WO2024100268A1

WO2024100268A1 - Gripping device with integrated radiation activation

Info

Publication number: WO2024100268A1
Application number: PCT/EP2023/081469
Authority: WO
Inventors: Marten Rohde; Christoph Mette
Original assignee: Tesa Se
Priority date: 2022-11-10
Filing date: 2023-11-10
Publication date: 2024-05-16
Also published as: DE102022129681A1

Abstract

The invention relates to a gripping device (10) for handling substrates (12) which are adhesively bonded using curable adhesive substances with simultaneous curing of the curable adhesive substances, comprising: i) a first gripping element (14), ii) a second gripping element (16), and iii) a gripping mechanism (18) which connects the first gripping element (14) and the second gripping element (16), wherein the gripping mechanism (18) is configured to move the first gripping element (14) and the second gripping element (16) relative to one another in a reversible and destruction-free manner, wherein the gripping device (10) is configured to grip a substrate (12) between the first gripping element (14) and the second gripping element (16) and in the process to form a positively locking and/or non-positive connection with the gripped substrate (12) in a reversible and destruction-free manner by way of movement of the first gripping element (14) and/or the second gripping element (16), wherein the first gripping element (14) and/or the second gripping element (16) are/is a curing gripping element, wherein the curing gripping element or elements comprises/comprise a main body (20) and a multiplicity of UV radiation sources (22) which are arranged on the main body (20) and are configured to irradiate a substrate (12) gripped by the gripping device (10) with electromagnetic radiation, wherein the UV radiation sources (22) have the intensity maximum of the emission at a wavelength λ in the range from 100 to 400 nm.

Description

Gripping device with integrated radiation activation

Description

The invention relates to a gripping device for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesives and a method based thereon for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesives using a corresponding gripping device. The use of a corresponding gripping device for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesives is also disclosed.

Adhesives and adhesive elements, such as adhesive tapes, are used in numerous modern manufacturing processes today. The use of corresponding adhesive technologies is not usually limited to just joining separate elements by creating material-tight connections. Adhesives and corresponding adhesive elements are also used for numerous other purposes, whereby in addition to taping openings in substrates, the surface modification of substrates, i.e. their gluing, plays a major role. The surface properties of substrates are specifically changed by sticking adhesive elements, such as self-adhesive films, to them.

In addition to the pressure-sensitive adhesive tapes that are particularly well-known in everyday life, so-called reactive adhesive tapes are also used in the industrial context. whose reactive adhesive can be cured under certain conditions. In the state intended for application, corresponding curable adhesives have not yet reached their maximum degree of crosslinking and can be cured by external influences by initiating polymerization in the curable adhesive and thereby increasing the degree of crosslinking. This changes the mechanical properties of the now cured adhesive, with the viscosity, surface hardness and strength increasing in particular.

Curable adhesives are known in the prior art and can have very different compositions from a chemical point of view. What these curable adhesives have in common is that the crosslinking reaction can be triggered by external influencing factors, for example by supplying energy, in particular by temperature, plasma or radiation curing, and/or contact with a substance that promotes polymerization, as is the case with moisture-curing adhesives, for example. Exemplary adhesives are disclosed, for example, in DE 102015222028 A1, EP 3091059 A1, EP 3126402 B1, EP 2768919 B1, DE 102018203894 A1, WO 2017174303 A1 and US 4661542 A.

Through curing, the adhesives used become solid and mechanically resilient materials. This makes it possible to advantageously form an adhesive element that is malleable in the uncured state and in many cases pressure-sensitively adhesive on the surface of a substrate and to arrange it in the desired position in order to then produce a structural material through curing.

The use of appropriate reactive adhesive tapes is therefore particularly suitable for creating a coating of the cured adhesive tape on the surface of substrates to which they are applied, which covers the underlying substrate and determines the surface properties of the substrate at the covered areas. The use of reactive adhesive tapes can be used advantageously to provide the substrates to which they are applied with a protective layer or a separating layer. This concept is used in many manufacturing areas, in particular in the Automotive industry. However, the production of appropriate protective and/or separating layers from cured adhesives is of particular importance in the area of battery production and processing, where, for example, battery arrangements made up of a large number of battery cells are assembled into larger arrangements for use in electric cars.

In this case, the separate battery cells in the arrangement must be separated from one another, whereby in addition to thermal insulation, electrical insulation is also necessary. To implement this electrical insulation, it has proven useful to stick the corresponding battery cells, in particular so-called prismatic battery cells, with an adhesive element that has a reactive adhesive mass that, after curing, forms an electrically insulating layer on the surface together with the carrier layer of the adhesive element.

Despite the undisputed application advantages of using reactive adhesive tapes to bond substrate surfaces, there are also aspects that are sometimes perceived as disadvantageous from a manufacturing point of view. This particularly applies to the curing step required for the curing of the reactive adhesive tapes. In the processes known from the state of the art, the substrate bonded with the reactive adhesive element must regularly be subjected to curing in a separate work step before further processing. In the case of radiation-curing curable adhesives in particular, this requires the use of additional equipment that can provide the electromagnetic radiation required for curing, for example UV lamps. The substrate bonded with the curable adhesive must be exposed to the corresponding electromagnetic radiation for a sufficient time in order to achieve the necessary strength of the cured adhesive before further processing of the substrate bonded in this way is efficiently possible.

In the prior art processes for bonding battery cells, this usually means, for example, that the surface of the battery cells is bonded with a reactive adhesive film and then, in a separate processing step, is exposed to electromagnetic radiation, in particular UV radiation, before the corresponding battery cell can be picked up and moved with a gripping device in order to feed it for further processing.

The additional production step of curing is therefore often seen as disadvantageous, particularly in terms of time and cost. In addition, the additional radiation sources required often require a particularly large amount of space at the workstation. In addition, it is often seen as a challenge to expose the substrates covered with curable adhesive to the electromagnetic radiation used for curing in a sufficiently uniform manner.

The primary object of the present invention was to eliminate or at least reduce the disadvantages of the prior art described above.

In particular, it was the object of the present invention to provide a device and a method to be carried out therewith, with which the handling of substrates bonded with curable adhesives in corresponding manufacturing processes, in particular in the processing of battery cells, can be carried out more time- and cost-efficiently.

One object of the present invention was to reduce the number of necessary separate work steps.

In addition, it was an object of the present invention to minimize the need for separate devices which are required in the specified method.

Furthermore, it was an object of the present invention that a particularly reliable and uniform curing of the curable adhesive masses should be possible with the devices to be specified and the corresponding methods.

In addition, it was an object of the present invention that with the device and the corresponding method to be specified, the Process safety should be improved, while ideally radiation exposure to the environment should also be minimized.

The inventors of the present invention have now found that the objects described above can be achieved if the UV radiation sources required for curing UV-curable adhesives are integrated into one or more of the gripping elements of a gripping device, so that a substrate gripped by the gripping device can be exposed to electromagnetic radiation in order to cure the curable adhesive on the surface of the bonded substrate during handling of the bonded substrate, for example during transfer and transfer to another work station, as defined in the claims. This advantageously makes it possible to carry out the necessary curing of the curable adhesive at the same time as the "handling" steps that are necessary anyway, whereby considerable time and cost savings can be achieved from the parallel execution of two work steps. Since the integration of UV activation into the gripping device means that only one device is required, the space requirement can be reduced. The arrangement of the UV lamps required for UV activation in the gripping device advantageously makes it possible to arrange the UV lamps particularly close to and under precisely defined conditions relative to the substrate, which enables a particularly controlled, reliable and uniform curing of the curable adhesive, whereby undesirable radiation of UV radiation into the environment can be reduced.

The above-mentioned objects are thus achieved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following statements.

Such embodiments, which are referred to below as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are therefore particularly preferred. Also preferred are Embodiments in which a feature of an embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred methods and uses emerge from the features of preferred gripping devices.

The invention relates in particular to a gripping device for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesives, comprising: i) a first gripping element, ii) a second gripping element, and iii) a gripping mechanism connecting the first gripping element and the second gripping element, wherein the gripping mechanism is designed to move the first gripping element and the second gripping element reversibly and non-destructively relative to one another, wherein the gripping device is designed to grip a substrate between the first gripping element and the second gripping element and thereby form a reversibly and non-destructively releasable, positive and/or non-positive connection to the gripped substrate by moving the first gripping element and/or the second gripping element, wherein the first gripping element and/or the second gripping element is a curing gripping element, wherein the curing gripping element or elements comprise a base body and a plurality of UV radiation sources arranged on the base body, which are designed to grip a substrate gripped by the gripping device to irradiate with electromagnetic radiation, whereby the UV radiation sources have the intensity maximum of the emission at a wavelength A in the range of 100 to 400 nm.

The device according to the invention is a gripping device. Gripping devices with which substrates are gripped and picked up are generally known to the person skilled in the art from the state of the art. Appropriate gripping devices are suitable for handling substrates and can be used, for example, in production lines.

The gripping device according to the invention is suitable for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesive, which is made possible by the structural features defined above. The person skilled in the art will understand that neither the curable adhesive nor the substrate bonded thereto are part of the gripping device according to the invention, but rather serve in the above disclosure of the invention to define the functionality of the gripping device according to the invention.

The gripping device according to the invention comprises at least two gripping elements, namely a first and a second gripping element. In accordance with the expert's expectations, the gripping device can carry out a gripping movement. For this purpose, the gripping device comprises a gripping mechanism by which the two gripping elements are directly or indirectly, preferably directly, connected to one another and which serves the purpose of moving the gripping elements relative to one another so that opening and closing of the gripping movement is made possible. An example of a gripping device according to the invention is one in which the gripping mechanism is a pneumatically or electrically operated gripping mechanism.

According to the invention, the gripping device is capable of gripping a substrate. In accordance with the expert's understanding, a corresponding gripping can be carried out by forming a positive and/or non-positive connection. A positive connection can be achieved, for example, by corresponding structural elements of the gripping elements engaging in complementary receptacles on the top of the substrate being gripped. In contrast to this, a non-positive connection can be obtained, for example, by the gripping elements being pressed together so strongly by the gripping mechanism that a substrate arranged between them can be held by the non-positive connection alone. A gripping device according to the invention is preferred, wherein the gripping device is designed to form an at least partially, preferably substantially exclusively, force-fitting connection to the gripped substrate.

The gripping device according to the invention is not limited in terms of the design of the gripping mechanism, provided that it enables the basic functionality described above. According to the inventors, however, it is preferred if the gripping mechanism can move both gripping elements, with a linear displacement being particularly preferred, as is known for example from so-called parallel grippers, since with this form of movement the orientation of the UV radiation sources can be better controlled during opening and closing, and in particular a design is possible in which the UV radiation sources point at the opposite gripping element during the gripping movement instead of radiating into the room, so that the environment is less exposed to UV radiation. Accordingly, a gripping device according to the invention is preferred, wherein the gripping mechanism is set up to move the first gripping element and the second gripping element simultaneously, preferably essentially uniformly. Additionally or alternatively, a gripping device according to the invention is preferred, wherein the gripping mechanism is set up to move the first gripping element and/or the second gripping element, preferably the first gripping element and the second gripping element, along a linear direction of movement or around a rotation axis, preferably along a linear direction of movement.

In gripping devices according to the invention, at least one of the gripping elements is designed in a specific form in that the corresponding gripping element comprises UV radiation sources arranged on the base body. In the context of the present invention, gripping elements equipped accordingly are referred to as curing gripping elements. This designation is based on the fact that the corresponding curing gripping elements are designed to irradiate a substrate gripped by the gripping device with electromagnetic radiation provided by the UV radiation sources. In accordance with the expert's understanding, the UV Radiation sources are electromagnetic radiation with an emission spectrum whose intensity maximum is at a wavelength in the range of 100 to 400 nm, i.e. in the UV range.

The gripping device according to the invention serves in particular to move bonded substrates and to harden the curable adhesives arranged thereon during this handling. For this purpose, gripping devices according to the invention can be designed in particular as end effectors, which can be used, for example, at the end of a robot arm, so that the resulting robot can grip and move a substrate coated with the curable adhesive while simultaneously curing the curable adhesive using UV radiation. A gripping device according to the invention is also preferred, wherein the gripping device comprises a fastening device for fastening the gripping device to an automated movement device, preferably a robot arm, wherein the fastening device is preferably arranged on the gripping mechanism, and/or wherein the gripping device comprises an automated movement device, preferably a robot arm, wherein the automated movement device is preferably fastened to the gripping mechanism via a fastening device.

In principle, the shape of the gripping elements can be chosen relatively flexibly, whereby, in the opinion of the inventors, it is particularly preferred to provide a substantially plate-shaped basic shape, since the UV radiation sources can be arranged particularly efficiently on this. In addition, the substrates to be handled, in particular prismatic battery cells, regularly have polygonal, flat sides, which can be contacted particularly efficiently by plate-shaped gripping elements. Consequently, a gripping device according to the invention is preferred, wherein the first gripping element and/or the second gripping element, preferably the first gripping element and the second gripping element, are plate-shaped. Additionally or alternatively, a gripping device according to the invention is preferred, wherein for at least one curing gripping element, preferably for all curing gripping elements, the surface of the substrate facing in the direction of the substrate to be irradiated is The base body has a circular or polygonal, preferably polygonal, in particular square, basic shape.

For many applications, it is sufficient if the gripping device according to the invention comprises only one curing gripping element. This makes it possible, for example, to cure substrates during handling that are only covered with a curable adhesive on one side. Corresponding gripping devices are relatively simple to construct. However, if the substrates to be handled are coated with a curable adhesive in several places, in many cases holistic curing is not possible with a gripping device that only comprises one curing gripping element, so that, for example, after one side has cured, a gripping would have to take place. Against this background, the inventors consider it advantageous for essentially all designs if at least two curing gripping elements are provided. A gripping device according to the invention is particularly preferred, wherein the first gripping element and the second gripping element are curing gripping elements. A gripping device according to the invention is particularly preferred, wherein the gripping device comprises at least two curing gripping elements, wherein the number of UV radiation sources arranged on the respective base bodies differs by 20% or less, preferably 10% or less, particularly preferably 5% or less, and very particularly preferably essentially not at all. A gripping device according to the invention is particularly preferred, wherein the gripping device comprises at least two curing gripping elements, wherein the curing gripping elements are designed essentially identically.

In order to ensure uniform curing over larger areas even when the curing gripping elements are in close contact with the substrate in a force-fit connection, a large number of UV radiation sources are provided in the curing gripping elements according to the invention. In this respect, the inventors propose particularly advantageous embodiments for the arrangement of these elements. A gripping device according to the invention is preferred, wherein at least one curing gripping element, preferably all curing gripping elements comprise 10 or more, preferably 50 or more, particularly preferably 100 or more, very particularly preferably 200 or more, especially preferably 300 or more, UV radiation sources. Additionally or alternatively, preferred is a gripping device according to the invention, wherein the UV radiation sources in at least one curing gripping element, preferably in all curing gripping elements, have an average distance from adjacent UV radiation sources in the range of 0.5 to 2 cm, preferably in the range of 0.75 to 1.5 cm. Additionally or alternatively, preferred is a gripping device according to the invention, wherein the UV radiation sources are arranged in 2 or more, preferably 4 or more, particularly preferably 8 or more, element rows made up of 5 or more, preferably 10 or more, particularly preferably 15 or more, UV radiation sources, wherein the element rows are preferably arranged substantially parallel to one another. Additionally or alternatively, a gripping device according to the invention is also preferred, wherein at least one curing gripping element, preferably all curing gripping elements, comprises a radiation region on the surface of the base body facing in the direction of the substrate to be irradiated, wherein the UV radiation sources are preferably arranged on the base body in such a way that they are distributed substantially uniformly in the radiation region.

The person skilled in the art will understand that in practical implementation it will be expedient to avoid direct contact between the UV radiation sources and the substrate or the curable adhesive mass, or to provide a certain distance between the UV radiation sources and the gripped substrate for the purpose of efficient irradiation of larger surfaces. In this respect, the inventors consider two embodiments in particular to be particularly advantageous, although these can also be combined with one another, at least in principle.

In a first embodiment, the irradiation of the gripped substrate takes place through holes in the surface facing the substrate, so that the UV radiation sources can be arranged on the side facing away from the substrate and virtually shine through the base body. In this embodiment, a Gripping device according to the invention, wherein at least one curing gripping element, preferably all curing gripping elements, comprises a plurality of continuous recesses on the surface of the base body facing in the direction of the substrate to be irradiated, wherein the UV radiation sources are at least partially, preferably predominantly, particularly preferably substantially completely arranged on the side of the base body facing away from the substrate to be irradiated such that they can irradiate a substrate gripped by the gripping device with electromagnetic radiation through the continuous recesses.

In a preferred embodiment, however, the UV radiation sources are sunk into the base body and arranged in one or more recesses, which can expediently be covered with a cover plate in order to create a smooth contact surface on the side intended for contact with the substrate. In the opinion of the inventors, a design in which all UV radiation sources are arranged in a large, individual receiving recess extending over significant parts of the intended contact surface is particularly advantageous, preferably as explained above, so that the boundaries of the receiving recess particularly preferably correspond to the boundaries of the radiation area. A gripping device according to the invention is particularly preferred, wherein at least one curing gripping element, preferably all curing gripping elements, comprise at least one receiving recess in the base body on the surface of the base body facing in the direction of the substrate to be irradiated, wherein the UV radiation sources are arranged at least partially, preferably predominantly, particularly preferably substantially completely, in the receiving recess, wherein the receiving recess is preferably covered by a transparent cover plate.

The inventors consider it particularly advantageous if the curing gripping elements are provided with spacer elements, by means of which a predetermined distance to the gripped substrate can be set and by which a direct contact of the substrate surface with the surface of the curing gripping elements can be prevented. In addition to an optimal adjustment of the distance between the radiation elements and the gripped substrate, this also makes it possible to avoid direct contact with the UV radiation sources or a cover plate covering these UV radiation sources, so that undesirable contamination of these elements can be reliably avoided. The spacer elements can particularly preferably be designed as rubber rings or similar elements, with the elastic properties of corresponding spacer elements advantageously contributing to the substrate being able to be gripped particularly gently by the gripping device according to the invention. In addition, numerous rubber materials have an advantageously high friction with many substrates, so that the use of spacer elements made of rubber materials promotes the formation of a force-fitting connection when gripping due to the resulting friction. A gripping device according to the invention is preferred, wherein at least one curing gripping element, preferably all curing gripping elements, comprise a spacer element, preferably made of an elastomeric plastic, in particular a rubber material, on the surface of the base body facing in the direction of the substrate to be irradiated, wherein the spacer element is designed to ensure a minimum distance between the surface of the base body facing in the direction of the substrate to be irradiated and the substrate, wherein the spacer element preferably extends as a circumferential elastomeric plastic element around the radiation area formed by the UV radiation sources.

The inventors have succeeded in specifying particularly suitable values for the distance between the UV radiation sources and the gripped substrate, with which particularly good results can be achieved in practice during curing during handling. A gripping device according to the invention is preferred, wherein at least one curing gripping element, preferably all curing gripping elements, is designed such that the UV radiation sources, after gripping a substrate, have an average distance in the range of 0.1 to 50 mm, preferably in the range of 0.2 to 20 mm, particularly preferably in the range of 0.5 to 10 mm.

In order to enable the most energy-efficient curing possible, the inventors propose that the surface of the base body facing the substrate can be equipped with radiation-reflecting elements, for example mirror surfaces, in addition to the UV radiation elements, in order to reflect the radiation imitated by the UV radiation sources, which would not hit the substrate, onto the substrate, in particular when using two or more curing gripping elements that are directed towards one another, so that, for example, UV radiation from an opposing curing gripping element can also be reflected back onto the substrate. A gripping device according to the invention is therefore preferred, wherein at least one curing gripping element, preferably all curing gripping elements, is provided in sections with radiation-reflecting elements, in particular mirrors, on the surface of the base body facing the substrate to be irradiated, wherein the radiation-reflecting elements preferably consist of polytetrafluoroethylene or are coated with it.

Depending on which UV radiation sources are used, a temperature build-up can occur in gripping devices according to the invention. Against this background, the inventors propose that the radiation device can be equipped with cooling elements in order to compensate for an undesirably strong increase in temperature. In this case, a gripping device according to the invention is preferred, wherein at least one curing gripping element, preferably all curing gripping elements, comprises one or more cooling elements for cooling the radiation device, preferably passive cooling elements.

Based on the idea described above, the inventors have succeeded in identifying a particularly advantageous embodiment of gripping devices according to the invention. The integration of the curing functionality by incorporating UV radiation sources into the gripping elements of a gripping device can be achieved in In particularly advantageous embodiments, the gripping device can also be supplemented by an optical detection unit, for example a camera that is aligned in such a way that it can register image information of the gripped substrate. This embodiment is particularly advantageous in combination with certain curable adhesives that comprise a dye whose absorption behavior and thus color impression changes during the curing reaction of the curable adhesive. In the corresponding gripping devices according to the invention, it is possible to obtain information about the curing state of the gripped substrate by means of the integrated optical detection unit by registering the absorption properties of the curable adhesive. The curable adhesives can advantageously be designed in such a way that the color change occurs after a predetermined minimum curing has been achieved. Accordingly, a gripped substrate can be picked up and, for example, moved using gripping devices according to the invention, wherein the gripped substrate is only released by the gripping device according to the invention when the UV curing that takes place at the same time has led to sufficient curing of the curable adhesive mass, which enables the desired further processing. Accordingly, a gripping device according to the invention is preferred, wherein at least one curing gripping element, preferably all curing gripping elements, comprise at least one optical detection unit, preferably a camera or a color sensor, which is set up to detect a change in the absorption behavior of the curable adhesive mass that occurs during the curing of the curable adhesive mass. Particularly preferred is a gripping device according to the invention, wherein the at least one optical detection unit is arranged on the surface of the base body facing in the direction of the substrate to be irradiated, preferably within, in particular centrally within, the radiation area formed by the UV radiation sources.

The above definition of UV radiation sources based on the maximum intensity of the emission is appropriate in accordance with the expert understanding, since many radiation sources, for example conventional lamps, also contain UV components in their emission spectrum. range. In light of the above definition, however, the person skilled in the art will readily understand that the UV radiation sources are UV emitters whose emission spectrum not only includes electromagnetic radiation in the defined wavelength range as a secondary component, but rather has the maximum intensity of the emission at this wavelength. Against this background, the person skilled in the art will also understand that the corresponding UV radiation sources are in particular dedicated UV lamps or UV LEDs, the latter being particularly preferred. Accordingly, a gripping device according to the invention is preferred, wherein the UV radiation sources are UV LEDs. Additionally or alternatively, a gripping device according to the invention is preferred, wherein the UV radiation sources have the intensity maximum of the emission at a wavelength A in the range from 200 to 390 nm, preferably in the range from 300 to 380 nm, particularly preferably in the range from 350 to 370 nm.

The invention also relates to a method for handling substrates bonded with curable adhesives while simultaneously curing the curable adhesives with a gripping device according to the invention, comprising the method steps: a) producing or providing a substrate bonded with a curable adhesive, b) gripping the bonded substrate between the first gripping element and the second gripping element of the gripping device to form a reversibly and non-destructively detachable, positive and/or non-positive connection to the gripped substrate, c) irradiating the substrate gripped by the gripping device with electromagnetic radiation emitted by the UV radiation sources of the curing gripping elements with a wavelength A in the range of 100 to 400 nm to cure the curable adhesives and to obtain a substrate with cured adhesive, and d) Dissolving the reversibly and non-destructively detachable, positive and/or non-positive connection between the gripping device and the substrate with cured adhesive.

The person skilled in the art will understand that in practice it will mostly be a process according to the invention, wherein the curing of the curable adhesive mass takes place with electromagnetic radiation whose intensity maximum is at wavelength A. Analogous to the above statements, a process according to the invention is preferred, wherein the curing of the curable adhesive mass takes place with electromagnetic radiation of a wavelength A in the range from 200 to 390 nm, preferably in the range from 300 to 380 nm, particularly preferably in the range from 350 to 370 nm.

The method according to the invention is particularly suitable for handling and bonding prismatic battery cells. Accordingly, a method according to the invention is also preferred, wherein the substrate is a battery cell, preferably a prismatic battery cell.

Relevant for most cases is a method according to the invention, wherein the position of the gripped substrate is changed by the gripping device during method step c), wherein the gripped substrate is preferably transferred from one work station of a manufacturing process to another work station.

The inventors have succeeded in identifying preferred curing conditions with which excellent results can be achieved in processes according to the invention for a wide range of typical curable adhesive elements, whereby the inventors propose that the adaptation of the processes according to the invention to the respective application requirements in practice can be carried out on the basis of these values. A process according to the invention is preferred, wherein the irradiation is carried out with a radiation dose in the range from 1 to 12 J/cm ² , preferably in the range from 2 to 11 J/cm ² , particularly preferably in the range from 3 to 10 J/cm ² . In addition or alternatively, a process according to the invention is preferred, wherein the curing of the curable adhesive for a time in the range of 0.5 to 60 s, preferably 1 to 30 s, particularly preferably 2 to 15 s.

It can be seen as a great advantage of the method according to the invention that it is very flexible with regard to the curable adhesive elements used, provided that these, as defined above, can be cured with the electromagnetic radiation emitted by the UV radiation sources. In other words, it is a method according to the invention, wherein the curable adhesive is a radiation-curing adhesive, in particular a UV-curing adhesive, wherein the radiation-curing adhesive is preferably curable by irradiation with electromagnetic radiation with a wavelength in the range from 100 to 400 nm, particularly preferably in the range from 200 to 390 nm, very particularly preferably in the range from 300 to 380 nm, particularly preferably in the range from 350 to 370 nm.

In practice, many of the curable adhesive elements will also comprise a carrier layer in addition to the adhesive layer for handling reasons. The person skilled in the art will understand that this carrier layer will usually be arranged between the adhesive to be cured and the UV radiation sources when the gripping device according to the invention grips the substrate coated in this way. In this respect, the carrier layer should in most cases be designed in such a way that radiation-based curability is ensured. This is possible, for example, by using porous materials, although designs with a carrier layer are preferred which are at least partially, preferably predominantly, particularly preferably substantially completely transparent for the wavelength used, as can be implemented, for example, with suitable plastic films. Accordingly, a method according to the invention is preferred, wherein the substrate is bonded with a curable adhesive element, preferably a curable adhesive film, wherein the curable adhesive element comprises: x) an adhesive layer made of the curable adhesive, and y) a carrier layer, wherein the carrier layer is at least partially transparent to electromagnetic radiation of wavelength A.

The person skilled in the art understands that the advantage of the method according to the invention is that the gripped substrate can be cured with the UV radiation sources. Accordingly, it is considered particularly advantageous to drive this curing sufficiently far during handling so that the resulting substrate with the cured adhesive can then be further processed in an advantageous manner. Accordingly, a method according to the invention is preferred, wherein the curable adhesive in method step c) is cured to more than 50%, preferably to more than 70%, particularly preferably to more than 90%, very particularly preferably to more than 95%, based on the maximum possible degree of curing.

With regard to the handling properties when bonding the substrate, it is preferred for essentially all embodiments if the curable adhesive is designed as a pressure-sensitive adhesive, since this enables easy positioning and fixing of the corresponding curable adhesive elements on the substrate even before curing, and repositioning of the adhesive elements is also possible in order to correct errors in positioning if necessary, for example. A method according to the invention is particularly preferred, wherein the curable adhesive is a pressure-sensitive adhesive.

In accordance with the expert understanding, a pressure-sensitive adhesive is an adhesive that has pressure-sensitive adhesive properties, regardless of any curability, i.e. the ability to form a permanent bond to an adhesive substrate even under relatively light pressure. Such pressure-sensitive adhesive tapes can usually be removed from the adhesive substrate after use without leaving any residue and are generally permanently self-adhesive even at room temperature, which means that they have a certain viscosity and tackiness so that they wet the surface of a substrate even under light pressure. The pressure-sensitive adhesive of a pressure-sensitive adhesive tape results from the fact that a pressure-sensitive adhesive is used as the adhesive. Without wishing to be bound by this theory, It is often assumed that a pressure-sensitive adhesive can be considered an extremely viscous liquid with an elastic component, which consequently has characteristic viscoelastic properties that lead to the permanent inherent tack and pressure-sensitive adhesive ability described above. It is assumed that with corresponding pressure-sensitive adhesives, mechanical deformation leads to both viscous flow processes and the build-up of elastic restoring forces. The viscous flow serves to achieve adhesion, while the elastic restoring forces are particularly necessary to achieve cohesion. The relationships between rheology and pressure-sensitive tack are known in the art and are described, for example, in "Satas, Handbook of Pressure Sensitive Adhesives Technology", Third Edition, (1999), pages 153 to 203. To characterize the degree of elastic and viscous components, the storage modulus (G') and the loss modulus (G") are usually used, which can be determined by means of dynamic mechanical analysis (DMA), for example using a rheometer, as disclosed, for example, in WO 2015/189323. In the context of the present invention, an adhesive is preferably understood to be pressure-sensitively adhesive and thus a pressure-sensitive adhesive if, at a temperature of 23 °C in the deformation frequency range of 10° to 10 ¹ rad/sec, G' and G" are each at least partly in the range of 10 ³ to 10 ⁷ Pa.

As explained above, particularly preferred gripping devices according to the invention comprise an optical detection unit with which the degree of curing can be determined during handling or irradiation with UV radiation in the case of curable adhesives in which the color properties depend on the degree of curing achieved. This enables particularly efficient process control and integrated quality control, in particular with automated and sensor-controlled process control. Accordingly, it is particularly preferred to use a corresponding curable adhesive. In addition, the inventors have succeeded in identifying particularly preferred embodiments for the curable adhesives to be used, with which in the process according to the invention using inventive Gripping devices can achieve excellent results. Firstly, a method according to the invention is preferred, wherein the curable adhesive mass comprises: x1) one or more (co)polymers, x2) one or more polymerizable epoxy compounds, and x3) one or more cationic initiators, and preferably x4) one or more pH color indicators with at least one pH-dependent color change.

A method according to the invention is preferred, wherein the curable adhesive is composed such that a pH-dependent color change of the one or more pH color indicators occurs during the cationic curing of the curable adhesive.

Additionally or alternatively, a process according to the invention is preferred, wherein the combined mass fraction of the (co)polymers in the curable adhesive is 25% or more, preferably 30% or more, particularly preferably 35% or more, based on the mass of the curable adhesive.

Additionally or alternatively, a process according to the invention is also preferred, wherein the one or more (co)polymers are selected from the group consisting of poly(meth)acrylates, polyurethanes, polyvinyl acetals, such as polyvinyl butyral, polysiloxanes, synthetic rubbers, polyesters, phenoxy polymers, polyvinyl alcohols, polyvinyl alcohol copolymers, and alkene-vinyl acetate copolymers, preferably selected from the group consisting of poly(meth)acrylates, phenoxy polymers, polyvinyl alcohols, polyvinyl alcohol copolymers, polyvinyl acetals, such as polyvinyl butyral, and ethylene-vinyl acetate copolymers (EVA or EVAC, poly(ethylene-co-vinyl acetate)), in particular selected from the group consisting of poly(meth)acrylates, phenoxy polymers and ethylene-vinyl acetate copolymers. Additionally or alternatively, a process according to the invention is also preferred, wherein the one or more polymerizable epoxy compounds are selected from the group consisting of epoxy compounds having at least one cycloaliphatic group, in particular a cyclohexyl group or dicyclopentadienyl group, and/or wherein the one or more polymerizable epoxy compounds are selected from the group consisting of bisphenol A diglycidyl ethers and bisphenol F diglycidyl ethers, preferably bisphenol A diglycidyl ethers.

Additionally or alternatively, a process according to the invention is also preferred, wherein the combined mass fraction of the polymerizable epoxy compounds in the curable adhesive is in the range from 35 to 95%, preferably in the range from 40 to 90%, particularly preferably in the range from 45 to 85%, very particularly preferably in the range from 50 to 80%, based on the mass of the curable adhesive.

For essentially all applications, a method according to the invention is preferred, wherein the one or more cationic initiators are selected from the group consisting of radiation-activated initiators. A method according to the invention is also particularly preferred, wherein the combined mass fraction of the cationic initiators in the curable adhesive is in the range from 0.1 to 7%, preferably in the range from 0.3 to 5%, particularly preferably in the range from 0.5 to 4%, based on the mass of the curable adhesive.

Finally, the use of a gripping device according to the invention in the handling of substrates bonded with curable adhesives while simultaneously curing the curable adhesives is also disclosed in order to increase the time and/or cost efficiency in the processing of battery cells.

Preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures. Fig. 1 is a schematic representation of a gripping device according to the invention in a preferred embodiment in a perspective view;

Fig. 2 is a schematic representation of parts of the gripping device according to the invention of Fig. 1 in a side view;

Fig. 3 is a schematic representation of parts of a gripping device according to the invention in an alternative preferred embodiment in a side view; and

Fig. 4 is a schematic representation of a gripping device according to the invention in use in a method according to the invention.

Fig. 1 shows a gripping device 10 according to the invention for handling substrates 12 bonded with curable adhesives while simultaneously curing the curable adhesives in a preferred embodiment. The gripping device 10 comprises a first gripping element 14, a second gripping element 16 and an electrically operated gripping mechanism 18 with a fastening device 24 arranged thereon for fastening the gripping device 10 to a robot arm. The gripping mechanism 18 connects the first gripping element 14 and the second gripping element 16 in such a way that a reversible and non-destructive opening and closing movement of the gripping elements relative to one another is made possible.

In the example shown, both the first gripping element 14 and the second gripping element 16 are designed as plate-shaped curing gripping elements which comprise a plurality of UV radiation sources 22 in a receiving recess 26 on one side of the rectangular base body 20, which together span a radiation area. The first gripping element 14 and the second gripping element 16 are designed in the same way, so that in particular the number of UV radiation sources 22 and the size of the radiation area do not differ.

Fig. 2 shows a plan view of one of the curing gripping elements of the gripping device 10. In this embodiment, the UV radiation sources 22 are in Fourteen parallel element rows each consisting of twenty-five UV radiation sources 22 are arranged so that each curing gripping element comprises a total of 364 UV radiation sources 22, which are evenly arranged in the receiving recess 26 and are covered by a transparent cover plate (not shown). In the example shown, the UV radiation sources 22 designed as UV LEDs have an emission maximum at a wavelength of approximately 365 nm.

The preferred curing gripping element of Fig. 2 also comprises a circumferential spacer element 28 surrounding the receiving recess 26, which is made of a rubber material and contacts the substrate when gripped.

Fig. 3 shows a further preferred embodiment of the curing gripping element, as it can be used in a preferred gripping device 10 according to the invention. In comparison to the embodiment of Fig. 2, this curing gripping element comprises an optical detection unit 30 designed as a camera, which is arranged centrally in the receiving recess 26 between the UV radiation sources 22. The optical detection unit 30 is designed to detect a change in the absorption behavior of the curable adhesive that occurs during the curing of the curable adhesive.

Fig. 4 shows the gripping device 10 according to the invention in use in a method according to the invention for handling substrates 12 bonded with curable adhesives while simultaneously curing the curable adhesives. In the example shown, the substrate 12 is designed as a prismatic energy cell, which is bonded on both sides with a curable adhesive in the form of a reactive adhesive film. In addition to an adhesive layer made of the curable adhesive, the adhesive film also comprises a carrier layer, which is expediently permeable to the UV radiation emitted by the UV radiation sources 22 of the gripping device 10.

The curable adhesive of the adhesive film is, for example, a UV radiation emitted by the UV radiation sources 22 of the gripping device 10 curable epoxy-based pressure-sensitive adhesive comprising a pH color indicator with at least one pH-dependent color change.

In the context of the method according to the invention, the gripping elements 14, 16 of the gripping device 10 grip the substrate 12 in such a way that a reversibly and non-destructively releasable force-fitting connection with the battery cell is formed by the first gripping element 14 and the second gripping element 16 being moved simultaneously and uniformly along a linear direction of movement by the gripping mechanism 18 in the manner of a parallel gripper.

The substrate 12 is then irradiated with suitable UV radiation using the UV radiation sources 22 of the first gripping element 14 and the second gripping element 16 in order to harden the curable adhesive on the surface of the prismatic energy cell. The irradiation takes place, for example, with a radiation dose of 8 J/cm ² for a time in the range of 10 s. The spacer element 28 and the recessing of the UV radiation sources 22 in the receiving recess 26 ensure a minimum distance of at least 0.5 mm between the surface of the adhesive film of the gripped prismatic energy cell and the UV radiation sources 22. The degree of curing is determined, for example, using the optical detection unit 30 of the gripping device 10 by optically detecting the pH-dependent color change of the pH color indicators in order to control the process depending on the registered color information, which allows information about the degree of curing already achieved.

The irradiation can, for example, take place during the movement of the gripping device 10 with the gripped substrate 12 from a starting position to a destination, so that the substrate 12 obtained after curing can be further processed directly at the destination in downstream processes after the substrate has been released from the gripping device 10 by dissolving the force-fitting connection.

List of reference symbols

10 Gripping device 12 Substrat

14 First gripping element

16 Second gripping element

18 Gripping mechanism 20 Base body

22 UV radiation source

24 Fastening device

26 Recording recess

28 Spacer element

30 Optical detection unit

Claims

Expectations

1. Gripping device (10) for handling substrates (12) bonded with curable adhesives while simultaneously curing the curable adhesives, comprising: i) a first gripping element (14), ii) a second gripping element (16), and iii) a gripping mechanism (18) connecting the first gripping element (14) and the second gripping element (16), wherein the gripping mechanism (18) is designed to move the first gripping element (14) and the second gripping element (16) reversibly and non-destructively relative to one another, wherein the gripping device (10) is designed to grip a substrate (12) between the first gripping element (14) and the second gripping element (16) and thereby to form a reversibly and non-destructively releasable, positive and/or force-fitting connection to the gripped substrate (12) by moving the first gripping element (14) and/or the second gripping element (16), wherein the first gripping element (14) and/or the second gripping element (16) is a curing gripping element, wherein the curing gripping element(s) comprise a base body (20) and a plurality of UV radiation sources (22) arranged on the base body (20) and designed to irradiate a substrate (12) gripped by the gripping device (10) with electromagnetic radiation, wherein the UV radiation sources (22) have the intensity maximum of the emission at a wavelength A in the range from 100 to 400 nm.

2. Gripping device (10) according to claim 1, wherein the gripping device (10) comprises a fastening device (24) for fastening the gripping device (10) to an automated movement device.

3. Gripping device (10) according to one of claims 1 or 2, wherein the gripping mechanism (18) is adapted to move the first gripping element (14) and/or the second gripping element (16) along a linear direction of movement or about a rotation axis.

4. Gripping device (10) according to one of claims 1 to 3, wherein the gripping device (10) is designed to form an at least partially non-positive connection to the gripped substrate (12).

5. Gripping device (10) according to one of claims 1 to 4, wherein the first gripping element (14) and/or the second gripping element (16) are plate-shaped.

6. Gripping device (10) according to one of claims 1 to 5, wherein the first gripping element (14) and the second gripping element (16) are curing gripping elements.

7. Gripping device (10) according to one of claims 1 to 6, wherein at least one curing gripping element (10) or more comprises UV radiation sources (22).

8. Gripping device (10) according to one of claims 1 to 7, wherein the UV radiation sources (22) are arranged in 2 or more element rows of 5 or more UV radiation sources (22), wherein the element rows are preferably arranged substantially parallel to one another.

9. Gripping device (10) according to one of claims 1 to 8, wherein at least one curing gripping element on the surface of the base body (20) facing in the direction of the substrate (12) to be irradiated comprises at least one receiving recess (26) in the base body (20), wherein the UV radiation sources (22) are at least partially arranged in the receiving recess (26).

10. Gripping device (10) according to one of claims 1 to 9, wherein at least one curing gripping element on the surface of the base body (20) facing in the direction of the substrate (12) to be irradiated comprises a spacer element (28), wherein the spacer element (28) is designed to ensure a minimum distance between the surface of the base body (20) facing in the direction of the substrate (12) to be irradiated and the substrate (12).

11. Gripping device (10) according to one of claims 1 to 10, wherein at least one curing gripping element comprises at least one optical detection unit (30) which is designed to detect a change in the absorption behavior of the curable adhesive mass occurring during the curing of the curable adhesive mass.

12. Gripping device (10) according to one of claims 1 to 11, wherein the UV radiation sources (22) have the intensity maximum of the emission at a wavelength A in the range of 200 to 390 nm.

13. Method for handling substrates (12) bonded with curable adhesives while simultaneously curing the curable adhesives with a gripping device (10) according to one of claims 1 to 12, comprising the method steps: a) producing or providing a substrate (12) bonded with a curable adhesive, b) gripping the bonded substrate (12) between the first gripping element (14) and the second gripping element (16) of the gripping device (10) to form a reversibly and non-destructively detachable, positive and/or non-positive connection to the gripped substrate (12), c) irradiating the substrate (12) gripped by the gripping device (10) with UV radiation from the UV radiation sources (22) of the curing gripping elements emitted electromagnetic radiation of a wavelength A in the range from 100 to 400 nm for curing the curable adhesive masses and for obtaining a substrate (12) with cured adhesive mass, and d) dissolving the reversibly and non-destructively detachable, positive and/or non-positive connection between the gripping device (10) and the substrate (12) with cured adhesive mass.

14. The method of claim 13, wherein the substrate (12) is a battery cell.

15. The method according to claim 13 or 14, wherein the irradiation is carried out with a radiation dose in the range of 1 to 12 J/cm ² .