Mixed-Anode Battery Cell Active Area Diagnosis Using EIS and DRT
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Solution Overview
Problem
Existing methods struggle to determine the optimal state of charge at which components in a mixed anode of a battery cell, such as SiO and graphite, are dominantly activated, leading to potential durability issues.
Innovation Solution
A method using electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) to analyze impedance changes based on state of charge, identifying active areas of a mixed anode by calculating resistance ratios and determining dominant components through impedance graphs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If SiO component is used in mixed anode to improve energy density, then energy density is improved, but durability deteriorates due to excessive reaction depth concentration
Solution Approach 1:
The patent applies parameter changes by analyzing impedance spectroscopy data across different states of charge to determine the optimal reaction depth parameter. By measuring impedance at various charge levels and calculating the depth of use distribution, the system identifies the state of charge where SiO component reaction depth is optimized - deep enough to achieve high energy density but controlled to prevent excessive depth concentration that would harm durability.
2Reliability
If EIS analysis is performed to analyze battery cell, then non-destructive analysis is achieved, but difficulty in detecting and measuring increases due to complex impedance data interpretation
Solution Approach 1:
The patent introduces distribution of relaxation times (DRT) as an intermediary method to simplify EIS data interpretation. Instead of directly analyzing complex impedance spectra, the system converts impedance data into DRT distribution, which separates different electrochemical processes into distinct time constants. This intermediary transformation makes it easier to identify and measure the contribution of specific components (SiO vs graphite) to the overall impedance, reducing the difficulty of detection and measurement.
Solution Approach 2:
The patent replaces the complex mechanical/physical interpretation of impedance data with an equivalent circuit model approach. By substituting the direct analysis of impedance spectra with an equivalent electrical circuit representation (using resistors, capacitors, and constant phase elements), the system simplifies the measurement interpretation process. The equivalent circuit model provides a intuitive framework for understanding battery cell behavior without requiring complex mathematical analysis of raw impedance data.
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 accurate determination of battery cell durability by identifying the state of charge where each component is dominantly active, allowing for improved battery cell design and performance.
Implementation Method 1
One of various technologies in the related art used to analyze the battery cell is electrochemical impedance spectroscopy (EIS). The EIS is an analysis method of applying an alternating current voltage or an alternating current in various frequencies, calculating impedance based on an alternating current or alternating voltage measured as a result of the applying
Implementation Method 2
One of technologies in the related art used to further easily analyze a result of the EIS is distribution of relaxation times (DRT). The DRT is widely used in that impedance data calculated as a result of the EIS may be converted into a distribution of relaxation times so that an equivalent circuit of a battery may be identified
Data Source
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AI summary
Disclosed are a method for diagnosing, by a server, an active area of a battery cell including a mixed negative electrode in which a first component and a second component are mixed, and the server. This method comprises the steps of: acquiring impedance information of a target battery cell to be diagnosed, by performing electrochemical impedance spectroscopy on the battery cell; acquiring, on the basis of the impedance information, information about a change in impedance according to a frequency; and diagnosing an active area of the target battery cell on the basis of the information about the change in impedance.