Case Study

Ansys Software Helps UKBIC Model and Predict Electrode Behavior Pre- and Post-Calendering to Minimize Defects

“Thanks to this collaboration with Ansys, we have made a significant step forward in modelling the calendering process. We now have a qualitative tool that helps us better understand how key elements of the process influence calendering behavior and the formation of defects. This insight provides a strong foundation for guiding future process optimization and more physics informed decision making"

— Helen Walker
Senior Process Simulation Engineer / UK Battery Industrialisation Centre (UKBIC)

Calendering, the precise rolling and compressing of electrode materials, is crucial during battery manufacturing to achieve the desired electrode thickness and density. It is the last electrode processing step where performance and mechanical stability can be controlled. Further, it is the state of uniformity realized during calendering that supports optimal electrochemical performance. However, this rolling and compressing process is prone to producing material defects, such as embossing (buckling of the collector foil) and corrugation (contraction or folding of the coating) in proximity to the electrode. For UKBIC, both defects were suspected to be due in large part to roller geometry, process parameters such as web tensions and material variability, resulting in costly process adjustments and material waste.

Challenges

Traditionally, UKBIC quality concerns were managed through live process adjustments and by discarding defective material during calendering. Instead, the team believed it would be more valuable to forecast and mitigate material defects, including embossing and corrugation, in advance of production runs. However, previous methods were found to be ineffective in identifying when and how such defects might emerge during calendering.

Further, the calender rollers on its Industrial Scale-up Line (ISL) — a line designed to support companies in developing and scaling their battery technologies — are not perfectly cylindrical, but instead have a crowning profile, with a slightly larger radius near the center due to the large capital expenditure and time required to procure calendaring rollers with different specifications.

Engineering Solutions

UKBIC, in collaboration with Ansys, part of Synopsys, has developed a thermomechanical model of the calendering process. Ansys Mechanical software was used for mesh generation and the majority of the finite element model setup. LS-DYNA was the software determined best suited to perform the time-explicit structural simulations needed to complete the model setup, solve the numerical model, and post-process results.

Benefits

A crushable foam, temperature-independent model provided a faster way to assess not only the impact but the physics behind how crowning affects the formation of calendering defects.
The model was used predict the macroscale buckling behavior of the electrode during and calendering to further understand how defects are initiated.
Using LS-DYNA software in conjunction with the developed model, UKBIC could predict the local stress and strain field within the electrode as a natural consequence of solving the finite element model.
Comparing the predicted local stress with material failure strengths, it was possible to determine whether web breaks (foil tear) might occur with a given combination of line load, web tension, and line speed factors.
Evaluation could be further contextualized according to different geometry configurations, including multi-lane and intermittent coating, coating thickness variability, corrugation coating defects, and the effect of roller dimensions on coating.
With the given model constraints, a qualitative model was generated enabling web embossing predictions.

In future work, UKBIC plans to couple particle scale simulations performed in Ansys Rocky with the LS DYNA calendering model, enabling investigation of how different binder configurations and electrode chemistries influence process behavior. This approach will allow coating performance to be linked to advanced nonlinear viscoelastic material models in LS DYNA software which capture the complex response of electrode materials under realistic loading conditions.

Other future areas of investigation will involve anisotropic foil material, or substances whose physical properties vary subject to directional measurement, and temperature dependence on material properties.

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Technology Used

Ansys LS-DYNA® nonlinear dynamics structural simulation software
Ansys Mechanical™ structural finite element analysis software

Company Description

The UK Battery Industrialisation Centre (UKBIC) is the UK’s national manufacturing development facility, providing scale-up, laboratory expertise, and module and pack assembly, and help developing skills to support the sector.

By bridging the gap between research and high-volume manufacturing, UKBIC plays a critical role in supporting the UK's transition to net zero and strengthening its position in the global battery supply chain. UKBIC provides state-of-the-art equipment, technical expertise, and training to help manufacturers and researchers validate processes, optimize performance, and reduce risk before committing to large-scale investment.

The facility offers both pilot and industrial-scale lines, enabling customers to trial new materials and processes under real-world conditions. Based in Coventry in the United Kingdom, UKBIC welcomes manufacturers, entrepreneurs, researchers, educators, and wider supply chain companies working within the battery industry worldwide.

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