Battery Insulation Checking via Voltage Change Thresholds
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Solution Overview
Problem
Current insulation state checking methods for high-voltage batteries in electric vehicles are time-consuming, often requiring up to 30 seconds, which is undesirable for user convenience and safety, as they delay vehicle usage and may impair accuracy.
Innovation Solution
A method involving measuring voltage between a battery connection element and ground over a predefined time, evaluating for voltage changes at a temporal threshold value, and outputting a safety signal to quickly identify insulation faults, allowing for faster checks without compromising safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional insulation resistance measurement is performed to ensure safety, then the insulation state can be reliably determined, but the checking time increases to up to 30 seconds or more
Solution Approach 1:
The patent applies preliminary action by performing a quick initial voltage measurement within a short time window (e.g., 0.1 to 2 seconds) before the complete insulation resistance measurement. This preliminary check provides immediate safety information and allows early detection of obvious insulation faults, reducing the perceived waiting time for users while maintaining reliable safety determination.
Solution Approach 2:
The patent segments the insulation checking process into multiple stages: a first quick voltage measurement stage within a short time window, and potentially a second more comprehensive measurement stage. This segmentation allows the system to provide rapid initial feedback while maintaining the option for more thorough verification if needed, thus resolving the contradiction between speed and reliability.
2Productivity
If the checking time is shortened to improve user convenience, then vehicle startup is faster, but the accuracy and measurable range of the calculated resistance deteriorates
Solution Approach 1:
The patent applies partial action by performing a voltage measurement within a shortened time window that is sufficient for the intended purpose (quick safety check and vehicle startup) but not necessarily for complete characterization of all insulation conditions. This partial measurement provides adequate precision for safety determination and rapid vehicle startup without requiring the full time needed for maximum measurement accuracy.
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
This approach significantly reduces waiting times for users while ensuring safety by determining insulation faults within 0.3 to 2 seconds, allowing for immediate vehicle usage without risking short circuits, and can differentiate between normal and faulty states based on voltage saturation times.
Implementation Method 1
measuring a voltage between a connection element of the battery and a ground over a predefined time; evaluating the measured voltage and determining whether a change in the measured voltage is present at a time point that corresponds to a predefined temporal threshold value
Data Source
AI summary
A method for checking an insulation state of a battery or battery system comprising at least two batteries, comprising the following steps: measuring a voltage between a connection element of the battery and a ground over a predefined time; evaluating the measured voltage and determining whether a change in the measured voltage is present at time point that corresponds to a predefined temporal threshold value; and outputting a safety signal characterizing the insulation state on the basis of the established result.