Sensitivity evaluation method of fuel cell membrane electrode

Abstract

The invention discloses a sensitivity evaluation method of a fuel cell membrane electrode, which adopts a data analysis method to realize the analysis of sensitivity parameters so as to quickly determine the optimal operation condition of the membrane electrode. The method comprises the following steps: sampling a membrane electrode sample, then activating the corresponding membrane electrode sample, and after the membrane electrode is activated, performing a polarization test, an anode excess coefficient sensitivity test, a cathode excess coefficient sensitivity test, a battery temperature sensitivity test, an anode air inlet humidity sensitivity test and a cathode air inlet humidity sensitivity test through sensitivity parameter setting. And analyzing the data obtained by various tests to obtain the corresponding sensitivity parameter value of the corresponding membrane electrode under the optimal operation condition.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a sensitivity evaluation method for a fuel cell membrane electrode. Background Art

[0002] As the core component of fuel cells, membrane electrode has an extremely important impact on the output performance and environmental adaptability of fuel cells. Usually, membrane electrode testing has a certain guiding significance for the output performance of fuel cell stacks. For the performance test of membrane electrode, conventional methods require multiple tests, which is time-consuming and labor-intensive. Therefore, how to quickly obtain the optimal working conditions for the stable operation of the battery is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above problems, the present invention provides a method for evaluating the sensitivity of a fuel cell membrane electrode, which uses a data analysis method to analyze sensitivity parameters, thereby quickly determining the optimal operating conditions of the membrane electrode.

[0004] A method for evaluating the sensitivity of a fuel cell membrane electrode, characterized in that:

[0005] Take samples of membrane electrode and then activate the corresponding membrane electrode samples. After the membrane electrode activation is completed, perform polarization test, anode excess coefficient sensitivity test, cathode excess coefficient sensitivity test, battery temperature sensitivity test, anode air intake humidity sensitivity test and cathode air intake humidity sensitivity test through sensitivity parameter setting. Analyze the data obtained from each test to obtain the corresponding sensitivity parameter value under the optimal operating conditions of the corresponding membrane electrode.

[0006] It is further characterized by:

[0007] Before activation of the membrane electrode sample, a membrane electrode sample with an active area of ​​a set value is prepared, and activation is started after assembling a single cell. Before activating the membrane electrode, the test conditions are first waited for. The test conditions include the single cell temperature value, the intake gas flow rate, the intake humidity, and the cell back pressure. After the test conditions have reached the set values, the activation process is started;

[0008] After the test conditions reach the set value, the membrane electrode samples are activated, and the activation process is load increase-stabilization-load reduction;

[0009] During the load increase process, according to the current density range value, the current density range is increased from 0 to the set maximum current density value within the load increase setting time in a step-by-step manner;

[0010] During the stabilization process, within the set stabilization time range, the current density range is always maintained at the highest current density value;

[0011] During the load reduction process, the maximum current density value is reduced to 0 within the load reduction setting time in a step-by-step manner;

[0012] The test conditions during the activation process are as follows: the temperature of the single cell is controlled at 80±1℃, the intake gas flow is controlled according to the excess coefficient: 1.5 for the anode and 1.8 for the cathode; the intake humidity is 60% RH, and the battery back pressure is 1.2 bar for the anode and 1.0 bar for the cathode;

[0013] Before the polarization test of the membrane electrode, wait for the test conditions, including the single cell temperature value, intake gas flow, intake humidity, and battery back pressure. After each condition reaches the set value, start the polarization test. Each test point runs stably for the set time, and the average value of the latter period is taken. When the battery voltage is less than 0.3V during the loading process, the loading is stopped. Among them, the single cell temperature value, intake gas flow, intake humidity, and battery back pressure parameters only change one parameter value each time they are measured, so as to obtain the optimal value of the sensitive parameter under the same other parameters. The subsequent test is carried out according to the optimal value of the sensitive parameter obtained last time to carry out the next polarization test until the corresponding sensitivity parameter value under the optimal operating conditions of the membrane electrode is obtained;

[0014] Each polarization test includes load increase and load decrease;

[0015] The holding time of load increase and load reduction in each polarization test is the same, and the step value is the same. The load increase process of the polarization test is to increase the current density range from 0 to the set test maximum current density value in a step-by-step manner within the load increase setting time. The load reduction process of the polarization test is to reduce the test maximum current density value to 0 in a step-by-step manner within the load reduction setting time. The average value of the output voltage in the latter part of the load reduction process is taken for each polarization test.

[0016] After adopting the above technical scheme, polarization test, anode excess coefficient sensitivity test, cathode excess coefficient sensitivity test, battery temperature sensitivity test, anode air intake humidity sensitivity test and cathode air intake humidity sensitivity test are carried out through sensitivity parameter setting, and the data obtained from each test are analyzed to obtain the corresponding sensitivity parameter values ​​under the optimal operating conditions of the corresponding membrane electrode, so as to quickly determine the optimal operating conditions of the membrane electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the activation process of the membrane electrode according to a specific embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the process of each polarization test of the membrane electrode according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0019] A method for evaluating the sensitivity of a fuel cell membrane electrode, a specific embodiment, prepares a membrane electrode sample with an active area of ​​5*5cm2, assembles a single cell and starts activation. Before activating the membrane electrode, wait for the test conditions. The test conditions include controlling the temperature of the single cell at 80±1°C, and the intake gas flow rate is controlled according to the excess coefficient: 1.5 for the anode and 2.0 for the cathode; the intake humidity is 100% RH, and the battery back pressure is 1.2 bar for the anode and 1.0 bar for the cathode. The back pressure mentioned refers to the gauge pressure. After each condition reaches the set value, the activation process begins. The specific steps are shown in Figure 1 As shown:

[0020] The loading process is extremely constant current activation 1, and the current density range is: 0~2A / cm 2 ; Step value: 0.1A / cm 2 / point; holding time: 60s / point;

[0021] The stabilization process is constant current activation 2, and the current density range is: 2A / cm 2 Cross-flow operation, holding time: 15min;

[0022] The load reduction process is constant current activation 3, and the current density range is: 2~0A / cm 2 ; Step value: 0.2A / cm 2 / point; holding time: 60s / point.

[0023] The above-mentioned activated single cell is subjected to polarization test. Before the polarization test of the membrane electrode, the test conditions are first waited for. The test conditions include that the temperature of the single cell is controlled at 80±1°C, the intake gas flow rate is controlled according to the excess coefficient: 1.5 (Anode), 1.8 (Cathode); the intake humidity is 60% RH, and the battery back pressure is 1.2 bar (Anode), 1.0 bar (Cathode). After each condition reaches the set value, the polarization test is started. Each test point runs stably for 360s, and the average value of the last 60s is taken. When the battery voltage is less than 0.3V during the loading process, the loading is no longer continued. Among them, the parameters of the single cell temperature value, the intake gas flow rate, the intake humidity, and the battery back pressure only change one of the parameter values ​​in each measurement, so as to obtain the optimal value of the sensitive parameter under the same other parameters. The subsequent test is carried out according to the optimal value of the sensitive parameter obtained in the previous test to carry out the next polarization test until the corresponding sensitivity parameter value under the optimal operating conditions of the membrane electrode is obtained;

[0024] Each polarization test includes load increase and load decrease. The specific steps are as follows: Figure 2 As shown:

[0025] When the load is increased, the current density range is: 0~3A / cm 2; Step value: 0.1A / cm 2 / point; holding time: 180s / point;

[0026] When the load is reduced, the current density range is: 3~0A / cm 2 ; Step value: 0.1A / cm 2 / point; holding time: 180s / point.

[0027] S1. Anode excess coefficient sensitivity test. When the output current is 25A-50A, the cathode flow rate remains unchanged. The output voltage when the anode excess coefficient (corresponding to the anode intake flow rate) decreases is tested. After reaching each operating condition, wait for 300 seconds and take the average value of the last 60 seconds of data. When the battery voltage is less than 0.3V during the loading process, loading will no longer continue. Table 1 shows the anode excess coefficient parameter settings.

[0028]

[0029] Table 1

[0030] When the output current is 25A, the anode excess coefficient drops from 1.8 to 1.1, and the output voltage drops from 0.682V to 0.680V; when the output current is 37.5A, the anode excess coefficient drops from 1.8 to 1.1, and the output voltage drops from 0.568V to 0.562V; when the output current is 50A, the anode excess coefficient drops from 1.8 to 1.1, and the output voltage drops from 0.383V to 0.378V. With the change of the anode excess coefficient, the single battery can output stably, and the anode excess coefficient has little effect on the stable performance of the battery.

[0031] S2, cathode excess coefficient sensitivity test, when the output current is 25A ~ 50A, the anode flow rate remains unchanged, and the output voltage when the cathode excess coefficient (corresponding cathode intake flow rate) decreases is tested. After reaching each operating condition, wait for 300 seconds and take the average value of the last 60 seconds of data. When the battery voltage is less than 0.3V during the loading process, the loading will no longer continue. Table 2 shows the cathode excess coefficient parameter settings.

[0032]

[0033]

[0034] Table 2

[0035] When the output current is 25A, the cathode excess coefficient drops from 3.0 to 1.2, and the output voltage drops from 0.726V to 0.653V; when the output current is 37.5A, the cathode excess coefficient drops from 3.0 to 1.2, and the output voltage drops from 0.615V to 0.472V; when the output current is 50A, the cathode excess coefficient drops from 3.0 to 1.2, and the output voltage drops from 0.458V to 0.132V; and the output voltage increases from 2.5 to 3.0, and the increase in output voltage is small. With the change of the cathode excess coefficient, the output performance of the single cell changes greatly, and the reasonable increase of the cathode excess coefficient can greatly improve the performance of the single cell.

[0036] S3, battery temperature sensitivity test, when the output current is 25A ~ 50A, test the polarization performance at different battery temperatures, wait for 300s after reaching each working condition and take the average value of the last 60s data. When the battery voltage is less than 0.3V during the loading process, the loading will not continue. Table 3 shows the battery temperature parameter settings.

[0037]

[0038]

[0039] Table 3

[0040] When the output current is 25A~50A, the battery temperature increases from 50℃ to 85℃, the output voltage first increases and then decreases, and the voltage increase decreases accordingly. The maximum output voltage value when the battery temperature is 80℃ is 0.682V@1A / cm2; the change in battery temperature has a certain impact on the battery stability performance, because the proton membrane of the battery is dehydrated due to high temperature, and the reduction in the wetness of the membrane will lead to an increase in the internal resistance of the battery, which correspondingly reduces the output performance of the battery. Therefore, appropriately increasing the operating temperature can improve the steady-state output performance of the battery.

[0041] S4, anode air intake humidity sensitivity test, when the output current is 25A ~ 50A, test the polarization performance under different anode air intake humidity, wait for 300s after reaching each working condition and take the average value of the last 60s data. When the battery voltage is less than 0.3V during the loading process, the loading will not continue. Table 4 shows the anode air intake humidity parameter settings.

[0042]

[0043]

[0044] Table 4

[0045] When the output current is 25-50A, the anode intake air humidity drops from 100% to 40%, and the output voltage drops accordingly. As the current increases, the output voltage drops more. When the intake air humidity drops from 100% to 60%, the output voltage drops less. When the anode intake air humidity changes within a certain range, the battery can output stably.

[0046] S5. Cathode air intake humidity sensitivity test. When the output current is 25A to 50A, the polarization performance under different cathode air intake humidity is tested. After reaching each working condition, wait for 300 seconds and take the average value of the last 60 seconds of data. When the battery voltage is less than 0.3V during the loading process, the loading will not continue. Table 5 shows the cathode air intake humidity parameter settings.

[0047]

[0048]

[0049] Table 5

[0050] When the output current is 25-50A, the cathode intake air humidity drops from 100% to 40%, and the output voltage drops accordingly. When the intake air humidity drops from 100% to 60%, the output voltage drops less. When the cathode intake air humidity changes within a certain range, the battery can output stably.

[0051] By setting the sensitivity parameters, the optimal working conditions for the stable operation of the fuel cell membrane electrode are determined. For example, for the membrane electrode in the case, by setting the sensitivity parameters, an anode excess coefficient of 1.5, a cathode excess coefficient of 2.5, a battery temperature of 80°C, and a cathode and cathode air intake humidity of 60% RH / 60% RH are selected as the optimal working conditions for the stable operation of the battery.

[0052] Polarization test, anode excess coefficient sensitivity test, cathode excess coefficient sensitivity test, battery temperature sensitivity test, anode air intake humidity sensitivity test and cathode air intake humidity sensitivity test are carried out through sensitivity parameter setting. The data obtained from each test are analyzed to obtain the corresponding sensitivity parameter values ​​under the optimal operating conditions of the corresponding membrane electrode, so as to quickly determine the optimal operating conditions of the membrane electrode.

[0053] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0054] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for evaluating the sensitivity of a fuel cell membrane electrode, characterized in that: Take samples of membrane electrode and then activate the corresponding membrane electrode samples. After the membrane electrode activation is completed, perform polarization test, anode excess coefficient sensitivity test, cathode excess coefficient sensitivity test, battery temperature sensitivity test, anode air intake humidity sensitivity test and cathode air intake humidity sensitivity test through sensitivity parameter setting. Analyze the data obtained from each test to obtain the corresponding sensitivity parameter value under the optimal operating conditions of the corresponding membrane electrode.

2. The method for evaluating the sensitivity of a fuel cell membrane electrode according to claim 1, characterized in that: Before activation of the membrane electrode sample, a membrane electrode sample with an active area of ​​a set value is prepared, and activation begins after assembling a single cell. Before activating the membrane electrode, wait for the test conditions, which include the single cell temperature value, intake gas flow rate, intake humidity, and cell back pressure. After all the test conditions reach the set values, the activation process begins.

3. A fuel cell membrane electrode sensitivity evaluation method according to claim 2, characterized in that: After the test conditions reach the set values, the membrane electrode samples are activated, and the activation process is load increase-stabilization-load reduction.

4. A fuel cell membrane electrode sensitivity evaluation method according to claim 3, characterized in that: During the load increase process, according to the current density range value, the current density range is increased from 0 to the set maximum current density value within the load increase setting time in a step-by-step manner.

5. The method for evaluating the sensitivity of a fuel cell membrane electrode according to claim 3, characterized in that: During the stabilization process, within the set stabilization time range, the current density range is always maintained at the highest current density value.

6. The method for evaluating the sensitivity of a fuel cell membrane electrode according to claim 1, characterized in that: During the load reduction process, the maximum current density value is reduced to 0 within the load reduction setting time in a step-by-step manner.

7. The method for evaluating the sensitivity of a fuel cell membrane electrode according to claim 2, characterized in that: The test conditions during the activation process are as follows: the temperature of the single cell is controlled at 80±1°C, the intake gas flow is controlled according to the excess coefficient: 1.5 for the anode and 1.8 for the cathode; the intake humidity is 60% RH, and the battery back pressure is 1.2 bar for the anode and 1.0 bar for the cathode.

8. The method for evaluating the sensitivity of a fuel cell membrane electrode according to claim 1, characterized in that: Before the polarization test of the membrane electrode, wait for the test conditions, including the single cell temperature value, intake gas flow, intake humidity, and battery back pressure. After each condition reaches the set value, start the polarization test. Each test point runs stably for a set time, and the average value of the latter period is taken. When the battery voltage is less than 0.3V during the loading process, the loading will not continue. Among them, the single cell temperature value, intake gas flow, intake humidity, and battery back pressure parameters only change one of the parameter values ​​in each measurement, so as to obtain the optimal value of the sensitive parameter under the same other parameters. The subsequent test will be carried out according to the optimal value of the sensitive parameter obtained in the previous test to carry out the next polarization test until the corresponding sensitivity parameter value under the optimal operating conditions of the membrane electrode is obtained.

9. A fuel cell membrane electrode sensitivity evaluation method according to claim 8, characterized in that: Each polarization test includes load increase and load decrease.

10. A fuel cell membrane electrode sensitivity evaluation method according to claim 9, characterized in that: The holding time of load increase and load reduction in each polarization test is the same, and the step value is the same. The load increase process of the polarization test is to increase the current density range from 0 to the set test maximum current density value in a step-by-step manner within the load increase setting time. The load reduction process of the polarization test is to reduce the test maximum current density value to 0 in a step-by-step manner within the load reduction setting time. The average value of the output voltage in the latter part of the load reduction process is taken for each polarization test.

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