High Voltage Service Disconnect Assembly Isolation Resistance Fault Detection
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Solution Overview
Problem
Current methods fail to provide a straightforward way for vehicle service personnel to determine the presence of an isolation resistance fault in electric vehicles, posing a safety risk due to the inability to easily identify high voltage issues.
Innovation Solution
A high voltage service disconnect assembly that includes a detection circuit and a light emitting device to visually indicate isolation resistance faults between battery pack terminals and the vehicle enclosure, utilizing comparator circuits and conductive pins to detect and signal faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high voltage service disconnect assemblies are used, then the device structure is simple, but the ability to detect and indicate isolation resistance faults is lacking
Solution Approach 1:
The detection circuit performs isolation resistance fault detection before servicing begins, and the light emitting device provides advance visual warning of faults. This preliminary detection action allows service personnel to identify hazards before approaching the battery pack, resolving the contradiction by adding detection functionality without requiring complex post-detection systems.
Solution Approach 2:
The light emitting device acts as an intermediary between the detection circuit and service personnel, converting electrical fault signals into visible light indicators. This intermediary translates complex electrical measurements into simple visual warnings, improving reliability of fault indication while keeping the overall system relatively simple through functional decomposition.
2Difficulty of detecting and measuring
If isolation resistance fault detection is added to the service disconnect assembly, then fault identification capability is improved, but the device complexity increases
Solution Approach 1:
The service disconnect assembly is segmented into distinct functional modules: the existing service disconnect functionality and the added detection circuit with light emitting device. This segmentation allows the detection system to be added as a separate, relatively simple module rather than redesigning the entire assembly, thus improving detection capability while limiting the increase in overall complexity.
Solution Approach 2:
The detection system replaces complex manual isolation resistance measurement procedures with an automated electrical detection circuit that provides direct electrical measurement and automatic visual indication. This substitution of manual mechanical/electrical procedures with an automated circuit simplifies the detection process despite adding circuitry, as it eliminates the need for separate measurement equipment and procedures.
3Object-affected harmful factors
If a visual indication system is implemented, then service personnel safety is improved, but energy consumption increases
Solution Approach 1:
The light emitting device operates periodically or on-demand based on detection results rather than continuously, activating only when isolation resistance faults are detected or when the service disconnect is engaged. This periodic operation provides necessary safety visual indications while minimizing energy consumption compared to continuous operation, resolving the contradiction between safety improvement and energy use.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick and effective determination of isolation resistance faults, providing a visual indication to ensure safe servicing of electric vehicles by identifying faults between battery pack terminals and the vehicle enclosure.
Implementation Method 1
a light emitting device to visually indicate isolation resistance faults between battery pack terminals and the vehicle enclosure
Data Source
Figure 1~2
Figure 3~4
AI summary
A high voltage service disconnect assembly is provided. The battery pack has an enclosure, first and second battery modules, and positive and negative pack voltage terminals. The assembly includes a housing securing first and second conductive pins thereon. The first conductive pin is coupled to a negative voltage terminal of the first battery module. The second conductive pin is coupled to a positive voltage terminal of the second battery module. The assembly further includes a detection circuit electrically coupled to the first and second conductive pins. The detection circuit outputs a first isolation resistance fault signal when a first isolation resistance fault is detected between the negative pack voltage terminal and the enclosure.