Patent ID: 8659270

Claim:
A method of protecting a battery pack from overcharging during a battery pack charging cycle, wherein said battery pack is comprised of a plurality of individual batteries, wherein during said battery pack charging cycle a source of charging power is coupled to the battery pack and provides charging power to the battery pack, said method comprising the steps of: electrically connecting a first lead of a doped silicon junction device to a first output terminal of said battery pack, wherein said doped silicon junction device is configured to break down and conduct current at a predetermined threshold voltage; locating an electrical contactor between a junction of said first lead of said doped silicon junction device and said first output terminal of said battery pack and said source of charging power; and electrically connecting a second lead of said doped silicon junction device to a second output terminal of said battery pack, wherein said second output terminal represents an oppositely charged terminal of said battery pack, and wherein when a voltage corresponding to said charging power during said battery pack charging cycle exceeds said predetermined threshold voltage said doped silicon junction device breaks down and creates a short between said first and second output terminals of said battery pack, wherein said short causes a fuse corresponding to said battery pack to blow and interrupt a current path between said battery pack and said source of charging power.