Pouch Battery Lead-Film Laser Sealing for Uniform Edge Bonds
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Solution Overview
Problem
Existing methods for manufacturing pouch-type secondary batteries face challenges in ensuring uniform sealing quality and reducing sealing time, particularly due to the complex shape of the lead film region, which complicates temperature control and increases equipment costs.
Innovation Solution
A two-stage sealing process is employed, where a laser beam is used to first fuse the lead film to the pouch, followed by a conventional sealing tool to complete the seal, utilizing a laser unit with a compression part to transmit the laser beam and a heating bar to compress the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stacking type winding mechanism is used to wind electrodes in sequence, then winding efficiency and productivity are improved, but it becomes difficult to maintain consistent winding tension and winding quality
Solution Approach 1:
The electrode stack is divided into multiple individual electrode pieces that are wound sequentially. Each electrode piece is processed independently through the winding mechanism, allowing for consistent tension control on each segment while maintaining high overall productivity through continuous stacking operation.
Solution Approach 2:
The electrodes are pre-assembled into a stacked configuration before winding begins. This preliminary stacking arrangement ensures that each electrode is properly positioned and aligned, enabling the winding mechanism to maintain consistent tension and quality throughout the winding process without requiring complex real-time adjustments.
2Quantity of substance
If multiple electrodes are stacked and wound in sequence to increase battery capacity, then energy storage increases, but the risk of foreign object inclusion and internal stress increases
Solution Approach 1:
The electrode stacking and winding operations are performed within an inert atmosphere environment (typically nitrogen or argon). This prevents oxidation and contamination of the electrodes during assembly, significantly reducing the risk of foreign object inclusion while allowing multiple electrodes to be stacked and wound in sequence to increase battery capacity.
3Quantity of substance
If multiple electrodes are stacked and wound in sequence to increase battery capacity, then energy storage increases, but internal stress and deformation increase
Solution Approach 1:
Electrodes are pre-assembled into a stacked configuration with proper alignment and spacing before the winding process begins. This preliminary arrangement ensures that when multiple electrodes are wound in sequence, the internal stress is distributed evenly and deformation is minimized, allowing increased battery capacity without compromising structural stability.
Solution Approach 2:
The winding mechanism applies uniform tension across all stacked electrodes simultaneously or in a controlled sequential manner. This equipotential tension distribution prevents localized stress concentration and deformation, enabling the stacking of multiple electrodes to increase capacity while maintaining internal stress balance and structural integrity.
Data Source
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AI summary
A method for manufacturing a pouch-type secondary battery according to an embodiment of the present invention may include: a first sealing operation of fusing a lead film, which is attached to an electrode lead of an electrode assembly, to a sealing portion of a pouch in which the electrode assembly is accommodated; and a second sealing operation of sealing the sealing portion of the pouch. The first sealing operation may include: a heating process of irradiating with a laser beam a region which is present in the sealing portion of the pouch and corresponds to the lead film, thereby heating the lead film and melting a resin layer of the region; and a bonding process of compressing the region, thereby bonding the lead film and the melted resin layer.