Nondestructive Lithium-Ion Battery Degradation Analysis via Reference Electrode
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Solution Overview
Problem
Current methods for analyzing lithium ion battery cells struggle to nondestructively obtain information about the usage regions of individual electrodes, making it difficult to determine their degradation and capacity changes without disassembling the cell or using a reference electrode, which can alter electrochemical characteristics.
Innovation Solution
An apparatus with a sensing unit to measure full-cell open circuit voltage and current, and a control unit that estimates electrode usage regions and calculates capacity changes based on state of health (SOH) data, allowing for nondestructive determination of positive and negative electrode capacities without a reference electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference electrode is inserted to obtain electrode usage region information, then measurement precision is improved, but device complexity and reliability deteriorate due to manufacturing difficulties and altered electrochemical characteristics
Solution Approach 1:
The patent introduces a reference electrode as an intermediary element to enable precise measurement of electrode usage regions. The reference electrode serves as a mediator that allows comparison of electric potentials between positive and negative electrodes without directly interfering with their electrochemical reactions, thus achieving measurement precision while minimizing impact on reliability
Solution Approach 2:
The patent segments the battery cell into three distinct electrodes (positive electrode, negative electrode, and reference electrode) to enable independent measurement of each electrode's usage region. This segmentation allows for separate potential measurements and capacity calculations for each electrode, providing detailed degradation information without requiring cell disassembly
2Measurement precision
If a reference electrode is inserted to obtain electrode usage region information, then measurement precision is improved, but ease of manufacture deteriorates due to manufacturing complexity
Solution Approach 1:
The reference electrode is incorporated during the preliminary manufacturing stage of the battery cell, rather than being added later through disassembly. This preliminary action integrates the reference electrode into the cell structure from the beginning, simplifying the overall manufacturing process and avoiding complex post-manufacturing modifications while maintaining measurement precision
3Ease of operation
If conventional nondestructive analysis is used, then ease of operation is improved, but measurement precision deteriorates due to inability to obtain individual electrode information
Solution Approach 1:
The reference electrode acts as a mediator that enables precise measurement of individual electrode potentials while maintaining the nondestructive nature of the analysis. By providing a stable reference potential, it allows the system to calculate usage regions for each electrode without disassembling the cell, thus preserving ease of operation while achieving high measurement precision
Data Source
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AI summary
Provided are an apparatus and method of obtaining degradation information of a lithium ion battery cell. The apparatus according to an embodiment estimates a first positive electrode usage region related to a first state of health of the lithium ion battery cell. The apparatus estimates a second positive electrode usage region related to a second state of health of the lithium ion battery cell. Then, the apparatus calculates an amount of change of maximum storage capacity of a positive electrode of the lithium ion battery cell with respect to a usage period from the first state of health to the second state of health, based on the first positive electrode usage region and the second positive electrode usage region.