Battery controller and method for controlling a battery

• US 7,282,814 B2
• Filed: 03/08/2004
• Issued: 10/16/2007
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: Electrovaya Incorporated
• Original Assignee: Electrovaya Incorporated
• Inventors: Jacobs, James K.
• Primary Examiner(s): Sherry; Michael
• Assistant Examiner(s): AMAYA, CARLOS DAVID
• Application Number:
  US10/793,951
• Publication Number:
  US 20050194937A1
• Time in Patent Office: 1,317 Days
• Field of Search: 307/82
• US Class Current: 307/82
• 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 batteries;

a plurality of direct current to direct current (DC to DC) converters, each DC to DC converter comprising load-side terminals and battery-side terminals, with the load-side terminals of the DC to DC converters being connected to each other in series, and, each battery of the plurality of batteries is electrically connected to the battery-side terminals of a respective DC to DC converter; and

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;

wherein the series connected load-side terminals of 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;

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, the first battery electrically connected to the battery-side terminals of 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.

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 than or approximately equal to 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 series connected load-side terminals of the plurality of DC to DC converters.

8. The apparatus for charging and discharging a plurality of batteries as defined in claim 1 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 battery-side terminals of the second converter, to be charged with electrical energy being discharged from the first battery.