Dual-Battery Power Tool Circuit for Communication Continuity

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Solution Overview

Problem

Existing electric power tools with a single battery face issues of insufficient working time due to power consumption by both the electric motor and communication device, and lose communication capability when the battery is removed.

Innovation Solution

The electric power tool is designed with a dual battery system, where a first battery powers the motor and controller, and a second battery powers the communication device, with a backflow suppression circuit to manage current flow between the batteries, ensuring efficient use and maintaining communication functionality even when the main battery is removed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single battery is used to power both the electric motor and communication device, then the device complexity is reduced, but the working time is insufficient due to power consumption by both components

Engineering Contradiction:
Improvebattery configurationVSAvoidworking time
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The power supply system is segmented into two independent batteries: a main battery for powering the electric motor and a sub battery for powering the communication device. This segmentation allows each battery to independently supply power to its designated component, thereby extending the overall working time of the tool without increasing the complexity of the power management system.

Inventive Principle:
Principle #1Segmentation

2Duration of action of moving object

If a built-in power supply is added to the electric power tool, then the working time is extended, but the built-in power supply cannot be effectively used due to current backflow when the main battery is driving the motor

Engineering Contradiction:
Improveworking timeVSAvoidenergy waste
Core Design Contradiction:
Duration of action of moving objectVSLoss of energy

Solution Approach 1:

A backflow suppression circuit is introduced as an intermediary component between the main battery and sub battery. This circuit acts as a mediator that prevents current from flowing backward from the main battery to the sub battery when the motor is operating, thereby eliminating energy waste and ensuring the sub battery remains effectively charged for communication device operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single battery is used, then the device structure is simplified, but communication cannot be performed when the battery is removed

Engineering Contradiction:
Improvepower supply structureVSAvoidcommunication functionality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The power supply structure is segmented such that the sub battery is electrically connected to the communication device through a backflow suppression circuit, creating an independent power path. This segmentation ensures that when the main battery is removed, the communication device can still draw power from the sub battery, maintaining communication functionality while keeping the overall structure relatively simple.

Inventive Principle:
Principle #1Segmentation

4Duration of action of moving object

If dual battery system is implemented without backflow suppression, then the working time is extended, but current backflow causes the sub battery to be discharged when main battery powers the motor

Engineering Contradiction:
Improveworking timeVSAvoidenergy efficiency
Core Design Contradiction:
Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The backflow suppression circuit serves as an intermediary that selectively controls current flow between the main battery and sub battery. It permits current flow from the sub battery to charge the main battery when needed, while blocking reverse current flow that would discharge the sub battery during motor operation, thereby optimizing energy efficiency in the dual battery system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4257296B1Electric power tool
Publication Date: 2025.11.05 MAX CO LTD
  • EP4257296B1 patent drawingFigure 1
  • EP4257296B1 patent drawingFigure 2
  • EP4257296B1 patent drawingFigure 3

AI summary

There is provided an electric power tool including: a second voltage supply portion configured to supply, based on a first power supply voltage supplied from a first battery, a second operating voltage for operating a second controller, and configured to supply, based on a second power supply voltage supplied from a second battery, the second operating voltage for operating the second controller; a first voltage line configured to connect a first voltage supply portion and the second voltage supply portion and configured to supply the first power supply voltage; and a backflow suppression circuit configured to permit a current to flow from the first voltage supply portion to the second voltage supply portion in the first voltage line and configured to suppress a current from flowing from the second voltage supply portion to the first voltage supply portion in the first voltage line.