Bursting Membrane Sizing for Prismatic Battery Cell Venting
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Solution Overview
Problem
Existing battery cells face challenges in efficiently venting gases while maintaining mechanical stability and minimizing weight, due to the need for thick materials to secure rupture membranes, which compromises energy density and can impede gas flow through electrical connections.
Innovation Solution
A membrane arrangement for battery cells with a rupture membrane positioned on a narrow side of a prismatic cell housing, dimensioned to optimize cross-sectional area and mechanical stability, allowing for efficient gas venting and secure attachment without increasing material thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rupture membrane is externally connected to the cell lid by welding, then a reliable connection is ensured, but the material thickness of both the rupture membrane and cell lid must be increased
Solution Approach 1:
The rupture membrane is extracted from the cell lid and repositioned on the narrow side of the cell housing. This separation allows the membrane to be integrated into a location that does not compromise the structural integrity or require increased material thickness of the cell lid, thereby maintaining connection reliability without increasing overall weight.
Solution Approach 2:
The rupture membrane is moved from the top surface (cell lid) to the lateral surface (narrow side) of the cell housing. This dimensional relocation enables the membrane to be positioned where it can be securely attached without requiring additional material thickness in critical load-bearing areas, thus resolving the contradiction between connection reliability and weight.
2Reliability
If the rupture membrane is installed in the cell lid, then connection reliability is improved, but gas venting efficiency is reduced due to electrical connections impeding gas channels
Solution Approach 1:
The rupture membrane is extracted from the cell lid location and repositioned on the narrow side of the cell housing. This removes the interference of electrical connections from the gas venting path, allowing unobstructed gas flow while the membrane maintains its secure attachment to the cell housing structure.
Solution Approach 2:
By relocating the rupture membrane from the vertical dimension (cell lid) to the lateral dimension (narrow side), the gas venting channel is freed from electrical connection obstructions. This spatial reconfiguration enables efficient gas egress while preserving connection reliability through appropriate attachment methods on the narrow side.
3Productivity
If the rupture membrane cross-sectional area is increased, then gas venting speed is improved, but the mechanical stability of the cell casing is compromised
Solution Approach 1:
The rupture membrane is positioned on the narrow side of the cell housing, utilizing the local geometric characteristics of this area. The membrane dimensions are optimized relative to the narrow side dimensions (membrane length: 0.25-0.4 times cell length, membrane width: 0.44-0.6 times cell width), creating sufficient circumferential space for seals and welds while maintaining adequate cross-sectional area for efficient gas venting without compromising overall structural stability.
Data Source
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AI summary
The invention relates to a membrane arrangement for a battery cell, comprising a cell housing with a prismatic shape and a rupture membrane, wherein the cell housing has at least two side faces and at least two narrow sides, wherein the cell housing has a length, a width, and a height, and wherein the rupture membrane has a membrane length and a membrane width, wherein the rupture membrane is positioned in or on a narrow side of the cell housing, wherein the rupture membrane has a membrane length corresponding to 0.25 to 0.4 times the length of the cell housing, and wherein the rupture membrane has a membrane width corresponding to 0.44 to 0.6 times the width of the cell housing. The invention further relates to a battery cell.