$20/kW and that the incremental cost for the technology improvements, which includes enhanced aftertreatment, will be $10/kW. The team has not been able to confirm these estimates with public domain data.

Electrochemical Energy Storage

Energy storage is essential for any type of vehicle that recovers part of the kinetic energy that would otherwise be lost to heat dissipation during braking (regeneration) and/or operates without the primary energy converter (e.g., ICE or fuel cell) for some or all of its operation; these vehicles would include HEVs, PHEVs, battery electric vehicles (BEVs), and hydrogen-fueled fuel cell vehicles (HFCVs). While there are many ways to store energy (flywheels, compressed air, elastomers, hydraulic springs, batteries, capacitors, etc.), the Partnership has focused on electrochemical storage—primarily batteries and to a lesser extent ultracapacitors. Batteries can serve as primary energy sources onboard the vehicles as well as being a means of recovering kinetic energy, unlike some of the other energy storage technologies that serve better as short-term power devices.

The emphasis on batteries is even greater with the Obama administration, which has announced a goal to “put 1 million plug-in hybrid cars—cars that can get up to 150 miles per gallon—on the road by 2015 …” (Satyapal and Davis, 2009). Conceptually, PHEVs are very similar to HEVs but require far more battery energy, enough to provide an all-electric-design driving range of (typically) 10 to 40 miles. At this time, versions of lithium-ion (Li-ion) batteries with different chemistries seem to be the most likely candidates, and these dominate most Partnership battery research activities.

Among the accomplishments are the following:

  • Three Li-ion battery chemistries classified by the cathode material, including (1) lithium nickel, cobalt and aluminum; (2) lithium iron phosphate; and (3) lithium manganese spinel and a carbon anode, have been developed and tested for HEV applications. Since the Phase 2 review, there has been improvement in discharge and regenerative pulse power rating, calendar life as measured by accelerated testing, and increased cycle life. This applies to all three of the chemistries discussed. Laboratory data indicate that energy and power density requirements for HEVs will be met. With only Daimler having a production HEV with Li-ion batteries, the real cost is still unknown. However, recent announcements about the Nissan Leaf indicate that the cost and durability for a BEV, which is a much tougher application, may be within reach.

  • Safety is an important factor in the design of the battery. To determine safety, the Partnership has conducted extensive abuse testing, including mechanical (crushing, perforation, and shock), electrical (external shorting, overcharging, and overdischarging), and thermal (over-temperature



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