Rapid activation method for fuel cell

Abstract

The invention discloses a rapid activation method for a fuel cell. The rapid activation method comprises the following steps: S1, arranging the fuel cell on an electric pile test bench and completing connection; s2, initializing a fuel cell stack; s3, introducing preset gas into the cathode and the anode, and controlling opening and closing of an inlet electromagnetic valve and an outlet electromagnetic valve on the cathode side by taking a preset pressure difference delta U1 in the electric pile and a temperature difference threshold delta U2 as judgment conditions; controlling opening and closing of an inlet electromagnetic valve and an outlet electromagnetic valve on the anode side by taking the pressure difference delta U3 and the temperature difference threshold value delta U4 in the electric pile as judgment conditions; s4, respectively introducing battery working standard gas into the anode and the cathode, and recording the voltage of the galvanic pile; and S5, repeating the steps S3 and S4, and judging whether activation is completed or not according to the pile voltage recorded in the step S4. The cell in the scheme is short in activation time, less in required fuel and low in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell activation, in particular to a rapid activation method for fuel cell. BACKGROUND

[0002] The output voltage of a single cell of a fuel cell is low, about 0.5-1V, and in practical applications, a certain number of single cells are connected in series to form a fuel cell stack to meet the demand for high power of vehicle fuel cells. The last process of a fuel cell stack product is the activation of the stack, which is also a long-time-consuming and complex step in the whole process.

[0003] The activation of the stack generally requires a large current stage and a high potential stage to activate the performance state of the stack and to remove some impurities in the preliminary state of the membrane electrode in the stack. The high potential is not friendly to the catalyst of the fuel cell, especially the alloy catalyst, and the large current activation is a long-time process that consumes a lot of fuel. A high-power stack activation requires ≥5-10h, consumes several sets of fuel, and requires the use of a professional fuel cell test bench. The whole activation process of the stack is a great cost for the stack manufacturer, including professional equipment, time and fuel consumption, so a rapid activation method is urgently needed to reduce costs, improve efficiency and promote the development process of fuel cell industrialization. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a rapid activation method for the membrane electrode of a fuel cell membrane stack, which improves the activation time and fuel cost and has a certain recovery effect on the decay membrane electrode.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a rapid activation method for a fuel cell, comprising the following steps:

[0006] S1, arranging the fuel cell on a stack test bench and completing the connection;

[0007] S2, initializing the fuel cell stack;

[0008] S3, inputting preset gases to the cathode and the anode, and controlling the opening and closing of the inlet and outlet electromagnetic valves of the cathode side according to the preset pressure difference ΔU1 and temperature difference threshold value ΔU2 of the stack as the judgment condition; and controlling the opening and closing of the inlet and outlet electromagnetic valves of the anode side according to the pressure difference ΔU3 and temperature difference threshold value ΔU4 of the stack as the judgment condition;

[0009] S4, inputting standard cell working gases to the anode and the cathode respectively and recording the stack voltage;

[0010] S5, repeating steps S3 and S4 and judging whether the activation is completed according to the stack voltage recorded in step S4.

[0011] In step S2, the initialization of the fuel cell stack is completed by purging with inert gas to keep the stack dry and to fill the anode and cathode chambers with inert gas.

[0012] In step S2, the inert gas is nitrogen; the inlet and outlet electromagnetic valves of the cathode side and the anode side of the fuel cell stack are opened, and the stack is purged with nitrogen for a set time to keep the stack dry and to replace the anode and cathode chambers with nitrogen, after which the inlet and outlet valves of the cathode side and the anode side are closed.

[0013] In step S3, the inlet and outlet electromagnetic valves of the cathode side of the stack are opened, and hydrogen and air are introduced at a fixed pulse ratio, after which the inlet and outlet electromagnetic valves are closed; the initial pressure difference ΔU1 and the temperature difference threshold ΔU2 in the cathode side of the stack are recorded, and the air and hydrogen flow ratio is adjusted so that ΔU1 and ΔU2 are ≤5% of the original values.

[0014] In step S3, the inlet and outlet electromagnetic valves of the anode side of the stack are opened, and hydrogen and air are introduced at a fixed pulse ratio, after which the inlet and outlet electromagnetic valves are closed; the initial pressure difference ΔU3 and the temperature difference threshold ΔU4 in the anode side of the stack are recorded, and the air and hydrogen flow ratio is adjusted so that ΔU3 and ΔU4 are ≤5% of the original values.

[0015] In step S3, the introduction of hydrogen and air at a fixed pulse ratio includes first introducing air at a set flow rate for a duration T1, then switching to introducing hydrogen at a set flow rate for a duration T2, and repeating multiple times.

[0016] In step S4, the standard gas for the operation of the anode and the cathode is introduced, which includes replacing the anode and the cathode with hydrogen and air, respectively, and introducing air and hydrogen into the anode and the cathode at a metering ratio of 2.0 and a constant pressure of 50 kPa, and controlling the stack to operate at a constant current of 1A, and recording the voltage V 测 .

[0017] In step S5, the parameters ΔU1, ΔU2, ΔU3, and ΔU4 are repeated in steps S3 and S4, and the voltage V 测 .

[0018] According to the recorded voltage V after each cycle, when the difference between adjacent cycles is less than a set threshold, the activation is determined to be complete.

[0019] The advantages of the present application are: 1. The activation time of the stack is short, the requirements for the activation equipment are low, the fuel consumption is small, and the problem of high cost of activating batch-produced stacks is solved; 2. It has a restoring effect on the decay of long-term running stacks; BRIEF DESCRIPTION OF DRAWINGS

[0020] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0021] Figure 1 This is a flowchart of the activation method of the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0023] Example 1:

[0024] like Figure 1 As shown, this embodiment provides a rapid activation method for fuel cells, applied to the rapid activation of fuel cells at the factory delivery stage. The method utilizes a fuel cell stack test bench for testing, and the specific steps include the following:

[0025] S1. Arrange the fuel cell on the fuel cell stack test bench and complete the connection;

[0026] S2, Fuel cell stack initialization;

[0027] S3. Introduce a preset gas into the cathode and anode, and control the opening and closing of the cathode side inlet and outlet solenoid valves based on the preset pressure difference ΔU1 and temperature difference threshold ΔU2 within the fuel cell stack; control the opening and closing of the anode side inlet and outlet solenoid valves based on the pressure difference ΔU3 and temperature difference threshold ΔU4 within the fuel cell stack.

[0028] S4. The standard working gas of the battery is introduced into the anode and cathode respectively, and the stack voltage is recorded.

[0029] S5. Repeat steps S3 and S4 and determine whether activation is complete based on the stack voltage recorded in step S4.

[0030] This solution is applicable to the activation of fuel cells before they leave the factory. Therefore, in order to facilitate rapid activation control, a test bench for the fuel cell stack is used in step S1. This bench can control the fuel cell, including but not limited to the intake control of the anode and cathode, and the supply of corresponding gases, which facilitates subsequent activation control.

[0031] The fuel cell stack that needs to be activated is initialized in step S2. The main purpose of initialization is to discharge other gases inside the fuel cell, while keeping the inside dry, to avoid the influence of moisture or other gases in the internal cavity of the fuel cell stack on the activation effect; therefore, in step S2, the stack is kept in a dry state and the anode and cathode cavities in the stack are filled with inert gas by inert gas purging, thereby completing the initialization of the stack. The inert gas is mainly used to avoid chemical reaction in the stack. The inert gas has relatively stable chemical properties, and at the same time, the dry inert gas can also carry away the moisture, impurities and the like in the anode and cathode cavities. The inert gas selected in the present scheme is nitrogen; the inert gas in step S2 includes but is not limited to nitrogen; the inlet electromagnetic valve and the outlet electromagnetic valve of the cathode side and the anode side of the fuel cell stack are opened, nitrogen is used for purging for a set time, so that the stack is kept in a dry state and the anode and cathode cavities are replaced with nitrogen, then the inlet and outlet valves of the anode and cathode sides are closed. The set time of purging is obtained by pre-experiment calibration, which can make the nitrogen fill the anode and cathode cavities.

[0032] After purging is completed, the next step is to activate the fuel cell stack, i.e. steps S3 and S4 in the present scheme. The fuel cell is activated through steps S3 and S4, and whether the activation is completed is judged through step S5.

[0033] In step S3, the inlet electromagnetic valve and the outlet electromagnetic valve of the cathode side of the stack are opened, hydrogen and air are input at a fixed pulse ratio, and then the inlet electromagnetic valve and the outlet electromagnetic valve are closed; the initial pressure difference ΔU1 and the temperature difference threshold ΔU2 in the cathode side of the stack are recorded, and the flow ratio of air and hydrogen is adjusted so that ΔU1 and ΔU2≤5% of the original value. The fixed pulse ratio of hydrogen and air includes: first inputting air at a set flow rate for a time T1, then switching to inputting hydrogen at a set flow rate for a time T2, and repeating multiple times. The initial ΔU1 and ΔU2 refer to the difference between the pressure in the cathode cavity when the inlet electromagnetic valve and the outlet electromagnetic valve are closed and the pressure after 2 minutes, and the difference between the temperature in the cathode cavity when the inlet electromagnetic valve and the outlet electromagnetic valve are closed and the temperature after 2 minutes.

[0034] Simultaneously open the inlet and outlet electromagnetic valves on the anode side of the stack, and then close the inlet and outlet electromagnetic valves after a fixed pulse ratio of hydrogen and air is introduced. The initial pressure difference ΔU3 and temperature difference ΔU4 in the anode chamber are recorded, and the ratio of air and hydrogen flow is adjusted so that ΔU3 and ΔU4 are less than or equal to 5% of the original values. The fixed pulse ratio of hydrogen and air includes: first introducing air at a set flow rate for a duration T1, then switching to introducing hydrogen at a set flow rate for a duration T2, and repeating multiple times. The initial ΔU3 and ΔU4 refer to the difference between the pressure in the anode chamber when the inlet and outlet electromagnetic valves are closed and the pressure after 2 minutes, and the difference between the temperature in the anode chamber when the inlet and outlet electromagnetic valves are closed and the temperature after 2 minutes.

[0035] After the fuel cell core is adjusted in step S3, it is determined whether the activation is completed in step S4. In step S4, the anode and cathode are respectively introduced with standard cell operating gas, including replacing the anode and cathode with hydrogen and air, respectively, and introducing air and hydrogen into the anode and cathode at a metering ratio of 2.0 and a constant pressure of 50 kPa, and controlling the stack to operate at a constant current of 1 A. The voltage V 测 is recorded. The fuel cell is introduced with fuel under the condition that the fuel cell can operate normally, and the voltage V 测 of the fuel cell is tested.

[0036] Since a single cycle cannot effectively activate the fuel cell, steps S3 and S4 need to be repeated multiple times. In the repetition, the same state parameters ΔU1, ΔU2, ΔU3, and ΔU4 are matched, and steps S3 and S4 are repeated to obtain the voltage V 测 recorded in step S4 in each repetition.

[0037] After a certain number of cycles are repeated, the V 测 recorded in the last few cycles is compared to determine whether the activation is completed. When the difference between adjacent cycles V 测 is less than a set threshold, the activation is determined to be completed. The V 测 recorded in the last three cycles is selected, and the difference between any two V 测 is compared. When the difference between any two V 测 is less than a set threshold, the activation is determined to be completed, and the activation is ended. Otherwise, the activation is determined to be not completed, and steps S3-S5 are continued to be repeated. The set threshold is about 5 mv, and when the difference between any two V 测 is less than 5 mv, the activation is determined to be completed.

[0038] Example 2:

[0039] The purpose of the present application is to provide a fuel cell stack rapid activation method, which reduces the activation time, improves the activation effect, improves the utilization rate of the test platform, and avoids the waste of hydrogen.

[0040] As shown in Figure 1 The present application is a fuel cell membrane electrode assembly rapid activation method that improves the activation time and fuel cost while recovering the degraded membrane electrode

[0041] The technical scheme of the present application is:

[0042] S1: Open the inlet and outlet valves of the cathode side and anode side of the fuel cell stack, and use nitrogen to purge for a certain time to keep the stack dry and replace the nitrogen in the anode and cathode cavities, and close the inlet and outlet valves of the anode and cathode sides;

[0043] S2: Open the inlet electromagnetic valve of the cathode side of the stack, and pass in hydrogen and air at a fixed pulse ratio, and close the inlet electromagnetic valve;

[0044] S3: Take the pressure difference ΔU1 and temperature difference threshold ΔU2 in the stack as the judgment condition, open the inlet and outlet electromagnetic valves of the cathode side and replace the gas, and repeat the process for a certain period of time;

[0045] S4: Open the inlet electromagnetic valve of the anode side of the stack, and pass in hydrogen and air at a fixed pulse ratio, and close the inlet electromagnetic valve

[0046] S5: Take the pressure difference ΔU3 and temperature difference threshold ΔU4 in the stack as the judgment condition, open the inlet and outlet electromagnetic valves of the anode side and replace the gas, and repeat the process for a certain period of time;

[0047] S6: At the end of each cycle, replace the hydrogen in the anode and the air in the cathode with a constant current, and judge whether the voltage of the stack rises, and take the voltage difference of the last three cycles being less than 5mv as the judgment of the completion of the activation.

[0048] Taking the actual production parameters of the fuel cell as an example, the activation scheme of the present application includes:

[0049] S1: After the fuel cell stack is connected to the stack test platform:

[0050] Open the inlet and outlet valves of the cathode side and anode side of the fuel cell stack, and use nitrogen to purge the dry circuit for 15 minutes to keep the stack dry and replace the nitrogen in the anode and cathode cavities, and close the inlet and outlet valves of the anode and cathode sides;

[0051] S2: open the inlet and outlet electromagnetic valves of the cathode side of the electric pile, air 5L / min is input for 10s, then hydrogen 2L / min is input for 10s, and the cycle is repeated twice, the inlet and outlet valves are closed, the pressure value and the temperature value are recorded, and the pressure and temperature values after 2min form difference values ΔU1 and ΔU2; the air and hydrogen flow ratio is adjusted to make ΔU1 and ΔU2≤5% of the original value

[0052] The inlet and outlet electromagnetic valves of the anode side of the electric pile are opened, air 5L / min is input for 10s, then hydrogen 2L / min is input for 10s, and the cycle is repeated six times, the inlet and outlet valves are closed, the pressure value and the temperature value are recorded, and the pressure and temperature values after 2min form difference values ΔU3 and ΔU4; the air and hydrogen flow ratio is adjusted to make ΔU3 and ΔU4≤5% of the original value

[0053] S3: under the condition of hydrogen and air 2.0 metering ratio constant pressure 50kpa, constant current 1A current is recorded for 3min, and the voltage is recorded.

[0054] S4: the parameters of ΔU1, ΔU2, ΔU3 and ΔU4 are matched, the steps S2 and S3 are repeated, and the voltage difference of the last three cycles is less than 5mv as the judgment of the activation completion mark.

[0055] Obviously, the specific implementation of the present application is not limited by the above-mentioned manner, and various non-essential improvements made by adopting the method concept and technical scheme of the present application are within the protection scope of the present application.

Claims

1. A rapid activation method for fuel cells, characterized in that: Includes the following steps: S1. Arrange the fuel cell on the fuel cell stack test bench and complete the connection; S2, Fuel cell stack initialization; S3. Introduce a preset gas into the cathode and anode, and control the opening and closing of the cathode side inlet and outlet solenoid valves based on the preset pressure difference ΔU1 and temperature difference threshold ΔU2 within the fuel cell stack; control the opening and closing of the anode side inlet and outlet solenoid valves based on the pressure difference ΔU3 and temperature difference threshold ΔU4 within the fuel cell stack. S4. The standard working gas of the battery is introduced into the anode and cathode respectively, and the stack voltage is recorded. S5. Repeat steps S3 and S4 and determine whether activation is complete based on the stack voltage recorded in step S4.

2. The rapid activation method for fuel cells as described in claim 1, characterized in that: In step S2, the fuel cell stack is kept dry by purging with inert gas and the anode and cathode cavities inside the fuel cell stack are filled with inert gas, thereby completing the fuel cell stack initialization.

3. The rapid activation method for fuel cells as described in claim 2, characterized in that: In step S2, the inert gas includes nitrogen. Open the inlet and outlet solenoid valves on the cathode and anode sides of the fuel cell stack, purge with nitrogen for a set time to keep the stack dry and replace the anode and cathode cavities with nitrogen, and then close the inlet and outlet valves on the anode and cathode sides.

4. The rapid activation method for fuel cells as described in claim 1, characterized in that: In step S3, the inlet and outlet solenoid valves on the cathode side of the fuel cell stack are opened, and hydrogen and air are introduced at a fixed pulse ratio before the inlet and outlet solenoid valves are closed. The initial pressure difference ΔU1 and temperature difference threshold ΔU2 within the cathode-side stack were recorded. The air and hydrogen flow rates were adjusted so that ΔU1 and ΔU2 were ≤ 5% of their original values.

5. The rapid activation method for fuel cells as described in claim 1, characterized in that: In step S3, the inlet and outlet solenoid valves on the anode side of the fuel cell stack are opened, and hydrogen and air are introduced at a fixed pulse ratio before the inlet and outlet solenoid valves are closed. The initial pressure difference ΔU3 and temperature difference threshold ΔU4 within the anode-side stack were recorded. The air and hydrogen flow rates were adjusted so that ΔU3 and ΔU4 were ≤ 5% of their original values.

6. A rapid activation method for fuel cells as described in claim 4 or 5, characterized in that: Step S3, which introduces hydrogen and air at a fixed pulse ratio, includes: first introducing air at a set flow rate for a duration of T1, then switching to introducing hydrogen at a set flow rate for a duration of T2, and repeating this cycle multiple times.

7. The rapid activation method for fuel cells as described in claim 1, characterized in that: In step S4, the standard working gas for the battery is introduced into the anode and cathode respectively. This includes replacing the anode and cathode sides with hydrogen and air respectively, and introducing air and hydrogen into the anode and cathode at a stoichiometric ratio of 2.0 and a constant pressure of 50 kPa. The battery stack is controlled to operate under a constant current of 1A, and the voltage V is recorded.

8. The rapid activation method for fuel cells as described in claim 1, characterized in that: In step S5, steps S3 and S4 are repeated with the parameter values ​​of ΔU1, ΔU2, ΔU3, and ΔU4 in the same matching state, and the voltage V recorded in step S4 during each repetition is obtained. 测 .

9. The rapid activation method for fuel cells as described in claim 8, characterized in that: Based on the recorded voltage V measured after each cycle, the activation is considered complete when the difference between V measurements between adjacent cycles is less than a set threshold.

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