This problem was already recognised in the previous millenium and the manufacturer engineers (GM for the later NiMH EV1) used the conveniently available AirCo of the car to suck cold air through the pack while charging in elevated temps - that is why the charging efficiency of NiMH batteries has been suspect for long time before the Prius showed that you can do it better - they still do draw cabin air through the pack, but do not run the car's AirCo while the car is sitting still, only to cool the pack down...
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of tomw Sent: Monday, June 24, 2013 6:45 AM To: [email protected] Subject: Re: [EVDL] Air cooled vs. liquid cooled batteries and chargingstandards. "/It doesn't matter whether you liquid-cool or air-cool (or even solid-state-cool) something -- all that matters is the end-temperature you reach. In each case, you are ultimately dumping the excess heat into the surrounding air, anyway./" Sure the heat is going into the surrounding air, but a liquid-air heat exchanger permits much higher heat transfer than a finned heat sink, so it depends on the rate of heat removal required to maintain a desired temperature difference from ambient. That of course is why ice's have radiators rather than fans blowing directly on the ice. If you are using LiFePO4 cells in 115 F (46 C) ambient you can't afford a very large temperature difference between the cells and ambient due to decreased cell life at higher temperatures. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Air-cooled- vs-liquid-cooled-batteries-and-charging-standards-tp4663777p4663827.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
