An electrochemical cell is provided. The cell includes a plurality of electrode sheets separated by at least one separator sheet. A positive extension tab is attached to a current collecting tabs of positive electrode sheets, and a negative extension tab is attached to current collecting tabs of the negative electrode sheets. The dimensions of the positive extension tab and the negative extensiontab are selected such that temperature difference between positive extension tab and the negative extension tab are minimized when the electrochemical cell is in use.