Battery Cell Vent Weakening Layout for Reliable Pressure Relief
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Solution Overview
Problem
Pressure relief mechanisms in batteries often open prematurely, leading to failure in achieving normal pressure relief functions.
Innovation Solution
The weakened portion on the battery cell's wall is positioned at least 0.3 times the minimum radial dimension away from the center point, closer to the edge, with varying thicknesses and configurations to enhance resistance to deformation and fatigue, ensuring it ruptures only when internal pressure reaches activation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the weakened portion is positioned closer to the center of the wall portion, then the pressure relief activation pressure is reduced, but the weakened portion becomes more prone to fatigue failure and premature opening
Solution Approach 1:
The patent applies local quality by positioning the weakened portion in a specific region of the wall portion where the material properties and stress distribution are optimized. The weakened portion is placed in a region that balances between achieving sufficient pressure relief activation pressure and maintaining resistance to fatigue failure, rather than being uniformly distributed or positioned at the center.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a single-point positioning approach to a regional positioning approach. Instead of specifying a single location for the weakened portion, the patent defines a specific region on the wall portion where the weakened portion should be located, considering multiple spatial dimensions and the complex stress distribution pattern.
2Reliability
If the weakened portion is positioned closer to the edge of the wall portion, then the resistance to deformation and fatigue is improved, but the pressure relief activation pressure increases
Solution Approach 1:
The patent applies local quality by selecting a specific region on the wall portion that optimizes the balance between structural integrity and pressure relief functionality. The weakened portion is positioned in a region where the material has sufficient strength to resist deformation and fatigue while still allowing for effective pressure relief at appropriate activation pressure.
Solution Approach 2:
The patent resolves this contradiction by defining a regional positioning approach rather than single-point positioning. The specific region is determined by considering multiple spatial dimensions and the complex interaction between structural strength requirements and pressure relief activation pressure requirements.
3Stress or pressure
If the weakened portion is positioned at the center of the wall portion, then the pressure relief function is activated at lower pressure, but the premature opening risk increases due to lower rigidity
Solution Approach 1:
The patent applies local quality by positioning the weakened portion in a specific region of the wall portion that provides optimal balance between pressure relief activation and structural strength. This region is characterized by appropriate rigidity to prevent premature opening while enabling pressure relief function to activate at the desired pressure level.
Solution Approach 2:
The patent resolves the contradiction by transitioning from center-point positioning to regional positioning. The specific region is defined by considering multiple spatial dimensions and the complex stress distribution pattern in the wall portion, allowing optimization of both activation pressure and structural strength simultaneously.
Data Source
AI summary
A battery cell includes a casing with a wall portion having a weakened portion configured to rupture when internal pressure is released. The outer surface of the wall portion has a center point. A minimum distance between a projection of the weakened portion and the center point is defined as a, and a minimum radial dimension of the outer surface is defined as A, where a is greater than or equal to 0.3A. The weakened portion is positioned farther from the center and closer to the edge of the wall portion. The edge area has greater rigidity, deformation resistance, and fatigue resistance compared to the center. Placing the weakened portion near the edge reduces the likelihood of fatigue failure under gas pressure and helps prevent premature rupture, thereby improving pressure release reliability and maintaining normal battery cell operation.