Insulation Paste for Li-Ion Battery Current Collector
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Solution Overview
Problem
Existing insulation pastes for lithium-ion secondary battery current collectors have poor storage stability, viscosity issues, and adhesion problems, leading to insufficient appearance and increased risk of short circuits due to poor adhesion to the current collector.
Innovation Solution
A specialized insulation paste comprising an inorganic filler, a binder, and a dispersion resin with specific viscosity and molecular weight characteristics, along with a solvent, is applied to the current collector, resulting in improved adhesion and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulation paste is used, then the insulation layer can be formed, but the paste has poor storage stability and viscosity control leading to insufficient appearance
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity of the insulation paste to specifically 1500 mPa·s or more, and controlling the TI value to greater than 1. These precise parameter specifications resolve the contradiction by ensuring the paste maintains stable flow characteristics during storage (improving reliability) while remaining coatable to achieve good appearance quality.
Solution Approach 2:
The patent uses composite materials by formulating the insulation paste with specific components including inorganic filler (alumina, silica, or boehmite), binder (polyvinylidene fluoride), and dispersion resin (acrylic resin with polar groups). This composite formulation improves storage stability while maintaining appearance quality through synergistic material interactions.
2Strength
If physical load is applied during pressing, then the insulation layer may fall off, but adhesion is needed to maintain insulation properties
Solution Approach 1:
The patent applies parameter changes by specifying the adhesion strength of the insulation layer to be 2.5 N/m or more. This quantitative parameter control ensures the insulation layer maintains strong adhesion during pressing operations, preventing it from falling off while preserving insulation stability.
Solution Approach 2:
The patent uses composite materials with polyvinylidene fluoride binder and acrylic resin dispersion containing polar groups (phosphate, carboxyl, or hydroxyl groups) that enhance adhesion to the current collector. This composite formulation ensures the insulation layer withstands mechanical stress during pressing while maintaining insulation properties.
3Ease of operation
If high load is applied during production, then the insulation layer may be removed or come off, but the layer is needed to prevent short circuits
Solution Approach 1:
The patent applies parameter changes by controlling the viscosity to 1500 mPa·s or more and TI value to greater than 1, which provides excellent coating workability during application while ensuring the insulation layer remains intact during subsequent high-load production steps. The adhesion strength is specified as 2.5 N/m or more to prevent removal during pressing and handling.
Solution Approach 2:
The patent uses composite materials comprising inorganic filler (alumina, silica, or boehmite with specific particle size distribution), polyvinylidene fluoride binder, and acrylic resin dispersion with polar groups. This composite structure provides both ease of coating application and reliable insulation performance under mechanical stress.
Data Source
AI summary
An insulation paste for a current collector for a lithium-ion secondary battery contains an inorganic filler (A), a binder (B), a dispersion resin (C), and a solvent (D), wherein the insulation paste has a viscosity (shear rate of 1 s−1) of 2000 mPa·s or more, and has a TI value of greater than 1, and the TI value is a ratio of the viscosity at a shear rate of 1 s−1 to the viscosity at a shear rate of 1000 s−1.