The Critical Role of High-Voltage Direct Current Relays in Fast Charging Modules

DC charging station operators and new energy vehicle manufacturers currently face significant challenges, necessitating a reliable relay. The reliability of relays directly determines product safety reputation and operational maintenance costs. Industry data indicates that over 60% of fast-charging failures stem from high-voltage switching component failures, with contact sticking, arcing erosion, and overheating damage accounting for 82% of these incidents. This article explores the core value of high-voltage DC relays through two dimensions: application scenarios and failure solutions.

•  Core Responsibilities of Relays in Different Systems

1.  DC Charging Stations: Performance Breakthroughs in Modular and Liquid-Cooled Environments

   As fast-charging technology advances from 120kW to 720kW, charging stations have fully embraced modular design. This places stricter demands on relays:

   Our relays are specifically engineered for modular liquid-cooled charging stations. Featuring vacuum-sealed encapsulation to isolate moisture and silver-palladium alloy contacts, they deliver 1 million fault-free switching cycles at 2400A peak current. This makes them perfectly suited for demanding environments like heavy-duty truck charging stations and ultra-fast charging hubs.

2.  New Energy Vehicles: The “Safety Guardian” for Three Critical Circuits

   Within the high-voltage distribution systems of new energy vehicles, relays serve as “circuit sentinels.” Each circuit has distinct responsibilities, demanding precisely matched performance parameters.

   We offer customized solutions for the three major circuits: Main circuit relays utilize nanocrystalline cores to reduce coil losses; pre-charge circuit relays optimize pickup time to 15ms; and fast-charge circuit relays enhance arc-extinguishing systems to meet wide temperature range requirements from -40°C to 70°C.

• Targeted Solutions for Three Major Core Failures

Failures in high-voltage DC relays often stem from coordination issues among the contact, arc-quenching, and heat dissipation systems.

1. Contact Welding: A “Fatal Hazard” Under High-Frequency Switching

   During high-frequency switching, repeated arcing at contacts generates localized high temperatures, causing metal to melt and weld together. This risk is exacerbated in capacitive load scenarios where inrush currents can reach 5-10 times the rated value. We will upgrade contact materials to prevent melting adhesion. Simultaneously, plasma cleaning removes contaminants to reduce contact resistance and heat generation. An integrated pre-charge detection module ensures main contacts close only after pre-charge completion.

2.  Arc Erosion: “Energy Runaway” in High-Voltage Environments

   When high-voltage DC circuits open, sustained arcing between contacts generates high temperatures that cause contact erosion and insulation degradation, potentially leading to fire hazards. We employ vacuum arc-quenching technology: sealing contacts within a vacuum chamber extinguishes arcs within microseconds, achieving 50% higher quenching efficiency than traditional gas-filled designs. Magnetic blowback arc-quenching structures effectively reduce contact temperatures.

3. Thermal Damage: Performance Degradation Under Continuous Load

   When high currents flow for extended periods, accumulated Joule heating from contact resistance can cause coil aging and contact softening if heat dissipation is inadequate, shortening service life. Our low-resistance design employs a multi-plate parallel contact structure, reducing contact resistance below 5mΩ to minimize heat generation.

In today's landscape of continuously advancing fast-charging technology and expanding high-voltage system applications, selecting a high-voltage DC relay that understands the application, withstands pressure, and offers customization means choosing reliable safety assurance.