Next development step
According to Poul Norby, the next step in the development of new batteries is solid-state batteries. Unlike in current lithium-ion batteries, the electrolyte (i.e., the connection between the positive and negative poles of the battery) is solid instead of liquid and is made of glass, minerals or polymers.
Several major car manufacturers have invested heavily in the development of solid-state batteries, which are expected to be more fireproof, charge significantly faster, and contain twice as much energy as the lithium-ion batteries available today. Several car brands have announced that they expect to have a usable solid-state battery ready by 2025.
According to Poul Norby, the ultimate dream is to have a lithium-air battery with an energy density close to that of fossil fuels—and which does not require cobalt:
“The benefits of developing a lithium-air battery have always been massive but getting there is incredibly difficult. If not for the huge benefits we stand to gain, no one would ever attempt it.”
By combining calculations with experimental work, DTU researchers have shown that—in theory—it is possible to make a lithium-air battery. However, it is so far proving very difficult to achieve sufficient energy efficiency, charging speed, and durability.
“This is definitely something that could revolutionize battery technology, but it’s a long way off, if it’s even possible,” he says.
New life for old batteries
Recirculation will also play an important part in preventing a shortage of raw materials in the long run. The aforementioned KU Leuven study estimates that if Europe invests heavily now, the continent will be able to cover 40-75 per cent of the need for raw materials for the green transition through recycling alone.
“The public debate leaves the impression that recirculation starts here and now, but that’s not true. Battery materials have been recycled for a very long time. It’s been difficult and expensive so far, but the development of cheaper and more efficient recycling methods is moving fast,” says Poul Norby.
Figures from the European Parliament show that in 2019, 51 per cent of portable batteries sold in the EU were collected for recycling, but EU politicians are working to adjust the rules to ensure a higher level of recycling, including of batteries from storage and electric cars.
“Virtually all materials in batteries will have to be recycled in the future—even if it’s not profitable,” says Professor Norby.
Tesla and Volkswagen report that they can already recycle more than 90 per cent of the materials in their own batteries. Of course the recycling process is undeniably easier when it comes to disassembling 500 kg batteries and sorting them into piles of usable raw materials than when handling a mixture of smaller batteries from, e.g., mobile phones and laptops, which contain different types of metals in varying amounts.
“Now we’ll get these big batteries where you know exactly what’s in them, how they’ve been treated, and what they’re made of. That also makes it a lot easier to take them apart,” says Poul Norby.
There are also other ways to think about recirculation of electric car batteries: When the charging capacity becomes too poor for the batteries to be used in cars, they can be used for other things such as storing power in small, local solar cell plants. A stack of used batteries can form a local storage unit for 10-15 years before it is necessary to take the batteries apart and use the raw materials again.
By prolonging the life of the batteries in this way, we can also buy time for the development of cheaper and better ways to recycle the raw materials