Thermal Runaway Propagation Modeling to Design Safer Battery Packs
Thermal runaway is one of the most critical safety challenges in battery systems, particularly for cylindrical cell modules. Detroit Engineered Products (DEP), a leader in engineering solutions, conducted this case study to demonstrate their competency in TR propagation analysis, considering the market demand for a solution to TR analysis. They sought a solution that could effectively mitigate thermal runaway propagation while maintaining design resilience and cost efficiency. This is where oorja’s cutting-edge battery simulation technology stepped in, enabling DEP to take on this problem.
The project’s objective was to validate a 3×3 module of the NMC 21700 cylindrical cell TR model using the published data and demonstrate the impact of module design on the TR propagation rate. DEP aimed to derive insights for improving safety and enhancing design resilience by studying the effect of cell spacing and module configuration on TR propagation. oorja’s platform— with its physics-informed ML— provided a robust simulation framework, enabling DEP to explore these aspects with precision and reliability.
3×3 module of NMC 21700 cylindrical cells designed by DEP
Using oorja’s platform, DEP modeled thermal runaway conditions in a 3×3 module of NMC 21700 cylindrical cells with two different configurations: S-type and M-type. The flexibility of oorja’s Battery Application Suite enabled DEP to design their battery pack incorporating factors such as, boundary conditions, pack material, and initial loads, creating a highly realistic simulation environment. Key to the approach was the use of Accelerating Rate Calorimetry (ARC) data, which allowed DEP to build a zero-dimensional thermal model. Moreover, since the oorja HEAT app allows for the simulation of the different pack configurations with different trigger locations and power profiles, it enabled a more accurate representation of experimental conditions and provided flexibility in testing the TR propagation behavior of the pack under different what-if scenarios for DEP.
DEP’s Analysis Set-up with Loads and Boundary Conditions
On running the simulation, the battery design exhibited thermal runaway as can be seen below:
3×3 module of NMC 21700 cylindrical cells exhibiting thermal runaway
On running different iterations, DEP discovered that increased cell-to-cell spacing significantly reduced heat transfer between cells, effectively containing thermal runaway. They found that in all the cases tested, thermal runaway did not propagate, and increased space reduced heat transferred to other cells from the trigger cell.
Cell-to-cell Spacing is 1mm
Cell-to-cell Spacing is 2mm
Cell-to-cell Spacing is 4mm
This insight demonstrated the value of optimizing cell spacing as a practical and scalable design improvement for enhancing battery safety. Additionally, variations in tab connection morphology—comparing M-Type and S-Type configurations—revealed that the former was more efficient and safer compared to the latter, further guiding safety-focused design decisions.
Simulation Results: Effect of Tab Connections Morphology
Validation of the simulation results was conducted using experimental data from peer-reviewed literature. The alignment between the simulation outcomes and empirical observations reinforced the credibility of the findings and underscored the reliability of oorja’s modeling approach. Combining physics-based simulations with data-driven insights, this hybrid methodology enabled DEP to achieve high-fidelity results while avoiding the inherent risks and costs associated with physical testing.
Results Validation Against Experimental Data for S-type connectors
Results Validation Against Experimental Data for M-type connectors
Through this collaboration, DEP enhanced its understanding of thermal runaway mechanisms and demonstrated the viability of simulation-driven design improvements. The ability to analyze and predict the effects of various design parameters in a oorja’s Battery Application Suite, provided a safe, efficient, and cost-effective alternative to traditional testing methods.
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About Detroit Engineered Products: Detroit Engineered Products (DEP), founded in 1998 in Troy, Michigan, is an engineering solutions and product development company. DEP offers services across industries such as automotive, aerospace, and healthcare. With a global presence spanning Europe, China, Korea, Japan, and India, DEP provides innovative solutions that reduce development cycles and enhance product optimization.