METHOD AND APPARATUS FOR CHARGING BATTERIES
First Claim
1. A battery charger for charging a battery having an opening to the atmosphere comprising a charging current source for delivering current to said battery to be charged, means for periodically discharging said battery while it is being charged from said charging current source, transducer means for measuring the rate of gas evolution within said battery, and means for controlling a continuous increase in the duration of the operation of said battery discharging means during successive operations thereof as the measured rate of gas evolution tends to increase, wherein the rate at which said battery discharging means is operated is constant and said transducer means causes the duration of the operation of said battery discharging means to increase during successive operations thereof as said battery is progressively charged.
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Accused Products
Abstract
A method and apparatus for rapidly charging a battery. During the charging process, the battery is caused to accept and store the desired charging current by producing discharge pulses whose rate and/or durations vary in accordance with the relative magnitudes of the charging current and the acceptance current level of the battery.
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Citations
20 Claims
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1. A battery charger for charging a battery having an opening to the atmosphere comprising a charging current source for delivering current to said battery to be charged, means for periodically discharging said battery while it is being charged from said charging current source, transducer means for measuring the rate of gas evolution within said battery, and means for controlling a continuous increase in the duration of the operation of said battery discharging means during successive operations thereof as the measured rate of gas evolution tends to increase, wherein the rate at which said battery discharging means is operated is constant and said transducer means causes the duration of the operation of said battery discharging means to increase during successive operations thereof as said battery is progressively charged.
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2. A battery charger in accordance with claim 1 wherein said battery discharging means includes means for limiting the magnitude of the discharge current from said battery to a maximum value substantially greater than the magnitude of the current delivered to said battery from said charging current source.
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3. A battery charger for charging a battery having an opening to the atmosphere comprising a charging current source for delivering current to said battery to be charged, means for periodically discharging said battery while it is being charged from said charging current source, transducer means for measuring the rate of gas evolution within said battery, integrating means controlled by said transducer means for measuring the average integral of the rate of gas evolution within said battery over a substantial number of periods of operation of said discharging means, and feedback means responsive to said integrating means for controlling changes in the rate of the discharge of said battery by said discharging means to maintain the average integrated value of gas evolution substantially constant independent of the voltage of said battery during a substantial portion of the time required to charge said battery.
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4. A battery charger in accordance with claim 3 wherein said discharging means remains inoperative after the start of the charging of said battery until the measured rate of gas evolution exceeds a predetermined minimum value.
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5. A battery charger in accordance with claim 4 wherein the current delivered to said battery by said charging current source is approximately constant.
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6. A battery charger in accordance with claim 5 wherein said feedback means continuously controls an increase in the rate of operation of said battery discharging means.
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7. A battery charger in accordance with claim 6 wherein the magnitude of the charging current delivered by said charging current source is independent of the voltage of said battery.
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8. A battery charger in accordance with claim 3 wherein said transducer means is a variable impedance element whose impedance varies with the pressure within said battery, and said integrating means includes a capacitor coupled to said transducer means, and means for charging said capacitor through said transducer means, and said feedback means includes means responsive to the potential across said capacitor reaching a predetermined magnitude for controlling the operation of said battery discharging means.
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9. A battery charger in accordance with claim 8 wherein the duration of the operation of said battery discharging means is constant for each operation thereof and said feedback means causes the rate of the operation of said battery discharging means to increase as said battery is progressively charged.
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10. A battery charger in accordance with claim 3 wherein said battery discharging means includes means for limiting the magnitude of the discharge current from said battery to a maximum value substantially greater than the magnitude of the current delivered to said battery from said charging current source.
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11. A battery charger in accordance with claim 3 wherein the current delivered to said battery by said charging current source is approximately constant.
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12. A battery charger in accordance with claim 3 wherein said feedback means continuously controls an increase in the rate of operation of said battery discharging means.
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13. A method for charging a battery having an opening to the atmosphere comprising the steps of:
- a. delivering a charging current to said battery, b. periodically discharging the battery while it is being charged by said charging current, c. measuring the rate of gas evolution within the battery, d. measuring the average integral of the rate of gas evolution within the battery over a substantial number of periods during which the battery is discharged, and e. controlling changes in the rate of the discharge of the battery to maintain the average integrated value of gas evolution substantially constant independent of the voltage of the battery during a substantial portion of the time required to charge the battery.
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14. A method for charging a battery in accordance with claim 13 wherein the battery is not discharged in step (b) after the start of the charging of the battery until the measured rate of gas evolution exceeds a predetermined minimum value.
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15. A method for charging a battery in accordance with claim 13 wherein the charging current delivered in step (a) is approximately constant.
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16. A method for charging a battery in accordance with claim 13 wherein the magnitude of the charging current delivered to the battery in step (a) is made independent of the voltage of the battery.
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17. A method for charging a battery in accordance with claim 3 wherein the duration of each discharge of the battery in step (b) is constant for each discharge thereof and the rate at which the battery is discharged in successive cycles increases as the battery is progressively charged.
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18. A method for charging a battery in accordance with claim 13 wherein the discharge current from the battery in step (b) is limited to a maximum value substantially greater than the charging current delivered to the battery in step (a).
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19. A method for charging a battery in accordance with claim 13 wherein said battery is discharged in step (b) even before it is first charged in step (a).
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20. An energy conversion system comprising a battery having an opening to the atmosphere, said battery including transducer means for measuring the rate of gas evolution in the battery as charging current is delivered thereto, a charging current source for delivering current to said battery, means for periodically discharging said battery while it is being charged from said charging current source, integrating means controlled by said transducer means for measuring the average integral of the rate of gas evolution in the battery over a substantial number of periods of operation of said discharging means, and feedback means responsive to said integrating means for controlling changes in the rate of the discharge of said battery by said discharging means to maintain the average integrated value of gas evolution substantially constant independent of the voltage of the battery during a substantial portion of the time required to charge said battery.
Specification