Supercapacitor Ionic Liquid Electrolyte Thermal Shock Resistance
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Solution Overview
Problem
Supercapacitors face performance impairment and potential destruction due to thermal shock during manufacturing processes like reflow soldering, as they are susceptible to rapid temperature changes, leading to electrolyte expansion or vaporization, which affects their energy storage capacity and reliability.
Innovation Solution
A supercapacitor design featuring a pair of electrodes with a mixture of carbon particles, a porous separator, and an ionic liquid electrolyte that includes specific cations and anions, providing high conductivity and stability at various temperatures, including sub-zero and high thermal shock conditions, while maintaining low thermal conductivity packaging to minimize heat-induced degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolytes are used in supercapacitors, then manufacturing cost is reduced, but thermal stability deteriorates causing electrolyte vaporization during reflow soldering
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using ionic liquids with specific cations (imidazolium, pyridinium, pyrrolidinium, piperidinium, phosphonium, or sulfonium) and anions (BF4-, PF6-, CF3SO3-, N(CN)2-, N(CF3SO2)2-). This composition change enables the electrolyte to withstand reflow soldering temperatures without vaporization while maintaining electrochemical stability.
Solution Approach 2:
The patent employs composite ionic liquid electrolytes formed by combining specific cations and anions to create a stable compound that resists thermal degradation. The composite structure of the ionic liquid provides both thermal stability during manufacturing and electrochemical stability during operation, solving the contradiction between manufacturability and reliability.
2Quantity of substance
If high surface area carbon particles are used to increase energy storage capacity, then capacitance increases, but internal resistance increases reducing power delivery
Solution Approach 1:
The patent optimizes the particle size parameter of the carbon material to a specific range of 0.001 to 0.05 micrometers. This size optimization balances the competing requirements: small enough to provide high surface area for energy storage (capacitance) while large enough to maintain low internal resistance for effective power delivery. The ionic liquid electrolyte further enhances ion transport at these optimized particle surfaces.
3Productivity
If rapid cooling is applied after reflow soldering, then manufacturing cycle time is reduced, but thermal shock damages the supercapacitor
Solution Approach 1:
The patent applies beforehand cushioning by using ionic liquid electrolytes that are pre-selected for their high thermal stability and resistance to thermal shock. This protective property is built into the electrolyte composition before manufacturing, allowing the supercapacitor to withstand rapid cooling after reflow soldering without damage, thus enabling faster manufacturing cycles while maintaining reliability.
4Quantity of substance
If electrode coating thickness is increased to improve capacitance, then energy storage increases, but internal resistance increases reducing efficiency
Solution Approach 1:
The patent optimizes the electrode coating thickness parameter to balance capacitance and internal resistance. Combined with the use of ionic liquid electrolytes that provide superior ionic conductivity, this optimization allows thicker coatings to achieve higher capacitance while the ionic liquid minimizes the increase in internal resistance, thereby reducing energy loss and maintaining efficiency.
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 solution enables supercapacitors to withstand high thermal shock and maintain performance across a broad range of operating temperatures, ensuring stability and reliability in demanding environments, with improved energy storage capacity and reduced degradation rates.
Implementation Method 1
an electrolyte for wetting the separator wherein the electrolyte comprises an ionic liquid
Implementation Method 2
a porous separator positioned between the facing surfaces of the at least one pair of electrodes
Implementation Method 3
providing high conductivity and stability at various temperatures, including sub-zero and high thermal shock conditions
Implementation Method 4
at least one pair of electrodes having a mixture of carbon particles on facing surfaces
Data Source
AI summary
A supercapacitor capable of withstanding SMT manufacturing conditions includes at least one pair of electrodes having a mixture of carbon particles preferably in a CMC binder on facing surfaces of the at least one pair of electrodes; a porous separator, preferably polyimide, positioned between the facing surfaces of the at least one pair of electrodes; and an electrolyte for wetting the separator wherein the electrolyte includes an ionic liquid, such as EMITSFI, and optionally a solvent such as PC, GBL or glutaronitrile.