BaTiO3-Modified Positive Electrode Material for Battery Safety

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Solution Overview

Problem

Lithium-nickel-cobalt-manganese composite oxides used in secondary batteries are prone to rapid heat generation and gas production upon external impact, leading to reduced stability and safety concerns, especially when stored at high temperatures.

Innovation Solution

Incorporating barium titanate (BaTiO3) into the lithium transition metal composite oxide during sintering to form a stable lithium transition metal composite oxide, which suppresses gas generation by solid-dissolving titanium within the oxide structure, enhancing thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium-nickel-cobalt-manganese composite oxide is used to achieve high battery capacity, then the battery capacity increases, but thermal stability deteriorates and gas generation occurs under external impact

Engineering Contradiction:

Improvebattery capacityVSAvoidthermal stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent uses a composite material system consisting of lithium-nickel-cobalt-manganese composite oxide combined with barium titanate (BaTiO3) and strontium titanate (SrTiO3). The BaTiO3 and SrTiO3 form a protective composite structure that suppresses thermal decomposition and gas generation while maintaining the high capacity characteristics of the lithium-nickel-cobalt-manganese oxide.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Barium titanate and strontium titanate act as intermediary substances that mediate between the lithium-nickel-cobalt-manganese composite oxide and the external environment. These intermediaries absorb thermal stress and prevent direct decomposition of the active material, thereby improving thermal stability without sacrificing battery capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If lithium-nickel-cobalt-manganese composite oxide is used to reduce cost compared to lithium-cobalt oxide, then manufacturing cost decreases, but gas generation increases under high temperature storage

Engineering Contradiction:

Improvemanufacturing costVSAvoidgas generation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and addresses the specific problem of gas generation by adding BaTiO3 and SrTiO3 as separate functional components. These extracted additives specifically target the gas generation issue while allowing the main lithium-nickel-cobalt-manganese composite oxide to maintain its cost advantage over lithium-cobalt oxide.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters by introducing BaTiO3 and SrTiO3 with specific ratios (BaTiO3: 0.01-0.5 mol%, SrTiO3: 0.01-0.5 mol%). This parameter modification suppresses gas generation during high-temperature storage while maintaining the cost-effectiveness of the lithium-nickel-cobalt-manganese base material.

Inventive Principle:

Principle #35Parameter changes

3Speed

If rapid heat generation occurs upon external impact, then battery capacity is quickly released, but thermal runaway and gas generation are triggered

Engineering Contradiction:

Improveheat generation rateVSAvoidthermal runaway

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent implements beforehand cushioning by incorporating BaTiO3 and SrTiO3 into the composite oxide structure before any thermal event occurs. These preemptively added compounds create a thermal buffer that cushions against rapid heat generation, preventing thermal runaway even when external impact causes quick capacity release.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 method effectively reduces gas generation and improves thermal stability of the positive electrode material, ensuring safer operation and longer cycle life of nonaqueous secondary batteries, even under high-temperature conditions.

Implementation Method 1

BaTiO3 releases oxygen through thermal decomposition at a temperature at which a lithium compound in the mixed material is melted

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

incorporating barium titanate when sintering the lithium transition metal composite oxide... titanium is solid-dissolved at a surface of particles or in the vicinity thereof and also at a center of particles

Methodology Applied

Scientific EffectSolid solution formation: Solid Solution Strengthening

Implementation Method 3

BaTiO3 releases oxygen through thermal decomposition at a temperature at which a lithium compound in the mixed material is melted

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11641015B2Method for producing positive electrode material for nonaqueous secondary battery

Publication Date: 2023.05.02 NICHIA CORP

AI summary

A method for producing a positive electrode material for a nonaqueous secondary battery includes the steps of mixing a compound containing lithium, a compound containing nickel and BaTiO3 to form a mixed material; and sintering the mixed material to form a lithium transition metal composite oxide.