Thermochromic Foreign Object Detection for Wireless Power Transfer

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Solution Overview

Problem

Existing power transmission devices require both an infrared sensor and a thermographic camera to detect foreign objects, resulting in a complex configuration.

Innovation Solution

A foreign object detection device with a temperature-sensitive body that changes color with temperature, coupled with a detection unit to identify foreign objects by detecting color changes, allowing for simpler configuration and detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If both an infrared sensor and a thermographic camera are installed to detect foreign objects, then detection reliability is improved, but device complexity increases

Engineering Contradiction:

Improveforeign object detection reliabilityVSAvoiddetection device configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies thermochromic material that changes color in response to temperature changes caused by foreign object heating. This color change is detected by a simple camera, replacing the need for complex infrared sensors and thermographic cameras while maintaining detection reliability

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent substitutes complex optical detection systems (infrared sensors and thermographic cameras) with a simpler visual detection system using color-changing material and a standard camera, reducing device complexity while achieving the same detection function

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 the detection of foreign objects on the power transmission unit with a reduced and simpler setup, preventing erroneous detection and unnecessary power transmission interruptions.

Implementation Method 1

a temperature sensitive body disposed at the power transmission unit and changing a color with temperature

Methodology Applied

Scientific EffectThermochromism: Thermochromism

Data Source

PatentUS11731521B2Foreign matter detection device and power transmission device

Publication Date: 2023.08.22 IHI CORP

AI summary

A foreign object detection device detects, during wireless power transfer from a power transmission unit of a power transmission device to a power reception unit of a power reception device, a foreign object on the power transmission unit, and comprises: a temperature sensitive body that is disposed at the power transmission unit and changes a color with temperature; and a detection unit that detects the foreign object by detecting a change in the color.