Siloxane Electrolyte Additive for Thermal Safety in Lithium Batteries
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to ignition and explosion risks caused by side reactions between the cathode and electrolyte, and existing safety mechanisms often degrade the battery's quality and capacity.
Innovation Solution
Incorporating a high-safety additive with a unique chemical structure, featuring Si and ether groups with acryl functional groups, into the electrolyte to control reaction heat and prevent exothermic reactions, while maintaining lithium ion conductivity and battery quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic electrolyte additives are used to prevent heat emission, then safety is improved, but battery quality and capacity are degraded
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte additive by specifying precise molecular structures with Si-O backbone chains of particular lengths (n=2-10) and specific functional groups. This parameter optimization allows the additive to effectively suppress exothermic reactions while minimizing impact on battery capacity and charge-discharge characteristics.
Solution Approach 2:
The patent creates a composite electrolyte system by combining the novel siloxane-based additive (Formula 1 or 2) with conventional electrolyte components. This composite approach leverages the thermal stability of Si-O bonds while maintaining the electrochemical functionality of traditional electrolytes, achieving both safety improvement and quality preservation.
2Reliability
If cathode active materials are modified to control exothermic reactions, then safety is improved, but battery capacity and quality are degraded
Solution Approach 1:
The patent introduces the siloxane-based electrolyte additive as an intermediary substance that mediates between the cathode and the bulk electrolyte. This additive forms a protective interface layer that suppresses direct exothermic reactions between the cathode and electrolyte, controlling reaction heat without requiring modifications to the cathode active material itself, thereby preserving battery capacity.
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 additive effectively reduces calorific values and peak temperatures, enhancing thermal safety and preventing battery ignition and explosion, while minimizing quality degradation.
Implementation Method 1
a cathode shows a very unstable structure in a charged state, particularly at high temperature. The cathode having an unstable structure in a charged state causes a rigorous exothermic reaction with an electrolyte
Implementation Method 2
it is possible to control the reaction heat generated by such side reactions between a cathode and an electrolyte
Implementation Method 3
The additive effectively reduces calorific values and peak temperatures, enhancing thermal safety and preventing battery ignition and explosion
Data Source
Figure 1~2
AI summary
Disclosed is an electrolyte for a battery comprising: (a) an electrolyte salt; (b) an organic solvent; and (c) a functional electrolyte additive. An electrochemical device comprising the electrolyte is also disclosed. The additive used in the electrochemical device effectively controls the surface of a cathode active material, which otherwise causes side reactions with an electrolyte, due to the basic skeleton structure and polar side branches of the additive. Therefore, it is possible to improve the safety of a battery, while not adversely affecting the quality of a battery.