Patent ID: 7800342

Claim:
A battery pack management apparatus for managing a battery pack including a series connection of battery cells, said battery pack management apparatus being provided with a management unit for each of unit batteries each of which includes a single battery cell or a plurality of adjacent battery cells included in said battery pack, said battery pack management apparatus comprising: a selection circuit selecting one of said unit batteries; and a voltage detection circuit detecting a voltage across said selected unit battery; wherein said management unit provided for said selected unit battery is configured to perform a management process other than detection of said voltage across said selected unit battery on said selected unit battery; said management unit includes a conversion circuit converting said current on a connection line into a voltage, and a latch circuit latching said voltage converted by said conversion circuit, an output of said latch circuit being used as a command signal commanding said management unit to perform said management process; said management process is a process for discharging said selected unit battery; said battery cells are rechargeable batteries, and wherein said management unit includes a discharge path through which said selected unit battery is discharged, a discharge switch making a closed loop between said selected unit battery and said discharge path when being turned on, and a drive circuit turning on said discharge switch to thereby discharge said selected unit battery in response to said command signal; and said battery pack management apparatus includes a control circuit outputting a clock signal, and said management unit includes a comparator circuit comparing said voltage across said selected unit battery with one of two different threshold values selected in accordance with a logic value of said clock signal, and outputting a comparison result signal indicative of whether or not said selected unit battery is in an overcharged state or an overdischarged state to said control unit, and an inhibition circuit inhibiting said discharge switch from being turned on while said management unit is supplied with said clock signal from said control circuit.