Innovation through technology: The sustainability of lithium batteries in electric vehicles
The production of energy storage systems for electric vehicle applications using lithium-ion batteries form the basis of this bi-regional case study. The assessment draws attention to the sustainability of two stages of the lifecycle of lithium-ion batteries in order to understand resource availability and product sustainability for current and future manufacturing, not only for electric vehicles but also for other electronic devices powered by lithium-ion batteries technology.
Technology is providing new and exciting opportunities to help combat current anthropogenic issues such as climate change. Batteries in particular have become a key element in modern day society; from mobile devices and laptops to the growing markets of clean energy (such as solar panels, wind turbines, etc.) and electric vehicles. With the evolution of the rechargeable battery, society is becoming aware of the benefits it can provide, not only to people, but also to the natural environment.
In response to global efforts to reduce CO2 emissions in the transportation sector, electric vehicles (EVs) have become a growing market.1 It has been estimated that EVs will increase more than thirtyfold by 2030 (see Graph 1), competing against laptops and mobile phones for the use of lithium-ion (Li-ion) batteries.2 The growing interest in the Li-ion battery specifically is due to its long life, lightweight characteristics and its cost-efficiency, which has forecast it to have the highest potential for future energy storage technology.3 The increase in EVs has consequently increased demand for Li-ion batteries, placing a greater pressure on the sourcing of the necessary raw materials such as cobalt, graphite and lithium.4 Worldwide lithium production, for example, has increased by approximately 13% during 2017.5
Although EVs do not directly emit CO2, their overall greenhouse gas emissions depend on the fuel type used to generate the electricity that is used to charge the battery. An EV’s environmental footprint, like any product, also depends on the sustainability of the process of production, including the steps taken to produce and dispose of the battery. One way to analyse its sustainability is to carry out a life cycle analysis.6
Graph 1: Annual global electric vehicle sales are forecast to hit 24.4 million by 2030. Courtesy: Bloomberg Energy Finance
Life Cycle
A product will go through several stages before it reaches the end of its life or “use.” The life cycle of a product has five main stages: Resource Mining, Chemical Production, Product Manufacture, Product Use and Waste Management.7 Companies are becoming more aware of this life cycle and that it is important to analyse how each part of the process is carried out.8 In this particular case, two of the main stages in the life cycle of the Li-ion battery for EVs will be discussed: the resource mining of lithium and the waste management of Li-ion batteries.
The two stages will be based on the following discussions; first, the potential environmental impact of the resource extraction of lithium in Chile and options for improving sustainability, and second, sustainable and efficient waste management in the UK of Li-ion batteries no longer of capacity to power an EV. While the manufacturing stage is just as important in regard to sustainability, focus will be placed upon the direct environmental effects of the life cycle of a Li-ion battery from an EV during the extraction process, and how it is dealt with when it is no longer of use to the consumer.
The salt flats of Chile
Currently, around 70 million cars are produced globally per year.9 Around 7 million lithium ion batteries are manufactured each year, equating to enough batteries for just 10% of vehicle production.10 According to Armand and Tarascon (2008), replacing the world’s 800 million cars and lorries with electric transportation would use 30% of the world’s known reserves of lithium.11 The issue with lithium is not its availability but rather the rate at which it is being produced. 12
The Salar de Atacama in Northern Chile is one of the biggest producers of lithium salt from brine deposits (also known as evaporation ponds) in the world. 13 Extracting lithium from brines requires solar energy to allow for the evaporation of water and large dumpsites are used to store the salt residue generated during the process. 14 This can take up to 24 months.15
Although this method is more sustainable than the conventional mining of lithium, the extraction process in Chile does have a negative impact on the surrounding environment.16 Water is currently the main source of controversy as mining consumes around 65% of water available in the Salar de Atacama region.17The intense use of water in this region not only negatively impacts the surrounding flora and fauna but also the neighbouring communities, whose livelihoods rely on the already scarce supply of water. If the demand for lithium increases, as it has been forecasted to, then these issues will only intensify further.18
Improvements in extraction technology will, in part, improve the sustainability of the first stage in the life cycle of the Li-ion battery (cobalt, nickel and other raw materials used in Li-ion batteries would require similar life cycle analysis to further improve the sustainability). The European Commission has been involved in research that is developing a more innovative and sustainable method of lithium extraction from salt brines.19 The project is known as the Lithium Direct Extraction Process and if successful will not only allow for the industrialisation of high quality lithium, but will also reduce its environmental impact.
The process is an innovative alternative to solar evaporation using a solid to liquid extraction technology. Lithium-depleted brine is returned to the natural environment instead of storing it in large waste sites. In doing so, the impact on the hydric balance will be significantly reduced.20 This process would not only alleviate pressure from areas like the Atacama Desert, it would also enable lithium extraction by countries previously unable due to inadequate natural conditions for effective evaporation, such as a lack of sunshine or lower altitudes.
How rechargeable batteries are made
Once the lithium is extracted, along with the other necessary raw materials, the manufacturing of the Li-ion battery takes place. Li-ion batteries are composed of three layers: an anode, a cathode, and a porous separator.21 The anode is composed of graphite and other conductive additives. The cathode is composed of layered transition metal oxides. The product is saturated in an electrolyte solution, consisting of lithium-salt and organic solvents and sealed in a casing usually composed of steel or aluminium material to create a battery cell.22
Once the battery cell is complete, several cells are arranged to form a battery pack. The battery cells are separated within the battery pack and housed with other components, including a thermal control unit, wiring, and electronic card. Please see Diagram 1 for a more visual description of this process.23
Diagram 1: Life Cycle of a battery. 24 Source: United State Environmental Protection Agency