EV DC Inlet Cover Locking for Contactor Welding Safety
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Solution Overview
Problem
Existing electric vehicle charging systems face challenges in ensuring safety and convenience when anomalies occur on the extension signal line, such as welding of contactors, which can lead to exposure of live lines and hinder charging processes.
Innovation Solution
The electric vehicle is equipped with a vehicle-side charging connector that integrates both AC and DC inlets, a contactor welding detection unit, a DC inlet cover, a DC lock mechanism, and a lock controller. The DC inlet cover is designed to remain closed and locked when contactor welding is detected, while allowing AC charging to proceed safely through the AC inlet, which is only covered by the charging lid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DC inlet cover is locked when contactor welding is detected, then safety is improved by preventing exposure of live lines, but charging convenience deteriorates as DC charging cannot proceed
Solution Approach 1:
The charging inlet is divided into separate AC and DC components with independent covers and lock mechanisms. The DC inlet cover can be independently locked when contactor welding is detected, while the AC inlet remains accessible through its own cover, allowing segmented safety control based on the type of charging anomaly detected
Solution Approach 2:
The control unit acts as an intermediary that detects contactor welding conditions and selectively activates the DC inlet cover lock mechanism. This intermediary control enables automatic safety responses that prevent direct user exposure to hazardous conditions while maintaining system functionality where safe
2Reliability
If a separate DC inlet cover and lock mechanism are added, then safety is improved by isolating the DC inlet, but device complexity increases
Solution Approach 1:
The vehicle-side charging connector integrates both AC and DC inlets within a single connector structure, and the control unit manages multiple functions including anomaly detection, selective cover locking, and charging control. This multi-functionality reduces the need for entirely separate systems while maintaining safety
Solution Approach 2:
The DC inlet cover is nested within the overall charging lid structure, and the lock mechanism is integrated into the existing connector assembly. This nested arrangement allows the DC inlet to be isolated when needed while maintaining a compact overall structure that doesn't significantly increase device complexity
3Adaptability or versatility
If the vehicle-side charging connector integrates both AC and DC inlets, then adaptability is improved by using one connector for both charging types, but safety risk increases due to potential exposure of live lines
Solution Approach 1:
The integrated connector is segmented into distinct AC and DC inlet regions, each with its own protective cover. The DC inlet cover can be independently locked to prevent access to live DC lines when anomalies are detected, while maintaining the integrated connector structure for adaptability
Solution Approach 2:
The DC inlet cover and lock mechanism provide preliminary protection against harmful exposure of live DC lines. When contactor welding is detected, the lock mechanism preemptively secures the DC inlet cover to prevent user contact with hazardous energized components before damage can occur
Data Source
AI summary
An electric vehicle includes a battery, a charging lid, a vehicle-side charging connector, a contactor, a contactor welding detector, a DC inlet cover, a DC lock mechanism, and a lock controller. The battery is to be charged with power supplied from an external power supply. The vehicle-side charging connector is disposed inside a position of the charging lid in the electric vehicle and includes an AC inlet for AC charging and a DC inlet for DC charging. The contactor is provided on a power line connecting the DC inlet to the battery. The contactor welding detector is configured to detect welding of the contactor. The DC inlet cover covers the DC inlet without covering the AC inlet in a state where the DC inlet cover is in a closed state. The DC lock mechanism locks the DC inlet cover in the closed state.