Sanyo Electric Co., Ltd.

Keiichi Tsujioku

Koji Nishio

Yasuhiro Yamauchi

Yuji Yamamoto

Seiji Yoshimura

Satoshi Narukawa

Toshihiko Saito

Toyoji Machida

Yoshihiro Shoji

Nobuhiro Nishiguchi

Kazuro Moriwaki

Tooru Amazutsumi

Mitsunori Hara

Hiyoshi Tamaki

Minoru Fujimoto

A lithium secondary battery comprises a negative electrode having lithium as an active material, a positive electrode comprising a boron-containing lithium-manganese composite oxide as an active material and a nonaqueous electrolyte comprising a solute and a solvent, the boron-containing lithium-manganese composite oxide having an atomic ratio between B and Mn (B/Mn) of 0.01 to 0.20 and an average valence of manganese before charge-discharge of at least 3.80, and the solvent being a mixed solvent containing 5 to 50% by volume of a butylene carbonate. This battery is highly reliable, since the positive electrode active material minimally decomposes and hence the internal resistance minimally increases, even when the battery is continuously charged at a high voltage by mistake.

Lithium secondary battery

A nonaqueous electrolyte battery has a positive electrode, a negative electrode and separator laminate rolled into a spiral electrode unit contained in an external case filled with nonaqueous electrolyte. Battery voltage is between 3.5 V and 5.0 V when charged. A positive electrode supporting member material and the external case are both aluminum. The positive Electrode supporting member is exposed for at least a portion of the outermost winding of the spiral electrode unit, and this exposed supporting member contacts the inner surface of the external case to make an electrical connection.

Nonaqueous electrolyte battery

Growing community of inventors

Sumoto, Japan

Keiichi Tsujioku