High Energy Rechargeable Li-S Cells for EV Application. Status, Remaining Problems and Solutions

摘要

Electric Vehicles (EVs) to achieve driving ranges exceeding 300 miles (500 km) require cell-level specific energy of 550 Wh/kg (1). For consumer acceptance, cycle life must surpass 1000 cycles. With theoretical specific energy of 2500 Wh/kg and theoretical energy density of 2600 Wh/1, the Li-S system is a prime candidate for future EV applications. Sion Power Corporation is working aggressively on realizing the impressive potential of the Li-S system for EV applications. Sion Power's current baseline, 2.8 Ah, Li-S cell has a specific energy of 350 Wh/kg, the highest value reported for any practical rechargeable system. Battery packs comprised of Sion's baseline Li-S cells substantially increased the flight durations of Unmanned Aerial Vehicles (UAVs) (2). With optimized cell designs, specific power exceeding 1500 W/kg, at continuous discharge, and over 3000 W/kg, for 10 seconds high current pulses, have been realized (3). Table 1 compares Sion's baseline 2.8 Ah cell to USABC long term goals for EV application. It is seen that, with the exceptions of cycle life and upper operating temperature, Sion cells meet, or exceed all requirements.