High-power PCB relay delivers faster and more compact EV charger wallboxes

Omron Electronic Components Europe has launched a new high-power PCB relay for use in AC wallboxes for Mode 3 AC EV charging stations. The G9KC relay provides the lowest contact resistance available on the market and produces notably less load terminal heat rise when operating compared to equivalent devices. This opens new opportunities for designers and manufacturers of EV chargers to create systems that can charge faster and more efficiently, with a higher reliability and expected lifetime.

As EVs grow in popularity, demand for dependable EVSE or EV chargers is also rapidly increasing. Improved charging speeds can be accomplished by using higher charging currents; however, this needs higher-rated electronic components, generating more heat inside the wallbox enclosure.

Higher temperatures within the wallbox can greatly affect charging performance and efficiency and can cause temporary limitations on charging power. Furthermore, increased heat cycles and heat levels can cause components to wear prematurely and fail. Balancing the increasing amounts of heat dissipated by higher power components, with the desire to reduce the overall system footprint, is, therefore, a major challenge for designers of EV charging infrastructure.

This relay uses an optimised structure including a mechanically coupled, double break contact design for demanding AC wallbox and Pedestal Charger designs for home, workplace, commercial and industrial settings. Designed and developed to high Japanese standards, its aim is to improve energy efficiency while reducing heat dissipation. As a result, it contributes effectively towards the overall reduction in operating temperature in a typical 22kW (max 32A/Phase) wallbox. This enables faster, more efficient charging and unlocks new possibilities for wallbox designers to develop more compact and robust designs.

The relay's four-pole structure means that a single device can replace larger multi-pole Contactors and combinations of one and two pole, reducing the footprint required. With a guaranteed initial contact resistance of less than 6mOhm, it has the potential to contribute less as a hotspot while improving charging efficiency and performance. The device's lower operating temperature decreases the likelihood of the number of charge cycles reaching charging current throttling thresholds while also contributing to improved reliability and longevity of the relays and surrounding components.

Unlike contactors, the device can be mounted on a PCB, which can help to facilitate smaller and lighter designs in various products, including EVSE/chargers, UPS, grid-interactive and commercial and industrial inverters and converters. The device has been approved by safety standard certification authorities of UL/C-UL, TUV and CQC. It has been designed to fulfil the requirements of IEC 62955 - Residual direct current detecting device (short circuit capability), and IEC 61851-1 - Electric vehicle conductive charging systems, alongside a wide range of other relay safety applicable standards.