A new manufacturing process developed by Xerox's Palo Alto Research Center (PARC) will increase the energy a lithium-ion battery can store by 40%. The technology is similar to that of printed solar cells.A battery, as you might know, has two primary components: the electrodes and the electrolyte. In lithium-ion batteries, its electrodes swing both ways--serving as either anodes or cathodes--which makes it rechargeable. And with current technology, there is no way to squeeze more juice into these guys. For one, half of the battery is filled with materials incapable of holding a charge--polymers and foils. Secondly, electrodes tap out around 100um. Using bigger ones only decreases the rate at which lithium-ions are absorbed and subsequently the battery's performance.
Scott Elrod told me about their goals so far and that, "We [PARC] should be able to achieve an electrode thicknesses of up to 500um." He is PARC's Director of Cleantech Innovation Program. Their approach works by printing the electrode in parallel with a highly conductive (and super top-secret!) membrane.
"By interleaving layers of the cathode material with other layers of a porous material to provide pathways for the Li ions, we can make the electrode substantially thicker -- without increasing the resistance to Li ions getting into the full volume of the cathode. This enables higher storage density, reduced yield loss due to shorting, reduced production time, and other benefits," he said.
However, there are still some obstacles to figure out. For example, is the conduit compatible with both the electrode and the electrolytes? What are its effects on battery life? But this technology could be a big step for the electric vehicle.
The U.S. Department of Energy has a goal of reducing car-battery costs by 70% by 2014 and it is doubtful this breakthrough will help. The DOE says the tipping point for mainstream adoption of electric vehicles is when the batteries cost around $350 kWh. Which doesn't seem to night as the all-electric Nissan Leaf is guesstimated to be around $1,000 per kWh. Nissan refuses to comment on the actual cost of the car's battery pack but other than to say it will definitely lose money out of the gate.
Government and private investors have already put forth serious cash into the field of materials science in hopes to drive down the cost of electrodes but active materials only account for 20% of the battery's overall cost (less in hybrid applications). "The costs could be very similar, except for the increase in the cathode material," confirms Scott.
It seems the free gift with purchase here is not going to be shaving off the cost but extending the cars range to meet our perceived driving needs. As drivers of the Chevy Volt are already reporting 1,000 miles per tank, it will be interesting to see if PARC can change the electric car industry as they did solar.
Source: Technology Review