Carbon Nanotube Current Collectors for Thin Film Li-Ion Batteries
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Solution Overview
Problem
Thin film lithium ion batteries face challenges with low power density and short lifespan due to the use of heavy metal foils for current collectors, which are also prone to corrosion by the electrolyte.
Innovation Solution
The use of carbon nanotube layers as current collectors, which provide high conductivity, stability, and low weight, reducing corrosion and increasing the lifespan of the battery, while maintaining high power density.
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 parameter of the current collector from traditional metal foils to carbon-based materials (graphene, carbon nanotubes, carbon fibers). This material substitution fundamentally alters the weight-to-conductivity ratio, achieving high electrical conductivity with significantly reduced weight, thereby increasing power density.
Solution Approach 2:
The patent employs composite carbon-based structures (graphene-carbon nanotube composites, carbon fiber networks) that combine multiple carbon materials to achieve optimal balance between electrical conductivity, mechanical strength, and weight. These composite structures provide superior performance compared to single-material approaches.
2Reliability
If metal foils are used as current collectors, then electrical conductivity is achieved, but corrosion by electrolyte occurs and lifespan decreases
Solution Approach 1:
The patent changes the chemical composition parameter of the current collector from reactive metals to chemically inert carbon-based materials. Carbon materials exhibit exceptional resistance to electrolyte corrosion, eliminating the degradation and failure modes associated with metal foils, thereby extending battery lifespan and improving reliability.
Solution Approach 2:
The patent replaces expensive, corrosion-prone metal foils with cost-effective carbon-based materials that offer long-term durability. The carbon-based current collectors maintain structural integrity and electrical performance over extended periods, eliminating the need for frequent replacement due to corrosion.
3Power
If carbon nanotube layers are used as current collectors, then weight is reduced and power density increases, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary preparation of carbon-based materials through controlled synthesis methods (chemical vapor deposition, arc discharge) to create pre-formed graphene sheets, carbon nanotube bundles, or carbon fiber mats. These pre-prepared materials can be directly integrated into battery assembly processes, reducing on-site manufacturing complexity while maintaining high power density benefits.
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 carbon nanotube layers enhance the power density and extend the lifespan of thin film lithium ion batteries by offering superior conductivity and chemical stability without the weight and corrosion issues associated with metal foils.
Implementation Method 1
The carbon nanotube layers enhance the power density and extend the lifespan of thin film lithium ion batteries by offering superior conductivity
Data Source
AI summary
A method for making a thin film lithium ion battery is provided. A cathode material layer and an anode material layer are provided. A carbon nanotube array is applied to a surface of the cathode material layer and pressed to form a first carbon nanotube layer on the surface of the cathode material layer to obtain a cathode electrode. A second carbon nanotube layer is formed on a surface of the anode material layer to obtain an anode electrode. A solid electrolyte layer is applied between the cathode electrode and the anode electrode to form a battery cell. At least one battery cell is then encapsulated in an external encapsulating shell.