Memory effect sensitive battery monitoring apparatus for electric vehicles

A battery condition monitoring system comprising:

• battery terminal voltage determining means for determining a terminal voltage of a battery under discharge of a given current;
• consumption determining means for determining a consumption of electric energy stored in the battery;
• terminal voltage change rate determining means for determining a rate of change in terminal voltage of the battery determined in said battery terminal voltage determining means relative to change in consumption of electric energy determined by said consumption determining means;
• and
• battery condition determining means for determining conditions of the battery, said battery condition determining means determining that memory effect is occurring in the battery when a difference between the rate of change determined in said terminal voltage change rate determining means and a reference rate representing a rate of change in terminal voltage of a normal battery relative to change in consumption of electric energy, exceeds a given value.