Battery pack overcharge protection system
First Claim
1. 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.
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Accused Products
Abstract
An overcharge protection device (OPD) is provided that may be used alone, or in combination with conventional charging protection systems, to protect a battery pack from the occurrence of a potentially damaging overcharging event. The OPD is designed to be coupled to, and interposed between, the terminals of the battery pack. During normal system operation, the OPD has no effect on the operation of the charging system or the battery pack. During an overcharging event, if overcharging is not prevented by another conventional system, the OPD of the invention creates a short across the terminals of the battery pack causing a battery pack fuse designed to provide battery pack short circuit protection to blow, thereby interrupting the current path from the charger to the battery pack and preventing the battery pack from being overcharged.
36 Citations
28 Claims
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1. 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:
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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. - View Dependent Claims (2, 5, 6, 7, 18)
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3. 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:
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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 first output terminal of said battery pack; 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. - View Dependent Claims (4, 19, 20, 21, 22)
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- 8. A system that provides overcharge protection for a battery pack during a battery pack charging cycle, 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, the system comprising a doped silicon junction device electrically connected between a first output terminal and a second output terminal of the battery pack, said battery pack comprised of a plurality of individual batteries, wherein a first lead of said doped silicon junction device is electrically connected to said first output terminal and a second lead of said doped silicon junction device is electrically connected to said second output terminal, wherein said doped silicon junction device is electrically coupled to said first output terminal at a location between said source of charging power and a first terminal contactor, wherein said first terminal contactor corresponds to said source of charging power, wherein said doped silicon junction device is configured to break down and conduct current at a predetermined threshold voltage and create a short between said first and second output terminals if a charging voltage corresponding to said charging power exceeds said predetermined threshold voltage, and wherein said doped silicon junction device has a sufficiently large I2t to cause a fuse corresponding to the battery pack to blow and interrupt a current path between said battery pack and said source of charging power.
- 10. A system that provides overcharge protection for a battery pack during a battery pack charging cycle, 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, the system comprising a doped silicon junction device electrically connected between a first output terminal and a second output terminal of the battery pack, said battery pack comprised of a plurality of individual batteries, wherein a first lead of said doped silicon junction device is electrically connected to said first output terminal and a second lead of said doped silicon junction device is electrically connected to said second output terminal, wherein said doped silicon junction device is electrically coupled to said first output terminal at a location between a first terminal contactor and said first output terminal, wherein said first terminal contactor corresponds to said source of charging power, wherein said doped silicon junction device is configured to break down and conduct current at a predetermined threshold voltage and create a short between said first and second output terminals if a charging voltage corresponding to said charging power exceeds said predetermined threshold voltage, and wherein said doped silicon junction device has a sufficiently large I2t to cause a fuse corresponding to the battery pack to blow and interrupt a current path between said battery pack and said source of charging power.
Specification