Battery Cell Separator Handling via Vacuum Belt Transport
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Solution Overview
Problem
Existing methods for manufacturing battery cells with stacked electrodes and separators often alter the physical properties of the separators and require pre-cut sheets, leading to inefficiencies and potential changes in electrochemical properties.
Innovation Solution
A device comprising a vacuum belt for transporting separator film webs, a laser welding and cutting device for connecting and cutting the separators around electrode sheets without altering their active surface, and a contour recognition system for precise pocket formation, allowing for the production of half-cells with varied shapes and reproducible electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separator sheets are pre-cut before assembly, then handling and positioning becomes easier, but the physical properties of the separators may be altered and manufacturing precision is reduced
Solution Approach 1:
The separator films are prepared in advance as continuous webs with pre-defined active and inactive areas, but the actual cutting and pocket formation is performed later during the assembly process itself. This preliminary preparation of the web structure allows easy handling during assembly while maintaining the integrity of the separator material until the final cutting stage.
Solution Approach 2:
The cutting operation is extracted and performed selectively only in the inactive areas of the separator films, using a laser that can precisely distinguish between active and inactive zones. This allows the separator material in the active areas to remain untouched and preserve its physical properties, while still enabling easy handling and positioning through the cutting of inactive regions.
2Device complexity
If a single laser device is used for both welding and cutting, then device complexity is reduced, but the precision of both operations may be compromised
Solution Approach 1:
A single laser device is designed to perform multiple functions: welding the separator films together in the inactive areas, forming pockets around the electrode sheets, and cutting the half-cells from the continuous web. The laser system can switch between these different operations by adjusting its parameters and movement patterns, eliminating the need for separate welding and cutting devices while maintaining precision through programmable control.
3Strength
If separator films are connected by traditional welding methods, then the separator structure may be damaged, but connection strength is reduced
Solution Approach 1:
Traditional mechanical welding or bonding methods are replaced with laser-based welding. The laser provides localized thermal energy that melts and fuses the separator film material without requiring mechanical pressure or contact tools. This substitution eliminates mechanical stress and potential damage from physical handling during the connection process, while still achieving strong bonds between the separator films in the inactive areas.
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
Enables the production of battery cells with preserved separator properties and flexible electrode sheet shapes, maximizing packing efficiency and maintaining electrochemical integrity, while eliminating the need for pre-cut sheets and minimizing mechanical or thermal stress on the electrodes.
Implementation Method 1
The vacuum belt initially holds and transports the first web of separator film. The placed electrode sheets are then also held and transported by the vacuum belt just like the second separator sheet web, since the vacuum also sucks in the electrode sheets and the second separator sheet web through the pores of the first separator sheet web.
Implementation Method 2
The device for connecting the separator films is a laser welding device, which is also the laser cutting device. The pockets for the electrode sheets are produced by a weld seam.
Implementation Method 3
The cutting device is a laser cutting device that is able to cut out differently shaped half-cells. The half-cells are cut out close to the edge of the pocket for the electrode sheet, so that half-cells can be produced with only a small overhang of the film.
Data Source
Figure 1
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AI summary
A device for producing a battery cell having an electrode stack which is made of at least one half cell (18, 18'), wherein the half cell (18, 18') is formed by two separator films (11, 15; 11', 15') and an electrode sheet (14, 14') arranged in a pocket between the separator films (11, 15; 11', 15'), characterized by a holder for a roll (22) of a first separator film web (11), a vacuum belt (13) onto which the first separator film web (11) can be placed, a handling device for placing at least one electrode sheet (14) onto the first separator film web (11), a holder for a roll (21) of a second separator film web (15), a device (19) for connecting both separator films (11, 15) outside the electrochemically active area of the electrode sheet (14) and a cutting device (20) for cutting out half cells (18) from the connected separator film webs (11, 15).