Rapidly Discharging Lithium-ion Batteries & 3D Digital Image Correlation

"Investigating the strain and degradation parameters of rapidly discharging Lithium-ion batteries using 3D digital image correlation"
Adaptive Real-Time Systems (ARTS) Lab
College of Engineering and Computing
University of South Carolina
Battery: 18650 2500mAh 20A
Battery Test System: NHR 9200
Digital Image Correlation System: VIC-3D from Correlated Solutions
Correlated Solutions recently assisted in an important research project in the College of Engineering and Computing at the University of South Carolina with members of Dr. Austin Downey’s research group who are investigating the degradation parameters of rapidly discharging Lithium-ion batteries in the ARTS lab (Adaptive Real-Time Systems). In some cases - especially in defense and aerospace applications - it is necessary to push battery performance to extreme limits. Dr. Downey’s team, working with support from the NSF and Airforce Research Laboratory are using a NHR 9200 Battery Test System to investigate the material characteristics of an 18650 2500mAh 20A battery as it rapidly discharges.
In this test, the focus is on Current Interrupt Devices (CID). CIDs play a critical role in ensuring safety in high-performance battery applications by interrupting current flow when it exceeds a predetermined safe limit. This prevents battery cells from overheating, which can lead to damage, fire, or even explosion. In high-performance batteries that are designed to deliver large amounts of current very quickly, this protection is essential to prevent catastrophic failure.
Generally, when batteries are subjected to high stress, the electrolytes inside the battery evaporate which creates an internal pressure prior to the triggering of the CID. In earlier stages of the research, strain gauges were deployed in an attempt to measure this building load. But the small size of the strain gauges created difficulty attaching the sensors and the limited measurement area proved prohibitive to meet the goals of the test. The team needed the non-contacting, full-field strain and deformation data provided by the VIC-3D digital image correlation system. DIC provided full-field displacement and strain measurements during extreme discharge conditions to identify the precise change in radius of the battery that immediately preceded triggering of the pressure-based CID.
The DIC setup included two 5 MP cameras with 50 mm lenses and the standard Correlated Solutions 1050 LED Light Kit with linear polarizers to help reduce reflections. After the cameras and battery were in place, the system was calibrated using a Correlated Solutions 5 mm calibration target.
Because triggering the CID renders the battery useless, it is vitally important to understand the degradation parameters of Li-ion batteries as they approach failure conditions. This research is an important step toward the development of future battery applications, and we’re proud to play a part.
For more specific information on the DIC setup for this test: www.correlated...
For more information on the ARTS lab at USC: cse.sc.edu/~ad...
Contact us today to explore the powerful range of digital image correlation systems with one of our sales engineers: www.correlated...

[@kevinstestengineering1620]

I just noticed the overlaying of the 3D data onto the cleaned-up video of the battery. That is just *chef's kiss*. I"m going to have to have a go at that.

[@CorrelatedSolutions]

Thanks, this is one of our first attempts to really stretch the legs of the new timeline features in VIC-3D 10. Once it gets widely released (next month at SEM), we’re excited to see what kind of DIC visualizations our clients dream up.

[@JuanpabloHernandezFuente-dp3zu]

Is DIC method effective measuring vibrations in big machines, like engines or bombs? or is it less effective when the object is too big

[@CorrelatedSolutions]

Thank you for this question. As a method, DIC scales extremely well to large sizes, and we have significant experience with large scale testing (from engine castings to full scale wind turbine blades and rocket fairings). A special calibration method is used to handle the large field of view, and a different set of techniques are used to apply speckle patterns. There are several large scale application examples on our website (www.correlatedsolutions.com/applications), and our Sales Engineers are always happy to answer more specific questions about your testing requirements (www.correlatedsolutions.com/contact). We look forward to hearing from you soon.