Nickel cadmium battery evaluation, modeling, and application in an electric vehicle

A battery testing facility was set up in the battery evaluation laboratory. This system includes a set of current regulators which were fabricated in the UMASS. Lowell labs and a PC based data acquisition system. Batteries were charged or discharged at any rate within system ratings, and data including battery voltage, current, temperature and impedance were stored by a PC. STM5.140 type nickel-cadmium electric vehicle batteries were subjected to various test procedures using the battery testing facility. The results from these tests were used to determine battery characteristics. An electrical component battery model was also developed using the test data. The validity of the battery model was verified through experimental testing, and it was found to be accurate. Additionally, improved battery charging algorithms were developed which resulted in significant improvements in battery efficiency. Electric car operation with STM5.140 type of batteries was evaluated. Realistic road test data were analyzed experimentally and using the battery model. No battery abuse was found under EV driving conditions. The performance of the STM5.140 battery under abuse conditions was evaluated and it was found that it performs reasonably well under all abuse conditions tested. The model and test methodologies may be incorporated into complete electric vehicle models in order to assist in the design and operation of current and future electric vehicles.