Pouch Battery Sealing Fold Layout for Insulation Resistance
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Solution Overview
Problem
The folding of the sealing part in pouch type secondary batteries leads to a reduction in insulation resistance, which is exacerbated when the sealing part is folded multiple times, posing a safety risk.
Innovation Solution
A secondary battery design with a specific folding structure for the sealing part, where the outer end is folded along defined distances and lines, optimizing the sealing range and folding positions to minimize insulation resistance defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sealing part is folded multiple times to reduce space and improve volume energy density, then the volume energy density is improved, but the insulation resistance decreases
Solution Approach 1:
The sealing part is divided into multiple folding portions (first folding portion, second folding portion, third folding portion) with distinct folding lines. Each folding portion is spaced at specific distances from each other, creating segmented folding zones that prevent insulation resistance defects while enabling multiple folds for space reduction.
Solution Approach 2:
The folding lines are pre-positioned at optimized distances from the outer end of the sealing part (first distance, second distance, third distance) before folding occurs. This preliminary positioning ensures that when folds are made, the sealing portions maintain proper spacing and do not cause insulation resistance reduction, even before the actual folding action takes place.
2Volume of stationary object
If the sealing part is folded to improve space utilization, then the space occupation is reduced, but the insulation resistance defect increases
Solution Approach 1:
Different portions of the sealing part are assigned different functions through localized quality variations. The first, second, and third folding portions are positioned at specific distances from the outer end, creating localized folding zones with optimized spacing. This local quality differentiation ensures that folding occurs in specific regions without affecting the insulation resistance of other regions.
Solution Approach 2:
The invention optimizes specific parameters including the distances between folding lines (first distance, second distance, third distance) and the positions of folding portions relative to the outer end of the sealing part. By changing these spatial parameters to specific optimized values, the sealing part can be folded multiple times for space reduction while maintaining insulation resistance.
3Productivity
If the sealing part is folded multiple times to minimize space, then the space efficiency is improved, but the manufacturing precision requirement increases
Solution Approach 1:
The folding lines are pre-positioned at optimized distances from the outer end of the sealing part (first distance, second distance, third distance) before folding occurs. This preliminary positioning establishes clear reference points that guide the folding process, making it easier to achieve precise folds during manufacturing while maintaining the required spacing between folding portions.
Solution Approach 2:
The sealing part structure itself provides the folding lines as inherent features at specific distances from the outer end. These self-defined folding positions serve as built-in guides that automatically ensure proper spacing between folds, reducing the need for external precision control mechanisms and simplifying the manufacturing process.
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 optimized folding structure maintains insulation resistance even after multiple folds, preventing insulation defects and ensuring high-temperature storage durability and sealing performance.
Implementation Method 1
a portion from the outer end of the sealing part to the sealing line is sealed by fusion
Data Source
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AI summary
The present invention relates to a secondary battery including: an electrode assembly; and a pouch type exterior including an accommodation part, which accommodates the electrode assembly, and a sealing part provided to surround at least a portion of the accommodation part to seal the accommodation part, wherein the sealing part includes: a first folding portion provided so that an outer end of the sealing part is folded toward the accommodation part along a first folding line spaced a first distance from the outer end of the sealing part toward the accommodation part; and a second folding portion provided so that the first folding portion is folded toward the accommodation part along a second folding line spaced a second distance from the first folding line toward the accommodation part, wherein, when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the accommodation part is referred to as a sealing line, the sealing part includes a sealed portion in which a portion from the outer end of the sealing part to the sealing line is sealed by fusion, wherein, when a distance from the outer end of the sealing part to the accommodation part is referred to as a width of the sealing part, a distance from the sealing line to the accommodation part is 45% to 55% of the width of the sealing part.