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ST Unveils High-Efficiency Contactor for Smooth EV Voltage Transition

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Key Takeaways

  • ST launched its High Efficiency Contactor to enable smooth 400V and 800V EV battery transitions.
  • The HEC supports battery balancing, limp-home mode and safe isolation of dual 400V battery packs.
  • ST's HEC design eliminates incorrect switching risks and supports V2G, MW charging and NACS systems.

Sensata Technologies Holding plc ((ST - Free Report) ) recently introduced High Efficiency Contactor (HEC), a cutting-edge solution designed to simplify voltage transitions from 400V to 800V electric vehicle (EV) architectures while enhancing system reliability, safety and efficiency. EV makers are shifting to 800V systems for faster charging, but most chargers today still use 400V. So, vehicles must work with both systems, creating a key challenge in the EV ecosystem.

ST’s HEC addresses this issue by enabling seamless battery reconfiguration between 400V and 800V systems, allowing EVs to efficiently interface with both old and new charging standards without compromise. Modern EVs often utilize dual battery packs for increased capacity and modularity. However, this poses challenges such as imbalances due to pack aging, uneven usage, or even failures in one of the packs, which can compromise vehicle performance or immobilize the vehicle entirely.

ST’s HEC is engineered to independently access and isolate either of the two 400V packs, enabling features like battery balancing and limp-home mode. This selective access functionality boosts battery longevity, enhances reliability in fault scenarios and improves overall vehicle reliability, a significant advantage for both end users and fleet operators.

It also takes a hardware-centric safety approach by integrating three high-voltage contactor poles into a patent-pending design with mechanically synchronized contacts. This mechanical interlock ensures that only valid switching configurations are physically possible, eliminating the risk of incorrect switching due to software bugs, welded contacts, or mechanical shock. This creates a safer system that lowers the risk of serious faults and supports top safety and reliability standards.

Key Capabilities of ST’s HEC

The system offers flexible configuration, supporting standard battery setups like Series-800V, Parallel-400V and Open-Isolated, along with single-pack options (A-only / B-only) for battery balancing and limp-home modes. Its inherently safe mechanical design prevents incorrect switching, removing the risk of short circuits.

Built for robust performance, it can handle short-circuit events up to 25 kA and withstand mechanical shocks of more than 90g. The compact and lightweight form reduces system components by more than 50%, requiring no extra cooling or special equipment. Additionally, its bi-stable design needs no holding power, and the ultra-low contact resistance (under 50 µΩ) ensures high efficiency by minimizing energy loss and heat.

Designed for demanding, safety-focused applications, the HEC handles continuous currents above 1000 A. It includes a built-in ASIL-D compliant position sensor for real-time diagnostics. In addition to enabling 400V/800V battery switching, Sensata’s HEC works with Vehicle-to-Grid (V2G) setups, Megawatt (MW) charging and the North American Charging Standard (NACS/J3400), making it a flexible and future-ready solution for today’s EV and energy systems.

As EVs continue to evolve, infrastructure constraints, safety concerns and system inefficiencies have the potential to slow down its adoption. Sensata’s HEC is poised to address these barriers, enabling a smooth and safe transition to 800V architectures, extending vehicle reliability and simplifying battery system integration.

ST Gains From Strong Portfolio, Macro Woes Persist

Sensata boasts a rich portfolio of high-voltage protection and battery management systems. It is also well-positioned with a diverse portfolio of high-value products. This includes a robust ICE portfolio, electrification opportunities for auto and HVOR, and advanced sensing and electrical protection solutions for industrial and aerospace customers.

In June 2025, ST’s subsidiary, Dynapower, introduced the MV Integrated PowerSkid — a cutting-edge solution designed to simplify and strengthen medium-voltage energy systems across key sectors like renewables, battery energy storage systems, data centers and green hydrogen.

Nonetheless, the company is dealing with challenges from global economic uncertainty and changing trade policies. It also highlighted a temporary gap between paying tariffs and recovering those costs, which may negatively impact its quarterly performance.

ST’s Zacks Rank & Stock Price Performance

ST currently carries a Zacks Rank #2 (Buy). Shares of the company have lost 19% in the past year against the Zacks Instruments – Control industry's growth of 10.2%.

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Other Key Picks From the Computer and Technology Space

Some better-ranked stocks from the broader technology space are NETGEAR, Inc. ((NTGR - Free Report) ), Ubiquiti Inc. ((UI - Free Report) ) and Watts Water Technologies, Inc. ((WTS - Free Report) ). NTGR sports a Zacks Rank #1 (Strong Buy), while UI and WTS carry a Zacks Rank #2. You can see the complete list of today’s Zacks #1 Rank stocks here.

NETGEAR’s earnings beat the Zacks Consensus Estimate in each of the trailing four quarters, with the average surprise being 179.12%. In the last reported quarter, NTGR delivered an earnings surprise of 105.71%. Its shares have surged 89.3% in the past year.

Ubiquiti earnings beat the Zacks Consensus Estimate in each of the trailing four quarters, with the average surprise being 29.93%. In the last reported quarter, UI delivered an earnings surprise of 61.29%. UI shares have skyrocketed 170.2% over the past year.

Watts Water’s earnings beat the Zacks Consensus Estimate in each of the trailing four quarters, with the average surprise being 6.57%. In the last reported quarter, WTS delivered an earnings surprise of 11.79%. Its shares have increased 28.1% in the past year.

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