Method for manufacturing a cooling device for a battery unit, cooling device for a battery unit and battery unit

Abstract

Method for manufacturing a cooling device (1) for a battery unit (20), the cooling device (1) comprising a cavity (2) through which a cooling fluid (3) flows, the cavity comprising at least one conduit section (4) and at least one cooling section (7) connected thereto in fluid communication, wherein at least the cooling section (7) can be brought into thermal contact with the battery unit (20), and wherein the conduit section (4) comprises a plastic material and the cooling section (7) comprises a metal material, characterized in that the plastic material of the conduit section (4) and the metal material of the cooling section (7) are joined together by a nanomold process, wherein the metal material is first pretreated such that a surface of the metal material has at least a sectionual porous structure with cavities in the submicrometer range,and then the plastic material is injected onto the pre-treated metal material in such a way that the plastic material penetrates the cavities.

Description

[0001] The present invention relates to a method for producing a cooling device for a battery unit according to the preamble of claim 1, comprising a cavity through which a cooling fluid can flow, which cavity has at least one conduit section and at least one cooling section fluidly connected thereto, wherein at least the cooling section can be brought into thermal contact with the battery unit, and wherein the conduit section comprises a plastic material and the cooling section comprises a metal material. Furthermore, the invention relates to a cooling device for a battery unit according to the preamble of claim 2 and to a battery unit according to the preamble of claim 8. STATE OF THE ART

[0002] Battery units represent a source of electrical energy for many different applications in modern technology. High demands are often placed on their performance. To ensure the safety of battery units, such as lithium-ion cells or battery modules or battery packs made from these cells, and to improve their performance and service life, these battery units must be operated within a defined temperature range that is optimal for operation and storage. In particular, heating of the battery unit may be necessary when operating at low ambient temperatures. Furthermore, cooling the battery unit may prevent the temperature from becoming too high when power consumption or power output is high.By dissipating heat energy, the power output of the battery unit can be increased and the service life of the battery unit can be extended.

[0003] In this context, it is known to use a cooling fluid, such as air, water, a water-glycol mixture, or other suitable coolants, for cooling such battery units. When using electrically conductive, aqueous cooling fluids, it is necessary to conduct the cooling fluid in a cooling device to prevent damage to the battery unit in the event of contact due to an electrical short circuit.

[0004] For example, DE 10 2010 043 716 A1 discloses a battery arrangement with heat exchange elements through which a cooling fluid can flow. The heat exchange elements can be designed as a conduit arrangement, wherein the conduit arrangement can in particular also be constructed from different materials. During operation, the cooling fluid flows through the heat exchange element of the temperature control device and thus absorbs waste heat from the cooled battery arrangement. A disadvantage here is that both the battery cells and the heat exchange elements are surrounded by an embedding material. The mechanical structure of this battery arrangement is therefore complicated and limited to a specific arrangement of the battery cells and the heat exchange elements. The battery cells of the battery arrangement and the temperature control device are firmly connected to the heat-transferring embedding material.Replacing a battery cell and / or a heat exchange element of the temperature control device, as well as expanding the battery cells, particularly modularly, is not possible or only possible with considerable effort. Furthermore, the battery assembly is also heavy due to the embedding of the battery cells and the heat exchange elements in the embedding material. This can also be disadvantageous, especially in mobile applications.

[0005] The state of the art in this regard includes, for example, the documents DE 10 2010 005 154 A1, DE 10 2011 007 069 A1 and WO 2012 / 070 654 A1. DISCLOSURE OF THE INVENTION

[0006] It is therefore an object of the present invention to at least partially remedy the above-described disadvantages of known cooling devices for battery units, battery units, and methods for producing cooling devices for battery units. In particular, it is an object of the present invention to provide such a cooling device, such a battery unit, and such a method that ensure efficient cooling of battery units in a simple and cost-effective manner. In particular, the cooling device is lightweight, the mechanical structure and manufacture or assembly of the cooling device are particularly simple, and replacement of the cooling device is particularly easy.

[0007] The above object is achieved by a method for producing a cooling device for a battery unit having the features of independent claim 1, a cooling device for a battery unit having the features of independent claim 2, and by a battery unit having the features of claim 8. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the cooling device for a battery unit according to the invention naturally also apply in connection with the battery unit according to the invention and the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to each other.

[0008] In a first aspect of the invention, the object is achieved by a cooling device for a battery unit, comprising a cavity through which a cooling fluid can flow, which has at least one line section and at least one cooling section connected thereto in a fluid-communicating manner, wherein at least the cooling section can be brought into thermal contact with the battery unit, and wherein the line section comprises a plastic material and the cooling section comprises a metal material. In particular, a cooling device according to the invention is characterized in that the plastic material of the line section and the metal material of the cooling section are bonded to one another by a nanomold process.

[0009] The cooling section of the cavity of the cooling device, through which a cooling fluid flows, can be brought into thermal contact with the battery unit. This enables a transfer of thermal energy from the battery unit to the cooling fluid or, alternatively, from the cooling fluid to the battery unit. Because the cooling section is made of metal, particularly good thermal coupling can be achieved between the cooling fluid and the battery unit. This ensures particularly efficient cooling or heating of the battery unit. Operation of the battery unit within an ideal temperature range is thus possible at all times. Because the line section is made of plastic, weight can be saved. Plastic materials generally have a lower heat transfer capacity than metal materials.However, plastic materials are also, in most cases, lighter than metal materials. By using a metal material in the area of ​​the cooling device used for thermal contact with the battery unit and a plastic material in an area of ​​the cooling device not intended for thermal contact with the battery unit, both good heat transfer between the battery unit and the cooling fluid can be ensured and unnecessary weight can be saved.

[0010] According to the invention, a nanomold process is provided for the connection between the plastic material of the line section and the metal material of the cooling section. In this process, the metal material is pretreated before the actual injection molding of the plastic material onto the metal material. During this pretreatment, the surface of the metal material is modified such that, at least in some sections, it has a porous structure with cavities in the submicrometer range. Subsequently, the plastic material of the line section is injection molded onto the thus pretreated metal material of the cooling section. During the injection molding process, the plastic material can penetrate into the cavities. Such a connection between the two materials is therefore extremely resilient and also liquid-tight. This reliably prevents any cooling fluid from escaping at the connection point between the plastic material of the line section and the metal material of the cooling section.This eliminates the need for complex additional seals or mechanically complex processes such as crimping, welding, or soldering. A nanomold process directly bonds the plastic material of the line section and the metal material of the cooling section, without the need for additional connecting materials. The nanomold process therefore represents a particularly simple way to connect the line section to the cooling section.

[0011] Furthermore, in a cooling device according to the invention for a battery unit, it can be provided that the at least one line section has at least one supply line section and at least one separate discharge section, wherein the at least one supply line section, the cooling section, and the at least one discharge section are connected to one another in a fluid-communicating manner such that the cooling fluid can flow through the at least one supply line section, the cooling section, and the at least one discharge section one after the other in a flow direction of the cooling fluid. By dividing the line section into a supply line section and a discharge section, both the inlet and the outlet of the cooling fluid can be formed by the line section. This can result in additional weight savings.Of course, it can be provided that both the supply section and the discharge section comprise a plastic material, in particular the same plastic material, which is bonded to the metal material of the cooling section using a nanomold process. All the advantages already described for such a connection naturally also apply to the multiple formation of such a connection between a plastic material and a metal material.

[0012] Furthermore, a cooling device according to the invention can be designed such that the metal material is a light metal, in particular aluminum. A light metal is particularly lightweight. This allows additional weight savings while maintaining the good thermal conduction properties of metal. Aluminum, in particular, is a particularly easy-to-process light metal that has, in particular, good thermal conductivity. Effective cooling or heating of a battery unit, which is temperature-stabilized by such a cooling device according to the invention, can thus be ensured while simultaneously maintaining a low weight and good processability of the cooling device.

[0013] Particularly preferably, in a cooling device according to the invention for a battery unit, the cooling section can be at least partially formed by at least one flat tube. Flat tubes are particularly simply constructed components that can be produced in large quantities and, in particular, cost-effectively. Due to their flat surface, a direct arrangement of such a cooling section formed by a flat tube on the battery unit is particularly easy. Such flat tubes can, for example, be 1 to 4 cm wide and 3 to 5 mm high. The length of the flat tube can be adapted to the size of the battery unit for which the cooling device is intended. Lengths of the flat tubes over 1 m are certainly possible. The cooling capacity of a cooling device according to the invention with flat tubes can be adjusted by a number and / or a spacing and / or a cross-section of the flat tubes used. For example,When a cooling device is developed for a battery unit, the cooling or heating requirements of the battery unit are often known in advance. For example, hybrid vehicles may require a high cooling capacity for the battery unit. In this case, the cooling device could, for example, have many flat tubes arranged closely together. In contrast, purely electric vehicles, for example, may require less cooling capacity for the battery unit. In such a case, fewer flat tubes with a greater distance between the flat tubes can be provided in the cooling device. Flat tubes therefore represent a particularly simple and variable way of adapting a cooling device according to the invention to the cooling requirements of the battery unit.

[0014] Furthermore, a cooling device according to the invention for a battery unit can be designed such that the cooling device has a support device for supporting at least the cooling section, wherein the support device in particular has a rib structure. In order to create a cooling device with the lowest possible weight, it can be advantageous to design the cooling section in particular to be as thin as possible. Thin in the sense of the invention means that the extension perpendicular to the contact surface of the cooling section with the battery unit has a small extent. In particular with the flat tubes mentioned above, this can mean, for example, that they have a width of several centimeters and a height of only a few millimeters.In particular, with an additional large longitudinal extension, which may be due to the requirements of the battery unit, mechanical instabilities of the cooling section can occur in this case. Providing a thin wall thickness of the cavity in the region of the cooling section can, on the one hand, increase the thermal coupling of the battery unit to the cooling fluid, but, on the other hand, also reduce the stability of the cooling section. This can be prevented by providing a support device. The support device can preferably be designed such that it at least imparts mechanical stability to the cooling section or at least improves this mechanical stability. This can particularly preferably be achieved by a rib structure of the support device.In particular, a rib structure can achieve the highest possible stability while simultaneously saving weight with regard to the support device, since unnecessary material can be saved in the support device.

[0015] According to a preferred further development of a cooling device according to the invention, it can be provided that the support device comprises a plastic material. Plastic materials are particularly lightweight while having high mechanical stability. By providing a plastic material for the support device, further weight can be saved in a cooling device according to the invention. This can, for example, be the same plastic material that was also used for the at least one line section. In particular, in this case it can be provided that the support device is connected to the metal material of the cooling section in the same work step as the line section. Additional work steps for connecting the support device to the rest of the cooling device are thus not possible. Fast and simple production of a cooling device according to the invention can thereby be achieved.Alternatively, the plastic material used for the support device can be different from the plastic material used for the at least one line section. In particular, an even lighter plastic can preferably be used, thereby enabling further weight savings.

[0016] According to a particularly preferred further development of a cooling device for a battery unit according to the invention, it can further be provided that the plastic material of the support device is a recycled plastic material. By using a recycled plastic material, an additional cost advantage can be achieved in addition to all the advantages already described above. Furthermore, the use of a recycled plastic material can also protect the environment.

[0017] In a second aspect of the invention, the object is achieved by a battery unit with a cooling device for a battery unit. In particular, the battery unit according to the invention can be provided with a cooling device designed according to the first aspect of the invention. All the advantages described for a cooling device according to the invention for a battery unit according to the first aspect of the invention thus naturally also apply to a battery unit according to the invention that has such a cooling device for a battery unit.

[0018] Furthermore, in a battery unit according to the invention, a contact means can be provided on the cooling device. The contact means can preferably be arranged on the surface of the cooling section facing the battery unit. Such a contact means can be, for example, a thermally conductive paste. By using such a contact means, the thermal coupling between the battery unit and the cooling fluid flowing in the cavity of the cooling device can be further improved. An exchange of thermal energy between the battery unit and the cooling fluid can thereby be improved. Operating a battery unit according to the invention in an ideal temperature range is thus possible even more efficiently.

[0019] According to a third aspect of the invention, the object is achieved by a method for producing a cooling device for a battery unit, the cooling device having a cavity through which a cooling fluid can flow, which cavity has at least one line section and at least one cooling section connected thereto in a fluid-communicating manner, wherein at least the cooling section can be brought into thermal contact with the battery unit, and wherein the line section comprises a plastic material and the cooling section comprises a metal material. In particular, the method according to the invention for producing a cooling device for a battery unit is characterized in that the plastic material of the line section and the metal material of the cooling section are bonded to one another using a nanomold process.

[0020] By using plastic materials for the line section, weight can be saved, particularly compared to a cooling device in which the cavity is completely defined by metal. By providing a metal material in the cooling section, a high cooling performance for the battery unit to be cooled or heated can still be ensured due to the high thermal conductivity of the metal material. A nanomold process, in which the metal material is subjected to a special surface treatment before the plastic material is injected, represents a particularly simple method for creating a particularly good connection between the line section and the cooling section of the cooling device. In the special surface treatment of the metal material, the surface of the metal material is treated such that it has a certain porosity with cavities in the sub-micrometer range.During injection molding, the plastic material of the line section can penetrate into these cavities. This allows a particularly good connection between the plastic material of the line section and the metal material of the cooling section. Additional seals or complex joining processes such as soldering, welding or crimping can be avoided. A method according to the invention for producing a cooling device for a battery unit is particularly preferably used to produce a cooling device for a battery unit according to the first aspect of the invention or a cooling device that can be used for a battery unit according to the second aspect of the invention. All the advantages that lead to a cooling device for a battery unit according to the first aspect of the invention orfor a battery unit according to the second aspect of the invention, in these cases there also arise, of course, a method for producing a cooling device for a battery unit, by means of which such a cooling device for a battery unit according to the first aspect of the invention or a cooling device usable for a battery unit according to the second aspect of the invention is produced. PREFERRED EMBODIMENTS

[0021] The cooling device for a battery unit according to the invention and its further developments and advantages, the battery unit according to the invention and its further developments and advantages, as well as the method according to the invention and its advantages, are explained in more detail below with reference to the drawings. They show schematically: Fig. 1 a first possible embodiment of a cooling device according to the invention with a battery unit in a first sectional view and Fig. 2 a further possible embodiment of a cooling device according to the invention in a second sectional view.

[0022] Elements with the same function and mode of action are listed in the Fig. 1 and Fig. 2 are each provided with the same reference numerals.

[0023] Fig. 1 schematically shows a sectional view of a cooling device 1 according to the invention for a battery unit 20. The battery unit 20 is shown in thermal contact with the cooling section 7 of the cooling device 1. The cooling section 7 is formed by a flat tube 8. Together with the line section 4, which is formed by a supply line section 5 and a discharge section 6, the cooling section 7 forms a cavity 2 of the cooling device 1, through which a cooling fluid 3 can flow. The flow direction of the cooling fluid 3 is indicated by an arrow 11. A contact means 21, in particular a thermally conductive paste, is additionally arranged between the battery unit 20 and the surface of the flat tube 8. This contact means 21 further improves the thermal coupling between the cooling fluid 3 flowing in the cooling section 7 and the battery unit 20.To increase the mechanical stability of the cooling device 1, the cooling section 7 formed by the flat tube 8 is further supported by a support device 9. This support device 9 has a rib structure 10. Such a rib structure 10 enables, in particular, high mechanical stability while maintaining low weight. The support device 9 preferably comprises a plastic material, particularly preferably a recycled plastic material. A further weight reduction in a cooling device 1 according to the invention can be achieved by using a plastic material for the line section 4. Plastic materials are usually lighter than metal materials, but in most cases also have lower thermal conductivity.By using metal materials with high thermal conductivity for the cooling section 7 and simultaneously using plastic materials for the line section 4, which is formed by a supply line section 5 and a discharge section 6 and for which high thermal conductivity is not important, a cooling device 1 can be provided that is lightweight while simultaneously providing high cooling or heating performance. According to the invention, the plastic material of the line section 4 and the metal material of the cooling section 7 are connected to one another using a nanomold process. Such a nanomold process enables a particularly strong connection between these two materials while simultaneously ensuring impermeability to the cooling fluid 3. Additional seals or more mechanically complex processes for connecting the two sections 4, 7 can thus be avoided.A cooling device 1 according to the invention is thus, on the one hand, particularly lightweight while simultaneously having a high thermal energy transfer capacity and, on the other hand, particularly simple to manufacture.

[0024] In Fig.Figure 2 shows a second sectional view of a further embodiment of a cooling device 1 according to the invention. The cavity 2 through which the cooling fluid 3 can flow is formed here by a supply line section 5, a discharge section 6, the two together forming the line section 4, and a plurality of cooling sections 7 formed by flat tubes 8. The flow direction 11 of the cooling fluid 3 is indicated by three arrows. Naturally, the cooling fluid 3 flows through all of the cooling sections 7, although only one of the cooling sections 7 is marked with a flow direction 11. Between each of the cooling sections 7, a support device 9 is visible, which improves the mechanical stability of the cooling device. It is clearly visible that the width of the flat tubes 8 and their distances from one another are different.This allows for the thermal requirements of the battery unit 20 (not shown) to be taken into account. In areas of the battery unit 20 where, for example, strong cooling is required, wider flat tubes 8 are used; in other areas requiring less cooling, narrower flat tubes 8 are used. This allows for particularly simple adaptation to the cooling requirements of a battery unit 20.

Claims

[1] Method for producing a cooling device (1) for a battery unit (20), the cooling device (1) having a cavity (2) through which a cooling fluid (3) can flow, which cavity has at least one line section (4) and at least one cooling section (7) connected thereto in a fluid-communicating manner, wherein at least the cooling section (7) can be brought into thermal contact with the battery unit (20) and wherein the line section (4) comprises a plastic material and the cooling section (7) comprises a metal material, characterized bythat the plastic material of the line section (4) and the metal material of the cooling section (7) are joined to one another by a nanomold process, wherein firstly the metal material is pretreated in such a way that a surface of the metal material has, at least in sections, a porous structure with cavities in the submicrometer range, and then the plastic material is injection-molded onto the pretreated metal material in such a way that plastic material penetrates into the cavities. [2] Cooling device (1) for a battery unit (20), with a cavity (2) through which a cooling fluid (3) can flow, which cavity has at least one line section (4) and at least one cooling section (7) connected thereto in a fluid-communicating manner, wherein at least the cooling section (7) can be brought into thermal contact with the battery unit (20) and wherein the line section (4) comprises a plastic material and the cooling section (7) comprises a metal material, wherein the plastic material of the line section (4) and the metal material of the cooling section (7) are connected to one another by a method according to claim 1, characterized byin that the at least one line section (4) has at least one supply line section (5) and at least one discharge section (6) separate therefrom, wherein the at least one supply line section (5), the cooling section (7) and the at least one discharge section (6) are connected to one another in a fluid-communicating manner such that the at least one supply line section (5), the cooling section (7) and the at least one discharge section (6) can be successively flowed through by the cooling fluid (3) in a flow direction (11) of the cooling fluid (3). [3] Cooling device (1) for a battery unit (20) according to claim 2, characterized by that the metal material is a light metal, in particular aluminum. [4] Cooling device (1) for a battery unit (20) according to one of the preceding claims 2 or 3, characterized by that the cooling section (7) is at least partially formed by at least one flat tube (8). [5] Cooling device (1) for a battery unit (20) according to one of the preceding claims 2 to 4, characterized by that the cooling device (1) has a support device (9) for supporting at least the cooling section (7), wherein in particular the support device (9) has a rib structure (10). [6] Cooling device (1) for a battery unit (20) according to claim 5, characterized by that the support device (9) comprises a plastic material. [7] Cooling device (1) for a battery unit (20) according to claim 6, characterized by that the plastic material of the support device (9) is a recycled plastic material. [8] Battery unit (20) with a cooling device (1) for a battery unit (20), characterized by that the cooling device (1) is designed according to one of the preceding claims 2 to 7. [9] Battery unit (20) according to claim 8, characterized bythat a contact means (21) is provided on the cooling device (1).

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