Putting the ‘e’ in eVTOL

For decades, the team at TE Connectivity (TE) has been helping design safe and efficient electrical power management systems for everything from military planes to moon landers. Now TE is supporting a new frontier: the emerging Electric Vertical Takeoff and Landing (eVTOL) industry. 

One of the most crucial yet misunderstood parts of any aircraft is its electrical management system. Whether it sustains avionics, flight controls, landing gear, or in-flight entertainment, the power must keep flowing. 

TE has been a leader in electrical power management and distribution across the aviation/aerospace industry since one of TE’s founders invented the first solderless wiring terminals back in the early 1940s.

“We have a very rich history and are known for providing products that work,” Matt McAlonis, TE technical fellow and global leader of Advanced Systems and Architecture, explains. “We have been involved with electrically powered vehicles for many years, so our design, manufacturing, and testing methods are mature, and the usability and reliability of our products is time-tested.”

“As the eVTOL community emerges, we are leveraging what we have already learned in prior-developed electric propelled vehicles to help designers increase performance, while reducing development times and costs,” he continues. “You can follow the wire from the charger inlet to the battery compartment, to the power switching/distribution area, to the motors, avionics, and communications—TE Connectivity has over 100 products that are developed and available for eVTOL use.”

eVTOLS are not “flying cars.”

The mainstream press has often used the term “flying cars” to describe eVTOLs, and as cool as it sounds, the fact is that electric cars and eVTOLs cannot be compared when it comes to power needs or usage requirements.

While an electric car’s battery will typically drain at a relatively steady rate, an eVTOL’s batteries need varying amounts of power for takeoff, climb, cruise, descent, and hovering. And some of those phases require high bursts of energy. Optimizing all these parameters is extremely challenging from a power management and distribution perspective.

“If an electric car runs out of energy or experiences some other fault in the propulsion system, you can just typically pull over to the side of the road. That’s not the case with an eVTOL,” McAlonis says. “As you discharge the battery’s power, the energy quality diminishes. You must know how to deal with these things to help ensure you have enough reserve power to go into a holding pattern as you approach the airport or landing zone.”

“What does the bottom power threshold look like, and what are the energy reserves required for an eVTOL to operate safely?” he continues. “Those are the things we consider when we design our cables and connectors so there is not a minimalistic resistive load on the battery. Each connectivity node is critical.”

Another big difference between electric ground vehicles and eVTOLs is the weight limitations. When it comes to electrically powered aircraft, every ounce / gram counts. Weight optimization is another area where TE’s unparalleled experience with electrical power distribution benefits designers.

“We can start with our industry standard, aerospace-tested products and use that as our starting point with an eVTOL designer—the things that are already reliable and certified,” McAlonis says. “Then, we enhance the system from there. We can go with shape-optimized wires, lighter materials, and smaller connectors to improve the vehicle’s network’s size, weight, and power.”

“Battery weight is a given,” he continues. “Our task is to cut weight everywhere else while maintaining performance and safety. We have demonstrated we can do that through product design optimization.”

1.21 Gigawatts…

While the goal is to make the aircraft’s power grid as lightweight and efficient as possible, McAlonis stressed that they can never lose sight of the havoc all that power can wreak if it’s not managed safely.

“For vehicles, these are very high-voltage systems. eVTOLs are sometimes orders of magnitude higher than an arc welding machine’s voltage,” he explains. “The failure of any component can be devastating to the aircraft. To provide for safety, we must be extremely conservative in our designs.”

“With eVTOLs, we will have to inspect and maintain cabling as needed, so we need to design circuitry to allow the mechanic to disconnect a power cable safely,” McAlonis says. “We have a high voltage inter-lock (HVIL) circuit that ‘knows’ when a cable gets unplugged and automatically cuts power so the connection is not ‘hot’ to the touch.”

No doubt, moving all that high-voltage electricity efficiently and safely while minimizing parts count and system weight is a daunting task. And if all that was not enough, aircraft designers should consider additional areas that need increased flexibility for wiring and cables. 

"With an airplane, the generator is mounted with the engine on the fuselage or wing, so there is minimal movement in the cables,” Matt continues. “In many eVTOLs, you have articulating motor/propeller designs. That means the cables may have to flex potentially hundreds to thousands of times during a flight. They are small flexes, but it’s critical to design the cables and connectors to significantly reduce fatigue and vibration failure points.” 

These needs are pushing TE to explore beyond the traditional cable materials and constructions and into innovative conductor and jacket materials including the use of aluminum-based alloys for weight optimization, something they have been using in other aerospace applications for a long time.

Cutting-edge solutions…

McAlonis says that while many companies are put off by the eVTOL industry’s vast array of challenges and limitations, TE’s global team of problem solvers are excited by the opportunity to use their decades of experience to find solutions and help energize this emerging, society-changing opportunity. 

“An important thing to understand is that we are working with customers who are in the lead position in the eVTOL market, and they need time and cost reduction. If we can standardize the products we already have, they do not have to be reinvented for every application,” he explains. 

“We have a wealth of experience with FAA certification requirements and meeting specialized testing requirements for things like flammability, smoke, and toxicity. Cars and trucks do not have those requirements, but they are critical for eVTOL certification.”

“Our Advanced Systems and Architecture team has subject matter experts from our various product streams available to work with customers to help identify the best products and solutions for their needs,” McAlonis says. “We have the expertise, proven product, and experience to help shorten eVTOL development time and costs.”

“When it comes to a low-risk solution, there is no need to go anywhere else for power management than the aviation experts at TE,” McAlonis says.