Battery Electrode Sheet With Oblique Slots for Stronger Tab Welding
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Solution Overview
Problem
Existing battery electrode sheets face challenges such as low weld strength, sparse weld residue, and increased battery internal resistance due to the flattening process, which also affects electrolyte liquid injection speed and injection effect.
Innovation Solution
A battery electrode sheet with a coated zone and a bare foil zone featuring multiple oblique slots and protrusions in an alternating manner, designed to reduce resistance during flattening and enhance weld strength and electrolyte injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bare foil zone is flattened to form a tab end face, then the battery structure is formed, but the weld strength is low and weld residue is sparse due to small contact area
Solution Approach 1:
The bare foil zone is divided into multiple segments by cutting oblique slots, creating a stepped structure with multiple levels. This segmentation increases the total contact area between the tab end face and collector plate, thereby improving weld strength and weld residue formation.
Solution Approach 2:
The invention transitions from a flat two-dimensional tab end face to a three-dimensional stepped structure by cutting oblique slots at specific angles. This dimensional change creates multiple contact levels, significantly increasing the contact area with the collector plate without increasing the overall footprint.
2Productivity
If the tab end faces are flattened close together, then the battery structure is compact, but the electrolyte liquid injection speed and injection effect are affected
Solution Approach 1:
The oblique slots divide the tab end face into multiple stepped levels, creating channels and pathways that facilitate electrolyte liquid flow. This segmentation allows electrolyte to reach deeper into the electrode structure, improving injection speed and distribution even when tabs are arranged closely.
Solution Approach 2:
The stepped structure created by oblique slots effectively creates a porous-like configuration that enhances fluid penetration. The multiple levels and channels formed by the slots allow electrolyte liquid to flow more efficiently through the tab end face, improving injection effect.
3Shape
If the bare foil zone is cut perpendicular to the longitudinal direction and bent to achieve compaction, then the structure is compacted, but a level flat surface is difficult to achieve
Solution Approach 1:
Instead of cutting perpendicular to the longitudinal direction, the invention uses oblique slots cut at specific angles (e.g., 45 degrees) relative to the longitudinal direction. This asymmetric cutting approach, combined with the flattening process, naturally produces a level flat surface by distributing the material deformation more uniformly.
Solution Approach 2:
The invention changes the cutting angle parameter from perpendicular (90 degrees) to oblique (e.g., 45 degrees), which fundamentally alters the flattening behavior. This parameter change allows the material to deform more uniformly during flattening, achieving a level flat surface more easily.
4Strength
If the flattening wheel presses the bare foil zone, then the tab end face is formed, but resistance is high causing breaking and shedding of small particles
Solution Approach 1:
The oblique slots pre-segment the bare foil zone into smaller sections, which reduces the overall resistance during flattening. Each segment can be pressed independently, distributing the flattening force and reducing the likelihood of particle breaking and shedding.
Solution Approach 2:
The oblique slots create local variations in the material structure, with different regions having different properties. The areas between slots are more robust and can withstand flattening pressure better, while the slots themselves provide stress relief, reducing particle breaking.
Data Source
AI summary
A battery electrode sheet, a cylindrical battery, and a method for manufacturing same. The battery electrode sheet comprises a coated zone coated with an electrode material, and a bare foil zone, the bare foil zone being provided with multiple oblique slots and multiple oblique protrusions in an alternating manner. The cylindrical battery comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet and/or the negative electrode sheet being the battery electrode sheet. The method for manufacturing a cylindrical battery comprises flattening positive/negative electrode end faces of a cell, wherein the direction of flattening is the same as the direction of inclination of oblique protrusions.