Cathode Material Foreign-Substance Detection via Monolayer Imaging
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Solution Overview
Problem
Existing methods struggle to quickly and accurately detect the shape and composition of fine metallic foreign substances in positive electrode materials, which can cause low-voltage defects in lithium-ion batteries, particularly those smaller than 40 µm in size.
Innovation Solution
A system and method utilizing an optical microscope with a pretreatment part to create a monolayer sample, a measurement part to obtain optical images, and an analysis part to analyze these images, enhancing detection of metallic foreign substances by 40 µm or less, including a substrate, pressing member, and laser light source for compositional analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ICP-AES is used to detect metallic foreign substances, then trace amounts of foreign substances can be detected at the ppm level, but it is difficult to determine the shape of the foreign substances and identify the source of contamination
Solution Approach 1:
The patent combines ICP-AES technology with optical microscopy and image analysis to merge the advantages of both methods. The ICP-AES provides sensitive detection of metallic foreign substances at ppm levels, while the optical microscopy component captures shape and size information, thereby eliminating the information loss about foreign substance morphology that occurs when using ICP-AES alone.
2Productivity
If XRF is used to analyze foreign substances, then large quantities of active materials can be analyzed, but it has difficulty detecting foreign substances smaller than a certain size
Solution Approach 1:
The patent segments the analysis process into two distinct stages: first, optical microscopy is used to identify and locate foreign substances including fine particles based on their optical properties and shape; second, ICP-AES is applied specifically to the identified foreign substance locations for compositional analysis. This segmentation allows the system to overcome the size limitation of XRF while maintaining high productivity through targeted analysis.
3Measurement precision
If SEM-EDS is used to detect foreign particles, then both shape and composition can be confirmed and fine particles can be detected, but substantial time is required for measuring large areas
Solution Approach 1:
The patent applies partial action by using optical microscopy to perform a preliminary screening of large areas to identify regions containing foreign substances. Only the specific areas where foreign substances are detected by the optical method are then subjected to the more time-consuming SEM-EDS or ICP-AES analysis. This approach reduces the overall measurement time significantly while maintaining the ability to detect both shape and composition of fine particles.
4Productivity
If conventional optical microscopy is used to detect foreign substances, then analysis can be performed quickly, but it is difficult to detect metallic foreign substances with a size of about 40 μm or less
Solution Approach 1:
The patent introduces ICP-AES as an intermediary technique that complements optical microscopy. The optical microscopy component quickly screens samples and identifies potential foreign substance locations, while the ICP-AES system acts as an intermediary to provide sensitive detection and compositional analysis of metallic foreign substances as small as 40 μm or less, thereby enhancing the overall detection capability without sacrificing analysis speed.
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 rapid identification and characterization of metallic foreign substances, reducing analysis time and improving defect management in positive electrode materials, thereby preventing low-voltage issues.
Implementation Method 1
a measurement part configured to obtain an optical image of the monolayer sample using an optical microscope
Implementation Method 2
a laser light source for compositional analysis
Data Source
Figure 1~2
Figure 3(A)~4(B)
Figure 5(A)~5(B)
AI summary
The present invention relates to a system and method for analyzing foreign substances in a positive electrode material, the system includes a pretreatment part configured to prepare a monolayer sample of a positive electrode material powder, a measurement part configured to obtain an optical image of the monolayer sample using an optical microscope, and an analysis part configured to analyze the optical image of the monolayer sample, thereby obtaining information on foreign substances in the positive electrode material.