Lithium Ion batteries, how dangerous are these?

I have 60 free lithium ion batteries. They all test, 3.8v, 3.9v, 4.0v, 4.1v. I ordered 2 chargers that will charge 1 battery each. I ordered another charger that will charge 2 batteries at a time. Digital read out that shows the original battery voltage, it also shows voltage as battery charges. 1 battery is all my LED security lights need to operate. I also ordered a battery tester to learn how good the battery is under load.

After watching YouTube videos of lithium ion battery fires & explosions I wonder how safe these batteries are? Damaged battery goes off like a rocket engine and nothing will put them out. Video showed batteries in a hot vehicle explode.

My work shop gets 150°F with the door open after lunch. No AC. Forecast today 95°F again. Its been 100° for 6 weeks.

Got a working ABC class fire extinguisher on stand by?

Soldering wires to any battery is a bad idea. If you overheat it, you can damage some of the internals, making it more likely to malfunction.
Use a battery holder, or use batteries that have the tabs pre-connected on them, you can solder to the tabs...

sagor1 said:

Soldering wires to any battery is a bad idea. If you overheat it, you can damage some of the internals, making it more likely to malfunction.
Use a battery holder, or use batteries that have the tabs pre-connected on them, you can solder to the tabs...

Click to expand...

Batteries all have pre connected tabs I can solder to.

gary350 said:

Batteries all have pre connected tabs I can solder to.

Click to expand...

Good.
The pink/red batteries in your picture did not seem to have connected tabs on them (unless they are folded over somehow), hence my comment.

gary350 said:

After watching YouTube videos of lithium ion battery fires & explosions I wonder how safe these batteries are?

Click to expand...

Don't overcharge them & don't over-discharge them (voltage or current, in either case).
Don't physically damage them.

Get rid of any that read very low, zero or less than a couple of volts.
Any that are less than 3V, try charging at a very low current - like using a 1K resistor from 5V so only a couple of milliamps, for a few hours or even a day or two, and see if they come back up to 3V or at least are showing a steady voltage increase.
Discard them if not.

Do not, ever, use them for things that don't have a reliable low voltage cutoff somewhere around 3.3V - so no simple LED flashers!!!!

Potential danger? I worked that out a few days ago for a video I'm doing for my youtube channel:
(Noting in that, that the calculation is for really high quality cells).

The energy release may not be as fast, but the potential for damage to property or life is there.

gary350 said:

Batteries all have pre connected tabs I can solder to.

Click to expand...

The upright ones definitely appear to have had the welded tags removed - the positive ends look like bare cell positives terminals. The remains of the spot welds are clearly visible.

When separating cells from pre-built packs, cut any welded link strips in the middle and fold the ends back to over the centre of the cell end (especially the positive, try and keep it within the visible "button" of the cell itself).

The best advice I have seen when experimenting with LiIon batteries:

● Work outside in a non-flammable area

● Have a fire safe close at hand.

If a battery starts to cook off, drop it in the fire safe, lock the door and RUN.

Alternatively, a metal bucket full of dry sand may be used. If a battery starts to cook off, bury it in the bucket of sand and leave it be.

No fire extinguisher will put out a lithium battery fire.