High-current DC relays for EV and energy storage

The expansion of electric mobility and stationary energy storage is increasing demand for compact switching components capable of handling high DC voltages and currents. In this context, OMRON Electronic Components Europe introduced the G9KD series PCB-mount DC relays for safety isolation in energy storage systems (ESS) and electric vehicle (EV) fast-charging infrastructure.

Relay-based isolation in high-voltage DC architectures
The OMRON G9KD series is specified for applications requiring switching and isolation at up to 1500 V DC. The relays support a 100 A make current and a 150 A carry and break current, targeting ESS power-conditioning circuits and EV charger control units.

Typical use cases include configuration switching in EV charging systems, where power levels are dynamically adjusted between vehicles and charging equipment. These switching functions support flexible charging infrastructure design and can contribute to improved utilisation of charging assets within EV charging infrastructure.

By supporting operation at DC bus voltages of 1000 V and above, the relays are aligned with trends toward higher-voltage battery systems and grid-connected storage architectures intended to increase system efficiency and power density.

From contactors to PCB integration
The G9KD relays are designed to replace conventional contactors in certain applications, enabling greater PCB-level integration. This transition supports automated assembly processes and may reduce the need for manual wiring typically associated with larger electromechanical switching devices.

The compact relay format, measuring 60.5 mm × 43.5 mm × 56.5 mm, supports equipment miniaturisation. The devices use a single-pole single-throw normally open configuration (SPST, type 1a).

A main contact gap of 6 mm provides electrical isolation distance, while initial contact resistance below 4 mΩ limits conduction losses and heat generation. These characteristics are relevant for maintaining efficiency and thermal stability in high-current power electronics systems.

Diagnostic features and compliance considerations
Optional auxiliary contacts rated at 1.0 A are available for contact status monitoring and diagnostic feedback. These normally closed auxiliary contacts (type 1b) can support failure detection strategies in safety-critical systems.

The auxiliary contacts conform to IEC/EN 60947-4-1, a standard applicable to electromechanical switching devices used in industrial control applications.

Through the introduction of the G9KD series, OMRON Electronic Components Europe addresses switching requirements in high-voltage DC systems used in electrification and stationary energy storage, where compact integration and reliable isolation remain key design considerations.

Edited by industrial journalist Aishwarya Mambet, with AI-assistance.

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