A tough one

A talk with Professor Martin Winter

Electric mobility is speeding up. How are things with the heart of the electric vehicle: the battery? Where does the research stand, what is the future of the technology, what are its prospects? A talk with chemist and materials researcher Professor Martin Winter, head of the Münster Electrochemical Energy Technology (MEET) center at the University of Münster.

Mr. Winter, Germany is the cradle of the combustion engine. Does that make it a tough place for battery research?

Prof. Winter: Germany has worked hard to once more become a leader in battery research. Just look at MEET, which has a respectable ranking in international comparisons. About 140 colleagues work at the institute that was established in 2011. This work has generated more than 300 projects and 45 patent applications. However, you need to realize that Germany is not a pioneer in bringing the technology to the market.  Asia is the leader and massive amounts of money are being invested in battery technologies and their market launch.

One often hears that German industry is being left behind. How do you see things?

German companies need to offer electric vehicles in countries where the future of electro mobility is clear, and the general conditions are attractive. Here in Germany, getting an electric vehicle quickly can be difficult. Delivery times are up to 18 months. Demand is high - even in Germany. The supply is simply too low.

Professor Martin Winter
 

But that is not the largest hurdle. What are the biggest challenges that most shape your research?

The battery costs, they are the biggest problem from the users’ perspective. We are currently at a price level of more than 100 euros per kilowatt hour in a cell. 

How can your institute help lower costs?

We cannot influence raw material prices but can reduce the share of raw materials or find substitutes for those that are particularly costly. The difficultly is in maintaining factors such as the current performance parameters or the minimum safety levels. We are also researching how to extend battery life, which also helps lower battery costs. Over the long term, we are looking at new process steps for recycling to lower material costs.

Many see range as the greatest obstacle. Is there any hope to seriously compete against the combustion engine?

I do not think that should be the goal at all, as the various drive types will co-exist for decades. Things might stay that way, for example, heavy freight transport may use combustion engines or fuel cells as a generator and a battery for the power train. Range is not really an issue for most of us today, because our trips are short enough for an electric vehicle.

Nevertheless, you continue to work on range extension. What can we expect?

Range is physically limited. Nowadays, we researchers assume a maximum range of two kilometers for each kilogram of battery, which would be a range of 600 km for the typical battery weight of 300 kg in use today. Right now, we get about 700 meters per kilogram. So, there is enormous development potential within the next ten years.

A few years ago, people were saying that new battery types would completely end the range discussion.

I have always said that lithium-ion technology would be with us for a long time. I have been proven right. I think other battery forms such as the lithium/air battery will not be used within the next 15 years.

Why?

We talk about the five challenges to battery development: 1st energy, or range, 2nd performance, 3rd safety, 4th cost and 5th service life. Progress in one area tends to have a negative impact on at least one of the other areas. So, having a battery type that only improves range but significantly compromises the other four properties does not help at all. The lithium-ion battery is the closest thing to an all-rounder. However, things may change.

What will battery research cook up next?

Right now, three research trends are of equal importance. The first group focuses on continued improvements to lithium-ion batteries, particularly to the costs as already mentioned. Range and charging speed come next on the agenda. The focus for the second group is improving the range of future battery types, without sacrificing the benefits of lithium-ion batteries. Experiments are being made here with lithium metal anodes, which are strongly linked to solid-state batteries. It is something for after 2025.

And the third research trend?

Work on batteries without lithium. Right now, nothing functions better than the current energy storage material. However, if raw material prices continue to rise, they might find an affordable alternative for certain applications, such as smaller photovoltaic systems. Research is being carried out into zinc/air, sodium ion and magnesium batteries. The trend right now also tends toward calcium, but that is far into the future, as are aluminum batteries. We are still doing fundamental research.

Which candidates do you see presenting the biggest opportunities?

Sodium-ion batteries have made enormous progress in the past few years. Not just lithium but other expensive materials such as copper and cobalt are important to lithium-ion batteries but not sodium-ion batteries. When the sodium-ion battery is more performant and is truly cheaper than lithium-ion technology, it will have a real chance.

When will e-mobility take off?

We think it can start now. In principle, the batteries are complete. I do not mean that they are developed to perfection but are ready for use in the coming years. The disadvantages of combustion engines were made painfully obvious in the diesel crisis. We want cleaner cities. So, we need to use electric motors and hybrid drives...

..., which do not have a significantly better ecological balance sheet with the current electricity mix.

But the pollution problems will ease for the cities and their surroundings. Of course, the transportation shift will have to involve the massive expansion of green energy; they need to run in parallel. This is not just true for generating charging energy but also for energy-intensive battery production. We need to come to grips with the subject, without assuming everything will change at once. The combustion engine will be supplemented at first. At the same time, we will move forward with other developments. Experiment, improve, expand - this is what we want. Only then can hurdles be overcome. And I am sure we will succeed!