Uneven Hygroscopic Film for Uniform Drying of Stacked Electrodes
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Solution Overview
Problem
The existing electrode drying methods for secondary batteries face challenges in uniformly drying electrodes, particularly those in the middle of a stacked configuration or at the core of a wound electrode sheet, leading to moisture content differences and reduced battery performance, requiring extended drying times or high temperatures that can damage the electrodes.
Innovation Solution
The method involves interposing a hygroscopic film with an uneven structure between electrodes or an electrode sheet, creating air flow paths that facilitate even drying, using materials like polyvinyl alcohol resin with adsorptive coatings to enhance moisture absorption and reduce drying time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrodes are stacked and dried together to improve manufacturing efficiency, then productivity increases, but moisture content uniformity deteriorates
Solution Approach 1:
A hygroscopic film is introduced as an intermediary substance between stacked electrodes. This film actively absorbs moisture from the electrode surfaces through capillary action and hygroscopic properties, mediating the drying process to achieve uniform moisture removal across all electrodes in the stack without requiring extended drying times
Solution Approach 2:
The hygroscopic film utilizes porous structures with controlled pore sizes and distributions to enhance moisture absorption capacity. The porous architecture provides extensive surface area and capillary channels that facilitate rapid and uniform moisture extraction from electrode surfaces while maintaining structural integrity during the drying process
2Manufacturing precision
If drying time is extended to dry middle electrodes sufficiently, then moisture content uniformity improves, but productivity decreases
Solution Approach 1:
The hygroscopic film is pre-positioned between electrodes before the drying process begins. This preliminary arrangement ensures that moisture absorption capacity is already distributed throughout the electrode stack, enabling rapid and uniform drying from the outset without requiring extended drying times to achieve moisture uniformity in middle electrodes
3Productivity
If drying temperature is increased to reduce drying time, then productivity improves, but electrode quality deteriorates
Solution Approach 1:
The drying mechanism is substituted from thermal-driven evaporation to moisture-absorption-driven removal. Instead of relying on high temperature to evaporate moisture, the hygroscopic film passively absorbs moisture through capillary action and hygroscopic properties, enabling low-temperature drying that preserves electrode quality while achieving short drying times
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
This approach allows for nearly uniform drying of electrodes across the stack or wound sheet, significantly reducing drying time and moisture content differences, thereby improving battery performance and manufacturing efficiency.
Implementation Method 1
a hygroscopic film having an uneven structure is interposed between the electrodes
Implementation Method 2
using materials like polyvinyl alcohol resin with adsorptive coatings to enhance moisture absorption
Implementation Method 3
creating air flow paths that facilitate even drying
Data Source
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AI summary
Disclosed herein is an electrode drying method for drying a plurality of electrodes in the state in which the electrodes are stacked, the electrode drying method including interposing a hygroscopic film between the electrodes and drying the electrodes in the state in which the hygroscopic film is interposed between the electrodes, wherein at least one of the surfaces of the hygroscopic film that face the electrodes has an uneven structure, or an electrode drying method for drying an electrode sheet in the state in which the electrode sheet is wound, the electrode drying method including winding the electrode sheet with a hygroscopic film and drying the electrode sheet in the state in which the hygroscopic film is interposed between overlapping portions of the electrode sheet, wherein at least one of the surfaces of the hygroscopic film that are opposite the electrode sheet has an uneven structure.