SO2 Electrolyte Battery Cell With SBR-CMC Binder Stability
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Solution Overview
Problem
Rechargeable battery cells with SO2-based electrolytes face challenges such as hydrolysis issues due to residual water, poor solubility of conductive salts, and instability at high charging potentials, leading to oxidative decomposition and reduced energy density.
Innovation Solution
The use of inert binders like styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) for electrodes, combined with a conductive salt that forms a stable liquid solvate complex with SO2, ensuring high solubility and oxidation stability, and the application of these components in a way that maintains mechanical and electrochemical stability, even at high potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional organic electrolytes are used in lithium-ion cells, then the cells can operate at reasonable voltages, but the energy density is limited and safety risks arise from flammability
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by replacing organic solvents with inorganic components (LiClO4 in H2O-CH3OH mixture), fundamentally altering the electrolyte's properties to achieve non-flammability while maintaining ionic conductivity and enabling higher operating voltages for improved energy density
Solution Approach 2:
The use of inorganic electrolyte components creates an inherently safer, non-flammable environment within the battery cell, eliminating the fire hazards associated with conventional organic electrolytes while allowing operation at higher voltages that increase energy density
2Quantity of substance
If the cell voltage is increased to improve energy density, then more electrical energy is stored per unit volume, but the electrolyte undergoes oxidative decomposition
Solution Approach 1:
The patent changes the electrochemical stability window parameters by using an inorganic electrolyte system (LiClO4 in H2O-CH3OH) that maintains stability at higher voltages, allowing the cell to operate at elevated voltages for improved energy density without suffering from oxidative decomposition of organic solvents
Solution Approach 2:
The electrolyte uses a composite approach combining inorganic lithium perchlorate salt with a mixed solvent system of water and methanol, creating a stable electrolyte composition that resists oxidative decomposition at high voltages while maintaining ionic conductivity for high energy density operation
3Reliability
If conductive salts are added to improve ionic conductivity, then charge transport between electrodes is enhanced, but solubility issues arise with SO2-based electrolytes
Solution Approach 1:
The patent changes the solvent system parameters by replacing SO2 with a H2O-CH3OH mixture, which fundamentally improves the solubility parameters for lithium salts while maintaining the desired ionic conductivity, resolving the solubility stability issue that plagues SO2-based electrolytes
4Ease of manufacture
If residual water is present in the electrolyte, then the electrolyte can be easier to manufacture, but hydrolysis reactions occur reducing cell performance
Solution Approach 1:
The electrolyte uses a composite solvent system of water and methanol with lithium perchlorate salt, where the methanol component acts as a protective agent that prevents hydrolysis reactions of the lithium salt, allowing the presence of water without compromising electrolyte stability while maintaining ease of manufacture
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
This configuration results in a rechargeable battery cell with improved mechanical stability, high energy density, extended service life, and reduced self-discharge, capable of operating safely at higher voltages without electrolyte decomposition, while maintaining low vapor pressure and minimizing thermal runaway risks.
Implementation Method 1
the ions of the active metal migrate to the negative or positive electrode when charging or discharging the cell and take part in electrochemical processes there
Implementation Method 2
At least one ion of the conductive salt (anion or cation) is mobile in the electrolyte in such a way that ion conduction allows a charge transport to occur between the electrodes
Implementation Method 3
Above a certain upper cell voltage of the rechargeable battery cell, the electrolyte is electrochemically decomposed by oxidation
Implementation Method 4
When charging the lithium-ion cell, the ions of the active metal are deintercalated from the positive electrode and intercalated into the negative electrode
Data Source
AI summary
This disclosure relates to rechargeable battery cells containing an active metal, at least one positive electrode having a planar discharge element, at least one negative electrode having a planar discharge element, a housing and an SO2-based electrolyte containing a first conductive salt, wherein the positive and/or the negative electrode contains at least one first binder consisting of a polymer based on monomeric styrene and butadiene structural units, and at least one second binder from the group consisting of carboxymethyl celluloses.