Positive Electrode Coating Layout for Internal Short Prevention
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Solution Overview
Problem
Secondary batteries with stack-type electrode assemblies are prone to internal short circuits due to contact between positive and negative electrodes through the separator, especially under abnormal conditions, which affects safety and cycle life.
Innovation Solution
A system and method for manufacturing a positive electrode involving an unwinder, a first coating unit to apply an insulating material at predetermined positions, a first drying furnace to dry the insulating material, a second coating unit to apply a positive electrode slurry between insulating portions, and a second drying furnace to form a positive electrode film, using a gravure roll for precise control of the insulating portion and a slot die coater for uniform slurry application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating portion is formed on the positive electrode to prevent contact with the negative electrode, then safety is improved, but manufacturing precision is required which increases device complexity
Solution Approach 1:
The insulating material is coated on the positive electrode base material before the electrode slurry is applied. This preliminary action ensures that the insulating portion is already in place to prevent contact between the positive electrode and negative electrode, thereby improving safety without requiring complex post-manufacturing adjustments
Solution Approach 2:
The positive electrode is segmented into different functional regions: the insulating portion coated on the base material and the electrode portion formed by the slurry. This segmentation allows the insulating material to be precisely positioned in specific areas to prevent short circuits while maintaining simplicity in the overall manufacturing process
2Reliability
If the insulating material is coated at predetermined positions with high precision, then internal short circuit risk is reduced, but manufacturing time increases
Solution Approach 1:
The insulating material is coated on the positive electrode base material before the electrode slurry is applied. This preliminary action ensures that the insulating portion is already in place to prevent contact between the positive electrode and negative electrode, thereby improving safety without requiring complex post-manufacturing adjustments
Solution Approach 2:
The coating process is performed continuously on the positive electrode base material as it passes through the coating unit, rather than requiring discrete stopping and positioning operations. This continuous process reduces manufacturing time while maintaining precision in the placement of the insulating material
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
Prevents mixing of insulating material and positive electrode slurry, ensuring precise formation of insulating and electrode portions, thereby reducing the risk of internal short circuits and enhancing the safety and longevity of secondary batteries.
Implementation Method 1
a first drying furnace configured to dry the insulating material by heating the positive electrode base material coated with the insulating material
Implementation Method 2
a second drying furnace configured to heat and dry the positive electrode base material coated with the insulating material and the positive electrode slurry
Data Source
AI summary
A method for manufacturing a positive electrode for a secondary battery includes unwinding a positive electrode base material, transferring the positive electrode base material to a first coating unit through a plurality of rollers, coating an insulating material at predetermined positions on opposite sides of the positive electrode base material with respect to a transfer direction of the positive electrode base material to form insulating portions, drying the insulating material to form insulating portions, coating a positive electrode slurry between the insulating portions on the opposite sides of the positive electrode base material, and drying the positive electrode slurry to form a positive electrode film formed with a positive electrode portion on the positive electrode base material.