Parallel Battery Power Management for Hand-Held Tools

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Solution Overview

Problem

Existing methods for powering electric hand-held power tools using a single battery result in excessive user weight, limited power availability, and integrated electronic drivers that cannot be separated from the battery, while connecting multiple batteries in parallel requires complex circuitries and generates losses.

Innovation Solution

An apparatus with connectors and switches allows for the connection of multiple batteries in parallel, using 'diode equivalent logic' managed by a DSP to balance power distribution without DC/DC converters or memory elements, enabling modular and efficient power management based on user needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If only one battery is used to power the electric hand-held power tool device, then the battery weight worn by the user is reduced to a manageable level (few kilos), but the power availability is limited and cannot be raised above the maximum available power

Engineering Contradiction:
Improvebattery weightVSAvoidpower availability
Core Design Contradiction:
Weight of moving objectVSPower

Solution Approach 1:

The power system is segmented into multiple independent battery packs (at least two) that can be connected in parallel to the electronic driver. Each battery pack operates independently with its own protection circuitry, allowing the system to distribute the total power requirement across multiple lighter units rather than relying on a single heavy battery.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple battery packs are merged in parallel connection to the electronic driver, combining their individual power outputs to achieve higher total power availability. The parallel connection architecture allows the batteries to work together as a unified power source while maintaining individual independence through separate connectors and protection circuits.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If at least two batteries or battery packs are connected in parallel using conventional DC/DC converters, then power availability is increased, but complex electronic circuitries are required and energy losses occur

Engineering Contradiction:
Improvepower availabilityVSAvoidelectronic circuitry complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The complex DC/DC converter circuitry is extracted and removed from the system. Instead of using conventional voltage conversion methods, the patent directly connects multiple battery packs in parallel to the electronic driver through simple switches and protection circuitry, eliminating the need for complex conversion electronics while maintaining power availability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Each battery pack is equipped with its own protection circuitry and intelligence that autonomously manages its own operation, voltage regulation, and safety parameters. This self-service capability eliminates the need for complex centralised control circuitry to manage voltage matching and power distribution across multiple batteries.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the electronic driver is integrated with the battery in the same housing, then the device structure is simplified, but it becomes impossible to change a battery without changing the electronic driver and to separate the battery intelligence from the electronic driver

Engineering Contradiction:
Improvedevice structureVSAvoidbattery interchangeability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system is segmented into separate functional modules: the electronic driver housing containing the control electronics and at least two battery packs with independent connectors. This modular architecture allows the battery packs to be independently removed, replaced, or upgraded without affecting the electronic driver, enhancing adaptability and interchangeability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electronic driver is designed with universal parallel connection capability that can accommodate at least two different battery packs through separate connectors. This multi-functional design allows the same electronic driver to work with various battery configurations and types, providing versatility and future-proofing the system against technological changes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2451044B1Method and apparatus for powering an electric hand-held power tool device
Publication Date: 2014.04.30 FELCO SA
  • EP2451044B1 patent drawingFigure 1A~1B
  • EP2451044B1 patent drawingFigure 2
  • EP2451044B1 patent drawingFigure 3

AI summary

An apparatus for powering an electric hand-held power tool device (20) by an output voltage (U) comprising at least two connectors (J11, J21) for connecting said apparatus to at least two batteries (B1, B2) at least two switches (10, 14) a command circuit of said switches (10, 14), said command circuit being arranged for commanding the powering of said electric hand-held power tool device by using - the battery (B1) which presents the highest open circuit voltage (OCV1) if said output voltage (U) is higher than the open circuit voltage (OCV2) of each of the other batteries - the battery (B1) which presents the highest open circuit voltage (OCV1) and at least one other battery (B2) if the said output voltage (U) is lower than the open circuit voltage (OCV2) of said other battery (B2), said battery (B1) which presents the highest open circuit voltage (OCV1) and said at least one other battery (B2) being connected in parallel.