Separator Adhesive Stripe Pattern for Battery Winding
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face issues with adhesive resin causing sticking and electrical charging during manufacturing, inhibiting gas release and impregnation of electrolyte, leading to reduced handleability and battery resistance.
Innovation Solution
A separator with a porous resin base material and a ceramic layer containing 85% or more inorganic particles, along with an adhesive layer having 3-65% inorganic particles and a specific angle, forming a stripe pattern to enhance antistatic and degassing properties and improve electrolyte impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive resin is disposed on the surface of separator to enhance adhesion, then adhesion between electrode and separator is improved, but the adhesive resin becomes electrically charged causing sticking and manufacturing defects
Solution Approach 1:
The adhesive layer is configured with a stripe pattern rather than continuous coverage, creating regions with different properties. The adhesive resin is localized to specific stripes with controlled width and spacing, reducing overall electrical charging while maintaining adhesion in critical areas. This local quality approach allows the separator to have both adhesive regions and non-adhesive regions in a systematic pattern.
Solution Approach 2:
The invention changes the parameters of the adhesive layer including its content (3-65 mass%), width (0.5-4 mm), coverage (50-90%), and orientation angle (20-70 degrees). By optimizing these parameters, the adhesive layer provides sufficient adhesion while minimizing electrical charging effects. The specific parameter ranges balance adhesion performance with antistatic properties.
2Strength
If adhesive resin is disposed on separator surface, then adhesion is enhanced, but gas release is inhibited during winding
Solution Approach 1:
The stripe pattern creates local variations in adhesive coverage, allowing gas to escape through non-adhesive regions between the stripes. The gaps between adhesive stripes serve as gas release channels during the winding process, while the adhesive stripes themselves provide localized bonding. This spatial differentiation resolves the contradiction between adhesion and gas release.
3Strength
If adhesive resin is disposed on separator surface, then adhesion is enhanced, but porosity of separator decreases reducing electrolyte impregnating ability
Solution Approach 1:
The adhesive layer is applied in stripes rather than continuously, creating a pattern where adhesive regions provide bonding and non-adhesive regions maintain porosity for electrolyte penetration. This localized application preserves the separator's overall porosity and electrolyte impregnating ability while providing sufficient adhesion at the adhesive stripe locations.
Solution Approach 2:
The stripe pattern creates a replicated structure across the separator surface, with alternating adhesive and non-adhesive regions. This periodic pattern ensures uniform adhesion distribution while maintaining consistent porosity and electrolyte flow paths throughout the separator, balancing adhesion and impregnation requirements.
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 separator achieves high antistatic and degassing properties, facilitating smooth winding and high electrolyte impregnation, thereby reducing battery resistance and enhancing production efficiency.
Implementation Method 1
the adhesive layer includes an adhesive resin and second inorganic particles... A content of the second inorganic particles in the adhesive layer is 3 mass % or more and 65 mass % or less. An angle formed by the adhesive layer and the long side of the at least one principal surface of the separator is 20° or more and 70° or less... This configuration can provide the separator with high antistatic property
Implementation Method 2
high degassing property in winding... It has been also found that gas (air) release is inhibited in winding a separator, resulting in problems such as difficulty in smooth winding and a decrease in handleability of a winding body
Implementation Method 3
a base material layer of a porous resin... in bonding a separator and an electrode to form an electrode body, porosity of the separator decreases to reduce impregnating ability of the nonaqueous electrolyte
Data Source
AI summary
The separator disclosed here includes a base material layer of a porous resin, and a ceramic layer containing 85 mass % or more of first inorganic particles and disposed on at least one surface of the base material layer. Principal surfaces of the separator have long sides. The separator further includes an adhesive layer having portions arranged at a predetermined pitch to form a stripe pattern on at least one of the principal surfaces. The adhesive layer contains an adhesive resin and second inorganic particles. A content of the second inorganic particles in the adhesive layer is 3 mass % or more and 65 mass % or less. An angle formed by the adhesive layer and the long side of the at least one principal surface of the separator is 20° or more and 70° or less.