Boron Compound Electrolyte for Secondary Battery Resistance

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Solution Overview

Problem

Secondary batteries used in electric vehicles and hybrid vehicles face challenges with high initial DC resistance and increased resistance over time, which deteriorates output characteristics and running performance.

Innovation Solution

A non-aqueous electrolyte solution for secondary batteries containing a boron compound represented by a specific formula, which reduces initial DC resistance and suppresses resistance increase over time, is used, along with additional components like carbonate compounds and cyclic sulfonic acid esters to enhance ion conductivity and battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolyte solutions are used, then basic battery function is maintained, but DC resistance increases over time and output characteristics deteriorate

Engineering Contradiction:
Improveoutput characteristicsVSAvoidDC resistance stability
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by introducing a specific boron compound (Formula 1) with defined molecular structure and concentration range (0.01-10% by mass). This parameter change transforms the electrolyte's resistance stability characteristics, enabling both low initial DC resistance and suppressed resistance increase over time, thereby resolving the contradiction between reliability and duration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining the boron compound (Formula 1) with conventional electrolyte components (lithium salt, cyclic carbonate, chain carbonate). This composite material approach synergistically improves output characteristics while maintaining DC resistance stability over time, addressing both aspects of the technical contradiction simultaneously.

Inventive Principle:
Principle #40Composite materials

2Power

If high current discharge is required for vehicle acceleration, then output power increases, but DC resistance increases and efficiency decreases

Engineering Contradiction:
Improveoutput powerVSAvoidenergy loss due to resistance
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent modifies the electrolyte's electrical parameters by incorporating the boron compound (Formula 1) at optimized concentrations. This changes the electrolyte's conductivity and resistance characteristics, enabling high power delivery during acceleration while minimizing energy loss to resistance, thus resolving the contradiction between power output and energy efficiency.

Inventive Principle:
Principle #35Parameter changes

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 improved output characteristics, storage characteristics, and reduced DC resistance, leading to better performance and longevity of secondary batteries in vehicles.

Implementation Method 1

the electrolyte contained in the non-aqueous electrolyte solution transfers ions between a positive electrode and a negative electrode

Methodology Applied
Scientific EffectIon conductivity enhancement: Conduction (electrical)

Implementation Method 2

the non-aqueous electrolyte solution is preferably a liquid having a high ion movement speed, and specifically, is demanded to have a low viscosity and to be a liquid that readily causes mass transfer by diffusion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3373378B1Nonaqueous electrolyte solution for secondary batteries, and secondary battery
Publication Date: 2020.04.29 MITSUI CHEMICALS INC
  • EP3373378B1 patent drawingFigure 1
  • EP3373378B1 patent drawingFigure 2
  • EP3373378B1 patent drawing

AI summary

A non-aqueous electrolyte solution for a secondary battery, including a boron compound represented by Formula (1). In Formula (1), R represents an alkyl group having from 1 to 12 carbon atoms, an alkenyl group having from 2 to 12 carbon atoms, or a group represented by Formula (2). In Formula (2), each of R1 to R3 independently represents a hydrogen atom, a halogen atom, an alkyl group having from 1 to 12 carbon atoms, an alkenyl group having from 2 to 12 carbon atoms, or an aryl group having from 6 to 12 carbon atoms, and * represents a bonding site with an oxygen atom in Formula (1).