CIRCUITRY FOR BALANCING CHARGING OF SERIES CONNECTED BATTERY CELLS

• US 20110089902A1
• Filed: 08/30/2010
• Published: 04/21/2011
• Est. Priority Date: 10/21/2009
• Status: Abandoned Application

• Current Assignee: K2 Energy Solutions
• Original Assignee: K2 Energy Solutions
• Inventors: Sunderlin, Tim A.
• Application Number:
  US12/871,415
• Publication Number:
  US 20110089902A1
• Time in Patent Office: Days
• US Class Current: 320/122
• 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 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/16 Regulation of the charging current or voltage by variation of field
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A circuit for preventing overcharging a battery cell is disclosed. The circuit comprises a voltage detector for monitoring a voltage across a battery cell. The voltage detector is configured to determine when the voltage across the battery cell is greater than a first threshold voltage. The circuit further comprises an electronic switch responsive to the voltage detector and is configured to shunt current around the battery cell when the voltage detector has determined the battery cell voltage is greater than the first threshold voltage.

Claims

1. A circuit for preventing overcharging a battery cell comprising:

a voltage detector for monitoring a voltage across a battery cell, the voltage detector configured to determine when the voltage across the battery cell is greater than a first threshold voltage; and

an electronic switch responsive to the voltage detector and configured to shunt current around the battery cell when the voltage detector has determined the battery cell voltage is greater than the first threshold voltage.

2. The circuit of claim 1 wherein:

the voltage detector is configured to determine when the voltage across the battery cell is less than a second threshold voltage; and

the electronic switch is configured to cease shunting current around the battery cell when the voltage detector has determined the voltage across the battery cell is less than the second threshold voltage.

3. The circuit of claim 2 wherein the second threshold voltage is less than the first threshold voltage.

4. The circuit of claim 1 wherein the electronic switch comprises a semiconductor device.

5. The circuit of claim 4 wherein the electronic switch comprises a plurality of semiconductor devices coupled in parallel.

6. The circuit of claim 1 wherein the electronic switch comprises a MOSFET semiconductor device.

7. The circuit of claim 1 wherein the electronic switch comprises a plurality of MOSFET semiconductor devices coupled in parallel.

8. The circuit of claim 1 including an indicator for indicating that current is being shunted around the battery cell.

9. The circuit of claim 1 including an indicator for visually indicating that current is being shunted around the battery cell.

10. The circuit of claim 9 wherein the visual indicator comprises an LED coupled in series with the electronic switch.

11. The circuit of claim 1 including a resistor coupled in series with the electronic switch.

12. The circuit of claim 1 including a plurality of parallel coupled resistors coupled in series with the electronic switch.

13. A circuit for preventing overcharging a battery cell comprising:

a voltage detector for monitoring a voltage across a battery cell, the voltage detector configured to determine when the voltage across the battery cell is greater than a first threshold voltage and to determine when the voltage across the battery cell is less than a second threshold voltage, the second threshold voltage being less than the first threshold voltage; and

an electronic switch in the form of a MOSFET semiconductor, wherein the electronic is switch responsive to the voltage detector and is configured to shunt current around the battery cell when the voltage detector has determined the battery cell voltage is greater than the first threshold voltage and to cease shunting current around the battery cell when the voltage detector has determined the voltage across the battery cell is less than the second threshold voltage.

14. The circuit of claim 13 wherein the electronic switch comprises a plurality of MOSFET semiconductor devices coupled in parallel.

15. The circuit of claim 13 including an indicator for indicating that current is being shunted around the battery cell.

16. The circuit of claim 13 including an indicator for visually indicating that current is being shunted around the battery cell.

17. The circuit of claim 16 wherein the visual indicator comprises an LED coupled in series with the electronic switch.

18. The circuit of claim 13 including a resistor coupled in series with the electronic switch.

19. The circuit of claim 13 including a plurality of parallel coupled resistors coupled in series with the electronic switch.