How green are lithium-ion batteries?

In this series, we’re unpicking the true story behind electric vehicles to understand whether they are as environmentally friendly as we’ve been led to believe.?

Earlier this week, we explored the myth that electric vehicles (EV) are just as carbon-intensive as petrol- and diesel- powered cars. We learned that a typical EV in 2018 saved 50% less carbon emissions than an ICE over the first 150,000 km (approx. 93,000 miles) – and this is only improving year on year. However, 50% of an EV’s carbon emissions is spent on manufacturing its battery: a substantial percentage that technologists are seeking to improve.?

Today, we’re looking into the effect of lithium-ion batteries on our planet, how the technology is improving and the future of a circular battery economy.?

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Rechargeable batteries are critical technology to enable the transformation to a climate-neutral society. As we search for battery technology that ensures EVs can go further and faster for even lower costs, battery technology continues to improve in leaps and bounds.

Forecasted cost per battery kWh. Source: Mauler et al. (2021).

As we explored last week, EV batteries may have a relatively high carbon cost, accounting for roughly half of an EV’s lifetime GHG emissions, but they offer the opportunity to maximise energy efficiency within a closed-loop system. What does this mean? While fossil fuels can only be burned once and must be replaced regularly - and at an increasingly alarming cost to the consumer (Bloomberg, 2022) - batteries can be recharged over and over again. And at the end of their usable life, manufacturers can use these batteries to build a brand-new battery pack or reuse them within the electricity grid.

Lithium-ion batteries are the battery of choice for EV manufacturers. They are composed of cells in which lithium ions move from the negative electrode to the positive electrode during use and back again at charging points. Battery tech is constantly evolving, getting lighter and more energy-dense (i.e. squeezing more miles of range into the same battery size).

A common misconception is that the materials required for lithium-ion batteries come from questionable and unsustainable sources. While it is true that there are challenges in transparency and sustainability in the battery supply chain, the UK Government has committed to securing a transparent, sustainable and ethical supply of raw materials, protecting the lives and livelihoods of miners (OZEV, 2022).?

Another misconception is that batteries will need replacing during the car's lifetime. With EVs likely to have an average lifetime of 200,000 miles - 70,000 more miles than ICEs - this is an understandable concern for vehicle owners who have had to replace batteries in their old ICEs (Hua et al., 2021). However, current EV batteries have been shown to last through the car's expected lifetime without issue, and EV battery life expectancy is likely to improve further with technological advances in energy density (ICCT, 2018).

Some manufacturers have committed to improving battery life. Tesla, for example, is aspiring to create batteries to last one million miles (Impact Report, 2021, p. 67). At roughly five times the average lifespan of one vehicle, this battery improvement would distribute the carbon cost of each battery significantly, reducing each vehicle's environmental impact.

However, we’re still a little way off from EV batteries lasting for one million miles – so what currently happens to batteries at the end of their lifetime? There are three options available: disposal, recycling and reuse.?

Disposal has such a detrimental environmental impact that, in the UK, existing regulations ban the disposal of EV batteries in landfills or by incineration (OZEV, 2022). If spent batteries were to be simply discarded, the valuable materials would be wasted and may lead to heavy metals and electrolytes leaching into the ground, contaminating soil and water – all causing irreversible environmental damage.?

Instead, all batteries must either be recycled or reused. Underpinning the future of sustainable EV batteries is a circular economy model: an economic system with the goal of achieving sustainable development. It replaces the ‘end-of-life’ concept with reducing, reusing, recycling and recovering materials throughout a product's life. In the UK, battery producers must take back EV batteries free of charge and ensure they treat spent batteries at permitted facilities that meet the required recycling efficiency standards (OZEV, 2022).?

Lithium-ion batteries within a circular economy. Adapted from Hua et al. (2021)

Recycling allows the valuable materials in lithium-ion batteries to be salvaged and returned to the supply chain. Modelling suggests that 99% Cobat and 93% Lithium could be recovered in a closed-loop approach typical of the circular economy, but scientists haven't yet overcome the challenge of finding a cost-effective and environmentally-friendly recycling process (Pagliaro and Meneguzzo, 2019).

In the meantime, as battery recycling technology improves, manufacturers can give EV batteries a second life by reusing them as energy storage in the electricity grid, residential services and renewable energy sources (Cusenza et al., 2019).?

Until we see substantial improvements in recycling technology, manufacturers can still give EV batteries a new lease of life through reusing them as energy storage in the electricity grid, residential services and renewable energy sources. But what about the electricity that powers them? How green is our grid? And how does it stack up against petrol- or diesel- powered cars?

Make sure to follow loveelectric and check back on Thursday as we consider how green our electricity grid really is – or click here for the full article.