Li-Ion Electrodeposition Detection via Positive-Electrode SOC Mapping
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Solution Overview
Problem
Existing methods for detecting lithium electrodeposition in lithium-ion batteries only determine the presence or absence of the phenomenon, failing to provide insights into its plane distribution, which hinders effective prevention and control.
Innovation Solution
Generate a positive-electrode SOC map through X-ray diffraction of the positive-electrode active material layer to detect the plane distribution of lithium electrodeposition, using a high-energy X-ray to calculate the SOC difference value, and compare it with a threshold to determine the occurrence of lithium electrodeposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods (local minimum point detection, voltage change rate detection, case thickness detection) are used, then the presence or absence of lithium electrodeposition can be detected, but the plane distribution of lithium electrodeposition in the negative-electrode active material layer cannot be comprehended
Solution Approach 1:
The invention transitions from detecting only the presence/absence of lithium electrodeposition (0D or 1D measurement) to mapping the plane distribution across the electrode surface (2D measurement). By moving the detector in the X-direction along the width of the positive-electrode active material layer and measuring at multiple positions, the system creates a two-dimensional distribution map that reveals spatial variations in lithium electrodeposition that conventional single-point methods cannot detect.
Solution Approach 2:
The invention uses X-ray diffraction to create a indirect copy or map of the lithium electrodeposition distribution in the negative electrode by measuring the corresponding positive electrode's SOC distribution. Since directly detecting lithium metal in the negative electrode is difficult, the method copies the information through the coupled electrochemical system, where the positive electrode's SOC map reflects the lithium electrodeposition state in the negative electrode.
2Reliability
If charging is performed within a preset upper limit voltage to prevent lithium electrodeposition, then capacity degradation can be reduced, but the charging amount and regeneration output are reduced compared to new batteries
Solution Approach 1:
The invention performs preliminary detection of lithium electrodeposition using X-ray diffraction before capacity degradation becomes severe. By detecting the plane distribution and identifying regions with high lithium electrodeposition risk, the system can take preventive actions such as adjusting charging rates in specific areas or modifying overall charging strategies, thereby preventing degradation while maintaining higher charging amounts than conservative preset voltage limits would allow.
Solution Approach 2:
The invention implements a feedback mechanism where the detected plane distribution of lithium electrodeposition is used to dynamically adjust charging control strategies. The system continuously monitors the SOC distribution map and lithium electrodeposition state, then feeds this information back to optimize charging parameters, enabling higher charging amounts and regeneration output while preventing capacity degradation through real-time adjustments rather than static voltage limits.
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 prediction of lithium electrodeposition, thereby improving energy efficiency by preventing capacity degradation and extending the battery's lifetime through controlled charging conditions.
Implementation Method 1
performing an X-ray diffraction measurement of the positive-electrode active material layer
Data Source
AI summary
A lithium-ion battery electrodeposition detection method includes: a positive-electrode SOC map generation step of irradiating a lithium-ion battery with an X-ray, performing an X-ray diffraction measurement of a positive-electrode active material layer, and generating a positive-electrode SOC map that indicates a distribution of a charging depth along a thickness direction of the positive-electrode active material layer; a SOC difference value detection step of detecting a SOC difference value which is a difference between a maximum value and a minimum value of the positive-electrode SOC map; and a determination step of comparing the SOC difference value with a preset threshold value and determining a presence or absence of a lithium electrodeposition of a negative-electrode active material layer.