Electrolyte Impregnation Analysis via Differential Capacity Curves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for analyzing the degree of electrolyte impregnation in lithium secondary batteries are imprecise, leading to potential performance degradation and safety issues due to inadequate electrolyte penetration, especially as battery sizes increase and impregnation efficiency decreases.
Innovation Solution
A method involving the fabrication of a battery cell, repeated charging and discharging to obtain a capacity-voltage profile, differentiation to generate a differential capacity curve, and determining the cycle at which the impregnation behavior stabilizes, indicating sufficient electrolyte impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrode plates are increased in size to increase battery capacity, then battery capacity increases, but electrolyte impregnation efficiency decreases and penetration volume is reduced
Solution Approach 1:
The patent applies preliminary action by performing multiple charge/discharge cycles before the battery is considered ready for use. This pre-treatment allows the electrolyte to gradually penetrate deep into the electrode pores through repeated lithium ion insertion/extraction cycles, ensuring complete impregnation before the battery enters service. The method systematically addresses the impregnation issue by preparing the battery in advance through controlled cycling rather than attempting to force rapid penetration.
2Ease of manufacture
If electrolyte injection is performed after electrode assembly is stacked, then battery manufacturing is simplified, but electrolyte may not penetrate uniformly throughout the electrode
Solution Approach 1:
The patent employs feedback mechanisms by monitoring voltage and capacity changes during charge/discharge cycles to assess electrolyte impregnation status. The system uses differential capacity curves and voltage profile analysis to detect when uniform penetration has been achieved. This feedback loop allows manufacturers to objectively determine when impregnation is complete, ensuring uniform distribution without requiring complex injection processes or excessive electrolyte volumes.
3Ease of operation
If conventional AC impedance measurement is used to analyze electrolyte impregnation, then measurement process is simple, but analysis precision is insufficient to determine sufficient impregnation point
Solution Approach 1:
The patent replaces the conventional AC impedance measurement approach with an electrochemical method based on charge/discharge cycling and differential capacity analysis. Instead of using electrical impedance spectroscopy, the system uses voltage-capacity profiles obtained during normal charge/discharge operations to assess impregnation. This substitution maintains operational simplicity while providing significantly more precise determination of the sufficient impregnation point through characteristic curve analysis.
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
This method allows for accurate determination of electrolyte impregnation, ensuring all reactable lithium ions are intercalated, thereby maintaining battery performance and safety by identifying the point of sufficient impregnation.
Implementation Method 1
the electrolyte is injected to thereby manufacture the lithium secondary battery. At this time, the electrolyte injected later is permeated between the positive electrode, the negative electrode and the separator by a capillary force.
Implementation Method 2
lithium ions can be absorbed and desorbed to and from all active materials only when electrolytes are impregnated from several nm to several μm micro pores
Implementation Method 3
a method for precisely analyzing the degree of electrolyte impregnation of an electrode in a cell to determine at which cycle the electrolyte is sufficiently impregnated through a differential capacity curve which is obtained by differentiating a capacity-voltage profile with respect to the capacity for each charge/discharge cycle.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method for analyzing a degree of impregnation of an electrolyte of an electrode in a battery cell, the method comprising: a battery cell manufacturing step (S1) of preparing a battery cell by injecting an electrolyte into a battery cell including an electrode to be evaluated; a step of charging/discharging the battery cell several times and obtaining a capacity-voltage profile for each cycle (S2); a step of obtaining a differential capacity (dV/dQ) curve obtained by differentiating the capacitance-voltage profile for each cycle with respect to the capacity (S3); and a step of, in the differential capacity curve, determining a cycle at which behavior becomes the same as a time point when impregnation is sufficiently performed (S4).