DEVELOPMENT OF LARGE-SCALE LITHIUM ION BATTERIESFOR ENERGY STORAGE

摘要

Secondary batteries are convenient for electric vehicles and demand-side stationary energy storagedevices that are usually called the disperse energy storage. They should have the capacity of 20 to 45kWh per unit. Lithium ion batteries are most suitable for this purpose, because of their inherent highenergy density and long longevity with potential reliability and safety. Unit cells of the batteries are 300to 500 Wh in capacity, and assembled into a module of 2 to 3 kWh. Four types of batteries have beendeveloped, which are namely called the graphite-coke hybrid/LiNi0.7Co0.3O2 and the Ag-dispersedgraphite/LiMn2O4 (Li-rich) for stationary purpose, and the combined graphite/ LiNi0.55Co0.15Mn0.3O2,and the graphite/LiMn2O4 for electric vehicle purpose. They almost fulfilled their R&D targets, namely120 Wh/kg as the specific energy, 240 Wh/l as the volumetric energy density, and 3500 cycles as thecycle life for stationary use, and 150 Wh/kg, 300 Wh/l, 1000 cycles and 400 W/kg as the power density.Safety tests were conducted in a companion research project.