COMSOL – the Multiphysics Simulation enabler – has determined means to optimise EV components such as electric motors, batteries, e-powertrains – using its Multiphysics tools to help companies operating in these areas to fastrack product development and reduce cost of physical prototyping.

In a recent webinar session hosted on Autocar Professional on March 23, COMSOL Applications Engineer Dr Utkarsh Chibber took to the topic of ‘Optimisation of EV components with Multiphysics simulation’. Dr Chibber explained how the company’s simulation tools can help analyse electric motors and other electromagnetic components of an EV.

With a case study on the topology optimisation for efficient design for the electric motor of its ID.4 electric car by Volkswagen, wherein the German carmaker intended to minimise the material on the rotor without compromising the structural endurance and power density on offer, he explained how COMSOL’s topology optimisation feature enabled Volkswagen to achieve a novel design and cut down up to 70 percent material used for the same torque capacity of the e-motor.

With such a significant material reduction in the construction of the component, Dr Chibber stressed that the optimisation feature combines coupled electromagnetic and mechanical physics to not only enable making the component lightweight but also aid in savingits overall cost of production. The tool also shows the stresses generated in the rotor in a static-overload analysis of the optimised rotor.

In a second use case from Bosch, COMSOL showcased how the German automotive Tier-1 major leveraged its Multiphysics simulation to design a compact and efficient DC link capacitor that would offer seamless flow of current in an EV. A coupled electromagnetic and thermal analysis which accounts for the skin effects was used to reduce the product development cycle and overall cost of testing. The simulation also eliminates the risk of being unable to measure the temperatures at the right places, and with the ability to place the probe at any point to ascertain the temperature distribution.

The COMSOL Multiphysics Simulation tool also allows for modelling solid conductors, hard and soft magnetic materials, as well as temperature dependency. It also allows for torque calculation in the post-processing phase of the analysis. Dr Chibber explained that the COMSOL Multiphysics Simulation is a finite-element numerical simulation tool that solves partial-differential equations to determine numerical results. “The Multiphysics Simulation tool allows for simulation in a coupled manner – multiple-interacting physical entities – in a model, to capture and mimic real-world performance with extremely-high accuracy,” he said.

The tool also allows for single-physics problem analysis as well as in Multiphysics modelling, starting with a double-physics analysis wherein the two entities can be coupled either in a bi-directional or fully-coupled way. For instance, for motor-vibration analysis – structural and electromagnetic physics are coupled together to ascertain the stress distribution in the motor housing. COMSOL has different modules such as rotor and multi-body dynamics for simulating various rotating components andcapturing their acoustic behaviour as well.

Lithium-ion pack thermal management
The COMSOL Multiphysics Simulation tool also aids the thermal management of Li-ion battery packs implemented in EVs to ensure optimal performance as well as thermal-runaway prevention. Dr Chibber explained that identifying the cause and hot spots inside the pack are very important as li-ion batteries work best within 25-40-degree Celsius temperature range.

He cited a use-case example where Italian automaker Fiat leveraged COMSOL’s battery module and coupled it with the company’s heat-transfer module to determine the surface heat generated by a Li-ion battery pack, and develop a hybrid-vehicle battery pack which is much smaller and compact in nature compared to an EV battery.

According to the COMSOL engineer, the automaker could validate the simulation analysis with actual, real-world testing results, with over 90 percent accuracy. Fiat was also able to reduce the design time by up to 70 percent while identifying the possible dangerous hot spots in the battery pack.

The hour-long knowledge session touched upon various aspects of optimisation of EV components and how the COMSOL Multiphysics Simulation suite can help consider multiple-interacting physics for a holistic analysis.