Mixed-Alkali Aqueous Electrolyte for Reflow-Stable Power Storage
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Solution Overview
Problem
Conventional aqueous electrolyte solutions used in power storage devices, such as capacitors and batteries, have a low boiling point, leading to explosion and structural damage during the reflow process at high temperatures, such as 250°C, used in surface-mount technology.
Innovation Solution
An aqueous electrolyte solution with a high boiling point is developed, comprising water as the solvent and cations of at least two types, specifically alkali metal cations such as potassium and lithium, with controlled molality to enhance stability and prevent vaporization during high-temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous electrolyte solution is used in power storage device, then manufacturing cost is reduced and capacity density is improved, but the electrolyte solution explodes during reflow process due to low boiling point
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous electrolyte solution by adding specific concentrations of lithium sulfate (0.1-10 mol/L) and potassium sulfate (0.1-10 mol/L) to modify the boiling point and thermal stability characteristics, allowing the solution to withstand reflow temperatures without exploding
Solution Approach 2:
The patent creates a composite electrolyte solution by combining water with multiple salts (lithium sulfate and potassium sulfate) in specific proportions, forming a stable composite system that maintains both the high conductivity of aqueous solutions and enhanced thermal stability for reflow process resistance
2Reliability
If aqueous electrolyte solution is used instead of non-aqueous electrolyte solution, then internal equivalent series resistance is reduced and capacity density is improved, but moisture content control becomes unnecessary which may affect performance
Solution Approach 1:
The patent modifies the chemical composition by incorporating specific concentrations of lithium sulfate and potassium sulfate in the aqueous electrolyte solution, which stabilizes the electrical performance and eliminates the need for strict moisture control during manufacturing
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 high-boiling-point aqueous electrolyte solution effectively prevents explosion and structural damage during the reflow process, ensuring the power storage device maintains its integrity and meets electrical charging standards.
Implementation Method 1
the electrolytic capacitor will be exploded due to the vaporization and expansion of the solution during the reflow process at 250° C.
Implementation Method 2
since the solvent is water and the conductivity of water is higher than that of organic solvents, the internal equivalent series resistance value is lower
Data Source
AI summary
An aqueous electrolyte solution, a power storage device filled with the aqueous electrolyte solution, and a manufacturing method of the power storage device are illustrated. The aqueous electrolyte solution comprises alkali metal cations of different types. With the hydration enthalpy of the alkali metal cations of the different types, a simulated boiling point of the aqueous electrolyte solution is higher than the 105° C. of the conventional aqueous electrolyte solution. After processed by the reflow furnace at 250° C., the power storage device has no cracks found on its appearance, which meets the electrical requirements, and overcomes the problem of bursting of the power storage device filled with conventional aqueous electrolyte solution. The housing of the power storage device adopts liquid crystal polymer, and/or the power storage device is firstly vacuumed and then packaged, therefore increasing coulombic efficiency of electrical testing of the power storage device.