Photocured PSA Electrode Stack for Low-Pressure Battery Lamination
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Solution Overview
Problem
Conventional lithium secondary battery manufacturing processes face issues such as electrode cracking, short circuits, and reduced yield due to high heat and pressure requirements for adhesive force between electrodes and separators, and the use of separate separators like SRS separators increases costs and process time.
Innovation Solution
An all-in-one electrode stack unit integrates an electrode and a photocured pressure-sensitive adhesive (PSA) separation layer with specific mechanical and adhesive properties, eliminating the need for a separate separator, using a polymer coating layer with ceramic particles and a patterned structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate separators and electrodes are laminated using high heat and pressure, then adhesive force between separator and electrode is ensured, but electrode distortion and active material cracking occur
Solution Approach 1:
The separator and electrode are merged into a single integrated structure where the separator serves dual functions as both separation medium and adhesive layer. The photocured PSA coating is applied directly to the electrode surface, eliminating the need for separate lamination of distinct separator and electrode components, thereby preventing distortion while maintaining adhesive force.
Solution Approach 2:
The lamination process parameters are changed from high heat and pressure to low heat and pressure conditions. The photocured PSA coating enables adhesion through photopolymerization rather than thermal bonding, allowing lamination at temperatures below the degradation point of active materials while achieving sufficient adhesive force.
2Reliability
If separate separators are manufactured and applied, then heat resistance and strength are ensured, but process time increases and cost increases
Solution Approach 1:
The separator functions are merged with the adhesive layer functions. The photocured PSA coating performs both the separation function and the adhesive function simultaneously, eliminating the need for separate separator manufacturing and application processes, thereby reducing process time while maintaining heat resistance through proper material selection.
Solution Approach 2:
The separator is designed to perform multiple functions: ion separation, mechanical support, and adhesive bonding. By making the separator multi-functional, the number of separate components and processes is reduced, streamlining manufacturing while ensuring reliable heat resistance and strength through the inherent properties of the separator material.
3Strength
If high heat and pressure are used for lamination, then adhesive force is ensured, but yield reduces due to short circuit defects
Solution Approach 1:
The lamination parameters are changed from high heat and pressure to low heat and pressure with photocuring. This parameter change prevents active material degradation and short circuit defects that occur with excessive heat, thereby maintaining high yield while achieving sufficient adhesive force through photopolymerization of the PSA coating.
Solution Approach 2:
The thermal-mechanical lamination system is replaced with a photochemical bonding system. Instead of relying solely on heat and pressure to create adhesion, the photocured PSA coating uses light-induced polymerization to form strong bonds, reducing mechanical stress on the electrode structure and preventing defects that lead to short circuits.
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 integration enhances adhesive force, improves safety, and reduces manufacturing defects, simplifying the process while maintaining high yield and performance.
Implementation Method 1
the separation layer is a photocured pressure sensitive adhesive (PSA) coating layer integrally formed on the first electrode
Data Source
AI summary
An all-in-one electrode stack unit includesa first electrode, a second electrode, and a separation layer interposed between the first electrode and the second electrode.The separation layer is a photocured PSA coating layer integrally formed on the first electrode.The separation layer has a strength of 30 to 50 MPa and an adhesive force to the second electrode of 70 gf/20 mm to 90 gf/20 mm.The first electrode, the separation layer, and the second electrode are laminated. The electrode stack unit is manufactured by a method. A lithium secondary battery includes the electrode stack unit.