I was reading somewhere that most laptop batteries use 18650 lithium-ion cells internally, and it hit me. I had a laptop sitting in a drawer that died shortly after I bought a brand new battery for it. The battery was about 4 years old, so I took it out and pried it apart. Inside the laptop battery case, as expected, were 12 green 18650 batteries. They are most likely Panasonic. Since the laptop died shortly after buying the battery, each of these cells probably only saw a couple charge cycles-they are almost new!
A quick reading on the multimeter showed that most of the cells were reading at least 3.5 volts. Not bad for sitting in a drawer for several years. The laptop manufacturers must subsidize these cells, because I have 12 cells that cost $10 each, and I know that the laptop battery didn’t cost anywhere near that.
DISCLAIMER: Li-ion cells can be dangerous if handled wrong. Don’t be a dumbass. I even sparked a couple of my cells because I was so impatient cutting them apart. I’m surprised natural selection hasn’t claimed me already. If you have any doubts about what you are doing, stop, and visit the Battery University.
What I intend to do with these cells it to put them into a power pack as a backup/emergency charging system for my electronics. A good power pack costs close to 100 bucks and probably has cheaper cells inside than what I am putting in.
The only real downside is that they are welded together in the pack, and breaking them up leaves these little sharp burrs. I’ve seen it mentioned where some folks are using a Dremel tool to smooth them out, but I’ll probably just use a small file.
Update: As pointed out by Chris below in the comments, these are definitely Sony 2400 mAh cells.
|I had to cut the little plastic bars holding them in|
|Partially separated. Be careful cutting them out!|
|Fully separated, but each one has some burrs on it. Be careful not to cut yourself!|