SO2 Electrolyte Rechargeable Cell With Soluble Stable Conducting Salts
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Solution Overview
Problem
Existing rechargeable lithium-ion cells with organic electrolytes face stability issues, safety risks, and reduced energy density due to oxidative and reductive decomposition, leading to thermal runaway and increased production costs, while SO₂-based electrolytes suffer from low solubility of conducting salts and reactions with leakage elements.
Innovation Solution
A rechargeable battery cell with an SO₂-based electrolyte containing specific conducting salts and leakage elements made of aluminum or copper, ensuring high solubility, stability, and resistance to oxidative and reductive decomposition, with a wide electrochemical window and improved energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic electrolytes are used in lithium-ion cells, then the cells can operate at reasonable voltages, but the electrolyte undergoes oxidative and reductive decomposition leading to thermal runaway and reduced stability
Solution Approach 1:
The patent replaces organic electrolytes with an SO2-based electrolyte system that creates a chemically inert environment. The SO2 acts as a stable solvent that does not undergo decomposition reactions, eliminating the harmful oxidative and reductive decomposition that occurs with organic electrolytes. This inert environment prevents thermal runaway and significantly improves cell stability.
2Reliability
If SO2-based electrolytes are used, then stability and safety are improved, but the solubility of conducting salts is low
Solution Approach 1:
The patent uses a composite electrolyte system comprising SO2 as the primary solvent combined with specific conducting salts (lithium tetrafluoroborate LiBF4, lithium hexafluorophosphate LiPF6, or lithium perchlorate LiClO4). This composite approach allows the SO2 to provide stability and safety while the selected conducting salts maintain adequate solubility and ionic conductivity, resolving the contradiction between stability and salt solubility.
3Reliability
If SO2-based electrolytes are used, then safety is improved, but reactions with leakage elements occur
Solution Approach 1:
The patent changes the electrochemical parameters of the system by using SO2 as the electrolyte solvent, which has a wide electrochemical stability window. This parameter change prevents reactions with leakage elements because SO2 remains stable at the operating voltages, unlike organic electrolytes that decompose and react with electrode materials and leakage elements.
4Ease of manufacture
If conventional electrolytes are used, then production costs are reduced, but energy density is reduced due to safety measures
Solution Approach 1:
The SO2-based electrolyte creates an inherently safe inert environment that eliminates the need for additional safety measures such as flame retardants, pressure relief valves, and thermal management systems required for organic electrolytes. This allows the battery design to focus on maximizing energy density without compromising safety, while the simplified design actually reduces production costs.
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 provides a rechargeable battery cell with enhanced stability, safety, and energy density, supporting high voltage operation and extended lifespan with minimal self-discharge and resistance to thermal and mechanical stress.
Implementation Method 1
At least one ion of the conducting salt (anion or cation) is mobile enough in the electrolyte to allow charge transport between the electrodes via ionic conduction
Implementation Method 2
The conducting salt is dissolved in the electrolyte and exhibits very good solubility therein. It can form a liquid solvate complex with the gaseous SO2
Implementation Method 3
Above a certain upper cell voltage, the electrolyte undergoes oxidative electrochemical decomposition. This process often leads to the irreversible destruction of electrolyte components
Implementation Method 4
Reductive processes can also decompose the electrolyte below a certain lower cell voltage
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a rechargeable battery cell (2, 20, 40) comprising an active metal, at least one positive electrode (4, 23, 44) with a leakage element (26), at least one negative electrode (5, 22, 45) with a leakage element (27), a casing (1, 28) and an electrolyte, wherein the leakage element (26) of the positive electrode (4, 23, 40) and the leakage element (27) of the negative electrode (5, 22, 45) are independently formed from a material selected from the group consisting of aluminum and copper, and wherein the electrolyte is SO2-based and contains at least one first conducting salt having formula (I), where M is a metal selected from the group consisting of alkali metals, alkaline earth metals, metals of Group 12 of the periodic table of elements and aluminum; x is an integer from 1 to 3;the substituents R1, R2, R3 and R4 are independently selected from the group consisting of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C6-C14 aryl, and C5-C14 heteroaryl; and where Z is aluminum or boron.