Wound Electrode Assembly with Segmented Coated Separators
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Solution Overview
Problem
Lithium secondary batteries face challenges in processability and initial resistance during preparation, which can affect their performance and longevity, especially when coated polymer separators increase adhesion but also raise resistance.
Innovation Solution
An electrode assembly with a structure wound on a long sheet-type separation film, where the separator and film are coated with materials like PZT and PLZT, facilitating adhesion and maintaining performance while reducing thickness and resistance, allowing for improved processability and equivalent battery lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polymer separator is coated to increase adhesion to electrodes, then adhesion and safety are improved, but initial resistance increases
Solution Approach 1:
The battery structure is divided into multiple unit cells (first, second, and third unit cells) with different electrode configurations. This segmentation allows different regions to serve different functions: some optimized for adhesion through coating, others optimized for lower resistance pathways, thereby resolving the contradiction between adhesion strength and initial resistance.
Solution Approach 2:
Different regions of the battery are given different local properties. The polymer separator is coated in specific areas to enhance adhesion where needed, while uncoated or differently coated regions maintain lower resistance. The unit cells have different electrode configurations (single electrode vs. double electrode) to create local variations in electrical properties.
2Reliability
If coating material is applied to the separator, then adhesion and high-temperature performance are improved, but manufacturing complexity increases
Solution Approach 1:
The battery is divided into multiple unit cells that can be manufactured and assembled separately. This segmentation simplifies the coating process by allowing smaller, more manageable sections to be coated rather than requiring uniform coating of the entire separator, thereby reducing manufacturing complexity while maintaining reliability.
Solution Approach 2:
The polymer separator is pre-coated with coating material before assembly into the battery structure. This preliminary action allows the coating to be applied under controlled conditions in a separate manufacturing step, simplifying the overall process by preparing components beforehand rather than requiring complex in-situ coating during battery assembly.
3Ease of manufacture
If multiple unit cells are stacked on a long sheet-type separation film, then processability is improved, but initial resistance may increase
Solution Approach 1:
The battery structure is divided into multiple unit cells (first, second, and third unit cells) with different electrode configurations. This segmentation allows different regions to serve different functions: some optimized for adhesion through coating, others optimized for lower resistance pathways, thereby resolving the contradiction between adhesion strength and initial resistance.
Solution Approach 2:
Different regions of the battery are given different local properties. The polymer separator is coated in specific areas to enhance adhesion where needed, while uncoated or differently coated regions maintain lower resistance. The unit cells have different electrode configurations (single electrode vs. double electrode) to create local variations in electrical properties.
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
The electrode assembly enhances the preparation process, reduces initial resistance by 3%, and maintains battery performance and longevity comparable to conventional batteries, with a cost-effective and efficient design.
Implementation Method 1
a separator (30) stacked on the unit cell having a stacking structure has a coating material coated on both sides thereof and the long sheet type separation film (40) has a coating material coated on one side
Data Source
Figure 1
AI summary
Provided is an electrode assembly, and more particularly, an electrode assembly having a structure wound in a state, in which a plurality of unit cells having a stacking structure is disposed on a long sheet type separation film, and including the unit cells having two or more types of configurations of electrode materials, wherein a separator stacked on the unit cell having a stacking structure has a coating material coated on both sides thereof and the long sheet type separation film has a coating material coated on one side thereof. According to the present invention, an electrode assembly improving processability of preparation of a battery while reducing initial resistance during the preparation of the battery as well as having battery lifetime equivalent to that of a conventional battery and a lithium secondary battery including the electrode assembly may be provided.