Intelligent Protection Device for Electric Vehicle Charging Interfaces — Project Overview

As the new energy vehicle market continues to expand globally, charging safety and reliability have become critical concerns for both manufacturers and operators. To address existing vulnerabilities in EV charging interfaces — including inadequate waterproofing, overvoltage exposure, overcurrent risk, and leakage hazards — Xiangyang Tenglong Automobile Co., Ltd. initiated the development of an Intelligent Protection Device for Electric Vehicle Charging Interfaces in April 2020 (Project No. RD16).

The project focused on enhancing the reliability and safety of AC charging interfaces through the integration of innovative structural engineering and intelligent control technology, resulting in a multi-function protection device purpose-built for new energy vehicle applications.

Core Technical Innovations

The device incorporates a precision locking mechanism using a limit slide rail and slot configuration, effectively preventing connector loosening under vibration and repeated use. A flexible rubber waterproof baffle installed at the top of the housing provides robust moisture sealing, structurally preventing water ingress into the socket body — a common failure point in existing charging interface designs.

On the electrical safety side, the device integrates a current sensor linked to a master control relay system that monitors charging current in real time and automatically activates circuit protection when anomalies are detected. This delivers five layers of protection: overvoltage protection, undervoltage protection, overcurrent protection, leakage protection, and internal overheating protection. A high-low level relay series connection design further enhances overall system reliability, while the device's strong adaptive response to supply-side voltage fluctuations reduces the need for manual monitoring and lowers operational costs.

Intellectual Property

The project was completed and accepted in December 2020, with all primary technical objectives successfully achieved. The development resulted in the successful commercialization of an invention patent: "A New Energy Vehicle Charging Interface Locking Device with Waterproof Structure" (Patent No. ZL201810502766.8). The patent covers the complete structural design of the charging interface housing, cover plate, and locking mechanism, providing comprehensive intellectual property protection for the project's core innovations.

Application and Commercial Value

The device has been successfully integrated into Tenglong Auto's new energy vehicle product line, with applications spanning pure electric buses, new energy commercial vehicles, and special-purpose vehicles. By delivering measurable improvements in charging safety, extending interface service life, and reducing maintenance costs, the device strengthens the overall safety credentials and market competitiveness of Tenglong Auto's new energy product range — supporting the company's broader commitment to building world-class intelligent green transportation solutions.

RD16Design of an Intelligent Protection Device for Electric Vehicle Charging Interfaces