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

Abstract Lithium-ion batteries with a combination of a lithium titanium oxide (LTO, Li4/3Ti5/3O4) anode and 4-volt-class cathodes, namely, LiMn2O4 (LMO) and LiNixCoyMn1-x-yO2 (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 °C 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.