EV Battery Recycling and the Role of Battery Energy Storage Systems

The advent of electric vehicles (EVs) represents a paradigm shift in our approach to sustainable transportation. According to the International Energy Agency, to align with global net zero objectives, EVs will represent 60% of vehicle sales, expanding to an astounding 350 million EVs in global vehicle stock by 2030. This increasing adoption of EVs introduces significant challenges when it comes to end-of-life battery management solutions, as between now and 2030, an estimated 12 million+ tons of lithium-ion batteries are expected to retire.

On average, EV batteries degrade at a rate of 2.3% every year, maintaining their functional battery capacity within a vehicle for approximately a decade, until they reach a level of about 70-80% from their initial capacity, resulting in a dramatical decline in performance, raising important considerations about their fate thereafter. The core of this issue lies in the very composition and structure of EV batteries. Designed for durability and high performance, these batteries are an amalgamation of strategic metals and intricate engineering. Furthermore, the process of EV battery recycling and repurposing requires advanced technologies and mechanical methods to dismantle, sort, and recover these strategic metals safely and efficiently through recovery processes such as hydrometallurgy, pyrometallurgy, and direct recycling. This is not merely a task of physical disassembly but involves intricate chemical and engineering treatment to deal with the complex mix of materials present in each battery.

As EV adoption advances, it becomes imperative to address these challenges directly. Understanding the technicalities, environmental implications, and economic factors of end-of-life battery management is essential. Innovating within this space by offering alternative solutions such as second-life repurposing in battery energy storage systems to address the fundamental issue of EV battery waste is key to our progress.

Understanding the EV Battery Lifecycle: Can EV Batteries be Recycled?

Electric vehicles have revolutionized mobility by offering a cleaner, more efficient alternative to traditional ICE powered vehicles, with further promises to innovate regarding system efficiency and performance. For instance, the energy density of lithium-ion batteries has improved significantly, reaching upwards of 1,300 Wh/L or 500 Wh/kg. This improvement is central to enhancing vehicle range, charging speed, durability, and overall efficiency, pivotal in EV adoption.

Economic Viability

The economic viability of EV battery recycling is often questioned, as the cost of EV battery recycling can exceed the value of the materials recovered, especially when compared to the cost of freshly mined materials. For example, batteries made from nickel-cobalt-manganese and nickel-cobalt-aluminum chemistries are more valuable, with recovered materials potentially exceeding $25 per kilowatt-hour. In contrast, the metals in lithium-iron-phosphate batteries are worth only about half as much. The value of nickel, in particular, is a crucial determinant of the business case's attractiveness, especially as manufacturers shift to batteries with higher nickel content. This economic challenge is compounded by the relatively low volume of end-of-life batteries currently available for recycling, as many EVs are still in use.

Globally, the opportunity for EV battery recycling is expanding, with China leading in terms of capacity, capable of recycling over half a million metric tons per year, followed by the US and Europe each with about 200,000 metric tons of annual EV battery recycling capacity. The EU is planning to double its capacity by 2025. Despite this growth, most of the material available for recycling until 2035 will be production scrap, not end-of-life batteries. In fact, within the realm of EV battery manufacturing, up to 30% of batteries never make it past the manufacturing stage at newly launched factories due to quality control issues and are immediately earmarked for recycling.

Durability and efficiency of EV batteries remain areas of ongoing improvement. EV batteries are suggested to be replaced once they have degraded to about 70-80% of their initial battery capacity, normally between the 100,000 and 200,000 mile mark. While in the U.S., federal regulations require that EV batteries have a warranty covering at least 8 years or 100,000 miles, replacing an EV battery which has declined in battery capacity and surpassed its warranty can be a significant expense for EV owners, ranging from $5,000 to $15,000 or more. Influenced by factors like temperature, driving habits, and charging patterns, EV battery degradation is currently being addressed through new battery technologies and battery management systems. To fully understand the intricacies of battery degradation and how to mitigate these factors, explore our article.

As it stands, batteries represent a significant 30-40% of the cost of an EV, relying on the limited supply of raw strategic metals to fulfill the ever-growing demand of EVs. The National Renewable Energy Laboratory expects demand for these strategic metals to soar, with a 500% increase by 2050 along with a shortage of nickel within 5-6 years if current trends sustain, forcing EV battery costs to rise. Such a trend highlights the critical need to extend the lifecycle of EV batteries, emphasizing the role of a circular economy. By repurposing EV batteries for energy storage applications prior to recycling or disposal, we can effectively alleviate the mounting demand for new batteries, thereby mitigating potential shortages and stabilizing battery costs.

Environmental Concerns

Another issue is the environmental impact of EV battery recycling. While the recycling of EV batteries is technically feasible, with over 95% of a LiB’s components being recoverable, improper disposal of EV batteries poses serious environmental threats. Lithium-ion batteries, commonly used in EVs, contain heavy metals and toxic chemicals which can pollute soil and water, causing harm to ecosystems and health risks. The Journal of Energy Storage predicts that by 2025, around 2 million metric tonnes of lithium-ion battery waste will be generated globally, highlighting the urgency for sustainable disposal solutions.

EV battery recycling is not just about environmental preservation but also about resource conservation and economic opportunity. Effective EV battery recycling allows for the recovery of valuable materials like lithium, cobalt, and nickel, reducing the need for fresh mining endeavors. By doing so, it minimizes the release of hazardous substances into the environment and prevents them from leaching into soil and water sources. However, a persistent issue is the premature recycling of these batteries before their potential in second-life applications is fully realized.

EV Battery Recycling in North America

A significant advantage of recycling EV batteries in the U.S. is that the recycled strategic metals, like cobalt and nickel, are considered domestic resources. This aspect is particularly relevant under the domestic content bonus credit within the Inflation Reduction Act signed by President Biden, which includes substantial subsidies for U.S. battery production into the 2030s. Once these strategic metals, initially sourced from abroad, excluding China, are recycled in the U.S., they are reclassified as U.S.-sourced. This reclassification aids in aligning with the bill's provisions and supports the domestic battery production industry.

Current Strategies for EV Battery Recycling

The landscape of EV battery recycling currently faces several significant limitations that impact its efficiency and feasibility. However, in contrast to liquid hydrocarbons, which lose their energy value after being used as fuel, even though the battery capacity deteriorates over time, certain elements used in EV batteries such as cobalt maintain their intrinsic properties regardless of the number of times they're utilized in battery production, proving extraction of these strategical metals from end-of-life EV batteries to become a valuable resource to be reused into new EV batteries rather than mining for new material.

Hydrometallurgical and pyrometallurgical processes are two primary methods used for recycling EV batteries. Each has its distinct approach and advantages:

Hydrometallurgy for EV Battery Recycling

1. Dismantling and Shredding: Initially, the EV batteries are dismantled, and the cells are shredded into smaller pieces. This process helps in breaking down the battery into its composite materials.
2. Leaching: The shredded material is then subjected to a leaching process where chemicals, usually acidic solutions such as sulfuric acid, are used to dissolve the metals. This step is crucial for the extraction of valuable materials like lithium, cobalt, nickel, and manganese, while minimizing the dissolution of unwanted materials.
3. Solid-Liquid Separation: After leaching, the slurry contains dissolved metals in the liquid phase and undissolved waste materials in the solid phase. These two phases are separated using techniques like filtration or centrifugation.
4. Purification and Concentration: The leach solution, now containing the valuable metals, undergoes several purification steps to remove impurities. Techniques like solvent extraction, precipitation, and ion exchange are commonly used. This stage is crucial for increasing the purity of the extracted metals.
5. Metal Recovery: After leaching, specific methods like solvent extraction, precipitation, or electro-winning are used to recover the individual metals from the solution. These processes separate and purify the metals, making them suitable for reuse. The process generates waste materials, including spent leaching solutions and non-metallic residues. These need to be treated and disposed of in an environmentally safe manner, often involving neutralization of acids and management of any toxic substances.

Pyrometallurgy for EV Battery Recycling

1. Pretreatment and Crushing: This initial step involves disassembling the EV batteries, removing non-metal components, and then crushing the battery cells. This process prepares the materials for high-temperature treatment by exposing the valuable metal components and enabling easier separation.
2. Thermal Treatment and Smelting: The crushed materials undergo thermal treatment (pyrolysis or calcination) to decompose organic materials and remove volatile components. Following this, the smelting process involves melting the residue in a furnace, often with fluxes added, to separate metallic components from slag.
3. Metal Separation and Purification: In this step, the molten metals are processed to separate and purify the different valuable metals. This can involve chemical or electrochemical methods, refining the metals to a high degree of purity.
4. Solidification and Casting: The purified metals are cooled and solidified, typically in molds, to form ingots or other usable forms. These metal products can be utilized in various applications, including new battery production.
5. Waste Management and Slag Utilization: The final step involves handling the slag and other waste materials generated during the process. The slag, if non-toxic, can sometimes be repurposed in construction materials, while any hazardous waste must be treated and disposed of in an environmentally responsible manner.

Direct Recycling of EV Batteries

1. Discharging and Disassembly: The first step involves safely discharging the battery to eliminate any stored energy, reducing the risk of electrical hazards during subsequent handling before being carefully disassembled, often manually, by removing the battery modules and cells from the casing, along with the electronic components and thermal management system.
2. Cell Sorting and Refurbishment: The individual components, especially the cells, are sorted based on their chemistry and condition. Cells that are identified as viable for reuse undergo refurbishment, which can include processes like cleaning, drying, and repairing any minor physical damages. The goal is to restore the cells to a condition suitable for their incorporation into new battery assemblies.
3. Cathode and Anode Separation: Separation involves removing the cathode and anode materials from other components like separators and current collectors. This can be done mechanically, such as by shredding or crushing the cells, followed by processes like sieving, air classification, or magnetic separation to isolate the valuable materials.
4. Material Processing: The separated cathode and anode materials undergo processing to restore their original properties. This can involve various techniques, including chemical treatment to remove impurities or re-lithiation processes (reintroducing lithium) for the cathode material. The goal is to rejuvenate these materials so they can be reused in new batteries.
5. Reintegration into New Batteries: The final step involves integrating the recovered and processed materials into new battery production. This includes using the recycled cathode and anode materials to manufacture new battery cells, which are then assembled into modules and packs, ready for use in new EVs or other applications.

Each process plays a vital role in the world of EV battery recycling, and the choice between them often depends on the specific battery chemistry, available technology, and environmental considerations. Hydrometallurgy, the most flexible and environmentally friendly method, is preferred for its efficiency in recovering a wide range of strategic metals and is particularly suitable when high purity of these materials is desired, making it ideal for a broad spectrum of lithium-ion batteries. Pyrometallurgy, on the other hand, is often chosen for its robustness and suitability for large-scale operations, especially effective in recovering metals like cobalt and nickel but less so for lithium and is favored where energy consumption and emissions are less of a concern. Lastly, direct recycling is best suited for scenarios where preserving the original properties of battery materials is paramount and where the condition of the returned batteries allows for effective material recovery, pointing towards a more sustainable but technically challenging approach.

Introducing Second Life with Battery Energy Storage Systems

Battery energy storage systems are emerging as an optimal solution to the challenges posed by end-of-life EV batteries beyond mere EV battery recycling, offering a sustainable path to repurposing batteries to support the circular economy. Battery storage technology not only tackles the environmental issues associated with battery waste but also supports EV adoption by reducing the demand and strain on our electrical grids that results from the surge in EV charging.

The concept of repurposing EV batteries for energy storage applications is a practical way to extend their lifespan beyond their initial vehicle use. Once an EV battery's capacity dips below the ~80% threshold after about 10 years of driving use, it may no longer be ideal for powering vehicles, but it still possesses a considerable amount of energy storage potential. This remaining battery capacity can be effectively utilized in various secondary applications, such as providing backup power for buildings or contributing to the stability of both local and national energy grids.

The process of utilizing battery energy storage systems to extend the utility of EV batteries into a second life involves several key steps. This approach not only makes the most of the leftover capacity in these batteries but also contributes to environmental sustainability by reducing waste.

1. Assessment of Battery Health: The first step in repurposing EV batteries for battery energy storage is to assess their state of health and remaining battery capacity. Even after their battery capacity diminishes in EVs, these batteries can still retain a significant amount of charge, typically around 70-80%. This assessment is crucial to determine the viability of batteries for their second life and involves checking for factors like battery capacity, energy efficiency, and any potential damage or degradation.
2. Integration into Battery Energy Storage Systems: Once deemed suitable, these cells are then grouped into battery packs of similar state of charge and state of health to operate optimally once integrated into battery energy storage systems. These systems can be used for a variety of applications, such as storing energy from renewable sources like solar or wind, providing backup power, or helping to balance the grid during periods of high demand or low production. The integration process often requires reconfiguring the battery packs to suit their new application, which can include adjusting their voltage, battery capacity, and management systems to ensure they operate efficiently and safely in their new role.
3. Battery Management and Optimization: A critical aspect of using repurposed EV batteries in battery energy storage systems is the management of the battery’s capacity to maximize its lifespan and efficiency. This involves continuous monitoring and management of battery charging and discharging cycles, temperature control, and balancing the cells within the battery. Advanced battery management systems, often leveraging artificial intelligence and machine learning, are used to optimize these processes, ensuring the batteries are used in a way that extends their life and maintains their performance.
4. Extending Battery Life and Reducing Waste: The primary benefit of this approach is the extension of the battery's lifecycle. Instead of disposing of the batteries when they are no longer suitable for use in EVs, repurposing them for battery energy storage systems can extend their useful life by an additional 5-10 years. This not only makes the most of the materials and energy that went into manufacturing the batteries but also significantly reduces waste and the environmental impact associated with battery production and disposal.
5. Future Recycling: Once the batteries finally reach the end of their second life in battery energy storage systems, they can then be sent for EV battery recycling. At this stage, valuable materials such as lithium, cobalt, and nickel can be recovered and reused, further contributing to the circular economy, and reducing the demand for new raw materials.

Repurposing EV batteries for use in battery energy storage systems is an effective way to extend their lifecycle, making the most of their remaining battery capacity, and reducing environmental impact. This approach not only provides a practical solution for managing the growing number of end-of-life EV batteries but also supports the transition to more sustainable and renewable energy systems.

Exro’s Innovative Approach with Cell Driver™ Technology

Exro Technologies has developed an innovative approach to extending the utility of EV batteries into a second life through the Cell Driver™ Battery Control System™, pushing the boundaries of control by actively managing each individual cell based on its state of charge and state of health. This level of governance allows for cells to be mixed and matched without concern over varying characteristics amongst a battery pack. Not only does this streamline the process and reduce the associated time and cost, it also increases the amount of EV batteries that pass through for repurposing, contributing to the circular economy.

The Cell Driver™, designed for commercial and industrial applications showcases several additional key features that contribute to extending the life of EV batteries when repurposed for energy storage. The system utilizes advanced dynamic micro-protection mechanisms for current, temperature, and voltage. This ensures unparalleled safety in the operation of the battery energy storage system, minimizing the risk of cell-level thermal runaway. Additionally, the unit can electronically isolate defective cells without impacting overall system operation. The technology within the Cell Driver™ introduces an innovative topology for active cell balancing. It drives each cell with alternating current, dynamically adjusting the amperage per second based on each cell's state of charge and state of health. This leads to consistently balanced cells and matches power demand and quality, enhancing the battery capacity, efficiency, and safety of the battery energy storage system.

Furthermore, the Exro Cell Driver™ strategically implements load shifting and peak shaving strategies by charging during off-peak times and discharging during peak demand periods, in turn flattening peak demand, reducing demand charges, and optimizing battery charge and discharge based on time-of-use benefits.