Button Cell Adhesive Joint for Volume and Sealing
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Solution Overview
Problem
The existing button cell housing design with an elastomer seal is inefficient, as it occupies a significant portion of the volume, reducing the space available for active material, and the adhesive joint is prone to stress and contamination, affecting its adhesion and tightness.
Innovation Solution
A method of manufacturing a button cell with an adhesive joint arranged to work under compression, where the adhesive layer is applied on an inclined edge area of the lid, inserted into the cup, and cured to form a mechanical stop, ensuring sealing and insulation, while minimizing stress and contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomer seal is used between cup and lid, then sealing reliability is improved, but internal volume available for active material is reduced
Solution Approach 1:
The patent removes the elastomer seal component from the cell housing structure and replaces it with an adhesive joint system. This extraction of the separate sealing component eliminates the volume occupied by the seal while maintaining sealing functionality through the adhesive layer applied to the cup edge.
Solution Approach 2:
The patent combines the sealing function and the structural joining function into a single adhesive joint. The adhesive serves dual purposes: it seals the gap between cup and lid while also providing mechanical attachment, eliminating the need for separate seal components and reducing overall housing volume.
2Volume of moving object
If adhesive joint is used instead of elastomer seal, then internal volume is increased, but adhesion reliability is worsened due to stress and contamination
Solution Approach 1:
The patent applies adhesive specifically to the edge region of the cup with controlled thickness and distribution. By localizing the adhesive application to the critical sealing zone at the cup edge, the design ensures adequate adhesion and sealing where needed while minimizing overall material usage and maintaining volume efficiency.
Solution Approach 2:
The patent incorporates preliminary protective measures during manufacturing, including applying adhesive before inserting the lid and using fixtures to maintain proper positioning during curing. These preliminary actions ensure optimal adhesion conditions are established before stress or contamination can affect the joint.
3Ease of manufacture
If adhesive layer is applied on vertical edge area, then manufacturing is simplified, but adhesion is impaired under overpressure conditions
Solution Approach 1:
The patent transitions from a symmetric vertical adhesive application to an asymmetric angled application. The adhesive is applied at a specific angle (e.g., 45 degrees) relative to the cup axis, creating an asymmetric joint configuration that optimizes stress distribution under overpressure conditions while maintaining manufacturing feasibility through controlled application processes.
Solution Approach 2:
The patent changes the geometric parameter of the adhesive application from vertical (90 degrees to axis) to an angled configuration (e.g., 45 degrees). This parameter change in the adhesive layer orientation fundamentally alters the stress distribution mechanics, transforming tensile and shear stresses into compressive stresses that enhance adhesion reliability under overpressure.
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 design increases the internal volume of the cell by about 10%, enhancing energy density and capacity, while maintaining tightness and simplifying the assembly process by eliminating the need for a pre-formed seal and reducing stress on the adhesive joint during overpressure.
Implementation Method 1
applying a layer of adhesive on an edge area of the first part... curing said layer of adhesive to form an adhesive joint sealing the housing and electrically insulating the two poles
Data Source
AI summary
A cell, in particular a button cell, and to a method for manufacturing such a cell, the method includes providing a first part and a second part intended to respectively form the lid and the cup of the housing, the first part including an edge area with a zone inclined or perpendicular with respect to a center axis of the housing; applying a layer of adhesive on the edge area of the first part; then inserting the first part into an open end of the second part, the layer of adhesive on the edge area being finally turned towards the open end of the second part; closing the housing by bending an upper portion of the side wall on the zone of the edge area provided with the layer of adhesive, and curing the layer of adhesive to form an adhesive joint sealing the housing.