By Niels Landbo Krogh, AAU Communication & Public Affairs

Erik Schaltz is an associate professor at AAU ENERGY and started his career with a PhD in fuel cells for cars. Over the past 20 years, he has built expertise in e-mobility, the study of electric cars and their batteries.

His work includes stress-testing batteries by exposing them to extreme heat, cold, different charge levels, and many charge and discharge cycles. The development in e-mobility has never been faster, and Erik Schaltz's research is receiving great attention at a time when Denmark is increasingly running on batteries. For example, for the first time this year, all finalists for Car of the Year 2025 are electric cars.

We asked Erik Schaltz a series of questions about his research field, battery research in Denmark and Europe, and how he came to research batteries and electric cars.

How do you determine a battery's lifespan?

"It is difficult to answer precisely, and the length will always be a prediction. It is hard to verify fixed models because batteries are exposed to different conditions and usage patterns during their lifespan."

In his laboratory, Erik Schaltz conducts accelerated tests, where he subjects batteries to stress loads such as high and low temperatures, different charge levels, and many charge and discharge cycles. All of this affects the product's lifespan.

Batteries have become very durable and efficient, Schaltz explains.

"There is widespread skepticism about their quality, but it is exaggerated because we see that typical electric car batteries work well and only lose strength after many years of use. This is a positive thing, and I hope that assumption will soon be a thing of the past."

New Types of Batteries

The newest battery cells are hidden in the laboratories of the major car giants, but Erik Schaltz keeps up with the published data on where the technology is heading.

"The new solid-state batteries are very promising, and they will most likely become widespread within a few years. They will have a much larger capacity. In laboratory measurements at car manufacturers, they see about a doubling of the battery's capacity compared to now."

Erik Schaltz predicts that parallel technologies will make batteries both stronger and cheaper:

"The iron phosphate battery, which we see from, for example, Chinese BYD, has a long cycle life and is much cheaper. However, they have a lower energy density so far, so there is not as much power in the battery as solid-state. Iron phosphate batteries have become so good that they can easily be used for mid-range electric cars."

Problems with Lithium and Cobalt

Tesla was the first manufacturer to make a good usable electric car, Schaltz explains, and Tesla did it "by connecting a lot of laptop batteries in a completely new way," says the associate professor:

"They are still cylindrical cells, which are small and easy to handle thermally, but it is not a super-efficient way to pack the battery."

The new Chinese Blade technology from BYD is worth keeping an eye on here, the AAU researcher says, because here all cells are placed together in one package, and there can be more energy in one place. Sodium-ion batteries will also become a big thing because sodium is more widespread in the world and a less problematic material to extract than, for example, cobalt, which has been extracted under questionable conditions in war-torn Congo. And lithium extraction requires a lot of water.

How has e-mobility developed during the time you have worked with the subject?

"I started researching the use of hydrogen and fuel cells for vehicles in 2005. Back then, many hoped for hydrogen because it was easily comparable to petrol cars in range and refueling time, and back then, battery cars were much less usable."

Easy to Have an Electric Car Today

This year, all finalist cars for the Car of the Year 2025 nomination are electric cars, and transportation is being electrified on a large scale.

"It has also become easier to be an electric car user. Practically speaking, the charging plug used to be a bit of a mess, and what should you bet on? CCS (Combined Charging System) is now the prevailing standard in Europe along with Tesla's plug, and people can understand that."

You are part of the Danish Battery Society. What do you work on?

"In the Danish Battery Society, we host events and share professional knowledge across universities and with the manufacturers who are part of the battery value chain, such as Danish Topsoe and Lithium Balance."

Danish Battery Research

Erik Schaltz explains that battery researchers in Denmark work with both the application aspect and material science to develop new and better batteries.

"We are good in Denmark at making models for the lifespan and use of batteries and studying how to extend their lifespan. It is not as easy as one might think, and certainly not as simple as the technology that measures how full a petrol car is with fuel."