Electronic DC battery charger

• US 4,061,956 A
• Filed: 08/23/1976
• Issued: 12/06/1977
• Est. Priority Date: 11/06/1975
• Status: Expired due to Term

• Current Assignee: Utah Research & Development Company Incorporated
• Original Assignee: Utah Research & Development Company Incorporated
• Inventors: Boyd, William A., Brown, Lowell K., Newman, William Albert
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/716,524
• Time in Patent Office: 470 Days
• Field of Search: 320/22, 320/23, 320/24, 320/35, 320/36, 320/39, 320/21, 320/43
• US Class Current: 320/153
• CPC Class Codes: B60L 2200/10 Air crafts
• CPC Class Codes: B60L 2200/32 Waterborne vessels
• CPC Class Codes: B60L 2200/36 Vehicles designed to transport cargo, e.g. trucks
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/525 Temperature of converter or components thereof
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y10S 320/12 : Precharging analysis, e.g. determining presence of battery
• CPC Class Codes: Y10S 320/13 : Fault detection
• CPC Class Codes: Y10S 320/24 : Inductor

Abstract

A battery charger receives direct current power from an external source through a power connector. Switch means receives the power from the power connector and supplies it to a boost circuit which is removably and conductively connected to a battery. A control circuit is connected to receive a battery voltage signal from the battery and a battery temperature signal from a temperature sensor positioned to detect battery temperature. The control circuit determines the state of charge of the battery from the voltage and temperature signals. The control circuit supplies (1) switching signals to the switch means to cause the switch to be conductive, and (2) boosting signals to the boost circuit to cause the boost circuit to charge the battery in accordance with a preselected charging program related to the state of charge of the battery. A safety circuit may also be adapted to sense unsafe battery and battery charger parameters and cause the control circuit to generate a switching signal to cause the switch means to be nonconductive upon the occurrence thereof. The battery charger is particularly adaptable for use with vehicles.

Claims

1. A battery charger comprising:

power connector means for removable conductive connection to an external source of direct current power;

switch means conductively connected to said power connector means to receive power therefrom;

a boost circuit conductively connected to said switch means to receive power therefrom and removably conductively connected to a battery to be charged to supply power thereto;

temperature sensing means positioned to sense the temperature of said battery and generate a temperature reflective signal;

a control circuit (1) conductively connected to said battery to receive a battery voltage signal therefrom, (2) conductively connected to said switch means to supply a switching signal thereto, (3) conductively connected to said boost circuit to supply a boosting signal thereto, and (4) conductively connected to said temperature sensing means to receive said temperature reflective signal, said control circuit (1) receiving said battery voltage signal and said temperature reflective signal to determine the temperature adjusted stage of charge of said battery, (2) supplying said switching signal to cause said switch means to supply power to said boost circuit in accordance with a preselected charging program related to said battery'"'"'s state of charge, and (3) supplying said boosting signal to said boost circuit to cause said boost circuit to supply charging current signals to said battery which vary in magnitude and form in accordance with said preselected charging program related to said state of charge of said battery.

2. The battery charger of claim 1 wherein said control circuit includes:

voltage control means which receives said battery voltage signal and said temperature reflective signal and generates an output signal reflecting the temperature adjusted state of charge of said battery;

a boost control circuit conductively connected (1) to receive the output of said voltage control means, (2) to supply said boosting signal, and (3) to receive a topping signal;

a topping control circuit conductively connected (1) to receive the output of said voltage control means and (2) to supply a topping signal to said boost control circuit;

a switch control circuit conductively connected (1) to receive a topping signal from said topping control circuit, (2) to receive the output signal of said voltage control means, and (3) to supply said switching signal; and

wherein

said preselected charging program is comprised of a plurality of charging modes automatically selected by said control circuit which are related to the state of charge of said battery.

3. The battery charger of claim 2 wherein said preselected charging program is comprised of:

a first mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of effective total discharge wherein said switch control and said boost control generate boosting signal and switching signals respectively which cause said switch means and boost circuits to pass a trickle charge current to said battery;

a second mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of substantial discharge wherein said switch control generates a switching signal to cause said switch to be conductive and pass full main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a large charging current to said battery which diminishes at a preselected rate until said temperature adjusted state of charge of said battery reflects a low stage of charge of said battery;

a third mode in which said temperature adjusted state of charge of said battery reflects a low state of charge of said battery, said switch control generates a switching signal which causes said switch to be conductive and pass main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery comprised of intervaled pulses of direct current until said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge of said battery;

a fourth mode in which said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge said switch control generates a switching signal to cause said switch to be conductive and pass main power to said boost circuit and said topping control generates a topping signal to cause said boost control to generate a boosting signal which in turn causes said boost circuit to supply a charging signal comprised of intervaled pulses of direct current having an average trickle charge value for a preselected period of time.

4. The battery charger of claim 3 wherein said charging program includes a fifth mode in which said temperature adjusted state of charge of said battery reflects a preselected state of charge less than nearly fully charged and more than a low state of charge wherein said control circuit operates to repetitively charge in said third mode and then in said fourth mode for a preselected period of time.

5. The battery charger of claim 4 wherein said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery in said third mode which is comprised of intervaled pulses of direct current which increase in frequency to maintain a constant average charging current as the battery state of charge increases.

6. The battery charger of claim 1 further comprising a safety circuit conductively connected to receive signals reflecting charger and battery parameters and to said control circuit to supply a safety signal wherein said safety circuit includes means to receive said signal reflecting charger and battery parameters and generate safety signals reflective of preselected unsafe parameters to cause said control circuit to send a switching signal to in turn cause the switch means to become nonconductive.

7. The battery charger of claim 6 wherein said safety circuit includes voltage sensor means conductively connected to said main power connector to sense input power voltage and to said switch control to cause said switch control to generate a switching signal which in turn causes said switch means to become nonconductive when said input power voltage is outside of a preselected range.

8. The charger of claim 7 wherein said safety circuit includes charger temperature detector means conductively connected to said switch control, said charger temperature detector means generating a high charger temperature signal when the temperature of the battery charger reaches a first preselected temperature and remains above a second preselected temperature which is below said first preselected temperature and supplying said signal to said switch control to cause said switch control to send a switching signal to said switch means to cause said switch means to become nonconductive.

9. The charger of claim 8 wherein said safety circuit includes a shorted sensor and hot battery detector circuit conductively connected to said temperature sensing means to receive signals therefrom and conductively connected to said switch control, said shorted sensor and hot battery detector circuit generating a safety signal when said temperature sensing means supplies a temperature reflective signal indicating that said battery has reached a preselected temperature and when said temperature sensing means supplies a signal reflecting that said temperature sensing means has become electrically shorted and supplying a safety signal to said switch control to cause said switch control to generate a switching signal to cause said switch means to become nonconductive.

10. The charger of claim 9 wherein said safety circuit includes a shorted cell detector conductively connected to said battery to receive a signal reflecting a shorted battery cell condition and conductively connected to said switch control, said shorted cell detector generating a safety signal when a signal reflecting a shorted battery cell condition is received and supplying said safety signal to said switch control to cause said switch control to send a switching signal to said switch means to cause said switch means to become nonconductive.

11. The charger of claim 10 wherein said safety circuit includes a fault indicator circuit conductively connected (1) to said voltage sensor to receive an over voltage signal reflecting input power over voltage, (2) to said charger temperature detector to receive said high charger temperature signal, (3) to said shorted sensor and hot battery detector to receive its output safety signal and (4) to said shorted cell detector to receive its output safety signal, said fault indicator circuit generating a fault signal, said fault indicator circuit generating a fault signal and supplying it to an external indicator to cause external indication thereof upon receipt of an input signal.

12. The battery charger of claim 11 wherein said control circuit includes:

voltage control means which receives said battery voltage signal and said temperature reflective signal and generates an output signal reflecting the temperature adjusted state of charge of said battery;

a boost control circuit conductively connected (1) to receive the output of said voltage control means, (2) to supply said boosting signal, and (3) to receive a topping signal;

a topping control circuit conductively connected (1) to receive the output of said voltage control means and (2) to supply a topping signal to said boost control circuit;

a switch control circuit conductively connected (1) to receive a topping signal from said topping control circuit, (2) to receive the output signal of said voltage control means, and (3) to supply said switching signal; and

wherein

said preselected charging program is comprised of a plurality of charging modes automatically selected by said control circuit which are related to the state of charge of said battery.

13. The battery charger of claim 12 wherein said preselected charging program includes:

a first mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of effective total discharge, said switch control and said boost control generate boosting signal and switching signals respectively which cause said switch means and boost circuits to pass a trickle charge current to said battery;

a second mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of substantial discharge, said switch control generates a switching signal to cause said switch to be conductive and pass tull main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a large charging current to said battery which diminishes at a preselected rate until said temperature adjusted state of charge of said battery reflects a low state of charge of said battery;

a third mode in which said temperature adjusted state of charge of said battery reflects a low state of charge of said battery, said switch control generates a switching signal which causes said switch to be conductive and pass main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery comprised of intervaled pulses of direct current until said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge of said battery;

a fourth mode in which said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge said switch control generates a switching signal to cause said switch to be conductive and pass main power to said boost circuit and said topping control generates a topping signal to cause said boost control to generate a boosting signal which in turn causes said boost circuit to supply a charging signal comprised of intervaled pulses of direct current having an average trickle charge value for a preselected period of time.

14. The battery charger of claim 13 wherein said charging program includes a fifth mode in which said temperature adjusted state of charge of said battery reflects a preselected state of charge less than nearly fully charged and more than a low state of charge, said control circuit operates to charge in said third mode and then in said fourth mode for a preselected period of time.

15. The battery charger of claim 14 wherein said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery in said third mode which is comprised of intervaled pulses of direct current which increase in frequency to maintain a constant average charging current as the battery state of charge increases.

16. The battery charger of claim 15 wherein said control circuit includes a relay control circuit conductively connected (1) to said safety circuit to receive an input power low voltage signal therefrom, (2) to said switch control to supply a relay signal thereto, (3) to external inputs to receive relay operate signals therefrom and (4) to external relays to supply operation signals thereto, said relay control generating and supplying signals to operate relays external to said battery charger and relay signals to cause said switch means to become nonconductive in accordance with preselected relay operating conditions.

17. The battery charger of claim 16 wherein said boost control circuit is conductively connected to an external signal generator to receive a manually initiated inhibit signal which terminates boost control circuit operation.

26. The combination of claim 8 wherein said preselected charging program includes:

a first mode in which said switch means and said boost circuit pass a constant trickle charge current to said battery when said battery is at and below a state of substantially total discharge;

a first mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of effective total discharge, said switch control and said boost control generate boosting signal and switching signals respectively which cause said switch means and boost circuits to pass a trickle charge current to said battery;

a second mode in which said temperature adjusted state of charge of said battery reflects a battery state of charge of substantial discharge, said switch control generates a switching signal to cause said switch to be conductive and pass tull main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a large charging current to said battery which diminishes at a preselected rate until said temperature adjusted state of charge of said battery reflects a low state of charge of said battery;

a third mode in which said temperature adjusted state of charge of said battery reflects a low state of charge of said battery, said switch control generates a switching signal which causes said switch to be conductive and pass main power to said boost circuit and said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery comprised of intervaled pulses of direct current until said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge of said battery;

a fourth mode in which said temperature adjusted state of charge of said battery reflects a nearly fully charged state of charge said switch control generates a switching signal to cause said switch to be conductive and pass main power to said boost circuit and said topping control generates a topping signal to cause said boost control to generate a boosting signal which in turn causes said boost circuit to supply a charging signal comprised of intervaled pulses of direct current having an average trickle charge value for a preselected period of time.

27. The combination of claim 26 wherein said charging program includes a fifth mode in which said temperature adjusted state of charge of said battery reflects a preselected state of charge less than nearly fully charged and more than a low state of charge, said control circuit operates to charge in said third mode and then in said fourth mode for a preselected period of time.

28. The combination of claim 27 wherein said boost control generates a boosting signal to cause said boost circuit to supply a charging signal to said battery in said third mode which is comprised of intervaled pulses of direct current which increase in frequency to maintain a constant average charging current as the battery state of charge increases.

29. The combination of claim 28 wherein said control circuit includes a relay control circuit conductively connected (1) to said safety circuit to receive an input power low voltage signal therefrom, (2) to said switch control to supply a relay signal thereto, (3) to external inputs to receive relay operate signals therefrom and (4) to external relays to supply operation signals thereto, said relay control generating and supplying signals to operate relays external to said battery charger and relay signals to cause said switch means to become nonconductive in accordance with preselected relay operating conditions.

30. The combination of claim 29 wherein said boost control circuit is conductively connected to an external signal generator to receive a manually initiated inhibit signal which terminates boost control circuit operation.

31. The combination of claim 30 wherein said external inputs of said relay control include a signal indicating failure of said external source and a signal indicating engine start, and wherein said fault circuit is comprised of means to illuminate an external lamp indicator visually observable by personnel operating said vehicle.

18. In combination with a vehicle of the type having a high energy battery associated therewith, a battery charger comprising:

power connector means for removable conductive connection to an external source of direct current power;

switch means conductively connected to said power connector means to receive power therefrom;

a boost circuit conductively connected to said switch means to receive power therefrom and removably conductively connected to a battery to be charged to supply power thereto;

temperature sensing means positioned to sense the temperature of said battery and generate a temperature reflective signal;

a control circuit (1) conductively connected to said battery to receive a battery voltage signal therefrom, (2) conductively connected to said switch means to supply a switching signal thereto, (3) conductively connected to said boost circuit to supply a boosting signal thereto, and (4) conductively connected to said temperature sensing means to receive said temperature reflective signal, said control circuit (1) receiving said battery voltage signal and said temperature reflective signal to determine the temperature adjusted state of charge of said battery, (2) supplying said switching signal to cause said switch means to supply power to said boost circuit in accordance with a preselected charging program related to said boosting signal to said boost circuit to cause said boost circuit to supply charging current signals to said battery which vary in magnitude and form in accordance with said preselected charging program related to said state of charge of said battery.

19. The combination of claim 18 further comprising a safety circuit conductively connected to receive signals reflecting charger and battery parameters and to said control circuit to supply a safety signal wherein said safety circuit includes means to receive said signal reflecting charger and battery parameters and generate safety signals reflective of preselected unsafe parameters to cause said control circuit to send a switching signal to in turn cause the switch means to become nonconductive.

20. The combination of claim 19 wherein said safety circuit includes voltage sensor means conductively connected to said main power connector to sense input power voltage and to said switch control to cause said switch control to generate a switching signal which in turn causes said switch means to become nonconductive when said input power voltage is outside of a preselected range.

21. The combination of claim 20 wherein said safety circuit includes charger temperature detector means conductively connected to said switch control, said charger temperature detector means generating a high charger temperature signal when the temperature of the battery charger reaches a first preselected temperature and remains above a second preselected temperature which is below said first preselected temperature and supplying said signal to said switch control to cause said switch control to send a switching signal to said switch means to cause said switch means to become nonconductive.

22. The combination of claim 21 wherein said safety circuit includes a shorted sensor and hot battery detector circuit conductively connected to said temperature sensing means to receive signals therefrom and conductively connected to said switch control, said shorted sensor and hot battery detector circuit generating a safety signal when said temperature sensing means supplies a temperature reflective signal indicating that said battery has reached a preselected temperature and when said temperature sensing means supplies a signal reflecting that said temperature sensing means has become electrically shorted and supplying a safety signal to said switch control to cause said switch control to generate a switching signal to cause said switch means to become nonconductive.

23. The combination of claim 22 wherein said safety circuit includes a shorted cell detector conductively connected to said battery to receive a signal reflecting a shorted battery cell condition and conductively connected to said switch control, said shorted cell detector generating a safety signal when a signal reflecting a shorted battery cell condition is received and supplying said safety signal to said switch control to cause said switch control to send a switching signal to said switch means to cause said switch means to become nonconductive.

24. The combination of claim 23 wherein said safety circuit includes a fault indicator circuit conductively connected (1) to said voltage sensor to receive an over voltage signal reflecting input power over voltage, (2) to said charger temperature detector to receive said high charger temperature signal, (3) to said shorted sensor and hot battery detector to receive its output safety signal and (4) to said shorted cell detector to receive its output safety signal, said fault indicator circuit generating a fault signal, said fault indicator circuit generating a fault signal and supplying it to an external indicator to cause external indication thereof upon receipt of an input signal.

25. The combination of claim 24 wherein said control circuit includes:

voltage control means which receives said battery voltage signal and said temperature reflective signal and generates an output signal reflecting the temperature adjusted state of charge of said battery;

a boost control circuit conductively connected (1) to receive the output of said voltage control means, (2) to supply said boosting signal, and (3) to receive a topping signal;

a topping control circuit conductively connected (1) to receive the output of said voltage control means and (2) to supply a topping signal to said boost control circuit;

a switch control circuit conductively connected (1) to receive a topping signal from said topping control circuit, (2) to receive the output signal of said voltage control means, and (3) to supply said switching signal; and

wherein

said preselected charging program is comprised of a plurality of charging modes automatically selected by said control circuit which are related to the state of charge of said battery.