Battery Fault of Electric Vehicles
Possible battery pack failures can be categorized into three main groups: battery misuse, connection failures, and sensor failures. Any of these defects can cause heat generation, which, if not detected or tolerated in time, can accelerate the rate of degradation and even lead to thermal runaway and explosion.
1) Battery misuse errors
This failure group includes overcharging, overdischarging, internal short circuit, external short circuit, thermal runaway, etc. that can occur within the battery. Errors in the battery management system or reduced cell capacity can cause overcharging and overdischarging errors. These errors can cause chemical and physical damage to the battery, affecting its performance and safe operation.
An internal short circuit refers to poor insulation between layers inside the battery, while an external short circuit refers to the shorting of the positive and negative terminals. An external short circuit is more dangerous and noticeable than an internal short circuit, which can be ignored in the early stages. However, an internal short circuit can develop into a serious failure after a while.
2) Actuator Abnormality
Faults in this group include connection errors, cooling system errors, controller area network bus errors, etc. Due to the high power requirements of electric vehicles, the battery system usually consists of many battery cells connected in a parallel-series configuration.
Loose connections can reduce available power and cause accidents. Increased resistance in connections can generate heat and affect battery performance. A failure in the cooling system can cause the battery temperature to exceed the allowable temperature range and lead to thermal runaway, one of the serious battery failures.
3) Sensor Errors
Battery Management Systems (BMS) play a key role in the safety, reliability and effective performance of electric vehicles. This unit is responsible for several tasks such as estimating the battery’s State of Charge (SOC) and State of Health (SOH), thermal management, and cell balancing by monitoring the cell voltage, current and temperature.
If these sensors are defective or malfunctioning, it will affect the performance of the BMS and may cause further errors such as: B. Battery misuse errors and serious failures, all of which will reduce the battery life and safety.