Lion & Lipo's that get gassy!

[TechNline]

I have had a few large format Lion and Lipo's that have had a gas build up under the outer plastic wrap and cause it to look puffed but they really are not. I dismantled one of the power pack batteries that looked this way even with a thicker plastic cover attached. Once I exposed the flat packs, they were not puffed at all, in fact, they look completely normal and were still at their factory thickness with no puffing at all! I also have a couple of drone batteries (Larger Drones) that have this same effect but when you glide your finger down the plastic wrap of the outer battery area that does not have a heavy plastic casing the puffed plastic is just gas trapped under this plastic and again there is no real puffing. I have had real puffed batteries before and the surface is much harder and cannot be pushed down easily.

Is this gas venting other's have seen before?

 

[thunderheart]

I've seen gassing in some of my drone lipos. As there is no vent hole the gasses have nowhere to go and i had to accurately puncture the plastic to let'em go out, then covered the small hole with a tape and used as before. After some time the gas appeared again and i had to repeat the procedure. It seems that it doesn't harm the cells. I have only 3 of those lipos which stopped holding high discharge current but all 3 are from one batch of small 150mAh cells and i think they were low quality from the start. I got them already gassed.

 

[TechNline]

I would have to agree, the cells seem to work fine with no issue. I also believe that a couple of these I received gassed too! Thanks for the input!