NL2027865A

NL2027865A - Insulated-gate bipolar transistor module cooling system

Info

Publication number: NL2027865A
Application number: NL2027865A
Authority: NL
Inventors: Job Heusinkveld Jorrit
Original assignee: E Traction Europe Bv
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2022-11-15
Also published as: NL2027865B1

Abstract

An insulated-gate bipolar transistor (IGBT) module cooling system comprising: a housing enclosing a hollow space, comprising an inlet and an outlet, positioned opposite one another in opposing sides of the housing for flow of cooling liquid through said hollow space, and a mounting surface for mounting a base plate of the IGBT module thereon positioned parallel to said inlet and outlet, and comprising a through opening to said hollow space for allowing cooling liquid in the hollow space to directly contact the base plate of the IGBT module, and wherein an insert is provided inside the hollow space, comprising a flat surface shaped to match the through-opening and placed substantially parallel to the mounting surface at a predetermined distance therefrom, the insert further comprising one or more elements adapted to divert the flow of cooling liquid from a substantially linear path between the inlet and the outlet.

Description

P6091353NL { -1- Insulated-gate bipolar transistor module cooling system Field of the invention

[0001] The present invention relates to an insulated-gate bipolar transistor (IGBT) module cooling system comprising: an inlet and an outlet, positioned oposite one another in sides of a hollow space for flow of cooling liquid through said hollow space from said inlet to said outlet; and a mounting surface for mounting a base plate of the IGBT module thereon positioned parallel to said inlet and outlet, and comprising a through opening to said hollow space for allowing cooling liquid in the hollow space to directly contact the base plate of the IGBT module. The invention further relates to a method for installing such a cooling system onto an IGBT module and a method of manufacturing such a cooling system. Background art

[0002] An insulated-gate bipolar transistor (IGBT) module cooling system is known from US 2013/0134572. The document describes a semiconductor device including a semiconductor chip joined with a substrate and a base plate joined with the substrate. The base plate includes a first metal layer clad to a second metal layer. The second metal layer is deformed to provide a pin-fin or fin cooling structure. The second metal layer has a sub-layer that has no pins and no pin-fins. A chamber for receiving a cooling fluid is mounted against the base plate, said chamber including an inlet and an outlet for passing a cooling fluid through spaces between pin-fins or fins of the base plate. The pin-fins or fin cooling structure on the IGBT base plate cause disturbances in the flow of cooling fluid there through, resulting in turbulence which ensures the cooling fluid is mixed over the entire cooling fluid thickness between inlet and outlet. This ensures that heat produced by the IGBT during use is effectively removed, thereby improving the lifetime and efficiency of the IGBT.

[0003] Manufacturing of the base plate as described, however, is time consuming and relatively expensive. Furthermore, the IGBT base plate needs to be tailored for each IGBT lay-out design, such that no use can be made of standards IGBT modules. Summary of the invention

[0004] The present invention seeks to provide an improved direct cooling system for IGBT transistor modules which is easier and cheaper to manufacture.

[0005] According to a first aspect of the present invention, an IGBT is provided, comprising a housing enclosing a hollow space, comprising an inlet and an outlet, positioned opposite one another in opposing sides of the housing for flow of cooling liquid through said hollow space from said inlet to said outlet, and a mounting surface for mounting a base plate of the IGBT module thereon positioned parallel to said inlet and outlet, and comprising a through opening to said hollow space for allowing cooling liquid in the hollow space to directly contact the base plate of the IGBT module, wherein cross- sections of the hollow space parallel to the through opening are substantially equal in size and shape to the through opening, and in which an insert is provided inside the hollow space, comprising a flat surface shaped to match the through-opening and placed substantially parallel to the mounting surface at a predetermined

P6091353NL { -2- distance therefrom, the insert further comprising one or more elements adapted to divert the flow of cooling liquid from a substantially linear path between the inlet and the outlet.

[0006] This cooling system is easy to assembe due to being a two-piece system, comprising the housing and the insert, which can be manufactured independently and easily fitted together due to the insert having a flat surface which matches the through hole and hollow space of the housing. The IGBT module is bolied onto the cooling system, effectively closing the hollow space. Through this closing, the bottom plate of the IGBT module is in contact with the cooling liquid flowing through the cooling system, such that the IGBT module is cooled through its bottom plate. The one or more elements adapted to divert the flow of cooling liquid from a substantially linear path between the inlet and outlet prevent cooling liquid from forming a substantially stagnant layer adjacent the bottom surface, thus increasing the flow of cool cooling liquid along the bottom surface, which results in an improved cooling rate compared to the cooling rate achieved by a substantially linear flow path. Advantageously, the housing with the hollow space can be manufactured as a standard piece, while the insert can be specifically designed for a particular lay-out and cooling requirements of an IGBT. Furthermore, the IGBT itself can be manufactured and/or bought in with a standard base plate.

[0007] In an embodiment, at least one of the one or more elements extends from the flat surface towards the mounting surface and comprises a longitudinal surface or surface section which is non- parallel to the substantially linear path between the inlet and outlet. The non-parallel surface diverts the flow path of the cooling liquid away from the most direct to move such that it is at least partially replaced by cooler cooling liquid flowing from the inlet.

[0008] In an embodiment, the longitudinal surface or surface section is at a 30° to 90° angle with respect to the linear path between the inlet and the outlet. The angle or angles of at least one of the one or more elements are determined by particular cooling requirements of the IGBT module. Said surface sections divert the flow of cooling liquid in predefined directions, away from the linear path between the inlet and the outlet, thereby increasing the amount of cool cooling liquid being distributed over a larger surface area of the base plate and/or increasing the flow rate of cool cooling liquid along said surface area.

[0009] In an embodiment, a surface of the insert facing the mounting surface comprises a plurality of ridges extending substantially perpendicular to the linear flow path between the inlet and the outlet, which ridges, when the insulated-gate bipolar transistor module cooling system is installed, are at a predefined non-zero distance from the base-plate. The ridges disturb the flow of cooling liquid, causing an increase in turbulence in the cooling liquid passing between the ridges and the base plate. This turbulence prevents a substantially stagnant layer of liquid forming adjacent the bottom plate of the IGBT, improving contact between cooler cooling liquid and said botiom plate.

[0010] The plurality of ridges may be tooth-shaped. The sloping edges of the tooth-shaped ridges ensure the turbulent flow is directed towards the outlet, thereby causing a lower pressure drop between inlet and outlet than if the ridges are completely perpendicular to the linear flow between inlet and outlet.

[0011] In an embodiment, the at least one of the one or more elements extending from the flat 40 surface towards the mounting surface form a labyrinth shaped flow path between the inlet and the

P6091353NL { -3- outlet. The cooling fluid is lead along over the entire surface of the base plate, ensuring every part of the base plate is reached by cool fluid — substantially equal cooling rate over entire surface.

[0012] In an embodiment, the insert ís shaped to divide the hollow space into at least two chambers of which a first chamber abuts the through opening in the mounting surface and of which a second chamber is positioned below the first chamber, opposite from the mounting surface, with the first chamber being closed off from the inlet and the second chamber being closed off form the outlet, and wherein at least one of the one or more elements is a plurality of through-holes in the flat surface for passing the flow of cooling liquid between the first and second chambers. The plurality of through-holes leads the flow of cooling liquid from the second chamber, which is connected to the inlet, into the first chamber, dividing the incoming cool flow of cooling liquid more equally over the surface area of the base plate and through the upwards stream causing turbulence in the layer of cooling liquid directly adjacent said base plate.

[0013] In a preferred embodiment, a circumferential side surface of the through-hole is morphed into a nozzle which extends away from the through opening in the mounting surface forming a passage between the first and second chambers. The nozzles cause an increase in flow rate between the second and the first chambers, increasing turbulence adjacent the base plate and therefore increasing the cooling rate.

[0014] In a further embodiment, a third chamber is formed in the insert extending parallel to and in between the first and second chambers, which third chamber is in direct fluid connection to the outlet and via at least one through-hole in fluid connection with the first chamber.

[0015] The flow path is from the inlet, via the second chamber through the nozzles into the first chamber where it cools the base plate and via the through-holes into the third chamber where it exists the cooling system via the outlet. Turbulence is shielded from both the inlet and the outlet, reducing the pressure drop experienced there between by the system.

[0016] In an embodiment, the insert is made of thermally non-conductive or low-conductive material. The insert can be made of relatively light and cheap material such as plastics, which are easy to manufacture to any desired shape. This is possible, since the insert itself merely functions to direct the flow of cooling liquid, rather than having a cooling function itself. The only requirement to the material used for the insert is that it is compatible with the cooling liquid used.

[0017] According to a second aspect of the invention, a method for mounting an IGBT module onto an IGBT module cooling system according to the first aspect of the invention is provided, comprising the step of providing foam-in-place on the mounting surface around the circumference of the through opening to the hollow space prior to mounting a base plate of the IGBT thereon.

[0018] When using a foam-in-place, the housing does not need to be provided with a profile around the through-opening for receiving a packing therein. Using a foam-in-place to seal off the through- opening of the housing against the base plate of the IGBT module thus further reduces the amount of manufacturing steps required for the IGBT module cooling system. Said foam-in-place can be applied by a machine prior to bolting the module onto the housing, automatically filling any holes there between and hardening into a seal-in-place.

P6091353NL { 4-

[0019] According to a third aspect of the invention, a method of manufacturing an IGBT module cooling system is provided, comprising the steps of: providing a housing having an opening in a mounting surface for mounting a base plate of an IGBT module thereon, said opening extending inward to define a hollow space for cooling liquid; providing an inlet and an outlet positioned oposite one another in sidesurfaces of said container shaped element; and providing an insert comprising a flat surface having a circumference matching the opening in the mounting surface and inserting said insert into the housing via the opening such that the flat surface is parallel to the mounting surface, wherein the insert comprises one or more elements adapted to divert a flow of cooling liquid from a substantially linear path between the inlet and the outlet.

[0020] In an embodiment, the step of providing the housing comprises providing an aluminium block and milling said block to provide the opening extending into said hollow space therein. Milling of aluminium blocks is a relatively easy and cheap production method, for example compared to casting, resulting in a housing with high tolerances. Further, by milling the housing out of a block, substantially homogeneous material properties are maintained in the housing, such that the housing maintains its shape well under temperature changes.

[0021] In an embodiment, the step of providing the insert comprises 3D-printing or injection moulding the insert.

Brief description of the drawings

[0022] Embodiments of an IGBT module cooling system according to the present invention will be described by way of example, with reference to the attached drawings, in which:

[0023] Fig. 1 shows a cross-sectional view of an IGBT module with cooling system according to an embodiment;

[0024] Fig. 2 shows a perspective view of the housing for the IGBT module cooling system shown in Fig. 1;

[0025] Fig. 3 shows a perspective view of an insert resulting in a single channel flow path in the cooling system;

[0026] Figs. 4 A and B respectively show a perspective and a side view of the insert shown in the cross-sectional view in Fig. 1, the insert resulting in a more turbulent single channel flow path in the cooling system.

[0027] Figs. 5 A, B, C and D respectively show an exploded view, a top and bottom view of an upper section and a cross-sectional view of an insert 50” having a labyrinth shape.

[0028] Figs. 6 A and B respectively show an exploded view and a cross-sectional view of an alternative insert with multiple flow paths which are perpendicular to the IGBT module. Description of embodiments

[0029] Fig. 1 shows a cross-sectional view of an IGBT module with cooling system according to an embodiment, comprising the IGBT module 10, a housing 100 with a hollow space, and an insert 50 located inside the hollow space. The housing is shaped as a substantially rectangular box, with one outer surface being adapted as a mounting surface 105 for the IGBT module. This mounting surface 105 has a through opening to the hollow space inside the housing 100. The IGBT module

P6091353NL { -5- 10 is mounted onto the mounting surface 105 such that a base plate 1 of the IGBT module closes off the through opening in said mounting surface 105. The housing is provided with an inlet 102 in a first side surface 106 and with an outlet in a second side surface 107, which is opposite the first side surface 106 such that the insert 50 located in the hollow space is in between the inlet 102 and the outlet 104. Further details regarding the housing are discussed in reference to Fig. 2. The insert 50 is shaped to form a partial blockage of the hollow space, preventing a direct linear flow path of cooling liquid between the inlet 102 and the outlet 104. The depicted insert 50 forces an incoming flow of cooling liquid from the inlet 102 upwards towards the base plate 1 of the IGBT module, where, due to the height of the insert 50, the remaining height of the hollow space is narrow such that a relatively high flow rate of cool cooling liquid directly adjacent the base plate 1 is accomplished. Forcing the flow of cooling liquid to change course results in turbulence. Turbulence is advantageous, as this increases mixing of the liquid, thereby maintaining a lower temperature of the liquid directly adjacent the base plate, improving cooling capacity. At the other side of the base plate, the insert 50 slopes downwards, leading the flow into the outlet 104 of the housing. The insert 50 can have various shapes to accomplish improved spreading of cool cooling liquid over the surface area of the base plate 1 and causing a turbulent layer adjacent said base plate 1. Some possible embodiments of the insert 50 are discussed further in reference to Figs. 3 to 6.

[0030] Fig. 2 shows a perspective view of the housing 100 of the IGBT module cooling system of Fig. 1. As can be seen, the surface area of the through opening in the mounting surface 105 corresponds to cross-sectional areas of the hollow space parallel there to, up to and including a surface area of a bottom surface 120 of the hollow space. Thus the length L1 and width W1 of the hollow space is constant along the height H1 of the hollow space and equal to the length and width of the through opening in the mounting surface 105. Furthermore, the inlet 102 and outlet 104, which are provided in opposing side surfaces 107, 108 of the hollow space, are directly opposite one another such that they have a common central axis ¢. The height H2 of the top of the inlet 102 and outlet 104 with respect to the bottom 120 of the hollow space is smaller than the total height H1 of the hollow space, ensuring that after placement of the insert onto the bottom surface 120 of the hollow space no direct linear flow path between the inlet 102 and outlet 104 exists. The configuration of the hollow space, inlet 102 and outlet 104 ensures that the housing 100 can be manufactured with only a few manufacturing steps. The housing 100 is preferably made from a block of metallic material such as for example aluminium or magnesium, wherein the hollow space and through opening are provided in a first machining step by milling or drilling into a side forming the mounting surface 105 and the inlet 102 and outlet 104 may be provided in a second machining step by milling or drilling into a second side, which is perpendicular to the first side. The inlet 104 and outlet 104 can also be manufactured in two separate manufacturing steps, machining the block from two opposite sides to first provide a first and then provide a second of the inlet 102 and outlet

104.

[0031] The housing 100 is further shown to comprise bolt holes 110 and a recess 108 enclosing the through opening in the mounting surface 105. These are optional features, which may be 40 provided in additional machining steps. The bolt holes 110 allow for the IGBT module being bolted

P6091353NL { -&- onto the housing 100. Alternatively the IGBT module could be adhered or clamped onto the housing, such that the bolt holes 110 are not required. The recess 108 enclosing the through opening may be provided with an O-ring, closing off the hollow space in a liquid proof manner when the IGBT module is mounted onto the housing 100. Alternatively, instead of the recess 108 holding the O- ring, a foam-in-place can be used to ensure liquid proof closing of the through opening to the hollow space by the IGBT module. If foam-in-place is used, no additional machining step is required to be performed on the housing for providing the recess.

[0032] Fig. 3 shows a perspective view of an insert 50’ resulting in a single channel flow path in the cooling system. The insert 50’ has a rectangular shaped flat surface 60’ defining a bottom side, having a length L and width W matching the length L1 and width W1 of the hollow space of the housing 100. Through this shape, the insert can easily be inserted into the hollow space via the through opening, whilst the matching length L1 and width W1 ensure that the position of the insert on the bottom of the hollow space is maintained. Both longitudinal ends of the insert 50" are wedge shaped, with surfaces 61’ extending upwards from the flat surface 60’ at an angle a, such that an upper surface 62’ of the insert 50’ has an equal width W to the bottom side, but is shorter in length. The height h of the insert 50” is shorter than the height H1 of the hollow space, such that a predetermined thickness of cooling liquid flows adjacent the base plate during use. Furthermore, the height h of the insert 50’ is preferably equal or larger than the height H2 of the upper side of the inlet 102 and outlet 104 with respect to the bottom 120 of the hollow space onto which the insert 50’ rests during use. This ensures the full flow of cooling liquid, exiting the inlet 102 parallel to its central axis c is diverted by the insert due to surface 61’ blocking the linear path. The angle a of the surface 61" with respect to the flat surface 60’ is preferably between 45° and 70°, and is more preferably around 680°, such that the diverted cooling liquid flows past as much of the base plate 1 as possible without resulting in too much pressure loss along the flow path.

[0033] Since the insert 50’ merely functions to direct the flow of cooling liquid, the insert 50’ is not required to transfer any heat from the IGBT. As a result, the insert 50’ may be manufactured from a relatively easy and cheap material which can be moulded or 3D printed, such as for example thermoset plastics.

[0034] Figs. 4 A and B respectively show a perspective and a side view of the insert 50 shown in the cross-sectional view in Fig. 1. This insert 50’ is similar in shape and features to the insert 50’ shown in Fig. 3, except that the upper surface 62 is provided with a plurality of equally spaced tooth- shaped ridges extending in the width-direction thereof. The tooth-shaped ridges are thus placed perpendicular to the direction of the flow of cooling liquid over the insert 50, when in use. A first side of each of the tooth-shaped ridges, at the inlet side of each ridge, is extending vertically upwards from the upper surface 62, while a second side of each ridge, at the outlet side, is positioned at an angle. Each of the toothed shaped ridges forces a lower part of the flow of cooling liquid upwards, resulting in a substantially continuous increased turbulence in the flow of cooling liquid over the insert, homogenizing the {cooler) temperature of the cooling liquid contacting the base plate 1.

[0035] Figs. 5 A, B, C and D respectively show an exploded view, a top and a bottom view of an 40 upper section and a cross-sectional view of an insert 50” having a labyrinth shape. Different from

P6091353NL { -7- the previously discussed inserts, and as shown in Fig. 5A, the insert 50” consists of two sections, an upper section 50a” and a lower section 50b”. Both sections 50a” and 50b” have a rectangular outer circumference with length L and width W, which is substantially constant over the height h” of the insert.

[0036] The upper section 50a” has a flat surface 60a”, wall parts 61a”, 61b”, 61c”, wall elements 65”, through-holes 55", 56” and a recessed lower edge 54”. The flat surface 60a” is provided with an upstanding outer wall which forms the outer circumference of the upper section and comprises the front and aft wall parts 61a”, 61c¢”, arranged in the width direction of the insert. Additional wall part 61b” is placed perpendicular to and in between the front and aft wall parts 61a”, 61c”, interconnected the longitudinal wall parts of the outer wall such that the outer wall and the additional wall part define a front and an aft first chamber 71a”, 71b”. The wall parts 61a”, 61b”, 61¢” are placed perpendicular to the linear flow direction between inlet and outlet, disrupting any linear flow path along the full length of the upper side of the insert 50”. Inside each chamber, wall elements 65” are placed with equal spacing, extending in the longitudinal direction of the insert 507, alternatingly starting from one of the front/aft wall part 61a”; 61¢” and the additional wall part 61b” and ending at a predefined distance from the other thereof, thereby forming a labyrinth in each of the front and an aft first chambers 71a”, 71b”". Both the front and the aft first chambers 71a”, 71b” are provided with a first through-hole 55" at an outer end of the labyrinth nearest the inlet side of the insert, for serving as an inlet into the labyrinth, and a second through-hole 56” at an outer end of the labyrinth nearest the outlet side of the insert, for serving as an outlet from the labyrinth. The recessed lower edge 54” allows the upper section 50a” to be placed interlocking onto the lower section 50b”. The interlocking position may be made permanent through for example an adhesive.

[0037] The lower section 50b” has a flat surface 60b”, an outer wall with an additional inner wall part 61d”, an inlet 52” and an outlet 53”. The flat surface 60b” is provided with the outer wall around its circumference, said outer wall extending upwards from the flat surface 60b”. The inlet 52” is provided as an opening in the wall in the center of the front wall part and the outlet 53” is provided as an opening in the wall in the center of the aft wall part, such that the inlet 52” and outlet 53” line up with the inlet and outlet of the housing when the insert is located therein. The additional wall part 61d” extends substantially in the longitudinal direction of the bottom section 50b” and connects diagonally opposing wall parts adjacent the inlet and the outlet. When the upper and lower sections 50a” and 50b” are assembled, the additional wall part 61d” divides the lower section 50b” into two chambers, such that a second chamber 72” is formed which is closed off from the outlet 53” and a third chamber 73” is formed which is closed off from the inlet 52".

[0038] In use, the cooling liquid flows from the inlet 52" into the second chamber 72”, from where the flow enters the front and aft first chambers 71a”, 71b” via the first through-holes 55" at approximately the same temperature. Within both first chambers 71a”, 71b” a part of the cooling liquid is forced to follow the labyrinth towards the second through holes 56”, while another part of the cooling liquid flows over the wall elements 65” in a turbulent flow pattern caused by the wall elements 65” being substantially perpendicular to the direction of flow. This results in the cooling 40 liquid being distributed along the entire surface of the base plate adjacent the first chamber 71a”;

P6091353NL { -8- 71b” via the labyrinth, whilst simultaneously ensuring that relatively cool cooling liquid replaces warmed up cooling liquid adjacent the base plate rapidly. The second through-holes 56” lead the flow from both first chambers 71a”, 71b” into the third chamber 73”, from where the flow exits the via the outlet 53”.

[0039] Figs. 6 A and B respectively show an exploded view and a cross-sectional view of an alternative insert 50” defining multiple flow paths which are perpendicular to the IGBT module. Similar to the previously shown insert 50”, this insert 50” consists of two sections, an upper section 50a” and a lower section 50b’”. The upper section 50a” has a flat surface 60a", through-holes 55a”, 56", nozzles 57°" and inlet wall part 52a". The through-holes 55a”, 56" are provided in the flat surface 60a’, with a first of the through-holes 55a’ being extended downwards into nozzles which are evenly distributed over the flat surface 60a". The lower section 50b™ has a flat surface 60b””, through-holes 55b™, inlet opening 52b™, outlet wall part 53" and a plurality of spacers 58". The through-holes 55b™ are provided in the flat surface 60b””, in a pattern matching the distribution of the nozzles 57°” of the upper section 50a”. The nozzles 57" each have a recess 54" at their free end, which recess fits into the through-hole 55b™ of the lower section 60b’” when the upper and lower sections 50a”, 50b’” are joined up to form the inset 50”. The upper section 50a” is on a first longitudinal end provided with a downward extending, half-dome shaped wall forming the inlet wall-part 52a”. Said inlet wall-part 52a" has a lower edge which matches an outer edge of the inlet opening 52b" of the lower section 50b*”” which is provided on the same longitudinal end of said lower section 50b”. The lower section 50b” is at the opposite longitudinal end provided with another downward extending, half-dome shaped wall, which forms the outlet wall-part 53". The lower section 50b’” is provided with the plurality of spacers extending from a bottom side of the flat surface 60D’”, for providing a clearance between said flat surface 60b™ and the bottom surface 120 of the hollow space in the housing when in use.

[0040] The length of the spacers 58” and the nozzles 57°” is such that a total height h™” of the insert 50”, when upper and lower sections are assembled, is smaller than the height H1 of the hollow space, subdividing the hollow space in the housing into three chambers 71, 727°, 73”. The first chamber 71” is located adjacent the base plate of the IGBT, with the flat surface 60a” of the upper section of the insert 50” defining the lower surface thereof. The second chamber 72” is located adjacent the bottom surface 120 of the hollow space, with the flat surface 60b™ of the lower section of the insert 50" defining the upper surface thereof being kept at distance from the bottom surface 120 by the spacers 58”. The third chamber 73" Is located in between the first and second chambers, with the flat surfaces 60a’, 60b™ of the insert defining both the upper and lower surfaces thereof and a spacing between both flat surfaces being maintained by the nozzles 57”. The inlet wall-part 52a” and inlet opening 52b™ direct an incoming flow of cooling liquid from the inlet into the second chamber 72%”. Said second chamber 72” is blocked from the outlet by the outlet wall- part 53”, such that the cooling liquid can only exit the chamber via the openings 55b””, which are connected to the nozzles 57°, ensuring the cooling liquid flows upwards into the first chamber via openings 55a”. Through the distribution of the openings 55a””, 55b™, the cooling liquid is evenly 40 distributed at substantially the same cool temperature over the base plate. The cooling liquid is

P6091353NL { -9- directly aimed at the base plate through the upward flow from the nozzles 57”, preventing the formation of any stagnant layer adjacent the base plate and causing the flow within the first chamber 71” to be turbulent over the entire chamber. The flow of cooling liquid exits the first chamber 71” via a second of the through-holes 56” in the flat surface 60a" of the upper section 50a™, into the third chamber 73”. The outlet wall part 53” of the lower section 50b™ enables the flow of cooling liquid to exit the hollow space through the outlet from the third chamber 73”.

[0041] The inserts 50", 50” may be produced in two parts, as shown in Figs. 5A and 6A, which are assembled into a single insert prior to inserting the insert into the housing. Alternative production techniques may allow the inserts being produced as single pieces.

[0042] The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.

Claims

Conclusions

A cooling system for an insulated gate bipolar transistor (IGBT) module comprising: a housing (100) enclosing a hollow space (120) comprising an inlet (102) and an outlet (104) positioned opposite each other on opposite opposite sides (106, 107) of the housing for the flow of cooling liquid through the hollow space (120) from the inlet (102) to the outlet (104), and a mounting surface (105) for mounting a base plate (10) thereon 1) of the IGBT module (10) positioned parallel to the inlet (102) and outlet (104), and including a passage to the cavity that allows coolant in the cavity to directly contact the base plate (1) of the IGBT module (10), wherein cross-sections of the cavity (120) parallel to the via are substantially equal in size and shape to the via, and wherein an insert (50; 50°; 50”; 50') is provided in the hollow space (120), comprising a flat surface (60; 60'; 60”; 60") whose shape conforms to the passageway and is positioned substantially parallel to the mounting surface (105) at a predetermined distance therefrom, the insert further comprising one or more elements (61, 65; 61'; 61a”, 61b” , 81c", 55", 55", 56°", 57”) adapted to divert the flow of coolant from a substantially linear path between the inlet (102) and the outlet (104).

The cooling system for an IGBT module according to claim 1, wherein at least one of the one or more elements extends from the flat surface (60; 80; 60"; 60") to the mounting surface and a longitudinal surface or surface section (61, 65; 61'; 61a", 61b", 61°", 57") that is not parallel to the substantially linear path between the inlet (102) and outlet (104).

The cooling system for an IGBT module according to claim 2, wherein the longitudinal surface or the surface section is at an angle of 30° to 90° with respect to the linear path between the inlet and the outlet.

The cooling system for an IGBT module according to claim 2 or 3, wherein a surface of the insert facing the mounting surface includes a plurality of cams (65; 61a", 61b", 610") extending substantially perpendicular to the linear path between the inlet and the outlet, which cams are at a predetermined non-zero distance from the base plate, when the cooling system for the insulated gate bipolar transistor module is installed.

The cooling system for an IGBT module according to claim 4, wherein the plurality of cams (65) have a tooth profile.

The cooling system for an IGBT module according to any one of claims 2 to 4, wherein the at least one of the one or more elements (65") extending from the flat surface (60") to the mounting surface (105) has a labyrinthine flow path forms between the inlet and the outlet.

The cooling system for an IGBT module according to any one of the preceding claims, wherein the insert is formed to divide the cavity into at least two chambers, a first chamber adjoining the passageway in the mounting surface and the second chamber below the first chamber is positioned opposite the mounting surface, the first chamber being sealed from the inlet and the second chamber being sealed from the outlet, and at least one of the one or more elements has a plurality of passages (55", 56", 55 ™) is in the flat surface (80”, 60°”) for the flow of cooling liquid to pass between the first and second chambers.

The cooling system for an IGBT module according to claim 7, wherein a circumferential side surface of the passageway merges into a nozzle (57) extending from the passageway into the mounting surface (105) and forming a passageway between the first and second chambers.

The cooling system for an IGBT module according to claim 8, wherein a third chamber is formed in the insert extending parallel to and between the first and second chambers, the third chamber being in direct fluid communication with the outlet and through at least one passageway (58°”) is in fluid communication with the first chamber.

The cooling system for an IGBT module according to any one of the preceding claims, wherein the insert (50; 50'; 50"; 50") is made of thermally non-conductive or poorly conductive material.

A method of mounting an IGBT module (10) to an IGBT module cooling system according to any preceding claim, comprising the step of providing in-situ foams on the mounting surface (105) around the perimeter of the passage to the hollow space (120) before mounting a base plate (1) of the IGBT thereon.

A method of producing a cooling system for an IGBT module, comprising: providing a housing having an opening in a mounting surface for mounting a base plate of the IGBT module thereon, the opening extending inwardly to provide a define hollow space for coolant; providing an inlet and an outlet positioned opposite each other in side surfaces of the container-shaped member; and providing an insert comprising a flat surface having a contour that conforms to the opening in the mounting surface and positioning the insert into the housing through the opening so that the flat surface is parallel to the mounting surface, the insert comprising one or more elements adapted to divert a flow of coolant from a substantially linear path between the inlet and outlet.

The method of claim 13, wherein the step of providing the housing includes providing an aluminum block and milling the block to provide the opening extending into the hollow space therein.

The method of claim 12 or 13, wherein the step of providing the insert comprises 3D printing or injection molding the insert.

Assembly of an IGBT module and cooling system of an IGBT module according to one of claims 1-10 or cooling system of an IGBT module produced according to the method according to one of claims 12-14.