Patent ID: 7053588

Claim:
A power supply controller used for controlling the status of connection between a battery pack formed by combining a plurality of single cells or unit cells that are secondary batteries, and a load attached to the battery pack, the power supply controller comprising: contact switching devices provided between the battery pack and the load; a voltage measurement part for measuring voltage block-by-block on a time series basis, with each block containing a predetermined number of single cells or unit cells from the battery pack; a current measuring circuit for measuring electric current flowing in the battery pack with the same timing as the timing used by the voltage measurement part to measure the voltage of each block; an electric power computation part for receiving a voltage for each block from the voltage measurement part and an electric current from the current measuring circuit and calculating an electric power for each block; a counter for counting the number of times the electric power of each block calculated by the electric power computation part exceeds a permissible electric power value; and a control circuit controlling the contact switching devices to an open state at the point when a count value of the counter is equal to or higher than a preset value.