Patent ID: 7723960

Claim:
A Lithium battery pack, comprising: a plurality of Lithium battery cells connected in series; a first protection circuit outputting a first signal when the voltage of at least one of the plurality of Lithium battery cells goes below a first over-discharge voltage; a second protection circuit outputting a second signal when the voltage of other one of the plurality of Lithium battery cells goes below a second over-discharge voltage which is higher than the first over-discharge voltage; and a switch connected to the current path of the plurality of Lithium battery cells, the switch turning off and the current path being cut off when the first signal or the second signal is transmitted to the switch, wherein the second signal is not transmitted to the switch when the voltage of the other one of the plurality of Lithium battery cells goes below the second over- discharge voltage within a predetermined time so that a large load current can flow through the current path for a while.