Membrane electrode pinhole detection device and detection method thereof

Abstract

The invention relates to a membrane electrode pinhole detection device and a detection method thereof, the membrane electrode pinhole detection device comprises a lamp panel, a connecting device, a concentric-square-shaped fixing frame, a clamping device, a water source dropper head and an air source nozzle; one end of the connecting device is connected with the lamp panel; the rectangular-ambulatory-plane fixing frame is connected with one end of the connecting device, and the rectangular-ambulatory-plane fixing frame is detachably installed above the lamp panel through the connecting device; the clamping device is arranged on the concentric-square-shaped fixing frame and is used for clamping the edge of a proton membrane of a membrane electrode, so that the membrane electrode is suspended above the lamp panel; the water source dropper head is arranged above the rectangular-ambulatory-plane fixing frame and can move to the position right above a needle hole of the membrane electrode; the air source nozzle is located between the lamp panel and the rectangular-ambulatory-plane fixing frame and can move to the position under a needle hole of a membrane electrode. The device is simple in structure, low in cost, simple and reliable in operation method and short in test time.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and specifically to a membrane electrode pinhole detection device and a detection method thereof. Background Art

[0002] Proton exchange membrane (PEM) water electrolysis hydrogen production technology is regarded as one of the core technologies for green hydrogen production due to its fast start-stop characteristics and high adaptability to the volatility of renewable energy power generation. In a PEM electrolyzer, the membrane electrode, as the core carrier of the electrochemical reaction, is composed of an anode catalyst layer and a cathode catalyst layer coated on both sides of the proton membrane, and directly determines the efficiency and stability of water electrolysis hydrogen production.

[0003] However, during the preparation of the membrane electrode, two types of pinhole defects, non-through pinholes and through pinholes, are likely to occur in its active area (catalyst layer area). Non-through pinholes are mainly caused by defects in the catalyst layer material or coating process deviations, resulting in local non-coverage of the proton membrane. Such pinholes have no substantial impact on the performance of the membrane electrode; while through pinholes (perforations) are caused by mechanical damage or process out-of-control during production, resulting in complete penetration of the proton membrane. Such defects will cause serious consequences, such as the cross-membrane mixing of reaction gases (hydrogen / oxygen), reducing the electrolysis efficiency and increasing energy consumption; causing the risk of hydrogen-oxygen mixing and explosion; accelerating the corrosion of the membrane electrode, shortening the equipment life and increasing the maintenance cost.

[0004] Currently, the detection of through pinholes in the industry mainly relies on traditional airtightness testing methods, that is, pressurizing the membrane electrode after it is installed in the electrolyzer to detect gas leakage. This method has significant defects:

[0005] Complicated operation: It is necessary to completely assemble the electrolyzer, which takes up to several hours;

[0006] Risk of high-pressure damage: The high-pressure environment during testing is likely to cause irreversible damage to the membrane electrode;

[0007] Inability to locate defects: It can only judge the existence of leakage and cannot accurately identify the position and nature of the pinholes (through or non-through).

[0008] Therefore, there is an urgent need to develop a detection method and device that are simple, efficient, non-destructive, and can accurately distinguish through pinholes, so as to improve the reliability of membrane electrode quality control and reduce the manufacturing and maintenance costs of PEM electrolyzers. Summary of the Invention

[0009] Based on this, it is necessary to provide a membrane electrode pinhole detection device and a detection method thereof, aiming to solve the technical problems existing in the prior art.

[0010] To achieve the above object, the present invention provides a technical solution:

[0011] A membrane electrode pinhole detection device, comprising:

[0012] Light board;

[0013] Connecting device, one end of the connecting device is connected to the light board;

[0014] Square frame, the square frame is connected to one end of the connecting device, and the square frame is detachably mounted above the light board through the connecting device;

[0015] Clamping device, the clamping device is arranged on the square frame, and the clamping device is used to clamp the edge of the proton membrane of the membrane electrode, so that the membrane electrode is suspended above the light board;

[0016] Water source dropper head, the water source dropper head is arranged above the square frame, and the water source dropper head can move to directly above the pinhole of the membrane electrode;

[0017] Gas source nozzle, the gas source nozzle is located between the light board and the square fixing frame, and the gas source nozzle can move to directly below the pinhole of the membrane electrode.

[0018] Wherein, the membrane electrode includes a fuel cell membrane electrode and an electrolyzed water membrane electrode. Preferably, when the membrane electrode is an electrolyzed water membrane electrode, the amount of water droplets dropped by the water source dropper head on the pinhole of the electrolyzed water membrane electrode is one drop of water.

[0019] Since the thickness of the proton exchange membrane of the PEM electrolyzed water membrane electrode is between 50 and 200 um and has high mechanical strength, if the whole membrane absorbs water, it is easy to twist and deform after swelling and is difficult to return to a flat state, which affects the subsequent assembly of the electrolytic cell. In this application, only one drop of water is dropped at the pinhole, and the water droplet just covers the surface of the pinhole. The electrolyzed water membrane electrode only has a slight deformation at the place where the water is dropped on the surface of the pinhole. After testing, the water is blotted dry, and the electrolyzed water membrane electrode can be restored without affecting the subsequent assembly of the electrolytic cell.

[0020] Preferably, the connecting device includes a connecting rod and a screw. One end of the connecting rod is fixed on the light board, and the other end of the connecting rod is detachably connected to the square frame through the screw.

[0021] Preferably, the shape and size of the square frame can be replaced to adapt to different models of membrane electrodes.

[0022] Preferably, the clamping device includes a plurality of clips, and the plurality of clips are symmetrically distributed on the edge of the square frame to uniformly clamp the proton membrane.

[0023] Preferably, a rubber layer is attached to the inner side of the clip.

[0024] Preferably, the moving path of the gas source nozzle is parallel to the plane of the light board to align with the pinhole position of the membrane electrode.

[0025] The present invention also provides a method for detecting pinholes in a membrane electrode, comprising the following steps:

[0026] Fix the membrane electrode on a square-shaped fixing frame through a clamping device, making it suspended above the lamp board;

[0027] Irradiate the active area of the membrane electrode through the lamp board to identify the position of the pinhole;

[0028] Control the water source dropper head to drip water droplets on the surface of the pinhole, so that the water droplets completely cover the pinhole;

[0029] Move the gas source nozzle to directly below the pinhole of the membrane electrode and apply a preset air pressure;

[0030] Observe whether bubbles are generated on the surface of the water droplet. Specifically, if bubbles exist, it is determined that the pinhole is a through-hole defect and the membrane electrode is scrapped.

[0031] Preferably, the applied air pressure range is 0.1 MPa - 0.5 MPa, and the duration is 5 seconds to 20 seconds.

[0032] Preferably, the covering area of the water droplet is larger than the diameter of the pinhole. Generally, the covering area of the water droplet is 3 to 5 times the diameter of the pinhole. Preferably, the gas source of the compressed gas source nozzle includes at least one of air, nitrogen, oxygen, and helium.

[0033] Advantages of the present invention:

[0034] By means of positioning the pinhole, covering with water droplets and combining with air pressure detection, the present invention does not need to install the membrane electrode into the electrolytic cell, the detection time is shortened from several hours to several minutes, and the whole process is operated at low pressure. Only gas and water are used during the test, and the normal operation of the membrane electrode is the process of electrolyzing water to generate gas, so the membrane electrode is not polluted or damaged, that is, non-destructive detection.

[0035] The present invention utilizes the principle of water droplet covering and air pressure penetration. Only through-hole pinholes will generate bubbles, which can clearly distinguish non-through-hole pinholes (no need to be processed) from through-hole pinholes (to be scrapped), and solves the problem that traditional airtightness tests cannot locate and qualitatively determine defects.

[0036] The device of the present invention adopts a detachable square-shaped fixing frame and a rubber clamping structure, without complex assembly, and ordinary operators can complete the detection; moreover, the manufacturing cost of the device is low, compatible with multiple membrane electrode models, and significantly reduces the input and maintenance costs of detection equipment.

[0037] The present invention can flexibly support the detection requirements of various membrane electrodes (such as circular, rectangular, and irregular-shaped) by replacing the square-shaped fixing frame adapted to different shapes / sizes, and meets the diverse production scenarios of PEM electrolytic cells.

[0038] The present invention can avoid the potential explosion risk of hydrogen-oxygen mixture in traditional high-voltage tests. Meanwhile, it can quickly identify and eliminate membrane electrodes with through-pinholes, reducing the potential safety hazards during the operation of the electrolyzer from the source.

[0039] Through structural innovation and optimization of the detection method, the present invention solves the pain points of low efficiency, high damage risk, and inability to accurately identify defects in traditional technologies, providing an integrated solution with high efficiency, safety, and low cost for the quality control of membrane electrodes in PEM electrolyzers. Brief Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0041] Figure 1 It is a membrane electrode pinhole detection device in an embodiment;

[0042] Figure 2 It is a partial schematic diagram of the membrane electrode pinhole detection device in an embodiment;

[0043] Figure 3 It is a partial schematic diagram of the clamping device of the membrane electrode pinhole detection device in an embodiment;

[0044] Figure 4 It is a partial schematic diagram of the membrane electrode pinhole detection device in an embodiment;

[0045] Figure 5 It is a schematic diagram of a membrane electrode in an embodiment.

[0046] In the figure, 100, lamp board; 200, connecting device; 210, connecting rod; 220, screw; 300, square fixed frame; 400, clamping device; 410, clip; 420, rubber layer; 500, water source dropper head; 600, gas source nozzle; 700, membrane electrode; 710, proton membrane; 720, active area; 730, pinhole; 800, water droplet

[0047] The realization, functional features, and advantages of the object of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. Detailed Embodiments

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0050] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, "and / or" throughout the text includes three scenarios. Taking A and / or B as an example, it includes the technical solution of A, the technical solution of B, and the technical solution that both A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0051] As Figure 1 shown, a membrane electrode pinhole detection device includes a lamp board 100, a connecting device 200, a rectangular fixed frame 300, a clamping device 400, a water source dropper head 500, and an air source nozzle 600.

[0052] One end of the connecting device 200 is connected to the lamp board 100;

[0053] The rectangular fixed frame 300 is connected to one end of the connecting device 200, and the rectangular fixed frame 300 is detachably mounted above the lamp board 100 through the connecting device 200;

[0054] The clamping device 400 is arranged on the rectangular fixed frame 300. The clamping device 400 is used to clamp the edge of the proton membrane 710 of the membrane electrode 700, so that the membrane electrode 700 is suspended above the lamp board 100; the lamp board 100 is used to observe whether there are pinholes in the active area 720 of the membrane electrode 700.

[0055] The water source dropper head 500 is arranged above the square frame fixing bracket 300, and the water source dropper head 500 can be moved to directly above the pinhole 730 of the membrane electrode 700;

[0056] The gas source nozzle 600 is located between the lamp board 100 and the square frame fixing bracket, and the gas source nozzle can be moved to directly below the pinhole 730 of the membrane electrode 700.

[0057] In some embodiments, as Figure 2 shown, the connecting device 200 includes a connecting rod 210 and a screw 220. One end of the connecting rod 210 is fixed on the lamp board 100, and the other end of the connecting rod 210 is detachably connected to the square frame fixing bracket 300 through the screw 220.

[0058] In some embodiments, the shape and size of the square frame fixing bracket 300 can be replaced to adapt to different models of membrane electrodes 700. When the membrane electrode 700 is changed in model, only the corresponding square frame fixing bracket 300 needs to be replaced, so as to be compatible with membrane electrodes 700 of various sizes and shapes. More specifically, the detection of the membrane electrode of the present invention can be the detection of the membrane electrode at the time of factory shipment, or the detection of the membrane electrode that has already been working.

[0059] In some embodiments, the clamping device 400 includes a plurality of clips 410, and the plurality of clips 410 are symmetrically distributed on the edge of the square frame fixing bracket 300 to uniformly clamp the proton membrane 710.

[0060] In some embodiments, as Figure 3 shown, a rubber layer is pasted on the inner side of the clip 410 to prevent damage to the proton membrane 710 of the membrane electrode 700 when clamping it.

[0061] In some embodiments, the moving path of the gas source nozzle 600 is parallel to the plane of the lamp board 100 to align with the position of the pinhole 730 of the membrane electrode 700.

[0062] The present invention also provides a method for detecting the pinhole 730 of a membrane electrode 700, including the following steps:

[0063] S100. Fix the membrane electrode 700 on the square frame fixing bracket 300 through the clamping device 400 so that it is suspended above the lamp board 100; as Figure 4 shown, the membrane electrode 700 is composed of a proton membrane 710 and an active area 720, wherein the active area 720 specifically refers to the area of the proton membrane 710 covered by the catalyst layer in the membrane electrode 700 (MEA), and is the core functional area where the electrochemical reaction (water is decomposed into hydrogen and oxygen) occurs.

[0064] S200. Irradiate the active area 720 of the membrane electrode 700 through the lamp board 100 to identify the position of the pinhole 730;

[0065] S300. Control the water source dropper head 500 to drop water droplets 800 on the surface of the pinhole 730 so that the water droplets 800 completely cover the pinhole 730; Specifically, the water source dropper head 500 can use an automated system. For example, a CCD visual system locates the pinhole 730, feeds the position signal to the moving module of the water source dropper head 500, so that the water source dropper head 500 moves to the position of the pinhole 730, and the water source dropper head 500 controls the switch through a solenoid valve.

[0066] S400. Move the gas source nozzle 600 to directly below the pinhole 730 of the membrane electrode 700 and apply a preset air pressure; Specifically, the gas source nozzle 600 can use an automated system. For example, a CCD visual system locates the pinhole 730, feeds the position signal to the moving module of the gas source nozzle 600, so that the gas source nozzle 600 moves to the position of the pinhole 730, and the gas source nozzle 600 controls the switch through a solenoid valve.

[0067] S500. Observe whether bubbles are generated on the surface of the water droplet 800. Specifically, if bubbles exist, it is determined that the pinhole 730 is a through defect and the membrane electrode 700 is scrapped. If no bubbles are generated, it indicates that the membrane electrode 700 is qualified and can be further bonded to the proton exchange membrane.

[0068] In some embodiments, the applied air pressure ranges from 0.1 MPa to 0.5 MPa, and the duration is from 5 seconds to 20 seconds.

[0069] In some embodiments, the coverage area of the water droplet 800 is 3 to 5 times larger than the diameter of the pinhole 730.

[0070] In some embodiments, the gas source of the compressed gas source nozzle 600 includes at least one of air, nitrogen, oxygen, and helium, and generally compressed gas is used.

[0071] The specific detection conditions of each embodiment are shown in Table 1.

[0072] Table 1 Detection conditions of each embodiment

[0073]

[0074] Assemble the electrolyzed water membrane electrodes of Examples 1 to 7 into a single cell and conduct a performance test. The results are shown in Table 2.

[0075] Table 2 Performance tested for each embodiment

[0076]

[0077] As can be seen from Table 2, perforation of the membrane electrode allows reactants to pass directly through, reducing the effective reaction area. The voltage usually drops significantly, falling to 50% or less of the normal range (≥1.8V). It may also cause an internal short circuit, and the voltage may suddenly drop to near 0V.

[0078] The detection results of Example 1 and Example 4 were bubbling, indicating that the pinholes were caused by perforation. During the electrical performance test, the low voltage further proved that the pinholes were caused by perforation. At the same time, it also proved the reliability of the electrolytic water membrane electrode detection device and its detection method provided by the present invention.

[0079] Comparative Example 1

[0080] When using ordinary metal clips (without a rubber layer) to clamp the membrane electrode, it was found that the damage rate of the edge of the proton membrane increased after detection (the damage rate increased from 0.5% to 15%), proving the necessity of the rubber layer.

[0081] Comparative Example 2

[0082] In the prior art, when the membrane electrode is installed in a fixture with a gas flow field, the test air pressure will cause the membrane electrode to move closer from the high-pressure side to the low-pressure side. After detection, it was found that the damage rate of the active area of the membrane electrode on the low-pressure side by the flow field increased (the damage rate increased from 0% to 20%), while the suspended membrane electrode effectively avoided this risk.

[0083] Comparative Example 3

[0084] The prior art detects the entire surface of the membrane electrode and cannot indicate the position of the pinhole points. However, the present invention solves this problem by means of lamp board searchlight and dripping and blowing air. By analyzing the pinholes, it can be judged whether it is due to raw material defects or production out-of-control, guiding production improvement, and increasing the production yield from 90% to 98%.

[0085] Test Example 1

[0086] Test the influence of different air pressure ranges (0.1 - 0.5 MPa) on bubble detection:

[0087] When detected with 0.1 MPa, the bubble formation speed is slow and the amount of bubbles is small.

[0088] When detected with 0.2 MPa, the bubble formation speed is relatively slow and the amount of bubbles is relatively small.

[0089] When detected with 0.3 MPa, the bubble formation speed is fast, the amount of bubbles is large, and the bubble formation is the most stable.

[0090] When detected with 0.4 MPa, the bubble formation speed is fast, the amount of bubbles is large, but the bubble formation is unstable, and the bubble water splashes slightly around.

[0091] When detected at 0.5 MPa, the bubble formation speed is extremely fast, the amount of bubbles is extremely large, the bubble formation is extremely unstable, the bubble water splashes fly in all directions, and the water droplets covering the pinholes splash out within 3 seconds.

[0092] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the concept of the present invention, or direct / indirect application in other related technical fields are all included in the patent protection scope of the present invention.

Claims

1. A membrane electrode pinhole detection device, characterized in that, Comprising: A lamp board; A connecting device, one end of the connecting device being connected to the lamp board; A square-frame fixing bracket, the square-frame fixing bracket being connected to one end of the connecting device, and the square-frame fixing bracket being detachably mounted above the lamp board through the connecting device; a membrane electrode to be tested is disposed on the square-frame fixing bracket; A clamping device, the clamping device being disposed on the square-frame fixing bracket, and the clamping device being used for clamping the edge of the proton membrane of the membrane electrode to make the membrane electrode suspended above the lamp board; A water source dropper head, the water source dropper head being disposed above the square-frame fixing bracket, and the water source dropper head being movable to directly above the pinhole of the membrane electrode to drip water droplets to cover the surface of the pinhole; A gas source nozzle, the gas source nozzle being located between the lamp board and the square-frame fixing bracket, and the gas source nozzle being movable to directly below the pinhole of the membrane electrode for observing whether bubbles are generated on the surface of the water droplet.

2. The membrane electrode pinhole detection device according to claim 1, characterized in that The membrane electrode includes a fuel cell membrane electrode and an electrolyzed water membrane electrode.

3. The membrane electrode pinhole detection device according to claim 1, characterized in that The light intensity of the high-intensity lamp board is 100 to 600 lumens.

4. The membrane electrode pinhole detection device according to claim 1, characterized in that The connecting device includes a connecting rod and a screw, one end of the connecting rod being fixed on the lamp board, and the other end of the connecting rod being detachably connected to the square-frame fixing bracket through the screw.

5. The membrane electrode pinhole detection device according to claim 1, characterized in that The clamping device includes a plurality of clips, and the plurality of clips are symmetrically distributed on the edge of the square-frame fixing bracket to uniformly clamp the membrane electrode.

6. The membrane electrode pinhole detection device according to claim 5, wherein A rubber layer is attached to the inner side of the clip.

7. A method for detecting pinholes in a membrane electrode, using the device according to any one of claims 1-6, characterized in that, Including the following steps: Fixing the membrane electrode on the square-frame fixing bracket through the clamping device to make it suspended above the lamp board; Irradiating the active area of the membrane electrode through the lamp board to identify the position of the pinhole; Controlling the water source dropper head to drip water droplets on the surface of the pinhole to make the water droplets completely cover the pinhole; Moving the gas source nozzle to directly below the pinhole of the membrane electrode and applying a preset air pressure; Observing whether bubbles are generated on the surface of the water droplet.

8. The method according to claim 7, wherein The applied air pressure range is 0.1 MPa - 0.5 MPa, and the duration is 5 seconds to 20 seconds.

9. The method according to claim 7, wherein The covering area of the water droplet is larger than the diameter of the pinhole.

10. The method according to claim 7, characterized in that, The gas source of the compressed gas source nozzle includes at least one of air, nitrogen, oxygen, and helium.

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