Negative Electrode Sheet Orientation for High-Rate Battery Capacity
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Solution Overview
Problem
Non-aqueous secondary batteries with existing negative electrode materials struggle to achieve excellent rate characteristics due to limitations in the orientation and density of particulate carbon and silicon active materials in the negative electrode mixed material layer.
Innovation Solution
A negative electrode material sheet with a particulate carbon material having a specific diffraction intensity ratio and low resin content, combined with controlled orientation and density, is used to enhance the rate characteristics of non-aqueous secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon active material is used to increase battery capacity, then the theoretical capacity of the secondary battery increases, but the interelectrode distance is increased due to expansion and shrinkage
Solution Approach 1:
The particulate carbon material acts as an intermediary framework that mediates between the silicon active material and the electrode structure. It provides a stable conductive network that accommodates silicon's volume changes during charging/discharging, preventing direct transmission of expansion forces to the current collector and maintaining consistent interelectrode distance while preserving high capacity.
Solution Approach 2:
The oriented particulate carbon material forms a flexible, porous framework structure that can dynamically adapt to silicon's expansion and shrinkage. This carbon matrix acts as a flexible containment structure that maintains electrode integrity and spacing throughout the charging/discharging cycle, allowing high silicon content without increasing interelectrode distance.
2Quantity of substance
If the negative electrode mixed material layer is optimized for capacity, then the battery capacity increases, but the rate characteristics remain insufficient
Solution Approach 1:
The patent transitions from conventional two-dimensional planar orientation (parallel to current collector) to three-dimensional angular orientation (45°-90° relative to current collector). This dimensional change in spatial arrangement creates more diverse ion transport pathways and improves electrolyte penetration, simultaneously enhancing both capacity utilization and rate characteristics by optimizing the electrode's internal architecture.
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 proposed solution significantly improves the rate characteristics of non-aqueous secondary batteries by optimizing the orientation and density of the negative electrode material sheet, leading to increased capacity and reduced interelectrode distance changes during charging and discharging.
Implementation Method 1
a paste containing a particle carbon material and a silicon active material is applied on a current collector, and a magnetic field is applied to the applied paste, whereby the particulate carbon material is oriented in a predetermined direction
Data Source
AI summary
The purpose of the present invention is to provide a negative electrode material sheet for a non-aqueous secondary cell, the negative electrode material sheet being capable of forming a negative electrode that can exhibit exceptional rate characteristics in a non-aqueous secondary cell. This negative electrode material sheet for a non-aqueous secondary cell is characterized by containing a particulate carbon material, and moreover is characterized in that the ratio I(110)/I(004) of the diffraction intensity of the (110) plane with respect to the diffraction intensity of the (004) plane in X-ray diffraction of a main surface is 1.1 or greater, and at least one of (1) the resin content being 8 mass % or less and (2) the density being 1.3 g/cm3 or less is satisfied.