Battery device, internal combustion engine system including battery device, and motor vehicle equipped with internal combustion engine system

Abstract

A battery device of the invention has a high-voltage battery unit, which includes three battery modules Cthrough C, three voltage equalization circuits Bthrough B, and six switches SWthrough SW. Each of the three battery modules Cthrough Cincludes plural lithium secondary cells arranged in series. Each of the voltage equalization circuits Bthrough Bworks to equalize the voltages of the respective cells included in a corresponding one of the battery modules Cthrough C. The six switches SWthrough SWare individually switched on and off to switch over the connection state of the battery modules Cthrough Cbetween serial connection and parallel connection. In the battery device of the invention, the voltage equalization process activates the voltage equalization circuits Bthrough Bto respectively equalize the voltages of the plural cells included in each of the three battery modules Cthrough Cin the state of serial connection of the battery modules Cthrough C. After completion of the voltage equalization in each of the three battery modules Cthrough C, the voltage equalization process connects the three battery modules Cthrough Cin parallel and equalizes the voltages of the respective battery modules Cthrough C. This arrangement effectively reduces the power loss by the voltage equalization and thus enhances the total energy efficiency of the whole battery device.