Apparatus for folding a separator into a Z-shape and method for fabricating an electrode / separator arrangement configuration.
The apparatus efficiently folds separators into a Z-shape using movable rails and pushers, addressing the challenge of complex bar removal and ensuring stable, high-speed production of electrode-separator configurations in battery cells.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MERCEDES BENZ GROUP AG
- Filing Date
- 2023-11-07
- Publication Date
- 2026-06-03
AI Technical Summary
Existing methods for folding electrodes and separators in battery cells face challenges such as complex bar removal, which can cause electrodes to slip, leading to defective production, especially in solid-state batteries, and struggle to balance high production speed with efficient folding techniques.
An apparatus with movable rails and pushers clamps and cuts a longitudinally extending strip-shaped separator into a Z-shape, using heated or cutting bars to fix the separator in place, allowing for efficient folding and removal of bars without damaging the material.
Enables high-speed production of Z-shaped electrode-separator arrangements with improved stability and reduced defects by ensuring secure fixation and efficient bar removal, suitable for both stackable and non-stackable separators.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an apparatus for folding a longitudinally extending strip-shaped separator in a zigzag shape for an electrode / separator arrangement configuration of individual battery cells. Furthermore, the present invention relates to two different methods for producing an electrode / separator arrangement configuration in a stacked form using such an apparatus.
Background Art
[0002] The production of electrode / separator arrangement configurations is widely known from common prior art. In fact, three manufacturing methods have become established, which are described, for example, in Non-Patent Document 1. This document describes substantially the stacking of individual separator sheets and electrodes, as well as the winding of electrodes and separators. Another method is the so-called zigzag folding, which is generally referred to as "Z-folding". For this, a seamless separator is used, with one electrode placed on top of the separator, after which the separator is folded back or folded over the electrode, and subsequently, the next sheet-shaped electrode is placed, but this next sheet-shaped electrode has the opposite polarity to the other. Subsequently, the separator is folded back again and the next electrode is placed, and this process is repeated. At this time, the separator is continuously supplied as a roll material and must be moved back and forth accordingly. The advantage of stacking or Z-folding is that, unlike winding, the electrodes are not curved, which can be a decisive advantage especially in solid-state batteries. The advantage of winding is that a very high production speed can be achieved, which cannot be achieved by the continuously performed processes of stacking and Z-folding.
[0003] Patent Document 1 describes a method substantially as described at the beginning, in which the separator for an individual battery cell in which the electrodes are stacked is folded via a movable bar to form a stacked zigzag-folded electrode for a battery cell.
[0004] Furthermore, Patent Document 2 describes a similar process for creating an electrode stack configuration in which electrodes and separators are folded in a Z-shape. Another method of this type is basically known from Patent Document 3. Finally, see Patent Document 4, which also addresses this subject and basically discloses an apparatus for folding a stack of electrodes into an f-shape. Both methods share the commonality that the bar used for folding into a Z-shape must be removed again from the stacked or folded material. This is relatively complex. For this reason, the prior art, for example in the aforementioned Patent Document 2 and similarly in Patent Document 4, shows and describes pulling it out laterally. This is always a problem when the electrodes and separators are joined but not yet fixed in place, because in that case the electrodes may slip within the stack, which can lead to defective production. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Japanese Patent Publication No. 2003-243270 [Patent Document 2] Japanese Patent Publication No. 2009-140776 [Patent Document 3] German Patent Application Publication No. 102018200958 [Patent Document 4] Japanese Patent Publication No. 2012-033275 [Non-patent literature]
[0006] [Non-Patent Document 1] Literature “Process and Performance Optimization by Selective Assembly of Battery Electrodes”, Jan Schmitt et al., CIRP Annals-Manufacturing Technology 63 (2014)9-12 [Overview of the project] [Problems that the invention aims to solve]
[0007] Therefore, the object of the present invention is to provide an apparatus for folding a separator into a Z-shape, which enables a high production speed, and a suitable method for manufacturing an electrode-separator arrangement configuration. [Means for solving the problem]
[0008] According to the present invention, this problem is solved by an apparatus having the features of claim 1, in particular the feature portion of claim 1. Advantageous configurations and variations of the apparatus according to the present invention become apparent from the claims dependent on claim 1. Solutions regarding the method are shown in the method of claim 5 and the alternative method described in claim 6.
[0009] In other words, the apparatus according to the present invention is used to fold a longitudinally extending strip-shaped separator into a Z-shape for the electrode separator arrangement configuration of individual battery cells. The apparatus includes two presses, which are designed to clamp a separator, cut to a length suitable for the method, at both ends in the longitudinal direction. A mounting fixture is positioned between the two presses, which is equidistant from each other in the longitudinal direction and includes bars that extend in a direction transverse to the longitudinal direction. These mounting fixtures are housed in rails in the longitudinal direction and are movable from those rails in the longitudinal direction. The rails themselves are movable in the height direction transverse to both the longitudinal and transverse directions. That is, the rails can move away from each other or towards each other. The individual bars, viewed in the longitudinal direction, are alternately positioned above and below the clamping position of the separator in the height direction. In other words, when the separator is sandwiched between the pushers, one bar is positioned above the separator and the other bar is positioned below it, alternating between the two. As the rails move away from each other, the fixtures connected to the rails exert a corresponding force on the bars, so the separator is pulled downward by half of the bar and upward by the other half. In this case, the positions of the two pushers also change to move closer to each other. This is because the separator here forms a Z-shaped folded strip, and therefore, considering only the longitudinal direction, the separator is considerably shorter. At the end positions of the pushers and rails, the rails have moved to their maximum distance from each other, and the pushers have moved to their maximum distance from each other, so the Z-shaped folded separator bundle is positioned between the pushers.
[0010] Herein, according to the present invention, a cutting device is provided for cutting a separator in a region of the bar where the bar is configured to be heatable and / or where the presses are moved to be as close to each other as possible.
[0011] In one variant, the bars are also configured to be heatable. This is particularly important in stackable separators, where the bars can be stacked into a single unit by a heated press. This is also possible in principle in other separators.
[0012] In the finished product, the bars are undesirable. Since these bars can be heated, for example, the bars can be removed from the separator by heating them and then moving the rail beyond its end position. This melts the separator in the folding region and pulls the bars out of the separator in a direction transverse to the direction of movement through the molten material. At the same time, the molten portion is then melted together by the pressure applied from the press, which helps to fix the unit in place of or complement to the heated press.
[0013] As an alternative or complement to this, a cutting device for cutting the separator can be provided in the area of the bar at a position where the presses are moved in a direction that brings them as close to each other as possible. Such a cutting device is useful for removing the bar appropriately, complementing or substituting the use of a heated bar. Here, the cutting can be done mechanically, for example, via a knife, rolling cutter, etc., or a laser can be used for cutting. These techniques are particularly suitable when a non-layerable separator is used and the material in the separator cannot be melted and / or cut by heat without damage.
[0014] Here, according to a highly advantageous development of the apparatus according to the present invention, the length of the bar in the transverse direction is formed to be greater than the width of the separator. Such a wide bar improves the quality of folding and enables, for example, a mounting configuration in which the mounting fixture holds the bar at both ends in the transverse direction, thereby allowing a uniform tensile force to be applied to the separator through the bar when the rails are moved away from each other.
[0015] According to another highly advantageous configuration of the apparatus according to the present invention, the press can be configured to be heatable. By being able to heat the press in this manner, in particular, after the press is abutted at its end position, the separator can be laminated by heating so that the separator is melted to a certain extent, thereby bonding the individual regions of the separator together, thereby forming a fixed unit consisting of the separator and typically a pre-introduced electrode.
[0016] In order to appropriately adjust the procedure of the apparatus and enable the separator to be folded into a Z shape in this apparatus, a highly advantageous configuration of the apparatus according to the present invention allows the apparatus to have a control unit that adjusts the movement of the pusher and rails, and in particular the control unit is set to move the rails away from each other as described above and move the pusher towards each other in order to fold the separator, and these movements are carried out by appropriately adjusting the rails and pusher.
[0017] In a method according to the present invention for fabricating a stacked electrode-separator arrangement configuration for individual battery cells with consecutive separators, in one method step, electrodes are stacked on the separator. Here, on each longitudinal surface of the separator, the electrodes are followed by a gap having at least the length of the electrode. This allows the electrodes and gaps to be alternated along the longitudinal direction of the separator, so that after folding, each layer of separator on which the electrodes are stacked is located on one side of the electrodes, and another layer with a gap is folded over the electrodes. In this case, furthermore, each surface of the separator is arranged with electrodes of the same polarity, for example, the anode on the upper side and the cathode on the lower side. Electrodes of different polarities are located at least partially on opposite sides on each surface. In this context, "at least partially" means, for example, that if the number of anodes is different from the number of cathodes, then in order to make the folding complete, only one of those electrodes is present on one side of the end region of the separator. After such a semi-finished product is fabricated from a separator and stacked electrodes, in a second method step, the semi-finished product is folded into a Z shape by moving the rails and pushers to their respective end positions in one apparatus of the above configuration, as already suggested. From the semi-finished product, an electrode-separator arrangement configuration is produced which is formed to include a Z-shaped folded separator.
[0018] According to another method of the present invention, the stacking of electrodes can be omitted, for example, when non-stackable separators are used. In this case, in the first method step, in the apparatus with the above configuration, the rails and pushers move toward each end position, but stop before reaching each end position so that the separators are folded in advance. In this case, the separators are folded in a Z shape, but they exist so as to have relatively large open pockets, which are oriented either up and down or to the sides, depending on the arrangement configuration of the apparatus. Subsequently, for example, all electrodes are inserted into the corresponding pockets simultaneously, or in two consecutive steps, first all anodes and then all cathodes are inserted into the corresponding pockets, for example, the cathodes from below and the anodes from above, or in a rotated arrangement configuration, the cathodes from the left and the anodes from the right, respectively. Subsequently, in the third method step, the rails and pushers move toward each end position. Here again, without having to fabricate semi-finished products from electrodes and separators beforehand, a suitable Z-shaped folded electrode-separator arrangement is created.
[0019] In any method according to the present invention, stackable separators can be used. In this case, in another method step, the apparatus can be fixed at the end position of the press to form a single unit, and for this purpose, in a corresponding configuration, the press can be heated in the sense described above, so that the unit is formed by stacking the separators. Alternatively, another method for fixing to form a unit can be applied, for example, by injecting adhesive from the side of a Z-shaped folding portion that is open on the side. In particular, if the separators do not need to be stacked or fused, adhesive tape can be used for fixing.
[0020] According to the present invention, when there is such a fixed unit, the separator is separated in the bar region of the fixed unit, whereby the bar is removed from the unit. This can be done, in the sense described above, for example by cutting using mechanical means or a laser, or by heating the bar and moving the rails of the device so that they move away from each other beyond the end position, whereby the bar is pulled through the molten material of the separator.
[0021] Another very advantageous configuration of the device according to the present invention and of the method according to the present invention will become apparent from the embodiments described in more detail below with reference to the drawings.
Brief Description of the Drawings
[0022] [Figure 1] A side view of the device according to the present invention in the starting position is shown. [Figure 2] A front view taken along line II-II in FIG. 1 is shown. [Figure 3] An intermediate position of the pusher and the rails, shown as in FIG. 1, is shown. [Figure 4] A front view taken along line IV-IV in FIG. 3 is shown. [Figure 5] An end position of the pusher and the rails, shown as in FIG. 1, is shown. [Figure 6] A front view taken along line VI-VI in FIG. 5 is shown.
Embodiments for Carrying Out the Invention
[0023] Based on the following figures, and using the separator 1 with stacked electrodes 2 as seen in Figure 1 as an example, the procedure for creating a z-shaped folded electrode-separator arrangement will be explained. Here, the separator 1 is sandwiched between two presses 3 in the longitudinal direction x. Here, a first electrode 2, for example, an anode 2.1, is placed on one surface of the separator 1 located on the upper side in the height direction z, and a cathode 2.2 is placed on the lower surface. Between the electrodes, there are always empty sections of the separator 1, and these sections have a length of at least the length of the adjacent electrode 2 in the longitudinal direction x. Here, only the anode 2.1 is placed in the section shown on the far right, and the cathode 2.2 is omitted.
[0024] In addition to the side view in Figure 2, this structure can also be seen in the front view shown in Figure 2, which follows the line II-II in Figure 1. Here again, we can see the separator 1 having an anode 2.1 on the upper side in the height direction z and a cathode 2.2 on the lower side in the height direction z. Here, in the longitudinal direction x, two rails extend above and below the separator 1, and as shown in Figure 1, multiple mounting fixtures 5 are arranged on these rails, with only two of these mounting fixtures 5 being labeled with reference numbers. As can be seen from Figure 2, these mounting fixtures 5 can be attached to the sides of the rails in the transverse direction y. These mounting fixtures 5 are movable in the longitudinal direction x relative to the rails 4. Here, the mounting fixture 5 itself has a bar 6, which extends in the transverse direction y, and can be seen particularly in Figure 2. These bars 6, as can be seen particularly in Figure 1, are always arranged alternately above and below the separator 1 in the height direction z, and are always positioned in the boundary region between the area with electrodes 2 and the section without electrodes.
[0025] The z-shaped folding of separator 1 to obtain the desired electrode-separator configuration is initiated by the pressing tools 3 moving toward each other on one side, so that in each of the figures shown here, the pressing tool 3 shown on the left moves toward the right. At the same time, the two rails 4 move toward each other, thereby applying tensile force to the separator at corresponding points via the mounting fixtures 5 and bars 6. After this movement of the device, which is attached to the whole, is initiated, the device is in the position shown in Figures 3 and 4, as shown in Figures 1 and 2. Here again, as seen from the left pressing tool 3 shown in Figure 4, one of the electrodes, here the anode 2.1, is shown on separator 1. In order to perform the accordion-like z-shaped folding of separator 1, the rails 4, and thus the bars connected to the rails 4 via the mounting fixtures 5, move toward each other vertically. Each of the individual mounting fixtures 5 moves toward the right pressing tool 3 in the longitudinal direction x, thereby obtaining the desired configuration of separator 1.
[0026] This method, in which the rails 4 are pulled apart from each other and the pushers 3 move toward each other, is continued until the end positions of the pushers 3 and rails 4 shown in Figure 5 are reached. The two pushers 3 sandwich the electrode-separator arrangement configuration between them, and can be heated, for example, to produce a stackable separator 1 consisting of the separator 1 and the electrode 2. Finally, the bar 6 is removed from the unit, for example, by separating the separator 1 in the area of the bar 6, which can be done mechanically with a knife or preferably by heating the bar 6. The heated bar is pulled out of the unit by moving the rails 4 beyond their end positions. The molten separator can then be brought together again, and the unit can be closed to a reasonably tight degree.
[0027] In the alternative configuration described at the beginning, where the electrodes 2 are not stacked on the separator 1, the movement of the pusher 3 and rail 4 will be appropriately stopped at an intermediate position of the device 10 between the two positions shown in Figures 3 and 5, in order to insert the electrodes into the pockets, for example, to insert all electrodes 2 simultaneously, or in each figure, to first insert the anode 2.1 from above and then the cathode 2.2 from below. Subsequently, it will move to the end position shown in Figure 5. Instead of melting or heating the separator 1 to form the unit, the lateral bonding of the separator ends can be done here by means of adhesive, adhesive tape, etc. Subsequently, the bar 6 can be removed by cutting the separator 1, for example, and then reattached using adhesive tape, for example.
Claims
1. A device (10) for folding a strip-shaped separator (1) extending in the longitudinal direction (x) into a z-shape for the arrangement of electrodes and separators in individual battery cells, The separator (1) is provided with two pressing tools (3) for clamping it at both ends in the longitudinal direction (x), In the apparatus (10), a mounting fixture (5) is provided between the two pressing devices (3), the mounting fixture (5) is at the same distance from each other in the longitudinal direction (x) and has a bar (6) in the transverse direction (y) that extends in a direction that traverses the longitudinal direction (x), and two rails (4) are formed which are movable in the height direction (z) that traverses the longitudinal direction (x) and the transverse direction (y), the rails (4) are provided at a position higher and lower than the separator (1) in the height direction (z), respectively, when viewed in the longitudinal direction (x), the bar (6) is alternately arranged above and below the clamping position of the separator (1) in the height direction (z), and moves in accordance with the movement of the rails (4) in the height direction (z), The apparatus (10) is characterized in that the mounting fixture (5) is attached to the rail (4) which extends in the longitudinal direction (x) so as to be movable along the longitudinal direction (x), and the bar (6) is configured to be heatable and / or a cutting device for cutting the separator (1) is provided in the area of the bar (6) at a position where the pressing tools (3) are moved to be as close to each other as possible.
2. The apparatus (10) according to claim 1, characterized in that the length of the bar (6) in the transverse direction (y) is greater than the width of the separator (1) in the transverse direction (y).
3. The apparatus (10) according to claim 1 or 2, characterized in that the pressing tool (3) is configured to be heatable.
4. The apparatus (10) according to claim 1 or 2, characterized by a control unit for adjusting the movement of the pusher (3) and the rail (4), wherein the control unit is configured to move the rail (4) away from each other and move the pusher (3) closer to each other in order to fold the separator (1).
5. A method for fabricating a stacked electrode-separator arrangement configuration for individual battery cells, each having a continuous separator (1), In the first method step, the electrodes (2) are stacked on the separator, and on each longitudinal (x) surface of the separator (1), the electrodes (2) are followed by a gap having at least the length of the electrodes (2), and on each surface of the separator (1), electrodes of the same polarity are arranged, and the electrodes of different polarities are at least partially opposite each other on each surface. In a subsequent second method step, the semi-finished product consisting of the separator (1) and the electrode (2) stacked thereon is folded into a Z shape by the rail (4) and the pusher (3) which are moved to their respective end positions within the apparatus (10) according to claim 1 or 2. In a subsequent method step, the stacked electrode-separator arrangement is fixed at the end position of the press (3) to form a unit. The method, characterized in that, in the fixed unit, the separator (1) is separated in the area of the bar (6) in order to remove the bar (6) from the unit.
6. A method for fabricating a stacked electrode-separator arrangement configuration for individual battery cells, each having a continuous separator (1), In the first method step, the separator (1) is pre-folded in a z-shape by the rail (4) and the pusher (3) which are moved in the direction of each end position and stopped before reaching each end position within the apparatus (10) according to claim 1 or 2, In a subsequent second method step, one electrode (2) of one polarity is simultaneously inserted into the pocket of the Z-shaped folded separator (1) from one side, and the other electrode (2) of the other polarity is simultaneously inserted into the pocket of the Z-shaped folded separator (1) from the other side, or multiple electrodes (2) of different polarities are simultaneously inserted into the pockets of the Z-shaped folded separator (1) from both sides. In a subsequent third method step, the rail (4) and the pusher (3) are moved to their respective end positions. In a subsequent method step, the stacked electrode-separator arrangement is fixed at the end position of the press (3) to form a unit. The method, characterized in that, in the fixed unit, the separator (1) is separated in the area of the bar (6) in order to remove the bar (6) from the unit.