Condition and testing terms
State of health describes remaining capacity as a percentage of rated capacity, although some reports blend in resistance or other indicators without saying so. State of charge is simply how full the battery is at a given moment and says nothing about its condition. Internal resistance, measured with DC current pulses or inferred from impedance spectroscopy, indicates how much a cell heats and how far its voltage sags under load, which matters greatly for second-life suitability.
Grading is the process of assigning a module to a band based on test results. On our benches Grade A means at least 85% retained capacity, Grade B covers 75% to 85%, Grade C covers 65% to 75%, and anything lower or defective is routed to refining. Other organisations use different thresholds, so asking which definition a counterparty uses before comparing prices avoids disputes about value once modules have already changed hands.
| Term | Meaning | Common confusion |
|---|---|---|
| SOH | Remaining capacity vs rated capacity | Confused with state of charge |
| SOC | Current charge level | Mistaken for battery condition |
| DCIR | Resistance from a DC current pulse | Not directly comparable with AC impedance |
| EIS | Impedance measured across a frequency sweep | Assumed to replace capacity testing |
Process and materials terms
Black mass is the powder left after cells are shredded and casings, foils and plastics are separated out. It contains cathode and anode active material and is traded on its assayed metal content. Mechanical pretreatment covers discharge, dismantling, shredding and separation, while thermal pretreatment removes electrolyte and binder either before or after shredding. Both affect the composition of the black mass and therefore how a refinery will price and process it.
Hydrometallurgy dissolves metals in acid and recovers them as individual salts through impurity removal, solvent extraction and crystallisation. Pyrometallurgy smelts material at high temperature to produce a metal alloy and a slag, with some elements lost to the slag. Precursor cathode active material, usually shortened to pCAM, is the mixed hydroxide or similar compound that cathode makers convert into finished cathode active material, known as CAM, for new cells.
- Black mass: shredded active material, priced on assay
- Leaching: dissolving metals from black mass in acid
- Solvent extraction: separating dissolved metals into individual streams
- pCAM and CAM: precursor and finished cathode active material
Regulatory and commercial terms
Under the EU Battery Regulation, recycling efficiency describes the share of a battery's mass that a process recycles, while material recovery refers to specific elements such as lithium, cobalt, nickel and copper recovered for reuse. Extended producer responsibility, or EPR, is the principle that producers pay for and organise the end-of-life management of the products they place on the market, whether directly or through a producer responsibility organisation.
Payables are the percentage of contained metal value that a black mass buyer agrees to pay, usually linked to a published price index. A recovery certificate records the quantity processed and the outcomes achieved, while an EPR certificate in India is generated on the central portal against verified recycling. The battery passport is the EU's digital record that relevant batteries must carry from February 2027, covering composition, origin and end-of-life information.