Lithium Battery Anode Graphite Mixture Expansion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in achieving improved power output and life-span due to high electrode expansion rates and resistance issues, particularly when using natural graphite as an anode active material, and introducing artificial graphite does not adequately address these problems.
Innovation Solution
A lithium secondary battery design incorporating a mixture of artificial and natural graphite with specific sphericity and particle size distribution characteristics, along with a controlled mixing weight ratio, to enhance electrode density and suppress expansion, thereby improving power output and life-span.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural graphite is used as anode active material, then battery capacity is improved, but electrode expansion rate increases causing poor life-span
Solution Approach 1:
The patent uses a composite anode active material consisting of natural graphite particles (with sphericity ≥0.96) combined with other graphite materials or carbon materials. This composite structure leverages the high capacity of natural graphite while the spherical morphology and composite nature reduce expansion stress and improve structural stability, thereby extending battery life-span.
Solution Approach 2:
The patent changes the physical parameters of natural graphite by controlling its sphericity to be 0.96 or higher and adjusting particle size distribution (D50 between 8-15 μm). These parameter changes reduce electrode expansion rate and improve packing density, resolving the contradiction between capacity and life-span.
2Reliability
If artificial graphite is introduced to overcome poor life-span, then life-span is improved, but power output is not improved and resistance increases
Solution Approach 1:
The patent optimizes particle size parameters (D50: 8-15 μm, D90/D10 ratio: 1.5-3.0) and sphericity (≥0.96) of natural graphite to achieve a balance between life-span and power output. The controlled particle size distribution improves both structural stability for long life and surface area for good power output, avoiding the resistance issues of artificial graphite.
3Quantity of substance
If high density active material mixture is employed to implement high capacity battery, then battery capacity is improved, but life-span is degraded
Solution Approach 1:
The patent optimizes the density and particle size distribution parameters of the active material mixture, using spherical natural graphite with controlled D50 (8-15 μm) and narrow size distribution (D90/D10: 1.5-3.0). This creates a high-density packing structure that maintains high capacity while reducing internal stress and improving cycle stability for extended life-span.
Data Source
AI summary
A lithium secondary battery includes a cathode, an anode and a non-aqueous electrolyte. The anode includes an anode active material which contains a mixture of an artificial graphite and a natural graphite. A sphericity of the natural graphite is 0.96 or more. The lithium secondary battery including the anode has improved life-span and power properties.