Cylindrical Battery Lid Vent Layout to Prevent Projectile Pop-Out
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cylindrical secondary batteries face safety issues due to uniform gas ejection through equally sized and shaped openings in the battery lid, leading to projectile-like popping out during abnormal conditions, which decreases pass rates in combustion and drop tests.
Innovation Solution
The battery lid features non-overlapping, asymmetrically arranged opening portions with a cleavage impression, ensuring non-uniform gas ejection and enhanced structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple opening portions with the same dimensions and shape are arranged at equal intervals in the battery lid, then gas can be released uniformly from each opening, but the battery may pop out like a projectile during abnormal conditions
Solution Approach 1:
The patent applies asymmetry by configuring opening portions with different shapes and/or dimensions, or arranging them at non-equal intervals in the circumferential direction. This asymmetric configuration ensures that gas ejection forces are not uniformly distributed, preventing the battery from popping out like a projectile while maintaining effective gas release functionality.
2Reliability
If opening portions are provided in the battery lid for gas release, then gas can be vented during abnormal conditions, but the strength of the battery lid is reduced
Solution Approach 1:
The patent applies local quality by providing reinforcement portions in the battery lid at specific locations, particularly around the opening portions. These reinforcement portions have different properties (higher strength, different thickness) compared to other areas of the lid, allowing the structure to maintain overall strength while accommodating the necessary gas release openings.
3Ease of manufacture
If opening portions are arranged at equal intervals with line symmetry, then the structure is simple and manufacturable, but the battery may fly out like a projectile due to uniform gas ejection
Solution Approach 1:
The patent deliberately introduces asymmetry in the arrangement and configuration of opening portions, departing from equal interval and line-symmetric patterns. This asymmetric design, while slightly more complex to manufacture, effectively prevents uniform gas ejection and the resulting projectile pop-out hazard.
Data Source
AI summary
A cylindrical secondary battery is provided and including: an electrode wound body having a structure in which a band-shaped positive electrode and a band-shaped negative electrode are stacked and wound with a separator interposed therebetween; a battery can accommodating the electrode wound body with one end portion being open while the electrode wound body is accommodated; and a battery lid provided at the one end portion of the battery can and having two or more opening portions, wherein the two or more opening portions have a non-overlapping form during rotation that does not overlap the two or more opening portions before rotation when the two or more opening portions are rotated by more than 0° and less than 360° about an axis of a cylindrical shape of the secondary battery in top view, and the battery lid has a cleavage impression at any one of joints between two adjacent opening portions out of the two or more opening portions.