In recent years we have seen the rise of the electric car. Although the first attempts to introduce electric batteries date back to the early decades of the 20th century, it is now that electrified cars promise to revolutionize the industry due to their (almost) zero emissions and absence of noise, in line with the needs of the energy transition and new models of mobility worldwide.
However, the electric car does not represent today more than 3% of the registrations in almost any country, and that is because, to achieve its widespread expansion, the electrified vehicle must overcome important challenges such as battery autonomy, recharging networks and its price.
At present, the problem of electric car autonomy is compounded by the inadequacy of a widespread network of recharging points. Despite having become part of the urban furniture in large cities, these points are still limited in the rest of the territories, making long or non-urban journeys in an electric car difficult or even impossible on many occasions.
Furthermore, charging time is another barrier today, as the batteries of today’s electric vehicles take an average of eight hours to achieve a full charge, which can be reduced to one or two hours at accelerated charging points and, only in specific models, there is rapid charging (43 kW) in less than an hour. The ideal dream scenario is inductive charging, where the car is recharged while driving, but today’s technology is still far from achieving this milestone in any significant way.
Batteries: a shortage of raw materials
Batteries are the key challenge in automobile electrification. China, South Korea and Japan are leading the way in the manufacture of this component, which is essential for future mobility, while Europe faces a problem of dependence, as 85% of batteries are produced outside the EU.
The difficulty lies in the raw materials from which the batteries are made: mainly graphite, lithium and cobalt. Regions such as Europe lack their own sources of these minerals, although they have improved in recent years in the refining of these raw materials, which is also dominated by China. Bolivia and Chile are two of the main lithium reserves, while cobalt comes mainly from the Republic of Congo. However, the current reserves will not be sufficient to reproduce a vehicle fleet similar to the current one, so innovative solutions are increasingly being sought to find technologies that use alternative sources.
Solid state batteries
A lithium battery consists of two metal electrodes and a separator, called an electrolyte, which prevents them from touching each other. In lithium batteries, the electrolyte is a liquid or gel in which the electrodes are immersed, and which has the disadvantage that it is flammable, so it requires many safety procedures that make its manufacture more expensive.
However, in solid state batteries, the electrolyte is a solid substance (often sodium-based glass). Therefore, a solid state battery can store three times more energy than a lithium ion battery and recharge in less than an hour. It also provides more safety because it does not contain incendiary liquid, and it extends the life of the battery because the solid material degenerates less than lithium.
Solid batteries therefore have a very long life cycle and do not need cobalt, nickel or manganese, facilitating their recycling within the desired circular economy.
However, the great challenge lies in its mass production process, as it is a technology in an early stage of development and research is still being carried out on how to manufacture it at low cost and on a large scale, as it would currently be too expensive to be widely adopted in the market. There are companies exploring alternatives such as full 3D printing on a single machine, but there is not yet a standard procedure that would allow its generalisation.
Other alternative batteries in early stages of research
- Liquid batteries, but cobalt and nickel-free: IBM has discovered an alloy of materials that does not require conflicting ingredients such as cobalt or nickel and has materials that can be extracted from seawater. These would offer greater safety by reducing flammability, as well as faster charging time, higher energy density, and high energy efficiency.
- Lithium-sulfur battery achieving 1,000 km range: An Australian research team has reconfigured the design of sulfur cathodes to accommodate higher voltage loads without a drop in capacity or overall performance, so that 1,000 km range could be achieved between charges, although the safety issues etc. presented by the lithium batteries currently in use are not solved.
- Replacing lithium with calcium: a team from the University of Cordoba (Spain) has studied the intercalation of calcium in molybdenum oxide and is studying the reactions between the components of the battery, opening up new lines of research.
- Grafene supercapacitors: Grafene is considered to be one of the nanomaterials of the future. It can be used to manufacture capacitors that have already been installed in some vans by a firm in Singapore. These batteries would have much greater capacity, ease of recycling and better performance.
- Organic batteries: these use abundant organic matter to store energy. They use the electromagnetic properties of materials present in nature in a sustainable way, such as quinone, a lignin molecule that is the most abundant plant polymer in the world.
Increasingly, the industry is working to develop electric car components with sustainable materials and processes. The tendency is to escape from cobalt and other materials traditionally used in this sector, in order to give priority to new materials that are more efficient, less contaminating and that allow recycling within a circular economy model.
Part of this scenario will also be formed by the energy source itself with which the batteries of the autonomous cars are recharged. At a time when renewable energies are booming worldwide, more and more people are looking to make progress along these lines, and the possibility of recharging through carbon dioxide is even being studied.
In any case, if the number of electric vehicles increases exponentially, massive energy storage systems will be necessary to cover the demand peaks, a field in which the lithium-ion continues to prevail, with the consequences and limitations that it entails, and therefore other alternatives are also being sought.