Universal battery charging apparatus

• US 4,006,396 A
• Filed: 03/05/1975
• Issued: 02/01/1977
• Est. Priority Date: 01/18/1974
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bogut, Henry A.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/555,476
• Time in Patent Office: 699 Days
• Field of Search: 320/20-24, 320/39, 320/40, 320/35, 320/36, 320/32, 320/2, 320/37, 320/38
• US Class Current: 320/125
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

Battery charging apparatus for charging batteries having different optimum charging rates, and wherein there is included in the same housing with the battery an electrical element having a characteristic related to a predetermined charging rate of the battery. Terminals are provided on the housing for the battery and the electrical element, for connection to the charging apparatus, and the charging apparatus utilizes the value of the characteristic of the element to control the supply of charging current to the battery. The electrical element provided with the battery may be a resistor, and the charging apparatus connects the resistor in a circuit to develop a control potential which is utilized to control the charging current. This control potential operates through a regulator to control the current through a resistance which is connected to the base of a transistor which controls the charging current. The current through the resistance controls the potential developed thereacross to provide a control potential at the base of the transistor to thereby control the charging current. An improved timer including four IC comparators may be utilized to control the length of time charging current is applied to the battery. Also, if the battery includes a heat sensitive element, such as a thermistor, circuitry is provided for sensing the presence and value of the thermistor and supplying a suitable rapid charge current to the battery. A pair of light emitting diodes are connected to the charging circuit to indicate when charging current is supplied to the battery.

Claims

1. A battery charging system having a charging path for charging batteries having a variety of different capacities requiring different optimum charging rates, said system including in combination,

a charging rate sensing circuit, at least one battery cell having an optimum charging rate,

a fixed resistor related to a predetermined charging rate of said cell approximating the optimum charging rate thereof, and

battery terminals connected to said cell and to said fixed resistor to form a battery for connecting the battery into the battery charging system with only said cell in said charging path and said fixed resistor in said charging rate sensing circuit.

2. A battery charging system for charging batteries having a variety of different capacities requiring different optimum charging rates, said system including in combinaton,

a battery including at least one cell, an electrical element having a fixed characteristic related to a predetermined charging rate of said cell approximating the optimum charging rate, and battery terminals connected to said cell and to said electrical element,

connector means for making electrical connections to the terminals of said battery,

circuit means connected to said connector means for connection through said terminals of said battery to said electrical element thereof, said circuit means producing a control voltage having a value related to the characteristic of said electrical element,

charging current supply means connected to said connector means for connection to said cell through said terminals, said current supply means including control means for controlling the charging current supplied thereby in accordance with a control voltage applied thereto,

and means connecting said circuit means to said control means for applying the control voltage to said control means and controlling the charging current supplied to said cell to the predetermined charging rate of said cell.

3. Battery charging apparatus as claimed in claim 2 wherein the electrical element is a fixed resistor.

4. Battery charging apparatus in accordance with claim 3 wherein said circuit means includes resistance means and means coupled to the resistor associated with the battery for applying current through said resistance means having a value related to the value of the resistor, whereby a control voltage is developed across said resistance means having a value related to the value of the resistor.

5. Battery charging apparatus in accordance with claim 4 wherein said means for applying current to said resistance means includes an integrated circuit regulator having a control terminal, and including a circuit connecting said control terminal to said connector means for connection to the resistor provided as a component of the battery.

6. Battery charging apparatus in accordance with claim 5 wherein said means for applying current through said resistance means includes a transistor having base, emitter and collector electrodes, and reference means applying a reference voltage to said base electrode, with said collector electrode connected to said resistance means, and said emitter electrode connected to said connector means for connection to the resistor provided as a component of the battery.

7. Battery charging apparatus for charging batteries having a variety of different capacities requiring different optimum charging rates, and wherein each battery includes therewith an electrical element having a fixed characteristic related to a predetermined charging rate of the battery approximating the optimum charging rate, and terminals connected to the battery and to the electrical element, such apparatus including in combination;

connector means for making electrical connections to the terminals of a battery,

circuit means connected to said connector means for connection through the terminals of the battery to the electrical element thereof, said circuit means producing a control voltage having a value related to the characteristic of the electrical element,

charging current supply means connected to said connector means for connection to the battery through the terminals thereof, said current supply means including control means for controlling the charging current supplied thereby in accordance with a control voltage applied thereto, said charging current supply means including a transistor having an emitter-collector path for controlling the current supplied to said connector means for charging the battery, and a base electrode connected to said resistance means, whereby the voltage developed across said resistance means controls the conduction of said transistor,

and means connecting said circuit means to said control means for applying said control voltage to said control means and controlling the charging current supplied to the battery to the predetermined charging rate of the battery.

8. Battery charging apparatus in accordance with claim 7 including a diode connected in the circuit including said emitter-collector path of said transistor and said connector means for supplying charging current to the battery, switch means connected to said diode, and indicator means connected to said switch means, said switch means being rendered operative by the voltage across said diode when charging current is supplied therethrough to operate said indicator means.

9. Battery charging apparatus in accordance with claim 8 wherein said switch means is a transistor having a base-emitter junction connected across said diode, and said indicator means is a light emitting diode connected to the collector electrode of said transistor.

10. Battery charging apparatus for charging batteries having a variety of different capacities requiring different optimum charging rates, and wherein each battery includes therewith an electrical element having a fixed characteristic related to a predetermined charging rate of the battery approximating the optimum charging rate, and terminals connected to the battery and to the electrical element, such apparatus including in combination,

connector means for making electrical connections to the terminals of a battery,

circuit means connected to said connector means for connection through the terminals of the battery to the electrical element thereof, said circuit means producing a control voltage having a value related to the characteristic of the electrical element,

charging current supply means connected to said connector means for connection to the battery through the terminals thereof, said current supply means including control means for controlling the charging current supplied thereby in accordance with a control voltage applied thereto,

means connecting said circuit means to said control means for applying said control voltage to said control means and controlling the charging current supplied to the battery to the predetermined charging rate of the battery,

and automatic timing means connected to said circuit means and said control means for substantially reducing the charging current supplied to the battery a predetermined time after charging current is initially applied to the battery.

11. Battery charging apparatus as claimed in claim 10 wherein the automatic timing means includes a plurality of integrated circuit comparators and a coulometer, said comparators being connected in circuit with said coulometer for causing initial current to flow through said coulometer when charging current is applied to the battery, said coulometer charging resistance after a predetermined period of time and causing said comparators to reverse the direction of current through said coulometer and reduce the charging current supplied to the battery.

12. Battery charging apparatus as claimed in claim 11 wherein the automatic timing means includes circuitry providing a reverse current through said coulometer substantially greater than the initial current flowing therethrough for preparing the charging apparatus for the next charge in a time substantially shorter than the predetermined period.

13. Battery charging apparatus as claimed in claim 10 including in addition circuitry connected to said charging current supply means and said automatic timing means for reducing the current supplied to the battery to a trickle charging current at the predetermined time after charging current is initially applied to the battery.

14. Battery charging apparatus for charging batteries having a variety of different capacities requiring different optimum charging rates, and wherein each battery includes therewith an electrical element having a fixed characteristic related to a predetermined charging rate of the battery approximating the optimum charging rate, and terminals connected to the battery and to the electrical element, such apparatus including in combination,

connector means for making electrical connections to the terminals of a battery,

circuit means connected to said connector means for connection through the terminals of the battery to the electrical element thereof, said circuit means producing a control voltage having a value related to the characteristic of the electrical element,

charging current supply means connected to said connector means for connection to the battery through the terminals thereof, said current supply means including control means for controlling the charging current supplied thereby in accordance with a control voltage applied thereto,

means connecting said circuit means to said control means for applying said control voltage to said control means and controlling the charging current supplied to the battery to the predetermined charging rate of the battery,

and circuitry for supplying a rapid charging rate current to batteries including therewith a temperature sensitive electrical element connected to the terminals thereof and varying in resistance in accordance with changes of temperature of the battery, said circuitry comprising, a rapid rate detector connected to said connector means for connection through the terminals of the battery to the temperature sensitive electrical element thereof, and switch means connected to said rapid rate detector, said rapid rate detector sensing the presence of the temparature sensitive electrical element and the resistance value thereof and activating said switch when the resistance value is within a predetermined range, and said switch means being connected to the control means of said charging current supply means for controlling said supply means to supply to the battery a rapid charging rate current during activation of said switch means.

15. Battery charging apparatus as claimed in claim 14 including in addition delay means connected to said connector means for connection through the terminals to the battery, said delay means being further connected to said rapid rate detector for maintaining said detector inactive for a predetermined period of time after said connector means are attached to the terminals of a battery.

16. Battery charging apparatus as claimed in claim 15 wherein said delay means further includes overvoltage comparator circuitry for maintaining said detector inactive when the battery voltage is above a predetermined value.

17. Battery charging apparatus as claimed in claim 16 including in addition a charge complete detector connected to said switch and providing an output signal when said switch is deactivated by the resistance of said temperature sensitive electrical element exceeding the predetermined range, and locking means connected to said charge complete detector and said rapid rate detector for preventing said rapid rate detector from activating said switch after said locking means receives an output signal from said charge complete detector, and said locking means further being reset by the removal of the battery and the insertion of a new battery in the connector means.

18. Battery charging apparatus as claimed in claim 17 wherein the locking means includes a silicon controlled rectifier.

19. Battery charging apparatus as claimed in claim 17 wherein the rapid rate detector, the delay means, and the charge complete detector each include an integrated circuit comparator.

20. Battery charging apparatus as claimed in claim 18 including in addition an indicator having first and second light emitting diodes, said second light emitting diode being coupled in series with said silicon controlled rectifier and said first light emitting diode being coupled in parallel with said second light emitting diode and said silicon controlled rectifier, said first light emitting diode being further coupled to said charging current supply means for being activated with the application of a charging current to the battery, and the second light emitting diode being activated by conduction of said silicon controlled rectifier and the first light emitting diode being deactivated thereby.