BASF’s head of chemicals research and engineering Dr Andreas Fischer
How BASF will deliver better batteries for hybrids and electric vehicles
- Published in Q&A.
Dr Andreas Fischer: It’s R&D now but in 10-20 years you could see rechargeable lithium-air batteries
You’re working on lithium-sulphur technology that would replace lithium-ion in the future – what are the advantages?
“Sulphur is a lightweight material compared to metals so gravimetric energy density is higher. If you take volumetric energy density, the advantage is not so great, and that’s a bit of an issue in today’s cars, but won’t be so relevant in the future because this type of battery won’t reach the market for 10-20 years. Today OEMs are looking for volumetric energy density – watt-hours per litre – because they have limited space in vehicles designed for combustion engines. In the future, cars will be more adapted to battery systems and so more space will be available. So then weight will be a more important issue than volume.
The lithium-sulphur chemistry you’re working on doesn’t use any cobalt or manganese: how will cost compare to lithium-ion?
“Sulphur is a very cheap material compared to cobalt, manganese and nickel. And in the long run you won’t talk about cost per kilogram but you will talk about cost per kilowatt-hour. And, if you can deliver more energy, cost will go down.
Calendar life can be a problem for lithium-ion batteries: will this apply to lithium-sulphur too?
“It’s more of an issue with lithium-ion at the moment but it’s a challenge and we’re working on improving cycle life as well as calendar life.
Beyond lithium-sulphur, BASF is also looking at lithium-air: what’s the status of this technology?
“For the moment, it’s R&D technology. I won’t say that it will stay that way forever but there are even more problems related to lithium-air batteries than for lithium-sulphur batteries so we’ve decided to focus on the latter for the mid-term. We’re trying to figure out how far we can get with lithium-air. There are difficulties with the electrocatalysts – they have a very low efficiency. In other chemistries, we achieve almost 100%, but for lithium-air it’s more like 50% or 60%. So this has to be improved a lot. Our next problem is the lithium because the air in the battery could lead to oxidation. You also have problems with the humidity in the air. So it’s a very tough challenge and we have to see if it can be made to happen. It’s R&D now but in 10-20 years you could see rechargeable lithium-air batteries.
Impurities in electrode materials can affect battery performance but how significant is the issue?
“They have a severe impact. Our customers are very much concerned with quality and repeatability and that they always get the same material with the same content.
There’s a lot of focus on cathode materials but how much potential for battery performance improvement is there in electrolytes?
“This is a complex question because you have to look at the whole system. It’s not so much that you say, OK, if I develop a new electrolyte it will double energy density. It’s more that you need to have an appropriate electrolyte for your system – it has to work with the cathode and anode materials. The electrolyte enables the rest of the materials to deliver their potential.
What’s really going to deliver the improvements in battery technology the automotive industry needs?
“There have to be improvements everywhere – battery manufacturing, cell manufacturing but also materials. So it’s really the whole system chain in order to bring the costs down. For consumer goods, where you have mass production, battery costs are very low, and this will also happen for vehicles too. Then improvements in materials and energy density will come when process costs are brought to the absolute minimum.
There’s a lot of hype surrounding electromobility, and estimates on the number of electric vehicles on the road by 2020 vary considerably: does this affect R&D?
“For sure, it’s an emerging technology and a lot of problems aren’t solved yet. But there are government programmes already and we are quite convinced that this will become a mass market – there’s already quite a big market for hybrids. There’s certainly a bit of hype at the moment because everybody is talking about it but, on the other hand, it’s very important to drive this technology forwards. And very important for the European automotive industry because the Chinese and the Americans are developing fast. There’s a lot going on at the moment and it’s exciting. I can’t tell how many electric vehicles will be on the street in 10 years but I’d guess it’ll be a lot.
