Other references: This one is free and downloadable (has some neat micrographic images): Direct *in situ* measurements of Li transport in Li-ion battery negative electrodes http://www.sciencedirect.com/science/article/pii/S0009261409015462 An online presentation of the same stuff: http://lithiumbatteryresearch.com/Plating.php
On Thu, Jan 30, 2014 at 2:19 PM, Michael Ross <[email protected]>wrote: > I don't think there is any issue charging at 32°F. At any rate, you can > even charge at -4°F (-20°C) if you reduce the charge rate. What the rate > should be for a particular battery, I don't know. Pretty low like maybe > 0.1C. I am not saying to risk this. > > This is all kind of sketchy because there are a lot of papers on it, but > they are written about this and that cell type, this and that electrolyte. > It is, as they say, a problem of "kinetics." When it is cold the > electrolyte may be more viscous than ideal (there are thin electrolytes > used, but we have little knowledge of what our Chinese benefactors are up > to). The ions have a hard time getting through the interface between the > anode and the electrolyte. If the electromotive force is great then the Li > simply pile up before reaching the anode (plating). This physically blocks > the passage of the ions. This is reversible, but other things go wrong > that degrade the performance. So you want to avoid it to be sure. > > Heaters are a great way to get around it. > > > If anyone is curious, I can share this, email me your email address > Multi-Scale Characterization Studies of Aged Li-Ion Large Format > Cells for Improved Performance: An Overview > Shrikant C. Nagpure,a,* Bharat Bhushan,a,z and S. S. Babub > > > > On Thu, Jan 30, 2014 at 12:16 PM, Rick Beebe <[email protected]> wrote: > >> Blue SE or Gray CA cells? I think the CA's are a substantial improvement. >> >> Keegan at the US CALB warehouse is fairly responsive. Or if you bought >> them from one of the US resellers I'd hope they would go to bat for you. >> >> Back on topic, I am putting mine in insulated boxes with heaters in >> them. Temperature controllers will turn the heat on if the cells are >> below 40F and disable the charger until the batteries are warmed up to >> at least 45F. The design right now calls for all of that to be powered >> by shore power. I'll be monitoring the temperature to see how they fare >> while parked. >> >> --Rick >> >> On 01/28/2014 05:28 PM, Cruisin wrote: >> > If the cold isn't enough to worry when using the CALB 180ah cells, early >> > failure is substantial with the CALB cells. I have 6 customers using >> 180's >> > and all have had failures of at least one cell in the first two years. >> All >> > use a BMS and a programmed Elcon, so I know the systems are designed >> right. >> > About half died while driving, BMS alerted and they shut it down. The >> others >> > started change in resistance values making it difficult to get a >> complete >> > charge, or early discharge alarm from the BMS. One died 1 day after a >> one >> > year warranty. No replacement even though CALB was told of a possible >> > problem early on. I don't want to alarm anybody, and I am sure some >> forum >> > junkie will jump in a say he has been using the cells forever without a >> > problem. Probably some have, but my experience is that most will have a >> > early failure. Recommendation, carry sufficient tools and HV and BMS >> cables >> > to be able to isolate the cell should experience this problem. >> Otherwise, >> > you will be stuck somewhere where you don't want to be. Been there and >> done. >> > By the way, don't expect CALB to do anything, even during a so called >> > warranty period. Support and service ended when you put them in your >> donor. >> > I hope I didn't hijack this thread, just wanted to pass on what I think >> is a >> > troublesome problem. >> _______________________________________________ >> 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) >> >> > > > -- > Put this question to yourself: should I use everyone else to attain > happiness, or should I help others gain happiness? > *Dalai Lama * > > Tell me what it is you plan to do > With your one wild and precious life? > Mary Oliver, "The summer day." > > 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) 550-2430 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > Phone > (919) 631-1451 Cell > (919) 513-0418 Desk > > [email protected] > <[email protected]> > > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." 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) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... 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