I have discussed this in the past with Jukka and he indicated (as I expected) that the current limitations come from the choice of ingredients that is used for these cells, to be used mainly in moderate Western climates. I was inquiring about the life in Asian (especially central India) temperatures and the whole issue is a matter of having a battery engineer choose a different combination of ingredients so that the temp specs are shifted up. The record low temp in Hyderabad, India on a cold winter night is 8 deg C above freezing, so there is no problem when all temp specs are shifted up by 20 deg Celcius. (Incidentally, 86 Fahrenheit is exactly 30 deg Celcius, so my guess is that this test was done using the Celcius notation, which is common in the Scientific world. Even in the USA. The reporter will have needed to "translate" this for the US audience.) Having a battery that works without degradation between +10 and +50 deg C will be beneficial in the context of warmer areas - the +30 deg C limit as found in this study is just a choice during the formulation of the batteries that are common today and investigated here. Batteries that are targeted to work in Siberia, Alaska, north- and south poles will better be designed to shift their normal temp range down by 20 deg, so that you can address different environments with different products like it is done always if the market gets big enough to diversify.
Regards, 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 Bill Dube Sent: Wednesday, April 10, 2013 9:29 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Ambient temperature & Lithium Ion Battery Life With few exceptions, all chemical reactions happen faster at higher temperature. Thus, all batteries, including lithium-ion, age more quickly at elevated temperature. There is no magic about 86 degrees. The hotter they are, the quicker they age. Chemical reactions are (generally) governed by the Arrhenius equation. http://en.wikipedia.org/wiki/Arrhenius_equation Bill D. At 07:12 PM 4/10/2013, you wrote: >I came across this article today mentioning that Lithium Ion battery >life starts to degrade faster above 86 degrees Fahrenheit. This was >delivered by a Dr. Cugnet at the 245^th National Meeting & >Exposition of the American Chemical Society (ACS). I am skeptical >that this applies to all Lithium ion chemistries. Does anyone know >of Dr. Cugnet and what he is espousing?? > >http://www.sciencedaily.com/releases/2013/04/130410103921.htm?utm_sourc e=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28Scienc eDaily%3A+Latest+Science+News%29 >_______________________________________________ >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) _______________________________________________ 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)
