Battery Cell Deterioration Detection Using Charge-End Voltage Difference
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Solution Overview
Problem
Existing battery management systems fail to accurately detect deteriorated battery cells due to insufficient reflection of voltage changes during the calculation period, leading to increased computation and energy consumption, and difficulty in distinguishing between natural degradation and manufacturing defects.
Innovation Solution
An apparatus and method that detects deteriorated battery cells by measuring voltage differences at the end time points of charging and discharging, using a diagnosis unit to set conditions based on State of Health (SOH) and comparing voltage differences with predefined thresholds to identify deteriorated cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage data is calculated on a daily, monthly, and yearly basis to determine deterioration, then the detection reference can be established, but the computation amount increases and energy is consumed unnecessarily
Solution Approach 1:
The patent segments the continuous voltage data into specific critical time points (charging end time point and discharging end time point) rather than calculating continuously or periodically. This segmentation reduces computation by focusing only on the moments when voltage difference is most indicative of deterioration, eliminating unnecessary energy consumption while maintaining detection accuracy.
Solution Approach 2:
The patent performs preliminary identification of charging and discharging end time points based on current threshold conditions, then only calculates voltage difference at these pre-identified moments. This preliminary action avoids the need for continuous or periodic calculations, reducing energy consumption while ensuring deterioration is detected at the most informative moments.
2Measurement precision
If minimum VMin, maximum VMax, and average VAvg of voltage are calculated based on day when highest charge SOC was used and day when lowest discharge SOC was used, then the voltage change can be reflected, but it is difficult to determine whether the difference is natural degradation or defective factors
Solution Approach 1:
The patent extracts and isolates the voltage difference phenomenon at specific critical moments (charging end and discharging end time points) from the complex continuous voltage data. By taking out only the relevant voltage differences at these specific moments and comparing them against threshold values, the patent enables clear determination of deterioration without the confusion of natural degradation variations, solving the difficulty of identifying deterioration causes.
Solution Approach 2:
The patent changes the measurement parameter from continuous voltage values (VMin, VMax, VAvg) to voltage difference at specific time points (ΔV at charging end and discharging end). This parameter change simplifies the detection criterion to a clear threshold comparison, making it easier to distinguish between natural degradation and defective factors while maintaining accurate reflection of voltage changes.
3Measurement precision
If data acquired every second is calculated over the entire battery operation period, then the voltage change is sufficiently reflected, but the amount of computation is large and available energy is reduced
Solution Approach 1:
The patent extracts only the essential voltage difference information at charging end and discharging end time points from the continuous second-by-second data stream. This extraction approach reflects the critical voltage changes that indicate deterioration while eliminating the need to process all intermediate data points, dramatically improving computation efficiency without sacrificing detection accuracy.
Solution Approach 2:
Instead of performing complete continuous calculation over the entire operation period, the patent applies partial action by calculating voltage difference only at the critical end time points of charging and discharging. This partial calculation approach provides sufficient information for deterioration detection while significantly reducing computational burden and preserving available energy.
Data Source
AI summary
The present invention discloses an apparatus and method for detecting a deteriorated battery cell including a measurement unit that measures a state of a battery, an estimation unit that estimates a state of health (SOH) of the battery, a diagnosis setting unit that sets a diagnosis start condition, a diagnosis section, and a determination condition of the deteriorated battery cell according to the SOH of the battery, a diagnosis performance decision unit that determines a detection performance condition of the deteriorated battery cell after an end of charging/discharging of the battery, and a deterioration determination unit that determines the deteriorated battery cell by calculating a voltage difference in the charging and discharging end section and comparing the measurement value with a set value.