Battery Cell Voltage Slope Analysis for Abnormality Diagnosis
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Solution Overview
Problem
Existing methods for diagnosing voltage abnormalities in battery cells are inefficient and inaccurate, particularly when voltage differences at different time points are not significant or when lithium plating occurs, as they do not account for temperature and current variations.
Innovation Solution
A battery diagnosis apparatus and method that utilizes a voltage sensing circuit, storage medium, and control circuit to analyze cell voltage slopes over time, setting boundary conditions for normal slope ranges and diagnosing abnormalities based on deviations from these ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage difference comparison method is used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent transforms the voltage abnormality detection from comparing absolute voltage differences to analyzing voltage change rates (slopes) over time. By calculating the rate of voltage change (dV/dt) and comparing it against threshold values, the system achieves higher detection precision while maintaining simple computational requirements suitable for low-performance processors.
2Ease of operation
If simple voltage difference comparison is used, then ease of operation is improved, but reliability deteriorates
Solution Approach 1:
The method shifts from static voltage difference comparison to dynamic voltage slope analysis. By computing the time derivative of voltage and comparing against predetermined thresholds, the system reliably detects abnormalities such as lithium plating while keeping the operational logic simple and easy to implement.
Solution Approach 2:
The system continuously monitors voltage over time and uses the rate of change as feedback to determine abnormality. This dynamic feedback mechanism improves reliability by capturing transient conditions that static comparisons would miss, while maintaining operational simplicity through threshold-based decision logic.
3Measurement precision
If voltage slope analysis is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent achieves high measurement precision by analyzing voltage change rates rather than absolute differences. The calculation complexity is managed by using simple linear slope computations (ΔV/Δt) and threshold comparisons, which can be efficiently executed even on processors with limited computational power.
Data Source
AI summary
A battery diagnosis apparatus, which includes a voltage sensing circuit to generate a voltage signal indicating a cell voltage of a battery cell; a storage medium to store time; and a control circuit configured to receive the voltage signal and record the time series data for the cell voltage in the storage medium, determine a first cell voltage slope and a second cell voltage slope in a first time section and a second time section based on the time series data, determine an average slope of the cell voltage in a third time section between the first time section and the second time section based on the time series data, set the first cell voltage slope and the second cell voltage slope as boundary conditions of a normal slope range, and diagnose a voltage abnormality when the average slope of the cell voltage is outside the normal slope range.