiple bipolar plates 1 and multiple auxiliary test plates 44 together. The drive mechanism for driving the upper worktable 2 and / or the lower worktable 3 to move can be selected as multiple hydraulic mechanisms 10 to ensure that the multiple test units 4 are subjected to consistent force.

[0055] Of course, the drive mechanism can also be located between the upper worktable 2 and the upper pressure plate 41 and / or between the lower worktable 3 and the lower pressure plate 42. That is, multiple test units 4 are relatively independent. Multiple test units 4 can be tested simultaneously or individually. While improving efficiency, it also increases the degree of freedom of the testing device. It is convenient for operators to customize the number of test units 4 to be tested, and to control the distance between the upper pressure plate 41 and the lower pressure plate 42 in different test units 4 during the test. That is, the number of bipolar plates 1 and auxiliary test plates 4 between each test unit 4 has little impact on the accuracy of the test.

[0056] See Figure 6 and Figure 7 The lower pressure plate 42 has multiple air inlets 421 at one end. The number and position of the air inlets 421 correspond one-to-one with the test channels on the same end of the bipolar plate 1, so as to perform sealing tests on the different test channels formed by stacking multiple bipolar plates 1.

[0057] After the testing device clamps multiple bipolar plates 1 to be tested, there are six test channels between the multiple bipolar plates 1. Two test channels that are centrally symmetrical are connected through the bipolar plate flow channel 11 of the bipolar plate 1. Except for the air inlet 421, the test channels of the multiple bipolar plates 1 between the upper pressure plate 41 and the lower pressure plate 42 form a sealed cavity.

[0058] Leaking bipolar plates are bipolar plates 1 that do not meet the sealing requirements. During multiple testing operations, the operators found that the proportion of leaking bipolar plates was not large. Therefore, one detection unit 5 is connected to multiple test channels of at least two test units 4. One detection unit 5 can simultaneously measure the sealing performance of multiple bipolar plates 1 in multiple test units 4, which greatly increases the number of bipolar plates 1 that the detection device can test in the same batch and improves the testing efficiency.

[0059] See Figure 6Multiple ultrasonic probes 43 are located on the periphery of the lower pressure plate 42. When the sealing performance of the bipolar plate 1 with test unit 4 is found to be unsatisfactory, the ultrasonic probes 43 are activated to more accurately determine the test unit 4 that has leaked. Specifically, by identifying which ultrasonic probes 43 detect the strongest signals, the specific test unit 4 can be located to pinpoint the leak. Furthermore, by adjusting the number and position of the ultrasonic probes 43, the approximate location of the leaking bipolar plate within the test unit 4 can be more accurately determined. Because multiple ultrasonic probes 43 are positioned around the lower pressure plate 42, after detecting a leaking bipolar plate, the direction of the leak can be obtained through the signals detected by the ultrasonic probes 43. This helps operators determine whether the manufacturing process of the bipolar plate 1 resulted in a failure to maintain its seal. Factors affecting the seal of the bipolar plate 1 during manufacturing include incoming materials, manufacturing methods, operator procedures, equipment welding or bonding processes, and the working environment. Once the direction of the leak is determined, operators can comprehensively assess the cause of the leak based on its location, thereby improving the overall pass rate of the bipolar plate 1 production line. For example, if multiple leaking bipolar plates leak from the same location, it may be due to poor welding or bonding processes at that location; if the leaking locations of multiple leaking bipolar plates are different, it may be due to substandard sealing of bipolar plate 1 caused by incoming materials or the working environment.

[0060] In summary, by using at least one detection unit 5 and multiple test units 4, multiple bipolar plates 1 can be simultaneously tested for sealing performance, significantly improving the testing efficiency.

[0061] Meanwhile, the testing device does not need to open vent holes on the upper pressure plate 41, reducing the number of through holes in the test unit 4, reducing the variables affecting the test accuracy, and the test accuracy will be greatly improved.

[0062] Of course, in order to quickly install the bipolar plate 1 and the auxiliary test plate 44, the length and width of the auxiliary test plate 44 are consistent with the bipolar plate 1 to be tested, and the auxiliary test plate 44 is provided with second positioning holes 441 that match the positioning holes 12 around its perimeter. The bipolar plate 1 and the auxiliary test plate 44 can be positioned by the same positioning rod, and the assembly efficiency of the bipolar plate 1 and the auxiliary test plate 44 is high.

[0063] See Figure 4 and Figure 5 In some embodiments, sealing rings 7 are provided between the upper pressure plate 41 and the bipolar plate 1, between the lower pressure plate 42 and the bipolar plate 1, and between the auxiliary test plate 44 and the bipolar plate 1.

[0064] See Figure 5The sealing ring 7 is provided with a second auxiliary flow channel corresponding to the flow channel opening of the bipolar plate 1. The size of the second auxiliary flow channel opening is not smaller than the size of the flow channel opening of the bipolar plate 1. The sealing ring 7 improves the sealing performance of the test channel, allowing the test gas to move only within the test channel, thus improving the accuracy of the test. Correspondingly, the volume of test gas required to fill the test channel is small, and the test channel can be filled quickly, allowing for faster acquisition of test data and improving test efficiency. At the same time, the bottom surface of the upper pressure plate 41 and the top surface of the lower pressure plate 42 need to be kept parallel. However, after multiple tests, there may be a certain angle between the bottom surface of the upper pressure plate 41 and the top surface of the lower pressure plate 42. By setting multiple sealing rings 7, the characteristics of the sealing rings 7 can effectively eliminate the influence of the angle between the bottom surface of the upper pressure plate 41 and the top surface of the lower pressure plate 42, still ensuring that the multiple bipolar plates 1 and the auxiliary test plate 44 are all in a compressed state.

[0065] The sealing ring 7 can be set separately. When placing the bipolar plate 1 in the test unit 4, the sealing ring 7, bipolar plate 1, sealing ring 7, auxiliary test plate 44, and sealing ring 7 are placed in sequence. Of course, in order to improve the efficiency of placing the bipolar plate 1, the sealing ring 7 can be set on the bottom surface of the upper pressure plate 41, the top surface of the lower pressure plate 42, and the top and bottom surfaces of the auxiliary test plate 44 by adhesive bonding. Alternatively, grooves can be made at corresponding positions on the bottom surface of the upper pressure plate 41, the top surface of the lower pressure plate 42, and the top and bottom surfaces of the auxiliary test plate 44, so that the top or bottom end of the sealing ring 7 is fitted into the groove by interference fit. This makes it convenient for operators to regularly inspect and replace the sealing performance of the sealing ring 7. Of course, since the auxiliary test plate 44 is relatively thin, the sealing ring 7 can also be set on the surface of the auxiliary test plate 44 by injection molding.

[0066] In some embodiments, an elastic element is provided between the lower pressure plate 42 and the lower worktable 3. The elastic element is located between the lower worktable 3 and the lower pressure plate 42 in a compressed state, meaning that the elastic element has the ability to return to its natural state. The elastic element can adjust the position of the lower pressure plate 42 to a certain extent. (See reference...) Figure 3 In some embodiments, the elastic element is a compression spring 8, the axis of which is parallel to the moving direction of the upper worktable 2 or the lower worktable 3 that holds the test unit 4, and the compression spring 8 is in a compressed state and can continue to be compressed.

[0067] During multiple tests, there may be a certain angle between the bottom surface of the upper pressure plate 41 and the top surface of the lower pressure plate 42. The compression spring 8 can not only be compressed or stretched in its axial direction, but also be bent. Therefore, when the upper pressure plate 41 and the lower pressure plate 42 jointly clamp multiple bipolar plates 1 and multiple auxiliary test plates 44, the compression spring 8 is compressed and can be bent to a certain extent. At this time, under the combined action of the compression spring 8 and the upper pressure plate 41, the position of the top surface of the lower pressure plate 42 will change and eventually become parallel to the bottom surface of the upper pressure plate 41. This can effectively eliminate the influence of the angle between the bottom surface of the upper pressure plate 41 and the top surface of the lower pressure plate 42, and still ensure that the multiple bipolar plates 1 and the auxiliary test plates 44 are all in a compressed state.

[0068] In each test unit 4, the number of elastic elements can be 1, 2, 3, 4, etc. The more elastic elements there are, the higher the stability of the lower pressure plate 42 on the lower worktable 3, and the longer the service life of the elastic elements can be.

[0069] Of course, to avoid the working environment affecting the compression spring 8, please refer to... Figure 3 The top surface of the lower workbench 3 can be provided with a first mounting hole, and the bottom surface of the lower pressure plate 42 can be provided with a corresponding second mounting hole. Both the first mounting hole and the second mounting hole are blind holes. The opposite ends of the compression spring 8 are connected to or abut against the bottom of the first mounting hole and the second mounting hole, respectively, reducing the part of the compression spring 8 exposed to the working environment.

[0070] See Figure 2 and Figure 6 In some embodiments, each test unit 4 includes at least four ultrasonic probes 43, arranged in pairs along the axis of symmetry of the lower pressure plate 42, and at least one ultrasonic probe 43 is provided on each side of the lower pressure plate 42. The bipolar plate 1 is rectangular, and the lower pressure plate 42 is also rectangular. Thus, by providing at least four ultrasonic probes 43, it is ensured that each side of the test unit 4 has at least one ultrasonic probe 43, thereby improving the efficiency and accuracy of the detection.

[0071] See Figure 1 Considering the relatively long length of bipolar plate 1, therefore, refer to Figure 6In some embodiments, each test unit 4 includes six ultrasonic probes 43, with two ultrasonic probes 43 located in the middle of the width direction of the lower pressure plate 42, two other ultrasonic probes 43 equally spaced on one side of the length direction of the lower pressure plate 42, and the last two ultrasonic probes 43 equally spaced on the other side of the length direction of the lower pressure plate 42. This increases the coverage of the detection range of the test unit 4 by the ultrasonic probes 43, thereby improving the accuracy of the test. Simultaneously, the two ultrasonic probes 43 located in the width direction of the lower pressure plate 42 can determine which end of the bipolar plate 1 is leaking, while the four ultrasonic probes 43 located in the length direction of the lower pressure plate 42 can determine which side of the bipolar plate 1 is leaking. By comparing the signal magnitudes obtained by the two ultrasonic probes 43 on the same side, the specific location of the leaking bipolar plate—whether it is in the cavity, hydrogen cavity, or water cavity—can be further determined.

[0072] Although multiple test units 4 are spaced apart, adjacent test units 4 still have ultrasonic probes 43 that are relatively close together. Therefore, refer to Figure 2 In some embodiments, the bipolar plate 1 sealing test device further includes an isolation cover 9, which is detachably mounted on the lower pressure plate 42. The isolation cover 9 has multiple enclosed isolation chambers, and multiple test units 4 are arranged one-to-one within the isolation chambers. Separating the test units 4 can reduce the influence between adjacent test units 4, and the fact that there is no airflow or the airflow rate is very small within the enclosed isolation chambers can significantly improve the accuracy of the ultrasonic probe 43.

[0073] Specifically, the isolation cover 9 can be installed on the lower pressure plate 42 before using the ultrasonic probe 43. The isolation cover 9 can have a telescopic structure to accommodate multiple test units 4. Of course, isolation covers 9 of various heights can also be customized to accommodate different numbers of bipolar plates 1 and auxiliary detection plates 44.

[0074] After placing multiple bipolar plates 1 and multiple auxiliary detection plates on the lower pressure plate 42, the isolation cover 9 is installed on the lower pressure plate 42. When the isolation cover 9 is placed between the upper pressure plate 41 and the lower pressure plate 42, the height of the isolation cover 9 must be equal to or slightly less than the height of the multiple bipolar plates 1 and multiple auxiliary detection plates after being compressed. When the isolation cover 9 is placed between the upper worktable 2 and the lower worktable 3, the height of the isolation cover 9 is equal to or slightly less than the distance between the upper worktable 2 and the lower worktable 3 when the multiple bipolar plates 1 and multiple auxiliary detection plates are compressed.

[0075] See Figure 2Multiple test units 4 are arranged in a matrix, resulting in more uniform force distribution across each test unit 4. Correspondingly, the isolation cover 9 may include a cover body and at least one transverse partition and at least one longitudinal partition disposed within the cover body. The transverse partition and the longitudinal partition are cross-connected to divide the inner cavity of the cover body into multiple isolation chambers. The cover body includes multiple door panels, each door panel being detachably connected to the end of a transverse partition or a longitudinal partition via a sealing element. Each door panel can be individually connected to a transverse partition or a longitudinal partition, facilitating operation of the test units 4 by personnel.

[0076] In some embodiments, the isolation cover 9 may also include a plurality of transverse partitions 91, some of which are provided with longitudinal partitions 92. After the plurality of transverse partitions 91 are connected, the transverse partitions 91 and the longitudinal partitions 92 enclose an isolation cavity.

[0077] Specifically, see Figure 8 Multiple transverse partitions 91 may include two side plates and one middle plate. Multiple longitudinal partitions 92 are equally spaced on the opposite sides of the two side plates. The transverse partitions 91 and longitudinal partitions 92 are of the same height and their bottom ends are flush. After the middle plate is inserted into the middle of multiple test units 4, the side plates are moved closer to the middle plate from both sides. When the ends of the longitudinal partitions 92 abut against the middle plate, the two side plates and the middle plate are locked together by bolts 93.

[0078] The detection unit 5 can be a leak detector, flow meter, pressure gauge, etc., and this application is not limited thereto. In some embodiments, the detection unit 5 includes a gas storage device and a flow meter. The gas storage device has a built-in pressure gauge so that the gas storage device can introduce test gas at a rated pressure into the test channel. One end of the air inlet 421 is connected to the test channel, and the other end of the air inlet 421 is connected to the test gas storage device through the air inlet pipe 6. A flow meter is installed on the air inlet pipe 6 to obtain the flow rate of the test gas in the air inlet pipe 6. The flow meter may have a display screen or pointer to visualize the flow data, or it may be electrically connected to a digital terminal to transmit the obtained flow data to the digital terminal for display.

[0079] During the test, as time progresses, the test gas will fill multiple test channels. At this point, the test gas can no longer enter the test channels, and the flow meter reading should be 0 or close to 0. By reading the flow data obtained from the flow meter, it can be determined whether there is a problem with the sealing of the multiple test units 4 using the inlet pipe 6.

[0080] When the flow meter reading is 0 after a set time or the flow data is within the rated range, it can be determined that the sealing performance of the multiple bipolar plates 1 of the test unit 4 connected to the inlet pipe 6 where the flow meter is located meets the requirements.

[0081] If the flow meter reading is not 0 after a set time or the flow data exceeds the rated range, it can be determined that the sealing performance of the multiple bipolar plates 1 of the test unit 4 connected to the inlet pipe 6 where the flow meter is located does not meet the requirements.

[0082] In some embodiments, the bipolar plate 1 sealing test device includes at least two main air inlet pipes, each main air inlet pipe being connected to at least two air inlet pipes 6, and a flow meter is installed in the main air inlet pipe. Considering the finished product yield of the bipolar plate 1, refer to... Figure 2 The test units 4 are divided into two groups, each group is connected to the same intake manifold, which can greatly reduce the number of tests and identify the bipolar plate 1 in the test unit 4 with substandard sealing performance, resulting in high testing efficiency.

[0083] In some embodiments, the detection unit 5 includes a gas storage device and a pressure gauge, the gas storage device having a built-in valve. After the test gas is introduced into the test channel, the gas storage device is closed, and the pressure value in the test channel is obtained through the pressure gauge. The pressure gauge may have a display screen or pointer to visualize the pressure value data, or it may be electrically connected to a digital terminal to transmit the obtained flow data to the digital terminal for display.

[0084] The bipolar plate sealing performance testing device provided according to one or more of the above embodiments has the following technical effects:

[0085] 1. The bipolar plate sealing performance testing device has multiple pairs of upper and lower pressure plates installed on the upper worktable 2 and lower worktable 3. Multiple bipolar plates 1 to be tested and auxiliary test plates 44 are alternately stacked between each pair of upper and lower pressure plates, and a sealing effect is achieved under the action of the sealing ring 7. This enables batch and rapid testing of the sealing performance of bipolar plates 1, improving testing efficiency.

[0086] 2. Each test unit 4 is equipped with a set of ultrasonic probes 43. The isolation covers 9 separate each group of bipolar plates 1 and their ultrasonic probes 43, allowing for more accurate identification of the leak group. Furthermore, the strongest signal detected by a particular ultrasonic probe 43 around the leaking group can pinpoint the leaking area of ​​that group of bipolar plates 1, providing support for improving poor welding or bonding seals of the bipolar plates 1. If a certain area experiences frequent leaks, it indicates that defects such as incomplete welding, burn-through, or weak bonding are prone to occur in the welding or bonding process of the bipolar plates 1. This suggests the need to investigate whether there are any abnormalities in the welding or bonding process parameters, fixtures, or deformation of the bipolar plates 1 in that area, providing support for improving the welding or bonding process.

[0087] Based on the same inventive concept, please refer to Figure 9 According to a second aspect of this application, a bipolar plate sealing performance testing method is provided, applied to the above-mentioned bipolar plate sealing performance testing device, comprising the following steps:

[0088] Step 100: Place the multiple sets of bipolar plates to be tested into multiple test units of the bipolar plate sealing test device.

[0089] Multiple bipolar plates 1 set in the same test unit 4 constitute a bipolar plate group. When the upper workbench 2 and the lower workbench 3 perform operations on multiple test units 4 at the same time, the number of bipolar plates 1 in each bipolar plate group is the same. During testing, the height of each group of bipolar plates 1 is the same or close, and the testing accuracy of each group of test units 4 is high.

[0090] Step 200: Test gas is continuously introduced into the test channel of each test unit 4 to the set pressure, and the bipolar plate 1 of the multiple test units 4 connected to the detection unit 5 is detected to see if there is any leakage.

[0091] Step 300: Based on the detection signal of the ultrasonic probe 43, determine the bipolar plate group where the leaking bipolar plate is located in the multiple test units 4 connected to the detection unit 5, and obtain the bipolar plate 1 in the test unit 4 that does not meet the sealing requirements.

[0092] In step 200, before the detection unit 5 is tested, a pressure holding step can be performed on each test unit 4 to improve the accuracy of the test.

[0093] In steps 200 and 300, multiple bipolar plate assemblies undergo sealing tests simultaneously. Each detection unit 5 is connected to at least two test units 4, meaning that one detection unit 5 can detect whether a leaking bipolar plate exists in the test unit 4 it is connected to. Then, in step 300, the ultrasonic probe 43 further locates which test units 4 have leaking bipolar plates. The ultrasonic probe 43 can be activated simultaneously with the step in step 200 where test gas is continuously introduced to a set pressure. This shortens the testing time and allows for real-time acquisition of the gas pressure value in the test channel when a leaking bipolar plate occurs, providing clues for operators to analyze the cause of the leak in bipolar plate 1 while identifying the leaking bipolar plate.

[0094] Step 400: Divide the bipolar plate group containing the leaking bipolar plate into multiple bipolar plate sub-units, and place them into multiple test units 4 respectively. Perform the bipolar plate sealing test method again until the leaking bipolar plate is identified.

[0095] Specifically, the bipolar plate 1 in the test unit 4 that passed the sealing test is removed and stored. The bipolar plate 1 in the multiple bipolar plate groups that failed the sealing test is divided into multiple bipolar plate sub-units and reassembled into multiple groups of bipolar plate groups with testing. The steps are repeated to allow the testing device to test again. Steps 200-400 are repeated until all the bipolar plates 1 that have leaked are obtained.

[0096] Multiple bipolar plate subunits may include one or more bipolar plates 1. When multiple bipolar plates 1 in a bipolar plate group cannot be evenly divided into multiple bipolar plate subunits, some bipolar plates 1 can be extracted from a bipolar plate group with qualified sealing and added to a bipolar plate subunit, so that multiple test units 4 are highly consistent during testing, thereby improving the accuracy of each test unit 4.

[0097] Depending on the detection device, step 200 may include the following two methods. In some embodiments, the detection unit 5 includes a gas storage device and a flow meter, then the method of step 200 may be as follows:

[0098] Step 210: Test gas is continuously introduced into the test channel of each test unit 4.

[0099] Step 211: Obtain the flow rate of the test gas through the detection unit 5.

[0100] Step 212: Based on the obtained flow rate of the test gas, determine whether the bipolar plate 1 of the multiple test units 4 has leaked.

[0101] The gas storage device is equipped with a pressure gauge so that the gas storage device can introduce test gas at the rated pressure into the test channel, and the flow meter is used to obtain the flow rate of the test gas in the inlet pipe 6.

[0102] Through multiple tests, operators can determine approximately how long it takes for the test channel to fill. This time is designated as the rated time. If the flow meter still shows a reading after the rated time has passed, and the drop in reading is not significant, then the bipolar plate assembly in test unit 4 connected to the flow meter is considered to have a leaking bipolar plate. Alternatively, a pressure-holding step can be added. Specifically, after the rated time has passed, a pressure-holding time is extended. During this time, the output of the gas storage device remains open, allowing test gas to continue entering the test channel. After the pressure-holding time, step 211 is then performed to improve test accuracy.

[0103] In some embodiments, the detection unit 5 includes a gas storage device and a pressure gauge, then step 200 can be performed as follows:

[0104] Step 220: Make the test channel a closed cavity.

[0105] Step 221: Obtain the air pressure value of the test channel through the detection unit 5;

[0106] Step 222: Based on the obtained air pressure value of the test channel, determine whether the bipolar plates of the multiple test units 4 have leaked.

[0107] The detection unit 5 includes a gas storage device and a pressure gauge, with the gas storage device having its own valve. After the test gas is introduced into the test channel to the rated pressure, the valve of the gas storage device is closed. The pressure value in the test channel is then measured by the pressure gauge to see if there is a change. If the value displayed on the pressure gauge decreases and exceeds the set value, it can be considered that the bipolar plate assembly in the test unit 4 connected to the pressure gauge has a leaking bipolar plate. Of course, a pressure holding step can be added during the test. Specifically, when the valve is closed and the gas supply to the test channel is stopped, the valve's operation will cause gas pressure fluctuations in the test channel, making the pressure difference in the test channel unstable. Therefore, a pressure holding step is used to delay the test for a period of time until the pressure difference stabilizes. After the pressure holding step, the test is then performed by the detection unit 5.

[0108] In some implementations, the method further includes step 401: after identifying the leaking bipolar plate, determining the leak location of the leaking bipolar plate based on the detection signal from the ultrasonic probe 43.

[0109] Specifically, multiple ultrasonic probes 43 are located around the lower pressure plate 42. After detecting a leaking bipolar plate, the direction of leakage can be obtained through the signals detected by the ultrasonic probes 43. This helps operators analyze whether the failure to seal the bipolar plate 1 is due to the manufacturing process. The factors affecting the sealing performance of the bipolar plate 1 during manufacturing can include incoming materials, manufacturing methods, operator operation, welding or bonding processes, and the working environment. After obtaining the leakage direction, operators can comprehensively judge the possible causes of the leakage based on its location, thereby improving the overall pass rate of the bipolar plate 1 production line. For example, if multiple leaking bipolar plates leak from the same location, it may be due to poor welding or bonding processes at that location. If the leaking locations of multiple leaking bipolar plates are different, it may be due to the incoming materials or the working environment causing the failure to seal the bipolar plate 1.

[0110] The following example illustrates the method for testing the sealing performance of bipolar plates:

[0111] In this case study, the bipolar plate sealing test device uses a leak detector in test unit 5. The device has two leak detectors (A and B), each testing three bipolar plate groups. Each test unit 4 has six ultrasonic probes. Please refer to [link to relevant documentation]. Figure 2 The detection method is as follows:

[0112] Leak detector A is connected to the test channels of the hydrogen chamber, cooling chamber, and air cavity of the first, second, and third groups of pressure plates 42 to test the air tightness of the first, second, and third groups of bipolar plates 1; Leak detector B is connected to the test channels of the hydrogen chamber, cooling chamber, and air cavity of the fourth, fifth, and sixth groups of pressure plates 42 to test the air tightness of the fourth, fifth, and sixth groups of bipolar plates 1.

[0113] Sequentially open the hydrogen chamber test line, cooling chamber test line, and cavity test line, and measure the sealing performance of the three cavities of bipolar plate 1. Introduce test gas at a certain pressure into the lines and maintain the pressure for a certain period. If the pressure drop value displayed by the leak detector is less than the required value, it indicates that the sealing performance of bipolar plate 1 is qualified. If the pressure drop value displayed by the leak detector is greater than the required value, it indicates that the sealing performance of bipolar plate 1 is unqualified.

[0114] In addition, each pressure plate 42 is surrounded by a set of ultrasonic probes 43. The isolation cover 9 separates each bipolar plate group and its ultrasonic probes 43, forming a sealed space to prevent interference between leak detections between groups and to more accurately determine the group with the leak. Furthermore, the strongest signal detected by a particular ultrasonic probe 43 around a leaking group can pinpoint the area of ​​leakage in that group of bipolar plates 1, providing support for improving poor welding or bonding seals of the bipolar plates 1.

[0115] For example, if the results of leak detectors A and B show that they are qualified, then the airtightness of bipolar plates 1 in groups 1-6 is qualified; if leak detector A shows that they are unqualified, then the data collected by ultrasonic probes 43 distributed around groups 1, 2, and 3 can be used to determine which bipolar plate group is leaking.

[0116] For example, if Group 1 is determined to be unqualified, then the bipolar plates 1 in Group 1 are divided into 6 groups, which can be equally divided or unequally divided. This process is repeated multiple times to further pinpoint the leaking bipolar plates until all unqualified bipolar plates 1 are identified. Furthermore, the leaking areas of bipolar plates 1 can be located. If a certain area experiences frequent leaks, it indicates that defects such as incomplete welds, burn-throughs, or weak adhesion are likely to occur in that area during the welding or bonding process of bipolar plates 1. This suggests the need to investigate whether there are any abnormalities in the welding or bonding process parameters, fixtures, or deformation of bipolar plates 1 in that area, providing support for improving the welding or bonding process.

[0117] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0118] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0119] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0120] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0121] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A bipolar plate sealing performance testing device, characterized in that, It includes an upper worktable, a lower worktable disposed below the upper worktable, multiple test units, at least one detection unit, and an isolation cover. The multiple test units are spaced apart on the lower worktable, and the upper worktable is operably pressed against the lower worktable to press the multiple test units together. The test unit includes: An upper pressure plate is provided on the upper worktable; A lower pressure plate is provided on the lower worktable. The upper pressure plate and the lower pressure plate can operably clamp multiple bipolar plates together. One end of the lower pressure plate is provided with multiple air inlets corresponding to the flow channels of the bipolar plates. Multiple auxiliary test boards are provided, each having multiple auxiliary flow channels corresponding to the flow channels of the bipolar plate. The multiple auxiliary test boards and the multiple bipolar plates are stacked alternately between the upper pressure plate and the lower pressure plate. The multiple air inlets are respectively connected to the multiple flow channels of the stacked bipolar plates and the multiple auxiliary flow channels of the auxiliary test boards to form multiple test channels. Multiple ultrasonic probes are disposed on the periphery of the lower pressure plate; The detection unit is connected to at least two test units and multiple test channels; the isolation cover is detachably mounted on the lower pressure plate and has multiple closed isolation cavities, with each test unit corresponding to one of the isolation cavities.

2. The bipolar plate sealing performance testing device according to claim 1, characterized in that, Sealing rings are provided between the upper pressure plate and the bipolar plate, between the lower pressure plate and the bipolar plate, and between the auxiliary test plate and the bipolar plate.

3. The bipolar plate sealing performance testing device according to claim 1, characterized in that, The testing unit also includes an elastic element, which is disposed between the lower pressure plate and the lower worktable in a compressed state.

4. The bipolar plate sealing performance testing device according to claim 1, characterized in that, Each of the test units includes at least four ultrasonic probes, which are distributed around the bipolar plate.

5. The bipolar plate sealing performance testing device according to claim 1, characterized in that, The test units are arranged in a matrix; The isolation cover includes a cover body and at least one transverse partition and at least one longitudinal partition disposed within the cover body. The transverse partition and the longitudinal partition are cross-connected to divide the inner cavity of the cover body into a plurality of isolation cavities.

6. The bipolar plate sealing performance testing device according to claim 1, characterized in that, Each of the test units has an air inlet connected to an air inlet pipe, and at least two of the air inlet pipes are connected to the same main air inlet pipe. A flow meter is installed on the air inlet pipe or the main air inlet pipe.

7. A method for testing the sealing performance of a bipolar plate, applied to the bipolar plate sealing performance testing device according to any one of claims 1-6, characterized in that, (1) The multiple sets of bipolar plates to be tested are respectively placed in the multiple test units of the bipolar plate sealing test device; (2) Test gas is continuously introduced into the test channel of each test unit to a set pressure, and the bipolar plate of the multiple test units connected to the detection unit is detected to see if leakage occurs. (3) Determine the bipolar plate group in which the leaking bipolar plate is located among the multiple test units connected to the detection unit based on the detection signal of the ultrasonic probe; (4) Divide the bipolar plate group containing the leaking bipolar plate into multiple bipolar plate sub-units, and place them into multiple test units respectively; (5) Repeat steps (2) to (4) until the leaking bipolar plate is identified.

8. The bipolar plate sealing performance testing method according to claim 7, characterized in that, In step (5), after determining the leaking bipolar plate, the bipolar plate sealing detection method further includes: determining the leakage location of the leaking bipolar plate based on the detection signal of the ultrasonic probe.

9. The bipolar plate sealing performance testing method according to claim 7, characterized in that, In step (2), the detection unit detects whether the bipolar plates of the multiple test units connected to the detection unit are leaking, specifically including: Test gas is continuously introduced into the test channel of each test unit. The flow rate of the test gas is obtained through the detection unit; Based on the obtained flow rate of the test gas, it is determined whether the bipolar plates of the multiple test units are leaking.

10. The bipolar plate sealing performance testing method according to claim 7, characterized in that, In step (2), the detection unit detects whether the bipolar plates of the multiple test units connected to the detection unit are leaking, specifically including: The test channel is a closed cavity; The air pressure value of the test channel is obtained through the detection unit; Based on the obtained air pressure value of the test channel, it is determined whether the bipolar plates of the multiple test units are leaking.

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