2 Ways EV Manufacturers Can Enhance NVH Performance
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- Jul 11, 2019
2 Ways EV Manufacturers Are Enhancing NVH Performance (UPDATED)
Last updated 8/14/26
Electric vehicles have eliminated the engine noise that once masked cabin sounds, and that's created a new problem. Wind, road vibration, and component hum that went unnoticed in a combustion vehicle are now front and center in an EV.
For manufacturers, achieving the quiet, refined ride customers expect means solving a tough engineering paradox: the lightweighting strategies that make EVs efficient are the same ones that make NVH harder to control. Thinner panels, fewer welds, and more panel holes all help cut weight, and all compromise acoustic performance.
The good news is that two relatively simple material solutions, rubber panel plugs and butyl damping patches, can help you reclaim that performance without giving back the weight savings you worked for.
Optimizing Panel Plug Plugs for NVH Performance
EPDM is one of the top rubber materials for improving NVH resistance in automotive applications due to its ability to absorb sound and vibration, great tensile strength, water swell resistance, and its ability to withstand to environmental conditions, such as high temperatures and UV resistance.
Panel Plug Optimization Points
The core elements that need to be optimized for an ideal EPDM panel plug include:
Thickness: While making the plug thicker will enhance a vehicle’s NVH performance, it will also make it heavier and more expensive due to increased material. You’ll need to find the perfect balance for your application and needs. This can be determined by using a formula that calculates the noise transmission loss through the surrounding panel.
Rubber Durometer will be a factor and must be balanced with the design of the plug. A higher durometer will have improved NVH resistance due to higher density, and vice versa for a softer durometer. The drawback to a higher durometer is that it also weighs more. EV manufacturers should usually stick with right around 60-65 durometer for their plugs in order to maintain optimal sealing and NVH qualities.
The 60–65 Shore A durometer range hits a practical sweet spot for most EV panel plug applications. Below 60 Duro, a plug becomes too soft to maintain a reliable seal under the thermal cycling and vibration loads an EV body experiences over its lifetime; you risk gaps forming that let noise and moisture in. Above 65 Duro, the rubber gets stiff enough that it starts transmitting vibration rather than absorbing it, which defeats the purpose. It also becomes harder to install consistently on a fast-moving assembly line, increasing the chance of improper seating.
At 60–65, you get a plug that conforms well to panel variations, installs reliably by hand, holds its seal across temperature extremes, and still has enough density to meaningfully attenuate sound transmission through the hole it's covering.
Butyl Damping for Panel Holes
Electric vehicles have a significant number of panel holes throughout their body/chassis, as this helps reduce the overall weight, improve battery efficiency, and allow e-coat, surface prep, and primer to drain from the cavities during production. The problem that they pose for EV manufacturers is the amount of noise they allow through. This is where butyl rubber solutions come into play.
Balancing Butyl Thickness
If you're an NVH Engineer, the area where you'll want to pay the most attention to here is the amount of butyl adhesive being used. The more you use, the better it will perform with reducing noise from entering the vehicle’s cabin. But, you also have to balance it with weight so that you don’t lose the lightweighting benefit of panel holes.
Butyl Manufacturing Quick Tip:
Another aspect of Butyl that’s easy to overlook is designing and manufacturing the product for assembly, or DFA (Design-for-Assembly). One way you can improve your manufacturing efficiency is by switching from sheets to rolls.
Switching from sheets of 8-12 butyl foil patches to rolls of them. Sheets cause 2 assembly issues. First, the butyl will most likely stick to the sheet below, resulting in unnecessary time spent separating the two. The other problem is that the assembly worker will have to constantly stop after every 8-12 patches in order to grab the next one.
Custom Butyl Formulations for Assembly Process
Not all butyl is created equal. Echo's proprietary EchoLoc™ formulation was developed with the realities of high-speed assembly in mind. It gives workers a five-minute window to remove and reposition a patch without leaving residue, a small but significant advantage when mistakes on a fast-moving line are costly. Adhesion then strengthens progressively over the following hour, resulting in a final seal that's just as reliable as a traditional butyl application. For manufacturers looking to reduce rework and improve assembly efficiency without compromising acoustic performance, EchoLoc™ offers a practical edge.
Conclusion
Enhancing NVH performance continues to become a more and more prevalent topic as EVs continue to increase in demand. In order to accomplish this, OEMs and Tier 1s need to look into the granular details of products that didn't change much during the ICE era. With more EV startups popping up more than ever, the manufacturer that is able to produce the best experience by decreasing NVH, while also making their manufacturing more efficient, will most likely be the one that comes out on top.
Outside of the EV market, typical plugs used in your fossil fuel cars are outdated & must be updated to meet the high demand for quiet and comfort. Echo is engaged in helping our customers design the best high-performance NVH plug within any budget & here is how. Specially formulated Butyl foil & specially designed panel plugs help keep noise & cost down while taking into consideration ergonomics & all while meeting force requirements set by the industry leaders. NVH in the mobility industry is being taken to a new level.
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