Patent ID: 7948210

Claim:
A battery pack connectable to at least one of an electric tool having a first tool terminal and a second tool terminal and a battery charger having a first charger terminal and a second charger terminal comprising: a first battery terminal selectively connectable to one of the first tool terminal and the first charger terminal; a second battery terminal connectable to corresponding one of the second tool terminal and the second charger terminal; a plurality of lithium battery cells connected between the first battery terminal and the second battery terminal, each lithium battery cell having a positive terminal and a negative terminal; an analog thermo sensing member that detects, in an analog form, a battery temperature of at least one of the plurality of lithium battery cells, and outputs an output preventing signal if the battery temperature is over a first predetermined temperature; and an analog switch element connected between the first battery terminal and the second battery terminal and in series with the plurality of lithium battery cells, and switched, based on the output preventing signal, to a state in which a current is prevented from flowing in the plurality of lithium battery cells.