Better Place is founded on the principle that we can end the world’s dependence on oil for transport, significantly reduce air pollution and take strong and immediate action on climate change by replacing petrol vehicles with electric vehicles (EVs) powered by renewable energy. Together with the financial savings that EVs can deliver, these environmental benefits are key reasons to switch to a vehicle powered by the Better Place network.
But as these EVs become more ubiquitous, questions are being asked about the life cycle of the batteries used to power them.What are they made from? Do they contain any dangerous substances? How long do they last? What happens to them when they are no longer useful? Can they be recycled?
This technical note aims to answer these questions, and explain why modern EV batteries are better for the environment than any previous battery technology, and help fulfil the sustainability mantra of the Three Rs: Reduce our use of polluting fossil fuels; Reuse our batteries for other purposes beyond their useful life in cars; and Recycle them at the end of their lives.
In the past, older style nickel- cadmium (NiCd) and lead-acid rechargeable batteries have presented a range of performance and environmental problems. Charging and discharging them at less-than-optimal charge states and times results in degradation of their internal chemicals and components, leading to battery “memory” and permanently reduced capacity, thus shortening their useful lives1. Once older-style batteries become too weak to hold sufficient charge, they can’t be thrown away - even small cells contain enough dangerous heavy metals (such as nickel, cadmium, and lead) to preclude them from disposal in landfill2. Considering the small quantities of valuable materials available for recovery from such small cells, recycling is often not economically viable. Overall, rechargeable batteries of the past were not a technology with strong environmental credentials.
Nickel-metal hydride (NiMH) technology has given us batteries that are free of highly toxic cadmium and lead, and the batteries currently used in many hybrid petrol-electric vehicles are built from these cells. Unfortunately, they still have some environmental issues: for example, the NiMH batteries used in some hybrids3 each contain many kilograms of nickel, a dangerous environmental toxin.
The latest generation of EV batteries, however, do not rely upon heavy metals to generate electricity. Their electrodes utilise the latest lithium-ion (Li-ion) chemistry, which is based on lithium, iron, phosphate (a key component of fertiliser), and graphite (a form of charcoal). These materials are not dangerous to the environment and can all be recovered in the recycling process. Furthermore, these batteries have far superior energy density to previous generations of batteries, can handle much higher charge and discharge rates, and are generally hardier than NiMH batteries4. Li-ion batteries in the latest generation EVs from manufacturers such as Nissan and General Motors feature 8 year warranties5, and can be expected to remain productive for many years6.
Looking ahead, batteries will likely be withdrawn from service in an electric vehicle when their capacity falls below 80% of their original capacity. However, second-hand EV batteries remain a valuable resource and can be put into service in a range of electricity storage applications. For example, used EV batteries can be situated in ‘battery farms’ next to intermittent renewable generators such as wind or solar to help these plants better manage the timing and rate at which they supply electricity to the grid, enabling them to earn stronger revenues as a result.
Many wind farms generate a large amount of power at night when demand from households and businesses is low. Battery storage enables electricity produced at night to be supplied during the day when it is needed.
Currently, storage for renewable energy using new batteries is prohibitively expensive: that is, in many cases the cost of the storage typically exceeds savings available from storage. By providing a significant source of second-hand batteries, EVs can provide this extra storage capacity at a much lower cost and help support the growth of the renewable energy sector.
Some major global energy services businesses such as AES Corporation and ABB Group already operate battery storage farms where it makes economic sense to do so. Their services help utilities stabilise transmission of electricity across the grid, provide a source of backup power for communities to draw on during outages and enable time-of-use management for industrial customers, who often pay higher prices for electricity during high-demand times of day7.
Used EV batteries will be in demand from these businesses as a low-cost source of electricity storage capacity. For example, ABB has signed an agreement with GM to explore applications for second-hand batteries from its Chevrolet Volt and other EVs8. When an individual battery is no longer of service in these second-life applications, it can be recycled to recover almost all of its useful materials. Battery recycling companies such as 4R Energy Corp (a joint venture involving Nissan, the manufacturer of the Leaf EV) are already emerging to take on this role. In this way, the absolute maximum use can be made of the materials from each battery.
In conclusion, modern Li-ion EV batteries will have long lives powering vehicles, followed by a ‘second life’ helping to stabilise our power grid, supporting the expansion of clean, renewable energy and reducing our carbon emissions from electricity production. At the end of their lives, the batteries are easy to recycle. Any environmental impact which may arise from battery manufacturing and disposal is insignificant in comparison to the environmental benefits of taking petrol-burning cars off our roads, and supporting the proliferation of renewable energy sources such as wind and solar power.