Voltage Measuring Circuit for Battery Noise Reduction

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Solution Overview

Problem

Existing voltage measuring circuits for secondary batteries face challenges in accurately measuring inter-terminal voltage due to noise interference from drive or stationary apparatuses, which can lead to measurement inaccuracies and processor malfunctions.

Innovation Solution

A voltage measuring circuit that employs a detection resistor connected in parallel to the battery terminals, measures current flow, integrates and averages the current values over time, and uses insulated communication to separate ground potentials, allowing for accurate voltage calculation while reducing noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the inter-terminal voltage is measured using a voltage-dividing circuit with fixed resistors and an operational amplifier, then the voltage measurement can be obtained, but noise from drive apparatus or stationary apparatus superimposes on the voltage signal, degrading measurement accuracy

Engineering Contradiction:
Improveinter-terminal voltage measurement accuracyVSAvoidnoise interference from drive apparatus or stationary apparatus
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the voltage measurement function into multiple measurement cycles, measuring the voltage at different time points and calculating the average value. This temporal segmentation allows the circuit to capture multiple samples and filter out noise through averaging, improving measurement accuracy without requiring additional hardware shielding or filtering components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic voltage measurement by repeatedly measuring the inter-terminal voltage at different time points within a measurement period. The control unit performs multiple measurements in succession and calculates the average, utilizing periodic sampling to reduce the impact of transient noise and achieve more stable and accurate voltage readings.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the voltage is measured continuously to ensure accurate monitoring for over-charge and over-discharge protection, then safety is improved, but power consumption increases

Engineering Contradiction:
Improveover-charge and over-discharge protectionVSAvoidpower consumption of voltage measuring circuit
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic measurement instead of continuous measurement, where the voltage is sampled at specific time intervals determined by a measurement period. The control unit performs multiple measurements within each period and calculates the average, enabling reliable voltage monitoring while significantly reducing power consumption compared to continuous measurement operations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts the measurement strategy by varying the number of measurement cycles and the measurement period based on battery state and operational conditions. This dynamic approach allows the system to maintain reliable protection functionality while optimizing power consumption by reducing measurement frequency when full monitoring is not critical.

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 enables precise voltage measurement across battery terminals by averaging current values and separating ground potentials, thereby reducing noise emission and stabilizing voltage measurement, preventing processor malfunctions and minimizing power consumption.

Implementation Method 1

a detection resistor 14 that is connected in parallel to the two terminals; current detection means that measures the current value that flows in the detection resistor

Methodology Applied
Scientific EffectOhm's law: Ohm's Law

Implementation Method 2

integration means that subjects the current value that was measured by the current detection means to time quadrature

Methodology Applied
Scientific EffectTime quadrature (integration):

Data Source

PatentEP2592427B1Voltage measuring circuit and method
Publication Date: 2021.11.10 ENVISION AESC JAPAN LTD
  • EP2592427B1 patent drawingFigure 1~2

AI summary

An average current value that is the average value of current values is found by connecting a detection resistor in parallel to two terminals that are the object of measurement, measuring the current value that flows in the detection resistor, and subjecting the current value to time-quadrature, and further, dividing the current value that follows integration by the integration time. The average current value is converted to a digital signal and sent to an arithmetic means (processor). The arithmetic means calculates the voltage value across the two terminals from the average current value and the resistance value of the detection resistor.