Cooling unit for use in a battery module, battery module, method for its manufacture and vehicle with battery module

Abstract

Cooler unit (10, 20, 30) for use in a battery module (40), comprising a cooler (1) and a compressible heat-conducting compound (2) which is materially bonded to the cooler (1) by curing.

Description

[0001] The present invention relates to a cooler unit for use in a battery module, a battery module, and methods for producing the cooler unit and the battery module. Furthermore, the invention also relates to a vehicle, in particular a motor vehicle, with a battery module.

[0002] Batteries are generally known from the prior art. DE 10 2011 103 993 A1 describes a battery module with individual battery cells that includes a cooling element to improve heat dissipation and thus the cooling effect. An additional insulating film ensures electrical insulation of the individual battery cells from the cooling element. In addition, a tolerance compensation element is provided to compensate for manufacturing component tolerances. This element is formed in one piece or integrally with the insulating film. The disadvantage of manufacturing such complexly structured battery modules is that it requires a high level of material usage and that assembly that takes component tolerances into account is difficult. Assembly often leads to defects between the components to be connected or to geometric or functional impairments of the components.In addition, disassembling the battery module, for example for service purposes or to replace the cooling element, is difficult.

[0003] DE 10 2011 084 002 A1 discloses a thermal transition device for establishing a thermal transition between an energy storage device and a temperature control plate for controlling the temperature of the energy storage device. The thermal transition device comprises a thermal insulation layer made of an insulation material distributed unevenly across the thermal insulation layer and a tolerance compensation layer made of a compressible material for compensating for different material thicknesses of the thermal insulation layer.

[0004] Based on this prior art, the object of the present invention is to provide a cooler unit that, while having a simple structure, is characterized by very good heat-conducting properties and the ability to compensate for dimensional and manufacturing-related tolerances and component tolerances, and is also easy to assemble and disassemble for servicing. Furthermore, the object of the invention is to provide a battery module and a vehicle that are characterized by reliable and permanently high performance with a good running range and reduced effort for servicing. Furthermore, the object of the present invention is to provide simple and cost-effective methods for producing a cooler unit and a battery module that can be implemented without high technical complexity.

[0005] The object is achieved by a cooler unit for use in a battery module. The cooler unit according to the invention comprises a cooler and a compressible thermally conductive compound which is materially bonded to the cooler by curing. A thermally conductive compound, and among these a thermally conductive potting compound, within the meaning of the invention is a plastic compound which is used to fill gaps and joints and the like and enables heat transport through this compound so that the battery module can be effectively cooled and protected from overheating. Because the thermally conductive compound is at least partially flowable before curing, an intimate connection with the cooler can be established. At the same time, an ideally designed connection surface for the arrangement of battery cells is created on the side of the thermally conductive compound facing away from the cooler.When the thermal compound hardens, for example through heat or radiation, the cooler and the thermal compound are permanently and firmly bonded to one another. The cooler and the thermal compound thus form a single unit, i.e. a component characterized by a simple structure but high functionality, as well as easy installation and, in the event of servicing, quick, uncomplicated and non-destructive replacement. The cooler unit can be stored separately. The application and curing of the thermal compound also has the further advantage that it can be applied selectively or locally to designated areas of the cooler, effectively saving material and thus manufacturing costs as well as the weight of the cooler unit. The assembly process in the battery module is also significantly less sensitive to contamination and climatic influences.Due to the compressible properties of the cured thermal compound, manufacturing-related tolerances and component tolerances can be very well compensated during assembly of the battery module.

[0006] The subclaims contain advantageous developments and refinements of the invention.

[0007] To further simplify the structure of the cooler unit, the thermal compound is designed to be electrically insulating. Additional insulation layers are thus eliminated. Electrical insulation can be provided either by a layer of thermal compound of appropriate thickness or by an electrically insulating material composition.

[0008] By providing an additional form-fitting connection between the cooler and the thermal compound, the stability of the cooler unit can be increased and thus its susceptibility to deformation under mechanical influences, e.g. during storage or the assembly process, can be reduced.

[0009] The thermally conductive compound is advantageously provided on at least two opposite sides of the cooler, as the cooler unit according to the invention is thus suitable for use as a heat sink on both sides, or for simultaneous application on multiple battery cells. The thermally conductive compound can also completely surround the cooler's perimeter. This has the advantage that the virtually closed shape of the thermally conductive compound around the cooler creates a particularly good connection between the cooler and the thermally conductive compound.

[0010] A further advantageous development provides that the thermally conductive compound is designed in such a way, both in terms of shape and layer thickness, that it can compensate for manufacturing-related tolerances and component tolerances of the battery module components. This enhances the effect already achieved by the compressibility of the thermally conductive compound and also enables the installation of components with high dimensional fluctuations.

[0011] Furthermore, the invention also provides a method for producing a cooler unit as described above for use in a battery module, which is characterized by the steps of i) applying a compressible thermally conductive compound to at least one side of a cooler and ii) curing the thermally conductive compound. The method enables material-saving and thus cost-reduced mass production of a simply structured and thus easy-to-assemble cooler unit. The smooth surface of the thermally conductive compound obtained by curing effectively prevents contamination of the cooler unit, which could lead to imperfections or assembly defects during assembly in the battery module.

[0012] The advantages, advantageous effects and further developments mentioned for the cooler unit according to the invention also apply to the method according to the invention for producing a cooler unit.

[0013] Due to the advantageous development of the method according to the invention, that the thermally conductive compound is applied in a shape and layer thickness that compensates for production-related tolerances and component tolerances of components of the battery module, the attachment of additional tolerance compensation elements can be dispensed with, which simplifies the manufacturing effort of the cooler unit and supports its precise installation.

[0014] A further advantageous development provides for the application of the thermal compound to at least two opposite sides of the cooler. This significantly increases the functionality of the cooler unit without significantly increasing the complexity of the manufacturing process. The cooler unit is thus suitable for installation between multiple battery cells or can function as a two-sided heat sink, eliminating the need for additional separate heat dissipation elements. The thermal compound can also be applied to the cooler in such a way that it essentially completely surrounds it. As the thermal compound hardens, it then shrinks onto the cooler. This supports the bond between the cooler and the thermal compound.

[0015] The invention also describes a battery module comprising a plurality of battery cells combined to form a cell stack and at least one separately handleable cooler unit as described above. The battery module is characterized by high power density, good operating range, and reduced service effort in the event of repairs. By forming the cooler and the thermally conductive compound as a single component without further irreversible fixation of the unit to at least one other component of the battery module, disassembly and, if necessary, replacement of the cooler unit can be carried out without impairing the remaining components of the battery module. This saves time and costs for assembly of the battery module and for servicing.Furthermore, due to the compressible properties of the thermally conductive compound, component tolerances and manufacturing-related tolerances of the battery module components can be optimally compensated without the provision of additional tolerance compensation elements.

[0016] The present invention also relates to a method for producing a battery module with multiple battery cells combined to form a cell stack. The method is characterized by the step i) arranging a cooler unit as described above on a cell base or a side surface of the cell stack such that the thermally conductive compound connects the cell stack to the cooler, or the alternative step ii) arranging a cooler unit as described above such that the cooler unit is connected to at least one battery cell. By designing the highly functional cooler unit according to the invention as a single component, additional assembly of tolerance compensation elements and separate heat dissipation elements is unnecessary. Disassembly of the cooler unit, for example, during servicing, is also easily possible without leaving residues and without damaging the other components of the battery module.The cooler unit's compressibility and tolerance-compensating properties allow for precise assembly of the battery module. This process is simple, cost-effective, and suitable for series production of battery modules.

[0017] The invention also describes a vehicle, in particular a motor vehicle, comprising at least one battery module as described above. The vehicle according to the invention is characterized by high power density with a good running range and reduced maintenance effort.

[0018] The advantages, advantageous effects and further developments mentioned for the cooler unit according to the invention and the method according to the invention for producing a cooler unit also apply to the battery module according to the invention, the method according to the invention for producing a battery module and the vehicle according to the invention.

[0019] The solutions according to the invention and their further developments result in the following advantages: - The cooler unit has a simple structure and a material-saving and thus cost-saving design, offering high functionality. - The cooler unit can be designed to be electrically insulating. - Due to the design of the cooler unit as a single unit, i.e. as a single component, assembly and disassembly are easy. - The cooler unit is resistant to contamination. - Additional heat dissipation elements, tolerance compensation elements and electrical insulation layers are not necessary. - The processes for manufacturing the cooler unit and the battery module are simple and therefore cost-effective without high technical expenditure, and can even be implemented in series production with high cycle times. - The battery module has a simple structure and requires a minimal number of functional layers. - Manufacturing tolerances of the battery cells, cell stack and cooler are compensated and air gaps between the components are eliminated. - The vehicle is characterized by high reliability and long range with low service requirements.

[0020] Further details, features, and advantages of the invention will become apparent from the following description and the figures. They show: Fig. 1 is a schematic view of a cooler unit according to a first advantageous development of the invention, Fig. 2 a schematic view of a cooler unit according to a second advantageous development of the invention, Fig. 3 a sectional view of a cooler unit according to a third advantageous development of the invention and Fig. 4 a schematic view of a battery module according to an advantageous development.

[0021] The present invention is explained in detail using exemplary embodiments. The figures show only the relevant parts of the cooler unit and the battery module; all other elements have been omitted for clarity.

[0022] In detail, Fig. 1 shows a cooler unit 10 formed from a cooler 1 and a thermally conductive compound 2 as a single component. The cooler 1 has a top side 4 and a bottom side 3, with the thermally conductive compound 2 being arranged on the underside of the cooler 3. The thermally conductive compound 2 is bonded to the underside of the cooler 3 in a materially bonded and preferably also form-fitting manner. The thermally conductive compound 2 is compressible and preferably elastic, allowing it to adapt to its mounting environment and compensate for component tolerances and manufacturing tolerances of the surrounding components. It allows heat to be transferred from any battery cells mounted on it to the cooler 1. The cooler unit 10 thus enables effective overheating protection and good cooling performance.

[0023] Preferably, the thermally conductive compound 2 is electrically insulating. This can be achieved by a corresponding layer thickness of the thermally conductive compound 2 or a corresponding material composition of the thermally conductive compound 2.

[0024] To produce the cooler unit 10, a flowable heat-conducting compound is applied to the desired locations of the cooler 1, in Fig. 1 is applied, for example, to the underside 3 of the cooler 1, either over a large area or at specific points or locally, and then cured. The use of a thermally conductive compound 2 enables, on the one hand, a good, material-to-material bond with the cooler 1, and, on the other hand, a surface with a high surface quality and no unevenness is formed on the exposed side of the thermally conductive compound 2, which enables optimal contact with other components.

[0025] The curing process also makes the thermal compound 2 dirt-resistant, so that during assembly of the cooler unit 10, defects or assembly defects caused by adhering particles can be effectively avoided.

[0026] The cooler unit 10 is easy to assemble and can be disassembled without causing any damage in the event of maintenance.

[0027] Fig. Figure 2 shows a second embodiment of a cooler unit. The cooler unit 20 shown here differs from the cooler unit 10 of Fig. 1 in that the thermally conductive mass 2 is applied to two opposite sides 3 and 4 of the cooler 1. The cooler unit 20 is thus particularly suitable for installation between battery cells.

[0028] Fig. Figure 3 shows a third embodiment of a cooler unit in section. The cooler unit 30 shown here differs from the cooler unit 20 of Fig. 2 in that the thermally conductive mass 2 completely encloses the cooler 1 at the circumference.

[0029] Fig. 4 shows a battery module 40 comprising battery cells 5 combined to form a cell stack 6. The number of battery cells 5 is not limited and depends on the desired performance of the battery module 40. The cell stack 6 can be braced in a conventional manner, for example, by a frame surrounding the battery cells 5, thereby securing the geometric arrangement of the cell stack 6 and ensuring a good connection between the battery cells 5.

[0030] A cooler unit 10 is arranged at the bottom of the cell stack 6 / at the cell bottom 7, so that the thermally conductive compound 2 of the cooler unit 10 connects the cell stack 6 to the cooler 1 in a thermally conductive manner. This ensures good thermal conduction of heat present in the cell stack 6 away from the cell stack 6, which contributes to a long service life of the battery module 40. Alternatively, the cooler unit 10 can also be arranged on a side surface of the cell stack 6.

[0031] Due to its compressibility, and preferably also its shape and layer thickness, the thermally conductive compound 2 also compensates for component tolerances and dimensional tolerances of the cell stack 6 as well as unevenness, prevents air inclusions and thus ensures good thermal conductivity.

[0032] The thermally conductive compound 2 is advantageously electrically insulating and thus prevents unwanted electrical contact between the battery cells 5.

[0033] The foregoing description of the present invention is for illustrative purposes only and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention and its equivalents. List of reference symbols: 1 cooler 2 thermal compound 3 Bottom of the cooler 4 Top of the cooler 5 battery cells 6 cell stacks 7 Cell floor 10 cooler unit 20 cooler unit 30 cooler unit 40 battery module

Claims

[1] Cooler unit (10, 20, 30) for use in a battery module (40), comprising a cooler (1) and a compressible heat-conducting compound (2) which is materially bonded to the cooler (1) by curing. [2] Cooling unit (10, 20, 30) according to claim 1, characterized by that the thermally conductive mass (2) is electrically insulating. [3] Cooling unit (10, 20, 30) according to claim 1 or 2, characterized by that the cooler (1) and the thermally conductive mass (2) are positively connected to each other. [4] Cooling unit (10, 20, 30) according to one of the preceding claims, characterized by that the heat-conducting mass (2) is provided on at least two opposite sides (3, 4) of the cooler (1). [5] Cooling unit (10, 20, 30) according to one of the preceding claims, characterized bythat the heat-conducting compound (2) is designed in shape and layer thickness such that it can compensate for manufacturing-related tolerances and component tolerances of components of the battery module (40). [6] Method for producing a cooler unit (10, 20, 30) according to one of claims 1 to 5 for use in a battery module (40), characterized by the steps: - applying a compressible heat-conducting compound (2) to at least one side (3, 4) of a cooler (1) and - Curing of the thermal compound (2). [7] Method according to claim 6, characterized by that the thermally conductive compound (2) is applied in a shape and layer thickness that compensates for manufacturing-related tolerances and component tolerances of components of the battery module (40). [8] Method according to one of claims 6 or 7, characterized by the step of applying the thermally conductive compound (2) to at least two opposite sides (3, 4) of the cooler (1). [9] Battery module (40) comprising a plurality of battery cells (5) combined to form a cell stack (6) and at least one cooler unit (10, 20, 30) according to one of claims 1 to 5. [10] Method for producing a battery module (40) with a plurality of battery cells (5) combined to form a cell stack (6), comprising the step: - Arranging a cooler unit (10) according to one of claims 1 to 5 on a cell base (7) or a side surface of the cell stack (6), so that the heat-conducting mass (2) connects the cell stack (6) to the cooler (1) or - Arranging a cooler unit (20) according to one of claims 1 to 5 such that the cooler unit (20) is connected to at least one battery cell (5). [11] Vehicle, in particular motor vehicle, comprising at least one battery module (40) according to claim 9.

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