Hitachi Chemical Company, Ltd.

Shin-kobe Electric Machinery Co., Ltd.

Tadashi Yoshiura

Takayuki Kimura

Shingo Itoh

Hiroo Nishiyama

Yuichiro Mishiro

Takanori Kajimoto

Manabu Ochida

Youhei Itoh

Sho Hiyama

A lithium-ion battery with high safety is provided. A lithium-ion batteryincludes an electrode group, an electrolyte, and a battery containerthat contains the electrode groupand the electrolyte. The electrode groupis formed by stacking a positive electrode and a negative electrode via a separator. The positive electrode contains a composite oxide of lithium, nickel, manganese, and cobalt as a main positive active material. The negative electrode contains amorphous carbon as a main negative active material. The lithium-ion batteryhas a discharge capacity of 20 Ah or more. The ratio (the value of Y/X) of a volume Y occupied by the electrolyte to a volume X of a void space in the battery containeris 0.65 or more.

Lithium-ion battery

The present invention provides a cylindrical lithium-ion secondary battery. The lithium-ion battery of the present invention has a structure in which the value of B/A is optimized, where the distance between an electrode pole to which strip-form lead pieces are welded, the lead pieces being formed intermittently in the winding direction, which is the longitudinal direction of the belt-like electrodes, and the inner wall of the battery can is represented by A, and the distance between the electrode pole and the wound electrode group is represented by B, in order to secure an exhaust passage for the gas generated upon occurrence of an abnormality in the battery.

Growing community of inventors

Tokyo, Japan

Tadashi Yoshiura