End Cap Assembly with Segmented Vent Apertures for High Power Cells
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Solution Overview
Problem
High power alkaline cells face issues with gas buildup and potential catastrophic rupture due to abusive discharge conditions, such as short circuiting, which can lead to rapid temperature increases and excessive gassing, necessitating an improved venting system to safely release gas pressure and prevent cell rupture.
Innovation Solution
The end cap assembly features a metal support disk with primary and secondary vent apertures, an integrally formed rupturable membrane in the insulating sealing disk, and protrusions to deflect ruptured membrane pieces, allowing rapid gas release when pressure exceeds a predetermined level, thereby preventing cell rupture and maintaining safe temperature levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single vent hole is provided in the end cap assembly, then the device complexity is reduced, but the venting speed is insufficient to prevent catastrophic rupture under abusive discharge conditions
Solution Approach 1:
The single vent hole is segmented into multiple vent holes (first vent hole and second vent hole) in the end cap assembly. This segmentation increases the total venting area and allows faster gas release under abusive discharge conditions, resolving the contradiction between simplified structure and adequate venting speed by using a multi-hole configuration rather than a single complex mechanism.
Solution Approach 2:
The vent holes are nested within the end cap assembly structure, with the vent holes formed as part of the integrated end cap design. This nesting approach allows multiple venting pathways to be incorporated without significantly increasing overall device complexity, as the vent holes are embedded within the existing end cap geometry rather than requiring separate external components.
2Reliability
If the end cap assembly is designed to withstand high radial compressive forces during crimping, then the mechanical seal tightness is improved, but the device complexity increases due to additional components like metal support disks
Solution Approach 1:
The metal support disk and end cap are merged into an integrated end cap assembly structure. The end cap includes both the sealing function and the structural support function in a single component, eliminating the need for separate metal support disks while maintaining the ability to withstand high radial compressive forces during crimping. This merging reduces device complexity while preserving mechanical seal tightness.
Solution Approach 2:
The end cap assembly is designed to perform multiple functions simultaneously: providing mechanical support to withstand radial compressive forces, creating a tight mechanical seal around the insulating member, and incorporating vent holes for gas release. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall device complexity while maintaining reliability.
3Ease of manufacture
If conventional single vent hole design is used, then manufacturing is simpler, but the venting capacity is insufficient to prevent catastrophic rupture under abusive conditions
Solution Approach 1:
The venting function is segmented into multiple holes within the end cap assembly. This segmentation increases the total venting capacity to handle abusive discharge conditions while maintaining manufacturing simplicity, as multiple holes can be formed using standard drilling or molding techniques during the end cap manufacturing process without requiring complex assembly steps.
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 venting system effectively prevents catastrophic rupture and maintains the cell housing temperature below 160°C during abusive conditions by rapidly releasing gas pressure, eliminating the need for additional thermal responsive devices like PTC devices.
Implementation Method 1
the membrane will rupture when gas pressure within the cell builds up to a level in excess of a predetermined level
Data Source
AI summary
And end cap assembly and venting system therein for closing and sealing the open end of a cell housing. The end cap assembly comprises a sealing disk underlying an end cap, and a metal support disk between the end cap and the sealing disk. The metal support disk has a plurality of primary vent apertures and a plurality of secondary vent apertures through its surface. The primary vent apertures are spaced apart along a path located at a greater distance from the central longitudinal axis of the metal support disk than the secondary vent apertures. The insulating sealing disk may have a thinned portion therein forming an rupturable membrane circumventing the central hub of the sealing disk. The insulating sealing disk may have protrusions emanating from its top surface to deflect the membrane during rupture. The venting system releases internal gases rapidly from the cell in the event of an abusive or short circuit discharge.