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When we last saw Lennart Stegland, head of electric car development for Volvo, we were down in snowy Indianapolis and he was announcing a newly-minted deal to develop lithium-ion batteries with Enerdel. Eleven months later in Detroit, the frigid conditions are the same but development of the C30 BEV has made serious progress. We sat down with him next to a wrecked example of his handiwork at the 2011 North American International Auto Show to talk electric car safety.
Tell us why you’re proud of the C30 electric car.
– Well I think our theme is obvious. We’re the only ones talking about safety in connection with electric cars. The message is clear and it’s that we are clear on our way of approaching battery technology. Things like lithium-ion technology, you need to take care of it, otherwise there can be some irregularities you wouldn’t like to have. Having that in mind, any car we put to market must fulfill all expectations we have in terms of crashworthiness. The conclusion is to put the batteries in the car where they are not exposed to crumple zones. As soon as you start to compress battery cells, well, they don’t like it. We’ve placed them such that if any compression starts, the crash is so violent you’ve likely met your creator anyway. We’re proud of that.
Tell us about the crashed car on display at the 2011 Detroit show.
-Well, this car has been crashed in an offset collision at 64 kph (40 mph) and that is a pretty violent crash. In a normal car, a big part of the mass is the combustion engine at the front and you start to engage that in the crash sequence, but here the mass is positioned further back. More energy, then, is taken by the beam structure. That means we modified the crash structure both under the hood and around the batteries. In all car, we have a side impact system that uses the central tunnel to absorb energy, but here, that’s where the battery lives. Now we have to make that part ultra safe, moving the energy out. So the sides of the car, they are extraordinarily stiff. There are also bulkheads inside the batteries that add stiffness.
So does that mean you’ve worked with Enerdel (Volvo’s battery supplier) to make the batteries themselves more crashworthy?
-The battery design, everything you see is very much a cooperation between Volvo and Enerdel. They of course deal with the cells, the battery management, but we have to help integrate them into the car and the crash structure.
Has that been a good partnership?
-Oh, absolutely. Absolutely.
The Detroit show stand car shows a front collision. Are rear accidents more dangerous because one battery pack sits under the cargo floor?
-No, there’s a very strong structure there as well and we have crashed cars in the rear, of course. We’ve done the full program, including side and rear impacts, to our usual standards. It must be acceptable to the levels of other Volvos.
Leaving the safety aspect for a moment, can you tell us about the challenge of heating the car in colder climates?
-Well, the biggest question when it comes to electric vehicles is the idea of range anxiety. It’s either there or it isn’t, and after a few weeks with the car, one gets used to it and the anxiety is no longer an issue. But until that point, it’s a serious psychological barrier. So when we talk about the energy inside the batteries, we want to use that for mobility as much as we can. There are two issues here. One is our pre-programmed auto-start, where you are pre-conditioning the car while it is still on a charger. When you go to it in the morning, it is already ready for the exterior temperature, so you already start at a certain comfort level. But there’s a difference between bringing a car to that level and maintaining it.
After the car is running, if it is cold outside, we have a fuel-operated heated. That delivers almost six kilowatts, enough for most conditions to fill our demands in Scandinavia. That should save a significant amount of electrical energy. If you’re operating at -10 degrees Celsius (14 degrees F) I would say that the car would use 30-40 percent of the battery energy just to heat the cabin.
How do governmental organizations view a gas heater in terms of fuel economy ratings? Is this no longer considered an electric car?
-The good thing is that certification takes place at a normal room temperature, so the heater does not come into play (laughs.) But is an interesting subject. We are using ethanol for the fuel, so by using a biofuel we can say that the impact is quite low. The use of biofuel means customers can stay warm but still walk away with a good conscience.
Tell us about the cars already on the road.
-We have about 20 cars now in Sweden and we are building a second series now of ten cars and will head into serious production just before summer when we will quickly distribute about 250 cars in the Swedish market. After that we must look into the European and US markets.
Has anything about the test fleet surprised you?
-Yes, we can say that it is not a piece of cake to make an electric vehicle. We are influencing so many systems by adding the electric components and the subsequent development is huge to make the car work like a normal car. That is what we will give to the customer, it must be a normal car. What we see now is that there is huge complexity here, huge complexity when it comes to reliability. There are new sensors, new stuff that has never been in a volume automobile. In quality assurance, this is where we see issues. But we are tackling those issues and will take control of them, even if we are not 100 percent there. We have been humbled by the task but we will do it, we will get there and have a very nice car.
What’s the next big goal now that the safety has been proved?
-It’s really fine-tuning at this point. We must look at the start sequence, how to use the power grid in the most energy-efficient way possible. We have to learn more about optimizing those processes. We would like to look at insulation in a more efficient way. We’ve already prepared the car with special glass to take down the thermal load when it is hot, but there are other measures that can be taken as well. It’s a constant battle.
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