Single-Switch Traction Battery Leakage Detection Circuit
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Solution Overview
Problem
Existing leakage detection systems for vehicle batteries struggle to accurately detect electrical isolation issues, particularly when similar leakage values are present on both sides of the battery, leading to undetectable overall leakage.
Innovation Solution
A simplified leakage detection system with a single switch and measurement circuitry that measures voltage across resistors on both sides of the battery pack, allowing for accurate prediction of leakage resistance regardless of leakage conditions, including similar leakage on both sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional leakage detection systems are used, then leakage can be detected under normal conditions, but detection accuracy deteriorates when similar leakage values are present on both sides of the battery
Solution Approach 1:
The patent applies periodic action by sequentially switching the first and second switches between on and off states. The controller measures voltage across the first resistor when the first switch is on and the second switch is off, then measures voltage across the second resistor when the second switch is on and the first switch is off. This periodic switching enables accurate detection of leakage on both sides of the battery even when leakage values are similar, resolving the contradiction between measurement precision and detection reliability.
2Adaptability or versatility
If multiple switches and measurement devices are used on both sides, then detection coverage is improved, but device complexity increases
Solution Approach 1:
The patent merges the detection functions for both sides of the battery into a single integrated circuit. The first and second switches, along with their respective resistors, are combined in a unified detection circuit controlled by a single controller. This merging approach maintains comprehensive detection coverage while reducing device complexity compared to having separate independent detection systems for each side.
Solution Approach 2:
The controller performs multiple detection functions using the same hardware components. By sequentially activating different switches and measuring voltages across different resistors, the single controller handles both positive terminal leakage detection and negative terminal leakage detection. This multi-functionality reduces overall system complexity while maintaining comprehensive detection capability.
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 system effectively detects leakage on both sides of the battery pack, ensuring reliable isolation detection and compliance with safety standards, even in conditions where leakage values are similar, using a single switch and voltage measurement device.
Implementation Method 1
measurement circuitry configured to measure a voltage at a resistor of one of the sides when the switch is open and closed
Data Source
AI summary
A leakage detection system for a battery pack of a vehicle may include detection circuitry having a first side connecting a positive terminal of the pack to ground and a second side connecting a negative terminal of the pack to ground, and including no more than one switch among the sides. The system may also include measurement circuitry configured to measure a voltage across a resistor of one of the sides when the switch is open and closed, and a controller programmed to output a leakage associated with the battery pack based on the voltage.