Dry Electrode Film Edge Protection for Uniform Calendering
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Solution Overview
Problem
Existing methods for manufacturing dry electrode films result in irregular edges and non-uniform widths, leading to cracking and material loss, which affects the electrochemical properties and consistency of batteries.
Innovation Solution
A method involving the introduction of a powdery polymer resin during the calendering process to create a protective edge, followed by removing a predetermined width of the edge part, ensuring a uniform and regular edge on the dry electrode film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a calendering process is used to manufacture dry electrode film, then the film can be formed efficiently, but the edges become irregular and sawtooth-like causing cracking
Solution Approach 1:
A protective layer is formed on the electrode mixture powder before the calendering process. This preliminary protective layer prevents the powder from being extruded at the edges during calendering, thereby avoiding irregular edge formation and cracking while maintaining manufacturing efficiency.
Solution Approach 2:
A protective layer acts as an intermediary between the electrode mixture powder and the calendering process. This protective layer is applied to the powder surface and removed after calendering, serving as a temporary mediator that prevents direct contact between the powder and the calendering rollers at the edges, thus preventing irregular edge formation.
2Manufacturing precision
If the sawtooth portion is cut to provide uniform boundary, then edge uniformity is improved, but significant material loss occurs
Solution Approach 1:
The protective layer is selectively removed after the calendering process. Since the protective layer is only present at the edges where it was applied for protection, removing it allows recovery of the underlying electrode material that would otherwise be wasted, while maintaining uniform edges.
Solution Approach 2:
The protective layer is discarded after serving its protective function during calendering, but the electrode material underneath is recovered. This approach allows the protective layer to be temporarily used and then removed, preventing material loss that would occur if the entire edge portion were discarded.
3Manufacturing precision
If drying apparatus is used to control solvent evaporation rate, then uniform drying is achieved, but manufacturing cost and time increase significantly
Solution Approach 1:
The electrode mixture powder is designed to undergo self-drying without requiring complex external drying apparatus. The powder composition and processing conditions are optimized to allow controlled solvent evaporation and binder fibrilization to occur naturally during the calendering process, eliminating the need for expensive and time-consuming separate drying equipment.
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 method produces a dry electrode film with a consistent width and reduced cracking, facilitating easier handling and minimizing material loss across batches.
Implementation Method 1
compressing the electrode mixture powder and the powdery polymer resin to be processed into a sheet-like electrode film member
Implementation Method 2
the binder is fibrilized by imparting shear force thereto through a process, such as jet milling or kneading
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3a
AI summary
Provided is a method and system for manufacturing a dry electrode film for an electrochemical device. The dry electrode film obtained by the method has a uniform and regular edge, and thus the dry electrode film can be controlled regularly to have a predetermined width. In addition, when using a roll-to-roll continuous process to manufacture a dry electrode film, it is possible to control the width of the dry electrode film uniformly during the manufacture. Further, since it is easy to control the width of the dry electrode film, it is possible to minimize a difference in dry electrode film width between one manufacture batch and another manufacture batch, even when the dry electrode film is manufactured through different manufacture batches. Additionally, since the dry electrode film has a uniform and regular edge boundary, it is significantly less likely that the dry electrode film is damaged due to cracking or the like, and the dry electrode film can be handled with ease.