Charging batteries rapidly and frequently, e.g. for electric vehicle - ascertaining battery charge, internal resistance and gas formation voltage in test cycle before charging from external current source

摘要

Charging batteries involves using an external current source which is controlled to apply a defined charge voltage to the battery. The battery's state of charge, internal resistance and output voltage are determined before charging begins in a test cycle (31) involving increasing a test current whilst the voltage is continuously monitored. A gas formation voltage (29) derived from the voltage curve inversion point (20) is stored and the test current reduced, pref. to null. The voltage is then monitored for a defined period. A controlling charge current is then applied to achieve the gas formation voltage or lower. The test cycle is repeated at defined intervals during subsequent charging. ADVANTAGE - Rapid, frequent charging with long operating life achieved.