BATTERY CHARGING SYSTEM AND METHOD

• US 20110215769A1
• Filed: 07/18/2010
• Published: 09/08/2011
• Est. Priority Date: 03/08/2010
• Status: Abandoned Application

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: HUANG, CHUNG-HSIN
• Application Number:
  US12/838,484
• Publication Number:
  US 20110215769A1
• Time in Patent Office: Days
• US Class Current: 320/145
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

An exemplary battery charging system includes a temperature sensor, a voltage measuring device, a processor and a charger. The temperature sensor is used for continuously sensing the current temperature of a rechargeable battery. The voltage measuring device is used for continuously measuring the current voltage U of the rechargeable battery. The processor is used for comparing the current temperature T with two temperature thresholds and comparing the current voltage U with two cut-off voltages, and generating a PWM control signal to the charger based on the results of the comparisons. The charger is used for charging the battery. When T reads as normal, the charger charges the battery using a first average current I1 and stops charging at U1. When T reads as hot, the charger charges the battery using a second average current I2 and stops charging at U2, wherein I1>I2, U1>U2.

Claims

1. A battery charging system for charging a rechargeable battery, comprising:

a temperature sensor configured to be positioned on an outer surface of the rechargeable battery and configured for continuously sensing a current temperature T of the rechargeable battery;

a voltage measuring device configured to be electrically connected to both a positive electrode and a negative electrode of the rechargeable battery and configured for continuously measuring a current voltage U of the rechargeable battery;

a processor storing a first temperature threshold T1 and a second temperature threshold T2, and a first cut-off voltage U1 and a second cut-off voltage U2, wherein T1<

T2, and U1>

U2, the processor configured for;

comparing the current temperature T with the first and second temperature thresholds T1 and T2, and comparing the current voltage U with the first and second cut-off voltages U1 and U2; and

generating a PWM control signal according to the results of the temperature comparisons and the results of the voltage comparisons; and

a charger electrically connected to the processor and configured for electrical connection to a power supply, and further configured for providing a charging current to the rechargeable battery according the PWM control signal of the processor;

wherein when the current temperature T falls into the range T1˜

T2, the charger is configured for charging the rechargeable battery using a first average current I1;

if the current voltage U reaches the first cut-off voltage U1 while the current temperature T remains in the range T1˜

T2, the charger is configured for stopping charging the rechargeable battery;

if the current temperature T exceeds the range T1˜

T2 before the current voltage U reaches the first cut-off voltage U1, the charger is configured for charging the rechargeable battery using a second average current I2, wherein I1>

I2;

if the current voltage U reaches the second cut-off voltage U2 before the current temperature T exceeds the range T1˜

T2, the charger is configured for stopping charging the rechargeable battery.

2. The battery charging system in claim 1, wherein the processor also stores a third temperature threshold T3 and a fourth temperature threshold T4, and T3<

T1<

T2<

T4;

if the current temperature T falls into either of the ranges T3˜

T1 or T2˜

T4 before the current voltage U reaches the first cut-off voltage U1, the charger is configured for charging the rechargeable battery using the second average current I2;

if the current voltage U reaches the second cut-off voltage U2 when the current temperature T is in either of the ranges T3˜

T1 or T2˜

T4, the charger is configured for stopping charging the rechargeable battery; and

if the current temperature T exceeds the range T3˜

T4 before the current voltage U reaches the second cut-off voltage U2, the charger is configured for stopping charging the rechargeable battery.

3. The battery charging system in claim 1, wherein T1 is about 10°

C., T2 is about 45°

C., T3 is about 0°

C., T4 is about 60°

C., U1 is about 4.05V, and U2 is about 4.2V.

4. The battery charging system in claim 1, wherein the processor comprises a storing module, a temperature comparing module, a voltage comparing module, and a controlling module, the storing module stores the first and second temperature thresholds T1, T2 and the first and second cut-off voltages U1, U2;

the temperature comparing module is configured for comparing the current temperature T with the first and second temperature thresholds T1 and T2;

the voltage comparing module is configured for comparing the current voltage U with the first and second cut-off voltages U1 and U2; and

the controlling module is configured for generating the PWM control signal according to the temperature comparison results and the voltage comparison results.

5. The battery charging system in claim 1, wherein the processor is configured to control the charger by adjusting the duty cycle of the PWM control signal.

6. The battery charging system in claim 5, wherein the charger includes a charging module and a current adjusting module, the charging module is configured for providing charging current to the rechargeable battery, and the current adjusting module is configured for adjusting the charging current according the PWM control signal of the processor.

7. The battery charging system in claim 6, wherein the current adjusting module comprises a metal oxide semiconductor field effect transistor.

8. The battery charging system in claim 7, wherein the current adjusting module comprises a base, a collector and an emitter, the base is arranged for receiving the PWM signal of the processor;

the collector is configured for coupling to the rechargeable battery, and the emitter is coupled with the charging module.

9. The battery charging system in claim 1, wherein the rechargeable battery is a lithium battery.

10. The battery charging system in claim 1, wherein the voltage measuring device is a voltmeter.

11. A battery charging system for charging a rechargeable battery, comprising:

a temperature sensor configured to be positioned on an outer surface of the rechargeable battery and configured for continuously sensing a current temperature T of the rechargeable battery;

a voltage measuring device configured to be electrically connected to both a positive electrode and a negative electrode of the rechargeable battery and configured for continuously measuring a current voltage U of the rechargeable battery;

a processor storing a first temperature threshold T1 and a second temperature threshold T2, and a first cut-off voltage U1 and a second cut-off voltage U2, wherein T1<

T2, and U1>

U2, the processor configured for;

comparing the current temperature T with the first and second temperature thresholds T1 and T2, and comparing the current voltage U with the first and second cut-off voltages U1 and U2; and

generating a PWM control signal according to the results of the temperature comparisons and the results of the voltage comparisons; and

a power supply for providing electrical power; and

a charger electrically connected to the processor and the power supply, and configured for providing a charging current to the rechargeable battery according the PWM control signal of the processor;

wherein when the current temperature T falls into the range T1˜

T2, the charger is configured for charging the rechargeable battery using a first average current I1;

if the current voltage U reaches the first cut-off voltage U1 while the current temperature T remains in the range T1˜

T2, the charger is configured for stopping charging the rechargeable battery;

if the current temperature T exceeds the range T1˜

T2 before the current voltage U reaches the first cut-off voltage U1, the charger is configured for charging the rechargeable battery using a second average current I2, wherein I1>

I2;

if the current voltage U reaches the second cut-off voltage U2 before the current temperature T exceeds the range T1˜

T2, the charger is configured for stopping charging the rechargeable battery.

13. The battery charging method in claim 11, further comprising comparing the current temperature T with a predetermined third temperature threshold T3 and a predetermined fourth temperature threshold T4, wherein T3<

T1<

T2<

T4; and

charging the rechargeable battery using the second average current I2 when the current temperature T falls into either of the ranges T3˜

T1 or T2˜

T4 before the current voltage U reaches the first cut-off voltage U1; and

if the current voltage reaches the second cut-off voltage U2 when the current temperature T is in either of the ranges T3˜

T1 or T2˜

T4, stopping charging the rechargeable battery; and

if the current temperature T exceeds the range T3˜

T4 before the current voltage reaches the second cut-off voltage U2, stopping charging the rechargeable battery.

14. The battery charging method in claim 13, wherein T1 is about 10°

C., T2 is about 45°

C., T3 is about 0°

C., T4 is about 60°

C., U1 is about 4.05V, and U2 is about 4.2V.

12. A battery charging method for a rechargeable battery, the method comprising:

sensing a current temperature T of the rechargeable battery and measuring a current voltage U of the rechargeable battery;

comparing the current temperature T of the rechargeable battery with a predetermined first temperature threshold T1 and a predetermined second temperature threshold T2, and comparing the current voltage U of the rechargeable battery with a predetermined first cut-off voltage U1 and a predetermined second cut-off voltage U2, wherein T1<

T2 and U1>

U2, and then sending a pulse-width modulation (PWM) control signal according to the temperature comparison results and the voltage comparison results; and

charging the rechargeable battery using a first average current I1 when the current temperature T falls into the range T1˜

T2; and

if the current voltage U reaches the first cut-off voltage U1 while the current temperature T remains in the range T1˜

T2, stopping charging the rechargeable battery;

if the current temperature T exceeds the range T1˜

T2 before the current voltage U reaches the first cut-off voltage U1, charging the rechargeable battery using a second average current I2, wherein I1>

I2; and

if the current voltage U reaches the second cut-off voltage U2 before the current temperature T exceeds the range T1˜

T2, stopping charging the rechargeable battery.