What Is at Issue: Recycling That Regenerates Instead of Dissolving — Where Do the Rights Sit?
Direct-recycling patents are moving toward claiming “which units the process is cut into and at what temperature it is run,” rather than “how much is recovered.” This article compares two patent lines from U.S.-based Li Industries with an earlier lithium-reintroduction patent to show how technologies aiming to replace hydrometallurgy appear in the claims.
Start with the industry context. As EV adoption expands and the handling of spent batteries comes into focus, technology that recovers nickel, cobalt and lithium from “black mass” (the electrode powder left after shredding spent batteries) is drawing attention. In Korea, SK Ecoplant said on September 10, 2023 that it would invest about KRW 330 billion to build a secondary-battery recycling plant in Gangdong-myeon, Gyeongju, North Gyeongsang Province, with completion targeted for 2028, according to reports. On the regulatory side, when the Council of the EU adopted the batteries regulation on July 10, 2023, it set minimum recycled-content levels (16% for cobalt, 85% for lead, 6% for lithium and 6% for nickel) and lithium-recovery targets for waste batteries (50% by the end of 2027 and 80% by the end of 2031).
The source of tension is the limitation of the current mainstream process. Hydrometallurgy dissolves the active material in acid and returns it to elements, so the crystal structure is lost and synthesis has to be repeated from scratch to use it as cathode material again. Direct-recycling patents aimed at bypassing this are increasing. This article answers three questions: how does direct recycling differ from hydrometallurgy, what do the representative patents claim, and which elements should planning and IP staff check first when designing a recycling process?
Basic Principle: Instead of Melting the Castle and Recasting It, Slot In Only the Missing Bricks
Cathode material can be likened to a “Lego castle” in which lithium, nickel, cobalt and other elements are stacked in a fixed crystal structure. In a long-used battery, most of the castle’s frame remains, but some lithium bricks are missing and the surface is scratched. Hydrometallurgy melts the whole castle back into brick raw material and then molds a new castle. It can recover elements at high purity, but it consumes a lot of energy and chemicals.
Source: concept diagram reconstructed by the editorial team from the original article and the claims of US8846225B2 and US12266772B2
Direct recycling is an approach that keeps the castle’s frame as intact as possible while slotting the missing lithium bricks back in and repairing the surface. The process gets shorter, but in exchange the problem of chemical non-uniformity in the spent batteries used as feedstock has to be solved. Spent batteries from different manufacturers and usage histories vary in degradation and composition, so to preserve the frame, the incoming feedstock must first be made uniform.
An early example in this direction is US8846225B2 (title: “Reintroduction of lithium into recycled battery materials”; owner Steven E. Sloop; priority date February 22, 2008; grant date September 30, 2014). Claim 1 is a method of placing lithium-deficient cathode material harvested from a recycling stream into an aqueous lithium-ion solution in a pressure vessel, hydrothermally treating it at 100–300°C to diffuse lithium into the crystal lattice, and then isolating and sintering it to obtain recycled cathode material.
Comparison: Hydrometallurgy vs. Direct Recycling, and Processing Conditions by Patent
| Item | Hydrometallurgy | Direct recycling |
|---|---|---|
| What is processed | Black mass dissolved in acid | Cathode material processed with its crystal structure retained |
| Recovered output | Metal ions and compounds (element level) | Regenerated cathode material (active-material level) |
| Additional steps before reuse | Precursor and cathode resynthesis required | Lithium replenishment and surface-defect repair |
| Sensitivity to feedstock variation | Relatively low (broken down to elements) | High (composition and degradation variation directly affect quality) |
| Representative processing temperature (as stated in patents) | Outside the scope verified in this article | Hydrothermal lithium reintroduction at 100–300°C (US8846225B2) |
Source: compiled by the editorial team from the original article’s explanation and the claims of US8846225B2
What this table says: The two approaches diverge on the unit of recovery (element vs. active material). Direct recycling reduces resynthesis steps but takes on the burden of absorbing feedstock variation within the process.
| Patent | Owner | Priority date | Grant date | Status / expected expiry | Key conditions in claim 1 |
|---|---|---|---|---|---|
| US8846225B2 | Steven E. Sloop | 2008-02-22 | 2014-09-30 | Active / 2030-09-13 | Lithium reintroduction by hydrothermal treatment at 100–300°C, then sintering |
| US11631909B2 | Li Industries Inc | 2018-11-28 | 2023-04-18 | Active / 2040-04-28 | Processing into core sections → placing in solvent → substantially homogeneous distribution of active elements via ionic conductive medium |
| US12266772B2 | Li Industries Inc | 2022-05-11 | 2025-04-01 | Active / 2043-05-10 | First heat treatment at about 100–700°C (decomposing at least 80 wt% of binder) → separation from current collector → second heat treatment at about 400–1,200°C (decomposing at least 90 wt% of remaining binder) |
| US12431553B2 | Li Industries Inc | 2022-05-11 | 2025-09-30 | Active / 2043-05-10 | Same two-stage heat-treatment temperature ranges and binder-decomposition ratios as US12266772B2 |
Source: compiled by the editorial team from Google Patents bibliographic data and claims (US8846225B2, US11631909B2, US12266772B2, US12431553B2)
What this table says: The patent with a 2018 priority date claims “which units the cell is cut into and where they are placed,” while the patents with a 2022 priority date claim “at what temperature and how much binder is decomposed.” Even within the same applicant, the focus of the rights has shifted from process structure to heat-treatment parameters.
Patent Perspective: From Core Sections to Two-Stage Heat Treatment
Gist of the US11631909B2 claims (restated): The title is “Methods and systems for scalable direct recycling of batteries”; the applicant is Li Industries Inc; the priority date is November 28, 2018, the filing date November 26, 2019 and the grant date April 18, 2023. Claim 1 consists of the steps of ① processing one or more batteries into a plurality of core sections, each containing an anode section, a cathode section, a separator section and electrolyte; ② placing the core sections into a solvent to produce a cathode-materials mixture; and ③ achieving a substantially homogeneous distribution of active elements within the cathode materials through an ionic conductive medium formed by the solvent and the electrolyte.
Source: reconstructed by the editorial team from the claims of US11631909B2
Two corrections to the original: First, the original described US8,846,225 as “a conventional technique that adds lithium back in only after hydrometallurgical processing.” Claim 1 of this patent is a method of reintroducing lithium into harvested cathode material by hydrothermal treatment, and it does not presuppose a hydrometallurgical process. The US11631909B2 specification mentions this patent as a reference on hydrometallurgical recycling. Second, the original treated US12266772B2 and US12431553B2 as follow-on patents in the same family and wrote that they claim temperature, time and atmosphere. According to Google Patents, the two patents are a separate line based on a May 11, 2022 priority, and no continuation relationship with US11631909B2 is shown. What claim 1 recites is temperature ranges and binder-decomposition ratios; processing time and atmosphere are addressed in the embodiments of the specification, not in claim 1.
Insight: the same applicant’s two lines attack the uniformity problem at different points. The 2018 line claims “liquid-phase homogenization”: placing core sections containing electrolyte into a solvent to form an ionic conductive medium and spreading active elements evenly within it. The 2022 line claims “thermal purification”: removing binder step by step through two heat treatments. If the former averages out feedstock variation by mixing, the latter removes impurities by burning them off. Because the fundamental challenge of direct recycling — non-uniform feedstock — has been split into two branches and patented, a competitor will find it hard to complete an FTO by designing around only one line.
Design-around points: The core of US11631909B2 is placing “core sections containing electrolyte” into a “solvent.” A process that first discharges and dismantles the cell, removes the electrolyte and processes only the separated electrodes may lack this element. US12266772B2 and US12431553B2 include limitations that the first heat treatment decomposes at least 80 wt% of the binder and the second decomposes at least 90 wt% of the remaining binder. A process that removes binder by solvent dissolution rather than heat treatment could keep its distance from the first-heat-treatment element.
Design-around scenario (counterargument): However, the temperature ranges in the two heat-treatment claims are broad — “about 100–700°C” and “about 400–1,200°C” — and qualified by “about,” so they may overlap with ordinary calcination processes. There is also room to argue that dissolving most of the binder with a solvent and then removing the remainder by high-temperature calcination satisfies the second-heat-treatment element. Conversely, from the patentee’s side, such broad temperature ranges may overlap with existing heat-treatment literature and become the subject of validity disputes. Ultimately, both the possibility of design-around and the stability of the rights can only be judged by comparing individual process conditions and prior-art documents one to one.
Limits and Outlook
Direct recycling runs into the practical barrier that every spent battery has its own degree of degradation and chemical composition. The evolution of patent literature toward specifying heat-treatment conditions numerically can be read as an attempt to solve this uniformity problem through process design. As this intersects with the EU regulation’s move to institutionalize recycled-content ratios, patents related to “guaranteeing the performance of regenerated material,” rather than the recovery rate itself, are likely to increase.
There is also a counter-scenario. The EU regulation’s minimum recycled-content levels are expressed on an element basis — cobalt, lithium, nickel and so on. Element-based rules can be met just as well by metals recovered through hydrometallurgy, so the regulation does not specifically favor direct recycling. If large-scale hydrometallurgical capacity becomes established first, direct recycling may remain in niches with uniform feedstock, such as specific cathode compositions or process scrap.
The strategic alternative is to design the two approaches not as rivals but as branches by feedstock. If the flow is split so that process scrap of known composition goes to direct recycling and end-of-life batteries with mixed histories go to hydrometallurgy, the scope of FTO review for direct-recycling patents can also be limited to that branch.
Practical action: Staff planning a recycling process should build a table comparing their process’s binder-removal step (whether heat treatment is used, temperature bands, and how the decomposition ratio is measured) against the numerical limitations in claim 1 of US12266772B2 and US12431553B2, and update it whenever process conditions change.
Items requiring verification
- The processing method (hydrometallurgy or direct recycling) and capacity of SK Ecoplant’s Gyeongju plant
- The start date for the EU batteries regulation’s minimum recycled-content levels (Article 8 of the regulation text needs checking)
- Foreign family members and continuation filings of US11631909B2
- Whether processing time and atmosphere conditions are included in dependent claims of the US12266772B2 line
Sources
- Google Patents, US11631909B2 “Methods and systems for scalable direct recycling of batteries” bibliographic data, claims and specification
- Google Patents, US12266772B2, US12431553B2 “Methods and systems for scalable direct recycling of battery waste” bibliographic data and claims
- Google Patents, US8846225B2 “Reintroduction of lithium into recycled battery materials” bibliographic data and claims
- Council of the EU, “Council adopts new regulation on batteries and waste batteries,” 2023-07-10
- Hankook Ilbo, “SK Ecoplant to build secondary-battery recycling plant in Gyeongju,” 2023-09-10
Related Reading — All-Solid-State Battery Interfacial-Resistance Patents — Why Does Resistance Rise When Solids Meet? · Sodium-Ion Battery Patents Are Surging — Who Really Wins the Low-Cost Battery Era? · 4680 Cell Thermal-Management Structure Patents — The Next Battleground After Tabless
Pingback: All-Solid-State Battery Interfacial-Resistance Patents — Why Does Resistance Rise When Solids Meet? - Frontiercell