Battery power source protecting device for an electromotive device

• US 6,388,426 B1
• Filed: 05/18/2001
• Issued: 05/14/2002
• Est. Priority Date: 09/21/1999
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Tanaka, Kenji, Yokoo, Sadaaki, Kasai, Kanako, Ura, Hironori
• Primary Examiner(s): Toatley, Gregory
• Application Number:
  US09/850,736
• Time in Patent Office: 361 Days
• Field of Search: 320/136, 320/162, 320/150, 320/134
• US Class Current: 320/136
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

A control circuit measures the battery voltage, intermediate voltage and discharge current of a rechargeable battery comprising a plurality of cells connected in series, at prescribed time intervals, and detects values for these parameters based on running averages for a prescribed number of measurement operations, while also detecting the battery temperature. If the battery temperature becomes equal to or greater than a prescribed temperature, or if the discharge current is an excessive current equal to or greater than a prescribed value, or if the battery voltage is equal to or less than a prescribed value, or if it is judged, from detection of the intermediate voltage that the balance between cell capacities has declined, then the control circuit halts discharge from the rechargeable battery by switching an FET to OFF.

Claims

1. A battery power source device comprising:

a rechargeable battery having a discharge circuit; and

a discharge control device that controls discharge of said rechargeable battery, wherein said discharge control device measures the voltage and discharge current of said rechargeable battery a prescribed number of times at prescribed time intervals, detects a battery voltage value and a discharge current value for each of said prescribed number of measurement operations from running averages for said measurement operations, detects the battery temperature of said rechargeable battery, and shuts off the discharge circuit of said rechargeable battery, when said battery voltage value, discharge current value and battery temperature satisfy any one of the following conditions;

(1) when said battery voltage value at most equal to a predetermined undercut voltage value is detected consecutively for at least a prescribed number of measurement operations;

(2) when said discharge current value at least equal to a predetermined excessive current value is detected consecutively for at least a prescribed number of measurement operations; and

(3) when said battery temperature is at least equal to a predetermined temperature.

2. The battery power source device according to claim 1, wherein the undercut voltage value is a voltage value specified in accordance with the discharge current value and the battery temperature.

3. The battery power source device according to claim 1, wherein the shut-off state of the discharge circuit is locked and a recharge advice display recommending recharging is implemented, when the battery voltage value or the unit voltage value falls below the undercut voltage value.

4. The battery power source device according to claim 1, further comprising a control conditions setting device that changes the setting values for the shutting off of the discharge circuit.

5. A battery power source device comprising:

a rechargeable battery, in which a discharge circuit is formed, said rechargeable battery comprising a plurality of cells connected in series; and

a discharge control device that controls discharge of said rechargeable battery, wherein said discharge control device measures unit voltages of each cell and each block of a plurality of cells, and the voltage and discharge current of said rechargeable battery, a prescribed number of times at prescribed time intervals, detects unit voltage values, a battery voltage value and a discharge current value respectively for each of said prescribed number of measurement operations from running averages for said measurement operations, detects the battery temperature of said rechargeable battery, and shuts off the discharge circuit of said rechargeable battery, when said unit voltage values, battery voltage value, discharge current value and battery temperature satisfy any one of the following conditions;

(1) when the difference between the smallest value and the next to smallest value of the respective unit voltage values, which is at least equal to dedetermined allowable value, is consecutively detected for at least a prescribed number of measurement operations;

(2) when said battery voltage value at most equal to a predetermined undercut voltage value is consecutively detected for at least a prescribed number of measurement operations;

(3) when said discharge current value at least equal to a predetermined current value is consecutively detected for at least a prescribed number of measurement operations; and

(4) when said battery temperature is at least equal to predetermined temperature.

6. The battery power source device according to claim 5, wherein the undercut voltage value is a voltage value specified in accordance with the discharge current value and the battery temperature.

7. The battery power source device according to claim 5, wherein the undercut voltage value is a value obtained by multiplying the number of cells connected in series for constituting the rechargeable battery with a voltage value specified for each cell in accordance with the discharge current value.

8. The battery power source device according to claim 5, wherein the shut-off state of the discharge circuit is locked and a recharge advice display recommending recharging is implemented, when the battery voltage value or the unit voltage value falls below the undercut voltage value.

9. The battery power source device according to claim 5, further comprising a control conditions setting device that changes the setting values for the shutting off of the discharge circuit.

10. An electromotive device using a battery power source device as a driving power source to drive a motor in rotation, said battery power source device comprising a rechargeable battery having a discharge circuit:

and

a discharge control device that controls discharge of said rechargeable battery, wherein said discharge control device measures a voltage and discharge current of said rechargeable battery a prescribed number of times at prescribed time intervals when said electromotive device is in an ON state, detects a battery voltage value and a discharge current value for each of said prescribed number of measurement operations, from running averages for each of said measurement operations, detects the battery temperature of the rechargeable battery, and shuts off the discharge circuit of the rechargeable battery, when said battery voltage value, discharge current value and battery temperature satisfy any one of the following conditions;

(1) when said battery voltage value at most equal to a predetermined undercut voltage value is detected consecutively for at least a prescribed number of measurement operations;

(2) when said discharge current value at least equal to a predetermined current value is consecutively detected for at least a prescribed number of measurement operations; and

(3) when said battery temperature is at least equal to a predetermined temperature.

11. The electromotive device using a battery power source device according to claim 10, wherein the undercut voltage value is a voltage value specified in accordance with the discharge current value and battery temperature.

12. The electromotive device using a battery power source device according to claim 10, further comprising a reset device, wherein the shut-off operation of the discharge circuit can be cancelled by an OFF operation of the electromotive device or by a reset operation of said reset device.

13. The electromotive device using a battery power source device according to claim 10, wherein the shut-off state of the discharge circuit is locked and a recharge advice display recommending recharging is implemented, when the battery voltage value or the unit voltage value falls below the undercut voltage value.

14. The electromotive device using a battery power source device according to claim 10, further comprising a control conditions setting device that changes the setting values for the shutting off of the discharge circuit.

15. The electromotive device using a battery power source device according to claim 10, wherein the rechargeable battery comprises one of a nickel metal hydride battery and a nickel cadmium battery.

16. An electromotive device using a battery power source device as a driving power source to drive a motor in rotation, said battery power source device comprising a rechargeable battery having a discharge circuit, said rechargeable battery comprising a plurality of cells connected in series;

and

a discharge control device that controlls discharge of said rechargeable battery, wherein said discharge control device measures unit voltages of one of each cell and each block of a plurality of cells, and the voltage and discharge current of said rechargeable battery, a prescribed number of times at prescribed time intervals, when said electromotive device is in an ON state, detects unit voltage values, a battery voltage value and a discharge current value for each of said prescribed number of measurement operations from running averages for said measurement operations, detects the battery temperature of the rechargeable battery, and shuts off the discharge circuit of said rechargeable battery, when said unit voltage values, battery voltage value, discharge current value and battery temperature satisfy any one of the following conditions;

(1) when the difference between the smallest value and the next to smallest value of the respective unit voltage values, is at least equal to a predetermined allowable value, is consecutively detected for at least a prescribed number of measurement operations;

(2) when said battery voltage value equal to at most a predetermined undercut voltage value is consecutively detected for at least a prescribed number of measurement operations;

(3) when said discharge current value at least equal to a predetermined current value is consecutively detected for at least a prescribed number of measurement operations; and

(4) when said battery temperature is at least equal to a predetermined temperature.

17. The electromotive device using a battery power source device according to claim 16, wherein the undercut voltage value is a voltage value specified in accordance with the discharge current value and battery temperature.

18. The electromotive device using a battery power source device according to claim 16, wherein the undercut voltage value is a value obtained by multiplying the number of cells connected in series for constituting the rechargeable battery with a voltage value specified for each cell in accordance with the discharge current value.

19. The electromotive device using a battery power source device according to claim 16, further comprising a reset device, wherein the shut-off operation of the discharge circuit can be cancelled by an OFF operation of the electromotive device or by a reset operation of said reset device.

20. The electromotive device using a battery power source device according to claim 16, wherein the shut-off state of the discharge circuit is locked and a recharge advice display recommending recharging is implemented when the battery voltage value or the unit voltage value falls below the undercut voltage value.

21. The electromotive device using a battery power source device according to claim 16, further comprising a control conditions setting device that changes the setting values for shutting off of the discharge circuit.

22. The electromotive device using a battery power source device according to claim 16, wherein the rechargeable battery comprises one of a nickel metal hydride battery and a nickel cadmium battery.