EV Wireless Charging Coil Spacing for Efficient Power Transfer
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Solution Overview
Problem
The performance of wireless charging devices in electric vehicles is affected by the distance and composition of components such as the coil and magnetic units, leading to variations in charging efficiency, assembly difficulty, and durability.
Innovation Solution
A wireless charging device with a coil unit, a magnetic unit, and a shield unit, where the distance between the coil and magnetic units is optimized within a specific range (0.5 mm to 7 mm) to satisfy the relationship (Q+Ls)/(D^2×Rs) ≥ 1 at 85 kHz, achieving a Q factor of 300 to 1000, inductance of 30 μH to 200 μH, and resistance of 40 mΩ to 200 mΩ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic body is spaced apart from the coil, then the assembly is easier and durability is enhanced, but the inductance decreases and charging efficiency reduces
Solution Approach 1:
The patent applies parameter changes by optimizing the distance parameter D between the coil and magnetic body within a specific range (0.5-7mm) and adjusting electrical parameters (inductance Ls, resistance Rs, Q factor) to satisfy the mathematical relationship (Q+Ls)/(D²×Rs)≥1. This resolves the contradiction by finding the optimal balance point where sufficient spacing for durability is maintained while charging efficiency is preserved through coordinated adjustment of multiple parameters.
2Productivity
If the magnetic body is placed close to the coil, then the inductance is increased and charging efficiency is improved, but assembly becomes difficult and the device is vulnerable to impact
Solution Approach 1:
The patent resolves assembly difficulty by changing the distance parameter D to a optimized range (0.5-7mm) that provides sufficient clearance for manufacturing and assembly operations, while compensating for the reduced inductance through coordinated adjustment of coil parameters (turns, wire diameter, winding density) to maintain the required (Q+Ls)/(D²×Rs)≥1 relationship.
3Reliability
If the distance between coil and magnetic body is increased, then durability is enhanced, but the Q factor decreases and heat generation increases
Solution Approach 1:
The patent addresses heat generation by optimizing the distance parameter D within 0.5-7mm to balance durability and thermal performance. The controlled distance prevents excessive heat while the adjusted coil parameters (inductance Ls, resistance Rs) and magnetic body configuration maintain the (Q+Ls)/(D²×Rs)≥1 relationship, ensuring efficient power transfer and reduced thermal losses.
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 configuration enhances charging efficiency, simplifies assembly, and improves durability, making it suitable for large-capacity power transmission in electric vehicles.
Implementation Method 1
The wireless power transmission refers to wirelessly transmitting power through space using inductive coupling, capacitive coupling, or an electromagnetic field resonance structure such as an antenna
Implementation Method 2
a magnetic unit disposed on the coil unit
Data Source
AI summary
The wireless charging device according to an embodiment allows adjustment of characteristics, including the distance between a coil and a magnetic material, to be within particular numerical ranges and thus has high charging efficiency, facilitates assembly, and can be improved in durability. Therefore, the wireless charging device is useful in a transportation means, such as an electric vehicle, requiring high-capacity power transmission between a transmitter and a receiver.