Thermal behaviour of NMC 811 (2170)
High-nickel NMC cathodes release oxygen as they decompose, so once runaway starts it is fast and energetic. Cylindrical 2170 cells vent through a designed rupture point, which helps, but cell-to-cell propagation inside a tightly packed module is the main hazard.
Whatever the chemistry, heat, mechanical damage and overcharge are the three triggers to control. Storage areas need detection, separation and a clear response plan.
Packaging and transport checklist
Cylindrical modules are dense and often liquid-cooled: drain and cap coolant lines, check for coolant ingress, and keep modules below 30% state of charge for storage and transport.
- State of charge below 30%, recorded per serial
- Terminals taped or capped; service disconnect removed
- UN-approved packaging with non-conductive cushioning
- Class 9 marks, UN number and emergency contact on every package
- Damage status declared on the manifest before pickup
Disassembly considerations
Cells are usually glued into carriers with wire-bonded interconnects, so module harvesting is realistic but individual cell recovery is slow. Most value comes from grading whole modules.
Every disassembly step starts with verified isolation and insulated tooling. If a module cannot be opened safely, it is discharged and routed to shredding instead.
Field note