Artificial Graphite Anode Composition for Press Crack Prevention
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Solution Overview
Problem
Lithium secondary batteries face issues with anode material cracking during the press process, leading to insufficient electrode density and power degradation due to particle orientation properties, which affects the stability and capacity retention of the battery.
Innovation Solution
The use of a combination of assembly-type and single-type artificial graphite particles, where the single-type particles are added to improve mechanical stability and fill gaps between assembly-type particles, enhancing electrode density and preventing particle cracks, while maintaining an XRD orientation index within a specific range to improve lithium ion path efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If granulated artificial graphite particles are used to improve capacity, then particle cracks occur during press process leading to insufficient electrode density
Solution Approach 1:
The patent combines granulated artificial graphite particles with single-type artificial graphite particles to form a composite anode active material. The single-type particles fill gaps between granulated particles and provide mechanical support, preventing cracks during pressing while maintaining high capacity from the granulated structure.
2Quantity of substance
If assembly-type artificial graphite particles are used to increase capacity, then power degradation occurs due to particle orientation properties
Solution Approach 1:
The patent creates local quality differences by distributing single-type artificial graphite particles among assembly-type particles. The single-type particles have different orientation characteristics that compensate for the orientation issues of assembly-type particles, locally improving lithium ion transport pathways and reducing power degradation.
3Strength
If single-type artificial graphite particles are added to fill gaps, then mechanical stability improves but particle cracking prevention requires optimized composition
Solution Approach 1:
The patent optimizes the composition ratio between assembly-type and single-type artificial graphite particles, controlling the content of single-type particles within 5-50 wt% of the total anode active material. This parameter optimization ensures sufficient mechanical stability from single-type particles while preventing excessive cracking through proper compositional balance.
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 approach results in improved mechanical stability, capacity retention, and power performance by preventing particle cracking and optimizing electrode density, thus enhancing the overall performance and lifespan of the secondary battery.
Implementation Method 1
single-type particles are added to improve mechanical stability and fill gaps between assembly-type particles, enhancing electrode density
Implementation Method 2
single-type particles are added to improve mechanical stability and fill gaps between assembly-type particles, enhancing electrode density and preventing particle cracks
Implementation Method 3
An X-ray diffraction (XRD) orientation index defined as a ratio of x-ray diffraction peak intensities of a (004) plane and a (110) plane and represented as I(004)/I(110) by an XRD analysis measured from the anode active material layer
Data Source
Figure 1~2
Figure 3
AI summary
An anode for a lithium secondary battery includes an anode current collector, and an anode active material layer on the anode current collector. The anode active material layer includes an anode active material that includes assembly-type artificial graphite particles and single-type artificial graphite particles. An XRD orientation index defined as a ratio of peak intensities of a (004) plane and a (110) plane and represented as I(004)/I(110) by an XRD analysis measured from the anode active material layer is in a range from 6 to 13.