Variable-Width Battery Separator for Wrinkle-Free Winding
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Solution Overview
Problem
Conventional separators used in wound type battery cells suffer from issues such as core pulling and wrinkling during the winding process, leading to poor battery cell quality.
Innovation Solution
A separator with distinct sections of varying widths, where the head and tail sections are narrower than the middle section, reducing friction with the winding needle and minimizing swing amplitude at the winding termination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the separator has a uniform width throughout its length, then the manufacturing process is simple, but core pulling occurs during winding due to excessive friction between the separator and winding needle
Solution Approach 1:
The separator is divided into three distinct sections along its length direction: a first section at the head, a second middle section, and a third section at the tail. The first and third sections have smaller widths than the second section, creating a segmented width structure that reduces contact area with the winding needle at critical locations, thereby preventing core pulling while maintaining manufacturing feasibility
Solution Approach 2:
Different sections of the separator are given different width characteristics tailored to their specific functional requirements. The head and tail sections have reduced widths to minimize friction during winding needle insertion and removal, while the middle section maintains a larger width to ensure proper electrode plate isolation. This local differentiation resolves the contradiction between manufacturing simplicity and winding reliability
2Reliability
If the separator width is reduced at the head and tail sections, then core pulling and wrinkling are prevented, but the separator structure becomes more complex
Solution Approach 1:
The separator structure is segmented into three width zones (first section with smaller width, second section with larger width, third section with smaller width) along the length direction. This segmentation addresses the reliability issue by preventing core pulling and tail wrinkling through reduced width at critical areas, while the segmentation itself provides a systematic and manufacturable solution rather than an overly complex design
Solution Approach 2:
The separator employs asymmetric width distribution where the head and tail sections have different widths compared to the middle section. This asymmetric design is strategically applied only where needed (at the head and tail) to solve specific problems, rather than making the entire separator complex, thus balancing reliability improvement with structural simplicity
Data Source
AI summary
Disclosed are a separator and a battery cell. The separator is used for being winded together with an electrode plate to prepare a battery cell, and the separator includes: a first section, a second section and a third section which are sequentially arranged in a length direction of the separator. A width of the first section is less than a width of the second section, and/or, a width of the third section is less than the width of the second section.