Negative Electrode Tortuosity for Faster Electrolyte Wetting
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Solution Overview
Problem
Existing lithium-ion battery technologies face challenges in achieving low-temperature discharge performance and efficient production due to lengthy electrolyte wetting processes, which affect cost and performance requirements, especially for electric vehicles and tools.
Innovation Solution
The electrochemical apparatus features a negative electrode plate with a tortuosity of the electrolyte transmission path limited to 1 ≤ T ≤ 2.5, achieved by controlling compacted density, porosity, and particle size distribution, along with the inclusion of specific materials like artificial or natural graphite and a sulfur-oxygen double bond compound in the electrolyte, to enhance wettability and low-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is left at room temperature and high temperature for electrolyte wetting, then the electrolyte wettability is improved, but the production time cycle is significantly extended
Solution Approach 1:
The patent changes the physical parameters of the negative electrode active material layer, specifically controlling the tortuosity factor to be 1.3 ≤ T < 2.0, compacted density to be 1.45 g/cm³ ≤ PD < 1.75 g/cm³, and porosity to be 30% ≤ ε < 45%. These parameter optimizations enable the electrolyte to penetrate the electrode structure more efficiently, achieving good wettability without requiring extended soaking times at elevated temperatures, thus reducing the production time cycle while maintaining reliable electrolyte distribution.
2Reliability
If the tortuosity of the negative electrode active material layer is reduced, then the electrolyte transmission path is shortened and wettability is improved, but the structural complexity of the electrode increases
Solution Approach 1:
The patent optimizes the tortuosity factor T to a specific range (1.3 ≤ T < 2.0) by adjusting the compacted density PD (1.45 g/cm³ ≤ PD < 1.75 g/cm³) and porosity ε (30% ≤ ε < 45%) of the negative electrode active material layer. This parameter control approach achieves improved electrolyte wettability and shortened transmission paths without requiring complex structural modifications, as the tortuosity is controlled through the inherent packing and pore structure of the active material particles themselves rather than through additional structural elements.
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 significantly reduces the standing time after electrolyte injection, improves low-temperature discharge performance, and balances energy density, ensuring faster production and enhanced battery efficiency.
Implementation Method 1
a tortuosity T of the negative electrode active material layer satisfies the following relation: 1
Data Source
AI summary
An electrochemical apparatus includes an electrolyte and a negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The negative electrode active material layer contains a negative electrode active material, and a tortuosity T of the negative electrode active material layer satisfies the following relation: 1 < T ≤ 2.5, where the tortuosity T is a ratio of a transmission path length Lt of the electrolyte in pores of the negative electrode active material layer to a thickness L0 of the negative electrode active material layer.