Positive Electrode Composition for Dense Packing and Battery Life
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Solution Overview
Problem
Existing batteries face challenges in achieving high energy density and long service life, particularly due to inefficiencies in the stacking and compacting of positive electrode active materials.
Innovation Solution
A positive electrode active material composition comprising two types of materials with different crystal forms and controlled particle size distributions, allowing for dense stacking and improved compacted density, along with specific doping and cladding layers to enhance conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single type of positive electrode active material is used, then the manufacturing process is simple, but the stacking density and energy density are limited
Solution Approach 1:
The patent uses a composite material system consisting of two distinct positive electrode active materials: a phosphate-based material (e.g., LiFePO4) and an oxide-based material (e.g., LiCoO3, LiMn2O4, or LiNi0.8Co0.1Mn0.1O2). These materials have different crystal structures, particle size distributions, and electrochemical properties. By combining them in a composite positive electrode, the patent achieves higher stacking density and improved energy density while maintaining manageable manufacturing complexity through established battery production techniques.
2Speed
If particle size is reduced to improve reaction kinetics, then charge/discharge rate improves, but stacking density decreases
Solution Approach 1:
The patent applies local quality by assigning different particle size characteristics to different materials in the composite. The phosphate-based material uses finer particles (Dv10: 0.5-5 μm, Dv50: 5-15 μm) to enhance reaction kinetics and charge/discharge rates. The oxide-based material uses coarser particles (Dv10: 5-15 μm, Dv50: 15-30 μm) to maximize stacking density. This spatial differentiation of particle sizes within the composite electrode allows simultaneous optimization of both electrochemical performance and packing efficiency.
Solution Approach 2:
The patent changes the particle size distribution parameters differently for each material component. By controlling the Dv10 and Dv50 values within specific ranges for each material type, the patent optimizes the balance between surface area (for reaction kinetics) and packing efficiency (for stacking density). The phosphate material's finer size distribution compensates for the oxide material's coarser size, achieving overall system optimization.
3Quantity of substance
If compacted density is increased to improve energy density, then volume energy capacity improves, but manufacturing difficulty increases
Solution Approach 1:
The patent optimizes the particle size distribution parameters (Dv10 and Dv50) of both materials to achieve improved compacted density within the range of 2.8-3.5 g/cm³. This parameter optimization allows the composite positive electrode to reach high compacted density without excessive manufacturing difficulty, as the particle sizes are controlled within practical ranges that facilitate conventional electrode fabrication processes while achieving the desired density improvement for higher volume energy capacity.
4Ease of manufacture
If phosphate material with low cost is used, then manufacturing cost decreases, but compacted density is insufficient
Solution Approach 1:
The patent creates a composite material system that combines cost-effective phosphate-based materials (such as LiFePO4, which uses abundant iron and phosphorus) with oxide-based materials. The phosphate component provides low manufacturing cost and good thermal stability, while the oxide component contributes higher compacted density. This composite approach allows the positive electrode to achieve both economic advantages and improved compacted density, with the overall compacted density reaching 2.8-3.5 g/cm³ while maintaining cost-effectiveness.
Data Source
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AI summary
The present application provides a positive electrode active material composition, a positive electrode plate, a battery, and an electrical apparatus. The positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material the crystal form of which is different from that of the first positive electrode active material; the first positive electrode active material comprises a phosphate; a particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, the volume distribution peak with the maximal peak intensity is marked as a first peak, a volume distribution particle size corresponding to the maximal peak intensity of the first peak is marked as Dv1, a volume distribution peak with the submaximal peak intensity is marked as a second peak, and a volume distribution particle size corresponding to the maximal peak intensity of the second peak is marked as Dv2, with 0 < |Dv1-Dv2| / Dv1 ≤ 50.