Lithium ion battery is widely used in new energy vehicles, given its high energy/power density, extended longevity, and environment friendliness. However, composed of hundreds of lithium ion cells, the battery system is very complex and subject to many safety constraints. Therefore, safety, durability and power output capability of lithium ion batteries must be well managed on board. It is essential for a battery management system (BMS) to guarantee that the lithium ion battery works within safe status, thereby ensuring safety, durability and power output capability of the lithium ion battery system. A typical BMS is composed of sensors, actuators, controllers, etc. The key technologies of the BMS include: sensor and signal synchronization, state estimation of cell and battery pack (state of charge-SOC, state of health-SOH, state of function-SOF, state of energy-SOE, and state of safety-SOS), cell variation identification and balancing, safe charging control, fault diagnosis, etc. Advanced BMS design requires systematic research of battery mechanism and long-time technological accumulation. Basically, performance tests and researches are essential to the characteristics and mechanisms of safety, durability and power output capability of lithium ion battery. Based on deep understanding of the battery performance, semi-empirical and empirical models can be established for cell and battery systems. Furthermore, model-based state estimation and performance optimization algorithms can be developed in BMS integration and design, and the battery system can thus safely work at its optimal status.

management system for lithium-ion battery  /  state estimation  /  fault diagnosis  /  identification of consistency  /  balancing technology  /  safety charging