Sheet-Type Air Cell Electrolyte for Humidity-Stable Storage
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Solution Overview
Problem
Existing sheet-type air cells face issues with storage properties due to changes in humidity, leading to poor cell characteristics and electrolyte leakage, which current solutions do not adequately address.
Innovation Solution
A sheet-type air cell with an aqueous electrolyte solution containing a water-soluble high-boiling solvent and a thickening agent, along with a gelation accelerator, is used, maintaining a pH of 3 or more and less than 12, to reduce vapor pressure and increase viscosity, thereby enhancing storage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air holes are formed in the outer case to allow gas flow, then the cell can operate, but water evaporates and is dissipated to the outside causing poor storage properties
Solution Approach 1:
A hydrogel layer is introduced as an intermediary substance between the electrolyte solution and the external environment. This hydrogel acts as a mediator that allows necessary gas exchange while blocking water evaporation and preventing electrolyte leakage, thus resolving the contradiction between operational gas flow and storage stability
Solution Approach 2:
The electrolyte solution's physical parameters are changed by adding polyhydric alcohol to increase viscosity and reduce vapor pressure. This parameter modification decreases water evaporation rate while maintaining ionic conductivity, thereby improving storage properties without compromising cell operation
2Reliability
If polyhydric alcohol is added to reduce vapor pressure, then water evaporation is reduced, but the solution becomes more viscous affecting ion mobility
Solution Approach 1:
The concentration of polyhydric alcohol in the electrolyte solution is precisely optimized to achieve the desired balance. By controlling the amount of additive, the vapor pressure is sufficiently reduced to prevent evaporation while maintaining ion mobility within acceptable ranges for cell operation
3Reliability
If the negative electrode is gelatinized using cross-linked material, then water retention is improved, but the electrode structure becomes more complex
Solution Approach 1:
A hydrogel layer is used as an intermediary gelatinizing agent between the negative electrode and the electrolyte solution. This separate gel layer provides water retention benefits without requiring direct modification of the negative electrode structure, thus maintaining structural simplicity while achieving improved water retention
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 effectively maintains discharge characteristics over time, preventing electrolyte drying and leakage, resulting in improved storage properties and reduced environmental impact.
Implementation Method 1
polyhydric alcohol and/or its derivative may be added to the electrolyte solution to reduce the vapor pressure of the electrolyte solution
Implementation Method 2
the electrolyte further contains a thickening agent in an amount of 0.01 to 5% by mass of the total electrolyte
Implementation Method 3
the electrolyte further contains a gelation accelerator composed of a polyvalent metal salt
Data Source
AI summary
One aspect of the sheet-like air cell of the present invention includes a positive electrode having a catalyst layer, a negative electrode, a separator, and an electrolyte solution that are housed in a sheet-like outer case. The electrolyte solution is an aqueous solution that contains an electrolyte salt and has a pH of 3 or more and less than 12. The electrolyte solution contains a water-soluble high-boiling solvent with a boiling point of 150° C. or more in an amount of 1 to 30% by mass of the total solvent. Another aspect of the sheet-like air cell of the present invention includes a positive electrode having a catalyst layer, a negative electrode, a separator, and an electrolyte that are housed in a sheet-like outer case. The electrolyte is obtained by blending an electrolyte solution and a thickening agent. The electrolyte solution is an aqueous solution that contains an electrolyte salt and has a pH of 3 or more and less than 12.