Circulating current battery heater

• US 5,990,661 A
• Filed: 04/30/1998
• Issued: 11/23/1999
• Est. Priority Date: 04/30/1998
• Status: Expired due to Term

• Current Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG), FCA US LLC (Stellantis NV), University of Toledo
• Original Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG), University of Toledo
• Inventors: Stuart, Thomas A., Ashtiani, Cyrus N.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/070,331
• Time in Patent Office: 572 Days
• Field of Search: 320/103, 320/118, 320/128, 320/135, 320/153, 320/DIG. 14, 320/DIG. 33
• US Class Current: 320/128
• CPC Class Codes: H01M 10/615 Heating or keeping warm
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/633 characterised by algorithms, flow charts, software details or the like
• CPC Class Codes: H01M 10/637 characterised by the use of reversible temperature-sensitive devices, e.g. NTC, PTC or bimetal devices; characterised by control of the internal current flowing through the cells, e.g. by switching means for preventing undesired use or discharge H01M50/572
• CPC Class Codes: H05B 1/0236 for vehicles
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A circuit for heating energy storage devices such as batteries is provided. The circuit includes a pair of switches connected in a half-bridge configuration. Unidirectional current conduction devices are connected in parallel with each switch. A series resonant element for storing energy is connected from the energy storage device to the pair of switches. An energy storage device for intermediate storage of energy is connected in a loop with the series resonant element and one of the switches. The energy storage device which is being heated is connected in a loop with the series resonant element and the other switch. Energy from the heated energy storage device is transferred to the switched network and then recirculated back to the battery. The flow of energy through the battery causes internal power dissipation due to electrical to chemical conversion inefficiencies. The dissipated power causes the internal temperature of the battery to increase. Higher internal temperatures expand the cold temperature operating range and energy capacity utilization of the battery. As disclosed, either fixed frequency or variable frequency modulation schemes may be used to control the network.

Claims

1. A circuit for heating a first energy storage device, the circuit comprising:

first switching means operative in open and closed circuit states;

a first element for providing a unidirectional current path connected in parallel with the first switching means;

second switching means operative in open and closed circuit states, the second switching means connected in series with the first switching means;

a switch junction formed at the connection of the first switching means and the second switching means;

a second element for providing a unidirectional current path connected in parallel with the second switching means;

a series resonant element, operable for storing energy, connected to the switch junction;

second energy storage means connected in a first loop with the first switching means and the series resonant element; and

said first energy storage device connected in a second loop with the second switching means and the series resonant element.

2. The circuit of claim 1 wherein the series resonant element is an inductor.

3. The circuit of claim 1 wherein the series resonant element is an inductor and a capacitor in series.

4. The circuit of claim 1 including modulation means for controlling the first switching means and the second switching means.

5. A circuit for heating a plurality of batteries, the circuit comprising:

first switching means operative in open and closed circuit states;

a first diode connected in parallel with the first switching means;

second switching means operative in open and closed circuit states, the second switching means connected in series with the first switching means;

a switch junction formed at the connection of the first switching means and the second switching means;

a second diode connected in parallel with the second switching means;

a series resonant element, operable for storing energy, connected to said switch junction;

at least a first battery connected in a first loop with the first switching means and the series resonant element;

a second battery connected in a second loop with the second switching means and the series resonant element;

modulation means operatively associated with the first switching means and the second switching means, the modulation means selected from the group of;

pulse-width modulation means and frequency modulation means; and

a sensor operatively associated with the modulation means for controlling the operation thereof.

6. The circuit of claim 5 wherein the series resonant element is an inductor.

7. The circuit of claim 5 wherein the series resonant element is an inductor and a capacitor in series.

8. The circuit of claim 5 wherein the sensor is selected from the group of:

Hall effect current sensors, resistive shunt current sensors, battery temperature sensors, and battery voltage sensors.

9. A circuit for heating a battery having a plurality of cells, the circuit comprising;

a first transistor operative in open and closed circuit states;

a first diode connected in parallel with the first transistor;

a second transistor operative in open and closed circuit states, the second transistor connected in series with the first transistor;

a switch junction formed at the connection of the first transistor and the second transistor;

a second diode connected in parallel with the second transistor;

a series resonant element, operable for storing energy, connected to said switch junction;

a first cell connected in a first loop with the first transistor and the series resonant element; and

a second cell connected in a second loop with the second transistor and the series resonant element.

10. The circuit of claim 9 wherein the series resonant element is an inductor.

11. The circuit of claim 9 wherein the series resonant element is an inductor and a capacitor in series.

12. The circuit of claim 9 including modulation means for controlling the first transistor and the second transistor.

13. The circuit of claim 12 wherein the modulation means is pulse-width modulation.

14. The circuit of claim 12 wherein the modulation means is frequency modulation.

15. The circuit of claim 12 including at least one sensor operatively associated with the modulation means for controlling the operation thereof.

16. A circuit for heating a plurality of batteries, the circuit comprising;

a first IGBT operative in open and closed circuit states;

a first diode connected in parallel with the first IGBT;

a second IGBT operative in open and closed circuit states, the second IGBT connected in series with the first IGBT;

a switch junction formed at the connection of the first IGBT and the second IGBT;

a second diode connected in parallel with the second IGBT;

an inductor, operable for storing energy, connected to said switch junction;

a first battery connected in a first loop with the first IGBT and the inductor; and

a second battery connected in a second loop with the second IGBT and the inductor.

17. A method of heating a plurality of batteries, said method comprising:

connecting a first energy storage element across at least a first battery;

conducting energy from said first battery through the first energy storage element, thereby heating said first battery by dissipating power within said first battery;

redirecting the energy from the first storage element into a second storage element;

recycling the energy from the second storage element into the first storage element; and

redirecting the energy from the first storage element into said first battery, thereby heating said first battery by dissipating power within said first battery.

18. The method of claim 17 which includes:

sensing the temperature of said first battery; and

adjusting the ratio of time during which current is conducted through said first battery dependent on the temperature of said first battery.

19. The method of claim 17 wherein the second storage element is a second battery.