Wound Electrode Assembly Adhesive Layer Optimization
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Solution Overview
Problem
Existing non-aqueous electrolyte rechargeable batteries face challenges in achieving optimal energy density and cycle-life due to issues with the handling and deformation of wound electrode assemblies, particularly related to the properties of the adhesive layers on the separators, which affect the slipperiness and thermal stability.
Innovation Solution
A wound electrode assembly is designed with a belt-shaped structure, incorporating a fluorine resin-containing particulate, a binder particle, and a heat-resistant filler particle, where the average particle diameters of these components satisfy specific equations to form a thin adhesive layer, enhancing handling properties and preventing deformation, while improving energy density and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous film made of PVDF-based fluorine resin is formed on the separator surface, then the adhesive layer provides binding function, but the adhesive layer becomes thick causing deformation and poor handling properties
Solution Approach 1:
The patent changes the particle size parameters of the adhesive components. It uses fluorine resin-containing particles with average diameter of 1-10 μm, binder particles with average diameter of 0.1-1 μm, and heat-resistant filler particles with average diameter of 10-100 nm. This parameter optimization allows achieving adequate adhesive strength with a thinner adhesive layer, preventing deformation while maintaining handling properties.
Solution Approach 2:
The patent creates a composite adhesive layer containing three types of particles: fluorine resin-containing particles (for adhesive function), binder particles (for structural support), and heat-resistant filler particles (for thermal stability). This composite structure achieves multiple functions simultaneously with reduced overall thickness compared to conventional single-material adhesive layers.
2Ease of operation
If the adhesive layer is made thin to improve handling properties, then deformation is reduced, but the adhesive strength and binding function deteriorate
Solution Approach 1:
The patent optimizes particle size parameters to enhance adhesive efficiency. The fluorine resin-containing particles (1-10 μm) provide strong adhesive bonding, while the small binder particles (0.1-1 μm) create a dense network structure. This parameter combination enables thin adhesive layers to maintain adequate adhesive strength while improving handling properties.
Solution Approach 2:
The patent assigns different functional roles to different particle types within the adhesive layer. The fluorine resin-containing particles are concentrated at the interface with the porous film to provide localized adhesive strength, while the binder particles form a supporting matrix throughout the layer. This local quality differentiation allows thin layers to achieve sufficient binding function.
3Ease of manufacture
If conventional adhesive layer composition is used, then manufacturing is simple, but energy density is insufficient due to excessive thickness
Solution Approach 1:
The patent uses a composite particle system that can be prepared by conventional mixing and coating methods, maintaining manufacturing simplicity. The composite structure with fluorine resin-containing particles, binder particles, and heat-resistant filler particles achieves reduced thickness and improved energy density without requiring complex manufacturing processes.
4Ease of manufacture
If the adhesive layer lacks heat-resistant filler, then manufacturing is easier, but thermal stability and heat resistance are insufficient
Solution Approach 1:
The patent incorporates heat-resistant filler particles (10-100 nm) into the adhesive layer composite. These particles provide thermal stability and heat resistance while being easily mixed with other adhesive components using conventional methods, adding minimal complexity to the manufacturing process.
Data Source
AI summary
A wound electrode assembly for a non-aqueous electrolyte rechargeable battery, the wound electrode assembly including a positive electrode, a negative electrode, and a porous film between the positive electrode and negative electrode, the positive electrode, the negative electrode, and the porous film each being belt-shaped, and an adhesive layer on the surface of the porous film. The adhesive layer includes a fluorine resin-containing particulate, a binder particle supporting the fluorine resin-containing particulate and having a smaller total volume than that of the fluorine resin-containing particulate, and a heat-resistant filler particle. An average particle diameter of the binder particle is about 100 nm to about 500 nm. An average particle diameter of the heat-resistant filler particle is about 10 nm to about 100 nm.