Patterned Plasma Roller for Battery Separator Wettability
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Solution Overview
Problem
Conventional secondary battery manufacturing processes result in reduced wettability between electrodes and separators due to uniform adhesive forces, leading to degraded battery performance and potential lithium plating from gas buildup.
Innovation Solution
A plasma processing apparatus is introduced, featuring a discharge roller with a patterned surface that alternates between contact and non-contact portions, allowing for a patterned adhesive force on the separator surfaces. This apparatus generates plasma to treat the separator surfaces, creating areas with varying adhesive forces to improve electrolyte wettability and gas discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If uniform adhesive force is applied between electrode and separator, then lamination strength is improved, but electrolyte wettability deteriorates
Solution Approach 1:
The discharge roller surface is designed with a patterned structure comprising protruding portions and recessed portions, creating local variations in adhesive force. The protruding portions provide strong adhesion for lamination strength, while the recessed portions provide weak adhesion to maintain electrolyte wettability. This local differentiation resolves the contradiction between uniform strength and localized wettability requirements.
2Strength
If strong adhesive force is applied between electrode and separator, then lamination strength is improved, but gas discharge capability deteriorates
Solution Approach 1:
The patterned discharge roller creates localized weak adhesion zones in the recessed portions where gas can accumulate and escape during battery formation. These localized weak zones serve as gas discharge pathways while the surrounding strong adhesion zones maintain overall lamination integrity, resolving the contradiction between strong bonding and gas discharge requirements.
3Productivity
If constant temperature and pressure are used in lamination process, then manufacturing efficiency is improved, but electrolyte permeability deteriorates
Solution Approach 1:
Instead of using complex variable temperature and pressure control systems during lamination, the patent replaces this mechanical control approach with a fixed geometric pattern on the discharge roller. The patterned structure inherently creates the desired adhesive force distribution without requiring dynamic process adjustments, maintaining manufacturing efficiency while achieving good electrolyte permeability through the weak adhesion zones.
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 plasma processing apparatus enhances electrolyte wettability by creating areas with weak adhesive forces between electrodes and separators, thereby improving battery performance and preventing lithium plating by ensuring smooth gas discharge.
Implementation Method 1
a plasma processing member configured to generate plasma through a mutual reaction with the metal member and irradiate the plasma to a surface of the separator
Data Source
AI summary
A plasma processing apparatus of a unit cell for a secondary battery includes a discharge roller configured to transport a separator of the unit cell for a secondary battery and allowing a metal member to be placed therein, and a plasma processing member configured to generate plasma through a mutual reaction with the metal member and irradiate the plasma to a surface of the separator, wherein a pattern portion having a certain stepped portion is formed on an outer surface of the discharge roller.