Separator Manufacturing via Corona Lamination and Delamination
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Solution Overview
Problem
Current methods for manufacturing separators for electrochemical devices, such as lithium secondary batteries, are inefficient and economically undesirable, particularly when attempting to coat both surfaces of porous substrates with organic-inorganic composite layers to enhance safety by preventing thermal shrinkage and short-circuiting.
Innovation Solution
A method involving corona discharge treatment of porous substrates for lamination, followed by coating with an inorganic particle and binder polymer slurry on both surfaces, and subsequent delamination to produce two separators simultaneously, while maintaining porosity and reducing surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dip coating is used to form organic-inorganic coating layers on both surfaces of porous substrate simultaneously, then safety problems are solved, but manufacturing efficiency is reduced and economic desirability deteriorates
Solution Approach 1:
The patent divides the manufacturing process into separate steps: first forming the organic-inorganic coating layer on one surface, then flipping the substrate and forming another coating layer on the opposite surface. This segmentation allows each coating operation to be performed independently, improving manufacturing efficiency while maintaining the safety benefits of dual-sided coating.
Solution Approach 2:
Instead of simultaneously coating both surfaces in a single dip coating operation, the patent inverts the approach by sequentially coating one surface at a time. The substrate is flipped between coating operations, transforming a single-step simultaneous process into a multi-step sequential process that enhances productivity.
2Reliability
If thermal shrinkage prevention is achieved by coating both surfaces with inorganic particles, then short-circuiting is prevented, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct stages: substrate preparation, first coating application, drying, flipping, and second coating application. This segmentation simplifies each individual step while achieving the comprehensive safety coverage of dual-sided coating, reducing overall manufacturing complexity.
Solution Approach 2:
The patent applies preliminary action by fully coating one surface and allowing it to dry before proceeding to the other surface. This preliminary completion of one side's coating reduces the complexity of coordinating simultaneous dual-sided coating operations.
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 enhances productivity and ensures the safety of electrochemical devices by preventing short-circuiting and maintaining porosity, thus improving the performance and safety of lithium secondary batteries.
Implementation Method 1
treating at least one of the laminating surfaces of two porous substrates by corona discharge
Data Source
AI summary
A method for manufacturing separators includes (S1) treating at least one of the laminating surfaces of two porous substrates by corona discharge and laminating the porous substrates, (S2) preparing a slurry containing inorganic particles dispersed therein and a solution of a binder polymer in a solvent, and coating the slurry on both surfaces of the laminate of the porous substrates, and (S3) delaminating the coated laminate of the porous substrates. According to the method, two separators can be simultaneously manufactured with enhanced productivity. In addition, corona discharge can reduce damage to the surfaces of the porous substrates during lamination while maintaining the porosities of the porous substrates. Therefore, excellent performance of electrochemical devices using the separators can be ensured.