By Eric Loveday · April 08, 2013
Some arguments against electric vehicles are difficult to counter, while others are not.
Battery cost is one of those arguments often presented that can’t be dismissed with ease. Most studies continually suggest that battery prices will fall rapidly in the coming years, but the reality today is that the lithium-ion battery pack that powers the current crop of electric vehicles is expensive. Some reports put the average lithium-ion pack price at approximately $15,000.
But that will drop quickly over time, right? Well, as Fred Schlachter writes in a recent issue of Proceedings of the National Academy of Science, battery prices will indeed drop, but at nowhere near the rapid pace some predict. Furthermore, advancements in lithium-ion technology appear to be linear, rather than exponential.
Schlachter brings mobile phones and computers into the mix to present his case. According to Schlachter:
“The public has become accustomed to rapid progress in mobile phone technology, computers … These developments are due in part to the ongoing exponential increase in computer processing power, doubling approximately every 2 years for the past several decades. This pattern is usually called Moore’s Law and is named for Gordon Moore, a cofounder of Intel.”
But, as Schlachter claims, Moore’s Law doesn’t apply to battery technology and here’s his reasoning why:
“The reason there is a Moore’s Law for computer processors is that electrons are small and they do not take up space on a chip. Chip performance is limited by the lithography technology used to fabricate the chips; as lithography improves ever smaller features can be made on processors.”
“Batteries are not like this. Ions, which transfer charge in batteries, are large, and they take up space, as do anodes, cathodes, and electrolytes. A D-cell battery stores more energy than an AA-cell. Potentials in a battery are dictated by the relevant chemical reactions, thus limiting eventual battery performance. Significant improvement in battery capacity can only be made by changing to a different chemistry.”
Graphics via The Washington Post’s Wonkblog.
While it may be true that lithium-ion battery technology is limited by several factors and that improvement will come slowly, solid-state technology seems to be on the horizon. Toyota says it will commercialize a solid-sate battery by 2020. If accomplished, then electric vehicle battery technology will go from today’s slight year-to-year- advancements to a huge leap as soon as solid-state hits the scene. Then, it’s likely that progress will slow until the next “breakthrough” emerges.
The chart above sums up the basic situation: The overall cost of batteries will go a long way to determining how quickly electric vehicles gain in popularity. But the much, much harder question is whether big, long-shot chemical breakthroughs are the only thing that will get us there, or whether smaller steps might do the trick.
Progress is progress though. In the end, it only matters that the chosen technology continues to advance.