Power Adapter Dynamics for Electric Power Tool Battery Protection

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Solution Overview

Problem

Electric power tools with built-in converter circuits face issues with over-current and over-discharge when using battery packs with different rated voltages, leading to potential tool stoppage and reduced user workability.

Innovation Solution

An adapter with a converter unit, characteristic detection unit, and control unit that adjusts voltage and current output from the battery pack to prevent over-current and over-discharge by monitoring and controlling the power supply to maintain optimal operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the converter circuit performs step-up operation continuously to maintain rated voltage, then the voltage is improved, but over-current occurs and battery pack may be damaged

Engineering Contradiction:
Improvebattery pack temperatureVSAvoidbattery pack reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The converter circuit dynamically adjusts its operation mode between step-up and direct transmission based on real-time detection of battery pack voltage and tool body voltage requirements. When battery voltage is sufficient, the system switches to direct transmission mode, eliminating continuous step-up operation and preventing over-current conditions that would cause battery heating and damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the converter circuit by detecting battery pack voltage levels and adjusting whether to perform step-up conversion or direct transmission. This parameter change prevents the battery pack from operating in a state that would lead to over-current and thermal damage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the operation is stopped to prevent over-current or over-discharge, then the battery pack is protected, but user workability is worsened

Engineering Contradiction:
Improvebattery pack reliabilityVSAvoiduser workability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically switches between step-up mode and direct transmission mode based on battery pack voltage levels. When battery voltage is sufficient, direct transmission enables continuous tool operation without interruption. When voltage is insufficient, the system transitions to step-up mode temporarily, then returns to direct transmission, avoiding continuous operation in a harmful state while maintaining user workability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By implementing direct transmission mode when battery pack voltage is sufficient, the system ensures continuous operation of the tool without stoppage. The controller monitors voltage levels and maintains continuous useful action by switching to direct transmission, eliminating the need to stop operation for battery protection while still preventing over-current and over-discharge conditions.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If the converter circuit is provided in the tool body, then the adapter functionality is integrated, but the same over-current and over-discharge issues occur

Engineering Contradiction:
Improveadapter integrationVSAvoidbattery pack reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The controller continuously detects battery pack voltage and tool body voltage requirements, using this feedback to determine whether to operate in step-up mode or direct transmission mode. This feedback mechanism prevents continuous step-up operation that would cause over-current and battery damage, while still maintaining the integrated adapter functionality within the tool body.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The integrated converter circuit dynamically adjusts its operation based on real-time voltage detection. When battery pack voltage meets tool requirements, the system switches to direct transmission mode, eliminating the harmful continuous step-up operation. This dynamic adjustment protects the battery pack while maintaining the integrated design benefits.

Inventive Principle:
Principle #15Dynamics

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 adapter effectively suppresses over-current and over-discharge occurrences while ensuring continuous operation of the electric power tool, maintaining user workability and preventing battery pack damage.

Implementation Method 1

a converter unit configured to increase at least one of a voltage and a current outputted from a battery pack

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2696466B1Adapter and electric power tool
Publication Date: 2021.09.29 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2696466B1 patent drawingFigure 1
  • EP2696466B1 patent drawingFigure 2
  • EP2696466B1 patent drawingFigure 3

AI summary

An adapter includes a converter unit which increases at least one of voltage and current outputted from a battery pack and supply the increased the voltage and/or the current to a load, and a characteristic detection unit which detects at least one of the voltage outputted from the battery pack, the current outputted from the battery pack, a temperature of the battery pack, a voltage inputted to the load, a current inputted to the load and a temperature of the converter unit. The adapter further includes a control unit configured to control the converter unit to increase each of said at least one of the voltage and the current outputted from the battery pack to a corresponding reference value and perform a control operation of suppressing such increase to prevent an occurrence of over-current or over-discharge based on at least one detection result.