> From: Mike Nickerson via EV <[email protected]> > > I think the problem happens when the constant current charger doesn't stop > when the cells are full. The cell can't store the energy, but it has to go > somewhere. They are sealed, so it can't just bubble off water like lead-acid > cells do. The energy breaks down the electrolyte and builds pressure until > the cell finally blows. > > Once full, I don't think it matters how large or small the current is. It > will cause damage and it is additive.
I'm not saying you're wrong. But as an electrical engineer, no one has explained it to me in a way I can understand yet. No working cell should see more than a few hundred milliwatts in the scenario cited. This is roughly the energy dissipated by your left ear. (Well, maybe you left hand, unless you're exerting yourself.) The energy dissipation alone is not enough to cause the damage shown. As Cor mentioned, are these cells actually sealed? With no safety vent? I guess I can imagine an explosion in such a case, but still, basic thermodynamics don't support that. Pressure from disassociation should lead to re-combination elsewhere, due to the limits of the power supplied. Cells that size should be able to dissipate low tens of watts safely. Energy out must not exceed energy in. :::: Being influenceable is the key to influencing others. -- Stephen R. Covey :::: Jan Steinman, EcoReality Co-op :::: _______________________________________________ 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)
