Safety Concerns Charging Lithium-Ion and Solid Anode lithium Batteries (Duralite)

[Frank Bis]

I have been working in the battery area for 40 + years so let me pass on my knowledge.  When the Duralites first hit the market I went on line and said "Be very careful with these solid lithium anode cells"- they can vent catch on fire etc especially after repeated cycling.  The reason for this is after several charges the lithium forms Dendrites (spikes on the surface) which punch through the separator and short out the cell.  No one paid any attention to this.  Now in the case of the Lithium-Ion these cells DO NOT LIKE TO BE OVERCHARGED.i.e. above 4.2 volts.  They will vent and catch on fire.  I use them in flat packs but each cell has a protective circuit on the cell and can be charged at constant current using a standard charger at 250 mA.  When any cell in the two cell pack reaches 4.2 V the protective circuit on the cell senses this and takes the cell off line, hence the battery of two cells off charge.  Yes these battery packs are a bit lighter and have a higher energy density (Wh/kg).  Let me pose this, Nickel-cadmium cells are a proven technology and can be fast charged safely and work.  Why not stay with they.  The Nickel-metal hydride is a good system.  However, it looses capacity on stand, and requires careful field charging to prevent it from getting too hot and venting.  Also it does not work as well at low temperatures.  My advice stay with Ni-Cd.
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