High-power and long-life lithium-ion batteries using lithium titanium oxide anode for automotive and stationary power applications

摘要

Lithium-ion batteries with a combination of a lithium titanium oxide (LTO, Li_(4/3)O_4) anode and 4-volt-class cathodes, namely, LiMn_2O_4 (LMO) and LiNi_xCo_yMn_(1-x-y)O_2 (NCM) cathode, have been developed for automotive and stationary power applications. The 3 Ah-class LTO/LMO cell for high-power applications had a high output power density of 3600 W kg~(-1) for 10 s pulse. High-rate full cycling tests at 10 C rate exhibited a high capacity retention of 95% after 30000 cycles. The capacity retention after 15 years at 35 ℃ in the calendar life tests is predicted to be 93%. Such a high-power and long-life performance of LTO/LMO cell is suitable for not only hybrid electric vehicle (HEV) but also idling-stop system (ISS) applications. The 20 Ah-class LTO/NCM cell with an energy density of 90 Wh kg~(-1) exhibited a power density of 2200 W kg~(-1). The storage life for floating charge at 100% state of charge (SOC) and the full cycle-life at 3 C rate are predicted to be 10 years at 45 C and 10,000 cycles, respectively. It was demonstrated that the LTO/NCM cells have an excellent balance of high-power, high-energy, low-temperature, and long-life performance for not only electric vehicle (EV) but also plug-in hybrid electric vehicle (PHEV) and stationary power applications.