If a communication failure with a single cell (not even an actual fault) can cause total battery shutdown, does that lead to a lot of nuisance tripping?
Bruce Erickson Mendocino Solar Service PO Box 1252 Mendocino, CA 95460 707-937-1701 707-937-1741 fax br...@mendocinosolar.com Celebrating 20 Years in Solar! 1994-2014 On Mar 18, 2015, at 8:57 AM, Larry wrote: > Hi Jarmo, > > I agree and recognize your urgency in making us aware of the proper use and > charging of Li-ion batteries as well as the dangers of mistreating them. As > an early adopter myself, I am very cautious in my approach even to the point > of refusing to sell to some customers. Lithium battery technology is in a > state of rapid evolution. > > Not wanting to harp on the GBS brand that I sell, but one of your points goes > to prove the safety of their integrated approach. You said, "...all it takes > is one poor connection or broken temp sensor on one cell." The GBS EMS system > has cell level sensors for temperature (and other data) and each sensor board > requires constant communication with the CPU. If the EMS fails to communicate > any information with any cell, the CPU immediately shuts down both safety > solenoids, disconnecting the battery. With the non integrated systems, > failures that don't report information to the management system could lead to > disaster. > > Please keep offering us the knowledge you are gaining as I am a firm believer > that Lithium technology is a large part of the inevitable replacement the > aged lead battery. > Larry Crutcher > Starlight Solar Power Systems > > On 3/17/15 6:11 PM, jarmo.venalai...@schneider-electric.com wrote: >> Hi: >> >> I may sound like I'm a detractor against using Lion, but that's not it. >> >> What I want to bring to light is that, being as the technology is new, not >> all the issues are known and there are things to learn for all early >> adopters in the foreseeable future. >> >> From what I can gather the framework for the issues lies in that Lion >> technology is based on intercalation, that is, a reversible insertion and >> removal of Li molecules into compounds with microscopically layered >> structures. This predicates that there must be no chemical reaction in the >> battery, but rather only the shelving of the highly reactive Li ions. If >> there are any chemical reactions taking place, then in the least the battery >> performance is compromised and in the most there is a thermal event or worse >> >> There are some very robust Lion battery packs, a favorite of mine being from >> a local company from Vancouver, (well Richmond, which is a suburb of >> Vancouver). It's a small company, but they have designed, developed, built >> and successfully approved their 6 kWh Lion pack for use in large car ferries >> in Scandinavia. The ferries have stacks of these packs in the 100's, in the >> MWh size. It can be done. >> >> What I'm advocating is that its best to work with companies that have the >> time, interest and resources to work through the wrinkles, and if not, then >> carefully put in reliable and precise BMS circuitry which includes things >> like fail safe circuits for single point failures of critical sensing >> circuits, the foremost of which is cell temperature. When you're pushing >> large currents, all it takes is one poor connection or broken temp sensor on >> one cell...... >> >> Here's a link to the Lion battery pack manufacturer, Corvus, >> >> http://corvus-energy.com/ >> >> I know they do a good job, but they're not cheap,.... for now... >> >> JARMO >> >> >> Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | >> Sales Application Engineer >> Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: >> +604-505-0291 >> Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | >> Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 >> <Mail Attachment.gif> >> <Mail Attachment.gif> <Mail Attachment.gif> >> <Mail Attachment.gif> <Mail Attachment.gif> >> >> >> >> > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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