Button Cell Double-Walled Casing Overpressure Relief
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Solution Overview
Problem
Lithium-ion button cells face safety risks due to overcharging, which can lead to severe gassing, heating, and potential explosive combustion, and existing safety measures like bursting membranes and fuse links are either ineffective or costly.
Innovation Solution
A button cell design featuring a cell cup and cell cover with a circumferential double-walled casing area and a seal, where the cell cover is inserted with a cut edge to form an interlocking connection, and at least one hole that acts as a safety valve to dissipate overpressure, preventing the cell cover from being peened over and ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bursting membranes are added to ensure operational safety, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the safety function from separate components (bursting membranes, fuse links) and integrates it into the basic housing structure itself. The double-walled casing design with controlled weak points embeds the bursting protection directly in the housing, eliminating the need for additional safety components.
Solution Approach 2:
The housing structure combines multiple functions: mechanical containment, sealing, and safety bursting protection. The double-walled casing with controlled weak points merges the structural integrity function with the safety release function into a single integrated design.
2Reliability
If fuse links are used for safety protection, then safety is improved, but cost increases
Solution Approach 1:
The patent uses inexpensive metallic housing materials with controlled weak points that can be manufactured at low cost through standard metal forming processes. The housing itself serves as the safety mechanism, eliminating expensive electronic fuses or complex membrane structures.
3Reliability
If the cell cup edge is beaded over for sealing, then liquid-tight sealing is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the sealing function from the mechanical beading process and relocates it to the gasket component. This separates the structural joining function (double-walled overlap) from the sealing function (gasket), simplifying the overall housing structure.
Solution Approach 2:
The gasket acts as an intermediary sealing element between the cell cup and cell cover. Instead of direct metal-to-metal sealing through beading, the gasket mediates the sealing function, allowing simpler overlap geometry while maintaining liquid-tight closure.
4Reliability
If electronic fuses are used for safety, then safety protection is improved, but cost increases significantly
Solution Approach 1:
The patent employs inexpensive metallic housing materials with predetermined weak points that can be manufactured using standard metal forming techniques. This mechanical safety approach is far cheaper than electronic fuses while providing adequate protection for the application.
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 manages overpressure by allowing the cell cover to be pushed out and creating a safety valve mechanism, preventing further current flow and reducing the risk of explosion, thus enhancing operational safety without the need for expensive electronic fuses.
Implementation Method 1
at least one hole passes through the casing of the cell cup in the area which overlaps the casing of the cell cover
Data Source
AI summary
A button cell has a housing closed in a liquid-tight manner including a cup, cover and seal, the cell cup having a base, circumferential casing, an edge area connecting the base and casing, and an end cut edge, the cell cover has a base, a circumferential casing, an edge area connecting the base and casing, and an end cut edge, the cover is inserted into the cup with the cut edge in front such that the casing of the cup and casing of the cover at least partially overlap and form a double-walled casing area, the seal is arranged between the cup and cover between the overlapping casing area such that they are isolated from one another, and at least one hole passes through the casing of the cup in the area which overlaps the casing of the cover.