Separator Adhesive Layout for Low-Resistance Battery Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The application of adhesive on the entire surface of the separator in batteries increases internal resistance due to difficulties in electrolyte impregnation and increased spacing between electrodes, leading to higher internal resistance and potential micro-short circuits.
Innovation Solution
A battery design with an adhesive layer on the separator, where the adhesive layer has a smaller weight per area in the region facing the positive electrode active material layer and a larger weight per area in regions protruding outward, improving electrolyte impregnation, reducing internal resistance, and enhancing vibration resistance and construction workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is applied on the entire surface of the separator, then the separator is firmly attached to the positive electrode and workability is improved, but impregnation of the electrode body with electrolyte solution becomes difficult and internal resistance increases
Solution Approach 1:
The adhesive layer is designed with non-uniform thickness: a first thickness in the region facing the positive electrode active material layer and a second thickness in regions protruding outward. The first thickness is smaller than the second thickness, creating local quality variation that allows electrolyte impregnation at the electrode-active material interface while maintaining firm attachment and vibration resistance at the protruding regions.
2Strength
If adhesive layer thickness is increased to improve attachment, then the separator is more firmly fixed, but the distance between positive and negative electrodes increases and internal resistance increases
Solution Approach 1:
The adhesive layer thickness is optimized locally: thinner regions face the positive electrode active material layer to minimize electrode spacing and internal resistance, while thicker protruding regions provide sufficient attachment strength and vibration resistance. This local quality differentiation resolves the contradiction between attachment strength and internal resistance.
Solution Approach 2:
The adhesive layer is segmented into functionally distinct regions: a first region with smaller thickness for electrolyte impregnation and low internal resistance, and a second region with larger thickness for firm attachment and vibration resistance. This segmentation allows each region to optimize its specific function without compromising the other.
3Ease of manufacture
If adhesive is applied uniformly across the separator, then manufacturing is simplified, but electrolyte solution impregnation becomes difficult
Solution Approach 1:
Rather than uniform adhesive application, the invention implements local quality variation in adhesive thickness. The first thickness facing the positive electrode active material layer is smaller to allow electrolyte impregnation, while the second thickness in protruding regions is larger for mechanical stability. This can be achieved through controlled adhesive application processes that deposit varying thicknesses in different regions.
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
This design reduces internal resistance, prevents micro-short circuits, and improves the battery's vibration resistance and construction efficiency by optimizing the adhesive layer's distribution on the separator.
Implementation Method 1
the impregnation of the electrode body (in particular, positive electrode active material layer) with an electrolyte solution can be improved
Data Source
AI summary
A battery disclosed herein includes an electrode body including a positive electrode including a positive electrode active material layer, a negative electrode, and a separator. The separator includes an adhesive layer on a surface that faces the positive electrode. The adhesive layer includes a first formation region provided so as to face the positive electrode active material layer, and a second formation region provided so as to protrude outward, in an up-down direction or a long side direction of the battery, relative to one end part of the positive electrode active material layer. The first formation region has smaller weight per area than the second formation region.