Helium detection device of membrane electrode and detection method of membrane electrode string leakage point

Abstract

The invention discloses a helium detection device of a membrane electrode and a detection method of a membrane electrode string leakage point, and belongs to the technical field of PEM water electrolysis hydrogen production. The helium detection device comprises a helium source, a membrane electrode to be detected, a porous material, a vacuum adsorption assembly, a vacuum pump and a helium mass spectrometer. The vacuum adsorption assembly adopts a cavity design, a plurality of adsorption holes are formed in the upper surface of the vacuum adsorption assembly, the porous material is placed on the upper surface of the vacuum adsorption assembly, a membrane electrode to be detected is placed on the porous material, and air in the cavity of the vacuum adsorption assembly is pumped out by a vacuum pump to form negative pressure; spraying a proper amount of helium to the surface of the membrane electrode to be detected on the porous material by using a helium source; and performing mass spectrum detection on the gas extracted by the vacuum pump by using a helium mass spectrum analyzer so as to analyze the series leakage point of the membrane electrode to be detected. The method is easy to operate and short in testing time, and nondestructive testing of the membrane electrode can be achieved. The detection precision is high, the reliability is strong, and the membrane electrode string leakage point can be qualitatively and quantitatively detected.

Description

Technical Field

[0001] The present invention belongs to the technical field of PEM electrolytic water hydrogen production, and particularly relates to a helium leak detection device for a membrane electrode, and also relates to a detection method for leak points in a membrane electrode string. Background Art

[0002] PEM (Proton Exchange Membrane) electrolytic water hydrogen production is an efficient and environmentally friendly hydrogen production method that uses a proton exchange membrane electrolytic cell to decompose water into hydrogen and oxygen; it has the characteristics of high efficiency and energy saving, quick start-up, high hydrogen purity, and environmental friendliness.

[0003] The PEM electrolytic water membrane electrode is the core component of the PEM electrolytic cell, which is composed of a proton exchange membrane, a catalyst layer, and a gas diffusion layer, and is responsible for the generation of hydrogen and oxygen in the water electrolysis reaction.

[0004] Gas cross-leakage in the PEM electrolytic water membrane electrode refers to the phenomenon that hydrogen and oxygen cross-permeate through the proton exchange membrane. The main reasons include: micropores, cracks, or mechanical damage may occur in the proton exchange membrane during production or use, resulting in gas permeation. Uneven pressure distribution during membrane electrode transfer may cause local deformation or damage of the membrane electrode, resulting in gas cross-leakage. It is difficult to distinguish from the appearance of the membrane electrode with the naked eye and requires the aid of a special detection device. Gas cross-leakage will reduce the hydrogen purity, increase safety hazards (such as forming an explosive mixture gas), and reduce the efficiency of the electrolytic cell.

[0005] The traditional method for detecting whether there is cross-leakage in the membrane electrode is to install it in the electrolytic cell and judge by testing its long-term voltage drop. The assembly process is cumbersome, the testing time is long, and the high voltage during assembly may damage the membrane electrode. Summary of the Invention

[0006] The purpose of the present invention is to overcome at least one deficiency of the prior art and provide a helium leak detection device for a membrane electrode and a detection method for leak points in a membrane electrode string.

[0007] The technical solution adopted by the present application is as follows:

[0008] A helium leak detection device for a membrane electrode, the helium leak detection device includes:

[0009] A helium gas source, a membrane electrode to be tested, a porous material, a vacuum adsorption assembly, a vacuum pump, and a helium mass spectrometer;

[0010] Among them, the vacuum adsorption assembly adopts a cavity design, and a plurality of adsorption holes are opened on its upper surface, and the adsorption holes are communicated with the cavity inside the vacuum adsorption assembly; the vacuum adsorption assembly is connected to one end of the vacuum pump, and the other end of the vacuum pump is connected to the helium mass spectrometer;

[0011] The porous material is arranged on the upper surface of the vacuum adsorption assembly, and the porous material completely covers the adsorption holes on the upper surface of the vacuum adsorption assembly;

[0012] The membrane electrode to be tested is disposed on a porous material, and the vacuum pump is used to extract air from the cavity of the vacuum adsorption assembly to form a negative pressure; the helium gas source is used to spray an appropriate amount of helium gas onto the surface of the membrane electrode to be tested placed on the porous material; the helium mass spectrometer is used to perform mass spectrometry detection on the gas extracted by the vacuum pump to analyze the leakage points of the membrane electrode to be tested.

[0013] In some embodiments, the membrane electrode includes at least one of a fuel cell membrane electrode and an electrolyzed water membrane electrode, and / or the membrane electrode includes a cathode catalyst layer, a proton exchange membrane, and an anode catalyst layer.

[0014] In some embodiments, the porous material includes one of carbon paper, carbon cloth, carbon felt, stainless steel felt, or titanium felt, and / or the pore diameter of the porous material is 10 - 50 μm.

[0015] In some embodiments, the shape and size of the porous material are the same as the shape and size of the upper surface of the vacuum adsorption assembly.

[0016] In some embodiments, the shape of the membrane electrode to be tested is the same as the shape of the porous material, and the size is 2 - 5 mm larger than the size of the porous material, that is, the area of the porous material is the same as the area of the membrane electrode within the seal ring (including the seal ring) when the membrane electrode is assembled into the electrolytic cell and the seal ring presses the membrane electrode. The extra 2 - 5 mm area is defined to ensure that the seal ring can completely press the membrane electrode. During the operation of the electrolytic cell, it is only necessary to ensure that there is no leakage in the membrane electrode within the seal ring.

[0017] For example, when the membrane electrode to be tested is rectangular, the area of the membrane electrode larger than the porous material is in a shape of a double - square frame, with a width of 2 - 5 mm. The extra 2 - 5 mm area is to ensure that the seal ring can completely press the membrane electrode.

[0018] In the present application, the size of the membrane electrode is larger than that of the porous material, and the extra area has completely covered the vacuum adsorption assembly, ensuring that the helium gas sucked by the vacuum adsorption assembly all penetrates from directly above the membrane electrode, rather than leaking from the side boundary between the vacuum adsorption assembly and the membrane electrode.

[0019] Preferably, the upper surface of the vacuum adsorption assembly having adsorption holes is surrounded by a wrapping edge. More preferably, the height of the wrapping edge is equal to the height of the porous material, so that after the porous material is placed on the upper surface of the vacuum adsorption assembly, the porous material and the wrapping edge of the vacuum adsorption assembly form a plane, which is convenient for placing the membrane electrode to be tested thereon for detecting leakage points.

[0020] In some embodiments, the pore diameter of the adsorption holes on the upper surface of the vacuum adsorption assembly is 1 - 3 mm.

[0021] Preferably, the adsorption holes are arranged in the middle area of the upper surface of the vacuum adsorption component. Since the helium gas is pumped to the helium leak detector analyzer by the vacuum pump very quickly, and the response of the helium leak detector analyzer is also very fast, the setting of this position does not need to be strictly limited.

[0022] In some embodiments, the helium gas pressure of the helium gas source is 0.1 - 1.0 MPa.

[0023] A method for detecting the series leakage points of a membrane electrode uses the helium leak detection device described in any one of the above to detect the series leakage points of the membrane electrode.

[0024] In some embodiments, the detection method includes the following steps:

[0025] (1) Place the porous material on the upper surface of the vacuum adsorption component, and start the vacuum pump to extract the air in the cavity of the vacuum adsorption component to form a negative pressure state;

[0026] (2) Place the membrane electrode to be tested on the porous material. Due to the negative pressure inside the vacuum adsorption component, the external atmospheric pressure will tightly press the membrane electrode to be tested and the porous material on the upper surface of the vacuum adsorption component, thereby achieving stable adsorption;

[0027] (3) Turn on the helium mass spectrometer analyzer connected to the vacuum pump;

[0028] (4) Place the helium gas source above the membrane electrode to be tested, and spray helium gas at each position of the membrane electrode to be tested. Observe and record the value of the helium mass spectrometer analyzer every time a position is sprayed to analyze and obtain the series leakage points of the membrane electrode to be tested.

[0029] In some embodiments, the helium gas pressure in the helium gas source is 0.1 - 1.0 MPa.

[0030] In some embodiments, when the response value of the helium leak detector analyzer is more than 80 times the normal value, it is initially determined that there is a series leakage point in this area. At this time, spray helium gas slowly in this area to lock the specific series leakage point.

[0031] The beneficial effects of this application are:

[0032] 1. The operation is simple. Just place the membrane electrode to be tested flat on the porous material and start the device.

[0033] 2. The test time is short, and the response time of the helium mass spectrometer analyzer < 0.3 s.

[0034] 3. The detection method of this application can achieve non-destructive detection of membrane electrodes. Helium is an inert gas with extremely inactive chemical properties and does not react chemically with membrane electrodes, that is, it does not contaminate the membrane electrodes. At the same time, helium is a monoatomic gas, existing in the form of single atoms in the natural state, with extremely small size, capable of easily penetrating tiny pores with only a tiny pressure, and causing no damage to the membrane electrodes.

[0035] 4. The helium leak detection method has high precision, which is 300 times that of air detection.

[0036] 5. It has strong reliability. The helium mass spectrometer has a response signal to the leak detection gas helium, but no response to other gases. Therefore, it belongs to a unique leak detection instrument.

[0037] 6. It can perform qualitative and quantitative detection, indicating the location and size of the leak holes in the membrane electrode. Generally, the general detection method can only indicate the size of the leak holes in the membrane electrode. Description of the Drawings

[0038] Figure 1 It is a schematic diagram of the helium leak detection device of this application.

[0039] Figure 2 It is a schematic diagram of the helium leak detection device of this application.

[0040] Figure 3 It is an electrolyzed water membrane electrode.

[0041] Figure 4 It is a schematic diagram of the principle of conventional compressed air detection. Detailed Embodiments

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below. Apparently, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0043] For those without specific technical or conditions indicated in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments without the manufacturer indicated, they are all conventional products that can be obtained through regular channels.

[0044] Glossary:

[0045] The series leakage rate (sccm) of the membrane electrode refers to the series leakage flow rate of gas from the anode to the cathode of the membrane electrode per unit time under a certain pressure difference. Its unit is "standard cubic centimeters per minute" (sccm), which is used to characterize the airtightness of the membrane electrode.

[0046] The reading of the helium leak detector analyzer (Pa·m 3 / s) refers to the volume of gas passing through a certain leakage point per second measured in cubic meters and measured under a pressure difference of 100 kPa. This unit accurately reflects the gas leakage rate under specific conditions.

[0047] Reference Figure 1 and Figure 2 This application provides a helium leak detection device for a membrane electrode. The helium leak detection device includes:

[0048] A helium gas source 1, a membrane electrode to be tested 6, a porous material 2, a vacuum adsorption component 3, a vacuum pump 4, and a helium mass spectrometer 5;

[0049] Among them, the vacuum adsorption component 3 adopts a cavity design, and a plurality of adsorption holes are opened on its upper surface. The adsorption holes are communicated with the cavity inside the vacuum adsorption component 3; the vacuum adsorption component 3 is connected to one end of the vacuum pump 4, and the other end of the vacuum pump 4 is connected to the helium mass spectrometer 5;

[0050] The porous material 2 is arranged on the upper surface of the vacuum adsorption component 3, the membrane electrode to be tested 6 is arranged on the porous material 2, and the vacuum pump 4 is used to pump out the air in the cavity of the vacuum adsorption component 3 to form a negative pressure; the helium gas source 1 is used to spray an appropriate amount of helium gas on the surface of the membrane electrode to be tested 6 placed on the porous material 2; the helium mass spectrometer 5 is used to perform mass spectrometry detection on the gas extracted by the vacuum pump 4 to analyze the series leakage points of the membrane electrode to be tested.

[0051] In some embodiments, the membrane electrode includes at least one of a fuel cell membrane electrode and an electrolyzed water membrane electrode, and / or, the membrane electrode includes a cathode catalyst layer, a proton exchange membrane (referred to as a proton membrane for short), and an anode catalyst layer.

[0052] In some embodiments, the porous material includes one of carbon paper, carbon cloth, carbon felt, stainless steel felt, or titanium felt. The purpose is to increase the adsorption area with the membrane electrode and increase the gas channels. Due to the negative pressure inside the vacuum adsorption component 3, the action of the external atmospheric pressure will cause the membrane electrode 6 to be tested and the porous material 2 to be closely attached and adsorbed on the upper surface of the vacuum adsorption component 3.

[0053] In some embodiments, the pore diameter of the porous material is 10-50 μm; and / or, the shape and size of the porous material are the same as the shape and size of the upper surface of the vacuum adsorption component.

[0054] Generally speaking, the "pore size" of a proton exchange membrane is essentially a nanoscale ion channel of 1 - 5 nm; the pore size of the proton exchange membrane leakage point where leakage occurs is generally 50 μm - 1 mm; while the pore size of the porous material is 10 - 50 μm. The three are very different, and the pore size of the porous material will not affect the test results.

[0055] If porous material is not used, when the adsorption holes of the vacuum adsorption component directly adsorb the membrane electrode to be tested under negative pressure, it may damage the catalytic layer of the membrane electrode. Since the pore size of the adsorption holes is relatively large, between 1 - 3 mm, it is necessary to set a buffer layer of porous material between the two.

[0056] In some of these embodiments, such as Figure 3 For the electrolyzed water membrane electrode described above, the black area is the active area of the membrane electrode (the cathode and anode catalytic layers are respectively coated on both sides of the proton membrane), and the white area only has the proton membrane without a catalytic layer. The white area is generally used for connection and fixation, etc., such as the position of the pressure sealing ring during subsequent assembly. Therefore, the area of the membrane electrode larger than the porous material is set in this white area.

[0057] The size of the PEM electrolyzed water membrane electrode for a small electrolytic cell is 30*30 mm - 150*150 mm, and the width of the white area is generally 2 mm - 50 mm.

[0058] The size of the PEM electrolyzed water membrane electrode for an industrial electrolytic cell is 300*300 mm - 1200*1200 mm, and the width of the white area is generally 50 mm - 300 mm.

[0059] However, there may also be leakage points in the white area. Therefore, it is defined that the area of the membrane electrode larger than the porous material is the area after the pressure sealing ring when the membrane electrode is assembled into the electrolytic cell. The width of this square frame area is generally 2 mm - 5 mm. When the electrolytic cell is working, it only needs to ensure that there is no leakage in the membrane electrode within the sealing ring. As Figure 3 As shown, the dotted line is the sealing ring. If there are leakage points in the sealing ring (including the sealing ring) and the membrane electrode area within the sealing ring, it will affect the normal operation of the electrolytic cell. There is no problem if there are leakage points outside the dotted line because the environment outside the sealing ring is open.

[0060] In the technical solution of this application, it is defined that the size of the membrane electrode is larger than the size of the porous material, and the excess area completely covers the porous material. The purpose is to ensure that the helium gas sucked by the vacuum adsorption component all penetrates from directly above the membrane electrode, rather than leaking from the side boundary between the vacuum adsorption component and the membrane electrode.

[0061] In some of these embodiments, the upper surface of the vacuum adsorption assembly with adsorption holes is surrounded by a wrapping edge. More preferably, the height of the wrapping edge is equal to the height of the porous material, so that after the porous material is placed on the upper surface of the vacuum adsorption assembly, the porous material and the wrapping edge of the vacuum adsorption assembly form a plane, which is convenient for placing the membrane electrode under test on it to detect the series leakage points.

[0062] In some of these embodiments, the aperture of the adsorption holes on the upper surface of the vacuum adsorption assembly is 1-3 mm.

[0063] Preferably, the adsorption holes are arranged in the middle area of the upper surface of the vacuum adsorption assembly. Since the speed at which helium is pumped by the vacuum pump to the helium leak detector analyzer is very fast, and the response of the helium leak detector analyzer is also very fast, the setting of this position does not need to be strictly defined.

[0064] In some of these embodiments, the helium pressure of the helium source is 0.1-1.0 MPa.

[0065] The present application will be further described below in conjunction with specific embodiments, but is not limited thereto.

[0066] Embodiment

[0067] A helium leak detection method for an electrolyzed water membrane electrode includes the following operating steps:

[0068] See Figure 1 and Figure 2 . Place the porous material 2 on the upper surface of the vacuum adsorption assembly 3. The shape and size of the porous material are the same as those of the upper surface of the vacuum adsorption assembly. Start the vacuum pump 4 connected to the vacuum adsorption assembly 3 to pump out the air in the cavity of the vacuum adsorption assembly 3 to make it in a negative pressure state.

[0069] Place the membrane electrode 6 under test on the porous material 2. The area of the membrane electrode 6 under test that is larger than the porous material 2 is in a zigzag shape, and the width is 2 mm - 5 mm (see Figure 3 ). The porous material is one of porous materials such as carbon paper, carbon cloth, carbon felt, stainless steel felt or titanium felt. The purpose is to increase the adsorption area with the membrane electrode and increase the gas channels.

[0070] Due to the negative pressure inside the vacuum adsorption assembly 3, the action of the external atmospheric pressure will cause the membrane electrode 6 under test and the porous material 2 to be closely attached and adsorbed on the upper surface of the vacuum adsorption assembly 3.

[0071] Open the helium mass spectrometer 5 connected to the vacuum pump 4.

[0072] Place the helium gas source 1 above the membrane electrode 6 to be tested, and spray helium gas at various positions of the membrane electrode 6 to be tested. Observe and record the values of the helium mass spectrometer 5 each time a position is sprayed to analyze and obtain the leakage points of the membrane electrode to be tested.

[0073] If there is leakage in the membrane electrode, the helium gas passes through the leakage point, through the porous material and the vacuum adsorption component, and reaches the helium mass spectrometer. The working principle of the mass spectrometer is to collect gas samples in the test piece and ionize them, and then, according to the different characteristics of the mass-to-charge ratios of gas ions of different types, use the magnetic deflection separation principle to distinguish the gases. The selected helium mass spectrometer only has a response signal to helium gas in the leak detection gas and has no response to other gases. Therefore, it is a unique leak detection instrument. When a signal response appears, it indicates that helium gas has entered the helium mass spectrometer through the leakage holes of the membrane electrode of the test piece, thereby indicating the position and size of the leakage holes, and qualitative and quantitative detection can be carried out.

[0074] Select 15 newly produced electrolyzed water membrane electrodes (Samples 1-15). The electrolyzed water membrane electrode includes a three-in-one structure of a cathode catalyst layer, a proton exchange membrane, and an anode catalyst layer. Generally, the thickness of the proton membrane of the electrolyzed water membrane electrode is 50-200 um, the thickness of the cathode catalyst layer is 8-12 um, and the thickness of the anode catalyst layer is 2-4 um. The area of the electrolyzed water membrane electrode larger than the porous material is in a zigzag shape, with a width of 2-5 mm.

[0075] Detect the 15 electrolyzed water membrane electrodes by the helium leak detection method to obtain Examples 1-15.

[0076] And use the conventional compressed air detection method for comparison. The steps of the conventional compressed air detection method are as Figure 4 shown, and specifically include the following steps:

[0077] S1. Install the membrane electrode into a high-pressure-resistant stainless steel fixture. Since the pressure on the cathode side of the electrolyzed water membrane electrode is as high as 3 MPa during operation, the air pressure during compressed air detection also needs to be 3 MPa:

[0078] S2. Use an external gas source to fill the buffer tank with compressed air, and the pressure controller controls the air pressure in the buffer tank, such as 3 Mpa.

[0079] S3. Open the inflation valve, and the buffer tank quickly inflates the cathode cavity. The cathode cavity and the buffer tank are at the same pressure, both 3 Mpa, and then close the inflation valve.

[0080] S4. Open the test valve, collect the data of the gas flow meter, and continue for 1 h (the time can be set) to determine the test result.

[0081] S5. Close the test valve, open the pressure relief valve, and the cathode cavity returns to normal pressure, and the test is completed.

[0082] Disadvantages of conventional compressed air detection methods:

[0083] 1. High-pressure testing is required, and high-pressure gas is likely to damage the membrane electrode.

[0084] 2. Due to the need for high-pressure testing, the fixtures clamped around the membrane electrode need to be tightened with high torque to prevent air leakage. When tightened with high torque, it is easy to damage the membrane electrode.

[0085] 3. The proton membrane of the electrolyzed water membrane electrode has a thickness of 50-200 μm. Since air molecules are large, it takes a long time to test to pass through the proton membrane and detect the value.

[0086] 4. It can only detect whether there is leakage, but cannot detect the position of the leakage hole.

[0087] 5. For industrial-grade electrolyzers, the stainless-steel fixtures for testing weigh more than 50 kg, and mechanical equipment is needed to assist in handling, disassembling and assembling.

[0088] It can be seen from this that conventional compressed air testing has a cumbersome assembly process, a long testing time, and the high pressure during assembly may damage the membrane electrode.

[0089] The results of each embodiment are shown in Table 1. The series leakage rate (SCCM) of the membrane electrode obtained by the conventional compressed air detection method is directly read by the flow meter. The SCCM of the helium leak detector in this application is obtained by converting according to the "reading of the helium leak detector" to facilitate the comparison between the technical solution of this application and the conventional compressed air detection method.

[0090] Table 1. Detection results of each embodiment

[0091]

[0092]

[0093] Spray an appropriate amount of helium gas from the helium gas source above the membrane electrode to various positions of the electrolyzed water membrane electrode. Since the response of the helium leak detector is very fast, with a response time < 0.3 s, during operation, while continuously spraying helium gas at different positions of the electrolyzed water membrane electrode, observe the helium leak detector at the same time. Because the membrane electrode itself also has tiny pores, helium atoms can penetrate the membrane electrode, and there will be a tiny response signal in the helium mass spectrometer. The response value at the position where there is no series leakage in the membrane electrode is 1.1-1.3×10 -6 Pa·m 3 / s. When the response value of the helium leak detector is more than 80 times the normal value, it proves that there is a series leakage point in the area passed through in 0.3 s. At this time, slowly spray helium gas in this area to lock the specific series leakage point.

[0094] As shown in Table 1, there are series leakage points in samples 5, 13, and 14. At the same time, the response value of the leakage point measured again here is 120×10- 6 Pa·m 3 / s. At the same time, 2 leakage points were found in two positions of sample 13. There are no leakage points in other samples, meeting the requirements.

[0095] Generally speaking, the response value of the helium mass spectrometer at positions without leakage points is generally very small. When helium gas sweeps to the leakage point, the response value of the analyzer immediately becomes 120×10 -6 Pa·m 3 / s, indicating that there is a leakage point here, so as to qualitatively and quantitatively detect the membrane electrode.

[0096] For a gas flow meter, the test accuracy is related to the test range. The smaller the range, the higher the accuracy. And the helium detection accuracy is 300 times that of air detection accuracy. Therefore, there are some deviations in the data obtained by detecting different samples with the same helium detection result using a conventional gas flow meter. Moreover, in the detection result of the gas flow meter, sample 13 is twice that of sample 5 and sample 14 because 2 leakage points were found in two positions of sample 13. Air detection needs to be installed in a fixture for testing. The total leakage amount is obtained by superimposing all the leakage points in the test area in the fixture, which is a face-to-face detection. Therefore, it can only detect whether there is a leakage point and cannot indicate the position and number of leakage points. However, the helium detection of this application is a point-to-point detection, which can indicate the position and number of leakage points.

[0097] The electrolyzed water membrane electrodes of Examples 1-15 were assembled into single cells for performance testing, and the results are shown in Table 2.

[0098] Table 2. Performance tested for each example

[0099] Embodiment <![CDATA[3A / cm 2 @V]]> Embodiment 1 1.835 Embodiment 2 1.851 Embodiment 3 1.845 Embodiment 4 1.833 Embodiment 5 0.774 Embodiment 6 1.846 Embodiment 7 1.841 Embodiment 8 1.838 Embodiment 9 1.831 Embodiment 10 1.844 Embodiment 11 1.839 Embodiment 12 1.836 Embodiment 13 0.556 Embodiment 14 0.927 Embodiment 15 1.856

[0100] Leakage in the membrane electrode will cause the reactants to pass directly through, reducing the effective reaction area. The voltage will usually drop significantly, possibly dropping to 50% or lower of the normal range, and may also cause an internal short circuit, and the voltage may suddenly drop to close to 0V.

[0101] In Examples 5, 13 and 14, the helium detection response value is significantly larger than that of normal samples (both the proton exchange membrane and the catalyst layer have microporous structures, and these micropores allow gases to pass through under certain conditions, resulting in gas permeation). After retesting with air and performing electrical performance testing, the results all prove that the membrane electrode has leakage. Generally speaking, the helium detection time for an electrolyzed water membrane electrode of a small electrolytic cell is controlled within 10s.

[0102] In summary, since the helium leak detection time for each membrane electrode is < 10 s, while the detection time using compressed air is about 5 min. At the same time, the helium leak detection pressure is low, only 0.25 MPa, while compressed air detection requires up to 3 MPa to ensure the detection accuracy. In addition, the detection accuracy of helium leak detection is 300 times that of compressed air detection. All of the above demonstrate the superiority of helium leak detection in this application.

[0103] Industrial Application Example 1

[0104] The helium leak detection device and its detection method for the electrolyzed water membrane electrode of this application can be used to test newly prepared membrane electrodes. If the helium leak detection result is above 100×10 -6 Pa·m 3 / s, it proves that the membrane electrode has a series leak and cannot be used. At the same time, this method can also indicate the location of the series leak, so as to conduct cause analysis.

[0105] Example: 100 newly prepared membrane electrodes were detected, and the detection method was the same as above.

[0106] The results showed that among them, 3 membrane electrodes had test results greater than 100×10 -6 Pa·m 3 / s under a helium leak detection pressure of 0.25 MPa, proving that there was a series leak. After being verified again by voltage testing, the voltage of these 3 membrane electrodes was lower than 1 V at 3 A / cm 2 , once again proving that there was a series leak. The yield rate of this batch was 97%. The qualified electrolyzed water membrane electrodes were encapsulated with a frame to form a five-in-one membrane electrode assembly, or directly a three-in-one membrane electrode assembly, for electrolytic cell assembly or sale. Therefore, this application provides a more convenient and rapid method to determine whether the produced membrane electrodes meet the specifications, which is suitable for industrial promotion.

[0107] Industrial Application Example 2

[0108] During the operation of the qualified electrolyzed water membrane electrode in the electrolytic cell, if it is found that the voltage is significantly low, the membrane electrode is removed and placed in this device for detection. If the helium leak detection result is above 100×10 -6 Pa·m 3 / s, it proves that the membrane electrode has a series leak and cannot be used; at the same time, according to the location of the series leak, cause analysis is carried out.

[0109] Because when the qualified and non-series-leaking membrane electrode is assembled into the electrolytic cell and the voltage becomes significantly low during operation, the series leak at this time may be that a small hard object on other components of the electrolytic cell pierces the membrane electrode, or the membrane electrode is damaged during transportation, or the membrane electrode undergoes electrochemical damage. All of the above situations can be detected and the cause analyzed using the method of this application.

[0110] The above is a further detailed description of the present invention and should not be construed as a limitation on the specific implementation of the present invention. For those of ordinary skill in the technical field to which the present invention pertains, any simple deduction or substitution without departing from the concept of the present invention falls within the protection scope of the present invention.

Claims

1. A helium detection device for a membrane electrode, characterized in that, The helium leak detection device includes: a helium gas source, a membrane electrode to be tested, a porous material, a vacuum adsorption assembly, a vacuum pump, and a helium mass spectrometer; Among them, the vacuum adsorption assembly adopts a cavity design, and a plurality of adsorption holes are opened on its upper surface. The adsorption holes communicate with the cavity inside the vacuum adsorption assembly; the vacuum adsorption assembly is connected to one end of the vacuum pump, and the other end of the vacuum pump is connected to the helium mass spectrometer; The porous material is arranged on the upper surface of the vacuum adsorption assembly, and the porous material completely covers the adsorption holes on the upper surface of the vacuum adsorption assembly; The membrane electrode to be tested is arranged on the porous material. The vacuum pump is used to pump out the air in the cavity of the vacuum adsorption assembly to form a negative pressure; the helium gas source is used to spray an appropriate amount of helium gas onto the surface of the membrane electrode to be tested placed on the porous material; the helium mass spectrometer is used to perform mass spectrometry detection on the gas extracted by the vacuum pump to analyze the leakage points of the membrane electrode to be tested.

2. The helium leak detection device according to claim 1, wherein The membrane electrode includes at least one of a fuel cell membrane electrode and an electrolyzed water membrane electrode, and / or the membrane electrode includes a cathode catalyst layer, a proton exchange membrane, and an anode catalyst layer.

3. The helium leak detection device according to claim 1, wherein The porous material includes one of carbon paper, carbon cloth, carbon felt, stainless steel felt, or titanium felt, and / or the pore size of the porous material is 10-50 μm.

4. The helium leak detection device according to claim 1 or 3, characterized in that, The shape and size of the porous material are the same as the shape and size of the upper surface of the vacuum adsorption assembly.

5. The helium leak detection device according to any one of claims 1-4, characterized in that, The shape of the membrane electrode to be tested is the same as the shape of the porous material, and the size is 2-5 mm larger than the size of the porous material, and / or the area of the porous material is the same as the area of the membrane electrode within the seal ring and within the seal ring when the membrane electrode is assembled into the electrolytic cell and pressed with the seal ring.

6. The helium leak detection device according to any one of claims 1-4, characterized in that, The aperture of the adsorption holes on the upper surface of the vacuum adsorption assembly is 1-3 mm.

7. The helium leak detection device according to any one of claims 1-4, characterized in that, The helium gas pressure of the helium gas source is 0.1-1.0 MPa.

8. A method for detecting leakage points in a membrane electrode string, characterized in that: Use the helium leak detection device according to any one of claims 1-7 to detect the leakage points of the membrane electrode.

9. The detection method according to claim 8, wherein The detection method includes the following steps: (1) Place the porous material on the upper surface of the vacuum adsorption assembly, and start the vacuum pump to pump out the air in the cavity of the vacuum adsorption assembly to make it in a negative pressure state; (2) Place the membrane electrode to be tested on the porous material; (3) Turn on the helium mass spectrometer connected to the vacuum pump; (4) Place the helium gas source above the membrane electrode to be tested, and spray helium gas at each position of the membrane electrode to be tested. Observe and record the value of the helium mass spectrometer every time a position is sprayed to analyze and obtain the leakage points of the membrane electrode to be tested.

10. The detection method according to claim 9, wherein The helium gas pressure in the helium gas source is 0.1-1.0 MPa.

Images