DE102021211246A1 - Heat sink for cooling electronic components of an electrified motor vehicle drive - Google Patents

Abstract

The invention relates to a heat sink (100) for cooling electronic components (200) of an electrified motor vehicle drive, comprising two main cooling plates (110, 120) through which cooling fluid can flow, which each have two opposite longitudinal edges and two transverse edges standing transversely thereto ,- are at right or obtuse angles to one another, and- are structurally and fluidly connected to each other along one of their longitudinal edges, one of the main cooling plates (110) having a cooling fluid inlet (113) and the other main cooling plate (120) having a cooling fluid outlet ( 123). The invention is characterized in that at least one of the main cooling plates (110, 120) has a multi-flow, internal cooling channel structure, by means of which cooling fluid on its way from the cooling fluid inlet (113) to the cooling fluid outlet (123) in the connection area of the main - cooling plates (110, 120) can be guided perpendicularly to the longitudinal edges connected to one another and at a distance from this connection area parallel to the longitudinal edges connected to one another.

Description

• - jeweils zwei einander gegenüberliegende Längskanten und zwei quer zu diesen stehende Querkanten aufweisen,
• - zueinander in einem rechten oder stumpfen Winkel stehen und
• - entlang je einer ihrer Längskanten strukturell und fluidleitend miteinander verbunden sind,

wobei eine der Haupt-Kühlplatten einen Kühlfluideinlass und die andere Haupt-Kühlplatte einen Kühlfluidauslass aufweist.The invention relates to a heat sink for cooling electronic components of an electrified motor vehicle drive, comprising two main cooling plates through which cooling fluid can flow

• - each have two opposite longitudinal edges and two transverse edges standing transversely to these,
• - stand at right or obtuse angles to each other and
• - are structurally and fluidly connected to each other along one of their longitudinal edges,

wherein one of the main cooling plates has a cooling fluid inlet and the other main cooling plate has a cooling fluid outlet.

Such a heat sink is known from EP 3 340 292 A1 .

To operate electric drive units in fully or partially electrified motor vehicle drives, very high electrical currents have to be handled. This is done by the so-called power electronics, which include pulse-controlled inverters in particular, which on the one hand are able to convert direct current supplied by a traction battery into alternating currents that are in phase with the motor operation of the drive unit, and on the other hand are able to convert alternating currents generated by a generator-operated drive unit to charging the traction battery into direct currents. Due to the high currents switched, there is a significant accumulation of heat loss, which must be dissipated efficiently and in particular in a space-saving manner in order to be able to be used again optimally elsewhere to improve the overall energy efficiency.

For heat dissipation, heat sinks through which cooling fluid flows are typically used, on the outer walls of which the electronic components to be cooled, in particular capacitors and transistors integrated in so-called power modules, are thermally coupled.

Such a heat sink is known from the generic document mentioned at the outset, which essentially consists of two hollow main cooling plates which are at an angle to one another and are fixed to one another with one of their longitudinal edges and are connected to one another in a fluid-conducting manner. On the respective free longitudinal edges, these are open in profile in each case as a leg of an “L”-forming main cooling plate. Here there is a cooling fluid inlet on a first main cooling plate and a cooling fluid outlet on the other main cooling plate. In operation, cooling fluid is pumped under pressure from the cooling fluid inlet to the cooling fluid outlet, flowing first through the first and then through the second main cold plates. Taking the aforementioned L-profile as a basis, the cooling fluid thus first flows through the vertical and then the horizontal leg of the L. This is disadvantageous in two respects. On the one hand, the components that are thermally coupled to the horizontal leg of the L are fed exclusively with cooling fluid that has already been preheated in the vertical leg of the L. On the other hand, it is difficult in terms of flow technology to achieve a surface flow that is uniform and exactly reproducible in all driving and pressure situations, especially in the case of cooling plates that extend long in the longitudinal direction. The positioning of the individual components must therefore be designed strictly according to the respective relation between the cooling requirement of the component and the cooling capacity of the corresponding position on the heat sink. This severely restricts the design freedom in arranging the electronic components and thus the optimization of installation space that is always desired. In addition, such a construction will generally not be able to be optimized with regard to its energy efficiency.

It is the object of the present invention to further develop a generic heat sink in such a way that, with at least the same, preferably improved, energy efficiency, a broader range of structural options for arranging the electronic components to be cooled is available.

This object is achieved in connection with the features of the preamble of claim 1 in that at least one of the main cooling plates has a multi-flow, internal cooling channel structure, by means of which cooling fluid on its way from the cooling fluid inlet to the cooling fluid outlet in the connection area of the main cooling plates perpendicular to the connected longitudinal edges and spaced from this connection area parallel to the interconnected longitudinal edges can be guided.

Preferred embodiments of the invention are the subject of the dependent claims.

A more uniform temperature distribution over the entire surface of the cooling plate can be achieved by the multi-flow routing of the cooling fluid. Therefore, different positions on the cooling plate surface are thermally significantly more equivalent than is the case in the prior art.

Furthermore, the invention provides for the flow of cooling fluid only in the connection area of the two To steer cooling plates perpendicular to the common or the interconnected longitudinal edges, which is favorable in order to achieve the cooling fluid transition from the inlet-side to the outlet-side cooling plate. Otherwise, ie at a distance from this transition or connection area, the cooling fluid flows essentially parallel to the longitudinal edges, so that, in contrast to the prior art, there is no steep temperature gradient from the free to the connected longitudinal edge of the cooling plate. This achieves a further equalization of the temperature distribution over the entire surface of the cooling plate.

The combination of the two ideas according to the invention results in a special temperature equalization over the entire surface of the cooling plate, so that electronic components to be cooled can no longer be arranged according to their cooling requirements, but according to virtually any other criteria, for example with regard to optimizing the installation space .

This concept is preferably implemented with both cooling plates of the heat sink.

In order to keep the pressure losses in the cooling fluid as low as possible on its way from the cooling fluid inlet to the cooling fluid outlet, it is preferred to keep the flow guidance as straight as possible, apart from the deflections required according to the invention. This contributes in particular if the cooling fluid inlet and the cooling fluid outlet are arranged on opposite transverse edges of the main cooling plates. The cooling fluid thus already flows parallel to the interconnected or common longitudinal edge into the first cooling plate, is deflected perpendicularly thereto in the transition or connection region of the cooling plates, is preferably further deflected in the second cooling plate parallel to the common longitudinal edge and can then emerge largely in a straight line from the cooling fluid outlet arranged on the opposite transverse edge from the heat sink.

In order to ensure that the cooling fluid is guided in a sealed manner, the heat sink must of course be designed to be closed, apart from the cooling fluid inlet and outlet. However, it has proven useful if at least one of the main cooling plates is designed as a one-piece, open trough whose open channel structure can be closed or closed by means of a flat cooling cover. This is preferably the case for both main cooling plates, namely these can then be produced individually or—particularly preferably—together in one piece in a cost-effective production process, for example as injection-molded parts. The cooling cover or covers, to which the electronic components to be cooled are or will be thermally coupled, can then be subsequently placed and sealed. The cooling covers can then be optimized with regard to their function as a heat exchanger from the cooling fluid to the electronic components and, if necessary, can be of quite complex design, without this unnecessarily complicating the manufacturing process of the rest of the cooling body. The thermal and possibly simultaneously mechanical coupling of the electronic components to the cooling cover, which can be achieved for example by very special soldering, sintering or laminating processes, can be carried out independently of the production or any thermal sensitivities of the rest of the cooling body. It can be advantageous if the cooling cover with the electronic components already fixed on it is placed on to cover and seal the hitherto open troughs of the main cooling plates manufactured independently of it. However, an alternative method is particularly preferred in which the heated cooling cover made of a metallic material is pressed onto the upper edge of the associated pan made of a thermoplastic material and is thereby melted to form a tight and mechanically strong connection to the pan. The electronic components can later be fixed on the cooling cover at lower process temperatures.

It is possible and is considered favorable if the cooling cover of at least one main cooling plate has heat-conducting and/or turbulence elements projecting into its interior. For example, nub or rib structures can be provided here, which bring about an improvement in the heat exchange between the cooling cover or the electronic components coupled to it and the cooling fluid flowing inside the cooling body.

In any case, the (approximate) L-shape of the heat sink according to the invention allows the coupled electronic components to be cooled on one side. However, some electronic components require two-sided cooling. With the L-shape of the heat sink according to the invention, this is possible at most in the area of the inner angle between the two main cooling plates. However, this leads to a very asymmetrical cooling of an element arranged in this gusset. In a further development of the invention, it is therefore provided that the cooling body additionally has an additional cooling plate through which cooling fluid can flow, which is aligned parallel to one of the main cooling plates and is spaced from it at its outer angle relative to the angle enclosed between the main cooling plates side arranged net is. This creates a gap between the outside of the corresponding main cooling plate and said additional cooling plate, in which correspondingly dimensioned electronic components can be inserted and coupled with both cooling plates to achieve cooling on both sides.

Conveniently, that main cooling plate to which said additional cooling plate is aligned parallel is the main cooling plate on the output side. In other words, it is preferably provided that the additional cooling plate is aligned parallel to the main cooling plate having the cooling fluid outlet. The background to this design is that despite the inventive equalization of the temperature distribution, a temperature gradient between the inlet-side and the outlet-side main cooling plate is unavoidable, although this effect is already significantly reduced according to the invention compared to the prior art. However, the cooling of the electronic components arranged on the main cooling plate on the output side can never reach the same level as the cooling of the components arranged on the main cooling plate on the input side. The additional cooling achieved by the additional cooling plate can be used to compensate for this difference. Alternatively or additionally, it can be used to meet different cooling needs of different electronic components. This is particularly the case when the main cooling plate on the input side is equipped with less cooling-intensive components, such as condensers, which heat the cooling fluid only slightly, so that components that require more cooling, such as power modules, which are arranged on the main cooling plate on the output side, are equipped on the one hand by means of Cooling fluids at a temperature (still) can be cooled close to its input temperature and, on the other hand, experience additional cooling via the additional cooling plate.

It is preferably provided that the additional cooling plate is fluid-conductively connected directly to the cooling fluid inlet in the area of one of its transverse edges and directly to the cooling fluid outlet in the area of its opposite transverse edge. This results in a fluid flow through the additional cooling plate that is parallel to the fluid flow through the main cooling plate and the electronic components arranged on the main cooling plate on the outlet side are also supplied with fresh, i.e. not preheated, cooling fluid. Due to the double cooling of these components, however, the fluid flow through the additional cooling plate can be designed to be significantly smaller and less complex.

In particular, it has been shown that linear guidance over the length of the additional cooling plate, i.e. parallel to the longitudinal edges of the main cooling plates connected to one another, can be sufficient.

Further features and advantages of the invention result from the following specific description and the drawings.

• 1 eine perspektivische Darstellung einer Leistungselektronik mit erfindungsgemäßem Kühlkörper,
• 2 die Leistungselektronik von 1 in geschnittener Darstellung,
• 3 die Leistungselektronik von 1 mit ausgeblendeter Kondensatoranordnung,
• 4 der erfindungsgemäße Kühlkörper von 1 mit ausgeblendetem Powermodul-Kühldeckel,
• 5 die Powermodul-Anordnung der Leistungselektronik von 1 und
• 6 die Leistungselektronik von 1 in senkrecht zu 2 geschnittener Darstellung.

Show it:

• 1 a perspective view of power electronics with a heat sink according to the invention,
• 2 the power electronics of 1 in cut representation,
• 3 the power electronics of 1 with blanked capacitor arrangement,
• 4 the heat sink according to the invention 1 with hidden power module cooling cover,
• 5 the power module arrangement of the power electronics from 1 and
• 6 the power electronics of 1 in perpendicular to 2 cut representation.

The same reference symbols in the figures indicate the same or analogous elements.

The 1 until 6 show power electronics 10 with a particularly preferred embodiment of a heat sink 100 according to the invention in various cut and assembly or blanking configurations. In the following, the figures are essentially to be described together, although specific figures are specifically referred to on a case-by-case basis in order to emphasize certain features. In the illustrated embodiment, the heatsink 100 comprises two main cooling plates 110, 120 arranged in a substantially L-shape with respect to one another. In the illustrated embodiment, each of the main cooling plates 110, 120 comprises an open trough 111, 121 which is closed in a fluid-tight manner by means of an associated cooling cover 112, 122. The cooling cover 112 of the first main cooling plate 110, which is shown in the figures in a horizontal orientation, is arranged on the inside in relation to the (right) angle enclosed between the main cooling plates 110, 120, ie it represents the inner surface of the first Main cooling plate 110. The cooling cover 122 of the second main cooling plate 120, which is shown in the figures in vertical orientation, is arranged outwardly with respect to the (right) angle between the main cooling plates 110, 120, ie it represents the outer surface the second main cooling plate 120.

Tub 111, 121 and cooling lid 112, 122 each form a substantially hollow main cooling plate 110, 120 through which a cooling fluid, typically cooling oil or water containing glycol, can flow. The two main cooling plates 110, 120 are not only mechanically but also fluidly connected to one another. For this purpose, there are transition lines 130 in the area of the common longitudinal edge or the longitudinal edges of the main cooling plates 110, 120 connected to one another. A cooling fluid inlet 113 and a cooling fluid outlet 123 are arranged on opposite transverse edges of the first main cooling plate 110 on the one hand and the second main cooling plate 120 on the other , which merge into a socket-like feed channel 114 or discharge channel 124, to which cooling fluid lines can be connected to form an active cooling fluid circuit.

Guide ribs 115, 125 are arranged inside each of the main cooling plates 110, 120, by means of which cooling fluid, which is pumped via the supply channel 114 into the cooling body 100 and out of the discharge channel 124, is guided within the cooling body 100 in a manner specific to the invention. Thus, the flow of cooling fluid introduced through the cooling fluid inlet 113 into the first main cooling plate 110 is initially split into multiple flows, in particular three flows, by means of the guide ribs 115 located there. It then flows in three flows, initially parallel to the longitudinal edges, in order to then be deflected transversely thereto by the guide ribs 115 onto the transition area between the two main cooling plates 110, 120. There it then enters the second main cooling plate 120 through the transfer lines 130 in order to be guided there in multiple flows and transversely to the longitudinal edges. It is then deflected parallel to the longitudinal edges to the cooling fluid outlet 123 by the guide ribs 125 there. The individual partial flows are reunited there in order to be discharged together via the discharge channel 124 . This special guidance of the cooling fluid leads to a considerable equalization of the temperature distribution over the surfaces of the main cooling plates 110, 120, in particular over the surfaces of their cooling covers 112, 122.

The cooling covers 112, 122 are fitted with electronic components 200 which are mechanically and thermally connected there. In the embodiment shown, the cooling cover 112 of the first main cooling plate 110 is equipped with intermediate circuit capacitors 210 and the cooling cover 122 of the second main cooling plate 120 is equipped with so-called power modules 220 . These electronic components 200 can emit heat to the cooling fluid via the respectively associated cooling cover 112, 122. In order to improve this heat exchange, the cooling covers 112, 122 have heat-conducting and/or turbulence elements 116, 126 on their respective inner sides, i.e. the side directed towards the interior of the respectively assigned main cooling plate 110, 120. In the case of the first main cooling plate 110, the associated heat-conducting and/or turbulence elements 116 are designed in the manner of knobs. In the case of the second main cooling plate 120, the associated heat-conducting and/or turbulence elements 126 are designed in the manner of ribs.

While the intermediate circuit capacitors 210 in the embodiment shown are only cooled on one side, the power modules 220 are cooled on both sides. An additional cooling plate 150 is used for this purpose, which is pressed by means of a spring plate 140, which is held parallel to the cooling cover 122 of the second main cooling plate 120 with fixing bolts 141, against the power modules 220 fixed on its surface. Like the main cooling plates 110, 120, the additional cooling plate 150 is in two parts, specifically in the form of an open trough 151 and a cooling cover 152 closing it. The cooling cover 152 of the additional cooling plate 150 is in contact with the power modules 220 and is equipped with heat conducting and/or turbulence elements 156 on its inside. Cooling fluid can also flow through the additional cooling plate 150 . For this purpose, it is connected to the cooling fluid inlet 113 on the one hand and to the cooling fluid outlet 123 on the other hand via two channel-like transfer lines 131, of which only the inlet side can be seen in the figures. In the illustrated embodiment, no special guide ribs for directing the cooling fluid are provided within the additional cooling plate 150 . In the illustrated embodiment, the additional cooling plate 150 is therefore flowed through linearly parallel to the longitudinal edges.

Of course, the embodiments discussed in the specific description and shown in the figures only represent illustrative exemplary embodiments of the present invention. In particular, the joint one-piece design of the troughs 111, 121 of the main cooling plates 110, 120 shown in the figures is not central to the invention, although it is particularly preferred and advantageous especially with regard to cost advantages in production. In alternative configurations, the heatsink 100 may also be fabricated as an assembly from a larger number of elements. Equipping both main surfaces of at least one of the main cooling plates 110, 120 with electronic components 200 is also conceivable.

Reference List

10

power electronics

100

heatsink

110

first main cold plate

111

tub of 110

112

Cooling cap from 110

113

cooling fluid inlet

114

feed channel

115

guide rib

116

Heat conducting and/or turbulence element

120

second main cooling plate

121

tub of 120

122

Cooling cap from 120

123

cooling fluid outlet

124

drainage channel

125

guide rib

126

Heat conducting and/or turbulence element

130

Transition between 110 and 120

131

Reconciliation between 110 and 150

140

spring plate

141

fixing bolts

150

Additional cooling plate

151

tub of 150

152

Cooling cap from 150

156

Heat conducting and/or turbulence element

200

electronic components

210

intermediate circuit capacitor

220

power module

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3340292 A1 [0002]

Claims (10)

Heat sink (100) for cooling electronic components (200) of an electrified motor vehicle drive, comprising two main cooling plates (110, 120) through which cooling fluid can flow, which - each have two opposite longitudinal edges and two transverse edges standing transversely to these, - each other in a right or obtuse angles and - are structurally and fluidly connected to each other along one of their longitudinal edges, one of the main cooling plates (110) having a cooling fluid inlet (113) and the other main cooling plate (120) having a cooling fluid outlet (123), characterized that at least one of the main cooling plates (110, 120) has a multi-flow, internal cooling channel structure, by means of which cooling fluid flows perpendicular to the interconnected longitudinal edges and spaced from this connection area parallel to the interconnected longitudinal edges can be guided. Heat sink (100) after claim 1 , characterized in that each of the main cooling plates (110, 120) has a multi-flow, internal cooling channel structure, by means of which cooling fluid is perpendicular on its way from the cooling fluid inlet (113) to the cooling fluid outlet (123) in the connection area of the main cooling plates (110, 120). to the interconnected longitudinal edges and spaced from this connection area parallel to the interconnected longitudinal edges can be guided. Heat sink (100) according to one of the preceding claims, characterized in that the cooling fluid inlet (113) and the cooling fluid outlet (123) are arranged on opposite transverse edges of the main cooling plates (110, 120). Cooling body (100) according to one of the preceding claims, characterized in that at least one of the main cooling plates (110, 120) is designed as a one-piece, open trough (111, 121), the open cooling channel structure of which is covered by a flat cooling cover (112, 122 ) is lockable or locked. Heat sink (100) after claim 4 , characterized in that each of the main cooling plates (110, 120) is designed as a one-piece, open trough (111, 121) whose open cooling channel structure can be closed or closed by means of a flat cooling cover (112, 122). Heat sink (100) after claim 5 , characterized in that the troughs (111, 121) of both main cooling plates (110, 120) are formed together in one piece. Heat sink (100) according to one of Claims 4 until 6 , characterized in that the cooling cover (112, 122) of at least one main cooling plate (110, 120) has heat conducting and/or turbulence elements (116, 126) projecting into its interior. Cooling body (100) according to one of the preceding claims, characterized in that the cooling body (100) has an additional cooling plate (150) through which cooling fluid can flow, which is aligned parallel to one of the main cooling plates (110, 120) and spaced from it whose - relative to the angle enclosed between the main cooling plates (110, 120) - is arranged on the outer side. Heat sink (100) after claim 8 , characterized in that the additional cooling plate (150) is aligned parallel to the cooling fluid outlet (123) having the main cooling plate (120). Heat sink (100) according to one of Claims 8 until 9 , characterized in that the additional cooling plate (150) in the region of one of its transverse edges is fluidly connected directly to the cooling fluid inlet (113) and in the region of its opposite transverse edge directly to the cooling fluid outlet (123).

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