Lithium Secondary Battery Electrode Composition for Low Gas Swelling

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Solution Overview

Problem

Lithium secondary batteries with high nickel content positive electrodes and silicon-based negative electrodes face issues of gas emission and volume expansion, leading to reduced lifespan and stability due to cracking during charging and discharging.

Innovation Solution

Incorporating lithium metal oxide with nickel in the form of single particles as the positive electrode active material and a silicon-based active material with a carbon-based material in the negative electrode, with specific weight percentages to minimize gas occurrence and enhance structural stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a positive electrode active material with high nickel content is used to achieve high energy density, then the energy density is improved, but gas emission increases and lifespan decreases due to cracking during charging and discharging

Engineering Contradiction:

Improveenergy densityVSAvoidlifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses a composite positive electrode active material comprising lithium nickel cobalt manganese oxide (LNMO) combined with lithium metal oxide particles. This composite structure leverages the high energy density of LNMO while the lithium metal oxide component suppresses gas emission and cracking, thereby improving both energy density and lifespan simultaneously

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the composition parameters of the positive electrode active material, specifically controlling the ratio of lithium nickel cobalt manganese oxide to lithium metal oxide, and adjusting the valence state of nickel. By changing these parameters, the material achieves high energy density while maintaining structural stability and reducing gas emission during cycling

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If a silicon-based negative electrode active material is used to achieve high discharge capacity, then the discharge capacity is improved, but volume expansion occurs causing cracks and reduced lifespan

Engineering Contradiction:

Improvedischarge capacityVSAvoidvolume stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies a thin film coating on the silicon-based negative electrode active material particles. This coating layer acts as a protective shell that accommodates volume expansion during lithium insertion/extraction, preventing cracks while maintaining high discharge capacity. The coating allows volumetric change without structural failure

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent controls the particle size and morphology of the silicon-based active material, and optimizes the thickness and composition of the coating layer. By changing these parameters, the material achieves high discharge capacity while maintaining compositional stability and preventing crack formation during volume expansion

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If high nickel content positive electrode material is used to increase energy density, then energy density is improved, but gas occurrence increases at high temperatures

Engineering Contradiction:

Improveenergy densityVSAvoidgas emission

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful gas-generating property of high nickel content material into a beneficial feature by combining it with lithium metal oxide that has high oxygen stability. The lithium metal oxide component suppresses oxygen release and gas formation, while the high nickel content provides high energy density. The harmful gas emission is thus converted into an opportunity to demonstrate the synergistic effect of the composite material

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4418344A1Lithium secondary battery

Publication Date: 2024.08.21 SK ON CO LTD

AI summary

A lithium secondary battery is disclosed. In some implementations, the lithium secondary battery includes a positive electrode including a positive electrode active material including lithium metal oxide including nickel (Ni) and a negative electrode including a negative electrode active material including a silicon-based active material, wherein the positive electrode active material includes 10 wt% or more of lithium metal oxide in the form of single particles based on a total weight of the positive electrode active material, and the negative electrode active material includes 1 to 15 wt% of the silicon-based active material based on a total weight of the negative electrode active material.