Button Cell Vent Plate Structure for Pressure Relief
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Solution Overview
Problem
Conventional button cells are prone to explosion due to increased internal pressure caused by gas generation from short circuits in the electrode assembly.
Innovation Solution
A button cell design featuring a terminal plate with a vent portion recessed from its rear surface, allowing gas to be discharged through a through-hole, preventing pressure buildup and potential explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the case is sealed to protect the electrode assembly, then the reliability is improved, but gas accumulation causes pressure increase leading to explosion
Solution Approach 1:
A vent portion is introduced as an intermediary component between the sealed case interior and exterior. This vent portion allows controlled gas discharge while maintaining the sealed structure's protective function, resolving the contradiction between sealing reliability and pressure safety.
Solution Approach 2:
The vent portion functions as a porous or permeable structure within the terminal plate, enabling selective gas passage while maintaining structural integrity. This allows the case to remain sealed against contaminants while permitting pressure relief through the vent portion.
2Object-affected harmful factors
If a vent hole is created in the cap plate to discharge gas, then gas discharge capability is improved, but the structural integrity and sealing are compromised
Solution Approach 1:
Instead of creating a hole through the cap plate thickness, the vent portion is formed by recessing the terminal plate in a planar direction. This dimensional change allows gas discharge functionality without compromising the cap plate's vertical sealing structure.
Solution Approach 2:
The vent portion acts as an intermediary structure that provides gas discharge capability while being integrated into the terminal plate rather than creating an opening in the cap plate. This maintains the cap plate's structural integrity and sealing function.
3Strength
If the terminal plate is made thicker to improve structural strength, then the strength is improved, but gas discharge efficiency through the vent portion decreases
Solution Approach 1:
The terminal plate is segmented into different thickness regions: a thicker main body for structural strength and a thinner vent portion for gas discharge efficiency. This segmentation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The terminal plate exhibits local quality variation where the vent portion has reduced thickness specifically at the gas discharge location, while the rest of the terminal plate maintains sufficient thickness for structural strength. This localized thinning optimizes gas discharge without compromising overall structural integrity.
Data Source
AI summary
A button cell includes: an electrode assembly that includes a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a case that is connected to the first electrode to accommodate the electrode assembly and includes an opening exposing the electrode assembly; a cap plate that is coupled to the case to cover an outer region of the opening and includes a through-hole exposing a central region of the opening; and a terminal plate that is connected to the second electrode to be insulated from the cap plate and covers the through-hole. The terminal plate includes a vent portion recessed from a rear surface of the terminal plate facing the through-hole.