Gradient-Thickness Separator for Zigzag Electrode Hot-Pressing
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Solution Overview
Problem
Conventional electrode assemblies, particularly those using the zigzag-stacking method, face issues with thickness deformation and pore damage due to heat and pressure applied during the hot-pressing process, leading to poor insulating properties and safety concerns.
Innovation Solution
A separator with a porous substrate and a porous coating layer, where the substrate thickness gradually decreases and the coating layer thickness gradually increases towards the ends, maintaining a constant total thickness, is used to minimize deformation and damage, enhancing insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heat and pressure are applied to the entire stacked electrode assembly during hot-pressing, then the electrode assembly is fixed and manufactured, but thickness deformation and pore damage occur at the top and bottom ends
Solution Approach 1:
The separator is designed with gradient thickness where the thickness gradually decreases from the central portion toward both ends in the longitudinal direction. This non-uniform thickness distribution allows the thinner end regions to accommodate compression during hot-pressing, reducing thickness deformation and pore damage at these locations while maintaining adequate separation in the central region.
2Ease of manufacture
If heat and pressure are applied to the entire stacked electrode assembly during hot-pressing, then the electrode assembly is fixed and manufactured, but damage to the porous structure occurs
Solution Approach 1:
The separator employs gradient thickness design with a porous coating layer on the porous substrate. The varying thickness creates regions of different mechanical strength and compressibility, allowing the thinner end portions to absorb hot-pressing stress without damaging the porous structure, thereby preventing pore collapse and maintaining ion transport pathways.
3Device complexity
If uniform thickness separator is used, then manufacturing is simple, but thickness deformation occurs at the ends during hot-pressing
Solution Approach 1:
The separator's thickness parameter is changed from uniform to gradient distribution. The thickness gradually decreases from the central portion toward both ends, creating a profile that anticipates and accommodates the non-uniform pressure distribution during hot-pressing, thereby minimizing thickness deformation at the end regions.
Data Source
AI summary
The present disclosure relates to an electrode assembly and an electrochemical device including the same. The electrode assembly includes a unit electrode and a strip-shaped separator being foldable in a zigzag manner, in which the unit electrode is disposed in an overlapped portion of the separator when the separator is folded. The separator includes a porous substrate of a polymeric material and a porous coating layer containing organic particles and provided on each of the upper and lower surfaces of the porous substrate. The thickness (Ts) of the porous substrate gradually decreases towards longitudinal ends from the longitudinal center, the total thickness (Tc) of the porous coating layer gradually increases towards either longitudinal end thereof, and the total thickness (Ts+Tc) is constant across the entire plane of the separator.