Squeezing the electrons in: batteries don’t follow Moore’s Law
Deloitte predicts that battery technology will make progress in 2011 and 2012. Energy density should rise and prices should fall. Plus, batteries should become more durable and charge faster. Unfortunately, even in a good year, advances in battery technology are slow compared to advances in the devices they power. Battery technology rarely attains anything resembling Moore’s Law, which correctly predicted that computer processing power would double every 18 months. For batteries, a mere 5 percent performance improvement is a good year.
The one big exception is when the battery industry changes its underlying technology. For example, the leap from nickel-based technology to lithium ion technology nearly doubled battery energy density1. Annual improvements within the same battery technology are generally modest.
Nothing seems to beat lithium as a base material for batteries. Lithium is the third lightest element and is highly reactive, making it the best lightweight, high-density solution for the near term. Lithium is usually paired with cobaltate. Other possible partners, such as titanate and iron phosphate compounds, offer some advantages but deliver significantly lower voltages and energy yield. One scientist summed it up: "It will be refinement of existing chemistry from now on. There are no new compounds that will give higher energy density.2"
In future years, it is possible that a one percent annual improvement in lithium battery performance may become the norm. Some scientists believe that the lithium ion, which has been worked on for decades, may be close to peaking3. Changing the electrolyte, usually to a polymer, may offer some advantages but doesn’t appear to provide a significant improvement in energy density or cycle issues, which are the key attributes.
There are other views. Some commentators trumpet 10-fold4, or even 100-fold, improvements to lithium technologies5. However, even if these claims prove true, there is a long way from the laboratory bench to the consumer. Because refinements in battery technology are based on applying new materials and chemistry, “overnight” technology breakthroughs usually take decades. Research initiatives that have identified potential improvements that could improve energy density and longevity of lithium batteries are based on laboratory findings. These new approaches would still need to be assembled into batteries and moved into commercial production, which could take years6.
Although there have been hopes of new electrical storage technologies, such as ultra-capacitors, their availability does not appear to be imminent according to the energy storage and venture capital communities7.
Even if some entirely new and cost-effective non-lithium electric storage technology was developed, the industries that use batteries typically require years to revamp their manufacturing processes, integrate at the system level, prove reliability and establish safety. For example, the adoption of lithium was delayed by years due to runaway heating problems, which forced extensive engineering and safety tests8.
Utility and transportation markets would take the longest to adopt breakthrough battery technologies, but even adoption by consumer product and computer markets would take years, not months. The biggest challenges for any energy storage solution are usually reliability and durability. The only way to determine ten-year reliability is to do a ten-year test; there are no short cuts (although some scientists are working on it)9.
The availability of lithium is another issue. Although it is the sixth most abundant element in the Earth’s crust, concentrated deposits that can be extracted in an economical and environmentally clean way are rare and found in only a few locations. South American salt lakes are the primary source of lithium deposits. At one time there was some concern that a large increase in battery consumption would create a shortage, resulting in “peak lithium10." However, further studies found that although the price might need to rise to make less-accessible deposits practical, the supply is more than adequate to support even very large growth11.
Although progress in battery technology may seem slow, even 5 percent annual improvement can lead to significant gains over time. The industry will need to keep innovating, both with lithium and non-lithium technologies. Maintaining realistic expectations and timelines will likely be key.
For those who want and need better batteries, it may prove useful to focus on reducing power consumption rather than increasing energy storage. Making more efficient devices may be easier to achieve than trying to force battery technology to improve at greater than its historical rate of progress. Many of the technologies behind efficiency do improve in line with Moore’s Law or offer the potential of rapid breakthroughs.
Some older or alternative energy storage technologies (such as nickel and lead acid batteries, compressed gas or liquid, miniature fuel cells and flywheels) may remain viable choices if lithium technology continues to progress slowly. For example, lead acid batteries can be combined with newer technology, such as super-capacitors, to produce surprisingly good results using core technology that is 150 years old12.
1 Is lithium-ion the ideal battery?, Battery University:http://batteryuniversity.com/index.php/learn/article/is_lithium_ion_the_ideal_battery
2What does the future hold for battery technology?, ICIS, 9 July 2008:http://www.icis.com/Articles/2008/07/14/9139058/what-does-the-future-hold-for-battery-technology.html
3Building a better battery, Associated Press, 17 October 2005:http://www.msnbc.msn.com/id/9689826/ns/technology_and_science-innovation/
4A tenfold improvement in battery life?, CNET News, 15 January 2008:http://news.cnet.com/A-tenfold-improvement-in-battery-life/2100-1041_3-6226196.html
5A Better Battery? The Lithium Ion Cell Gets Supercharged, Scientific American, 11 March 2009: http://www.scientificamerican.com/article.cfm?id=better-battery-lithium-ion-cell-gets-superchargedand Toshiba – Rechargeable Batteryhttp://www.scib.jp/en/
6The Innovation Process for Battery Technologies , ATP Working Paper Series, 21 July 2005:http://www.atp.nist.gov/eao/wp05-01/chapt3.htm
7Deloitte Cleantech in Canada seminar, 4 November 2009: http://cleantechincanada.com/?p=183
8Is Lithium-ion safe?, By Isidor Buchmann of Cadex Electronics, September 2006: http://www.buchmann.ca/article28-page1.asp
9A Quicker Test for Hybrid Batteries, Technology Review, 4 August 2010:http://www.technologyreview.com/energy/25925/
10Peak Lithium?, EV World, 28 January 2007:http://www.evworld.com/article.cfm?storyid=1180
11An Abundance of Lithium, R. Keith Evans, March 2008: http://www.che.ncsu.edu/ILEET/phevs/lithium-availability/An_Abundance_of_Lithium.pdf
12A Cheaper Battery for Hybrid Cars, Technology Review, 24 January 2008:http://www.technologyreview.com/energy/20105/