‘It’s down to the battery now’

Almost everyone is driving an electric car these days, packed with trendy gadgets. At least, that is the impression you get watching television commercials. Looking around on the road, the actual impression is quite different. Of all new cars that rolled out of the showroom in 2020 in the Netherlands, about twenty percent was fully electric. In Norway, this is well over fifty percent. It is not just the price that makes a car buyer hesitate. The driving range plays a role, the availability of charging stations, the effect that temperature has on the performance of the battery. Or the stressed feeling that is called ‘range anxiety’: will I come to a standstill because my battery is empty?

Workhorse

The battery, in fact, is the critical factor for switching to fully electric driving. It seems to lag behind all other technology that is in the car. The first commercial lithium-ion batteries were introduced in the nineties. The 2019 Nobel Prize for chemistry went to Yoshino, Goodenough and Whittinghan, for inventing it. Lithium-ion batteries will certainly be the workhorses in the years to come, says UT professor Mark Huijben: ‘It has the advantage of a high energy density. There’s not really a better alternative for that. Improvements are possible, though, by choosing other approaches for the positive and negative terminals of the battery, the cathode and anode. The charging speed can be improved, for example.’

Huijben is one of the founders and leaders of the recently started Twente Centre for Advanced Battery Technology (TCABT), in which the University of Twente concentrates its battery research. Huijben’s own field of work is about developing new nanomaterials. The battery’s anode, for example, is now made of graphite. Instead, the scientist is experimenting with niobium-tungsten-oxide. By structuring this material with tiny nanochannels, the battery can be charged faster. ‘Silicon is an option as well, this can hold ten times more lithium. A disadvantage is that it is swelling and shrinking when charged particles pass by. By introducing silicon as nanoparticles, we can take away this disadvantage.’

Solid-state

The decisive breakthrough everybody seems to wait for, is a solid-state battery. Now, the battery dielectric, between the anode and the cathode, is still a liquid. This can be risky, for example if the battery gets damaged or if it is charged in the wrong way. Huijben is convinced that the future is all about batteries with a solid dielectric: ‘Just look at the amount of research that is currently done on this, worldwide.’ So far, we understood that improvements of the anode are possible, there will be a better dielectric that is still based on lithium, but solid instead of liquid; what about ‘the other side’, the cathode? For a battery that performs well, still a specific material is needed that, in fact, severely harms the battery’s reputation of sustainability. That material is cobalt. ‘The latest lithium-ion batteries have a reduced amount of cobalt, but we still need it,’ Huyben says. The founder of Tesla, Elon Musk has announced that future generations of his electric cars will be free of cobalt.

Lithium mine in Atacama, Chili (photo ANP/HH) 

Raw materials

What is actually the problem with cobalt, is explained by Arjan Dijkstra, who is with the UT Faculty of Geoinformation Science and Earth Observation (ITC). ‘It is one of the so-called ‘conflict materials’. Most of it comes from the Democratic Republic of Congo, as a by-product of nickel and iron. Mining is risky work, often done by children. There aren’t that many alternatives. You could think of deep sea mining as cobalt is also in so-called manganese nodules. But that is another type of mining that is controversial.’

Talking about the materials of a battery, what about lithium? We’ll need huge and ever growing amounts of this. Dijkstra: ‘Lithium is not scarce. There are several ways of mining it; we know the rock mines in Australia, but also the large salt plains, salars, in South America. There, lithium remains after evaporating water and getting the salt out. The local people protest against it, because they say the mining activities extract water from their living environment. Bolivia, for that reason, having the largest salt plains in the world, is already more reluctant in allowing lithium mining. At ITC, we do research on the actual effect of mining on the water resources. What we also can do, using satellite images and remote sensing, is discover new sources of lithium. In fact, we can also use similar advanced imaging techniques to get lithium out of a waste stream. Don’t forget that there is another way of satisfying our ‘lithium hunger’. That is recycling. And it’s hardly done at all, at this moment.’

 'There is another way of satisfying our ‘lithium hunger’'

What is done instead, is giving batteries a second life. An example is the Johan Cruyff Arena soccer stadium in Amsterdam that stores electric energy using hundreds of discarded car batteries. The performance of this huge battery pack, however, will go down over time as well.

Green and smart production

Making the step from raw and engineered materials towards actual manufacturing of batteries, we meet Professor Sebastian Thiede, who is one of the leaders of TCABT together with Mark Huijben. ‘A lot of energy and material is still needed to produce a battery at this point. Producing an electric car has, in terms of CO2 emission and energy consumption, quite some more impact than producing a car that is powered by fossil fuels. My ambition is making this process more energy and cost efficient. Producing a single battery cell that will be part of a larger pack or module, involves steps like mixing the chemicals, coating, drying and producing the sheets of material that will be part of the cell. Standardizing this to a larger extent makes sense, resulting in battery cells, modules and packs that can be used in several applications.’

 ‘A lot of energy and material is still needed to produce a battery' 

European plants

One of the factors in the process that consumes a lot of energy, is the need for a ‘dry chamber’: extremely dry production surroundings. This is because the battery compounds, especially lithium, don’t like water and could react violently. Thiede would like to find out if it is possible to accelerate the process, so the time spent in the dry chamber is as short as possible. New ‘Industry 4.0’ insights, using digitization and artificial intelligence, may help. He shares Dijkstra’s opinion about the potential of recycling the materials. ‘We can get far more lithium out of used batteries using process technology’. Economically speaking, this is not very interesting yet. But it is also clear that the battery, as a major enabler of the energy transition, should be circular. For Thiede, it is essential that battery innovations are shared and applied across Europe. ‘Within TCABT, we also look at the geopolitics of battery development. Right now, we simply are too dependent on companies in Asia for the whole production chain. That is not a healthy situation.’ European car manufacturers are now investing billions of euros in battery production plants in Europe.

User preferences

And then, the battery is ready to be mounted inside a car. From that moment on, it seems simple: charge it and drive, just like filling the tank with fossil fuels. This, however, can be done smarter as well. The future car battery will play an active role in the sustainable energy mix: in this perspective, a car can be seen as a mobile energy storage unit that can deliver its electrical energy as well. At moments, for example, that there is an energy demand at home while the sustainable sources like sun and wind are not delivering sufficient power, the car battery helps out. It is clear that balancing this, requires a very intelligent planning system. UT’s knowledge of artificial intelligence and power electronics will help. But there is a behavioural side to it as well: the moment a user needs his car, while the battery is almost discharged for other purposes, he will not take this ‘intelligent system’ for granted or overrule it the next time. Of course, there is a technical solution that may avoid this, like having a spare battery pack at home. But the need of including user behaviour in TCABT’s research is clear. Even looking at the popularity of electric driving in Norway, these human factors play a role. Reduced ferry fares and the permission to use bus lanes with your electric car, show that incentives that have nothing to do with technology, work.