GB/T 36972-2018Lithium-ion battery for electric bicycle (English PDF)

5.1 General Principles

The electrical performance of the battery packs shall meet the requirements for electric bicycles to operate on public roads.

The safety requirements for cells and battery packs shall comply with the requirements of GB

43854.

5.2 Performance Requirements for Cells

5.2.1 I2(A) discharge

When tested in accordance with the test method described in 6.3.1, the cell discharge capacity shall reach the rated capacity.

5.2.2 2I2(A) discharge

When tested in accordance with the test method described in 6.3.2, the cell discharge capacity shall not be less than 95% of the rated capacity.

5.2.3 Cycle life

When tested in accordance with the test method described in 6.3.3, the cell cycle life shall not be less than 1,200 cycles.

5.3 Performance Requirements for Battery Packs

5.3.1 I2(A) discharge

When tested in accordance with the test method described in 6.4.1, the battery pack discharge capacity shall reach the rated capacity.

5.3.2 2I2(A) discharge

When tested in accordance with the test method described in 6.4.2, the battery pack discharge capacity shall not be less than 95% of the rated capacity.

5.3.3 Low temperature discharge

When tested in accordance with the test method described in 6.4.3, the battery pack discharge capacity shall not be less than 80% of the rated capacity.

5.3.4 High temperature discharge

When tested in accordance with the test method described in 6.4.4, the battery pack discharge capacity shall not be less than 95% of the rated capacity.

5.3.5 Charge retention and recovery Capability

When tested in accordance with the test method described in 6.4.5, the battery pack charge retention capability shall not be less than 85% of the rated capacity, and the charge recovery capability shall not be less than 92% of the rated capacity.

5.3.6 High temperature charge retention and recovery capability

When tested in accordance with the test method described in 6.4.6, the battery pack high temperature charge retention capability shall not be less than 85% of the rated capacity, and the high temperature charge recovery capability shall not be less than 90% of the rated capacity.

5.3.7 Charge recovery capability after long-term storage

When tested in accordance with the test method described in 6.4.7, the battery pack discharge capacity shall not be less than 95% of the rated capacity.

5.3.8 Cycle life

When tested in accordance with the test method described in 6.4.8, the battery pack cycle life shall not be less than 800 cycles.

5.3.9 Internal resistance

When tested in accordance with the test method described in 6.4.9, the internal resistance of the battery pack shall not exceed the value specified by the manufacturer (the internal resistance information shall be marked on a suitable carrier).

5.3.10 Low temperature charge capacity

When tested in accordance with the test method described in 6.4.10, the battery pack charge capacity shall not be less than 80% of the rated capacity.

NOTE. applicable to battery packs for which the manufacturer claims a charging temperature below 0 °C.

5.3.11 Low temperature cycle life

When tested in accordance with the test method described in 6.4.11, the battery pack cycle life shall not be less than 400 cycles.

NOTE. applicable to battery packs for which the manufacturer claims a charging temperature below 0 °C.

6.1 Test Conditions

6.1.1 Environmental requirements

Unless otherwise specified, the test shall be conducted under the following conditions.

Temperature. (20 ± 5) °C, relative humidity. not greater than 85%, atmospheric pressure. 86 kPa ~ 106 kPa.

6.1.2 Requirements for measuring instruments and equipment

The accuracy of measuring instruments and equipment shall not be lower than the following requirements.

a) Voltage measuring device. ± 0.5%;

b) Current measuring device. ± 0.5%;

c) Temperature measuring device. ± 2 °C;

d) Time measuring device. ± 1 s;

e) Dimension measuring device. ± 1 mm;

f) Mass measuring device. ± 0.5%.

6.2 Sample Preparation

6.2.1 Standard cell charging

Charge in accordance with the charging method provided by the manufacturer. If the manufacturer does not provide a charging method, the cell shall be charged using the following method.

Before charging, discharge the cell at a constant current of I2(A) to the cut-off voltage. Under a test environment of (23 ± 2) °C, charge at 0.4I2(A). When the cell terminal voltage reaches the limited charge voltage, switch to constant voltage charging, until the charge current is less than or equal to 0.04I2(A).

6.2.2 Standard battery pack charging

Charge in accordance with the charging method provided by the manufacturer. If the manufacturer does not provide a charging method, the battery pack shall be charged using the following method.

Before charging, the battery pack shall be discharged at a constant current of I2(A) to the cut- off voltage. Under a test environment of (23 ± 2) °C, charge at 0.4I2(A). When the terminal voltage of the battery pack reaches the limited charge voltage, switch to constant voltage charging, until the charge current is less than or equal to 0.04I2(A).

6.3 Cell Performance Test

6.3.1 I2(A) discharge

Under a test environment of (23 ± 2) °C, after the cell is charged in accordance with the method described in 6.2.1, let it stand for 0.5 hours, and then, discharge at a constant current of I2(A) to the discharge cut-off voltage. Record the cell discharge time and calculate the discharge capacity.

The above-mentioned cell discharge capacity test shall be repeated 3 times. When the discharge capacity meets the requirements of 5.2.1 in one of the tests, the test of this item can be terminated.

6.3.2 2I2(A) discharge

Under a test environment of (23 ± 2) °C, after the cell is charged in accordance with the method described in 6.2.1, let it stand for 0.5 hours, and then, discharge at a constant current of 2I2(A) to the discharge cut-off voltage. Record the cell discharge time and calculate the discharge capacity.

6.3.3 Cycle life

Under a test environment of (23±2) °C, after the cell is charged in accordance with the method described in 6.2.1, let it stand for 0.5 hours, and then, discharge at a constant current of I2(A) to the discharge cut-off voltage. Record the cell discharge time and calculate the discharge capacity.

After one charge-discharge cycle test, let the cell stand for 0.5 to 1 hour before the next charge- discharge cycle is performed. This process continues until two consecutive discharge capacities are below 60% of the rated capacity, at which point the test of this item can be terminated. The last two charge-discharge cycles are not included in the total number of cycles.

6.4 Performance Test of Battery Packs

6.4.1 I2(A) discharge

Under a test environment of (23±2) °C, after the battery pack is charged in accordance with the method described in 6.2.2, let it stand for 0.5 hours, and then, discharge at a constant current of I2(A) to the discharge cut-off voltage, or when battery pack protection is activated. Record the battery pack discharge time and calculate the discharge capacity.

The above-mentioned battery pack discharge capacity test shall be repeated 3 times. When the discharge capacity meets the requirements of 5.3.1 in one of the tests, the test of this item can be terminated.

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