Composite Cathode Material Balancing Energy Density and Battery Safety

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Solution Overview

Problem

Lithium ion batteries face challenges in achieving high energy density while maintaining low costs and improved safety, particularly in electric vehicle applications where materials like layered lithium nickel manganese cobalt oxide (NMC) are costly and pose safety concerns.

Innovation Solution

A mixed active cathode material comprising cobalt-free layered lithium oxide and phospho-olivine particles, such as lithium nickel manganese oxide and lithium iron phosphate, which reduces costs and enhances safety without compromising energy density, allowing for environmentally friendly production and improved thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high nickel content NMC materials (e.g., NMC622, NMC811) are used to increase energy density, then energy density is improved, but costs increase and safety deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses a composite cathode material consisting of layered lithium nickel manganese oxide (LNMO) particles combined with phospho-olivine particles (such as lithium iron phosphate or lithium iron manganese phosphate). This composite structure allows the material to achieve high energy density from the LNMO component while the phospho-olivine component provides enhanced safety and thermal stability, thereby resolving the contradiction between energy density and safety.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If high nickel content NMC materials (e.g., NMC622, NMC811) are used to increase energy density, then energy density is improved, but costs increase

Engineering Contradiction:

Improveenergy densityVSAvoidcosts

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent replaces expensive cobalt-containing materials with cobalt-free layered lithium nickel manganese oxide combined with phospho-olivine. This substitution uses cheaper materials (manganese and iron-based compounds) to achieve comparable or superior performance, thereby reducing manufacturing costs while maintaining high energy density.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If cobalt-free layered lithium oxide with high manganese content is used, then costs are reduced, but energy density may be impaired

Engineering Contradiction:

ImprovecostsVSAvoidenergy density

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent merges cobalt-free layered lithium nickel manganese oxide (which reduces costs) with phospho-olivine particles (which contribute to energy density). This combination allows the cathode material to achieve cost-effectiveness through cobalt elimination while maintaining or enhancing energy density through the synergistic contribution of both material components.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20230402583A1Cathode Active Material, and Lithium Ion Battery Comprising Said Cathode Active Material

Publication Date: 2023.12.14 BAYERISCHE MOTOREN WERKE AG

AI summary

A cathode active material for a lithium ion battery includes a multitude of first particles that contain a cobalt-free lithium layered oxide, and a multitude of second particles that contain a phospho-olivine. A lithium ion battery includes a cathode containing the cathode active material.