Boomer23 wrote:
OK a hopeful idea. Granted, the pack would be actively cooled during charging, at the expense of charging energy economy. ... how would that actually help improve driving range? Cars that sit unplugged in hot environments for many hours, such as in outdoor parking lots at work sites, would draw down the SOC quickly by powering their AC systems for pack cooling. If pack cooling is shut down at some point, 60%, 50%, whatever you choose, then the pack will return to hot ambient temperature quite quickly. The packs would still bake and you'd have reduced driving range by running the AC for hours before the SOC hit the cutoff.
It would not improve driving range, the purpose is to minimize battery degradation. The Volt consumes about 200Wh to keep the battery cool, even if its unplugged, a minimal use of energy. GM boasts that they are using "space age" insulation and apparently it is needed. Insulating the battery pack is crucial or you will quickly drain the battery in Phoenix.. you also want to prevent condensation from forming and that is a problem.
GM claims (and a recent study mentions it) that once the pack is discharged to 60% SOC it is fairly immune to heat degradation, thus at that point you can stop cooling the pack until it is plugged in again. True the its not exactly the same chemistry as the Leaf is using.