Charging method for secondary battery

• US 5,237,259 A
• Filed: 11/12/1991
• Issued: 08/17/1993
• Est. Priority Date: 11/13/1990
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sanpei, Akira
• Primary Examiner(s): HICKEY, ROBERT
• Application Number:
  US07/790,563
• Time in Patent Office: 644 Days
• Field of Search: 320/23, 320/24, 320/31, 320/32, 320/39, 320/40, 320/37, 320/38
• US Class Current: 320/158
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• 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

Abstract

A method of charging a secondary battery by means of a constant voltage power source for supplying a limited current. The method includes a first step of charging the secondary battery until a predetermined condition is reached, and a second step of further charging the secondary battery for a predetermined period of time after the predetermined condition is reached. Accordingly, overcharge of the secondary battery can be surely prevented.

Claims

1. A method of charging a secondary battery by means of a constant voltage power source for supplying a limited current, said method comprising a first step of charging said secondary battery until a predetermined condition is reached, and a second step of further charging said secondary battery for a first predetermined period of time after said predetermined condition is reached, wherein said predetermined condition is that a charging current of said secondary battery lowers to a first predetermined current, and further comprising a third step of repeatedly charging said secondary battery after said second step after a second predetermined period of time has elapsed until said charging current lowers to a second predetermined current and then further charging said secondary battery for a third predetermined period of time after said second predetermined current is reached.