Researchers from the Fraunhofer Institute for Industrial Mathematics ITWM in Kaiserslautern are developing software to simulate lithium-ion batteries as part of the Fraunhofer System Research for Electromobility (FSEM) project. The Battery and Electrochemistry Simulation Tool (BEST) is intended to speed the development of cells optimized for automotive applications.
Battery performance depends on the materials used in the components. These materials need to work in harmony with each other. Various material combinations can be simulated using our software, enabling us to come up with the ideal mix. The kind of trial-and-error testing done in the past is no longer necessary.—Jochen Zausch, a scientist in the Complex Fluids group at Fraunhofer ITWM
The Fraunhofer ITWM researchers are simulating the entire battery cell on macroscopic and microscopic levels as well as the transport and reaction processes of the lithium ions themselves.
|Microscopic representation of the battery using BEST software. The electrodes are at the left and right. Click to enlarge.|
We can show the microscopic structure of the electrodes. Every individual pore measuring 10 micrometers can be seen—something none of today’s off-the-shelf programs can do. The position and shape of the electrodes can also be varied.—Jochen Zausch
By resolving the structure of the electrodes in three dimensions, parameters such as lithium ion concentrations and current density can be calculated. For these computations a specialized “Finite Volume” code is used that was developed and implemented at the ITWM. The distribution of the current flow provides an indication of heat production in the battery. Therefore, the software can pinpoint possible hotspots that may overheat and can lead to ignition of the battery. Aging effects can also be assessed using BEST. The scientists intend to upgrade the program to include aging models which would make these kinds of studies even easier to conduct.