Pouch Battery Corner Protection During Degassing and Resealing
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Solution Overview
Problem
Existing methods for manufacturing pouch-shaped battery cells struggle to prevent deformation and cracking of corner portions during the manufacturing process, leading to high defect rates and safety concerns.
Innovation Solution
A method involving the use of a protective film with an adhesive layer and a film layer made of nylon or PET-based compounds is applied to the corner portions of the electrode assembly receiving portion. This film is attached to maintain the shape of the corner portions throughout the manufacturing process, including degassing and resealing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sealing portions are formed in advance at corner portions of the electrode assembly receiving portion, then crumples can be prevented at the corner portions in the early stage of manufacture, but the corner portions cannot be prevented from being deformed by stress repeatedly concentrated thereon in subsequent degassing and resealing processes
Solution Approach 1:
The protective film is attached to the corner portions of the electrode assembly receiving portion before the degassing and resealing processes. This preliminary protective measure ensures that when stress is applied during subsequent manufacturing steps, the corner portions are already shielded and can maintain their shape without deformation or cracking.
Solution Approach 2:
The protective film acts as a cushioning layer that absorbs and distributes the stress concentrated on the corner portions during degassing and resealing processes. By providing this protective barrier in advance, the film prevents the metal layer from cracking while allowing the manufacturing processes to proceed normally.
2Ease of manufacture
If the metal layer of the laminate sheet is used to form the battery case, then the battery case can be easily formed and gas/moisture blocked, but cracks may form at the corner portions of the electrode assembly receiving portion due to stress concentration
Solution Approach 1:
Instead of changing the entire battery case structure, the protective film is applied specifically to the corner portions of the electrode assembly receiving portion where stress concentration occurs. This localized protection maintains the overall ease of manufacture while preventing cracks at the critical corner areas.
Solution Approach 2:
The solution combines the metal layer (for formability and barrier properties) with the protective film (for crack prevention). This composite approach allows the metal layer to maintain its ease of formation while the protective film provides additional protection against stress-induced cracking at the corner portions.
3Productivity
If cracks are formed at the laminate sheet corner portions, then the battery can be manufactured, but electrolytic solution may leak out or external moisture may be introduced, reducing battery safety
Solution Approach 1:
The protective film is attached before the degassing and resealing processes that could cause cracking. By providing this protective barrier in advance, the film prevents cracks from forming in the metal layer, thereby preventing electrolyte leakage and moisture intrusion while allowing normal manufacturing productivity.
Solution Approach 2:
The protective film serves as a cushioning layer that prevents stress concentration from causing cracks in the metal layer. This beforehand protection ensures the integrity of the battery case, preventing harmful factors such as electrolyte leakage and moisture intrusion while maintaining manufacturing output.
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
The method significantly reduces the defect rate of pouch-shaped battery cells by preventing cracks at the corner portions and minimizing the risk of electrolyte leakage and ignition.
Implementation Method 1
a protective film 120, wherein an inner surface of the protective film 120 is attached to an outer surface of the corner portion 112 in tight contact therewith
Data Source
Figure 1(a)~1(e)
Figure 2
Figure 3
AI summary
The present invention relates to a method of manufacturing a pouch-shaped battery cell, the method including (a) receiving an electrode assembly in a preliminary battery case and sealing other outer peripheries of the preliminary battery case excluding a first side outer periphery of the preliminary battery case, through which gas is discharged, (b) attaching a protective film to at least one corner portion of an electrode assembly receiving portion, (c) performing an activation process and a degassing process, (d) resealing a first side outer periphery of the electrode assembly receiving portion, and (e) removing the protective film, wherein the inner surface of the protective film is attached to the outer surface of the corner portion of the electrode assembly receiving portion in tight contact therewith without being crumpled in order to support the shape of the corner portion of the electrode assembly receiving portion, which is technology capable of preventing the preliminary battery case from being deformed by force continuously applied to the preliminary battery case in a process of manufacturing the pouch-shaped battery cell.