Off-line test method for binding force of proton exchange membrane or CCM

Abstract

The invention provides an off-line test method for binding force of a proton exchange membrane or CCM, which comprises the following steps: preparing a to-be-tested sample, adding ultrapure water into a high-pressure tank, immersing the sample in water, sealing the high-pressure tank, pressurizing to preset pressure, maintaining the pressure, quickly releasing the pressure to enable the water to release a large number of bubbles to impact the sample, and pressurizing and depressurizing for multiple times, so as to test the binding force of the proton exchange membrane or the CCM. Compared with the prior art, the method has the following beneficial effects that the impact of bubbles on a film or a catalyst layer interface in actual operation can be simulated, the operation is simple and convenient, the binding force can be qualitatively or semi-quantitatively evaluated by directly observing whether the sample is layered or the catalyst layer falls off, and the method is high in practicability and high in practicability. The result is intuitive and easy to understand, evaluation under different impact strengths can be realized by adjusting parameters such as pressure and dwell time, and the method is suitable for testing the binding force of various proton exchange membranes and CCM.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane electrolyzer technology, and specifically relates to an offline testing method for the bonding force of proton exchange membranes or CCMs. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) boasts advantages such as high efficiency, cleanliness, and low-temperature start-up, making it a promising application in fields like new energy vehicles and distributed power generation. The proton exchange membrane (PEM) is one of the core components of PEMWE, and its performance directly affects the efficiency and lifespan of the electrolyzer. The catalyst membrane (CCM), composed of the proton exchange membrane and the catalyst layers coated on both sides, is the core region where the electrochemical reaction occurs.

[0003] In the preparation and operation of PEMWEs, the interlayer bonding of the proton exchange membrane (for composite membranes) and the bonding between the catalyst layer and the proton exchange membrane in the CCM are crucial performance indicators. Insufficient bonding can lead to membrane delamination and catalyst layer detachment, severely affecting the performance and durability of the electrolyzer. Therefore, developing a simple and effective offline testing method to evaluate the bonding of PEMs or CCMs is of great significance for membrane material selection, process optimization, and battery performance prediction.

[0004] Existing technologies include cross-cut adhesion testing, tensile testing, and peeling testing. However, the cross-cut adhesion and tensile testing methods are difficult to operate for thin and flexible proton exchange membranes or CCMs and may introduce human error. Traditional peeling testing often requires the preparation of samples of specific shapes, which is cumbersome and may not be able to realistically simulate conditions such as bubble impacts that may be encountered during the operation of fuel cells and proton exchange membrane electrolyzers.

[0005] Therefore, there is a need for a bonding strength testing method that is closer to the actual application environment, easy to operate, and provides intuitive evaluation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an offline testing method for the binding force of proton exchange membranes or CCMs, thereby resolving the problems mentioned in the background section.

[0007] This invention is achieved through the following technical solution: an offline testing method for the binding force of proton exchange membranes or CCMs, comprising the following steps:

[0008] Step 1: Provide the proton exchange membrane sample or CCM sample to be tested;

[0009] Step 2: Take a high-pressure vessel with a pressure resistance of ≥6MPa, add ultrapure water to it, and add water in a predetermined proportion of the effective volume of the high-pressure vessel. The predetermined proportion is the amount of water that can ensure that the sample is subjected to sufficient bubble impact during the depressurization process.

[0010] Step 3: Immerse the sample to be tested completely or partially in the ultrapure water in the high-pressure tank, or fix the sample above the water surface but ensure that the air bubbles generated during depressurization can fully act on the sample surface;

[0011] Step 4: Seal the high-pressure tank, install a pressure transmitter inside the container, and introduce gas into the high-pressure tank through the gas cylinder via the air inlet to pressurize it. Add a first solenoid valve to the air inlet path to make the pressure inside the high-pressure tank reach the preset test pressure value.

[0012] Step 5: Hold the pressure at the preset test pressure for a predetermined time, then open the second solenoid valve located at the exhaust port of the high-pressure tank to quickly release the pressure in the high-pressure tank to atmospheric pressure. During the pressure release process, a large number of bubbles are released instantly in the ultrapure water due to the sudden drop in pressure.

[0013] Step 6: After depressurization, remove the sample to be tested, observe the sample surface and cross-section, check whether the proton exchange membrane has delamination, and whether the catalyst layer in the CCM has peeled off, flaked or cracked from the surface of the proton exchange membrane.

[0014] Step 7: Evaluate the interlayer bonding force or the bonding force between the catalyst layer and the proton exchange membrane based on the observation results.

[0015] As a preferred embodiment, the preset test pressure value ranges from 1 MPa to 5 MPa.

[0016] In a preferred embodiment, the pressure holding time is 3 to 5 minutes.

[0017] In a preferred embodiment, the first solenoid valve and the second solenoid valve are controlled independently or work in coordination through program control.

[0018] As a preferred embodiment, the sample observation in step six is ​​performed by visual observation, optical microscopy, or electron microscopy.

[0019] As a preferred embodiment, the pressurization-depressurization cycle test of steps one through six is ​​repeated multiple times to examine the bonding stability of the sample under multiple impacts.

[0020] In a preferred embodiment, the gas cylinder is a nitrogen cylinder or an air cylinder.

[0021] In a preferred embodiment, the pressure relief rate of the high-pressure tank is controlled within the range of 0.5-5 seconds / MPa by the opening degree of the second solenoid valve.

[0022] After adopting the above technical solution, the beneficial effects of the present invention are: 1. Strong simulation: The large number of bubbles generated by high pressure relief impact the membrane sample or CCM sample, which can simulate the impact force of gas on the proton exchange membrane layer or the catalyst layer and membrane interface during the operation of the PEM electrolyzer, especially under the conditions of start-up, shutdown, and load change, making the test results more valuable.

[0023] 2. Easy to operate: The testing device is relatively simple, mainly consisting of a high-pressure tank, gas cylinder, solenoid valve and pressure gauge, etc. The sample preparation and testing process is convenient and easy to implement.

[0024] 3. Intuitive evaluation: The binding force can be qualitatively or semi-quantitatively evaluated by directly observing whether the sample delamination or catalyst layer detachment occurs, and the results are intuitive and easy to understand.

[0025] 4. Good controllability: The bonding strength of samples under different impact intensities can be evaluated by adjusting parameters such as test pressure, holding time, depressurization rate and number of cycles.

[0026] 5. Wide applicability: Applicable to the binding force testing of various types of proton exchange membranes and CCMs. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of an offline testing device for the bonding force of a proton exchange membrane or CCM according to the present invention.

[0029] Figure 2 This is a flowchart of the offline testing method for the binding force of a proton exchange membrane or CCM according to the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] As the first embodiment of the present invention:

[0032] Please see Figures 1 to 2 An offline testing method for the binding force of proton exchange membranes or CCMs includes the following steps:

[0033] Step 1: Provide the proton exchange membrane sample or CCM sample to be tested;

[0034] Step 2: Take a high-pressure vessel with a pressure resistance of ≥6MPa, add ultrapure water to it, and add water in a predetermined proportion of the effective volume of the high-pressure vessel. The predetermined proportion is the amount of water that can ensure that the sample is fully impacted by air bubbles during the depressurization process.

[0035] Step 3: Immerse the sample to be tested completely or partially in the ultrapure water in the high-pressure tank, or fix the sample above the water surface but ensure that the air bubbles generated when the pressure is released can fully act on the sample surface;

[0036] Step 4: Seal the high-pressure tank, install a pressure transmitter inside the container, and introduce gas into the high-pressure tank through the gas cylinder via the air inlet to pressurize it. Add a first solenoid valve to the air inlet path to make the pressure inside the high-pressure tank reach the preset test pressure value.

[0037] Step 5: Hold the pressure at the preset test pressure for a predetermined time, then open the second solenoid valve located at the exhaust port of the high-pressure tank to quickly release the pressure in the high-pressure tank to atmospheric pressure. During the pressure release process, a large number of bubbles are released instantly in the ultrapure water due to the sudden drop in pressure.

[0038] Step 6: After depressurization, remove the sample to be tested, observe the sample surface and cross-section, check whether the proton exchange membrane has delamination, and whether the catalyst layer in the CCM has peeled off, flaked or cracked from the surface of the proton exchange membrane.

[0039] Step 7: Evaluate the interlayer bonding force or the bonding force between the catalyst layer and the proton exchange membrane based on the observation results.

[0040] The preset test pressure range is 1 MPa to 5 MPa.

[0041] The pressure holding time is set to 3 to 5 minutes.

[0042] The first and second solenoid valves can be controlled independently or work in tandem through program control.

[0043] In step six, sample observation is performed using visual observation, optical microscopy, or electron microscopy.

[0044] Repeat steps one through six of the pressurization-depressurization cycle test multiple times to examine the bonding stability of the sample under multiple impacts.

[0045] The gas cylinder is either a nitrogen cylinder or an air cylinder.

[0046] The pressure relief rate of the high-pressure tank is controlled within the range of 0.5-5 seconds / MPa by the opening degree of the second solenoid valve.

[0047] Specific implementation steps;

[0048] Step 1: Sample preparation: Cut a CCM sample with an area of ​​approximately 5cm × 5cm.

[0049] Step 2: Take a high-pressure vessel with an effective volume of 1L, add 500mL of ultrapure water into it, and immerse the CCM sample from Step 1 in the ultrapure water.

[0050] Step 3: Seal the high-pressure tank, connect the nitrogen cylinder through the air inlet, open the first solenoid valve, fill the tank with nitrogen, pressurize to 2.0 MPa, and maintain the pressure for 3 minutes.

[0051] Step 4: Close the first solenoid valve, and then quickly open the second solenoid valve located at the exhaust port to release the pressure inside the tank to normal pressure within 10 seconds. Observe that a large number of bubbles are generated in the water and it is violently churning.

[0052] Step 5: Take out the CCM sample, gently rinse the surface moisture with deionized water, observe visually and observe with an optical microscope (100x). The results show that the catalyst layer of the CCM sample has no obvious peeling, flaking or cracking, and the proton exchange membrane has no delamination, indicating that its binding force is good.

[0053] The entire method uses a large number of bubbles generated by high-pressure depressurization to impact the membrane sample or CCM sample. This can simulate, to a certain extent, the impact force of gases (such as hydrogen, oxygen, nitrogen, or bubbles generated by the condensation and re-evaporation of water vapor) on the interlayer of the proton exchange membrane or the interface between the catalyst layer and the membrane during the operation of a PEM electrolyzer, especially under conditions such as start-up, shutdown, and load changes. This makes the test results more valuable. The test equipment for the entire method is relatively simple, mainly consisting of a high-pressure tank, gas cylinder, solenoid valve, and pressure gauge. Sample preparation and testing are convenient and easy to implement. By directly observing whether the sample delamination or catalyst layer detachment occurs, the binding force can be qualitatively or semi-quantitatively evaluated. The results are intuitive and easy to understand. By adjusting parameters such as test pressure, holding time, depressurization rate (controlled by solenoid valve), and number of cycles, the binding force of samples under different impact intensities can be evaluated. Its convenient operation is applicable to the binding force testing of various types of proton exchange membranes (including homogeneous membranes and composite membranes) and CCMs.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An offline testing method for the binding force of a proton exchange membrane or CCM, characterized in that, Includes the following steps: Step 1: Provide the proton exchange membrane sample or CCM sample to be tested; Step 2: Take a high-pressure vessel with a pressure resistance of ≥6MPa, add ultrapure water to it, and add water in a predetermined proportion of the effective volume of the high-pressure vessel. The predetermined proportion is the amount of water that can ensure that the sample is subjected to sufficient bubble impact during the depressurization process. Step 3: Immerse the sample to be tested completely or partially in the ultrapure water in the high-pressure tank, or fix the sample above the water surface but ensure that the air bubbles generated during depressurization can fully act on the sample surface; Step 4: Seal the high-pressure tank, install a pressure transmitter inside the container, and introduce gas into the high-pressure tank through the gas cylinder via the air inlet to pressurize it. Add a first solenoid valve to the air inlet path to make the pressure inside the high-pressure tank reach the preset test pressure value. Step 5: Hold the pressure at the preset test pressure for a predetermined time, then open the second solenoid valve located at the exhaust port of the high-pressure tank to quickly release the pressure in the high-pressure tank to atmospheric pressure. During the pressure release process, a large number of bubbles are released instantly in the ultrapure water due to the sudden drop in pressure. Step 6: After depressurization, remove the sample to be tested, observe the sample surface and cross-section, check whether the proton exchange membrane has delamination, and whether the catalyst layer in the CCM has peeled off, flaked or cracked from the surface of the proton exchange membrane. Step 7: Evaluate the interlayer bonding force or the bonding force between the catalyst layer and the proton exchange membrane based on the observation results.

2. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: The preset test pressure range is 1 MPa to 5 MPa.

3. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: The pressure holding time is 3 to 5 minutes.

4. The offline testing method for the bonding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: The first solenoid valve and the second solenoid valve can be controlled independently or work in coordination through program control.

5. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: In step six, sample observation is performed using visual observation, optical microscopy, or electron microscopy.

6. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: Repeat steps one through six of the pressurization-depressurization cycle test multiple times to examine the bonding stability of the sample under multiple impacts.

7. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: The gas cylinder is either a nitrogen cylinder or an air cylinder.

8. The offline testing method for the binding force of a proton exchange membrane or CCM as described in claim 1, characterized in that: The pressure relief rate of the high-pressure tank is controlled within the range of 0.5-5 seconds / MPa by the opening degree of the second solenoid valve.

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