A Lithium-ion Battery Protection Analog Front-end Charge And Discharge Control And Drive

Lithium-ion (Li+) battery has been widely and successfully used because of its many outstanding performances: large energy density, low self-discharge rate and high single cell voltage etc.However, due to its own structure characteristics, lithium-ion battery needs delicate management and protection to maximize its functionality and safety. Especially for the system containing plural battery cells, since the battery structure is small but has a high output (large current, high voltage), a charge/ discharge abnormality may take place easily, which made the need of more effective, accurate battery management system to prevent that.A 2-, 3-, or 4-cell lithium-ion battery analog front-end (AFE) protection IC is studied in this thesis. It is designed to work with a SBS-compliant gas gauge IC to form a complete battery management unit.This paper introduces the working principles of the AFE protection IC in the battery management system, including how to realize over-voltage and under-voltage protection, over-current protection and over-temperature protection function. The charging and discharging control is studied and the corresponding drivie circuit is designed. One kind of charge pump adaptive with wide range input voltage and with very small standby current is proposed; a precharge drive circuit is also proposed. After detailed analysis of above circuits, HSPICE simulation result is given to prove the design work properly.