Status of Energy Storage Technology

Getting from Here to There

Sounds great, right? There are just a few hurdles to jump along the way.

First, the world is rapidly changing - the rise of massive consumer economies in South America, India and Asia will place unfathomable strain on global resources: water, food, energy and commodities such as rare earth metals. The NiMH batteries in the Prius rely on the rare earth, lanthanum - which could never supply the tens of millions of hybrids a year. That's one example of the barrier we'll soon be bumping up against - batteries require huge volumes of raw materials.

Second, today's batteries are approaching performance targets, but to electrify personal transport, they need to be much more cost-effective, long lasting, and abuse-tolerant. The reason plug-ins (PHEV) and electric cars (EV) are so pricey is because of the high price of Li batteries. A PHEV manufactured this year costs as much as $18,000 more than a conventional vehicle - subsidies in the tens to hundreds of billions of dollars over decades will be necessary for PHEVs to seriously penetrate the U.S. automotive market.

Even with that level of investment, PHEVs wouldn't significantly impact oil consumption or carbon emissions before 2030, according to the National Research Council. Assuming rapid technological progress, appropriate levels of subsidies and consumer acceptance, they believe no more than 40 million PHEVs will be on the road by 2030, and they see 13 million as a more realistic number.  

DOE's Vehicle Technologies Program doesn't think NiMH systems can provide the energy and power for a PHEV battery for more than a 10- or 20-mile range, and although Li batteries can do the job for 10 miles, getting them to the 20- to 40-mile range is difficult. Challenges for developing and commercializing PHEV batteries are:

• Cost: Li batteries have to come down in price 3-5 times per kilowatt hour (kWh). Costs include raw materials, materials processing, cell and module packaging, and manufacturing. Sandia National Lab estimates the current cost of advanced lead-acid batteries is $500 per kWh and Li batteries is $1,333 per kWh.
• Performance: for a PHEV range to reach 40 miles or more, batteries need much higher energy densities to meet volume and weight targets and to reduce the number of cells in a battery, which would bring down costs.
• Abuse Tolerance: Li batteries need to improve in abusive conditions. They tend to overcharge, over-discharge, or even explode in high-temperature environments.
• Life: it's not clear whether batteries can meet the target of hundreds of thousands of cycles of shallow and fewer deep cycles.