Offset C-Shaped Vent in Alkaline Battery Can
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Solution Overview
Problem
Conventional alkaline electrochemical cells face issues with excessive gas pressure buildup due to the limited space for electrochemically active materials, as existing vent mechanisms either consume valuable volume or are susceptible to damage during manufacturing, and may not effectively release gases due to improper sealing.
Innovation Solution
A C-shaped pressure relief vent mechanism is formed in the closed end wall of the cell container, offset from the center, allowing for effective venting of excessive gases without obstructing the cover and providing a hinge for rupture, thus preventing damage and ensuring proper gas release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional C-shaped vent is formed in the bottom end wall, then pressure relief is achieved, but the vent may be susceptible to damage during manufacturing due to thin required thickness
Solution Approach 1:
The patent applies asymmetry by positioning the C-shaped vent offset from the center of the bottom end wall. This asymmetric placement allows the vent to be located in a region that experiences less stress during manufacturing processes like impact molding, thereby reducing susceptibility to damage while maintaining pressure relief functionality. The offset position creates a more favorable structural environment for the vent groove.
2Reliability
If the C-shaped vent is centered, then structural symmetry is maintained, but the vent may not effectively release gases due to improper sealing from the cover
Solution Approach 1:
The patent deliberately introduces asymmetry by offsetting the C-shaped vent from the center of the bottom end wall. This asymmetric positioning ensures that the vent opening is not blocked by the centrally located cover, allowing effective gas release. The offset creates a staggered arrangement where the vent and cover do not interfere with each other, solving the sealing problem while maintaining venting effectiveness.
3Reliability
If a vent mechanism is formed in the seal assembly, then pressure relief is achieved, but significant volume within the battery can is consumed
Solution Approach 1:
The patent moves the vent mechanism from the seal assembly (one location) to the bottom end wall (another dimension/location). By forming the C-shaped vent groove directly in the bottom end wall, the design eliminates the need for a separate vent structure in the seal assembly, thereby preserving valuable internal volume while maintaining pressure relief functionality. This dimensional relocation optimizes space utilization.
4Reliability
If the vent thickness is reduced to achieve acceptable vent pressure, then pressure relief sensitivity is improved, but the vent becomes susceptible to damage during manufacturing
Solution Approach 1:
The patent applies local quality by creating a localized reduced thickness region (the C-shaped groove) only where needed for pressure sensing, while maintaining adequate thickness in other areas. The offset positioning places this thin-walled groove in a structurally favorable location that experiences less overall stress, allowing the local thin section to be sensitive to pressure changes without being overly vulnerable to manufacturing damage.
Data Source
AI summary
An electrochemical cell is provided with an enhanced pressure relief vent formed in a closed end of the cell container that allows for effective venting of gas from the closed end of the container. The cell includes a container having a first end, a second end, a side wall extending between the first and second ends, and an end wall extending across the first end. The cell has a positive electrode, a negative electrode, and an aqueous alkaline electrolyte, all disposed in the container. The cell further includes a pressure relief vent mechanism having an offset C-shaped reduced thickness groove formed in the end wall of the container. A cover can be welded to the closed end wall of the container over the pressure relief vent mechanism.