Patterned Binder Layer for Lithium-Ion Battery Peel Strength
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in maintaining high peel strength between the current collecting foil and electrode material while reducing penetration resistance, as adhesive layers with high insulating properties increase internal resistance, and thinning the adhesive layer to reduce resistance leads to peeling issues.
Innovation Solution
A lithium ion secondary battery design featuring a current collecting foil with a patterned binder layer, where binder-coated sections and uncoated sections are alternately formed, allowing for enhanced peel strength through binder bonding and direct contact between the foil and electrode material, reducing penetration resistance by creating conductive paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive layer is formed on the current collecting foil to ensure peel strength, then the bond between foil and electrode material is improved, but the internal resistance (penetration resistance) increases due to the insulating binder
Solution Approach 1:
The adhesive layer is segmented into patterned regions rather than forming a continuous layer. The current collecting foil surface is divided into adhesive regions (with binder) and non-adhesive regions (without binder), creating a segmented structure that provides both bonding areas and conductive paths, thus resolving the contradiction between peel strength and internal resistance
Solution Approach 2:
Different regions of the current collecting foil are given different local qualities: some regions have adhesive properties (with binder) for strong bonding, while other regions have conductive properties (without binder) for low resistance. This local differentiation allows simultaneous achievement of high peel strength and low internal resistance
2Loss of energy
If the adhesive layer is thinned to reduce penetration resistance, then the internal resistance is reduced, but the peel strength decreases and electrode material peels off
Solution Approach 1:
Instead of uniformly thinning the adhesive layer, the invention segments the adhesive coverage area. The adhesive layer exists only in patterned regions rather than covering the entire foil surface, allowing sufficient bond strength in adhesive regions while providing extensive conductive paths in non-adhesive regions, thus achieving low penetration resistance without sacrificing peel strength
Solution Approach 2:
The binder material is extracted from certain regions of the current collecting foil surface, creating non-adhesive regions. This removal of binder in specific areas provides direct conductive paths between foil and electrode material, reducing penetration resistance while the remaining adhesive regions maintain sufficient peel strength
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 battery achieves high peel strength and reduced penetration resistance, improving low-temperature reaction performance and overall efficiency by ensuring stable distribution of the binder-coated and uncoated sections on the current collecting foil.
Implementation Method 1
a binder layer is formed in a pattern design on the current collecting foil... the mixture layer is formed on the binder coated section... ensuring a certain level of peel strength
Data Source
AI summary
A lithium-ion secondary battery has an electrode sheet having a current collecting foil formed thereon with a mixture layer containing powdered mixture particles. On the current collecting foil, there are provided a binder coated section on which a binder layer is formed having patterned markings; and a binder non-coated section on which a binder layer is not formed. The mixture particles contain at least an electrode active material and a binder. The mixture layer is formed on the binder coated section and the binder non-coated section.