Cooling plate and method of manufacturing cooling plate

Abstract

To provide a cooling plate improved in terms of functionality and production technology, and a rational method for producing the cooling plate.SOLUTION: A cooling plate 1 for the battery cooling of a motor vehicle comprises: one plate body 2 including two plate elements 3, 4 joined together by soldering, at least one cooling channel 5 for the passage of a cooling fluid, and one stiffening molding 6. The cooling channel 5 and the stiffening molding 6 are initially formed together continuously during the manufacture of the plate body 2 by forming a channel in a plate element 3, 4 by internal high pressure forming. In the soldering process, a channel portion 7 of the channel 11 is sealed in a fluid-tight manner by a closing element 8 in the form of a press soldering joint 9. This separates the channel 11 into the cooling channel 5 and the stiffening molding 6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling plate for cooling a battery, in particular for cooling a battery of a motor vehicle, and a method for manufacturing the cooling plate.

Background Art

[0002] In electric or hybrid motor vehicles, high-voltage battery systems are used. In order to ensure the driving range, driving performance, charging performance and service life of an electrically driven vehicle, a predetermined thermal management of the battery is necessary. The battery is sensitive to different temperature distributions, which can cause overheating and premature deterioration. To keep the battery within an optimal temperature range, a cooling device is used that discharges excess waste heat generated during operation of the battery from the battery and ensures that the battery is temperature-controlled to a uniform temperature level.

[0003] To cool a battery or battery module, a cooling plate is used that is arranged above, beside and / or below the battery and directly or indirectly contacts the battery or battery module. A cooling fluid flows through the cooling plate. Such a cooling plate usually consists of a plate body assembled from two plate elements that define one or more cooling channels therebetween. Usually, the cooling plate is manufactured from a light metal sheet, in particular an aluminum sheet.

[0004] According to German Patent Specification No. 102008059955, a method for manufacturing a cooling plate in which the cooling plate and the cooling channels are integrated is part of the prior art. The cooling plate comprises a plate body composed of two plate elements having connections for a cooling fluid. In one of the plate elements of the cooling plate, the cooling channels are formed by a non-cutting forming technique. The plate element provided with the cooling channels is closed by a second flat plate element.

[0005] Cooling plates configured in the same way are described in German Patent Application Publication No. 102011106662 and German Patent Application Publication No. 102011107607. In those cases, the cooling plate or its plate body has reinforcing elements in the form of rigid molded parts or cavities free of coolant. Thereby, additional reinforcement of the cooling plate is carried out.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Based on the prior art, the problem underlying the present invention is to provide a cooling plate that is improved both functionally and in terms of manufacturing technology, and to present a reasonable method for manufacturing the cooling plate.

Means for Solving the Problems

[0008] The solution to the physical part of the problem lies in the cooling plate according to the features of claim 1.

[0009] The solution to the method part of the problem is solved by the method according to claim 6.

[0010] Advantageous embodiments and developments of the present invention are the subject of the dependent claims.

[0011] The cooling plate comprises a plate body composed of two plate elements. The supply and discharge of the cooling fluid are carried out via a connecting pipe. The connecting pipe is materially joined to the plate body or its plate element. The plate elements are, in particular, a channel plate and a base plate integrated into a plate laminate and joined to each other to form the plate body. The plate elements are made of a 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 is provided with a channel structure for passing the cooling fluid. The plate elements are materially joined by press brazing. The brazing process is carried out in a forming brazing die. For this purpose, the plate laminate composed of both plate elements is clamped in the forming brazing die, pressed against each other, and heated to a temperature above the melting temperature of the brazing material applied between the plate elements. As a result, the brazing material changes to a liquid phase by melting, and after the solidification of the brazing material, a material bond of the plate elements occurs at the adjacent joint surfaces.

[0012] In order to form one or more channels in at least one of the plate elements, the plate elements are clamped in a forming brazing die, and the intermediate space between the plate elements is subjected to the action of internal pressure. For this purpose, a working medium is introduced into the intermediate space, and a channel structure having at least one channel or a plurality of channels is formed by internal high-pressure technology.

[0013] The cooling plate according to the present invention for battery cooling comprises a plate body composed of two plate elements joined to each other by brazing technology. The plate body is provided with at least one cooling channel for passing the cooling fluid and a channel structure having at least one reinforcing forming part. The reinforcing forming part is used to reinforce the plate body and improve the dimensional stability of the cooling plate. High dimensional stability ensures good contact between the cooling plate and the battery module. This is advantageous for thermal management. The high dimensional stability of the cooling plate acts positively both during the handling in the battery arrangement and the assembly process of the cooling system and during the action of a collision load.

[0014] According to the present invention, the channel portion between the cooling channel and the reinforcing molded portion is fluid-tightly closed by a closing element.

[0015] The reinforcing molded portion is preferably constituted by a groove-shaped or bead-shaped molded portion in at least one of the plate elements. The reinforcing molded portion is formed together with the cooling channel during molding by internal high pressure technology. By the closing element, the channel formed between the plate elements is separated from the cooling channel and the reinforcing molded portion. In this way, a cooling plate improved in terms of function and manufacturing technology is provided. The manufacture of the cooling plate, particularly of a reinforcing structure having a reinforcing molded portion in the cooling plate, is reasonable, economical, and space-saving. Due to the arrangement and geometry of the reinforcing molded portion, particularly of the plurality of reinforcing molded portions constituting the reinforcing structure, high dimensional stability of the cooling plate is ensured by a high rigidity suitable for the component with respect to the weight of the battery or battery module and the loads and acting forces generated during driving.

[0016] The coolant does not flow through the reinforcing molded portion. The coolant flow is fluid-tightly separated by the closing element. Advantageously, one or more openings are provided in the reinforcing molded portion. These are functional openings, and by these functional openings, the reinforcing molded portion is ventilated, or these functional openings are used for fixing, for example, for coupling the cooling plate to the base plate.

[0017] A method for manufacturing a cooling plate is - providing a plate laminate composed of at least two plate elements made of a metallic material with a brazing material disposed therebetween; - inserting the plate laminate into a heated molding and brazing mold having a lower mold and an upper mold; - closing the mold in which the lower mold and the upper mold are relatively moved with respect to each other; - closing the molding and brazing mold and clamping the plate laminate between the lower mold and the upper mold; - heating the plate laminate; - Introducing a working medium to apply internal pressure to the intermediate space between the plate elements of the plate stack, and forming channels in at least one of the plate elements; - Melting the solder between the plate elements and joining the plate elements by soldering technology at the contacting joint surfaces; - Forming a closing element that separates the channels into cooling channels and reinforcing molded parts; - Opening the molding soldering mold and removing the cooling plate from the molding soldering mold; It comprises.

[0018] The closing element is formed by a press soldering joint in the soldering process. Here, the closing element is formed within the channel portion of the channel formed by the internal high-pressure technology. A plurality of reinforcing molded parts can be formed. Accordingly, a plurality of channel portions are each closed by a closing element, whereby each one reinforcing molded part is separated from one or more cooling channels.

[0019] Before the fluid-tight separation of the cooling channels and the reinforcing molded parts, they are connected via a channel portion. The channel portion is part of the channel formed by hydroforming technology. The channel portion can be formed geometrically smaller than the cooling channels and / or the reinforcing molded parts. In particular, the channel portion can have a smaller cross-section than the cooling channels or the reinforcing molded parts. The channel portion is fluid-tightly closed by a closing element.

[0020] Preferably, an opening is formed in the reinforcing molded part, whereby the reinforcing molded part is vented. The opening can be formed within the molding soldering mold. Preferably, one or more openings within the reinforcing molded part are formed following the manufacture of the cooling plate outside the molding soldering mold.

[0021] The forming brazing die is heated to the die temperature when both the internal high-pressure forming process and the joining process by brazing technology are carried out. In particular, the die temperature is 540°C to 670°C, and particularly preferably, the die temperature is 550°C to 640°C.

[0022] Particularly preferably, a plurality of reinforcing forming parts, in particular reinforcing beads, extend parallel to one cooling channel, one cooling channel part, one cooling channel structure or a plurality of cooling channels.

[0023] When forming the brazed joint between the plate elements, the channel part is closed during the brazing process, in which the punch in the forming brazing die presses the channel part closed, whereby this channel part is also brazed. This provides a reinforcing forming part having a hollow chamber that is separated from the cooling channel and through which the cooling fluid does not flow during operation but increases the part rigidity.

[0024] An advantageous formation of the method according to the invention contemplates that the closing process of the forming brazing die is interrupted before reaching the closed position. The upper die and the lower die are positioned spaced apart from each other at this holding position when inserting the plate laminate. The holding position is held for a holding time. Here, the plate laminate located on the lower die is heated. After the holding time, the closing movement is continued, the forming brazing die is closed, and the plate laminate is clamped between the lower die and the upper die. Clamped within the forming brazing die, further heating of the plate laminate is carried out up to the brazing temperature.

[0025] The present invention will be described in detail below with reference to the drawings.

Brief Description of the Drawings

[0026]

Figure 1

Embodiments for Carrying Out the Invention

[0027] The cooling plate 1 is used for battery cooling, in particular for the vehicle battery of a motor vehicle.

[0028] The cooling plate 1 comprises a plate body 2 composed of 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 shown in the figure is usually a completely or almost completely flat base plate.

[0029] Both plate elements 3, 4 are positioned flat one above the other and form the plate body 2. The adjacent faces of the plate elements 3, 4 are provided with a brazing material either entirely or in regions. In particular, the brazing material is pre-applied to one of the plate elements 3, 4 in the form of a brazing layer.

[0030] The adjacent faces of the plate elements 3, 4 are joined to each other either entirely or in regions. A connecting pipe for the cooling fluid (not shown in FIG. 1) is connected to the plate body 2. The connecting pipe is used for supplying and discharging the cooling fluid.

[0031] The plate body 2 has a reinforcement structure with one, preferably a plurality of reinforcement moldings 6. The reinforcement moldings 6 are formed in particular in the form of reinforcement beads. The reinforcement layer 6 and the cooling channel 5 were initially connected via a channel portion 7. The channel portion 7 between the cooling channel 5 and the reinforcement molding 6 is fluid-tightly closed by a closing element 8. The closing element 8 is constituted by a press-brazed joint 9.

[0032] One or more openings 10 are provided in the reinforcement molding 6. The openings 10 are used for ventilation of the reinforcement molding 6 or for fixing to or with functional components and are formed after the manufacture of the cooling plate 1 or the plate body 2.

[0033] The cooling channel 5, the reinforcement molding 6, the channel portion 7 and the closing element 8 that fluid-tightly closes the channel portion 7 are formed during the manufacture of the cooling plate 1 or the plate body 2.

[0034] To manufacture the cooling plate 1, a plate laminate 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, and the brazing material is applied to at least one of the plate elements 3, 4 in the form of a plated brazing layer.

[0035] The plate laminate is inserted into a heated forming and brazing mold.

[0036] The forming and brazing mold comprises a lower mold and an upper mold. These molds are moved relative to each other during the closing movement of the forming and brazing mold. In particular, the upper mold is lowered onto the lower mold. To heat the plate laminate, the closing movement is interrupted. The upper mold and the lower mold are positioned at a small distance from each other. The distance is several centimeters. The plate laminate is movably positioned on the lower mold and preheated. After this heating stage, which can be longer than 5 seconds and preferably less than 1 minute, in particular 10 - 30 seconds, the forming and brazing mold is completely closed by lowering the upper mold onto the lower mold. The plate laminate is accommodated and clamped between the lower mold and the upper mold. The plate laminate is in surface contact between the lower mold and the upper mold and is further heated in the forming and brazing mold. The forming and brazing mold is heated to a mold temperature at which both the forming process and the joining process by brazing technology are carried out. In particular, the mold temperature is 54°C to 670°C, and particularly preferably, the mold temperature is 550°C to 640°C.

[0037] The intermediate space between the plate elements 3, 4 of the plate laminate is subjected to the action of internal pressure. The intermediate space is the region between adjacent plate elements, and it is not necessary for the gap between the plate elements to necessarily exist within the region of the intermediate space. The action of the internal pressure on the intermediate space is carried out by introducing a working medium, particularly nitrogen, into the intermediate space. Here, the channel 11 is formed by the internal pressure technique forming of at least one plate element region into the channel cavity within one or both contact surfaces of the molding brazing die. The supply of the working medium is preferably carried out via one of the connecting pipes of the plate laminate or an external connecting adapter.

[0038] The brazing material between the plate elements 3, 4 is melted due to the mold temperature of the molding brazing die. The plate elements 3, 4 and the connecting pipes positioned by joining are joined by the brazing technique.

[0039] When forming the brazed joint of the plate elements 3, 4 by the press brazing technique, the channel portion 7 of the channel 11 is closed by the closing element 8 in the form of the press brazed joint 9. Thereby, the channel 11 continuously formed by the internal high pressure technique is separated from the cooling channel 5 and the reinforcing molding part 6. Through the channel portion 7, the cooling channel 5 and the reinforcing molding part 6 were connected during the internal high pressure molding. These connections or channel portions 2 are closed by the closing element 8 during the brazing process. For this reason, the punch channel portion 7 in the molding brazing die is pushed and closed, and thereby, by also brazing this channel portion, the press brazed joint 9 is formed within the channel portion 7. In this way, one or more cooling channels 5 set and configured to allow the cooling fluid to pass through are provided. Further, a plurality of reinforcing molding parts 6 through which the cooling fluid does not flow during operation are provided. The reinforcing molding part 6 enhances the dimensional stability and component rigidity.

[0040] The forming brazing mold is opened after the completion of the forming brazing process, and the lower mold and the upper mold are moved relative to each other and separated. The joined high-temperature plate body 2 or the cooling plate 1 can be removed from the forming brazing mold after opening the forming brazing mold. Before removal, the cooling plate 1 can be held and cooled within the forming brazing mold. Cooling is preferably carried out until below the melting temperature of the brazing material.

[0041] The plate laminate is clamped between the lower mold and the upper mold during the manufacture of the cooling plate. During the forming and shaping by means of the internal pressure technique of the channel 11, and during the fluid-tight separation of the channel 11 into the cooling channel 5 and the reinforcing forming part 6, in particular the reinforcing bead, the plate laminate is sealed annularly along the adjacent peripheral regions and / or adjacent to the channel cavity. The sealing can be achieved or assisted by a pressurizing element provided in the lower mold and / or the upper mold. Such a pressurizing element is optional and can also be provided in the region of the connecting pipe. The pressurizing element can be formed, for example, by a sealing bead by means of a corresponding contour formation within the forming part of the lower mold and / or the upper mold. The sealing element can be provided annularly along the adjacent peripheral regions of the upper mold and / or the lower mold. The sealing element can also be provided adjacent to the channel cavity. The sealing element ensures a particularly advantageous forming process, especially that this forming process takes place in the region of the channel cavity. In this way, high dimensional accuracy and forming accuracy are ensured.

Explanation of reference numerals

[0042] 1 Cooling plate 2 Plate body 3 Plate element 4 Plate element 5 Cooling channel 6 Reinforcing forming part 7 Channel part 8 Closing element 9 Press brazing joint 10 Opening 11 Channel

Claims

1. A cooling plate (1) for cooling batteries, comprising a plate body (2) made of two plate elements (3, 4) joined together by brazing and equipped with at least one cooling channel (5) for passing a cooling fluid and one reinforcing molding (6), A cooling plate (1), characterized in that a channel portion (7) between the cooling channel (5) and the reinforcing molding (6) is closed in a fluid-tight manner by a closure element (8).

2. 2. The cooling plate according to claim 1, characterized in that the closure element (8) is constituted by a joint, in particular a press-brazed joint (9).

3. 3. A cooling plate according to claim 1 or 2, characterized in that the reinforcing features (6) are constituted by groove-like or bead-like features in at least one of the plate elements (3, 4).

4. A cooling plate according to any one of claims 1 to 3, characterized in that the reinforcing moulding (6) comprises an opening (10).

5. 5. The cooling plate according to claim 1, wherein the cooling channels (5) and the reinforcing mouldings (6) are formed by internal high pressure technology.

6. A method for manufacturing a cooling plate (1), comprising the steps of: - providing a plate stack consisting of at least two plate elements (3, 4) made of metallic material and having a brazing material arranged between them; - inserting the plate stack into a heated forming brazing mould comprising a lower mould and an upper mould; - closing the mould, moving the lower mould and the upper mould relative to each other; - closing the forming brazing mould and clamping the plate stack between the lower and upper moulds; - heating the plate stack, - applying an internal pressure to the intermediate spaces between the plate elements (3, 4) of the plate stack by introducing an acting medium to form channels (11) in at least one of the plate elements (3, 4); - melting the brazing material between the plate elements (3, 4) and joining the plate elements (3, 4) at their contacting joining surfaces by a brazing technique, - forming a closure element (8) by means of which the channel (11) is separated into a cooling channel (5) and a reinforcing moulding (6); - opening the molded brazing mold and removing the cooling plate (1) from the molded brazing mold; The method of claim 1, further comprising:

7. 7. The method according to claim 6, characterized in that the closure element (8) is formed by a press brazed joint (9) in a brazing process.

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

9. Method according to any one of claims 6 to 8, characterised in that openings (10) are formed in the reinforcing moulding (6).

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

11. 11. The method according to claim 6, characterized in that the closing process of the shaped brazing mould is interrupted for a holding time before reaching the closed position, the upper and lower moulds are positioned at a distance from each other when inserting the plate stack, and after the holding time the shaped brazing mould is closed and the plate stack is clamped between the lower and upper moulds.

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