Secondary Battery with C=S Electrolyte for High-Temp Stability
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Solution Overview
Problem
Lithium ion secondary batteries face significant capacity deterioration and volume changes during high-temperature charging and discharging, particularly when using silicon oxide as a negative electrode active substance, due to insufficient understanding of the interactions between the negative electrode, binder, electrolyte, and assembly structure.
Innovation Solution
A secondary battery design featuring a negative electrode formed by coating metal or metal oxide with carbon, using a polyimide or polyamide-imide binder, and an electrolyte liquid containing a compound with a C═S bond, which helps stabilize the electrode structure and improve battery performance at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide is used as a negative electrode active substance, then capacity is improved, but capacity deterioration at high temperature becomes significant
Solution Approach 1:
A compound containing a C═S bond is introduced as an intermediary substance in the electrolyte liquid. This compound mediates between the silicon oxide negative electrode and the electrolyte, forming a stable interface layer that prevents harmful reactions at high temperatures while maintaining lithium ion transport, thus resolving the contradiction between high capacity and high-temperature stability
Solution Approach 2:
The invention changes the chemical composition parameter of the electrolyte liquid by incorporating a compound with a C═S bond. This parameter change modifies the electrolyte's interaction with the negative electrode, creating a stable solid electrolyte interface (SEI) layer that suppresses capacity deterioration at high temperatures while preserving the high capacity characteristics of silicon oxide
2Quantity of substance
If high energy density is pursued, then battery performance is improved, but volume change of negative electrode increases
Solution Approach 1:
The invention changes the chemical environment parameter by introducing a C═S containing compound into the electrolyte. This modifies the interface properties between electrolyte and negative electrode, enabling better accommodation of volume changes during lithium insertion/extraction cycles while maintaining high energy density performance
3Productivity
If charging and discharging is carried out at high temperature, then rate performance is improved, but capacity deterioration accelerates
Solution Approach 1:
The C═S containing compound acts as a protective intermediary that forms a stable interface layer on the negative electrode. This layer allows efficient lithium ion transport at high temperatures (improving rate performance) while simultaneously protecting the electrode from thermal degradation (preserving cycle life), thus resolving the contradiction between productivity and reliability at high temperature
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 design enhances battery properties such as cycle life and rate performance at high temperatures by stabilizing the negative electrode and preventing gas accumulation, leading to a more efficient and long-lasting lithium ion secondary battery.
Implementation Method 1
the electrolyte liquid comprises a compound (A) having a C═S bond
Implementation Method 2
a carbon material (c) that can absorb and desorb lithium ion
Implementation Method 3
the negative electrode is formed by binding a negative electrode active substance on a negative electrode collector with a negative electrode binder
Data Source
AI summary
Provided is a secondary battery having a good battery property at a high temperature. A secondary battery according to an exemplary embodiment of the invention comprises a negative electrode and an electrolyte liquid; wherein the negative electrode is formed by binding a negative electrode active substance on a negative electrode collector with a negative electrode binder; and wherein the electrolyte liquid comprises a compound (A) having a C═S bond. In this embodiment, the negative electrode active substance is formed by covering at least one of a metal (a) that can be alloyed with lithium and a metal oxide (b) that can absorb and desorb a lithium ion with a carbon material (c). Alternatively, the negative electrode active substance comprises a metal (a) that can be alloyed with lithium and the negative electrode binder negative electrode is a polyimide or a polyamide-imide.