Pouch Battery Casing With Lead Grooves for Reliable Thermal Sealing
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Solution Overview
Problem
The deep drawing method for manufacturing pouch-shaped battery casings is limited by material elongation, leading to edge cracks and unfused portions at electrode lead positions, which compromises sealing and safety due to gas pressure concentration.
Innovation Solution
The battery casing is divided into a first and second casing with different sizes or shapes, and electrode lead grooves are formed to recess the electrode leads, allowing for easier formation and enhanced safety by preventing unfused portions and improving thermal fusion sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the deep drawing method is used to manufacture pouch-shaped battery casings, then the casings can be formed in a single piece, but edge cracks occur due to material elongation limits
Solution Approach 1:
The battery casing is divided into multiple separate pieces (first casing piece, second casing piece, third casing piece) instead of forming as a single piece. This segmentation reduces the elongation requirement for each individual piece, preventing edge cracks while maintaining ease of manufacture through simplified forming processes for each segment.
2Reliability
If electrode leads are positioned at the upper end of the casing body, then electrical connection is achieved, but unfused portions occur during thermal fusion sealing
Solution Approach 1:
An insulating film is introduced as an intermediary layer between the electrode leads and the casing during thermal fusion sealing. This mediator prevents direct contact between the electrode leads and casing material, ensuring complete fusion and eliminating unfused portions while maintaining proper electrical connection through the insulating film's design.
Solution Approach 2:
The electrode leads are positioned and secured in place before the thermal fusion sealing process begins. This preliminary positioning ensures that the leads remain stationary during sealing, allowing the insulating film to effectively prevent unfused portions from forming at the sealing location.
3Reliability
If insulation films are attached to electrode leads to improve sealing, then sealing is enhanced, but the process complexity increases
Solution Approach 1:
The insulating film attachment process is merged with the existing electrode lead positioning and casing assembly process. By integrating the insulation film application into the standard assembly workflow rather than treating it as a separate step, the process complexity increase is minimized while still achieving enhanced sealing quality.
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 eliminates defects in casing formation, enhances safety by reducing unfused areas, and allows for more versatile and stable battery casing design, improving sealing and structural integrity.
Implementation Method 1
the cover 121 and the opposite sides 124 and the upper end 125 of the casing body 122 come into contact with each other and then are bonded to each other when heat and pressure are applied thereto such that the resin layers are thermally fused together, whereby sealed margin portions are formed
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed in a battery cell including: an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes, with electrode tabs protruding from at least one side of outside peripheral portions of the electrode assembly; and a battery casing including first and second casings provided with first and second receiving parts, respectively, the first and second receiving parts respectively accommodating the electrode assemblies and having different sizes or shapes, wherein in a state in which electrode leads connected to the electrode tabs protrude from outside peripheral portions of the first and second casings, the battery casing is sealed by thermal fusion along the outside peripheral portions of the first and second casings, wherein electrode lead grooves recessed downwardly such that the electrode leads are seated therein are provided at a portion of the outside peripheral portions of the first and second casings.