EV Battery Safety: Simulating Thermal Runaway with Ansys Mechanical & Fluent

 Predicting the Unpredictable: Advanced Multi-Physics for Battery Management Systems (BMS)

In 2026, the primary challenge for the automotive industry is not range—it's safety. Thermal Runaway in Lithium-Ion batteries remains a critical risk. Using Ansys Multi-physics, engineers can now simulate the complex chain reactions that occur when a cell fails due to internal short circuits or mechanical impact.

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1. The Mechanics of Failure: Structural Integrity

Before the fire starts, there is usually a mechanical trigger—a crash or a puncture. In Ansys Mechanical, we use explicit dynamics (LS-DYNA) to simulate the deformation of the battery pack housing.

• Material Modeling: Accurate stress-strain curves for aluminum or composite enclosures.
• Short Circuit Prediction: Identifying the exact moment of separator failure within the jelly roll.

2. CFD Analysis of Heat Propagation

Once a cell enters thermal runaway, it releases an enormous amount of energy in seconds. In Ansys Fluent, we model the Cell-to-Cell Propagation.

Pro Tip: Use the Equivalent Circuit Model (ECM) or NTGK model in Fluent to calculate the volumetric heat source during the exothermic reaction.

Key focus areas for 2026 simulations:

• Venting Gas Flow: How toxic gases are exhausted from the pack.
• Coolant Interaction: Can the Battery Thermal Management System (BTMS) stop the propagation?

3. Mitigating Risk: Designing Better Firewalls

By coupling Mechanical and Fluent, you can optimize the internal firewalls (mica sheets or aerogels) between cells. The goal is to ensure that if one cell fails, the rest of the pack remains stable, giving passengers enough time to exit the vehicle.

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Frequently Asked Questions (FAQ)

Q: Which Ansys solver is best for battery fire simulation?
A: Ansys Fluent is the primary solver for fluid flow and heat transfer, but Ansys Rocky (DEM) is increasingly used to simulate the ejection of solid particles during battery venting.

Q: Is HPC required for battery pack simulations?
A: Yes. Modeling a full 800V battery pack with thousands of cells requires significant HPC power. See our Hardware Guide for the best CPUs for this task.

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Meta Description: Prevent battery fires with simulation. Learn how Ansys Mechanical & Fluent model thermal runaway and propagation in EV battery packs for 2026 safety standards.
Labels: Battery Safety, Thermal Runaway, Ansys Fluent, EV Engineering, Battery Thermal Management, Automotive Simulation, Li-ion Battery, Multi-physics.