Carbon Nanotube Graphene Current Collectors for Li-Ion Batteries
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Solution Overview
Problem
Lithium ion batteries face challenges with low power density and short lifespan due to the weight and corrosion of traditional metal foils used for current collectors.
Innovation Solution
The use of carbon nanotube and graphene layers as current collectors, which provide high conductivity, stability, and low weight, replacing traditional metal foils to enhance power density and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If metal foils are used as current collectors, then electrical conductivity is achieved, but weight increases and power density decreases
Solution Approach 1:
The patent changes the material parameters of the current collector from traditional metal foils to carbon-based materials (carbon nanotubes and graphene). This material substitution fundamentally alters the weight-to-conductivity ratio, achieving lower weight while maintaining or improving electrical conductivity, thereby increasing power density.
Solution Approach 2:
The patent employs composite structures combining carbon nanotubes and graphene in the current collector. These composite carbon materials provide both mechanical strength and excellent electrical conductivity with significantly reduced weight compared to metal foils, resolving the contradiction between conductivity and weight.
2Reliability
If metal foils are used as current collectors, then electrical conductivity is provided, but corrosion occurs and lifespan decreases
Solution Approach 1:
The patent changes the chemical composition of the current collector from metal-based to carbon-based materials. Carbon materials inherently possess superior chemical stability and immunity to electrolyte corrosion, eliminating the corrosion problem that limits metal foil lifespan while maintaining electrical conductivity.
Solution Approach 2:
The patent replaces expensive, corrosion-prone metal foils with more stable carbon-based materials that do not degrade in the electrolyte environment. This substitution eliminates the need for protective coatings and extends the operational life of the battery by preventing current collector degradation.
3Power
If carbon nanotube and graphene layers are used as current collectors, then weight is reduced and power density increases, but manufacturing complexity increases
Solution Approach 1:
The patent divides the current collector into distinct functional layers: carbon nanotube layers and graphene layers. Each layer provides specific functions (carbon nanotubes for structural framework and conductivity, graphene for surface conductivity and stability), allowing optimization of each component while managing overall complexity through clear functional segmentation.
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 lithium ion batteries exhibit improved power density and extended lifespan with the carbon nanotube and graphene layers, which offer stable chemical and electrical stability while reducing weight.
Implementation Method 1
The cathode current collector includes a graphene layer and a carbon nanotube layer stacked with each other
Data Source
AI summary
A method for making lithium ion battery is provided. A cathode material layer and an anode material layer are provided. A cathode current collector is formed on a surface of the cathode material layer to obtain a cathode electrode. The cathode current collector includes a graphene layer and a carbon nanotube layer stacked with the graphene layer. An anode current collector is formed on a surface of the anode material layer to obtain an anode electrode. A separator is applied between the cathode electrode and the anode electrode thereby forming a battery cell. At least one battery cell is encapsulated in an external encapsulating shell. An electrolyte solution is injected into the external encapsulating shell.