Coaxial EV Charging Connector Structure for Creepage Clearance
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Solution Overview
Problem
Conventional charging connectors for electric vehicles fail to meet the safety specifications for creepage distance and electrical clearance as defined by the National Standard of People's Republic of China GB 24155-2020, specifically having a creepage distance less than the required 17.6 millimeters and electrical clearance less than 2.5 millimeters.
Innovation Solution
A charging connector design featuring a connector base with a first conductive terminal and an isolation member having annular grooves, increasing the internal diameter of the lower cavity and forming annular grooves on the isolation member's surface to enhance creepage distance and electrical clearance, along with insulation layers on external connecting sheets to meet safety specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connector structure with coaxial terminals is used, then compact design is achieved, but creepage distance requirement of 17.6mm cannot be met (only 3.8mm achieved)
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional configuration by positioning the first conductive terminal above the second conductive terminal with vertical separation. The isolating holder extends vertically to create multiple levels, allowing creepage distance to be measured along the surface path from the first terminal, down the isolating holder, to the second terminal, achieving 17.6mm creepage distance while maintaining compact overall dimensions.
2Reliability
If conventional connector structure is used, then manufacturing simplicity is maintained, but electrical clearance requirement of 2.5mm is not satisfied (only 1.2mm achieved)
Solution Approach 1:
The patent introduces an isolating holder as an intermediary component between the first conductive terminal and the second conductive terminal. This isolating holder provides both mechanical support and electrical insulation, ensuring that the electrical clearance between terminals exceeds 2.5mm. The isolating holder acts as a mediator that maintains the required insulation distance while simplifying the overall assembly process compared to direct terminal mounting.
3Temperature
If larger internal diameter of lower cavity is implemented, then isolation member surface area increases for heat dissipation, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the connector into distinct functional components: a connector base, a first conductive terminal, an isolating holder, and a second conductive terminal. The isolating holder is designed as a separate component with specific geometric features including an outer annular groove and an inner annular groove. This segmentation allows the lower cavity to have a larger internal diameter for heat dissipation while the isolating holder maintains the required insulation clearance, reducing the overall manufacturing precision requirements compared to a monolithic design.
Data Source
AI summary
A charging connector for an electrical vehicle has a connector base, a tubular first conductive terminal mounted in the connector base, an insulating isolation member mounted in the first conductive terminal, and a second conductive terminal mounted in a center of the isolation member and coaxially disposed in and electrically isolated from the first conductive terminal. The isolation member has at least one annular groove recessed in an upper surface of the isolation member, extending downwardly, and coaxially surrounding the second conductive terminal. A creepage distance between the first conductive terminal and the second conductive terminal is increased and a surface area for heat dissipation is increased to meet safety specifications.