Button Cell Safety Layer That Shorts in Saliva
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Solution Overview
Problem
Small button cell batteries, particularly coin cells, pose a risk of tissue damage and electrolysis when swallowed due to their size and chemistry, which can lead to bodily harm, especially in infants and pets, as they can become lodged in the throat and cause electrolysis of body fluids and burning of esophageal/organ tissue.
Innovation Solution
A battery design incorporating a composite water-responsive safety layer made of a polymer material and metal salts that changes from a non-electronically conducting state to an electronically conducting state when exposed to an aqueous solution, such as saliva or stomach fluids, effectively shorting the battery and reducing voltage below levels that prevent electrolysis and tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a button cell battery is made small for portability, then it becomes easier to carry and use in compact devices, but it poses a greater risk of being swallowed and causing tissue damage
Solution Approach 1:
The patent applies preliminary action by incorporating a safety layer during battery manufacturing that proactively prevents tissue damage before it can occur. The safety layer is pre-positioned between the electrodes to immediately short-circuit the battery upon contact with body fluids, eliminating the need for reactive measures after ingestion
Solution Approach 2:
The safety layer acts as an intermediary component between the battery electrodes. It is a conductive material that normally remains inactive but activates upon contact with aqueous body fluids to create a low-resistance path, thereby mediating the interaction between the battery and body tissues to prevent harmful effects
2Object-affected harmful factors
If the battery voltage is reduced to prevent tissue damage, then safety is improved, but the battery's energy output and performance deteriorate
Solution Approach 1:
The patent applies local quality by creating a localized conductive path through the safety layer rather than reducing the overall battery voltage. The safety layer provides high conductivity only in the specific region where it contacts body fluids, while the rest of the battery maintains its normal voltage and energy output characteristics
Solution Approach 2:
The battery system is segmented into functional zones: the active battery components (electrodes, electrolyte) that provide energy, and the safety layer that provides protection. This segmentation allows the battery to deliver full power during normal operation while having a dedicated component that activates only when needed to prevent tissue damage
3Reliability
If a safety layer is added to the battery, then protection against tissue damage is improved, but the device complexity increases
Solution Approach 1:
The safety layer is implemented as a thin film or coating between the battery electrodes, rather than a bulky structural component. This thin-film approach provides the necessary safety function while minimizing impact on battery dimensions, capacity, and overall structural complexity
Solution Approach 2:
The safety layer utilizes composite material properties, combining conductive materials with materials that respond to body fluids (such as hydrophilic or pH-responsive materials). This composite approach enables the safety layer to remain inactive during normal use but activate automatically upon contact with aqueous environments, providing reliable protection without complex control mechanisms
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 composite safety layer effectively reduces the battery voltage to non-threatening levels upon exposure to aqueous solutions, preventing electrolysis and tissue damage, while maintaining normal performance under dry conditions, thus enhancing safety without affecting the battery's performance or storage stability in various humidity environments.
Implementation Method 1
the composite water-responsive safety layer being adapted to change from a non-electronically conducting state to an electronically conducting state when contacted with an aqueous solution
Implementation Method 2
these dangers can result in bodily harm, especially if the cell is swallowed unbeknownst to others around. And some of these button cell batteries can pose a relatively greater danger than others, which consumers may not fully appreciate. For example, coin cell batteries such as 2016 3V lithium cells and 2032 3V lithium cells, which are based on lithium-manganese dioxide chemistry, are sized such that they readily can become lodged in a human throat and thus cause electrolysis of body fluids and/or burning of esophageal/organ tissue
Data Source
AI summary
A battery cell comprising a composite water-responsive safety layer and/or composite water- and pH-responsive safety layer to protect against tissue damage and/or electrolysis, when the battery cell is exposed to aqueous solution or tissue, is provided. The composite water-responsive safety layer and/or composite water- and pH-responsive safety layer is adapted to change from a non-electronically conducting state to an electronically conducting state.