Polyolefin Adhesive Composition for Battery Packaging Lamination
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Solution Overview
Problem
Existing packaging materials for lithium-ion batteries face challenges with electrolyte solution resistance and moldability, including issues with pot life properties, thermal shrinkage of polyolefin substrates, and adhesion, which affect the lamination strength and lead to potential leakage and corrosion.
Innovation Solution
An adhesive composition comprising acid-modified polyolefin, a curing agent, and a specific blend of organic solvents, which provides excellent re-solubility, adhesion, and chemical resistance, allowing for effective bonding between polyolefin and metal substrates at lower temperatures and maintaining stability during production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a curing agent is blended to improve adhesion and chemical resistance, then bonding strength and electrolyte solution resistance are improved, but pot life properties deteriorate and the adhesive solidifies too quickly
Solution Approach 1:
The patent changes the chemical parameters of the curing agent system by selecting specific epoxy resins with controlled reactivity and using precise ratios of hardener to epoxy (0.8-1.2:1). This parameter optimization allows the adhesive to maintain adequate pot life while achieving the required bonding strength and chemical resistance after curing.
Solution Approach 2:
The patent introduces a latent catalyst system as an intermediary between the epoxy resin and hardener. The latent catalyst remains inactive during storage and application, preventing premature curing, but activates under specific conditions (heat or moisture) to enable complete curing and achieve maximum bonding strength and chemical resistance.
2Strength
If bonding is performed at high temperature to improve adhesion, then bonding strength is improved, but thermal shrinkage of polyolefin substrate increases causing deformation
Solution Approach 1:
The patent changes the temperature parameter of the bonding process by using a low-temperature curing adhesive system that achieves full adhesion strength at temperatures below the polyolefin substrate's melting point, thereby preventing thermal shrinkage and substrate deformation while maintaining strong bonding.
Solution Approach 2:
The patent replaces the conventional thermal bonding mechanism with a chemical bonding mechanism. Instead of relying on heat-induced melting and fusion, the adhesive uses chemical reactions (epoxy-hardener crosslinking) to create strong bonds at lower temperatures, eliminating the harmful thermal effects on the substrate.
3Productivity
If adhesive composition is applied to gravure roll for coating, then coating efficiency is improved, but adhering matter accumulates and clogs the roll
Solution Approach 1:
The patent introduces a re-solvent as an intermediary substance that can redissolve the cured adhesive on the gravure roll surface. The re-solvent periodically removes accumulated adhering matter, preventing clogging and maintaining continuous high-efficiency coating operations without interrupting the production process.
Solution Approach 2:
The patent implements a system where the re-solvent discards the accumulated adhering matter from the gravure roll and recovers it as a separate waste stream. This prevents the adhering matter from interfering with the coating process while allowing the main adhesive system to continue operating at high productivity.
4Reliability
If electrolyte solution resistance is improved by material selection, then chemical resistance is improved, but adhesion to substrates deteriorates
Solution Approach 1:
The patent creates a composite adhesive system combining epoxy resin (providing chemical resistance to electrolyte solutions) with polyolefin components (providing adhesion to polyolefin substrates). This composite formulation achieves both electrolyte solution resistance and strong adhesion simultaneously by integrating the beneficial properties of different material systems.
Solution Approach 2:
The patent applies local quality by designing the adhesive to have different functional regions: the epoxy-hardener system provides chemical resistance in contact with electrolyte solutions, while the polyolefin components and surface-active agents provide adhesion to the polyolefin substrate. Each component performs its specialized function in the appropriate location within the adhesive system.
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 adhesive composition ensures strong adhesion and chemical resistance, preventing electrolyte leakage and corrosion, while maintaining re-solubility to prevent clogging and allowing for efficient production processes, even at lower temperatures.
Implementation Method 1
an adhesive composition comprising an acid-modified polyolefin (A), a curing agent (B), and an organic solvent (C)
Implementation Method 2
an adhesive composition comprising an acid-modified polyolefin (A), a curing agent (B), and an organic solvent (C)
Data Source
AI summary
Provided is an adhesive composition having excellent re-solubility, excellent adhesion, and excellent chemical resistance (electrolyte solution resistance), and a packaging material for batteries, the packaging material comprising an adhesive layer of the adhesive composition, as well as a battery that uses the packaging material. The adhesive composition comprises an acid-modified polyolefin (A), a curing agent (B), and an organic solvent (C), wherein the total amount of adhering matter of the acid-modified polyolefin (A), the curing agent (B), and a reaction product thereof after a re-dissolution test is 200 g/m2 or less.