Separator Coating Bar for Thicker Edge Adhesion Layers
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Solution Overview
Problem
Existing coating methods, such as wire bar coating, fail to form a coating layer with varying thicknesses, leading to inadequate adhesive strength between the separator and electrode, particularly at the ends, which can result in adhesion failure.
Innovation Solution
A coating bar design with a cylindrical bar having smaller diameters at the ends and larger wire diameters at the ends is used to apply a slurry, ensuring a thicker coating layer at the ends, thereby enhancing adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a uniform wire diameter is used in the coating bar, then the coating process is simple, but the coating layer thickness is uniform and cannot be increased at the ends to improve adhesion
Solution Approach 1:
The patent applies local quality by varying the wire diameter at different positions of the coating bar. The wire diameter is increased at the end portions and decreased at the center portion, creating localized differences in coating thickness. This allows the ends to have thicker coating layers for improved adhesion while the center maintains appropriate thickness, directly resolving the contradiction between uniform structure simplicity and localized adhesion strength requirements.
Solution Approach 2:
The patent changes the geometric parameter of the wire diameter along the length of the coating bar. By systematically varying the wire diameter from the center to the ends, the coating bar produces non-uniform coating thickness distribution. This parameter change enables thicker coating at the ends to improve adhesive strength without requiring a completely different coating mechanism, thus resolving the contradiction between structural simplicity and adhesion performance.
2Strength
If the coating layer thickness is increased at the ends, then adhesive strength is improved, but the coating process becomes more complex
Solution Approach 1:
The patent implements local quality by modifying only specific portions of the coating bar (the wire diameters at ends and center) rather than redesigning the entire coating system. This localized modification approach allows the ends to have enhanced coating thickness for better adhesion while keeping the overall manufacturing process relatively simple, thus resolving the contradiction between improved adhesion and manufacturing complexity.
3Reliability
If a standard coating bar is used, then manufacturing is simple, but adhesion failure occurs at the ends due to insufficient coating thickness
Solution Approach 1:
The patent addresses adhesion reliability by applying local quality enhancement at the critical end portions where adhesion failure typically occurs. By increasing the wire diameter at the ends, the coating thickness is locally increased to prevent adhesion failure, while the overall coating bar design remains relatively simple. This resolves the contradiction between using a standard simple coating bar and ensuring reliable adhesion at all positions.
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 ensures uniform adhesive strength across the entire interface by forming a thicker coating layer at the ends, preventing adhesion failure and maintaining battery performance.
Implementation Method 1
the coating bar includes a cylindrical bar and a wire wound on the cylindrical bar, the cylindrical bar has a smaller diameter at two ends than a diameter at a center
Data Source
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AI summary
The present disclosure relates to a coating bar and a method for manufacturing a separator using the same. The coating bar according to the present disclosure may form a coating layer having an area with different thicknesses by one coating. Additionally, the method for manufacturing a separator according to the present disclosure includes forming a porous coating layer using a predetermined coating bar, to manufacture a separator including the porous coating layer having an area with different thicknesses. In particular, the present disclosure manufactures the separator having a larger thickness at the two ends than at the center, thereby avoiding a lack of adhesive strength at the two ends in a transverse direction in the adhesion between the separator and the electrode, and exhibiting uniform adhesive strength over the whole interface between the separator and the electrode.