Battery Remaining Amount Detection Using Voltage Change Calculation

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Solution Overview

Problem

Existing methods for accurately tracking the remaining amount of batteries in electric vehicles and power supply units are complex and prone to errors, particularly when using current integration or open-circuit voltage estimation methods.

Innovation Solution

A battery remaining amount detection unit that measures voltage, calculates an estimated open-circuit voltage by determining voltage change amounts between no-load and closed-circuit conditions, and uses this to detect the remaining battery amount without requiring current measurement units, thereby simplifying the process and reducing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a method of calculating remaining amount from open-circuit voltage is used, then measurement precision is improved, but device complexity increases due to requiring current measurement units and complex estimation processes

Engineering Contradiction:

Improveremaining amount detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the current measurement unit from the detection system. Instead of measuring current and integrating it to determine remaining amount, the system only measures voltage and uses a simplified calculation process that directly computes remaining amount from voltage readings through basic arithmetic operations, thereby reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the complex electrochemical measurement system (current integration) with a simplified mathematical calculation system. By substituting the physical current measurement and integration process with voltage-based arithmetic calculations, the system achieves the same measurement precision with significantly reduced device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If current integration method is used to track remaining amount, then reliability is improved, but device complexity increases due to requiring current measurement units and integration processes

Engineering Contradiction:

Improveremaining amount tracking accuracyVSAvoiddetection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the current measurement unit and integration process from the system. The remaining amount is calculated directly from voltage measurements using a simplified formula that incorporates voltage change amounts, eliminating the need for complex current integration while maintaining reliable tracking accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the current integration method with a voltage-based calculation method. By replacing the physical measurement and integration of current with mathematical operations on voltage readings, the system achieves equivalent reliability with reduced device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If open-circuit voltage estimation with change amount reflection is used, then measurement precision is improved, but ease of operation worsens due to complicated estimation processes

Engineering Contradiction:

Improveopen-circuit voltage estimation accuracyVSAvoidestimation process simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the complex iterative estimation process with straightforward arithmetic calculations. The open-circuit voltage is computed by adding a calculated voltage change amount to the measured voltage, where the voltage change amount is derived from basic voltage differences, making the process easy to operate while maintaining high estimation precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9506989B2Battery remaining amount detection unit, electric vehicle, and electric power supply unit

Publication Date: 2016.11.29 MURATA MFG CO LTD

AI summary

A battery remaining amount detection unit includes: a voltage measurement section configured to measure a voltage of a battery; an open-circuit voltage calculation section configured to calculate an estimated open-circuit voltage; and a remaining amount detection section configured to detect a remaining amount of the battery from the estimated open-circuit voltage, in which the open-circuit voltage calculation section is configured to calculate a first voltage change amount as a voltage change amount from a no-load voltage when no load is applied to the battery and a closed-circuit voltage when a load is applied to the battery, and the open-circuit calculation section is configured to calculate the estimated open-circuit voltage based on the closed-circuit voltage of the battery and the first voltage change amount.