Digital tools turn down the heat on EV cooling systems

Managing heat has always been important for road vehicles. When operation depends on a fuel burning there’s obviously a need to handle the heat generated by the combustion. For more than a century, the main method of dissipating that heat and preventing it from damaging the engine has been to transfer it into a cooling fluid circulating around the engine and allow it to escape to the outside world via the radiator.

Over the past decade, however, the increasing use of electric motors has begun to present a new set of challenges. While cooling is still needed, the demands of electric power are different: most notably, the performance and safe operation of the lithium-ion batteries that dominate automotive applications is critically dependent on thermal management. Batteries’ ability to store and release energy is at its best within a fairly narrow range of temperatures, but they become hotter in operation and require cooling to prevent fires.

Optimise use of energy

“A big part of thermal management development goes into the optimisation of energy usage to reduce battery consumption as range anxiety will continue to be an issue at least in the near future,” explain aerodynamicist Kevin Chow and electromobility manager Osoko Shonda, of automotive engineering and development consultancy Horiba Mira. They will be speaking at a conference on vehicle thermal management organised by IMechE at the British Motor Museum in Warwick in June.

In an email exchange with this magazine they explain that thermal management is a critical factor in ensuring that battery-powered vehicles meet their users’ expectations. However, this isn’t the only focus of thermal management research, they add. While people need to know that their vehicle will get them as far as they need to go, they also want to be comfortable. 

“There is a lot of research into the wider vehicle thermal systems that come under this umbrella of energy optimisation. For example, the cabin systems are large consumers of energy outside of spring/autumn due to heating or cooling demands, and research is ongoing into more energy-efficient methods of achieving the same level of perceived thermal ‘comfort’ without the current level of energy consumption,” Shonda and Chow explain.

Some manufacturers are looking into using heat pumps to manage cabin conditions, but these add complexity and parts count, and, as electrical components are still relatively expensive compared to conventional vehicle systems, they also add cost.

The tools used for developing thermal management, in common with almost every technology, are increasingly becoming digital. Simulation and modelling increasingly cross over with thermal management. “Thermal engineers have to anticipate the achievement of the system’s performance prior to physical testing.”  

Predictive modelling

One important advance has been the ability to couple together a 3D model of the vehicle interior with a model of the thermal management system, allowing them to predict the temperature at any point in the cabin under a set of conditions combining exterior ambient temperature with available power from the batteries and settings selected by the vehicle occupants, they explain.

For some vehicles, manufacturers are considering combining battery power with fuel cells, giving the option of using hydrogen as an energy carrier for on-board electricity generation. This will create a new set of challenges. 

The Vehicle Thermal Management Systems Conference and Exhibition will take place on
5-6 June at the British Motor Museum in Warwick.

Want the best engineering stories delivered straight to your inbox? The Professional Engineering newsletter gives you vital updates on the most cutting-edge engineering and exciting new job opportunities. To sign up, click here.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.