GB/T 38914-2020Evaluation method for lifetime of proton exchange membrane fuel cell stack in vehicle application (English PDF)

3.1 Idling current

The output current of the tested fuel cell stack corresponding to the fuel cell stack of the on-board fuel cell system under idling conditions. Under this current, the fuel cell stack can maintain the fuel cell system itself for a certain period of time, without outputting power externally.

3.2 Rated current

The output current of the tested fuel cell stack corresponding to the fuel cell stack of the on-board fuel cell system under the rated operating conditions.

Under this current, the fuel cell stack can maintain operation for a certain period of time.

3.3 Reference current condition

Working conditions based on a specific current in the evaluation of the lifetime of fuel cell.

3.4 Operation mode cycle

The change history of operating conditions of the fuel cell stack during continuous operation from startup to shutdown of the tested fuel cell stack corresponding to the on-board fuel cell system.

4.1 Test object

The test object is generally a single fuel cell stack or a combination of multiple fuel cell stacks. The tested cell stack, internal membrane electrodes and bipolar plates have the same structural dimensions and materials as the actual fuel cell stack.

4.2 Test platform and test object installation

The main measuring devices and measuring accuracy are as shown in Table 1.

4.3 Test environment and basic requirements

The specified test environmental conditions are as follows. the altitude does not exceed 1000 m; the ambient temperature is 5 °C ~ 40 °C; the laboratory and outdoor shall be kept ventilated.

Basic requirements. The purity of the hydrogen used shall not be less than 99.97%, which meets the requirements of GB/T 37244-2018.

4.4 Special requirements

The test evaluation of the fuel cell stack shall be carried out in accordance with the following provisions.

5.1 General

It is required to complete the following tests in sequence. It shall not adjust the test sequence. Unless otherwise specified. The loading and unloading process is generally completed according to the control method required by the client.

When an unexpected shutdown occurs, the fuel cell stack's voltage shall be reduced to below 0.3 V in each segment in time.

5.2 Activation, testing and stability assessment

5.2.1 Activation of fuel cell stack

Activate the fuel cell stack according to the method specified by the client.

5.2.2 Test of fuel cell stack performance and determination of current

parameters

5.2.3 Assessment of fuel cell stack stability and determination of initial

voltage V0 Perform 100 h operation according to Figure 2 and Table 2. The operating condition spectrum is as follows. start and stop 1 time per hour, apply load 27 times, idle speed 21 min, rated working condition 18 min. Every 4 hours of operation of fuel cell stack, shut down for 1 hour.

5.3 Test based on working conditions

5.3.5 Start-stop conditions

Add 7 times of start-stop in the middle of the variable load test cycle. Split it into 8 stages to complete; every about 30 minutes is a small "start-variable load-stop" cycle, as shown in Figure 6.A complete cycle of testing includes 8 start-stop, 217 loading, rated operating time of 738 s, idle time of 3680 s, of which maintain 90 s after the last loading to the reference current condition, record of voltage. Table 6 is the operating procedures of test cycle.