Button Cell Adhesive Joint Design for Sealing and Isolation
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Solution Overview
Problem
Conventional button battery manufacturing methods using preformed elastomer seals face challenges such as limited active volume, complex electrode arrangements, and poor sealing due to compression issues, which restrict the choice of adhesives and increase the risk of contamination by electrolyte.
Innovation Solution
A two-stage assembly process using a glue joint between three parts of the battery casing, where the glue joint is arranged inside the container to ensure compression stress and avoid tension, allowing for the selection of adhesives with higher polymerization temperatures and preventing electrolyte contamination, with the option to weld the third part after filling with active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-formed elastomer gasket is used to seal the battery casing, then galvanic isolation between terminals is provided, but the assembly occupies significant space restricting active volume
Solution Approach 1:
The invention extracts the sealing function from a separate pre-formed elastomer gasket component and integrates it directly into the bonding surface of the casing parts. The bonding surface itself becomes the sealing element, eliminating the need for additional sealing components and thereby increasing active volume while maintaining galvanic isolation.
Solution Approach 2:
The invention merges the structural bonding function with the sealing function into a single integrated bonding surface. The adhesive joint simultaneously provides mechanical bonding between casing parts and galvanic isolation, eliminating the need for separate sealing components.
2Reliability
If a pre-formed elastomer seal is compressed to ensure leak-proof closure, then sealing reliability is improved, but a folding step is required increasing device complexity
Solution Approach 1:
The invention removes the complex folding operation from the manufacturing process by using a bonding surface that provides sealing through adhesive bonding rather than mechanical compression. The sealing function is achieved through the adhesive joint itself, eliminating the need for folding steps.
Solution Approach 2:
The invention replaces the mechanical compression system (folding and compressing elastomer seals) with a chemical bonding system (adhesive bonding). The adhesive provides both structural bonding and sealing functions through chemical adhesion rather than mechanical compression.
3Stability of the object's composition
If adhesive with low polymerization temperature is selected to avoid damaging separator, then separator integrity is maintained, but mechanical and chemical resistance of assembly is reduced
Solution Approach 1:
The invention applies local quality by creating a dedicated bonding surface with specific properties optimized for adhesive bonding. This bonding surface provides the necessary mechanical and chemical resistance locally at the joint, while the separator elsewhere in the battery maintains its integrity through appropriate material selection and placement away from the bonding zone.
Solution Approach 2:
The bonding surface acts as an intermediary between the adhesive and the battery components. It provides a controlled interface that allows the use of adhesives with optimal polymerization temperatures while maintaining overall assembly strength, decoupling the temperature constraint from the strength requirement.
4Reliability
If bonding is performed before filling with active material, then adhesive joint is protected from electrolyte contamination, but manufacturing time is increased
Solution Approach 1:
The invention applies preliminary action by performing the adhesive bonding operation before filling the battery with active material and electrolyte. This sequence prevents electrolyte contamination of the adhesive joint, ensuring long-term reliability. The additional time required is offset by eliminating subsequent contamination control steps and rework.
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 method enhances the mechanical and chemical resistance of the battery assembly, increases the active volume, and simplifies the sealing process by avoiding the need for crimping or edging, while maintaining effective electrical isolation and mechanical strength.
Implementation Method 1
a manufacturing process and a battery according to the attached claims are proposed... the first and second parts are bonded together to form a structure with an adhesive joint between them
Implementation Method 2
A spacer is incorporated into the adhesive joint to ensure a minimum thickness. In one variation, the adhesive joint has a substantially constant thickness, controlled by the spacer
Implementation Method 3
Subsequently, after filling the structure and/or at least the third part with the intended solid active ingredient, the casing is closed by welding the third part to the structure
Data Source
Figure 1a~1c
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a method for manufacturing a battery comprising a casing (1) equipped with a container (2) and a closure portion (3) of this container, this method comprising the following successive steps: - providing at least three parts with a first part (3) defining one pole, as well as a second part (6) and a third part (7) defining the other pole and intended to form the container together, the first and second parts comprising respectively a first surface (3a) and a second surface (6a) of corresponding shape, at least a bonded portion of each of these surfaces extending into a geometric surface not parallel to a general axis (12) of the battery; - bonding the aforementioned first and second surfaces to provide a structure with an adhesive joint (4) between the first and second parts; - welding the third part (7) with the second part;with the adhesive joint positioned against an inner face of the container, the aforementioned bonded portion of the second part forming a stop, along the general axis, for the first part which is located inside the container.