We did these (at least similar) kind of things 8 years ago already. Even patented it.
How to make preemptive management decisions ? I thought the smartes way was to build database with logged cell voltage, temperature and SOC. So we did that. Most of the other cell properties can be calculated out from them. If a cells internal resistance was developing too fast the whole system capacity was reduced a bit. Then this particular cell was used in more comfortable voltage region. (LiNiMnCo and LiMn2O4). The theory of windowing the individual cell SOC areas was developed and tested. When LiFePO4 came the operational voltage area was cut out. Lower operation voltage removed a lot of the stress cell faced earlier. SOC, temperature and under-/overcharging methods still prevailed and 1st time we could see even an active method to reduce the internal resistance per cell. Also revoking capacity if needed could be done by hammering the cell to it's upper limit for a set period of time. Cells now which are nearly 9 years old and in vehicles (LiFePO4) are still manageable but these really old ones had high fail rate even when new. In one vehicle I'm following interesting episode since one cell has a positive terminal which heats in use. More than any other pole. The contact is good outside but I'm afraid it's inside the cell (we've had cells with wrong type bolts to hold foils and cell pole) I'm not planning to pull it off until next summer for battery update. I'd love to get one car over the 10 year milestone with LiFePO4's as soon as possible. -Jukka http://www.google.com/profiles/jarviju#about 2013/1/6 Lee Hart <[email protected]>: > On 1/6/2013 4:43 AM, brucedp5 wrote: >> >> >> >> http://www.equities.com/news/headline-story?dt=2013-01-01&val=878559&cat=industrial >> Flux Power develops new technology to extend life of lithium battery >> systems >> Comtex News Network >> >> Jan 01, 2013 (Datamonitor via COMTEX) -- Flux Power Holdings, Inc., a >> developer of advanced energy storage systems, has developed a new >> technology >> that can learn and adapt to the changes that occur at the cell level >> within >> a battery pack over time. > > > Maybe there is a real idea hiding in all this, but it sure looks like > marketing blather to me. Does anyone know what they are actually doing? All > I can figure out is that it's a BMS with data logging, so you can see of > some cell is chronically different from the rest. > > -- > We live in a Newtonian world of Einsteinian physics ruled by Frankenstein > logic. -- David Russell > -- > Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm > _______________________________________________ > 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) > -- http://www.google.com/profiles/jarviju#about -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130106/05d0a9ad/attachment.htm> _______________________________________________ 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)
