Battery Cell Pressure Relief Groove Structure for Low-Force Venting
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Solution Overview
Problem
Existing pressure relief apparatuses in battery cells often fail prematurely due to cracking when internal pressure is within normal ranges, leading to reduced long-term reliability.
Innovation Solution
A pressure relief apparatus with staged depressed and indented grooves is designed, where grooves are formed sequentially, reducing forming force and cracking risk, and featuring interlocking groove segments for enhanced pressure relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-stage indented groove is formed in the pressure relief portion, then the pressure relief apparatus can relieve pressure when threshold is reached, but the forming force is high which causes cracking and reduces long-term reliability
Solution Approach 1:
The single-stage indented groove is divided into multiple stages of depressed grooves and indented grooves formed in sequence. This segmentation reduces the forming force at each stage, preventing cracking of the pressure relief portion while maintaining the pressure relief function. The multi-stage structure allows gradual material deformation without exceeding strength limits.
Solution Approach 2:
Depressed grooves are formed in advance before forming the indented grooves. This preliminary action prepares the material by creating preliminary deformation zones, reducing the subsequent forming force required for indented grooves and preventing cracking during the pressure relief apparatus manufacturing process.
2Reliability
If the pressure relief portion is made strong to prevent cracking, then long-term reliability improves, but the pressure relief area is reduced and pressure relief rate decreases
Solution Approach 1:
The pressure relief portion has non-uniform structure with different groove depths and shapes at different locations. The multi-stage grooves create localized weak points that preferentially break under pressure, while other areas maintain structural strength. This local quality variation enables both high reliability and effective pressure relief.
Solution Approach 2:
The pressure relief structure extends into the thickness direction with multiple stages of grooves at different depths. This dimensional complexity creates a three-dimensional stress distribution that allows the material to maintain overall strength while providing sufficient pressure relief area through strategic weak point placement.
3Reliability
If multiple stages of grooves are formed sequentially, then forming force is reduced and cracking risk decreases, but the manufacturing process becomes more complex
Solution Approach 1:
Multiple groove forming operations are merged into a single integrated manufacturing process. The depressed grooves and indented grooves are formed in sequence as part of one continuous process flow, reducing the need for separate tooling and operations while achieving the reliability benefits of multi-stage forming.
Data Source
AI summary
A pressure relief apparatus includes a pressure relief portion provided with a first surface and a second surface arranged opposite to each other in a thickness direction of the pressure relief portion, and at least one stage of depressed groove and an indented groove. The at least one stage of depressed groove and the indented groove are formed in the pressure relief portion in sequence in a direction from the first surface to the second surface. A groove bottom wall of the stage of depressed groove farthest away from the first surface among the at least one stage of depressed groove is provided with an opening area. The indented groove is formed along an edge of the opening area. The opening area is configured to be openable with the stage of indented groove farthest away from the first surface as a boundary.