Rapid battery charging method and apparatus
First Claim
1. A method for charging a NiMH or NiCd battery having a capacity C, the method comprising:
- applying a series of charging pulses to the battery, the charging pulses each having a duration in the range of 6 seconds to 30 seconds;
during each charging pulse passing a charging current having a magnitude in the range of 0.5×
C to 3.0×
C through the battery;
not charging the battery during an interval having a duration in the range of 5% of the duration of the previous charging pulse to 20% of the duration of the previous charging pulse.
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Accused Products
Abstract
Methods and apparatus for battery charging provide a charging cycle in which charging periods are separated by intervals. The intervals may include discharging periods. Typical charging sequences for nickel-metal hydride and nickel-cadmium batteries include charging periods having durations of 9 to 11 seconds during which a battery is charged at a rate between 1.9×C and 2.1×C and intervals which include discharging periods having durations of 0.9 to 1.1 seconds during which the battery is discharged at a rate between 0.19×C and 0.2l×C. The charge-rest-discharge-rest pattern is repeated until a specified battery voltage is reached or another event triggers the end of the charging cycle. Charging methods for lead acid batteries are disclosed in which charging pulses alternate with intervals during which the battery is not being charged. The charging current is stepwise reduced over a number of periods.
42 Citations
42 Claims
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1. A method for charging a NiMH or NiCd battery having a capacity C, the method comprising:
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applying a series of charging pulses to the battery, the charging pulses each having a duration in the range of 6 seconds to 30 seconds;
during each charging pulse passing a charging current having a magnitude in the range of 0.5×
C to 3.0×
C through the battery;
not charging the battery during an interval having a duration in the range of 5% of the duration of the previous charging pulse to 20% of the duration of the previous charging pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A battery charger for charging a NiCd or NiMH battery having a capacity of C Ampere-hours, the battery charger comprising:
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a) a power supply; and
,b) a control circuit configured to;
cause the power supply to apply a series of charging pulses to the battery, the charging pulses each having a duration in the range of 6 seconds to 30 seconds and delivering a charging current having a magnitude in the range of 0.5×
C to 3.0×
C; and
, not pass charging current through the battery during an interval having a duration in the range of 5% of the duration of the previous charging pulse to 20% of the duration of the previous charging pulse. - View Dependent Claims (28, 29, 30, 31, 32)
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33. A method for charging a lead-acid battery, the method comprising:
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a) setting a charging current magnitude to an initial value in the range of 0.65×
C to 0.70×
C;
b) for a charging time having a duration in the range of 60 seconds to 180 seconds, passing a charging current at the charging current magnitude through the battery;
c) for a discharge time having a duration in the range of 10 seconds to 20 seconds allowing the battery to discharge at a rate in the range of 0.05×
C to 0.07×
C;
d) repeating steps (b) and (c) in alternating sequence for a period having a duration in the range of 15 minutes to 26 minutes;
e) at the end of the period decreasing the charging current magnitude by approximately 0.05×
C;
f) repeating steps (b) through (d) until the charging current magnitude is less than or equal to 0.5×
C;
g) setting the charging current magnitude to approximately 0.5×
C;
h) for a charging time having a duration in the range of 60 seconds to 180 seconds, passing a charging current at the charging current magnitude through the battery;
i) for a discharge time having a duration in the range of 10 seconds to 20 seconds allowing the battery to discharge at a current having a magnitude in the range of 0.05×
C to 0.07×
C;
j) repeating steps (h) and (i) in alternating sequence until the battery voltage reaches a threshold value;
k) setting a charging voltage to a specified value;
l) for a charging period having a duration in the range of 60 seconds to 180 seconds, applying the charging voltage to the battery;
m) for a discharging period having a duration in the range of 10 seconds to 20 seconds allowing the battery to at a current having a magnitude in the range of 0.05×
C to 0.07×
C; and
,n) repeating steps (l) and (m) in alternating sequence until the battery is substantially fully charged. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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41. A method for charging a lead-acid battery, having a capacity C the method comprising:
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a) during each of a plurality of periods each having a duration in the range of 15 minutes to 25 minutes alternating between passing a charging current through the battery, the charging current being stepwise reduced in each successive period and providing an interval during which the battery is not being charged;
b) when the charging current has been stepwise reduced to a threshold value, maintaining the charging current at the threshold value and continuing to alternate between passing the charging current through the battery and providing the intervals until a voltage of the battery reaches a threshold voltage;
c) upon the battery voltage reaching the threshold voltage, maintaining a charging voltage at a constant value and continuing to between passing the charging current through the battery and providing the intervals; and
,d) terminating charging when the charging current produced by the charging voltage is less than a threshold current. - View Dependent Claims (42)
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Specification