Patent ID: 9172261
Filing Date: 2015-10-27
Classification: H02J

Abstract:
1. A battery pack comprising: a secondary battery including a plurality of cell blocks; a temperature detecting element configured to detect a temperature of each of the plurality of cell blocks; a measuring section configured to detect a voltage, a current, and an internal resistance, of the secondary battery; a controller configured to monitor the voltage and the current of the secondary battery and output a request signal indicative of a charge condition to charge the secondary battery in accordance with the charge condition which is set; a charge and discharge control switch configured to prevent overcharge and overdischarge; a protection circuit configured to monitor voltages of the plurality of cell blocks; and a memory which registers an initial internal resistance of the secondary battery based on a variation of initial internal resistance values for each of the cell blocks being within a predetermined range, wherein the initial internal resistance of the secondary battery is a resistance before an initial use of the secondary battery corresponding to the initial internal resistance values, wherein the controller obtains a maximum internal resistance among internal resistances of the plurality of cell blocks, calculates a deterioration coefficient by a ratio of the maximum internal resistance to the initial internal resistance of a cell block exhibiting the maximum internal resistance, and changes the charge condition in accordance with the deterioration coefficient, and wherein the charge condition includes a charging current value in constant-current charge, and a new charging current value is set to a value equal to an initial charging current multiplied by the deterioration coefficient.