INDUSTRY FOCUS - AUTOMOTIVE ELECTRONICS
Bringing the cool to EV charging
Steve Drumm, strategic marketing manager – solutions in energy, OMRON Electronic Components Europe B.V., explains how consumer, commercial and industrial AC EV chargers can get cooler, smaller and longer lasting.
EV-charger design challenges The ongoing shift toward electrification holds the promise of cleaner and more energy-efficient living. On the other hand, end-user expectations continue to drive demand for more compact equipment that fits neatly and stylishly into lives and living spaces while also delivering higher performance. These demands for smaller, slimmer and faster apply to everything, from accessories and small appliances to power adapters and chargers including electric vehicle service equipment (EVSE). High-power EVSE wallboxes are an increasingly common sight in today’s homes and businesses. These support Mode 3 charging, which stipulates built-in control and protection functions for safety, and can charge an EV at up to 22kW from a three- phase AC supply. By providing convenient access to safe and secure charging, ideal for use overnight or during the working day, these wallboxes can certainly help dispel the speed of charge and range anxiety often
dissipation within the enclosure is undesirable, of course, and also mitigates against achieving slimmer and more compact wallbox designs.
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cited as the main reasons for motorists’ reluctance to adopt EVs as daily transport. On the other hand, size and aesthetics are highly important and become a key differentiator between manufacturers. However, cramming the circuitry into the smallest and thinnest possible enclosure brings thermal management challenges that must be addressed to ensure the long- term reliability of the EVSE as well as user safety.
” 32 OCTOBER 2025 | ELECTRONICS FOR ENGINEERS
Excessive heat
Wallboxes like these could be in continuous use or may be connected to several vehicles in rapid succession, especially when installed in a workplace scenario, giving little or no opportunity to cool down between charges. In direct sunlight, the internal temperature can easily reach 70-80˚C, and cycle through 50-60˚C variances within the space of a couple of hours.
While units equipped with temperature sensors can throttle the charging current in overtemperature conditions, which is good for safety, this means slower charging rates and less convenience for the end user. On a particularly hot day, or if a fault is causing the wallbox to overheat, the charger may not be able to function at all. Addressing these thermal challenges can enhance reliability, safety and the user experience.
Self-heating effects Within the wallbox circuitry, resistive components, power transistors, inductors, transformer windings, cables and
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