Redundant Battery Isolation Circuit for Leakage Current Shutdown
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Solution Overview
Problem
Existing overcurrent protection systems in electrified vehicles have slow response times and limited accuracy in detecting overcurrent events, posing safety risks due to potential electrical hazards such as electric shocks and fires.
Innovation Solution
An electrical isolation system with a redundant overcurrent protection circuit, including an overcurrent protection switch and a redundant overcurrent protection circuit, which operates independently of the primary system to enhance responsiveness and safety by breaking the high voltage battery circuit in fault modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single overcurrent protection switch is used, then the device complexity is reduced, but the reliability and responsiveness to leakage current are insufficient
Solution Approach 1:
The patent divides the single protection function into two independent protection paths: a primary protection path with an overcurrent protection switch and a secondary protection path with a redundant overcurrent protection circuit. Each path operates independently to detect and respond to leakage current, ensuring that if one path fails, the other can still provide protection. This segmentation increases reliability without requiring a single complex system.
Solution Approach 2:
The redundant overcurrent protection circuit is pre-configured with reed elements and electromechanical switches that are ready to activate immediately upon detecting leakage current. The circuit includes pre-positioned components such as reed switches connected to battery terminals and chassis ground, which can rapidly respond to fault conditions without requiring complex real-time processing or control algorithms.
2Speed
If the overcurrent protection switch is controlled by a control system, then the ease of operation is improved, but the response time to leakage current is delayed
Solution Approach 1:
The redundant overcurrent protection circuit operates autonomously without requiring control system intervention. The reed elements directly detect leakage current and automatically trigger the electromechanical switch to open the circuit. This self-service mechanism eliminates delays associated with control system processing, signal transmission, and software execution, achieving rapid response while maintaining operational simplicity through passive, automatic protection.
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
The redundant system provides enhanced safety by ensuring rapid and reliable disconnection of the high voltage battery circuit in case of leakage current, reducing the risk of electrical hazards even when primary protection fails.
Implementation Method 1
the redundant overcurrent protection circuit includes at least one reed element, wherein the at least one reed element includes a reed relay
Data Source
AI summary
An electrical isolation system for a high voltage battery circuit in an electrified vehicle, the electrical isolation system mounted to a chassis of the electrified vehicle and comprising: an overcurrent protection switch that is configured to be responsive to leakage current present in the high voltage battery circuit by breaking the high voltage battery circuit and a redundant overcurrent protection circuit that is configured to be responsive to leakage current present in the high voltage battery circuit in a manner that is different from the overcurrent protection switch to break the high voltage battery circuit such that the redundant overcurrent protection circuit is more responsive in one or more fault modes of the electrified vehicle than is the overcurrent protection switch alone, wherein the system is included in a control unit of the electric vehicle