Reform Pin Geometry for Stable Electrode Assembly Removal
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Solution Overview
Problem
Existing reform pins for cylindrical batteries face difficulties in uniformly forming a jelly-roll shape due to surface contact issues and inefficiencies in removing the separation membrane, particularly when inserting or removing the pin near the negative electrode tab.
Innovation Solution
A reform pin with a cylindrical body and a head portion having a larger diameter at specific points, featuring a conical and frustoconical shape, which reduces contact surface area and allows for stable insertion and removal without lifting the separation membrane, enabling efficient reforming of both positive and negative electrode tabs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a reform pin with a conical head portion is used for reforming the electrode assembly, then the reforming process can be performed, but the electrode assembly and the reform pin are in surface contact which makes it difficult to remove the separation membrane and perform reforming in the direction of the negative electrode tab
Solution Approach 1:
The reform pin is divided into multiple sections with different diameters: a first diameter for the main body and a second diameter for the head portion. This segmentation allows the pin to interact differently with various parts of the electrode assembly, enabling effective reforming near the negative electrode tab while maintaining ease of separation membrane removal.
Solution Approach 2:
Different portions of the reform pin have different local properties - the head portion has a larger diameter than the main body. This local quality variation allows the pin to provide targeted reforming action where needed (near the negative electrode tab) while maintaining overall structural integrity and ease of operation.
2Productivity
If a reform pin with a conical head portion is used, then the reforming process can be performed, but the surface contact between the electrode assembly and the reform pin makes it difficult to remove the reform pin without lifting the separation membrane
Solution Approach 1:
The reform pin features a segmented diameter structure with a smaller main body diameter and a larger head portion diameter. This segmentation creates a controlled contact interface that maintains sufficient friction for effective reforming while allowing clean removal without lifting the separation membrane.
Solution Approach 2:
The diameter parameter of the reform pin is varied along its length, with the head portion having a second diameter and the main body having a first diameter. This parameter change optimizes the balance between reforming effectiveness (requiring sufficient contact) and ease of removal (requiring reduced contact area).
Data Source
AI summary
A reform pin is provided in which one end of a head portion extending from a body portion is provided thicker than the body portion, so that a contact surface with an inner surface of an electrode assembly is reduced when an inserted reform pin is removed from the electrode assembly, thereby stably removing the reform pin without lifting of a separation membrane. In addition, a vertex of the head portion is formed to be inclined to one side, such that it is possible to provide a high-performance and highly reliable reform pin that may be easily inserted while avoiding the separation membrane in which a lifting phenomenon occurs when the reform pin is inserted into the hollow portion of the electrode assembly.