Lithium battery pack system integrated failure mode

1. Failure of the bus:

If it is a bolted connection, the bolts will oxidize and fall in the later use process, or the vibration will cause the bolts to loosen, which will generate a lot of heat at the conductor connection, and in extreme cases, it will also cause conductor damage. The power battery is on fire. Therefore, most power battery system manufacturers use spot welding in battery-to-battery or module-to-module connections when designing battery packs, or add temperature sensors to the connection to prevent busbar failure.

 2. The main circuit connector of the power battery system fails:

The high-voltage line of the power battery system is connected to the external high-voltage system through a connector. The performance of the connector is unreliable, and a virtual connection occurs under vibration, resulting in high-temperature ablation of the connector. Generally, connector failure will occur if the connector temperature exceeds 90 degrees. Therefore, during system design, the connector needs to add a high-voltage interlock function, or a temperature sensor is attached to the connector to monitor the temperature of the connector at all times to prevent the failure of the connector.

3. Sticky high voltage contactor:

The contactor is opened a certain number of times under the load, and when the high-current load is closed, most of the contactors are ablated. In the system design, the double relay scheme is usually used, and in order to avoid the stuck of the high-voltage contactor, the control device is in a closed state.

4. Fuse overcurrent protection failure:

The selection and matching of fuses in high-voltage system components requires a comprehensive consideration of which gradient is broken first and which gradient is broken. Vibration or external shock and compression can cause deformation of the power battery, seal failure, and reduce IP rating. Therefore, it is necessary to consider the collision protection of the battery box structure when designing the system.