Li-Ion Battery Electrolyte Using Vinylene Additives Against Swelling
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Solution Overview
Problem
Lithium-ion batteries face challenges in battery swelling during formation and high-temperature storage, and require improvements in discharge capacity and self-discharge performance, while existing additives like sulfonyl-containing compounds pose environmental concerns.
Innovation Solution
An electrolyte solution comprising an organic solvent with fluoroethylene carbonate (≥5%), a lithium salt, and additives with three or more carbon-carbon double bonds, such as specific compounds, replaces sulfonyl-containing compounds to enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfonyl-containing compounds are used as additives, then high-temperature storage performance is improved, but environmental protection issues arise
Solution Approach 1:
The patent changes the chemical structure parameters of the additive by replacing sulfonyl-containing compounds with compounds containing carbon-carbon double bonds (specifically vinylene groups). This structural parameter change maintains the protective film-forming capability on the anode while eliminating the environmental harm associated with sulfonyl groups, thus resolving the contradiction between performance and environmental protection.
Solution Approach 2:
The patent adopts readily available vinylene-containing compounds (such as vinylene carbonate or divinylene carbonate) as additives that can be easily synthesized and disposed of without environmental harm. These short-chain vinylene compounds serve the protective function temporarily during battery formation and storage, then degrade harmlessly, unlike persistent sulfonyl-containing compounds.
2Reliability
If conventional electrolyte solutions are used, then basic battery function is maintained, but battery swelling occurs during formation and high-temperature storage
Solution Approach 1:
The vinylene-containing additive performs preliminary protective action by forming a stable solid electrolyte interface (SEI) film on the anode surface during battery formation. This preliminary film prevents subsequent electrolyte decomposition and swelling during high-temperature storage, addressing the shape stability issue before it occurs.
Solution Approach 2:
The patent creates a composite protective film on the anode surface consisting of vinylene-derived compounds and other electrolyte components. This composite structure provides both mechanical stability (preventing swelling) and ionic conductivity (maintaining basic battery function), resolving the contradiction between shape stability and functional performance.
3Reliability
If existing additives are used, then electrolyte decomposition is inhibited, but discharge capacity and self-discharge performance need improvement
Solution Approach 1:
The vinylene-containing additive concentrates its protective effect locally at the anode surface where electrolyte decomposition most commonly occurs. By forming a targeted protective film only where needed, it prevents decomposition while leaving the bulk electrolyte composition optimized for high discharge capacity and low self-discharge performance.
Solution Approach 2:
The vinylene-containing compound performs multiple functions simultaneously: it forms protective films to inhibit electrolyte decomposition, stabilizes the anode surface to prevent swelling, and maintains ionic conductivity to support high discharge capacity. This multi-functionality resolves the contradiction between protection and performance.
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 reduces battery swelling, increases discharge capacity, and improves self-discharge performance at high voltage, while being environmentally friendly.
Implementation Method 1
During the charging process of lithium-ion batteries, such additives can form a solid electrolyte interface film on an anode and effectively inhibit the decomposition reaction of the electrolyte solution
Implementation Method 2
effectively inhibit the decomposition reaction of the electrolyte solution
Data Source
AI summary
An electrolyte solution of a lithium-ion battery and a lithium secondary battery. The electrolyte solution of a lithium-ion battery comprises an organic solvent, a lithium salt and an additive, wherein the organic solvent comprises fluorinated ethylene carbonate accounting for at least 5% of the total mass of the electrolyte solution, the additive comprises an additive A containing one or more compounds which have three or more carbon-carbon double bonds, and the electrolyte solution does not comprise a compound containing a sulfonyl group. The electrolyte solution of a lithium-ion battery is not only more environmentally friendly, but can also improve the swelling of the battery during the formation and high-temperature storage thereof, the discharge capacity of the battery, and the self-discharge performance of the battery under a high voltage.