Battery control device and battery system

A battery control device comprising:

• a control unit which controls a battery pack having a plurality of single cells connected therein;
• a voltage measurement unit which measures voltage between terminals of the single cells or the battery pack;
• a current measurement unit which measures a current flowing through the single cells or the battery pack;
• a temperature measurement unit which measures a temperature of the single cells or the battery pack, and
• a storage unit which stores internal resistance characteristic information indicative of correspondence relation between the temperature, state of charge, and internal resistance value of the single cells;
• wherein
• the control unit acquires the state of charge of the single cells by using the result of the measurement by the voltage measurement unit and by the current measurement unit;
• wherein
• the control unit acquires the internal resistance value corresponding to the temperature and the state of charge of the single cells from the internal resistance characteristic information;
• wherein
• the control unit uses an upper or lower voltage, an open circuit voltage, and the internal resistance value of each of the single cells to calculate the charging current or discharging current of the single cells, the control unit further determining the smallest of the charging currents or of the discharging currents to be a definitive permissible current;
• wherein
• either the sum of the voltage developed by each of the single cells when the single sells are supplied with the definitive permissible current, or the result of multiplying the number of serially connected single cells by an average obtained of the voltage developed by the single cells when the single sells are supplied with the definitive permissible current, the control unit further determining the sum or the result of the multiplication to be the voltage developed by the battery pack when the battery pack is supplied with the definitive permissible current, and wherein
• the control unit obtains permissible power by multiplying the definitive permissible current by the voltage developed by the battery pack when the battery pack is supplied with the definitive permissible current.