Connector System Handles the Heat of EV Charging

A new smaller, thermally efficient terminal connector system enables electric vehicles to handle the high-power loads of charging while potentially reducing the size, weight, and cost of on-board cabling. The HC-Stak system uses a unique, scalable connector design to reduce size and weight by 20% to 30%, while simultaneously managing the heat associated with high-current, DC fast-charging.

“When you deal with that much power, everything typically gets bigger,” Jeremy Patterson, director of engineering for hybrid and electric mobility solutions at TE Connectivity, told Design News at last week’s Battery Show. “But this simple design gives us the ability to handle the space and the heat quite a bit better.”

The new design, which is already being employed on the Tesla Model 3 electric car, could be significant because it enables vehicle engineers to use aluminum cabling. Aluminum is drawing interest among EV makers because it’s lighter and less costly than copper. Some have hesitated to use it, however, because it doesn’t manage heat as well as copper.

The HC-Stak could change that because it more effectively manages the heat that would otherwise be transmitted into the aluminum cable. It accomplishes that through the use of a relatively simple, fork-style contact that contains more copper than conventional terminal connections. The additional copper enables it to dissipate the heat of high-current loads without the need to eat up more space and add more weight inside the vehicle. Moreover, the system is scalable; It can use more forks to boost its current-carrying capability.

“The design gives us more parallel paths, more copper, and therefore better thermal management within the connector,” Patterson told us.

The company’s product line includes two HC-Stak connectors. The HC-Stak 25 offers 257A continuous at 85°C and can be used for electric vehicle motors and battery packs. The HC-Stak 35 is rated at 400A continuous and can be employed in DC fast-charge applications.

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TE Connectivity engineers believe the new technology will have broad appeal inside and outside the auto industry. They foresee it being used on board vehicles for inverters, motors, batteries, heaters, and air conditioner connections. They also see it being used in aerospace, defense, and stationary grid storage.

The biggest application, however, will be electric and hybrid vehicles, Patterson said. “EVs are all about size and weight,” he told us. “This gives engineers the flexibility to use whatever kind of cabling they want.”

Senior technical editor Chuck Murray has been writing about technology for 34 years. He joined Design News in 1987, and has covered electronics, automation, fluid power, and auto.