CONDITION MONITORING FOR LIFE EXTENSION OF FAST, HIGH DENSITY BATTERY CHARGING

摘要

Fast, high density battery charging has become an important issue due to recent advances in technology, such as the Electric Vehicle (EV). Batteries that were once charged in a few hours are now being charged in a matter of minutes. Without proper control, these vigorous charge regimes can substantially shorten the life of the battery. A number of techniques, such as pulse charging, have been explored to limit aging that occurs during the gassing phase of the charge. In many cases, the pulse used is varied depending on the battery's State-of-Charge (SOC). Determination of SOC is therefore very important to the success of the pulse charging routine. By identifying the gassing point and SOC of the cell, charge conditions can be adjusted so that the maximum amount of energy can be returned to the battery before premature aging begins. This can be accomplished by monitoring the conditions of the cell as charging progresses. Condition monitoring in batteries has traditionally been limited to external signals, such as voltage, current, and temperature. However, monitoring physically related signals, such as cell impedance, provides a better assessment of the condition and health of the battery, and therefore provides a better means for controlling charging. This paper will focus on applying developed model-based diagnostics for assessment of SOC and State-of-Health (SOH) to improve fast charging performance of secondary batteries.