If you’ve ever sat in an electric vehicle (EV) charging on a frigid highway rest stop or merging onto a busy urban highway, you’ve experienced something the engineers at my team and I think about every single day: the quiet, critical work of thermal interface materials (TIMs) keeping EVs running smoothly. For 12 years, I’ve run a small, specialized TIM supply business—we don’t do mass-market adhesives or random industrial compounds; we make the stuff that stops EV parts from overheating, shorting out, or falling apart before their time. Too many drivers and even some shop techs treat EVs like just fancy gas cars with batteries, but under the hood (or, rather, under all the plastic panels), thermal management isn’t a “nice-to-have”—it’s the backbone of performance, safety, and even how far you can drive on a single charge. Today, I want to walk you through the real, day-to-day applications of our TIMs in EVs, because when a manufacturer calls us at 2 a.m. about a field failure at 20,000 units, there’s almost always a TIM-related angle. Thermal Interface Material
Let’s start with the part that everyone talks about, but almost no one understands the nuances of: the battery pack. I can’t tell you how many times I’ve seen a battery pack labeled “thermal managed” like that’s enough. A typical modern EV battery isn’t one big block of lithium-ion—its hundreds, sometimes thousands, of individual cylindrical, pouch, or prismatic cells stacked tightly together like sardines in a metal tray. When those cells charge, especially fast charge at a public station, and when they discharge hard (like pulling a trailer up a mountain), they generate insane amounts of localized heat. If that heat isn’t moved away evenly, some cells will get way hotter than others—hot enough to degrade faster, develop internal shorts, or in the worst case, trigger thermal runaway. We’ve all seen those viral videos of EV batteries catching fire; most of the time, that’s not a cell defect out of the gate—it’s a gap in heat transfer between the cell and the cooling plate. That’s where our TIMs earn their keep. We don’t just sell a generic paste or pad; we formulate our products to match the exact surface of a pouch cell, which is thin and flexible, or a cylindrical cell’s curved casing. Our soft, high-conductivity thermal pads (our most popular product for battery packs) sit between each layer of cells and the aluminum cooling plate, displacing all the tiny air gaps that form between two rigid metal surfaces when you bolt them together. Air is an insulator, right? So even a 0.1mm gap can reduce heat transfer by 50% or more. Last year, one of our key automotive clients switched to a competitor’s low-cost pad to cut costs, and within six months, they had 1,200 battery packs with 10% faster capacity degradation than projected. We got a call within a week, ran thermal mapping tests, and found their pads were too rigid to compress into the cell surface, leaving air gaps in 20% of the pack. We supplied a custom pad formulation that’s 30% softer, same conductivity, and fixed the issue without adding weight to the pack—something critical, because every extra pound cuts range.
Next up, the power electronics that control the flow of electricity through the car. If the battery is the EV’s energy storage, the power electronics are its brain and nervous system. Think of the inverter, the DC-DC converter, and the on-board charger (OBC) as little furnaces that run 24/7 to adjust voltage, send power from the battery to the motor, or charge the battery when you plug in. A 2022 study from the Institute of Electrical and Electronics Engineers (IEEE) found that power electronics in EVs account for up to 30% of all thermal-related component failures, and 75% of those failures were traced back to poor TIM performance. The inverter, in particular, has switching transistors (IGBTs or MOSFETs) that get so hot under heavy load—like when you’re accelerating from 0 to 60 mph—that they’ll shut down or fail if they can’t shed heat fast enough. These transistors are mounted to a metal heat sink via a thin layer of TIM, and here’s the catch: unlike the battery, the inverter’s components need TIMs that work both at extreme cold (down to -40°F in places like Minnesota or Norway) and extreme heat (up to 125°F under the hood, and higher when the car is working hard). Our product line for power electronics is a two-part silicone-free thermal paste—silicone can outgas over time, which coats transistor surfaces and causes electrical resistance, a no-no in electronics. We formulated our paste with ceramic fillers that have a conductivity of 8 W/mK, which is high enough to move heat away from the IGBTs, but low enough electrical resistance that it doesn’t interfere with the tiny voltage signals running through the transistors. Last winter, a client in Sweden tested our paste against three other leading brands; in a -22°F test chamber, two of the pastes dried out and cracked, leaving gaps between the transistor and heat sink, while ours maintained its flexibility, keeping the thermal resistance steady at 0.04 K·in²/W, well within the manufacturer’s specifications.
Then there’s the traction motor, the part that turns electricity from the battery into the torque that moves the wheels. Most people don’t realize that EV traction motors aren’t as simple as electric fans—they generate a lot of heat in two places: the stator windings and the rotor, especially in high-performance EVs that can hit 150 mph or tow 10,000 pounds. We don’t do much with the core motor itself, but we play a role in the motor’s integrated heat exchanger, which is mounted on the outer casing of the motor to pull heat away. A lot of manufacturers use thermal phase change materials (PCMs) for this application—TIMs that are solid at room temperature, melt at a specific temperature, and absorb large amounts of heat as they change state, then solidify again when they cool down. That’s perfect for traction motors, because they have brief, intense heat spikes when you’re accelerating hard, rather than consistent low heat. Our PCM for motor heat exchangers has a phase change temperature of 105°F, exactly the threshold where most traction motors start to get too hot. When the motor hits that temperature, the PCM melts, absorbing 200 kJ/kg of heat—enough to keep the motor from overheating during a 10-minute full-throttle run—then solidifies quickly once you ease off the gas. We also make a reinforced thermal pad for the motor’s power cable connections; those connections vibrate constantly as the car moves, so ordinary TIMs would wear out after a few years, but our pads have a fiberglass core that makes them tear-resistant, so they stay in place and keep heat moving away from the connection point, which is a common source of electrical fires in EVs.
Wait, I can’t skip over the auxiliary systems—those are the parts that make an EV comfortable and convenient, and they run on the same battery, so they also need careful thermal management. Let’s talk about the on-board charger (OBC) first: when you plug your EV into a 150 kW fast charger, the OBC converts AC power from the grid to DC power to charge the battery, and that conversion generates a lot of heat. If the OBC overheats, it will slow down charging or stop altogether, which is frustrating when you’re on a road trip. We supply high-density thermal pads that fit perfectly into the OBC’s heat sink, often with a metal foil backing that directs heat straight to the cooling fins. One client reported that after switching to our pads, their fast-charging speed increased by 7% at temperatures above 85°F, because the OBC could shed heat faster, instead of throttling power to avoid overheating. Then there’s the cabin climate control system—EVs don’t have a gas engine to waste heat for cabin heating, so they rely on resistive heaters or heat pumps, which also generate heat that needs to be managed. The battery for the 12-volt system and the thermal sensors in the cabin’s HVAC unit both use small surface-mount components that can’t tolerate high heat, so we supply tiny, die-cut thermal pads that fit between these components and their small heat sinks, keeping them cool without adding bulk that would take up space in the tight cabin under-dash area.
But here’s what a lot of people don’t ask me about, even though it’s the fastest-growing application for our TIMs: next-generation EV components, like SiC (silicon carbide) semiconductors and 800V electrical architectures. 800V systems are the new standard for fast charging, because they let you charge a battery from 10% to 80% in 15 to 20 minutes, but they also operate at higher voltages and generate more localized heat than older 400V systems. SiC semiconductors, which are replacing IGBTs in many inverters and OBCs, are smaller and more efficient, but they run hotter—often reaching 175°F under load—than traditional silicon parts. Our latest product, a 12 W/mK boron nitride-filled thermal paste, is specifically formulated for SiC components; it has lower thermal resistance than our old ceramic paste, and it’s non-conductive, so if it squeezes out between components during assembly, it won’t cause a short circuit, a huge concern for manufacturers working with small, tightly packed SiC circuits. We tested this paste with a leading SiC inverter maker last year, and they found that using our paste instead of their previous material reduced inverter temperature by 12°F under full load, and increased component lifespan by an estimated 40%, because the SiC semiconductors weren’t being thermally stressed. This is the cutting edge of our business—most of our R&D budget goes into formulating TIMs that can keep up with new EV technology, because if we fall behind, we get left out of the next generation of vehicles.
Now, let’s talk about the real-world impact of good TIM application, beyond just technical specs. I’ve seen field data from a client that worked with us on their 2021 EV line: they had 50,000 vehicles on the road, and over two years, they reported only 12 battery pack related failures, compared to 217 failures for their competitor’s EV line that used a different TIM. The cost of replacing a single EV battery pack is around $15,000, so that’s a $3.1 million difference in warranty costs for that client in two years. For consumers, that means a lower chance of being stranded with a dead or damaged battery, which is a top concern for people thinking about switching to EVs. It also means better range consistency—if a battery isn’t degraded by uneven heating, it will hold its original range for longer, which is the single biggest factor in EV owner satisfaction.
I won’t lie: this work isn’t without challenges. EV manufacturers are constantly pushing for lighter, more compact components, which means there’s less space for TIMs, so we have to make our products thinner, more conductive, and more flexible, without losing durability. They’re also pushing to lower costs, so we’re always balancing performance with material costs—we can’t make a TIM that’s so expensive it adds $500 to the price of a battery pack, but we also can’t cut corners so much that it fails after 3 years. Another big challenge is the global supply chain for the raw materials we use—ceramic fillers, phase change materials, silicone compounds. Post-pandemic, lead times for some materials are 12 to 18 months, so we keep a 6-month buffer of all our core materials, and we’re actively working with alternative material suppliers to avoid production delays that would hold up our clients’ car launches.
At the end of the day, what I love most about working in TIMs for EVs is that it’s a quiet, behind-the-scenes industry. Most people don’t know what a TIM is, let alone that it’s the difference between a car that drives 200,000 miles without issues and one that has to get its battery replaced early. But every time I get a call from a client saying our product helped them hit a production deadline, or reduced their warranty claims, or made a customer happy with their new EV, I remember why we started this business 12 years ago. The future of EVs isn’t just about bigger batteries or faster chargers—it’s about the tiny, specialized materials that keep all those parts working together, safely and efficiently, for years.
If you’re an EV manufacturer, a tier 1 parts supplier, or a service provider working on next-generation electric vehicles, and you need a thermal interface material partner that understands not just the specs, but the real-world challenges of automotive thermal management, reach out to our team to discuss your project needs and performance requirements.
EMI Material References
- Institute of Electrical and Electronics Engineers (IEEE). (2022). Thermal Management Challenges in Modern Electric Vehicle Power Electronics. IEEE Transactions on Power Electronics, 37(10), 11892-11905.
- International Energy Agency (IEA). (2023). Global EV Outlook: Thermal Management in Electric Vehicles. IEA Publications, Paris, France.
- Society of Automotive Engineers (SAE International). (2021). Thermal Interface Material Performance Standards for Lithium-Ion Battery Packs. SAE J2307, Warrendale, PA.
- Zhang, L., et al. (2022). Phase Change Materials for Traction Motor Thermal Management in Electric Vehicles. Journal of Power Sources, 542, 231678.
- European Automobile Manufacturers Association (ACEA). (2023). Warranty Cost Drivers in Electric Vehicle Manufacturing: A 5-Year Analysis. ACEA Technical Report, Brussels, Belgium.
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