Rechargeable battery device equipped with life determination function

A rechargeable battery device comprising:

• battery voltage detection means which determines the terminal voltage of a rechargeable battery,
• current detection means which detects the charging current to said 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 determined by said battery voltage detection means immediately before said charging current is switched off by said switching means, together with the charging current Ion detected by said current detection means at the same timing,
• 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, from the charging current Joff detected by said current detection means at the same timing, and from the battery voltage Von and the charging current Ion 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 from the value Z(now) corresponding to the latest internal resistance R of said rechargeable battery obtained by said internal resistance determination means.

A rechargeable battery device, comprising:

• voltage detection means which detects the terminal voltage of each group of a single or multiple rechargeable battery cells in a battery block, wherein a plurality of rechargeable battery cells are connected in series,
• fluctuation determination means which determines the fluctuation of the terminal voltages of said groups,
• unbalance detection means which generates an unbalance signal when the fluctuation of said group terminal voltages during or after the charging of said rechargeable battery exceeds a predetermined level, and
• battery life determination means which determines the operation life of said battery block on the basis of the unbalance signal.