Graphite Negative Electrode Blend for Fast-Charging Battery Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional negative electrode active materials, such as natural and artificial graphite, suffer from irreversible reactions, low discharge capacity, and degradation in rapid charging performance and lifetime characteristics.
Innovation Solution
A negative electrode comprising a specific blend of uncoated artificial graphite particles with a weight ratio of 4:6 to 6:4, where first particles are 5-7 μm single particles and second particles are 20-25 μm secondary particles formed by agglomerating primary particles, allowing for improved roll-pressing and reduced physical damage, enhancing energy density and charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional natural graphite is used as negative electrode active material, then cost-effectiveness is improved, but irreversible reaction occurs due to irregular structure
Solution Approach 1:
The invention changes the particle morphology parameter from irregular (natural graphite) to spherical (artificial graphite), which eliminates the irreversible reaction problem while maintaining cost-effectiveness
Solution Approach 2:
The invention uses artificial graphite particles that are cost-effective and can be mass-produced, replacing expensive natural graphite while avoiding the irreversible reaction issue
2Productivity
If conventional artificial graphite is used as negative electrode active material, then initial charge/discharge efficiency is improved, but discharge capacity is reduced
Solution Approach 1:
The invention creates a composite particle structure where multiple primary particles are aggregated into secondary particles with spherical morphology, combining the advantages of high initial efficiency and high discharge capacity
3Stability of the object's composition
If amorphous carbon coating layer is formed on graphite particles, then structural stability is improved, but rapid charging performance and lifetime characteristics are degraded
Solution Approach 1:
The invention removes the amorphous carbon coating layer entirely, using only uncoated artificial graphite particles with spherical morphology, which eliminates the degradation of rapid charging performance and lifetime characteristics while maintaining structural stability through the spherical particle structure itself
4Quantity of substance
If electrode thickness is reduced to achieve thinner battery, then energy density is improved, but mechanical strength is reduced
Solution Approach 1:
The invention changes the particle morphology to spherical shape, which improves pack density and allows for thinner electrodes with sufficient mechanical strength, thereby increasing energy density
Data Source
AI summary
A negative electrode whose rapid charging performance and lifetime characteristics are excellent and a secondary battery including the negative electrode. The negative electrode includes a current collector and a negative electrode active material layer on the current collector. The negative electrode active material layer includes a negative electrode active material, and the negative electrode active material includes first uncoated artificial graphite particles and second uncoated artificial graphite particles in a weight ratio of 4:6 to 6:4. The first uncoated artificial graphite particles are single particles having an average particle diameter (D50) of 5 μm to 7 μm, and the second uncoated artificial graphite particles are secondary particles formed by agglomerating a plurality of primary particles. The second uncoated artificial graphite particles have an average particle diameter (D50) of 20 μm to 25 μm.