So my question is, What is the cost of these new 500 wh/kg batteries in the near term, and what is a realistic estimate of their cost if they were manufactured in large scale?
Good question!
The
US advanced battery consortium (USABC), who are the authorities on this matter, have decided that EVs will finally be able to compete directly with fossil fuel powered cars on price once battery energy storage has fallen to around
$150 per kilowatt-hour (kWh). I’ve run these sums too, and I think that they’re actually being a bit optimistic with this figure, and the point at which EVs will really be price competetive with fossil-fuelled autos is more likely to be around
$80 per kilowatt-hour. At this price, for example, a 200 mile range pack would cost around $3,200 and could easily outlast the life of the car itself at 1,000 cycles.
But the question is not really
if this price level can be reached, it’s more a question of when. They say that the past is no guide to future performance, but I’m still a bit of a sucker for keeping an eye on trends in the same way that computer scientists like to keep tabs on Moore’s law. As an example, the chart I’ve made below shows (roughly) how lithium-ion battery storage costs have fallen over the last 10 years or so since they were introduced in the early nineties.
You can see that the price of todays cheapest LiIon storage is around $300 per kWh. This is approximately the price you can expect to pay by making a big battery from AA cells, as pioneered by
AC propulsion, or by buying larger packs directly from
Thundersky, a company specialising in Lithium batteries for electric vehicles.
However, if you project the same trend of the last ten years into the coming years, LiIon should achieve the USABCs mid-term aim of
$150/kWh by around 2007,
$80/kWh by 2010 and around
$55/kWh by 2012. (See chart below).
How can I be so sure that the price of LiIon will continue to plummet so dramatically? For two reasons. Firstly, energy density is increasing at an almost predictable annual rate. Todays LG-Chem 18650s
(as used by AC Propulsion) are at around 170Wh/kg. But more than a year ago, cells in development at
Polyplus were running at
420Wh/kg and presumably need only be ruggedised before commercialisation (OK, no easy feat, but once achieved would be an enormous step forward!).
The second even BIGGER influence on LiIon cost is the fact that the market for it just keeps expanding, bringing all the advantages of larger scale manufacturing and intense competition. Ironically, these plummeting costs in battery storage which are of such obvious benefit to EVs are not being driven by the automotive industry at all – the pressure is coming entirely from the ever increasing demand for lighter and longer lasting consumer electronics!
Another way to look at it is to consider battery technologies which are already mature in large volume. Take Zinc Chloride AA batteries, for example. These were expensive once, but as the market is now mature and billions are made every year I can buy these for about
30 cents each from my local supermarket. If lithium-sulphur batteries came out in AA form, and eventually fell in price to the same 30 cents per cell (and, in terms of costs of materials and manufacturing, there’s no real reason why they shouldn’t in the longer term), the cost of energy storage could plummet to only
$17 per kWh! By that stage petrol wouldn’t even get a look in!
8)
