Separator Web Tension Segmentation for Fast Z-Folding Stacks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current battery cell manufacturing processes using Z-folding technology face challenges in maintaining homogeneous web tension, leading to issues such as web tension peaks, separator wrinkling, and mechanical stress, which affect the quality and cycle time of the battery cells.
Innovation Solution
A separator web feeding device with a web tension translation unit that divides the web path into sections with different tensions, combined with a position-controlled web tension control unit to maintain constant web tension, and a separator guide unit for Z-folding, ensuring precise and homogeneous web tension distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the separator guide unit is rigidly coupled to the electrode stacking movers, then the system structure is simplified, but web tension homogeneity deteriorates and cycle time increases
Solution Approach 1:
The web path is divided into multiple sections with different tension characteristics. The first section (from web supply to web tension translation unit) maintains higher tension for stable feeding, while the second section (from web tension translation unit to separator guide unit) maintains lower tension to reduce peaks. This segmentation resolves the contradiction by allowing structure simplification without sacrificing tension homogeneity.
Solution Approach 2:
Different sections of the web path are assigned different tension qualities. The upstream section requires higher tension for controlled feeding, while the downstream section requires lower tension to avoid peaks during Z-folding. The web tension translation unit creates this local quality differentiation, enabling both structural simplicity and tension homogeneity.
2Reliability
If high web tension is applied to prevent separator wrinkling, then separator stability improves, but mechanical stress on electrodes increases
Solution Approach 1:
The web tension parameter is dynamically changed along the web path. The web tension translation unit reduces the tension parameter from the first section to the second section, maintaining enough tension to prevent wrinkling while reducing it to safe levels before the separator contacts the electrodes, thus eliminating mechanical stress damage.
3Productivity
If fast Z-folding cycle is implemented, then productivity increases, but web tension control precision deteriorates
Solution Approach 1:
The web tension translation unit performs preliminary action by adjusting and optimizing the web tension distribution before the separator enters the Z-folding process. This pre-optimization ensures that during fast cycling, the web tension remains homogeneous without requiring complex real-time control, thus maintaining precision while achieving high productivity.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
To improve the quality and cycle time of separator feeding into a Z-folding process during battery cell manufacturing, the separator is fed in the following steps: a) feeding a separator web (16) with a first web tension to a web tension transmission unit (20), which divides the separator web path into sections (38, 40) with different web tensions; b) guiding the separator web (16) from the web tension transmission unit (20) with a second web tension to a separator guide unit (24); c) Z-shaped feeding of the separator web (16) by means of a back-and-forth movement of the separator guide unit (24) to stack the battery cell; and d) controlling the second web tension depending on the position of the separator guide unit (24). Furthermore, devices (14), fixtures (10), controls (54), and computer programs for carrying out the feeding process are proposed.