Button Cell Fuse Structure for Ingestion-Induced Circuit Break
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Solution Overview
Problem
Single cell cylindrical batteries, such as button cells, pose a risk of severe injury or death when ingested due to potential short circuits in the digestive or respiratory tracts, as they can cause local chemical reactions leading to tissue damage, and existing safety measures like adhesive stickers or thermal fuses are inadequate.
Innovation Solution
Incorporating an electrical fuse made of dielectric material with a conductive element that loses conductivity in a controlled manner upon ingestion, such as a saliva-soluble insulator or memory metal, to break the circuit and prevent continuous discharging, thereby reducing the risk of injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If button cells are made mechanically interchangeable and compact, then ease of operation and portability are improved, but the risk of ingestion and severe injury increases
Solution Approach 1:
An electrical fuse is introduced as an intermediary safety component between the electrodes and terminals. This fuse contains a water-soluble or saliva-soluble insulating material that maintains electrical isolation during normal use but dissolves upon ingestion, allowing the circuit to break and prevent harmful continuous discharge and tissue damage
Solution Approach 2:
The electrical properties of the battery circuit are changed conditionally through the use of water-soluble insulating material in the fuse. The fuse maintains high electrical resistance during normal operation but transitions to low resistance (circuit break) when exposed to water or saliva, fundamentally altering the electrical parameter based on environmental conditions
2Reliability
If adhesive stickers are used to seal electrodes, then short-circuit prevention is improved, but reliability upon ingestion deteriorates as the seal is never electrically complete
Solution Approach 1:
The electrical fuse serves as a more reliable intermediary safety device compared to adhesive stickers. It provides intentional electrical isolation through the water-soluble insulating material that remains effective until ingestion occurs, at which point the dissolution mechanism actively breaks the circuit rather than relying on an already-imperfect adhesive seal
Solution Approach 2:
The fuse is pre-configured with water-soluble insulating material that is designed to dissolve upon contact with water or saliva. This preliminary arrangement ensures that the safety mechanism is already in place and will automatically activate upon ingestion, rather than relying on adhesive seals that are never fully effective
3Temperature
If thermal fuses are used for safety, then response to overheating is improved, but effectiveness against ingestion-induced short circuits deteriorates
Solution Approach 1:
The safety mechanism responds to a different physical parameter - electrical resistance changes due to water/saliva dissolution - rather than temperature. The water-soluble insulating material in the fuse transitions from insulating to conductive state when dissolved, breaking the circuit in response to ingestion rather than overheating
Solution Approach 2:
The thermal fuse mechanism (temperature-based) is replaced with an electrical fuse mechanism based on water/saliva dissolution. This substitution changes the triggering condition from thermal energy to chemical dissolution, making the safety device effective against ingestion-induced short circuits while maintaining protection against abnormal discharge
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 electrical fuse effectively interrupts the current flow upon ingestion, significantly reducing the risk of injury and preventing most serious harm by breaking the circuit quickly, thus making the battery safer without compromising its normal functioning.
Implementation Method 1
the at least one fuse comprises a water-soluble or saliva-soluble insulating material, in particular a biopolymer
Implementation Method 2
a memory metal, in particular a shape memory alloy, which is not in contact with the at least one negative terminal and the at least one positive terminal at a temperature below 30° C., preferably at a temperature below 25° C., and which is in contact with the at least one negative terminal and the at least one positive terminal at a temperature above 30° C., preferably at a temperature above 35° C.
Data Source
AI summary
The present invention relates to a single cell cylindrical battery, such as a button cell or a button battery, that can be regarded to have the shape of a slice of a cylinder, and to a method preventing upper digestive and upper respiratory tract injury after accidental ingestion of the single cell cylindrical battery. It is noted that in some case ingestion has even led to the death in particular of children or small size adults, or people with a mental limitation, or people with a prior narrowing of structures in which the battery can be lodged. The structures in which the battery can be lodged are both the pharyngeal, upper digestive and upper respiratory tracts. As ingestion itself can not always be prevented, a relatively safe battery has been developed, which mitigates problems associated with ingestion.