Automotive Engineer

OEMs have a lot of demands on Li-ion battery technology. What are the most important?
For OEMs safety is a simple must; they expect a EUCAR safety level 4 or better. There are clear targets on cost and power and energy density. It is expected that something between 130 and 150Wh/kg can be achieved by 2013/14.

Li-ion is relatively immature in automotive applications. How much work lies ahead?
There’s still a lot to be done, especially when you look at consumer cells. They have quite good energy density already – they’ve reached about 250Wh/kg, with the best up to 280 – but they are only specified up to around 500 charge/discharge cycles over a lifetime of around three years. After 500 cycles they reach about 50% capacity. In the automotive industry you expect 10 years at least and about 2-3,000 cycles and 80% capacity at end-of-life. That’s a big difference.

China is heavily subsiding EVs – what effect do you think this will have on the market there?
It’s about €6-7,000 plus another subsidy from the state – this will help but just comparing the costs, it will not be a breakthrough. The breakthrough I would expect in China is more to do with the question of whether there will be restricted access to big cities for cars with internal combustion engines. This will be much more influential to EVs’ proliferation. I think China is preparing for that.

How will the growth of electromobility affect lithium supply and cost?
Around 10% of a Li-ion battery’s cost is raw material, of which the smallest part is lithium. Lithium is about 5% of battery’s weight. Lithium is not a limiting resource. It is frequently reported in newspapers that lithium is the new oil and that South America will become the new OPEC, but that’s simply wrong. A salt lake was discovered in Bolivia three years ago, but it's not needed. The resources coming from Chile easily cover the world markets.
There is one important resource at a low-level, which is not widely available worldwide, and that’s cobalt. The standard automotive cathode technology is NCM: nickel-cobalt-managanese. Nickel is expensive but not limited. Cobalt could be a limiting factor if we were to reach 100 million vehicles a year, all equipped with 20kWh batteries – it would only take some 10 years to exhaust available global resources. There are only three places you can get cobalt from, but the good news is that we’ll remove it from old batteries so this will no longer be a problem.

You expect Li-ion to reach €350/kWh by 2015, falling again to €250/kWh by 2020. What’s going to deliver these cost reductions?
Mass-production will have the biggest impact because of economies of scale and standardisation. If you look at consumer cells, the price per kWh from the so-called 18650 cells used in laptops is about $200-250/kWh. This makes it clear that the target of €250/kWh by 2020 is achievable, even if we have more severe requirements for lifetime and cycle ageing.
But taking into account what we’ve seen in consumer cells – a doubling of energy content within the last 10 years and the price dropping to a third per kWh – it’s clear what mass-production leads to. Each year about 2 billion of these 18650 cells are made worldwide.