Power conversion electronic device for an electric or hybrid vehicle

Abstract

Power conversion electronics (1) for an electric or hybrid vehicle, comprising: a printed circuit board (2); a plurality of power components mounted on the printed circuit board (2) and including SMD or PTH top cooled MOSFET devices (3); a sensor device (5) operatively associated with the MOSFET device (3) and adapted to sense a temperature value from the MOSFET device (3); a layer (6) made of an electrically insulating thermally conductive material arranged in contact with each power component; a heat sink body (7) associated with the layer (6) and adapted to dissipate heat generated by said power component; thermal connection means (8) between the MOSFET device (3) and the sensor device (5), comprising at least one pad (9) made of a thermally conductive material, the at least one pad (9) being placed between the MOSFET device (3) and the sensor device (5).

Description

Technical Field

[0001] The present invention relates to a power conversion electronic device. Background Art

[0002] In order to be able to regularly charge the battery, electric vehicles and hybrid vehicles are equipped with special devices (so-called "on-board chargers (OBCs)") that can be connected to an AC power line at the input end and to the vehicle battery at the output end.

[0003] Specifically, known devices are provided with a printed circuit board on which a plurality of power components are mounted. These power components are adapted to convert the input alternating current into a predefined corresponding direct current and deliver the direct current to the battery for storage.

[0004] Among the various power components, such devices include one or more SMD or PTH (through-hole) top-cooled MOSFETs (metal-oxide-semiconductor field-effect transistors), which are composed of special transistors. The heat generated therein is dissipated through a special heat sink, and the position of the heat sink is associated with the printed circuit board and opposite to the part where the MOSFET is located.

[0005] A detail of a known device related to the assembly of the above MOSFET and the associated heat sink is shown by way of example in Figure 1 wherein the device, printed circuit board, and MOSFET specifically considered have been identified with reference letters A, C, and M, respectively.

[0006] The above special arrangement of the heat sink of the MOSFET (metal-oxide-semiconductor field-effect transistor) M makes it completely unnecessary to provide a special insulated metal substrate (IMS) circuit for heat dissipation, thus reducing the overall size of such a device A and its manufacturing complexity.

[0007] In order to enable heat to be discharged outward from the device A, the heat sinks of the respective components are associated with the heat sink D of the device itself, and the heat sink D can be of the type of a liquid cooling circuit.

[0008] However, in order to comply with current safety regulations, proper electrical insulation must be achieved between the heat sink of the component and the heat sink D of the device; for this purpose, the device A provides a gap filler G, which is a single-layered or double-layered structure made of an electrically insulating material with high thermal conductivity.

[0009] In this case, the gap filler G is an elastic double-layered structure adapted to cure after being applied to the power component.

[0010] Therefore, during the assembly process of the device A, the gap filler G can be extruded to assemble the gap filler G between various power components and electrically insulate the various power components.

[0011] In summary, it should be specifically noted here that monitoring the operating temperature of the field - effect transistors M plays an important role in ensuring that no dangerous overheating occurs during the use of device A.

[0012] For this reason, device A includes a plurality of temperature sensors S, each of which is associated with one or more field - effect transistors M and is configured to detect the operating temperature of the one or more field - effect transistors M.

[0013] In the specific case of the known device A under consideration, the temperature sensors S are placed at a minimum distance close to their respective field - effect transistors M; in this way, the gap filler G is installed by its own extrusion between one element and another, and the heat generated by the field - effect transistors M can thus be transferred to the corresponding temperature sensors S.

[0014] Nevertheless, it must be pointed out that the methods discussed so far are not without drawbacks.

[0015] First of all, it should be understood that the size of the temperature sensors S is generally much smaller than the size of the field - effect transistors M, so an excessive amount of gap filler G needs to be provided to ensure that the gap filler G is sufficiently interposed between each field - effect transistor M and the corresponding temperature sensor S.

[0016] However, even when using smaller field - effect transistors M, the accuracy and repeatability of placing the gap filler G between the field - effect transistors M and the temperature sensors S are still very low.

[0017] In this regard, it must actually be taken into account that the extrusion of the gap filler G itself is an operation that is highly inaccurate to perform; this means that even when repeated in a seemingly identical manner, the operation does not always return the same final result.

[0018] It is easy to understand that the lack of repeatability in the industrial production process is a rather inconvenient situation, because in the long run, this may be the cause of uncertainties and problems in the products put on the market.

[0019] Another drawback is that the position of the temperature sensors S causes them to detect not only the temperature of the field - effect transistors M but also the temperature of the radiator D of device A, because as mentioned above, both the radiator D and the field - effect transistors M are thermally connected to the temperature sensors S through the gap filler G. Summary of the Invention

[0020] The main object of the present invention is to design a power conversion electronic device for an electric vehicle or a hybrid vehicle, which is capable of achieving a thermal coupling between a MOSFET and a related temperature sensor, and this thermal coupling is precise and reproducible for all manufactured products.

[0021] Another object of the present invention is to design a power conversion electronic device for an electric vehicle or a hybrid vehicle, which can overcome the above-mentioned disadvantages of the prior art within the framework of a simple, reasonable, easy-to-use and effective, and low-cost solution.

[0022] The above object is achieved by a power conversion electronic device for an electric vehicle or a hybrid vehicle having the features of claim 1. Description of the Drawings

[0023] Other features and advantages of the present invention will become more apparent by describing a preferred but non-exclusive embodiment of the power conversion electronic device for an electric vehicle or a hybrid vehicle, which is illustrated by way of schematic but non-limiting examples in the accompanying drawings, wherein:

[0024] Figure 1 is an overall detailed axonometric view of a known device related to the assembly of an SMD top-cooled MOSFET;

[0025] Figure 2 is an axonometric view of the details of a device according to a first embodiment of the present invention;

[0026] Figure 3 is Figure 2 exploded view of the details of;

[0027] Figure 4 is an axonometric view of the details of a device according to a second embodiment of the present invention;

[0028] Figure 5 is Figure 4 exploded view of the details of;

[0029] Figure 6 is a cross-sectional view of the details of a device according to a third embodiment of the present invention. Detailed Description of the Invention

[0030] Specifically referring to these drawings, reference numeral 1 generally represents a power conversion electronic device for an electric vehicle or a hybrid vehicle.

[0031] The power conversion electronic device 1 for an electric vehicle or a hybrid vehicle can be installed inside at least one electric vehicle or hybrid vehicle and can be connected to at least one battery of the vehicle. The power conversion electronic device 1 includes:

[0032] At least one printed circuit board 2 having at least one first face 2a and at least one second face 2b opposite to each other;

[0033] A plurality of power components configured to convert at least one input current / voltage into at least one predefined output current / voltage for delivery to a battery, the power components being mounted on the printed circuit board 2 and arranged on one of the first face 2a or the second face 2b.

[0034] It should be noted in particular that the power components include at least one SMD or PTH (through-hole) top-cooled MOSFET device 3.

[0035] As described above, the MOSFET device 3 is provided with a special heat dissipation element 4 which is adapted to dissipate the heat generated during the use of the device 1.

[0036] In this regard, the MOSFET device 3 is provided with two reference portions 3a, 3b, wherein the first reference portion 3a faces the printed circuit board 2; the second reference portion 3b is opposite to the first reference portion 3a and faces the opposite side with respect to the printed circuit board 2.

[0037] In this sense, the heat dissipation element 4 is associated with the second reference portion 3b.

[0038] Furthermore, the device 1 includes at least one sensor device 5 which is operatively associated with the MOSFET device 3 and is adapted to sense at least one temperature value therefrom.

[0039] Specifically, the "temperature value" refers to the operating temperature of the MOSFET device 3, that is, the temperature of the MOSFET device 3 during the use of the device 1.

[0040] In fact, the MOSFET device 3 is traversed by a large current, so measuring its operating temperature is crucial for preventing any overheating of the device, in order to prevent damage to the device 1.

[0041] Similarly, the device 1 includes at least one layer of electrically insulating and thermally conductive material layer 6 which is arranged in contact with each power component.

[0042] In fact, the high voltage applied to the power components requires proper electrical insulation of the power components.

[0043] In this regard, the layer 6 is elastically deformable and can thus be squeezed (for example, during the assembly stage of the device 1) to insert itself at least partially between one power component and another power component, so as to electrically insulate the power components.

[0044] Preferably, layer 6 is of the one-component or two-component type and is suitable for curing after being applied to device 1 (referred to as "gap filler" in technical terms).

[0045] Similarly, device 1 includes at least one radiator body 7 (which can be of the type shown in the figure or a water chamber), the radiator body 7 is associated with layer 6 and is suitable for dissipating the heat generated by the power components and removing the heat from the device itself.

[0046] In this regard, it should be noted that layer 6 is provided with at least one first surface 6a facing the MOSFET device 3 and at least one second surface 6b opposite to the first surface 6a.

[0047] In this sense, the radiator body 7 is associated with the second surface 6b.

[0048] According to the present invention, device 1 includes thermal connection means 8 between the MOSFET device 3 and the sensor device 5, the thermal connection means 8 includes at least one pad 9, the pad 9 is made of a thermally conductive material and is placed between the MOSFET device 3 and the sensor device 5.

[0049] The pad 9 is substantially composed of a plate-like element associated with the MOSFET device 3 and the sensor device 5.

[0050] The pad 9 is at least partially made of copper, but it may also be at least partially made of different thermally conductive materials, such as different metal materials (e.g., steel, nickel, etc.), or other thermally conductive materials known to those skilled in the art.

[0051] However, it should be specifically noted that the special means of thermally connecting the MOSFET device 3 to the sensor device 5 through the pad 9 can achieve significant technical advantages, which will be elaborated below and in the remaining part of this disclosure, and these advantages make up for the disadvantages of the prior art complained about before.

[0052] First of all, it should be considered that due to this means, the heat transfer from the MOSFET device 3 to the sensor device 5 is completely independent of the presence of layer 6, and thus independent of the proper extrusion of layer 6 between various power components.

[0053] In other words, due to the presence of layer 6 between the MOSFET device 3 and the sensor device 5, heat conduction between one product and another product in a completely reproducible manner is allowed, such as conduction from the MOSFET device 3 to the sensor device 5.

[0054] By the way, the measurement of the sensor device 5 is absolutely accurate because the temperature of the radiator body 7 cannot be detected by the pad 9 in any way, thus avoiding the possibility of obtaining incorrect temperature values.

[0055] In addition, since layer 6 does not intervene in the thermal coupling between MOSFET device 3 and sensor device 5, the dosage of layer 6 does not require any excess. It is easy to understand that this fact will have a very positive impact on reducing the production cost of device 1.

[0056] According to Figure 2 and Figure 3 In the first embodiment of device 1 shown, MOSFET device 3 and sensor device 5 are arranged on the first side 2a of printed circuit board 2, and pad 9 is mounted between MOSFET device 3 and sensor device 5 on the first side 2a.

[0057] In fact, MOSFET device 3 and sensor device 5 are arranged in contact with pad 9, which is placed between the latter and allows heat to be transferred from the former to the latter.

[0058] Pad 9 can be of the type of an external component applied to printed circuit board 2, or it can be obtained directly from the printed circuit board itself.

[0059] It can be seen that MOSFET device 3 and sensor device 5 are arranged side by side on the first side 2a, and MOSFET device 3 and sensor device 5 are close together so that it is sufficient to use a small-sized pad 9 to thermally connect them together.

[0060] Specifically, in this first embodiment, the thermal connection means 8 includes a single pad 9, which is arranged in contact with MOSFET device 3 and sensor device 5 on the first side 2a.

[0061] From what has been described so far, it is clearly understandable that such a first embodiment achieves the above advantages through a simple and practical technical solution, and simplifies the complexity of device 1 while still ensuring effective heat transfer between MOSFET device 3 and sensor device 5.

[0062] It is important to add that the thermal connection means 8 includes at least one thermal connection element 10. The thermal connection element 10 is located between MOSFET device 3 and pad 9 and is adapted to facilitate heat transfer from MOSFET device 3 to pad 9.

[0063] Specifically, in the first embodiment, the thermal connection element 10 is located between MOSFET device 3 and the single pad 9.

[0064] Preferably, the thermal connection element 10 is of the type of thermal conductive paste.

[0065] In this regard, it should be noted that the thermal connection element 10 is applied between pad 9 and MOSFET device 3 in a completely automatic manner during the assembly stage of the respective components, that is, without any intervention by an operator or skilled worker.

[0066] In this sense, after the device 1 is assembled, the MOSFET device 3 presses against the thermal connection element 10, causing the thermal connection element 10 to expand radially, and ensuring proper heat transfer from the MOSFET device 3 to the sensor device 5 through this expansion.

[0067] In fact, after being pressed, the thermal connection element 10 defines a large heat-conducting bearing surface of the MOSFET device 3 on the pad 9, ensuring that for each product, heat transfer from the MOSFET device 3 to the pad 9 occurs in a proper manner.

[0068] Therefore, the special means of providing the thermal connection element 10 in combination with the pad 9 ensures that the thermal coupling between the MOSFET device 3 and the sensor device 5 is absolutely precise and reproducible for all manufactured products.

[0069] Having described this first embodiment, it should be reiterated that arranging the sensor device 5 and the MOSFET device 3 closely adjacent on the first face 2a allows the temperature of the MOSFET device 3 to be measured in an absolutely precise manner.

[0070] However, the above proximity means that the sensor device 5 must also be electrically insulated from the power components through the layer 6.

[0071] In this regard, according to Figure 4 and Figure 5 In the second embodiment shown, the MOSFET device 3 is arranged on the first face 2a and the sensor device 5 is arranged on the second face 2b.

[0072] In fact, in this second embodiment, the MOSFET device 3 and the sensor device 5 are opposite each other on the printed circuit board 2.

[0073] In addition to those already listed, this arrangement of the sensor device 5 also has the additional advantage that electrical insulation of the sensor device 5 is completely unnecessary because in the above second embodiment, the sensor device 5 and the MOSFET device 3 are placed on different faces 2a, 2b of the printed circuit board.

[0074] To connect the MOSFET device 3 and the sensor device 5 to each other, in the second embodiment, the thermal connection means 8 includes two pads 9, where:

[0075] At least one first pad 9a is located between the MOSFET device 3 and the first face 2a; and

[0076] At least one second pad 9b, thermally connected to the first pad 9a, is located between the second face 2b and the sensor device 5.

[0077] To allow for thermal connection between the first pad 9a and the second pad 9b, the thermal connection device 8 includes at least one thermal connection hole 11 (referred to as a "via hole" in technical terms), which is formed through the printed circuit board 2 and is adapted to thermally connect the first pad 9a and the second pad 9b to each other.

[0078] Specifically, the thermal connection hole 11 is of the metallized hole type.

[0079] More specifically, the thermal connection device 8 includes a plurality of thermal connection holes 11, visible in Figure 4 and Figure 5 as seen.

[0080] Specifically, the thermal connection holes 11 pass through the printed circuit board 2, the first pad 9a, and the second pad 9b.

[0081] These thermal connection holes 11 are lined with a thermally conductive material so that heat can be transferred from the first pad 9a to the second pad 9b.

[0082] Preferably, the thermal connection holes 11 are lined with copper, but the possibility of lining with different thermally conductive materials, such as other types of metallic materials, cannot be excluded.

[0083] It is important to note that this second embodiment achieves an additional and important technical result, namely, enabling the sensor device 5 to measure the temperature of the MOSFET device 3 significantly faster.

[0084] In fact, since the sensor device 5 is arranged on the opposite surfaces 2a, 2b of the printed circuit board 2 to the MOSFET device 3, the sensor device 5 is not affected in any way by any proximity or distance between the sensor device 5 and the MOSFET device 3 and can easily respond to the junction temperature (i.e., the temperature of the MOSFET device 3 and the temperature of the pads 9 during the operation of the device 1).

[0085] It should also be noted that in this second embodiment, the thermal connection element 10 is located between the MOSFET device 3 and the first pad 9a.

[0086] In this regard, to further improve the conduction efficiency of the thermal connection element 10, in Figure 6 the third embodiment of the device 1 shown, the thermal connection device 8 includes at least one thermal connection opening 12, which is formed through the first pad 9a, the printed circuit board 2, and the second pad 9b.

[0087] In fact, except for providing the thermal connection opening 12 and related facilitating measures, the third embodiment of the device 1 is the same as the second embodiment in all aspects.

[0088] More precisely, in this regard, the thermal connection opening 12 is formed with a sufficient size to allow the thermal connection element 10 to be at least partially inserted therein.

[0089] Therefore, in this third embodiment, the thermal connection element 10 is located between the MOSFET device 3 and the sensor device 5, further and smoothly improving the thermal coupling therebetween.

[0090] In practice, it has been determined that the described invention achieves the intended purpose.

[0091] In particular, emphasis is placed on the fact that the provision of one or more pads made of a thermally conductive material and placing them between the MOSFET device and the sensor device enables an absolutely precise and reproducible thermal coupling to be achieved between the MOSFET device and the sensor device for all manufactured products.

Claims

1. A power conversion electronic device (1) for an electric vehicle or a hybrid vehicle, which is installed in at least one electric vehicle or hybrid vehicle and can be connected to at least one battery of the vehicle, comprising: at least one printed circuit board (2); a plurality of power components configured to convert at least one input current / voltage into at least one predefined output current / voltage for delivery to the battery, the power components being mounted on the printed circuit board (2) and including at least one SMD or PTH top-cooled MOSFET device (3); at least one sensor device (5) operatively associated with the MOSFET device (3) and adapted to sense at least one temperature value from the MOSFET device (3); at least one layer (6) made of an electrically insulating and thermally conductive material, arranged in contact with each of the power components; at least one heat sink body (7) associated with the layer (6) and adapted to dissipate heat generated by the power components; characterized in that, the power conversion electronic device (1) includes a thermal connection device (8) between the MOSFET device (3) and the sensor device (5), the thermal connection device (8) including at least one pad (9) made of a thermally conductive material and placed between the MOSFET device (3) and the sensor device (5).

2. The device (1) according to claim 1, characterized in that, the thermal connection device (8) includes at least one thermal connection element (10) located between the MOSFET device (3) and the pad (9) and adapted to facilitate heat transfer from the MOSFET device (3) to the pad (9).

3. The device (1) according to claim 2, characterized in that, the thermal connection element (10) is of the type of thermal paste.

4. The device (1) according to one or more of the preceding claims, characterized in that, the printed circuit board (2) includes at least one first surface (2a) and at least one second surface (2b) opposite to each other, the MOSFET device (3) and the sensor device (5) are arranged on the first surface (2a), and the pad (9) is mounted between the MOSFET device (3) and the sensor device (5) on the first surface (2a).

5. The device (1) according to claim 4, characterized in that, the thermal connection device (8) includes a single said pad (9), the pad (9) being arranged in contact with the MOSFET device (3) and the sensor device (5) on the first surface (2a).

6. The device (1) according to one or more of claims 1 to 3, characterized in that: the MOSFET device (3) is arranged on the first surface (2a), and the sensor device (5) is arranged on the second surface (2b); and the thermal connection device (8) includes two said pads (9), wherein: at least one first pad (9a), located between the MOSFET device (3) and the first face (2a); and at least one second pad (9b), thermally connected to the first pad (9a), the at least one second pad (9b) being located between the second face (2b) and the sensor device (5).

7. The device (1) according to claim 6, characterized in that the thermal connection means (8) comprises at least one thermal connection hole (11) formed through the printed circuit board (2) and adapted to thermally connect the first pad (9a) and the second pad (9b) to each other.

8. The device (1) according to claim 6 or 7, characterized in that the thermal connection element (10) is located between the MOSFET device (3) and the first pad (9a).

9. The device (1) according to claim 6 or 7, characterized in that the thermal connection means (8) comprises at least one thermal connection opening (12) formed through the first pad (9a), the printed circuit board (2) and the second pad (9b), the thermal connection element (10) being at least partially mounted within the thermal connection opening (12).

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