Battery Cell OCV Diagnosis with SOH-Based Noise Filtering
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Solution Overview
Problem
Conventional battery management systems fail to accurately diagnose inner short-circuits in battery cells due to the lack of consideration for the difference in degradation degree between cells, leading to potential under-voltage defects and increased ignition risk.
Innovation Solution
A battery management apparatus that calculates the state of health (SOH) and open circuit voltage (OCV) of each battery, identifies noise batteries based on threshold ranges, and diagnoses abnormal batteries by analyzing deviations in OCVs between target batteries, using statistical methods to set and apply weights to standard deviations for accurate diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional battery management apparatus diagnoses inner short-circuit by determining relative voltage deviation according to coupling order without considering degradation degree, then the diagnosis method is simple, but the measurement precision of voltage fluctuation due to inner short-circuit deteriorates
Solution Approach 1:
The patent changes the diagnosis parameters from simple relative voltage deviation to a comprehensive evaluation that includes voltage deviation, degradation degree (SOH), and service life. By introducing these additional parameters and their weighted combinations, the system achieves more precise detection of inner short-circuits while maintaining manageable complexity through structured calculation procedures.
Solution Approach 2:
The patent segments the battery cells into different categories based on their degradation degrees and service lives. By dividing the batteries into groups (e.g., noise batteries, target batteries) and applying different diagnosis criteria to each group, the system simplifies the overall diagnosis process while improving precision for each segment.
2Device complexity
If battery management apparatus does not consider difference in degradation degree between battery cells, then the device complexity is low, but the reliability of inner short-circuit diagnosis deteriorates
Solution Approach 1:
The patent introduces degradation degree (SOH) and service life as new diagnosis parameters. By changing the parameter set to include these factors, the system significantly improves the reliability of inner short-circuit diagnosis. The weighted combination of voltage deviation, SOH, and service life creates a more robust diagnosis criterion that reduces false positives and false negatives.
Solution Approach 2:
The patent implements a feedback mechanism where the diagnosis results are used to update the SOH and service life values of battery cells. This continuous feedback loop allows the system to adapt to changing battery conditions and maintain high diagnostic reliability over the battery's lifecycle.
3Ease of operation
If battery management apparatus uses fixed threshold ranges for SOH and OCV, then the ease of operation is high, but the adaptability to different battery degradation levels deteriorates
Solution Approach 1:
The patent transforms fixed threshold ranges into dynamic, adaptive thresholds that automatically adjust based on the battery's current SOH and service life. The system calculates variable thresholds using formulas that incorporate these parameters, allowing the diagnosis criteria to adapt to different degradation levels while maintaining ease of operation through automated adjustment.
Solution Approach 2:
The patent changes the threshold parameters from static values to dynamic calculations based on SOH and service life. By making the thresholds parameter-dependent, the system achieves high adaptability to different battery states without requiring manual reconfiguration, thus maintaining ease of operation while significantly improving versatility.
Data Source
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AI summary
A battery management apparatus according to one embodiment disclosed in the present document may comprise: a data management unit for calculating the state of health (SOH) or open circuit voltage (OCV) of each of a plurality of batteries; and a controller which determines at least one noise battery on the basis of the SOH or OCV of each of the plurality of batteries, determines at least one abnormal battery on the basis of the SOH or OCV of each of the at least one noise battery and the service life of each of the at least one noise battery, and diagnoses at least one target battery on the basis of a deviation in the OCV between a plurality of target batteries excluding the at least one noise battery from the plurality of batteries.