Button Cell Can Coupling Structure for Pressure Venting
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Solution Overview
Problem
Button-type secondary batteries face issues with disassembly and harmful gas leakage due to excessive internal pressure, particularly during overcurrent or high pressure situations, lacking effective mechanisms to collect and contain generated gases.
Innovation Solution
A button-type secondary battery design featuring a larger diameter than height, with a beading part and bent upper end on the lower can, coupled by an insulator, and a vent unit with a rupture notch to manage internal pressure and block current flow, incorporating collection spaces and a porous center pin to secure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the upper can and lower can are press-fitted together to maintain battery shape, then the structural integrity is improved, but the cans are separated when excessive internal pressure is generated
Solution Approach 1:
The lower can is divided into multiple sections: a body portion, an upper portion with a bent shape, and a beading part recessed inward. This segmentation allows the upper portion to provide mechanical interlocking with the upper can while the beading part provides additional frictional engagement, preventing separation under internal pressure.
Solution Approach 2:
The upper portion of the lower can is designed with a bent shape that curves inward, creating a non-linear geometric feature. This curvature allows the upper can to be inserted and locked in place, providing resistance against separation forces generated by internal pressure while maintaining structural integrity.
2Volume of moving object
If the upper can and lower can are press-fitted together with no available space, then the compactness is improved, but there is no space to collect generated gas
Solution Approach 1:
The bent upper portion of the lower can creates a nested space between itself and the upper can. This nested configuration allows gas collection space to be formed within the existing battery structure without increasing the overall external dimensions, maintaining compactness while providing gas accumulation capacity.
Solution Approach 2:
The beading part recessed inward on the lower can creates a radial dimension for gas collection space. By utilizing the radial space between the beading part and the upper can, the design accommodates gas volume without compromising the axial compactness of the battery.
3Object-generated harmful factors
If the cans are separated by internal pressure, then the gas can be released, but the battery cannot function and harmful gas may leak
Solution Approach 1:
The bent upper portion acts as an intermediary structure between the internal gas pressure and the external environment. It provides a controlled interface that allows gas to be contained in the collection space while preventing uncontrolled separation of the cans, thus maintaining battery functionality while managing gas release.
Solution Approach 2:
The beading part recessed inward provides pre-established frictional engagement that cushions against the separating force of internal pressure. This prior cushioning mechanism prevents complete separation of the cans, ensuring that gas is contained rather than released, and maintaining battery functionality under pressure conditions.
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 effectively collects and contains gases within the battery, preventing disassembly and leakage, ensuring safety by blocking current flow and maintaining structural integrity under excessive pressure.
Implementation Method 1
it is the principle that a shape of the button-type secondary battery is maintained due to friction force due to the press-fitting
Implementation Method 2
the upper end of the lower can disposed above the beading part has a bent shape and configured to surround an edge end of the upper can
Data Source
AI summary
A button-type secondary battery includes an electrode assembly; a lower can into which the electrode assembly is disposed; and an upper can configured to cover an opening of an upper end of the lower can. A beading part recessed inward is disposed at an upper portion of the lower can. The upper end of the lower can disposed above the beading part has a bent shape and configured to surround an edge end of the upper can so that the upper can and the lower can are coupled to each other.