One-Wire battery monitoring system with applications to on-board charging for electric vehicles

摘要

A novel on-board charge system which utilizes a ''One-Wire'' system for voltage monitoring is discussed and test results obtained using the system are presented. The system consists of a 20 kHz high frequency charger, an algorithm for charging lead-acid batteries with gelled electrolyte, such that gassing is avoided, the control system to implement this charge algorithm and a one-wire battery monitoring system to provide cell/module voltage information to the battery charge controller. Prototype elements of the system have been tested and the system was installed into an EVA Pacer electric vehicle. Charge tests are performed and data taken with the system installed. All elements of the system functioned properly under user conditions. In particular, the charger demonstrated good efficiency, near unity power factor and full programmability. The charge controller functioned reliably and without flaw. The one-wire monitoring system which permits monitoring of cell/module voltages in a battery pack without an extensive conventional wire harness has proven effective and voltage measurements have taken fast enough for control of charging. It was found that for the purpose of voltage monitoring under driving conditions, the system in its present form is too slow.