Adhesive Layer Separator for Non-Aqueous Battery Heat Resistance
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Solution Overview
Problem
Lithium ion secondary batteries with adhesive layers between separators and electrodes exhibit excellent adhesion but poor heat shrinkage resistance, leading to potential short circuits when the separator shrinks due to increased temperature.
Innovation Solution
Incorporating an adhesive layer on the separator surfaces facing the electrodes, composed of inorganic particles and an organic binder, with a specific peeling strength ratio to prevent direct contact between electrodes and enhance heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive layer is formed on the separator to improve adhesion between the separator and electrode, then adhesion is excellent, but heat shrinkage resistance is low causing potential short circuits
Solution Approach 1:
The adhesive layer is formulated as a composite material containing inorganic particles (such as aluminum oxide, aluminum hydroxide, or magnesium hydroxide) dispersed in an organic binder resin. This composite structure provides both strong adhesion through the organic binder and heat resistance through the inorganic particles, which maintain structural integrity at elevated temperatures and prevent separator shrinkage that would cause short circuits.
2Strength
If the adhesive layer has strong bonding to the separator, then adhesion is excellent, but the adhesive layer may peel off from the electrode at high temperatures
Solution Approach 1:
The invention optimizes the composition parameters of the adhesive layer, specifically controlling the types and amounts of inorganic particles and organic binders. The inorganic particles (e.g., aluminum oxide, aluminum hydroxide) provide thermal stability and maintain adhesion at elevated temperatures, while the organic binder ensures proper bonding. This parameter optimization allows the adhesive layer to maintain both strong bonding and thermal stability, preventing peeling off from the electrode during temperature increases.
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 solution effectively prevents short circuits by maintaining the adhesive layer on the negative electrode surface during temperature increases, thereby improving the safety and cycle characteristics of the battery.
Implementation Method 1
when the temperature of the battery is increased to shrink the separator
Implementation Method 2
an adhesive layer is formed on the second surface or each of the first surface and the second surface, the adhesive layer includes inorganic particles and an organic binder
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, wherein the separator includes a first surface facing the positive electrode and a second surface facing the negative electrode, an adhesive layer is formed on the second surface or each of the first surface and the second surface, the adhesive layer includes inorganic particles and an organic binder, and a ratio of a peeling strength between the separator and the adhesive layer to a peeling strength between the negative electrode and the adhesive layer is more than 0 and 4.0 or less.