Reverse-Flow Electrode Drying to Prevent Binder Migration
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Solution Overview
Problem
The quality of secondary batteries can be deteriorated during the drying process due to the migration of binders in the slurry, leading to non-uniform drying and potential defects in the electrode structure.
Innovation Solution
An apparatus is designed with a drying part that supplies hot air opposite to the moving direction of the electrode plate, using elongated slit-shaped nozzles for uniform drying, and exhausts used gas in the upstream direction to maintain consistent drying across the width of the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the slurry is dried by conventional drying methods, then the drying process can be completed, but the binder migrates in the slurry causing non-uniform drying and quality deterioration
Solution Approach 1:
The gas supply nozzle directs gas in the opposite direction to the moving direction of the electrode plate. This reverse flow pattern prevents binder migration by creating a uniform drying environment from the trailing edge toward the leading edge, eliminating the non-uniform drying that occurs with conventional forward-direction drying methods.
Solution Approach 2:
The gas supply nozzle is designed with an elongated slit shape positioned at the downstream end, creating localized gas supply at the trailing edge of the electrode plate. This localized approach ensures that drying starts from the region most prone to binder migration and progresses uniformly across the entire slurry area, preventing quality deterioration.
2Productivity
If gas is supplied to dry the slurry, then drying efficiency is improved, but edge overdrying occurs leading to non-uniform drying quality
Solution Approach 1:
The gas supply nozzle is positioned at the downstream end (trailing edge) rather than spanning the entire width or positioned at the upstream end. This localized positioning concentrates the drying action where it is most needed while preventing excessive gas exposure at the edges, thereby maintaining both high drying efficiency and uniform drying quality without edge overdrying.
Solution Approach 2:
By directing gas from the downstream end opposite to the moving direction, the drying process progresses uniformly from trailing edge to leading edge. This reverse-direction approach ensures that all regions of the slurry receive equivalent drying exposure, preventing the edge overdrying that occurs with conventional upstream or centered gas supply methods.
3Device complexity
If conventional drying apparatus is used, then the structure is simple, but binder migration causes defects in electrode structure
Solution Approach 1:
The core modification to the conventional drying apparatus is the reversal of gas flow direction - supplying gas from the downstream end opposite to the moving direction rather than from the upstream end or center. This single directional change prevents binder migration and electrode structure defects while maintaining the overall simplicity of the drying apparatus structure.
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 apparatus ensures uniform drying of the slurry on the electrode substrate, preventing overdrying at the edges and enhancing the adhesive strength and density of the dried layers.
Implementation Method 1
the slurry coated on the substrate is dried as a solvent forming a part of the slurry evaporates
Implementation Method 2
an exhaust nozzle passing through the lower surface of the housing, in fluid communication with the exhaust chamber, and configured to suck in gas that has been used to dry the slurry
Data Source
AI summary
An apparatus for drying an electrode may include a drying part configured to be positioned above a moving electrode plate and to direct gas in a direction opposite to a moving direction of the electrode plate to dry a slurry formed on a substrate of the electrode plate. and the drying part may also be configured to suck gas that has been used to dry the slurry. A gas supply part configured to supply the gas to the drying part, and an exhaust part configured to discharge the gas sucked into the drying part to outside of the apparatus.