Battery Cell Electrolyte Salt Composition for High Energy Density
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high energy density and safety performance, particularly due to the reduction in thickness of copper foils affecting heat dissipation and internal resistance, leading to deteriorated safety and power performance.
Innovation Solution
Incorporating a first electrolyte salt, such as lithium bis(fluorosulfonyl)imide, into the electrolyte solution with specific ratios and combinations of other electrolyte salts and additives to enhance ion dissociation energy and thermal stability, while optimizing current collector and active material densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of copper foil is reduced to improve energy density, then energy density is improved, but heat dissipation performance deteriorates and internal resistance increases
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific fluorinated cyclic carbonate additive that modifies the thermal properties and ion conduction characteristics of the electrolyte system, enabling high energy density to be achieved without compromising heat dissipation
Solution Approach 2:
The patent uses a composite electrolyte system combining fluorinated cyclic carbonate with other carbonate solvents and lithium salt additives to create a multi-component system that simultaneously provides high ionic conductivity and improved thermal stability, resolving the contradiction between thin foil energy density gains and heat dissipation losses
2Quantity of substance
If the thickness of copper foil is reduced to improve energy density, then energy density is improved, but power performance deteriorates due to increased internal resistance
Solution Approach 1:
The patent modifies the electrolyte composition by adding fluorinated cyclic carbonate which changes the electrical parameters including ionic conductivity and interfacial resistance, allowing thin copper foil to maintain low internal resistance and high power performance while achieving high energy density
3Quantity of substance
If conventional electrolyte salts are used to achieve high energy density, then energy density is improved, but thermal stability deteriorates and safety performance worsens
Solution Approach 1:
The patent changes the thermal stability parameters of the electrolyte system by introducing fluorinated cyclic carbonate additive which has superior thermal decomposition characteristics, raising the decomposition temperature and improving overall thermal stability while maintaining high energy density performance
Solution Approach 2:
The patent creates a composite electrolyte formulation combining fluorinated cyclic carbonate with conventional carbonate solvents and lithium salts, where the fluorinated component acts as a thermal stabilizer that prevents decomposition at elevated temperatures while the conventional components maintain ionic conductivity for high energy density
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 improves energy density and safety performance by maintaining optimal ratios of electrolyte salts and current collector thicknesses, reducing corrosion, and inhibiting adverse reactions, resulting in high energy density, safety, and power performance.
Implementation Method 1
The first electrolyte salt containing the R2 group has relatively large ion dissociation energy, and more active R1 ions can be dissociated
Implementation Method 2
The first electrolyte salt containing the R2 group has relatively high thermal stability, to help to improve overall heat resistance of the electrolyte solution
Data Source
AI summary
Provided are a battery cell, a battery, and a power consuming device. The battery cell includes: an electrode assembly, where the electrode assembly includes a positive electrode plate and a negative electrode plate; and an electrolyte solution, where the electrolyte solution includes a first electrolyte salt, and a molecular formula of the first electrolyte salt is:where R1 is one of Li, Na, K, Mg, and Al, R2 is at least one of element O, element S, element F, and C1-C3 alkyl or C1-C3 alkyl substituted with element F, and based on 100 parts by weight of the electrolyte solution, content W1 of the first electrolyte salt ranges from 2 parts by weight to 20 parts by weight. According to the technical solution of this application, energy density and safety performance of the battery can be improved.