Electrode Tab Cutting Geometry to Minimize Burr Damage in Batteries
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Solution Overview
Problem
Existing secondary battery manufacturing processes result in electrode damage due to burrs formed during the cutting of electrode tabs, leading to pinholes or cracks in the electrodes.
Innovation Solution
An apparatus and method that utilize a cutter with an inclined surface and a fixing die to minimize burr formation by cutting the electrode tab in a direction away from the electrode, and attaching the tab in a way that burrs protrude towards the battery case, thereby reducing stress on the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the diaphragm to prevent dendrite formation and improve safety, then battery safety and reliability are improved, but internal stress accumulates during winding/d unwinding cycles causing coating flaking and performance degradation
Solution Approach 1:
The coating layer is divided into multiple layers: a lower adhesive layer (SiOx) that bonds to the diaphragm substrate, and an upper functional layer (Al2O3) that provides dendrite prevention. This segmentation allows each layer to specialize in one function, reducing internal stress and preventing flaking while maintaining safety performance.
Solution Approach 2:
The SiOx layer acts as an intermediary between the diaphragm substrate and the Al2O3 coating layer. It provides adhesion to the substrate while allowing the Al2O3 layer to maintain its protective function, thereby preventing coating flaking caused by internal stress during winding and unwinding cycles.
2Manufacturing precision
If the diaphragm is stretched tightly during assembly to ensure proper fit and function, then assembly precision is improved, but the membrane rupture voltage decreases reducing battery safety
Solution Approach 1:
The diaphragm is pre-stretched by 5-15% during assembly to optimize its mechanical properties. This controlled parameter change ensures proper fit and assembly precision while maintaining the membrane rupture voltage above 2.2V, preventing excessive tension that would reduce safety.
3Reliability
If a thick protective coating is applied to prevent dendrites effectively, then battery safety is improved, but the coating flakes off during winding and unwinding due to accumulated internal stress
Solution Approach 1:
The protective coating is segmented into a thin adhesive SiOx layer (lower layer) and a functional Al2O3 layer (upper layer). This segmentation allows the coating to be thick enough for effective dendrite prevention while the SiOx layer manages internal stress to prevent flaking during manufacturing processes.
Solution Approach 2:
Different regions of the coating have different properties: the SiOx layer provides adhesion and stress management, while the Al2O3 layer provides dendrite protection. This local quality differentiation allows the coating to meet multiple requirements simultaneously without flaking.
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
Reduces electrode damage by minimizing burr protrusion and stress concentration, enhancing the integrity and stability of the secondary battery.
Implementation Method 1
a heating unit, which heats the slurry to a temperature within a specific temperature range
Implementation Method 2
a coating formation unit, which forms a coating layer on the diaphragm using the slurry in a coated state
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The present invention relates to an apparatus for manufacturing secondary battery, a method for manufacturing a secondary battery using the same, and a secondary battery manufactured using the same, and more particularly, to an apparatus for manufacturing a secondary battery, which cuts an electrode tab of the secondary battery, a method for manufacturing a secondary battery using the same, and a secondary battery manufactured using the same. The present invention provides an apparatus for manufacturing a secondary battery, which comprises: an electrode assembly in which electrodes and separators are alternately stacked; and an electrode tab attached to each of the electrodes, the apparatus including: a cutter disposed at one side of the electrode tab to move toward the electrode tab so as to cut a portion to be cut of the electrode tab; and a fixing die provided to cross the cutter at the other side of the electrode tab, wherein the cutter includes: a pressing surface configured to press the electrode tab; and an inclined surface provided at a position corresponding to the portion to be cut and inclinedly extending away from the electrode tab from an end of the pressing surface.