Abstract: The purpose of the present invention is to provide a lithium ion secondary battery having excellent performance in output discharging and regenerative charging when charging and A discharging handle heavy loads equivalent to at least 10 C in hour rate.

Abstract: The purpose of the present invention is to provide a cathode active material for a lithium secondary battery to give said battery a long-lasting high output property, and to disclose a method of manufacturing said active material and a lithium secondary battery using said active material, and to provide a setup module composed of a combination of plurality of said batteries.

Abstract: To provide a lithium secondary battery excellent in output characteristic at a large current by realizing an electrode which does not inhibit diffusion of lithium ions in particles, and has high electron conduction and high electrolytic solution holding ratio for realizing a low resistance positive electrode.

Abstract: A battery system includes a battery assembly having a plurality of modules, which are controlled by a system control circuit, each module including a module control circuit and a module by-pass circuit which is controlled via the module control circuit so as to suppress the charging variation among the plurality of modules. Each control circuit and the system-controlling circuit are connected to each other via a bilateral transmission medium and each module by-pass circuit is controlled based on information bilaterally transmitted between each module control circuit and the system control circuit via the bilateral transmission medium.

Abstract: During the charging of a secondary battery, the charging current is maintained, but the value of the current is changed for a short time, and the internal resistance of the battery is calculated from the voltage and the current before and after the changing of the charging current. The charging voltage is determined by adding an extra voltage equivalent to the voltage drop caused by the internal resistance to a designated voltage. Thus, it takes only a short time for stabilizing the voltage when the current is changed, because the charging current is not switched off completely. Therefore, the charging time can be shortened.