Recharge battery using heat
An electrochemical cell works on the principle that the Gibbs free energy gets converted into electrical energy by making the electron transfer indirect. This is done by itself to make the 'heat energy' that would normally be released in a redox reaction into 'electrical energy' so ideally heat shouldn't be lost. 

Also you say you want to charge the cell by heating it so as to make the reaction go in the opposite direction. But for a spontaneous cell reaction, increasing the temperature makes the Gibbs free energy more negative and $\Delta G^\circ = -nFE^\circ$ ($E^\circ$ is standard cell potential).

So the $E^\circ$ value increases, and so does the concentration (because of backwards reaction), so the cell doesn't actually get charged up. 

Ideally just charge it by passing current in the other direction.