Alkaline battery charger and method of operating same
First Claim
Patent Images
1. A battery charger, comprising:
- means for charging each of one or more cells with a charge pattern which includes a time period of individual charge alternating with one or more time periods of individual discharge;
means for providing a charge cut-off voltage which represents a value sufficiently above a desired cell open circuit voltage to insure adequate charge acceptance, but sufficiently low to avoid significant cell degradation;
means for comparing the cell voltage of each of said one or more cells being charged to said cut-off voltage at the end of each time period of charge;
means for stopping said charge of said one or more cells individually whenever said voltage of said one or more individual cells being charged exceeds said cut-off voltage;
means for stopping said charge pattern of said one or more cells individually when said one or more individual cells being charged discharges above said cut-off voltage for a longer period of time as compared to the duration of the individual charge period;
means for stopping said charge pattern of said one or more cells individually when said cell voltage of said one or more individual cells being charged averages about said cut-off voltage for a longer period of time as compared to the duration of said time period of individual charge; and
means for restarting said charge pattern of said one or more cells after a long pulse time period.
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Abstract
Apparatus and methods for recharging various types of battery cells are enclosed involving alternating periods of charging and discharging of the cells, a reference charge cut-off voltage, a comparator for comparing cell voltage with cut-off voltage, and a circuit for stopping charging activity when cell open circuit voltage is at least a desired minimum voltage. Charge activity is terminated following the achievement of a minimum acceptable state-of-charge so as to limit the total current delivered to the cell in order to prevent cell degradation.
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Citations
12 Claims
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1. A battery charger, comprising:
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means for charging each of one or more cells with a charge pattern which includes a time period of individual charge alternating with one or more time periods of individual discharge; means for providing a charge cut-off voltage which represents a value sufficiently above a desired cell open circuit voltage to insure adequate charge acceptance, but sufficiently low to avoid significant cell degradation; means for comparing the cell voltage of each of said one or more cells being charged to said cut-off voltage at the end of each time period of charge; means for stopping said charge of said one or more cells individually whenever said voltage of said one or more individual cells being charged exceeds said cut-off voltage; means for stopping said charge pattern of said one or more cells individually when said one or more individual cells being charged discharges above said cut-off voltage for a longer period of time as compared to the duration of the individual charge period; means for stopping said charge pattern of said one or more cells individually when said cell voltage of said one or more individual cells being charged averages about said cut-off voltage for a longer period of time as compared to the duration of said time period of individual charge; and means for restarting said charge pattern of said one or more cells after a long pulse time period. - View Dependent Claims (2, 3, 4, 5, 6)
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7. The method of charging one or more cells, comprising the steps of:
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charging each of said one more cells with a charge pattern which includes a time period of individual charge alternating with one or more time periods of individual discharge; setting a charge cut-off voltage which represents a value sufficiently high to insure adequate charge acceptance, but sufficiently low to avoid significant cell degradation; comparing the voltage of each of said one or more cells being charged to said cut-off voltage at the end of each time period of charge; stopping said charge of said one or more cells individually whenever said voltage of said one or more cells individually being charged exceeds said cut-off voltage; means for stopping said charge pattern of said one or more cells individually when said cell voltage of said one or more individual cells being charged averages about said cut-off voltage for a longer period of time as compared to the duration of said time period of individual charge; and restarting said charge pattern of said one or more cells after a long pulse time period. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification