GB/T 23751.2-2017Micro fuel cell power systems -- Part 2: Performance test methods (English PDF)

4.3 Measuring instruments

4.3.1 General

Measuring instruments shall be determined according to the required accuracy and the range of the measured value. Measuring instruments shall be calibrated periodically to maintain the level of accuracy specified in 4.2. With reference to ISO/IEC 17025, calibration information shall be described in the test report. Instruments for measuring voltage and current shall be capable of continuously recording values throughout the measurement process.

4.3.2 Voltage

The accuracy specified in 4.2 above shall be guaranteed. The internal resistance of the voltage measuring instrument shall be greater than or equal to 1 Mohm.

4.3.3 Current

The accuracy specified in 4.2 above shall be guaranteed.

4.3.4 Time

The time measuring instrument shall have an accuracy of ±1 s/h or higher, so as to ensure the measurement accuracy specified in 4.2.

4.3.5 Mass

The accuracy specified in 4.2 above shall be guaranteed. The measurement of mass shall be carried out in accordance with relevant national standards, industry norms or norms of relevant organizations.

4.3.6 Temperature

The accuracy specified in 4.2 above shall be guaranteed. Recommended instruments for direct measurement of ambient temperature are:

a) Thermocouple with sensor; or b) Resistance thermometer with sensor.

4.3.7 Humidity

The accuracy specified in 4.2 above shall be guaranteed. Refer to the requirements of

ISO 4677-1 and ISO 4677-2 for the measurement of ambient humidity.

4.3.8 Pressure

The accuracy specified in 4.2 above shall be guaranteed. The measurement of pressure shall be carried out in accordance with relevant national standards, industry norms or norms of relevant organizations. If neither is available, the relevant organization shall create a stress measurement standard or specification for this performance test.

4.3.9 Vibration frequency

The accuracy specified in 4.2 above shall be guaranteed. Refer to the requirements of

GB/T 2423.10 for the vibration frequency.

4.3.10 Volume

The accuracy specified in 4.2 above shall be guaranteed.

5.1 Test procedures

Each test shall be performed on 3 samples. The conditioning of samples shall be carried out at least 2 h before the start of the test, so as to adjust the sample to meet the test environmental conditions; the test shall be started immediately after conditioning.

Unless otherwise specified, the micro fuel cell power system shall be connected to the voltmeter and load specified by the manufacturer, so that it can operate at rated power or rated current; the measurement shall last for 1 h or according to the time specified by the manufacturer, so as to observe characteristics of the micro fuel cell power system in actual operation. Throughout the measurement process, data shall be recorded at the sampling frequency specified by the manufacturer. The reported test measurement value shall be the average of the average measurement values of 3 samples, wherein the average measurement value of each sample is the average value of the recorded data of the sample. These tests can be performed sequentially using one set of samples, or simultaneously using different sets of samples. Electrical parameter measurements shall be taken at the power interface.

5.2.4 Power generation test under low temperature and high temperature

conditions a) The purpose of this test is to confirm the performance of the micro fuel cell power system under low temperature and high temperature conditions.

b) The test temperature shall be the minimum and maximum operating temperature specified by the manufacturer. At the beginning of the test, the rechargeable battery or capacitor (optional) shall be fully charged, and the sample's internal reservoir or fuel container shall also be full. The sample shall be subjected to conditioning under the test temperature conditions in accordance with the provisions of 5.1, and then the output voltage shall be measured. The temperature of the test, the load connected and the duration of measurement shall be recorded in the test report.

5.2.5 Power generation test under low humidity and high humidity conditions

a) The purpose of this test is to confirm the performance of the micro fuel cell power system under low humidity and high humidity conditions.

b) The humidity for the test shall be specified by the manufacturer at a humidity level below 20% relative humidity and a humidity level above 80% relative humidity. At the beginning of the test, the rechargeable battery or capacitor (optional) shall be fully charged, and the sample's internal reservoir or fuel container shall also be full. The sample shall be subjected to conditioning under the test humidity in accordance with the provisions of 5.1, and then the output voltage shall be measured. The humidity of the test, the connected load and the measurement time shall be recorded in the test report.

5.2.6 Altitude test

a) The purpose of this test is to confirm the performance of the micro fuel cell power system under reduced atmospheric pressure conditions.

b) The test pressure shall be 680 -10 kPa, and the air pressure shall be as close to 68 kPa as possible. At the beginning of the test, the rechargeable battery or capacitor (optional) shall be fully charged, and the sample's internal reservoir or fuel container shall also be full. The sample shall be regulated under the test pressure in accordance with the provisions of 5.1, and then the output voltage shall be measured. The test pressure, the connected load and the measurement time shall be recorded in the test report.

Note: 68 kPa is the minimum standard pressure in the aircraft cabin.

5.3 Fuel consumption test

a) The purpose of this test is to measure the fuel mass provided by the fuel container and consumed by the micro fuel cell power system when the micro fuel cell power system operates continuously under the conditions of rated current or rated power.

b) The micro fuel cell power system shall operate at rated current or rated power. If it operates at rated current, the overall fuel consumption, the voltage of the micro fuel cell power system and the duration of power generation shall be measured in accordance with the provisions of 5.1; if it operates at rated power, the overall fuel consumption and the duration of power generation shall be measured. The overall fuel consumption shall be measured in terms of the mass or volume of fuel consumed during the electrical measurement. During the electrical measurements, the system shall run continuously for at least 2 h in steady state.

If it is desired or required to increase the accuracy of the measurement, during the measurement, the sample can run for a longer period of time than that specified by the manufacturer. The fuel consumption per unit time and the electricity generated per unit fuel quantity can be calculated according to the following formula:

Fuel consumption rate:

Fuel consumption per hour (g/h or mL/h) =

Electric energy generated per unit amount of fuel (Wh/g or Wh/mL) =

Where:

P = U × I (running at rated current);

I – rated current;

U – average value of the measured voltage.

Or

P – rated power (running at rated power);

h – hours of electricity generation.

The specifications of the fuel shall be recorded in the test report.

5.4 Mechanical durability test

5.4.1 Drop test

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