BATTERY SYSTEM AND METHOD FOR CHARGING A LARGE NUMBER OF BATTERY CELLS WHICH ARE CONNECTED IN SERIES

摘要

PURPOSE: A battery system is provided to use low cost of electrical device and control the discharging balance among battery cells for preventing overvoltage. CONSTITUTION: A battery system(100) comprises several battery cells(10) which are connected in series connection and also connected in parallel connection. When applied voltage to an electrical device and the battery cells is over a threshold value(UBR), the resistance value of the electrical device is reduced and the several batter cells are connected to the electrical device in parallel connection. When the applied voltage to the battery cell which is connected to the battery cell in parallel connection is over the set voltage threshold value(UBR), the resistance value of the electrical device is reduced.