Charging method and device

• US 8,106,629 B2
• Filed: 05/06/2008
• Issued: 01/31/2012
• Est. Priority Date: 05/06/2008
• Status: Active Grant

• Current Assignee: Universal Global Scientific Industrial Company Limited (ASE Technology Holding Co., Ltd.)
• Original Assignee: Universal Scientific Industrial Co., Ltd. (ASE Technology Holding Co., Ltd.)
• Inventors: Lai, Ming-Feng, Chiu, Hsin-Hsiung
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): OMAR, AHMED H
• Application Number:
  US12/115,693
• Publication Number:
  US 20090278507A1
• Time in Patent Office: 1,365 Days
• Field of Search: 320/128, 320/162
• US Class Current: 320/128
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A charging method for a battery includes: enabling a charging device to charge the battery with a first charging voltage having a value that is increasing and a first charging current having a value that is constant; and when it is determined that the value of the first charging voltage is equal to a maximum charging voltage value of the battery, enabling the charging device to charge the battery with a second charging voltage having a value that is equal to a maximum charging voltage value of the battery, and a second charging current having a value that is decreasing. A charging device for realizing the charging method is also disclosed.

Claims

1. A charging method for a battery, comprising:

A) enabling a charging device to receive an actual voltage value and an actual current value of the battery;

B) enabling the charging device to charge the battery with a first charging voltage and a first charging current, the first charging voltage having a value that is continuously increasing, the first charging current having a value that is constant and that is not greater than a discharge current value of the battery;

C) enabling the charging device to obtain an internal resistance value of the battery based on the value of the first charging voltage, and the actual voltage value and the actual current value received in step A);

D) enabling the charging device to obtain a first predetermined threshold value based on a maximum charging voltage value of the battery and a normal charging voltage value of the battery less than the maximum charging voltage value, and the internal resistance value of the battery obtained in step C), the first predetermined threshold value being less than the discharge current value of the battery;

E) when it is determined that the value of the first charging voltage is equal to the maximum charging voltage value of the battery, enabling the charging device to charge the battery with a second charging voltage and a second charging current, the second charging voltage having a value that is constant and that is equal to the maximum charging voltage value of the battery, the second charging current having a value that is continuously decreasing;

F) when it is determined that the value of the second charging current is not greater than the first predetermined threshold value, enabling the charging device to charge the battery with a third charging voltage and the second charging current, the third charging voltage having a value that is constant and that is equal to the normal charging voltage value of the battery; and

G) when it is determined that the value of the second charging current is not greater than a second predetermined threshold value, which is less than the first predetermined threshold value, disabling the charging device from charging the battery.

2. The charging method as claimed in claim 1, wherein, in step C), the internal resistance value is equal to a difference between the value of the first charging voltage and the actual voltage value divided by the actual current value.

3. The charging method as claimed in claim 1, wherein, in step D), the first predetermined threshold value is equal to a difference between the maximum charging voltage value and the normal charging voltage value divided by the internal resistance value.

4. The charging method as claimed in claim 1, wherein the second predetermined threshold value is obtained based on the discharge current value of the battery.

5. The charging method as claimed in claim 4, wherein the second predetermined threshold value is equal to one-twentieth of the discharge current value.

6. The charging method as claimed in claim 1, wherein the charging device stores a battery specification therein, which includes the normal charging voltage value, the maximum charging voltage value, and the discharge current value of the battery.

7. A charging device for a battery, comprising:

a control unit stored with a battery specification therein, the battery specification including a normal charging voltage value, a maximum charging voltage value, and a discharge current value of the battery; and

a charging unit coupled to and controlled by said control unit so as to charge the battery in

a first charging mode, where said charging unit charges the battery with a first charging voltage and a first charging current, the first charging voltage having a value that is continuously increasing, the first charging current having a value that is constant and that is not greater than the discharge current value of the battery,

a second charging mode when it is determined by the control unit that the first charging voltage is equal to the maximum charging voltage of the battery, which is greater than the normal charging voltage value of the battery, where said charging unit charges the battery with a second charging voltage and a second charging current, the second charging voltage having a value that is constant and that is equal to the maximum charging voltage value of the battery, the second charging current having a value that is continuously decreasing, and

a third charging mode, where the charging unit charges the battery with a third charging voltage and the second charging current, the third charging voltage having a value that is constant and that is equal to the normal charging voltage value of the battery;

wherein said control unit is adapted to receive an actual voltage value and an actual current value of the battery, and is operable

through a first algorithm stored therein, to obtain an internal resistance value of the battery based on the value of the first charging voltage, and the actual voltage value and the actual current value received thereby, and

through a second algorithm stored therein, to obtain a first predetermined threshold value, which is less than the discharge current value of the battery, based on the maximum charging voltage value, the normal charging voltage value, and the internal resistance value of the battery obtained thereby;

wherein said charging unit is controlled by said control unit to charge the battery in the third charging mode only when the value of the second charging current is not greater than the first predetermined threshold value.

8. The charging device as claimed in claim 7, wherein the internal resistance value is equal to a difference between the value of the first charging voltage and the actual voltage value divided by the actual current value.

9. The charging device as claimed in claim 7, wherein the first predetermined threshold value is equal to a difference between the maximum charging voltage value and the normal charging voltage value divided by the internal resistance value.

10. The charging device as claimed in claim 7, wherein said control unit is further stored with a second predetermined threshold value therein, which is less than the first predetermined threshold value,

said charging unit being disabled from charging the battery when the value of the second charging current is not greater than the second predetermined threshold value.

11. The charging device as claimed in claim 10, wherein the second predetermined threshold value is equal to one-twentieth of the discharge current value.