Jelly-Roll Electrode Assembly With Dual-Alumina Separator Roughness Control
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Solution Overview
Problem
The application of a double-sided SRS separator in jelly-roll type electrode assemblies is hindered by surface roughness issues between the separator and the mandrel, leading to reduced process yield and safety concerns due to frictional forces and damage during the winding process.
Innovation Solution
A jelly-roll type electrode assembly with a double-sided SRS separator having a specific mixture of first and second alumina in the coating layer, along with adjusted surface roughness of the mandrel, is used to minimize friction and prevent damage during the winding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-sided SRS separator is applied to improve heat resistance and safety, then thermal properties are improved, but surface roughness causes increased friction with the mandrel leading to reduced process yield
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness of the SRS separator within a specific range (Ra 0.3μm to 1.0μm) to optimize both heat resistance and processability. This parameter optimization resolves the contradiction by finding the optimal roughness level that provides sufficient thermal protection while maintaining acceptable friction characteristics during mandrel removal
Solution Approach 2:
The patent uses composite materials by combining ceramic particles (alumina, silica, titania) with polymer binders to create the SRS separator coating layer. This composite structure provides both the required thermal resistance and controlled surface properties, balancing safety requirements with manufacturing processability
2Reliability
If a double-sided SRS separator is applied to improve heat resistance, then thermal safety is improved, but frictional force between separator and mandrel increases causing slip conditions and tail out conditions
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface roughness parameter (Ra) of the separator within the range of 0.3μm to 1.0μm. This optimized roughness parameter reduces excessive friction between the separator and mandrel, preventing slip conditions and tail out conditions during mandrel removal, while maintaining the thermal safety benefits of the SRS separator
Solution Approach 2:
The patent applies local quality by differentiating the surface properties of the separator - the SRS coating layer is applied only on specific surfaces where thermal protection is needed, while controlling the surface roughness locally to ensure proper interaction with the mandrel during winding and removal processes
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
The solution enhances the heat resistance and safety of the electrode assembly while improving the process yield by optimizing the surface roughness of the separator and mandrel, reducing slip conditions and damage during mandrel removal.
Implementation Method 1
the coating layer includes a mixture of a first alumina and a second alumina... the separator has a surface roughness (Ra) of 500 nm to 1 μm
Implementation Method 2
has a function of having ion conductivity by providing a path through which ions can move between two electrodes through electrolyte supported in micropores
Implementation Method 3
there is a problem that the process yield is slightly lowered by a surface roughness value of a SRS separator and a mandrel, or a frictional force between the SRS separator and the mandrel
Data Source
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AI summary
A jelly-roll type electrode assembly according to an embodiment of the present disclosure is a jelly-roll type electrode assembly in which a sheet-like laminate including an electrode and a separator is wound, wherein the separator includes a double-sided coating layer, the coating layer includes a mixture of a first alumina and a second alumina, the second alumina is contained in an amount of 16 to 40 parts by weight based on 100 parts by weight of the mixture, and a particle diameter of the first alumina is smaller than a particle diameter of the second alumina.