Battery Cell Degradation Diagnosis from Cycle Voltage Deviation
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Solution Overview
Problem
Existing battery degradation diagnosis methods are time-consuming and inefficient, particularly in estimating the State Of Health (SOH) of batteries, which can lead to unexpected accidents due to inaccurate capacity decreases.
Innovation Solution
An apparatus and method that measures voltage deviations in battery cells across multiple cycles, calculates voltage deviation change rates, and diagnoses relative degradation based on these rates, allowing for quick and accurate assessment of battery cell health without relying on cycle retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the SOH of the battery is estimated by measuring the amount of voltage increase when the battery is charged and calculating remaining life using statistical techniques, then the diagnosis can be performed with simple measurement equipment, but it takes a considerable amount of time to diagnose the remaining life or the degree of degradation
Solution Approach 1:
The patent changes the diagnostic parameter from voltage increase amount to voltage deviation from reference voltage. By measuring voltage deviation during charging/discharging cycles and comparing it to reference values, the system achieves rapid degradation assessment without requiring complex statistical calculations, thus reducing diagnosis time while maintaining accuracy
Solution Approach 2:
The patent replaces the statistical calculation method (particle filter) with a direct voltage deviation comparison method. This substitution eliminates the time-consuming computational process while providing accurate degradation diagnosis through straightforward voltage measurements against reference thresholds
2Measurement precision
If the voltage deviation change rate is calculated by selecting multiple cycle sections satisfying predetermined conditions, then the degradation diagnosis becomes more accurate, but the calculation complexity increases
Solution Approach 1:
The patent segments the charging/discharging cycles into multiple cycle sections, each satisfying predetermined conditions. By dividing the overall cycle into manageable sections and calculating voltage deviation change rates for each segment, the system achieves comprehensive degradation assessment while keeping individual calculations simple and systematic
Data Source
AI summary
An apparatus for diagnosing a degree of degradation of a battery includes a measuring unit configured to measure a voltage of each of a plurality of battery cells in each of a plurality of cycles where charging and discharging is performed and output voltage information about the plurality of measured voltages, and a control unit configured to receive the plurality of voltage information, calculate a voltage deviation of each cycle for each battery cell based on a reference voltage of each of the plurality of battery cells, select a cycle section satisfying a predetermined condition for each of the plurality of battery cells based on the calculated voltage deviation, calculate a voltage deviation change rate corresponding to each of the plurality of selected cycle sections, and diagnose a relative degree of degradation of the plurality of battery cells based on the plurality of calculated voltage deviation change rates.