Auxiliary Roll Pressing for Uniform Laminate Density Transitions
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Solution Overview
Problem
Conventional laminate structures experience a low volume density region during the transition from one region to another when pressed using a roll press device, leading to degradation in capacitance and cycling characteristics, particularly in lithium ion secondary batteries.
Innovation Solution
A laminate structure with a substrate having a first and second layer, where the end portions of the layers are inclined or have a stair shape, and a roll press device with an auxiliary roll positioned above or below a virtual plane to prevent the occurrence of low volume density regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous press is performed from the first region to the second region by a pair of press rolls, then the laminate structure can be efficiently produced, but a low volume density region occurs in the transition area causing degradation in capacitance and cycling characteristics
Solution Approach 1:
The press operation is divided into two distinct stages: a first press operation in the first region that stops before reaching the second region, and a second press operation in the second region. This segmentation prevents the formation of low volume density regions at the transition area by avoiding continuous pressing through the boundary zone, thereby maintaining uniform volume density while still enabling efficient production through automated coordination of the two press operations.
2Productivity
If the press operation continues through the transition region, then production flow is maintained, but the press state of the first layer in the first region adjacent to the second region differs from other regions creating volume density variations
Solution Approach 1:
The first press operation is designed to stop at a predetermined position before reaching the second region, performing the pressing action in advance only in the first region. This preliminary action prevents the harmful effect of continuous pressing through the transition area, avoiding volume density reduction and ensuring reliable capacitance and cycling characteristics while maintaining production efficiency through coordinated operation with the second press operation.
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
The solution effectively prevents the formation of low volume density regions, ensuring consistent volume density across the laminate structure and improving the performance and reliability of lithium ion secondary batteries.
Implementation Method 1
a roll press device with an auxiliary roll positioned above or below a virtual plane to prevent the occurrence of low volume density regions
Implementation Method 2
the end portions of the layers are inclined or have a stair shape
Data Source
AI summary
A roll press device is provided and includes a pair of press rolls; and an auxiliary roll that is disposed on at least one of upstream and downstream of the pair of press rolls, wherein the roll press device is configured to press a laminate structure by allowing the laminate structure to pass between the pair of press rolls, and wherein a laminate structure contact surface of the auxiliary roll is positioned above or below a virtual plane that the laminate structure includes when the laminate structure passes between the pair of press rolls.