Since I am seriously considering Li-Ion at the moment, I've tried to do a bit of homework. Fortunately, I know some people that have worked in this area, although for much smaller batteries (computer laptops). Both have major concerns about safety and overcharging issues.
One writes: "Safety issues with LiION batteries are extremely important as the consequences of an accident could be spectacular and more than a bit dangerous. ... determine if the cells have any form of internal protection. So assuming they are black box devices, you must do individual cell monitoring during both the charge and discharge cycle. " The consequences of overcharging a cell may be much worse than the dead batteries that we are used to with AGM lead acid batteries. These could explode and some electrolytes may be flammable (not just caustic). So, I don't mean to discourage the brave, but much more than the usual cautions appear to be in order here. You can look at some of these companies and find that they have specialized chips for LiIon battery monitoring. I doubt that they would go to all this trouble just for LiIon (and not other chemistries) unless there are extraordinary requirements for safety or simply getting good battery life from these expensive batteries. 1. Power Smart (recently purchased by Microchip I believe) who make battery monitoring chips and have been working with the auto industry on EV solutions 2. TI bought Benchmarq who specialized battery monitoring 3. Maxim (who recently bought Dallas Semiconductor) Again, I myself am not an expert in this area. But I find them and take their advice... Gary Bruce EVangel Parmenter wrote... > If li-ion batts become affordable and available, my next > question would be > -what chargers have a charging algorithm for li-ion? > > Or what would I have to do to get my Zivan's and PFC to > charge a li-ion pack? > > If the the newer batt chemistries need sensitivity to > the batt temperature at the end of the charge, using a > bad-boy would be out (unless you want to spend a sleepless > night 'pack-sitting' the charge current). > > Most conversions will have an 'open air' batt rack design. > This could be to our advantage compared to the production > EVs that are locked up tight. > > The newer batts (li-ion, NiHM, NiZn) in our racks would > be able to dissipate heat better. And if one's charger > didn't taper on the temperature, perhaps we could > make a simple charging algorithm that tapers where we > think the temperature would be (at a certain pack > voltage). Of course, hot climates would change that, etc. > > Since we are a large group of 'put it out there' EV drivers, > there is going to be some brave soles to try this first. > So, lets think how we can do this, and be ready for when > we 'can' get our hands on these batts! > > Watt do you think?
