7.3 Lithium

I declare: solidlikelyshaky

1. Explain thermal runaway in a lithium cell, what triggers it (short circuit, overcharge, puncture, heat) and why it doesn’t stop.
2. Handle bare cells without short circuits: insulated tools, no rings, nickel strips never bare on the bench.
3. Charge and store: never unattended, on a non-combustible surface, at half charge for storage, never below freezing.
4. Say what to do with a swollen or hot cell and how to dispose of it (recycling in N.B.), and what a lithium fire needs (plenty of water, sand; not an ordinary extinguisher).
5. Explain the transport rules for a lithium pack (mail, air) and why.
6. Explain the built-in protections of a retail cell (PTC, CID, vent) and why bare pack cells don’t all have them.
7. Diagnosis: a pack that heated up for no apparent reason, internal short in a cell, failed BMS or charging in the cold; how to know without reopening it hot.