[frentraken]

I was thinking myself if you could get the battery mounted outside the phone would be best, and if you could find a way of getting the phone to think it's got a battery but is connected right to the powersupply, with a relay set up so that when the car stops powering it it then switches to battery automatically(Probably cause a reset but might work) this way you get rid of the heating battery issue altogether since it isn't being charged hile in use anymore. Oh and I still don't think heatsink the battery will help much. At least unless you get a fan on there, and then you are back at where you might aswell have the peltier.