Battery Pouch Inner Layer Chemistry for Electrolyte Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pouch-type lithium secondary batteries face issues with internal short circuits due to external impacts and have low high-temperature safety and storage properties, primarily because the pouch exterior material lacks sufficient adhesion with the gel polymer electrolyte, leading to mechanical performance deterioration and potential explosions.
Innovation Solution
Incorporating an inner layer with ethylenically unsaturated groups in the pouch exterior material that participate in radical polymerization with oligomers in the gel polymer electrolyte, enhancing adhesion and mechanical performance, and using a multi-layered structure with a metal barrier layer for improved safety and storage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pouch exterior material with multi-layered film structure is used, then the battery can be manufactured in various forms with smaller volume and mass, but the adhesion with gel polymer electrolyte is insufficient leading to internal short circuits and low high-temperature safety
Solution Approach 1:
The invention changes the chemical composition parameters of the inner layer by incorporating ethylenically unsaturated groups (vinyl, acryloxy, or methacryloxy groups) into the resin. This chemical modification enables radical polymerization reactions with the gel polymer electrolyte, transforming the adhesion mechanism from physical bonding to chemical bonding, thereby resolving the adhesion insufficiency without complicating the overall pouch structure
Solution Approach 2:
The invention creates a composite material system where the inner layer combines resin with ethylenically unsaturated groups and the gel polymer electrolyte forms an integrated structure through radical polymerization. This composite approach establishes strong chemical bonds between the pouch exterior material and electrolyte, preventing internal short circuits while maintaining the simplicity of the pouch-type battery structure
2Reliability
If gas is generated inside the battery due to oxidation decomposition reaction of electrolyte under high temperatures, then the battery volume expands, but without sufficient adhesion the gas is not controlled leading to low high-temperature safety and storage properties
Solution Approach 1:
The invention modifies the thermal stability parameters by establishing strong chemical bonds through radical polymerization between the pouch exterior material and gel polymer electrolyte. This chemical bonding prevents electrolyte oxidation decomposition at high temperatures, controlling gas generation and maintaining battery integrity under thermal stress, thereby improving high-temperature safety and storage properties
Solution Approach 2:
The invention applies preliminary protective action by pre-establishing strong adhesion bonds before high-temperature conditions occur. The radical polymerization creates a robust interface that prevents oxidation decomposition reactions before they can generate harmful gases, proactively addressing high-temperature safety issues rather than reacting to them after failure occurs
3Ease of manufacture
If the pouch exterior material lacks sufficient adhesion with gel polymer electrolyte, then the battery can be manufactured more simply, but mechanical performance deteriorates and internal short circuits occur due to external impacts
Solution Approach 1:
The invention changes the bonding mechanism parameter from physical adhesion to chemical bonding through radical polymerization. The ethylenically unsaturated groups in the inner layer react chemically with the gel polymer electrolyte, creating strong covalent bonds that significantly enhance mechanical performance and resistance to external impacts while maintaining ease of manufacture through a single-layer modified structure
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 improved adhesion between the pouch exterior material and gel polymer electrolyte enhances mechanical stiffness, prevents internal short circuits, and suppresses battery swelling and ignition during high-temperature conditions, thereby improving safety and storage properties.
Implementation Method 1
an inner layer which contains an ethylenically unsaturated group, wherein the ethylenically unsaturated group is coupled with the oligomer
Data Source
AI summary
The present invention relates to a pouch exterior material which is for a lithium secondary battery and includes an inner layer, an outer resin layer, and a metal layer located between the inner layer and the outer resin layer, wherein the inner layer contains an ethylenically unsaturated group, and a lithium secondary battery including the pouch exterior material.