Porous Separator Adhesion Air Permeability Battery
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges with separators that either have high adhesion to electrodes but low air permeability, leading to misalignment and deteriorated battery characteristics, or high air permeability but lack adhesion, resulting in poor battery performance during assembly.
Innovation Solution
A nonaqueous electrolyte secondary battery insulating porous layer with a thermoplastic resin, porosity of 25% to 80%, and peeling strength of 0.5 N/m to 2.0 N/m when press-bonded to an electrode at room temperature, ensuring both adhesion and high air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a porous layer containing resin as main component is laminated, then adhesion to electrode is high, but air permeability is low
Solution Approach 1:
The patent applies porous materials by constructing the porous layer with a specific porous structure where inorganic filler particles are dispersed in a resin matrix, creating interconnected voids that allow air and electrolyte penetration while maintaining structural integrity and adhesion to the electrode
Solution Approach 2:
The patent uses composite materials by combining organic resin components with inorganic filler particles (such as alumina, silica, or boehmite) to create a porous layer that exhibits both adhesive properties from the resin and permeability characteristics from the composite structure, resolving the contradiction between adhesion and air permeability
2Quantity of substance
If a porous layer containing filler as main component is laminated, then air permeability is high, but adhesion to electrode is poor
Solution Approach 1:
The patent employs composite materials formulation where inorganic filler particles are dispersed within a continuous resin phase, ensuring that the resin provides the adhesive bonding to the electrode while the filler particles contribute to maintaining porosity and air permeability, thus achieving both high adhesion and high air permeability simultaneously
3Strength
If press-bonding force is increased to improve adhesion, then adhesion increases, but battery assembly precision deteriorates due to misalignment
Solution Approach 1:
The patent applies parameter changes by optimizing the adhesive properties of the porous layer through controlled resin content, filler particle size distribution, and porosity parameters, enabling adequate adhesion at reduced press-bonding forces, thereby preventing electrode misalignment during battery assembly while maintaining sufficient adhesion strength
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 porous layer achieves adhesion to electrodes while maintaining sufficient air permeability, improving battery characteristics and assembly productivity by preventing misalignment and enhancing battery performance.
Implementation Method 1
has a peeling strength of above 0 N/m to 2.0 N/m when press-bonded to a nonaqueous electrolyte secondary battery electrode
Implementation Method 2
has a porosity of 25% to 80%
Data Source
AI summary
The present invention improves productivity of production of a nonaqueous electrolyte secondary battery. A nonaqueous electrolyte secondary battery insulating porous layer in accordance with an embodiment of the present invention is a constituent member of a nonaqueous electrolyte secondary battery laminated separator, includes a thermoplastic resin, has a porosity of 25% to 80%, and has a peeling strength of above 0 N/m to 2.0 N/m when press-bonded to a nonaqueous electrolyte secondary battery electrode at 25° C. through two one-minute 30 kN applications, the nonaqueous electrolyte secondary battery electrode containing an electrode active material, an electrically conductive agent, and a binding agent in a mass fraction of 92:2.7:5.3.