Can electric vehicle batteries be recycled?

Serge Pelissier, September 2021

The Conversation

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When looking at the materials used in lithium-ion batteries, which are currently used in the vast majority of electric vehicles, it is important to note that there are several battery technologies. While all contain lithium, the other components vary: batteries in phones and computers contain cobalt, while those that power vehicles may contain either cobalt with nickel or manganese, or none at all in the case of iron phosphate technologies.

The exact chemical composition of these storage components is difficult to identify as it is a trade secret. In addition, improvements are regularly made to batteries to increase their performance, meaning that their chemical composition changes over time. In any case, the main materials involved in the manufacture of lithium-ion batteries are lithium, cobalt, nickel, manganese and graphite. All of these are identified as materials that present availability and environmental risks.

The issue of the availability of these materials is complex: on the one hand, the value of reserves is subject to geopolitical considerations and changes in extraction techniques; on the other hand, material requirements are highly sensitive to forward-looking assumptions (number of electric vehicles and size of their batteries).

What are the environmental impacts?

The question of the environmental impacts of battery manufacturing is perhaps even more important. Even if sufficient materials are available, the impacts of their exploitation must be taken seriously into account.

Studies show that battery manufacturing can have a significant impact in terms of human toxicity and ecosystem pollution. Added to this is the need to monitor working conditions in certain countries. Furthermore, analysing environmental impacts requires a thorough understanding of the composition and manufacturing processes of batteries, and this information is difficult to obtain for obvious reasons of industrial property rights.

Can recycling materials provide solutions to limit these risks and impacts?

There are two main families of battery recycling processes, which are used separately or in combination.

The first is pyrometallurgy, which destroys organic and plastic components by heating them to high temperatures and retains only the metal compounds (nickel, cobalt, copper, etc.), which are then separated chemically.

The second is hydrometallurgy, which does not involve high temperatures, but separates the components using different baths with compositions chemically adapted to the materials to be recovered.

In both cases, the batteries must first be crushed to obtain powders. Both processes are currently used industrially in the recycling of lithium-ion batteries from mobile phones and laptops to recover the cobalt they contain. This material is so valuable that its recovery ensures the economic viability of the current lithium-ion battery recycling industry.

However, as not all lithium-ion battery technologies used in electric vehicles contain cobalt, the question of the economic model for recycling them remains unanswered and there is not yet a real industrial recycling chain for these batteries. The main reason is the lack of sufficient volume of batteries to be processed: the widespread use of electric cars is relatively recent and their batteries are not yet at the end of their life cycle.

Moreover, the definition of end of life is itself subject to debate. ‘Traction’ batteries (which enable electric vehicles to run) are, for example, considered unsuitable for service when they have lost 20% or 30% of their capacity, which corresponds to an equivalent loss of vehicle range.

Can we envisage a second life for electric vehicle batteries?

There is therefore a debate about a possible ‘second life’ for these batteries, which would extend their use and thus reduce their environmental impact. This potential second life raises a number of challenges, starting with the necessary reconfiguration of the batteries and their electronic monitoring devices. Applications for these ‘degraded’ batteries must then be identified. One possibility is to use them for energy storage connected to the electricity grid, and numerous experiments are underway.

However, a major player such as RTE, the French electricity transmission system operator, believes that this use is not relevant, either functionally or economically, and instead recommends recycling electric vehicle batteries at the end of their first life.

Establishing a recycling chain that can adapt to evolving technologies

The establishment of a recycling chain will also require an economic model capable of adapting to the diversity of battery technologies without having to multiply recycling processes.

Finally, it should be noted that these issues of environmental impact and recycling are not easy to address for technologies that have not always reached maturity and whose long-term viability is not assured. Lithium-ion batteries are evolving very quickly – lithium-metal battery technologies, for example – and we are even seeing the emergence of competing technologies that do not use lithium, such as sodium-ion.

For all these reasons, the environmental, economic and social impacts of the manufacture and recycling of electric vehicle batteries and their materials must continue to be studied. Legislative and public pressure must continue to ensure transparency in manufacturing processes so that impacts can be quantified and ways of limiting them identified. The next European research programmes are moving in this direction by including the environmental dimension in the development of new batteries.

However, we should not expect everything from a potential miracle technology for clean, high-performance and inexpensive batteries, which is probably a pipe dream. It is important to slow down the race to increase the size of electric vehicle batteries, thereby limiting the power, weight and range of the vehicles themselves.

This requires rethinking the organisation of our mobility – moving away from the ‘car-centric’ model – rather than seeking to replace one technology (the combustion engine) with another (the electric motor).

Sources

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