Battery Electrode Binder Layering for Adhesion
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Solution Overview
Problem
The existing methods for producing battery electrodes result in decreased adhesive strength between the current collector and the electrode active material layer due to binder migration during the drying process, leading to poor battery performance.
Innovation Solution
A method is developed where a binder solution layer is applied to the current collector before coating the compound material paste, allowing the binder to concentrate at the interface during drying, enhancing adhesion and maintaining electrical conductivity by forming a binder solution layer with a non-coated region, which secures an electrically conductive path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a compound material paste containing binder and active material is coated onto current collector and dried, then the electrode structure is formed, but binder migrates to surface layer during drying causing decreased adhesive strength between current collector and compound material layer
Solution Approach 1:
The patent applies preliminary action by coating the binder solution onto the current collector before applying the compound material paste. This preliminary binding layer is formed in advance to prevent binder migration during subsequent drying, ensuring the binder remains concentrated at the interface between the current collector and compound material layer, thereby maintaining high adhesive strength.
2Strength
If binder solution layer is applied to current collector before compound material paste, then adhesive strength is enhanced, but additional process step is required
Solution Approach 1:
The patent merges the binder application step with the compound material paste coating step by applying the binder solution first, then immediately applying the compound material paste over it. This combination approach integrates two functions (binder application and active material application) into a sequential coating process, enhancing adhesive strength while maintaining process efficiency without requiring separate binder coating equipment.
3Strength
If binder solution layer is applied to current collector, then adhesive strength is improved, but electrical conductivity may be affected
Solution Approach 1:
The patent applies local quality by creating a binder solution layer with controlled coverage that provides different functions in different regions. The binder solution is applied to specific areas of the current collector where adhesion is needed, while leaving other areas exposed or partially covered to maintain electrical conductivity pathways. This localized application ensures high adhesive strength at the interface without compromising the overall electrical conductivity of the electrode structure.
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 method significantly improves the adhesive strength and electrical conductivity between the current collector and the compound material layer, resulting in batteries with high cycle durability, superior output characteristics, and enhanced productivity.
Implementation Method 1
convection occurs during drying, and since binder in the vicinity of the current collector gathers (rises up) in the surface layer portion
Implementation Method 2
drying by passing through a hot air dryer and the like to form a layer containing the negative electrode active material
Data Source
Figure 1~2
Figure 3~5
Figure 6A~6B
AI summary
According to the present invention, formation of a compound material layer is carried out by a method that includes a step of forming a binder solution layer 56 by applying a binder solution 50 containing a binder 54 to a current collector 10, a step of depositing the binder solution layer 56 and a compound material paste layer 46 on the current collector 10 by applying a compound material paste 40 over the binder solution layer 56, and a step of obtaining an electrode in which the compound material layer is formed on the current collector 10 by drying both the binder solution layer 56 and the compound material paste layer 46. Here, the binder solution 56 has a binder solution non-coated region 58 where a surface 12 of the current collector 10 is exposed, and the drying is carried out in a state in which a portion of the compound material paste layer 46 is deposited on the current collector 10 in the binder solution non-coated region 58.