Patent ID: 7710070

Claim:
A battery pack apparatus comprising: a casing; a battery within the casing; a circuit board within the casing and connected to the battery; a thermal fuse within the casing and connected between the battery and an outside of the casing; a detecting circuit on the circuit board operatively connected and configured to detect a drop in the voltage of the battery; a nonvolatile memory on said circuit board; and a data processor on said circuit board in communication with said nonvolatile memory, wherein, data on the battery voltage drop detected by the detecting circuit are stored in said nonvolatile memory, said data processor is placed in a power-off condition after said data on the battery voltage drop are stored in said nonvolatile memory, said data processor is configured to read said data upon being placed in a power-on condition, and said circuit board includes a configuration to blow said thermal fuse under the control of said data processor if a prior power-off condition was not caused by a voltage drop in said battery.