RAPID BATTERY CHARGING SYSTEM AND METHOD

• US 3,852,652 A
• Filed: 08/06/1973
• Issued: 12/03/1974
• Est. Priority Date: 08/06/1973
• Status: Expired due to Term

• Current Assignee: Leon Jasinski
• Original Assignee: Leon Jasinski
• Inventors: Jasinski, Leon
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/385,937
• Time in Patent Office: 484 Days
• Field of Search: 320/30,31,35,36,39,40
• US Class Current: 320/150
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

A thermistor is internally mounted in a sealed nickel cadmium battery to be charged so as to sense the internal temperature of the battery and is electrically connected in a bridge to provide an electrical indication of the temperature of the battery. The electrical signal from the bridge is differentiated once to provide a signal representative of the rate of change of the temperature. A fast charging current is applied to the battery when the differentiated signal is below a predetermined amplitude and the temperature of the battery is within a predetermined range.

Claims

1. A system for rapidly charging a battery comprising:

a. temperature sensing means coupled to the battery for sensing changes of temperature within the battery;

b. conversion means connected to said temperature sensing means for converting the temperature sensed by said sensing means to an electrical signal;

c. a differentiating circuit connected to said conversion means for receiving the electrical signal therefrom and differentiating it once to provide a signal representative of the rate of change of the temperature;

d. power supply means; and

e. charge control means connected to said differentiating circuit and including first and second charging circuits connecting said power supply means to the battery for charging the battery at a first rate when the signal from the differentiating circuit is below a predetermined amplitude and at a second rate when the signal is above the predetermined amplitude.

2. A system as claimed in claim 1 wherein the temperature sensing means includes a thErmistor located in the battery.

3. A system as claimed in claim 2 wherein the conversion means includes a bridge circuit with the thermistor connected in one leg thereof.

4. A system as claimed in claim 1 wherein the charge control means includes temperature control means connected to receive the electrical signal from the conversion means and provide a signal to activate the first charging circuit when the electrical signal lies within a predetermined range and a signal to activate the second charging circuit when the electrical signal exceeds the predetermined range.

5. A system as claimed in claim 4 wherein the second charging circuit includes a resistive element connected in series with the battery and the power supply means and the first charging circuit includes a silicon controlled rectifier having an anode and a cathode connected in parallel with said resistive element and a gate.

6. A system as claimed in claim 5 including in addition an OR type circuit having a plurality of inputs connecting the charge control means to the gate of the silicon controlled rectifier.

7. A system as claimed in claim 6 wherein the temperature control means includes first and second circuits connected between the conversion means and two inputs of the OR type circuit, a signal on any of the plurality of inputs to the OR type circuit activating the silicon controlled rectifier, said first circuit providing a signal when the electrical signal from the conversion means is below the lower value of the predetermined range, and said second circuit providing a signal when the electrical signal from the conversion means exceeds the upper value of the predetermined range.

8. A system as claimed in claim 7 wherein the second circuit includes a circuit having hysteresis therein.

9. A system as claimed in claim 7 wherein a third input of the OR type circuit is connected to receive the signal from the differentiating circuit.

10. A system as claimed in claim 1 including in addition indicating means connected to the charge control means for indicating when the first charging circuit and the second charging circuit are operating.

11. A system as claimed in claim 1 wherein the battery is a sealed nickel cadmium battery.

12. A system for rapidly charging a battery from a power supply and wherein the battery has an internally mounted thermistor for indicating the internal temperature of the battery, comprising;

a. an electrical conversion circuit having terminals for connection to the thermistor of the battery, said circuit providing a first electrical signal representative of the temperature of the battery by converting the thermistor resistance variation into an electrical signal;

b. an electrical monitoring circuit connected to said conversion circuit for receiving the first electrical signal therefrom and converting such signal to a second electrical signal representing the rate of change of the temperature of the battery; and

c. charge control means connected to said monitoring circuit and including means for connecting the power supply means to the battery for charging the battery at a first rate when the second electrical signal from said monitoring circuit is below a predetermined level, and for charging the battery at a reduced rate when the said second electrical signal is above a predetermined level.

13. A method of rapidly charging a battery comprising the steps of:

a. sensing the internal temperature of the battery and producing therefrom an electrical signal representative of the sensed temperature;

b. differentiating the said electrical signal once and thereby creating a new electrical signal representing the rate of change of the previous signal; and

c. applying a charging current of a first level to the battery as long as the new electrical signal remains below a predetermined value and reducing the charging current when the new electrical signal exceeds the predetermined value.

14. A method of rapidly chargIng a battery comprising the steps of:

a. sensing the internal temperature of the battery and producing therefrom an electrical signal representative of the sensed temperature;

b. monitoring the said electrical signal and converting this signal into a new electrical signal representative of the rate of change of the previous signal; and

c. applying a charging current of a first level to the battery as long as the new electrical signal remains below a predetermined value and reducing the charging current when the new electrical signal exceeds the predetermined value.