Battery Cell SOC Evaluation Using Temperature-Rate Voltage Mapping
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Solution Overview
Problem
Existing battery state of charge (SOC) estimation methods lack accuracy and do not evaluate each battery cell individually, leading to inaccurate overall evaluation results.
Innovation Solution
A method that involves acquiring charging-discharging data of a first battery cell pack at different temperatures and rates, establishing an association table of SOCs with temperatures, rates, and voltages, and using this table to accurately estimate the SOC of each battery cell in a battery pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing algorithms (data-driven method, Kalman filtering method) are used to perform overall evaluation on a battery system, then the evaluation process is simple, but the accuracy of SOC evaluation deteriorates because individual battery cell variations are not captured
Solution Approach 1:
The patent divides the battery system into individual battery cell units for separate SOC evaluation. Instead of treating the battery system as a single aggregate unit, the method establishes separate association tables for each battery cell type, capturing individual cell characteristics and variations. This segmentation enables accurate tracking of each cell's SOC state while maintaining manageable complexity through standardized evaluation procedures for each cell type.
2Measurement precision
If individual battery cell evaluation is implemented, then SOC evaluation accuracy improves, but the complexity of data collection and processing increases
Solution Approach 1:
The patent changes the evaluation parameters from aggregate battery system level to individual battery cell level. By establishing association tables that correlate SOC with temperature, rate, and voltage parameters for each individual battery cell, the method captures cell-specific characteristics. This parameter change enables accurate SOC evaluation while the standardized table-based approach keeps processing complexity manageable.
3Measurement precision
If battery SOC is estimated using only voltage measurements, then the measurement process is simple, but the accuracy deteriorates because voltage alone cannot account for temperature and rate variations
Solution Approach 1:
The patent creates a universal association table framework that integrates multiple measurement parameters (voltage, temperature, rate) into a single comprehensive SOC evaluation system. The association tables store SOC values corresponding to different combinations of voltage, temperature, and rate parameters, allowing the system to account for all these factors simultaneously. This multi-functional approach maintains measurement simplicity while significantly improving accuracy.
Data Source
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AI summary
The present application provides a battery SOC evaluation method, an apparatus, a device and a medium. The method includes: acquiring charging-discharging data of a first battery cell pack at different first temperatures and different first rates, where the number of the first battery cell pack is at least one, and the first battery cell pack includes a first battery cell; acquiring first SOCs of the first battery cell pack according to the charging-discharging data, where the charging-discharging data includes first voltages of the first battery cell pack; establishing an association table of the first SOCs with the first temperatures, the first rates and the first voltages; acquiring a second temperature, a second rate and a second voltage of a battery pack, and acquiring a second SOC of each second battery cell in the battery pack by the association table, where the battery pack includes multiple second battery cells. The method of the present application can improve the accuracy of battery SOC evaluation.