Electric-Car Component Makers Power Up
ByGeorge DeVaux, RealMoney Contributor , On Wednesday January 12, 2011, 2:30 pm EST
High petroleum prices will help to drive the market for electric storage devices that power electric vehicles. And two companies that produce the components for electric cars are worth watching.
Electric vehicles need to store electricity. Batteries -- think A123 -- and capacitors -- think Maxwell Technologies -- use different storage approaches.
A rechargeable battery uses reversible chemical reactions to store the energy. An EDLC (electric double layer capacitor) stores the electrons on the surface of its component material. A material which does not conduct electricity (a dielectric) separates the positive and negative charge layers. (Note that these types of capacitors are sometimes called ultracapacitors or supercapacitors. These terms refer to the relative energy density, and the total energy storage can range from tiny -- as in a cell phone -- to very large.)
For the transportation market, the significant parameters include cost, energy density (watt hours per kilogram, or W•h/kg), power density (a measure of time to charge), volumetric energy storage and lifetime (measured in charge discharge cycles).
The energy density of a lead acid battery ranges from about 30 to 40 W•h/kg. For a lithium ion battery, the energy density is on the order of 160 W•h/kg. This dramatic differential helps explain the use of lithium ion batteries in automobiles.
For the next few years, lithium ion batteries will supply the bulk of the power storage market for electric vehicles such as the Volt produced by General Motors. Ultracapacitors will serve as a complement in regenerative braking and to provide surges of power for acceleration and hill-climbing. Over several years, ultracapacitors may close the density gap with batteries.
A123 makes lithium ion batteries. The transportation sector accounts for about 50% of its product revenue. Products for the electric grid account for about 30%. The balance is for general commercial purposes. In its third-quarter report, A123 revealed that its transport customers are ramping at a slower pace than originally anticipated. A six-month delay is not critical, but the cash runway is getting shorter. A significant ramp in sales could alter the cash flow from negative to positive with a significant impact on the price-to-sales ratio.
Batteries require very long discharge/charge cycles (hours), vs. seconds for ultracapacitors. Batteries can be cycled only a few thousand times vs. several hundred thousand times for ultracapacitors. Batteries currently provide higher energy densities, but that advantage may disappear.
Maxwell Technologies produces capacitors for a number of industry sectors. It recently received a $1.7 million contract from DARPA (Defense Advanced Research Projects Agency) for an integrated system that combines an advanced capacitor, an advanced battery and an integrated management system. Additional contract phases could add $8 million. These contract amounts are significant when compared with Maxwell's R&D budget of about $15 million per year. Also significant is DARPA's approach to rapidly fielding technology. The organization is focused on getting technology into the hands of the leading developer as fast as practical. This contract could significantly affect Maxwell's top line within a few years.
EDLCs are used in regenerative braking systems to store energy and to reaccelerate the vehicle. More than 1,000 buses use EDLCs as the primary energy system. Because the charge range is typical less than 10 miles, these bus systems require recharge stations along the route.
Most EDLCs use activated carbon as component material for the storage of electric charge. Substantial improvement in the amount of surface area will come from other forms of carbon such as nano tubes, graphene, aero gels and carbides. Improvements in the dielectric layer will permit higher voltages. An improvement by a factor of 10 in energy density is likely in the commercial marketplace over the next few years. Ford has sponsored significant carbon nano tube work for EDLCs at the Massachusetts Institute of Technology.
Currently, commercial EDLCs are available with an energy density up to 30 W•h/kg. Laboratory demonstrations are already at three times that level.
finance.yahoo.com/news/ElectricCar-Component-Makers-tsmp-353746113.html
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