Lithium-ion Battery Additives for Capacity Fade Reduction

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Solution Overview

Problem

Conventional lithium-ion batteries experience capacity fade over their lifespan due to cell aging and cycling, which is undesirable for applications requiring consistent power, such as medical devices.

Innovation Solution

Incorporating a carbonaceous negative electrode and an electrolyte with additives like borane or borate compounds and alkenes, such as vinylene carbonate, to form an ionically conductive layer that reduces capacity fade.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lithium-ion batteries are used, then they can provide power for medical devices, but they exhibit capacity fade over the life of the battery due to cell aging and cycling

Engineering Contradiction:
Improvebattery capacity consistencyVSAvoidbattery life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical parameters of the electrolyte by introducing specific additives (borane/borate compounds and alkenes) to modify the SEI layer properties, thereby improving capacity retention and reducing degradation over the battery lifecycle

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses electrolyte additives as intermediary substances that mediate between the electrode and electrolyte interface, forming a protective SEI layer that prevents harmful interactions and reduces capacity fade during cycling

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the battery is designed for long life and resistance to capacity fade, then reliability improves, but the battery chemistry and electrolyte composition become more complex

Engineering Contradiction:
Improveresistance to capacity fadeVSAvoidelectrolyte composition
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies electrolyte composition parameters by adding specific chemical compounds (borane/borate at 0.1-5% and alkenes at 0.1-5%) to achieve improved performance while maintaining a relatively simple additive-based formulation approach

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 use of these additives significantly reduces capacity fade, leading to longer battery life and improved reliability, with a more tapered voltage/capacity curve for accurate end-of-life prediction.

Implementation Method 1

The first additive includes a borane or borate compound that acts as an ion receptor

Methodology Applied
Scientific EffectIon reception: Absorption (physical)

Implementation Method 2

the second additive includes an alkene capable of reacting on a surface of the negative electrode to form an ionically conductive layer

Methodology Applied
Scientific EffectSurface reaction: Chemical Bonding

Data Source

PatentEP1932203B1Lithium-ion battery
Publication Date: 2009.04.22 MEDTRONIC INC
  • EP1932203B1 patent drawingFigure 1
  • EP1932203B1 patent drawingFigure 2
  • EP1932203B1 patent drawingFigure 3~5

AI summary

A lithium-ion battery (100) includes a positive electrode (110), a negative electrode (120) comprising carbon, and an electrolyte (130) containing a first and second additive. The first additive includes a borane or borate compound that acts as an ion receptor and the second additive includes an alkene capable of reacting on a surface of the negative electrode (120) to form an ionically conductive layer.