Battery Temperature Estimation Using EIS Lookup Tables
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Solution Overview
Problem
Existing methods for determining battery temperature, such as using temperature sensors or impedance analysis alone, are inaccurate and inefficient, especially as batteries age, leading to challenges in maintaining safety and performance.
Innovation Solution
A method utilizing electrochemical impedance spectroscopy (EIS) to obtain impedance values and state values of a battery, updating a lookup table with these values over time, and determining temperature based on the table when complete, allowing for accurate temperature measurement by interpolating or using reference values when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors or single-point impedance analysis are used to measure battery temperature, then the measurement process is simple, but the measurement precision deteriorates especially as batteries age
Solution Approach 1:
The patent performs preliminary electrochemical impedance spectroscopy (EIS) measurements and state of charge (SoC) assessments to build a comprehensive lookup table before actual temperature determination. This preliminary data collection enables accurate temperature measurement without requiring complex real-time calculations, resolving the contradiction between precision and complexity.
Solution Approach 2:
The patent introduces a lookup table as an intermediary structure that stores pre-computed relationships between impedance values, state of charge, and temperature. This intermediary enables accurate temperature determination by correlating multiple parameters rather than relying on single-point measurements, thereby improving precision while keeping the actual measurement process relatively simple.
2Measurement precision
If a comprehensive lookup table with multiple battery states is maintained, then temperature determination accuracy improves, but the amount of data storage and processing complexity increases
Solution Approach 1:
The patent segments the lookup table into different regions corresponding to various battery states (charge levels, health states, power states). This segmentation allows the system to maintain comprehensive temperature data across different operating conditions while organizing the data efficiently, reducing the computational burden of searching and processing the entire table.
Solution Approach 2:
The patent applies local quality by maintaining different levels of data detail for different battery state regions in the lookup table. High-precision temperature data is maintained for critical operating regions, while less critical regions use coarser data resolution, optimizing the balance between accuracy and storage requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables more accurate battery temperature measurement as batteries age, improving safety and performance by using a lookup table to correlate impedance and state values, reducing reliance on single-point measurements.
Implementation Method 1
a first reference temperature measurement value measured at the first time point using a temperature sensor in relation to the temperature of the target battery
Implementation Method 2
by performing electrochemical impedance spectroscopy (EIS) on the target battery at the first time point, obtaining a first impedance value of the target battery at the first time point
Data Source
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AI summary
This method, performed by an electronic device, for determining a temperature of a subject battery includes the steps of: acquiring a first state value of the subject battery at a first time point and a first reference temperature measurement value measured at the first time point by using a temperature sensor in relation to the temperature of the subject battery; acquiring a first impedance value of the subject battery at the first time point by performing electrochemical impedance spectroscopy with respect to the subject battery at the first time point; updating a lookup table area corresponding to state values of the subject battery at a first time point and a second time point subsequent to the first time point, reference temperature measurement values of the subject battery, and impedance values of the subject battery; determining whether the lookup table has been updated to a predefined completeness or more; and when the lookup table has been updated to the predefined completeness or more, determining the temperature of the subject battery on the basis of the lookup table.