Inductive Charging Coil Air Gap Minimization via Ferrofluid
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Solution Overview
Problem
Existing inductive charging arrangements for vehicles require displacement of the primary or secondary coil to minimize the air gap for efficient energy transfer, which is inefficient and costly, especially when aligning the coils precisely.
Innovation Solution
Incorporating a reversibly deformable container filled with a liquid of high magnetic conductivity, such as ferrofluid, that deforms to minimize the air gap between the primary and secondary coils without moving the coils themselves, allowing for efficient magnetic flux and power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the primary coil arrangement or secondary coil arrangement is displaced to minimize the air gap, then the inductive coupling efficiency is improved, but the device complexity and alignment precision requirements increase
Solution Approach 1:
The patent changes the magnetic properties of the medium in the air gap by introducing a liquid of high magnetic conductivity (ferrofluid). This parameter change transforms the air gap from a high-reluctance region to a low-reluctance magnetic path, achieving efficient inductive coupling without mechanical displacement of the coils.
Solution Approach 2:
The liquid of high magnetic conductivity acts as an intermediary substance between the primary and secondary coil arrangements. It mediates the magnetic flux transmission by providing a continuous magnetic path that bridges the air gap, eliminating the need for direct coil-to-coil contact or complex displacement mechanisms.
2Power
If the air gap between primary coil arrangement and secondary coil arrangement is minimized, then the power transmission is improved, but the manufacturing precision and alignment requirements increase
Solution Approach 1:
The patent modifies the magnetic conductivity parameter of the medium between the coils by using a liquid with high magnetic conductivity properties. This allows the system to achieve high power transmission with larger tolerances in coil alignment, as the liquid adapts to fill irregularities and maintain a continuous magnetic path.
Solution Approach 2:
The liquid of high magnetic conductivity provides a dynamic solution to the alignment problem. It can flow and redistribute itself to maintain optimal magnetic coupling even when coil positions vary within certain tolerances, making the system less sensitive to manufacturing precision requirements.
3Loss of energy
If a mechanically lifting mechanism is used to raise the primary coil, then the air gap is reduced, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical lifting mechanism with a magnetic field-based solution. Instead of using motors, actuators, or bellows to physically move the coils closer, the system uses a magnetically conductive liquid that passively fills the gap and establishes efficient magnetic coupling, eliminating complex mechanical subsystems.
Solution Approach 2:
The liquid of high magnetic conductivity serves as a simple, low-cost intermediary that achieves the same functional result as expensive mechanical lifting mechanisms. It provides a continuous magnetic path without requiring precision mechanical components, reducing manufacturing complexity and cost.
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 solution reduces the magnetic resistance and enables high electrical power transmission without the need to displace the coils, offering cost advantages and improved alignment flexibility, while minimizing heat development by using pulsed direct current.
Implementation Method 1
a liquid of high magnetic conductivity, such as ferrofluid
Implementation Method 2
electric energy can be transmitted from the primary coil to the secondary coil
Data Source
AI summary
An inductive charging arrangement for a vehicle battery having a counter coil arrangement which comprises at least one primary coil arrangement located outside the vehicle and at least one secondary coil arrangement located inside the vehicle, wherein primary coil arrangement and secondary coil arrangement each comprise a coil and a magnetic core and, with appropriate positioning of the vehicle and energizing of the primary coil arrangement, electric energy is transmitted by inductive coupling from the primary coil arrangement to the secondary coil arrangement wherein the air gap is part of the transmission region and means are provided to minimize the air gap between the primary coil arrangement and the secondary coil arrangement.