There’s no metallic lithium in rechargeable li-ion cells to react with water. Only non-rechargeable li-metal batteries have metallic lithium in them.
You’re right about the fumes…incredibly toxic.
3 Likes
There’s no metallic lithium to react with water but, yea, you do need enough water to quickly bring the temperature of the cells down below the thermal runaway threshold. That stops the exothermic reactions and you can then just put out whatever fire remains from the electrolyte, plastic layers inside, or the wrap.
8 Likes
We have just been schooled 
Thank you Mooch 
4 Likes
Appreciate your input as always; thanks Mooch! 
2 Likes
Most advise says don’t mix cells. Personally for the sake of saving 48cells 150 ish on a board that costs over a 1500 is the 10% worth the risk?
What about the fumes when they aren’t burning? I hate that lithium smell, but encounter it all the time when opening up evolve batteries.
1 Like
There shouldn’t be any electrolyte (battery liquid) fumes if the cell cans haven’t been opened.
Hmm…if the cells get hot though then the wraps and ink on the wrap can off-gas and smell pretty bad. That has only happened when they get MUCH too hot for regular use.
Various tapes, heat shrink, adhesives, etc., can all stink up an sealed enclosure pretty badly though too. That smell might not be the cells.
1 Like
The cells in the evolve packs are pouch cells. Quite often they are puffy.
The smell is undeniably lithium tho. My question however, is are those ‘raw’ lithium fumes toxic? Or only when the lithium is cooking? 
1 Like
Well the whole thing is a 600$ used parts from ebay Mountainboard for a friend of mine who has no money but wants to ride with us. We had some old packs laying around and thought it would be good enough so he can save money (:
For my own boards I would build a new battery for sure.
2 Likes
Ahh…pouch cell? Yup, verrrrry delicate.
If they puff a little for a short period of time and then go back down that is bad but they might not have been damaged too much. If the cells stay puffed they are badly damaged and should never be charged or used again. The gas that causes puffing is from the liquid (electrolyte) breaking down from the heat and that is very not good.
AFAIK, lithium and and the lithium compounds used in cells are odorless. The lithium in a rechargeable li-ion cell is bound up in a metal-oxide (“rust”) powder and a salt. There is no odor for those. The liquid electrolyte however is made up of organic solvents and always smells and is always toxic. Never breathe the fumes of a cell that is exposed, whether it’s a good cell that has just opened up or a cell on fire. There are some stunningly nasty things in the smoke of a burning Li-ion cell. The powder residue from a fire is toxic too and contains cobalt, considered by many to be a carcinogen.
If you can smell that liquid that means the cell has opened up and is ruined. It should not be charged or used. However, the pouch materials and other things can often smell pretty bad too. I’ve never had a new LiPo cell that didn’t reek.
5 Likes
I’ve extracted metallic lithium foil from Energizer lithium batteries for chemistry experiments before. The lithium itself is odorless, what you’re smelling is the organic electrolyte. And yeah, it’s pretty nasty stuff.
Pouch cells are ever so slightly permeable (at least compared to steel cans) so yeah, you often get a whif of electrolyte that has just houdini’d its way out of the pouches.
5 Likes
Excellent, thanks dudes.
note to self: stop huffing battery fumes
8 Likes
Pouch cells are vacuum sealed. If they were at all permeable they would dry out as the electrolyte wafted out. This would ruin the cell.
What we smell might be remnants of something along the edge when the “gas bag” was cut off from the side after the cell was formed (first charging) or just the smell of the plastic coated aluminum itself.
The electrolyte has always smelled completely different to me than anything on the outside of a LiPo.
1 Like
Anyone who has ever seen a balloon slowly deflate in the hours and days after a party knows the level of permeability I’m talking about. (And that’s an extreme case, because helium is such a tiny atom that it squeaks its way out of just about anywhere.)
I’ve got a leak detector that I’ve been repairing over these past few weeks, that is sensitive enough to detect a helium leak of 1.0x10-10 ml per minute. A leak several orders of magnitude larger wouldn’t result in sufficient electrolyte loss to kill a cell over its lifetime, but would be easily detectable.
I’ve taken apart/punctured enough lithium ion cells to know the smell of the electrolyte. I’ve definitely smelled that smell when opening up a pack, before having poked any holes in anything.
3 Likes
You’re talking about leaks out the side though (especially if the cells ever puffed), where it’s heat sealed. Nothing is permeating through the plastic/aluminum pouch material IMO. I think we had different thoughts regarding where the cell could be permeable. No worries though!
1 Like
Same. And nearly every evolve pack I’ve opened, absolutely reeks of it
3 Likes
I’ve even noticed a hint in ipods and smartphones. Much more subtle of course, due to the drastically smaller size of the battery.
2 Likes
Deal for the Aussie builders out there, Techaroundyou have quite good prices on Apexium 18650 2600mAh 35A cells at $4.99 AUD per/cell.
Techaroundyou - Apexium 18650 2600mAh 35A
Yeah and wtf are Apexium cells, shit sounds suss as fuck. Fair point.
Performance-wise they are slightly better than the well-known Sony VCT5 and near-identical to the VTC5A.
I’ve purchased 60 of them for use in an eMTB, according to HJK they can handle even 30A whilst tracking fairly well, in a 5p config that should comfortably net you 120A or more battery current. Fuck yeaah.
Anyone ever heard of these cells before out of interest? Never seen them anywhere until I purchased them on sale today after perusing the HJK charts.
1 Like
I think you are gonna be taking your life into your own hands if you plan to push those cells to their ‘limits’
But definitely curious to see how they work out for you 
2 Likes
lol yeah nek minute my feet get melted off when these cells hit thermal runaway at 30A and explode 
noice 