Rechargeable battery charging method

• US 5,442,274 A
• Filed: 08/26/1993
• Issued: 08/15/1995
• Est. Priority Date: 08/27/1992
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tamai, Mikitaka
• Primary Examiner(s): Peckman, Kristine L.
• Application Number:
  US08/111,976
• Time in Patent Office: 719 Days
• Field of Search: 320/20, 320/21, 320/31, 320/32, 320/39, 320/40, 320/22, 320/23, 320/24
• US Class Current: 320/146
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A hysteresis battery charging method repeats peak and trough voltage and current waveforms taking the battery to a temporary over-voltage state during peak charging. This method achieves rapid recharge while avoiding battery performance degradation. Constant current charging or quasi-constant current charging is performed during peak charging. During troughs, charging is either suspended or reduced from that during peak charging. After battery capacity has reached a set value by hysteresis charging, an optimum voltage is maintained by constant voltage charging.

Claims

1. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging a rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until a battery voltage of the rechargeable battery becomes a first voltage that is greater than a second voltage;

(b) repeating a process of constant current charging the rechargeable battery at the one of the prescribed constant current and the prescribed quasi-constant current and of then pausing the constant current charging of the rechargeable battery; and

(c) constant voltage charging the rechargeable battery at the second voltage after step (b);

further comprising detecting a time that elapses as the battery voltage drops from the first voltage toward the second voltage during the pausing of the constant current charging in step (b), and wherein the constant voltage charging in step (c) starts when the detected time becomes greater than or equal to a prescribed time.

2. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging a rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until a battery voltage of the rechargeable battery becomes a first voltage that is greater than a second voltage;

(b) repeating a process of constant voltage charging the rechargeable battery at the first voltage and of then pausing the constant voltage charging of the rechargeable battery; and

(c) constant voltage charging the rechargeable battery at the second voltage after step (b);

further comprising detecting a charging current of the rechargeable battery during the pausing of the constant voltage charging at the first voltage in the step (b), and wherein the constant voltage charging at the second voltage in the step (c) starts when the charging current becomes less than or equal to a prescribed current.

3. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging a rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until a battery voltage of the rechargeable battery becomes a first voltage that is greater than a second voltage;

(b) repeating a process of constant voltage charging the rechargeable battery at the first voltage and of then pausing the constant voltage charging of the rechargeable battery; and

(c) constant voltage charging the rechargeable battery at the second voltage after step (b);

wherein the constant voltage charging at the second voltage in the step (c) starts after the constant voltage charging of the rechargeable battery at the second voltage in the step (b) is performed for a prescribed time period.

4. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging a rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes a second voltage;

(b) repeating a process of constant current charging the rechargeable battery at the one of the prescribed constant current and the prescribed quasi-constant current and of then constant voltage charging the rechargeable battery at the second voltage; and

(c) detecting a charging current of the rechargeable battery during constant voltage charging at the second voltage in the step (b) and constant voltage charging at the second voltage when the charging current becomes less than or equal to a set current.

5. A rapid rechargeable battery charging method as recited in claim 4, wherein the constant current charging in the step (b) is performed so that the battery voltage does not exceed a first voltage which is greater than the second voltage.

6. A rapid rechargeable battery charging method as recited in claim 4, wherein the constant voltage charging in the step (b) is performed after discharging the rechargeable battery until the battery voltage becomes the second voltage.

7. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging the rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes a second voltage;

(b) repeating a process of constant current charging the rechargeable battery at the one of the prescribed constant current and the prescribed quasi-constant current and of then pausing the constant current charging of the rechargeable battery; and

(c) detecting the battery voltage during each pausing of the constant current charging in the step (b), and constant voltage charging at the second voltage when the battery voltage becomes greater than or equal to the second voltage;

wherein the constant current charging in the step (b) is performed so that the battery voltage does not exceed a first voltage which is greater than the second voltage.

8. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging the rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes a second voltage;

(b) repeating a process of constant current charging the rechargeable battery at the one of the prescribed constant current and the prescribed quasi-constant current and of then pausing the constant current charging of the rechargeable battery; and

(c) detecting the battery voltage during each pausing of the constant current charging in the step (b), and constant voltage charging at the second voltage when the battery voltage becomes greater than or equal to the second voltage;

wherein the constant voltage charging in the step (b) is performed by discharging the rechargeable battery until the battery voltage becomes the second voltage.

9. A rapid rechargeable battery charging method, which comprises the steps of:

(a) charging the rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes a second voltage;

(b) repeating a process of constant voltage charging the rechargeable battery at a first voltage that is greater than the second voltage, and of then constant voltage charging the rechargeable battery at the second voltage; and

(c) detecting charging current of the rechargeable battery during constant voltage charging at the second voltage in the step (b), and constant voltage charging the rechargeable battery at the second voltage when the charging current becomes less than or equal to a set current.

10. A rapid rechargeable battery charging method as recited in claim 9, wherein the constant voltage charging at the first voltage in the step (b) is performed so that charging of the rechargeable battery is only at a set charging capacity.

11. A rapid rechargeable battery charging method as recited in claim 10, wherein the set charging capacity is from 0.05 to 5% of the rechargeable battery capacity.

12. A method of rapidly charging a rechargeable battery to a second voltage, which comprises the steps of:

(a) charging the rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes the second voltage;

(b) repeating a process of constant voltage charging the rechargeable battery at a first voltage that is greater than the second voltage and of then pausing the constant voltage charging of the rechargeable battery; and

(c) detecting a time that elapses as the battery voltage of the rechargeable battery drops toward the second voltage during each pausing of the constant voltage charging of the rechargeable battery in the step (b), and constant voltage charging the rechargeable battery at the second voltage when the detected time becomes greater than or equal to a prescribed time.

13. A method of rapidly charging the rechargeable battery as recited in claim 12, wherein constant voltage charging at the first voltage in the step (b) is performed so that charging of the rechargeable battery is only at a set charging capacity.

14. A method of rapidly charging the rechargeable battery as recited in claim 13, wherein the set charging capacity is from 0.05 to 5% of the rechargeable battery capacity.

15. A method of rapidly charging a rechargeable battery to a second voltage, which comprises the steps of:

(a) charging a rechargeable battery at one of a prescribed constant current and a prescribed quasi-constant current until the battery voltage of the rechargeable battery becomes at least the second voltage;

(b) repeating a process of charging the rechargeable battery so that the battery voltage is greater than the second voltage and does not exceed a first voltage which is greater than the second voltage, and of then charging the rechargeable battery so that the battery voltage drops to at least the second voltage; and

(c) constant voltage charging the rechargeable battery at the second voltage after step (b).