Rework drone lipo with generic pack

I just bought a Yuneec Q500 drones, with 2 ' dead' batteries.

They are special plastic cases with a flexible top and bottom. Inside are the lipo's ... a 3s2p 11.2V

The soft sides are under pressure and not flat anymore. Probably the reason why the batteries are dead.

My idea is to open the case with a Dremel saw blade, remove the lipo's and replace the content with generic 3s2p packs that fit into it.
Than glue the pack close again.

My question is... is there some compressed gas inside that makes it a bit spheric and not flat ?
Is there a way to safely open the case ? (not just the gloves and goggles

f.i. vent the pack before opening etc...?

advice is appreciated
Thomas

The gases inside the cells can be toxic, so I don't recommend venting it. Just remove the packs and replace them without opening the cells themselves.

If you use a dremel, you should be careful to not cut all the way thru the plastic casing. That way you don't risk cutting into a cell. (which, if they are charged, could result in a fire if the cut shorts internal layers).


FWIW, they make what's called "hardcase" LiPo; is that what your packs are? Or are they cases specifically designed for those drones, to fit into a specially-shaped receptacle?

Yes Amberwolf,

this is a hard case pack for a specific copter.



I need the case for the connector placement. I can not plug in a generic pack so deep into the bay.
I now have 3 packs like this, so I can save a lot of money refurbishing them.

I thought the gas is oxygen ? Is it more than that ?
I will cut carefully

It depends. Oxygen and carbon compounds are part of the decomposition gases, but once there's gas in there for stuff to evaporate into, the other compounds in the electrolyte can vaporize, and then they come out, too. That's what that "sweet" smell is when you puncture one (the "safe" stuff like oxygen doesn't have a smell).

So, I will start cutting the case with a Dremel. Starting next to the connector / front size. There will be no battery in there. Than I will try to force it open by pulling the two halves. If no success I will cut a circumference.

First, I decharged the pack, just to be sure, by wiring a car bulb over the terminals



Next, I cut it open with the Dremel, starting at the less risky and.


(Mind the sand bucket.....

The inner battery showed to be also part of the outer casing. Did not see that coming, but it explains why the outer surface was ' blown-up'.



Now, I have a nice casing for a generic LIpo. They are under way.




will be continued.
Thomas