Battery Case-Cap Sealing Structure for Electrolyte Leak Prevention
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Solution Overview
Problem
Existing secondary batteries face challenges in maintaining effective sealing performance of the cell housing, which can lead to electrolyte leakage and potential short circuits.
Innovation Solution
The secondary battery design incorporates a case with a beading portion and crimping portion, featuring specific curvature and strain calculations, along with a gasket system to enhance sealing and insulation between the case and cap plate, ensuring secure fixation and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing structure is used between case and cap plate, then the structure is simple, but sealing performance deteriorates leading to electrolyte leakage
Solution Approach 1:
The sealing structure is divided into multiple functional segments: the gasket provides primary sealing, the crimping portion provides mechanical fixation and secondary sealing, and the beading portion provides structural support. This segmentation allows each component to specialize in its function, improving overall sealing performance while keeping individual components relatively simple.
Solution Approach 2:
The sealing system uses composite construction combining the gasket material (likely rubber or polymer) with the metal case and cap plate structures. This composite approach allows the gasket to provide flexible sealing while the metal structures provide rigid mechanical support and fixation, achieving reliable sealing without excessive complexity in any single component.
2Strength
If the crimping portion is bent more to fix the cap plate securely, then fixation strength improves, but the forming curvature increases making manufacturing more difficult
Solution Approach 1:
The patent optimizes the crimping portion geometry by adjusting parameters such as the bending angle, crimping depth, and profile shape to achieve adequate fixation strength while keeping the forming curvature within manufacturable limits. This parameter optimization allows the crimping portion to provide secure fixation without requiring excessively complex forming operations.
3Reliability
If the beading portion is depressed deeper to improve sealing support, then support strain increases improving sealing, but the depression depth increases making manufacturing more difficult
Solution Approach 1:
The beading portion geometry is optimized by adjusting parameters such as depression depth, diameter, and profile shape to provide adequate sealing support while keeping the deformation within manufacturable limits. This parameter optimization ensures the beading portion provides necessary structural support for sealing without requiring excessively deep or complex forming operations.
Data Source
AI summary
Disclosed is a secondary battery capable of improving sealing performance of a cell housing part including a case and a cap plate. The secondary battery includes an electrode assembly, including first and second electrode plates and a separator, a case accommodating the electrode assembly and electrically connected to the second electrode plate, a terminal mounted to the case configured to be electrically connected to the first electrode plate, a cap plate sealing an open top of the case, and a second gasket interposed between the case and the cap plate. The case includes a beading portion depressed inward and a crimping portion bent inward. A forming curvature calculated based on a bending amount of the crimping portion and a covering length of the crimping portion is different from a support strain calculated based on a depression depth of the beading portion and a cover overlapping length of the crimping portion.