Aluminium cased LFP cells

[grizzzman]

I am seeing an increased number of these cells. Is this to keep them from expanding? Or more likely better cooling the last one I saw had plastic ends that put space between the cells. Perhaps a bank that ran cooling would help the pac last longer? Things that make you go hummmmm .

[native pepper]

All my lifepo4 cells are aluminium, industrial and military use them as well, for robustness and heat dissipation. Mine have never got warm, nor bulged in any way and they are normally used in cells of around 50amps.

[Busman]

I have never seen any warmth in my packs 200 ah x 12 v 800 ah x 24 v. We can charge the 24 pack at almost 200 amps and the only problem is the cables getting hot. All plastic cases, both Sinopoly and Winston.

[T1 Terry]

Aluminium cased cells have the added problem of isolation between the cell plates inside and coming into contact with the case and the case coming into contact with conductive parts of the frame work that may be at a different voltage potential to the now electrified aluminium cell case. This was the cause of the Boeing fire, some half wit screwed a bolt right through the frame work, through the aluminium cell case and into the cell plates shorting the whole battery pack to the negative terminal and causing the cells to over heat. The lithium chemistry they were using released oxygen into the cell interior if overheated and this fuelled the fire.
LFP and LYP lithium chemistry cells can not produce oxygen no matter how they are abused so they can not support a fire with oxidising agents. This means they can not explode and require air from outside the cell to combine with anything released from the cell to create the right oxygen/fuel ratio to support a flame. You may see a melted plastic case from a severe arc event, but that is not a fire or an explosion, just heat generated by that arc.
The real danger with aluminium cased cells is iron ore dust collecting on top of the cell. It doesn't take much to create a track from a terminal to the aluminium case, and arc produces enough heat to burn the cell upper case and create a carbon track, then the start of a plasma ball event is in the making ...... for more info about plasma balls it's worth reading the tale of how Plasma Boy got his name http://www.evdl.org/pages/plasmaboy.html

T1 Terry

[grizzzman]

Thanks Terry good info!