Button Cell Battery Safety Mechanism for Ingestion Short-Circuiting

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Solution Overview

Problem

Small button cell batteries, particularly those like CR2016 and CR2032 lithium cells, pose a risk of tissue damage and electrolysis when swallowed, as they can become lodged in the throat and cause electrolysis of body fluids or gastric distress due to their size and chemistry, which existing safety mechanisms fail to adequately address.

Innovation Solution

The battery design incorporates a housing with first and second poles and spacers made of electronically insulating materials that prevent electronic coupling under normal conditions but undergo a physical change in the presence of an aqueous solution, such as saliva or stomach fluids, to short-circuit the battery, reducing the cell voltage below harmful levels and preventing electrolysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If small button cell batteries are made compact for portability, then ease of operation and device miniaturization are improved, but the risk of tissue damage and electrolysis upon ingestion increases

Engineering Contradiction:
Improvebattery sizeVSAvoidtissue damage and electrolysis risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements a safety mechanism that proactively prevents harmful effects before they occur. A soluble spacer is positioned between the battery electrodes that dissolves upon contact with aqueous fluids (such as saliva or gastric juices), automatically triggering a short-circuit condition that reduces voltage to safe levels. This preliminary safety arrangement ensures that if the battery is ingested, the harmful electrical potential is eliminated before tissue damage or electrolysis can occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a soluble spacer as an intermediary element between the battery electrodes. This spacer acts as a temporary barrier that maintains electrical isolation during normal use but automatically removes itself (via dissolution in aqueous fluids) to enable safety short-circuiting. The intermediary spacer thus mediates between the conflicting requirements of maintaining voltage for functionality and enabling short-circuit for safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If spacers are added to prevent electronic coupling, then safety against tissue damage is improved, but device complexity increases

Engineering Contradiction:
Improvetissue damage preventionVSAvoidbattery structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent utilizes parameter changes in the spacer material's solubility properties. The spacer is made from a material that changes its physical state from insoluble (maintaining electrical isolation) to soluble (dissolving to enable short-circuit) based on the presence of aqueous fluids. This parameter change approach allows the safety mechanism to activate automatically without adding complex control systems, switches, or sensors.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The soluble spacer is designed as a simple, inexpensive, single-use component that performs its safety function and then dissolves away. Rather than creating a complex reusable safety system, the patent employs a disposable sacrificial element (the spacer) that eliminates itself after serving its protective purpose, thereby simplifying the overall device structure while ensuring safety.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The safety mechanism effectively short-circuits the battery when exposed to aqueous solutions, dropping the voltage to safe levels, thereby preventing tissue damage and electrolysis, ensuring consumer safety in case of accidental ingestion.

Implementation Method 1

The spacer is capable of undergoing a physical change in the presence of an aqueous solution such that electronic coupling between the electronic conductor and the other of the first and second poles can occur

Methodology Applied
Scientific EffectPhysical change in presence of aqueous solution:

Implementation Method 2

adapted to protect against tissue damage and/or electrolysis, when the battery is exposed to an aqueous solution or a wet tissue

Methodology Applied
Scientific EffectElectrolysis prevention: Electrolysis

Data Source

PatentEP4258459B1Battery with safety mechanism
Publication Date: 2025.03.26 DURACELL US OPERATIONS INC
  • EP4258459B1 patent drawingFigure 1
  • EP4258459B1 patent drawingFigure 2A~2B
  • EP4258459B1 patent drawingFigure 3

AI summary

Batteries with a safety mechanism adapted to protect against tissue damage and/or electrolysis when the battery is exposed to an aqueous solution or a wet tissue.