Sanyo Electric Co., Ltd.

Takashi Hosokawa

Kyohei Kobayashi

Naotake Yoshida

Yu Matsui

Takafumi Hosokawa

Shuji Ogawa

A decrease in energy density of a battery is suppressed, and the occurrence of internal short circuit between a positive plate and a negative plate located at the innermost circumference of a curved portion of a flat electrode assembly, where the curvature of the curved portion is greatest, is suppressed. In a nonaqueous electrolyte secondary battery including a flat wound electrode assembly (), the electrode assembly () has a pair of curved portions (A,B) located at either end and a flat portion () located between the pair of curved portions. In at least one of the curved portions, at least two layers of a second electrode plate are disposed on an inner side of a curved portion of a first electrode plate located at an innermost circumference.

Non-aqueous electrolyte secondary battery

A battery pack includes a battery unit including rectangular secondary batteries, each including a sealing plate and positive and negative electrode terminals attached to the sealing plate; a bus bar that connects the rectangular secondary batteries together in parallel; an insulating plate disposed between the sealing plates of the rectangular secondary batteries and the bus bar; and a short-circuit breaking portion that interrupts an electric conduction path between the rectangular secondary batteries connected in parallel by allowing each sealing plate to bulge outward in response to an internal pressure rise of the battery to push up the insulating plate and the bus bar. A portion of each sealing plate that bulges most protrudes outward by greater than or equal to 1.5 mm from an outer peripheral edge of the sealing plate when a pressure in the corresponding rectangular secondary battery reaches the operating pressure of a gas release valve.

Growing community of inventors

Hyogo, Japan

Takashi Hosokawa