Heated Roller Separator Bonding for Unit Cell Cutting Stability
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Solution Overview
Problem
In existing secondary battery manufacturing processes, separators can fold during cutting, leading to potential short circuits due to inadequate bonding between upper and lower separators, especially when not properly cut.
Innovation Solution
A method and apparatus using oval-shaped upper and circular lower rollers to thermally fuse and bond the upper and lower separators before cutting, ensuring they are sealed together, preventing folding and potential short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the separator is cut by applying vertical pressure through a cutter, then the separator is divided into individual unit cells, but the separator may fold when not properly cut, causing short circuits
Solution Approach 1:
The patent applies preliminary bonding action by heating and pressing the separators together before the cutting operation. The heating press applies heat and pressure to bond the separators to the electrodes, creating a stable structure that prevents folding during subsequent cutting. This preliminary bonding ensures the separator maintains its position and shape throughout the cutting process.
2Device complexity
If the upper and lower separators are not bonded before cutting, then the cutting process is simpler, but the separators may fold during cutting leading to short circuits
Solution Approach 1:
The patent changes the physical parameters of the separator bonding process by applying heat and pressure. The heating press increases the temperature to melt the adhesive layer and applies mechanical pressure to bond the separators to the electrodes. This parameter change transforms the separators from a unstable, fold-prone state to a stable, bonded state that prevents folding during cutting.
3Strength
If heat and pressure are applied through a laminating device to bond electrodes and separators, then bonding is achieved, but the separator may still fold during subsequent cutting
Solution Approach 1:
The patent introduces an intermediary heating press that specifically targets the separator regions for bonding. This heating press acts as a mediator between the laminating device and the separator, applying localized heat and pressure to ensure the separator is firmly bonded to the electrodes at the cutting positions. This intermediary action provides additional stability to the separator during the cutting 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
Prevents separator folding and subsequent short circuits by effectively bonding the separators before cutting, enhancing the reliability and integrity of the unit cell manufacturing process.
Implementation Method 1
at least one of the lower roller or the upper roller is heated to a predetermined temperature to thermally fuse points at which the upper separator and the lower separator are pressed
Data Source
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Figure 3(A)~3(B)
AI summary
The present invention relates to an apparatus for manufacturing a unit cell, which cuts a lower separator and an upper separator between electrodes adjacent to each other in a process of manufacturing the unit cell provided in a state, in which the lower separator and the upper separator continuously move in a longitudinal direction, and the electrodes are stacked between the lower separator and the upper separator and on the upper separator, respectively, the apparatus comprising: a lower roller disposed under the lower separator; and an upper roller which is disposed above the upper separator so as to be vertically aligned with the lower roller and has an oval shape with a long axis and a short axis, wherein, when the electrodes pass while the upper roller rotates, the upper roller is not in contact with the upper separator, and after the electrodes pass, the upper roller presses the upper separator and the lower separator to a surface of the lower roller, and at least one of the lower roller or the upper roller is heated to a predetermined temperature to thermally fuse points at which the upper separator and the lower separator are pressed.