Jelly-Roll Electrode Assembly for Low-Resistance Current Collection
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Solution Overview
Problem
Conventional cylindrical battery cells face issues with high resistance, heat generation, and low current-collection efficiency due to concentrated current flow through strip-shaped electrode tabs, which can lead to ignition and electrolyte injection difficulties when scaled for large-capacity applications.
Innovation Solution
A cutting device is used to form sector-shaped cut surface portions and radially bent forming portions in the uncoated regions of electrode assemblies, increasing the welding cross-sectional area and preventing deformation or tearing, thereby reducing resistance and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is used to cut a through hole in the current collector, then the hole can be formed precisely, but the laser beam may be reflected by the battery slurry coating causing instability
Solution Approach 1:
The method performs preliminary actions by first forming a through hole in the aluminum foil current collector before applying the battery slurry coating. This sequence prevents the slurry from interfering with the laser cutting process, eliminating beam reflection issues while maintaining precise hole positioning.
Solution Approach 2:
The harmful battery slurry coating is extracted or removed from the cutting area before laser processing occurs. By applying slurry only after hole formation, the problematic material is excluded from the laser beam path, ensuring stable cutting while preserving the precision benefits of laser technology.
2Ease of manufacture
If conventional methods are used to form through holes, then the process is simpler, but metal debris may remain affecting battery performance
Solution Approach 1:
The mechanical drilling or punching process is replaced with a laser cutting system. This substitution eliminates metal debris generation while achieving precise through hole formation, directly resolving the contradiction between manufacturing simplicity and hole cleanliness.
3Strength
If the current collector has high strength, then it provides good structural support, but it becomes difficult to form through holes
Solution Approach 1:
The laser cutting process utilizes controllable parameters (power, speed, focus) to effectively reduce the material's resistance to cutting. By adjusting these parameters, the strong aluminum foil current collector can be precisely cut without requiring mechanical force that would compromise structural integrity, resolving the contradiction between strength and ease of hole formation.
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 approach enhances current collection efficiency, reduces the risk of ignition and explosion, and maintains electrolyte injection pathways, while securing electrode assembly volume for increased capacity.
Implementation Method 1
a laser beam is used to cut a through hole in the current collector
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4
AI summary
The present invention discloses an electrode assembly, a battery cell, and a battery cell cutting device, and a battery pack and vehicle including the battery cell. The present invention provides an electrode assembly (110) including an electrode cell body portion (111) in which a separator (13) is stacked between a first electrode sheet (11) and a second electrode sheet (12) in the form of a sheet, the first electrode sheet (11), the second electrode sheet (12), and the separator (13) are wound in a jelly-roll type, and an uncoated portion (15), on which an active material layer is not coated, is formed in an end portion of each of the first electrode sheet (11) and the second electrode sheet (12) in a width direction, a plurality of cut surface portions (115) formed by cutting out a portion of the uncoated portion (15) along a circumferential direction around a core portion (112) of the electrode cell body portion (111), and a plurality of forming portions (117) that are disposed between the cut surface portions (115) and formed by pressing and laying down uncut portions (117a) of the uncoated portion (15).