Nonaqueous Battery Electrode Porous Inorganic Layer
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high input-output performance due to excessive seepage of binder into the active material layer, which affects their reliability and efficiency, particularly in vehicular applications where high performance is critical.
Innovation Solution
A method for manufacturing a nonaqueous secondary battery electrode with a porous inorganic layer by adjusting the water concentration of the active material layer to 100 ppm to 500 ppm and coating a slurry containing inorganic particles and a binder, thereby controlling the seepage of the solvent and binder into the active material layer, and using alumina particles as preferred inorganic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slurry containing binder and organic solvent is coated on the active material layer to form a porous inorganic layer, then the reliability of the battery is improved by preventing internal short-circuits, but the input-output performance deteriorates due to excessive seepage of binder into the active material layer
Solution Approach 1:
The invention changes the water concentration parameter of the active material layer surface to a specific range (50-500 ppm) before coating. This parameter adjustment controls the seepage behavior of the organic solvent and binder during the coating process, allowing the binder to be restrained from excessively penetrating into the active material layer while still forming a protective porous inorganic layer on the surface.
Solution Approach 2:
Water acts as an intermediary substance in this invention. By controlling the water concentration on the active material layer surface, it mediates between the binder and the active material layer, preventing direct excessive contact and penetration of the binder into the active material particles, thus resolving the contradiction between forming a protective layer and maintaining input-output performance.
2Reliability
If the binder is dispersed in liquid medium and coated on the active material layer surface, then the porous inorganic layer is formed effectively, but the input-output performance is reduced due to binder covering the active material particles
Solution Approach 1:
The invention adjusts the water concentration parameter of the active material layer surface to a specific range (50-500 ppm) before coating. This parameter adjustment controls the seepage behavior of the organic solvent and binder during the coating process, allowing the binder to be restrained from excessively penetrating into the active material layer while still forming a protective porous inorganic layer on the surface.
Solution Approach 2:
The invention applies local quality control by creating a specific water concentration environment only on the surface of the active material layer where the coating will be applied. This localized water concentration control ensures that the binder behaves differently at the surface compared to the bulk, allowing protective layer formation while maintaining the internal quality and performance of the active material particles.
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 approach results in a highly reliable and high-performance battery with improved adhesiveness and reduced internal resistance, suitable for use as a power source in vehicles, by forming a porous inorganic layer with controlled seepage and enhanced peeling strength.
Implementation Method 1
adjusting a water concentration of the active material layer so that a water concentration of at least the surface of the active material layer is 100 ppm to 500 ppm
Data Source
AI summary
A method is provided for manufacturing an electrode that has a porous inorganic layer on the surface of an active material layer and is suitable for constructing a nonaqueous secondary battery with excellent input-output performance. In this manufacturing method, an electrode perform, which has an active material layer (344) consisting primarily of active material particles (42) and supported on a collector (342), is prepared. The water concentration of at least the surface (344a) of the active material layer (344) is adjusted to 100 ppm to 500 ppm. A slurry (S) containing inorganic particles (44), a binder and an organic solvent is coated on the surface (344a) of the active material layer with the water concentration thus adjusted, to form a porous inorganic layer.