Panasonic Ev Energy Co., Ltd.

Teruyoshi Egoshi

Yusai Murakami

Norito Yamabe

Masahiro Takada

There is provided a battery pack system with estimation accuracy of a remaining capacity of a secondary batter enhanced. A current accumulation coefficient correction sectioncalculates a correction amount &#x3b1; with respect to a current accumulation coefficient k in accordance with a battery electromotive force Veq from an electromotive force calculation section. A remaining capacity calculation sectionestimates a remaining capacity SOC by current accumulation, based on the current accumulation coefficient k calculated from a correction amount &#x3b1;, and a charging efficiency &#x3b7; based on a currently estimated remaining capacity calculated by a charging efficiency calculation section

Method and apparatus for estimating remaining capacity of secondary battery

There is provided a battery pack system that allows an output limit during short-time discharging and long-time discharging of a secondary battery, and limits the output appropriately upon request of a vehicle. An output limiting sectionis provided for changing a limit value of output electric power from the secondary battery when voltage data V (n) from a voltage measuring sectionreaches a predetermined discharging termination voltage. The output limiting sectionhas short-time output information (Pp) for allowing short-time discharging of the secondary battery and normal output information (Pn) for allowing long-time discharging of the secondary battery, and sets a first discharging termination voltage (V) during short-time discharging to be lower than a second discharging termination voltage (V) during long-time discharging.

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Toyohashi, Japan

Teruyoshi Egoshi