Laminating apparatus for laminating multilayer endless webs for producing energy cells

Abstract

The invention relates to a laminating apparatus for a multilayer endless web (3) composed of at least one separator web (4, 6) and at least one electrode for producing energy cells using a pressing device which laminates the multilayer endless web (3) over a pressing surface by exerting a compressive force. The pressing surface has various portions having a different spring stiffness.

Description

[0001] Laminating device for laminating multi-layer continuous webs for the production of energy cells

[0002] The present invention relates to a laminating device for

[0003] Laminating of multi-layer continuous webs for producing energy cells having the features of the preamble of claim 1.

[0004] Energy cells or energy storage devices within the meaning of the invention are used, for example, in motor vehicles, other land vehicles, ships, aircraft or also in stationary systems such as photovoltaic systems in the form of battery cells or fuel cells, in which very large amounts of energy must be stored over longer periods of time.

[0005] For this purpose, such energy cells can have a structure consisting of a plurality of segments stacked together. These segments are each formed from alternating anode sheets and cathode sheets, separated from each other by separator sheets, also manufactured as segments. The segments are pre-cut during the manufacturing process and then stacked in a predetermined order and bonded together by lamination. The anode sheets and cathode sheets are first cut from a continuous web and then individually placed at intervals onto a continuous web of separator material.This subsequently formed "double-layered" continuous web of separator material with the applied anode or cathode sheets is then cut into segments again in a second step using a cutting device. In this case, the segments are formed in a double layer by a separator sheet with an anode or cathode sheet arranged on top. If this is technically feasible or necessary from a manufacturing perspective, the continuous webs of separator material with the applied anode or cathode sheets can also be placed on top of one another before cutting, thus forming a continuous web with a first continuous layer of separator material with anode or cathode sheets applied thereon and a second continuous layer of separator material with anode or cathode sheets applied thereon.This "four-layer" continuous web is then cut into segments using a cutting device. In this case, these segments are formed in four layers, comprising a first separator sheet, an anode sheet, a second separator sheet, and a cathode sheet lying on top of it. The advantage of this solution is that one cut can be eliminated. Furthermore, the cut electrodes can also be placed on a continuous separator sheet and stacked on top of each other by another continuous separator sheet to form a three-layer continuous web, from which three-layer segments comprising a separator sheet, an electrode sheet, and another separator sheet are then cut. Segments within the meaning of this invention are therefore single-layer segments of a separator material, anode material, or cathode material, or double-layer, three-layer, or four-layer segments of the structure described above.

[0006] Furthermore, the "double-layer" or "four-layer" continuous webs described above can also be supplemented by placing another separator web on the electrodes to form a "three-layer" or "five-layer" continuous web, which then has a separator web on each side. Alternatively, the electrodes can also be present as continuous webs, i.e. uncut, in the "double-layer", "three-layer", "four-layer" or "five-layer" continuous webs, which are then cut to considerably longer lengths and then wound up, for example. Alternatively, the continuous webs can also be wound first and then cut after winding is complete. In this case, the electrodes in the continuous webs are not present as spaced-apart segments, but instead in a single segment that extends uninterruptedly into the space between the separator webs.

[0007] Furthermore, an electrode in the form of a copper track or copper foil or a comparable carrier material with an intermittent coating can also be provided in the endless track, in which the coatings each form sectional, spaced-apart elevations in the electrode.

[0008] To laminate the "double-layer," "three-layer," "four-layer," or "five-layer" continuous webs, they are passed between two pressing devices that exert a compressive force on the continuous webs. In this process, the electrodes are pressed together with the separator webs in these continuous webs. Generally, the electrodes and separator webs are bonded and laminated using a pressing device that applies a compressive force. Lamination can also be assisted by the generation of heat caused by the compressive force. Furthermore, additional heating or cooling zones can be provided to regulate the temperature of the continuous webs during lamination. To achieve a high-quality bond, it is desirable that the continuous webs be subjected to as uniform a compressive force as possible across their longitudinal and transverse extensions.

[0009] If the electrodes in the continuous webs are already arranged at intervals in the form of cut segments, the electrodes form additional gaps in the continuous webs due to their spacing. Due to their thickness, the electrodes additionally keep the separator webs at a distance from each other in the gaps. This gives the electrodes additional free edges at the edges bordering the gaps. Furthermore, the continuous web thus exhibits additional thickness variations.

[0010] Thus, the continuous web to be laminated has a varying thickness, resulting solely from the unavoidable manufacturing inaccuracies of the thicknesses of the electrodes and separator webs and / or the spacing of the electrodes. Furthermore, the electrodes can be narrower than the separator webs, resulting in varying thicknesses of the continuous web in the area of ​​the edge sections due to the arrangement of the electrodes in the continuous web.

[0011] These thickness fluctuations of the continuous web lead to dynamic stress on the pressing device in the lamination device. Furthermore, the thickness fluctuations lead to fluctuations in the pressing forces exerted by the pressing device on the continuous web and to increased compressive loads at the free edges, with the risk of edge damage. Against this background, the object of the invention is to create a laminating device that enables the lamination of the continuous webs with a contour-adapted pressing force and a reduced dynamic load on the pressing device.

[0012] According to the invention, a laminating device having the features of claim 1 is proposed to achieve the object. Further preferred developments can be found in the subclaims, the figures, and the associated description.

[0013] According to the basic concept of the invention, it is proposed that the pressing surface has different sections with different spring stiffnesses. Due to the different spring stiffnesses, the pressing surface can be specifically designed so that it is stiffer in predetermined sections and thus transmits a higher compressive force, while transmitting a lower compressive force in the sections with the lower spring stiffness. This makes it possible, in particular, to compensate for thickness differences in the endless web due to the arrangement of the electrode in the endless web by deliberately allowing the pressing surface to yield and compress more in the sections with the lower spring stiffness than in the sections with the higher spring stiffness.As a result, thickness fluctuations have a smaller impact on the pressing force because they are compensated for by the contour-adapted pressing force, so that lamination takes place with a much more constant pressing force acting on the continuous web. By adjusting the pressing force in certain sections in synchronization with the thickness fluctuations of the continuous web, zones of higher and lower pressure can be created, thus specifically influencing the cohesion forces resulting from lamination. Particularly in areas with free edges, the pressing forces can be reduced in synchronization with the thickness fluctuations and free edges in order to avoid damage to the free edges without increasing the dynamic load on the overall system. This is done by ensuring that the pressing surface gives way and deflects more in the sections with lower spring stiffness than in the sections with higher spring stiffness.

[0014] It is further proposed that the pressing device laminate the multilayer continuous web in the lamination device by applying heat. The lamination, i.e., the bonding of the continuous webs of separator material to one another and to the electrodes, occurs when polymers penetrate from one layer into the other, which in turn is caused by the adhesion forces acting at the interfaces. These very adhesion forces can be achieved more easily by applying heat. However, care must be taken to ensure that the material at the interfaces is not compressed to such an extent by applying heat and the applied pressure that the ion exchange, which is essential for the function of the energy cell, is inhibited.

[0015] The different spring stiffnesses can preferably be achieved by resilient support of the pressing surface in the pressing device. The different spring stiffnesses achieved by the resilient support of the pressing surface can be achieved by individual resiliently mounted segments in the pressing surface in an otherwise non-resilient pressing surface, or by multiple resiliently mounted segments with different spring stiffnesses. Furthermore, the different spring stiffnesses can additionally or alternatively be achieved by different spring stiffnesses of the material of the pressing surface. This can be achieved, for example, by a locally different arrangement of stiffening material components or a locally different combination of different materials in the pressing surface and / or by dimensioning the pressing surface in different thicknesses.

[0016] It is further proposed that the electrode has a smaller width in the longitudinal direction of the endless web than the separator web, and that the pressing surface has a higher or lower spring stiffness in the area with which it covers at least one protruding edge of the separator web than in the area with which it covers the electrodes. With the proposed solution, the endless web is laminated with a higher compressive force in at least one edge area than in the area of ​​the electrodes. This results in a stronger bond of the endless web in the edge area while at the same time lowering the load on the electrodes. Furthermore, the spring stiffness can be designed to be lower instead of higher, so that the pressing surface deliberately gives way more in the area of ​​the protruding edges of the separator web.Since the endless track itself is “softer” in the area of ​​the edges of the separator track due to the lack of a resistance surface otherwise formed by the electrodes, the pressing surface deliberately exerts a lower pressing force in these sections.

[0017] It is further proposed that a plurality of regularly spaced electrodes be provided in the continuous web. The continuous web is thus prefabricated for the production of individual multi-layer segments, each with an electrode or a pair of electrodes. To produce the segments, the continuous web simply needs to be cut into the individual segments in a cutting process. If the continuous web has an intermittent coating, the coated sections correspond to the electrodes, and the distances between the coatings correspond to the distances between the electrodes.

[0018] In this case, it is further proposed that the pressing surface has a higher or lower spring stiffness in the section with which it comes into contact with the endless web in the area of ​​the gaps between the electrodes than in the section with which it comes into contact with the endless web in the area of ​​the electrodes. Due to the higher spring stiffness in the area of ​​the gaps between the electrodes, the endless web is exposed to a relatively higher pressing force in these sections than in the area of ​​the electrodes. The pressing surface can therefore deliberately give way more in the area of ​​the electrodes than in the areas of the gaps or gaps between the electrodes, so that the electrodes are protected during lamination and the separator webs are laminated better in the area of ​​the gaps.The pressing surface thus has a distribution of sections with higher spring stiffness corresponding to the arrangement of the gaps and a distribution of sections with lower spring stiffness corresponding to the distribution of the electrodes. Furthermore, the spring stiffness can be designed to be lower instead of higher, so that the pressing surface deliberately yields more in the section with which it comes into contact with the endless track in the area of ​​the gaps between the electrodes. Since the endless track itself is "thinner" in the area of ​​the gaps due to the lack of a resistance surface otherwise formed by the electrodes, the pressing surface deliberately exerts a lower pressing force in these sections.

[0019] It is further proposed that the pressing device comprise at least one pressing roller with a circular cross-section, and that the pressing surface be formed by the outer surface of the pressing roller. The proposed design of the pressing device allows the lamination device to be preferably integrated into a drum conveyor, which in turn enables a very high production capacity. The outer surface of the pressing roller also forms a particularly advantageous pressing surface, as it can be manufactured with great precision and, by rolling along the continuous web, enables linear pressing of the continuous web across its entire width.

[0020] In this case, at least one radially resiliently mounted jacket segment can be provided in the jacket surface, the radially outer surface of which forms part of the pressing surface. The pressing surface thus springs locally in the area of ​​the jacket segment, so that the compressive force for laminating the continuous web is lower in these sections. For this purpose, the jacket segments can be arranged and dimensioned such that they cover the electrodes as they roll along the continuous web, so that the electrodes are deliberately relieved of stress during lamination, or in other words, the continuous web is laminated with a higher compressive force in the area of ​​the gaps than in the area of ​​the electrodes. Furthermore, the resilient jacket segments can also be arranged such that the electrodes are specifically relieved of stress in the area of ​​their edges.

[0021] It is further proposed that the pressing device comprise at least one pressing belt, and that the pressing surface be formed by the surface of the pressing belt, with which it bears against the endless web, exerting a compressive force. The use of a pressing belt in the pressing device to create the pressing surface has the advantage that the compressive force during lamination can be generated by any pressure-generating device and distributed via the pressing belt onto the endless web in a distribution defined by the shape and design of the pressing belt. Due to its belt shape, the pressing belt has the advantage that the force transmission surface can be increased over a greater length of the endless web.

[0022] In this case, the press belt can exhibit different spring stiffnesses along its length in the direction of the applied compressive force. The press belt thus has zones that are harder and zones that are deliberately softer. The press belt can thus adapt to the thickness differences of the endless web, so that the endless web is subjected to less stress in the thicker zones. The press belt can provide improved flexibility in these zones, e.g., the zones of the system on the endless web where the electrodes are located, so that pressure peaks during lamination can be reduced.

[0023] The press roller can preferably be positioned against the free side of the press belt and press the press belt against the endless web while exerting a compressive force. In this case, the press roller is the pressure-generating device with the advantages described above, which are then combined with the advantages of using a press belt to create a further improved solution. According to an advantageous further development, it is proposed that the press roller and / or the press belts be moved and / or driven synchronously with the endless web.

[0024] By synchronizing the movement of the endless web with the press roller and / or press belts, the cohesive forces can be specifically influenced. This allows, for example, the pressing forces in areas with free edges to be reduced synchronously with thickness variations and free edges.

[0025] The invention will be explained below using preferred embodiments with reference to the attached figures.

[0026] Fig. 1 : a section of a laminating device with a four-layer continuous web and a pressing device with two press rollers; and

[0027] Fig. 2: a section of a lamination device with a three-layer continuous web and a pressing device with two press rollers and two press belts.

[0028] Figure 1 shows a section of a lamination device according to the invention, in which the continuous web 3 is formed by a "four-layer" continuous web 3 with a separator web 4 on the top side and a separator web 6 in the middle, a plurality of anodes 5 arranged between the separator webs 4 and 6, and a plurality of cathodes 7 arranged below the central separator web 6. The anodes 5 are larger than the cathodes 7, so that the anodes 5, when arranged in pairs with the cathodes 7, have a smaller end-to-end distance A from one another than the cathodes 7. The lamination device further comprises a pressing device with two press rollers 1 and 2, which are designed as cylindrical drums with a circular cross-section.The press rollers 1 and 2 are aligned with their axes of rotation parallel to each other and arranged so that between their lateral surfaces 12 and 13 there is a gap S with a gap width SW that is constant in the direction of the axes of rotation, i.e. perpendicular to the plane of representation.

[0029] The gap width SW of the gap S is smaller than the thickness D of the endless web 3, so that the endless web 3 is slightly compressed and laminated as it passes through the gap S. The thickness D2 of the separator webs 4 and 6 is each 15 to 25 pm, while the electrodes 5 have a thickness D1 of 150 to 400 pm. This results in a thickness D of the electrode web 3 of approximately 330 pm to 850 pm. The gap width SW is 20 to 100 pm, preferably 40 to 60 pm, smaller than the thickness D of the endless web, so that the endless web 3 is slightly compressed by 5 to 10 pm as it passes through the gap S. The intermediate spaces 8 are formed by the spacing of the electrodes and have a height which corresponds to the thickness D1 of the electrodes, i.e. 150 to 400 pm.Furthermore, the gaps 8 have a length in the feed direction corresponding to the distance A of the electrodes 5 of 3 mm between the anodes and 6 mm between the cathodes, whereby it is desirable to keep the distances A between the electrodes 5 as small as possible in order to increase the material utilization rate of the endless web 3 and the number of electrodes 5 in a predetermined length of the endless web 3. The endless web 3 is transported in the feed direction T and pulled through the gap S. The press rollers 1 and 2 can themselves be actively driven, for example by individual drives in the form of servo motors, to the opposite rotary movements directed in the direction of the arrow P, so that they additionally actively transport the endless web 3 through the frictional engagement. Alternatively, the press rollers 1 and 2 can also be only rotatably mounted, so that they themselves are driven by the endless web 3 through the frictional engagement to the rotary movements.In this case, the press rollers 1 and 2 only roll passively on the surfaces of the endless web 3.

[0030] The outer surfaces 12 and 13 of the press rollers 1 and 2 form the pressing surfaces of the pressing device. The outer surface 12 of the upper press roller 2 is spring-loaded by several springs F1 to F5 with different spring stiffnesses, so that it yields differently depending on the rotational angle of the press roller 2 and the resulting contact position on the endless web 3. The same applies to the lower press roller 1 in the illustration with its springs F6 to F10, which act on the outer surface 13.

[0031] Figure 2 shows an alternative embodiment of the invention. In addition to the two press rollers 1 and 2, the press device here also comprises two press belts 20 and 21, which rest against the top and bottom of the endless web 3. The press rollers 1 and 2 are identical to the press rollers 1 and 2 in Figure 1 and rest against the free surfaces of the two press belts 20 and 21.

[0032] Furthermore, a continuous web 3 to be laminated is provided, which runs through the gap S and has a thickness D. The continuous web 3 is formed by a "three-layer" continuous web 3 with a separator web 4 on the top side and a separator web 6 on the bottom side, with anodes 5 arranged between them. The anodes 5 are arranged with gaps 8 at identical distances A from one another and have a smaller width than the separator webs 4 and 6, so that the separator webs 4 and 6 project laterally beyond the anodes 5.

[0033] Since the anodes 5 are generally larger than the cathodes 7 in the energy cell, but the separator tracks 4 and 6 are identical and serve to arrange both the anodes 5 and the cathodes 7 shown in Figure 1, the distances A of the spaces 8 between the cathodes 7 and the free lateral edge zones of the cathodes 7 are particularly large. Conversely, the distances A of the spaces 8 and the free edge zones of the anodes 5 are smaller.

[0034] The springs F1 to F10 in the press rollers 1 and 2 are dimensioned such that the pressing surfaces formed by the outer surfaces 12 and 13 are deliberately stiffer in certain sections of the circumference and deliberately softer in other sections, by the springs F1 to F10 having different spring stiffnesses. This allows the pressing surfaces to yield differently in the event of unavoidable thickness fluctuations in the endless web 3, for example, due to the gaps 8. This allows the endless web 3 to be laminated with lower pressure peaks and a reduced load on the electrodes 5, particularly in the area of ​​the edges adjacent to the gaps 8.

[0035] In the embodiment of Figure 2, in addition to the press rollers 1 and 2, two additional press belts 20 and 21 are provided. In accordance with the embodiment of Figure 1, a plurality of springs F1 to F10 with different spring stiffnesses are provided in the press rollers 1 and 2. Alternatively or additionally, the press belts 20 and 21 can also be designed with different spring stiffnesses in the direction in which the pressing forces are exerted on the endless web 3. For this purpose, the press belts 20 and 21 can be implemented, for example, as textile belts with local fiber reinforcements or other combinations of different materials. Furthermore, individual jacket segments can also be provided in the jacket surfaces 12 and 13 of the press rollers 1 and 2, which with their surfaces form a section of the jacket surface 12 and 13 and are separately spring-mounted.It would also be conceivable to use a rod carpet, a piston-cylinder unit, a pneumatically operated pressure device, e.g. with an inflatable cushion as a pressure generating device instead of the press rollers 1 and 2. In particular, fiber-reinforced textile belts, steel belts or even very fine-link belts can be used as press belts 20 and 21.

[0036] The laminating device can be designed such that the pressing device has a distribution of spring stiffnesses in the pressing surfaces adapted to a thickness distribution of the continuous web 3 to be laminated, wherein in particular the dimensions of the electrodes 5 and the position of the intermediate spaces 8 including the distances A of the electrodes in the intermediate spaces 8 are taken into account.

Claims

Claims:

1. Laminating device for a multi-layer continuous web (3) comprising at least one separator web (4, 6) and at least one electrode for producing energy cells with -a pressing device which laminates the multi-layer endless web (3) over a pressing surface by exerting a compressive force, characterized in that -the pressing surface has different sections with different spring stiffness.

2. Laminating device according to claim 1, characterized in that -the pressing device laminates the multi-layer continuous web (3) by applying heat.

3. Laminating device according to claim 1 or 2, characterized in that -the different spring stiffness is realized by a resilient support of at least one section of the pressing surface in the pressing device.

4. Laminating device according to one of claims 1 to 3, characterized in that -the different spring stiffness is achieved by different spring stiffnesses of the material of the pressing surface.

5. Laminating device according to one of claims 1 to 4, characterized in that -the electrode has a smaller width in the longitudinal direction of the endless track than the separator track (4,5), and -the pressing surface in the area with which it comes to cover at least one projecting edge of the separator track (4, 5) has a higher or lower spring stiffness than in the area with which it comes to cover the electrodes.

6. Laminating device according to one of claims 1 to 5, characterized in that -a plurality of cut electrodes arranged at regular intervals from one another are provided in the endless track (3).

7. Laminating device according to claim 6, characterized in that -the pressing surface in the section with which it comes into contact with the endless track (3) in the area of ​​the distances between the electrodes has a higher or lower spring stiffness than in the section with which it comes into contact with the endless track (3) in the area of ​​the electrodes.

8. Laminating device according to one of claims 1 to 7, characterized in that -the pressing device comprises at least one pressing roller (1, 2) with a circular cross-section, and -the pressing surface is formed by the outer surface (12,13) ​​of the pressing roller.

9. Laminating device according to claim 8, characterized in that -at least one radially resiliently mounted casing segment is provided in the casing surface (12, 13), the radially outer surface of which forms part of the pressing surface.

10. Laminating device according to one of claims 1 to 7, characterized in that -the pressing device has at least one pressing belt (20, 21), and the pressing surface is formed by the surface of the pressing belt (20, 21) with which it rests against the endless web (3) while exerting a compressive force.

11. Laminating device according to claim 10, characterized in that -the press belt (20,21) has different spring stiffnesses along its longitudinal extent in the direction of the exerted compressive force.

12. Laminating device according to claim 8 or 9 and according to one of claims 10 or 11, characterized in that -the press roller (1,2) rests on the free side of the press belt (20,21) and presses the press belt (20,21) against the endless web (3) by exerting a compressive force.

13. Laminating device according to one of claims 8 or 9 and according to one of claims 10 to 12, characterized in that -the press roller (1, 2) and / or the press belts (20, 21) are or are moved and / or driven synchronously with the endless web (3).

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