Method for determining the degree of activation and termination conditions of activation of a fuel cell

Abstract

The application provides a fuel cell activation degree and activation termination condition judgment method, and belongs to the field of fuel cells. A first polarization curve of a completed activation fuel cell is obtained, and a corresponding voltage under a rated current is obtained. The fuel cell is activated again, and a first excitation response curve is collected and recorded when the activated fuel cell works stably and reaches an excitation threshold. After the fuel cell continuously operates for 1-2 hours under the rated current, the above steps are repeated again to obtain a corresponding voltage under the rated current in a second polarization curve and a second excitation response curve. A first judgment standard parameter is calculated according to the first and second polarization curves, and a second judgment standard parameter is calculated according to the first and second excitation response curves. When the first judgment standard parameter is greater than or equal to a first set value, and the second judgment standard parameter is greater than or equal to a second set value, the activation termination standard is reached. The two judgment standards evaluate the activation degree of the fuel cell, and the activation state of the fuel cell is fully evaluated.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a method for determining the activation level and activation termination conditions of a fuel cell. Background Technology

[0002] Fuel cells, with their advantages of fast start-up, high efficiency, and zero pollution, can be applied to stationary power sources, transportation, and portable power sources, showing broad development prospects. Newly produced fuel cell stacks typically have poor initial performance due to impurities and poor hydration. Therefore, they undergo an activation process before leaving the factory to improve their internal condition and enhance battery performance to meet the power requirements of practical applications.

[0003] While there are various activation methods available, a universal standard for evaluating the activation level of fuel cells and criteria for determining activation termination are still lacking. Inappropriate activation methods and durations can lead to insufficient or excessive activation, affecting subsequent operation and wasting resources. Currently, the activation level of fuel cells is typically determined by testing the polarization curve, followed by constant current loading for a certain period, and then testing the polarization curve again. When the two curves essentially overlap, the fuel cell is considered activated. However, the constant current loading test is time-consuming. For example, Chinese invention patent CN116364997A, "An Activation Method for a Fuel Cell Stack," determines activation completion by detecting whether the stack performance meets the standards. This is mainly achieved by detecting the stack's voltage and output power. When the detected voltage is greater than or equal to a preset voltage, or the detected output power is greater than or equal to a preset power, it indicates that the stack performance meets the standards and activation is complete. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to address the lack of evaluation methods for the activation degree of fuel cells in the prior art, and avoid insufficient or excessive activation of fuel cells.

[0005] This invention solves the above-mentioned technical problems through the following technical solution: a method for determining the activation degree and activation termination conditions of a fuel cell, comprising the following steps:

[0006] Step 10: Obtain the first polarization curve of the activated fuel cell and get the voltage U1 corresponding to the rated current;

[0007] Step 20: Activate the fuel cell again. Once the activated fuel cell has stabilized and reached the excitation threshold, collect and record the first excitation response curve. The excitation threshold is the maximum value that the single cell voltage can reach, which is set before the excitation begins.

[0008] Step 30: After the fuel cell has been running at rated current for 1-2 hours, repeat steps 10 and 20 to obtain the voltage U2 and the second excitation response curve corresponding to rated current in the second polarization curve.

[0009] Step 40: Calculate the first judgment standard parameter based on the first polarization curve and the second polarization curve, and calculate the second judgment standard parameter based on the first excitation response curve and the second excitation response curve.

[0010] Step 50: When the first judgment standard parameter is greater than or equal to the first set value and the second judgment standard parameter is greater than or equal to the second set value, the fuel cell reaches the activation termination standard.

[0011] This invention applies multiple excitations to a fully activated fuel cell. If the fuel cell is not fully activated, its performance will change after the excitation is applied. If the fuel cell is fully activated, the first and second judgment criteria parameters used in this invention will meet the requirements. By evaluating the degree of activation of the fuel cell using two judgment criteria, a full evaluation of the activation state of the fuel cell can be achieved to determine a reasonable degree of activation.

[0012] Preferably, the fuel cell activated in step 10 is activated by any one or a combination of several of the following methods: forced load activation, hydrogen pump activation, gas shortage activation, and short circuit activation.

[0013] Preferably, the method of reactivating the fuel cell in step 20 is any one or any combination of several of the following: forced load activation, hydrogen pump activation, gas shortage activation, and short circuit activation.

[0014] Preferably, the fuel cell is reactivated in step 20 by either forward hydrogen pump activation or reverse hydrogen pump activation.

[0015] Preferably, when performing forward hydrogen pump activation on the fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated. A current excitation from the anode to the cathode is applied to the fuel cell to be activated. When performing reverse hydrogen pump activation on the fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated. A current excitation from the cathode to the anode is applied to the fuel cell to be activated.

[0016] Preferably, the first judgment criterion parameter is calculated as follows:

[0017] Wherein, η1 is the first judgment standard parameter, U1 is the voltage corresponding to the rated current obtained from the first polarization curve test, and U2 is the voltage corresponding to the rated current obtained from the second polarization curve test.

[0018] Preferably, the calculation steps for the second judgment criterion parameter are as follows:

[0019] Step 41: During the first excitation, calculate the time taken for each cell of the fuel cell to reach voltage levels of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8 volts, respectively, from the application of the excitation current. i is a positive integer ranging from 1 to 8, and j represents the serial number of the fuel cell unit. The time taken for each fuel cell unit during the second excitation process, from the application of the excitation current until the voltage rises to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, respectively, is recorded. i is a positive integer from 1 to 8, and j represents the serial number of the fuel cell unit. This step generates a total of 8×j time data points.

[0020] Step 42: Calculate the corresponding time difference. A total of 8×j time difference data points were generated;

[0021] Step 43, Statistics Given the number of data points m, calculate the second judgment criterion parameter η2. Where η2 is the second judgment criterion parameter, m represents the number of time differences less than or equal to 1s, and j represents the serial number of the fuel cell unit.

[0022] Preferably, in step 50, the first setting value is 99% and the second setting value is 90%.

[0023] The beneficial effects of this invention are:

[0024] This invention applies multiple excitations to a fully activated fuel cell. If the fuel cell is not fully activated, its performance will change after the excitation is applied. If the fuel cell is fully activated, the first and second judgment criteria parameters used in this invention will meet the conditions. By evaluating the degree of activation of the fuel cell using these two judgment criteria, a full evaluation of the activation state of the fuel cell can be achieved to determine a reasonable degree of activation. Attached Figure Description

[0025] Figure 1 A flowchart illustrating a method for determining the activation level and activation termination conditions of a fuel cell, provided as an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] like Figure 1 As shown, this embodiment provides a method for determining the activation level and activation termination conditions of a fuel cell, including the following steps:

[0028] Step 10: Obtain the first polarization curve of the activated fuel cell and get the voltage U1 corresponding to the rated current.

[0029] The activation methods for fuel cells include forced load activation, hydrogen pump activation, gas shortage activation, and short-circuit activation. When activating a fuel cell, any one or any combination of the above activation methods can be used. The method for judging the degree of activation and activation termination conditions of the fuel cell in this invention is applicable to any of the above activation methods.

[0030] Step 20: Activate the fuel cell again. Once the activated fuel cell has stabilized and reached the excitation threshold, collect and record the first excitation response curve.

[0031] The fuel cell can be reactivated by any one or a combination of several of the following methods: forced load activation, hydrogen pump activation, gas shortage activation, and short circuit activation.

[0032] This invention is illustrated using forward hydrogen pump activation or reverse hydrogen pump activation as examples. When performing forward hydrogen pump activation on a fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated. A current excitation from the anode to the cathode is applied to the fuel cell to be activated. When performing reverse hydrogen pump activation on a fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated. A current excitation from the cathode to the anode is applied to the fuel cell to be activated.

[0033] The inert gas can be one or more of nitrogen, helium, and argon, or other inert gases that do not readily undergo redox reactions with hydrogen.

[0034] It should be noted that the excitation threshold is a voltage value, that is, the maximum value that the single-chip voltage can reach before the excitation starts, which generally does not exceed 1V.

[0035] Step 30: After the fuel cell has been running at rated current for 1-2 hours, repeat steps 10 and 20 to obtain the voltage U2 and the second excitation response curve corresponding to rated current in the second polarization curve.

[0036] Step 40: Calculate the first judgment standard parameter based on the first polarization curve and the second polarization curve, and calculate the second judgment standard parameter based on the first excitation response curve and the second excitation response curve.

[0037] The first judgment criterion parameter is calculated as follows:

[0038] Wherein, η1 is the first judgment standard parameter, U1 is the voltage corresponding to the rated current obtained from the first polarization curve test, and U2 is the voltage corresponding to the rated current obtained from the second polarization curve test.

[0039] The calculation steps for the second judgment criterion parameter are as follows:

[0040] Step 41: During the first excitation, calculate the time taken for each cell of the fuel cell to reach voltage levels of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8 volts, respectively, from the application of the excitation current. i is a positive integer ranging from 1 to 8, and j represents the serial number of the fuel cell unit. The time taken for each fuel cell unit during the second excitation process, from the application of the excitation current until the voltage rises to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, respectively, is recorded. i is a positive integer ranging from 1 to 8, and j represents the serial number of the fuel cell unit. This step generates a total of 8×j time data points.

[0041] Step 42: Calculate the corresponding time difference. A total of 8×j time difference data points were generated.

[0042] Step 43, Statistics Given the number of data points m, calculate the second judgment criterion parameter η2. Where η2 is the second judgment criterion parameter, m represents the number of time differences less than or equal to 1s, and j represents the serial number of the fuel cell unit.

[0043] Step 50: When both η1≥99% and η2≥90% are satisfied, the fuel cell reaches the activation termination criterion. If only one of the conditions, η1≥99% and η2≥90%, is satisfied, it is determined that the activation termination criterion has not been reached.

[0044] Currently, the determination of the activation degree of fuel cells usually involves testing the polarization curve, then applying a constant current load for a certain period of time, and testing the polarization curve again. When the two curves basically overlap, the fuel cell can be considered to be fully activated. However, the constant current load test takes a long time. This invention applies multiple excitations to the activated cell, which is equivalent to rapid activation. If the fuel cell is not fully activated, its performance will change after applying the excitation. If the fuel cell is fully activated, the first and second judgment criteria parameters used in this invention will meet the set conditions. By evaluating the activation degree of the fuel cell using two judgment criteria, a full evaluation of the activation state of the fuel cell can be achieved to determine a reasonable activation degree.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the activation degree and activation termination conditions of a fuel cell, characterized in that: Includes the following steps: Step 10: Obtain the first polarization curve of the activated fuel cell and get the voltage corresponding to the rated current. U 1; Step 20: Activate the fuel cell again. Once the activated fuel cell has stabilized and reached the excitation threshold, collect and record the first excitation response curve. The excitation threshold is the maximum value that the single cell voltage can reach, which is set before the excitation begins. Step 30: After the fuel cell has been running continuously at rated current for 1-2 hours, repeat steps 10 and 20 to obtain the voltage corresponding to rated current in the second polarization curve. U 2. The second excitation response curve; Step 40: Calculate the first judgment standard parameter based on the first polarization curve and the second polarization curve; calculate the second judgment standard parameter based on the first excitation response curve and the second excitation response curve; the calculation method for the first judgment standard parameter is as follows: ,in, The primary criterion parameter is... U 1 represents the voltage corresponding to the rated current obtained from the first polarization curve test. U 2 represents the voltage corresponding to the rated current obtained from the second polarization curve test; Step 50: When the first judgment standard parameter is greater than or equal to the first set value and the second judgment standard parameter is greater than or equal to the second set value, the fuel cell reaches the activation termination standard. The first set value is 99% and the second set value is 90%.

2. The method for determining the activation degree and activation termination conditions of a fuel cell according to claim 1, characterized in that: The activated fuel cell in step 10 is activated by any one or a combination of several of the following methods: forced load activation, hydrogen pump activation, gas shortage activation, and short circuit activation.

3. The method for determining the activation degree and activation termination conditions of a fuel cell according to claim 1, characterized in that: In step 20, the fuel cell is reactivated in any one or a combination of several of the following methods: forced load activation, hydrogen pump activation, gas shortage activation, and short circuit activation.

4. The method for determining the activation degree and activation termination conditions of a fuel cell according to claim 3, characterized in that: In step 20, the fuel cell is reactivated by either forward hydrogen pump activation or reverse hydrogen pump activation.

5. The method for determining the activation degree and activation termination conditions of a fuel cell according to claim 4, characterized in that: When performing forward hydrogen pump activation on a fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated. A current excitation is applied to the fuel cell from the anode to the cathode. When performing reverse hydrogen pump activation on a fuel cell, a mixture of inert gas and hydrogen or pure hydrogen is introduced into the cathode of the fuel cell to be activated, and an inert gas or a mixture of inert gas and hydrogen or pure hydrogen is introduced into the anode of the fuel cell to be activated. A current excitation is applied to the fuel cell from the cathode to the anode.

6. The method for determining the activation degree and activation termination conditions of a fuel cell according to claim 1, characterized in that: The calculation steps for the second judgment criterion parameter are as follows: Step 41: During the first excitation, calculate the time taken for each cell of the fuel cell to reach voltage levels of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8 volts, respectively, from the application of the excitation current. , i For positive integers ranging from 1 to 8, j This indicates the serial number of each fuel cell unit. During the second excitation, the time taken for each fuel cell unit from the application of the excitation current until the voltage rises to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, respectively, is recorded. , i For positive integers ranging from 1 to 8, j This indicates the serial number of the fuel cell unit; this step generates a total of 8× j Data for each time period; Step 42: Calculate the corresponding time difference. A total of 8× j Time difference data; Step 43, Statistics Calculate the second judgment criterion parameter m, which is the number of data points ≤1s. , ,in, The second criterion parameter is m, which represents the number of time differences less than or equal to 1 second. j This indicates the serial number of a single fuel cell unit.

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