On-Battery RC Circuit for Non-Contact Capacity Sensing

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Solution Overview

Problem

Existing battery testers require manual handling or physical connection for capacity assessment, and existing remote sensing methods are complex or limited in functionality.

Innovation Solution

A remote charge indicator system using on-battery circuitry with an RC circuit and a handheld computing device to determine battery capacity through time-based voltage measurements, providing a signal to a display for capacity indication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual battery testing using thermochromic testers is used, then battery capacity can be tested, but manual handling and physical connection are required

Engineering Contradiction:
Improvemanual handling requirementVSAvoidautomatic testing capability
Core Design Contradiction:
Ease of operationVSExtent of automation

Solution Approach 1:

The patent replaces manual mechanical connection and thermochromic visual indication with an automated electronic system using NFC/RFID communication and electronic display to show battery capacity, eliminating the need for manual handling and physical button pressing

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

Solution Approach 2:

The battery pack includes integrated circuitry that automatically measures its own state of charge and communicates this information wirelessly to the portable device, enabling the battery to self-test and self-report capacity without external manual intervention

Inventive Principle:
Principle #25Self-service

2Ease of operation

If remote sensing methods are implemented, then non-contact battery capacity determination is achieved, but system complexity increases

Engineering Contradiction:
Improvenon-contact testing capabilityVSAvoidcircuitry and communication system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The portable device combines multiple functions into a single device: it serves as both a communication device (NFC/RFID reader) and a battery testing device, using the same processor and display hardware for both general operation and battery capacity display, thereby reducing overall system complexity

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

Solution Approach 2:

The battery capacity measurement circuitry is integrated within the battery pack housing, with the NFC/RFID tag embedded in the battery pack, creating a nested structure where the communication and measurement systems are contained within the existing battery form factor, minimizing additional complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

3Illumination intensity

If thermochromic ink display is used, then visual capacity indication is provided, but manual connection and physical handling are required

Engineering Contradiction:
Improvevisual indication capabilityVSAvoidmanual connection requirement
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The patent replaces the thermochromic ink physical display with an electronic display on a portable computing device that shows battery capacity information digitally, eliminating the need for physical thermochromic materials and manual connection to activate the display

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

Solution Approach 2:

The patent introduces wireless communication (NFC/RFID) as an intermediary between the battery pack and the display system, allowing capacity information to be transmitted electronically without requiring physical connection between the battery and the display device

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables non-contact, efficient determination of battery capacity using a handheld device, reducing manual intervention and complexity, and supporting various battery types and sizes.

Implementation Method 1

charging or discharging a capacitor of an RC circuit to a predetermined threshold voltage using a power source. A response signal is provided from a communications module to a handheld computing device comprising a reader system once the capacitor reaches the predetermined threshold voltage

Methodology Applied
Scientific EffectRC circuit charging/discharging: Capacitance

Implementation Method 2

As current travels through the silver resistor, the dissipated power generates heat that changes the color of a thermochromic ink display that is over the silver resistor

Methodology Applied
Scientific EffectThermochromism: Thermochromism

Implementation Method 3

a first NFC circuit carried by the battery casing and a second NFC circuit carried by the portable housing, wherein the second NFC circuit receives the power level measurement from the first NFC circuit based upon proximity therewith

Methodology Applied
Scientific EffectNear Field Communication: Electromagnetic Induction

Data Source

PatentEP4270028B1Remote sensing of remaining battery capacity using on-battery circuitry
Publication Date: 2026.04.15 DURACELL US OPERATIONS INC
  • EP4270028B1 patent drawingFigure 1
  • EP4270028B1 patent drawingFigure 2
  • EP4270028B1 patent drawingFigure 3~4

AI summary

A method of remote sensing a remaining battery capacity includes receiving an interrogation signal (17) from a reader system (15) of a handheld computing device (12) at a communications module (30) of a remote charge indicator system (14) operatively connected to a battery; upon said interrogation, charging or discharging a capacitor of an RC circuit (40) to a predetermined threshold voltage using a power source, wherein the power source is the battery; providing a response signal from said communications module (24) to the handheld computing device (12) comprising the reader system once the capacitor reaches the predetermined threshold voltage. The response signal is used to determine remaining battery capacity information using an amount of time taken for the capacitor to charge or discharge to the predetermined threshold voltage using a processor (20).