Usually the internal resistance is growing much faster than the loss of capacity. So if you use the pack in very low power application you will be able to use the pack for some time (several years). This is for LCO, LMO and NMC. Maybe NCA too (cannot say for sure yet as I do not have usage data from those yet).
Basically the combination of low voltage chemistry, cool temperature during use and shallow cycles will provide long life for the cells. LFP has at least 5 to 10 years more calendar life than those mentioned above. Then again LTO-cells should have even slower rate of unhoped side reactions at the chemistry level compared to LFP. But LTO has hard time to compete against LFP net cost. Which is dirty cheap. Stationary batteries are designed for the use. Meaning their cost to buffer each kWh and provide power is much much less than the EV type cells. Currently for large utility scale units the cost to buffer is around one cent per kWh. -Jukka 2016-09-23 8:45 GMT+02:00 Michael Ross via EV <ev@lists.evdl.org>: > I believe batteries, and Li-ion as well as future designs will not degrade > much for a decade and more when properly managed. Understand that 'Lithium > batteries" covers a large and disparate group of designs. So, any comment > can be quibbled over. > > What is known now, a loss of 85% would probably be accompanied by physical > and chemical damage that might render them unreliable at greater loss. But > certainly Li-ion if managed well could be useful down to 30% SOC. > > The rub here is "well managed." Proper management will depend on the exact > electrode and electrolyte chemistry, the construction of the cell, > temperature of operation and storage, particularly at high SOC%. and so on. > > Anything we say is dependent on a host of variables. I think the body of > knowledge will grow and all these difficulties will drop in significance. > > You did not say in what application the degradation to 70% SOC would occur > but safe to assume you meant in cars. Tesla already committed to creating > rid based applications for "degraded" batteries. Their belief is that > stationary applications are far easier on the cells than mobile and > automotive apps. Allowing us to believe there is a very good chance that > car batteries will likely have a second life. > > Does anyone know how low the capacity of a battery can fall before it is no > longer > useful, and how long will that take? At least 50%, probably more. 15% is > too low for current technologies. > > For example, can the capacity shrink down to 15% SOC and still provide > useful power, how long would that take? Depends. > > It will continue to improve. > > Mike > > > On Fri, Sep 23, 2016 at 12:32 AM, Larry Gales via EV <ev@lists.evdl.org> > wrote: > > > Most scenarios assume that Lithium batteries for EVs should be replaced > > when they degrade to 70-80% of their initial capacities, after which they > > might serve as storage batteries for the grid, or a house. Does anyone > > know how low the capacity of a battery can fall before it is no longer > > useful, and how long will that take? For example, can the capacity > shrink > > down to 15% and still provide useful power, and how long would that take? > > > > > > > > Thanks, Larry > > > > -- > > Larry Gales > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/ > > attachments/20160922/84aa5308/attachment.htm> > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > Read EVAngel's EV News at http://evdl.org/evln/ > > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/ > > group/NEDRA) > > > > > > > -- > To invent, you need a good imagination and a pile of junk. > Thomas A. Edison > <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > A public-opinion poll is no substitute for thought. > *Warren Buffet* > > Michael E. Ross > (919) 585-6737 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Mobile and > Google Phone > > michael.e.r...@gmail.com > <michael.e.r...@gmail.com> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/ > attachments/20160923/7d4a7fbd/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160923/a5d67ac5/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
