Portable Charger Device for Electric Grass Mowers

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Solution Overview

Problem

Existing portable charger devices for electric vehicles do not efficiently charge both the auxiliary battery and the vehicle-side battery, and their layout in electric grass mowers is hindered by limited space and weight considerations, leading to inefficiencies in charging and vehicle stability.

Innovation Solution

A portable charger device with a wheeled frame, comprising a charger device side battery for non-quick charging and a second charging control section for quick charging of the vehicle-side battery, along with a solar cell unit for energy harvesting, and a contactless charger system with a primary coil unit on the ground and a secondary coil at a lower portion of the vehicle body, optimized for efficient charging and reduced weight and space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a large battery is mounted to enable extended driving period, then driving duration is improved, but vehicle weight and occupying space increase

Engineering Contradiction:

Improvedriving durationVSAvoidvehicle weight

Core Design Contradiction:

Duration of action of moving objectVSWeight of moving object

Solution Approach 1:

The battery system is segmented into two parts: a main vehicle-side battery for primary power supply and a smaller auxiliary charger device battery for extended range. This segmentation allows the vehicle to achieve extended driving duration without mounting a single large battery that would increase weight and space requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary charger device acts as an intermediary between external power sources and the vehicle-side battery. It includes a battery that can be charged externally and then used to charge the vehicle-side battery, enabling extended range without requiring the vehicle to carry a large battery.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If a large battery is mounted to enable extended driving period, then driving duration is improved, but vehicle occupying space increases

Engineering Contradiction:

Improvedriving durationVSAvoidvehicle occupying space

Core Design Contradiction:

Duration of action of moving objectVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If the auxiliary battery is charged from the vehicle-side battery, then charging capability is improved, but driving time is reduced

Engineering Contradiction:

Improvecharging capabilityVSAvoiddriving time

Core Design Contradiction:

Ease of manufactureVSDuration of action of moving object

Solution Approach 1:

The auxiliary charger device battery is charged in advance from external power sources (AC outlets, DC cigarette lighters, or solar panels) before the vehicle needs extended range. This preliminary charging action ensures that when the vehicle-side battery needs replenishment, the auxiliary battery is already charged and ready to transfer power, avoiding the need to deplete the vehicle-side battery to charge the auxiliary battery.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If the secondary coil is disposed at a lower portion of the vehicle body, then contactless charging efficiency is improved, but vehicle stability is worsened

Engineering Contradiction:

Improvecharging efficiencyVSAvoidvehicle stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The secondary coil is disposed at a lower portion of the vehicle body in the vertical dimension, close to the ground where the primary coil is located. This vertical positioning improves electromagnetic coupling and charging efficiency without significantly affecting the horizontal weight distribution that determines vehicle stability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

The solution enables balanced emergency and non-emergency charging, reduces the load on the electric vehicle, and improves vehicle stability by optimizing battery placement and charging efficiency, while utilizing solar energy to lower operational costs.

Implementation Method 1

a solar cell unit; and a third charging control section for charging the charger device side battery by power supply from the solar cell unit

Methodology Applied

Scientific EffectSolar energy conversion: Photovoltaic Effect

Implementation Method 2

a secondary side contactless power transfer pad (a secondary coil) configured to receive electric power via electromagnetic coupling with a primary side contactless power transfer pad (a primary coil)

Methodology Applied

Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentUS10538166B2Portable charger device, contactless charger system for electric work vehicle and electric grass mower machine

Publication Date: 2020.01.21 KUBOTA CORP

AI summary

A portable charger device 200 includes a charger device side battery 3, a first charging control section 31 for non-quick charging of the charger device side battery 3 by power supply from an external power source 8, and a second charging control section 32 for quick charging of a vehicle side battery 4 mounted on an electric vehicle 100 by power supply from the charger device side battery 3.