Where the foils come from
Inside each cell, the anode coating sits on copper foil and the cathode coating on aluminium foil. After discharge and shredding, these foils form flakes that can be separated from the fine black mass by sieving, air classification, magnetic and eddy current separation, and density-based methods. Casings, busbars and module hardware add further copper, aluminium and steel.
Because the metals are already in metallic form, they do not need the chemical refining that cathode metals require. Clean fractions can be sold to secondary smelters and processors, typically at a discount to exchange prices that reflects purity, form and contamination.
- Sieving separates coarse foil flakes from fine black mass
- Magnetic separation removes steel from casings and fasteners
- Eddy current separation splits aluminium from copper
- Density-based methods refine the copper and aluminium fractions
What drives the price
Purity is the main variable. Copper flake carrying residual black mass or aluminium fragments is worth less than clean copper, and aluminium contaminated with copper can be difficult to use at all. Moisture, plastic content and fine particles also attract penalties. Separation lines are therefore tuned to balance recovery against purity.
Sellers usually agree the assay method and payable percentage in advance. Where volumes are consistent, some buyers will offer indexed pricing linked to a published exchange price. Smaller or irregular lots are more likely to be sold on a negotiated spot basis.
| Factor | Effect on value | How it is controlled |
|---|---|---|
| Cross-contamination (Cu in Al) | Can sharply reduce aluminium value | Eddy current and density separation |
| Residual black mass | Reduces payable metal content | Multi-stage sieving and classification |
| Plastics and separator film | Penalty or rejection | Air classification |
| Moisture | Weight adjustment | Drying and covered storage |
Why foils matter more for LFP
Nickel-rich chemistries carry most of their value in the cathode metals. LFP cells contain no nickel or cobalt, so the cathode contributes mainly lithium, and the copper and aluminium fractions become a much larger share of what a pack is worth at the refining stage.
This is one reason second-life reuse is so important for LFP. When a module cannot be reused, clean mechanical separation of the foils is often what keeps the recycling route commercially viable, rather than the value of the black mass alone.
Field note