Redwood Materials operates a secure, domestic, and circular battery supply chain focused on recycling end-of-life lithium-ion batteries from electric vehicles and consumer devices. Through collecting these batteries, the company refines the recovered materials and remanufactures them into essential components. Redwood is targeting minimum recycled content thresholds of 20% recycled nickel, 20% recycled lithium, and 50% recycled cobalt in cathode materials, along with 100% recycled copper for anode foil.
Redwood Materials’ sustainable infrastructure
Redwood Materials is addressing two of the clean energy industry’s biggest challenges. These are creating a sustainable, domestic supply of battery materials and meeting rising electricity demand from AI data centers. Founded by former Tesla CTO JB Straubel, the company recycles used batteries and manufacturing waste to recover valuable metals.
Redwood’s Series E financing increased from the initially announced $350 million to a final close of $425 million. The company has also expanded its research and development operations, recently quadrupling the footprint of its San Francisco R&D laboratory. The facility supports engineering work across mechanical, electrical, and systems disciplines, with laboratory infrastructure for developing and testing energy storage technologies.
From EV packs to AI infrastructure
The main engineering challenge in repurposing retired EV batteries is the diversity of battery designs. The market includes more than 100 battery electric vehicle models with different chemistries, architectures, voltages, and software controls. Redwood addresses this through its Pack Manager technology platform, which integrates different battery packs into stationary storage systems. Packs that meet the requirements for second-life use are directed to Redwood Energy, while others are processed for materials recovery and critical mineral extraction. Redwood has also deployed storage systems for AI infrastructure providers such as Crusoe, extending the use of retired EV batteries beyond automotive applications.
Redwood Materials: Patenting Activity
Redwood Materials’ activity peaked in 2022, with patent filings reaching their highest level during a period of significant business and technological expansion. The timing coincides with several major developments that year as Redwood broadened its role beyond battery recycling and further into the production of battery materials. TIME highlighted the company’s growing relationships with major companies in the electric-vehicle sector, including Ford and Panasonic.
This expansion was further reflected in Redwood’s partnership with Toyota to collect, refurbish, and recycle batteries and battery materials for use in Toyota’s battery manufacturing operations. The partnership also demonstrated Redwood’s move further downstream from conventional recycling into the production of anode and cathode components.
Redwood was also expanding internationally during the same period. In February 2022, the company announced its expansion into Europe, with plans to replicate its circular battery supply-chain model by combining recycling, refining, and remanufacturing and establishing partnerships with European automakers and battery-cell manufacturers.
Redwood Materials: Top Technology Areas
Redwood Materials’ patent portfolio is concentrated in technologies directly related to battery manufacturing, critical material recycling, and clean energy sustainability.
Battery energy conversion processes (H01M), greenhouse gas emission reduction in energy generation and distribution (Y02E), structural and physical characterization of solid inorganic compounds (C01P), and climate change mitigation in waste management (Y02W) account for the largest share of patent classifications. This concentration highlights the company’s core focus on recovering critical minerals from end-of-life batteries and remanufacturing high-value battery components like cathode active materials and anode copper foil.
Beyond core battery chemistry and waste treatment, the portfolio includes patents related to metal production and refining (C22B), specific metal compounds (C01G), specialized fire-fighting systems (A62C), and industrial transport or conveyor devices (B65G). It also covers refuse gathering and removal (B65F) alongside climate change mitigation in goods manufacturing and processing (Y02P). The breadth of these CPC classifications reflects Redwood Materials’ strategy of protecting not only its primary recycling and refining processes, but also the supporting material handling, safety protocols, and industrial manufacturing logistics required to scale its domestic closed-loop supply chain.
Securing the battery lifecycle
Redwood Materials’ patent portfolio covers technologies across the battery recycling process, from safe battery collection and transport to the recovery of valuable materials. The following patents highlight these technologies and their role in Redwood’s recycling operations.
Closed-loop hydrometallurgical refining for battery materials
Recycling lithium-ion battery manufacturing scrap and end-of-life EV batteries requires hydrometallurgical processes that can efficiently recover battery-grade nickel, cobalt, and lithium. As battery production expands, conventional methods that rely on sequential solvent extraction and sodium-based reagents such as sodium hydroxide and sodium carbonate can generate large volumes of sodium sulfate waste. Separating lithium from sodium in these waste streams requires additional crystallization steps, increasing capital and operating costs, energy use, and environmental impact.
U.S. Pat. App.Pub. No. 2024/0250327 describes a system that uses calcium-based reagents and closed-loop chemical recovery to reduce these waste streams. The process extracts valuable metals from battery manufacturing scrap or black mass, producing nickel-containing materials such as mixed hydroxide precipitate (MHP) or precursor cathode active material (pCAM), along with a purified lithium sulfate solution. By replacing sodium-based reagents, the process avoids generating sodium sulfate as a byproduct.
The process begins with mechanical separation to remove structural metals such as aluminum, iron, and copper and produce a refined black mass. The black mass is then leached with sulfuric acid, with or without hydrogen peroxide, to transfer lithium, nickel, and cobalt into solution. Calcium-based reagents such as hydrated lime or limestone are added to raise the pH and selectively precipitate base metals, producing nickel-containing products and gypsum. Remaining calcium is removed using carbon dioxide or soda ash to form calcium carbonate, which can be recycled into the process. Finally, the purified lithium sulfate solution is processed to produce lithium hydroxide or lithium carbonate, while regenerated sulfuric acid is returned to the leaching stage.
The patent application, titled “Methods of Purifying and Precipitating Materials from Batteries for Recycling and Manufacturing Processes,” was filed on January 19, 2024, and published on July 25, 2024, claiming priority to a provisional application filed on January 20, 2023. The applicant is Redwood Materials, Inc., and the named inventors are Paul Voigt, Jackson Switzer, and Mary Lou Lindstrom.
Reusable packaging for safer battery transport
The rapid growth of electric vehicles and energy storage has increased demand for battery manufacturing and recycling infrastructure. However, collecting, storing, and transporting spent lithium-ion cells and manufacturing scrap presents logistical and safety challenges.
Conventional methods often rely on manual handling, disposable packaging, and bulky containers that provide limited protection against short circuits, electrolyte leakage, and thermal runaway. At larger volumes, these approaches also increase material waste, freight costs, and safety risks.
U.S. Pat. App. Pub. No. 2025/0236433 describes a modular battery storage and transportation system designed for high-density, reusable logistics. The system uses interlocking storage trays that hold individual battery cells in dedicated cavities, allowing large quantities of cells to be safely stacked and palletized without disposable packing materials.
The trays are made from durable, non-conductive, electrolyte-resistant materials such as recycled high-density polyethylene (rhDPE). Each cell is held vertically in a slot with a terminal isolation cavity that helps prevent accidental contact, short circuits, and mechanical damage. The staggered slot design allows trays to interlock and overlap when stacked, increasing storage density on standard 48-by-40-inch pallets while maintaining clearance for robotic handling. Double-layer walls can also contain air gaps or fire-suppressant materials such as vermiculite or expanded clay, while overhanging edges help protect cells from dust and water. Filled trays are secured with webbed belts and steel buckles to form reusable pallet loads for transport.
The patent application, titled “Battery Storage and Transport System,” was filed on January 22, 2025, and published on July 24, 2025, claiming priority to a provisional application filed on January 23, 2024. The applicant is Redwood Materials, Inc., and the named inventor is Jacob Daniel Goodman.
Automated collection for safer battery drop-offs
Unsorted spent batteries can retain electrical charge and pose fire risks if they are damaged, crushed, or short-circuited during storage or transport. Conventional collection methods often require trained staff, manual taping of battery terminals, or specialized fire-resistant packaging, making public collection difficult to scale.
U.S. Patent No. 12,496,476 describes an automated battery collection bin designed for unsupervised consumer drop-offs at retail stores, grocery stores, and community locations. The system accepts batteries and electronic devices without requiring individual packaging or staff assistance, then automatically detects each deposit and dispenses a measured amount of mineral-based fire suppressant to reduce the risk of thermal runaway.
The bin uses sensors to monitor the deposited material and control the suppression process. Ultrasonic sensors, weight scales, thermal detectors, and carbon dioxide monitors assess the contents, while an automated mechanism releases materials such as vermiculite, perlite, or expanded clay into an internal transport drum. Safety features include access controls, pressure venting, and a thermal hatch that can release additional suppressant if temperatures rise. When the drum is full, remote monitoring alerts service teams, who can remove the sealed drum for transport to a recycling facility.
The patent, titled “Battery Collection Systems and Methods of Using the Same” was filed on October 12, 2023, and granted on December 16, 2025, claiming priority to a provisional application filed on December 29, 2022. The listed inventors are Jackson Switzer, Alexis Georgeson, Mike Joyer, and Haley Ketterer. Legal representation was provided by Keller Preece.
Redwood Materials: Top Law Firms
Redwood Materials has engaged a broad range of law firms for its global patent and patent application activity from 2016–2026, including KBK & Associates, Ohtsuka Patent Office, Beijing HengLv IP, Aoyama & Partners, Y.P. Lee, Mock & Partners (now LEE & MOCK IP), Stikeman Elliott, Kangxin Partners, Keller Preece, and Blackwattle IP. These firms reflect the company’s use of patent counsel across several international jurisdictions and highlight the global scope of Redwood Materials’ intellectual property activities.
