Multi-Layered Anode Structure for Lithium Secondary Battery

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Solution Overview

Problem

Lithium secondary batteries face challenges in ion mobility and cycle life due to decreased surface porosity during the press process, which hinders electrolyte penetration and ion transfer, leading to degraded battery performance.

Innovation Solution

An anode with a multi-layered active material layer, comprising a first anode active material with higher press density and smaller particle diameter, and a second anode active material with lower press density and larger particle diameter, is used to improve surface porosity and ion mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single anode active material slurry is coated and pressed to obtain uniform thickness, then manufacturing precision is improved, but surface porosity decreases leading to degraded ion mobility

Engineering Contradiction:

Improveuniform thicknessVSAvoidion mobility

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The single-layer anode structure is segmented into multiple layers with different active materials having different press densities. This segmentation allows each layer to contribute differently to the overall structure, maintaining uniform thickness while preserving surface porosity for ion mobility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the anode (different layers) are given different local qualities through the use of active materials with different press densities. The lower press density material maintains higher porosity for ion transport, while the overall structure achieves uniform thickness through the composite layering approach.

Inventive Principle:

Principle #3Local quality

2Strength

If press density is increased to improve structural integrity, then strength is improved, but surface porosity decreases hindering electrolyte penetration

Engineering Contradiction:

Improvestructural integrityVSAvoidelectrolyte penetration

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The anode is segmented into layers with different press densities, allowing the lower press density layer to maintain surface porosity for electrolyte penetration while the overall multi-layer structure provides structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The anode uses a composite structure of different active materials with different press densities. This composite approach allows the combination of materials with complementary properties, achieving both structural integrity and sufficient porosity for electrolyte penetration.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10263242B2Anode for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2019.04.16 LG ENERGY SOLUTION LTD

AI summary

Provided is an anode for a lithium secondary battery composed of a multi-layered structure including an electrode current collector, a first anode active material layer including a first anode active material formed on the electrode current collector, and a second anode active material layer including a second anode active material having relatively lower press density and relatively larger average particle diameter than the first anode active material.Since an anode according to an embodiment of the present invention may include a multi-layered active material layer including two kinds of anode active materials having different press densities and average particle diameters on an electrode current collector, porosity of the surface of the electrode may be improved even after a press process to improve ion mobility into the electrode. Thus, charge characteristics and cycle life of a lithium secondary battery may be improved.