Copper-Graphene Current Collector Joining for Skin Effect Loss
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Solution Overview
Problem
Existing conductors in electric and hybrid electric vehicles face challenges due to the skin effect, which increases resistance as frequency increases, necessitating the development of new conductors and methods for joining them effectively.
Innovation Solution
The use of a copper-graphene multilayer composite in conductors, combined with a fusion zone formed during joining, enhances electrical conductivity and resistance to the skin effect. This composite structure includes alternating layers of graphene and copper, graphene particles in a copper matrix, or graphene layers on a copper foil, which are joined using methods like laser welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional conductors are used in AC power distribution, then the structure is simple and easy to manufacture, but the skin effect increases resistance as frequency increases
Solution Approach 1:
The patent applies composite materials by coating conventional copper conductors with graphene layers to form a copper-graphene composite conductor. The graphene coating has superior electrical conductivity and addresses the skin effect by providing a low-resistance surface path for high-frequency currents, thereby reducing resistance loss while maintaining the underlying copper conductor's structural simplicity
Solution Approach 2:
The patent changes the surface electrical conductivity parameter of the conductor by applying graphene coating. This parameter change allows the conductor to maintain low resistance at high frequencies by utilizing graphene's exceptional electrical conductivity at the surface, effectively counteracting the skin effect without fundamentally altering the conductor's core structure
2Reliability
If copper-graphene multilayer composite is used to reduce skin effect, then electrical conductivity improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the copper conductor with graphene layers before the conductor is installed or assembled into the final product. This allows the complex composite structure to be manufactured separately and then integrated, simplifying the overall manufacturing process while maintaining the electrical conductivity benefits
Solution Approach 2:
The patent uses the copper conductor as an intermediary substrate that carries the graphene coating. The copper provides mechanical strength and structural stability, while the graphene layer provides the enhanced electrical conductivity, allowing each material to fulfill its optimal function without requiring complete replacement of the conventional conductor
3Loss of energy
If graphene coating is applied to conductor surface, then skin effect resistance decreases, but joining difficulty increases
Solution Approach 1:
The patent applies taking out by selectively removing or exposing the copper substrate at the joining areas where connections are made. This allows conventional joining methods to be used on the copper surface while the graphene coating remains intact on the non-joining portions, thereby maintaining the skin effect resistance benefits without compromising the joining process
Solution Approach 2:
The patent applies local quality by having different surface properties at different locations on the conductor: the graphene coating is present on the current-carrying surfaces to reduce skin effect resistance, while the joining areas have exposed copper or modified surface properties to facilitate conventional joining processes
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 copper-graphene multilayer composite significantly improves the conductivity of electrical connections, reducing the impact of the skin effect and enhancing the overall efficiency of energy transfer in vehicle propulsion systems.
Implementation Method 1
current density tends to be larger near the surface of conductors, such as the windings and busbars of the stator, and decreases approaching the core of the conductors. This effectively decreases the cross-section of the larger conductors and increases effective resistance. This effect, known as the skin effect, increases as the frequency of the alternating current increases.
Implementation Method 2
The conductor is joined at the second joining area to the first joining area of the first electrical component. In addition, the electrical connection includes a fusion zone formed in the first electrical component in the first joining area.
Data Source
AI summary
An electrical connection for a vehicle and methods of forming an electrical connection for a vehicle. The electrical connection includes a first electrical component including a first joining area. The electrical connection also includes a conductor including a second joining area. The conductor is joined at the second joining area to the first joining area of the first electrical component. In addition, the electrical connection includes a fusion zone formed in the first electrical component in the first joining area. The conductor includes a copper-graphene multilayer composite formed on the surface of the conductor, the composite including at least one of the following composite structures: a) alternating layers of graphene and copper deposited on the substrate, b) graphene particles dispersed in a copper matrix, and c) alternating layers of graphene and copper deposited on a copper foil, wherein the copper foil is wrapped around the substrate.