As a core component of the electrical control system, relays play an irreplaceable role in the field of new energy. With the rapid development of photovoltaic power generation, wind power generation, new energy vehicles and other industries, relay technology has ushered in new opportunities and challenges. This report will comprehensively analyse the application status quo, technological breakthroughs, market pattern and future development direction of relays in various fields of new energy.
In the field of photovoltaic power generation, relays bear the dual responsibilities of circuit control and system protection, and their applications run through key links such as photovoltaic arrays, inverters and energy storage systems.
For PV array control, relays mainly realise energy transmission and circuit switching functions. The output voltage and current generated by the photovoltaic panels are relatively small, requiring relay relay amplification. Modern PV relays require extremely low contact resistance (≤10mΩ) and fast response capability (action time ≤20ms) to ensure efficient system operation.
Inverter protection is a key application of relays in PV systems. The inverter is responsible for converting the DC power generated by the PV panels into AC power, while the relay controls the connection between the DC side and the inverter. The DC output of the PV plant is connected to the inverter through the relay, and when the system detects a grid abnormality or equipment failure, the relay will quickly cut off the circuit to prevent the accident from expanding. Especially in PV installations with energy storage systems, the relay also needs to manage the battery charging and discharging process to ensure seamless switching to the emergency power supply mode in the event of a grid outage.
The electrical architecture of new energy vehicles is fundamentally different from that of traditional fuel vehicles, with the main circuit operating voltage generally exceeding 200V, much higher than the 12-48V system of traditional vehicles. This high voltage characteristic makes relays play a more critical role in new energy vehicles.
High-voltage safety protection is the core function of relays in new energy vehicles. In the event of a vehicle collision or when the system detects a malfunction, the high-voltage DC relay is able to cut off the connection between the power battery and the entire vehicle circuit in milliseconds, preventing the risk of electric shock and fire. DC circuits, which do not have the over-zero characteristics of AC, produce arcs that are more difficult to extinguish, which places extremely high demands on the arc extinguishing capability of the relay.
In the battery management system (BMS), relays are involved in controlling the charging and discharging process of the power battery to prevent damage to the battery caused by overcharging and over-discharging. Especially in the braking energy recovery scenario, the relay needs to adjust the energy recovery intensity in real time according to the vehicle driving status and battery status, which puts forward higher requirements on the response speed and control accuracy of the relay.
The charging system is also inseparable from the support of high-performance relays. With the popularity of 800V high-voltage fast charging technology, the charging power has been greatly increased, which puts forward more stringent requirements on the voltage rating, current-carrying capacity and arc extinguishing capacity of relays.
Facing the harsh requirements of high voltage, high current and frequent switching unique to new energy applications, relay manufacturers have achieved significant breakthroughs in material science, structural design and manufacturing process.
Ceramic sealing technology is currently the most mainstream solution for high-voltage DC relays. Traditional epoxy resin sealing method is prone to aging under high temperature and high pressure environment, while ceramic material has excellent insulation, heat resistance and mechanical strength.
In terms of contact materials, the industry has evolved from traditional silver alloys to composite contact technology. For new energy applications in the high current breaking needs, manufacturers have developed the addition of special elements (such as SnO₂, CuO and other metal oxides) of silver-based composite materials, these materials have good resistance to arc erosion and low contact resistance characteristics.
Significant advances have also been made in the design of magnetic circuit systems. In DC circuits, the electrodynamic repulsion generated by high currents can lead to early separation of the contacts, affecting relay performance
Solid-state relay (SSR) technology is a development that has attracted much attention in recent years. Compared with traditional electromechanical relays, SSRs have no mechanical contacts and rely on semiconductor devices to switch the circuit on and off, which has the advantages of fast switching speed, no contact wear, long life and vibration resistance. Solid state relays perform particularly well in applications that require high-frequency switching, such as battery management systems.
Voltage level continues to rise: with the development of new energy technology in the direction of high voltage, such as the popularity of 800V and above high-voltage systems, the technical threshold and market value of relays will be further raised.
Intelligent development: modern high-voltage relays are beginning to integrate current and temperature sensors and communication interfaces, which can monitor their own status in real time and feedback to the control system to achieve predictive maintenance and fault warning. Although the unit price of such intelligent relays is higher, they can significantly improve system reliability and safety.
Material and process innovation: Manufacturers are exploring new contact materials, more efficient arc extinguishing technology and more compact structural designs. For example, the use of wide-bandwidth semiconductor materials such as silicon carbide (SiC) can significantly improve the switching speed and voltage withstand capability of relays.
Expanded application fields: In addition to the traditional photovoltaic and new energy vehicle fields, the demand for high-voltage relays in emerging fields such as energy storage systems and smart grids is also growing rapidly. Especially in grid-side energy storage and user-side energy storage systems, high-voltage relays play a key role in circuit protection and control.
As a key component in new energy systems, the technological progress and industrial development of relays are closely linked to the new energy revolution. From the initial simple circuit switch, to today's integrated sensing, communication and intelligent control functions of the ‘intelligent relay’, this traditional electronic component is undergoing a profound change.
In the next 5-10 years, with the deepening of the transformation of the global energy structure, relay technology will continue to develop in the direction of high voltage, intelligence and high reliability. Although solid state relay technology continues to progress, but based on economic and reliability considerations, electromechanical high-voltage DC relays in the short and medium term will remain the mainstream of the market.
For industry participants, continued increase in R&D investment, breakthroughs in key technology bottlenecks, optimisation of production processes will be the key to maintaining competitive advantage. In particular, we should pay attention to the technical challenges brought about by 800V and above high-voltage systems, as well as the product innovation opportunities under the trend of intelligence and network connectivity. Only by keeping up with the pulse of new energy industry development can we achieve new breakthroughs in the traditional field of relays and make greater contributions to the global energy transition.
