Measuring Device and Measuring Method for Air Leakage of Membrane Electrode

Abstract

The present application provides a measuring device and a measuring method for the air leakage amount of a membrane electrode, belonging to the technical field of membrane electrode air leakage detection. The measuring device for the air leakage amount of a membrane electrode includes a leak detection template, a rectifier, an air pipe, and a gas flowmeter. The leak detection template has a leak detection cavity, an air inlet, and an air outlet that communicate with the leak detection cavity. The leak detection template is used to seal and fix the membrane electrode so that the membrane electrode divides the leak detection cavity into a first cavity and a second cavity. The first cavity communicates with the air inlet, and the second cavity communicates with the air outlet. The rectifier is used to rectify the gas. The air pipe includes a first air pipe and a second air pipe. The front end of the first air pipe is used for air intake, the rear end of the first air pipe communicates with the inlet of the rectifier, the front end of the second air pipe communicates with the outlet of the rectifier, and the rear end of the second air pipe is used to communicate with the air inlet. The gas flowmeter is installed in the second air pipe and is used to detect the gas flow in the second air pipe. Through this measuring device, the air leakage amount of the membrane electrode can be measured more accurately.

Description

Technical Field

[0001] This application relates to the technical field of membrane electrode air leakage detection. Specifically, it relates to a measuring device and a measuring method for the air leakage volume of a membrane electrode. Background Art

[0002] The membrane electrode assembly (MEA, Membrane Electrode Assemblies) is one of the most important components of a hydrogen fuel cell. The airtight performance of the MEA determines the performance and lifespan of the fuel cell stack. If there is air leakage in the MEA of the fuel cell stack, after long-term operation, the air leakage situation will gradually deteriorate, seriously affecting the performance of the fuel cell stack. Therefore, it is necessary to first detect the airtightness of the MEA and screen out the MEAs with unqualified air leakage situations to make the performance of the fuel cell stack more stable.

[0003] When a traditional gas mass flowmeter is used to detect the gas leakage volume of a membrane electrode, since this flowmeter measures the leakage volume using a capillary structure, by leading out one of the capillaries, sensing and detecting it, and then calculating the gas flow rate in the entire pipeline. This structure has poor detection accuracy and low reliability, and is not suitable for detecting the leakage of MEAs with tiny gas leakage volumes. Summary of the Invention

[0004] The purpose of this application is to provide a measuring device and a measuring method for the air leakage volume of a membrane electrode, which can measure the air leakage volume of the membrane electrode more accurately.

[0005] In a first aspect, this application provides a measuring device for the air leakage volume of a membrane electrode, including a leak detection template, a rectifier, an air pipe, and a gas flowmeter. The leak detection template has a leak detection chamber and an air inlet and an air outlet communicating with the leak detection chamber. The leak detection template is used to seal and fix the membrane electrode so that the membrane electrode divides the leak detection chamber into a first chamber and a second chamber. The first chamber communicates with the air inlet, and the second chamber communicates with the air outlet. The rectifier is used to rectify the gas. The air pipe includes a first air pipe and a second air pipe. The front end of the first air pipe is used for air intake, the rear end of the first air pipe communicates with the inlet of the rectifier, the front end of the second air pipe communicates with the outlet of the rectifier, and the rear end of the second air pipe is used to communicate with the air inlet. The gas flowmeter is installed in the second air pipe and is used to detect the gas flow rate in the second air pipe.

[0006] Since the gas flowmeter is arranged in the second air pipe, and since a rectifier is installed at the front end of the second air pipe, the gas can be rectified, which can make the gas flow rate distribution uniform at the position close to the pipe wall and the position close to the pipe center. The gas flowmeter can detect the gas flow rate of the gas with a relatively uniform distribution in the pipeline, and the measured value is more accurate.

[0007] In a possible implementation, the rectifier includes a rectifying tube and a plurality of rectifying fins for gas to pass through. The two ends of the rectifying tube are respectively connected to the rear end of the first gas pipe and the front end of the second gas pipe. The plurality of rectifying fins are arranged at intervals inside the rectifying tube, and the edge of each rectifying fin is connected to the inner wall of the rectifying tube.

[0008] The gas flows inside the rectifying tube, and the plurality of rectifying fins are arranged at intervals. After the gas is rectified by one of the rectifying fins, it mixes between two adjacent rectifying fins, and then continues to be rectified by the next rectifying fin, so that the gas flow can be made more uniform and the flow rate detection more accurate.

[0009] In a possible implementation, the plurality of rectifying fins include a first set of orifice plates and a second set of orifice plates. The second set of orifice plates is close to the gas flowmeter. The apertures of the plurality of holes in the first set of orifice plates gradually decrease from the outer periphery inward, and the apertures of the plurality of holes in the second set of orifice plates are the same.

[0010] When the gas flows in the pipeline, the gas flow rate at the position close to the axis of the pipeline is larger, and the gas flow rate at the position close to the pipe wall of the pipeline is smaller. Therefore, along the gas flow direction, the outer peripheral aperture of the orifice plate close to the intake position is larger and the inner aperture is smaller. The first set of orifice plates can first divide the large air flow close to the axis of the pipeline into more fine air flows, and the smaller the aperture, the greater the resistance to the air flow, which can prompt the air flow to pass through the large holes close to the orifice wall, thereby increasing the air flow at the orifice wall. Then, the second set of orifice plates rectifies the air flow uniformly, so that the gas flow rate at the position of the gas flowmeter is more uniform.

[0011] In a possible implementation, the plurality of rectifying fins further include a third set of orifice plates, and the third set of orifice plates is located between the first set of orifice plates and the second set of orifice plates. The first set of orifice plates is arranged with a plurality of first holes, a plurality of second holes and a plurality of third holes from the outer periphery inward, and the aperture of the first hole > the aperture of the second hole > the aperture of the third hole. The third set of orifice plates is arranged with a plurality of fourth holes and a plurality of fifth holes from the outer periphery inward, and the aperture of the fourth hole > the aperture of the fifth hole; a plurality of sixth holes are uniformly arranged on the second set of orifice plates.

[0012] The three sets of orifice plates are arranged in sequence to rectify the gas step by step, which can make the rectifying effect of the gas better and the detected gas flow rate more accurate.

[0013] In a possible implementation, the aperture of the second hole is the same as the aperture of the fifth hole. The apertures of the fourth hole, the first hole and the sixth hole are the same. For the air flow close to the pipe wall position, the apertures of the three sets of orifice plates are the same and are the same as the apertures of the orifice plates close to the gas flowmeter, making the rectification of the gas more uniform, so that the test of the air leakage amount is more accurate.

[0014] In a possible implementation, the mesh number of the multiple holes of the first group of hole plates is 100 - 300 meshes. Optionally, the mesh number of the holes in the area where the first hole is located is 100 meshes, the mesh number of the holes in the area where the second hole is located is 200 meshes, and the mesh number of the holes in the area where the third hole is located is 300 meshes. Thereby, the rectifying effect of the air flow is better.

[0015] In a possible implementation, it further includes a bypass valve. The two ends of the bypass valve are respectively connected to the first position of the first air pipe and the second position of the second air pipe. The first position is between the front end of the first air pipe and the rectifier, and the second position is between the gas flowmeter and the air inlet.

[0016] When first ventilating the first cavity, directly open the bypass valve and ventilate through the bypass valve, which can quickly fill the first cavity with the detection gas, thereby shortening the measurement time and improving the measurement efficiency.

[0017] In a possible implementation, it further includes a standard calibration leak head. The standard calibration leak head is arranged between the gas flowmeter and the air inlet and is used to cut off or conduct the air flow of the air inlet.

[0018] The gas flowmeter can be calibrated through the standard calibration leak head, and then the air leakage amount of the membrane electrode can be detected, which can make the detection more accurate.

[0019] In a possible implementation, the gas flowmeter is a thermal gas mass flowmeter.

[0020] For ordinary gas mass flow meters, usually multiple capillary tubes are arranged on the flow meter, and then the flow rate of a single capillary tube is detected separately by a sensor, and then multiplied by the number of capillary tubes to obtain the gas flow rate. However, the structures of multiple capillary tubes usually have differences, which will make the detection of the flow rate inaccurate. If the above-mentioned thermal gas mass flowmeter is adopted, the gas flow rate is determined by the temperature difference between the upper and lower source air flows, and the measurement of the flow rate is more accurate.

[0021] In a possible implementation, it further includes an exhaust pipe, and the exhaust pipe is connected to the exhaust port. If the detected gas is not a gas that can be directly discharged into the air, an exhaust pipe needs to be set to process the discharged gas.

[0022] Second aspect, the present application provides a method for measuring the air leakage of a membrane electrode, which is applicable to the above-mentioned measuring device. The measuring method includes the following steps: sealing and fixing the membrane electrode to the leak detection template, so that the membrane electrode divides the leak detection cavity into a first cavity and a second cavity. The first cavity is communicated with the air inlet, and the second cavity is communicated with the air outlet. Ventilate the front end of the ventilation pipe. After the gas enters the first trachea, it passes through the rectifier, enters the second trachea, and then enters the first cavity from the air inlet. At the same time, the gas flowmeter detects the flow rate of the second trachea until the measured value of the gas flowmeter no longer changes.

[0023] By using the above-mentioned measuring method to measure the air leakage of the membrane electrode through the measuring device, the detection of the air leakage of the membrane electrode can be made more accurate. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings, which also belong to the protection scope of the present application.

[0025] Figure 1 It is a schematic structural diagram of the measuring device for the air leakage of the membrane electrode provided by the embodiment of the present application;

[0026] Figure 2 It is a schematic structural diagram of the fixing structure of the membrane electrode provided by the embodiment of the present application;

[0027] Figure 3 It is a schematic structural diagram of the rectifier provided by the embodiment of the present application.

[0028] Reference numerals: 110 - leak detection template; 120 - ventilation pipe; 130 - rectifier; 140 - gas flowmeter; 150 - bypass valve; 160 - pressure reducing valve; 170 - exhaust pipe; 180 - standard calibration leak; 111 - upper mold; 112 - lower mold; 113 - upper sealing ring; 114 - lower sealing ring; 115 - driving device; 116 - leak detection cavity; 117 - air inlet; 118 - air outlet; 1161 - first cavity; 1162 - second cavity; 200 - membrane electrode; 210 - frame; 220 - working area; 121 - first trachea; 122 - second trachea; 131 - rectifying tube; 132 - rectifying sheet; 1321 - first group of hole sheets; 1322 - second group of hole sheets; 1333 - third group of hole sheets; 1334 - first hole; 1335 - second hole; 1336 - third hole; 1337 - fourth hole; 1338 - fifth hole; 1339 - sixth hole. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application.

[0030] Embodiment 1

[0031] Figure 1 It is a schematic structural diagram of a measuring device for the air leakage amount of a membrane electrode provided in an embodiment of this application. Please refer to Figure 1 , in the embodiment of this application, the measuring device for the air leakage amount of the membrane electrode includes a leak detection template 110, an air pipe 120, a rectifier 130, a gas flowmeter 140, a bypass valve 150, a pressure reducing valve 160, and an exhaust pipe 170.

[0032] Figure 2 It is a schematic fixed structure diagram of the membrane electrode 200. Please refer to Figure 1 and Figure 2 , the leak detection template 110 is mainly used to fix the membrane electrode 200, and then make the gas pass through the fixed membrane electrode 200, so as to measure the air leakage condition of the membrane electrode 200.

[0033] In the embodiment of this application, the leak detection template 110 includes an upper mold 111, a lower mold 112, an upper sealing ring 113, a lower sealing ring 114, and a driving device 115. The upper sealing ring 113 is arranged on one side of the upper mold 111 close to the lower mold 112, the lower sealing ring 114 is arranged on one side of the lower mold 112 close to the upper mold 111, and the driving device 115 is drivingly connected to the upper mold 111. The driving device 115 drives the upper mold 111 to move downward (wherein, the type of the driving device 115 is not limited, and any structure that can drive the upper mold 111 to move up and down is within the protection scope of this application), so that the upper mold 111 and the lower mold 112 are closed. After closing, the upper sealing ring 113 and the lower sealing ring 114 are in sealing contact, and a leak detection cavity 116 is formed between the upper mold 111 and the lower mold 112.

[0034] Furthermore, the leak detection template 110 has an air inlet 117 and an air outlet 118 communicated with the leak detection cavity 116. The leak detection template 110 is used to seal and fix the membrane electrode 200 so that the membrane electrode 200 divides the leak detection cavity 116 into a first cavity 1161 and a second cavity 1162. The first cavity 1161 is communicated with the air inlet 117, and the second cavity 1162 is communicated with the air outlet 118.

[0035] When fixing the membrane electrode 200, place the frame 210 of the membrane electrode 200 on the lower sealing ring 114, and then drive the upper mold 111 to move downward through the driving device 115, so that the upper sealing ring 113 contacts the frame 210 and closes the mold, thereby fixing the frame 210 of the membrane electrode 200 between the upper sealing ring 113 and the lower sealing ring 114, preventing air leakage at the frame 210 of the membrane electrode 200. Then, when measuring the air leakage of the membrane electrode 200, the air leakage location is the working area 220 of the membrane electrode 200 (where the working area 220 refers to the catalyst area and the diffusion layer area of the membrane electrode 200), which can make the measurement of the air leakage of the membrane electrode 200 more accurate. After fixing the membrane electrode 200, a first cavity 1161 is formed between the membrane electrode 200 and the upper mold 111, and a second cavity 1162 is formed between the membrane electrode 200 and the lower mold 112. The first cavity 1161 is communicated with the air inlet 117, and the second cavity 1162 is communicated with the exhaust port 118.

[0036] Optionally, use a cylinder as the driving device 115. When the upper mold 111 and the lower mold 112 are driven to close the mold by the cylinder, a gas buffer tank is also configured for the cylinder to avoid fluctuations in the detected flow rate during the mold closing process.

[0037] Furthermore, a visual inspection mechanism is provided on the leak detection template 110, which can improve the alignment accuracy between the upper mold 111 and the lower mold 112 through mark point alignment, and can also detect the parallelism and flatness between the upper mold 111 and the lower mold 112 through the depth of field, thereby improving the airtightness and detection accuracy of the device.

[0038] The ventilation pipe 120 includes a first air pipe 121 and a second air pipe 122. The front end of the first air pipe 121 is for air intake (connected to the air source), the rear end of the first air pipe 121 is communicated with the inlet of the rectifier 130, the front end of the second air pipe 122 is communicated with the outlet of the rectifier 130, and the rear end of the second air pipe 122 is for communicating with the air inlet 117.

[0039] After installing the rectifier 130, the gas can be rectified by the rectifier 130, and then passes through the gas flowmeter 140. The use of the rectifier 130 can make the gas flow more uniformly when passing through the gas flowmeter 140, and the measured value of the gas flowmeter 140 is more accurate.

[0040] Figure 3 For the structural schematic diagram of the rectifier 130. Please refer to Figure 3 , the rectifier 130 includes a rectifying tube 131 and a plurality of rectifying fins 132 for the gas to pass through (where, Figure 3The dashed line part in A is the rectifying fin 132 installed in the rectifying tube 131). Both ends of the rectifying tube 131 are respectively connected to the rear end of the first air pipe 121 and the front end of the second air pipe 122. A plurality of rectifying fins 132 are arranged at intervals in the rectifying tube 131, and the edge of each rectifying fin 132 is connected to the inner wall of the rectifying tube 131.

[0041] The thickness of the rectifying fin 132 is about 1 mm, and the distance between two adjacent rectifying fins 132 is about 5 mm. The material of the rectifying fin 132 can be 316 stainless steel or other anti-corrosion materials. A plurality of ventilation holes are provided on the rectifying fin 132, which can allow gas to pass through the ventilation holes and be rectified. The mesh number of the ventilation holes can be 100 - 300 meshes. A plurality of rectifying fins 132 are arranged at intervals. After the gas is rectified by the rectifying fin 132 close to the first air pipe 121, it is mixed between two adjacent rectifying fins 132, and then rectified by the next rectifying fin 132 arranged at intervals, so that the flow of the gas can be made more uniform and the flow rate detection can be more accurate.

[0042] Furthermore, the plurality of rectifying fins 132 include a first group of orifice plates 1321 (such as Figure 3 B) and a second group of orifice plates 1322 (such as Figure 3 D), and the second group of orifice plates 1322 are close to the gas flowmeter 140. The apertures of the plurality of holes of the first group of orifice plates 1321 gradually decrease from the outer periphery inward, and the apertures of the plurality of holes of the second group of orifice plates 1322 are the same.

[0043] The reason for setting the above structure is that when the gas flows in the pipeline, the gas flow rate at the position close to the axis of the pipeline is larger, and the gas flow rate at the position close to the pipe wall is smaller. Therefore, along the gas flow direction, the outer peripheral aperture of the orifice plate (the first group of orifice plates 1321) close to the intake position is larger, and the inner aperture is smaller, which can first divide the large air flow at the position close to the axis of the pipeline into more fine air flows; then the air flow is uniformly rectified by the orifice plate (the second group of orifice plates 1322) close to the outlet position, so that the flow velocity of the gas at the position of the gas flowmeter 140 is more uniform.

[0044] It should be noted that the apertures of the plurality of holes of the first group of orifice plates 1321 gradually decrease from the outer periphery inward, which can mean that the aperture of the hole decreases one by one from the outer periphery to the inner circle, or it can mean that part of the aperture of the hole decreases from the outer periphery to the inner circle and part does not change. Optionally, the shape of the hole is a hexagonal honeycomb shape, which can make the rectifying effect of the rectifier 130 better.

[0045] Optionally, the plurality of rectifying fins 132 further include a third group of orifice plates 1333 (such as Figure 3C), the third set of orifice plates 1333 is located between the first set of orifice plates 1321 and the second set of orifice plates 1322. The first set of orifice plates 1321 is provided with a plurality of first holes 1334, a plurality of second holes 1335 and a plurality of third holes 1336 arranged inward along the outer periphery. The aperture of the first holes 1334 > the aperture of the second holes 1335 > the aperture of the third holes 1336 (wherein, the area of the first holes 1334 is in the outer peripheral area of the first set of orifice plates 1321, the area of the second holes 1335 is in the middle area of the first set of orifice plates 1321, and the area of the third holes 1336 is in the inner ring area of the first set of orifice plates 1321). The third set of orifice plates 1333 is provided with a plurality of fourth holes 1337 and a plurality of fifth holes 1338 arranged inward along the outer periphery. The aperture of the fourth holes 1337 > the aperture of the fifth holes 1338 (wherein, the area of the fourth holes 1337 is in the outer peripheral area of the second set of orifice plates 1322, and the area of the fifth holes 1338 is in the inner ring area of the second set of orifice plates 1322); A plurality of sixth holes 1339 are evenly arranged on the second set of orifice plates 1322 (wherein, the area of the sixth holes 1339 is in the entire area of the third set of orifice plates 1333). The rectification effect of the rectifier 130 can be made better.

[0046] Further, the aperture of the second holes 1335 is the same as the aperture of the fifth holes 1338. The aperture of the fourth holes 1337, the aperture of the first holes 1334 and the aperture of the sixth holes 1339 are the same. The air flow is gradually rectified. The rectification intensity of the air flow in the center of the pipe is relatively high, and the rectification intensity of the air flow near the pipe wall is relatively small. The gas can be finally rectified into a flow beam consistent with the sixth holes 1339, and the rectification effect of the gas is better.

[0047] In the embodiment of the present application, the mesh number of the holes in the area where the first holes 1334 are located is 100 meshes, the mesh number of the holes in the area where the second holes 1335 are located is 200 meshes, and the mesh number of the holes in the area where the third holes 1336 are located is 300 meshes. Thus, the rectification effect of the air flow is better. In other embodiments, it may also be that the mesh number of the holes in the area where the first holes 1334 are located is 100 meshes, the mesh number of the holes in the area where the second holes 1335 are located is 150 meshes, and the mesh number of the holes in the area where the third holes 1336 are located is 200 meshes; or the mesh number of the holes in the area where the first holes 1334 are located is 200 meshes, the mesh number of the holes in the area where the second holes 1335 are located is 250 meshes, and the mesh number of the holes in the area where the third holes 1336 are located is 300 meshes; or the mesh number of the holes in the area where the first holes 1334 are located is 50 meshes, the mesh number of the holes in the area where the second holes 1335 are located is 200 meshes, and the mesh number of the holes in the area where the third holes 1336 are located is 400 meshes. The present application does not make a limitation. As long as the aperture of the outer periphery is large, the aperture of the inner ring is small, and the orifice plate structure that can ensure the flow of gas and perform rectification is within the protection scope of the present application.

[0048] It should be noted that the number of the first group of orifice plates 1321 is not limited and can be 1 - 5; the number of the third group of orifice plates 1333 is not limited and can be 1 - 5; the number of the second group of orifice plates 1322 is not limited and can be 1 - 5.

[0049] In the embodiment of the present application, the gas flowmeter 140 is installed on the inner wall of the second air pipe 122 and is used to detect the gas flow in the second air pipe 122. The gas flow in the second air pipe 122 is detected by the gas flowmeter 140 to obtain the air leakage amount of the membrane electrode 200.

[0050] Optionally, the gas flowmeter 140 is a thermal gas mass flowmeter. For an ordinary gas mass flowmeter, usually multiple capillary tubes are provided on the flowmeter, and then the flow of one capillary tube is detected separately by a sensor, and then multiplied by the number of capillary tubes to obtain the gas flow. However, the structures of multiple capillary tubes usually have differences, which will make the detection of the flow inaccurate. If a thermal gas mass flowmeter is used, the gas flow is determined by the temperature difference between the upper and lower source airflows, and the measurement of the flow is more accurate.

[0051] Optionally, the thermal gas mass flowmeter is an instrument that measures the gas flow using the thermal diffusion principle. The sensor includes an upper source temperature measuring element, a heating element, and a lower source temperature measuring element. The upper source temperature measuring element and the lower source temperature measuring element are symmetrically arranged on both sides of the heating element. If the gas flow in the ventilation pipe 120 is 0, the temperature difference measured by the upper source temperature measuring element and the lower source temperature measuring element is 0; if the gas flow is not 0, the temperature difference measured by the upper source temperature measuring element and the lower source temperature measuring element is ΔT. According to the heating power P of the heating element and the above temperature difference value ΔT, the gas flow is calculated.

[0052] The flowmeter is arranged on the inner wall of the ventilation pipe 120. The overall chip size is about 5 mm in diameter, and the pipeline flow data can be displayed in real time. The flowmeter is built - in with a 16 - bit differential AD, and the sampling frequency is 2KHz, which can ensure that the flow measurement range is 0.05 - 2.0 SCCM, and the measurement accuracy is 0.002 SCCM. The thermal gas mass flowmeter is directly arranged on the inner wall of the pipe, with low differential pressure control and more accurate measurement results.

[0053] Furthermore, the thermal gas mass flowmeter is a uf micro - flow thermal - sensing sensor. The sensor chip of the sensor is installed on the inner wall of the second air pipe 122, and the display control unit is externally connected so as to conveniently observe the gas flow in the second air pipe 122.

[0054] In the embodiments of the present application, the bypass valve 150 is installed as follows: both ends of the bypass valve 150 are respectively connected to the first position of the first air pipe 121 and the second position of the second air pipe 122. The first position is between the front end of the first air pipe 121 and the rectifier 130, and the second position is between the gas flow meter 140 and the air inlet 117.

[0055] When starting to ventilate the leak detection chamber 116, if the gas is passed through the rectifier 130 and the gas flow meter 140 by using the ventilation pipe 120 and then enters the leak detection chamber 116 from the air inlet 117, the gas filling speed is slow, seriously affecting the measurement speed. Therefore, a bypass valve 150 is provided. First, ventilate at the bypass valve 150. When the pressure in the first cavity 1161 reaches the detection pressure (pressure range 0.01 - 0.5 MPa), then close the bypass valve 150, and detect the air leakage amount of the membrane electrode 200 through the rectifier 130 and the gas flow meter 140.

[0056] In the embodiments of the present application, the standard calibration leak head 180 is installed as follows: the standard calibration leak head 180 is arranged between the gas flow meter 140 and the air inlet 117 and is used to cut off or conduct the air flow of the air inlet 117.

[0057] If the standard calibration leak head 180 (the standard calibration leak head 180 has a standard air leakage amount) is opened and the air flow of the air inlet 117 is cut off, the flow test of the gas flow meter 140 can be verified through the standard calibration leak head 180, and the gas flow meter 140 can be adjusted and calibrated. Then, close the standard calibration leak head 180 and measure the air leakage amount of the membrane electrode 200 through the gas flow meter 140, and the measured value is more accurate.

[0058] Optionally, the connection between the standard calibration leak head 180 and the second air pipe 122 of the ventilation pipe 120 can be realized through a three-way valve to cut off or conduct the air flow of the air inlet 117.

[0059] In the embodiments of the present application, if the detected gas source is nitrogen, oxygen, etc., the gas can be directly discharged into the air through the exhaust port 118 of the second cavity 1162. If the detected gas source is an inert gas, hydrogen, etc., it is processed and discharged through the exhaust pipe 170. The exhaust pipe 170 is communicated with the exhaust port 118.

[0060] In the embodiments of the present application, in order to adjust the gas flow in the ventilation pipe 120, a pressure reducing valve 160 can also be provided at the front end of the ventilation pipe 120. The gas source enters the ventilation pipe 120 after passing through the pressure reducing valve 160 to adjust the air flow size in the ventilation pipe 120 and improve the measurement efficiency.

[0061] The above-mentioned measuring device for the air leakage of the membrane electrode can measure the air leakage of the membrane electrode 200.

[0062] Its measuring method includes the following steps:

[0063] (1). Seal and fix the membrane electrode 200 on the leak detection template 110, so that the membrane electrode 200 divides the leak detection cavity 116 into a first cavity 1161 and a second cavity 1162. The first cavity 1161 is communicated with the air inlet 117, and the second cavity 1162 is communicated with the air outlet 118.

[0064] Optionally, place the frame 210 of the membrane electrode 200 on the lower sealing ring 114 (with the anode side of the membrane electrode 200 facing down and the cathode side of the membrane electrode 200 facing up), and then drive the upper mold 111 to move downward through the driving device 115, so that the upper sealing ring 113 contacts and closes the mold with the other side of the frame 210, thereby fixing the frame 210 of the membrane electrode 200 between the upper sealing ring 113 and the lower sealing ring 114, so that there is no air leakage at the frame 210 of the membrane electrode 200. After the membrane electrode 200 is fixed, a first cavity 1161 is formed between the membrane electrode 200 and the upper mold 111, and a second cavity 1162 is formed between the membrane electrode 200 and the lower mold 112. The first cavity 1161 is communicated with the air inlet 117, and the second cavity 1162 is communicated with the air outlet 118.

[0065] (2). Open the standard calibration leak head 180, connect the standard calibration leak head 180 to the detection pipeline. The air leakage value of the standard calibration leak head 180 is fixed. Close the air inlet valve of the leak detection template 110, ventilate the ventilation pipe 120, and let the gas pass through the rectifier 130 and the gas flowmeter 140 (for example: thermal gas mass flowmeter), and then empty through the standard calibration leak head 180. Check whether the flow rate displayed by the thermal gas mass flowmeter matches the preset value of the standard calibration leak head 180. If the error range is within 2%, it is considered that the calibration is successful. Otherwise, adjust the relevant parameters of the thermal gas mass flowmeter until the matching requirement is met.

[0066] (3). Open the bypass valve 150, ventilate the front end of the first air pipe 121, and make the gas enter the first cavity 1161 of the leak detection cavity 116 from the air inlet 117 after passing through the bypass valve 150, so that the pressure of the first cavity 1161 can quickly reach the detection pressure (the pressure range is 0.01 - 0.5 MPa).

[0067] (4). Then close the bypass valve 150, and make the gas pass through the rectifier 130 and the gas flowmeter 140 (for example: thermal gas mass flowmeter) until the measured value of the gas flowmeter 140 no longer changes. If this value is 0, the membrane electrode 200 is airtight; if this value is not 0, the displayed value is the air leakage of the membrane electrode 200.

[0068] In this application, the measurement time of the single-piece membrane electrode 200 is about 30S, and the measurement accuracy can reach 0.002 SCCM. After the measurement of the single-piece membrane electrode 200 is completed, the intake air source valve is closed, the upper die 111 and the lower die 112 of the leak detection template 110 are opened, the measured membrane electrode 200 is taken out, and a new membrane electrode 200 to be measured is replaced, thus completing a measurement process.

[0069] In this application, to ensure the accuracy and stability of the measurement: a gas buffer tank can be added at the air source. After the air source passes through the buffer tank, it enters the ventilation pipe 120 to ensure the stable gas pressure in the ventilation pipe 120 (the first air pipe 121 and the second air pipe 122), and to avoid mutual interference between workstations and cause fluctuations in the detection flow rate.

[0070] In the embodiment of this application, to improve the measurement efficiency of the entire device, a dual-station or multi-station transformation can also be carried out. One gas flowmeter 140 can be connected to 2-4 detection templates, and peak-shift detection can be performed to improve the detection rhythm and detection efficiency.

[0071] For example: the rear end of the second air pipe 122 is connected to the air inlets 117 of multiple leak detection templates 110. When one leak detection template 110 measures the air leakage of one membrane electrode 200, the other leak detection templates 110 install other membrane electrodes 200, thereby improving the measurement efficiency.

[0072] The above description is only a part of the embodiments of this application and is not intended to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A measuring device for the air leakage volume of a membrane electrode, characterized in that, Comprising: A leak detection template, which has a leak detection cavity, an air inlet and an air outlet communicating with the leak detection cavity. The leak detection template is used to seal and fix the membrane electrode so that the membrane electrode divides the leak detection cavity into a first cavity and a second cavity. The first cavity communicates with the air inlet, and the second cavity communicates with the air outlet; A rectifier, which is used to rectify the gas; An air pipe, which includes a first air pipe and a second air pipe. The front end of the first air pipe is used for air intake, the rear end of the first air pipe is communicated with the inlet of the rectifier, the front end of the second air pipe is communicated with the outlet of the rectifier, and the rear end of the second air pipe is used to communicate with the air inlet. The rectifier includes a rectifying tube and a plurality of rectifying sheets for the gas to pass through. The two ends of the rectifying tube are respectively connected to the rear end of the first air pipe and the front end of the second air pipe. A plurality of rectifying sheets are arranged at intervals in the rectifying tube, and the edge of each rectifying sheet is connected to the inner wall of the rectifying tube. The plurality of rectifying sheets include a first group of hole sheets and a second group of hole sheets. The second group of hole sheets is close to the gas flowmeter. The apertures of the plurality of holes in the first group of hole sheets gradually decrease from the outer periphery to the inside, and the apertures of the plurality of holes in the second group of hole sheets are the same; A gas flowmeter, which is installed in the second air pipe and is used to detect the gas flow in the second air pipe; The number of meshes of the plurality of holes in the first group of hole sheets is 100 - 300 meshes; the gas flowmeter is a thermal gas mass flowmeter.

2. The measuring device according to claim 1, characterized in that, The plurality of rectifying sheets further include a third group of hole sheets, and the third group of hole sheets is located between the first group of hole sheets and the second group of hole sheets; The first group of hole sheets is arranged with a plurality of first holes, a plurality of second holes and a plurality of third holes from the outer periphery to the inside, and the aperture of the first hole > the aperture of the second hole > the aperture of the third hole; The third group of hole sheets is arranged with a plurality of fourth holes and a plurality of fifth holes from the outer periphery to the inside, and the aperture of the fourth hole > the aperture of the fifth hole; The second group of hole sheets is evenly arranged with a plurality of sixth holes.

3. The measuring device according to claim 2, characterized in that, The aperture of the second hole is the same as the aperture of the fifth hole; the aperture of the fourth hole, the aperture of the first hole and the aperture of the sixth hole are the same.

4. The measuring device according to any one of claims 1-3, characterized in that, It further includes a bypass valve, and the two ends of the bypass valve are respectively communicated with a first position of the first air pipe and a second position of the second air pipe. The first position is between the front end of the first air pipe and the rectifier, and the second position is between the gas flowmeter and the air inlet.

5. The measuring device according to any one of claims 1 to 3, characterized in that, It further includes a standard calibration leak head, which is arranged between the gas flowmeter and the air inlet and is used to cut off or conduct the air flow of the air inlet.

6. A method for measuring the air leakage volume of a membrane electrode, characterized in that, Applicable to the measuring device according to any one of claims 1 - 5, the measuring method includes the following steps: Seal and fix the membrane electrode on the leak detection template so that the membrane electrode divides the leak detection cavity into the first cavity and the second cavity. The first cavity communicates with the air inlet, and the second cavity communicates with the air outlet; Ventilate the front end of the vent pipe. After the gas enters the first trachea, it passes through the rectifier, enters the second trachea, and then enters the first cavity from the air inlet. At the same time, the gas flowmeter detects the flow rate of the second trachea until the measured value of the gas flowmeter no longer changes.

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