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FEATURE
ELECTRICAL & ELECTRONIC COMPONENTS Keeping eV components cool in harsh enVironments
The role of electric vehicles in harsh and potentially dangerous environments is growing. Steve Hughes, managing director of REO UK, looks into the role liquid cooling systems play in preparing these vehicles for their applications
A
ccording to the Society of Motor Manufacturers and Traders (SMMT), 23,480 passenger plug-in cars were registered
in the UK in January 2022, 90% more than last year. If we include nearly 13,500 non-chargeable hybrids, nearly a third of new cars are electrified. But with the market growing, it is inevitable that we will see more EVs being used in harsh and hazardous environments as we reduce our reliance on traditional ICE vehicles. Despite EV technology evolving, harsh
environments such as those with high temperatures can affect the functioning of chargers and reduce the lifetime of vehicles. Plus, environmental conditions like dust and debris can have a negative impact on the power electronics of batteries and chargers. There has recently been a rise in the number
of electrified and battery-powered explosion-proof vehicles. Unlike ICE counterparts, these avoid ignition risks in the surrounding atmosphere, reducing the likelihood of explosions. Therefore, there is now a growing gap in the market for explosion-proof trucks and vehicles in ATEX
environments like oil and gas processing plants, mining facilities and chemical plants. Like ICE vehicles, EVs can be used for
maintenance, logistics, first aid, surveillance and firefighting purposes. They will mainly use AC motors with high torque and gradual power distribution, preventing the risk of sliding or poor grip on sandy, snowy and icy terrains. These vehicles also have specific safety features covering electrical components like the batteries and connectors, as well as non-electric parts that could generate high temperatures or sparks, such as the brakes.
Cooling solutions
Every electric car battery needs a cooling system. Generally, lithium-ion batteries operate best between 20-40˚C, so operating outside this range requires an appropriate cooling system to facilitate heat dissipation. Most electric vehicles use a cooling loop containing an ethylene glycol coolant, which is circulated through the batteries via an electric pump. When relying on air cooling and fans, vehicles are at risk of dust and other debris entering through the vents and causing damage. As demand for EVs grows in ATEX and other extreme environments, design engineers and vehicle manufacturers can expand their applications by incorporating liquid cooling systems from the beginning. Transferring heat from the
engine components using liquids such as water can provide effective heat dissipation without potentially harmful particles entering the system. Meanwhile,
2 DESIGN SOLUTIONS JULY/AUGUST 2022 4
an internal thermal switch can be used to execute a safe and controlled shutdown of the system if the coolant runs out or the cooling system fails.
Braking resistors
Another area of importance is braking resistors, which protect the electric motors from voltage rises in the DC link. No resistor is the same, and heavy vehicles and trucks need high wattage braking power and effective heat dissipation to maintain driver safety when they brake sharply. Installing water-cooled braking resistors is
a vital step before bringing these vehicles into more arduous settings, whether these are processing plants or oil and gas facilities. To help meet this demand, we recently began supplying the BWD 158 standard range, which is rated for continuous power of up to 5,000W. It has a high overload capacity – up to 33kW – and a low surface temperature, which can be lower than the ambient temperature in certain environments. Therefore, this new product lends itself to operation in ATEX environments, where a high possibility of explosion necessitates low surface temperatures. As EVs overtake traditional ICE vehicles,
their role in ATEX and other potentially hazardous environments will only increase. Preparing these vehicles for challenging surroundings like processing plants means starting at the design phase and specifying a liquid cooling system to shield the battery and other electrical components from the effects of extreme heat and debris. Integrating water- cooled braking resistors can also help ensure driver safety in the most difficult of terrains.
REO UK T: 01588 673411
www.reo.co.uk
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