Abstract: Cells of 25 Ah with mass of 850 g were designed and tested with LiFePO4 (LFPO) as cathode material according to electrical vehicle demands. Discharges of different rates , cycles tests and abuse tests were adopted to certify that the cells have a discharge capacity of 26 Ah at 1 C rate and a high-rate capacity retention of 98% even at 6 C rate (150 A). The voltage at 50% SOC (state of charge) is about 3.0 V when discharged at 6 C rate. The capacity retention of 25-Ah cells is about 90% after 1 700 cycles. All the abuse tests on 25-Ah cells were carried out based on “Electrical Energy Storage System Abuse Test Manual for Electric and Hybrid Electric Vehicle Applications” suggested by U.S. Department of Energy FreedomCAR & Vehicle Technologies Program with satisfactory results. The 16-kWh EV battery units each assembled by 2 parallel, 102 series connections using these batteries have been delivered to Shanghai Automotive Industry Corporations.

Key words: lithium ion battery, electric vehicle (EV), LiFePO4