Electrification is advancing rapidly across transportation, but scaling what works in passenger cars for trucks, buses, and off-road vehicles is far too simplistic for the complex demands of heavy-duty platforms. These platforms introduce weight, exposure, and lifetime challenges that force engineers to rethink nearly every component (Figure 1).
“The vehicles in this market are often much larger and heavier than passenger cars and, therefore, require much greater electrical energy,” explains Daniel Domke, product manager, E-mobility Industrial and Commercial Vehicles, with TE Connectivity. “Their components also face additional risks.”
Figure 1. System layout of a heavy-duty electric truck showing distributed components including the inverter, motor, PDU, and battery system. This distributed design is necessary when centralization is impractical due to vehicle size and weight.
Passenger and heavy-duty electric vehicles (EVs) may share many of the same core components, including power electronics, electric motors, and batteries, but their size, capabilities, operating environments, and use cases differ significantly.
“The majority of the components in a passenger EV are safely encapsulated under plastic coverings. That’s not the case for large transport trucks or off-road machines, where the connectors and cables are typically exposed and visible to the outside,” shares Domke. “This means that their requirements for mechanical robustness are much, much higher.”
Most heavy-duty vehicles are also exposed to harsher road conditions and environmental factors. “Think moisture, salt, gravel, dirt… all of which can easily reach the inner components of larger vehicles,” he says. “They also usually undergo repeated high-pressure washes, so it’s extremely important to ensure that water isn’t forced or pushed into the connectors.”
Another significant risk factor is the workload. Where a personal vehicle may travel 200,000 miles in its lifetime, mostly shielded under molded plastic covers, a logistics truck, by contrast, can log millions of miles while exposed daily to salt spray, gravel impact, and weather (Figure 2).
“For commercial vehicles, a higher lifetime mileage and uptime are almost always expected. It reflects a company’s business, unlike most passenger cars, which are for personal use.”
Figure 2. HIVONEX connectors from TE are designed to ensure vibration-resistant connections for heavy-duty electric vehicles, engineered to withstand gravel impact, salt spray, and repeated pressure washing.
This divergence only adds to the complexity of engineering decisions. Heavy-duty vehicles require larger batteries and higher current capacity, but their sheer size makes it challenging to centralize electronics effectively. In automotive design, centralization refers to consolidating multiple control functions into one or a few large computing units, rather than dozens of smaller modules.
“In passenger cars, it’s common to centralize functions, essentially putting most applications into one powerful control unit,” Domke notes. “That’s not always possible in large trucks. The vehicle is simply too big and too heavy. Instead, applications must be distributed across the vehicle to keep systems manageable and serviceable. Otherwise, repair and maintenance become nearly impossible.”
Stressors and standards
On paper, the same safety standards apply across passenger and heavy-duty EVs. Connectors must be touch-safe, insulation must withstand voltage, and systems must operate safely under fault.
However, for heavy-duty platforms, these requirements become stricter in terms of duration and scope due to harsher operating environments and longer service lifetimes.
“The general standards are the same, regardless of the type of vehicle,” he says. “But when it comes to lifetime testing, corrosion around interfaces is a critical measure. Here, the timeline is very different for testing between a commercial and a passenger vehicle because the exposure to the environment is also very different.”
While the basic performance requirements are comparable, the test cycles for heavy-duty platforms must simulate years of constant punishment, far exceeding those of passenger cars. “For example, water ingress is a critical one,” Domke adds. “Then vibration is something we have to test.”
Real-world testing must reflect vibration on rough terrain, repeated impacts from gravel, long- term salt corrosion, and even the force of pressure washers used during cleaning.
Figure 3. This heavy-duty charging inlet is engineered for high-voltage EV platforms, where exposure to harsh environments demands rugged, sealed interfaces.
“But there are always specifics to account for. Take gravel bombardment, for instance,” he says. “If you’re driving off-road with a truck, gravel can reach the connectors and break them. You wouldn’t typically experience this in a passenger car. So, there are always additions within the basic standards to consider.”
It’s also not uncommon for OEMs to push beyond established requirements, specifying harsher salt concentrations, longer corrosion cycles, or unique durability benchmarks that reflect the real-world conditions their fleets face (Figure 3).
“Standards are an incredibly important guideline for us, and customers will often add their own custom expectations,” Domke says.
Managing mass
Beyond exposure and uptime, electrified commercial vehicles face a fundamental challenge that’s greater than passenger EVs: mass. Heavy trucks and buses are designed to carry substantial payloads, but electrification adds another layer of complexity.
The heavier the vehicle, the more energy the battery must supply, which in turn can require an even larger, heavier battery. Breaking that cycle means keeping the vehicle itself as light as possible (Figure 4).
“On the commercial vehicle side, people often think there’s plenty of space, so weight is less of a concern,” he says. “But that’s not the case. Every kilogram increases energy demand. With batteries, weight always matters, so the vehicle itself needs to become as light as possible.”
Figure 4. Illustration of a medium-duty electric truck with distributed battery packs, highlighting the packaging and serviceability challenges unique to heavy commercial platforms.
That focus on reducing mass feeds directly into thermal management and materials innovation. Lighter components reduce overall energy demand, but they also introduce new challenges in how heat is generated and dissipated across the system. Smaller conductors, for example, have higher electrical resistance, which creates more heat during operation. If that heat rises beyond certain limits, insulation can degrade, connectors can lose reliability, and efficiency drops.
“We are reducing copper cables to smaller wire gauges, but that means in terms of thermal behavior, we still need to make sure they do not cross a certain boundary,” Domke says.
That boundary refers to the maximum safe operating temperature for the cable and insulation under peak current loads. “So, we use a combination of copper cables and fluid for active cooling.”
At the same time, OEMs are experimenting with different materials.
“There’s a trend to look into aluminum cables,” Domke says. “Conductivity is a bit less, but they’re lightweight. We can increase their size and still come out lighter than traditional copper cables.”
Aluminum is attractive because it offers weight and cost benefits. While it requires a larger cross-section to carry the same current as copper, the overall system weight can still be reduced significantly, which is critical in electrified heavy-duty platforms. Ultimately, this shift requires balancing trade-offs.
Larger aluminum conductors reduce electrical losses but are easier to handle from a weight perspective; copper remains more efficient but is heavier and generates more heat per unit of mass. OEMs are also experimenting with hybrid cable designs, advanced insulation, and alternative alloys. These solutions strike a balance between electrical performance, durability, and lifetime weight savings.
“OEMs are heavily investing in innovation and different raw materials, compositions that will still survive for their lifetime and spark developments in different regions with different engineering teams,” he says.
An evolving market The technical complexity is matched by the pace of change in the commercial vehicle market. “The market situation has changed significantly from ten years back,” Domke reflects. “Back then, everything was settled, and we knew exactly which OEM would come with their next platform in each region. With electrification, everything has changed. Competitors are coming together, creating new use cases for the end customer. For us, it’s important to understand not only what is happening today, but what is possibly coming tomorrow, because development cycles are getting shorter.”
While electrification in heavy-duty platforms is still advancing, Domke emphasizes that e- mobility has matured into a proven technology.
“E-mobility somehow carries a lot of myths from the past, as if it’s a decision of emotions,” he says. “That’s no longer the case. E-mobility is a mature technology. It is competitive, and it answers critical environmental questions for the future. That’s why it’s wise to educate people that this is a valid alternative to the historic combustion engine.”
Filed Under: Electrification, FAQs, Featured, Featured Contributions