Battery Micro Short Circuit Detection via Voltage Difference Rate
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Solution Overview
Problem
Existing methods struggle to accurately detect micro short circuits in battery packs due to interference from state of charge (SOC) and state of health (SOH) variations, leading to false detections.
Innovation Solution
A battery abnormality detection system that calculates the increasing rate of voltage difference between cells or cell blocks within a specific SOC range, using data processing to determine the occurrence of a micro short circuit by analyzing time-series voltage data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the voltage difference between cell blocks is used to detect micro short circuits, then detection capability is improved, but false detection increases when SOC or SOH differences exist between cell blocks
Solution Approach 1:
The patent changes the parameter used for detection from absolute voltage difference to rate of change of voltage difference. By detecting how quickly the voltage difference changes over time rather than just the static difference, the system can distinguish between normal voltage variations due to SOC/SOH differences and abnormal voltage changes caused by micro short circuits. This parameter transformation resolves the contradiction by making detection insensitive to steady-state voltage differences while remaining sensitive to abnormal changes.
2Measurement precision
If the SOC-OCV curve method is used to normalize cell voltage, then the effect of SOC range on voltage is reduced, but the method becomes unusable when the SOC-OCV curve is unclear or changes greatly due to deterioration
Solution Approach 1:
The patent extracts only the necessary information (voltage difference and its rate of change) from the complex SOC-OCV curve methodology. Instead of requiring the full SOC-OCV curve and its normalization process, the invention directly monitors the time-series voltage difference between cell blocks. This extraction approach maintains detection accuracy while eliminating the requirement for clear SOC-OCV curves, thereby improving adaptability to deteriorated cells.
Data Source
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Figure 2A~2B
Figure 3A~3C
AI summary
A data processing unit is configured to calculate, on a time-series basis, the voltage difference between a reference voltage and the minimum voltage of a plurality of cells or cell blocks included in a battery pack and connected in series. A determination unit is configured to, when an increasing rate of the voltage difference is equal to or greater than a threshold, determine that a micro short circuit has occurred in the cells or cell blocks having the minimum voltage. The data processing unit calculates the increasing rate of the voltage difference by using voltage data in a period in which the State-Of-Charge (SOC) of the battery pack is within a predetermined SOC range.