Electrode Binder Layer Layout for Notching-Induced Active Material Loss
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Solution Overview
Problem
The manufacturing process of electrodes in secondary batteries leads to deintercalation of electrode active material due to reduced binder content for higher energy density, which results in low voltage issues and performance deterioration.
Innovation Solution
A binder layer is formed between the current collector and the electrode active material layer, specifically at both ends, comprising 60 to 90 wt% binder and 10 to 40 wt% conductive material, with a thickness ratio of 1 to 30% of the electrode active material layer and width ratio of 5 to 20% in the coating direction, preventing deintercalation during notching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If binder content is increased to prevent deintercalation, then adhesion is improved, but energy density decreases
Solution Approach 1:
The binder layer is applied selectively only at both ends of the electrode active material layer, rather than uniformly across the entire surface. This localized application provides enhanced adhesion where deintercalation occurs during notching, while preserving energy density by minimizing binder content in the central active material region.
Solution Approach 2:
The binder layer is divided into discrete segments positioned at the two ends of the electrode, separated by the active material layer in the middle. This segmentation allows the binder to perform its adhesion function at critical locations without compromising the overall energy density of the electrode.
2Ease of operation
If notching is performed to prepare electrode tabs, then ease of operation is improved, but deintercalation of active material occurs
Solution Approach 1:
The binder layer is applied to the current collector at both ends before the electrode slurry is coated. This preliminary action ensures that the binder is already in position to prevent deintercalation when notching is subsequently performed to create electrode tabs, thus protecting the active material during the cutting process.
Solution Approach 2:
The binder layer acts as a protective cushion or barrier layer at the ends of the electrode before notching occurs. This beforehand cushioning prevents the active material from deintercalating during the mechanical stress of the notching process, thereby reducing active material loss.
3Reliability
If binder moves to surface during drying, then adhesion is enhanced, but deintercalation increases
Solution Approach 1:
The binder is concentrated at the end regions of the electrode where it can move to the surface during drying to enhance adhesion, without affecting the central active material layer. This localized quality control allows beneficial binder migration at specific locations while preventing harmful deintercalation in the active material region.
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 binder layer enhances adhesion and conductivity, preventing active material loss and maintaining battery performance by minimizing deintercalation and ensuring consistent electrode capacity.
Implementation Method 1
a binder layer is formed between the current collector and the electrode active material layer
Implementation Method 2
the binder layer includes 60 to 90 wt % of binder and 10 to 40 wt % of conductive material
Data Source
AI summary
The present invention relates to an electrode capable of preventing detachment of an active material during a notching process and a process of using the electrode, and to a method for manufacturing same, wherein the electrode has a structure in which an electrode active material layer is formed on a current collector having an electrode tab formed at one end thereof, and a binder layer is formed between the current collector and the electrode active material layer, wherein the binder layer is formed at both ends of the current collector.