Anode Core-Shell Coating for Battery Stability

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Solution Overview

Problem

Lithium secondary batteries face challenges in maintaining stability and performance due to side reactions and mechanical damage from repeated charging and discharging, which degrade the anode active material's conductivity and capacity.

Innovation Solution

An anode for secondary batteries is developed using first anode active material particles with a core and a carbon-based coating layer, and second anode active material particles with a carbon-based material assembly, optimizing particle size and composition to enhance hardness, electrolyte resistance, and high-temperature storage properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the anode active material composition and structure are changed to improve stability, then the stability is improved, but the conductivity is degraded and power is deteriorated

Engineering Contradiction:

Improvestability of anode active material particlesVSAvoidconductivity and power of secondary battery

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the core particle maintains high stability (using graphite-based or amorphous carbon-based materials) while the coating layer on the surface provides high conductivity. This local differentiation of material properties resolves the contradiction by having different regions serve different functions: the core ensures stability during repeated charging/discharging, while the conductive coating layer maintains electrical conductivity and power performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining core particles with coating layers formed from pitch particles. The composite structure integrates the stability benefits of graphite/amorphous carbon core materials with the conductivity advantages of the pitch-based coating, thereby simultaneously achieving both stability improvement and conductivity maintenance that resolves the technical contradiction.

Inventive Principle:

Principle #40Composite materials

2Strength

If a coating layer is formed on core particles to improve hardness and stability, then mechanical damage resistance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvehardness of anode active material particlesVSAvoidcomplexity of anode structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming core particles with specific properties (graphite-based or amorphous carbon-based materials with appropriate hardness) before applying the coating layer. This preliminary preparation of core particles with suitable mechanical properties simplifies the overall manufacturing process while still achieving the desired hardness improvement, as the core particles are already optimized for mechanical strength before the coating step.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses parameter changes by carefully controlling the particle diameter of pitch particles (average 1.5-3 μm, maximum 20 μm or less) and the coating layer content (0.5-3 parts by weight per 100 parts core particle). By optimizing these parameters, the coating process becomes more efficient and less complex, while still achieving the desired hardness improvement and structural integrity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If pitch particles with specific size range are used to form coating layer, then conductivity and pressing properties are improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveconductivity and pressing properties of anodeVSAvoidprecision of pitch particle size control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by defining a specific range for pitch particle diameter (average 1.5-3 μm, maximum 20 μm or less) and coating layer content (0.5-3 parts by weight per 100 parts core particle). By optimizing these parameters, the patent achieves improved conductivity and pressing properties while setting realistic manufacturing precision requirements that balance performance with manufacturability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20230063421A1Anode for secondary battery and secondary battery including the same

Publication Date: 2023.03.02 SK ON CO LTD

AI summary

Secondary batteries including the anode and having improved capacity properties and stability are disclosed. In an aspect, an anode for a secondary battery includes first anode active material particles, each of the first anode active material particles having a single particle structure that includes a core particle and a coating layer formed on a surface of the core particle, and second anode active material particles including a carbon-based material, wherein each of the second anode active material particles includes an assembly of a plurality of sub-particles.