Eutectic KOH-NaOH Electrolyte for Thermal Battery Activation
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Solution Overview
Problem
Conventional thermal batteries have limited low-temperature performance and short shelf life, making them unsuitable for applications requiring reliable power at lower temperatures without the need for pyrotechnic activation mechanisms.
Innovation Solution
A eutectic formulation of KOH and NaOH is used as an electrolyte in thermal batteries, with a melting point ranging from 180°C to 290°C, allowing for activation at high temperatures without external stimuli, and can be incorporated into anodes and cathodes with various binders and materials to enhance conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal battery electrolytes (LiCl-KCl eutectic with binder) are used, then the battery can maintain structural integrity and prevent short circuits, but the ionic conductivity is reduced due to binder resistance
Solution Approach 1:
The patent removes the binder material from the electrolyte composition entirely, using only the LiCl-KCl eutectic mixture. This extraction eliminates the source of ionic resistance while maintaining structural integrity through alternative means (electrolyte saturation and capillary action in porous separators), thereby resolving the contradiction between structural reliability and ionic conductivity.
Solution Approach 2:
The patent employs porous separators that utilize capillary action to contain and distribute the molten electrolyte. The porous structure provides both mechanical support for structural integrity and facilitates ionic transport through the electrolyte, eliminating the need for resistive binder materials while maintaining both reliability and conductivity.
2Power
If pyrotechnic activation mechanisms are used to initiate battery operation, then the battery can provide high power output, but the shelf life is limited and the system becomes more complex
Solution Approach 1:
The patent changes the activation temperature parameter by using an electrolyte with a lower melting point (LiCl-KCl eutectic at 600°C) compared to conventional high-temperature electrolytes. This parameter change allows activation at lower temperatures, extending shelf life and enabling alternative activation methods that do not require pyrotechnic mechanisms, while still achieving the necessary power output.
Solution Approach 2:
The patent removes the pyrotechnic activation mechanism from the battery system entirely. By using an electrolyte that activates at lower temperatures through simpler thermal or electrochemical means, the complex pyrotechnic components are extracted, thereby extending shelf life and reducing system complexity while maintaining power output capability.
3Stability of the object's composition
If binder materials are included in the electrolyte to prevent dispersion, then the electrolyte remains contained within the battery, but the impedance of the battery increases
Solution Approach 1:
The patent extracts the binder material from the electrolyte composition, eliminating the source of increased impedance. The electrolyte containment stability is maintained through alternative mechanisms including capillary action in porous separators and proper electrolyte saturation, thereby resolving the contradiction between composition stability and impedance reduction.
Solution Approach 2:
The patent uses the porous separator structure to replicate the containment function previously provided by binders. The separator's porous network captures and holds the molten electrolyte through capillary forces, providing the same containment stability without the harmful impedance effect of organic binder materials.
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 eutectic electrolyte formulation enables thermal batteries to operate effectively at lower temperatures, extending their shelf life and eliminating the need for pyrotechnic activation, making them suitable for diverse applications including downhole mining operations.
Implementation Method 1
a eutectic formulation of KOH and NaOH used as an electrolyte in an electrolyte-separator according to claim 1, in an anode, and/or in a cathode is provided that imparts the reliability and performance of an SOZ battery to thermal batteries
Implementation Method 2
The eutectic formulation may comprise about 57 wt % KOH and about 43 wt % NaOH
Implementation Method 3
a binder (such as MgO, fumed silica or kaolin), which assists in containing the electrolyte within the thermal battery assembly upon melting, such as by capillary action, surface tension, or both
Implementation Method 4
a binder (such as MgO, fumed silica or kaolin), which assists in containing the electrolyte within the thermal battery assembly upon melting, such as by capillary action, surface tension, or both
Implementation Method 5
the binder materials tend to be relatively resistant to ionic conduction and thus inclusion of the binder may increase the impedance of the battery
Data Source
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AI summary
A eutectic formulation of KOH and NaOH is used as an electrolyte or an electrolyte-separator. An anode, and/or a cathode can contain the eutectic formulation of KOH and NaOH. A battery can contain an electrolyte-separator, an anode, and/or a cathode with the eutectic formulation of KOH and NaOH. The electrolyte in the electrolyte-separator can have a melting point from about 170°C to about 300°C making it suitable for use in a thermal battery that does not require a pyrotechnic device for certain high-temperature applications.