Cooling plate and method for producing a cooling plate

Abstract

The invention relates to a cooling plate (1) for a cooling battery of a motor vehicle, comprising a plate body (2) consisting of two plate parts (3, 4) which are joined to each other by brazing, at least one cooling channel (5) for conveying a cooling fluid, and a reinforcing profile (6). The cooling channel (5) and the reinforcing molding (6) are first formed continuously together during the production of the sheet metal body (2) in such a way that a channel is formed in the sheet metal parts (3, 4) by means of internal high-pressure molding. During the brazing process, the channel section (7) of the channel (11) is closed in a fluid-tight manner by a closing element (8) in the form of a pressure-welded fitting (9). Therefore, the channel (11) is divided into a cooling channel (5) and a reinforcing forming part (6).

Description

Technical Field

[0001] The invention relates to a cooling plate for cooling a battery, in particular for cooling a motor vehicle battery, and to a method for producing a cooling plate. Background Art

[0002] High-voltage battery systems are used in electric vehicles or hybrid vehicles. To ensure the range, driving power and charging power as well as the service life of electrically driven vehicles, clear thermal management of the battery is required. Batteries are sensitive to different temperature distributions, which can lead to overheating and premature aging. In order to keep the battery within the optimal temperature range, cooling devices are used, which ensure that the excess waste heat generated during battery operation is dissipated from the battery and that the battery is kept at a uniform temperature level.

[0003] In order to cool the battery or battery module, cooling plates are used, which are arranged above, to the side and / or below the battery and are in direct or indirect contact with the battery. A cooling fluid flows through the cooling plates. Such cooling plates usually consist of two plate parts, which are combined to form a plate body and define one or more intermediate cooling channels. Usually, the cooling plates are made of light metal plates, in particular aluminum plates.

[0004] DE 10 2008 059 955 B4 discloses a cooling plate and a method for producing a cooling plate with integrated cooling channels, which belong to the prior art. The cooling plate has a plate body consisting of two plate parts, which has a connection for a cooling fluid. The cooling channels are formed in the plate parts of the cooling plate by a non-chip forming technology. The plate part provided with the cooling channels is closed by a second planar plate part.

[0005] Cooling plates of similar design are known from DE 10 2011 106 662 A1 and DE 10 2011 107 607 A1, in which the cooling plate or its plate body is provided with reinforcements in the form of rigid profiles or coolant-free cavities, thereby achieving additional reinforcement of the cooling plate. Summary of the invention

[0006] Based on the prior art, the object of the present invention is to provide a cooling plate which is improved in terms of function and production technology and to provide a rational method for producing a cooling plate.

[0007] This object is substantially achieved by a cooling plate according to the features of claim 1 .

[0008] This object is achieved in part with regard to the method by a method as claimed in claim 6 .

[0009] Advantageous design embodiments and developments of the invention are the subject matter of the dependent claims.

[0010] The cooling plate has a plate body consisting of two plate parts. The cooling fluid is input and output through a connecting pipe joint. The connecting pipe joint is connected to the plate body or its plate parts in a material-locked manner. In particular, the plate part is a channel plate and a base plate, which are combined into a plate stack and connected to each other to form the plate body. The plate parts are composed of light metal or light metal alloy, in particular, aluminum alloy. At least one plate part of the plate body of the cooling plate has a channel structure for conveying the cooling fluid. The plate parts are connected in a material-locked manner by pressure welding (pressure brazing). The brazing process is implemented in a forming brazing mold. For this purpose, a plate stack consisting of two plate parts is clamped in a forming brazing mold, pressed against each other and heated to a temperature above the melting temperature of the brazing material applied between the plate parts, so that the brazing material melts and transforms into a liquid phase, and after the brazing material solidifies, the plate parts are connected in a material-locked manner on the joint surfaces that are abutted against each other.

[0011] In order to form one or more channels in at least one of the sheet metal parts, the sheet metal parts are clamped in a forming brazing die and an internal pressure is applied to the intermediate space between the sheet metal parts. For this purpose, an active medium is introduced into the intermediate space and a channel structure with at least one channel or a plurality of channels is generated by internal high pressure technology.

[0012] The cooling plate for cooling a battery of the present invention has a plate body, which is composed of two plate parts joined to each other by brazing technology. The plate body has a channel structure with at least one cooling channel for conveying a cooling fluid and a reinforcement molding. The reinforcement molding is used to reinforce the plate body and improve the shape stability of the cooling plate. High shape stability ensures good contact between the cooling plate and the battery module. This is beneficial to thermal management. The high shape stability of the cooling plate also has a positive effect during collision loads and during handling during the assembly process of the battery assembly and the cooling system.

[0013] According to the invention, the channel section between the cooling channel and the reinforcement profile is closed in a fluid-tight manner by the closing element.

[0014] The reinforcement profile is preferably formed by a groove-shaped or corrugated profile in at least one plate. The reinforcement profile is formed together with the cooling channel during the molding process by internal high pressure technology. The channel formed between the plate members is divided into a cooling channel and a reinforcement profile by the closing element. In this way, a cooling plate that is improved in terms of function and manufacturing technology is provided. The production of the cooling plate, in particular the production of the reinforcement structure with the reinforcement profile in the cooling plate, is reasonable, economical and saves structural space. The high shape stability of the cooling plate is ensured by the reinforcement profile forming the reinforcement structure, in particular the arrangement and geometry of a plurality of reinforcement profiles, and the high rigidity that is adapted to the weight of the battery or battery module and the loads and forces generated during driving is ensured.

[0015] The reinforcement profile is not traversed by the coolant. The coolant flow is separated in a fluid-tight manner by the closing element. Advantageously, one or more openings are provided in the reinforcement profile. In this case, the openings are functional holes which are used to ventilate the reinforcement profile or for fastening, for example, for connecting the cooling plate to the base plate.

[0016] The method for producing a cooling plate comprises the following steps:

[0017] - providing a plate stack consisting of at least two plate elements made of a metallic material and a brazing material arranged between the plate elements;

[0018] - placing the sheet stack into a heated forming brazing mold having a lower mold and an upper mold;

[0019] - closing the forming mould, wherein the lower mould and the upper mould are moved towards each other;

[0020] - Close the forming brazing mold and clamp the plate stack between the lower and upper molds;

[0021] - heating the plate stack;

[0022] - by introducing an active medium into the intermediate space between the plates of the plate stack, an internal pressure is exerted on the intermediate space and a channel is formed in at least one of the plates;

[0023] - melting the brazing material between the plates and joining the plates at the abutting joint surfaces by brazing technology;

[0024] - a closing element is formed therein, by which the channel is divided into a cooling channel and a reinforcement profile;

[0025] - Open the forming brazing mold and remove the cooling plate from the forming brazing mold.

[0026] The closing element is produced by pressure welding the joint during the brazing process. In this case, the closing element is formed in a channel section of the channel produced by internal high pressure technology. A plurality of reinforcement profiles can be produced. Thus, a plurality of channel sections are each closed by a closing element, so that each reinforcement profile is separated from the cooling channel.

[0027] The cooling channel and the reinforcement profile are connected to each other by a channel segment before being separated in a fluid-tight manner. The channel segment is a component of the channel formed by the hydroforming technology. The channel segment can be designed to be smaller in geometry than the cooling channel and / or the reinforcement profile. In particular, the channel segment can have a smaller cross section than the cooling channel or the reinforcement profile. The channel segment is closed in a fluid-tight manner by a closing element.

[0028] Preferably, openings are made in the reinforcement profile so that the reinforcement profile is ventilated. The openings can be made in the forming brazing mold. Preferably, one or more openings are made in the reinforcement profile outside the forming brazing mold after the cooling plate is made.

[0029] The forming brazing mold is heated to a mold temperature at which the internal high pressure forming process and the brazing joining process are performed, in particular, the mold temperature is between 540°C and 670°C, and in particular, the mold temperature is between 550°C and 640°C.

[0030] A plurality of reinforcement profiles, in particular reinforcement corrugations, particularly advantageously extend parallel to a cooling channel, a cooling channel section, a cooling channel structure or a plurality of cooling channels.

[0031] When producing a brazed connection between sheet metal parts, the channel section is closed during the brazing process by a punch pressing it in a profile brazing die, so that it is also brazed. This provides a reinforcement profile that is separated from the cooling channel and has a cavity, which is not traversed by cooling fluid during operation but increases the rigidity of the component.

[0032] An advantageous design of the method according to the invention provides that the closing process of the profile brazing mold is interrupted before the closing position is reached. The upper mold and the lower mold are positioned at a distance from each other in this holding position when the sheet metal stack is inserted. This holding position is maintained for a holding time. In this case, the sheet metal stack resting on the lower mold is heated. After the holding time, the mold closing movement (closing movement) is continued, the profile brazing mold is closed, and the sheet metal stack is clamped between the lower mold and the upper mold. While clamped in the profile brazing mold, the sheet metal stack is further heated to the brazing temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention is explained in detail below with reference to the accompanying drawings.

[0034] Figure 1 A perspective view of a cooling plate of the present invention is shown. DETAILED DESCRIPTION

[0035] The cooling plate 1 is used to cool a battery, in particular an onboard battery of a motor vehicle.

[0036] The cooling plate 1 has a plate body 2 which is composed of two plate parts 3, 4. The plate part 3 which is located at the front in the drawing plane is a channel plate which has a channel structure with at least one cooling channel 5. The rear plate part 4 shown in the figure is a generally completely or almost completely flat base plate.

[0037] The two plate parts 3, 4 are positioned in a planar manner and overlap each other to form the plate body 2. The mutually abutting surfaces of the plate parts 3, 4 are completely or partially provided with soldering material. In particular, the soldering material is pre-applied on one of the plate parts 3, 4 in the form of an electroplated solder layer.

[0038] The surfaces of the plates 3 , 4 that abut against one another are joined to one another completely or partially. Figure 1 A connecting pipe joint for cooling fluid, not shown in the figure, is connected to the plate body 2. The connecting pipe joint is used for inputting and outputting cooling fluid.

[0039] The plate body 2 has a reinforcement structure with a reinforcement profile, preferably a plurality of reinforcement profiles 6. The reinforcement profile 6 is designed in particular in the form of reinforcement corrugations. The reinforcement profile 6 and the cooling channel 5 are initially connected to each other via a channel section 7. The channel section 7 between the cooling channel 5 and the reinforcement profile 6 is closed in a fluid-tight manner by a closing element 8. The closing element 8 is formed by a compression welded joint 9.

[0040] One or more openings 10 are provided in the reinforcement profile 6. The openings 10 are used for ventilation of the reinforcement profile 6 or for fastening to or with a functional component, and are formed after the cooling plate 1 or the plate body 2 is manufactured.

[0041] The cooling channel 5 , the reinforcement profile 6 , the channel section 7 and the closing element 8 which closes the channel section 7 in a fluid-tight manner are produced during the production of the cooling plate 1 or the plate body 2 .

[0042] To produce the cooling plate 1, a laminated plate stack is provided consisting of at least two initially flat sheet metal parts 3, 4 made of an aluminum alloy. A brazing material is applied between the sheet metal parts 3, 4, wherein the brazing material is applied to at least one of the sheet metal parts 3, 4 in the form of an electroplated solder layer.

[0043] The sheet stack is placed in a heated forming brazing mold.

[0044] The profile brazing die has a lower die and an upper die. The lower die and the upper die move relative to each other during the closing movement of the profile brazing die. In particular, the upper die is lowered onto the lower die. In order to heat the plate stack, the closing movement is interrupted. The upper die and the lower die are kept at a small distance from each other. The distance is several centimeters. The plate stack rests loosely on the lower die and is preheated. After a heating phase, which can last for more than 5 seconds, preferably less than 1 minute, in particular between 10 and 30 seconds, the profile brazing die is completely closed by lowering the upper die onto the lower die. In this case, the plate stack is received and clamped between the lower die and the upper die. In this case, the plate stack is in surface contact between the lower die and the upper die and is further heated in the profile brazing die. The profile brazing die is heated to a die temperature at which the forming process and the brazing joining process are carried out. In particular, the die temperature is between 540° C. and 670° C., and the die temperature is particularly advantageously between 550° C. and 640° C.

[0045] Internal pressure is applied to the intermediate space between the plates 3, 4 of the plate pack. The intermediate space is the area between the plates resting against each other, wherein no gaps between the plates are necessarily present in the area of ​​the intermediate space. The intermediate space is subjected to internal pressure by introducing an active medium, in particular nitrogen, into the intermediate space. In this case, the channel 11 is formed by deforming / molding at least one plate area into a channel cavity in one or more contact surfaces of the profile brazing die using internal pressure technology. The active medium is preferably introduced via one of the connecting pipe connections of the plate pack or an external interface adapter.

[0046] The brazing material between the sheet metal parts 3 and 4 melts due to the mold temperature of the forming brazing mold. The sheet metal parts 3 and 4 are joined together with each other and the connecting pipe joints positioned in a suitable manner by brazing technology.

[0047] When making the pressure-welded joint of the sheet metal parts 3 and 4, the channel section 7 of the channel 11 is closed by a closing element 8 in the form of a pressure-welded joint 9. Therefore, the channel 11 formed continuously by the internal high-pressure technology is divided into a cooling channel 5 and a reinforcement profile 6. During the internal high-pressure forming process, the cooling channel 5 and the reinforcement profile 6 are connected to each other via the channel section 7. During the brazing process, these connections or channel sections 7 are closed by the closing element 8. For this purpose, a pressure-welded joint 9 is formed in the channel section 7 in the following way, that is, a punch in the forming brazing die presses the channel section 7, thereby also brazing the channel section. In this way, the cooling channel 5 is formed, which is determined and arranged for conveying a cooling fluid. In addition, a plurality of reinforcement profiles 6 are formed, through which the cooling fluid does not flow during operation. The reinforcement profile 6 improves the shape stability and component rigidity.

[0048] After the forming brazing process is completed, the forming brazing mold is opened, wherein the lower mold and the upper mold are moved relative to each other and separated from each other. After the forming brazing mold is opened, the joined hot plate body 2 or the cooling plate 1 can be taken out of the forming brazing mold. Before being taken out, the cooling plate 1 can be kept in the forming brazing mold and cooled. Preferably, it is cooled to a temperature below the melting point of the brazing material.

[0049] During the manufacture of the cooling plate, the plate stack is clamped between the lower die and the upper die. When the channel 11 is formed and formed by internal pressure and the channel 11 is divided into the cooling channel 5 and the reinforcement profile 6 (especially the reinforcement fold) in a fluid-tight manner, the plate stack is sealed around the edge area that is in contact with each other and / or adjacent to the channel cavity. The sealing can be achieved or assisted by a pressure element arranged in the lower die and / or the upper die. Such a pressure element is optional and can also be arranged in the area of ​​the connecting pipe joint. The pressure element can be formed by a corresponding contour in the profiled part of the lower die and / or the upper die, for example by a sealing fold. The sealing element can be arranged around the edge area of ​​the upper die and / or the lower die that is in contact with each other. The sealing element can also be arranged adjacent to the channel cavity. The sealing element ensures a particularly advantageous forming process, especially that the forming process is carried out in the area of ​​the channel cavity. In this way, high dimensional accuracy and forming accuracy are ensured.

[0050] Reference numerals list

[0051] 1 Cooling plate

[0052] 2 board body

[0053] 3 Panels

[0054] 4 Panels

[0055] 5 Cooling channels

[0056] 6 Reinforcement molding part

[0057] 7 Channel Section

[0058] 8 Closure element

[0059] 9 Press-weld parts

[0060] 10. Opening

[0061] 11 channels

Claims

1. A cooling plate (1) for cooling a battery, the cooling plate comprising a plate body (2), the plate body consisting of two plate parts (3, 4) joined to each other by means of a brazing technique and having at least one cooling channel (5) for conveying a cooling fluid and having a reinforcement profile (6), characterized in that: The channel section (7) between the cooling channel (5) and the reinforcement profile (6) is closed in a fluid-tight manner by a closing element (8).

2. The cooling plate according to claim 1, characterized in that: The closing element (8) is formed by a joint, in particular a press-welded joint (9).

3. The cooling plate according to claim 1 or 2, characterized in that: The reinforcing profile (6) is formed by a groove-shaped or corrugated profile in at least one of the sheet metal parts (3, 4).

4. The cooling plate according to any one of claims 1 to 3, characterized in that: The reinforcement profile (6) has an opening (10).

5. The cooling plate according to any one of claims 1 to 4, characterized in that: The cooling channel (5) and the reinforcement profile (6) are formed by internal high pressure technology.

6. A method for producing a cooling plate (1), It is characterized by the following steps: - providing a plate stack consisting of at least two plate elements (3, 4) made of a metallic material and a brazing material arranged between the plate elements (3, 4); - placing the sheet stack into a heated forming brazing mold having a lower mold and an upper mold; - closing the forming mould, wherein the lower mould and the upper mould are moved towards each other; - closing the forming brazing die and clamping the plate stack between the lower die and the upper die; - heating the plate stack; - by introducing an active medium into the intermediate space between the plates (3, 4) of the plate stack, an internal pressure is exerted on the intermediate space, and a channel (11) is formed in at least one of the plates (3, 4); - melting the brazing material between the plate parts (3, 4) and joining the plate parts (3, 4) at the mutually abutting joint surfaces by means of a brazing technique; - a closing element (8) is formed therein, by which the channel (11) is divided into a cooling channel (5) and a reinforcement profile (6); - Open the mold for forming brazing and remove the cooling plate (1) from the mold for forming brazing.

7. The method according to claim 6, characterized in that: The closing element (8) is produced by pressure welding the joint (9) during the soldering process.

8. The method according to claim 6 or 7, characterized in that: The closure element (8) is formed in the channel section (7) of the channel (11).

9. The method according to any one of claims 6 to 8, characterized in that: An opening (10) is formed in the reinforcement profile (6).

10. The method according to any one of claims 6 to 9, characterized in that: The forming brazing mold is heated to a mold temperature between 540°C and 670°C, in particular to a mold temperature between 550°C and 640°C.

11. The method according to any one of claims 6 to 10, characterized in that: Before reaching the closed position, the closing process of the profile brazing die is interrupted for a holding time, wherein the upper die and the lower die are positioned at a distance from each other when the sheet metal stack is inserted, and after this holding time the profile brazing die is closed and the sheet metal stack is clamped between the lower die and the upper die.

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