Battery Cap Assembly Sealing Structure for Thin High-Capacity Cells
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Solution Overview
Problem
Existing secondary battery cap assemblies are prone to deformation during cell forming, compromising airtightness and capacity while being difficult to make durable.
Innovation Solution
A cap assembly design where the circumferential portion of the cap-up is half-curled downward toward a safety plate, combined with an insulation gasket that fills a gap between the cap-up and the safety plate, improving airtightness and maintaining a relatively large capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cap assembly is made thinner to increase cell capacity and energy density, then the cell capacity and energy density are improved, but the cap assembly becomes more easily deformed by force applied during cell forming
Solution Approach 1:
The cap-up's circumferential portion is designed with a curved shape that curls downward toward the safety plate, creating a half-curved structure. This curvature provides structural reinforcement against deformation during cell forming while maintaining a thin overall profile, thus resolving the contradiction between thinness for capacity and strength for deformation resistance
Solution Approach 2:
The cap assembly combines multiple materials including the cap-up, safety plate, and insulation gasket with different mechanical properties. This composite structure allows the thin cap assembly to achieve both the required thickness reduction for capacity and sufficient strength through material combination and structural design
2Quantity of substance
If the cap assembly is made thinner to increase energy density, then the energy density is improved, but the airtightness of the cap assembly deteriorates
Solution Approach 1:
The curved, half-curved structure of the cap-up's circumferential portion creates a tighter fit with the safety plate, improving the sealing interface. This curvature design maintains airtightness despite the reduced overall thickness of the cap assembly, resolving the contradiction between thinness for energy density and sealing quality for airtightness
Solution Approach 2:
The insulation gasket acts as an intermediary sealing element between the cap-up and safety plate. It fills the gap between these components to ensure airtightness, allowing the cap assembly to maintain sealing performance even with reduced thickness that increases energy density
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 design enhances airtightness and maintains a high capacity by reducing the overall thickness of the cap assembly while ensuring durability against forces applied during cell forming.
Implementation Method 1
the gap filling portion may be formed by melting a part of the insulation gasket
Data Source
AI summary
A secondary battery includes a cylindrical can, an electrode assembly in the cylindrical can together with an electrolytic solution, and a cap assembly coupled to the top of the cylindrical can, the cap assembly including a cap-up, a safety plate coupled to a lower surface of the cap-up, and an insulation gasket wrapping the cap-up and the safety plate, the insulation gasket filling a gap filling portion between the cap-up and the safety plate.