Positive Electrode Particle Composition for High-Temperature Battery Life
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high energy density, capacity, and lifespan, especially at elevated temperatures, due to issues with electrochemical reaction resistance and outgassing.
Innovation Solution
A positive electrode material comprising a specific combination of secondary particles with varying sizes and nickel content, including a first secondary particle (13 μm to 20 μm), a second secondary particle (7 μm to 13 μm), and a one-body particle (1 μm to 7 μm), optimized to enhance lithium diffusion and reduce degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a nickel-based active material with high nickel content is used to increase capacity, then the energy density improves, but the electrochemical reaction resistance increases and lifespan decreases at high temperatures
Solution Approach 1:
The positive electrode active material is divided into three distinct particle size groups (first secondary particles: 13-20 μm, second secondary particles: 7-13 μm, one-body particles: 1-7 μm), each with optimized nickel content. This segmentation allows different particle sizes to fulfill different functions: larger particles provide capacity while smaller particles ensure adequate reaction kinetics and high-temperature stability.
2Productivity
If the particle size is reduced to increase surface area and improve reaction kinetics, then the electrochemical reaction efficiency improves, but the outgassing increases
Solution Approach 1:
Different nickel content ratios are assigned to different particle size ranges. The first secondary particles (13-20 μm) have a nickel content of 85-97 mol%, the second secondary particles (7-13 μm) have 80-90 mol%, and the one-body particles (1-7 μm) have 90-99 mol%. This local quality differentiation optimizes both reaction efficiency and outgassing suppression for each particle size category.
3Ease of manufacture
If a single particle size distribution is used to simplify manufacturing, then the manufacturing process is simplified, but the homogeneity of electrochemical reaction deteriorates
Solution Approach 1:
The invention specifies precise particle size ranges and nickel content ratios for three different particle groups to optimize electrochemical performance. First secondary particles: 13-20 μm with 85-97 mol% Ni, second secondary particles: 7-13 μm with 80-90 mol% Ni, one-body particles: 1-7 μm with 90-99 mol% Ni. These parameter specifications ensure homogeneous electrochemical reactions while maintaining manufacturability through clear classification criteria.
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 positive electrode material improves the capacity and lifespan of lithium secondary batteries at high temperatures, while also reducing electrochemical reaction resistance and outgassing.
Implementation Method 1
both of which contain active materials that allow for intercalation and deintercalation of lithium ions
Implementation Method 2
The lithium battery produces electricity through oxidation and reduction reactions upon intercalation/deintercalation of the lithium ions
Implementation Method 3
The lithium battery produces electricity through oxidation and reduction reactions upon intercalation/deintercalation of the lithium ions
Data Source
AI summary
A positive electrode material for lithium secondary batteries and a lithium secondary battery including the same are disclosed. The positive electrode material includes: i) a first secondary particle having a size in a range of 13 μm to 20 μm and containing an agglomerate of primary particles having a size in a range of 1 μm or less; ii) a second secondary particle having a size in a range of 7 μm to 13 μm and containing an agglomerate of primary particles having a size in a range of 1 μm or less; and iii) a one-body particle having a size in a range of 1 μm to 7 μm and containing primary particles, wherein a nickel content of each of the particles satisfies Relation 1:nickel content of the one-body particle>nickel content of the first secondary particle>nickel content of the second secondary particle.