Method for connecting a first component to a second component using an interface material, interface material and battery

Abstract

The invention relates to a method for joining a first component (10) to a second component (12) by means of a viscous and curable interface material (14, 14a, 14b), wherein the first and second components (10, 12) and the interface material (14, 14a, 14b) are arranged relative to each other such that the interface material (14, 14a, 14b) is located between the first and second components (10, 12), and wherein the interface material (14, 14a, 14b) comprises a first component (22, 22a) in the form of a mass (22a) and a second component (24, 24a, 24b).This is provided in the form of microbodies (24a, 24b) distributed in the viscous mass (22a), each comprising an outer shell (26) enclosing an interior space (28) and an activator substance (30) contained in the interior space (28), which, upon contact with the first component (22, 22a), triggers or accelerates a crosslinking reaction, wherein, after arrangement, the outer shells (26) of at least some of the microbodies (24a, 24b) are damaged to release the activator substance (30).

Description

[0001] The invention relates to a method for bonding a first component to a second component using a viscous and curable interface material. While the interface material is in a viscous state, the first component, the second component, and the interface material are arranged relative to one another such that the interface material is located between the first and second components. The interface material, in the viscous state, comprises a first component in the form of a viscous, curable mass and a second component mixed with the mass. Furthermore, the invention also relates to an interface material and a battery.

[0002] Interface materials are used to bond components together, particularly for thermal and / or mechanical bonding. Examples include structural adhesives and thermally conductive fillers. Such interface materials are frequently used in body construction and battery assembly between a battery module and, for example, a battery cover or a battery tray. In body construction, structural adhesives are cured using thermal processes, e.g., using an oven, such as a KTL (cathodic dip painting) oven, and are often combined with additional manufacturing processes that prevent the components from shifting until the adhesive cures in the oven.In battery production, thermally conductive fillers, so-called thermal interface materials (TIM), are often used. These transfer the heat generated during load operation of the battery modules or the heat generated during rapid charging to the corresponding cooling elements, cooling plates, or other cooling devices. This is intended to prevent overheating of the cells, regulated by the battery management system. Thermal interface material fillers are often used as 2K (component) fillers, i.e., they comprise two miscible components that initiate the curing process when mixed. Such 2K fillers generally cure at room temperature. The required curing time is determined by the chemical composition of the thermal interface materials.In addition to the task of heat conduction, some thermal interface material fillers should also be able to transfer strength, which is where thermally conductive adhesives come into play. Curing of the thermally conductive adhesive, which can transfer strength, is not possible in the battery module, as is the case in car body construction, using an oven. Until now, interface materials have been cured in two ways: by curing with a defined and particularly long curing time at room temperature, or by curing with additional external heat sources via the coupling of heat through cooling elements or housing or the battery tray and conduction into the interface material. This allows for shorter curing times. However, this requires a high investment in equipment, i.e.high system costs and a complex design of such systems, as well as high heat losses due to the large thermal mass of the battery modules, inhomogeneous heat distribution due to geometry and component material tolerances, and high heat dissipation into the battery module.

[0003] It would therefore be desirable to show a possibility how the curing process of such an interface material can, on the one hand, take place as quickly as possible, but on the other hand, the initiation of the curing process can be controlled as precisely as possible and can be designed as simply as possible.

[0004] DE 10 2019 209 863 A1 describes a battery device with a battery module comprising a plurality of battery cells and with a cooling plate battery module that at least partially delimits a cavity.

[0005] This is filled with a thermally conductive material, which is introduced into the cavity via an inlet channel. The thermally conductive material can be an oil with a gelling agent, which gels the oil introduced into the cavity. The oil can be introduced in liquid form through the inlet channel and subsequently gels.

[0006] WO 2022 / 129299 A1 describes a thermally conductive adhesive with low density and high electrical resistance. This adhesive comprises several components, such as a moisture-curable prepolymer, a thermally conductive filler, e.g., graphene, optionally another thermally conductive nanofiller, and a thermally conductive macrofiller. The adhesive can optionally also comprise a curing catalyst.

[0007] With interface materials where the curing process is already triggered or begins before the components to be joined via the interface material are properly aligned, there is a risk that, for example, in the event of delays in the assembly process, excessively rapid curing will result in the components to be joined no longer being able to be joined. However, if interface materials are designed to have a sufficiently long open time - the time span from the onset of the curing process within which components can be joined via the interface material - sufficient time is provided to properly join the components to be joined via this interface material before the interface material has cured too much.However, this means that the curing process as a whole takes a very long time and the so-called handling strength, from which further, subsequent production steps can be carried out without additional aids or fastenings, is only achieved after a long time.

[0008] The object of the present invention is therefore to provide a method, an interface material and a battery which, on the one hand, enable the curing process of an interface material to proceed as quickly as possible and, on the other hand, provide sufficient time to arrange the components to be joined via the interface material in accordance with their intended purpose, without the interface material curing too prematurely.

[0009] This object is achieved by a method, an interface material, and a battery having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0010] In a method according to the invention for bonding a first component to a second component using a viscous and curable interface material, the first component, the second component, and the interface material are arranged relative to one another while the interface material is in a viscous state such that the interface material is located between the first component and the second component. In the viscous state, the interface material comprises a first component in the form of a viscous, curable mass and a second component mixed with the mass. Furthermore, the second component of the interface material is provided in the form of micro-bodies distributed throughout the viscous mass, each comprising an outer shell enclosing a respective interior space containing an activator substance that triggers or accelerates a crosslinking reaction upon contact with the first component.Furthermore, after arranging the first component, the second component and the interface material to each other, the outer shells of at least some of the microbodies are damaged to release the activator substance.

[0011] This advantageously allows the activator substance to be integrated into the interface material without immediately initiating or accelerating the crosslinking reaction that leads to the curing of the interface material. Because this activator substance is absorbed into the outer shells of the microbodies, it is advantageously possible to release the activator substance in a targeted manner at a desired time, e.g. by deliberately damaging the outer shells of the microbodies. This advantageously means that the time at which the curing process is to be initiated or accelerated can in principle be freely selected and, in the present case, is selected such that the curing process is only initiated or accelerated when the components and the interface material are already arranged relative to one another, and accordingly the interface material is already arranged between the first component and the second component, in particular contacting these two components.Thus, the curing process can advantageously be initiated or accelerated specifically when the joining partners to be joined via the interface material, namely the first and second components, are already arranged and coupled to each other via the interface material as intended. This eliminates the risk of premature curing of the interface material. Furthermore, with this approach, the curing or crosslinking process, which is triggered or accelerated by the contact of the activator substance with the viscous mass of the interface material, can be designed in such a way that a specific strength of the interface material, e.g., the handling strength mentioned above, can be achieved within an extremely short period of time.This allows subsequent assembly steps of the assembled components to be completed quickly, without the need for additional, laborious fixing tools. This saves material costs and, above all, production time.

[0012] The handling strength can be defined, for example, as a predetermined strength, e.g. shear strength and / or tensile strength and / or compressive strength and / or bending strength and / or torsional strength and / or breaking strength, between the two components, e.g. depending on the application. The limit value above which the handling strength is reached can, for example, be at or in the order of magnitude of 0.25 MPa. Depending on the application, the handling strength can also be defined differently or as a different limit value for at least one of the strengths mentioned above. The handling strength is, however, reached before the interface material has fully cured. In other words, the fully cured interface material still has at least a slightly higher strength than at the time at which it reaches the predetermined handling strength.

[0013] A microbody is understood to be a particularly small body, although this body does not necessarily have to have dimensions in the micrometer range. Such a microbody can, for example, also have dimensions, e.g., a maximum outer diameter, in the range of millimeters. However, the outer diameter is preferably only a few millimeters, e.g., less than 5 millimeters or less than 3 millimeters, e.g., less than 2 millimeters, and in particular, a maximum of 1 millimeter.

[0014] The rate of the crosslinking reaction triggered upon contact between the activator substance and the first component can be influenced by the composition of the activator substance and / or the first component, and would therefore be suitable, as well as additionally or alternatively by the amount of activator substance compared to the amount of the first component. The higher the microbody concentration with the incorporated activator substance within the interface material, the faster the crosslinking reaction triggered upon contact can proceed.

[0015] The outer shells of the microbodies can be rigid or flexible and / or elastically deformable. In principle, the outer shells can be made of any material. For example, the outer shells can be made of a plastic. Damage to the outer shell, as occurs after the first component, second component, and interface material have been arranged relative to one another, at least for some of the microbodies, leads to at least partial opening of the outer shells, so that the activator substance contained therein can escape from the interior of the respective microbody. Since the microbodies are distributed throughout the viscous mass, contact between the activator substance and the first component of the interface material occurs when the outer shells are opened, which triggers or accelerates the crosslinking reaction.

[0016] The activator substance can be tailored to the first component of the interface material in terms of its composition. Accordingly, the activator substance is designed such that it accelerates or triggers the crosslinking reaction upon contact with the first component, in particular the viscous mass of the interface material.

[0017] The activator substance and the viscous mass can be designed in such a way that no crosslinking reaction occurs without contact between the viscous mass and the activator substance, and the viscous mass thus remains in its viscous state without contact with the activator substance. Only upon contact with the activator substance does the crosslinking reaction occur. The resulting increasing crosslinking of the viscous mass leads to a gradual hardening of the viscous mass until it finally transitions to a solid state.

[0018] The viscous mass and the activator substance can also be designed in such a way that the viscous mass gradually crosslinks or hardens without contact with the activator substance. In this case, crosslinking or hardening of the viscous mass already takes place before contact with the activator substance. However, this crosslinking reaction is accelerated, in particular significantly accelerated, upon contact with the activator substance. This means that the crosslinking reaction proceeds significantly faster after contact with the activator substance than before contact with the activator substance. This also makes it possible to reliably join the components to be joined via the interface material, since the very slow crosslinking process of the viscous mass without contact with the activator substance provides sufficient time to arrange the first and second components and the interface material as intended.The subsequent acceleration of the crosslinking reaction through the contact of the viscous mass with the activator substance emanating from the damaged outer shells can also advantageously achieve accelerated curing of the interface material to the desired strength within a very short time.

[0019] When the interface material is in a viscous state, it is flowable. In this state, the interface material can be liquid or pasty, depending on the composition of the viscous mass.

[0020] As explained in more detail later, the first component is preferably a battery unit. The battery unit can be a cell stack with a plurality of battery cells or a cell group with a plurality of battery cells or even a battery module with such a cell stack or such a cell group. Such a battery module can optionally also have a module housing in which the plurality of cells are accommodated. The component to which the battery unit is connected can itself, however, also be part of such a module housing, e.g. represent a module cover or module base. However, it can also be different from a module housing and, for example, be part of an overall battery housing in which, in addition to the battery unit, further such battery units, in particular battery modules, are accommodated.For example, the component can also represent a cooling base of such an overall battery housing or a cooling lid of such an overall battery housing, or even an intermediate wall or side wall of such a housing. In principle, it is preferred that the component is a cooling device for cooling the battery unit or several cooling battery units. It is therefore advantageous if the interface material also has good, thermally conductive properties. The interface material can then, for example, be designed as a thermal interface material. For this purpose, the first component of the interface material can, for example, comprise thermally conductive particles and a matrix in which these thermally conductive particles are accommodated. This matrix with the thermally conductive particles accommodated therein can form the first component of the interface material.In principle, however, the described procedure can also be applied to other interface materials that do not necessarily have to have thermally conductive properties, e.g. adhesives to create structural connections between two components.

[0021] In principle, the described process can be used to join any two components using an interface material. The interface material can generally only perform gap-filling and / or fastening functions. To provide fastening functions, the interface material can exhibit adhesive and thus structurally bonding properties and, for example, be designed as an adhesive. As a gap filler, the interface material does not necessarily have to also exhibit structurally bonding properties. In both cases, the interface material can optionally also exhibit thermally conductive properties. In this case, it can also be referred to as a thermal interface material (TIM).

[0022] In an advantageous embodiment of the invention, the outer shells of at least some of the microbodies are damaged by exerting pressure on the microbodies, in particular, damaged in such a way that they tear and / or burst and / or break. By exerting pressure, damage to the outer shells of the microbodies can be caused in a particularly simple and efficient manner. This consequently enables particularly simple activation of the microbodies.

[0023] Such pressure can be easily applied by providing a suitable compressive force. This provided compressive force does not have to act directly on the outer shells, but can in principle also act at any other location, while the compressive force is transferred to the outer shells of the microbodies, for example via the viscous mass. This compressive force also does not have to act directly on the interface material, but can also act on one of the components. This advantageously means that access to the interface material located in the gap between the two components is not required. This is also particularly advantageous because it allows the process of damaging the outer shells to be easily integrated into the assembly process for arranging the two components relative to one another.

[0024] Accordingly, it represents a further advantageous embodiment of the invention if, after the first and second components and the thermal interface material have been arranged relative to one another, the first component and the second component are pressed against one another in order to exert pressure on the micro-bodies. In the course of this, for example, the second component can be fixed in terms of its position, e.g. be located on a support or the like, and the first component can be arranged on the second component via the interface material by being placed on the second component and pressed in the direction of the second component. The same is also possible in reverse, ie the first component can be fixed in terms of its position, and the second component can be arranged on the first component via the interface material and pressed against it. The two components can also both be pressed against one another.In order to move the components or at least one of them and to position and press them relative to the other, a suitable gripping and handling device and / or a press can be used.

[0025] Applying pressure also allows the still-viscous interface material between the two components to spread. The gap, or rather the gap height between the two components, which is filled with the interface material or is filled during the pressing process, is thus minimized. In the final state, i.e., after pressing, the gap height is a maximum of a few millimeters and ranges, for example, between 0.8 mm and 3.0 mm, especially less than 3.0 mm. The gap height can also vary slightly in certain areas.

[0026] The dimensions of the micro-bodies can, for example, be on the order of magnitude of the gap height and, for example, amount to a few millimeters, in particular less than 3.00 mm, preferably less than 2.0 or 1.00 mm. The outer shells of the micro-bodies can, for example, be caused to burst or open if, when the two components are pressed together, such a micro-body comes into contact with both sides of both components simultaneously and is pressed together by these until the outer shell is damaged. A micro-body can, for example, contact both the first and the second component and be damaged accordingly by the contact force. It is also conceivable, however, that the micro-bodies have dimensions that are smaller than this gap height and, when the components are pressed together, at least partially come into direct contact with at most only one of the two components, if at all.The pressure exerted by the components on the interface material in between is also transferred to the microbodies in the viscous mass, which can compress and damage them in order to release the absorbed activator substance.

[0027] In general, it is therefore very advantageous if, after arranging the first component, the second component, and the interface material relative to one another, the first component and the second component are pressed together to release the activator substance from the outer shells of at least some of the microbodies and to trigger or accelerate the crosslinking reaction. This advantageously allows the activation of the crosslinking reaction or the acceleration of the crosslinking reaction of the interface material to be integrated into the assembly and arrangement process of the two components in a particularly efficient and simple manner. In particular, no additional assembly or handling steps are then required to activate or release the activator substance.The components can be easily arranged and pressed together via the interface material, which then automatically releases the activator substance by damaging the outer shell of at least some of the microbodies.

[0028] In a further advantageous embodiment of the invention, the interface material is an adhesive, in particular a thermally conductive adhesive. This embodiment is particularly advantageous because, for example, such adhesives, in particular thermally conductive adhesives, are distinguished from non-adhesive interface materials, such as the gap fillers mentioned at the outset, in that they additionally have adhesive properties and, after curing, can also transmit forces between the components joined together via the interface material. This means that these two components do not necessarily have to be fastened to one another using additional fastening means, such as screws or the like. The use of an adhesive, in particular a thermally conductive adhesive, therefore has the advantage that additional fastening means can be dispensed with.However, especially when the two components are not stabilized against each other by additional fastening means after being arranged via the interface material, it is very advantageous if the interface material cures very quickly. This allows the handling strength described above to be achieved particularly quickly, and subsequent assembly or production steps can be carried out without the need for additional stabilization and fastening measures. The precisely controllable onset of the accelerated curing or hardening of the interface material and the ability to carry out the curing process very quickly are particularly advantageous when the interface material is an adhesive, in particular a thermally conductive adhesive.

[0029] According to a further advantageous embodiment of the invention, the microbodies are designed as microspheres, in particular with a diameter of a maximum of 2 millimeters, preferably a maximum of 1 millimeter, and particularly preferably less than 1 millimeter. The sphere design has the advantage of being particularly easy to manufacture. In principle, however, the microbodies can also be bulky bodies, e.g., with soft, flexible outer shells. The geometric shape of the microbodies can also be alterable if the outer shell is flexible or deformable.

[0030] In a further advantageous embodiment of the invention, the first component represents a battery unit, which in particular comprises a cell stack with a plurality of battery cells, and the second component represents a cooling device, in particular a cooling cover or cooling base as a housing for the battery unit. The described method offers particularly great advantages when connecting the battery unit and the cooling device. It is also preferred that the interface material also has thermally conductive properties. This enables a thermal connection of the battery unit and a cooling device via the thermal interface material. In addition, this connection process can be carried out extremely efficiently, precisely timed, and in a targeted manner. Especially when a thermally conductive adhesive is used as the thermal interface material, a structural connection between the battery unit and the cooling device can be ensured.The described method and its embodiments can be part of a manufacturing method for producing a high-voltage battery. In the course of such a manufacturing method, a plurality of battery modules can be accommodated in an overall battery housing. Each battery module can comprise such a battery unit. Optionally, a battery module can also comprise a module housing. Such a module housing can have a module frame and optionally a module housing base and / or module housing cover. The cooling device can be designed as a cooling cover or cooling base, e.g. of the overall battery housing for the plurality of battery units and / or as a cooling cover and / or cooling base of a module housing. However, the cooling device can also be designed as another housing wall of such a housing, e.g. as a side wall or partition wall of an overall battery housing or module housing.In addition, the cooling device can be designed as an active cooling device or a passive cooling device, i.e. it can be designed so that a coolant can flow through it or not.

[0031] Accordingly, a further advantageous embodiment of the invention is provided if the cooling device has cooling channels through which a coolant can flow. This enables particularly efficient cooling of the battery unit. In this case, a thermal connection between the battery unit and the cooling device via the interface material is particularly advantageous. Alternatively, the cooling device can also be designed as a solid cooling plate or a solid cooling sheet. This cooling plate or cooling sheet can in turn be connected to an active cooling unit, which in turn has cooling channels through which a coolant can flow. This makes it possible, for example, to arrange the cooling plate or cooling sheet to the side of the battery unit, e.g. as the side wall of a module housing and / or battery housing.In principle, a plurality of components designed as respective cooling devices can also be connected to the battery unit according to the described method, in particular using a respective interface material located therebetween. In this way, for example, multi-sided cooling can be provided for the battery unit. In particular, both a cooling cover and a cooling base can be connected on both sides of two opposite sides of the battery unit via a respective interface material and / or further cooling devices, e.g. designed as cooling plates or cooling sheets, can be connected via a respective interface material to display surfaces of the battery unit that are different from a top and bottom of the battery unit to which the cooling cover and / or the cooling base are connected. In principle, such an interface material can also be used anywhere else.For example, such a cooling device can also be designed as an inter-cell cooling device, which is arranged in a cell stack of several battery cells between two cells adjacent to each other in the stacking direction. Other battery components that are to be connected to a cooling system, e.g., module connectors or the like, can also be connected to the cooling system using a suitable interface material according to the described method. In principle, the first component can also be another battery component of a battery, e.g., a high-voltage battery, or any other motor vehicle component.

[0032] Furthermore, the invention also relates to an interface material for connecting at least a first component to a second component, wherein the interface material has a viscous state and, in the viscous state, comprises a first component in the form of a viscous, curable mass, and a second component mixed with the mass. In the viscous state of the interface material, the second component is provided in the form of microbodies distributed throughout the viscous mass, each comprising an outer shell enclosing a respective interior space in which an active substance is accommodated, which is designed to trigger or accelerate a crosslinking reaction upon contact with the first component.

[0033] The advantages described for the method according to the invention or its embodiments apply equally to the interface material according to the invention.

[0034] According to a further advantageous embodiment of the invention, the interface material, in particular the microbodies, is designed such that the outer shells of at least some of the microbodies can be damaged by exerting pressure on the interface material in such a way that the activator substance accommodated in their interior escapes from the damaged outer shells.

[0035] The activator substance can generally be in liquid form, in solid form, e.g. in the form of a powder, or possibly also in gaseous form.

[0036] Furthermore, the invention also relates to a battery for a motor vehicle with an interface material according to the invention or one of its embodiments.

[0037] The battery can comprise a first and a second component, which are connected to one another via the interface material. The first and second components can be configured as described, for example, in connection with the method according to the invention and / or its embodiments. The first component can thus be, for example, a battery unit, and the second component can be provided, for example, as a housing component and / or cooling device. The interface material can also be configured as already described in connection with the method according to the invention and its embodiments.

[0038] In general, the invention also relates to a battery for a motor vehicle which has been produced by means of a method according to the invention or one of its embodiments.

[0039] The battery can be a high-voltage battery, for example. The battery cells can be lithium-ion cells, for example.

[0040] A motor vehicle with an interface material according to the invention or one of its embodiments and / or a battery according to the invention or one of its embodiments shall also be considered to be part of the invention.

[0041] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0042] The invention also includes further developments of the interface material according to the invention and the battery according to the invention that have features already described in connection with the further developments of the method according to the invention. For this reason, the corresponding further developments of the interface material according to the invention and the battery according to the invention are not described again here.

[0043] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0044] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a schematic representation of a method step for joining two components via an interface material according to an embodiment of the invention; Fig. 2 a schematic representation of a further method step for joining two components via an interface material according to an embodiment of the invention; and Fig. 3 a graphical representation of the curing process of an interface material as a function of time according to an embodiment of the invention.

[0045] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0046] In the figures, the same reference symbols designate elements with the same function.

[0047] Fig. 1 shows a schematic representation of a first method step S1 in a method for connecting a first component 10 to a second component 12 by means of a viscous and curable interface material 14 according to an exemplary embodiment of the invention. In this example, the first component 10 represents a battery module 10a, which may, for example, comprise a plurality of battery cells 10b, of which only one is shown by way of example. The second component 12 in this example represents a cooling device 12a, in particular in the form of a module cover 12b with liquid cooling. Corresponding cooling channels 16, through which a cooling medium can flow, are integrated into the module cover 12b. The cooling device 12a serves to cool the battery module 10a.In order to thermally connect this cooling device 12a to the battery module 10a as effectively as possible and to avoid any type of air inclusions when arranging the cooling device 12a on the battery module 10a, the interface material 14 is placed between the cooling device 12a and the battery module 10a. For this purpose, the interface material 14, which in this example is preferably embodied as a thermal interface material 14a, in particular as a thermally conductive adhesive 14b, can first be arranged on a corresponding contact side 18 of the second component 12, which faces the first component 10 when the first and second components 10, 12 are arranged relative to one another as intended. Additionally or alternatively, the interface material 14 can also be arranged on a second contact side 20 of the second component 10, which faces the second component 12 when the first and second components 10, 12 are arranged relative to one another as intended.

[0048] In this example, the interface material 14 is arranged on the first contact side 18 of the second component 12. Fig. Figure 1 shows the state of the components 12, 10 in which they are not yet arranged next to one another. The interface material 14, in particular the thermally conductive adhesive 14b, can thus first be applied to the contact side 18 of the cooling device 12a. Subsequently, the second component 12 is arranged on the first component 10 such that the interface material is located between the two components 10, 12. During this arrangement, the interface material is in a viscous state Z1.

[0049] Through a special design of the interface material 14, it is now possible to design the curing process of this interface material 14 very advantageously. For this purpose, the interface material 14 has two components, namely a first component 22, which is provided as a viscous mass 22a in the viscous state Z1 of the interface material 14, and a second component 24, which is provided in the form of several microbodies 24a. These are distributed throughout the first component 22. In particular, these microbodies 24a can be in the form of microspheres 24b. Each microbody 24a is designed as follows: It has an outer shell 26, which, in an undamaged state, completely surrounds and encloses an interior space 28. An activator substance 30 is also arranged in the interior space 28. This activator substance can fill the interior space 28 completely or only partially.This activator substance 30 is designed such that, upon contact with the first component 22, it triggers or significantly accelerates the curing or crosslinking process. These microbodies 24a are very small and can have dimensions in the millimeter or even micrometer range. In the embodiment shown in . Fig. In the example shown in Figure 1, the thermally conductive adhesive 14b comprises the activator microspheres 24b or, in general, the microbodies 24a in a not yet activated state and the thermally conductive adhesive 14b is in a still soft, ie viscous, state Z1.

[0050] Fig. 2 shows a schematic representation of a further step S2, which is carried out after the Fig. 1 is carried out. In this case, the first component 10 is now arranged relative to the second component 12 such that the interface material 14 is located between the two components 10, 12 and completely fills the intermediate space 32 in this mutually arranged state of the first and second components 10, 12. In this arranged state, a pressing force K, which is illustrated by the arrows K, e.g. by means of a press 38, is then exerted on the first component 10 in order to press it against the second component 12. It would also be conceivable to press the second component 12 against the first component 10 with a corresponding pressing force K. The two components 10, 12 can also be pressed against one another by respective, oppositely directed pressing forces. This pressing force K leads to a corresponding exertion of pressure on the interface material 14 and accordingly on the micro-bodies 24a.This causes damage to the respective outer shells 26 of at least some of the microbodies 24a and the activator substance 30 accommodated in the interior 28 to escape. In other words, this pressing force K crushes the microbodies 24a and the activator substance 30 escapes from them and comes into contact with the first component 22. This initiates or accelerates the cross-linking process.

[0051] In the Fig. In the example shown in Figure 2, the microspheres 24b enclosed by the interface material 14, namely the thermally conductive adhesive 14b, are already crushed, i.e., the microspheres 24b are in a state B with a damaged outer shell 26, in which the activator substance 30 has already at least partially extruded from the spheres 24b. Activation has thus begun, and the adhesive 14b becomes solid. Thus, in general, the interface material 14 transitions into a second state Z2, e.g., a solid state, or at least into a state Z2 with greater strength than in the first state Z1.

[0052] This provides a battery arrangement 34 which may, for example, be part of a high-voltage battery 36 or may be designed as such.

[0053] The described procedure can also be carried out analogously with any other first and second components 10, 12.

[0054] Fig. Figure 3 shows a graphical representation of the curing process of an interface material 14 according to an embodiment of the invention as a function of time t, particularly in comparison to the curing process of a conventional two-component interface material. The curing process of the interface material 14 is illustrated by curve K1, which particularly describes the strength F over time t, and the corresponding curve for a conventional two-component interface material is designated K2.

[0055] In an initial state of the interface material 14, in which the microspheres 24b are still intact, a slight increase in strength occurs during the time period Δt1, but this increase is such that within this time period Δt1 a joining of the two joining partners, namely the first component 10 and the second component 12, via the interface material 14 is still possible without any problems. Within the time period Δt1, for example, the Fig. 1 described first method step S1 is executed. At time t1, for example, the Fig.2 is carried out. In this step, the two components 10, 12 are pressed against each other, whereby the microspheres 24b are damaged and the activator substance 30 escapes. The damage to the microspheres 24b and / or the application of the corresponding contact force K to damage these microspheres 24b takes place, for example, at time t1 or begins at time t1. As can be seen in curve K1, this significantly accelerates the crosslinking process of the interface material 14. Thus, a defined handling strength FH can advantageously be achieved within a very short time. The handling strength can be defined as desired depending on the requirements, in such a way that the subsequent execution of further process and handling steps with the provided component arrangement, e.g.of the battery assembly 34, without running the risk of the two components 10, 12 shifting relative to each other and / or the interface material layer 14 cracking or otherwise being damaged. This handling strength FH can, for example, differ from a final target strength FZ that the interface material 14 assumes when it is fully cured, which in this case is the case at time t3.

[0056] In this example, the time t2 at which the interface material 14 reaches the specified strength, namely the handling strength FH, lies within the second time interval Δt2, which can be in the single-digit minute range, for example, or as short as two minutes. The handling strength can also be defined such that the time t2 also lies at the end of this time interval Δt2. However, it takes several days, e.g., eight days, to reach the target strength FZ.

[0057] As the comparison with curve K2 of a conventional interface material shows, the handling strength FH can be achieved significantly more quickly using an interface material 14 according to the invention or one of its embodiments. Furthermore, the invention still makes it possible to provide a sufficiently long period of time Δt1 for arranging the components 10, 12 relative to one another. Production delays or similar factors that result in the arranging of the two components 10, 12 relative to one another taking longer do not have a detrimental effect. The activation of the crosslinking process or the acceleration of the crosslinking process, and in particular the time t1 at which this crosslinking process is to be initiated or accelerated, can be controlled and thus determined by process engineering.In particular, this time t1 is always automatically after the two components have been arranged relative to each other due to the process, since the activation occurs by pressing the two components together in the already arranged state.

[0058] Overall, the examples show how the invention can provide a method for activating, in particular gelling or curing, thermal interface material (TIM), i.e. a thermal interface material, by applying pressure to microspheres containing activator. The underlying idea, according to one embodiment, comprises the implementation of microspheres into the thermally conductive adhesive filler and thus into the starting material to be applied. The microspheres contain, for example, a chemical activator that causes the thermally conductive adhesive to cure, at least to a handling strength. Curing is activated by exerting mechanical pressure on the microspheres, which leads to a release of the catalysts provided by the activator and thus initiating the chemical reaction.The pressure required to burst the microspheres is generated during the module assembly manufacturing process by pressing the cell pack with the thermally conductive adhesive against a module cover or module base, with or without an integrated cooling function. The pressing process of the battery cells with the thermally conductive adhesive and the module cover or module base is preferably a production step that is already performed, but is now additionally used to activate the adhesive by crushing the microspheres. This has the advantage of accelerated curing of the thermally conductive adhesive, at least to the point of handling strength, up to complete curing, depending on the design and requirements. This saves space and investment costs for additional curing mechanisms and prevents the complex process of curing by applying heat. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 209 863 A1

[0004] WO 2022 / 129299 A1

[0006]

Claims

[1] Method for bonding a first component (10) to a second component (12) by means of a viscous and curable interface material (14, 14a, 14b), - wherein, while the interface material (14, 14a, 14b) is in a viscous state (Z1), the first component (10), the second component (12) and the interface material (14, 14a, 14b) are arranged relative to one another in such a way that the interface material (14, 14a, 14b) is located between the first component (10) and the second component (12), and - wherein the interface material (14, 14a, 14b) in the viscous state (Z1) comprises a first component (22, 22a) in the form of a viscous, curable mass (22a) and a second component (24, 24a, 24b) mixed with the mass (22a), characterized by , that - the second component (24, 24a, 24b) is provided in the form of micro-bodies (24a, 24b) distributed in the viscous mass (22a), each comprising an outer shell (26) enclosing a respective interior space (28) in which an activator substance (30) is accommodated, which triggers or accelerates a cross-linking reaction upon contact with the first component (22, 22a), - after arranging the first component (10), the second component (12) and the interface material (14, 14a, 14b) relative to one another, the outer shells (26) of at least some of the microbodies (24a, 24b) are damaged to release the activator substance (30). [2] Method according to claim 1, characterized by that the outer shells (26) of at least some of the microbodies (24a, 24b) are damaged, in particular tearing and / or bursting and / or breaking, by exerting pressure on the microbodies (24a, 24b). [3] Method according to one of the preceding claims, characterized bythat after arrangement, the first component (10) and the second component (12) are pressed against each other relative to exert pressure on the micro-bodies (24a, 24b). [4] Method according to one of the preceding claims, characterized by that the interface material (14, 14a, 14b) is a thermally conductive adhesive (14b). [5] Method according to one of the preceding claims, characterized by that the microbodies (24a, 24b) are designed as microspheres (24b), in particular with a diameter which is at most 2 mm, preferably at most 1 mm, particularly preferably less than 1 mm. [6] Method according to one of the preceding claims, characterized byin that the first component (10) represents a battery unit (10a), which in particular comprises a cell stack with a plurality of battery cells (10b), and the second component (12) represents a cooling device (12a), in particular a cooling cover (12b) or cooling base of a housing for the battery unit (10a). [7] Method according to one of the preceding claims, characterized by that the cooling device (12a) has cooling channels (16) through which a coolant can flow or is designed as a solid cooling plate or a solid cooling sheet. [8] Interface material (14, 14a, 14b) for connecting at least one first component (10) to a second component (12), - wherein the interface material (14, 14a, 14b) has a viscous state (Z1) and in the viscous state (Z1) comprises a first component (22, 22a) in the form of a viscous, curable mass (22a), and a second component (24, 24a, 24b) mixed with the mass (22a), characterized by , that - the second component (24, 24a, 24b) is provided in the viscous state (Z1) of the interface material (14, 14a, 14b) in the form of microbodies (24a, 24b) distributed in the viscous mass (22a), each comprising an outer shell (26) enclosing a respective interior space (28) in which an activator substance (30) is accommodated, which is designed such that it triggers or accelerates a crosslinking reaction upon contact with the first component (22, 22a). [9] Interface material (14, 14a, 14b) according to claim 8, characterized by that the interface material (14, 14a, 14b), in particular the microbodies (24a, 24b), is designed such that the outer shells (26) of at least some of the microbodies (24a, 24b) can be damaged by exerting pressure on the interface material (14, 14a, 14b) in such a way that the activator substance (30) accommodated in their interior (28) escapes from the damaged outer shells (26). [10] Battery (34, 36) for a motor vehicle with an interface material (14, 14a, 14b) according to one of claims 8 or 9.

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