Electrode Substrate Stretching for Uniform Compression
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Solution Overview
Problem
The existing methods for manufacturing electrodes for secondary batteries, such as nonaqueous electrolyte secondary batteries, face challenges in achieving high packing density and reliability due to creases and warpage caused by uneven compression of the substrate, particularly when the exposed regions of the substrate are not properly stretched before compression.
Innovation Solution
A method involving the separate stretching of first and second exposed regions of the substrate using different stretching rollers, followed by compression of the active material layer, ensures uniform stretching and prevents creases and warpage, thereby achieving high packing density and reliability in the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active material layer is compressed at higher pressure to increase packing density, then the volume energy density is improved, but the substrate becomes rolled and creases occur due to uneven compression
Solution Approach 1:
The exposed regions of the substrate are stretched in advance before the active material layer is formed and compressed. This preliminary stretching action prepares the substrate to accommodate subsequent compression uniformly, preventing creases and warpage while enabling high packing density
2Manufacturing precision
If the exposed regions of the substrate are stretched in advance to prevent creases, then the manufacturing precision is improved, but the stretching may not be uniform if done simultaneously on both sides
Solution Approach 1:
The stretching process is divided into sequential steps where the first exposed region is stretched separately from the second exposed region. This segmentation allows each region to be stretched independently and uniformly, ensuring consistent manufacturing precision and 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 approach allows for more reliable and uniform stretching of the substrate regions, resulting in electrodes with high packing density and reduced defects like creases and warpage, which enhances the performance and reliability of secondary batteries.
Implementation Method 1
stretching the first exposed region of the substrate after the step of forming the active material layer; stretching the second exposed region of the substrate after the first stretching step
Implementation Method 2
compressing the active material layer after the second stretching step
Data Source
AI summary
Disclosed is a method for manufacturing a positive electrode including a positive electrode substrate made of aluminum foil and a positive electrode active material layer containing a positive electrode active material on the positive electrode substrate. This method includes the steps of stretching a first exposed region of the positive electrode substrate with a first stretching roller disposed upstream; stretching a second exposed region of the positive electrode substrate with a second stretching roller disposed downstream; and compressing the positive electrode active material layer with a pair of compression rollers.