Are electric cars more environmentally friendly than conventional cars? How are batteries produced? What happens when an electric car battery has outlived its usefulness? What about the disposal of batteries? This blog will inform you about the battery life cycle – and what the future may hold.
Although battery production and disposal create some problems, electric cars are still better for the environment than cars with internal combustion engines. Through the use of green electricity, an environmental balance is reached after 30,000 kilometres. Even with the current German electricity mix (approx. 35% coal-fired electricity), the threshold lies at 50,000 km. This means that the use of electric vehicles is much more environmentally-friendly, as it does not generate any direct CO2 or NOx emissions. Global research on recycling and alternative energy storage systems also shows that electric vehicles have great future potential.
Electric car batteries are extremely energy efficient. The efficiency of a diesel or petrol vehicle is around 35%, a fuel cell vehicle 60% and an electric vehicle 95%. In addition, battery-powered vehicles are significantly less susceptible to faults and material wear.
Batteries used in an electric car have reached the end of their life after 7 to 10 years. In fact, at this point, the performance is reduced to only 70 or 80% of the original capacity. This is why so-called second-life applications for batteries – life after death – are already being implemented today. Retired batteries can be used as stationary energy storage devices. Bundled into large packages, they can be used as intermediate storage for buildings with fluctuations in availability of renewable energy sources. According to Daimler AG, it will be possible to operate such a system for at least 10 years.
But what happens then? Many assume lithium-ion batteries cannot be recycled. This is far from the truth. Currently, the German government specifies a recyclability rate of at least 50%. The industry’s targets are even more ambitious: the Finnish company Crisolteq, for example, has a recycling rate of over 80% for lithium-ion batteries. In 2020, a Volkswagen recycling plant will go into operation in Salzgitter. Thousands of batteries a year can be recycled at this facility. The long-term goal is to recycle 97% of all raw materials.
Emissions during the production phase of batteries depend on the place of manufacture and therefore fluctuate greatly. It is important for the environmental footprint that the energy used for this comes from renewable sources. This is currently already the case at production sites in France and Norway. According to an ADAC (General German Automobile Club) study, the production of electric vehicles (including batteries) currently generates more than twice as much CO2 as petrol or diesel cars. As was previously mentioned, however, these additional emissions will be amortized in the short to medium term when the vehicles are in use. This time can be shortened by the full use of green electricity.
The production of lithium-ion batteries currently installed in all electric vehicles requires a large amount of raw materials. The main elements – lithium and cobalt – belong to the so-called rare earth elements. Compared to the 2-3 grams needed to make a smartphone, electric vehicle batteries require several kilograms. The problem with rare earth elements is that global reserves are limited and their degradation can have negative ecological effects. They are also to a large extent located in politically-unstable regions. Especially in Chile, lithium mining worsens the living conditions for Chileans due to water shortages. The most environmentally-friendly raw material is currently mined in Iceland. Some also argue that electric cars contribute to the continuation of child labour practices and environmental pollution. A little bit of research will show, however, that the process of extracting oil to power conventional vehicles has a far more harmful effect on humans and nature.
It is particularly important to increase the recycling rate of batteries to limit the amount of mining for new natural resources. Another option is the development of alternative battery system. As this is a very profitable field, extensive research is currently being conducted worldwide. There are already numerous promising developments.
The sodium ion battery – also known as the post-lithium battery or salt water battery – does not require rare earth elements for production. Sodium is 1000 times more abundant on earth than lithium, and is easier to degrade. Other advantages are lower weight, lower price and greater safety. However, technical improvements and material optimisations are still necessary before the product is ready for market introduction.
Research is also being carried out on magnesium ion batteries. Compared to lithium-ion batteries, the use of magnesium enables an even higher energy density, and thus greater performance. In addition, they are safer – just like sodium ion batteries – and exhibit hardly any interference or short circuits. In addition, they are the most environmentally-friendly variant to date: magnesium is 3,000 times more abundant on earth than lithium, and is also easy to recycle. The greatest challenge of this battery technology is its service life, which must be extended considerably before it can be used in everyday life.
In addition to these battery systems, many other promising storage options are being researched. Examples are the redox flow battery, which has a very long service life, or the fluoride ion battery, which is ten times more efficient than a lithium ion battery.
