Nonaqueous Battery Electrode Pore Distribution for Li-Ion Transport
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Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges in achieving excellent output performance due to issues with the dispersion and aggregation of conductive assistants, leading to poor Li ion diffusion and decreased electrical conductivity.
Innovation Solution
The electrode mixture layer is designed with a specific pore volume distribution ratio and the use of a combination of carbon materials with different particle sizes to ensure uniform dispersion and prevent aggregation, enhancing Li ion diffusion and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive assistant is added to improve electrical conductivity, then electrical conductivity is improved, but aggregation occurs leading to poor Li ion diffusion
Solution Approach 1:
The patent controls the pore volume distribution parameters (P1/P2 ratio and S1/S2 ratio) to specific ranges to optimize the dispersion state of conductive assistant. By adjusting these pore structure parameters, the patent achieves uniform distribution of conductive assistant particles without aggregation, thereby maintaining high electrical conductivity while enabling smooth Li ion diffusion pathways.
Solution Approach 2:
The patent utilizes a porous electrode mixture layer with specifically controlled pore volume distribution. The porous structure provides spaces that prevent aggregation of conductive assistant particles while maintaining electrical conductivity. The pore size distribution (with P1 representing maximum differential pore volume and P2 representing pore volume at 0.03 μm) is optimized to balance conductive assistant dispersion and Li ion diffusion.
2Quantity of substance
If pore diameter is reduced to increase density, then energy density is improved, but Li ion diffusion is inhibited
Solution Approach 1:
The patent optimizes the pore volume distribution parameters (P1, P2, S1, S2) to achieve a balanced pore structure. By controlling the P1/P2 ratio to be 2 or more and the S1/S2 ratio to be 3 or more and less than 10, the patent creates a pore size distribution that allows sufficient Li ion diffusion while maintaining high enough density for good energy density.
Solution Approach 2:
The patent creates different pore size regions within the electrode mixture layer. Larger pores (represented by P1) provide diffusion pathways for Li ions, while smaller pores (represented by P2) contribute to density. This local differentiation of pore sizes allows the structure to simultaneously satisfy both Li ion diffusion requirements and energy density requirements.
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 solution results in improved output performance by ensuring sufficient dispersion of conductive assistants, reducing small pore diameters that inhibit Li ion diffusion, and maintaining high crystallinity of the carbon materials, thereby enhancing the battery's energy density and cycling characteristics.
Implementation Method 1
enhancing Li ion diffusion
Implementation Method 2
enhancing the battery's energy density and cycling characteristics
Data Source
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AI summary
An electrode according to an embodiment contains an electrode mixture layer containing an active material and a conductive assistant. In a logarithmic differential pore volume distribution by a mercury intrusion method, the electrode mixture layer satisfies: a ratio P1/P2 within a range of 2 or more and less than 8, and a ratio S1/S2 within a range of 3 or more and less than 10. P1 is a value of a maximum logarithmic differential pore volume in a pore diameter range of 0.1 µm or more and 1 µm or less. P2 is a value of a logarithmic differential pore volume of a pore diameter of 0.03 µm. S1 is an integrated value in a pore diameter range of 0.1 µm or more and 1 µm or less. S2 is an integrated value in a pore diameter range of more than 0 µm and less than 0.1 µm.