Method and system for testing resistance of bipolar plate of fuel cell and storage medium

Abstract

The invention provides a fuel cell bipolar plate resistance testing method and system and a storage medium, and the method comprises the steps: obtaining a to-be-tested bipolar plate; performing a pressure test on the bipolar plate to be tested based on a preset pressure gradient to obtain a mixed impedance value of the bipolar plate to be tested; establishing a hybrid resistance function based on a preset pressure gradient and the hybrid impedance value of the bipolar plate to be measured; performing nonlinear fitting on the mixed resistance function, and solving the resistance value of the bipolar plate body to be measured; and based on the mixed impedance value of the bipolar plate to be tested and the body resistance value of the bipolar plate to be tested, obtaining the contact resistance value of the bipolar plate to be tested, thereby realizing the test of the resistance of the bipolar plate of the fuel cell. According to the fuel cell bipolar plate resistance testing method and system and the storage medium provided by the invention, accurate separation of the fuel cell bipolar plate body resistance and the contact resistance can be realized.

Description

Technical Field

[0001] This invention relates to the field of fuel cell performance testing technology, and in particular to a method, system, and storage medium for testing the bipolar plate resistance of a fuel cell. Background Technology

[0002] Currently, the testing methods for fuel cell-related resistances are mainly divided into three categories: First, the surface resistance test of the bipolar plate, which is usually achieved using the 4-probe method; second, the mixed resistance test of contact resistance and bulk resistance, where the mixed resistance specifically refers to the superposition value of the contact resistance (R1+R3) between the contact block and the bipolar plate and the bulk resistance (R2) of the bipolar plate itself, which is generally completed using a resistance meter; and third, the ohmic resistance test of the fuel cell stack, which covers the contact resistance between the GDL (gas diffusion layer) and the bipolar plate, the contact resistance between the GDL and the CCM (catalytic coating membrane), and the bulk resistance of the GDL, bipolar plate, and CCM, which is usually tested using a high-frequency impedance meter.

[0003] Please refer to the existing technology context. Figure 1 The upper and lower contact blocks of the resistance meter are rigid and incompressible, while the bipolar plate under test is compressible. The upper contact block (usually a gold-plated copper block) of the resistance meter is brought into contact with the bipolar plate under test, and the lower contact block (also usually a gold-plated copper block) is brought into contact with the bipolar plate under test. In other words, the two contact blocks of the resistance meter clamp the bipolar plate under test for measurement. The obtained resistance is the sum of the contact resistance between the test block and the bipolar plate and the resistance of the bipolar plate itself (i.e., R = R1 + R2 + R3, where R1 is the contact resistance between the upper contact block of the resistance meter and the bipolar plate, R2 is the resistance of the bipolar plate under test, and R3 is the contact resistance between the lower contact block of the resistance meter and the bipolar plate). The resistance is measured as a constant value, independent of the test pressure. The contact resistance between the upper contact block and the bipolar plate, and the contact resistance between the lower contact block and the bipolar plate, is the sum of the contact resistances of the upper and lower contact blocks of the impedance meter. This contact resistance is related to the test pressure and is not simply the volume resistance of the bipolar plate (it cannot be isolated). Furthermore, the industry currently lacks technologies and methods to independently test the volume resistance of bipolar plates or other fuel cell stack components, or to effectively decompose the mixed resistances measured by the impedance meter. This technological gap has caused difficulties for engineers, especially in research and development aimed at improving fuel cell stack performance by reducing the volume resistance of bipolar plates (particularly graphite bipolar plates). The inability to accurately obtain volume resistance data leads to a lack of clear technical basis for related optimization directions, significantly hindering the research and development process for improving fuel cell stack performance. Summary of the Invention

[0004] The present invention aims to provide a method, system and storage medium for testing the resistance of bipolar plates in fuel cells, so as to solve the above-mentioned technical problems and achieve accurate separation of the body resistance and contact resistance of fuel cell bipolar plates.

[0005] To address the aforementioned technical problems, this invention provides a method for testing the bipolar plate resistance of a fuel cell, comprising:

[0006] Obtain the bipolar plate to be tested;

[0007] A pressure test is performed on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test.

[0008] A hybrid resistance function is established based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test.

[0009] The mixed resistance function is nonlinearly fitted to solve for the resistance value of the bipolar plate to be measured;

[0010] Based on the mixed impedance value of the bipolar plate under test and the bulk resistance value of the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0011] In the above scheme, a preset pressure gradient is used to gradually apply pressure to the bipolar plate under test, and impedance data is collected at each pressure point to obtain the mixed impedance value of the bipolar plate under test, providing basic data support for establishing the mixed resistance function. Next, the mathematical relationship between resistance and pressure is clarified through the mixed resistance function, laying the model foundation for subsequent volume resistance calculation. Subsequently, by performing nonlinear fitting on the mixed resistance function, the volume resistance in the mixed impedance value of the bipolar plate under test is separated, obtaining the volume resistance value of the bipolar plate under test. Finally, using the relationship between the mixed impedance value and the volume resistance value of the bipolar plate under test, the contact resistance value of the bipolar plate under test is calculated, achieving accurate separation of the volume resistance and contact resistance of the fuel cell bipolar plate.

[0012] Furthermore, the acquisition of the bipolar plate under test includes:

[0013] Obtain the original bipolar plate under test;

[0014] The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

[0015] In the above scheme, the original bipolar plate to be tested is pre-processed to avoid affecting the contact state between the bipolar plate and the test block. At the same time, the size of the bipolar plate is verified to ensure that the test block can completely cover the test area of ​​the bipolar plate during the test, thereby eliminating test errors and obtaining a bipolar plate to be tested that meets the test standards.

[0016] Further, the step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes:

[0017] There are several bipolar plates to be tested;

[0018] A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test.

[0019] Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test.

[0020] The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

[0021] In the above scheme, several identical bipolar plates under test are prepared to provide test samples with the same properties for subsequent single-plate and multi-plate stacked tests, avoiding test data deviations caused by individual differences in bipolar plates and ensuring the comparability of the two test data and the accuracy of subsequent calculations. Next, by selecting any one of the bipolar plates and applying pressure according to a preset pressure gradient, the mixed impedance value of a single bipolar plate under different pressures is obtained, providing basic single-plate data for subsequent comparison calculations with multi-plate mixed impedance values. Subsequently, by applying pressure to several bipolar plates under test with the same preset pressure gradient as the single-plate test, the mixed impedance values ​​of multi-plate stacked bipolar plates under different pressures are obtained, constructing basic data for multi-plate testing and providing multi-plate data support for subsequent difference calculations. Finally, the difference between the multi-plate mixed impedance value and the single-plate mixed impedance value is calculated, and the difference data is used as the optimized mixed impedance value of the bipolar plate under test, amplifying the signals of body resistance and contact resistance, diluting random errors in single-plate testing, and improving the accuracy of subsequent mixed resistance function fitting and resistance separation.

[0022] Further, the step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes:

[0023] Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient.

[0024] Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

[0025] In the above scheme, the bipolar plate under test is gradually pressurized by combining a preset pressure gradient and a preset pressure time to ensure that the pressure and resistance values ​​are sufficiently stable at each pressure point, avoiding impedance data fluctuations caused by unstable pressure. This allows for the acquisition of stable and reliable mixed impedance values ​​corresponding to each pressure gradient point, providing high-quality data support for subsequent data processing.

[0026] Furthermore, the step of obtaining the contact resistance value of the bipolar plate based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell; specifically:

[0027] Based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, the initial contact resistance value of the bipolar plate under test is obtained.

[0028] Obtain the contact area of ​​the bipolar plate under test;

[0029] Based on the initial contact resistance value and contact area of ​​the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0030] In the above scheme, the core relationship of "mixed resistance = volume resistance + contact resistance" is used to directly separate the initial contact resistance value corresponding to each pressure point, thus achieving preliminary extraction of the contact resistance. Subsequently, the initial contact resistance value is converted proportionally to obtain the contact resistance value that conforms to the actual use scenario of the bipolar plate, thereby achieving accurate testing of the volume resistance and contact resistance of the fuel cell bipolar plate.

[0031] This invention provides a testing system for the bipolar plate resistance of a fuel cell, comprising a bipolar plate acquisition module, a pressure testing module, a function establishment module, a volume resistance calculation module, and a contact resistance calculation module, specifically:

[0032] The bipolar plate acquisition module is used to acquire the bipolar plate to be tested;

[0033] The pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test.

[0034] The function establishment module is used to establish a hybrid resistance function based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test;

[0035] The bulk resistance calculation module is used to perform nonlinear fitting on the hybrid resistance function to solve for the bulk resistance value of the bipolar plate to be measured.

[0036] The contact resistance calculation module is used to obtain the contact resistance value of the bipolar plate under test based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0037] This invention provides a testing system for the resistance of a fuel cell bipolar plate. In practical applications, only a pressure testing module is needed. A preset pressure gradient is applied to the bipolar plate under test, and impedance data is collected at each pressure point to obtain the mixed impedance value of the bipolar plate, providing basic data support for establishing the mixed resistance function. Next, a function establishment module is used to clarify the mathematical relationship between resistance and pressure through the mixed resistance function, laying the model foundation for subsequent volume resistance calculation. Then, a volume resistance calculation module is used to separate the volume resistance from the mixed impedance value of the bipolar plate under test by performing nonlinear fitting on the mixed resistance function, obtaining the volume resistance value of the bipolar plate under test. Finally, a contact resistance calculation module is used to calculate the contact resistance value of the bipolar plate under test by utilizing the relationship between the mixed impedance value and the volume resistance value, achieving accurate separation of the volume resistance and contact resistance of the fuel cell bipolar plate.

[0038] Furthermore, the bipolar plate acquisition module is used to acquire the bipolar plate to be tested; including:

[0039] Obtain the original bipolar plate under test;

[0040] The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

[0041] In the above scheme, the original bipolar plate to be tested is pre-processed to avoid affecting the contact state between the bipolar plate and the test block. At the same time, the size of the bipolar plate is verified to ensure that the test block can completely cover the test area of ​​the bipolar plate during the test, thereby eliminating test errors and obtaining a bipolar plate to be tested that meets the test standards.

[0042] Furthermore, the pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including:

[0043] There are several bipolar plates to be tested;

[0044] A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test.

[0045] Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test.

[0046] The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

[0047] In the above scheme, several identical bipolar plates under test are prepared to provide test samples with the same properties for subsequent single-plate and multi-plate stacked tests, avoiding test data deviations caused by individual differences in bipolar plates and ensuring the comparability of the two test data and the accuracy of subsequent calculations. Next, by selecting any one of the bipolar plates and applying pressure according to a preset pressure gradient, the mixed impedance value of a single bipolar plate under different pressures is obtained, providing basic single-plate data for subsequent comparison calculations with multi-plate mixed impedance values. Subsequently, by applying pressure to several bipolar plates under test with the same preset pressure gradient as the single-plate test, the mixed impedance values ​​of multi-plate stacked bipolar plates under different pressures are obtained, constructing basic data for multi-plate testing and providing multi-plate data support for subsequent difference calculations. Finally, the difference between the multi-plate mixed impedance value and the single-plate mixed impedance value is calculated, and the difference data is used as the optimized mixed impedance value of the bipolar plate under test, amplifying the signals of body resistance and contact resistance, diluting random errors in single-plate testing, and improving the accuracy of subsequent mixed resistance function fitting and resistance separation.

[0048] Furthermore, the pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including:

[0049] Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient.

[0050] Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

[0051] In the above scheme, the bipolar plate under test is gradually pressurized by combining a preset pressure gradient and a preset pressure time to ensure that the pressure and resistance values ​​are sufficiently stable at each pressure point, avoiding impedance data fluctuations caused by unstable pressure. This allows for the acquisition of stable and reliable mixed impedance values ​​corresponding to each pressure gradient point, providing high-quality data support for subsequent data processing.

[0052] The present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the functions of the system as described above. Attached Figure Description

[0053] Figure 1 This invention provides a prior art method for testing the bipolar plate resistance of a fuel cell, as an embodiment of the present invention.

[0054] Figure 2 A flowchart illustrating a method for testing the bipolar plate resistance of a fuel cell according to an embodiment of the present invention;

[0055] Figure 3 This is an architectural diagram of a fuel cell bipolar plate resistance testing system provided in an embodiment of the present invention;

[0056] Figure 4 A 25cm [material] provided in one embodiment of the present invention 2 A comparison chart of the fitted resistance of the molded graphite plate and the measured value;

[0057] Figure 5 A 25cm [material] provided in one embodiment of the present invention 2 A comparison chart of the fitted resistance of the engraved graphite plate and the measured value. Detailed Implementation

[0058] 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.

[0059] This embodiment provides a method for testing the bipolar plate resistance of a fuel cell; please refer to the flowchart for details. Figure 2 ,include:

[0060] Obtain the bipolar plate to be tested;

[0061] A pressure test is performed on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test.

[0062] A hybrid resistance function is established based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test.

[0063] The mixed resistance function is nonlinearly fitted to solve for the resistance value of the bipolar plate to be measured;

[0064] Based on the mixed impedance value of the bipolar plate under test and the bulk resistance value of the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0065] In this embodiment, a preset pressure gradient is used to gradually apply pressure to the bipolar plate under test, and impedance data is collected at each pressure point to obtain the mixed impedance value of the bipolar plate under test, providing basic data support for establishing the mixed resistance function. The preset pressure gradient typically refers to five or more gradients, and the pressure range is typically 0 N / cm². 2 -150N / cm 2 In this embodiment, the pressure range of the preset pressure gradient is selected as 0-135 N / cm. 2The preset pressure gradient selected 20 points, with a pressure difference of 6.75 / cm between any two adjacent pressure test points. 2 Next, by using a hybrid resistance function, the mathematical relationship between resistance and pressure was clarified, laying the model foundation for subsequent calculations of volume resistance. Hybrid Resistance Function Where X represents the pressure value, R represents the mixed impedance value of the bipolar plate under test, R0 represents the bulk resistance value of the bipolar plate under test, A0 is the contact resistance pressure coefficient, which is related to the material and surface characteristics of the bipolar plate under test, and K is the contact resistance coefficient, which is related to the structure of the bipolar plate under test, such as porosity and surface roughness. Subsequently, by performing nonlinear fitting on the mixed resistance function, the bulk resistance in the mixed impedance value of the bipolar plate under test is separated, yielding the bulk resistance value of the bipolar plate under test. The values ​​of R and R0 can be obtained by limiting X, i.e., when X is infinite, or by solving for the intersection of the tangent line and the ordinate of the last pressure point of the simulated curve of the mixed resistance function. Finally, using the relationship between the mixed impedance value and the bulk resistance value of the bipolar plate under test, the contact resistance value of the bipolar plate under test is calculated, achieving accurate separation of the bulk resistance and contact resistance of the fuel cell bipolar plate.

[0066] Furthermore, the acquisition of the bipolar plate under test includes:

[0067] Obtain the original bipolar plate under test;

[0068] The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

[0069] In this embodiment, the original bipolar plate to be tested is preprocessed to avoid affecting the contact state between the bipolar plate and the test block. At the same time, the size of the bipolar plate is verified to ensure that the test block can completely cover the test area of ​​the bipolar plate during the test, thereby eliminating test errors and obtaining a bipolar plate to be tested that meets the test standards.

[0070] Further, the step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes:

[0071] There are several bipolar plates to be tested;

[0072] A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test.

[0073] Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test.

[0074] The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

[0075] In this embodiment, several identical bipolar plates to be tested are prepared, each with a length of L and a width of h. The contact block of the resistance meter has a length of L' and a width of h', where L>L' and h>h'. This provides test samples with the same properties for subsequent single-plate testing and multi-plate stacking testing, avoiding test data deviations caused by individual differences in bipolar plates and ensuring the comparability of the two test data and the accuracy of subsequent calculations. Then, n identical bipolar plates to be tested are stacked at the center of the resistance meter contact block, and pressure is applied to these n bipolar plates to measure the mixed impedance value R of the multiple bipolar plates to be tested. n = 2*R1 + (n-1)*R2 + n*R0, where R1 is the contact resistance between the resistor contact block and the bipolar plate under test, R2 is the contact resistance between the bipolar plates under test, and R0 is the bulk resistance of the bipolar plate under test. Next, by selecting any one of several bipolar plates and applying pressure according to a preset pressure gradient, the mixed impedance value of a single bipolar plate under different pressures is obtained, and the mixed impedance value R of the bipolar plate under test is... singel = 2*R1+R3, where R3 is the bulk resistance of the bipolar plate under test, providing basic data for the subsequent comparison calculation of mixed impedance values ​​of multiple plates. Subsequently, by applying pressure to several bipolar plates with the same preset pressure gradient as the single bipolar plate under test, the mixed impedance values ​​of multiple bipolar plates under test are obtained, constructing the basic data for multi-plate testing, and providing multi-plate data support for subsequent difference calculations. Finally, the difference between the mixed impedance values ​​of multiple bipolar plates and the mixed impedance values ​​of a single bipolar plate is calculated, which is the contact resistance of n-1 bipolar plates under test and the bulk resistance of n-1 bipolar plates under test, (n-1)R2+(n-1)R0. The difference data is used as the optimized mixed impedance value of the bipolar plate under test, which amplifies the signals of bulk resistance and contact resistance. Since the bulk resistance R0 of the bipolar plate under test is increased by (n-1) times, and the contact resistance R2 is also increased by (n-1) times, the overall test accuracy will be greatly improved and the random error in the single-plate test will be diluted, thus improving the accuracy of subsequent mixed resistance function fitting and resistance separation.

[0076] Further, the step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes:

[0077] Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient.

[0078] Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

[0079] In this embodiment, the bipolar plate under test is gradually pressurized by combining a preset pressure gradient and a preset pressure time. The preset pressure time can be 30s-120s. In this embodiment, the average value measured by the resistance meter within 30-60s after reaching the specified pressure can be taken as the mixed impedance value of the bipolar plate under test. This ensures that the pressure and resistance values ​​are sufficiently stable at each pressure point, avoiding impedance data fluctuations caused by unstable pressure. This allows for the acquisition of stable and reliable mixed impedance values ​​corresponding to each pressure gradient point, providing high-quality data support for subsequent data processing.

[0080] Furthermore, the step of obtaining the contact resistance value of the bipolar plate based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell; specifically:

[0081] Based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, the initial contact resistance value of the bipolar plate under test is obtained.

[0082] Obtain the contact area of ​​the bipolar plate under test;

[0083] Based on the initial contact resistance value and contact area of ​​the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0084] In this embodiment, the core relationship of "mixed resistance = volume resistance + contact resistance" is utilized to directly separate the initial contact resistance value corresponding to each pressure point, achieving preliminary extraction of the contact resistance. Subsequently, the initial contact resistance value is converted proportionally. Since the contact area and pressure X typically exhibit an exponential relationship in engineering, while the contact resistance and contact area are reciprocally related, i.e., R... ′ ~1 / S, and the final actual measured bipolar plate resistance value is R. ′ =R0*B / S. Where B is the area of ​​the bipolar plate under test. Therefore, for the mixed impedance value of the bipolar plate under test obtained by the resistance meter, The contact resistance pressure coefficient A0 is less than 0 and is negative. This yields a contact resistance value that conforms to the actual application scenario of the bipolar plate, thereby enabling accurate testing of the bipolar plate's bulk resistance and contact resistance in fuel cells.

[0085] Please see Figure 3 This embodiment provides a testing system for the bipolar plate resistance of a fuel cell, including a bipolar plate acquisition module, a pressure testing module, a function establishment module, a volume resistance solving module, and a contact resistance solving module, specifically:

[0086] The bipolar plate acquisition module is used to acquire the bipolar plate to be tested;

[0087] The pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test.

[0088] The function establishment module is used to establish a hybrid resistance function based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test;

[0089] The bulk resistance calculation module is used to perform nonlinear fitting on the hybrid resistance function to solve for the bulk resistance value of the bipolar plate to be measured.

[0090] The contact resistance calculation module is used to obtain the contact resistance value of the bipolar plate under test based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell.

[0091] This embodiment provides a fuel cell bipolar plate resistance testing system. In practical applications, only a pressure testing module is needed. A preset pressure gradient is applied to the bipolar plate under test step by step, and impedance data is collected at each pressure point to obtain the mixed impedance value of the bipolar plate under test, providing basic data support for establishing the mixed resistance function. The preset pressure gradient typically refers to five or more gradients, and the pressure range is typically 0 N / cm². 2 -150N / cm 2 In this embodiment, the pressure range of the preset pressure gradient is selected as 0-135 N / cm. 2 The preset pressure gradient selected 20 points, with a pressure difference of 6.75 / cm between any two adjacent pressure test points. 2 Next, a function-based module was used to clarify the mathematical relationship between resistance and pressure through a hybrid resistance function, laying the model foundation for subsequent calculations of volume resistance. Hybrid Resistance Function Where X represents the pressure value, R represents the mixed impedance value of the bipolar plate under test, R0 represents the bulk resistance value of the bipolar plate under test, A0 is the contact resistance pressure coefficient, which is related to the material and surface characteristics of the bipolar plate under test, and K is the contact resistance coefficient, which is related to the structure of the bipolar plate under test, such as the porosity and surface roughness. Subsequently, a bulk resistance calculation module is used to separate the bulk resistance from the mixed impedance value of the bipolar plate under test by performing nonlinear fitting on the mixed resistance function, thus obtaining the bulk resistance value of the bipolar plate under test. The values ​​of R and R0 can be obtained by taking the limit of X, i.e., when X is infinite, or by solving for the intersection of the tangent line and the ordinate of the last pressure point of the simulated curve of the mixed resistance function. Finally, a contact resistance calculation module is used to calculate the contact resistance value of the bipolar plate under test by utilizing the relationship between the mixed impedance value and the bulk resistance value of the bipolar plate under test, achieving accurate separation of the bulk resistance and contact resistance of the fuel cell bipolar plate.

[0092] Furthermore, the bipolar plate acquisition module is used to acquire the bipolar plate to be tested; including:

[0093] Obtain the original bipolar plate under test;

[0094] The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

[0095] In this embodiment, the original bipolar plate to be tested is preprocessed to avoid affecting the contact state between the bipolar plate and the test block. At the same time, the size of the bipolar plate is verified to ensure that the test block can completely cover the test area of ​​the bipolar plate during the test, thereby eliminating test errors and obtaining a bipolar plate to be tested that meets the test standards.

[0096] Furthermore, the pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including:

[0097] There are several bipolar plates to be tested;

[0098] A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test.

[0099] Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test.

[0100] The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

[0101] In this embodiment, several identical bipolar plates to be tested are prepared, each with a length of L and a width of h. The contact block of the resistance meter has a length of L' and a width of h', where L>L' and h>h'. This provides test samples with the same properties for subsequent single-plate testing and multi-plate stacking testing, avoiding test data deviations caused by individual differences in bipolar plates and ensuring the comparability of the two test data and the accuracy of subsequent calculations. Then, n identical bipolar plates to be tested are stacked at the center of the resistance meter contact block, and pressure is applied to these n bipolar plates to measure the mixed impedance value R of the multiple bipolar plates to be tested. n = 2*R1 + (n-1)*R2 + n*R0, where R1 is the contact resistance between the resistor contact block and the bipolar plate under test, R2 is the contact resistance between the bipolar plates under test, and R0 is the bulk resistance of the bipolar plate under test. Next, by selecting any one of several bipolar plates and applying pressure according to a preset pressure gradient, the mixed impedance value of a single bipolar plate under different pressures is obtained, and the mixed impedance value R of the bipolar plate under test is... singel= 2*R1+R3, where R3 is the bulk resistance of the bipolar plate under test, providing basic data for the subsequent comparison calculation of mixed impedance values ​​of multiple plates. Subsequently, by applying pressure to several bipolar plates with the same preset pressure gradient as the single bipolar plate under test, the mixed impedance value of multiple bipolar plates under test is obtained, constructing the basic data for multi-plate testing, and providing multi-plate data support for subsequent difference calculation. Finally, the difference between the mixed impedance values ​​of multiple bipolar plates and the mixed impedance values ​​of a single bipolar plate is calculated, which is the contact resistance of n-1 bipolar plates under test and the bulk resistance of n-1 bipolar plates under test, (n-1)R2+(n-1)R0. The difference data is used as the optimized mixed impedance value of the bipolar plate under test, which amplifies the signals of bulk resistance and contact resistance. Since the bulk resistance R0 of the bipolar plate under test is increased by (n-1) times, and the contact resistance R2 is also increased by (n-1) times, the overall test accuracy will be greatly improved and the random error in the single-plate test will be diluted, thus improving the accuracy of subsequent mixed resistance function fitting and resistance separation.

[0102] Furthermore, the pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including:

[0103] Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient.

[0104] Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

[0105] In this embodiment, the bipolar plate under test is gradually pressurized by combining a preset pressure gradient and a preset pressure time. The preset pressure time can be 30s-120s. In this embodiment, the average value measured by the resistance meter within 30-60s after reaching the specified pressure can be taken as the mixed impedance value of the bipolar plate under test. This ensures that the pressure and resistance values ​​are sufficiently stable at each pressure point, avoiding impedance data fluctuations caused by unstable pressure. This allows for the acquisition of stable and reliable mixed impedance values ​​corresponding to each pressure gradient point, providing high-quality data support for subsequent data processing.

[0106] The present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the functions of the system as described above.

[0107] Please see Figure 4 A 25cm 2The graph shows a comparison between the fitted and measured values ​​of the hybrid resistance of the molded graphite plate in this embodiment. The fitting model used in this embodiment is an exponential model, and its specific mathematical expression after exponential fitting is y = y0 + Aexp(R0*x), where y represents the contact resistance of the bipolar plate to be measured, x represents the pressure, and y0, A, and R0 are the fitting parameters to be determined. The possible values ​​for y0 are 0.65776 ± 0.01144, A is 0.87629 ± 0.01555, and R0 is -0.96519 ± 0.0488. The reduced chi-square value (Reduced Chi-Sq) is a statistic used to measure the goodness of fit, and its possible value is 1.18085E-4. The smaller this value, the smaller the deviation between the fitted result and the original data, and the better the fitting effect. R-squared (COD) is the coefficient of determination, with a value of 0.99785. The closer it is to 1, the higher the proportion of variation in the original data explained by the fitted exponential function, and the better the fit. After adjustment, R-squared is 0.99731. Finally, we obtain the red line after fitting the data column B (corresponding to the contact resistance data of the molded plate monopole) in sheet1, and the measured dotted line. It can be seen that the fitting effect of both lines is very good.

[0108] Please see Figure 5 A 25cm 2 The image shows a comparison between the fitted and measured values ​​of the hybrid resistance of the engraved graphite plate in this embodiment. The fitting model used in this embodiment is an exponential model, and its specific mathematical expression after exponential fitting is y = y0 + Aexp(R0*x), where y represents the contact resistance of the bipolar plate to be measured, x represents the pressure, and y0, A, and R0 are the fitting parameters to be determined. The possible values ​​for y0 are 0.0954 ± 0.00437, A is 0.13406 ± 0.00518, and R0 is -0.91534 ± 0.10934. The reduced chi-square value (Reduced Chi-Sq) is a statistic used to measure the goodness of fit, and its possible value is 1.4602E-5. The smaller this value, the smaller the deviation between the fitted result and the original data, and the better the fitting effect. R-squared (COD) is the coefficient of determination, with a value of 0.98893. The closer it is to 1, the higher the proportion of variation in the original data explained by the fitted exponential function, and the better the fit. After adjustment, R-squared is 0.98616. Finally, we obtain the red line after fitting the data column B (corresponding to the contact resistance data of the engraved plate's single electrode) in sheet1, and the measured square dotted line. It can be seen that the fitting effect of both lines is very good.

[0109] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for testing the resistance of bipolar plates in a fuel cell, characterized in that, include: Obtain the bipolar plate to be tested; A pressure test is performed on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test. A hybrid resistance function is established based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test. The mixed resistance function is nonlinearly fitted to solve for the resistance value of the bipolar plate to be measured; Based on the mixed impedance value of the bipolar plate under test and the bulk resistance value of the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

2. The method for testing the bipolar plate resistance of a fuel cell according to claim 1, characterized in that, The acquisition of the bipolar plate under test includes: Obtain the original bipolar plate under test; The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

3. The method for testing the bipolar plate resistance of a fuel cell according to claim 1, characterized in that, The step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes: There are several bipolar plates to be tested; A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test. Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test. The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

4. The method for testing the bipolar plate resistance of a fuel cell according to claim 1, characterized in that, The step of performing a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test includes: Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient. Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

5. The method for testing the bipolar plate resistance of a fuel cell according to claim 1, characterized in that, The contact resistance value of the bipolar plate under test is obtained based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell. Specifically: Based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, the initial contact resistance value of the bipolar plate under test is obtained. Obtain the contact area of ​​the bipolar plate under test; Based on the initial contact resistance value and contact area of ​​the bipolar plate under test, the contact resistance value of the bipolar plate under test is obtained, thereby realizing the test of the bipolar plate resistance of the fuel cell.

6. A testing system for the bipolar plate resistance of a fuel cell, characterized in that, It includes a bipolar plate acquisition module, a pressure testing module, a function establishment module, a volume resistance calculation module, and a contact resistance calculation module, specifically: The bipolar plate acquisition module is used to acquire the bipolar plate to be tested; The pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test. The function establishment module is used to establish a hybrid resistance function based on a preset pressure gradient and the hybrid impedance value of the bipolar plate under test; The bulk resistance calculation module is used to perform nonlinear fitting on the hybrid resistance function to solve for the bulk resistance value of the bipolar plate to be measured. The contact resistance calculation module is used to obtain the contact resistance value of the bipolar plate under test based on the mixed impedance value and the bulk resistance value of the bipolar plate under test, thereby realizing the test of the bipolar plate resistance of the fuel cell.

7. The fuel cell bipolar plate resistance testing system according to claim 6, characterized in that, The bipolar plate acquisition module is used to acquire the bipolar plate to be tested; it includes: Obtain the original bipolar plate under test; The original bipolar plate to be tested is preprocessed to obtain the bipolar plate to be tested.

8. The fuel cell bipolar plate resistance testing system according to claim 6, characterized in that, The pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including: There are several bipolar plates to be tested; A pressure test is performed on any bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of a single bipolar plate under test. Pressure tests are performed on several bipolar plates under test based on a preset pressure gradient to obtain the mixed impedance value of multiple bipolar plates under test. The mixed impedance value of the bipolar plate under test is obtained based on the mixed impedance value of a single bipolar plate under test and the mixed impedance value of multiple bipolar plates under test.

9. The fuel cell bipolar plate resistance testing system according to claim 6, characterized in that, The pressure testing module is used to perform a pressure test on the bipolar plate under test based on a preset pressure gradient to obtain the mixed impedance value of the bipolar plate under test; including: Based on a preset pressure gradient and a preset pressure time, a pressure test is performed on the bipolar plate under test to obtain several mixed impedance values ​​of the bipolar plate under test corresponding to the preset pressure gradient. Based on the mixed impedance values ​​of several bipolar plates under a preset pressure gradient, the mixed impedance value of the bipolar plate under test is obtained.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it performs the functions of the system as described in any one of claims 6 to 9.

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