For any item at the end of its working life or when it ceases to be usable in its original form the options are generally in accord with an accepted waste treatment hierarchy as below.
This is essentially an order of preference for the reduction and management of waste with the primary objective of extracting the maximum practical benefits from products whilst minimising the generation of waste. The application of this hierarchy seeks to reduce emissions of greenhouse gases, energy and pollution whilst conserving resources via virgin material displacement.
When applied to batteries that are deemed to be unusable or end-of-life the options most commonly considered are remanufacture, re-purposing or recycling which within the context of the generic waste treatment hierarchy are middle ranking options with remanufacture and re-purposing being elements of reuse.
Remanufacturing may be considered the most beneficial option as this is essentially one of repairing failed batteries in the identical configuration for reuse in the same application or generic applications.
Repurposing of end-of-life batteries is the refurbishment in a different configuration for second life usage such as stationary energy storage.
Recycling may be considered as a treatment approach to extract materials from end-of-life batteries for subsequent use. Within the scope of recycling are embraced a number of processes which essentially comprise:
Disassembly, which may be manual, semi-automated or automated, to generate such as aluminium, copper, steel, plastics and cells.
Disassembly and mechanical conditioning to generate aluminium, copper, steel, plastics or a black mass which may in turn yield lithium, cobalt nickel and copper. Pyro-metallurgy post mechanical conditioning may generate iron, cobalt nickel and copper with the hydro-metallurgical methodologies offering generation and separation of lithium, cobalt, nickel and copper.
Of these three end-of-life options, remanufacturing would appear to be more feasible and hence more cost effective than repurposing if only as a reflection of the greater level of technical challenges involved in the latter.
The recovery options may be conveniently summarised:
Recycling – considered that economy of scale is important and that the approaches and methodologies are continually evolving and are moreover sensitive to the evolution of battery technology in respect of the entrained elements.
Repurposing as an approach does not necessitate large volumes to be effective but is sensitive to the future and evolving price of new batteries as to its cost effectiveness. There are considered to be technological challenges to repurposing and additionally safety and regulatory issues will be important.
In contrast, remanufacturing also does not necessitate large volumes for cost effectiveness and whilst there are technological challenges involved there are less organisational and legal constraints in this approach.
As to the future of these approaches – given the status of the technologies and then inexorably increasing scale of market penetration and thus volumes of end-of-life batteries it may be envisaged that recycling and the economies of scale therein will become the most economical choice over repurposing or remanufacturing but that niche applications for the latter two approaches will be of significance.
The development and emergence of new recycling processes which operate at lower temperatures than existing pyro-metallurgical options and recover more valuable materials, is continuing but these have yet to be employed on any significant scale. Although some niche stationary storage applications may find second-life Li-ion batteries more affordable, the Li-ion battery driving the electric revolution is hence considered more likely to be recycled than reused.