Composite Anode via Electrophoretic Deposition for Silicon Expansion
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Solution Overview
Problem
Current lithium-ion batteries using silicon anodes face challenges due to low electronic conductivity and significant volume expansion during charging, while silicon-carbon composite anodes manufactured with high-cost and complex methods like CVD are impractical for large-scale production.
Innovation Solution
A composite anode is developed using a copper current collector with a combination of carbon and silicon, deposited via an electrophoretic deposition method, which includes a conductive agent like polyacrylonitrile or carbon black, and silicon in forms such as powder or nanowires, offering a cost-effective and scalable solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon anode is used to increase energy density, then energy density is improved, but electronic conductivity deteriorates and volume expansion increases
Solution Approach 1:
The patent applies composite materials by combining silicon particles with carbon matrix to create silicon-carbon composite anodes. This composite structure allows the silicon to provide high energy density while the carbon matrix provides electronic conductivity pathways and accommodates volume expansion, thus resolving the contradiction between energy density improvement and conductivity deterioration.
Solution Approach 2:
The patent uses carbon coating as a flexible shell around silicon particles. This thin film structure allows the silicon core to expand and contract during charging-discharging cycles while maintaining structural integrity and electrical conductivity through the carbon layer, addressing both the conductivity issue and volume expansion problem.
2Use of energy by moving object
If silicon anode is used to increase energy density, then energy density is improved, but volume expansion increases
Solution Approach 1:
The carbon coating acts as a flexible shell that can accommodate the volume expansion of silicon during lithium insertion. The carbon matrix provides a buffer zone that absorbs expansion stress, preventing structural collapse while allowing the silicon to achieve its high energy density potential.
Solution Approach 2:
The silicon-carbon composite structure distributes the volume expansion stress across the entire composite material rather than concentrating it in the silicon phase alone. The carbon matrix acts as a stress-distributing network that mitigates the harmful effects of silicon expansion.
3Manufacturing precision
If CVD method is used to manufacture silicon-carbon composite, then composite quality is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent replaces expensive CVD equipment and processes with simpler, cheaper alternative methods such as mechanical mixing, spray drying, or freeze drying. These alternative methods use inexpensive equipment that is already available in most manufacturing facilities, significantly reducing capital investment and operational costs while still producing acceptable silicon-carbon composites.
Solution Approach 2:
The patent extracts the essential function of CVD (creating silicon-carbon composite) and achieves it through simpler processes. By taking out the complex CVD equipment requirement and replacing it with basic mixing and drying operations, the patent maintains composite quality while dramatically reducing manufacturing complexity and cost.
4Manufacturing precision
If CVD method is used to manufacture silicon-carbon composite, then composite quality is improved, but device complexity increases
Solution Approach 1:
The patent eliminates the need for sophisticated CVD equipment by using simple, readily available manufacturing equipment such as mixers, spray dryers, or freeze dryers. These devices are standard in most production facilities and do not require specialized infrastructure, thereby reducing device complexity while maintaining manufacturing capability.
Solution Approach 2:
The patent extracts the core functionality of CVD (producing silicon-carbon composite material) and achieves it through much simpler processes using basic equipment. This extraction of the essential function from the complex CVD system reduces device complexity while preserving the ability to manufacture quality composites.
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 composite anode achieves high energy density and cycling performance with reduced volume expansion, providing a practical and eco-friendly manufacturing process for lithium-ion batteries, suitable for various applications including electronic devices and automobiles.
Implementation Method 1
An electrophoretic deposition method is provided for making the composite anode of this invention
Data Source
AI summary
The present invention provides a composite anode for a battery comprising a copper current collector working electrode, at least one anode material comprising at least one of a carbon, a silicon, a conductive agent, and combinations thereof, wherein at least one anode material is deposited on a surface of the copper current collector working electrode to form the composite anode for a battery. An electrophoretic method for making this anode is provided. A lithium-ion battery having the composite anode is disclosed.