Button Cell Sealing Structure to Prevent Separator Heat Damage
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Solution Overview
Problem
Conventional button cells face issues during manufacturing where the welding heat can melt the separator, causing a short circuit between the electrodes, which damages the electrode assembly and affects battery performance.
Innovation Solution
The button cell design incorporates an insulating pouch that thermally fuses to the plates, sealing the electrode assembly without welding, thereby preventing damage from heat and maximizing internal space for improved battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case and cap plate are welded together during manufacturing, then the structural strength and sealing are improved, but the separator may be melted by welding heat causing short circuit
Solution Approach 1:
An insulating pouch made of heat-resistant material is introduced as an intermediary component between the electrode assembly and the case/cap plate. This pouch acts as a thermal barrier that protects the separator from welding heat while maintaining structural integrity and sealing during the welding process.
Solution Approach 2:
The insulating pouch is pre-installed around the electrode assembly before the welding process begins. This preliminary protective measure ensures that when welding occurs, the heat is already blocked from reaching the separator, preventing short circuits before they can happen.
2Ease of manufacture
If a conventional case and cap plate structure is used, then the manufacturing process is simple, but the internal space is reduced limiting battery capacity
Solution Approach 1:
The insulating pouch is designed as a thin-film flexible structure that conforms to the electrode assembly without adding significant volume. This allows maximum internal space utilization for active materials while maintaining ease of manufacturing through a straightforward assembly process.
3Device complexity
If the separator is exposed to welding heat, then the manufacturing process can be simplified, but the separator melts causing short circuit between electrodes
Solution Approach 1:
The insulating pouch serves as a protective intermediary that shields the separator from welding heat. This simple addition maintains manufacturing process simplicity while dramatically improving reliability by preventing separator melting and subsequent short circuits.
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 enhances battery capacity by preventing electrode assembly damage from welding heat and ensuring reliable operation in wearable devices.
Implementation Method 1
an insulating pouch at a side portion of the electrode assembly. The insulating pouch seals the electrode assembly with the first plate and the second plate and has a first fused portion overlapping in a vertical direction and thermally fused to an edge of a lower surface of the first plate and a second fused portion overlapping in the vertical direction and thermally fused to an edge of an upper surface of the second plate
Data Source
AI summary
A button cell includes: an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; a first plate below the electrode assembly and connected to the first electrode; a second plate above the electrode assembly and connected to the second electrode; and an insulating pouch at a side portion of the electrode assembly. The insulating pouch seals the electrode assembly with the first plate and the second plate and has a first fused portion overlapping in a vertical direction and thermally fused to an edge of a lower surface of the first plate and a second fused portion overlapping in the vertical direction and thermally fused to an edge of an upper surface of the second plate.