What is the failure mode of the power lithium battery system?

1, bus failure:

If the bolt is connected, during the later use, the bolt oxidation or vibration causes the bolt to loosen, which will cause a lot of heat at the conductor connection, and in extreme cases will cause the power battery to catch fire. Therefore, most power battery system manufacturers use laser welding at the connection between the core and the core or the connection between the module and the module during the Pack design, or increase the temperature sensor at the connection to avoid the failure of the bus by means of detection.

2, power cell system main circuit connector failure:

The power cell system high voltage wire is connected to the external high pressure system through the connector. The performance of the connector is unreliable, and virtual joints occur under vibration, resulting in high-temperature ablation connectors. In general, connection failure occurs when the connector temperature exceeds 90 degrees. Therefore, in the design of the system, the connector needs to add high-pressure interlocking functions, or attach a temperature sensor to the connector to monitor the connector's temperature at all times to prevent the connector from failing.

3, high-pressure contactor adhesion:

The contactor has a certain number of tether disconnections, and most contactors ablate when the high current belt is closed. The double relay scheme is generally used in the system design, and the control is closed in order to avoid the adhesion of the high-pressure contactor.

4, fuse overflow protection failure:

The type matching of the fuse in the parts of the high voltage system requires comprehensive consideration of which of the gradient breaks first and which of them breaks later. Vibration or external collision extrusion leads to deformation of the power battery, seal failure, and reduced IP rating. Therefore, collision protection of the battery box structure is required during system design.

According to the above failure modes of power battery systems, researchers and battery manufacturers need to improve the safety of lithium battery cores through continuous improvement of processes and technologies. BMS system manufacturers must fully understand the performance of batteries, based on the safety design principles of power cells. Design a safe and reliable battery system, and correct use is the ultimate barrier to ensure battery safety. Users should correctly use the power battery system to prevent mechanical abuse, thermal abuse and electric abuse, and effectively improve the safety and reliability of electric vehicles.

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