Temperature compensated voltage limited fast charge of nickel cadmium and nickel metal hybride battery packs
First Claim
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1. A method for charging a battery in a technology where cell voltage remains substantially constant under current-limited conditions during charging from one-quarter capacity to one-half capacity, comprising the steps of:
- (a.) applying charging current to said battery under current-limited conditions, while allowing the battery voltage to stay at a first substantially fixed value which is determined by the chemistry of the battery, and not by external circuits;
(b.) when the battery voltage begins to rise above said first fixed value, then clamping the voltage applied to said battery to a second fixed temperature-dependent value which is less than 120% of said first fixed value.
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Abstract
A method for charging nickel metal hydride and comparable batteries, in which the applied voltage is clamped to a temperature-dependent and current-dependent value which is greater than the constant voltage during most of the charging cycle, but less than any voltage at which gassing can occur.
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Citations
18 Claims
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1. A method for charging a battery in a technology where cell voltage remains substantially constant under current-limited conditions during charging from one-quarter capacity to one-half capacity, comprising the steps of:
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(a.) applying charging current to said battery under current-limited conditions, while allowing the battery voltage to stay at a first substantially fixed value which is determined by the chemistry of the battery, and not by external circuits; (b.) when the battery voltage begins to rise above said first fixed value, then clamping the voltage applied to said battery to a second fixed temperature-dependent value which is less than 120% of said first fixed value. - View Dependent Claims (2, 3, 4, 5)
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6. A method for charging a nickel metal hydride or analogous battery, comprising the steps of:
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(a.) applying charging current to said battery, while (b.) clamping the voltage applied to said battery to a temperature-dependent and current-dependent fixed value per cell, which is less than any voltage at which gassing can occur. - View Dependent Claims (7, 8)
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9. A computer system, comprising:
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a user input device; a microprocessor operatively connected to detect inputs from said input device; memory which is connected to be read/write accessible by said microprocessor; a video controller connected to said microprocessor; a display operatively connected to display data generated by said video controller at a first refresh rate; a power supply connected to provide power to said microprocessor, said memory, and said display; an AC adaptor which has a connection to receive an AC power input from an external source, and which generates DC power from said AC power input; and a nickel metal hydride or analogous battery which is charged by applying charging current to said battery, while clamping the voltage applied to said battery to a temperature-dependent and current-dependent fixed value per cell, which is less than any voltage at which gassing can occur. - View Dependent Claims (10, 11)
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12. A battery which is connected to a charger which charges said battery, during at least a portion of a respective charging period, by
applying charging current to said battery under current-limited conditions, while allowing the battery voltage to stay at a first substantially fixed value which is determined by the chemistry of the battery, and not by external circuits, and when the battery voltage begins to rise above said first fixed value, clamping the voltage applied to ; - aid battery to a second fixed temperature-dependent value which is less than 120% of said first fixed value.
- View Dependent Claims (13)
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14. A portable electronic system, comprising:
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electronic operating circuits which perform one or more functions; an AC adaptor which has a connection to receive an AC power input from an external source, and which generates DC power from said AC power input; and a battery pack; charging circuitry connected to charge said battery pack, during at least a portion of a respective charging period, by applying charging current to said battery under current-limited conditions, while allowing the battery voltage to stay at a first substantially fixed value which is determined by the chemistry of the battery, and not by external circuits, and when the battery voltage begins to rise above said first fixed value, clamping the voltage applied to said battery to a second fixed temperature-dependent value which is less than 120% of said first fixed value. - View Dependent Claims (15, 16, 17, 18)
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Specification