Compacted Strip Electrode Plate Wrinkle Reduction
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Solution Overview
Problem
The existing manufacturing method of compacted strip-shaped electrode plates often results in wrinkling of the current collector foil near the boundary between the active material section and the exposed section due to differences in thickness and pressure distribution during the rolling process, leading to reduced reliability in lithium-ion secondary batteries.
Innovation Solution
A manufacturing method that incorporates a mixed particle aggregate with varying content ratios of conductive particles, creating elongated regions of different hardness, which are randomly distributed in the active material layer, allowing for reduced wrinkling by distributing pressure more evenly during the rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the active material layer and current collector foil are pressed by rollers while being conveyed in the longitudinal direction, then the active material layer is compacted in the thickness direction, but the current collector foil wrinkles near the boundary between the active material section and the exposed section
Solution Approach 1:
The patent applies local quality by creating regions with different conductive particle content ratios within the active material layer. Specifically, it forms a first region with a first content ratio of conductive particles and a second region with a second content ratio different from the first. This non-uniform distribution creates local variations in hardness and compressibility, allowing different parts of the active material layer to respond differently to the pressing force, thereby preventing wrinkles in the current collector foil while maintaining effective compaction.
2Ease of manufacture
If the active material layer is made uniformly thick, then the pressing process is simplified, but the current collector foil stretches unevenly causing wrinkles at the boundary with the exposed section
Solution Approach 1:
The patent introduces local quality variations through different conductive particle content ratios in different regions of the active material layer. This creates zones with different mechanical properties (hardness, compressibility) that can be optimized for their specific functions: one region may be softer to accommodate stretching without wrinkling, while another region maintains uniform thickness for simplified processing. This resolves the contradiction between manufacturing simplicity and structural reliability.
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 effectively reduces wrinkling of the current collector foil, enhancing the reliability and performance of the compacted strip-shaped electrode plates and subsequently the batteries they are used in by ensuring even pressure distribution and minimizing structural defects.
Implementation Method 1
an active material layer that is formed on the current collector foil in a shape of a strip extending in a longitudinal direction of the current collector foil, contains active material particles and conductive particles, and is compacted by being pressed in a thickness direction of the current collector foil
Implementation Method 2
a manufacturing method includes: an undried layer forming step of forming, on the current collector foil, an undried active material layer having a shape of a strip extending in the longitudinal direction by rolling out, in the longitudinal direction, a particle aggregate that is an aggregate of wet particles including the active material particles, the conductive particles, and a dispersion medium; a drying step of drying the undried active material layer on the current collector foil to form the active material layer
Data Source
AI summary
Provided is a manufacturing method of a compacted strip-shaped electrode plate including: an undried layer forming step of forming, on a current collector foil, a strip-shaped undried active material layer by rolling out a particle aggregate; a drying step of drying the undried active material layer to form an active material layer; and a pressing step of pressing the active material layer by rollers to compact the active material layer. The particle aggregate is a mixed particle aggregate in which first wet particles manufactured with the content ratio of conductive particles to the total solid content set to W1 and second wet particles manufactured with the content ratio of conductive particles to the total solid content set to W2, W2 being higher than W1, are mixed together.