Cylindrical Battery Crimp Region Double Bend Structure
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Solution Overview
Problem
Conventional cylindrical secondary batteries face issues with sealability and safety due to deformation under external impacts and increased internal pressure, leading to electrolyte leakage, and the insulative tubes used have low impact resistance and environmental concerns.
Innovation Solution
A crimp region structure is developed with a continuous double bend at the upper end of the cylindrical container, where the first bent area has a smaller radius of curvature (R1) and the second bent area has a larger radius (R2), along with a rectilinear area and a bent front end that presses the gasket, enhancing sealing and mechanical strength, and an insulative film made of soft PET resin is used for improved impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the upper end of the container is bent with a small radius of curvature to prevent deformation under external impacts, then the mechanical strength and sealability are improved, but wrinkles may form on the container surface
Solution Approach 1:
The bending process is divided into two distinct stages: first bending the upper end of the container with a larger radius of curvature (R1) to avoid wrinkles, then bending the front end with a smaller radius of curvature (R2) to create the pressing structure. This segmentation allows each bending stage to optimize for its specific function without causing the adverse effect of wrinkles.
Solution Approach 2:
The first bending operation with radius R1 is performed as a preliminary action before the second bending with radius R2. This preliminary bending creates a prepared structure that can subsequently be bent into the final pressing configuration without forming wrinkles during the critical second bending stage.
2Reliability
If the crimp region is bent with a small radius of curvature to maintain sealability under internal pressure, then the sealing performance is improved, but the container may deform under external impacts
Solution Approach 1:
Different regions of the crimp structure are given different bending radii to optimize their specific functions: the first bent area (R1) provides a gentler curve for overall structural integrity and resistance to external impacts, while the second bent area (R2) with smaller radius creates the concentrated pressing force needed for sealability under internal pressure. This local differentiation of geometric properties resolves the contradiction between the two opposing requirements.
3Ease of manufacture
If conventional insulative tubes are used to cover the container, then the manufacturing process is simple, but the impact resistance is low and environmental concerns arise
Solution Approach 1:
The material properties of the insulative covering are changed from conventional materials to soft PET resin, which provides superior impact absorption capabilities and environmental benefits. This parameter change in material selection maintains ease of manufacture through familiar processing techniques while dramatically improving impact resistance and environmental compatibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly improves the sealability and safety of the battery by preventing electrolyte leakage and minimizing deformation, while the soft PET resin insulative film enhances impact absorption and prevents external short circuits.
Implementation Method 1
the crimp region is constructed in a structure in which the upper end of the crimp region of the cylindrical container is continuously bent twice with predetermined radii of curvature, and therefore, when external physical impacts, such as vibration or dropping, are applied to the battery, and when the internal pressure of the battery increases, the sealed portions are restrained from being separated from each other
Implementation Method 2
the deformation of the container, such as wrinkles, is minimized when bending the front end of the crimp region with a small radius of curvature
Implementation Method 3
an insulative film made of soft PET resin is used for improved impact resistance
Data Source
Figure 1~2
Figure 3~4
AI summary
Disclosed herein is a cylindrical battery constructed in a structure in which a crimp region, at which a cap assembly is mounted to an open upper end of a cylindrical container having an electrode assembly mounted therein, is formed at the upper end of the container, wherein the crimp region is constructed in a structure in which the upper end of the crimp region is gently bent, such that the crimp region surrounds a gasket located at the inside of the crimp region, a bent front end is continuously bent twice to press the gasket, while the bent front end extends inward, such that a radius of curvature (R1) of the first bent area is less than a radius of curvature (R2) of the second bent area. The cylindrical battery according to the present invention is constructed such that the upper end of the crimp region of the cylindrical container is continuously bent twice in a predetermined condition. Consequently, when external physical impacts, such as vibration or dropping, are applied to the battery, and when the internal pressure of the battery increases, the sealed portions are restrained from being separated from each other, thereby preventing the leakage of an electrolyte and thus greatly improving the safety of the battery. Furthermore, it is possible to minimize the deformation of the container, such as wrinkles, which may be formed due to failure to form the bent area gently when bending the front end of the crimp region with a small radius of curvature.