Recycling Electric Vehicle Batteries: Four Effective Methods
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Credit: This article is based on the scientific work titled “Literature Review, Recycling of Lithium-Ion Batteries from Electric Vehicles, Part I: Recycling Technology” by Anna Pražanová, Vaclav Knap, and Daniel-Ioan Stroe (Full citation and link available at the end of the article).
Fossil fuels are under scrutiny for their detrimental effects on the environment. The combustion of fossil fuels releases CO2 that has been sequestered in the earth for millions of years into the atmosphere. As natural processes cannot immediately absorb all of this CO2, atmospheric levels continue to rise, contributing to climate change driven by human activity. This underscores the necessity for alternatives to fossil fuels, particularly for transportation. For a deeper dive into alternatives, refer to my article on Electric, Hydrogen, or Biofuel Cars: Which Will Help Save Our Planet?
One viable alternative is the adoption of electric vehicles (EVs). When powered by solar energy, the carbon footprint of EVs is significantly lower than that of fossil fuel-powered vehicles, as they do not emit CO2 while in operation. Furthermore, with fossil fuel prices soaring, the appeal of electric vehicles is on the rise. However, there remains a critical challenge to address.
This challenge stems from the reliance on lithium-ion batteries in electric vehicles. These batteries are also common in consumer electronics like smartphones and laptops. Unfortunately, the extraction of lithium raises environmental, social, and economic issues. At the end of their life cycle, typically after 15-20 years, these batteries contribute to landfill waste. Additionally, the working conditions for miners can be hazardous. Thus, it is crucial to either innovate alternative battery designs or focus on recycling lithium-ion batteries.
Recycling lithium-ion batteries from electric vehicles poses a challenge due to their complex composition. Some methods require pretreatment before recycling can occur, which can be executed on both small laboratory and large industrial scales. The pretreatment process on a small scale involves three key steps:
- Completely discharging the battery to minimize the risk of short-circuiting and heat generation from chemical reactions.
- Manually dismantling the battery casing to retrieve materials.
- Separating the various components, often through processes like dissolution or decomposition.
This method is effective for recovering valuable metals but is impractical for large volumes of batteries. In contrast, industrial-scale pretreatment encompasses seven steps:
- Full battery discharge, though the method may differ from small-scale processes.
- Manual disassembly using knives and saws, as few automated tools exist for this task.
- Mechanical crushing of parts to release electrode materials, with repeated crushing enhancing the recovery of lithium, cobalt, manganese, and nickel.
- Sieving to roughly separate different materials.
- Using various techniques for more precise component separation, such as magnets.
- Dissolving remaining binders to free attached materials.
- Heating the materials to 900°C (1652°F) to release any remaining substances.
Once pretreatment is complete, the battery can be recycled. The following methods outline how this can be achieved:
Pyrometallurgy
The initial method is pyrometallurgy, which involves subjecting old batteries to high temperatures within a furnace. Elevated temperatures facilitate material phase transitions, such as from solid to gas. Several pyrometallurgical processes can be utilized at high temperatures:
- Roasting: Chemical reactions occur between gas and solid particles at elevated temperatures.
- Calcination: Battery materials are heated to a high temperature below their melting point, resulting in dissociation into simpler compounds.
- Smelting: The materials from the retired battery are liquefied under high temperatures.
Pyrometallurgy offers multiple advantages: no prior pretreatment is necessary, various battery types can be recycled, and over 90% of materials can be recovered. However, it is energy-intensive, low-cost lithium-ion batteries yield waste during the process, and it generates toxic gases requiring treatment.
Hydrometallurgy
The second method is hydrometallurgy, which necessitates pretreatment and involves chemical reactions in a liquid medium to extract valuable components from batteries. This approach can be employed independently or as a follow-up to pyrometallurgy.
The chemical reactions occur in stages, each producing different end products:
- Leaching: Acids dissolve valuable metals. Various leaching techniques optimize material recovery for different battery types.
- Impurity Removal: Solid particles are separated from the liquid through centrifugation or filtration.
- Metal Recovery: Nickel, cobalt, manganese, and lithium are recovered, often in the form of metal salts.
Hydrometallurgy boasts numerous advantages: it can treat almost all battery types, is highly efficient, generates no emissions, and produces pure end products. However, it also has drawbacks, including the need to crush batteries, significant wastewater production, unrecoverable materials like graphite, and high costs.
In this video, you can observe a company pretreating batteries and employing hydrometallurgy for recycling electric vehicle batteries. Their method reduces the carbon footprint of lithium-ion batteries by 40% (0:39–4:05):
Direct Recycling
The third recycling method is direct recycling, which treats batteries in a manner that preserves certain components while cleaning them. This means not all parts are decomposed, as in pyrometallurgy and hydrometallurgy, allowing for the recovered components to be reused in new batteries.
Direct recycling employs various techniques, such as crushing batteries and separating parts, followed by moderate heat exposure. Another method utilizes ultrasound to eliminate contaminants.
Direct recycling offers several benefits: all materials can be recycled, it can effectively treat specific battery types unsuitable for pyrometallurgy and hydrometallurgy, and it avoids the high temperatures or strong acids, making it cheaper, easier, and less resource-intensive. However, it also presents challenges, including complicated pretreatment and lower quality output products.
Special Recycling
The fourth method is special recycling, which encompasses specialized techniques for recycling old lithium-ion batteries. These methods vary widely. For instance, one approach involves crushing batteries, applying chemicals to extract valuable materials, and using acids for further metal recovery. Another method grinds batteries and treats them in water to leach out valuable components.
Conclusion
In summary, electric vehicle batteries can be recycled through pyrometallurgy, hydrometallurgy, direct recycling, and special recycling techniques. Some methods necessitate battery pretreatment to maximize material recovery.
How We Can Take Action
Here are some practical steps we can take to recycle used lithium-ion batteries from electric vehicles:
- Return old car batteries to a recycling facility.
- Donate dead electric vehicle batteries to someone who can repurpose the materials.
- Choose manufacturers that prioritize battery recyclability.
- Support petitions encouraging policymakers to promote battery recycling initiatives.
If you have additional ideas on how we can contribute, please share them in the comments to inspire others.
Credit
This article is based on:
Pražanová, A., Knap, V., Stroe, D.-I. Literature Review, Recycling of Lithium-Ion Batteries from Electric Vehicles, Part I: Recycling Technology. Energies 2022, 15, 1086.