Battery charger with thermal runaway protection
First Claim
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1. A battery charging circuit comprising:
- a power input for accepting an AC energy source;
a power output connected to a battery to be charged and supplying the regulated voltage to the battery; and
a rectifier charging circuit for supplying current at the regulated voltage to the power output, and including a regulation control for controlling teh voltage;
a temperature sensing device located proximate to the battery;
scaling circuitry for converting a value of the temperature sensing device to a voltage magnitude;
a voltage output of the scaling circuitry connected to the regulation control;
wherein the improvement comprises;
voltage sensing leads connected to terminals of the battery being charged and to the rectifier charging circuit;
circuitry included in series with one of the voltage sensing leads for injecting a voltage into a path of the voltage sensing leads;
whereby the voltage injected into the path of the voltage sensing leads alters the charging voltage supplied by the rectifier charging circuit to the battery to compensate for a temperature sensed by the temperature sensing device.
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Abstract
A battery charger control includes a thermal sensor attached to the battery being charged. If the temperature readings indicate a thermal runaway condition the charging current output is adjusted in accord with the temperature reading by means of voltage injeciton into an output sense lead of the charging circuitry as a means of achieving a control that prevents thermal runaway of the battery while still permitting continuous charging of the battery.
209 Citations
4 Claims
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1. A battery charging circuit comprising:
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a power input for accepting an AC energy source; a power output connected to a battery to be charged and supplying the regulated voltage to the battery; and a rectifier charging circuit for supplying current at the regulated voltage to the power output, and including a regulation control for controlling teh voltage; a temperature sensing device located proximate to the battery; scaling circuitry for converting a value of the temperature sensing device to a voltage magnitude; a voltage output of the scaling circuitry connected to the regulation control; wherein the improvement comprises; voltage sensing leads connected to terminals of the battery being charged and to the rectifier charging circuit; circuitry included in series with one of the voltage sensing leads for injecting a voltage into a path of the voltage sensing leads; whereby the voltage injected into the path of the voltage sensing leads alters the charging voltage supplied by the rectifier charging circuit to the battery to compensate for a temperature sensed by the temperature sensing device. - View Dependent Claims (2, 3)
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4. A battery charging circuit as claimed in cliam 3;
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wherein the improvement further comprises; the thermistor being connected in series with a resistor to form a voltage divider, and the scaling circuitry includes an amplifier responsive to a divided voltage output of the voltage divider.
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Specification