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GM Battery
neptune:
well,I'm glad you people didn't make it confusing!Also I was under the impression that li-ion (li-mn)as used in tool packs and refered to as konion,were 3.6 v.maybe some one who does know the specs should post with the manufacturer's test results.Oh yeah,and erase these "expert" statements.My batts are made from makita 18v,5s2p tool pks limn konion ( sony).There are hundreds of differ
ent lithium battery chemistries,if not thousands.K.I.S.S.
GM Brazil:
I thought they were of LiFePO4, since the code is LFP! GM says, in the comparative table at the end of the web page on batteries, the life cycle of batteries Mn is unacceptable!
The Mn batteries are dangerous about explosions and etc?
I thought I had bought a LiFePO4 ....
Bikemad:
--- Quote from: GM Brazil on January 13, 2010, 10:38:10 PM ---The Mn batteries are dangerous about explosions and etc?
--- End quote ---
The Lithium Manganese batteries that GM use are not dangerous like Lithium Polymer:
--- Quote ---The Lithium Manganese battery chemistry is different to that used in standard Lithium ion and Lithium polymer batteries, which usually come with a Cobalt cathode and are prone to thermal runaway - ie explosion and fire.
Manganese, unlike Cobalt, is a safe and more environmentally benign cathode material.
If you're buying a Lithium powered electric bike from someone else, ask the retailer about battery safety and life expectancy - if they cannot guarantee that they use Lithium Manganese and don't understand the importance of a reliable, well-engineered battery management system, our advice is simple: don't buy!
--- End quote ---
--- Quote from: Golden Motor ---Lithium ion rechargeable battery, 26650 size, LiPF6 electrolyte, Manganese Spinel structure cathode.
--- End quote ---
Hopefully that's put your mind at ease.
Alan
GM Brazil:
Thanks BikeMad!
I thought I had bought a LiFePO4.... I found the place that created all the confusion, on the DIY page there is "lithium iron" under one of the photos, I think they mean to write "ion" ;)
Mine is almost here, the shipment company called me to ask some information about the address. So the pie with the LiMn battery should be here soon!
Leslie:
The GM batteries are still priced fairly IMO.
Here is some good reading from ther site below.
http://www.candlepowerforums.com/vb/showthread.php?t=211891
--- Quote ---LiMn li-ion cells are a new breed of safe chemistry cell, available commercially as loose cells only in 16340 (RCR123) size from AW, but coming soon in 18650 size, with 18650 and 26670 sizes already available to li-ion powered tool manufactures. (they can be torn down to get at the cells, which many of us have done) This cell chemistry is similar to LiCo in that it shares the same charging requirements and has the same nominal voltage rating of 3.7V. The similarities end there. I would consider these cells to be a notch safer than the LiCo cells based purely on chemistry, as they can not generate their own oxygen during an out-gassing and therefor are incapable of accelerating their own burn in an oxygen deprived environment. (regular lithium CR123s and LiCo chemistry both share this trait of fueling their own fire when something does go wrong, with the potential to become a full blown metal fire). LiMn chemistry cells are good for responsible adult users who know to shut the light off before the battery is over-discharged, as over-discharge will reduce the cycle life of these cells. While this cell chemistry is safer, I would not consider it to be an ideal option for use in a flashlight that is given to a child to play with for fear that the cells may be ruined if the flashlight is left "on" and unattended to completely deplete the cells. Energy density on LiMn cells is about 30% less than LiCo cells, however, in the smaller RCR123 size, since they do not have a PCB consuming a large piece of real-estate (as compared with the overall size of the cell) these cells actually come surprisingly closer to the capacity of the protected RCR123 LiCo cells than do the larger LiMn cells when compared against equivalent size LiCo cells.
LiFeP04 li-ion cells are also a relatively new breed of safe chemistry cell. Commercially they are popping up in many sizes, with RCR123s being the most popular. These are a very safe cell, but suffer from the problem of not being nearly as tolerant to over-discharge as a NIMH cell would be. Since these are "safe chemistry" cells, they, Like LiMn cells, are not sold with PCB circuits to prevent over-discharge. They really do require the user to actively participate in the prevention of over-discharge to prolong the cycle life of the cells, just like the LiMn cells. I would be perfectly comfortable handing a child a light with these cells in it as far as safety is concerned, but the issue of whether or not the cells would survive the attempts to keep the light on long after the battery has gone dead is another issue all-together. As for energy density, combine these cells lower nominal voltage rating (3.2V) with roughly HALF the AH storage as compared with LiCo cells, and these have only about 1/3rd (give or take) the energy density as compared with CR123 primaries or LiCo cells.
--- End quote ---
It seems that the LiMn cells have slightly higher energy density than LiFePo4 and do not evolve o2 from the oxide chemistry of the Cobalt and others, they do not feed their own destruction.
Good luck with the new pack.
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