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Professor Martin Winter, who is a chemist, heads the Helmholtz Institute Münster and the MEET Battery Research Center at the Westfälische Wilhelms-Universität Münster. In the interview he talks about the current challenges in battery technology.
© Judith Kraft, WWU/MEET
Battery researcher Martin Winter in interview
14.03.2017

"One million electric cars are feasible by 2025"

Expensive, short ranges and long charging times: Today's batteries for electric vehicles have a negative image. However, the electric car is actually ready for series production. Well at least almost. In the BINE interview, Professor Martin Winter from the MEET Battery Research Center at Westfälische Wilhelms-Universität Münster and the Helmholtz Institute Münster talks about the hurdles that still need to be overcome and how it will be possible to get considerably more electric vehicles onto the streets in the coming years.

BINE Information Service: Professor Winter, electric vehicles with battery drives are still struggling with many prejudices: they are expensive, the range is low, the charging times take too long and the batteries fail too quickly. Is this true or not?

Professor Martin Winter: Yes and no. In mobility, we can still expect considerable progress. Combustion vehicles are also far from reaching their development maturity. In comparison, electric vehicles are still at an early stage of their development – there is still considerable scope for improvements. Nevertheless, the progress we have made over the past four to five years is tremendous – especially in terms of reliability, safety and service life. And we are increasingly getting control over the costs and range. We could never have previously imagined these enormous advances. I'm very optimistic that the improved electric vehicles in future will also convince the doubters.

How can the current problems – such as the infrastructure and charging times – be solved?

Winter: The range is physically determined. We're comparing apples with pears, since with the battery we have two reacting agents on board, which we have to keep recharging and discharging. The internal combustion engine, on the other hand, only has one reacting agent in the vehicle, the liquid fuel, which operates according to a one-way mechanism. The other reacting agent, air-oxygen, is only temporarily in the engine, so it is not only cost-effective but also weight-effective. However, it pollutes the environment through the exhaust gases, such as carbon dioxide and nitrogen oxide, which result from the combustion.

The costs can still drop significantly. Since we have now reached about 150 euros per kilowatt-hour at the cell level, we can expect significantly less than 100 euros per kilowatt-hour in ten years. Then a battery car would be comparable to a really low-emission combustion vehicle. One unknown factor, however, still remains: the raw material costs that could upset the calculations – since the earth's resources are finite.

Future of electromobility

We are currently talking about purely battery powered vehicles. But where's the journey taking us? More towards battery-driven or more towards fuel cell-driven vehicles?

Winter: Batteries and fuel cells cannot be compared against one another because they are complementary in many aspects. This starts with the hybridisation: it has been found that lithium-ion technology is particularly very dynamic – and this for a relatively wide charge range, both at a low charging state and when almost fully charged. It is also very dynamic when accelerating and charging, in other words during the regenerative braking. No other storage technology can do this so well. In a vehicle with a fuel cell, you need a battery to ensure the dynamics – for the acceleration, regenerative braking and the like. Today's range-extender vehicles have batteries with an internal combustion engine on board; the internal combustion engine increases the range of the battery. In future range-extenders, the internal combustion engine can be replaced by a fuel cell. The fuel cell has the advantage at the moment that it can be fuelled even faster than the battery.

Whether we combine a large battery with a small fuel cell or a large fuel cell with a small battery will depend, among other things, on the range we can achieve with the battery and how cheap the fuel cell can still become.

Batteries currently work just fine and there is an established mass production. It is certainly not yet possible to determine whether fuel cells will actually become the "better battery"; perhaps this will never be determined. At least at the moment there's no reason why there can't be a synergetic coexistence of both technologies; side by side and together they are strong.

Fuel cell and battery in one car: How will we be travelling in the next 10 to 20 years?

Winter: This is quite difficult to say, because the issue is not only technology-dependent, but also politically and emissions-driven, in particular CO2- and particle emissions-driven. If we comply with the CO2 targets without ifs and buts, electromobility will quickly conquer the market. Indeed, ambitious targets are always being formulated with regard to reducing CO2 – however for periods in the distant future. Whether and how these plans are maintained is another question. We have only recently learned that the measurement of exhaust gases is quite error-prone. There will certainly be a transitional period in which combustion engines and electric vehicles will be running side by side. If we fail to adhere to the CO2 limits or rigorously ensure their compliance, the transitional period will take a long time, certainly 10 to 20 years, and will also be shaped for a long time by combustion vehicles. This scenario has many advocates in Germany, especially in the automotive industry.

"One million electric cars by 2020 was always an ambitious goal"

The German federal government's declared goal of getting one million electric vehicles on the German roads by 2020 still seems a remote possibility. In 2016 there were just 11,500 electric cars and 48,000 hybrid cars. What do the government, industry and research still need to do to change that?

Winter: Industry often argues that the market and not legislation should determine whether electromobility is accepted. This would consequently mean that we would give less priority to the statutory provisions for CO2 benchmarks. On the other hand, experience shows that legal regulations indeed influence buying behaviour. In the meantime, you can no longer drive into German cities with a car with a yellow emission sticker. The car buyers responded accordingly. In future the green emission sticker will also not be enough, which will undoubtedly influence buying behaviour. The issue of particulate matter particles and their effect on the human body is currently attracting considerable media attention. What would happen if residents who have fallen ill begin to sue the cities because driving bans are not declared or controlled? Until now we have been in the "can" situation, in which we were able to decide ourselves. We are now entering the "must" phase: we have to keep the cities cleaner because the fine dust pollution of the air, which has always been there, has become an issue that we can no longer ignore.

And what does this mean in terms of cells and cars?

Winter: The German automotive industry assumes that there will be several dozen models. But these are envisaged for the future. If you want to buy an electric car today, many manufacturers provide only one model. All other products are hybrids. There is a lack of products and, in addition, people cannot reliably charge up. There are not enough public charging stations. And the charging takes time.
In general, however, it must also be said that we have only had really good battery cells for a few years. This may surprise many, because the batteries have looked similar for years, but it depends on the content. By way of comparison: We now use USB flash drives that look identical to those we used ten years ago. However, the current ones now have several gigabytes and not just a few megabytes. The same has happened with the batteries. They have the same battery designs as 20 years ago, but now they have three to four times as much battery power for the same volume.

Ultimately, the material costs cannot be reduced indefinitely. Because there is a finite availability of materials and these are individually different. As a whole, there have therefore been and continue to be many uncertainties, so one million electric cars have always been an ambitious target by 2020. However, from today's point of view I think this is certainly feasible by 2025. In general, I would hope that we are moving from the rather passive, wait-and-see attitude to the active fostering of electromobility. Instead of announcing and reacting, we need to lead and deliver the development.

What's the situation with other applications?

Winter: For batteries, there are significantly more applications than just electric vehicles, such as portable electronics, storing renewable energies or aviation. The lithium-ion technology has a very high energy density per volume, but in weight terms there are probably better alternatives. And if the batteries are too heavy, the airplanes will not take off. However, it's not too difficult to create more space in aviation.

For entertainment electronics, on the other hand, that's a no-go – because everyone wants to have a thin mobile phone. No one cares at all whether it weighs 10 grams or more. But if it is three centimetres thick instead of half a centimetre: Who wants to carry a brick in his pocket? The same is true for cars. People would prefer them to weigh a few kilos more than to compromise on passenger space.

You have referred to the availability of the raw materials. Does this concern lithium or other materials?

Winter: Lithium is a comparatively common element. Cobalt and nickel are much rarer, especially the availability of cobalt is causing headaches. The problem with lithium is that its production cannot be scaled up so quickly. Whenever the demand increases – whereby speculation also plays a role – there are therefore price increases. A slow start to electromobility is therefore actually quite good for the price development of the batteries.

You have co-authored the new BINE-Themeninfo brochure on "Electromobility". What is personally dear to your heart in the debate about batteries and fuel cells?

Winter: I come from the lithium-ion technology area. The lithium-ion battery was introduced to the market when I began scientific research on the subject – at that time I was still working on my undergraduate thesis. And somehow the love remains with what you have learned, with what you have grown up with. Although I am a real battery enthusiast and batteries are currently nosing ahead in terms of their applications, I would be reluctant to see fuel cells not get the attention they undoubtedly deserve.

I am a huge fan of keeping track of technologies in parallel, comparing them critically and also revealing the strengths and weaknesses of the technologies. As a spokesperson for German battery research, I would like to say to all those working in the research and development of electrochemical energy storage systems and converters: Be critical about your own work and data! Particularly today, as we await the breakthrough of new drive technologies, efforts are made to assess the results in a positive light and to blend out the disadvantages. This is generally not good for the technology itself and the credibility of the researchers and developers. Excellent results and successes for batteries and fuel cells will speak for themselves and I am convinced that we will see many of them.

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In interview

Professor Martin Winter has been working in the field of electrochemical energy storage and energy conversion for more than 25 years. His research focus is on lithium-ion batteries and supercapacitors. Winter is the founding director of the Helmholtz Institute Münster, which belongs to Research Center Jülich, is professor at the Westfälische Wilhelms-Universität Münster and is also the founder and head of the university's MEET Battery Research Center.