Cooling plate and method for manufacturing a cooling plate

Abstract

A cooling plate 1 for cooling the battery of a motor vehicle has a plate body 2 consisting of two plate elements 3, 4 joined by soldering, and at least one cooling channel 5 for conveying a cooling fluid, as well as a stiffening element 6. During the manufacture of the plate body 2, the cooling channel 5 and the stiffening element 6 are initially formed together as a continuous channel by forming a channel in one of the plate elements 3, 4 through internal high-pressure forming. In the soldering process, a channel section 7 of the channel 11 is sealed fluid-tight by a sealing element 8 in the form of a press-solder joint 9. This separates the channel 11 into a cooling channel 5 and a stiffening element 6.

Description

[0001] The invention relates to a cooling plate for battery cooling, in particular for cooling a battery of motor vehicles, and a method for producing cooling plates.

[0002] High-voltage battery systems are used in electric or hybrid vehicles. To ensure the range, performance, and charging capacity, as well as the service life of electrically powered vehicles, defined thermal management of the batteries is required. Batteries are sensitive to varying temperature distributions, which can lead to overheating and premature aging. To keep the batteries within an optimal temperature range, cooling devices are used to ensure that excess heat generated during battery operation is dissipated from the batteries and the batteries are maintained at a uniform temperature level.

[0003] To cool batteries or battery modules, cooling plates are used. These plates are arranged above, to the side, and / or below the batteries and contact them directly or indirectly. A cooling fluid flows through the cooling plates. Such cooling plates typically consist of two plate elements that, when assembled to form a plate body, define one or more intermediate cooling channels. The cooling plates are typically made of light metal sheets, especially aluminum sheets.

[0004] DE 10 2008 059 955 B4 discloses a cooling plate and a method for producing a cooling plate with an integrated cooling channel. The cooling plate comprises a plate body formed from two plate elements with connections for a cooling fluid. A cooling channel is formed in one plate element of the cooling plate using a non-cutting forming technique. The plate element provided with the cooling channel is closed by the second flat plate element.

[0005] Comparably constructed cooling plates are described in DE 10 2011 106 662 A1 and DE 10 2011 107 607 A1. There, the cooling plates or their plate bodies are provided with stiffening elements in the form of stiffening protrusions or coolant-free cavities. This provides additional stiffening of the cooling plates.

[0006] Based on the prior art, the invention is based on the object of creating a cooling plate that is improved in terms of functionality and manufacturing technology, as well as demonstrating a rational method for producing a cooling plate.

[0007] The solution to the objective part of the problem consists in a cooling plate according to the features of claim 1.

[0008] The procedural part of the problem is solved by a method of claim 6.

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

[0010] A cooling plate comprises a plate body formed from two plate elements. A cooling fluid is supplied and discharged via connecting pieces. The connecting pieces are integrally joined to the plate body or its plate elements. The plate elements are, in particular, a channel plate and a base plate, which are combined to form a plate stack and, when joined together, form the plate body. The plate elements are made of light metal or a light metal alloy, in particular an aluminum alloy. At least one plate element of the plate body of the cooling plate has a channel structure for the passage of a cooling fluid. The plate elements are integrally joined by means of pressure soldering. The soldering process is carried out in a form soldering tool.For this purpose, a plate stack formed from the two plate elements is clamped in the form soldering tool, pressed together and heated to a temperature above the melting temperature of the solder material applied between the plate elements, so that the solder material melts into a liquid phase and, after the solder material has solidified, a material-to-material connection between the plate elements is created at the adjacent joining surfaces.

[0011] To form one or more channels in at least one of the plate elements, the plate elements are clamped in the brazing tool, and a gap between the plate elements is subjected to internal pressure. For this purpose, an active medium is introduced into the gap, and a channel structure with at least one or more channels is created using internal high-pressure technology.

[0012] A cooling plate for battery cooling according to the invention has a plate body formed from two plate elements joined together by soldering. The plate body has a channel structure with at least one cooling channel for conducting a cooling fluid and at least one stiffening formation. The stiffening formation serves to stiffen the plate body and improves the dimensional stability of the cooling plate. High dimensional stability ensures good contact between the cooling plate and the battery modules. This is advantageous for thermal management. High dimensional stability of the cooling plates also has a positive effect under crash loads, as well as during handling during the assembly process of the battery assembly and the cooling system.

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

[0014] The stiffening formation is preferably formed by a groove- or bead-shaped formation in at least one plate element. The stiffening formation is produced together with the cooling channel during the internal high-pressure forming process. The closure element separates the channel formed between the plate elements into a cooling channel and a stiffening formation. In this way, a cooling plate is created that is improved in terms of function and production technology. The production of the cooling plates and in particular of the stiffening structures with the stiffening formations in the cooling plate is efficient, cost-effective and saves space. The arrangement and geometry of the stiffening formation, in particular of several stiffening formations that form a stiffening structure, ensures high dimensional stability of the cooling plate with a high level of rigidity appropriate to the component compared to the weight of the battery orthe battery modules as well as the loads and forces that occur during driving.

[0015] Coolant does not flow through the stiffening formations. The coolant flow is sealed off in a fluid-tight manner by the closure element. Advantageously, one or more openings are provided in a stiffening formation. These are functional openings through which the stiffening formations are ventilated or serve for fastening purposes, for example, for connecting the cooling plate to a base plate.

[0016] A method for manufacturing a cooling plate comprises the following steps: - Providing a plate stack which is formed from at least two plate elements made of a metallic material with a solder material arranged between the plate elements; - Inserting the plate stack into a heated soldering tool, which has a lower tool and an upper tool; - Moving the forming tool, whereby the lower tool and the upper tool are moved relative to each other; - Closing the soldering tool and clamping the plate stack between the lower tool and the upper tool; - Heating the plate stack; - applying internal pressure to a space between the plate elements of the plate stack by introducing an active medium into the space and forming a channel in at least one plate element; - Melting of the solder material between the plate elements and soldering the plate elements together at the joining surfaces in the system; - wherein a closure element is created by which the channel is separated into a cooling channel and a stiffening formation; - Opening the soldering tool and removing the cooling plate from the soldering tool.

[0017] The closure element is created by a pressure brazing joint during the brazing process. The closure element is formed in a channel section of the internal high-pressure channel. Multiple stiffening formations can be created. Accordingly, several channel sections are each closed by a closure element, separating each stiffening formation from the cooling channel(s).

[0018] Before the cooling channel and the stiffening formation are separated in a fluid-tight manner, they are connected via the channel section. The channel section is a component of the hydroformed channel. The channel section can be geometrically smaller than a cooling channel and / or a stiffening formation. In particular, the channel section can have a smaller cross-section than a cooling channel or a stiffening formation. The channel section is closed in a fluid-tight manner by the closure element.

[0019] Preferably, an opening is created in a stiffening formation so that it is ventilated. The opening can be created in the brazing tool. Preferably, one or more openings in a stiffening formation are created outside of the brazing tool following the cooling plate production.

[0020] The form-brazing tool is heated to the tool temperature at which both the internal high-pressure forming process and the brazing joining process are carried out. The tool temperature is typically between 540°C and 670°C, but it is particularly advantageous to have a tool temperature between 550°C and 640°C.

[0021] Particularly advantageously, several stiffening formations, in particular stiffening beads, extend parallel to a cooling channel, a cooling channel section, a cooling channel structure or several cooling channels.

[0022] When creating the solder joint between the plate elements, the channel section is closed during the soldering process by a stamp in the form soldering tool pressing the channel section shut, so that it is also soldered. This creates a stiffening formation with a hollow chamber separate from the cooling channel. This hollow chamber is not subjected to cooling fluid during operation but increases the component's rigidity.

[0023] An advantageous embodiment of the method according to the invention provides that the closing process of the preformed soldering tool is interrupted before reaching the closed position. With the plate stack inserted, the upper tool and the lower tool are positioned at a distance from one another in this holding position. The holding position is maintained for a holding time. During this time, the plate stack resting on the lower tool is heated. Following the holding time, the closing movement is continued, the preformed soldering tool is closed, and the plate stack is clamped between the lower tool and the upper tool. Clamped in the preformed soldering tool, the plate stack is further heated to soldering temperature.

[0024] The invention is described in more detail below with reference to a drawing. The Fig. 1 shows a cooling plate according to the invention in a perspective view.

[0025] A cooling plate 1 is used for battery cooling, in particular a vehicle battery of a motor vehicle.

[0026] The cooling plate 1 has a plate body 2 formed from two plate elements 3, 4. The front plate element 3 in the image plane is a channel plate having a channel structure with at least one cooling channel 5. The rear plate element 4, indicated in the figure, is a base plate that is usually completely or almost completely flat.

[0027] The two plate elements 3, 4 are positioned flat against one another and form the plate body 2. The adjacent surfaces of the plate elements 3, 4 are coated entirely or partially with a brazing material. In particular, a brazing material is pre-applied in the form of a plated brazing layer on one of the plate elements 3, 4.

[0028] The adjacent surfaces of the plate elements 3, 4 are joined together completely or partially. On the plate body 2, Fig. 1 connection piece (not shown) for a cooling fluid is connected. The connection pieces are used to supply and drain a cooling fluid.

[0029] The plate body 2 has a stiffening structure with one, preferably several, stiffening formations 6. A stiffening formation 6 is designed in particular in the form of a stiffening bead. A stiffening formation 6 and a cooling channel 5 were originally connected via a channel section 7. The channel section 7 between the cooling channel 5 and the stiffening formation 6 is sealed in a fluid-tight manner by a closure element 8. The closure element 8 is formed by a pressure-soldered joint 9.

[0030] One or more openings 10 are provided in a stiffening formation 6. The openings 10 serve to ventilate the stiffening formation 6 or to attach it to or with functional components and are created following the manufacture of the cooling plate 1 or the plate body 2.

[0031] The cooling channel 5, the stiffening formations 6, the channel sections 7 and the closure elements 8 which close a channel section 7 in a fluid-tight manner are produced during the production of a cooling plate 1 or the plate body 2.

[0032] To produce a cooling plate 1, a plate stack consisting of at least two initially flat plate elements 3, 4 made of an aluminum alloy is provided. A brazing material is applied between the plate elements 3, 4, the brazing material being applied in the form of a plated brazing layer to at least one of the plate elements 3, 4.

[0033] The plate stack is placed into a heated soldering tool.

[0034] The preform soldering tool has a lower tool and an upper tool. These are moved relative to one another during the closing movement of the preform soldering tool. In particular, the upper tool is lowered onto the lower tool. To heat the plate stack, the closing movement is interrupted. The upper tool and the lower tool are located a short distance apart from one another. The distance is a few centimeters. The plate stack rests loosely on the lower tool and is preheated. After this heating phase, which can last longer than 5 seconds and preferably less than 1 minute, in particular between 10 and 30 seconds, the preform soldering tool is completely closed by lowering the upper tool onto the lower tool. The plate stack is picked up and clamped between the lower tool and the upper tool.The plate stack comes into surface contact between the lower tool and the upper tool and is further heated in the brazing tool. The brazing tool is heated to a temperature at which both the forming process and the brazing joining process are carried out. The tool temperature is typically between 540°C and 670°C, but the tool temperature is particularly advantageous between 550°C and 640°C.

[0035] A gap between the plate elements 3, 4 of the plate stack is subjected to internal pressure. A gap is an area between adjacent plate elements, whereby a gap between plate elements does not necessarily have to be present in the area of ​​the gap. The gap is subjected to internal pressure by introducing an active medium, in particular nitrogen, into the gap. In this case, a channel 11 is formed by internal pressure deformation of at least one plate element area into a channel cavity in one or the contact surfaces of the form-soldering tool. The active medium is preferably supplied via one of the connection pieces of the plate stack or an external connection adapter.

[0036] The solder material between the plate elements 3 and 4 is melted due to the temperature of the form soldering tool. The plate elements 3 and 4 are joined to each other and to the correctly positioned connecting pieces using soldering technology.

[0037] During the press-soldering process, channel sections 7 of channel 11 are closed by a closure element 8 in the form of a press-soldered joint 9. This separates the continuously produced channel 11 using internal high-pressure technology into the cooling channel 5 and the stiffening formations 6. The cooling channel 5 and the stiffening formations 6 were connected via channel section 7 during internal high-pressure forming. These connections, or the channel sections 2, are closed by closure elements 8 during the soldering process. For this purpose, press-soldered joints 9 are created in the channel sections 7 by a punch in the form-soldering tool pressing the channel section 7 closed, so that it is also soldered. In this way, the cooling channel(s) 5 are created, which are intended and configured for the passage of a cooling fluid. Furthermore, several stiffening formations 6 are created, through which no cooling fluid flows during operation.The stiffening formations 6 increase the dimensional stability and component rigidity.

[0038] The preform soldering tool is opened after the preform soldering process is completed, with the lower tool and the upper tool being displaced relative to each other and moved apart. The joined, warm plate body 2 or the cooling plate 1 can be removed from the preform soldering tool after it has been opened. Before removal, the cooling plate 1 can be held in the preform soldering tool and cooled. Cooling preferably takes place below the melting temperature of the solder material.

[0039] The plate stack is clamped between the lower tool and the upper tool during production of the cooling plates. During the internal pressure forming and formation of the channel 11 and the fluid-tight separation of the channel 11 into a cooling channel 5 and stiffening formations 6, in particular a stiffening bead, the plate stack is sealed circumferentially along adjacent edge regions and / or adjacent to the channel cavity. The sealing can be effected or assisted by pressure elements provided in the lower tool and / or the upper tool. Such pressure elements are optional and can also be provided in the region of connection pieces. The pressure elements can be formed by appropriate contouring in the forming sections of the lower tool and / or the upper tool, for example by sealing beads. The sealing elements can be provided circumferentially along adjacent edge regions of the upper tool and / or the lower tool.The sealing elements can also be provided adjacent to the channel cavity. These sealing elements ensure a particularly advantageous forming process, in particular, that the forming process takes place in the area of ​​the channel cavity. This ensures high dimensional stability and forming accuracy. Reference symbol: 1 cooling plate 2 plate bodies 3 plate element 4 plate element 5 cooling channel 6 Stiffening molding 7 Canal section 8 locking element 9 Press solder joint 10 Opening 11 Channel QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2008 059 955 B4

[0004] DE 10 2011 106 662 A1

[0005] DE 10 2011 107 607 A1

[0005]

Claims

[1] Cooling plate (1) for battery cooling with a plate body (2) which is formed from two plate elements (3, 4) joined together by soldering and has at least one cooling channel (5) for the passage of a cooling fluid and a stiffening formation (6), characterized by that a channel section (7) between the cooling channel (5) and the stiffening formation (6) is closed in a fluid-tight manner by a closure element (8). [2] Cooling plate according to claim 1, characterized by that the closure element (8) is formed by a joint, in particular a press-soldered joint (9). [3] Cooling plate according to claim 1 or 2, characterized by that the stiffening formation (6) is formed by a groove- or bead-shaped formation in at least one plate element (3, 4). [4] Cooling plate according to one of claims 1 to 3, characterized by that the stiffening formation (6) has an opening (10). [5] Cooling plate according to one of claims 1 to 4, characterized by that the cooling channel (5) and the stiffening formation (6) are designed using internal high-pressure technology. [6] Method for producing a cooling plate (1), characterized by following steps: - Providing a plate stack which is formed from at least two plate elements (3, 4) made of a metallic material with a solder material arranged between the plate elements (3, 4); - Inserting the plate stack into a heated soldering tool, which has a lower tool and an upper tool; - Moving the forming tool, whereby the lower tool and the upper tool are moved relative to each other; - Closing the soldering tool and clamping the plate stack between the lower tool and the upper tool; - Heating the plate stack; - applying internal pressure to an intermediate space between the plate elements (3, 4) of the plate stack by introducing an active medium into the intermediate space and forming a channel (11) in at least one plate element (3, 4); - melting the solder material between the plate elements (3, 4) and soldering the plate elements (3, 4) together at the joining surfaces; - wherein a closure element (8) is produced, by which the channel (11) is separated into a cooling channel (5) and a stiffening formation (6); - Open the soldering tool and remove the cooling plate (1) from the soldering tool. [7] Method according to claim 6, characterized by that the closure element (8) is produced by a press solder joint (9) in the soldering process. [8] Method according to claim 6 or 7, characterized by that the closure element (8) is formed in a channel section (7) of the channel (11). [9] Method according to one of claims 6 to 8, characterized by that an opening (10) is created in the stiffening formation (6). [10] Method according to one of claims 6 to 9, characterized by that the form soldering tool is heated to a tool temperature between 540 °C and 670 °C, in particular between 550 °C and 640 °C. [11] Method according to one of claims 6 to 10, characterized by that the closing process of the form soldering tool is interrupted for a holding time before reaching the closing position, whereby the upper tool and the lower tool are positioned at a distance from one another with the plate stack inserted and after the holding time the form soldering tool is closed and the plate stack is clamped between the lower tool and the upper tool.

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