Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on its ability to reacquire the properties it had in its original state.[1] It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. It can also prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, reducing energy use, air pollution (from incineration) and water pollution (from landfilling).
Recycling in the context of batteries is related to the recovery of various material components of batteries. Most types of batteries can be recycled. However, some batteries are recycled more readily than others, such as lead–acid automotive batteries (nearly 90% are recycled) and button cells (because of the value and toxicity of their chemicals). Rechargeable nickel–cadmium (Ni-Cd), nickel metal hydride (Ni-MH), lithium-ion (Li-ion) and nickel–zinc (Ni-Zn), can also be recycled. For lithium-ion batteries, the recovery of transition metals such as nickel and cobalt is motivated by their high value and potential social and environmental harm. Other components like lithium from the electrolyte and metal current collectors (aluminum, copper) are also targets of recycling. Recycling of batteries is also motivated by environmental and safety policy mandates set by governmental and regulatory bodies.
Benefits of recycling
Battery recycling has several specific benefits besides the generalized benefits mentioned above:
- Reducing the impact of metals mining on human and environmental health
- Reducing energy consumption of producing batteries, especially when recycling factory scrap or in direct recycling
- Recovery and reduced dependency of critical raw materials (CRMs) and strengthening security of supply chains
- Recovery of per- and polyfluoroalkyl substances (PFAS) in the binder
- Improved safety of normal waste disposal channels, as batteries are hazardous waste and can be damaging or dangerous to process through conventional waste disposal process chains
- Supporting the effort to develop a circular economy
Challenges of battery recycling
Battery recycling faces several technical, economic, and regulatory challenges:
- Reducing time required for safe discharge of batteries
- Dismantling and disassembly complicated by a wide variety of battery systems and designs
- Restoring battery materials to a condition which is sufficiently similar to the pristine state
- Separating battery waste streams according to their chemistries
- Achieving high yields of recycling processes
- Selectivity and specificity of target materials to be recycled
- Reducing energy intensiveness in the recycling process
- Reducing or replacing the usage of harsh chemicals in the recycling process
- Reducing costs in order to make battery recycling a feasibly viable as a business
- Economic risk to volatility in the materials commodities market
- Evolving regulatory environment which may mandate specific metrics on recycling
Steps of battery recycling
Battery recycling consists of several multi-step process chains, which can be categories as such:
- Deactivation or discharging of the battery (especially in case of batteries from electric vehicles)
- Disassembly of battery systems (especially from packs into modules and cells)
- Mechanical processes (including shredding, crushing, sorting, and sieving processes)
- Electrolyte recovery
- Metal recovery processes (including hydrometallurgical processes, pyrometallurgical processes, or direct recycling)
Hazards of battery recycling
Battery recycling is inherently hazardous to both human and environmental health due to the volatility of batteries and their material components. Some hazards can be:
- Electrical shorting and shock
- Self-igniting or self-sustaining fire
- Exposure to electrolyte solvent vapors
- Dust generation resulting in contamination and human exposure
Battery recycling policy
Policies on battery recycling created by governmental bodies vary across the globe. In some regions, regulations and practices were created by industry consortia, and in others, only local regulations apply. Recycling of specific materials such as PFAS and critical raw materials may also be subject to PFAS and CRM regulations, respectively. Battery recycling may be enhanced with the development of digital tracing such as the battery passport.
[1] Villalba, G; Segarra, M; Fernández, A.I; Chimenos, J.M; Espiell, F (December 2002). "A proposal for quantifying the recyclability of materials". Resources, Conservation and Recycling. 37 (1): 39–53. Bibcode:2002RCR....37...39V. doi:10.1016/S0921-3449(02)00056-3. ISSN 0921-3449.