Gradient Negative Electrode Plate for Fast-Charging Energy Density
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Solution Overview
Problem
Lithium-ion batteries face challenges in increasing energy density and charging capability due to the limitations of electrode plate thickness and compaction density, which affect lithium ion migration and porosity, leading to poor battery performance.
Innovation Solution
A negative electrode plate design featuring a current collector with an active layer containing a silicon-based or metal oxide/material sulfide functional material, where the material content increases away from the collector, forming a concentration gradient, enhancing porosity and mass transfer while maintaining energy density and reducing electrical contact loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the electrode plate is increased to improve energy density, then the energy density is improved, but the migration distance of lithium-ion is increased leading to decreased charging capability
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of functional materials within the active layer. Specifically, the first functional material (silicon-based, metal oxide, or metal sulfide) is concentrated in regions farther from the current collector, while the second functional material (conductive agent) is concentrated in regions closer to the current collector. This spatial differentiation optimizes both energy storage (through high-capacity materials) and charge transport (through conductive materials), resolving the contradiction between energy density and charging capability.
2Quantity of substance
If the compaction density of the electrode plate is increased to improve energy density, then the energy density is improved, but the porosity of the electrode plate decreases leading to decreased charging capability
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially differentiated material distribution. The active layer contains regions with different functional material concentrations: areas closer to the current collector have higher conductive agent content for electron transport, while areas farther away have higher active material content for lithium ion insertion/extraction. This localized optimization allows high compaction density without uniformly reducing porosity, maintaining charging capability while improving energy density.
Solution Approach 2:
The patent employs composite materials by combining two distinct functional materials in the active layer: a first functional material (silicon-based, metal oxide, or metal sulfide) with high lithium ion insertion/extraction capacity, and a second functional material (conductive agent) with high electrical conductivity. This composite structure allows the electrode to simultaneously achieve high energy density through the active material and high charging capability through the conductive material network, even at high compaction densities.
3Quantity of substance
If high capacity functional materials are used to improve energy density, then energy density is improved, but electrical contact loss occurs leading to decreased performance
Solution Approach 1:
The patent applies local quality by strategically distributing different functional materials in different regions of the active layer. The second functional material (conductive agent) is concentrated in regions closer to the current collector where electrical contact is critical, ensuring low resistance and stable electrical connection. The first functional material (high capacity material) is concentrated in regions farther from the collector where energy storage is prioritized. This spatial differentiation maintains electrical contact while maximizing energy density.
Solution Approach 2:
The patent uses composite materials by creating an active layer that combines a first functional material (silicon-based, metal oxide, or metal sulfide) with high lithium ion capacity and a second functional material (conductive agent) with high electrical conductivity. This composite structure ensures that high capacity materials are paired with sufficient conductive material to maintain electrical contact, resolving the contradiction between energy density and electrical contact stability.
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 design improves lithium ion migration and energy density, enhances fast charging performance, and maintains energy density by increasing porosity and conductivity, thereby addressing the limitations of previous battery technologies.
Implementation Method 1
the first functional material includes at least one of a silicon-based material, a metal oxide, or a metal sulfide... having a greater expansion rate
Implementation Method 2
the migration distance of the lithium-ion is increased due to the increase of the thickness of the electrode plate
Implementation Method 3
the content of the first functional material increases in a direction away from the current collector... enhancing the mass transfer capability of the active layer
Data Source
AI summary
Disclosed are a negative electrode plate and a battery, the negative electrode plate includes a current collector and an active layer; the active layer is positioned on two opposite surfaces of the current collector; the active layer includes a first functional material; the content of the first functional material increases in a direction away from the current collector; the content of the first functional material in a first region of the active layer is less than the content of the first functional material in a second region of the active layer; the vertical distance from the first region to the current collector is less than the vertical distance from the second region to the current collector; and the first functional material includes at least one of a silicon-based material, a metal oxide, or a metal sulfide. The energy density and dynamics of the negative electrode plate are improved.