Non-conductive Pyrotechnic Mixture for ESD Safety
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Solution Overview
Problem
The existing pyrotechnic mixture zirconium/potassium perchlorate (ZPP) is electrically conductive, making it vulnerable to electrostatic discharge (ESD) and a safety hazard during handling and use in electro-explosive devices (EEDs), requiring additional safety measures and increasing manufacturing costs.
Innovation Solution
A co-precipitated mixture of dipotassium 5,5′-bistetrazole and potassium perchlorate (BI-820) is developed, which is non-conductive and stable at high temperatures, eliminating the need for pre-milling and reducing ESD sensitivity, and is used with ignition elements like bridgewires and thin film bridges in low energy EEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zirconium/potassium perchlorate (ZPP) mixture is used as pyrotechnic composition, then reliable ignition and high thermal conductivity are achieved, but electrical conductivity increases making it vulnerable to electrostatic discharge
Solution Approach 1:
The patent removes zirconium metal from the pyrotechnic composition entirely, replacing it with organic fuel components. This extraction of the conductive metal component eliminates the electrical conductivity problem while maintaining ignition reliability through the oxidizer-perchlorate and fuel-organic combination.
Solution Approach 2:
The patent creates a composite pyrotechnic composition combining organic fuels (such as HMX, RDX, or TNT) with potassium perchlorate oxidizer. This composite material achieves reliable ignition through the chemical reaction between fuel and oxidizer while remaining electrically non-conductive, thus resolving the contradiction between ignition reliability and ESD susceptibility.
2Power
If ZPP mixture is used in EEDs, then effective energy conversion is achieved, but additional safety measures and electrostatic protection are required increasing device complexity
Solution Approach 1:
By removing the conductive zirconium component from the pyrotechnic mixture, the patent eliminates the need for electrostatic protection measures such as grounding systems, spark gaps, and insulated handling equipment. This extraction simplifies the overall EED design while maintaining effective energy conversion through the organic fuel-potassium perchlorate reaction.
Solution Approach 2:
The patent changes the electrical conductivity parameter of the pyrotechnic composition from conductive (ZPP) to non-conductive (organic fuel/KP mixture). This parameter change fundamentally alters the safety characteristics, eliminating electrostatic discharge risks and simplifying device design without compromising power output or energy conversion efficiency.
3Reliability
If metal-based pyrotechnics like ZPP are used, then high thermal conductivity is achieved for no-fire safety, but post-combustion residue becomes conductive impacting battery lifetime
Solution Approach 1:
The patent extracts metal components from the pyrotechnic composition, replacing them with organic fuels. This eliminates conductive post-combustion residues that would otherwise form on battery contacts, thereby preserving battery lifetime while maintaining no-fire safety through the thermal properties of the organic oxidizer system.
Solution Approach 2:
The patent changes the chemical composition parameters from metal-based to organic-based pyrotechnics. This parameter change affects both the combustion residue properties (non-conductive) and the thermal conductivity characteristics, maintaining safety while extending battery operational lifetime by preventing conductive residue formation.
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
BI-820 provides reliable ignition with high thermal stability and reduced ESD susceptibility, simplifying device design, reducing manufacturing costs, and ensuring safer handling by being non-corrosive and non-conductive before and after ignition.
Implementation Method 1
ZPP is typically activated by electrically heating an ignition element, such as a thin metal bridgewire
Implementation Method 2
Energy transfer from the resistive wire to the ZPP charge causes it to ignite
Implementation Method 3
This is partially due to the high thermal conductivity of ZPP mixtures that effectively move heat away from the bridgewire and into the bulk material under no-fire conditions
Data Source
AI summary
Described are energetic compositions formed of a 5,5′-bistetrazole salt and a perchlorate salt, in which the energetic composition is a co-precipitated product. The 5,5′-bistetrazole salt and the perchlorate salt can be dipotassium 5,5′-bistetrazole and potassium perchlorate. The energetic composition can have a particle size distribution between 1-50 micron and/or a mean volume diameter of less than 30 micron. In a low energy electro-explosive device, an ignition element is at least partially surrounded by an acceptor formed of this energetic composition, and the ignition element can be a bridgewire, a thin film bridge, a semiconductor bridge, or a reactive semiconductor bridge.