Battery Meter Timing for Accurate Remaining Capacity Under Load

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Solution Overview

Problem

Existing battery meter technologies inaccurately estimate the remaining capacity of rechargeable batteries, leading to incorrect announcements that can result in premature battery replacement or over-discharging, due to large current consumption affecting voltage measurements.

Innovation Solution

A battery meter with a voltage measurement unit, announcement unit, and recovery prediction function that announces remaining capacity information only when the electrical load is not supplied with power, and predicts recovered voltage to generate accurate capacity information, using visual indicators or voice generators for user feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the battery meter measures inter-terminal voltage during power supply to announce remaining capacity, then the announcement function is available during operation, but the measurement precision deteriorates due to large current affecting voltage readings

Engineering Contradiction:
Improveannouncement availabilityVSAvoidvoltage measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The battery meter performs remaining capacity announcement during periods when the electrical load is not supplied with power, before the next power supply cycle begins. This preliminary timing ensures voltage measurement accuracy is not compromised by current draw, while still providing timely information to the user before operation resumes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit acts as an intermediary that manages the timing between power supply cycles and announcement operations. It detects the power supply state and strategically schedules voltage measurements and remaining capacity announcements during idle periods, mediating between the need for accurate measurement and the need for timely information delivery.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If the battery meter continuously announces remaining capacity during all operations, then the user always has information, but incorrect estimates occur due to voltage fluctuations under load

Engineering Contradiction:
Improveinformation availabilityVSAvoidannouncement accuracy
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The battery meter performs remaining capacity announcements periodically during idle periods between power supply cycles, rather than continuously during operation. This periodic approach ensures that each announcement is based on accurate voltage measurements taken when no current is being drawn, eliminating the trade-off between information availability and accuracy.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If the battery meter uses voltage measurement for remaining capacity estimation, then the device complexity is low, but the measurement precision deteriorates when large current is consumed

Engineering Contradiction:
Improvemeasurement system simplicityVSAvoidremaining capacity estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The battery meter dynamically adjusts its measurement timing based on the power supply state. It detects when the electrical load is not supplied with power and schedules voltage measurements during these dynamic idle periods. This dynamic timing strategy maintains the simplicity of voltage-based measurement while ensuring measurements are always taken under optimal conditions for accuracy.

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

This solution stabilizes the announcement of remaining capacity information, reducing incorrect estimates and preventing over-discharging by accurately assessing battery state even during high current usage, thus extending battery life and user convenience.

Implementation Method 1

a voltage measurement unit for measuring an inter-terminal voltage of the rechargeable battery

Methodology Applied
Scientific EffectElectrical voltage measurement: Ohm's Law

Data Source

PatentEP2778702B1Battery meter and power tool including battery meter
Publication Date: 2024.09.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2778702B1 patent drawingFigure 1~2
  • EP2778702B1 patent drawingFigure 3~4
  • EP2778702B1 patent drawingFigure 5~6

AI summary

A battery meter (25) for use with a rechargeable battery (30) that supplies power to an electrical load. A voltage measurement unit (26) measures an inter-terminal voltage (Vt) of the rechargeable battery (30). An announcement unit (27) announces rechargeable battery remaining capacity information based on the measurement of the inter-terminal voltage. An announcement request switch (28) outputs an announcement request (SC) for requesting announcement of the remaining capacity information. The announcement unit announces the remaining capacity information when the announcement request is received during a period in which the electrical load is not supplied with power, and does not announce the remaining capacity information regardless of whether or not the announcement request is received during a period in which the electrical load is supplied with power.