Negative Electrode Orientation Control in Lithium Battery

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Solution Overview

Problem

The electrical characteristics of rechargeable lithium batteries can degrade due to misorientation of negative active material particles during the rolling process, affecting the performance of the battery.

Innovation Solution

A spirally-wound electrode assembly with a negative electrode featuring alternating orientation and non-orientation portions, where the orientation portions are oriented at a constant angle and have a higher degree of divergence, while the non-orientation portions have a lower degree of divergence, are alternately arranged to prevent misorientation during the rolling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rolling process is performed after coating the negative active material to orient particles, then the negative active material particles are oriented in a constant direction with respect to the base member surface, but the rolling process may cause the negative active material to be misoriented, thereby degrading performance of the battery

Engineering Contradiction:

Improveorientation precision of negative active material particlesVSAvoidbattery performance stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The electrode assembly is divided into multiple electrode pairs stacked in sequence, with each pair consisting of a negative electrode, positive electrode, and separator. This segmentation allows independent optimization of each electrode pair's active material orientation without affecting the entire battery structure, preventing misorientation propagation while maintaining constant direction orientation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different orientation characteristics to different regions of the negative active material particles. Specifically, particles in different electrode pairs can have different orientation angles relative to the base member surface, allowing local optimization of ion transport pathways while maintaining overall structural integrity and preventing misorientation degradation.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the negative active material particles are oriented in a constant direction with respect to the base member surface, then the orientation may be carried out after coating, but the rolling process may cause misorientation

Engineering Contradiction:

Improveorientation process simplicityVSAvoidparticle orientation consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent performs preliminary orientation of negative active material particles during the coating process itself, before the rolling process occurs. By establishing the constant direction orientation in advance during coating, the subsequent rolling process cannot cause misorientation, as the particles are already fixed in their optimal orientation relative to the base member surface.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11152606B2Electrode assembly and rechargeable battery including the same

Publication Date: 2021.10.19 SAMSUNG SDI CO LTD

AI summary

An electrode assembly including a separator between a positive electrode and a negative electrode. Each of the positive electrode and the negative electrode includes a base member and an active material layer at at least one side of the base member. The active material layer of the negative electrode includes an alternating arrangement of orientation portions and non-orientation portions. Each of the orientation portions is oriented to have a constant angle with respect to one side of the negative electrode.