Saturday, November 26, 2011

Moore's Law For Batteries, Don't Count On It

Some people have expressed an opinion that we will see a Moore's law for batteries.  I think this is unlikely for two basic reasons:  We've seen no such thing to date and batteries are not computer chips.  Moore's law states that the density of transistors which can be put on an integrated circuit will double every 18 months, and so far it has held true.  This has led to faster computer power and lower costs for electronics.  What we've seen in lithium battery advances has mostly been steady advances of 5% a year with occasional jumps.  I do expect we'll see more dramatic advances in the future as the sheer volume of research on the topic is increasing and none of the current chemistries are near their limits, to say nothing of future chemistries.  Battery development is akin to squeezing a balloon, one end gets smaller while the other end bulges larger.  Batteries have four parameters that need to be optimized, energy density, power delivery, useable life, (cycle and calendar), and safety.  In batteries when you optimize for energy density you tend to decrease longevity, if you optimize for power you lessen energy density, and so on.  The key is of course getting all these into one package, and ultimately at an affordable price, which really adds a fifth parameter just as important as the other four.  It doesn't matter how good a battery is if it can't be produced at a reasonable cost.  Unlike computer chips most of the costs of batteries are the high purity materials that must go into them.  Advances come by using those materials in better ways, by finding better materials, and by improving the construction process.  This mostly comes from constant research, trial and error, and tweaking and optimizing assembly lines to improve production yields.
A lot of work is being done in the field and there are very promising developments being announced on a regular basis but none as of yet has made it to market in an affordable product.  I expect at some point some of them will and we will see a major jump in all battery parameters, but don't expect a steady doubling of all parameters every 18 months.  Of course I'd be quite happy to be proven wrong in this case.

Sunday, November 6, 2011

Is It Time To Restructure EV Subsidies?

Obviously I'm a strong proponent of electric vehicles and I think subsides for their development are necessary and money well spent.  However that doesn't mean we can't improve the way that money is distributed.  Specifically addressing the vehicle purchase rebate I don't think we need to subsidize vehicles such as the Fisker Karma, a $90,000 plug in hybrid vehicle with poor efficiency.  Frankly I'm not even convinced we should continue to offer purchase incentives for vehicles over the $50,000 dollar mark, which would include the Tesla Model S.  It's an awesome vehicle that needs no support other than what it is and it's target purchasers really don't need the financial incentives.  I think it can stand on it's own, and the money can be better spent on building out the charging infrastructure and driving the development of lower priced EV's.  We should reward efficiency by tying incentives to some relationship between vehicle watt hour per mile energy use as well as it's overall cost.  This would push manufacturers to get more mileage out of smaller battery packs by using better aerodynamics and lighter weight materials.  While the LEAF is a good EV it's drag coefficient is too high, as is it's weight, and consequently it's range suffers a bit.  We need to rethink and redesign the automobile to get the most out of our battery packs, the single most expensive component.  Jamming in a huge battery pack is fine for an upscale luxury vehicle such as the Tesla Model S that can absorb the cost but obviously mass market vehicles cannot do the same, nor is that a sustainable and efficient way forward.
With the current political and social climate pushing for reduced government spending and an increasing attack on "green" products it's hard to justify giving tax breaks to people who really don't need them.  If EV's are seen as toys for the rich it's going to be difficult if not impossible to continue to get funding for battery research and charging infrastructure development.