Button Cell Safety Layer That Shorts When Wet to Prevent Electrolysis
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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 comprising 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, effectively shorting the battery and reducing voltage below a threshold to prevent electrolysis, thereby protecting against 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 more convenient for consumer use, 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 that proactively prevents harmful effects before they occur. The safety layer is pre-installed on the battery surface and immediately activates upon contact with aqueous fluids, creating a protective barrier that prevents tissue damage before electrolysis can occur.
Solution Approach 2:
The safety layer acts as an intermediary between the battery and the human body. It is a conductive polymer composition that mediates the interaction by providing a controlled interface - non-conductive during normal use but becoming conductive when wet, thereby safely bridging the electrical circuit only when needed to prevent harm.
2Object-affected harmful factors
If the battery voltage is reduced to prevent electrolysis, then tissue damage is prevented, but normal battery performance is compromised
Solution Approach 1:
The safety layer exhibits dynamic electrical conductivity that changes based on environmental conditions. It transitions from a non-conductive state during normal battery operation to a conductive state when exposed to aqueous fluids, allowing the battery to maintain full power under normal conditions while automatically reducing effective voltage when swallowed.
Solution Approach 2:
The invention changes the electrical conductivity parameter of the safety layer in response to moisture exposure. The conductive polymer transitions from low conductivity (dry state) to high conductivity (wet state), thereby dynamically adjusting the electrical parameters to prevent electrolysis only when necessary.
3Object-affected harmful factors
If a safety layer is added to the battery, then protection against tissue damage is improved, but device complexity increases
Solution Approach 1:
The safety layer is composed of a composite material system including conductive polymers (such as polyacetylene, polypyrrole, or polythiophene), metal salts (such as lithium chloride, sodium iodide, or potassium bromide), and plasticizers. This composite structure provides both the protective function and the conditional conductivity in a single integrated layer.
Solution Approach 2:
The safety layer performs multiple functions simultaneously: it serves as a protective coating, a conditional conductor, a moisture sensor, and a voltage regulator. By combining these functions into a single multi-functional component, the design avoids adding separate complex systems while achieving comprehensive protection.
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 water-responsive safety layer effectively reduces the battery voltage to non-threatening levels upon exposure to aqueous solutions, preventing electrolysis and tissue damage, while maintaining normal battery performance under standard conditions.
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
the composite water-responsive safety layer further comprising at least one metal salt
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.