Carbon-Coated Graphite Anode Porosity for High-Power Li-Ion Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium-ion secondary batteries face challenges in achieving high power performance, particularly in applications requiring fast charging and discharging, which is crucial for electric vehicles like PHEVs and HEVs.
Innovation Solution
The negative electrode is optimized by controlling the porosity, specific surface area, amorphous carbon coating amount, graphitization degree, and particle size of the amorphous carbon-coated graphite active material within specific ranges to enhance lithium ion transmission and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the particle size of active material is reduced to improve power performance, then lithium ion transmission is enhanced, but manufacturing precision and material cost control become more difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of graphite active material within specific ranges (D10≥3μm, D50≥6μm, D90≥9μm) and adjusting porosity (35-45%), specific surface area (0.8-1.5 m²/g), and carbon coating amount (0.5-3.0%) to optimize power performance while maintaining manufacturability
Solution Approach 2:
The patent uses composite materials by coating graphite particles with amorphous carbon to create amorphous carbon-coated graphite composite material, which improves conductivity and lithium ion transmission while maintaining structural integrity and controlling particle size distribution
2Power
If surface coating is applied to improve power performance, then lithium ion transmission is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent applies porous materials by creating a porous structure on the negative electrode surface with controlled porosity (35-45%) and specific surface area (0.8-1.5 m²/g), which enhances lithium ion transmission pathways while maintaining a relatively simple manufacturing process through slurry coating and drying
Solution Approach 2:
The patent changes physical parameters by controlling the carbon coating amount (0.5-3.0% by weight) and specific surface area to optimize the balance between power performance and manufacturing simplicity
3Power
If porosity is increased to enhance lithium ion transmission, then power performance is improved, but electrode structural strength decreases
Solution Approach 1:
The patent optimizes porosity within a specific range (35-45%) to balance lithium ion transmission and structural strength, avoiding excessive porosity that would compromise mechanical integrity while ensuring sufficient ion pathways
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
This optimization significantly improves the power performance of lithium-ion secondary batteries by enhancing lithium ion transmission and reducing charge transfer impedance, leading to better power characteristics.
Implementation Method 1
ensuring the lithium ion transmission of the inner coating
Data Source
AI summary
A negative electrode for a lithium-ion secondary battery and a manufacturing method therefor. The negative electrode for a lithium-ion secondary battery comprises: a negative electrode current collector and a negative electrode active material layer formed on the surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material; the negative electrode active material comprises amorphous carbon-coated graphite; the porosity P of the negative electrode is 34.0%-55.0%; the specific surface area S of the negative electrode active material is from 0.80 m2/g to 3.20 m2/g; the amorphous carbon coating amount C of the negative electrode active material is 0.80%-3.35%; the graphitization degree G of the negative electrode active material is 83.0%-95.0%; and the particle size D of the negative electrode active material is 3.0-14.0 µm. Also provided are a lithium-ion secondary battery comprising the negative electrode and an electric device. The material level and the electrode sheet level of a negative electrode end are reasonably matched, thereby remarkably improving the power performance of the lithium-ion secondary battery.