Electric energy storage device and method of charging and discharging the same

• US 7,660,084 B2
• Filed: 12/13/2003
• Issued: 02/09/2010
• Est. Priority Date: 12/30/2002
• Status: Active Grant

• Current Assignee: Maxwell Technologies Korea Co., Ltd. (UCAP Power, Inc.)
• Original Assignee: NESS CAP Company Limited
• Inventors: Lee, Ha-Young, Lee, Hee-Young, Kim, Heui-Soo, Kim, Eun-Sil, Jung, Yong-Ho, Kim, Sung-Min, Park, Sung-Chul
• Primary Examiner(s): Nguyen; Danny
• Application Number:
  US10/540,919
• Publication Number:
  US 20080013224A1
• Time in Patent Office: 2,250 Days
• Field of Search: 361/16, 361/23, 361/91.1, 320/116, 320/118, 320/120
• US Class Current: 361/16
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

Disclosed are an electric energy storage device having a good cycle characteristic and a temperature characteristic and a method of charging and discharging the electric energy storage device. The electric energy storage device including a capacitor and a secondary battery combined in series is provided. When the capacitor of the electric energy storage device is an electric double layer capacitor, the capacitor is used to the voltage of OV or less to increase an available energy usage.

Claims

1. An electric energy storage device comprising a capacitor and a secondary battery combined in series;

and

an over-voltage preventing device connected to both end portions of the capacitor,

wherein an electric capacity of the secondary battery is about four (4) to 100 times of an electric capacity of the capacitor, and

wherein the over-voltage preventing device is an over-voltage preventing circuit comprising a voltage comparator for comparing a predetermined voltage and an applied voltage, a switch for flowing electricity when the applied voltage exceeds the predetermined voltage and a breeder resistor for discharging the capacitor when the switch flows the electricity.

2. The electric energy storage device as claimed in claim 1, wherein the secondary battery is one of a lead acid battery, a nickel-cadmium (Ni—

Cd) battery, a nickel-metal hydride battery and a lithium ion battery, and the capacitor is one of an electric double layer capacitor, a metal oxide pseudo capacitor and a hybrid capacitor.

3. The electric energy storage device as claimed in claim 1, wherein the over-voltage preventing device is a Zener diode.

4. The electric energy storage device as claimed in claim 1, wherein the over-voltage preventing device is a shunt regulator.

5. The electric energy storage device as claimed in claim 1, further comprising an over-discharge preventing device connected to both end portions of the secondary battery.

6. A method of charging and discharging of an electric energy storage device comprising a capacitor and a secondary battery connected to the capacitor in series, and an over-voltage preventing device connected to both end portions of the capacitor, the method comprising:

charging the electric energy storage device to a sum of an operating voltage of the capacitor and a nominal voltage of the secondary battery; and

discharging the capacitor to 0V or less,

wherein an electric capacity of the secondary battery is about four (4) to 100 times of an electric capacity of the capacitor, and

wherein the over-voltage preventing device is an over-voltage preventing circuit including a voltage comparator for comparing a predetermined voltage and an applied voltage, a switch for flowing electricity when the applied voltage exceeds the predetermined voltage and a breeder resistor for discharging the capacitor when the switch flows the electricity.

7. The method of charging and discharging of an electric energy storage device as claimed in claim 6, wherein the capacitor is an electric double layer capacitor and the secondary battery is one of a lead acid battery, a nickel-cadmium (Ni—

Cd) battery, a nickel-metal hydride battery and a lithium ion battery.

8. The method of charging and discharging of an electric energy storage device as claimed in claim 6, wherein the over-voltage preventing device is a Zener diode.

9. The method of charging and discharging of an electric energy storage device as claimed in claim 6, wherein the over-voltage preventing device is a shunt regulator.

10. The method of charging and discharging of an electric energy storage device as claimed in claim 6, further comprising an over-discharge preventing device connected to both end portions of the secondary battery.