Patent ID: 6639386
Filing Date: 2003-10-28
Classification: H02J

Abstract:
A rechargeable battery device, comprising:battery voltage detection means which determines the terminal voltage of a rechargeable battery, switching means which switches on and off the charging current of said rechargeable battery continuously or intermittently, a memory which stores the battery voltage Von of said rechargeable battery detected by said battery voltage detection means immediately before said charging current is switched off by said switching means, internal resistance determination means which determines a value corresponding to the internal resistance R of said rechargeable battery, from the open battery voltage Voff of said rechargeable battery detected by said battery voltage detection means when said charging current is switched off by said switching means and from the battery voltage Von stored in said memory, and battery life determination means which determines the operation life of said rechargeable battery, from the value Z(int) corresponding to the early-stage internal resistance R of said rechargeable battery obtained by said internal resistance determination means when said rechargeable battery was first put to use and value Z(now) corresponding to the latest internal resistance R obtained by said internal resistance determination means.