Battery pack

Abstract

A battery pack includes a secondary cell, a selection unit, a judging unit, an elapsed time period comparing unit, and a control unit. The selection unit selects either a first operation state or a second operation state. The control unit controls the selection unit to switch from the first operation state to the second operation state when the elapsed time period is longer than a predetermined time period. The control unit also controls the selection unit to switch from a second operation state to a first operation state either (a) when judged as being in an used state by the judging unit while the second operation is selected (b) when a voltage of the second cell becomes equal to or less than a second voltage threshold value which is smaller than a first voltage threshold value while the second operation state is selected.

Description

technical field [0001] The invention relates to batteries comprising, for example, lithium-ion accumulators. Background technique [0002] Secondary batteries such as lithium ion secondary batteries are compact in size and light in weight, and have high energy density, high output, and the like. Therefore, secondary batteries are widely used as power sources for application devices such as digital cameras, mobile phones, portable PCs, and camcorders (short for camera and recorder). Lithium-ion secondary batteries are used by repeated discharging and charging, but if the battery is left in a fully charged state or near a fully charged state, battery performance tends to decrease and battery life tends to be shortened. In particular, storage conditions such as being at a high temperature and for a long time lead to significant deterioration of the battery. [0003] For example, if charge and discharge are repeated in the following manner: First, charge the lithium-ion batter...

AI Technical Summary

Problems solved by technology

Thus, if a battery pack with accumulators, especially lithium-ion accumulators, is placed in a state of

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