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Patent Trends: Technology Innovations in Battery Recycling

Abhirabh Basu, Analyst
May 11, 2021

With more than 400 GWh of lead-acid batteries and more than 250 GWh of Li-ion batteries (LiB) deployed annually, the next decade will see a massive rollout of battery recycling infrastructure needed to meet nearly 1 million tons of batteries approaching their end of life. However, due to the variety of batteries and LiB battery chemistry feeds used across BEVs and commercial electronics, today, standardization of industrial recycling processes is difficult and economically challenging to scale up.

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Lux expects that by 2030, battery recycling supply will rapidly accelerate to secure materials battery chemicals and materials. Innovation in battery recycling technology can drive down the cost of recycling and lead to more sustainable practices in battery waste management. In this insight, we analyze patent application trends across three different main battery recycling technologies: mechanical, pyrometallurgical (pyro), and hydrometallurgical (hydro) recycling processes. 

Over the past 10 to 15 years, there has been a consistent growth in mechanical and hydrometallurgical methods of recycling batteries, with mechanical recycling methods like direct recycling getting more interest in recent years. While not evident in the graphic below, pyrometallurgical processes are the most widespread method, as they use heat to break down a battery to recycle some portion of the materials. Pyro is effectively a smelting process and not easily patentable. We expect its adoption to be low in the future due to its high energy demand, associated carbon emissions, and more importantly, its low recovery rates (<60%).

Lux Research - Battery Recycling Patent Activity

MECHANICAL RECYCLING

Nearly all battery recycling processes include a mechanical step (typically stripping, dismantling, or shredding) creating a "black mass" of precious metals and cathode active materials. Mechanical processing involves separating plastics, electrolytes, adhesives, anodes (graphite/carbon), and aluminum as well as copper from current collectors. The metallic/mineral components are crushed into a fine powder to sieve out the product. While the process can recover cathode materials directly, it generally needs sorting batteries upstream to keep the electrode chemistry uniform. This is also referred to as "Direct Recycling," a form of mechanical recycling that uses methods like gravity separation to retain the cathodes' crystal morphology and recover materials without causing chemical changes. OnTo Technology is one of the few companies offering direct recycling today. Lux anticipates the greatest opportunity for direct recycling from manufacturing waste, where cell manufacturers can control the input waste stream in order to recycle the same cathode chemistry.

Outside of direct recycling, other innovations for mechanical recycling will focus on automating this process to reduce labor and time, but the biggest differentiator we expect to see is in the method for discharge, cell inactivation, and then dismantling under safe conditions to avoid explosion or bursting.

A good example of this can be seen in Battery Resourcers' process, which uses an inert environment to discharge batteries before crushing them. While this process can be expensive, as it requires creating an inert environment, the company claims that at scale, it becomes more economical. Li-Cycle, on the other hand, claims to have a more economical process, immersing the battery in an aqueous solvent to discharge and dismantle batteries, producing a black mass that contains moisture that helps in the following hydrometallurgical step.

PYROMETALLURGICAL RECYCLING

This process has widely been used for nearly all types of batteries. It involves thermal treatment to decompose the components of spent lithium-ion batteries (LiBs). The process often includes two steps. First, spent LiBs enter a furnace or smelter at a low temperature to avoid hazardous explosions and to evaporate the electrolyte. Second, all plastics and solvents are burned at a higher temperature, which results in the production of slag and alloy. The alloy consists of cobalt, nickel, copper, and iron and is subsequently recycled using a hydrometallurgical method. However, most pyro processes can't recycle lithium and manganese, as they are trapped in the slag of complex materials, making the process uneconomical for most battery chemistries in the future.  

Innovation activity is low in new pyrometallurgical processes, as seen by the patent activity. A few new patents suggest that companies are patenting combined pyro-hydrometallurgical processes to reduce the overall energy spent on the process and potentially improve overall recovery rates above the dismal 50% to 60% to as much as 90%.

A good example of this is Umicore's hybrid pyro-hydro process, which involves metallurgical processing of slag containing cobalt, nickel, copper, and manganese. Unlike traditional pyro processes, where lithium and manganese are nearly impossible to recover, Umicore's process uses a selective extraction step to recover a portion of lithium.

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HYDROMETALLURGICAL RECYCLING

According to our patent analysis, hydrometallurgical processes have seen significant patent activity over the past decade as a growing alternative to pyro processes, as they are less energy-intensive and offer CAM recovery rates as high as 95%. Hydro processes use chemical precipitation via acidic reagents to dissolve the black mass of battery materials into different constituents to eventually recover key metals as metallic salts via chemical precipitation or solvent extraction. 

While companies and research groups typically rely on trade secrets and process engineering expertise for economical hydrometallurgy, many companies are patenting the entire flow sheet as well as the chemical compositions of the black mass and recovered materials. In order to retain a technical advantage early on in the market, Li-Cycle has patented the chemical composition of the black mass it produces as well as the subsequent chemical leaching/solvent extraction process. There are several other innovators in hydrometallurgy, including Duesenfeld and Volkswagen licensing the LithoRec process from the Technische Universität Braunschweig, where the mechanical shredding occurs at 100 °C to 140 °C, followed by solvent extraction for cobalt, nickel, manganese, lithium, and graphite, at a 91% recycling rate.


Lux Take: 

We expect to see continued growth in patent and research activity in battery recycling. Those interested should be actively seeking licensing or acquisition targets in this market. Several examples in the past 12 to 18 months point toward greater momentum in the industry to meet future battery demand, including TES' acquisition of French startup Recupyl's patents and strategic investment in Green Li-onFortum's buy of Crisolteq, Volkswagen's LithoRec licensing deal, Li-Cycle's $1.67 billion IPO via SPAC, BASF's partnership with Aqua Metals and Fortum, and Umicore's strategic partnership with LG Chem.

Organizations should also monitor new regulatory developments that will push regions, particularly Europe and North America, to develop an independent recycling infrastructure, moving away from what has largely been an Asia-dominated industry. A recent example of this can be seen in the European Commission's December 2020 announcement of battery recycling quotas.

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