Leak detection device for metal bipolar plate of fuel cell

Abstract

The utility model discloses a leak detection device for a metal bipolar plate of a fuel cell. The leak detection device comprises a detection tool and a water tank, the detection tool comprises a transparent upper pressing plate and a transparent lower pressing plate, and the upper pressing plate and the lower pressing plate are used for pressing and clamping the bipolar plate for testing through sealing strips arranged on the surfaces of the two sides of the bipolar plate and sealing and isolating a hydrogen cavity, an oxygen cavity and a water cavity in the bipolar plate respectively. Three air inlets and three air outlets are formed in the upper pressing plate, and during testing, the three air inlets and the three air outlets are communicated with the hydrogen cavity, the oxygen cavity and the water cavity respectively; and the water tank is used for immersing a testing tool during testing, and observing whether bubbles overflow from the edges of the clamping surfaces of the upper pressing plate and the lower pressing plate and the positions of the bubbles when testing gas is introduced into any one gas inlet and other gas inlets and gas outlets are closed for pressure maintaining, so that the effect of quickly locking a leakage point is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cell polar plate sealing, in particular to a fuel cell metal bipolar plate leakage detection device. Background Art

[0002] After the fuel cell metal bipolar plate is sealed, it is necessary to test its airtightness. However, most of the current equipment for testing the airtightness of metal bipolar plates can only judge the quality of the airtightness, but cannot locate the specific leak location. In addition, metal bipolar plates are generally anti-corrosive by surface treatment on a stainless steel substrate, but after a long period of operation, the metal surface will still corrode. In severe cases, the stainless steel substrate will be corroded and leaks will occur. Therefore, accurately finding the location of the bipolar plate leak is crucial for corrosion mechanism analysis and design optimization. The specific location of the bipolar plate leak corresponds to different causes of the leak. Currently, only special equipment can detect the leak, and it requires vacuum, special gas conditions and a special detection method, and the testing cost is very high. Utility Model Content

[0003] The purpose of the utility model is to overcome the above-mentioned defects in the prior art and provide a fuel cell metal bipolar plate leak detection device.

[0004] To achieve the above purpose, the technical solution of the utility model is as follows:

[0005] The utility model provides a fuel cell metal bipolar plate leak detection device, comprising a detection fixture and a water tank;

[0006] The inspection fixture comprises a transparent upper pressing plate and a transparent lower pressing plate, wherein the upper pressing plate and the lower pressing plate are used to clamp the bipolar plate for testing through sealing strips provided on both sides of the bipolar plate, and to seal and isolate the hydrogen cavity, oxygen cavity and water cavity on the bipolar plate;

[0007] The upper pressure plate is provided with three air inlets and three air outlets. During the test, the three air inlets and the three air outlets are connected to the hydrogen chamber, the oxygen chamber and the water chamber respectively.

[0008] The water tank is used for the inspection tool during immersion testing, and when the test gas is introduced into any one of the air inlets and the other air inlets and outlets are closed to maintain pressure, observe whether there are bubbles overflowing from the edges of the clamping surfaces of the upper pressing plate and the lower pressing plate and the location of the bubbles.

[0009] Furthermore, a water inlet and a water outlet are provided on the upper pressure plate, and the water inlet and the water outlet are connected to face the hydrogen chamber or the oxygen chamber of the upper pressure plate when testing; wherein, when the hydrogen chamber or the oxygen chamber is tested, the water inlet and the water outlet are closed, and when the water chamber is tested, the test liquid is also introduced into the water inlet, and the water outlet is kept open, so as to observe whether there are bubbles overflowing from the hydrogen chamber or the oxygen chamber filled with the test liquid and the position of the bubbles through the upper pressure plate.

[0010] Furthermore, a hydrogen chamber inlet and a hydrogen chamber outlet connected to the hydrogen chamber, an oxygen chamber inlet and an oxygen chamber outlet connected to the oxygen chamber, and a water chamber inlet and a water chamber outlet connected to the water chamber are provided at both ends of the surface of the bipolar plate. The three air inlets are provided on one end of the upper pressure plate, and correspond to the positions of the hydrogen chamber inlet, the oxygen chamber inlet and the water chamber inlet respectively for communication. The three air outlets are provided on the other end of the upper pressure plate, and correspond to the positions of the hydrogen chamber outlet, the oxygen chamber outlet and the water chamber outlet respectively for communication. The water inlet and the water outlet are located in the middle of the upper pressure plate, and correspond to the position of the hydrogen chamber or the oxygen chamber facing the upper pressure plate during testing for communication.

[0011] Furthermore, the air inlet, the air outlet, the water inlet and the water outlet are respectively connected with a delivery pipe, and each of the delivery pipes is provided with a switch valve.

[0012] Furthermore, a first boss is provided on the bottom surface of the upper pressing plate, and the surface of the first boss is the clamping surface of the upper pressing plate. A second boss is provided on the top surface of the lower pressing plate, and the surface of the second boss is the clamping surface of the lower pressing plate.

[0013] Furthermore, the height of the first boss and the second boss is 2 to 3 times the thickness of the bipolar plate.

[0014] Furthermore, the upper pressing plate and the lower pressing plate are connected by a fastening structure to press the clamped bipolar plate, and the fastening structure is arranged between the bottom surface of the upper pressing plate and the top surface of the lower pressing plate outside the first boss and the second boss.

[0015] Furthermore, the fastening structure is arranged in plurality around the first boss and the second boss, and the fastening structure includes a through hole provided on the upper pressure plate, and a guide column provided on the lower pressure plate, and a screw hole is provided on the top surface of the guide column. When the bipolar plate is clamped, the guide column is fitted into the through hole, and the upper pressure plate and the lower pressure plate are connected by screwing a fastening bolt into the screw hole exposed from the top surface of the upper pressure plate into the through hole, and the bipolar plate is evenly pressed.

[0016] Furthermore, a positioning protrusion is provided on the corner of the table surface of the second boss, which is used to cooperate with a positioning hole provided on the corresponding corner of the bipolar plate.

[0017] Furthermore, the test fixture is placed flat in the water tank for testing, and the water level is above the clamping surface of the upper pressing plate and below the top surface of the upper pressing plate.

[0018] It can be seen from the above technical scheme that the utility model uses a test fixture including a transparent upper pressure plate and a transparent lower pressure plate to clamp the bipolar plate and immerse it in a water tank for testing. It can not only detect the airtight failure of the bipolar plate by observing whether there are bubbles overflowing from the edge of the clamping surface, but also accurately find the specific leakage position of the bipolar plate with sealing failure through the observed bubble position. In addition, when testing the water cavity, by passing the test liquid into the hydrogen cavity or oxygen cavity when the upper pressure plate is facing the surface, it is possible to observe whether there are bubbles overflowing and the bubble position in the hydrogen cavity or oxygen cavity filled with the test liquid through the transparent upper pressure plate, so as to judge the specific internal leakage position of the water cavity. Therefore, under normal circumstances, only by using test media such as compressed air and water, the effect of quickly locking the leakage point can be achieved. The utility model has the following advantages:

[0019] (1) By using transparent upper and lower pressure plates, the uniformity of compression of the sealing strips on the bipolar plates can be observed in real time, and the location of the leakage point when bubbles are generated in the water tank can be clearly observed.

[0020] (2) The fastening structure adopts the combination of a guide column with a screw hole and a through hole, and uses a fastening method of bolts and screw holes to connect the upper pressure plate and the lower pressure plate, so that the bipolar plates can be tightly pressed together, and the torque of the bolts can be controlled to achieve uniform force, so that the compression degree of the sealing strip at each point is similar.

[0021] (3) By designing the clamping surfaces of the upper pressure plate and the lower pressure plate as a raised step structure (a first boss and a second boss), when bubbles are generated in the water, the bosses can be discharged upward faster under the action of the tension of the water, making the bubbles easier to identify and quickly locate the leakage, saving time.

[0022] (4) By simultaneously arranging a water inlet and a water outlet on the upper pressure plate, when water (test liquid) is introduced into the water inlet, the gas in the hydrogen chamber or the oxygen chamber can be directly discharged from the water outlet, thereby optimizing the water inlet efficiency.

[0023] (5) The device is easy to operate and the testing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1The present invention is a schematic diagram of a fuel cell metal bipolar plate leak detection device according to a preferred embodiment of the present invention.

[0025] Figure 2 The figure is a schematic structural diagram of an upper pressing plate according to a preferred embodiment of the utility model.

[0026] Figure 3 The figure is a schematic structural diagram of a lower pressing plate according to a preferred embodiment of the utility model.

[0027] Figure 4 This is a schematic diagram of a lower pressure plate and a bipolar plate in a state ready to be matched according to a preferred embodiment of the utility model.

[0028] Figure 5 The figure is a schematic diagram of a top view of a checking fixture clamping a bipolar plate according to a preferred embodiment of the utility model. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the utility model belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0030] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings.

[0031] refer to Figure 1-Figure 5 The utility model discloses a fuel cell metal bipolar plate leak detection device, comprising a test fixture 2 and a water tank 1. The test fixture 2 is used to seal and clamp the fuel cell metal bipolar plate 6 to be tested, and to detect the air tightness of the bipolar plate 6; the water tank 1 is used in conjunction with the test fixture 2 that clamps the bipolar plate 6 to find and lock the sealing failure state of the bipolar plate 6, thereby realizing the detection of whether the bipolar plate 6 has leakage, and the sealing performance of the bipolar plate 6 can be evaluated through testing.

[0032] The inspection fixture 2 includes a transparent upper pressing plate 3 and a transparent lower pressing plate 4; the upper pressing plate 3 and the lower pressing plate 4 are used to press and clamp the bipolar plate 6 to be tested. An upper clamping surface is provided on the bottom surface of the upper pressing plate 3, and a lower clamping surface is provided on the top surface of the lower pressing plate 4; when clamping the bipolar plate 6, the bipolar plate 6 is placed on the lower clamping surface of the lower pressing plate 4, and the upper pressing plate 3 is placed flat on the bipolar plate 6, so that the upper clamping surface of the upper pressing plate 3 corresponds to the position of the bipolar plate 6 and the lower clamping surface below, and the bipolar plate 6 can be pressed and clamped by applying pressure.

[0033] The bipolar plate 6 is provided with a hydrogen cavity 64, an oxygen cavity and a water cavity. The hydrogen cavity 64 and the oxygen cavity are exposed on both sides of the bipolar plate 6, respectively, and the water cavity is located inside the bipolar plate 6 (i.e., between the two monopolar plates) and between the hydrogen cavity 64 and the oxygen cavity. Figure 4 and Figure 5 The test state is shown when one side surface of the bipolar plate 6 with the hydrogen cavity 64 faces the upper pressing plate 3, and the other side surface with the oxygen cavity faces the lower pressing plate 4. However, it can be understood that during the test, the one side surface of the bipolar plate 6 with the oxygen cavity can also face the upper pressing plate 3, and the other side surface with the hydrogen cavity 64 can face the lower pressing plate 4.

[0034] Sealing strips 69 are respectively provided on both side surfaces of the bipolar plate 6. When the bipolar plate 6 is set in a fuel cell, the sealing strips 69 seal and isolate the hydrogen cavity 64, the oxygen cavity and the water cavity on the bipolar plate 6 independently, so that the hydrogen cavity 64, the oxygen cavity and the water cavity cannot communicate with each other.

[0035] When the bipolar plate 6 is clamped, the upper pressing plate 3 and the lower pressing plate 4 compress the sealing strips 69 provided on the two side surfaces of the bipolar plate 6 to achieve the compression and clamping of the bipolar plate 6, so that the sealing performance of the bipolar plate 6 can be tested. In addition, since the upper pressing plate 3 and the sealing strip 69, and the lower pressing plate 4 and the sealing strip 69 are in sealed contact, the sealing strip 69 can be used to simulate the working conditions, and the hydrogen cavity 64, the oxygen cavity and the water cavity on the bipolar plate 6 can also be sealed and isolated independently. After the upper pressing plate 3 and the lower pressing plate 4 compress the bipolar plate 6 by the sealing strip 69, the upper clamping surface of the upper pressing plate 3 and the lower clamping surface of the lower pressing plate 4 become sealing surfaces, so that the hydrogen cavity 64, the oxygen cavity and the water cavity on the bipolar plate 6 are sealed and isolated from each other.

[0036] When performing air tightness testing, it is necessary to ventilate the hydrogen cavity 64, oxygen cavity or water cavity on the bipolar plate 6 to be tested for testing. Therefore, it is necessary to set a vent on the test fixture 2 that is connected to the hydrogen cavity 64, oxygen cavity and water cavity on the bipolar plate 6 under test.

[0037] Specifically, the upper pressing plate 3 is provided with three air inlets 31 and three air outlets 34. When the bipolar plate 6 is pressed and clamped between the upper pressing plate 3 and the lower pressing plate 4 to perform an air tightness test on the bipolar plate 6, the three air inlets 31 are respectively connected to the hydrogen cavity 64, the oxygen cavity and the water cavity, and at the same time, the three air outlets 34 are also respectively connected to the hydrogen cavity 64, the oxygen cavity and the water cavity. One air inlet 31 and one air outlet 34 connected to the same cavity (hydrogen cavity 64, oxygen cavity or water cavity) form a pair of air inlets 31 and air outlets 34.

[0038] When the test gas is introduced into any one of the gas inlets 31, the test gas will pass through the hydrogen cavity 64, oxygen cavity or water cavity connected to the any one of the gas inlets 31, and be discharged from the corresponding one of the gas outlets 34. When the corresponding one of the gas outlets 34 is closed and the test gas is continuously introduced, the test gas will fill the corresponding hydrogen cavity 64, oxygen cavity or water cavity until the predetermined test pressure is reached in the cavity.

[0039] The water tank 1 contains the test liquid, which is used to immerse the test fixture 2 during the test. When the test gas is introduced into any one of the air inlets 31 and the other air inlets 31 and air outlets 34 are closed to maintain the pressure, observe whether there are bubbles overflowing from the edges of the clamping surfaces of the upper pressing plate 3 and the lower pressing plate 4 and the bubble positions. For example, when testing the hydrogen cavity 64, firstly introduce the test gas into the air inlet 31 of a pair of air inlets 31 and air outlets 34 connected to the hydrogen cavity 64, and close the air outlet 34 in the pair, and maintain the pressure of the hydrogen cavity 64 after ventilation; and close the other two pairs of air inlets 31 and air outlets 34 connected to the oxygen cavity and the water cavity. Then, by visually observing the inspection fixture 2 immersed in the test liquid in the water tank 1, it can be checked whether there are bubbles overflowing at the edge of the clamping surface of the upper pressing plate 3 to the bipolar plate 6 and the edge of the clamping surface of the lower pressing plate 4 to the bipolar plate 6, and the transparent properties of the upper pressing plate 3 and the lower pressing plate 4 can be used to accurately determine the bubble position when bubbles occur. The generation of bubbles indicates that the seal of the bipolar plate 6 has failed, so the leakage point of the bipolar plate 6 can be accurately determined based on the overflow position of the bubbles. Therefore, when the airtightness of the metal bipolar plate 6 is tested after the initial sealing is completed, the specific leakage position can be locked, and feedback can be given to the previous process to perform corresponding process improvements and yield improvements. The metal bipolar plate 6 with failed sealing can also be tested for a second time to lock the specific leakage point for failure analysis.

[0040] In some embodiments, the upper platen 3 is further provided with a water inlet 36 and a water outlet 35. The water inlet 36 and the water outlet 35 are connected to the hydrogen cavity 64 or the oxygen cavity facing the upper platen 3 during the test.

[0041] refer to Figure 2 and Figure 5 ( Figure 5The structure is simplified in the drawing). A water inlet 36 and a water outlet 35 are provided on the top surface of the upper pressing plate 3, forming a pair of water inlet 36 and water outlet 35. In this embodiment, the water inlet 36 and the water outlet 35 are connected to the hydrogen cavity 64 facing the upper pressing plate 3 during the test, but are not connected to the oxygen cavity. That is, when the bipolar plate 6 is placed on the lower pressing plate 4, if the side surface of the bipolar plate 6 with the hydrogen cavity 64 is placed upward, when the upper pressing plate 3 is pressed against the sealing strip 69 on the side surface of the bipolar plate 6, the water inlet 36 and the water outlet 35 provided on the upper pressing plate 3 will be connected to the hydrogen cavity 64. Since the oxygen cavity is located on the lower side of the bipolar plate 6 in this state, the water inlet 36 and the water outlet 35 will not be connected to the oxygen cavity.

[0042] When the oxygen cavity faces the upper platen 3 during the test, the water inlet 36 and the water outlet 35 are connected to the oxygen cavity, but not to the hydrogen cavity 64. The following will be described by taking the side surface of the bipolar plate 6 with the hydrogen cavity 64 facing the upper platen 3 as an example. Please refer to the situation when the side surface of the bipolar plate 6 with the oxygen cavity faces the upper platen 3 for understanding.

[0043] In some embodiments, when the hydrogen chamber 64 or the oxygen chamber is tested, the water inlet 36 and the water outlet 35 need to be closed. The test gas is introduced into the inlet 31 of the pair of inlets 31 and outlets 34 connected to the hydrogen chamber 64 or the oxygen chamber, and the outlet 34 in the pair is closed. The hydrogen chamber 64 or the oxygen chamber after ventilation is pressurized, and the other two pairs of inlets 31 and outlets 34 not connected to the hydrogen chamber 64 or the oxygen chamber are closed.

[0044] In some embodiments, when the water cavity is tested, the test gas is introduced into the air inlet 31 of the pair of air inlets 31 and air outlets 34 connected to the water cavity, and the air outlet 34 in the pair is closed, the pressure of the ventilated water cavity is maintained, and the other two pairs of air inlets 31 and air outlets 34 connected to the hydrogen cavity 64 and the oxygen cavity are closed, and the test liquid is further introduced into the water inlet 36, and the water outlet 35 is kept open. In this embodiment, since the air inlet 31 and the air outlet 34 are connected to the hydrogen cavity 64, when the test liquid is introduced through the water inlet 36, the introduced test liquid will fill the hydrogen cavity 64. Therefore, through the transparent upper pressing plate 3, by observing whether there is a bubble overflow in the hydrogen cavity 64 filled with the test liquid and the bubble position, that is, by observing the bubble situation of the flow field of the hydrogen cavity 64, it can be judged whether there is a leak in the water cavity inside the bipolar plate 6 located below the hydrogen cavity 64, and the specific position of the leak.

[0045] In some embodiments, the surfaces of the bipolar plate 6 are provided with a hydrogen cavity inlet 62 and a hydrogen cavity outlet 65 connected to the hydrogen cavity 64, an oxygen cavity inlet 63 and an oxygen cavity outlet 66 connected to the oxygen cavity, and a water cavity inlet 61 and a water cavity outlet 67 connected to the water cavity, respectively. Figure 4 and Figure 5 As shown. The above-mentioned inlets and outlets penetrate the two side surfaces of the bipolar plate 6. The hydrogen cavity inlet 62 and the hydrogen cavity outlet 65 are respectively connected to the hydrogen cavity 64 located on the upper surface of the bipolar plate 6 through the hydrogen cavity flow channel provided on the upper surface of the bipolar plate 6, the oxygen cavity inlet 63 and the oxygen cavity outlet 66 are respectively connected to the oxygen cavity located on the lower surface of the bipolar plate 6 through the oxygen cavity flow channel provided on the lower surface of the bipolar plate 6, and the water cavity inlet 61 and the water cavity outlet 67 are respectively connected to the water cavity located inside the bipolar plate 6 through the water cavity flow channel provided inside the bipolar plate 6.

[0046] The sealing strips 69 are respectively arranged on the upper surface and the lower surface of the bipolar plate 6; the sealing strips 69 on the two side surfaces are respectively distributed continuously along the circumference of the bipolar plate 6, and are continuously distributed along the periphery of the above-mentioned inlets and outlets, and the hydrogen chamber inlet 62, the hydrogen chamber outlet 65, the oxygen chamber inlet 63, the oxygen chamber outlet 66, the water chamber inlet 61 and the water chamber outlet 67 are respectively separated into 6 test chambers. Among them, the hydrogen chamber flow channel and the oxygen chamber flow channel pass through the bottom of the corresponding sealing strip 69, and are respectively connected with the hydrogen chamber 64 and the oxygen chamber located in the middle of the two side surfaces of the bipolar plate 6. In this way, when the upper pressing plate 3 and the lower pressing plate 4 press the bipolar plate 6 by the sealing strip 69, the hydrogen chamber 64, the oxygen chamber and the water chamber are sealed by the upper pressing plate 3 and the lower pressing plate 4 as independent chambers, and the oxygen test chamber, the hydrogen test chamber and the water test chamber are respectively formed.

[0047] In some embodiments, the three air inlets 31 are correspondingly arranged at one end of the top surface of the upper pressing plate 3 ( Figure 1 The three gas outlets 34 are arranged at the other end of the top surface of the upper pressing plate 3 ( Figure 1 The water inlet 36 and the water outlet 35 are located on the middle of the upper pressing plate 3, and correspond to the position of the hydrogen chamber 64 facing the upper pressing plate 3 during the test, so as to be connected after the bipolar plate 6 is clamped.

[0048] Figure 5 The top view shows the bipolar plate 6 being clamped between the transparent upper pressing plate 3 and the lower pressing plate 4 .

[0049] By simultaneously arranging the water inlet 36 and the water outlet 35 on the upper pressure plate 3 , when the test liquid is introduced into the water inlet 36 , the gas in the hydrogen cavity 64 can be directly discharged from the water outlet 35 , thereby optimizing the water inlet efficiency.

[0050] In some embodiments, the air inlet 31, the air outlet 34, the water inlet 36 and the water outlet 35 are respectively connected to a delivery pipe 32. Figure 1 As shown. The delivery pipe 32 connected to the air inlet 31 is connected to the air supply device for inputting the test gas to the air inlet 31; the delivery pipe 32 connected to the water inlet 36 is connected to the water supply device for inputting the test liquid to the water inlet 36. The air outlet 34 can be connected to the atmosphere. The water outlet 35 can be connected to the recovery equipment.

[0051] In some embodiments, the test gas includes compressed air.

[0052] In some embodiments, the test liquid comprises water.

[0053] In some embodiments, each delivery pipe 32 is provided with a switch valve for independently controlling the opening and closing of each air inlet 31 , air outlet 34 , water inlet 36 and water outlet 35 .

[0054] refer to Figure 1-Figure 4 In some embodiments, a first boss 37 is provided on the bottom surface of the upper pressing plate 3, and the surface of the first boss 37 is the clamping surface (upper clamping surface) of the upper pressing plate 3. A second boss 41 is provided on the top surface of the lower pressing plate 4, and the surface of the second boss 41 is the clamping surface (lower clamping surface) of the lower pressing plate 4. By designing the clamping surfaces of the upper pressing plate 3 and the lower pressing plate 4 as a raised step structure (first boss 37 and second boss 41), when the boss is subjected to the tension of water, when bubbles are generated in the water of the water tank 1, the bubbles can be discharged upward faster, so that the bubbles can be more easily identified, so as to quickly lock the leakage position and save time.

[0055] In some embodiments, the top surface of the first boss 37 and the top surface of the second boss 41 include a flat surface.

[0056] In some embodiments, in the clamped state, the edge of the first boss 37 and the edge of the second boss 41 should at least be located outside the sealing strip 69 on the corresponding side to completely compact the sealing strip 69 .

[0057] In some embodiments, in the clamped state, the edge of the first boss 37 and the edge of the second boss 41 are aligned or substantially aligned with the edge of the bipolar plate 6 .

[0058] In some embodiments, the height of the first boss 37 and the second boss 41 is 2 to 3 times the thickness of the bipolar plate 6 .

[0059] refer to Figure 1-Figure 3 In some embodiments, the upper pressing plate 3 and the lower pressing plate 4 are connected by a fastening structure 33 , and the fastening structure 33 is used to press the clamped bipolar plate 6 .

[0060] In some embodiments, the fastening structure 33 is disposed between the bottom surface of the upper pressing plate 3 and the top surface of the lower pressing plate 4 outside the first boss 37 and the second boss 41 .

[0061] In some embodiments, a plurality of fastening structures 33 are evenly arranged around the first boss 37 and the second boss 41. The number of fastening structures 33 can be evenly arranged according to actual needs, so as to ensure the stability of the gauge 2.

[0062] In some embodiments, the fastening structure 33 includes a through hole with a fastening bolt 331 provided on the upper pressing plate 3, and a guide column 332 provided on the lower pressing plate 4. Among them, a plurality of guide columns 332 are evenly provided on the top surface of the lower pressing plate 4 around the second boss 41; a screw hole 333 is provided on the top surface of the guide column 332. A corresponding number of through holes are evenly provided on the top and bottom surfaces of the upper pressing plate 3 around the first boss 37; a fastening bolt 331 is provided on the top surface of the upper pressing plate 3, and the lower end of the fastening bolt 331 is located in the through hole. When clamping the bipolar plate 6, first place the bipolar plate 6 flat on the surface of the second boss 41 of the lower pressing plate 4, then align the upper pressing plate 3 with the lower pressing plate 4, and insert the through holes on the upper pressing plate 3 into the corresponding guide pillars 332, so that the upper pressing plate 3 is placed flat on the bipolar plate 6, and then, from the top surface of the upper pressing plate 3, screw the fastening bolts 331 into the screw holes 333 exposed on the top surfaces of the guide pillars 332 in the through holes and tighten them to achieve the connection between the upper pressing plate 3 and the lower pressing plate 4, and evenly press the bipolar plate 6 between the upper pressing plate 3 and the lower pressing plate 4.

[0063] By using the fastening bolts 331 to connect the upper pressure plate 3 and the lower pressure plate 4, the bipolar plate 6 can be tightly pressed together, and the torque of each fastening bolt 331 can be made equal by a torque wrench to achieve uniform force and make the compression degree of the sealing strip 69 at each point similar.

[0064] refer to Figure 4 In some embodiments, a positioning hole 68 is provided on the corner of the bipolar plate 6, and a positioning protrusion 42 is provided on the corresponding corner of the table surface of the second boss 41 of the lower pressing plate 4. When the bipolar plate 6 is placed on the lower pressing plate 4, the positioning hole 68 of the bipolar plate 6 is matched with the positioning protrusion 42 of the lower pressing plate 4 to achieve the positioning of the bipolar plate 6 and facilitate the removal of the bipolar plate 6 after the test.

[0065] refer to Figure 1In some embodiments, during testing, the gauge 2 is placed flat in the water tank 1, the surface of the bipolar plate 6 is parallel to the horizontal plane, and the water level 5 is above the clamping surface of the upper pressing plate 3 and below the top surface of the upper pressing plate 3. For example, when the gauge 2 is immersed in the water of the water tank 1 for testing, the water level 5 is made to reach half the height of the upper pressing plate 3, and the water level 5 is prevented from submerging the upper pressing plate 3 so that the upper pressing plate 3 can be directly observed.

[0066] In some embodiments, support feet 43 are provided on the bottom surface of the lower pressing plate 4. Figure 1 and Figure 3-Figure 4 shown.

[0067] In some embodiments, the upper pressing plate 3 and the lower pressing plate 4 are made of transparent glass. When the upper pressing plate 3 and the lower pressing plate 4 are made of transparent glass, when the upper and lower pressing plates 4 and the metal bipolar plate 6 in the middle are tightly pressed together, the uniformity of the compression of the sealing strip 69 on the bipolar plate 6 can be observed in real time to determine whether the sealing strip 69 is in a sealed compression state, and the position of the leakage point when bubbles are generated in the water tank 1 can be clearly observed.

[0068] Since water needs to be introduced into the hydrogen chamber 64 (or oxygen chamber) through the water inlet 36 when testing the water chamber, the hydrogen chamber 64 or the oxygen chamber is generally inflated and tested first (in no particular order) and then the water chamber is inflated and tested.

[0069] When testing the hydrogen chamber 64 and the oxygen chamber, the main focus is on external leakage points (bubbles overflowing from the edge of the clamping surface). When testing the water chamber, the main focus is on the welding condition, so more attention is paid to the appearance of bubbles in the middle hydrogen chamber 64 (or oxygen chamber). Of course, there will also be external leakage points in the water chamber. Therefore, different leakage points on the bipolar plate 6 product can be found accordingly.

[0070] like Figure 1 As shown, the method of locking the leak point by using the test fixture 2 is to immerse the test fixture 2 in water and ventilate the cavity to be tested. If there is a leak in the test cavity, it will be reflected in the form of bubbles in the water. According to the location where the bubbles are generated, the leak position can be quickly locked. If the bubble precipitation point is at the periphery of the test fixture 2, the cause of the leak is generally the failure of the sealing strip 69; if the bubble precipitation point is at the center of the test fixture 2 (the hydrogen cavity 64 or oxygen cavity into which water is passed), the cause of the leak is generally the failure of the active area weld.

[0071] In some embodiments, the steps of testing the hydrogen chamber 64, the oxygen chamber and the water chamber in sequence include:

[0072] 1. Close the switch valves on the water inlet 36 and the water outlet 35;

[0073] 2. Close the switch valve on the gas outlet 34 corresponding to the hydrogen chamber outlet 65, and only allow gas to enter the gas inlet 31 corresponding to the hydrogen chamber inlet 62, and maintain the pressure to test the hydrogen chamber 64;

[0074] 3. Immerse the inspection fixture 2 holding the bipolar plate 6 in the water of the water tank 1, and make the water level 5 reach a position about half the height of the upper pressing plate 3; observe whether there are bubbles in the water of the water tank 1, and the position of the bubbles when they are generated. Once bubbles are generated, the leakage point can be locked;

[0075] 4. After completing the test of the hydrogen chamber 64, open the switch valve on the gas outlet 34 corresponding to the hydrogen chamber outlet 65 to exhaust the hydrogen chamber 64;

[0076] 5. Next, close the switch valve on the gas outlet 34 corresponding to the oxygen chamber outlet 66, and only allow gas to enter the gas inlet 31 corresponding to the oxygen chamber inlet 63, and maintain the pressure to test the oxygen chamber;

[0077] 6. Observe whether there are bubbles in the water of tank 1 and the location of the bubbles when they are generated. Once bubbles are generated, the leakage point can be located;

[0078] 7. After completing the test of the oxygen chamber, open the switch valve on the gas outlet 34 corresponding to the oxygen chamber outlet 66 to exhaust the oxygen chamber;

[0079] 8. Then, open the switch valves on the water inlet 36 and the water outlet 35 to allow water to flow into the upper hydrogen chamber 64 until the water fills the entire chamber;

[0080] 9. Close the switch valve on the air outlet 34 corresponding to the water chamber outlet 67, and only let air in through the air inlet 31 corresponding to the water chamber inlet 61, and maintain the pressure to test the water chamber;

[0081] 10. Observe the bubbles in the flow field of the hydrogen cavity 64 to determine whether there is an internal leakage point in the water cavity and the specific leakage location (including observing whether there are bubbles in the water in the water tank 1 and the location of the bubbles when they are generated to determine whether there is an external leakage point in the water cavity);

[0082] 11. End the test.

[0083] In summary, the utility model uses a test fixture 2 including a transparent upper pressing plate 3 and a transparent lower pressing plate 4 to clamp the bipolar plate 6 and immerse it in a water tank 1 for testing. It can not only detect the airtight failure of the bipolar plate 6 by observing whether there are bubbles overflowing from the edge of the clamping surface, but also accurately find the specific leakage position of the bipolar plate 6 with sealing failure through the observed bubble position. In addition, when testing the water cavity, by passing the test liquid into the hydrogen cavity 64 or the oxygen cavity when the upper pressing plate 3 is facing, it is possible to observe whether there are bubbles overflowing and the bubble position in the hydrogen cavity 64 or the oxygen cavity filled with the test liquid through the transparent upper pressing plate 3, and judge the specific internal leakage position of the water cavity. Therefore, under normal conditions, only by using test media such as compressed air and water, the effect of quickly locking the leak point can be achieved. The device of the utility model is easy to operate, has a low testing cost, and is suitable for promotion.

[0084] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A fuel cell metal bipolar plate leak detection device, characterized in that: Includes inspection fixture and sink; The inspection fixture comprises a transparent upper pressing plate and a transparent lower pressing plate, wherein the upper pressing plate and the lower pressing plate are used to clamp the bipolar plate for testing through sealing strips provided on both sides of the bipolar plate, and to seal and isolate the hydrogen cavity, oxygen cavity and water cavity on the bipolar plate; The upper pressure plate is provided with three air inlets and three air outlets. During the test, the three air inlets and the three air outlets are connected to the hydrogen chamber, the oxygen chamber and the water chamber respectively. The water tank is used for the inspection tool during immersion testing, and when the test gas is introduced into any one of the air inlets and the other air inlets and outlets are closed to maintain pressure, observe whether there are bubbles overflowing from the edges of the clamping surfaces of the upper pressing plate and the lower pressing plate and the location of the bubbles.

2. The fuel cell metal bipolar plate leak detection device according to claim 1, characterized in that: The upper pressure plate is also provided with a water inlet and a water outlet, and the water inlet and the water outlet are connected to face the hydrogen cavity or the oxygen cavity of the upper pressure plate when testing; wherein, when the hydrogen cavity or the oxygen cavity is tested, the water inlet and the water outlet are closed, and when the water cavity is tested, the test liquid is also introduced into the water inlet, and the water outlet is kept open, so as to observe through the upper pressure plate whether there are bubbles overflowing from the hydrogen cavity or the oxygen cavity filled with the test liquid and the position of the bubbles.

3. The fuel cell metal bipolar plate leak detection device according to claim 2, characterized in that: A hydrogen chamber inlet and a hydrogen chamber outlet connected to the hydrogen chamber, an oxygen chamber inlet and an oxygen chamber outlet connected to the oxygen chamber, and a water chamber inlet and a water chamber outlet connected to the water chamber are provided at both ends of the surface of the bipolar plate. The three air inlets are provided on one end of the upper pressure plate, and correspond to the positions of the hydrogen chamber inlet, the oxygen chamber inlet and the water chamber inlet for communication, respectively. The three air outlets are provided on the other end of the upper pressure plate, and correspond to the positions of the hydrogen chamber outlet, the oxygen chamber outlet and the water chamber outlet for communication, respectively. The water inlet and the water outlet are located in the middle of the upper pressure plate, and correspond to the position of the hydrogen chamber or the oxygen chamber facing the upper pressure plate during testing for communication.

4. The fuel cell metal bipolar plate leak detection device according to claim 2, characterized in that: The air inlet, the air outlet, the water inlet and the water outlet are respectively connected with a delivery pipe, and each of the delivery pipes is provided with a switch valve.

5. The fuel cell metal bipolar plate leak detection device according to claim 1, characterized in that: A first boss is provided on the bottom surface of the upper pressing plate, and the surface of the first boss is the clamping surface of the upper pressing plate. A second boss is provided on the top surface of the lower pressing plate, and the surface of the second boss is the clamping surface of the lower pressing plate.

6. The fuel cell metal bipolar plate leak detection device according to claim 5, characterized in that: The height of the first boss and the second boss is 2 to 3 times the thickness of the bipolar plate.

7. The fuel cell metal bipolar plate leak detection device according to claim 5, characterized in that: The upper pressing plate and the lower pressing plate are connected by a fastening structure to press the clamped bipolar plate. The fastening structure is arranged between the bottom surface of the upper pressing plate and the top surface of the lower pressing plate outside the first boss and the second boss.

8. The fuel cell metal bipolar plate leak detection device according to claim 7, characterized in that: The fastening structure is arranged in plurality around the first boss and the second boss, and the fastening structure includes a through hole provided on the upper pressure plate, and a guide column provided on the lower pressure plate, and a screw hole is provided on the top surface of the guide column. When the bipolar plate is clamped, the guide column is matched in the through hole, and the upper pressure plate and the lower pressure plate are connected by screwing the fastening bolts into the screw holes exposed from the top surface of the upper pressure plate into the through holes, and the bipolar plate is evenly compressed.

9. The fuel cell metal bipolar plate leak detection device according to claim 5, characterized in that: A positioning protrusion is provided on the corner of the table surface of the second boss, which is used to cooperate with a positioning hole provided on the corresponding corner of the bipolar plate.

10. The fuel cell metal bipolar plate leak detection device according to claim 2, characterized in that: The test fixture is placed flat in the water tank for testing, and the water level is above the clamping surface of the upper pressing plate and below the top surface of the upper pressing plate.

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