Free Battery Software May Free Battery Designers

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Your editor used to teach a class on technical writing.   One of its premises was that good technical writing should be so clear it helps us see the error of our ways.  If the knights in Monty Python and the Holy Grail had done a brief description and a few simple drawings before catapulting cows over their enemy’s walls, they might have realized that they had supplied bovine bombs for the enemy to catapult back. To avoid similar defeats on the stored energy front, engineers at Washington University in St. Louis have cooked up a Cliff’s Notes of how different battery chemistries will behave when being charged.  This “back of the envelope calculation,” as Venkat Subramanian, PhD, associate professor of energy, environmental & chemical engineering and his team think of it, is an early predictor of success. Best of all, “The team developed a freely available code that battery developers can use as a model to determine the optimal profile …

Lithium Gets a Good Wrap

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Shadi Dayeh, professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering, has been designing new electrode architectures that could solve one of lithium batteries’ biggest problems.  When lithium diffuses across the surface of a lithium-ion battery electrode, it causes the electrode to expand and contract depending on its charging or discharging.  This eventually leads to cracking and ultimate disintegration of the anode or cathode – weakening and finally disabling the battery. Dayeh, working with colleagues at the University and Sandia and Los Alamos National Laboratories, came up with nanowires that, “Block diffusion of lithium (Li) across their silicon surface and promote layer-by-layer axial lithiation of the nanowire’s germanium core.” Seeing possibilities beyond his current research, Dayeh says the work could lead to, “An effective way to tailor volume expansion of lithium ion battery electrodes which could potentially minimize their cracking, improve their durability, and perhaps influence how one could think about …

Dipping and Coating for Better Batteries

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

Could dipping electrodes in a secret sauce improve supercapacitor and battery endurance and power?  Could coating cell internals be the flavor of the month?  These recipes for better batteries may improve things at a better than normal rate, if California researchers have anything to say about it. Working with his compatriot Dr. Jaephil Cho in South Korean, Dr. Cui of Stanford University has been a leader in developing improved battery technology, even developing a painted paper battery.  In an appearance at the 2009 Electric Aircraft Symposium, Cui explained a basic truth of battery development – that improvements generally created about eight percent greater power or endurance in cells every year, leading to a doubling of battery capabilities every seven and one-half years.  He aims to improve that rate of change in batteries and ultracapacitors. Although ultracapacitors are able to charge and discharge rapidly, they are only about one-tenth as energy dense as batteries of equivalent mass.  Cui and colleague Zhenan Bao …

Dr. Jaephil Cho’s Powerful Silicon Nanotubes

Dean Sigler Sustainable Aviation 1 Comment

Shortly before appearing at the fourth Annual Electric Aircraft Symposium at Rohnert Park, California, Dr. Jaephil Cho was interviewed by Esther Levy of Material Views, an online resource dealing with, as the title implies, high-technology materials.  Dr. Cho, Dean of the new Interdisciplinary School of Green Energy at Ulsan National Institute of Science & Technology (UNIST), works with lithium-ion cells, and along with Dr. Yi Cui of Stanford University, is considered among the most forward thinking researchers in the field. Where Dr. Cui’s efforts are related to development of better cathodes, Dr. Cho’s work focuses on improving anode performance. Their efforts have led to an 80-percent improvement in cathode performance, as reported in Dr. Cui’s presentation at EAS III, and a 62-percent improvement in anode performance, according to Dr. Cho’s report at EAS IV. Considering that “normal” battery advancement has been on the order of 10 percent per year for the last few decades, either of these announcements should be …

Half a World Apart, United in Their Research

Dean Sigler Uncategorized Leave a Comment

Dr. Yi Cui, a winner of the 2004 MIT Technology Review World Top 100 Young Innovator Award (among other notable awards), and Assistant Professor in the Department of Materials Science and Engineering at Stanford University, was a distinguished presenter at the CAFE Foundation’s Third Annual Electric Aircraft Symposium last April. He talked about the structure and manufacturing of lithium-ion cells, and the material limitations placed on the performance of those cells. His breakthrough in using nanowires in the cathode promises an 80-percent gain in the cell’s charge-holding ability, equivalent to ten years of the normal cell improvement of eight percent per year. The good news was somewhat of a letdown for many, who were hoping to hear of a total 10X performance improvement for the entire battery. Dr. Cui advised attendees that the introduction of similar improvements in battery anodes would be required before that quantum leap in performance could be achieved. In the meantime, as reported in our entry, …