Secondary Battery Electrode Composition for Fast Charging Life
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Solution Overview
Problem
Conventional secondary batteries using lithium cobalt oxide and artificial graphite as positive and negative electrode active materials face issues with rapid degradation, surface instability, and poor high-temperature storage performance due to uncontrolled particle size and non-uniform pores, leading to reduced life characteristics and quick charging performance.
Innovation Solution
A secondary battery design incorporating a positive electrode with Al-doped lithium cobalt oxide having a bimodal particle diameter distribution and surface-coated with Zr, combined with a negative electrode using both non-coated and carbon-coated artificial graphite, to improve adhesion and reduce cell diffusion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional granulation process is used to form secondary particles, then production efficiency is improved, but micropowder separation occurs causing reduced electrode adhesion and poor high-temperature storage performance
Solution Approach 1:
The patent controls the particle size parameters of primary particles within specific ranges (D10: 3-8 μm, D50: 8-15 μm, D90: 15-25 μm) and manages particle size distribution to prevent micropowder separation during granulation, thereby maintaining both production efficiency and electrode adhesion
Solution Approach 2:
The patent creates a composite structure where primary particles of controlled size are granulated into secondary particles with consistent morphology, forming a composite material system that prevents micropowder separation while maintaining production efficiency
2Reliability
If LiCoO2 is used as positive electrode active material, then excellent physical properties and electrochemical characteristics are achieved, but crystal structure instability at voltage ≥4.3V causes rapid degradation of life characteristics
Solution Approach 1:
The patent applies a surface coating layer to the LiCoO2 particles before battery assembly, creating a protective barrier that prevents harmful reactions between the LiCoO2 surface and electrolyte, thereby maintaining crystal structure stability and extending battery life at high voltages
Solution Approach 2:
The patent optimizes the particle size parameters of LiCoO2 (D10: 3-8 μm, D50: 8-15 μm, D90: 15-25 μm) to reduce internal stress and prevent crystal structure collapse during charge-discharge cycles, thereby improving both electrochemical characteristics and life characteristics
3Quantity of substance
If high voltage is applied to develop high-capacity secondary battery, then capacity is improved, but surface instability and structural instability of LiCoO2 are increased
Solution Approach 1:
The patent applies a protective surface coating to LiCoO2 particles before high-voltage operation, preventing surface degradation and structural collapse that would otherwise occur during high-voltage charging, thereby enabling high capacity while maintaining stability
Solution Approach 2:
The patent creates a composite structure with coated LiCoO2 particles that combines the high capacity benefits of LiCoO2 with the stability benefits of the coating material, enabling operation at high voltages without degradation
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 design significantly enhances the life characteristics and quick charging performance of the secondary battery by stabilizing the crystal structure and reducing resistance, resulting in improved durability and capacity retention.
Implementation Method 1
the lithium cobalt oxide includes Al doping and is surface-coated with Zr
Implementation Method 2
the lithium cobalt oxide includes Al doping and is surface-coated with Zr
Implementation Method 3
The negative electrode includes a negative electrode active material capable of intercalation/deintercalation of lithium ions released from the positive electrode
Implementation Method 4
a second negative electrode active material that is an artificial graphite having a carbon coating layer on the surface thereof
Data Source
AI summary
Disclosed is a secondary battery including a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode current collector, and a positive electrode active material layer disposed on the positive electrode current collector, the positive electrode active material layer including a positive electrode active material and a binder. The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, the negative electrode active material layer including a negative electrode active material and a binder. The negative electrode active material includes a first negative electrode active material that is an artificial graphite having no carbon coating layer on the surface thereof and a second negative electrode active material that is an artificial graphite having a carbon coating layer on the surface thereof.