Secondary Battery Electrode Thickness Profile for Fat Edge Control
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Solution Overview
Problem
The fat edge phenomenon in electrode manufacturing leads to uneven thickness distribution, causing issues like electrode side cracking, contamination of the rolling roll surface, and lithium precipitation, which affect battery safety and performance.
Innovation Solution
The electrode design includes an electrode active material layer with specific thickness profiles, defined by H1, H2, and H3 regions, where the H2 region has an inclined section increasing in thickness from H1 to H3, ensuring a balanced loading distribution and preventing fat edge issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the loading amount of electrode slurry is increased at the edge of the electrode to achieve high-density electrode, then the energy density is improved, but the fat edge phenomenon occurs causing uneven thickness distribution
Solution Approach 1:
The electrode slurry loading amount is differentiated by location: the edge region (within 10mm from the end) has a loading amount of 8-12 mg/cm², while the center region has a loading amount of 10-14 mg/cm². This local quality differentiation prevents the fat edge phenomenon by ensuring that edges do not receive excessive slurry, thereby maintaining uniform thickness distribution while achieving high energy density through optimized local loading.
2Manufacturing precision
If the overall side loading amount is reduced to prevent fat edge phenomenon, then the thickness distribution is improved, but Li precipitation occurs due to inversion of N/P ratio
Solution Approach 1:
The solution applies local quality differentiation by setting specific loading amount ranges for different regions: the edge region (within 10mm from the end) receives 8-12 mg/cm², while the center region receives 10-14 mg/cm². This ensures that the overall N/P ratio is maintained appropriately to prevent Li precipitation, while locally controlling the edge loading to prevent fat edge phenomenon and ensure uniform thickness distribution.
3Quantity of substance
If the loading amount at the edge is increased to achieve high-density electrode, then the energy density is improved, but electrode side cracking occurs during rolling process
Solution Approach 1:
The electrode slurry loading amount is differentiated by location: the edge region (within 10mm from the end) has a loading amount of 8-12 mg/cm², while the center region has a loading amount of 10-14 mg/cm². This local quality differentiation prevents excessive thickness at the edges, thereby preventing side cracking during the rolling process while maintaining high energy density through optimized local loading in the center region.
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 design effectively prevents fat edge phenomena, reduces the risk of electrode side cracking, and prevents lithium precipitation during battery charging and discharging, thereby enhancing battery safety and performance.
Implementation Method 1
coating an electrode slurry containing an electrode active material on an electrode current collector, followed by drying and rolling
Implementation Method 2
in the case in which the side loading amount is high, the pressure on the side of the electrode is increased due to the bending phenomenon of the rolling roll during the rolling process
Data Source
AI summary
Provided is a high-density electrode and a method of manufacturing the same. An electrode for a secondary battery includes an electrode current collector, and an electrode active material layer formed on at least one surface of the electrode current collector. The electrode active material layer includes an H1 region, an H2 region and an H3 region sequentially provided from an end of the electrode active material layer toward a center. The H2 region includes an inclined section in which a thickness increases from the H1 region toward the H3 region, and the electrode satisfies the following formulas (1) and (2), 0.2≤h1/h2≤0.7 . . . (1), h2/h3≥0.9 . . . (2), where h1 is an average thickness of the H1 region, h2 is an average thickness of the H2 region, and h3 is an average thickness of the H3 region.