Eva Allen

Energy storage intern improves electric vehicle battery charging research

What do science and music have in common? Why, math of course! From a young age, Eva Allen, a recent participant in the Office of Energy Efficiency and Renewable Energy’s (EERE) Energy Storage Internship, was dedicated to pursuing jazz music as a jazz vibraphone and piano player.

The DOE EERE Energy Storage Internship Program offers hands-on, practical research and development projects focused on energy storage at U.S. national laboratories.

“In both science and music, you first begin by learning the mathematical and accepted principles of the discipline,” Allen explained.

“For music, this would be first musical notes, building to scales and chords,” she said. “In chemistry, this includes mathematics, fundamental laws in physical chemistry or functional groups and reactions in organic chemistry. But it was the creative process rooted in fundamental truths leading to novel discovery that both jazz and chemistry share that drew me to a career in research.”

Eventually, her academic interest in chemistry culminated in a research assistant position at the Materials Engineering Research Facility (MERF) at Argonne National Laboratory (ANL) under the supervision of Dr. YoungHo Shin.

After two years at ANL, Allen joined Professor Jordi Cabana’s research group at UIC to pursue a doctorate in inorganic/materials chemistry. While there, she was encouraged by Professor Cabana to apply for the EERE Energy Storage Program.

Under the mentorship of Dr. Johanna Nelson Weker at the Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory, Allen spent ten weeks analyzing operando, or “in operation,” X-ray micro computed tomography (micro-CT) measurements of cylindrical cells used in electric vehicles (EVs) under simulated fast charge and drive cycles.

Micro-CT is three-dimensional x-ray imaging created by the same method used in hospital CT scans, but on a much smaller scale with massively increased resolution.

“The growing popularity for electric vehicles incites a high demand for rechargeable lithium ion batteries that can charge at faster rates,” Allen said. “EVs will always require longer refueling times than its combustion engine contender so a battery that can stably fast charge would help compensate for the current EV’s limited range.”

Because fast charging has shown to induce aggressive degradation that has large costs on the capacity retention of lithium ion batteries, Allen spent much of her time at her appointment with EERE measuring their charging cycles through micro-CT to contribute research towards improving their overall lifetime.

“Three batteries were measured during cycling after preceding fast charging cycles; the 3rd, 5th and 81st - 82nd cycles were analyzed to track structural damage at different battery life points,” Allen explained.

“To track the degradation of both the anode and cathode structures, I developed a deep learning segmentation method using the U-Net convolutional neural network. Segmentation is an essential step in taking imaging experiments limited to qualitative descriptions to quantitative conclusions,” she said.

Allen’s research into how fast charging induces structural damage will be used to better inform researchers and scientists focusing on fast-charge protocols, new battery, electrolyte and additive chemistries that could mitigate degradation in lithium ion batteries.

“During the EERE program, I added another synchrotron-based imaging technique to my skills, micro-CT, and gained new research experience in data analysis that will allow me to plan new imaging-based experiments that will continue to push the battery field,” Allen said.

“Additionally, the Energy Storage Internship has given me an unusually complete and cutting-edge skillset to pursue a career in research and development of battery materials,” she said. “In this critical technological area, my research will be a benefit to the competitiveness in battery manufacturing for the U.S. as well as to the diversity of its workforce.” 

“I would definitely recommend the program to others,” Allen said. “The most valuable experience is the mentoring relationships you receive through the EERE program, especially with the leaders in the field at national laboratories.”

“The mentorship I experienced with Dr. Johanna Nelson Weker was invaluable,” she said. “It was reassuring hearing about the path Dr. Nelson Weker took from her undergraduate studies to her current position at Stanford Linear Accelerator Center (SLAC), and these kinds of conversations have a large impact on humanizing our field and providing confidence in young researchers.”

During her appointment with EERE, Allen had the opportunity to present her research in the battery research subgroup of the Materials Science Division Group at Stanford Synchrotron Radiation Lightsource (SSRL) and the end of summer research programs seminar series at SLAC. 

Next year, she hopes to publish her research contributed during the Energy Storage Internship with Dr. Johanna Nelson Weker and plans to seek out a career in battery research and development in either a national laboratory or within a battery company.

“Wherever I do end up after earning my Ph.D., I know that I want to pursue research problems that I am passionate about and that have direct impact on the quality of life of our future society,” she said. 

The EERE Energy Storage Program is funded by the U.S. Department of Energy and administered through the Oak Ridge Institute for Science and Education (ORISE). ORISE is managed for DOE by ORAU.