Patent ID: 8649140

Claim:
A battery pack, comprising: a power cell; a higher supply rail and a lower power supply rail electrically interconnecting the power cell and a load; a first electronic switching device positioned, between the load and the power cell, on the lower power supply rail, wherein current passing through the lower power supply rail passes through the first electronic switching device's source and drain when the first electronic switching device is in a conducting condition; a current activated fuse having a current rated fuse below the power cell's current and operatively coupled to (a) the power cell through an extension from one of the power supply rails, and (b) a fuse current limiter's proximal end; the fuse current limiter's distal end operatively connects to the first electronic switching device's gate, the fuse current limiter limits the amount of the power cell's current that enters the current activated fuse and allows sufficient current from the power cell to pass to the first electronic switching device's gate in a conducting condition; an activation monitoring system that (a) monitors the battery pack for any over current condition, over voltage condition, thermally unacceptable condition, unacceptable battery or circuitry condition, or combinations thereof, and (b) transmits a closing current to a gate of an activation switch when the activation monitoring system detects the battery pack has an over current condition, an over voltage condition, a thermally unacceptable condition, an unacceptable battery or circuitry condition, or combinations thereof; the activation switch operatively connects to (a) the current activated fuse or the fuse circuitry positioned between the current activated fuse and the fuse current limiter, and (b) the power cell's most negative node or the lower power supply rail between the first electronic switching device and the power cell; the activation switch closes upon receipt of the closing current and activates a fuse opening current circuit wherein the power cell transmits current through the current activated fuse so the current activated fuse opens; in response to the current activated fuse opening, the first electronic switching device opens.