Abstract:
The invention relates to a module with a number of electrical or electronic components or switching circuits provided on a common cooler structure flowed through by a cooling medium. The entire cooler structure is made up of at least two plate-shaped coolers, which are arranged parallel to one another in an interspaced manner and which are flowed through by the cooling medium.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to an electric or electronic module with several electric or electronic components or circuits provided on a common cooler structure perfused by a coolant. 
         [0002]    It is an object of the invention is to present a module which can be achieved in a very compact design by means of a simplified manufacturing process. 
       SUMMARY OF THE INVENTION 
       [0003]    In a preferred embodiment, the electric module is designed so that the common cooler structure consists of at least two plate-shaped coolers perfused by the coolant and arranged parallel to each other and at a distance from each other, that at least one circuit on a cooler is provided in a space between two adjacent coolers, that each cooler consists of several interconnected layers of sheet or roll metal, that inner layers of each cooler are structured by openings made in said layers resulting in an inner structured cooling area, which forms a flow channel for the coolant that constantly branches off in all three spatial axes, and that the interconnected layers form continuous posts in the structured area, the posts extend to the top and bottom side or to the top and bottom side of the respective cooler. 
         [0004]    One of the advantages of this embodiment is that this special design of the cooler (consisting of several interconnected layers of metal foil with a constantly branching flow channel formed by the structuring of the inner layers) achieves high cooling power with the coolant perfusing the cooler. The posts that are formed by the structuring of the inner layers and that extend between the top and bottom of the respective cooler also achieve high stability of the individual coolers, in particular so that the latter do not expand with the pressure of the coolant. This prevents the risk of unwanted contact or electrical contact so that the high cooling capacity and the high stability of the cooler enable a very compact design of the module with densely arranged coolers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The invention is explained below in more detail based on exemplary embodiments with reference to the drawings, wherein: 
           [0006]      FIG. 1  is a simplified representation in cross section of an actively cooled module according to the invention; 
           [0007]      FIG. 2  is a top view of the module of  FIG. 1 ; 
           [0008]      FIG. 3  is a perspective view of a spacer for use in the module of  FIG. 1 ; 
           [0009]      FIGS. 4 &amp; 5  are partial views of two inner layers of a cooler for use in the module of  FIGS. 1 and 2 ; 
           [0010]      FIGS. 6 &amp; 7  are partial views of consecutive layers in the area of a circuit in various embodiments; 
           [0011]      FIG. 8  is a partial view of a spacer and connecting element for use in a module according to the invention; and 
           [0012]      FIG. 9  is a view similar to  FIG. 2  of a further possible embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    In the drawings,  1  is an electric or electronic module, which consists of several—in the depicted embodiment a total of three—plate-shaped coolers  2  arranged parallel to each other and at a distance from each other, each of which in the depicted embodiment is provided on the top side with an electronic circuit  6  comprising several electric components, for example components  3 ,  4  and  5 . 
         [0014]    At least one of these components, for example the component  5 , is a power component, for example an electric resistor, a diode, a transistor, an IGB, a thyristor, triac, etc., which generates a considerable power loss during operation and for this reason must be cooled with the corresponding cooler  2 . In the practical embodiment, the components  3 - 5  of each circuit  6  are accommodated in a closed housing  6 . 1 , i.e. injection molded with plastic, for example. 
         [0015]    Each cooler  2  is manufactured of thin metal layers or sheets made of a suitable, thermally conductive material, for example of copper, namely of inner layers  7  and  8  and of outer layers  9 . The inner layers  7  and  8  are structured or provided with a plurality of openings in the manner depicted in  FIGS. 3 and 4 , so that this structuring of the openings  7 . 1  and  8 . 1 , corresponding to the dashed line  10  in  FIG. 2 , produces an inner cooler structure with a constantly branching flow channel in all three spatial axes for the coolant perfusing the cooler  2 . Further, the structuring is executed so that the successive, interconnected layers  7  and  8  form continuous posts  11 , which extend to the outer layers  9  and are connected with the latter. The posts  11  achieve increased stability of the respective cooler  2 , in particular also against expanding when the cooler  2  is perfused with a pressurized coolant. Further, the posts  11  serve as thermal conductors for dissipating heat from the top of the cooler  2  comprising the respective circuit  6 , also in such areas of the inner cooler structure  10  that are remote from said top side, therefore significantly improving the effectiveness of the respective cooler  2 . Further, the posts  11  perfused by the coolant also significantly increase the effective inner cooling area. 
         [0016]    The embodiment of the cooler  2  described above results in a cooling surface formed by the inner cooler structure  10  that is significantly larger than the surface occupied by the respective circuit  6  on the outer or top surface of the respective cooler. The inner cooling surface is larger by a factor of at least three than the outer surface of the cooler  2  on its top or bottom side, in any case larger by a factor of three than the outer cooler surface occupied by the circuit  6 . 
         [0017]    The top and bottom side of each cooler  2  is formed by a layer  9 , respectively, which seals the inner cooler structure  10  on the respective side of the cooler  2  toward the outside. The structuring of the layers  7  and  8  is designed so that the screen-like area formed by the openings  7 . 1  and  8 . 1  is surrounded by a closed edge, so that the structured area  10  formed by the openings  7 . 1  and  8 . 1  and perfused by the coolant is also sealed on the periphery of each cooler  2 . 
         [0018]    In the depicted embodiment the layers  7 - 9  each have a rectangular shape, so that the coolers  2  are also rectangular in top view. In the area of the two narrow sides each cooler  2  is provided with a continuous bore hole  12  and  13 , respectively, which extends from the top to the bottom of the respective cooler  2  and serves to supply the coolant (hole  12 ) and remove the coolant (hole  13 ). The holes  12  and  13 , which are produced for example by corresponding structuring of the layers  7 - 9  or by machining of the cooler  2  after bonding of the layers  7 - 9 , each lead into the structured area  10 . 
         [0019]    As shown in  FIG. 1 , the individual coolers  2  are kept at a distance from each other by spacers  14 , which are provided on the narrow sides of the coolers  2 . The spacers  14  are cube-shaped as shown in  FIG. 3  and lie with their longitudinal extension parallel to and also flush with the respective narrow side. Each spacer has a bore hole  15 , which in the mounted state of the module  1  is congruent with a bore hole  12  or  13 , so that the holes  15  and  12  or  15  and  13 , respectively, lead to a channel for supplying or removing the coolant. On the lower coolers  2  in  FIG. 1 , an end element  16  is provided in the area of each narrow side, which (end element) corresponds in design and shape for example to a spacer  14  without a bore hole  15 , but preferably with a reduced thickness as compared with the spacers  14 . 
         [0020]    To hold together the structure consisting of the coolers  2 , the spacers  14  and the end elements  16  in the depicted embodiment, a top and a bottom holding or clamping plate  17  and  18  are provided, which are oriented with the surface sides parallel to the top side of the coolers  2 . 
         [0021]    The top clamping plate  17  is kept at a distance from the adjacent top cooler  2  by means of two spacers  14 . The lower holding plate  18  bears with a surface side facing the coolers  2  against the two end elements  16 . Several clamping screws or bolts not depicted, which are provided in congruent openings  19  in the coolers  2 , the spacers  14 , the end elements  16  and the clamping plates  17  and  18 , clamp the elements forming the module  1  together, as indicated by the dashed line  20 . In the upper clamping plate  17 , openings  21  are provided through which connecting tubes or connecting elements  22  are guided outward, by means of which the module  1  can then be connected with lines, not depicted, for supplying and removing the coolant. The connecting elements  22 , which are tubular in the depicted embodiment, are held with an end in a bore hole  15  of the spacers  14  provided between the clamping plate  17  and the adjacent cooler  2 , namely for example by being screwed into an internal thread of the corresponding bore hole  15 . 
         [0022]    For a sealed transition between the coolers  2  and the spacers  14  and the end elements  16 , seals, e.g. ring seals  23 , are provided. For exact positioning of these seals, the spacers  14  are provided for example with recesses enclosing openings of the bore holes  15  for partially holding each seal  23 . The end elements  16  also have corresponding recesses. The spacers  14  and the end elements  15  are manufactured for example from an electrically insulating material, for example as plastic molded or injection molded parts. 
         [0023]    The thickness of the spacers  14  and therefore the distance between the adjacent coolers  2  is selected on the one hand so as to produce a compact design for the module  1  and on the other hand so that the space  24  between two coolers  2  or between the top clamping plate  17  and the adjacent cooler  2  is sufficient for the respective circuit  6 , which is provided between the two narrow sides of the cooler  2  and therefore between two spacers  14  on the cooler. The connections  25  (voltage connections, control connections, etc.) in the depicted embodiment are guided outward on the longitudinal sides of the cooler  2  and therefore on the longitudinal sides of the module  1 , as depicted in  FIG. 2 . This enables an especially easy connection with external connecting elements or lines. Preferably the connections  25  are then provided in a defined array, to enable connection of the entire module  1  and its connections  25  by plugging it into external multiple-terminal strips. 
         [0024]    As shown in  FIG. 7 , the circuits  6  are each manufactured using a substrate  26 , which comprises for example an insulating layer, i.e. in the depicted embodiment a ceramic layer  27 , which is metallized on both surfaces, i.e. in the depicted embodiment is provided with a copper layer  28  and  29 . Of these copper layers, which for example are provided on the ceramic layer  27  (e.g. Al 2 O 3  ceramic) by means of known DCB (Direct Copper Bonding) technology, the copper layer  28  is correspondingly structured to form strip conductors, connections and contact or mounting surfaces for the components  3 - 5 , etc. The copper layer  29  is bonded two-dimensionally in a suitable manner with the top side of the respective cooler  2 , for example by gluing using a thermally conductive adhesive, by soldering (also active soldering) or by direct bonding (DCB) or active soldering; if the substrate  26  is manufactured by direct bonding (DCB), said substrate is already manufactured during the manufacture of the cooler. 
         [0025]    Therefore, two basic possibilities exist for the manufacture of the coolers provided with the circuits  6 , namely in the form that the circuits  6  and the coolers  2  are manufactured in separate processes and then bonded, the circuits  6  by first manufacturing the substrates  26 , structuring the copper layer  26  and then mounting the components  3 - 5  and finally injection molding with plastic to form the respective housing  6 . 1 . The substrates manufactured in this manner are then mounted on the respective pre-fabricated coolers  2 . The advantage of this manufacturing method is that the substrates  26  can be manufactured, structured and mounted in multiple printed panels. 
         [0026]    The other basic method is to manufacture the substrate  26  together with the respective cooler  2  and then to structure the copper layer  28  to form strip conductors, contact surfaces, etc. Afterwards, the components  3 - 5  are mounted and the plastic is injection molded to form the respective housing  6 . 1 . 
         [0027]    All methods have in common that the coolers  2  are assembled to form the module  1  only after being provided with the circuits  6 , in order to enable the desired compact design by means of a simplified manufacturing process. 
         [0028]      FIG. 7  shows in a depiction similar to  FIG. 6  the layer structure in the area of a circuit  6 . The substrate  26   a  used for this structure differs from the substrate  26  in that the ceramic layer  27  is applied directly to the top surface of the respective cooler  2 , namely using a suitable bonding technology, e.g. direct bonding or active soldering. 
         [0029]      FIG. 8  shows in a simplified depiction a spacer and connecting element  30 , which is manufactured for example as a molded plastic part, so that with its comb-like structure it forms the spacers  15  and the end element  16  for a narrow side of the module  1 , respectively. Combining the spacers  14  and the end element  16  to form a single component considerably simplifies the mounting of the module, i.e. after insertion of the seal rings  23 , the coolers  2  provided with the circuits  6  are inserted respectively into the recesses  31  formed by the comb-like structure and then clamped by means of the clamping bolts  20  with each other and also with the holding and clamping plates  17  and  18 . 
         [0030]    As shown in  FIG. 1 , the coolant is supplied and removed via the connecting elements  22  at the top of the module, i.e. at the top clamping plate  17 . To achieve the best possible distribution of the coolant to all coolers  2  and therefore even cooling of the circuits  6 , the structuring  10  of each cooler  2  is designed at least in the area of the opening.  12 , but preferably also in the area of the opening  13 , so that the effective cross section of flow at the transition between the bore hole  12  or  13  and the structured area  10  is smaller than the cross section of said bore holes or of the channels formed by the bore holes  12 ,  13  and  15 . 
         [0031]    To improve the evenness of the perfusion of all coolers  2 , it can be effective to provide a connecting element  22 , for example for the supply of the coolant on the top side of the module and the other connecting element  22 , for example for removing the coolant on the bottom side of the module, i.e. in the area of the clamping plate  18  located there, in order to achieve a diagonal perfusion of the module  1 . 
         [0032]    As indicated in  FIG. 9 , it is further possible to form a further channel in addition to one of the channels created using the bore holes  12  or  13  and  15 . This further channel is formed by an additional bore hole  13   a  in the coolers  2  and congruent bore holes in the spacers  14  and the respective narrow side of the module  1 . Further, the lower end element  16  on this side of the module  1  is designed so that it connects the bore hole  13  there with the bore hole  13   a  and the upper spacer  14  on this narrow side is designed so that it closes the bore hole  13 . The bore holes  13   a  are outside of the structured area  10  of the coolers  2 . Due to the additional channel formed by the bore holes  13   a  and the corresponding bore holes in the spacers  14 , despite the optimum diagonal perfusion of the cooler array for the even distribution of the coolant, it is possible to provide the connections for supplying and removing the coolant on a common side, e.g. on the top side of the module. 
         [0033]    The individual coolers  2  are preferably designed sot that they have a cooling capacity of at least 25 W/cm 2 , namely relative to the surface occupied by the respective substrate  6 , i.e. the coolers  2  can be used to cool components or circuits  6  that generate a power loss of at least 25 W/cm 2  on their surface that is connected with the cooler  2 . 
         [0034]    The invention was described above based on exemplary embodiments. It goes without saying that numerous modifications and variations are possible without abandoning the underlying inventive idea upon which the invention is based. For example, it is possible to provide one or more coolers  2  also with one or more circuits  6  on their bottom side facing away from the clamping plate  17 . 
       REFERENCE LIST 
       [0035]      1  module 
         [0036]      2  cooler 
         [0037]      3 ,  4 ,  5  components 
         [0038]      3 . 1  housing 
         [0039]      6  circuit 
         [0040]      7 ,  8 ,  9  layer 
         [0041]      7 . 1 ,  8 . 1  opening 
         [0042]      10  structuring 
         [0043]      11  post 
         [0044]      12 ,  13 ,  13   a  bore hole 
         [0045]      14  spacer 
         [0046]      15  bore hole 
         [0047]      16  end element 
         [0048]      17 ,  18  holding or clamping plate 
         [0049]      19  opening 
         [0050]      20  clamping bolt 
         [0051]      21  opening 
         [0052]      22  connecting element 
         [0053]      23  seal ring 
         [0054]      24  intermediate space 
         [0055]      25  connection 
         [0056]      26 ,  26   a  substrate 
         [0057]      27  ceramic layer 
         [0058]      28 ,  29  copper layer 
         [0059]      30  spacer and connecting element 
         [0060]      31  intermediate space