Electric vehicles

It is no secret that the automotive industry is currently undergoing a massive transformation and many contending technologies are competing for the various automotive use cases.

We at Optumatics are strong believers in the potential for Electric Vehicles of various types (BEV, HEV, etc.) to dominate the passenger car and light-duty transportation market.

We have also recognized the challenges in designing electric vehicles early on and have prepared for these challenges in anticipation of our clients’ demand for high-fidelity analysis.

What we do?

Examples of the problems where we have helped our customers:
  • 3D simulation of thermal runaway event
  • Battery pack design
  • Full electric vehicle energy management
  • Battery lifetime simulation (degradation analysis)
  • Electric motor design

Battery Pack Thermal Runaway Simulation

Thermal runaway is one of the most hazardous safety risks in electric vehicles for both vehicle passengers as well as a vehicle’s surroundings.

The need for numerical modeling of thermal runaway events is mainly due to two reasons:

  • the complexity of the physical processes occurring during thermal runaway and the interactions between these processes.
  • the difficulty of extracting sufficient information from experimental thermal runaway testing (e.g., obtaining cell internal temperatures, etc.) as well as the costly nature of building enough prototypes to reach a safe design.

For these reasons, it is quite useful to have a numerical modeling framework that can provide enough understanding of the physics behind thermal runaway propagation as well as identify the key factors that affect the propagation within a module as well as within a battery pack.

We have used a methodology where computational fluid dynamics and heat transfer are coupled with an electrochemical model to simulate the following phenomena:

  • Heat release from the cells undergoing thermal runaway. The heat release was calculated using electrochemical models describing the sequence of events during a thermal runaway event.
  • Propagation of thermal runaway from the initial cell to the neighboring cells
  • Propagation of thermal runaway from one module to another

Venting gas and solid ejecta from the cells undergoing thermal runaway.

Battery Pack Design

According to battery pack design standards, several following tests should be considered when designing a battery pack. Some of these tests are:

  • Self-weight Test
  • Vibration/NVH
  • Crush/Impact Test
  • External Short Circuit Protection
  • Fire Resistance – Short/ Long Duration

Carrying out all these various testing procedures on real-life prototypes can be impractical. For this reason, building a digital-twin for the battery pack can help design teams optimize their designs and ensure that they pass all the required tests.

The digital-twin can be used to perform the following simulations:

  • Static and dynamic load testing
  • NVH (noise, vibration and harshness) modeling
  • Fatigue modeling
  • Buckling analysis
  • Cooling plate thermo-mechanical design
  • Cooling circuit controller design

Full Vehicle Energy Management & Aging Analysis

It is quite useful for electric vehicle (BEVs and HEVs) designers to understand the various system-to-system interactions on a vehicle-level. Examples of these are:

  • Effect of ambient operating conditions on battery pack temperatures, overall vehicle cooling requirements, energy efficiency considerations and incremental battery degradation.
  • Effect of customer drive cycles and driving habits on energy efficiency and battery pack lifetime.

For this reason, we recommend performing full vehicle energy management analysis and aging simulations that spans the full battery pack lifetime. This analysis incorporates the following modeling capabilities:

  • Vehicle dynamics analysis of a drive-cycle along with powertrain losses modeling
  • Electrical analysis of a battery using an equivalent circuit modeling approach
  • An electrochemical approach for modeling battery aging
  • 3D thermal simulation of the vehicle components, exhaust flowline, battery cooling circuit and thermal comfort of the vehicle cabin.

This analysis is available as a dedicated workflow with an accelerated problem setup time on our software EVMATICs.

Electric Motor Design Using 3D Electromagnetic Simulations

We at Optumatics also offer CAE support to electric motor designers in solving complex design issues in electric motor design, including:

  • improving motor efficiency at the different loads and speeds.
  • reducing noise and vibrations of the motor.

To accomplish these tasks, we employ multi-physics simulation, which includes:

  • Structural analysis
  • NVH (noise, vibration and harshness) modeling
  • Electromagnetic modeling of the electric motor
  • Thermal modeling of various solids as well as motor cooling fluid.