The four bottlenecks of electric cars

It is increasingly common to see an electric car rolling stealthily through the streets. Their sales have increased, including those that fit into the eco-luxury market, and they have become a viable option for more and more people. Today almost all automotive manufacturers bet the future on electric. In addition, from the institutions they are promoted as a formula against climate change and to decontaminate cities. The European Union wants there to be at least 30 million electric cars on the roads by the year 2030. By the same date, the United States has established that half of new registrations are electric, while China has set a target of 40 %.

However, its mass adoption still presents major obstacles. The typical obstacles that are usually cited for the electric motor to replace the combustion engine are its high price, the lack of a charging infrastructure and its little autonomy. But there are other difficulties, of an industrial nature, for electric cars to become ubiquitous on the roads.

graphite

In the lithium ion batteries of electric cars, the negative pole is made of graphite, one of the forms in which carbon is found in nature. It is the only material that is used for this purpose. “Carbon is a material that doesn’t seem very critical. It is very abundant in the earth’s crust,” says Belen Sotillo, a researcher at the Complutense University of Madrid in the Department of Materials Physics. “The problem with batteries is that the graphite that is incorporated has to be processed. And most of the processing plants are in China.” Hence, the European Union includes graphite on its list of critical materials; Lithium, cobalt, nickel or manganese are also on that list, all of which are components of an electric car battery.

Graphite is also the heaviest material in a lithium ion battery. It varies between 50 and 100 kilograms, according to the Kearny consultancy. This means that for every 10 million electric cars manufactured, between 500,000 and one million tons of this material will be needed. And currently the global production of graphite, for all its uses, only reaches one million tons.

Sotillo points out that they are already looking to scale up production, but acknowledges that it is very complicated. Another option is to replace it, but it is not easy either. “Once we have verified that there is an alternative and that it works well, we would have to establish that industry,” explains the researcher. “And that is often difficult. You have to move the whole industry to the new materials.”

lithium

The component for which batteries are known is the opposite of graphite. “Lithium is an element that is not very abundant in the earth’s crust, so the amount of material that could be obtained to make electric cars is limited,” says Sotillo.

The geoscientist Hannah Ritchie, from the University of Oxford (United Kingdom), made numbers on the matter. It is estimated that there are 88 million tons of lithium on Earth, but only 22 million of them are extractable. With all these reserves, Ritchie calculated, 2.8 billion electric batteries can be manufactured. It is difficult to know how many cars there are in the world, but some estimates point to a figure of around 1.4 billion. If both numbers are compared, they do not exactly give a situation of abundance. It should not be forgotten that part of the lithium will have to be used for other uses that it already has today.

“The other problem with lithium is that it is an element that tends to be very reactive. Once you have used up the battery, it is very difficult to recover it”, warns Sotillo. Physics indicates that there is also research to replace this material. “Sodium or potassium, in a battery technology similar to lithium, are elements that would have a lower capacity to store energy, but are more easily recoverable and are more abundant.”

battery recycling

Keep in mind that the battery of an electric vehicle occupies the entire chassis. And it only lasts about ten years. When the time comes to change it, the recycling odyssey begins. Felix Antonio Lopez, a CSIC researcher and head of the Recycling Laboratory of this organization, mentions a key fact: in a recycling plant, the dismantling of batteries is done by hand, since there are still no automated processes.

“Where the problems are is in the recycling of the internal battery,” says Lopez. Inside there are modules, made up of cells or batteries. “Those piles are crushed. And then separation operations are carried out, fundamentally aimed at separating plastics and copper. But these separations are not perfect. And the result is what we know as the black masses”. They are so named because of the dominance of graphite. But they also contain nickel, cobalt, manganese (from the cathode), as well as lithium, phosphorus or fluorine (present in the battery electrolyte). It is not easy to recover those items and it is costly to do so due to the lack of automation. For now, all that black mass is sent to China for recycling.

Scaling recycling is difficult, according to Lopez. The researcher calculates that there may be productive technology, which can be transferred to companies, in a horizon of five or six years. From there, it would have to be taken to an industrial scale, something that also takes time.

energy supply

Mass adoption of electric cars will also place greater demands on the electricity grid. In this scenario, Antonio Gomez Exposito, professor in the Department of Electrical Engineering at the University of Seville, distinguishes between two concepts: energy, which has to be produced in power plants, and power, which represents the speed at which deliver electricity.

“In Spain there is no relevant problem in terms of energy production,” says Gomez. And it is that at night they stop or the productivity of some thermal and nuclear power plants is reduced because they are not necessary. That is, there is infrastructure to produce more energy than the country consumes.

The limit would be in the power of the electrical network. “If everyone loads their car at peak consumption in the afternoon, as in principle would be logical, there would be a big problem, both in the transport network and in the distribution network,” Gomez emphasizes. “To avoid this, the idea is to encourage cars to charge for the rest of the night.”

Even so, in a scenario with millions of electric cars, one would expect problems in the distribution network, which involves medium and low voltage. When electricity is generated in a power plant, it goes through high voltage to a substation and, from there, it passes through medium voltage to transformer centers, which distribute electricity through low voltage wiring to homes and businesses.

“A transformation center can typically feed between 100 and 300 customers. If, of all these people, those who had cars charged them at the same time, even at night, the low-voltage radio distribution network that reaches those blocks of flats would have to be reinforced”, explains Gomez. And this would be a job that would have to be done at the local level, in cities and neighborhoods.

Coordinating vehicle charging on a large scale and upgrading part of the electrical network are two other obstacles to a massive irruption of electric cars. Although all these difficulties will only become apparent over time, as its adoption becomes more widespread.

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