Button Cell Gasket Structure to Prevent Separator Melting
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Solution Overview
Problem
Conventional button cells experience short circuits due to separator melting during the welding process of the case and cap plate, leading to manufacturing challenges and battery capacity deterioration.
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, facilitating easy accommodation of the electrode assembly and minimizing capacity loss during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed between the case and cap plate to secure assembly, then assembly strength is improved, but the separator melts due to welding heat causing short circuit
Solution Approach 1:
An annular gasket is introduced as an intermediary component between the electrode assembly and the welding area. The gasket includes an annular welded portion that is welded to the case and cap plate, while the main body portion extends to contact and protect the electrode assembly, preventing direct exposure to welding heat.
Solution Approach 2:
The gasket is divided into distinct functional segments: an annular welded portion for structural attachment, and a main body portion for electrode protection. The cut portions further segment the gasket structure to enable proper positioning and deformation during assembly, allowing it to conform to the electrode assembly while maintaining protective function.
2Reliability
If an annular gasket is added to protect the electrode assembly from welding heat, then separator protection is improved, but device complexity increases
Solution Approach 1:
The annular gasket serves multiple functions simultaneously: it provides structural support through the welded portion, protects the electrode assembly from welding heat, prevents separator melting, and maintains battery capacity. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The gasket's physical parameters are optimized to balance protection and complexity: the thickness is controlled (1-3mm) to provide adequate heat protection while remaining thin enough to minimize space occupation. The cut portions are strategically designed to enable easy assembly without requiring complex positioning mechanisms.
3Reliability
If the gasket is made continuous to fully protect the electrode assembly, then protection effectiveness is improved, but accommodation difficulty increases due to interference with assembly
Solution Approach 1:
The gasket includes cut portions that divide the continuous structure into segments. These cuts allow the gasket to deform and accommodate the electrode assembly during insertion without creating interference, while still maintaining continuous protection when assembled.
Solution Approach 2:
The gasket transitions from a rigid continuous structure to a dynamic structure with cut portions that can deform during assembly. This allows the gasket to adapt to the electrode assembly's position and shape, facilitating easy accommodation while maintaining protection effectiveness in the final assembled state.
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
The annular gasket effectively prevents short circuits and movement of the electrode assembly, ensuring reliable assembly and maintaining battery capacity by blocking welding heat and supporting the electrode assembly during the manufacturing process.
Implementation Method 1
the annular gasket... suppressing melting of a separator of the electrode assembly due to welding heat welding between a case and a cap plate
Implementation Method 2
an annular gasket positioned inside the case to correspond to the annular welded portion and positioned between the electrode assembly and the edge of the cap plate and between the electrode assembly and a sidewall of the case
Data Source
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AI summary
A button cell includes: an electrode assembly configured to include a first electrode, a second electrode, and a separator; a case connected to the first electrode and configured to accommodate the electrode assembly and to include an opening exposing the electrode assembly;; a cap plate coupled to the case to cover an outer area of the opening and configured to include a through hole exposing a central area of the opening; a terminal plate connected to the second electrode, to be insulatively bonded to the cap plate, and to cover the through hole; an annular welded portion configured to weld between an edge of the cap plate and a sidewall of the case; and an annular gasket positioned inside the case to correspond to the annular welded portion and positioned between the electrode assembly and the edge of the cap plate and between the electrode assembly and a sidewall of the case.