Lithium-Ion Battery Electrolyte Additives for Stable SEI and Power
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Solution Overview
Problem
Lithium-ion batteries face challenges in improving power performance and cycle life, with existing electrolyte solutions not adequately addressing issues of ion transmission, impedance, and gas production, which affect their efficiency and storage performance.
Innovation Solution
The introduction of specific additives in the electrolyte solution, which form a protective film on the negative electrode, improving ion transmission and power performance, and the use of a positive electrode sacrificing additive to mitigate gas production, while maintaining favorable conductivity and viscosity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used, then the battery can operate, but power performance and cycle life are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing specific additives (compounds with formula I containing R-COO-Li structures) to change the interfacial properties between electrolyte and electrode, thereby simultaneously improving power performance and cycle life without fundamental system changes
Solution Approach 2:
The additive compounds act as intermediaries that form protective interface films between the electrolyte and negative electrode, mediating the interaction to reduce impedance and improve ion transmission while maintaining stability over cycles
2Reliability
If additive content is increased to improve film formation, then protective film quality improves, but conductivity may deteriorate
Solution Approach 1:
The patent optimizes the concentration parameter of additives within a specific range (0.1-10% by mass) to achieve the right balance between film-forming capability and conductivity maintenance, avoiding both insufficient film formation and excessive viscosity increase
3Reliability
If W0/X1 ratio is increased to improve negative electrode protection, then cycling performance improves, but positive electrode effects may be neglected
Solution Approach 1:
The patent applies different considerations to different electrodes: the additive primarily targets negative electrode protection (local quality improvement) while the X2/W0 parameter ensures the positive electrode is not adversely affected, creating localized optimization without compromising overall system balance
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 proposed solution enhances the power and cycling performance of lithium-ion batteries, improves their service life, and reduces adverse effects on conductivity and storage performance, achieving stable and efficient operation.
Implementation Method 1
the additives shown in formula (I) are first reduced to a film on a surface of a negative electrode of the lithium-ion battery, forming an interfacial film with low impedance and high ion transmission capacity
Implementation Method 2
During the charge and discharge process, Li+ intercalates and deintercalates back and forth between the two electrodes: during charging, Li+ deintercalates from the positive electrode, intercalates through the electrolyte into the negative electrode
Implementation Method 3
An electrolyte solution is a carrier of ion transmission in the lithium-ion battery, serves to conduct ions between the positive electrode and the negative electrode of the lithium-ion battery
Data Source
AI summary
Provided are a lithium-ion battery, a battery module, a battery pack, and an electrical apparatus. The lithium-ion battery provided in the present application comprises one or more of additives shown in formula (I) in its electrolyte solution, and a ratio of a percentage mass content W0 of the additives shown in formula (I) in the electrolyte solution to a specific surface area X1 of a negative electrode active material in the negative electrode active material layer of the lithium-ion battery satisfies W0/X1=0.1−10. The additives shown in formula (I) are first reduced to a film on a surface of a negative electrode of the lithium-ion battery.