Battery Separator Roll Core Surface Roughness for Reuse
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Solution Overview
Problem
Existing separator rolls for lithium-ion batteries do not allow for the reuse of the core after the separator has been wound off, leading to inefficiencies and increased costs in battery production.
Innovation Solution
A separator roll design featuring a core with an outer surface roughness of at least 3.7 μm arithmetic mean or 4.0 μm root mean square, which reduces the peel strength and enables easy removal of the separator, allowing for core reuse and preventing misalignment during winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the core surface is made smooth for easy winding of separator, then the winding process is simplified, but the separator adheres strongly to the core making reuse difficult
Solution Approach 1:
The invention changes the surface roughness parameter of the core from smooth to specifically rough (Ra≥3.7μm or Rms≥4.0μm). This parameter change creates micro-voids between the separator and core surface, reducing adhesion strength while still allowing effective winding. The rough surface enables both easy winding and easy removal, resolving the contradiction between these two requirements.
2Manufacturing precision
If adhesive is used to fix separator to core, then separator positioning is improved, but core reuse becomes difficult due to strong adhesion
Solution Approach 1:
The invention changes the surface parameter from smooth to rough (Ra≥3.7μm or Rms≥4.0μm), which reduces adhesion strength while maintaining positioning capability through mechanical interlocking. The rough surface creates micro-voids that prevent strong adhesive bonding, allowing separator removal and core reuse while still achieving adequate positioning during winding.
Solution Approach 2:
The invention extracts or eliminates the adhesive component from the system by relying on the rough surface geometry alone for separator fixation. By removing the adhesive element and using only the roughened surface, the system achieves both positioning and reusability without the strong adhesion that would prevent core reuse.
3Ease of manufacture
If conventional smooth core is used, then production cost is lower, but core cannot be reused leading to higher long-term costs
Solution Approach 1:
The invention modifies the core surface parameter from smooth to rough (Ra≥3.7μm or Rms≥4.0μm), which enables separator removal and core reuse. Although this requires an additional surface treatment step, the ability to reuse cores multiple times eliminates the need for continuous core replacement, resulting in lower long-term production costs and improved productivity.
Solution Approach 2:
The invention enables the recovery and reuse of the core after separator removal. By creating a rough surface that allows easy separator detachment, the core can be recovered and reused for subsequent separator winding operations, transforming a single-use component into a reusable one and improving overall production efficiency.
Data Source
AI summary
The present invention provides a separator roll (10) and the like including a core suited for reuse. The separator roll (10) includes: a porous separator (12) for use in a battery; and a core (8) around which the separator (12) is wound. The outer circumferential surface (S) of the core (8) has arithmetic mean roughness of not less than 3.7 μm, the outer circumferential surface (S) being in contact with the separator (12).