Non-aqueous Electrolyte Additive for Battery Cycle Life

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Solution Overview

Problem

Non-aqueous electrolyte secondary batteries face challenges in improving high-temperature cycle characteristics while maintaining low initial irreversible capacity and high initial efficiency, with existing techniques failing to achieve these goals effectively.

Innovation Solution

A non-aqueous electrolytic solution containing a specific compound represented by a general formula, with a hexafluorophosphate as the electrolyte, and a combination of cyclic and linear carbonates as solvents, is used to enhance the battery's performance, including a negative electrode made of carbonaceous materials or silicon-containing materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing techniques are used to improve high-temperature cycle characteristics, then cycle characteristics are improved, but initial irreversible capacity increases and initial efficiency decreases

Engineering Contradiction:

Improvehigh-temperature cycle characteristicsVSAvoidinitial irreversible capacity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the chemical parameters of the electrolyte by introducing a specific compound with formula (1) containing carbonyl groups and heteroatoms (O, N, S, or F). This compound is used in a controlled amount of 0.01 to 4.5% by mass to modify the electrolyte composition, enabling the formation of a protective film that improves high-temperature cycle characteristics while controlling initial irreversible capacity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining the base non-aqueous electrolyte (containing cyclic carbonate, chain carbonate, and lithium salt) with the specific compound of formula (1). This composite approach allows the new compound to form a protective interface layer on the electrode surface, improving cycle characteristics without significantly increasing initial irreversible capacity when used in the specified concentration range

Inventive Principle:

Principle #40Composite materials

2Reliability

If the amount of specific compound is increased to improve cycle characteristics, then high-temperature cycle characteristics improve, but manufacturing cost increases

Engineering Contradiction:

Improvehigh-temperature cycle characteristicsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes the concentration parameter of the specific compound to a narrow range of 0.01 to 4.5% by mass. Within this range, the compound provides sufficient protective film formation to improve high-temperature cycle characteristics while minimizing the amount of expensive additive required, thus controlling manufacturing cost

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies a small but sufficient amount of the specific compound (0.01 to 4.5% by mass) to achieve the desired effect. This partial action approach avoids the need for large amounts of expensive additive while still obtaining significant improvement in high-temperature cycle characteristics

Inventive Principle:

Principle #16Partial or excessive action

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 solution results in a battery with small initial irreversible capacity, high initial efficiency, and excellent high-temperature cycle characteristics without compromising yield, improving both cycle and load discharge capacities.

Implementation Method 1

the specific compound is reacted on the electrode in the initial charging to form a film, improving the battery in initial charging/discharging efficiency

Methodology Applied

Scientific EffectFilm formation through electrochemical reaction: Electrodeposition

Implementation Method 2

a non-aqueous electrolytic solution comprising a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

a negative electrode made of carbonaceous materials or silicon-containing materials

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentEP3113274B1Non-aqueous electrolytic solution and non-aqueous electrolyte secondary battery using same

Publication Date: 2020.09.30 MITSUBISHI CHEM CORP

AI summary

A task of the present invention is to provide a non-aqueous electrolyte secondary battery which exhibits small initial irreversible capacity and high initial efficiency as well as excellent high-temperature cycle characteristics without sacrificing the yield of the battery. The non-aqueous electrolytic solution of the present invention is a non-aqueous electrolytic solution for use in a non-aqueous electrolyte secondary battery which comprises a positive electrode capable of having occluded therein and releasing metal ions, a negative electrode capable of having occluded therein and releasing metal ions, and a non-aqueous electrolytic solution comprising a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent, wherein the non-aqueous electrolytic solution contains a compound represented by the general formula (1) in an amount of 0.01 to 4.5% by mass, based on the mass of the non-aqueous electrolytic solution: wherein, in the general formula (1), n represents an integer of 1 to 4, and R1 to R3 represent predetermined groups.