Apparatus and method for step-charging batteries to optimize charge acceptance
First Claim
1. Apparatus for charging a battery comprising:
- a controllable power source providing an electrical charging output at variable current or voltage levels;
means for connecting the power source to charging terminals of the battery;
control circuitry for controlling the power source to apply the electrical charging output to the battery at a target output level, and to periodically apply the electrical charging output to the battery at an increased output level above the target output level and at a decreased output level below the target output level;
a sensor for measuring a charging input to the battery and providing a target, an increased and a decreased charging input value corresponding to the charging input at each of the target, increased and decreased output levels, respectively; and
comparison circuitry responsive to the target, increased and decreased charging input values provided by the sensor for determining a first difference of the increased charging input value from the target charging input value, and a second difference of the decreased charging input value from the target charging input value, the comparison circuitry making a comparison of the first difference with the second difference and further being operatively connected to the control circuitry to adjust the target output level by increasing or decreasing the target output level in accordance with the comparison.
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Abstract
Apparatus and method for charging a battery, wherein a target voltage is applied to a battery. During charging, the applied voltage is periodically increased and decreased a predetermined amount to modify the applied voltage by a small step in either direction. The charging input is measured as the current flow to the battery at each of the applied levels, and the target charging voltage is adjusted in the direction of the improved charge acceptance as indicated by the differentials of the input current flow at the increased and decreased levels. By repeating the process, the charging voltage is continually moved in the direction of an optimized charge acceptance level. Alternatively, a target current is applied and increased and decreased by a small step and adjusted in the direction of the improved charge acceptance, which corresponds to the differentials of the resulting voltages at the increased and decreased levels.
254 Citations
21 Claims
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1. Apparatus for charging a battery comprising:
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a controllable power source providing an electrical charging output at variable current or voltage levels; means for connecting the power source to charging terminals of the battery; control circuitry for controlling the power source to apply the electrical charging output to the battery at a target output level, and to periodically apply the electrical charging output to the battery at an increased output level above the target output level and at a decreased output level below the target output level; a sensor for measuring a charging input to the battery and providing a target, an increased and a decreased charging input value corresponding to the charging input at each of the target, increased and decreased output levels, respectively; and comparison circuitry responsive to the target, increased and decreased charging input values provided by the sensor for determining a first difference of the increased charging input value from the target charging input value, and a second difference of the decreased charging input value from the target charging input value, the comparison circuitry making a comparison of the first difference with the second difference and further being operatively connected to the control circuitry to adjust the target output level by increasing or decreasing the target output level in accordance with the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of charging a battery comprising the steps of:
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controlling a power source to apply an electrical charging output to the battery at a target voltage or current output level, and to periodically apply the electrical charging output to the battery at an increased output level above the target output level and at a decreased output level below the target output level; measuring a charging input to the battery and providing a target, increased and decreased charging input value corresponding to the charging input at each of the target, increased and decreased output levels, respectively; determining a first difference of the increased charging input value from the target charging input value, and a second difference of the decreased charging input value from the target charging input value; comparing the first and second differences with one another to provide a comparison of the differences; and adjusting the target output level by increasing or decreasing the target output level in accordance with the comparison. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification