Composite Positive Electrode Material for Battery Output
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries using a positive electrode active material with a small amount of cobalt face challenges in achieving sufficient output performance due to the increasing cost of cobalt and the resulting degradation in battery performance.
Innovation Solution
A positive electrode active material comprising a combination of a first material with 15% or more cobalt and a second material with 5% or less cobalt, where the average secondary particle diameter of the first material is smaller than that of the second material, enhancing the output performance by facilitating lithium ion diffusion and reaction progression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cobalt content in positive electrode active material is reduced to lower cost, then material cost decreases, but output performance deteriorates
Solution Approach 1:
The positive electrode active material is segmented into two distinct components: a first positive electrode active material containing 15% or more cobalt (for high output performance) and a second positive electrode active material containing 5% or less cobalt (for low cost). This segmentation allows each component to fulfill different functional requirements, resolving the contradiction between cost reduction and performance maintenance.
Solution Approach 2:
Different regions of the positive electrode active material have different cobalt concentrations optimized for different purposes. The first material with higher cobalt content is strategically positioned to provide high output performance where needed, while the second material with lower cobalt content reduces overall cost. The average secondary particle diameter relationship (r1 < r2) further optimizes local quality distribution.
2Ease of manufacture
If cobalt content is reduced to address cost concerns, then manufacturing cost decreases, but battery performance becomes insufficient
Solution Approach 1:
The invention creates a composite positive electrode active material system combining two materials with different cobalt contents. The first material (≥15% Co) ensures sufficient output performance and reliability, while the second material (≤5% Co) reduces manufacturing cost. The composite structure allows the system to achieve both cost-effectiveness and performance reliability simultaneously.
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 proposed solution significantly improves the output performance of nonaqueous electrolyte secondary batteries by ensuring efficient lithium ion diffusion and reaction progression, even with a reduced cobalt content, thereby addressing the degradation issues and cost concerns associated with high cobalt usage.
Implementation Method 1
An average secondary particle diameter r1 of the first positive electrode active material is smaller than an average secondary particle diameter r2 of the second positive electrode active material
Data Source
AI summary
A positive electrode active material capable of improving an output performance of a nonaqueous electrolyte secondary battery is provided. A positive electrode active material of a nonaqueous electrolyte secondary battery 1 contains a first positive electrode active material and a second positive electrode active material. In the first positive electrode active material, the content of cobalt is 15% or more on an atomic percent basis in transition metals. In the second positive electrode active material, the content of cobalt is 5% or less on an atomic percent basis in transition metals. An average secondary particle diameter r1 of the first positive electrode active material is smaller than an average secondary particle diameter r2 of the second positive electrode active material.