Disclosed are method and apparatus for improving battery performance by transferring waste heat generated from heat generating components to the battery that, when brought to a high temperature, attains better performance according to temperature characteristics of the battery. According to the disclosure, an electronic device capable of effecting improved battery performance comprises a central processing unit generating waste heat when being operative; a battery for supplying power to said electronic device; and thermal conducting means, first end thereof making thermal contact with said central processing unit and second end thereof making thermal contact with said battery, causing heat transfer between said central processing unit and said battery. Said waste heat generated by said central processing unit is transferred to alter the temperature of said battery such that its output voltage is stabilized and capacity enlarged. Thermal pads can be disposed between said first end of said thermal conducting means and said electronic component, or between said second end of said thermal conducting means and said battery for increasing heat transfer rate. A fan can also be incorporated to cool the central processing unit.