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Helping a Leading EV Manufacturer Prevent Catastrophic System Failure in their EDM

A leading electric vehicle manufacturer faced a significant obstacle when working on a design for their new powertrain series. They found that cup plugs used to seal cross-drilled holes in their Electric Drive Module (EDM) were dripping the required sealant into their assembly, causing catastrophic system failure. The manufacturer needed a better fluid control solution — and fast.


When designing a new powertrain series for their electric vehicle fleet, a leading electric vehicle automaker discovered serious manufacturing and leakage issues with the cup plugs (or “freeze plugs”) used throughout their EDM. These plugs required Loctite® to seal and hold them in place – a step which added up to an hour of curing downtime and increased manufacturing risk by further complicating the installation process. If sealant is not used, these plugs are prone to leakage, as the interference fit requires holes that are machined with a very high level of precision and an installation process that must hold tight tolerances for alignment and stroke. After testing, the OEM found putting too much Loctite on the plug during installation caused the sealant to drip down into the manifold in one particular location, resulting in complete system failure that rendered the EDM unusable. In order to replace the cup plugs used in this particular location, they turned to The Lee Company for a field-proven fluid control solution.


Lee Engineers met with the OEM to discuss their current challenges and devise an appropriate solution utilizing our industry-leading expansion plugs. In order to ensure system reliability throughout their EDM and reduce manufacturing headaches, the automaker needed a plug that both guaranteed leak-free performance and was easily installable.

Quickly, the 18 mm Short Betaplug® emerged as the ideal solution. The Betaplug is a pre-assembled, tapered expansion plug engineered to seal cross-drilled holes in plastic or metal housings without the need for threads, O-rings, or sealants. Using the Lee Controlled Expansion Principle to ensure retention, this plug provides a 100% leak-tight metal-to-metal seal and can accommodate a wide variety of diameters and pressure ratings. The single-assembly design helps to facilitate reliable automated or manual installation and is cost-effective for mass production.

Expansion Plug Series Rated Pressure Expansion Plug Diameter Maximum Sealable Passageway Expansion Plug Length Expansion Plug Material Acceptable Housing Material*
Short Betaplug® 35 bar 5 – 20 mm 4.5 – 19.32 mm 8.57 – 12.62 mm Aluminum Aluminum, Cast Iron, Stainless Steel, or Steel
DL Series Plug 69 bar 4 – 8 mm 3.3 – 7.2 mm 3.0 mm Stainless Steel Aluminum
6000 Series Betaplug® 276 bar 7 – 8 mm 6.5 – 7.3 mm 11.69 – 13.08 mm Aluminum Aluminum, Cast Iron, Plastic, Stainless Steel, or Steel
6000 Series Betaplug® 483 bar 4 – 6 mm 3.6 – 5.5 mm 8.00 – 10.29 mm Aluminum Aluminum, Cast Iron, Plastic, Stainless Steel, or Steel

*Expansion plugs can be used in other housing materials. In order to find the appropriate solution for your specific application, review with your local Lee Sales Engineer.


The Lee Company offers an assortment of expansion plugs rated for different pressures, sizes, and materials, which meant the OEM could select the right component for their specific needs.

The OEM integrated the Short Betaplug into one key area of the EDM for the lifetime of their EV powertrain series. Because the Betaplug is a leak-tight component that is both easy to install and does not require the use of a sealant, the OEM was able to stop the unintended drippage while also reducing manufacturing costs and scrap caused by failed or leaking cup plugs. With this innovative solution, they simplified their manufacturing process and eliminated the need for tedious curing downtime in this portion of the system.

The matching tapers of the Betaplug and its installation hole create a perfect fit, eliminating air gaps and the need for additional expansion. This helps to create evenly distributed and known forces on the housing, which is ideal for brittle materials or thin wall conditions. Installation is simple and repeatable.

The Lee Company offers a proven track record for engineering precision components and solving unique problems for major auto manufacturers and OEMs. With over 500 million plugs sold worldwide, the Betaplug applies our market-leading design heritage in the aerospace industry to the unique concerns of the automotive market. This experience meant that the OEM could feel confident in the engineered solution provided to them. By choosing The Lee Company, the OEM received a 100% functionally-tested and cost-effective component that solved their urgent fluid control problem, helping to streamline their manufacturing process, increase their efficiency, and reduce the cost to produce their EDM overall.



For more than 75 years, The Lee Company has been a leading supplier of miniature, precision fluid control products to a wide range of industries including automotive, diagnostics, medical equipment, scientific instruments, aerospace, oil & gas, and off-highway equipment. Lee products are recognized worldwide for superior quality, reliability, and performance. If you are searching for a fluid control component for your EV application or other new vehicle technology and would like to learn more about products offered by The Lee Company, click here or contact a Lee Sales Engineer today.

*Loctite® is a registered trademark of Henkel AG & Company KGaA.



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