Device for stacking flat articles

Abstract

The invention relates to a device for stacking flat articles. For stacking flat articles, the device according to the invention has a stacking wheel (10, 20) with stacking fingers (S1, S2) and compartments (F1, F2) between the stacking fingers for receiving flat articles (G) to be stacked, a transport device (T) for transporting flat articles into the compartments of the stacking wheel, a stripper (30) for removing flat articles from the compartments of the stacking wheel, a holder (31) for depositing flat articles removed from the compartments of the stacking wheel and for forming a stack (40) of flat articles, wherein the device has at least one first stacking wheel (10) arranged on a first shaft (12) and at least one second stacking wheel (20) arranged on a second shaft (22), wherein the shafts of the stacking wheels are parallel to one another in the axial direction and are spaced apart from one another by a distance d, such that a center point (11) of the first shaft and a center point of the second shaft lie in a plane (E), wherein the first and second stacking wheels are driven at the same speed and in the same direction of rotation (R), such that an opening formed between the first and second compartments is obtained as a function of the angular position of the first and second stacking wheels, wherein the sections of the opening between the first and second compartments which are oriented perpendicularly to the plane (E) at the respective angular positions narrow by the distance d, while the sections of the opening between the first and second compartments which are oriented parallel to the plane at the respective angular positions do not change in their opening width.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device for stacking flat objects. BACKGROUND

[0002] Stacks of flat objects, such as electrode elements, are known. In this case, at least one first electrode element and one second electrode element are used, which are arranged in a stacking position, so that an electrode stack is generated. Electrode elements for the production of electrochemical energy stores, such as lithium-ion batteries, or energy converters, such as fuel cells, are usually stacked in this way, in particular in the production of soft-pack batteries, which is a widely used design of lithium-ion rechargeable batteries.

[0003] The electrode elements are usually designed here as cathodes, for example based on aluminum foil, and / or anodes, for example based on copper foil. The smallest unit of each lithium-ion cell consists of two electrodes and a separator, which separates the electrodes from one another. After filling, an ion-conducting electrolyte is located between them.

[0004] During the stacking process, the electrode elements are stacked in a repeating cycle of anode, separator, cathode, separator, etc.

[0005] In addition to other steps of the production of electrochemical energy stores or fuel cells, such as packaging or contact communication, the stacking step is a bottleneck in the manufacturing capacity during production.

[0006] Known methods for stacking electrode elements rely on a robot's gripping arm, which grips and places the electrode elements. However, according to current knowledge, no significant speed increase is to be expected here.

[0007] Further known methods for stack formation rely on a rotating stacking wheel, by means of which the electrode elements are placed on the electrode stack.

[0008] In this regard, WO 2020 / 212316 A1 describes a method for producing an electrode stack consisting of anodes and cathodes for lithium-ion batteries for electric cars, wherein the anodes and cathodes are transported into compartments of a rotating or rotatably driven stacking wheel, and the anodes and cathodes accommodated in the compartments are transported by the rotating stacking wheel to a holder. Furthermore, it is known from WO 2020 / 212317 A1 to stack so-called single cells. This is an electrode composite consisting of anodes and cathodes and a separator for separating the electrodes.

[0009] For the production of electrochemical energy stores or energy converters it is necessary to stack flat items, in particular electrodes or single cells, which on the one hand are less flexible and on the other hand are susceptible to damage. As in the known prior art, problems arise if a high conveying speed of the electrodes or single cells into the compartments of the stacking wheel is used. For this purpose, in the known stacking wheels relatively sharply curved compartments are provided which deform the flat items to be stacked during insertion into the compartments, thereby producing the desired braking effect. However, due to the mechanical action of the compartments of the stacking wheel on the flat items or their edges, these items can be damaged. Due to the low flexibility and the relatively strong curvature of the compartments, it can also occur that the flat items cannot be inserted into the compartments of the stacking wheel completely or quickly enough, so that a fault occurs in the stacking of the flat items. SUMMARY

[0010] The technical problem to be solved is therefore to provide a device for stacking flat items by means of which the flat items can be stacked by a stacking wheel without the above-mentioned disadvantages.

[0011] According to the invention, the technical problem is solved by a device for stacking flat items having the features according to the independent claims.

[0012] The device for stacking flat items according to the invention comprises a stacking wheel having stacking fingers and compartments between the stacking fingers for accommodating flat items to be stacked, a conveying device for conveying the flat items into the compartments of the stacking wheel, a stripper for removing the flat items from the compartments of the stacking wheel, a holder for receiving the flat items removed from the compartments of the stacking wheel and for forming a stack of flat items, wherein at least one first stacking wheel mounted on a first shaft and at least one second stacking wheel mounted on a second shaft are provided, wherein the shafts of the stacking wheels are arranged axially parallel to each other and at a distance d from each other, such that a center point of the first shaft and a center point of the second shaft lie in a plane, wherein the first stacking wheel and the second stacking wheel are driven at the same speed and in the same direction of rotation, such that an opening formed between the first and the second compartment is obtained depending on the angular position of the first and the second stacking wheel, wherein a section of the opening between the first and the second compartment which is oriented perpendicularly to the plane at the respective angular position narrows at a distance d, while a section of the opening between the first and the second compartment which is oriented parallel to the plane at the respective angular position does not change in its opening width.

[0013] The invention is based on the knowledge that in the arrangement of the first and the second shaft together with the first and the second stacking wheel staggered at a distance d, the change in the geometry of the opening formed between the first and the second compartment of the first and the second stacking wheel is the same for each compartment when the stacking wheels complete a full rotation.

[0014] The advantages of the invention can be considered to be the fact that it is thus possible to feed flat articles to be stacked into the compartments of the first and second stacking wheels when the openings synthesized at the outer circumference of the stacking wheels are large. As the stacking wheels are further rotated, the opening geometry created between the compartments of the stacking wheels changes in such a way that the openings are narrowed and the flat articles fed into them can thus be braked and / or clamped. After a rotation of 180°, the opening geometry between the compartments of the stacking wheels has large openings formed again, making it possible to remove the flat articles from the compartments of the stacking wheels without too much resistance. BRIEF DESCRIPTION OF DRAWINGS

[0015] Further advantages of the invention result from the dependent claims and the following description of embodiments with reference to the drawings.

[0016] In the drawings:

[0017] Figure 1 An embodiment of an apparatus for stacking flat articles is shown in a three-dimensional view,

[0018] Figure 2 An embodiment of an apparatus for stacking flat articles is shown in a three-dimensional view, Figure 1 An embodiment of an apparatus for stacking flat articles is shown in a three-dimensional view,

[0019] Figure 3A , Figure 3B , Figure 3C An embodiment of an apparatus for stacking flat articles is shown in a three-dimensional view, Figure 2 An embodiment of an apparatus for stacking flat articles is shown in a three-dimensional view, DETAILED DESCRIPTION

[0020] Figure 1 and Figure 2 An embodiment of an apparatus 1 for stacking flat articles G to form a stack of flat articles by means of at least one first stacking wheel 10 and at least one second stacking wheel 20 is shown.

[0021] The two first stacking wheels 10 shown are mounted on a first shaft 12, which is driven, for example, via a toothed belt 13, and drives the first stacking wheels 10 in a rotational direction R at a predetermined rotational speed. The two second stacking wheels 20 shown are mounted on a second shaft 22, which is driven, for example, via a toothed belt 23, and drives the second stacking wheels 20 in a rotational direction R at a predetermined rotational speed, the rotational direction R and the rotational speed of the first and second shafts 12, 22 being identical.

[0022] The first and second stack wheels 10, 20 shown each have a predetermined number of stack fingers S1 and S2, in the example shown 10 each. Adjacent stack fingers S1 and S2 enclose compartments F1 and F2 in a predetermined number, in the example shown 10 each. The two first stack wheels 10 are mounted on the first shaft 12 in such a way that the ten first compartments F1 are aligned with one another, i.e. the first stack fingers S1 and the first compartments F1 of the two first stack wheels 10 are oriented in such a way that they are congruent when viewed in the axial direction relative to the first shaft 12. The two second stack wheels 20 are also mounted on the second shaft 22 in such a way that the ten second compartments F2 are aligned with one another, i.e. the second stack fingers S2 and the second compartments F2 of the two second stack wheels 20 are oriented in such a way that they are congruent when viewed in the axial direction relative to the second shaft 22.

[0023] The two shafts 12, 22 of the device 1 are arranged parallel to one another in the axial direction. The center points 11 and 21 of the first and second shafts 12 and 22 each lie in a plane E and have a distance d from one another.

[0024] As described above, the two stack wheels 10 and 20 are each mounted on the first and second shafts 12 and 22 in such a way that the compartments F1 and F2 are aligned with one another. This also applies to the first compartments F1 of the first two stack wheels 10 relative to the second compartments F2 of the two second stack wheels 20, i.e. the first and second stack wheels 10 and 20 are arranged on the first and second shafts 12 and 22 in such a way that, without the distance d between the center points 11 and 21 of the first and second shafts 12 and 22, the orientation of all stack fingers S1, S2 and all compartments F1, F2 of all first and second stack wheels 10 and 20 is such that they are congruent in the axial direction viewed relative to an imaginary common shaft.

[0025] If the two shafts 12, 22 are driven at the same rotational speed and in the same direction of rotation R as described above, the flat articles G conveyed by the conveying device T can be conveyed and inserted into the compartments F1, F2 while the stack wheels 10, 20 are rotated at the same rotational speed in the direction of rotation R. The stack wheels 10, 20 convey the flat articles G located in the compartments F1, F2 to the holder 31. The device 1 for stacking flat articles G also has one or more strippers 30 which are arranged laterally next to the stack wheels 10, 20 and which strip the flat articles G conveyed in the compartments F1, F2, that is to say remove them from the compartments F1, F2, so that the flat articles G are deposited on the holder 31 and form a stack 40 of flat articles G. If a particularly large stack has to be formed, the holder 31 can be moved in the direction of the arrow 32 so that the holder 31 or the stack 40 formed thereon does not collide with the stack fingers S1, S2.

[0026] Figure 3 shows an enlarged detail of Figure 2The local parts A, B and C are marked.

[0027] From Figure 3A It can be seen that in the area of the local part A between the stacking fingers of the first and second stacking wheels 10, 20, the largest opening 3A is formed for the compartments of the stacking wheels 10 and 20 located at this point. From Figure 2 It can be seen that the flat article G is fed from the conveying system T into the compartments Fl, F2 of the stacking wheels 10, 20 at the location of the largest opening 3A in the compartments Fl, F2 of the first and second stacking wheels 10, 20. This means that the flat article G can be inserted into the compartments Fl, F2 without the risk of colliding with the stacking fingers S1, S2, since the compartments have the largest opening 3A at this point of the outer circumference of the stacking wheels.

[0028] From Figure 3B It can be seen that after a rotation of 90° the smallest opening 3B in the compartments Fl, F2 is created in the area of the local part B. This means that the flat article G in the compartments Fl, F2 is clamped by the stacking fingers S1, S2 or at least subjected to a force at this location of the smallest opening. The continuous reduction of the opening in the compartments Fl, F2 enables the braking of the flat article G fed by the conveying device T into the compartments Fl, F2 of the stacking wheels 10, 20, without suddenly exerting a greater force on the flat article G or its edges, which could lead to damage to the flat article, when the stacking wheels 10, 20 are rotated in the direction of rotation R at the same speed.

[0029] After a further rotation of 90°, as Figure 3C shown in the area of the local part C, the largest opening 3C of the compartments of the stacking wheels 10 and 20 at this point is again obtained. In this way, the stripper 30 can remove the flat article G located in the compartments of the stacking wheels 10 and 20 without too much resistance from the stacking fingers S1, S2 of the stacking wheels 10 and 10, so as to deposit the article on the holder 31.

[0030] The variation of the opening between the compartments Fl, F2 of the first and second stacker wheels 10, 20 during the rotation of the first and second stacker wheels 10, 20 in the rotation direction R is due to the arrangement of the two shafts 12, 22 of the device 1 in axial parallel to each other, wherein the center points 11 and 21 of the first shaft 12 and the second shaft 22 are located in a plane E and have a distance d from each other. By this arrangement of the shafts 12, 22 of the stacker wheels 10, 20, the maximum opening of the compartments Fl, F2 of the first and second stacker wheels 10, 20 is always formed when the compartments Fl, F2 are oriented parallel to the plane E in which the center points 11, 21 of the shafts 12, 22 are located. The minimum opening of the compartments Fl, F2 is always formed when the compartments Fl, F2 are oriented perpendicular to the plane E during the rotation of the first and second stacker wheels 10, 20 in the rotation direction R. In the embodiment shown in the figures, the plane E is vertical and horizontal in the view plane. Thereby, the maximum opening in the compartments Fl, F2 of the first and second stacker wheels 10, 20 is formed in case the compartments Fl, F2 of the two stacker wheels 10, 20 are oriented horizontally in the area of the transport device T (part A) and the stripper 30 (part C). Correspondingly, the minimum opening in the compartments Fl, F2 of the first and second stacker wheels 10, 20 is formed when the compartments Fl, F2 of the two stacker wheels 10, 20 are oriented vertically in the area of the toothed belt 13 and the part C. Or in other words, the overall geometry of the opening between the first and second compartments Fl, F2 depends on the angular position of the first and second stacker wheels 10, 20, wherein the section of the opening between the first and second compartments Fl, F2 which is perpendicular to the plane E at the respective angular position is narrowed by the distance d (minimum opening), while the section of the opening between the first and second compartments Fl, F2 which is parallel to the plane E is constant (maximum opening). In all other angular positions of the section of the opening between the first and second compartments Fl, F2 which is not exactly parallel or perpendicular to the plane E, the opening has a value between the minimum and maximum opening.

[0031] The maximum opening corresponds to the minimum opening in one of the compartments Fl or F2. The minimum opening is obtained by subtracting the distance d of the center points 11, 21 from the first and second shafts 12, 22 from the minimum opening in one of the compartments Fl or F2. For example, if the compartments Fl and F2 of the first and second stacker wheels 10 and 20 each have a continuous opening with a width of 5 mm and the distance d is 4 mm, a maximum opening of 5 mm and a minimum opening of 1 mm are generated.

[0032] Figure 1 and Figure 2The compartments of the illustrated stack wheels 10, 20 have a curved profile. In contrast thereto, the compartments can also have a straight, helical or other profile. The profile of the compartments is advantageously adapted to the properties of the flat articles G to be stacked. If the flat articles G are, for example, flexible and slightly bendable or deformable, it can be advantageous to select a higher curved or helical profile for the compartments. If the flat articles G are, for example, rigid and only slightly or hardly bendable or deformable, it is advantageous to select a straight or only slightly curved profile for the compartments.

[0033] In the embodiment described with reference to the drawings, the first and second stack wheels 10 and 20 have the same design. The first and second stack wheels 10 and 20 can also have different designs. For example, the first stack wheel 10 can have compartments F1 and stack fingers S1 which differ in size from the second stack wheel 20 and its compartments F2 and stack fingers S2 and / or have a different profile. It is essential in the design of the first and second stack wheels that the above-mentioned properties of the flat articles to be stacked are taken into account, and that the above-mentioned connection of the first and second stack wheels 10 and 20 to the first and second shafts 12 and 22 is such that the profiles of the first and second compartments F1 and F2 are congruent in the region of the transport device T to the extent that the compartments F1 and F2 have the greatest opening in the region of the transport device T, so that the flat articles G can be transported into the compartments F1 and F2. The same applies to the region of the stripper 30 which removes the flat articles G from the compartments F1 and F2. As mentioned above, just as in the case of different designs of the stack fingers and compartments of the first and second stack wheels 10 and 20, the smallest opening in the compartments F1 and F2 is in each case formed in the region which is 90° from the region of the transport device T and the stripper 30 in the direction of rotation R.

[0034] In addition, the stack wheels 10, 20 can be mounted on their respective shafts 12, 22 with slight rotational play. In this case, the opening produced in the compartments F1, F2 decreases in dependence on the rotation of the stack wheels 10, 20. However, this leads to a further increase in the braking effect of the stack wheels 10, 20 on the flat articles to be stacked.

[0035] Furthermore, the first and second stacking wheels 10 and 20 or their stacking fingers S1 and S2 can be made of the same or different materials. For example, the first stacking wheel 10 or its stacking fingers S1 can be made of a relatively rigid, slightly flexible material, such as aluminum, while the second stacking wheel 20 or its stacking fingers S2 can be made of a more flexible material, such as PMMA. In this case, the dimensions of the compartments F1 and F2 can be defined such that the resulting minimum opening is smaller than the thickness of the flat articles to be stacked. It can also be provided that the minimum opening results in a negative value. For example, the two compartments F1 and F2 can have an opening of 3 mm in width, and the distance d of the center points 11, 21 of the shafts 12, 22 can be 4 mm. As a result, for a maximum opening of 3 mm, for the minimum opening, i.e. the intersection of the stacking fingers S1, S2 of the first and second stacking wheels 10, 20, a value of -1 mm is obtained. In this case, by selecting different materials for the stacking fingers S1, S2 of the first and second stacking wheels 10 and 20, the flat articles G to be stacked are particularly strongly braked or clamped in the region of the minimum opening, which, as mentioned above, is negative, between the flexible and rigid fingers S2 and S1 of the first and second stacking wheels 10 and 20, and the flexible stacking fingers S2 of the second stacking wheel 20 are deformed. Thereby, the flat articles are particularly safely conveyed in the stacking wheels, and the stacking is particularly precisely formed.

[0036] The above-mentioned dimensions of the compartments F1, F2 of the first and second stacking edges 10, 20, which result in a minimum opening smaller than the flat articles G to be stacked or are negative, can also be used for the rigid stacking fingers S1 and S2 of the first and second stacking wheels 10 and 20 if the flat articles G are stacked, since in this case the flat articles G are deformed in the region between the first and second stacking wheels 10, 20.

[0037] Furthermore, the stacking fingers S1, S2 of the first and / or second stacking wheels 10, 20 can be equipped with a soft, sliding or slidable surface in order to influence the braking effect on the flat articles G conveyed into the compartments F1, F2 and to minimize the acting forces during the movement of the stacking fingers S1, S2 relative to each other when the stacking wheels 10, 20 are rotated. Materials with corresponding properties are, for example, plastic materials such as polyethylene terephthalate (PET), polyoxymethylene (POM), polyamide and polytetrafluoroethylene (PTFE), as well as rubber-like materials such as ethylene-propylene-diene rubber (EPDM) or silicone, or even brush-like surface structures.

[0038] In the embodiment shown in the figures, two first stack wheels 10 and two second stack wheels 20 are provided, respectively. However, it is obvious that only first and second, or more than two first and second stack wheels 10 and 20 can be used, as long as the compartments F1 and F2 of the stack wheels 10 and 20 are oriented such that flat objects G can be transported from the transport device T into the compartments F1 and F2 of the stack wheels 10 and 20, as described above.

[0039] It is also obvious that the arrangement of the first and second shafts 12 and 22 used can have a design different from the embodiment shown in the figures, as long as the above-mentioned distance d between the shafts is made and the center points 11, 21 of the shafts 12, 22 lie in one plane. In contrast to the embodiment shown, the plane E does not have to be horizontal in the view plane, but can have any desired deviation. If the shafts 12, 22 are arranged, for example, such that their center points 11, 21 lie in a plane that is offset by 30° with respect to the plane E shown, the sections A, B and C are offset by 30° in the opposite direction to the direction of rotation R. Figure 2

[0040] Between the shafts 12, 22 of the stack wheels 10, 20, force- applying elements F, for example springs, can be provided. In this case, the springs F pull or push the shafts 12, 22 away from or towards each other. One of the shafts 12, 22 can also have a fixed position. Due to the force of the springs F and the offset distance d of the shafts 12, 22, a force is exerted on the flat objects G to be stacked via the shafts 12, 22 during a revolution of the stack wheels 10, 20. This increases the frictional force between the flat objects G to be stacked and the stacking fingers S1, S2 of the stack wheels 10, 20, which leads to the possibility of further adjustment of the clamping force and / or frictional force acting on the flat objects G to be stacked.

[0041] As mentioned at the beginning, the flat objects G can be electrode elements for the production of electrochemical energy stores, for example lithium-ion batteries, or energy converters, for example fuel cells. They have an anode and a cathode and a separator or membrane. They are stacked individually or as single cells, for example as described in WO 2020 / 212316 A1 or WO 2020 / 212317 A1. A predetermined number of anodes and cathodes and separators or membranes or single cell chambers must be stacked in order to be able to form an energy store or energy converter. This can be achieved particularly advantageously by means of the above-described device.

[0042] The above-described device is also suitable for other delicate flat objects, such as banknotes, to form stacks of the respective flat objects.​

Claims

1. A device (1) for stacking flat articles (G), comprising stacking wheels having stacking fingers and compartments between the stacking fingers for receiving flat articles (G) to be stacked, a conveying device (T) for conveying flat articles (G) into the compartments of the stacking wheels, a stripper (30) for removing flat articles (G) from the compartments of the stacking wheels, and a holder (31) for depositing flat articles (G) removed from the compartments of the stacking wheels and for forming stacks (40) of flat articles (G), characterized in that the stacking wheels have at least one first stacking wheel (10) arranged on a first shaft (12) and at least one second stacking wheel (20) arranged on a second shaft (22), the compartments comprise first compartments and second compartments, wherein the shafts of the stacking wheels are arranged axially parallel to one another and at a distance d from one another, such that a center point (11) of the first shaft (12) and a center point of the second shaft (22) lie in a plane (E), wherein the first stacking wheel and the second stacking wheel are driven at the same speed and in the same direction of rotation (R) such that an opening formed between the first compartments and the second compartments is obtained depending on the angular position of the first stacking wheel and the second stacking wheel, wherein a section of the opening between the first compartments and the second compartments oriented perpendicularly to the plane (E) at the respective angular position narrows at the distance d, while a section of the opening between the first compartments and the second compartments oriented parallel to the plane (E) at the respective angular position does not change in its opening width.

2. Apparatus for stacking flat articles according to claim 1, characterized in that, The compartments of the first and second stacking wheels have a curved, straight or helical profile along their contour or a section of the contour.

3. Apparatus for stacking flat articles according to any one of claims 1 or 2, characterized in that, At least one stacking wheel or at least its stacking fingers are composed of a rigid material.

4. The apparatus for stacking flat articles according to claim 1, characterized in that, At least one stacking wheel or at least its stacking fingers are composed of a flexible material.

5. The apparatus for stacking flat articles according to claim 1, characterized in that, At least one stacking wheel or at least its stacking fingers have a soft, sliding or slidable surface.

6. The apparatus for stacking flat articles according to claim 1, characterized in that, The first and second stacking wheels are identically configured.

7. The apparatus for stacking flat articles according to claim 1, characterized in that, The first and second stacking wheels are configured differently.

8. The apparatus for stacking flat articles according to claim 1, characterized in that, Between the first and second shafts there is arranged an element (F) which exerts a force between the first and second shafts.

9. The apparatus for stacking flat articles according to claim 1, characterized in that, The compartments of the first and second stacking wheels or at least a section of the compartments have an opening whose width is greater than or equal to the distance d and the thickness of the flat articles (G) to be stacked.

10. The apparatus for stacking flat articles according to claim 1, characterized in that, The compartments of the first and second stacking wheels or at least a section of the compartments have an opening whose width is less than the distance d and the thickness of the flat articles (G) to be stacked.

11. The apparatus for stacking flat articles according to claim 1, characterized in that, Between the first and second shafts there is arranged a spring.

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