Charging system and method for multicell storage batteries
First Claim
1. A battery charging system for use with a plurality of series connected cells, each of which having terminals of opposite polarity, wherein each cell requires protection from excessive voltage at and near the fully charged state, said system comprising:
- a first electrical means for charging said plurality of series connected cells at an initial charge rate;
control means for repetitively reducing said initial charge rate and for terminating the charging with said first electrical means; and
a second electrical means for charging each of said plurality of series connected cells with controlled and equal voltage.
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Abstract
A battery-charging system includes a first charging circuit connected in series with a plurality of battery cells for controlled current charging. A second charging circuit applies a controlled voltage across each individual cell for equalization of the cells to the fully charged condition. This controlled voltage is determined at a level above the fully charged open-circuit voltage but at a sufficiently low level to prevent corrosion of cell components by electrochemical reaction. In this second circuit for cell equalization, a transformer primary receives closely regulated, square-wave voltage which is coupled to a plurality of equal secondary coil windings. Each secondary winding is connected in parallel to each cell of a series-connected pair of cells through half-wave rectifiers and a shared, intermediate conductor.
85 Citations
16 Claims
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1. A battery charging system for use with a plurality of series connected cells, each of which having terminals of opposite polarity, wherein each cell requires protection from excessive voltage at and near the fully charged state, said system comprising:
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a first electrical means for charging said plurality of series connected cells at an initial charge rate; control means for repetitively reducing said initial charge rate and for terminating the charging with said first electrical means; and a second electrical means for charging each of said plurality of series connected cells with controlled and equal voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of charging a plurality of series-connected electrochemical cells wherein each cell requires protection from excess voltage at and near its full charge, said method comprising:
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passing an initial controlled current through said plurality of series-connected cells; repetitively reducing said controlled current until a predetermined current level through said plurality of cells is reached and then discontinuing said controlled current; imposing charge from a source of controlled and equal, open-circuit voltage across each of said plurality of series-connected cells until a nearly equal state of charge is established in each cell. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification