Battery Electrode Coating With Masked Edges for Uniform End Portions
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Solution Overview
Problem
Existing methods for preparing electrodes in lithium secondary batteries face challenges in uniformly forming the end portions of active material layers, leading to issues like sliding and mismatching portions, which reduce battery capacity and efficiency.
Innovation Solution
A method involving dividing the current collector surface into active material-laminated and non-laminated portions, attaching masking tape to the non-laminated portion, laminating the active material layer, forming a cutting groove along the masking tape boundary, and removing the tape to create a right-angled corner portion where the active material layer meets the side wall surface, ensuring a uniform and increased battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active material slurry is applied on the current collector using conventional coating methods, then the coating process can be completed, but drag lines and island formations occur making it difficult to form a uniform surface at the end portion of the active material layer
Solution Approach 1:
A masking tape is attached to the current collector before applying the active material slurry. This preliminary action defines the coating boundary and prevents slurry from reaching the edge, thereby avoiding drag lines and island formations while maintaining uniform surface quality at the end portion of the active material layer.
2Quantity of substance
If the active material layer is coated to maximize capacity, then the battery capacity increases, but sliding portions with gradually decreasing thickness are formed at the edge reducing the effective capacity
Solution Approach 1:
The masking tape is attached in advance to define the precise coating boundary. This allows the active material layer to be coated with uniform thickness up to the masking tape boundary, preventing the formation of sliding portions with gradually decreasing thickness at the edge, thereby maximizing effective capacity.
3Quantity of substance
If slurry is applied on both surfaces of the current collector to increase capacity, then the battery capacity increases, but mismatching occurs between the positions of slurry on upper and lower surfaces causing dislocation and reducing charge-discharge efficiency
Solution Approach 1:
Masking tapes are attached to both surfaces of the current collector before slurry application. These masking tapes serve as alignment guides that ensure the slurry on upper and lower surfaces is positioned precisely, preventing mismatching and dislocation, thereby maintaining high charge-discharge efficiency while maximizing capacity.
4Ease of manufacture
If the active material layer edge is formed with conventional methods, then the coating process is simple, but corner portions where upper surface and side wall surface meet are not formed in a right-angled shape reducing battery performance
Solution Approach 1:
The masking tape is attached vertically at the edge of the current collector before slurry coating. This preliminary action creates a right-angled boundary that guides the slurry formation, ensuring that corner portions where the upper surface and side wall surface meet are formed in a precise right-angled shape, thereby improving battery performance while maintaining process simplicity.
Data Source
AI summary
A method for preparing an electrode, includes (a) designating a current collector surface into an active material layer-laminated portion and an active material-nonlaminated portion, and attaching a masking tape to the active material-nonlaminated portion; (b) laminating an active material layer on the masking tape-attached current collector; (c) forming a cutting groove on an upper surface of the active material layer along a boundary of the masking tape at the bottom and the active material; and (d) removing the masking tape along the cutting groove to form the active material-nonlaminated portion, and an electrode in which a corner portion where an upper surface of the active material layer and a side wall surface forming a thickness of the active material layer meet is formed in a right-angled shape.