Capacitor Placement for Wireless EV Power Transfer

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Solution Overview

Problem

The power receiving device in vehicles, when exposed to heat from exhaust pipes and catalysts, experiences resonance frequency fluctuations due to temperature variations, leading to reduced power transfer efficiency and potential damage during collisions.

Innovation Solution

The vehicle design positions the capacitor inside the vehicle body, away from heat sources, and strategically locates the electrical apparatus and insulation transformer to absorb impacts, ensuring the capacitor and electrical components are protected from thermal effects and collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the power receiving device is disposed on the bottom surface of the vehicle, then it can receive power from the ground-based transmission device, but it is susceptible to heat from exhaust pipes and catalysts which causes resonance frequency fluctuation and reduces power transfer efficiency

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidthermal effect from exhaust pipe and catalyst

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The capacitor is extracted from the power receiving device assembly and disposed separately in the vehicle body, away from the bottom surface. This separation removes the capacitor from the thermal environment of exhaust pipes and catalysts, preventing temperature-induced resonance frequency fluctuations while maintaining the power receiving device's ability to efficiently receive power on the bottom surface

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the capacitor is disposed inside the vehicle body away from heat sources, then thermal effects are suppressed, but the device complexity increases due to separate disposal of capacitor and power receiving coil

Engineering Contradiction:

Improvestability of capacitor against thermal effectVSAvoidspatial arrangement of electrical components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The capacitor and power receiving device are disposed in different spatial dimensions - the power receiving device remains on the bottom surface (horizontal plane) for efficient power reception, while the capacitor is disposed inside the vehicle body (vertical separation). This dimensional separation resolves the thermal protection requirement without significantly increasing overall device complexity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If the battery is located at the rear of the vehicle body, then it can be protected from front collisions, but the capacitor and electrical apparatus may be damaged in tail collisions

Engineering Contradiction:

Improveprotection of battery from collisionVSAvoidprotection of capacitor and electrical apparatus from tail collision

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The capacitor and electrical apparatus are disposed above the battery in the vertical direction, creating a layered protective arrangement. In the event of a tail collision, the battery's position below provides a protective barrier that absorbs impact forces before they reach the capacitor and electrical apparatus positioned above it

Inventive Principle:

Principle #10Preliminary action

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 effectively suppresses thermal effects on the capacitor, maintains power transfer efficiency, and protects the electrical components from damage during collisions by isolating them from heat sources and impact zones.

Implementation Method 1

a power receiving device configured to receive electrical power in a non-contact manner from a power transmission coil of a power transmission device disposed outside the vehicle body when facing the power transmission coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a capacitor disposed inside the vehicle body and electrically connected to the power receiving coil and the electrical apparatus

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9533592B2Vehicle

Publication Date: 2017.01.03 TOYOTA JIDOSHA KK

AI summary

An electrically powered vehicle is provided with a vehicle body having a bottom surface, a battery disposed inside the vehicle body, a power receiving device configured to receive electrical power in a non-contact manner from a power transmission coil of a power transmission device disposed outside the vehicle body when facing the power transmission coil, and an electrical apparatus electrically connected to the power receiving device and the battery for supplying power received from the power receiving device to the battery. The power receiving device includes a power receiving coil disposed on the bottom surface of the vehicle body, and a capacitor disposed inside the vehicle body and electrically connected to the power receiving coil and the electrical apparatus. Thereby, the impact of heat on the capacitor included in the power receiving device can be suppressed.