Battery Electrolyte Composition for High-Temperature Cathode Stability
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Solution Overview
Problem
Lithium-ion batteries face safety issues due to the instability of the positive electrode active material at high temperatures, leading to metal ion dissolution and deposition on the negative electrode, which causes a continuous increase in battery temperature and potential safety accidents.
Innovation Solution
A battery electrolyte solution comprising an organic solvent, 1,3-propane sultone, a nitrile substance, and an electrolyte salt, where the percentages of these components are optimized to form a robust composite solid electrolyte interface (CEI) film on the positive electrode plate, reducing side reactions and metal ion deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame retardant is added to the electrolyte solution to improve safety performance at high temperature, then safety performance is improved, but other performance of the battery deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by introducing specific additives (cyclic carboxylate and/or cyclic carbonate) with controlled concentration ranges (0.1-5 wt% for cyclic carboxylate, 0.1-10 wt% for cyclic carbonate). This parameter optimization allows the electrolyte to form protective films that improve high-temperature safety while maintaining acceptable electrochemical performance, thus resolving the contradiction between safety improvement and performance degradation
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic carboxylate, cyclic carbonate, chain carbonate, and lithium salt. This composite formulation works synergistically where the cyclic carboxylate and cyclic carbonate form stable protective films on electrodes, improving safety without significantly compromising the electrochemical performance provided by the chain carbonate and lithium salt components
2Temperature
If the positive electrode active material is used at high temperature, then battery operation is maintained, but metal ions are dissolved and deposited on the negative electrode causing safety accidents
Solution Approach 1:
The patent applies preliminary action by having the cyclic carboxylate and cyclic carbonate additives proactively form protective films on the electrode surfaces during initial cycles or low-temperature operation. These pre-formed films act as barriers that prevent metal ion dissolution and deposition when the battery subsequently operates at high temperatures, thus preventing safety accidents before they occur
Solution Approach 2:
The cyclic carboxylate and cyclic carbonate act as intermediary substances that form protective interface layers between the positive electrode active material and the electrolyte. These intermediary films prevent direct harmful interactions at high temperatures, blocking the dissolution of metal ions while still allowing lithium ion transport, thus maintaining safety stability during high-temperature operation
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 optimized electrolyte solution enhances the peeling strength of the positive electrode plate, reduces internal resistance, and improves high-temperature and safety performance of the battery without degrading other performance metrics, thereby ensuring low-temperature and long-cycling performance.
Implementation Method 1
This destroys a structure of a solid electrolyte interface (Solid Electrolyte Interface, SEI) film on the surface of the negative electrode plate
Implementation Method 2
A relatively robust composite solid electrolyte interface (Cathode Electrolyte Interface, CEI) film can be formed on a surface of the positive electrode plate
Implementation Method 3
a battery electrolyte solution and a preparation method of the battery electrolyte solution
Data Source
AI summary
Disclosed are a battery electrolyte solution and a battery. The battery electrolyte solution includes an organic solvent, an additive, and an electrolyte salt, the organic solvent includes an ethyl group solvent, and the additive includes 1,3-propane sultone and a nitrile substance. The electrolyte solution is in contact with a positive electrode plate. Percentages of the ethyl group solvent, the 1,3-propane sultone, and the nitrile substance in a total mass of the electrolyte solution are configured as follows: 0.45−N3≤A+B2+C2≤516−N3. N denotes a peeling strength value of the positive electrode plate, in a unit of gf/mm, A, B, and C denotes a percentage of the mass of the ethyl group solvent, 1,3-propane sultone, and the nitrile substance in the total mass of the electrolyte solution.