Button Battery Gasket Sealing via Silicatised Layer
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Solution Overview
Problem
Button batteries face premature aging due to moisture ingress through the interface between the polymer gasket and the battery case, despite existing solutions failing to provide a satisfactory and cost-effective sealing method, as the adhesion between the adhesive and the gasket is inadequate, particularly with polymers like polypropylene that have low surface energies.
Innovation Solution
The method involves tribochemical sand blasting to increase the surface energy of the gasket, followed by the deposition of a silicatised layer and an adhesion promoter, creating a strong and lasting chemical bond between the gasket and the adhesive, enhancing the sealing properties of the battery without requiring expensive equipment or short-lasting treatments like corona or plasma treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is applied to bond the polymer gasket to the case, then sealing is improved, but adhesion is insufficient due to low surface energy of polymers like polypropylene
Solution Approach 1:
The invention changes the surface energy parameter of the polymer gasket by treating it with a silane-based primer. This treatment modifies the chemical composition and surface properties of the polymer, transforming it from a low surface energy material that resists adhesion to a high surface energy material that promotes strong bonding with the adhesive layer, thereby resolving the adhesion insufficiency while maintaining sealing quality
Solution Approach 2:
The silane-based primer acts as an intermediary layer between the polymer gasket and the adhesive. This primer contains silane groups that bond to the polymer surface and functional groups that bond to the adhesive, creating a chemical bridge that ensures strong adhesion. The primer mediates the interface between the two materials, allowing effective stress transfer and preventing delamination
2Strength
If plasma or corona treatment is used to increase surface energy, then adhesion is improved, but the treatment is expensive and short-lasting
Solution Approach 1:
The invention replaces expensive, complex plasma or corona treatment equipment with a simple, inexpensive silane-based primer application process. The primer can be applied using conventional coating methods, eliminating the need for expensive vacuum chambers or specialized plasma generators. This makes the adhesion enhancement process economically viable and easier to manufacture
Solution Approach 2:
Instead of using high-energy plasma or corona discharge to temporarily modify surface properties, the invention uses a chemical primer treatment that creates permanent chemical bonds. The silane-based primer undergoes hydrolysis and condensation reactions to form stable covalent bonds with the polymer surface, providing lasting adhesion improvement without the time constraints of plasma treatment
3Strength
If plasma or corona treatment is applied, then wettability is improved, but the effect is lost after venting or over time
Solution Approach 1:
The silane-based primer treatment creates continuous, stable chemical bonds between the polymer gasket and the adhesive layer. Unlike plasma or corona treatment that temporarily increases surface energy, the primer forms a permanent chemical modification that maintains its adhesion-promoting properties throughout the service life of the battery, ensuring continuous useful action without degradation over time
Solution Approach 2:
The invention creates a composite structure consisting of the polymer gasket, silane-based primer layer, and adhesive layer. The silane primer forms a chemically bonded interface between the polymer and adhesive, creating a multi-layer composite system with enhanced interfacial strength. This composite approach ensures long-lasting adhesion by distributing stresses across multiple bonded interfaces
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 approach results in improved sealing and extended battery life, with enhanced wettability and adhesion properties that persist for over a month, reducing internal resistance by about 25% after aging, compared to standard batteries.
Implementation Method 1
implanting, by tribochemical sand blasting on at least one part of the surface of the gasket, a silicatised layer
Implementation Method 2
The adhesion promoter comprises silanes which form a chemical bond with the silicatised layer, and other chemical functions selected depending on the adhesive in order to specifically react with the adhesive deposited
Data Source
AI summary
A method of manufacturing a battery, in particular a button battery, including a case, provided with a container and a cap, and a polymer gasket, in particular made of polypropylene, compressed and bonded between the container and the cap. The method successively includes a step of implanting a silicatised layer by tribochemical sand blasting on all or part of the surface of the gasket, a step of adding a layer of adhesive to the surface of the gasket including the silicatised layer and/or on all or part of the surface of the container and of the surface of the cap intended to be joined to the gasket, a step of assembling the case with the gasket positioned by compression and bonding with the layer of adhesive between the container and the cap.