The Battery Pack 'EOL' Test Method

Insulation resistance test

Turn off the BMU insulation monitoring function and use the Hipot tester to measure the insulation resistance between the main positive, main, and negative and charging positive of the battery pack and the box, and the resistance value should meet the requirements.

AC and DC withstand voltage test

Turn off the BMU insulation monitoring function, and use the Hipot tester to perform the following tests on the battery pack main positive, main and negative and charging positive chassis:

• Hipot is positively connected to the battery pack and positive and negative to the chassis.

• Hipot is positively connected to the battery pack negative and negative connection to the chassis.

• Hipot is positively connected to the charging positive and negative connection to the chassis.

CAN termination resistance test

The multifunction multimeter is enabled via EOL software to measure the resistance value of the CAN port.

Insulation testing function test

By changing the insulation resistance values of battery HV+ and HV- to ground (connected to 1000kΩ, 500kΩ, 100kΩ), read the insulation resistance and alarm status reported by the BMS.

Vehicle communication function test

When the Keyon is closed, connect the vehicle CAN, and check whether the total voltage, current, maximum and minimum voltage of the battery pack is normal through the EOL host computer software.

Internal communication function test

When the Keyon is closed, connect the internal CAN and check whether the cell temperature and cell voltage of the battery pack are normal through the EOL host computer software.

Charging communication function test (fast charging)

• Simulate the signal of charging gun and charger according to the national standard.

• Handshake between the charger and BMS through analog messages.

• Measure the charging relay 12V+ output voltage.

Total voltage accuracy test

The detected value of the output voltage of the battery system is compared with the total voltage acquisition value of BMS and the accumulated value of the monomer voltage.

Open circuit voltage test

The charging relay is closed via EOL software, and the port voltage is measured with a multifunction multimeter.

Charge and discharge circuit test

The specified (main/main/negative, charging) relay is closed and disconnected by BMS, and the multi-function multimeter is used to detect the port voltage value when the relay is closed and disconnected, and the normal voltage value indicates the normal operation of the charging and discharging circuit.

Pre-charge relay on-off test

The pre-charge relay and the charging relay are closed sequentially by BMS, and the multi-function multimeter is used to detect the port voltage values U1, U2, and U1/U2 of the battery pack in the two states to meet the requirements.

Heating circuit resistance test

Use a multi-function meter to detect the resistance of the heating plug connector.

High voltage interlock

The on-off of the high-voltage interlocking signal line is controlled by EOL, and the corresponding status of the BMS is read through CAN communication.

About Semco - Established in 2006, Semco Infratech has secured itself as the number 1 lithium-ion battery assembling and testing solutions provider in the country. Settled in New Delhi, Semco gives turnkey solutions for lithium-ion battery assembling and precision testing with an emphasis on Research and development to foster imaginative, future-proof products for end users.

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