Battery State Estimation via Voltage Error Correction
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Solution Overview
Problem
Current battery management systems face challenges in accurately estimating the state of charge (SoC) and state of health (SoH) of batteries due to errors in current measurements and voltage profiles, leading to suboptimal battery operation.
Innovation Solution
A method is introduced to estimate the battery state by determining a correction value for current information using a weight based on average current values and voltage errors, which are calculated by comparing measured and estimated voltage information, and applying these corrections to discharging and charging currents to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If battery state is estimated using standard BMS methods, then the system operates with simple measurement procedures, but the estimation accuracy of SoC and SoH deteriorates due to errors in current measurements and voltage profiles
Solution Approach 1:
The patent implements a feedback mechanism where the estimated battery state (voltage, SoC, SoH) is continuously compared with actual measurements. The voltage error between estimated and measured values is used to generate correction values that are fed back to adjust current information and subsequent state estimates, creating a closed-loop system that improves accuracy over time
Solution Approach 2:
The patent introduces voltage error as an intermediary element that mediates between the estimated battery state and the actual measurements. This voltage error serves as a correction signal that indirectly adjusts current information and improves state estimation accuracy without requiring direct measurement of all battery parameters
2Measurement precision
If voltage error correction is applied to improve current information accuracy, then battery state estimation accuracy improves, but the calculation complexity and processing time increase
Solution Approach 1:
The patent performs preliminary calculations of open-circuit voltage (OCV) based on the relationship between voltage, SoC, and temperature before actual measurements are taken. This pre-calculated OCV information is used to quickly determine voltage errors and generate correction values, reducing the computational burden during real-time operation
Solution Approach 2:
The patent applies partial correction by focusing only on the voltage error component that most significantly affects state estimation accuracy. Rather than correcting all possible measurement errors, the system selectively corrects current information based on voltage discrepancies, achieving improved accuracy with reduced computational effort
Data Source
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AI summary
A method of estimating a state of a battery is disclosed. The method includes correcting electrical physical quantity information of the battery at a current time period using a correction value determined based on a voltage error of the battery from a previous time period, and determining state information of the battery based on the corrected electrical physical quantity information.