Method for representing water absorption rate of proton exchange membrane material

Abstract

The invention provides a method for characterizing the water absorption rate of a proton exchange membrane material, a suspension system is used for testing, and the method comprises the following specific steps: step 1, weighing the mass of a fixed proton exchange membrane material, and recording the mass as m0; 2, fixing and drying the proton exchange membrane material; step 3, putting the fixed proton exchange membrane material into a weighing plate to ensure that the fixed proton exchange membrane material can be immersed by the liquid; and 4, connecting the electronic balance with the computer, recording an initial parameter as m1, recording the mass as m2 when the reading of the electronic balance is unchanged, and calculating the water absorption of the proton exchange membrane material by using the data. The water absorption capacity and the water absorption rate of the proton exchange membrane material can be tested in real time, and whether the proton exchange membrane material is saturated or not can be accurately judged.

Description

Technical Field

[0001] The present application relates to the field of fuel cell technology, and in particular to a method for characterizing the water absorption rate of a proton exchange membrane material. Background Art

[0002] Proton exchange membrane fuel cells (PEMFCs) have become an ideal energy source for electric vehicles, submarines, and various mobile devices due to their high specific power, high energy conversion efficiency, low-temperature start-up, corrosion-free, zero pollution, and environmentally friendly advantages. As one of the important components of PEMFC, the proton exchange membrane plays a key role in its performance. The core component of the fuel cell is the membrane electrode material, which is composed of a proton exchange membrane, a catalyst, and a gas diffusion layer through a hot pressing process. The proton exchange membrane is one of the core materials in the membrane electrode. The life of the membrane directly determines the service life of the fuel cell. In actual use, the dry and wet state of the proton exchange membrane directly affects its output performance and service life.

[0003] The water absorption standard for proton exchange membranes provides a more comprehensive understanding of the physical properties of membrane materials and allows them to more effectively utilize their physical properties. In fuel cells, water freezing not only affects reaction rates and hinders reactions, but also generates unbalanced stresses within the fuel cell. As the volume of ice decreases as it melts, the stresses gradually disappear. As the ice undergoes phase transitions, the repeated generation and disappearance of unbalanced stresses within the fuel cell will, to a certain extent, damage the structure and performance of the components, leading to degradation and a reduction in the fuel cell's lifespan. Studying the water absorption rate and rate of water absorption of the proton exchange membrane can determine whether an ice-free start can be achieved during a cold start. Understanding the water absorption rate of the proton exchange membrane is a prerequisite for a cold start. Therefore, it is crucial to clearly understand the water absorption rate of the proton exchange membrane and adopt appropriate strategies to improve the lifespan of the fuel cell. Therefore, developing methods to accurately test the water absorption rate of the proton exchange membrane is crucial. Summary of the Invention

[0004] The technical problem to be solved by the present application is that the traditional method for testing the water absorption rate of proton exchange membrane materials has large errors and cannot test the water absorption amount and water absorption rate of proton exchange membrane materials in real time.

[0005] To solve the above technical problems, the present disclosure provides a method for characterizing the water absorption rate of a proton exchange membrane material. The method uses a suspension system for testing, and the specific steps include: step 1, weighing the mass of the fixed proton exchange membrane material, recorded as m0; step 2, fixing and drying the proton exchange membrane material; step 3, placing the fixed proton exchange membrane material on a weighing pan to ensure that the fixed proton exchange membrane material can be immersed in liquid; step 4, connecting an electronic balance to a computer, recording the initial parameter as m1, and when the electronic balance reading remains unchanged, recording the mass as m2, and using the above data to calculate the water absorption rate of the proton exchange membrane material.

[0006] In some embodiments, the suspension system comprises: an electronic balance with a fixed support, a computer, a test liquid solvent, a density bracket, a weighing pan, and a container for holding the liquid;

[0007] The density bracket is inserted into the fixed bracket of the electronic balance, the weighing pan is connected to the density bracket, the container for holding the liquid is placed in the center below the density bracket, the test liquid solvent is injected into the container for holding the liquid, and the electronic balance is connected to the computer;

[0008] The test liquid solvent is ultrapure water.

[0009] The fixing bracket does not contact the density bracket.

[0010] In some embodiments, in step 2, the material for fixing the proton exchange membrane does not absorb water and its surface is wiped clean.

[0011] In some embodiments, the formula involved in calculating the water absorption rate of the proton exchange membrane in step 4 is: w=(m2-m1) / (m0)*100.

[0012] In some embodiments, in step 3, the amount of liquid added is sufficient to submerge the fixed proton exchange membrane material to a height greater than 1 cm, so as to ensure that the proton exchange membrane does not appear above the water surface during the water absorption process.

[0013] The method described in the present application can test the water absorption of the proton exchange membrane material in real time, can test and calculate the water absorption rate of the proton exchange membrane material in real time, and can accurately determine whether the proton exchange membrane material is saturated. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 This is a schematic diagram of the forces acting on the suspension system used to test the proton exchange membrane.

[0016] Figure 2 This is the electronic balance before modification.

[0017] Figure 3 It is a modified electronic balance. DETAILED DESCRIPTION

[0018] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The detailed description of the following examples and the accompanying drawings are intended to illustrate the principles of the present application, but are not intended to limit the scope of the present application. The present application may be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but rather includes all technical solutions within the scope of the claims.

[0019] The following describes in detail the hanging weighing system provided by the present disclosure and the method for characterizing the water absorption rate of the proton exchange membrane material.

[0020] The present disclosure provides a method for characterizing the water absorption rate of a proton exchange membrane material. The method utilizes a suspension system for testing, and the specific steps include: step 1, weighing the mass of the fixed proton exchange membrane material, which is recorded as m0; step 2, fixing and drying the proton exchange membrane material; step 3, placing the fixed proton exchange membrane material on a weighing pan to ensure that the fixed proton exchange membrane material is immersed in liquid; and step 4, connecting an electronic balance to a computer, recording an initial parameter as m1, and when the electronic balance reading remains unchanged, recording the mass as m2, and using the above data to calculate the water absorption rate of the proton exchange membrane material.

[0021] During the test process of this application, there is a time corresponding to when the initial parameter is recorded as m1, and a series of quality data corresponding to the time can be measured between m1 and m2. That is to say, the test method of this application can measure the water absorption rate and water absorption amount of the proton exchange membrane in real time.

[0022] In some embodiments, as Figure 1 As shown, Figure 1 is a schematic diagram of the test system disclosed herein, Figure 2 This is the electronic balance before modification. Figure 3 It is a modified electronic balance, and the suspension system includes: an electronic balance with a fixed bracket, a computer, a test liquid solvent, a density bracket, a weighing pan and a container for holding the liquid;

[0023] The density bracket is inserted into the fixed bracket of the electronic balance, the weighing pan is connected to the density bracket, the container for holding the liquid is placed in the center below the density bracket, the test liquid solvent is injected into the container for holding the liquid, and the electronic balance is connected to the computer;

[0024] The test liquid solvent is ultrapure water.

[0025] The suspension system test for measuring the water absorption of proton exchange membrane materials has the following advantages:

[0026] Efficient and accurate: A large amount of data can be obtained in a short time, improving test efficiency.

[0027] Non-destructive: The suspension system test is a non-destructive testing method that does not damage the proton exchange membrane. During the test, the proton exchange membrane material only needs to be suspended in the test equipment, without any modification or treatment of the membrane.

[0028] High Accuracy: The suspension system test provides highly accurate water absorption data. Utilizing advanced measurement equipment and technology, this test method accurately measures the rate and capacity of water absorption by the proton exchange membrane material, providing reliable data reference.

[0029] Good repeatability: The test results of the suspension system have good repeatability. Through multiple tests, similar or consistent water absorption data can be obtained, increasing the credibility of the test results.

[0030] Wide Range of Applications: The suspension system test is applicable to various types of proton exchange membrane materials. Whether used in fuel cells, water electrolysis to produce hydrogen, or other fields, the suspension system test can be used to evaluate the water absorption performance of proton exchange membranes.

[0031] Traditional methods require the membrane to be completely immersed in water for a certain period of time to achieve water absorption equilibrium. This process may take several hours or days, with a long measurement cycle, and requires the preparation of a large number of experimental samples and reagents, and the operation process is cumbersome. For example, the weight of the membrane and water needs to be accurately weighed, and the membrane needs to be completely immersed in water. The membrane must also be removed regularly and excess water on the surface must be removed. The measurement error in traditional methods is large and may be affected by external environmental factors such as temperature and humidity. These factors may lead to inaccurate measurement results. Traditional methods can only measure at specific time points and cannot monitor changes in the water absorption properties of the membrane in real time. This is not convenient for some applications that require continuous monitoring of water absorption properties.

[0032] The principle of measuring the water absorption rate of the proton exchange membrane material using water in the suspension system in this application is to use the adsorption and permeation properties of water in the proton exchange membrane for measurement. The proton exchange membrane is a material with a special structure that can transport ions through proton exchange.

[0033] During the measurement, the proton exchange membrane is first suspended under certain conditions, usually on a water-permeable support. Then, a container filled with a certain amount of water is placed under the proton exchange membrane, allowing the water to freely penetrate the membrane.

[0034] As time goes by, water will enter the proton exchange membrane through osmosis. The water absorption rate of the proton exchange membrane can be calculated from the value measured by the balance.

[0035] In some embodiments, in step 2, the material for fixing the proton exchange membrane does not absorb water and its surface is wiped clean. The material for fixing the proton exchange membrane does not absorb water and does not react in water, nor does it absorb water, in order to avoid measurement errors.

[0036] In some embodiments, the formula involved in calculating the water absorption rate of the proton exchange membrane material in step 4 is:

[0037] w=(m2-m1) / (m0)*100.

[0038] like Figure 1 As shown, after force analysis, we know that: M g =F N +F 浮 , F N =m 物体 ×gg×V 物体 ×ρ 溶剂

[0039] Buoyancy has nothing to do with the mass of an object. Therefore, the buoyancy of an object in water is the same. When calculating the mass of water absorbed by a substance, you only need to read the readings on the balance before and after absorbing water and subtract them to get the mass of water absorbed.

[0040] In some embodiments, in step three, the amount of liquid added is sufficient to submerge the fixed proton exchange membrane material to a height greater than 1 cm.

[0041] The method described in the present application can test the water absorption of the proton exchange membrane material in real time, can test and calculate the water absorption rate of the proton exchange membrane in real time, and can accurately determine whether the proton exchange membrane material is saturated.

[0042] Example

[0043] Embodiment 1:

[0044] Water absorption test of proton exchange membrane materials using a suspension system:

[0045] Step 1: weigh the mass of the proton exchange membrane material in the air, recorded as m0;

[0046] Step 2: Fix and dry the proton exchange membrane material, where the fixing material is iron wire;

[0047] Step 3: placing the fixed proton exchange membrane material on the weighing plate of the fixed bracket to ensure that the fixed proton exchange membrane material can be immersed in the liquid;

[0048] Step 4: Use a data cable to connect the balance and notebook, record the initial parameter as m1, and when the balance reading remains unchanged, record the mass as m2. Use the above data to calculate the water absorption rate of the proton exchange membrane.

[0049] The mass m0 of the proton exchange membrane was tested to be 43.14 mg. Some test data recorded by the suspension system are shown in Table 1.

[0050]

[0051] Comparative Example 1:

[0052] Using the traditional test method, to ensure that the proton exchange membrane is saturated with water, the mass m of the dry proton exchange membrane is weighed on a balance. The proton exchange membrane is placed in water to absorb water for 4 hours, and the mass m of the proton exchange membrane after saturation is weighed on a balance. n , through the formula (m n The water absorption rate of the proton exchange membrane was calculated by averaging 100 μm (-m) / m. The test was repeated three times.

[0053] Table 2 Test data of traditional method

[0054]

[0055] It can be seen from the above data that the data in Table 1 is only part of the data tested in this application. The testing method of this application can measure the water absorption and water absorption rate of the proton exchange membrane material in real time, and can accurately determine the saturation point of the proton exchange membrane material. From the data of Example 1, it can be seen that the traditional method has a large error. Even if the same proton exchange membrane is tested, the error of the data is relatively large. It cannot be tested in real time and the real-time water absorption of the proton exchange membrane cannot be obtained, and the saturation point of the proton exchange membrane material cannot be accurately determined.

[0056] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art will understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present application. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. In particular, as long as there are no structural conflicts, the various technical features mentioned in the various embodiments may be combined in any manner.

Claims

1. A method for characterizing the water absorption rate of a proton exchange membrane material, characterized in that: The specific steps of testing using a suspension system include: Step 1, weigh the mass of the fixed proton exchange membrane material, recorded as m0; Step 2, fixing and drying the proton exchange membrane material; Step 3, placing the fixed proton exchange membrane material in a weighing pan, ensuring that the fixed proton exchange membrane material can be immersed in the liquid; Step 4: Connect the electronic balance to the computer and record the initial parameter as m1. When the electronic balance reading remains unchanged, the mass is recorded as m2. The water absorption rate of the proton exchange membrane material is calculated using the above data.

2. The method for characterizing the water absorption rate of a proton exchange membrane material according to claim 1, characterized in that: The suspension system comprises: an electronic balance with a fixed support, a computer, a test liquid solvent, a density bracket, a weighing pan and a container for containing liquid; The density bracket is inserted into the fixed bracket of the electronic balance, the weighing pan is connected to the density bracket, the container containing the liquid is placed in the central position below the density bracket, the test liquid solvent is injected into the container containing the liquid, and the electronic balance is connected to the computer; The test liquid solvent is ultrapure water.

3. The method for characterizing the water absorption rate of a proton exchange membrane material according to claim 1, characterized in that: In step 2, the material for fixing the proton exchange membrane does not absorb water and the surface is wiped clean.

4. The method for characterizing the water absorption rate of a proton exchange membrane material according to claim 1, characterized in that: The formula involved in calculating the water absorption rate of the proton exchange membrane in step 4 is: w=(m2-m1) / (m0)*100.

5. The method for characterizing the water absorption rate of a proton exchange membrane material according to claim 1, characterized in that: In step three, the amount of liquid added is sufficient to immerse the fixed proton exchange membrane material to a height of more than 1 cm.

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