Contactless Power Supply Foreign Object Detection via Dissolving Wire
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Solution Overview
Problem
Existing contactless power supply devices struggle to accurately detect foreign objects, such as metal, without erroneously identifying dirt, mud, or water as a foreign object, which can lead to incorrect detection and potential fires.
Innovation Solution
A contactless power supply device and receiving device configuration that includes a power supply coil, a case, a wire that dissolves at a temperature below the case's heat-resistant temperature, and a dissolution detection unit, allowing for accurate detection of foreign objects by monitoring the dissolution of the wire, which is arranged in a spiral shape to cover the power supply coil and is designed to dissolve before the case, ensuring reliable detection regardless of dirt adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light emitting member and light receiving member are used to detect foreign objects, then foreign object detection is enabled, but dirt, mud, or water droplets are erroneously detected as foreign objects
Solution Approach 1:
A wire is introduced as an intermediary element between the power supply coil and the foreign object detection system. The wire serves as a mediator that dissolves at a specific temperature threshold, providing a clear distinction between actual foreign objects (metal) and environmental contaminants (dirt, water, mud). This intermediary mechanism enables reliable detection by translating thermal effects into a detectable dissolution event.
Solution Approach 2:
The detection method changes from direct optical detection to thermal parameter-based detection. By monitoring temperature changes and the dissolution point of the wire, the system distinguishes between foreign objects that generate heat through electromagnetic induction and environmental contaminants that do not. This parameter change from optical to thermal detection resolves the false positive issue.
2Measurement precision
If the wire dissolves at a temperature below the case's heat-resistant temperature, then accurate foreign object detection is achieved, but the wire must be precisely positioned and controlled
Solution Approach 1:
The wire performs multiple functions automatically: it serves as both a thermal conductor to transfer heat from foreign objects and a detection element that dissolves at a specific temperature. The system self-regulates by using the wire's dissolution as the detection signal, eliminating the need for complex external sensing mechanisms and reducing overall device complexity.
Solution Approach 2:
The wire is designed to perform multiple functions simultaneously: it acts as a thermal pathway, a temperature sensor, and a detection trigger. This multi-functionality reduces the number of separate components needed, simplifying the device structure while maintaining high detection precision through the wire's controlled dissolution at a specific temperature threshold.
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
Enables accurate detection of heat-generating foreign objects while preventing non-magnetic materials and small objects from being incorrectly identified, ensuring safe operation and reducing costs through the use of an inexpensive detection system.
Implementation Method 1
a wire that dissolves at a temperature below a heat-resistant temperature of the case
Implementation Method 2
a power supply coil that generates an electromagnetic field and supplies power
Data Source
AI summary
Disclosed is a contactless power supply device which supplies power in a contactless manner, and adopts a configuration including a power supply coil that generates an electromagnetic field and supplies power, a case that houses the power supply coil, a wire that dissolves at a temperature below a heat-resistant temperate of the case, a dissolution detection unit that detects dissolution of the wire, and a controller that performs control based on a detection result of the dissolution detection unit.