BMS EIS Quick Diagnosis for Early Thermal Runaway Detection
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Solution Overview
Problem
Conventional battery management systems (BMS) fail to detect thermal runaway in lithium-ion batteries before it occurs, leading to ineffective post-detection and potential fire spread, as they lack proactive measures.
Innovation Solution
Implementing a battery management system (BMS) with an electrochemical impedance spectroscopy (EIS) function that switches to a quick diagnosis mode using a single preset frequency to measure impedance, allowing for early detection of thermal runaway by monitoring impedance fluctuations in each cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional BMS with multiple EIS frequencies is used for comprehensive impedance measurement, then measurement precision is improved, but response time deteriorates when thermal runaway detection is needed
Solution Approach 1:
The system dynamically switches between full multi-frequency EIS measurement mode and quick single-frequency diagnosis mode based on operational conditions. During normal operation, comprehensive multi-frequency measurements maintain high precision. When thermal runaway risk is detected, the system transitions to quick diagnosis mode using a predetermined frequency, sacrificing some measurement comprehensiveness for rapid response.
Solution Approach 2:
The system changes the measurement parameters (frequency points) based on the diagnostic needs. In quick diagnosis mode, only a predetermined frequency is used for rapid assessment. In normal mode, multiple frequencies are measured for comprehensive characterization. This parameter adaptation resolves the contradiction between speed and precision.
2Measurement precision
If multiple frequencies are used for EIS measurement to ensure accurate impedance characterization, then measurement precision is improved, but measurement time increases
Solution Approach 1:
In quick diagnosis mode, the system performs partial measurement by using only a predetermined frequency instead of the full multi-frequency spectrum. This partial action is sufficient for detecting thermal runaway conditions, achieving adequate diagnostic capability with significantly reduced measurement time.
3Reliability
If comprehensive impedance measurement at multiple frequencies is performed, then reliability of thermal runaway detection is improved, but loss of time increases
Solution Approach 1:
The system pre-selects a predetermined frequency that is most sensitive to thermal runaway conditions. This preliminary preparation allows the system to immediately use this optimized frequency when thermal runaway detection is needed, achieving both reliability and speed without requiring full multi-frequency measurements at that moment.
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 proactive detection of thermal runaway, reducing the risk of fire spread by predicting thermal runaway events through cell-by-cell impedance measurements, minimizing false predictions, and enabling rapid identification of abnormal conditions.
Implementation Method 1
an EIS meter configured to measure impedance of the connected cells using EIS for measuring impedance using multiple frequencies
Data Source
AI summary
An embodiment relates to an apparatus and method for proactive detection of thermal runaway using a battery management system (BMS) having an electrochemical impedance spectroscopy (EIS) function, and more specifically, to an apparatus and method for proactive detection of thermal runaway using a BMS having an EIS function which sets a quick diagnosis mode to measure impedance using only one preset frequency among multiple impedance measurement frequencies of the EIS of a module BMS when a thermal runaway prediction event occurs, and in a quick diagnosis mode, simultaneously measures the impedance of each cell in a battery module by the set frequency through the EIS, and predicts and alerts the possibility of thermal runaway according to the fluctuation deviation of the measured impedance.