Technical Papers and Presentations

Over time, rechargeable batteries degrade and eventually stop working. You see some combination of declining capacity, rapid self-discharge, and reduced power. Degradation mode depends on battery design, but also on the application. Often, multiple physical processes contribute to degradation. In the laboratory, you can measure performance degradation. You can dissect the battery to discover physical changes and conjecture about underlying causes. To tie physical changes and underlying causes to performance degradation requires electrochemical modeling.

A new, high-energy, sodium battery has commercial applications, including hybrid locomotives. A detailed electrochemical model has been implemented with FEM. Before constructing the model, we measured chemical kinetics for the several phenomena comprising battery operation. The resulting model simulates measured battery performance well, while providing insights into degradation processes.

Keynote speaker's biography:

Michael earned his doctorate in Chemical Engineering for his investigation of nanostructure in segmented co-polymers. Professionally he has focused on materials and energy research at ExxonMobil, Novartis, Honeywell, Plug Power and GE. At GE Global Research, he is developing a high-energy sodium battery for use on a hybrid diesel-electric locomotive. He leads a team investigating electrode microstructure and chemistry. To link structure to performance, Michael started a modeling initiative in 2007.

Michael Vallance was one of the keynote speakers at the COMSOL User's Conference, fall 2009 in Boston.