Battery protection circuit

• US 6,992,463 B2
• Filed: 11/16/2004
• Issued: 01/31/2006
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Yoshio, Katsura
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): Berhanu, Samuel
• Application Number:
  US10/991,201
• Publication Number:
  US 20050242779A1
• Time in Patent Office: 441 Days
• Field of Search: 320/134, 320/136, 361/89, 361/91.1, 361/91.2, 307/112, 307/113, 307/114
• US Class Current: 320/134
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• 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 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2200/00 Safety devices for primary or secondary batteries
• CPC Class Codes: H02H 3/044 Checking correct functioning of protective arrangements, e.g. by simulating a fault for differential current circuit breakers H02H3/335
• CPC Class Codes: H02H 3/05 with means for increasing reliability, e.g. redundancy arrangements for logic circuits H03K19/003
• CPC Class Codes: H02H 3/087 for dc applications
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries

Abstract

A protection of battery system having battery cells Cell1˜Cell3, FET switches SW1, SW2 that are connected to the high-side path and control on/off state of the path, as well as fuse F1 for cutting said path, primary protection circuits 31˜34 that detect abnormalities in charging/discharging of the battery cells and turn the FET switches off, and secondary protecting controller 38 that detect abnormalities in charging/discharging of the battery cells and controls the operation of fuse F1. Secondary protecting controller 38 controls fuse F1 if there is no tendency to a decrease in abnormalities after a prescribed period of time after control of the FET switch.

Claims

1. A battery protection circuit used to control the operation of a first switch circuit and a second switch circuit inserted in series in a power supply path between battery cells and an external power source, comprising a first protecting controller, having an interface circuit for receiving a command signal output from a controller monitoring whether the voltage of the battery cells is higher than a first voltage, and generating a control signal for controlling operation of the first switch circuit,

a second protecting controller, having an over-voltage detector that detects whether the voltage of the battery cells is higher than a second voltage or higher than the first voltage, and generating a control signal for controlling the operation of the first switch circuit and a second control signal for controlling the turning off of the second switch circuit;

wherein, when the over-voltage detector of the second protecting controller detects that the voltage of the battery cells is higher than said second voltage, a control signal for turning off the first switch circuit is generated;

then, when the voltage of the battery cells remains higher than the second voltage after a prescribed time, the second control signal is generated for turning off the second switch circuit.

2. The battery protection circuit described in claim 1 wherein the first protecting controller and the second protecting controller are formed a single semiconductor chip.

3. The battery protection circuit described in claim 2 further comprising a first power source circuit that generates power source voltage for said first protecting controller from the voltage supplied from the battery cells or the voltage supplied from the external power source, and a second power source circuit that generates power source voltage for said second protecting controller from the voltage supplied from the battery cells.

4. The battery protection circuit described in claim 3 further comprising a comparator that compares the output voltage of the first power source circuit and a reference voltage, and when the comparator detects that the output voltage of said first power source circuit is higher than said reference voltage, generates a control signal for turning off the second switch circuit.

5. The battery protection circuit described in claim 2 further comprising a clock monitoring circuit that monitors a clock signal supplied from the controller, and a register for holding a first or second mode state;

wherein, when the clock signal is not supplied throughout a first period, a reset signal is supplied to the controller, and at the same time, a control signal for turning off the first switch circuit is generated;

then, if the clock signal is not supplied throughout a second period, in the first mode, a reset signal is supplied, and in the second mode, a control signal for turning off the second switch circuit is output.

6. The battery protection circuit described in claim 1 further comprising a cell balance circuit that balances the battery cell voltage by a short circuit control between electrodes of the battery cells,

and a control signal gate circuit that prohibits output of the control signal to the first switch circuit during the period when said cell balance circuit performs cell balance.

7. The battery protection circuit described in claim 1 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.

8. The battery protection circuit described in claim 7 wherein the first switch circuit comprises of NMOS transistors.

9. The battery protection circuit described in claim 3 further comprising a clock monitoring circuit that monitors a clock signal supplied from the controller, and a register for holding a first or second mode state;

wherein, when the clock signal is not supplied throughout a first period, a reset signal is supplied to the controller, and at the same time, a control signal for turning off the first switch circuit is generated;

then, if the clock signal is not supplied throughout a second period, in the first mode, a reset signal is supplied, and in the second mode, a control signal for turning off the second switch circuit is output.

10. The battery protection circuit described in claim 4 further comprising a clock monitoring circuit that monitors a clock signal supplied from the controller, and a register for holding a first or second mode state;

wherein, when the clock signal is not supplied throughout a first period, a reset signal is supplied to the controller, and at the same time, a control signal for turning off the first switch circuit is generated;

then, if the clock signal is not supplied throughout a second period, in the first mode, a reset signal is supplied, and in the second mode, a control signal for turning off the second switch circuit is output.

11. The battery protection circuit described in claim 2 further comprising a cell balance circuit that balances the battery cell voltage by a short circuit control between electrodes of the battery cells,

and a control signal gate circuit that prohibits output of the control signal to the first switch circuit during the period when said cell balance circuit performs cell balance.

12. The battery protection circuit described in claim 3 further comprising a cell balance circuit that balances the battery cell voltage by a short circuit control between electrodes of the battery cells,

and a control signal gate circuit that prohibits output of the control signal to the first switch circuit during the period when said cell balance circuit performs cell balance.

13. The battery protection circuit described in claim 4 further comprising a cell balance circuit that balances the battery cell voltage by a short circuit control between electrodes of the battery cells,

and a control signal gate circuit that prohibits output of the control signal to the first switch circuit during the period when said cell balance circuit performs cell balance.

14. The battery protection circuit described in claim 5 further comprising a cell balance circuit that balances the battery cell voltage by a short circuit control between electrodes of the battery cells,

and a control signal gate circuit that prohibits output of the control signal to the first switch circuit during the period when said cell balance circuit performs cell balance.

15. The battery protection circuit described in claim 2 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.

16. The battery protection circuit described in claim 3 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.

17. The battery protection circuit described in claim 4 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.

18. The battery protection circuit described in claim 5 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.

19. The battery protection circuit described in claim 6 wherein the first switch circuit comprises of MOS transistors, and the second switch circuit comprises fuses.