Battery State Estimation Using Overvoltage Profiles for Unusable SOC
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Solution Overview
Problem
Existing battery management systems face challenges in accurately predicting the unusable state of charge (SOC) due to variations in current intensity, temperature, and aging, which affects the available capacity and operational time of devices.
Innovation Solution
An electronic device equipped with temperature and current sensors, along with a processor, estimates a temperature profile using a simplified electrochemical model, converts it to an overvoltage profile, corrects it based on current SOC and voltage, and calculates unusable SOC by subtracting the corrected overvoltage from an OCV profile, thereby enhancing accuracy and reducing computational cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a simplified electrochemical model is used to estimate temperature profile, then computational cost is reduced, but measurement precision of battery state may be affected
Solution Approach 1:
The patent transforms the temperature profile estimation problem into an overvoltage profile estimation problem by changing the measurement parameter. Instead of directly measuring temperature, the system estimates overvoltage which correlates with temperature effects, thereby reducing computational complexity while maintaining estimation accuracy for unusable SOC.
Solution Approach 2:
The patent introduces overvoltage as an intermediary parameter between temperature and SOC estimation. The overvoltage profile serves as a mediator that captures temperature effects without requiring direct temperature measurement and complex thermal modeling, simplifying the overall estimation process.
2Measurement precision
If temperature profile estimation is performed continuously, then accuracy of unusable SOC estimation is improved, but computational load increases
Solution Approach 1:
The patent applies partial action by estimating only the overvoltage profile component related to temperature effects rather than performing complete temperature profile estimation. This partial estimation is sufficient for determining unusable SOC without the full computational burden of continuous temperature modeling.
Solution Approach 2:
The patent segments the SOC estimation process into usable SOC and unusable SOC components. The overvoltage profile estimation specifically addresses the unusable portion, allowing the system to focus computational resources only where needed for accurate battery management.
3Measurement precision
If correction based on current SOC and voltage is applied, then estimation accuracy is improved, but processing time increases
Solution Approach 1:
The patent implements feedback by using measured current SOC and voltage values to correct the estimated overvoltage profile. This feedback mechanism improves accuracy by comparing estimated parameters with actual measurements and adjusting the overvoltage profile accordingly, ensuring reliable unusable SOC estimation.
Data Source
AI summary
An electronic device for estimating a battery state and an operating method thereof are disclosed. The electronic device including a temperature sensor configured to measure a temperature of the battery, a current sensor configured to measure a current of the battery, a voltage sensor configured to measure a voltage of the battery, and a processor configured to estimate a temperature profile of the battery based on the temperature and the current of the battery and a battery model, determine an overvoltage profile of the battery based on the temperature profile, revise the overvoltage profile based on a current state of charge (SOC) and the voltage of the battery, and estimate an unusable SOC of the battery based on the revised overvoltage profile and an open circuit voltage (OCV) profile of the battery.