Consumption Meter Battery Lifetime Estimation by Current Integration

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Solution Overview

Problem

Existing consumption meters using lithium thionyl chloride batteries face challenges in accurately estimating remaining battery lifetime due to the lack of correlation between voltage and capacity, necessitating a reliable method to determine battery replacement timing without significant battery consumption.

Innovation Solution

A consumption meter system comprising an accumulation module that calculates a first quantity based on current and time, and optionally temperature, to estimate remaining battery lifetime, transmitting these values to a battery lifetime estimation module for precise calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If voltage measurement is used to estimate battery capacity, then estimation simplicity is improved, but estimation accuracy deteriorates because lithium thionyl chloride battery voltage is not correlated with remaining capacity

Engineering Contradiction:
Improveestimation simplicityVSAvoidestimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from voltage to current integration (capacity). Instead of measuring voltage which does not correlate with remaining capacity in Li-SOCl2 batteries, the system integrates current over time to directly measure the capacity consumed, providing accurate estimation of remaining battery life.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If frequent current and time measurements are performed to accurately estimate battery lifetime, then estimation accuracy is improved, but battery consumption increases

Engineering Contradiction:
Improveestimation accuracyVSAvoidbattery consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary accumulation of current-time products during normal operation. The microcontroller continuously integrates current over time in the background without requiring additional measurement cycles, so that when lifetime estimation is needed, the value is already computed and ready, avoiding the energy cost of frequent measurements.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If battery capacity is monitored continuously to ensure timely replacement, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvebattery replacement timingVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the microcontroller perform the capacity monitoring as part of its normal operational tasks. The same processor that controls the meter also integrates current and calculates remaining lifetime, eliminating the need for dedicated monitoring hardware and reducing overall system complexity while maintaining reliable battery status tracking.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4386404B1Consumption meter and consumption meter system
Publication Date: 2026.05.06 KAMSTRUP
  • EP4386404B1 patent drawingFigure 1~2
  • EP4386404B1 patent drawingFigure 3~4
  • EP4386404B1 patent drawingFigure 5

AI summary

Described and claimed is a consumption meter comprising a battery for energy supply and an accumulation module. The accumulation module is configured for accumulating a first quantity over a time period to obtain a first accumulated quantity. The first quantity is based on a product of at least a current drawn from the battery and a duration over which the current was drawn from the battery. The accumulation module is further configured for transmitting the first accumulated quantity at regular or irregular intervals to a battery lifetime estimation module for calculating a remaining battery lifetime on basis of a nominal battery capacity, the received first accumulated quantity and an operating time of the battery. Further, α consumption meter system comprising a consumption meter and a battery lifetime estimation module are described and claimed.