Methods and apparatus for protecting battery cells from overcharge
First Claim
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1. A method of protecting at least one rechargeable battery cell from overcharge, comprising the steps of:
- monitoring a potential across the at least one rechargeable battery cell, and if the potential exceeds a predetermined value for at least a predetermined period, decoupling the at least one rechargeable battery cell from one of a plurality of output nodes, one output node coupled to a first polarity terminal of the rechargeable battery cell and another output node coupled to a second polarity terminal of the rechargeable battery cell; and
monitoring the potential across the at least one rechargeable battery cell, and if the potential continues to exceed the predetermined value, further decoupling the at least one rechargeable battery cell from one of the plurality of output nodes.
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Abstract
A method and apparatus for protecting at least one battery cell from overcharge utilizes a combination of at least one MOSFET switch and a separate fail-safe element such as a fuse or circuit breaker. The potential across the at least one battery cell is monitored to determine to determine whether a failure of the at the least one MOSFET switch has occurred, and in response to the determination of such a failure, a separate element such as a fuse is forced to open circuit to further disconnect the at least one battery cell from a charging current.
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Citations
53 Claims
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1. A method of protecting at least one rechargeable battery cell from overcharge, comprising the steps of:
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monitoring a potential across the at least one rechargeable battery cell, and if the potential exceeds a predetermined value for at least a predetermined period, decoupling the at least one rechargeable battery cell from one of a plurality of output nodes, one output node coupled to a first polarity terminal of the rechargeable battery cell and another output node coupled to a second polarity terminal of the rechargeable battery cell; and monitoring the potential across the at least one rechargeable battery cell, and if the potential continues to exceed the predetermined value, further decoupling the at least one rechargeable battery cell from one of the plurality of output nodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23)
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22. A method of protecting at least one rechargeable battery cell from overcharge, comprising the steps of:
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monitoring a potential across the at least one rechargeable battery cell, and if the potential exceeds a predetermined value for at least a first predetermined period, decoupling the at least one rechargeable battery cell from one of a plurality of output nodes, one output node coupled to a first polarity terminal of the rechargeable battery cell and another output node coupled to a second polarity terminal of the rechargeable battery cell; and monitoring the potential across the at least one rechargeable battery cell, and if the potential continues to exceed the predetermined value for at least a second predetermined period, further decoupling the at least one rechargeable battery cell from one of the plurality of output nodes.
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24. An apparatus for protecting at least one rechargeable battery cell from overcharge, comprising:
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a comparator for monitoring a potential across the at least one rechargeable battery cell; a logic circuit responsive to an output of the comparator for biasing into non-conduction at least one switching element coupled between the at least one rechargeable battery cell and one of a plurality of output nodes if the potential across the at least one rechargeable battery cell exceeds a predetermined value for a predetermined period; and a decoupling circuit driven by the logic circuit for decoupling the at least one rechargeable battery cell from at least one of the output nodes if the potential across the at least one rechargeable battery cell continues to exceed the predetermined value. - View Dependent Claims (25, 26, 28, 29, 32, 33, 36, 37, 40, 41, 44, 45, 48, 49, 52)
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27. An apparatus for protecting at least one rechargeable battery cell from overcharge, comprising:
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an integrator for integrating a difference between a potential across the at least one rechargeable battery cell and a first predetermined value; a logic circuit responsive to an output of the integrator for biasing into non-conduction at least one switching element coupled between the at least one rechargeable battery cell and one of a plurality of output nodes if the integrated difference exceeds a second predetermined value for at least a first predetermined period; and a decoupling circuit driven by the logic circuit for decoupling the at least one rechargeable battery cell from at least one of the output nodes if the integrated difference continues to exceed the second predetermined value. - View Dependent Claims (30, 31, 34, 35, 38, 39, 42, 43, 46, 47, 50, 53)
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51. The apparatus of claim 51, wherein the second decoupling circuit comprises:
a fusible element.
Specification