US 5,179,335 A · Battery charger

Abstract

A charger for charging rechargeable batteries including circuitry for supplying electrical charging power to said rechargeable battery so as to rapidly charge said rechargeable battery, interrupting circuitry for repeatedly interrupting said electrical charging power to said rechargeable battery for a preselected timed interval so as to permit the detection of the internal resistance free voltage of said battery during said interruption of said power, electrical comparing circuitry for comparing the internal resistance free voltage of said battery with a preselected reference voltage, and electrical control circuitry for reducing said power to said battery when said internal resistance free voltage exceeds said preselected reference voltage so as to reduce gradually the rate of charging of said rechargeable battery and maintain said internal resistance free voltage of said battery at said preselected reference voltage.

Claims47

Dependent claims

A charger for charging rechargeable batteries including:

(a) means for supplying an electrical charging power at an initial constant predetermined current level to a rechargeable battery initially at a rate in amperes greater than the capacity in ampere-hours of the battery (i.e., greater than 1 C), so as to rapidly charge said rechargeable battery;
(b) means for detecting the internal resistance free voltage of said rechargeable battery;
(c) means independent of the battery being charged for providing a preselected reference voltage;
(d) means for repeatedly interrupting said electrical charging power to said rechargeable battery for a preselected time interval so as to permit the instantaneous detection of the internal resistance free voltage of said battery at a point in time during said interruption of said electrical charging power;
(e) comparator means for comparing said internal resistance free voltage of said battery with said preselected reference voltage at said point in time and for producing an output logical error signal which is indicative of the value of said internal resistance free voltage compared to said reference voltage;
(f) logical memory means wherein said output logical error signal from the output of the said comparator means is entered during each preselected time interval;
and
(g) means for gradually reducing said electrical charging power when said internal resistance free voltage of said battery exceeds said preselected reference voltage as indicated by said output logical error signal, whereby the rate of charging of said rechargeable battery at said point in time is reduced so as to maintain said internal resistance free voltage at said preselected reference voltage.

5 more elements

A charger for charging rechargeable batteries including:

(a) means for generating a DC current at a preselected level so as to rapidly charge a rechargeable battery initially at a rate in amperes greater than the capacity in ampere-hours of the battery (i.e., greater than 1 C), during a first rapid charging interval;
(b) means for detecting the internal resistance free voltage of said rechargeable battery;
(c) circuitry means for repeatedly interrupting said current to said rechargeable batteries for a preselected time interval so as to permit the instantaneous detection of the internal resistance free voltage of said battery during said interruption of the said current at a point in time near the end of said preselected time interval;
(d) means independent of the battery being charged for electrically generating a preselected reference voltage;
(e) comparator means for comparing said internal resistance free voltage of said battery with said preselected reference voltage at said point in time and for producing an output logical error signal which is indicative of the value of said internal resistance free voltage compared to said reference voltage;
(f) logical memory means wherein said output logical error signal from the output of the said comparator means is entered during each preselected time interval;
and
(g) electrical control means activated by said comparator means for gradually reducing said current during a second reduced power charging interval when said internal resistance free voltage exceeds said preselected reference voltage as indicated by said output logical error signal, whereby the rate of charging of said rechargeable battery at said point in time is reduced so as to maintain said internal resistance voltage at said preselected reference voltage.

5 more elements

A charger for charging rechargeable batteries including:

(a) means for generating a DC current at a preselected level so as to rapidly charge a rechargeable battery initially at a rate in amperes greater than the capacity in ampere-hours of the battery (i.e., greater than 1 C), during a first rapid charging interval;
(b) means for detecting the internal resistance free voltage of said rechargeable battery;
(c) circuitry means for repeatedly interrupting said current to said rechargeable batteries for a preselected time interval so as to permit the instantaneous detection of the internal resistance free voltage of said battery during said interruption of the said current at a point in time near the end of said preselected time interval of from about 0.5 to about 10 milliseconds;
(d) means independent of the battery being charged for electrically generating a preselected reference voltage;
(e) comparator means for comparing said internal resistance free voltage of said battery with said preselected reference voltage at said point in time and for producing an output logical error signal which is indicative of the value of said internal resistance free voltage compared to said reference voltage;
(f) logical memory means wherein said output logical error signal from the output of the said comparator means is entered during each preselected time interval;
and
(g) electrical control means activated by said comparator means for gradually reducing said current during a second reduced power charging interval when said internal resistance free voltage exceeds said preselected reference voltage as indicated by said output logical error signal, whereby the rate of charging of said rechargeable battery at said point in time is reduced so as to maintain said internal resistance voltage at said preselected reference voltage.

5 more elements

A charger for charging rechargeable batteries including:

(a) means for generating a DC current at a preselected level so as to charge a rechargeable battery during a first charging interval;
(b) means for detecting the internal resistance free voltage of said rechargeable battery;
(c) circuitry means for repeatedly interrupting said current to said rechargeable batteries for a preselected time interval so as to permit the instantaneous detection of the internal resistance free voltage of said battery during said interruption of the said current at a point in time near the end of said preselected time interval of from about 0.5 to about 10 milliseconds;
(d) means independent of the battery being charged for electrically generating a preselected reference voltage;
(e) comparator means for comparing said internal resistance free voltage of said battery with said preselected reference voltage at said point in time and for producing an output logical error signal which is indicative of the value of said internal resistance free voltage compared to said reference voltage;
(f) logical memory means wherein said output logical error signal from the output of the said comparator means is entered during each preselected time interval;
and
(g) electrical control means activated by said comparator means for gradually reducing said current during a second reduced power charging interval when said internal resistance free voltage exceeds said preselected reference voltage as indicated by said output logical error signal, whereby the rate of charging of said rechargeable battery at said point in time is reduced so as to maintain said internal resistance voltage at said preselected reference voltage.

5 more elements

Dependencies are inferred from the claim text.

Battery charger

Life of this patent

Battery charger

Life of this patent

Abstract

Claims47