Gradient Roller Calendaring for Sub-80 μm Electrode Sheets
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Solution Overview
Problem
Conventional solvent-free electrode fabrication processes struggle to produce electrodes with active material layers thinner than 100 μm, which are necessary for improved performance and packaging considerations in rechargeable lithium-ion batteries.
Innovation Solution
A method involving a system of rollers with increasing radiuses is used to calendar and laminate active material films, allowing for the production of electrodes with thicknesses less than 80 μm, utilizing a sequence of rollers with progressively larger diameters and controlled rotational speeds to achieve the desired thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solvent-free electrode fabrication process is used, then manufacturing simplicity is maintained, but active material layer thickness cannot be reduced below 100 μm
Solution Approach 1:
The calendaring process is divided into multiple stages using different roller configurations. First, a conventional calendaring step is performed, followed by a second calendaring step using rollers with smaller diameters and adjusted gaps to achieve the target thickness of less than 100 μm. This segmentation allows thickness precision without excessive complexity in any single step.
Solution Approach 2:
The system dynamically adjusts roller gap dimensions and roller diameter based on the calendaring stage. The first calendaring uses larger rollers with larger gaps, while the second calendaring uses smaller rollers with precisely controlled smaller gaps. This dynamic adaptation enables achievement of thin layer thicknesses while maintaining manufacturing feasibility.
2Productivity
If active material layer thickness is reduced below 100 μm, then battery performance and packaging efficiency are improved, but conventional fabrication processes fail to achieve the desired thickness
Solution Approach 1:
The calendaring operation is segmented into at least two distinct stages: a first calendaring step that reduces thickness to an intermediate level, and a second calendaring step using rollers with smaller diameters and adjusted gaps that achieves the final thickness of less than 100 μm. This multi-stage approach enables precise thickness control that would be unattainable in a single step.
Solution Approach 2:
The system changes critical parameters between calendaring stages: roller diameter is reduced in the second stage, and roller gap is precisely adjusted to smaller values. These parameter changes enable the fabrication of ultra-thin active material layers (less than 100 μm) with controlled thickness, directly improving battery performance and packaging efficiency.
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
Enables the manufacturing of high-nickel cathodes with thicknesses less than 80 μm, enhancing performance and packaging efficiency in lithium-ion batteries.
Implementation Method 1
one or more pairs of calendaring rollers compresses a dry mixture of active materials, binders, and other materials to form an active electrode layer to a desired thickness
Implementation Method 2
laminates the compressed active electrode layer on the current collector
Data Source
AI summary
A system and method for manufacturing an electrode sheet. The system includes groups of rollers having increasing diameter gradient to calendar an active material film having an initial thickness to a predetermined production thickness. The initial thickness is continually reduced as the active material film is calendared through the group of rollers. The groups of rollers includes a first group of rollers and a second group of rollers disposed immediately downstream of the first group of rollers. The first group of rollers includes a first roller radius and the second group of rollers includes a second roller radius greater than the first roller radius. The first group of rollers includes a first gap between adjacent rollers and the second group of rollers includes a second gap between adjacent rollers, in which the second gap is equal to or less than the first gap.