Electrolyte Additive for High-Temperature Battery Stability
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Solution Overview
Problem
Lithium secondary batteries experience degradation in stability at high temperatures due to side reactions between electrode active materials and electrolyte components, leading to increased internal pressure and reduced performance.
Innovation Solution
Incorporating a compound with a functional group that can react with side reaction sites of negative electrode materials and another functional group that can react with moisture into the electrolyte to prevent decomposition of both negative and positive electrode materials, enhancing the battery's storage and cycle performance at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a battery is left at high temperature in a fully charged state, then electrochemical energy and thermal energy increase, but the SEI film breaks down and side reactions occur continuously between the anode surface and electrolyte, leading to increased internal pressure and reduced battery stability
Solution Approach 1:
The patent applies preliminary action by pre-forming a stable SEI film using a cyclic carboxylate additive before the battery is put into service. This pre-formed protective film prevents subsequent decomposition reactions at high temperatures, addressing the reliability issue before it occurs during storage.
Solution Approach 2:
The cyclic carboxylate compound acts as an intermediary substance that mediates between the electrolyte and the anode surface. It forms a protective interface layer that prevents direct contact and harmful reactions between the electrolyte and anode, thereby maintaining battery stability at high temperatures.
2Stress or pressure
If additives are added to the electrolyte to change the phase of the SEI film forming reaction, then internal pressure increase is inhibited, but the complexity of the electrolyte composition increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the electrolyte - specifically incorporating cyclic carboxylate compounds with defined molecular structures and concentrations. This changes the properties of the SEI film forming reaction to produce a more stable film that resists decomposition and pressure buildup.
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 significantly improves the battery's storage performance and cycle life by preventing decomposition of electrode materials, reducing output reduction at high temperatures, and maintaining lithium ion reversibility.
Implementation Method 1
a compound having a functional group which can react with a side reaction site of a negative electrode material in a secondary battery and a functional group which can react with moisture
Implementation Method 2
Lithium ions released from the cathode active material such as lithium metal oxide during an initial charging process of a lithium secondary battery move towards the anode active material such as graphite and then are intercalated between the layers of the anode active material
Implementation Method 3
The SEI film serves as an ion tunnel, which allows only lithium ions to pass. Due to the ion tunnel effects, the SEI film prevents an organic solvent having a high molecular weight, which moves together with lithium ions in the electrolyte from being intercalated into layers of the anode active material
Implementation Method 4
the electrolyte reacts with carbon of the anode active material on the surface of the anode active material such as graphite, thereby generating compounds such as Li 2 CO 3 , Li 2 O and LiOH. These compounds form a kind of Solid Electrolyte Interface (SEI) film on the surface of the anode active material such as graphite
Data Source
AI summary
Provided are an electrolyte which may prevent the degradation of the battery performance by including a functional group which can react with a side reaction site which is responsible for decomposition of negative electrode material components and a functional group which can react with moisture which is responsible for decomposition of positive electrode material components in an electrolyte of the battery to ensure the stability of the battery at high temperatures, and a secondary battery manufactured by adding the same. The present invention may employ a compound including a functional group which can react with a side reaction site of a negative electrode material and a functional group which can react with moisture to maximize the improvement of the storage performance of a secondary battery at high temperatures.