Ask two battery recyclers how to handle a dead pack and you may get two incompatible answers. One says: recover the metals — break the cells down to cobalt, nickel and lithium salts you can sell back into the supply chain. The other says: that is wasteful — restore the cathode material directly, skipping the costly trip back to raw metal. The 2022 patent record shows both philosophies funded and filing.On the recovery side, Northvolt's US11509000B2 claims a process for recovering cathode materials by removing aluminum and iron — a hydrometallurgical approach, dissolving and purifying. Worcester Polytechnic's US11502345B2 claims a method and apparatus for recycling that recovers metals. These are the descendants of mining-style metallurgy applied to batteries.On the direct side, Hulico's US11394062B2 claims relithiation in oxidizing conditions — putting lithium back into a depleted cathode so the cathode itself can be reused. Storagenergy's US11492267B2 claims a flame-assisted method to directly recycle and even upcycle spent cathode. The bet here is that rebuilding the cathode is cheaper than melting it down and synthesizing a new one.Why the split matters to economics: smelting and full hydrometallurgy are energy-hungry and capital-intensive, but they handle messy, mixed feedstock. Direct recycling is far cheaper in energy if it works, but it demands clean, sorted, single-chemistry feedstock — which the real waste stream rarely provides. The method you pick is really a bet on how clean your feedstock will be.Northvolt's presence on this list is worth a flag for filing-watchers: a vertically integrated cell maker patenting recovery chemistry signals it wants recycling inside its own supply loop, not outsourced. That is the off-take story — recycled metal as a captive, price-hedged input rather than a commodity bought on the open market.The shared CPC code H01M 10/54 marks all of these as battery-reclamation patents, but the divergent secondary codes — C22B metallurgy classes for the recovery camp, H01M cathode classes for the direct camp — are where the philosophy shows. Read the secondary codes and you can tell which bet a recycler is making before you read a word of the claims.
“A process for removal of aluminium and iron in the recycling of rechargeable batteries comprising providing a leachate from black mass, adding phosphoric acid (H3PO4) to said leachate and adjusting the pH to form iron phosphate (FePO4) and aluminium phosphate (AlPO4), precipitating and removing the…”— U.S. Patent No. 11,509,000 source