Trial manufacturing of a large-scale lithium ion battery for power storage

With the aim of developing 1 kWh class lithium ion batteries with long life and high efficiencies, we trial manufactured batteries that were fabricate d using LiCoO2 and natural graphite as cathode and anode active materials, respectively with 1 mol dm(-3) LiPF6 or LiBF4 dissolved in EC/DEC as an ele ctrolyte. The construction of the batteries was based on the results of fun damental research done to elucidate the problems encountered with previous models. We achieved 543 cycles with high efficiencies with the 4th battery, exceeding the initial target of 500 cycles. The life and efficiencies of t he 4th battery exceed those of large-scale lead storage batteries commercia lly available. It was noteworthy that: engineering factors such as uniform impregnation of the electrolyte into the electrode laminates and maintenanc e of homogeneous conditions of laminates by the control of expansion and co ntraction during charge and discharge phases, respectively, were very impor tant for the long life of large-scale lithium ion batteries.