Electrolytic solution and non-aqueous electrolytic solution secondary battery
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Solution Overview
Problem
Conventional lithium secondary batteries experience a significant decrease in discharge capacity under high-current conditions due to the negative electrode reacting with the non-aqueous electrolytic solution during storage, especially when exposed to high temperatures, which affects their storage properties.
Innovation Solution
An electrolytic solution containing a carboxylic acid ester and a hydroxy group-containing or ether group-containing compound, with specific concentration and ratio limits, is used to stabilize the electrolyte and prevent capacity loss under high-current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional small batteries are merely enlarged for large battery applications, then battery size increases, but output performance becomes insufficient
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing a specific cyclic carboxylate component and controlling the ratio of cyclic carbonate to chain carbonate within 5:95 to 45:55 by volume. This parameter optimization enables high output performance in large-scale batteries without merely enlarging conventional designs.
Solution Approach 2:
The patent uses a composite electrolyte system combining cyclic carbonate (EC, PC) and chain carbonate (DMC, DEC, EMC) with cyclic carboxylate (GBL, GVL). This composite approach creates synergistic effects that deliver both large capacity and high output performance simultaneously.
2Power
If batteries are designed for high output performance, then power delivery improves, but battery life decreases
Solution Approach 1:
The patent optimizes electrolyte composition parameters, specifically setting cyclic carboxylate content at 5-80 vol% and cyclic to chain carbonate ratio at 5:95 to 45:55. These parameter adjustments enable the battery to achieve both high output performance and extended cycle life through improved electrochemical stability.
Solution Approach 2:
The patent converts the potential harm of high current density operation (which typically reduces battery life) into a benefit by using cyclic carboxylate additives that form protective SEI layers. These layers prevent electrode degradation during high-power operation, thereby extending battery life while maintaining high output performance.
3Duration of action of moving object
If batteries are designed for long cycle life, then durability improves, but discharge capacity decreases
Solution Approach 1:
The patent adjusts electrolyte composition parameters to achieve optimal balance between cycle life and discharge capacity. By controlling cyclic carboxylate content at 5-80 vol% and optimizing the cyclic-to-chain carbonate ratio, the battery achieves both long cycle life and high discharge capacity through improved electrode electrolyte interface stability.
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 electrolytic solution maintains high capacity retention even under high-current conditions and at various temperatures, including low temperatures, by forming a stable solid electrolyte interphase film on the negative electrode.
Implementation Method 1
a non-aqueous electrolytic secondary battery including a positive electrode, a negative electrode, and a lithium ion conductor
Implementation Method 2
Electrolytic solution and non-aqueous electrolytic solution secondary battery
Data Source
AI summary
The present invention provides an electrolytic solution that is less likely to cause a decrease in discharge capacity even under high-current conditions and enables high capacity retention, and a non-aqueous electrolytic solution secondary battery including the electrolytic solution. Provided is an electrolytic solution containing a carboxylic acid ester; and a hydroxy group-containing compound and/or an ether group-containing compound, the electrolytic solution containing the hydroxy group-containing compound and/or the ether group-containing compound in an amount of 50 mass ppm or less.