Battery charging apparatus and method
First Claim
1. A battery charger for a DC battery to be supplied by a primary AC power source, comprising:
- a stop-down transformer;
means for rectifying and regulating the output from the step-down transformer to produce a charging current of substantially constant magnitude;
means for generating a rapid succession of brief discharge current pulses;
means for directly superimposing said discharge current over said charging current;
means for controlling said discharge current in parallel with the battery, including a load resistor to fix the discharge current amplitude responsive to said generating means; and
means for substantially continuously isolating the AC power source during application of the discharge current pulse;
whereby accumulated hydrogen bubbles are actively scrubbed from the plates within the battery.
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Accused Products
Abstract
A battery charger and associated method for charging a DC battery utilizes a step-down transformer with high leakage reactance, and means for rectifying and regulating the step-down transformer output to continuously supply a constant charging current to the battery. Feedback from a current sensing means in series with the battery is provided for determining proper regulation. A discharge current controller in parallel with the battery contains a load resistor and switching means electrically responsive to a pulse train generator. The discharge current is applied to the battery in a rapid succession of brief pulses throughout the entire charging cycle, with the discharge current pulses being superimposed over the charging current. The discharge current pulse duration is selected utilizing the pulse train generator, between 50 and 100 microseconds with a time period on the order of twenty times the pulse duration. The amplitude of the discharge pulses, fixed by selection of the load resistor, is approximately three times the magnitude of the average nominal charging current. The rapid application of high amplitude current for an extremely brief pulse duration induces electromagnetic forces within the battery. A turbulence is produced which advantageously scrubs the battery plates to remove hydrogen bubbles, so the entire plate surface is available for the redeposition of ions.
58 Citations
23 Claims
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1. A battery charger for a DC battery to be supplied by a primary AC power source, comprising:
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a stop-down transformer; means for rectifying and regulating the output from the step-down transformer to produce a charging current of substantially constant magnitude; means for generating a rapid succession of brief discharge current pulses; means for directly superimposing said discharge current over said charging current; means for controlling said discharge current in parallel with the battery, including a load resistor to fix the discharge current amplitude responsive to said generating means; and means for substantially continuously isolating the AC power source during application of the discharge current pulse; whereby accumulated hydrogen bubbles are actively scrubbed from the plates within the battery. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of charging a DC battery, comprises the steps of:
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stepping-down a voltage from an AC power source; rectifying the stepped-down AC voltage; regulating a rectified current to continuously supply charging current of constant magnitude to the battery; superimposing over the charging current a discharge current pulse; repeating the application of the discharge current pulse at a constant interval; and isolating the AC power source during application of the discharge current pulse utilizing a relatively high leakage reactance characteristic of a transformer performing said stepping-down step. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A battery charger for a DC battery to be supplied by a primary AC power source, comprising:
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means for generating a rapid succession of brief discharge current pulses; means for controlling a discharge current in parallel with the battery, including a load resistor to fix the discharge current amplitude responsive to said generating means; a step-down transformer having an leakage reactance sufficiently high to block the flow of power from the AC power source through the means for controlling discharge current during a discharge current pulse; and means for rectifying and regulating the output from the step-down transformer to produce a charging current of substantially constant magnitude; whereby accumulated hydrogen bubbles are actively scrubbed from the plates within the battery. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A battery charger for a DC battery to be supplied by a primary AC power source, comprising:
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a step-down transformer; means for rectifying and regulating the output from the step-down transformer to produce a charging current of substantially constant magnitude; means for generating a rapid succession of brief discharge current pulses; means for controlling said discharge current in parallel with the battery, including a load resistor to fix the discharge current amplitude responsive to said generating means; said means for rectifying and regulating including a full wave bridge rectifier with a diode and an SCR; means for sensing the magnitude of the charging current applied to the battery; means for determining the proper time to send a triggering signal to the SCR to maintain a constant charging current as monitored by said current sensing means; a feedback line from an output of said current sensing means to an input of said determining means to provide a feedback signal; a signal line for connecting the output of said determining means to the SCR for application of the triggering signal; and said current sensing means comprising a current shunt in series with the battery; whereby accumulated hydrogen bubbles are actively scrubbed from the plates within the battery.
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23. A battery charger for a DC battery to be supplied by a primary AC power source, comprising:
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a step-down transformer; means for rectifying and regulating the output from the step-down transformer to produce a charging current of substantially constant magnitude; means for generating a rapid succession of brief discharge current pulses; and means for controlling said discharge current in parallel with the battery, including a load resistor to fix the discharge current amplitude responsive to said generating means; said means for generating the discharge current including a pulse train generator to supply a drive pulse; means for switching in series with the load resistor, responsive to the drive pulses to apply the discharge current pulses to the battery; and said switching means including a discharge transistor; whereby accumulated hydrogen bubbles are actively scrubbed from the plates within the battery.
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Specification