Patent ID: 12238903

MODE FOR INVENTION

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. The following embodiments may be modified in various forms, and the scope of the present invention is not limited to the following embodiments. The embodiments are provided to make the present invention more thorough and complete, and to completely convey the spirit of the present invention to those skilled in the art. In addition, a thickness or size of each layer illustrated in the drawings is exaggerated for the purpose of clarity and for convenience of description.

Hereinafter, the embodiments of the present invention will be described with reference to the drawings that schematically illustrate ideal embodiments of the present invention. In the drawings, for example, depending on manufacturing techniques and/or tolerance, variations of the illustrated shape may be expected. Therefore, it should be interpreted that the embodiments based on the spirit of the present invention are not limited to particular shapes of regions illustrated in the present specification but include changes in shapes made during a manufacturing procedure, for example.

FIG.1is a perspective view schematically illustrating a water-cooled heat dissipation module assembly100according to an embodiment of the present invention,FIG.2is a perspective view schematically illustrating a cross-section taken along line A-A inFIG.1,FIGS.3and4are cross-sectional views illustrating a process of joining a housing unit10and a cooling unit20at a portion inFIG.2, andFIG.5is a cross-sectional view illustrating another embodiment of the housing unit10and the junction part of the cooling unit20inFIG.2.

First, as illustrated inFIG.1, a water-cooled heat dissipation module assembly100according to an embodiment of the present invention may broadly include a housing unit10and a cooling unit20.

As illustrated inFIG.1, the housing unit10is provided in the form of a housing having an opening portion11at least partially opened at one side thereof and has a flow space in which a coolant may flow. A coolant inlet port12may be formed at one side of the housing unit10, and a coolant discharge port13may be formed at the other side of the housing unit10, such that the coolant may be introduced into or discharged from the flow space.

In addition, the cooling unit20is provided in the form of a plate and coupled to the opening portion11of the housing unit10so as to close the opening portion11of the housing unit10, which is opened at one side thereof, and seal the flow space from the outside. A plurality of cooling fins is formed on one surface of the housing unit10that is directed toward the flow space, such that a power module M attached to the other surface of a region in which the plurality of cooling fins is formed may be cooled.

For example, the cooling unit20may be coupled to the housing unit10so that one surface on which the plurality of cooling fins is formed is directed toward the flow space. Therefore, the plurality of cooling fins formed on the cooling unit20may exchange heat with the coolant, which flows in the flow space of the housing unit10, while coming into direct contact with the coolant, such that the power module M, which is attached to the other surface of the region in which the plurality of cooling fins of the cooling unit20is formed may be cooled.

In addition, although not illustrated, a thermal grease layer may be formed between contact surfaces of the cooling unit20and the power module M and formed by applying thermal grease. The thermal grease layer may fill a fine gap between the cooling unit20and the power module M to facilitate heat transfer and improve cooling characteristics.

As described above, the power module M is cooled by the cooling operation, i.e., the heat exchange between the coolant flowing in the flow space of the housing unit10and the plurality of cooling fins of the cooling unit20. The power module M is typically called a power semiconductor module and has an insulated gate bipolar transistor (IGBT), a MOSFET, a bipolar transistor, or the like. The power module M may be configured by disposing a DBC (direct bonded copper) substrate on an upper surface of a base plate and attaching a semiconductor chip to the DBC substrate.

The entire portion of the housing unit10and at least a part of a rim region of the cooling unit20may be made of a plastic material so that the housing unit10and the cooling unit20may be joined by plastic welding using a laser.

For example, as illustrated inFIGS.1and2, the housing unit10may be made of an impermeable plastic material. In addition, the cooling unit20is provided in the form of a plate corresponding to a shape of the opening portion11of the housing unit10. The plurality of cooling fins is formed on one surface of the housing unit10that is directed toward the flow space. The cooling unit20may include a junction part22formed at a position corresponding to a periphery of a cooling plate21made of a metallic material, as a whole, and to a periphery of the opening portion11of the housing unit10. The junction part is formed along a rim portion21aof the cooling plate21while surrounding at least a part of the rim portion21aof the cooling plate21, and the junction part is made of a permeable plastic material.

More specifically, the cooling plate21of the cooling unit20, on which the plurality of cooling fins is formed, may be made of copper having high thermal conductivity so that the coolant flowing in the flow space of the housing unit10may smoothly exchange heat with the power module M. However, the material of the cooling plate21is not necessarily limited to copper. All the metallic materials, such as aluminum, magnesium, or steel, which may induce thermal conduction, may be applied.

In addition, the junction part22between the housing unit10and the cooling unit20, which is made of a plastic material, may be made of engineering plastic (EP), which is a high-performance plastic material that has excellent strength and elasticity and may withstand even a high-temperature condition, so that the engineering plastic may be substituted for a metallic material such as aluminum in the related art. More particularly, the junction part may be made of super engineering plastic having a working temperature of 150° C. or more in order to prevent deformation and damage caused by the coolant with a raised temperature during the process of cooling the power module M.

Therefore, the housing unit10may be manufactured by a plastic injection molding process, and the junction part22of the cooling unit20may be manufactured by a plastic insert injection molding process.

In addition, as illustrated inFIG.1, in the housing unit10, a first connector N1having a nipple shape is provided on the coolant inlet port12to connect the coolant inlet port12and a coolant tube for supplying the coolant, and a second connector N2having a nipple shape is provided on the coolant discharge port13to connect the coolant discharge port13and a coolant tube for discharging the coolant. The first connector N1and the second connector N2are also made of a plastic material identical to the material of the housing unit10, such that the first connector N1and the second connector N2may be integrated with the housing unit10during the process of manufacturing the housing unit10by injection molding.

Further, as illustrated inFIGS.2and4, in the present embodiment, an example is described in which the junction part22of the cooling unit20formed by the insert injection molding process is formed to surround only at least a part of the rim portion21aof the cooling plate21. However, the present invention is not limited thereto. As illustrated inFIG.5, the cooling plate21has an insert groove portion21bformed on at least one of one surface, on which the plurality of cooling fins is formed, and the other surface opposite to one surface. The insert groove portion21bis concavely formed in a portion surrounded by the junction part22along the rim portion21aof the cooling plate21. The junction part22has an insert coupling portion22bprotruding along the insert groove portion21band having a shape corresponding to the insert groove portion21b. The junction part22of the cooling unit20may surround the rim portion21aof the cooling plate21while engaging with the rim portion21aof the cooling plate21.

As described above, because the junction part22of the cooling unit20surrounds the rim portion21aof the cooling plate21while engaging with the rim portion21aof the cooling plate21by means of the insert groove portion21band the insert coupling portion22b, it is possible to further increase a coupling force between the cooling plate21of the cooling unit20and the junction part22formed by insert injection molding.

A structure and process for joining the housing unit10and the cooling unit20by plastic welding using a laser will be described more specifically. As illustrated inFIG.3, the housing unit10includes a junction protrusion portion10aprotruding in a ring shape along a periphery of the opening portion11. The junction part22of the cooling unit20may include a junction groove portion22aconcavely formed in a ring shape at a position corresponding to the junction protrusion portion10aso that the junction groove portion22amay accommodate at least a part of the junction protrusion portion10a. In this case, the junction protrusion portion10amay have a thickness T smaller than a width W of the junction groove portion22aand have a height H larger than a depth D of the junction groove portion22a.

Therefore, as illustrated inFIG.3, when the cooling unit20is seated on the housing unit10so that the junction protrusion portion10aand the junction groove portion22aare matched with each other in shape, the cooling unit20may be seated in a state of being slightly spaced apart from the housing unit10because of the junction protrusion portion10ahaving the height H larger than the depth D of the junction groove portion22a. In addition, empty spaces may be defined at two opposite sides of the junction groove portion22abecause of the junction protrusion portion10ahaving the thickness T smaller than the width W of the junction groove portion22a. In this case, a gap between the housing unit10and the cooling unit20and an empty space of the junction groove portion22a, which are illustrated inFIG.3, are exaggerated to assist in understanding the invention. However, actually, a very fine gap and a very small space may be provided.

Therefore, as illustrated inFIG.3, when laser beams L are emitted from a laser welding device (not illustrated) to the portion where the junction protrusion portion10aand the junction groove portion22aare matched with each other in shape, the junction protrusion portion10ais melted, and the empty spaces of the junction groove portion22aare filled with the molten junction protrusion portion10a, such that the housing unit10and the junction part22of the cooling unit20may be joined to each other, as illustrated inFIG.4.

More specifically, as illustrated inFIG.3, the junction part22of the cooling unit20, which has the junction groove portion22a, is formed as a transmission layer that is made of a permeable plastic material and transmits the laser beam L. The housing unit10having the junction protrusion portion10ais formed as an absorption layer that is made of an impermeable plastic material and absorbs the laser beams L emitted from the laser welding device. In this state, when the laser welding device emits the laser beams L to the portion where the junction protrusion portion10aand the junction groove portion22aare matched with each other in shape, the laser beams L may pass through the junction part22of the cooling unit20, which is the transmission layer, and energy of the laser beams L may be absorbed by the junction protrusion portion10aof the housing unit10that is the absorption layer.

Therefore, the junction protrusion portion10aof the housing unit10, which absorbs energy of the laser beams L, generates heat, the junction protrusion portion10ais melted by the generated heat, the empty spaces of the junction groove portion22aof the junction part22are filled with the junction protrusion portion10a, and then the junction protrusion portion10ais cured, such that the housing unit10and the junction part22of the cooling unit20may be joined to each other.

During the plastic laser welding process, the housing unit10and the junction part22of the cooling unit20may be compressed at a predetermined pressure by a compression device so that at least a part of the junction groove portion22a, which is brought into contact with the junction protrusion portion10aby heat generated and transferred from the junction protrusion portion10a, may also be melted together with the junction protrusion portion10aand then joined to the junction protrusion portion10a.

During the above-mentioned process, the junction protrusion portion10aand at least a part of the junction groove portion22a, which comes into contact with the junction protrusion portion10a, are melted together, such that the housing unit10and the junction part22of the cooling unit20may be joined to each other as the empty spaces of the junction groove portion22aare filled with the molten material, as illustrated inFIG.4.

In this case, the gap, which is formed between the junction part22of the cooling unit20and the housing unit10because of the junction protrusion portion10ahaving the height H larger than the depth D of the junction groove portion22a, may disappear as the junction part22of the cooling unit20and the housing unit10are brought into close contact with each other because the height H is decreased as the junction protrusion portion10ais melted and because of the pressure applied by the compression device.

In addition, the melted plastic material needs to be completely cured to implement permanent coupling between the housing unit10and the junction part22of the cooling unit20. Therefore, the compressed state between the housing unit10and the junction part22of the cooling unit20may be maintained for a predetermined time by the compression device even after the welding process using the laser beams L has ended.

As described above, the housing unit10made of an impermeable and the junction part22of the cooling unit20made of a permeable thermoplastic plastic are joined to each other by plastic laser welding performed by emitting the laser beam L, a junction between the housing unit10and the junction part22of the cooling unit20may be finished with high quality. Further, a junction, which is formed by melting the junction protrusion portion10aand at least a part of the junction groove portion22athat is in contact with the junction protrusion portion10a, may be more securely formed while having strength equal to strength of an original material.

In addition, in the above-mentioned embodiment, as illustrated inFIG.1, the example of the water-cooled heat dissipation module assembly100has been described in which the coolant inlet port12and the coolant discharge port13are formed at one side and the other side of the housing unit10while facing each other, the housing unit10has a flat shape, and a micro-channel is formed in the flow space in which the coolant flows. However, the shape of the housing unit10is not necessarily limited thereto. The housing unit10may be formed to be high in a height direction, the coolant inlet port12and the coolant discharge port13may be formed side by side at one side of the housing unit10. In addition, various shapes of the housing unit10may be applied in accordance with the type of vehicles and the necessary cooling specifications.

Therefore, according to the water-cooled heat dissipation module assemblies100and200according to the embodiments of the present invention, a part of the cooling unit20is made of a plastic material, except for all the parts of the housing unit10and the portion where the plurality of cooling fins, which exchanges heat with the coolant, is formed. Because most of the components are made of a nonmetallic material, the weight of the product may be reduced, and energy efficiency of vehicles to which the product is applied may be improved.

In addition, the housing unit10and the cooling unit20are manufactured by plastic injection molding, which makes it possible to reduce the costs required to manufacture the components. Further, the housing unit and the cooling unit are integrated by being joined to each other by plastic welding using a laser, which makes it possible to improve manufacturability and reduce process costs.

While the present invention has been described with reference to the embodiment illustrated in the drawings, the embodiment is described just for illustration, and those skilled in the art to which the present invention pertains will understand that various modifications of the embodiment and any other embodiment equivalent thereto are available. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.