Yeah, I wouldn't say prove either. But testing can be far better than the old tried, and not very good cycling tests.
The program a the Dahn Lab at Dalhousie University ( https://www.dal.ca/diff/dahn/publications.html ) developed super sensitive methods for examining Li ion batteries. They can detect deterioration of the cells in a relatively short amount of time and correlate that to life cycle. Did they do that with LiFePO? I am not sure about that. His grad students have gone on to work for Tesla (Aaron Smith as engineer in charge of cell life), and to develop testing equipment for sale to battery manufacturers (Chris Burns, Novonix Battery Testing Services Inc.). See: 422. A.J. Smith, J.C. Burns, S. Trussler and J.R. Dahn, Precision Measurements of the Coulombic Efficiency of Lithium-ion Batteries and of Electrode Materials for Lithium-ion Batteries, J. Electrochem. Soc. 157, A196-A202 (2010). Definitely better than the anecdotal evidence and poorly conceived cycle testing that was and probably still is prevalent at LiFePO manufacturers. (Didn't this thread drift to LiFePO and a claim of 10000 cycle life?) I tried to get a sense from Chinese large cell manufactures and pack constructors if they understood what their testing did, and to see if they were aware of what was being developed. They were pretty mystified by my questions; could be I never had conversation with the right people, but I think they were just happy to have sales without worrying to much about testing representing the real world. LiFePO cells can be long lasting, but they are easily damaged if temperatures in the 90F range are experienced while the cells are fully charged. My own anecdotal evidence bore this out. I ruined packs charging them in a hot location with far fewer than 10000 cycles. On Tue, Sep 11, 2018 at 7:04 PM Jan Steinman via EV <ev@lists.evdl.org> wrote: > > From: "George Tyler" <g...@tylernz.com> > > > > it is all proven science, you can prove a lifetime of 10 years > > "Prove" is a pretty strong word, a word that scientists rarely use. > "Proofs" are for mathematicians and lawyers; scientists generally speak of > "evidence." > > If you'd say, "There's a pretty high confidence level that these batteries > will last ten years," I wouldn't argue. But the only way you "prove" that a > battery will last ten years is to use it for ten years. > > Jan > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Michael E. Ross (919) 585-6737 Land (919) 901-2805 Cell and Text (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Tablet, Google Phone and Text -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180911/09a18fbb/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
