Cooling plate, as well as a device with such a cooling plate

Abstract

Cooling plate, in particular a cooling plate of an electrical device, comprising - a heat-conducting plate (10), and - at least one cooling channel plate (11) with at least one cooling channel (29), - wherein at least one recess (12) is arranged between the heat-conducting plate (10) and the cooling channel plate (11), - wherein at least one cavity (15) containing a working fluid (16) is arranged in the at least one recess (12), which is aligned in a plane (17) parallel to the heat-conducting plate (10), - wherein at least one cavity (15) is sealed in a pressure-tight manner, and - wherein the cooling channel plate (11) is arranged completely within the recess (12).

Description

State of the art

[0001] The present invention relates to a cooling plate, in particular a cooling plate for power electronics, with an improved cooling effect and a device with at least one electrical component, preferably a power electronics component, with at least one cooling plate according to claim 1.

[0002] Cooling plates are known in various designs from the prior art. They are typically used in power electronics to cool power electronic components. A metallic substrate plate is usually located on the thermal path between the power electronic component and the cooling plate to distribute the heat from the component over a larger cross-sectional area by thermal spreading before it is transferred to the cooling plate, which then transfers the heat to a heat sink, such as a coolant circuit. The cooling plates have an enlarged surface area on the side facing the heat sink, which is provided, for example, with ribs or a multitude of protruding studs, also known as a pin-fin structure.

[0003] As electronic components, particularly power electronics, continue to evolve, ever-increasing power densities are achieved, which in turn lead to increased cooling requirements. The effectiveness of heat spreading via a substrate plate is limited; beyond a certain substrate area, the cooling effect cannot be further improved, and therefore conventional cooling plates no longer provide sufficient heat spreading or cooling for modern power electronics with the highest possible power density.

[0004] The JP S 63-38245 A reveals a cooling element based on the principle of a heat pipe in a closed system. Disclosure of the invention

[0005] In contrast, the cooling plate according to the invention with the features of claim 1 has the advantage that the conflict between low cost of a cooling plate, maximum cooling effect or heat dissipation with minimal size is resolved. The cooling plate according to the invention is thus intended to meet the requirements of power electronics components with the highest possible power density. This is achieved according to the invention by the cooling plate comprising at least one heat-conducting plate and at least one cooling channel plate with at least one cooling channel, wherein at least one recess is provided between the heat-conducting plate and the cooling channel plate, in which at least one pressure-tight cavity containing a working fluid is arranged, which is aligned in a plane parallel to the heat-conducting plate and wherein the cavity is pressure-tightly sealed.This ensures maximum heat transfer, allowing the heat dissipated from the power electronics component to be transferred to the largest possible cooling surface, specifically the cooling channel plate, thus maximizing cooling efficiency. The working fluid in the cavity distributes the heat emitted by the power electronics component across the surface of the cooling plate. The cavity is located within the cooling plate, between the heat-conducting plate and the cooling channel plate, and the working fluid is a refrigerant such as water, alcohol, ammonia, or a mixture of such refrigerants. This optimal cooling of the electrical component keeps the temperature of the power electronics component, such as an inverter for an electric vehicle drive, as low as possible, enabling the highest possible power densities. The recess is preferably formed within the heat-conducting plate.

[0006] Furthermore, the cooling channel plate is completely positioned within the recess. The depth of the recess is at least equal to the thickness of the cooling channel plate, so that the cooling channel plate can be completely accommodated within the recess, and a cavity is formed within the recess.

[0007] The dependent claims describe preferred embodiments of the invention.

[0008] Furthermore, it is particularly advantageous if the recess is integrated or molded into the heat-conducting plate. The recess is adapted to the shape of the cooling channel plate, so that the cooling channel plate can be inserted precisely into the recess to form the pressure-tight cavity, and the recess is sealed.

[0009] Preferably, the cooling channels of the cooling channel plate are designed with cooling fins and / or pin-fin structures on one side facing the heat sink, thereby increasing the surface area of ​​the cooling channel plate facing the heat sink. The cooling fins and / or the pin-fin structures can extend into a cooling medium, for example, a vehicle's cooling water system, thus ensuring particularly good heat dissipation and heat transport.

[0010] Furthermore, it is particularly advantageous if the cooling fins and / or the pin fin structure are arranged within the recess, resulting in a particularly compact design of the cooling plate. This offers particular advantages during storage, transport, or installation of the cooling plate, as the sensitive cooling fins and / or pin fin structures are protected within the recess and thus shielded from damage.

[0011] Preferably, the at least one cavity is designed as a heat pipe, a two-phase thermosiphon or as a vapor chamber, wherein the heat pipe, the two-phase thermosiphon and the vapor chamber have in common that the heat transport takes place through the working medium and a particularly high heat transfer can be achieved.

[0012] Preferably, the at least one heat pipe, two-phase thermosiphon, or vapor chamber is formed from the heat-conducting plate and / or the cooling channel plate in one or more parts. The heat-conducting plate and / or the cooling channel plate can have corresponding shapes on their respective facing sides to form the heat pipe, two-phase thermosiphon, or vapor chamber.

[0013] Preferably, the at least one cavity is formed partially from the heat-conducting plate and / or the cooling channel plate. The cavity can have differently designed surfaces on both the side facing the heat source and the side facing the heat sink, each corresponding to the heat-conducting plate and the cooling channel plate, respectively.

[0014] According to a further embodiment of the present invention, it is particularly advantageous if the cooling plate has at least a first cooling channel area and a second cooling channel area, which are arranged at a distance from each other, wherein the first cooling channel area and the second cooling channel area are configured to project into a cooling water system. The respective cooling channel areas can be assigned to different electrical components and be flow-optimized, so that pressure losses in a cooling water system are reduced.

[0015] Furthermore, it has proven advantageous for the heat-conducting plate to be a thin-walled, deep-drawn component. Such components are cost-effective to manufacture and easy to handle. In addition, thin-walled components exhibit lower thermal resistance.

[0016] According to a further advantageous embodiment of the present invention, the heat-conducting plate and the cooling channel plate are connected to each other by a welded joint. The weld is pressure-tight and seals the working fluid, which is contained in a vacuum, in the cavity between the heat-conducting plate and the cooling channel plate.

[0017] Furthermore, it is particularly advantageous if the working fluid has a freezing point of less than -40 °C, so that such a cooling plate can also be used in cold ambient conditions.

[0018] Preferably, the at least one cavity is filled with a fleece, a fabric, a pellet and / or a porous material to generate a capillary effect.

[0019] According to a further preferred embodiment of the present invention, an opening is incorporated into the cooling channel plate and / or the heat-conducting plate through which the working fluid can be introduced into the cavity and through which a vacuum is established in the cavity. The opening is then sealed pressure-tight, for example by means of a press-fit ball.

[0020] Furthermore, the present invention relates to a device comprising at least one electrical component, in particular a power electronics component, with at least one cooling plate according to the invention. drawing

[0021] A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 a schematic, partially cutaway view of a device comprising a plurality of electrical components and a cooling plate according to a preferred embodiment of the invention, and Fig. 2 a schematic, partially cutaway view of the device with a cooling plate according to Fig. 1 along the intersection line AA. Preferred embodiment of the invention

[0022] The following refers to the Fig. 1 and Fig. 2 a cooling plate 1 and a device 2 according to a first preferred embodiment of the invention are described in detail.

[0023] The device 2 comprises the cooling plate 1 and four electrical components 3, namely three power modules 31, 32, 33 and a film capacitor 34 or intermediate circuit capacitor, which form one or more heat sources 7. The cooling plate 1 has a first side 6 facing the power modules 31, 32, 33 and a second side 8 facing away from the power modules 31, 32, 33. The second side 8 faces a heat sink 9, which is designed, for example, as a cooling water system 30.

[0024] The sectional view in Fig. Figure 2 shows that the cooling plate 1 is formed from a heat-conducting plate 10 with a recess 12 and a cooling channel plate 11. The cooling channel plate 11 is fully inserted into the recess 12, thereby forming a planar cavity 15 in the cooling plate 1, which is aligned in a plane 17 parallel to the heat-conducting plate 10.

[0025] The cooling channel plate 11, shown in Fig. 2, on the side 8 facing the heat sink 9, has a first cooling channel area 21 and a second cooling channel area 22 with a plurality of cooling channels 29. The cooling channels 29 in the first cooling channel area 21 are formed from a so-called pinfin structure 19, which consists of a plurality of studs. The cooling channels 29 in the second cooling channel area 22 are formed by cooling fins 18. The cooling fins 18 and the pinfin structures 19 are in Fig. 1 indicated. The cooling fins 18 and the PinFin structure 19 have an increased surface area to improve heat transfer.

[0026] Fig. Figure 2 further indicates that the cavity 15 is dimensioned such that it is arranged parallel to and spaced apart from the electrical components 3 in the cooling plate 1 and completely covers them. Accordingly, the area of ​​the cavity 15 in plane 17 is larger than the area of ​​the electrical components 3.

[0027] Furthermore, the cavity 15 is designed in the manner of a heat pipe, thermosiphon, or vapor chamber and is preferably filled with a nonwoven fabric, woven fabric, or porous material and a working fluid 16. A capillary action is generated in the cavity 15 due to a multitude of capillaries, through which the working fluid 16 can be transported.

[0028] The working fluid 16 in the cavity 15 is a conventional refrigerant, such as water, alcohol, ammonia, or a mixture of such liquids. The working fluid 16 preferably has a freezing point below -40°C to ensure that the cooling plate 1 or the device 2 functions properly even in cold ambient conditions. The working fluid 16 is introduced into the cavity 15 through an opening 23 (not shown), and a vacuum is subsequently established in the cavity 15 to bring the working fluid 16 into a wet vapor state. The working fluid 16 must be selected appropriately for the application in accordance with environmental regulations and vapor pressure reserves. Furthermore, the working fluid 16 should be designed such that, at a maximum permissible temperature on the side of the cavity 15 facing the cooling channel plate 11, the working fluid 16 does not completely evaporate.

[0029] During operation, the working fluid 16 evaporates on side 6 facing the heat source 7. The working fluid 16 is then transported to side 8 in the cavity 15 facing the heat sink 9, condenses there, and is drawn back to side 6 facing the heat source 7 by capillary action. The cycle then begins anew. Due to the planar shape of the cavity 15 in the cooling plate 1, this process does not occur exclusively in a direction perpendicular to the plane 17, but essentially parallel to the plane 17. This results in heat spreading, which dissipates the heat released by the heat sources 7 and the electrical components 3 evenly across the entire surface of the cavity 15 to the cooling channel plate 11.

[0030] Due to the uniform temperature level through the cavity 15 and the large temperature difference, further advantages arise for the cooling water system 30. On the one hand, the density or number of cooling fins, cooling pins, etc., can be reduced, and on the other hand, the flow channel of the cooling water system 30 can be widened due to the large temperature difference. This minimizes the flow pressure losses in the cooling water system 30 and reduces the required pumping power of the cooling water system.

[0031] The cooling water system 30 according to Fig.1 is U-shaped, with a cooling water inlet 41 and a cooling water outlet 42 located on the same end face. The first leg of the U-shaped cooling water system 30 has a first widened area for the first cooling channel area 21 with the PinFin structures 19, and the second leg has a second widened cooling channel area 22 with the cooling fins 18. This arrangement is particularly advantageous given that the power modules 31, 32, 33, which require a high degree of cooling, are located above the first cooling channel area 21.

[0032] In the present embodiment, the heat conducting plate 10 and the cooling channel plate 11 are connected to each other in a pressure-tight manner by means of a welded connection 28.

[0033] Thus, according to the invention, a cooling plate 1 with the best possible heat dissipation for electronic components 3 can be provided, which achieves a uniform temperature level for all electronic components 3 arranged on the cooling plate 1 even with different power density and heat output, and which meets the requirements of low cost, minimal size and maximum performance.

Claims

[1] Cooling plate, in particular a cooling plate of an electrical appliance, comprising - a heat-conducting plate (10), and - at least one cooling channel plate (11) with at least one cooling channel (29), - wherein at least one recess (12) is arranged between the heat-conducting plate (10) and the cooling channel plate (11), - wherein at least one cavity (15) containing a working fluid (16) is arranged in the at least one recess (12), which is aligned in a plane (17) parallel to the heat-conducting plate (10), - wherein at least one cavity (15) is sealed in a pressure-tight manner, and - wherein the cooling channel plate (11) is arranged completely within the recess (12). [2] Cooling plate according to claim 1, characterized by , that the recess (12) is incorporated or molded into the heat-conducting plate (10). [3] Cooling plate according to one of the aforementioned claims, characterized by, that the cooling channel plate (11) has the cooling channel (29) with cooling fins (18) and / or a PinFin structure (19) on the side facing a heat sink (8). [4] Cooling plate according to claim 3, characterized by , that the cooling fins (18) and / or the PinFin structure (19) are arranged within the recess (12). [5] Cooling plate according to one of the preceding claims, characterized by , that the at least one cavity (15) is designed as a heat pipe, thermosiphon or vapor chamber. [6] Cooling plate according to one of the preceding claims, characterized by , that the cavity (15) is formed in some areas from the heat conducting plate (10) and / or from the cooling channel plate (11). [7] Cooling plate according to one of the preceding claims, characterized by, that the cooling channel plate (11) has at least one first cooling channel area (21) and at least one second cooling channel area (22) which are spaced apart from each other, wherein the first cooling channel area (21) and the second cooling channel area (22) are arranged to project into a cooling water system (30). [8] Cooling plate according to one of the preceding claims, characterized by , that the heat-conducting plate (10) is a thin-walled deep-drawn component. [9] Cooling plate according to one of the preceding claims, characterized by , that the heat conducting plate (10) and the cooling channel plate (11) are connected by a welded joint (28). [10] Cooling plate according to one of the preceding claims, characterized by that the working fluid (16) has a freezing point below -40 °C. [11] Cooling plate according to one of the preceding claims, characterized by , that a nonwoven fabric, a woven fabric or a porous material is arranged in the cavity (15). [12] Cooling plate according to one of the preceding claims, characterized by , that an opening (23) for filling the cavity (15) is incorporated into the cooling channel plate (11) and / or into the heat conducting plate (10), which is sealed in a pressure-tight manner. [13] Device comprising at least one electrical component (3), in particular a power electronics component, comprising at least one cooling plate (1) according to any one of claims 1 to 12.

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