Energy storage device for loads having variabl power rates

• US 20080111508A1
• Filed: 01/18/2008
• Published: 05/15/2008
• Est. Priority Date: 04/05/2001
• Status: Active Grant

• Current Assignee: Electrovaya Incorporated
• Original Assignee: Electrovaya Incorporated
• Inventors: Bhola, Rakesh, Jacobs, James, Dasgupta, Sankar
• Granted Patent: US 7,570,012 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: B60L 53/00 Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: H01M 6/5033 used as charging means for another battery
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• 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 90/14 : Plug-in electric vehicles

Abstract

An electrical energy storage device for storing electrical energy and supplying the electrical energy to a driving motor at different power levels is disclosed. The electrical storage device has an energy battery connected to a power battery. The energy battery has a higher energy density than the power battery. However, the power battery can provide electrical power to the electrical motor at different power rates, thereby ensuring that the motor has sufficient power and current when needed. The power battery can be recharged by the energy storage battery. In this way, the power battery temporarily stores electrical energy received from the energy battery and both batteries can provide electrical energy at the different power rates as required by the motor. The energy storage device can be releasably connected to an external power source in order to recharge both batteries. Both batteries can be recharged independently to optimize the recharging and lifetime characteristics of the batteries.

Claims

1. A power source for supplying electrical power to a driving motor, said driving motor drawing electrical power at different rates, the power source comprising:

a first rechargeable energy battery having a first total impedance for storing electrical energy and providing electrical power to the electrical motor at a first range of power rates;

a second rechargeable power battery having a second total impedance, less than the first total impedance, for storing electrical energy and providing electrical power to the electrical motor at a second range of power rates;

wherein the energy battery is directly connected in parallel with the power battery and the driving motor such that the electrical energy stored in the energy battery is provided to the driving motor in combination with electrical energy stored in the power battery; and

wherein the energy battery substantially continuously recharges the power battery with any excess power not provided to the driving motor.

2. The power source as defined in claim 1 further comprising a battery controller capable of controlling the substantially continuous recharging of the power battery with electrical energy from the energy battery not required by the driving motor.

3. The power source as defined in claim 2 wherein the battery controller controls the substantially continuous recharging of the power battery by controlling the electrical energy passing through a first connection from the energy battery to the power battery.

4. The power source as defined in claim 2 wherein the battery controller utilizes inherent control of the energy battery and power battery, such that the battery controller initially connects the power battery and energy battery in parallel.

5. The power source as defined in claim 4 wherein the controller initially connects each of the power battery, energy battery and electrical motor in parallel.

6. The power source as defined in claim 1 wherein the power battery and energy battery have a range of overlapping nominal voltages.

7. The power source as defined in claim 6 wherein the energy battery substantially continuously recharges the power battery with any excess power not used by the driving motor.

8. The power source as defined in claim 7 wherein the power battery consists of at least one bank of 8 lead acid batteries in series, each lead acid battery having a nominal voltage of 10.5 volts to 13 volts and the energy battery consists of at least one bank of 27 lithium ion cells connected in series, each lithium ion cell having a nominal voltage of 3 volts to 4.2 volts.

9. The power source as defined in claim 1 wherein the second total impedance is between 10% to 60% of the first total impedance.

10. The power source as defined in claim 9 wherein the second total impedance is between 35% to 50% of the first total impedance.

11. The power source as defined in claim 4 further comprising a switch between the energy battery and the power battery;

and

wherein the controller initially connects the power battery to the energy battery in parallel by controlling the switch along the first connection.

12. The power source as defined in claim 1 wherein the energy battery is a lithium based battery selected from the group consisting of non-aqueous lithium-ion batteries, lithium air batteries and polymer lithium ion batteries, and, the power battery is a lead-acid battery.

13. The power source as defined in claim 1 wherein the energy battery is a non-aqueous polymer lithium battery pack.

14. The power source as defined in claim 13 wherein the power source has a casing and a portion of the casing is occupied by the non-aqueous polymer lithium battery pack.

15. The power source as defined in claim 5 wherein the driving motor drives a vehicle within which the power battery and energy battery are contained and, wherein the controller can be contained within or removed from the vehicle.

16. A method for storing electrical energy for an electrical load drawing electrical power at different rates, said method comprising:

charging a rechargeable energy battery having a first total impedance;

charging a rechargeable power battery having a second total impedance, less than the first total impedance;

supplying electrical energy from the energy battery and the power battery to the electrical load, said rechargeable power battery, said rechargeable energy battery and said electrical load are connected to each other in parallel such that electrical energy stored in the energy battery is provided to the electrical load in combination with energy stored in the power battery when required by the electrical load, and, when not required by the electrical load electrical energy from the energy battery substantially recharges the power battery;

substantially continuously recharging the power battery from the energy battery with electrical energy not required by the electrical load.

17. A method as defined in claim 16 further comprising:

connecting the energy battery in parallel with the power battery prior to connecting the energy battery to the load.

18. A method as defined in claim 16 wherein the electrical load is a driving motor in a vehicle to drive the vehicle, and, the rechargeable energy battery and the rechargeable power battery are contained in the vehicle with the power battery located nearer the driving motor than the energy battery.

19. A method as defined in claim 18 further comprising:

periodically recharging the energy battery, from an external fixed electrical source, when the energy capacity of the energy battery falls below a threshold.

20. A method as defined in claim 16 wherein the rechargeable energy battery is selected from the group consisting of non-aqueous lithium-ion batteries, lithium air batteries, polymer lithium-ion batteries and sodium-sulfur batteries;

and

wherein the rechargeable power battery is selected from the group consisting of lead-acid batteries, high-rate lithium batteries, lithium-ion batteries, high-rate nickel aqueous batteries, nickel metal batteries, nickel alloy hybrid bearing batteries and nickel cadmium batteries.