TEMPERATURE COMPENSATED CURRENT MEASURING DEVICE AND BATTERY PACK USING THE SAME

• US 20090087725A1
• Filed: 09/26/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: SIM, Sesub
• Granted Patent: US 8,173,287 B2
• Time in Patent Office: Days
• US Class Current: 429/90
• CPC Class Codes: G01R 1/203 Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R
• CPC Class Codes: G01R 1/44 Modifications of instruments for temperature compensation
• CPC Class Codes: G01R 19/32 Compensating for temperature change
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC

Abstract

A battery pack, and more particularly, a temperature compensated current measuring device which can accurately measure an actual current flowing in a circuit of a charging/discharging path in the battery pack. The temperature compensated current measuring device includes a conductor in which current flows, a temperature sensor disposed around the conductor to measure a temperature of the conductor, and a temperature compensated current detection circuit part electrically connected to two positions of the conductor to measure a voltage between the two positions, electrically connected to the temperature sensor to measure a temperature of the conductor, and measuring the current flowing in the conductor by using the measured temperature and the voltage as an input signal. Thus, it is possible to accurately calculate an actual charging/discharging current with the temperature compensated current measuring device and effectively control the charging capacity of the battery pack.

Claims

1. A temperature compensated current measuring device comprising:

a conductor in which current flows;

a temperature sensor disposed around the conductor, to measure a temperature of the conductor; and

a temperature compensated current detection circuit part electrically connected to two positions of the conductor, to measure a voltage between the two positions, electrically connected to the temperature sensor to measure temperature of the conductor, and to measure the current, flowing in the conductor, by using the measured temperature and the voltage as an input signal.

2. The device according to claim 1, wherein the conductor is extended along one direction with a uniform thickness and a width using the same material, and a resistance value of the conductor increases according to an increase of the length and the resistance value thereof changes according to the temperature.

3. The device according to claim 1, wherein the conductor is formed of any one selected from the group consisting of copper (Cu), nickel (Ni), and gold (Au).

4. The device according to claim 1, wherein the conductor is formed in a conductive wire.

5. The device according to claim 1, wherein the conductor is a printed circuit pattern formed on an insulating substrate.

6. The device according to claim 1, wherein the conductor, the temperature sensor, and the temperature compensated current detection circuit part are on the same insulating substrate.

7. The device according to claim 1, wherein the temperature sensor is formed in one of a thermistor and an integrated circuit type temperature sensor.

8. The device according to claim 1, wherein the temperature compensated current detection circuit part comprises:

a voltage detection part connected to the two positions of the conductor, to measure the voltage between the two positions;

a temperature detection part electrically connected to the temperature sensor, to detect a voltage value of the temperature measured by the temperature sensor; and

an arithmetic operation part converting the voltage value corresponding to the temperature, measured by the temperature detection part, into a resistance value of the conductor, and calculating a current capacity, flowing in the conductor, by using the resistance value and the voltage between the two positions of the conductor measured by the voltage detection part.

9. The device according to claim 1, wherein the temperature compensated current detection circuit part comprises:

a transducer electrically connected to the temperature sensor to convert a detected resistance value of the temperature sensor into a voltage value;

an analog-to-digital (A/D) converter connected to the two positions of the conductor, to convert a measured analog voltage into a digital voltage; and

a micro controller unit electrically connected to the transducer and the A/D converter, to receive the voltage value output from the transducer and the A/D converter.

10. A battery pack comprising:

a rechargeable battery;

a charging/discharging switching element electrically connected to a high-current of the battery;

a conductor electrically connected to a high-current path in which current for charging/discharging of the battery flows;

a temperature sensor disposed around the conductor, to measure a temperature of the conductor; and

a charging/discharging control circuit electrically connected to the battery, to measure a voltage, electrically connected to two positions of the conductor, to measure a voltage between the two positions, electrically connected to the temperature sensor, to measure the temperature of the conductor and calculate the current flowing in the conductor by using the voltage and the temperature, measured from the conductor, as an input signal, and to adjust a current capacity flowing in the charging/discharging switching element.

11. The battery pack according to claim 10, wherein the charging/discharging control circuit comprises:

a temperature compensated current detection part comprising;

a voltage detection part connected to the two positions of the conductor, to measure the voltage between the two positions;

a temperature detection part electrically connected to the temperature sensor, to detect a voltage value of the temperature measured by the temperature sensor; and

an arithmetic operation part converting the voltage value corresponding to the temperature measured by the temperature detection part into a resistance value of the conductor and calculating a current capacity, flowing in the conductor, by using the resistance value and the voltage between the two positions of the conductor measured by the voltage detection part; and

a charging/discharging part electrically connected to the battery, to measure a voltage of the battery and electrically connected to the charging/discharging switching element and the high-current path for charging/discharging of the battery, to receive a current value, calculate a charging/discharging capacity from the temperature compensated current detection part, and adjust a current capacity flowing in the charging/discharging switching element.

12. The battery pack according to claim 10, wherein the charging/discharging control circuit comprises:

a temperature compensated current detection part comprising;

a transducer electrically connected to the temperature sensor, to convert a detected resistance value of the temperature sensor into a voltage value;

an A/D converter connected to the two positions of the conductor, to convert a measured analog voltage into a digital voltage; and

a micro controller unit electrically connected to the transducer and the A/D converter to receive the voltage value output from the transducer and the A/D converter; and

a charging/discharging part electrically connected to the battery, to measure a voltage of the battery and electrically connected to the charging/discharging switching element and switch on/off the charging/discharging switching element, and receive a current value of the battery calculated charging/discharging capacity from the temperature compensated current detection part, and adjust a current capacity flowing in the charging/discharging switching element.

13. The battery pack according to claim 10, wherein the charging/discharging switching element is formed in a field effect transistor (FET).

14. The battery pack according to claim 10, wherein the conductor is formed in a conductive wire.

15. The battery pack according to claim 10, wherein the conductor is a printed circuit pattern formed on an insulating substrate.

16. The battery pack according to claim 10, wherein the conductor is formed of one selected from the group consisting of copper (Cu), nickel (Ni), and gold (Au).

17. The battery pack according to claim 10, wherein the conductor is extended along one direction with a uniform thickness and a width using the same material, and a resistance value of the conductor increases according to an increase of the length and the resistance value thereof changes according to the temperature.

18. The battery pack according to claim 10, wherein the temperature sensor is formed in one of a thermistor or an integrated circuit type temperature sensor.