Segmented Fixing Tape for Battery Electrode Assembly Impregnation
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Solution Overview
Problem
The existing methods for manufacturing nonaqueous electrolyte secondary batteries face challenges in quickly impregnating electrode assemblies with electrolytic solutions, especially when the electrode assembly is highly loaded, leading to potential voltage failures and difficulties in inserting the assembly into battery cases.
Innovation Solution
A nonaqueous electrolyte secondary battery design featuring a rectangular or square fixing tape with self-adhesive portions at both ends of a non-adhesive portion, applied to cover the end of the coil, and a method involving pressurization of the battery case before electrolyte solution pouring to enhance impregnation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode assembly is highly loaded with active materials and separator to increase capacity, then the battery capacity increases, but the impregnation speed of electrolytic solution decreases and voltage failure occurs
Solution Approach 1:
The fixing tape is segmented into adhesive portions and non-adhesive portions. The non-adhesive portions create gaps that allow electrolytic solution to penetrate the electrode assembly more easily, resolving the contradiction between high loading density and impregnation speed.
Solution Approach 2:
The fixing tape has different local properties: adhesive portions provide mechanical fixation while non-adhesive portions provide electrolyte penetration pathways. This local differentiation allows the system to maintain both structural integrity and fast impregnation in highly loaded electrode assemblies.
2Stability of the object's composition
If the end of the coil is fastened tightly with fixing tape to secure the electrode assembly, then the structural stability improves, but the impregnation of electrolytic solution is hindered
Solution Approach 1:
The fixing tape is divided into adhesive and non-adhesive portions along its length. The adhesive portions maintain structural stability by securing the electrode assembly, while the non-adhesive portions create channels for electrolyte penetration, thus resolving the contradiction between stability and impregnation speed.
Solution Approach 2:
Different sections of the fixing tape have different functions: adhesive sections provide mechanical bonding for structural stability, while non-adhesive sections provide fluid penetration pathways. This spatial differentiation of properties simultaneously achieves both stability and fast impregnation.
3Productivity
If a self-adhesive tape is applied to fix the end of the coil with adhesive-free portion covering the end, then the electrode assembly can be impregnated with electrolytic solution, but the outer diameter increases making insertion difficult
Solution Approach 1:
The fixing tape applies adhesive only at the edges (self-adhesive portions) while leaving the central region non-adhesive. This localized adhesive application provides both fixation and electrolyte penetration pathways without requiring excessive tape width, thus avoiding increase in outer diameter while maintaining impregnation ease.
4Productivity
If the battery case is pressurized before pouring electrolytic solution to improve impregnation speed, then the productivity increases, but the electrode assembly may be damaged during insertion
Solution Approach 1:
The fixing tape with non-adhesive portions creates inherent penetration pathways that facilitate electrolyte impregnation without requiring high pressure. This segmentation allows normal pressure insertion, preventing electrode assembly damage while achieving fast impregnation.
Solution Approach 2:
The non-adhesive portions of the fixing tape create localized gaps that serve as electrolyte entry points. This local structural modification enables efficient impregnation at normal pressure, avoiding the need for pressurization that could damage the electrode assembly during insertion.
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 design prevents electrode assembly damage during insertion and improves the ease of electrolyte impregnation, thereby enhancing the productivity of nonaqueous electrolyte secondary batteries by ensuring quicker and more reliable impregnation.
Implementation Method 1
the side of the fixing tape in contact with the electrode assembly includes self-adhesive portions having a pressure-sensitive adhesive
Implementation Method 2
the regions of the fixing tape that are free from the pressure-sensitive adhesive are impregnated with an electrolytic solution quickly
Implementation Method 3
the inside of a battery case accommodating an electrode assembly is pressurized to a prescribed pressure before the pouring of an electrolytic solution
Data Source
AI summary
A nonaqueous electrolyte secondary battery including an electrode assembly the electrode assembly being fastened with a rectangular or square fixing tape applied to cover the end of the coil, the side of the fixing tape in contact with the electrode assembly including self-adhesive portions having a pressure-sensitive adhesive and a non-adhesive portion having no pressure-sensitive adhesive, the self-adhesive portions being disposed at both ends of the non-adhesive portion in the direction of the width of the fixing tape so that the non-adhesive portion is interposed between the self-adhesive portions, the battery satisfying 0.9≤Wb/Wa≤1 and 0.35≤Wc/Wa≤0.8 wherein Wa is the height of the electrode assembly, Wb is the width of the fixing tape and Wc is the width of the non-adhesive portion.