Storage technologies are a necessary and growing part of our daily lives. From our cell phones and laptop computers to the vehicles we drive, batteries and other storage technologies such as flywheels, thermal storage, and hydrogen are in the news and all around us.
In fact, reductions in cost and advances in the performance and durability of batteries have led to the worldwide market for storage steadily increasing across the consumer electronics, transportation, and utility markets. With an ever-increasing supply, end-of-life performance, reuse, recycling, and eventual disposal are critical considerations, creating opportunities to actively build battery end-of-life options into the design of products.
This evolution has led industry and academia into three new areas of investigation: the repurposing of used electric vehicle batteries in grid-scale storage applications, the remanufacturing of individual modules or packs for reuse in new vehicles or other applications, and the recycling of materials in used cells and packs into new battery grade materials.
Second-life options may require less processing at lower costs than traditional sources of supply, but all three areas require further research into the costs and best processes for safe, efficient handling and screening of packs, modules, cells, and materials.
Economic and environmental benefits
In addition to the economic benefits of repurposing, remanufacturing, or recycling EV batteries, there are also significant environmental benefits. If the lifetime of EV batteries could be increased by 10 years, (through EV or grid applications), GHG emissions would be reduced by approximately 56%, based on an annual reduction rate of 2.4t CO2e per 16 kWh EV battery capacityFootnote1.
Assuming 50% of all capacities of available second-life batteries can be used for remanufacturing or repurposing, the total GHG reduction in Canada would be approximately 2 Mt CO2e in 2020, 20 Mt CO2e in 2025, 60 Mt CO2e in 2030. This is equivalent to taking 12 million gasoline vehicles off the road by 2030.
Little processing is required for repurposing EV batteries, which can retain up to 80% of original capacity once their automotive application life ends. This is likely the most efficient way to extend the life of the battery while lowering its lifecycle cost.
In 2012, GM and ABB proved this concept by repurposing used Chevy Volt batteries into a modular micro-grid energy storage system. Then in 2014, Sumitomo Corporation of Japan built a large-scale power storage system with used Nissan Leaf EV batteries.
While these projects were completed successfully, there are still gaps in the rapid and efficient assessment of state of health software, hardware challenges in battery management systems, a lack of consistent assessment of the full lifecycle economics, and the absence of a strong value chain to support the wide-scale adoption of repurposing EV batteries.
Alternatively, the remanufacturing process includes partial disassembly of the battery pack or module, removal and replacement of substandard cells, and reassembly of the module and pack. The process involves diagnostics, screening and selecting used EV batteries, following safe, reliable, and efficient methodologies. But unfortunately, widely-accepted standards for battery reuse in initial design or at end of life do not currently exist. The lack of uniformity in cell and pack designs across EV models increases the challenges in transitioning an EV battery pack, module, or cells into a second-life application.
Up to 95% of the original capacity of HEV Ni-MH batteries can be restored by a reconditioning process – an incentive to reuse HEV Ni-MH batteries in mobile and stationary applications, while decreasing the cost of battery packs for owners of HEVs. Lithium-ion chemistries are also being tested; a widely- accepted methodology has not yet been validated.
While recycling lead acid batteries from vehicles is common practice, few facilities or procedures exist to recycle Lithium-ion cells, which involves breaking the cells down into their constituent components for safe disposal or reuse in the manufacturing stream.
Another challenge is the wide variety of Lithium-ion chemistries in use, such as LMO/LFP/LMP/NCA/ NMC cathodes, Graphite, LTO, Si-C anodes, and a variety of electrolyte formulations across manufacturers.
Removing technical and market barriers
Production of electric vehicles is on the rise. As more electric vehicles are built, the number of Lithium-ion batteries entering the waste stream will increase as the batteries reach end-of-life. Navigant Research predicts that the effective energy capacity available from EV batteries for second-life ESS applications is projected to exceed 1 GWh per year by 2022, increasing to 11 GWh per year by 2035Footnote2.
NRC works with stakeholders across both the stationary and vehicle value chains to remove technical and market barriers to the effective reuse, remanufacturing, and recycling of batteries.
Specifically, NRC works with stakeholders to develop projects that:
Support battery reuse – by performing techno-economic feasibility studies to identify potential applications, benefits, and business models. Also, by working with standards development organizations to ensure codes and standards are appropriate to manage battery reuse risks.
Support remanufacturing – by working with stakeholders to improve remanufacturing processes, conduct lab-based testing, and field demonstration projects to validate the performance, durability, and safety of remanufactured battery modules.
Support recycling – by developing process and material improvements, as well as accelerated testing standards and diagnostic tools to evaluate battery state of health and state of charge to ensure safe, efficient, and high performance of recycled materials for use within the battery materials supply chain.
These initiatives build on work NRC has completed with partners such as Transport Canada, Defense Research and Development Canada (DRDC), as well as individual battery and material suppliers. Summaries are available on NRC's publication archive.