Method and system for producing a thermal interface in a battery for a motor vehicle

Abstract

Method for producing a thermal interface in a battery (10) for a motor vehicle, comprising the steps: - Providing at least one battery module (12) and at least one receiving structure (40) with a receiving area (46) having a heat transfer surface (14) for receiving one side (16) of the battery module (12) in an intended installation position; - Measuring the recording area (46) and / or the side of the battery module (12) using a measuring device (48); - Determining the size and shape of a gap that results in the intended installation position of the battery module (12) between the heat transfer surface (14) and the side (16) of the battery module (12) by means of a data processing device (50) based on the measurement; - Determining a dosage specification for a thermal conductivity material (18) to fill the gap based on the determined size and shape of the gap using the data processing device (50); - Applying the thermal conductivity material (18) to the heat transfer surface (14) and / or the side (16) of the battery module (12) according to the determined dosage specification using a dosing device (52); - Mounting the battery module (12) in the intended installation position by pressing the applied thermal conductivity material (18) using a mounting device (54), whereby the pressed thermal conductivity material (18) forms the thermal interface between the side (16) of the battery module (12) and the heat transfer surface (14), taking into account local differences regarding stiffnesses of the receiving structure (40) and / or the battery module (12) when determining the dosage specification.

Description

Technical area

[0001] The present invention relates to a method and a system for producing a thermal interface in a battery for a motor vehicle. State of the art

[0002] In automotive battery systems, so-called thermal interface materials or gap fillers, or more generally, thermally conductive materials, are typically used to dissipate heat and compensate for tolerances in existing gaps. To ensure heat transfer across all tolerance levels, such thermally conductive materials are typically dosed to the maximum possible gap size and thus usually to a relatively high degree of overfilling relative to a nominal and, above all, a minimum tolerance.

[0003] Batteries for motor vehicles typically comprise multiple battery modules, often containing multiple battery cells. Such battery modules are held by support structures, for example, in the form of battery frames or the like. Such support structures can have heat transfer surfaces, for example, in the form of bulkhead plates as an intermediate layer, cooling plates, other cooling structures, or more generally, heat sinks, through which excess heat is to be dissipated from the battery cells and thus from the battery modules to a cooling system of the battery. Due to manufacturing tolerances, batteries, for example, may have different shapes and positions of bulkhead plates, battery frames, undersides of battery modules, and different positions of connection points on battery frames and battery modules.

[0004] Because a certain degree of overfilling with thermal interface material, i.e. in the form of thermal interface material or gap filler, is often accepted, very high forces can sometimes occur during assembly, especially when positioning the battery modules, as these compress and displace the already applied thermal interface material (thermal interface material or gap filler). Furthermore, very long process times may have to be accepted, as the already applied thermal interface material can only be compressed very slowly in order to keep the resulting forces to a minimum and to avoid damage to the structures, particularly the battery modules and battery module support structures. If the gap to be filled is not sufficiently filled with thermal interface material, there is a risk of very poor thermal performance of the associated cooling system.Underdosing with thermal conductive material is therefore also disadvantageous.

[0005] Furthermore, overfilling with thermal interface material involves high material usage and thus high costs. This also represents a waste of resources and thus leads to a poor environmental impact. Furthermore, commonly used thermal interface materials usually have a density of more than 2 g / cm³. 3 They therefore have a relatively high weight, which the motor vehicle in question has to bear over its lifetime, which has a correspondingly negative impact on the energy balance of the vehicle.

[0006] From the document DE 10 2018 005 234 A1 a method for producing a battery for a motor vehicle is known. Description of the invention

[0007] It is therefore the object of the present invention to provide a solution by means of which at least one thermal interface in a battery for a motor vehicle can be produced as effectively as possible.

[0008] This object is achieved by a method and a system for producing a thermal interface in a battery for a motor vehicle having the features of the independent patent claims. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the dependent claims.

[0009] In the method according to the invention for producing a thermal interface in a battery for a motor vehicle, at least one battery module and at least one receiving structure with a receiving region having a heat transfer surface for receiving one side of the battery module in a designated installation position are provided. The battery module can, for example, have a plurality of interconnected battery cells which are arranged in a housing of the battery module. The receiving structure can, for example, be a battery frame or other receiving structures. The receiving structure includes the said heat transfer surface, which can, for example, be a bulkhead plate. In the case of a bulkhead plate, this is usually an intermediate layer between the battery module and the cooling system; this serves, among other things, to transfer heat from the battery module to the cooling system.The heat transfer surface can also be a cooling plate, another cooling structure, or more generally a heat sink. In its intended installation position, the heat transfer surface serves to transfer heat from the battery module to the battery's cooling system.

[0010] The battery cooling system can be active or passive, i.e. provide active cooling or passive cooling.

[0011] In the method according to the invention, the receiving area and / or the side of the battery module that can be received by the receiving area of ​​the receiving structure is measured using a measuring device. The size and shape of a gap is determined, which results in the intended installation position of the battery module between the heat transfer surface and the side of the battery module to be received. This determination is carried out using a data processing device based on the previously performed measurement. A dosage specification for a thermally conductive material, i.e., for a thermal interface material or for a gap filler, to fill the gap is then determined using the data processing device based on the determined size and shape of the gap.The thermally conductive material is then applied to the heat transfer surface and / or the side of the battery module to be mounted using a dosing device according to the determined dosage specification.

[0012] The battery module is then mounted in the intended installation position by pressing the applied thermal conductive material using an assembly device, after which the pressed thermal conductive material forms the thermal interface between the side of the battery module and the heat transfer surface.

[0013] In the method according to the invention for producing the said thermal interface, an application concept for the thermally conductive material is designed in such a way that uncertainties or tolerances are precisely recorded, processed, and analyzed by the process chain according to the invention, thus eliminating tolerance-related overfilling with the thermally conductive material. Thus, tolerance-controlled dosing of the thermally conductive material takes place, so that the material used for the thermally conductive material serving as a gap filler or thermal interface material is adapted to the actual gap geometry and thus to the actually required amount.This can be done by measuring the receiving area and / or the side of the battery module to be received using the measuring device, based on which conclusions are drawn about the size and shape of the gap that results in the intended installation position of the battery module between the heat transfer surface and the side of the battery module to be received.

[0014] Both the battery module and the mounting structure are subject to manufacturing tolerances, which can have significant effects, particularly on large assemblies and welded structures. Within the specified tolerance ranges, shape deviations in the battery modules and the mounting structure, for example, in the form of waviness or bulging, can occur. Furthermore, certain positions of attachment points or locations can vary. All of these deviations must be compensated for with the thermally conductive material. To avoid the disadvantages mentioned above due to general overfilling or an uneven or insufficient degree of wetting, the thermally conductive material is dosed locally in the appropriate quantities at the appropriate locations.

[0015] This process allows for very thin layers of thermally conductive material to be applied. This results in relatively low compression forces without overfilling the gap between the heat transfer surface of the support structure and the side of the battery module that is supported by the support structure. The required layer thicknesses of the thermally conductive material thus depend almost exclusively on the tolerances of the battery module and the support structure themselves, and no longer on additional process-related influences, such as the high forces that otherwise occur when pressing the applied thermally conductive material, which can cause the support structure and / or the battery module to bend at certain points.

[0016] The method also makes it possible to reliably adjust the degree of wetting of the thermally conductive material, thus achieving the most ideal thermal properties possible for the thermally conductive material. For example, the method according to the invention can achieve a constant thermal resistance by adjusting the degree of wetting of the thermally conductive material to a local layer thickness. The degree of wetting can, for example, describe the percentage coverage of a defined surface with thermally conductive material.

[0017] Based on the measurement of the mounting area and / or the side of the battery module to be mounted using the mounting area, a general tolerance level can be determined. In particular, local and global differences can also be captured. Furthermore, it is also possible to consider compensation functions for over-determined connection or support points, so that a required dosing volume for the thermal interface material can be determined depending on the aforementioned parameters.

[0018] Using this method, it is possible to precisely adjust the dosage of thermally conductive material to the actual size and shape of the gap that arises between the heat transfer surface and the side of the battery module to be mounted in the intended installation position of the battery module. Not only can the total quantity of thermally conductive material be precisely adjusted, but based on the measurement, it is also possible to specifically determine the shape and size of the gap in question and precisely adapt the thermally conductive material to it. The typically relatively expensive thermally conductive material is therefore not wasted using the method according to the invention. This also results in a corresponding conservation of the environment and resources.

[0019] Because overfilling with thermally conductive material is no longer necessary in the method according to the invention, corresponding weight savings can also be achieved for the battery in question. Furthermore, for the reasons mentioned above, particularly good thermal properties can be achieved at the thermal interface. Furthermore, particularly low forces result when mounting the battery module, by means of which the applied thermally conductive material is compressed. The assembly device used to mount the battery module can therefore be dimensioned accordingly smaller, which results in a lower investment in the system. The structural load in the receiving structure and in the battery module can also be reduced accordingly. Furthermore, the method according to the invention makes it possible to achieve particularly short process times when setting the battery module and when compressing the thermally conductive material.

[0020] A further possible embodiment of the invention provides that at least one of the following variables is recorded during the measurement: - shape of the heat transfer surface, in particular undulations and / or bulges; - shape of the side of the battery module, in particular any undulations and / or bulges; - Location of attachment points of the receiving area; - Location of mounting points on the side of the battery module.

[0021] By measuring the shape of the heat transfer surface and / or the battery module, it is possible to determine with particular precision the size and shape of the gap that results between the heat transfer surface and the side of the battery module being mounted when the battery module is installed as intended. In particular, by measuring or recording undulations and / or bulges, it is possible to predict the resulting gap shape with particular precision. Considering attachment points on the mounting area and / or the side of the battery module being mounted also provides valuable information for setting the most precise dosage specifications for the thermal interface material.In principle, all geometric properties of the receiving area and / or the side of the battery module to be recorded can be measured during the process, which affect the size and shape of the gap to be filled with the thermal interface material. The more precise the measurement, the more precise the size and shape of the gap and thus the corresponding dosage specifications for the thermal interface material can be.

[0022] A further embodiment of the invention provides for the measurement to be carried out using a 3D camera system, a laser measuring device, or a measuring probe. The measuring device can therefore comprise optical systems or tactile systems to perform the measurement. Ideally, the measurement is carried out continuously or at least using a correspondingly finely resolved, discrete measuring grid. In particular, shape deviations and positional deviations within the permissible tolerances are reliably recorded in the recording area and / or the side of the battery module to be recorded. To increase measurement accuracy or to validate the measurement results, various optical and / or tactile measuring systems can also be combined.

[0023] A further embodiment of the invention provides that, when determining the dosing specification, the heat transfer surface and / or the side of the battery module is divided into individual segments, with respective individual volumes of the thermally conductive material being defined for each segment. During the measurement process, measurement data is obtained on the basis of which a general tolerance level can be determined with regard to the receiving area of ​​the receiving structure and / or the side of the battery module to be accommodated. Local and global differences can also be recorded. Furthermore, it is also possible to consider compensation functions for specific support points or contact points and, based on this, to determine the required dosing volume of the thermally conductive material.By dividing the heat transfer surface and / or the side of the battery module to be applied into individual segments when determining the dosing specification, it is possible to assign individual volumes of thermally conductive material to each segment in a particularly effective manner. This results in a particularly easy-to-implement dosing specification for the dosing device used.

[0024] According to the invention, local differences in the stiffness of the support structure and / or the battery module are taken into account when determining the dosage specification. For example, a certain excess amount of thermally conductive material can be provided in a central region to compensate for deflection or gap enlargement during the pressing of the applied thermally conductive material. If the support structure is a battery frame, for example, it can have different stiffnesses in certain frame zones. Such different stiffnesses can have a corresponding effect on the pressing of the thermally conductive material, so that these properties can also be taken into account when determining the dosage specification.By taking into account local differences in the stiffness of the support structure and / or the battery module, it is possible to adapt the dosage specification with regard to the thermal conductivity material particularly precisely to the actual conditions.

[0025] According to a further embodiment of the invention, it is provided that the thermally conductive material is applied in the form of a plurality of lines, wherein, when determining the dosage specification, the respective cross-sections of the lines are specified and locally adapted depending on the size and shape of the gap to be filled. In other words, a type of linear application pattern is selected as the application form for the thermally conductive material, in which the thermally conductive material is applied in the form of a plurality of lines or beads. This is particularly advantageous in connection with the aforementioned segment-like subdivision of the heat transfer surface and / or the side of the battery module to be accommodated. This is because this type of linear application pattern for the thermally conductive material can be easily applied to the discrete elements or segments.Such a linear application pattern can be easily distributed over the surface to be thermally bonded, i.e., the heat transfer surface of the receiving structure and / or the side of the battery module to be bonded, and divided into segments. The thermally conductive material can be applied in the form of linear beads of various cross-sectional shapes, for example, round or triangular. This application pattern, in the form of multiple lines of the thermally conductive material, allows for particularly simple and precise implementation of the dispensing specifications.

[0026] According to a further embodiment of the invention, it is provided that by regulating a flow rate and / or dosing speed, the cross-sections of the lines are locally adjusted in accordance with the dosing specification during application of the thermally conductive material. Local volume control during application of the thermally conductive material can, for example, be achieved very simply by varying the thickness, the height or, more generally, the cross-section. This can be achieved very simply, for example, by regulating the flow rate and / or the dosing speed - i.e. the feed speed at which, for example, a dosing head of the dosing device is moved forward. In this way, it is possible precisely and easily to implement the determined dosing specification accordingly during application of the thermally conductive material. Regardless of how or in what form the thermally conductive material is applied, dosing orDesign of the material input according to the locally determined volumes of the gap.

[0027] A further embodiment of the invention provides that when determining the dosage specification, the number of lines is varied locally depending on the size and shape of the gap to be filled. In general, it is therefore also conceivable to switch the application form or application pattern during application of the thermally conductive material, for example by switching from six to three lines or beads when locally very small volumes are required and vice versa. The application pattern can therefore be adapted depending on the volume of the gap to be filled locally. This ensures that the gap between the heat transfer surface of the receiving structure and the side of the battery module to be received is not overfilled. The application form does not have to be limited to linear application forms. It is also possible, for example, to select a point-like application of the thermally conductive material.The type of application of the thermal conductive material can also be varied, for example by spraying, brushing or applying it in some other way in certain areas. The application type can also be adapted to the respective selected application method. In addition, the type of subdivision of the heat transfer surface and / or the side of the battery module into individual segments can be varied - in other words, a variation of a grid arrangement can be made. The type of sub-conduction into the segments is adapted, for example, to the respective selected application method. It is also possible to vary the application method locally. For example, a linear application method for the thermal conductive material could be selected in certain areas, whereas in other areas a point-like application of the thermal conductive material could be selected, and in yet other areas, for example, a different geometry or shape for the thermal conductive material could be selected.Distances between the selected forms of thermal conductive material can also be varied as needed to adapt the application pattern. By adapting the application pattern with regard to the size, arrangement and / or spacing between the thermal conductive material, the best possible fill level of thermal conductive material can be achieved - without applying too much or too little. The application form is understood in particular to be the shape or form according to which the thermal conductive material is applied, e.g. linear, dot-shaped or the like. The application pattern then results from the selected application form and arrangement of the thermal conductive material on the respective application surface, i.e. the heat transfer surface and / or the side of the battery module to be accommodated.The application pattern is therefore determined by the selected distances between individual areas of the applied thermal conductive material, but also by the selected application form (point-like, linear, flat, etc.) of the thermal conductive material and how large an area individual elements of the thermal conductive material are applied.

[0028] A further possible embodiment of the invention provides that a plurality of battery modules and receiving structures are measured, wherein, depending on the measurement, the battery modules are assigned to the receiving structures according to at least one predetermined assignment criterion, in particular with regard to the smallest possible dosage of thermally conductive material to fill the respective gap. In other words, a type of matching process can be carried out by measuring a plurality of battery modules and a plurality of receiving structures on both sides. This allows the best possible pairings between the respective battery modules and receiving structures to be made. This can be done, for example, with regard to the fact that the gap resulting in the intended installation position between the respective battery module and the respective receiving structure is particularly small, so that a particularly small dosage of thermally conductive material is required.It is also conceivable, for example, that the precise shape of the heat transfer surface of the receiving structure and the side of the battery module to be accommodated be taken into account, and the assignment between the respective battery module and receiving structure is carried out in such a way that a particularly uniform gap thickness and thus a particularly uniform thickness of thermally conductive material is achieved. In principle, a wide variety of assignment criteria can be specified according to which the matching or assignment of the different battery modules and receiving structures takes place.

[0029] According to another possible embodiment of the invention, the data resulting from the measurement is used to verify whether specified tolerances have been met for the mounting structure and / or the battery module. In general, the data can also be used for comparison purposes, for example, to verify whether the components in question comply with drawing specifications, e.g., with specified tolerance ranges, so that defective parts (NOK = not OK), i.e., reject parts, can be identified.

[0030] According to a further possible embodiment of the invention, it is provided that data resulting from the measurement are used to determine wear on tools and / or semi-finished products used to manufacture the receiving structure and / or the battery module. For example, the data resulting from the measurement can be precisely statistically evaluated. With knowledge of the data resulting from the measurement, it is possible to determine the extent to which certain tools or semi-finished products used to manufacture the receiving structure and / or the battery module are wearing out based on the changing shape or dimension or even position tolerances of the receiving structure and the battery module. Effects on other processes, in particular downstream processes, can thus also be identified at an early stage.

[0031] The system according to the invention for producing a thermal interface in a battery for a motor vehicle comprises a measuring device, a data processing device, a dosing device, and an assembly device, which are designed to carry out the method according to the invention or an advantageous embodiment of the method according to the invention. Advantageous embodiments of the method according to the invention are to be regarded as advantageous embodiments of the system according to the invention, and vice versa, wherein the system in particular has means for carrying out the method steps.

[0032] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer or a device.

[0033] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective specified combination, but also in other combinations or on their own, without departing from the scope of the invention. Short character description

[0034] The drawing shows: Fig. 1 a schematic cross-sectional view of a section of a battery for a motor vehicle with a battery module arranged on a receiving structure, wherein a heat-conducting material serving as a thermal interface material or as a gap filler is arranged between the battery module and the receiving structure; Fig. 2 a plan view of the receiving structure, wherein the thermally conductive material has been applied in a line in the region of a heat transfer surface of the receiving structure before the battery module is attached; Fig. 3 a visualization of data obtained during the measurement of the recording area; and in Fig. 4 a schematic representation by means of which a determination of a dosage specification for the thermal conductive material and the application of the thermal conductive material is shown.

[0035] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0036] A battery 10 for a motor vehicle is shown in detail in a schematic side view in Fig. 1. The battery 10 can have a plurality of battery modules 12, although only one of the battery modules 12 is schematically illustrated here. The battery modules 12 can, for example, comprise a plurality of interconnected lithium-ion cells arranged in a housing of the battery module 12 (not shown in detail). Furthermore, a heat transfer surface 14 can be seen, which belongs to a receiving structure (not shown in detail here) for receiving the battery module 12. The heat transfer surface 14 can, for example, be a bulkhead or a housing side with a heat sink or cooling plate.

[0037] When the battery module 12 is installed as intended, a gap (not specified here) exists between the underside 16 of the battery module 12 and the heat transfer surface 14. This gap is largely filled with a thermally conductive material 18. The thermally conductive material 18 is a thermal interface material or a so-called gap filler. The thermally conductive material 18 serves to ensure the best possible thermal connection and thus heat transfer from the battery module 12 to the heat transfer surface 14. For this purpose, it is important, among other things, that the gap between the underside 16 of the battery module 12 and the heat transfer surface 14 is filled with as little air inclusions as possible.

[0038] Due to manufacturing constraints, it is usually not possible to always manufacture the battery modules 12, and in particular the heat transfer surface 14, exactly the same. For cost reasons alone, certain tolerances are therefore specified or permitted within which dimensional variations, positional variations, and shape variations may occur in the battery module 12 and the heat transfer surface 14. A tolerance range 20 with respect to the shape of the underside 16 of the battery module 12 is shown schematically here. Likewise, a tolerance range 22 with respect to the shape of the heat transfer surface 14 is indicated schematically.

[0039] Different wavinesses or protrusions may therefore arise on the underside 16 and on the heat transfer surface 14, which may occur purely for manufacturing reasons and are also tolerated within the tolerance ranges 20, 22. Furthermore, the respective connection points 24, 26 on the underside 16 of the battery module 12 and in the area of ​​the heat transfer surface 14 are schematically indicated. Certain tolerance ranges 28, 30 are also permissible for the connection points 24, 26. In particular, certain positional tolerances may arise with regard to the connection points 24, 26.

[0040] Due to the different tolerance ranges 20, 22, 28, and 30, a certain degree of flexibility arises with regard to the size and shape of the gap, which must be filled with the thermally conductive material 18. A minimum gap height 32 and a maximum gap height 34 are schematically shown, which can result when all tolerances are exhausted. Depending on the minimum and maximum gap heights 32 and 34, a corresponding metering volume 36 results for the smallest possible gap and a metering volume 38 for the maximum gap size.

[0041] In Fig. 2 shows a partial perspective view of the aforementioned receiving structure 40 of the battery 10. The previously mentioned heat transfer surface 14 can be seen here, on which the heat-conducting material 18 was applied in the form of several lines 42, even before the battery module 12 was installed. The connection points 26 in the region of the heat transfer surface 14 can be seen here; these connection points are in the form of screw tabs. The receiving structure 40 has a battery frame 44 and several receiving areas 46 enclosed by the frame, each of which serves to receive one of the battery modules 12 with its respective underside 16.The lines 42 of the thermally conductive material 18 are pressed during assembly of the respective battery modules 12 and subsequently form a respective thermal interface between the underside 16 of the respective battery module 12 and the heat transfer surface 14 of the respective receiving area 46. A method for producing the thermal interfaces is explained in more detail with reference to the following figures.

[0042] In Fig. 3 shows one of the receiving areas 46 of the battery 10 in a plan view, illustrating a measurement result relating to the heat transfer surface 14 of the receiving area 46 shown here. The receiving area 46 is measured using a schematically indicated measuring device 48. The measuring device can, for example, comprise a 3D camera system, a laser measuring device, a measuring probe, and / or the like. During the measurement of the receiving area 46, in particular, a shape of the heat transfer surface 14 is detected and measured, especially waviness and / or protrusions. In addition, a respective position of the connection points 26 serving as fastening points is preferably also measured and thus recorded. It is also possible to measure and record the shape of the underside 16 of the respective battery module 12, which is to be inserted into the receiving area 46, especially with regard to waviness and / or protrusions.In the same way, the respective positions of the connection points 24 (see . Fig. 1) of the battery module 12 are recorded and measured.

[0043] In this case, data obtained during the measurement of the receiving area 46 has been visualized in the form of unspecified contour lines. This allows, above all, the aforementioned waviness and / or bulging of the heat transfer surface 14 to be precisely quantified. The same can also be done additionally or alternatively with respect to the battery module 12.

[0044] Depending on the measurement, the size and shape of the gap in question is determined, which results in the intended installation position of the battery module 12 in question between the heat transfer surface 14 and the underside 16 of the battery module 12. This determination, i.e. evaluation and analysis, of the relevant measurement results can be carried out using a schematically indicated data processing device 50. After the size and shape of the gap in question have been determined, a dosing specification for the thermally conductive material 18 is determined based on this using the data processing device 50, which should fill the gap between the underside 16 of the battery module 12 and the relevant heat transfer surface 14. Data relating to the dosing specification is transmitted from the data processing device 50 to a dosing device 52, which is also only indicated schematically here.

[0045] This dosing device 52 then takes over the application of the heat conducting material 18, for example as in Fig. 2, in the form of individual lines 42. After the thermally conductive material 18 has been applied, the actual assembly of the battery module 12 takes place in the receiving area 46. The assembly is carried out using an assembly device 54, which is also only indicated schematically here. The measuring device 48, the data processing device 50, the dosing device 52, and the assembly device 54 together form a system 56 for producing respective thermal interfaces within the battery 10, which are formed from thermally conductive material 18.

[0046] During the assembly of the battery module 12, the underside 16 of the respective battery module 12 comes into contact with the individual lines 42 of the applied or introduced thermally conductive material 18. During the installation process of the battery module 12, the individual lines 42 are compressed, after which the compressed thermally conductive material 18 then forms the aforementioned thermal interface between the underside 16 of the respective battery module 12 and the heat transfer surface 14. From the measurement data obtained by the measuring device 48, the data processing device 50 thus determines a type of general tolerance level, recording local and global differences. The dosing specification is preferably determined using an algorithm implemented on the data processing device 50.

[0047] In Fig.Figure 4 schematically shows a possible procedure for evaluating the measurement and converting it into the specified dosing. When determining the specified dosing, the heat transfer surface 14 is divided into individual tracks 58. The individual tracks 58 can then in turn be subdivided into individual segments 60, which is shown schematically below the individual lines 42, along which the thermally conductive material 18 is applied to the heat transfer surface 14. For the individual segments 60, respective individual volumes relating to the thermally conductive material 18 to be applied can be specified during the determination of the dosing. In this way, local conditions regarding the shape and size of the gap to be filled can be easily taken into account. The calculation of the individual volumes is then translated orassigned to the respectively selected application form, in the present case in the form of the five lines 42, according to which the dosing device 52 applies the heat-conducting material 18 to the heat transfer surface 14.

[0048] As schematically illustrated at the top right, a cross-section 62 of the respective lines 42 can be varied in order to locally fill the existing gap between the underside 16 of the respective battery module 12 and the heat transfer surface 14 as optimally as possible and without overdosing. When determining the dosing specification, local differences in the stiffness of the receiving structure 40 and / or the battery module 12 can also be taken into account. For example, it is possible to plan or provide a certain excess amount of thermally conductive material in a determined area to compensate for deformations or elasticities of the thermally conductive material 18 or the battery module 12 and / or the receiving structure 40.

[0049] As can be seen here, it is intended to apply the thermally conductive material 18 in the form of the respective lines 42 by means of the dosing device 52. When determining the dosing specification, for example, the said cross-sections 62 of the respective lines 42 can be adjusted depending on the size and shape of the gap to be locally filled. By regulating a flow rate and / or dosing speed in the dosing device 52, the cross-sections 62 of the respective lines 42 can be locally adjusted during the application of the thermally conductive material 18 in accordance with the corresponding dosing specification. This is indicated schematically here by the line thickness of the individual lines 42 being shown partially differently depending on the segment 60.

[0050] It is also possible to vary the selected application pattern, for example by locally changing the number of lines 42. For example, in an area where relatively little thermal conductive material 18 is required to fill the gap, it is possible to provide only three lines 42 instead of the five lines 42 shown here. Of course, more than five lines 42 can be applied if required. The shape of the cross sections 62 of the lines 42 is selected to be round here only as an example. In principle, any cross sections 62 or cross-sectional shapes are possible, so that the lines 42 can also have triangular, rectangular or otherwise shaped cross sections 62. Instead of the linear application pattern shown here, it is also possible to select other application patterns.

[0051] After the lines 42 have been metered or applied, the thermally conductive material 18 applied or introduced by the lines 42 is pressed within a specific process window by mounting or inserting the respective battery module 12. This process of positioning the respective battery module 12 can also be performed downstream, depending on the specific thermally conductive material used as a gap filler or thermal interface material. After the respective battery module 12 has been mounted and inserted, the individual lines 42 are pressed such that they fill the previously existing gap between the underside 16 of the respective battery module 12 and the heat transfer surface 14, at least substantially without any air inclusions. This results in a particularly good thermal interface between the respective battery module 12 and the heat transfer surface 14.

[0052] It is also possible that, before determining the dosage specification, several of the battery modules 12 and several of the receiving structures 40 are measured, wherein, depending on the measurement, the respective battery modules 12 are assigned to the respective receiving structures 40 according to at least one predetermined assignment criterion. The assignment criterion can, for example, include requiring the smallest possible dosage amount of the thermally conductive material 18. It is also possible for the assignment criterion to include ensuring that the thermally conductive material 18 has the most uniform thickness possible.

[0053] By measuring the battery modules 12 and the receiving structure 40 from both sides, the most suitable battery module 12 can be selected for the most suitable receiving area, in this case in the form of respective frame compartments, of the receiving structure 40. In general, the data resulting from the measurement can also be used for comparison, for example, to check whether the battery modules 12 and the receiving structure 40 meet the respective drawing specifications or validity ranges with regard to respective tolerances, so that defective parts can be identified. It is also possible to precisely statistically evaluate the measurements so that, for example, trends with regard to wear on molds or semi-finished products used to manufacture the respective battery modules 12 and / or the receiving structure 40 can be identified.Such analyses can also have an impact on processes, especially subsequent processes, and can therefore be detected early. LIST OF REFERENCE SYMBOLS 10 Battery 12 Battery module 14 Heat transfer surface 16 Bottom of the battery module 18 Thermal conductive material 20 Tolerance range regarding the shape of the bottom of the battery module 22 Tolerance range regarding the shape of the heat transfer surface 24 connection points of the battery module 26 connection points in the area of ​​the heat transfer surface 28 Tolerance range with regard to the position of the connection points of the battery module 30 Tolerance range with regard to the position of the connection points in the area of ​​the heat transfer surface 32 minimum gap height 34 maximum gap height 36 Dosing volume at minimum gap 38 Dosing volume at maximum gap height 40 Recording structure 42 lines 44 battery frames 46 Recording area 48 measuring device 50 data processing facility 52 Dosing device 54 Mounting device 56 Systems 58 lanes 60 segments 62 Cross section of the lines

Claims

[1] Method for producing a thermal interface in a battery (10) for a motor vehicle, comprising the steps: - Providing at least one battery module (12) and at least one receiving structure (40) with a receiving area (46) having a heat transfer surface (14) for receiving one side (16) of the battery module (12) in a proper installation position; - measuring the receiving area (46) and / or the side of the battery module (12) by means of a measuring device (48); - determining a size and shape of a gap which results in the intended installation position of the battery module (12) between the heat transfer surface (14) and the side (16) of the battery module (12), by means of a data processing device (50) on the basis of the measurement; - determining a dosage specification for a thermally conductive material (18) for filling the gap on the basis of the determined size and shape of the gap by means of the data processing device (50); - applying the heat-conducting material (18) to the heat transfer surface (14) and / or the side (16) of the battery module (12) in accordance with the determined dosing specification by means of a dosing device (52); - Mounting the battery module (12) in the intended installation position by pressing the applied thermally conductive material (18) by means of a mounting device (54), after which the pressed thermally conductive material (18) forms the thermal interface between the side (16) of the battery module (12) and the heat transfer surface (14), wherein local differences in stiffness of the receiving structure (40) and / or the battery module (12) are taken into account when determining the dosage specification. [2] Method according to claim 1, characterized bythat at least one of the following quantities is recorded during the measurement: - shape of the heat transfer surface (14), in particular undulations and / or protrusions; - shape of the side (16) of the battery module (12), in particular undulations and / or protrusions; - location of attachment points of the receiving area (46); - Location of fastening points on the side (16) of the battery module (12). [3] Method according to claim 1 or 2, characterized by that the measurement is carried out using a 3D camera system, a laser measuring device and / or a measuring probe. [4] Method according to one of the preceding claims, characterized by that when determining the dosing specification, the heat transfer surface (14) and / or the side (16) of the battery module (12) is divided into individual segments (60), wherein respective individual volumes relating to the heat-conducting material (18) are determined for the individual segments (60). [5] Method according to one of the preceding claims, characterized by that the heat-conducting material (18) is applied in the form of a plurality of lines (42), wherein, when determining the dosage specification, respective cross sections (62) of the lines (42) are specified in a locally adapted manner depending on the size and shape of the gap to be filled. [6] Method according to claim 5, characterized by that by controlling a flow rate and / or dosing speed, the cross sections (62) of the lines (42) are locally adapted according to the dosing specification when applying the heat-conducting material (18). [7] Method according to claim 5 or 6, characterized by that when determining the dosing specification, the number of lines (42) is varied locally depending on the size and shape of the gap to be filled. [8] Method according to one of the preceding claims, characterized bythat a plurality of battery modules (12) and receiving structures (40) are measured, wherein, depending on the measurement, the battery modules (12) are assigned to the receiving structures (40) according to at least one predetermined assignment criterion, in particular with regard to the smallest possible dosage amount of the heat-conducting material (18) for filling the respective gap. [9] Method according to one of the preceding claims, characterized by that data resulting from the measurement are used to check whether specified tolerances have been observed in the receiving structure (40) and / or in the battery module (12). [10] Method according to one of the preceding claims, characterized by that data resulting from the measurement are used to determine wear on tools and / or semi-finished products which are used to manufacture the receiving structure (40) and / or the battery module (12). [11] System (56) for producing a thermal interface in a battery (10) for a motor vehicle, comprising a measuring device (48), a data processing device (50), a dosing device (52) and an assembly device (54), which are designed to carry out a method according to one of the preceding claims.

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