GB/T 46990-2025Electrical performance requirements and test methods for electric double-layer capacitors used in hybrid electric vehicles (English PDF)

4.1 Appearance, Polarity Marking, Mass and Dimensions

4.1.1 Appearance

The capacitor shall be inspected in accordance with 5.2.1.The appearance shall be free from deformation and cracks, and the surface shall be flat, dry, and free from electrolyte overflow traces.

4.1.2 Polarity marking

The capacitor shall be inspected in accordance with 5.2.2.The terminal polarity marking shall be clear, complete and accurate.

4.1.3 Mass and dimensions

The capacitor shall be inspected in accordance with 5.2.3.The mass and dimensions of the capacitor shall conform to the product technical specifications provided by the manufacturer.

4.2 Capacitance, Internal Resistance and Maximum Power Density

4.2.1 Capacitance

The capacitor shall be tested in accordance with 5.3.4.The electrostatic capacitance shall be

100% ~ 120% of the nominal capacitance.

4.2.2 Internal resistance

The capacitor shall be tested in accordance with 5.3.5.The internal resistance shall not exceed its nominal internal resistance.

4.2.3 Maximum power density

The capacitor shall be tested in accordance with 5.3.6.The maximum power density shall not be less than its nominal value.

4.3 Voltage Maintenance Characteristics

The capacitor shall be tested in accordance with 5.4, and the voltage between the positive and negative terminals shall not be lower than 80% of its rated voltage.

4.4 Energy Efficiency

The capacitor shall be tested in accordance with 5.5, and the energy efficiency shall not be lower than 90%.

5.1 Environmental Conditions

Unless otherwise specified, the test shall be conducted in an environment with a temperature of

25 °C ± 5 °C, a relative humidity of 10% ~ 90%, and an atmospheric pressure of 86 kPa ~ 106 kPa.

5.2 Appearance, Polarity Marking, Mass and Dimensions

5.2.1 Appearance

Under good lighting conditions, visually inspect the appearance of the capacitor.

5.2.2 Polarity marking

Use a voltmeter to detect the polarity of the capacitor and visually inspect the polarity marking for correctness and clarity.

5.2.3 Mass and dimensions

Before testing, the capacitor shall be fully charged and fully discharged, and then allowed to rest at room temperature or the relevant specified temperature for 2 to 6 hours. If necessary, the charge-discharge process may be repeated multiple times, until the capacitance and internal resistance stabilize. Connect the capacitor sample to be tested to the test equipment.

NOTE. the resting time is determined with reference to the thermal equilibrium time in Appendix

B.

5.3.3.2 Test equipment setup

Unless otherwise specified, the test equipment shall be set up as follows.

a) Perform constant current charging. The current value can be calculated using UR/38RN.

At this current, the capacitor can be charged with 95% charging efficiency based on the nominal internal resistance RN. The constant current value or charging efficiency can be changed through negotiation between the customer and the manufacturer. The concept of 95% charging/discharging efficiency is given in Appendix C. When the rated value of the capacitor’s internal resistance is uncertain, the measurement current can be set in accordance with the steps described in Appendix D.

b) Set the maximum voltage for constant current charging to UR.

c) Set the duration of constant voltage charging TCV to 300 s.

d) Set the current value for constant current discharging. This value is calculated based on 95% discharging efficiency of RN using UR/40RN. The constant current value or discharging efficiency can be changed through negotiation between the customer and the manufacturer.

e) Set the cut-off voltage for constant current discharging to 0.4UR and the resting time

Trest to 1 s.

f) Set the sampling interval to 10 ms or less.

5.3.3.3 Test

At room temperature, in accordance with the settings in 5.3.3.2, as shown in Figure 2, charge and discharge the sample in the following order and measure the voltage between the positive and negative terminals of the capacitor.

a) Charge at constant current to UR;

b) Charge at constant voltage of UR for 300 s;

c) Discharge at constant current to 0.4UR;

d) Let stand for 1 s;

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