Patent ID: 7595610

Claim:
A battery pack comprising: a first external terminal; a second external terminal; a first battery cell electrically coupled with the first external terminal and the second external terminal; a first electrical switch electrically coupled in series with the first battery cell and the first external terminal; a first protection circuit electrically coupled to the first battery cell and electrically coupled to the first electrical switch, the first protection circuit having a first state when a first electrical condition of the first battery cell exists and having an absence of the first state when the first condition does not exist, the first electrical switch configured to be in an electrically open circuit state to prevent electrical current from flowing through the first electrical switch when the first state of the first protection circuit exists and to be in an electrically closed circuit state to allow electrical current to flow through the first electrical switch when the first state of the first protection circuit is absent; a second electrical switch electrically coupled in series with the first battery cell and the first external terminal, the second electrical switch electrically coupled in parallel with the first electrical switch; and a second protection circuit electrically coupled to the first battery cell and electrically coupled to the second electrical switch, the second protection circuit having a first state when the first electrical condition of the first battery cell exists and having an absence of the first state when the first condition does not exist, the second electrical switch configured to be in an electrically open circuit state to prevent electrical current from flowing through the second electrical switch when the first state of the second protection circuit exists and to be in an electrically closed circuit state to allow electrical current to flow through the second electrical switch when the first state of the second protection circuit is absent.