Thermal Management Unlocks Safety, Dependability, Range, and Longevity for Commercial Electric Vehicles

Humans have designed and built motorized vehicles for more than a century. Deciding which method of propulsion to use did not start as a question about environmental impact, but rather as a pragmatic tradeoff between technical feasibility, availability of the fuel source, and safety. Although electric vehicles (EVs) appeared as early as 1886, most models have been powered by the internal combustion engine (ICE). As the dominant choice for as long as anyone can remember, ICE-powered vehicle technology is mature, rarely presenting novel engineering challenges outside of making the technology cleaner. While more recent innovations such as alternative fuels, exhaust gas recirculation, hybrid drivetrains, and shut-down-on-idle have helped reduce emissions, progress is increasingly marginal. As the transportation industry pivots its substantial engineering resources to EVs, the innovation cycle for EVs is only just accelerating. 

Today, EV propulsion, energy storage, and near-countless incomprehensibly complex microelectronics components are subject to a blinding pace of advancements, inventions, and breakthroughs. With this relentless pursuit of faster, safer, and more efficient technology, vehicle manufacturers don't face marginal engineering decisions, but near-revolutionary ones regularly.

Commercial and specialty vehicle original equipment manufacturers (OEMs) are focused on bringing their all-electric vehicle platforms to market in time to meet strong demand, driven by corporate and government commitments to reducing emissions. States like Washington, for example, have moved to ban all ICE vehicles before 2030, leaving OEMs just eight short years in which to deliver all types of zero-emission commercial fleet vehicles. Furthermore, a growing number have stated their intentions to stop investing in new ICE platforms and models; many more have already defined a specific date to end ICE vehicle production. OEMs now face mounting resource constraints as they design, validate, and ramp production on an entirely new propulsion system – and decide which elements of EV powertrains and their supporting systems should be developed in-house, or outsourced. New electric platforms must meet the range, durability, and reliability required by the commercial vehicle market. Is it possible to spin up multiple new technology teams (software, chemical engineering, and semiconductors, to name a few) in-house in time to meet escalating customer demand?

Similar to ICE engines, but different in profound ways, the impact of ambient operating temperature on electronic components is significant. EVs are chock-full of power electronics and batteries; thermal management (at both ends of the mercury) determines vehicle longevity, performance, and safety. Designing a thermal management system to efficiently manage the thermal loads, and a system that fits the space constraints of a commercial vehicle while reliably meeting the heavy-duty operation environment, requires specialized thermodynamics expertise. 

Anyone who has ever tried to use a smartphone left on a car dashboard on a summer day, or overnight in winter, knows the impact of operating temperature on electronics. So do owners of hydrocarbon-powered cars in Arizona, or Minnesota. For EV owners, however, rather than simply waiting for the temperature extreme to pass (or in the worst case, swapping the battery, heating the engine block, or refilling the radiator), their electronics and batteries are not limited to providing starting power or running vehicle accessories; they are the whole show. Commercial EVs, by definition, must be productive assets. Electronics and battery performance are essential to reliably generating value and getting the job done. Extreme heat and cold can significantly degrade electric powertrain performance, range, and longevity. More profoundly, a catastrophic thermal runaway in batteries (in severe cases) places thermal management at the heart of EV safety, beyond the operator's actions behind the wheel. 

Thermal management in EVs is one of the least visible, but most cutting-edge frontiers in EV transportation. From dissipating heat generated during power conversion and electrochemical processes, to warming components up to the optimal operating range, the right temperature improves performance, longevity, and safety, and enhances battery charging speeds. While many of these issues are, for the most part, problems already solved in EV passenger cars, the inordinately larger workloads and duty cycles of commercial, purpose-built, and off-highway EVs result in correspondingly higher voltages and battery capacities. When combined with the harsher operating conditions of these work vehicles, these technologies cannot simply be scaled up from the passenger car domain. Innovations in efficiently controlling temperatures of EV propulsion components are at the apex of making electrified commercial fleet vehicles viable. Similarly, and perhaps even more so, thermal management will be at the forefront as the industry moves again from EV technology to fuel cells. So, keep an eye on the thermostat in this space.

Gina Bonini is Vice President and General Manager of Advanced Thermal Systems at Modine, which designs, manufactures, and tests heat transfer products for a wide variety of applications and markets.

Modine | www.modineev.com