Button Cell Gasket Structure for Welding Heat Isolation
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Solution Overview
Problem
Conventional button cells face issues with separator melting due to welding heat during manufacturing, leading to short circuits, and existing solutions fail to effectively prevent this while accommodating the electrode assembly and maintaining battery capacity.
Innovation Solution
Incorporating an annular gasket with cut portions between the electrode assembly and the case and cap plate, which suppresses movement and melting of the separator, and includes an insulating washer to further prevent short circuits and battery capacity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case and cap plate are welded together during manufacturing, then the structural integrity and sealing of the button cell is improved, but the separator of the electrode assembly may be melted by the welding heat, causing a short circuit between opposite electrodes
Solution Approach 1:
An insulating gasket is introduced as an intermediary component positioned between the electrode assembly and the case/cap plate welding area. This gasket serves as a thermal barrier that protects the separator from welding heat while allowing the case and cap plate to be securely welded together, thus resolving the contradiction between structural integrity and separator protection
2Reliability
If an annular gasket is added to protect the separator from welding heat, then the reliability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The annular gasket is designed to perform multiple functions simultaneously: it acts as a thermal barrier protecting the separator from welding heat, provides electrical insulation between the electrode assembly and the case/cap plate, and serves as a mechanical support structure. By consolidating these functions into a single component, the design minimizes added complexity while achieving reliable separator protection
3Reliability
If the annular gasket is positioned close to the electrode assembly to protect it, then the separator protection is improved, but the ease of accommodating the electrode assembly during manufacturing deteriorates
Solution Approach 1:
The annular gasket is designed with flexible properties that allow it to dynamically adapt during the electrode assembly installation process. The gasket can be temporarily deformed or compressed to accommodate the electrode assembly, and then returns to its protective position once the assembly is in place, thus enabling easy manufacturing while maintaining separator protection
Data Source
AI summary
A button cell includes: an electrode assembly including first and second electrodes and a separator therebetween; a case accommodating the electrode assembly, electrically connected to the first electrode, and having an opening exposing the electrode assembly; a cap plate coupled to at an outer periphery of the opening in the case and having a through hole exposing a central area of the opening; a terminal plate connected to the second electrode, insulatively bonded to the cap plate, and covering the through hole; an annular welded portion connecting an edge of the cap plate and a sidewall of the case; and an annular gasket inside the case along the annular welded portion and between the electrode assembly, the edge of the cap plate, and a sidewall of the case. The annular gasket has a plurality of cut portions spaced apart from each other along an inner edge thereof.