Battery controller and method for controlling a battery

• US 20050194937A1
• Filed: 03/08/2004
• Published: 09/08/2005
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: Electrovaya Incorporated
• Original Assignee: Electrovaya Incorporated
• Inventors: Jacobs, James K.
• Granted Patent: US 7,282,814 B2
• Time in Patent Office: Days
• US Class Current: 320/135
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery controller for charging and discharging a plurality of batteries is disclosed. The battery controller has a plurality of direct current to direct current (DC to DC) converters connected to each other in series. Each battery of a plurality of batteries is electrically connectable to a respective DC to DC converter. A co-ordinator connected to each of the plurality of DC to DC converters controls charging and discharging of the battery electrically connected to the respective converter. The co-ordinator can also control charging and discharging of any one of the batteries to ensure that the battery retains sufficient electrical capacity, and, to increase the longevity of the respective batteries. Because each battery is electrically connected to a respective DC to DC converter, the energy from one battery can be used to charge another battery in order to monitor battery characteristics including energy capacity of each battery. Each of the DC to DC converters is selected to operate preferably below 30 volts while the total voltage of the entire battery system can be much more than 30 volts depending on the number of DC to DC converters placed in series.

Claims

1. An apparatus for charging and discharging a plurality of batteries, said apparatus comprising:

a plurality of direct current to direct current (DC to DC) converters, connected to each other in series, and, each battery of the plurality of batteries is electrically connectable to a respective DC to DC converter;

a co-ordinator connected to each of the plurality of DC to DC converters for controlling charging and discharging of the battery electrically connected to the respective converter; and

wherein the plurality of DC to DC converters are electrically connected to at least one load and the co-ordinator co-ordinates the transfer of electrical power from the plurality of batteries to the one or more loads.

2. The apparatus for charging and discharging a plurality of batteries as defined in claim 1 wherein each of the plurality of DC to DC converters operate in the range of 5 volts to 30 volts.

3. The apparatus for charging and discharging a plurality of batteries as defined in claim 2 wherein each of the plurality of DC to DC converters operate in the range of 10 volts to 25 volts.

4. The apparatus for charging and discharging a plurality of batteries as defined in claim 3 wherein each of the plurality of DC to DC converters operate in the range of 15 volts to 22 volts.

5. The apparatus for charging and discharging a plurality of batteries as defined in claim 2 wherein:

N represents the total number of DC to DC converters in the plurality of DC to DC converters;

V_total represents the expected total voltage of the nominal discharge of the apparatus;

the voltage of any one DC to DC converter is approximately V_total/N; and

V_total/N is less or approximately equal to than 30 volts.

6. The apparatus for charging and discharging a plurality of batteries as defined in claim 1 further comprising a current monitor for monitoring the current passing through the plurality of DC to DC converters connected in series.

7. The apparatus for charging and discharging a plurality of batteries as defined in claim 1 further comprising a voltage monitor for detecting the total voltage across the plurality of DC to DC converters connected in series.

8. The apparatus as defined in claim 7 wherein the voltage monitor is distributed amongst each of the DC to DC converters and the voltage across each of the DC to DC converters in the series is monitored and transmitted to the co-ordinator;

and

wherein the co-ordinator receives signals from each of the DC to DC converters indicating the voltage across each of the DC to DC converters and determines the total voltage across the series of DC to DC converters.

9. The apparatus for charging and discharging the plurality of batteries as defined in claim 1 wherein the co-ordinator sends a first control signal to a first converter of the plurality of DC to DC converters to cause the first converter to discharge a first battery of the plurality of batteries, said first battery electrically connected to the first converter;

and

wherein the co-ordinator monitors the discharging of the first battery to determine characteristics of the first battery including its electrical capacity.

10. The apparatus for charging and discharging a plurality of batteries as defined in claim 9 wherein the co-ordinator sends a second control signal to a second converter of the plurality of converters to cause a second battery of the plurality of batteries, said second battery being electrically connected to the second converter, to be charged with electrical energy being discharged from the first battery.

11. A method for charging and discharging a plurality of batteries, said method comprising:

electrically connecting one direct current to direct current (DC to DC converter) of a plurality of DC to DC converters to a respective battery of the plurality of batteries;

electrically connecting a co-ordinator to each of the plurality of DC to DC converters for controlling, charging and discharging of the respective batteries; and

wherein the plurality of DC to DC converters are electrically connected to each other in series and the co-ordinator co-ordinates transfer of electrical power from the respective batteries to one or more loads through the series of DC to DC converters.

12. An apparatus for providing electrical power, the apparatus comprising:

a plurality of fuel-less batteries structured to discharge and thereby supply electrical power;

a first battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the first battery power converter being connected across at least one fuel-less battery of the plurality of fuel-less batteries; and

a second battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the second battery power converter being connected across at least one fuel-less battery of the plurality of fuel-less batteries and with the load-side terminals of the first and second battery power converters being electrically connected to each other in series.

13. The apparatus of claim 12 wherein:

each of the plurality of batteries outputs direct current power;

the first battery power converter is a DC to DC converter; and

the second battery power converter is a DC to DC converter.

14. The apparatus of claim 12 wherein the battery-side terminals of the first battery power converter and the battery-side terminals of the second battery power converter are connected across non-identical sets of fuel-less batteries of the plurality of fuel-less batteries.

15. The apparatus of claim 14 wherein:

the battery-side terminals of the first battery power converter are connected across a first fuel-less battery of the plurality of batteries; and

the battery-side terminals of the second battery power converter are connected across a second fuel-less battery of the plurality of batteries.

16. The apparatus of claim 14 further comprising at least one additional battery power converter, wherein:

the at least one additional battery power controller each comprises battery-side terminals and load-side terminals; and

the battery-side terminals of each of the first battery power converter, the second battery power converter and each additional battery power controller being respectively connected across a unique battery from the plurality of fuel-less batteries.

17. The apparatus of claim 12 wherein the first and second battery power converters are voltage converters.

18. The apparatus of claim 12 wherein the first and second battery power converters are current converters.

19. The apparatus of claim 12 wherein the first battery power converter comprises bypass circuitry to allow the passage of electrical power through the first battery power converter even in the absence of power supplied at the battery-side terminals of the first battery power converter.

20. An apparatus for storing and discharging electrical power, the apparatus comprising:

a plurality of rechargeable batteries structured to store and discharge electrical power;

a first battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the first battery power converter being connected across at least one rechargeable battery of the plurality of rechargeable batteries; and

a second battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the second battery power converter being connected across at least one rechargeable battery of the plurality of rechargeable batteries and with the load-side terminals of the first and second battery power converters being electrically connected to each other in series.

21. The apparatus of claim 20 further comprising:

a coordinator component structured and located to allow selective charging and discharging of the rechargeable batteries by selectively controlling the operation of the first and second battery power converters.

22. The apparatus of claim 21 wherein the coordinator component controls the selective charging and discharging of the rechargeable batteries so that the first and second batteries discharge at substantially the same rate with respect to the respective capacities of the batteries.

23. The apparatus of claim 20 wherein the first and second battery power converters are structured as DC to DC converters with buck-boost operation.

24. The apparatus of claim 23 wherein the first and second battery power converters each comprise:

at least one inductor; and

at least one switch with the switch being structured at located to at least partially control the flow of current to the inductor, with the operation of the at least one switch being controlled by the coordinator component.

25. The apparatus of claim 24 wherein the first and second battery power converters each further comprise at least two switches, inclusive of the at least one switch, with the operation of the at least two switches being controlled by the coordinator component.

26. The apparatus of claim 24 wherein the first and second battery power converters each further comprise at least one capacitor connected across the inductor.

27. An apparatus for providing electrical power, the apparatus comprising:

a plurality of batteries structured to discharge and thereby supply electrical power, the plurality of batteries comprising at least a first battery subset and a second battery subset, wherein the first battery subset and the second battery subset are not identical subsets;

a first battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the first battery power converter being connected across the first battery subset;

a first battery power diagnostic device connected across the first battery subset;

a second battery power converter comprising battery-side terminals and load-side terminals, with the battery-side terminals of the second battery power converter being connected across the second battery subset; and

a second battery power diagnostic device connected across the second battery subset.

28. An apparatus for providing electrical power, the apparatus comprising:

a plurality of batteries structured to discharge and thereby supply electrical power;

a plurality of battery power converters electrically connected to the plurality of batteries so that the electrical discharge of the plurality of batteries supplies power to the battery power converters; and

control circuitry structured and located to control the battery power converters so that at least two of the plurality batteries will discharge during normal operation of the apparatus at proportionate rates with respect to the respective capacities of the batteries.

29. The apparatus of claim 28 wherein the discharge of the batteries is controlled by the control circuitry so that the batteries discharge at substantially the same rate during normal operation of the apparatus.