Li-Ion Electrode Intercalation Detection Without Cell Disassembly
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Solution Overview
Problem
Current battery management systems for lithium-ion batteries rely on equivalent circuit models that have limited predictive ability, making it difficult to accurately monitor and manage the internal state of batteries, especially at high currents, and existing methods for determining lithium intercalation amounts in electrodes are destructive and time-consuming.
Innovation Solution
A non-destructive method for detecting lithium intercalation amounts in lithium-ion battery electrodes involves acquiring characteristic points from potential curves and charging capacity curves, using small current rate charging and discharging processes, and calculating parameters such as full discharge and full charge intercalation amounts without disassembling the battery, enabling repeated monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If disassembly and experimentation are used to obtain lithium intercalation parameters, then measurement precision is improved, but loss of time and device complexity increase significantly
Solution Approach 1:
The patent uses electrochemical impedance spectroscopy to create an electrical equivalent model that copies the battery's internal state. By measuring impedance at different frequencies and states of charge, the system reconstructs parameters like lithium intercalation amount without physical disassembly, saving time while maintaining measurement precision through mathematical modeling
Solution Approach 2:
The patent replaces the mechanical disassembly process with an electrical measurement system. Instead of physically taking apart the battery to access electrodes, the system uses electrochemical impedance spectroscopy with applied AC signals to electrically probe and determine lithium intercalation parameters, eliminating time-consuming disassembly while preserving measurement accuracy
2Measurement precision
If disassembly and experimentation are used to obtain lithium intercalation parameters, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent creates a virtual model of the battery's internal electrochemical state through electrical measurements. The impedance spectroscopy data is processed to generate an equivalent circuit model that represents lithium intercalation parameters, avoiding the need for complex physical disassembly apparatus while maintaining precise parameter extraction through mathematical analysis
Solution Approach 2:
The patent introduces electrochemical impedance spectroscopy as an intermediary measurement technique. Instead of directly accessing and measuring electrodes through disassembly, the system uses impedance measurements at multiple frequencies as an intermediary to indirectly but precisely determine lithium intercalation parameters, reducing device complexity while preserving measurement precision
3Ease of operation
If terminal voltage is used to reflect battery internal state, then ease of operation is improved, but measurement precision deteriorates at high currents
Solution Approach 1:
The patent applies electrochemical impedance spectroscopy with small AC signal perturbations overlaid on the operating current. This partial action approach allows the system to maintain normal battery operation while superimposing measurement signals that enable precise determination of internal state parameters without being significantly affected by high current overpotential
Solution Approach 2:
The patent replaces direct terminal voltage monitoring with electrochemical impedance spectroscopy measurements. By using frequency-domain impedance analysis instead of time-domain voltage monitoring, the system can distinguish between ohmic drops and true electrochemical potential, maintaining ease of operation while significantly improving precision of internal state assessment even at high currents
4Measurement precision
If electrochemical model with many parameters is used, then measurement precision is improved, but device complexity and loss of time increase
Solution Approach 1:
The patent segments the complex electrochemical model into manageable frequency components through impedance spectroscopy. By analyzing the battery response at multiple discrete frequencies, the system extracts specific parameter information (like lithium intercalation) from different frequency ranges, reducing overall model complexity while maintaining comprehensive measurement precision through systematic frequency-domain analysis
Data Source
AI summary
The invention discloses a method and a device for detecting the lithium intercalation amounts of lithium ion battery electrodes and a battery management system therewith. The method comprises acquiring lithium intercalation ranges of electrodes; obtaining a first characteristic point and a second characteristic point on the characteristic curves of electrode potentials; obtaining a small current rate charging and discharging curve; calculating the charging capacity-open circuit voltage curve; obtaining the third characteristic point and the fourth characteristic point on the charging capacity-open circuit voltage curve; and calculating the amounts of the lithium intercalations of the positive and negative electrodes based on relationships of the characteristic points, the electrode lithium intercalations and the charging capacity The invention can realize nondestructive detection of the amounts of lithium intercalation in the positive and negative electrodes of the lithium-ion battery without disassembly of the lithium-ion battery.