抄録
Energy and environmental loads on four types of batteries of lead-acid (PbA), nickel-cadmium (NiCd), nickel-metal-hydride (NiMH) and lithium-ion (Li-ion) batteries were analyzed for high-efficiency usage of electricity using a life cycle assessment method. The net total efficiency was estimated considering loads on the material process such as production, manufacturing and use. This total efficiency was calculated with the ratio of the life cycle discharged energy to the life cycle input energy. The CO2 emission intensity was also analyzed for the electric-load leveling. In case of using the nighttime electricity, the CO2 emission intensity for the battery system decreased to almost the same level for the CO2 intensity of the daytime electricity. In particular, the lithium-ion battery showed the smallest loads. The effects of use conditions for the battery such as the depth of discharge (DOD) and the discharge rate (C rate) were then analyzed. It was clarified that the CO2 emission intensity was varied according to the use condition.
