Adhesive Separator Folding for Stable Electrode Alignment
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Solution Overview
Problem
Conventional Z-folding type electrode assemblies in battery cells face issues with electrodes displacing from their fixed positions due to lack of adequate adhesion and alignment, leading to reduced heat transfer and adhesive strength, especially when using separator sheets with low adhesive strength.
Innovation Solution
An apparatus and method for manufacturing electrode assemblies that include a separator supply unit, tensioners, and adhesive application to ensure precise folding and adhesion of electrodes and separator sheets in a zigzag configuration, using nozzles and pressure rollers to maintain electrode position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a separate stacking alignment process is performed after stacking electrodes and separator sheet, then electrode alignment is improved, but overall thickness of stacked body increases and adhesive strength is lowered
Solution Approach 1:
The separator sheet is prepared with adhesive layers and folded into the final zigzag configuration before the electrodes are attached. This preliminary folding and adhesive application ensures that when electrodes are stacked, they automatically achieve precise alignment without requiring subsequent thickness-increasing alignment processes
Solution Approach 2:
The adhesive strength is enhanced by controlling the adhesive layer thickness within a specific range (1-10 μm) and by selecting adhesive materials with appropriate glass transition temperatures. This parameter optimization ensures strong adhesion without requiring additional alignment processes that would increase overall thickness
2Ease of manufacture
If separator sheet with low adhesive strength is used, then manufacturing cost is reduced, but electrodes become displaced from fixed positions
Solution Approach 1:
Adhesive layers are applied locally at specific positions on the separator sheet where electrodes need to be fixed, rather than coating the entire separator sheet. This localized adhesive application maintains reliability at critical positions while reducing overall material usage and cost
Solution Approach 2:
The separator sheet is constructed as a composite structure combining the base separator material with adhesive layers having specific properties (controlled thickness, glass transition temperature, and composition). This composite approach achieves reliable electrode positioning without requiring expensive high-adhesive-strength separator materials throughout
3Manufacturing precision
If overall thickness of stacked body is increased for alignment, then electrode alignment is improved, but heat transfer to interior is insufficient
Solution Approach 1:
The separator sheet is pre-folded into the zigzag configuration with built-in alignment features before electrode stacking. This preliminary preparation ensures precise electrode alignment is achieved through the folding geometry itself, eliminating the need to increase overall thickness for alignment purposes
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
Prevents electrode displacement, enhances adhesion, and maintains alignment, improving heat transfer and adhesive strength, thereby enhancing the performance and efficiency of battery cells.
Implementation Method 1
an adhesive layer formed between each of the electrodes and the separator sheet
Data Source
AI summary
An apparatus for manufacturing an electrode assembly includes a separator supply unit, table, separator guide, first adhesive supply unit, and pair of tensioners. The separator supply unit is configured for supplying a separator sheet from which a separator is formed. The table is configured for supporting electrodes and sections of the separator sheet. The separator guide is configured for guiding the separator sheet to fold in a particular folding direction. The first adhesive supply unit is configured for applying an adhesive to portions of the separator sheet and the electrodes supported by the table. The pair of tensioners are each configured for pressing an uppermost section of the separator sheet guided by the separator guide against the table or against a placed electrode that directly underlies the uppermost section. The electrode assembly is manufactured by a process using the apparatus.