Li-ion Power pack's. From Cu & Al foil right through to 20,000mAH unit.

[Odd-Job]

Stumbled across this whilst uTubing. Well made and thorough.
From raw material right through to stress test and packaging.
Worth the 26 minutes to see current manufacturing techniques and still a large "human involvement and  hands on" job.
 Sub titles and closed caption available.


Enjoy:

Odd-job
Over