Switchable Battery Pack Control for Voltage Balance and Contact Failure

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Solution Overview

Problem

Existing battery packs face issues with voltage imbalance and contact failures between cell units, requiring multiple packs for different voltage needs and lacking convenient voltage switching capabilities.

Innovation Solution

A battery pack with a microcomputer and protection circuit that monitors cell unit voltages and temperatures, detects contact failures, and adjusts voltage balance by switching connection states, including series and parallel configurations, with a control unit to manage power supply and notify abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a plurality of battery units are provided inside a battery pack to support different voltages, then adaptability to different electrical apparatuses is improved, but voltage imbalance between cell units occurs due to power consumption differences and contact failures

Engineering Contradiction:
Improvevoltage compatibilityVSAvoidvoltage balance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a control unit that continuously monitors voltage levels of individual cell units and provides feedback to adjust connection states. The control unit detects voltage imbalances between series-connected battery units and automatically switches connection configurations (series/parallel) to maintain voltage balance, resolving the contradiction between adaptability and reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The battery pack employs dynamic switching between series and parallel connection states of battery units based on real-time voltage conditions. This dynamic reconfiguration allows the system to adapt to different voltage requirements while maintaining optimal voltage balance, preventing the reliability issues that would arise from static connections.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple battery packs are prepared for different voltage needs, then voltage balance is maintained, but device complexity and user convenience deteriorate

Engineering Contradiction:
Improvevoltage balanceVSAvoidbattery pack variety
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal battery pack design that can output multiple voltages (e.g., 18V, 36V, 54V) by dynamically reconfiguring the connection states of its internal battery units. This single multi-functional pack replaces the need for multiple specialized packs, reducing device complexity while maintaining reliable voltage balance through automated control.

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

3Adaptability or versatility

If connection terminals are provided for voltage switching, then adaptability is improved, but contact failure risk increases leading to voltage imbalance

Engineering Contradiction:
Improvevoltage switching capabilityVSAvoidcontact stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical switching mechanisms with electronic control for voltage selection. The control unit electronically switches between series and parallel connection states based on detected voltage requirements, eliminating mechanical contact components that are prone to failure and improving contact stability while maintaining adaptability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3660944B1Battery pack and electrical device using battery pack
Publication Date: 2025.10.15 KOKI HLDG CO LTD
  • EP3660944B1 patent drawingFigure 1
  • EP3660944B1 patent drawingFigure 2
  • EP3660944B1 patent drawingFigure 3

AI summary

A battery pack 100 which has cell units 146, 147 in which top-side and bottom-side battery cells are connected in series, and is capable of switching the connection state of the cell units 146, 147, wherein a control unit 350 monitors voltage imbalances between the plurality of cell units, and also monitors whether or not a cell unit contact failure has occurred. In order to stop a charging/discharging when a contact failure occurs, a signal (abnormality stoppage signal 341 or charging stoppage signal 441) for stopping discharge is produced and outputted to the electrical device body-side.