Close Menu

Improving Electric Drive Module Efficiency with Reliable Pressure Relief Valves


A major automotive manufacturer faced a significant setback when working on a new design for their Electric Drive Module (EDM). When in-house pressure relief valves failed to repeatably crack open under various pressure conditions, the manufacturer searched for an outside solution to ensure project and product success.



When designing an EDM for their new electric vehicle fleet, a leading automaker struggled to produce a high flowing pressure relief valve (PRV) that could reliably control oil flow for demand-based cooling and lubrication. Their in-house poppet-style valve cracked open unreliably and could not meet the precise pressure requirements needed for the application. With a planned design freeze occurring in just one month’s time, the OEM looked to The Lee Company to provide a production intent solution in order to offset scheduling delays and get their EDM back on track.



The Lee engineering team met with the OEM to discuss their challenges and devise an appropriate solution utilizing our field-proven high flow pressure relief valves.

In order to maintain pump efficiencies within their EDM, the OEM needed a pressure relief valve (PRV) that could remain completely closed under normal operation to allow the pump to run efficiently at a lower flow rate, then crack open in a tight pressure band to provide cooling to a secondary surge flow loop. They also required a flexible fluid control solution to accommodate multiple EDM design variants and battery electric vehicle (BEV) platforms.


855 LC2 Insert Check Valve

The 855 LC2 Series Pressure Relief Valve is constructed of stainless steel with a high quality metal to metal seal, providing low leakage, long life, and repeatable cracking pressure.

The OEM’s next-generation EDM technology required sophisticated fluid controls to ensure the efficiency of their systems. Lee engineers endeavored to design, build, and deliver a tailored solution that exceeded the customer’s expectations for utility, performance, and quality – and their accelerated timelines. The winning design was a variant of the 855 LC2 Series Pressure Relief Valve, Forward Flow tailored specifically to accommodate the application’s required tolerances for pressure and flow rate. As a part of our expansive catalog of commercial-off-the-shelf (COTS) precision fluid control products, this valve provided a perfect customization baseline due to its fast response, high flow capacity, and highly repeatable cracking pressures.


Histogram of cracking pressure test data from multiple pressure relief valves used within this EDM.

Cracking pressure specifications were of critical importance to the OEM as it directly impacted the efficiency of the EDM. While the requested tolerances were tighter than our standard pressure relief valves – with a tolerance of 5% as compared to the 15% that is typical for this valve – we were able to modify the valve to help achieve the desired cracking pressures.

The OEM integrated The Lee Company’s pressure relief valve into two initial EDM design variants, totaling hundreds of thousands of valves per year. The pressure relief valves utilized in each design work to divide flow within the EDM.

Standard Flow Curve 855 LC2 Series Pressure Relief Valve

Standard flow curve for the 855 LC2 Series Pressure Relief Valve.

At The Lee Company, we’ve supplied a vast range of miniature components that have been field-proven in millions of vehicles around the world. Due to our experience in the automotive industry and extensive catalog of proven COTS products, the OEM could trust in our engineered solution. They no longer needed to waste time and in-house resources to design, verify, build, and test miniature hydraulic components to solve their problems. By choosing The Lee Company, the OEM received a 100% functionally tested solution in a single assembly. Our degreed sales engineers provided an innovative technical solution to the OEM’s complex fluidic problem, setting them up for future success in their EDM design.


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.



From emerging news to helpful resources and industry insights, we’re here to help you stay up to date on everything fluid control.