Battery Cell Pressure Relief Structure for Fatigue-Resistant Venting
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Solution Overview
Problem
Pressure relief components in battery cells are prone to premature actuation or rupture due to fatigue, reducing the reliability and safety of battery cells over multiple cycles and long-term use.
Innovation Solution
A battery cell design with a pressure relief component featuring predetermined pressure relief regions and weak portions, optimized in size and structure to manage pressure effectively, reducing stress concentration and preventing untimely rupture, thereby enhancing reliability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure relief component is made thinner or with smaller area to reduce stress concentration, then the risk of premature actuation is reduced, but the pressure relief capability and strength are weakened
Solution Approach 1:
The pressure relief component employs different structural characteristics in different regions: the first weak portion has reduced thickness or area to facilitate controlled rupture, while other regions maintain sufficient strength. This local differentiation allows the component to have both low stress concentration at the rupture point and adequate overall strength for pressure relief.
Solution Approach 2:
The pressure relief component is divided into distinct functional regions including the first weak portion with predetermined rupture characteristics and other stronger portions. This segmentation allows each region to be optimized independently - the weak portion for reliable actuation and other portions for maintaining structural integrity.
2Strength
If the pressure relief component is made stronger or with larger area to improve pressure relief capability, then the bursting pressure increases, but the risk of premature actuation due to stress concentration also increases
Solution Approach 1:
The pressure relief component employs different structural characteristics in different regions: the first weak portion has reduced thickness or area to facilitate controlled rupture, while other regions maintain sufficient strength. This local differentiation allows the component to have both low stress concentration at the rupture point and adequate overall strength for pressure relief.
Solution Approach 2:
The pressure relief component is divided into distinct functional regions including the first weak portion with predetermined rupture characteristics and other stronger portions. This segmentation allows each region to be optimized independently - the weak portion for reliable actuation and other portions for maintaining structural integrity.
3Reliability
If the first weak section has smaller cross-sectional area to reduce stress concentration, then premature actuation risk is reduced, but the pressure relief effectiveness may be compromised
Solution Approach 1:
The first weak section has specifically optimized cross-sectional area (0.1mm≤A≤0.3mm and 0.06mm≤H≤0.5mm) that balances two requirements: small enough to reduce stress concentration and prevent premature actuation, but large enough to provide effective pressure relief when activated. This local quality optimization ensures both reliability and effectiveness.
Data Source
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AI summary
The present application relates to the technical field of batteries. Provided are a battery cell, a battery, and an electric device. The battery cell comprises: a casing and a pressure relief component, wherein the casing comprises a first wall portion; and the pressure relief component is arranged on the first wall portion, a first weak portion of the pressure relief component defining at least one predetermined pressure relief region, the pressure relief component being configured to crack along at least part of the first weak portion during pressure relief of the battery cell. The sum of the area of the predetermined pressure relief region is S, and the first weak portion comprises at least one first weak section, the cross-sectional area of the first weak section that is perpendicular to the extension direction thereof being S1, wherein 300 mm2 ≤ S ≤ 1500 mm2, and 0.006 mm2 ≤ S1 ≤ 0.15 mm2. Thus, risks such as premature actuation and fatigue cracking of the pressure relief component occurring at the first weak portion after long-term use of the battery cell and causing the problem of liquid leakage can be reduced, and risks such as bursting, explosion, and ignition occuring in the casing of the battery cell due to the pressure relief component failing to relieve pressure in a timely manner can also be reduced, thereby improving the use reliability of the battery cell.