Power conversion device

Abstract

The present invention provides a power conversion device comprising: a busbar, a power module housing holding the busbar, and power devices connected to the busbar by solder. The busbar includes a first busbar and a second busbar arranged in parallel and facing each other. The power module housing has a busbar exposure opening that exposes the side of the first busbar opposite to the facing surface of the second busbar.

Description

Technical Field

[0001] This invention relates to power conversion devices.

[0002] This application claims priority based on Japanese Patent Application No. 2019-172853 filed in Japan on September 24, 2019, the contents of which are incorporated herein by reference. Background Technology

[0003] In electric vehicles and other vehicles, a power conversion unit (PCU) is installed between the battery and the motor. This power conversion unit includes multiple power devices (power semiconductor chips) and a power module housing that houses these power devices. For example, as disclosed in Japanese Patent Application Publication No. 2014-187818, a busbar serving as a power path is enclosed within the power module housing. The busbar is connected to the power devices using solder.

[0004] The problem that the invention aims to solve

[0005] However, in the case of soldering such busbars and power devices, a reflow oven is typically used to melt the solder and connect the busbar to the terminals of the power devices. However, during the reflow soldering process, the entire power module housing containing the busbar is heated in the reflow oven. The busbar needs to be heated to a target temperature during the reflow soldering process. Therefore, the power module remains at a high temperature in the reflow oven until the busbar reaches the target temperature. To reduce the load on the power module housing during the reflow soldering process, it is desirable to shorten the busbar heating time. Summary of the Invention

[0006] The present invention was made in view of the above-mentioned problems, and its object is to shorten the heating time of the busbar in the reflow soldering process in a power conversion device.

[0007] Solution for solving the problem

[0008] The present invention adopts the following solution as a solution to the above problems.

[0009] The first solution adopts the following structure: a power conversion device comprising: a busbar; a power module housing holding the busbar; and power devices connected to the busbar by solder. The busbar comprises a first busbar and a second busbar arranged in parallel and facing each other. The power module housing has a busbar exposure opening that exposes the side of the first busbar opposite to the facing surface of the second busbar.

[0010] The second solution, in addition to the first solution, adopts the following structure: a plurality of exposed busbar openings are provided dispersedly along the extension direction of the first busbar.

[0011] The third solution, in addition to the second solution, adopts the following structure: the power module housing has a bridging portion, which is disposed between the exposed openings of the busbars and contains a bridging power path that crosses the first busbar.

[0012] The fourth scheme, in any of the first to third schemes above, adopts the following structure: the busbar has: a base formed in the shape of a long strip plate, and a connection portion protruding from the side edge of the base and connected to the power device by solder, wherein the power module housing is molded without exposing the side edge of the base.

[0013] The fifth scheme, in any of the first to fourth schemes mentioned above, adopts the following structure: when viewed from the arrangement direction of the first busbar and the second busbar, a plurality of the power devices are arranged across the first busbar in a direction orthogonal to the extension direction of the first busbar.

[0014] Invention Effects

[0015] According to the above-described embodiments of the present invention, the first busbar and the second busbar are arranged parallel to each other and facing each other, and a portion of the side of the first busbar opposite to the facing surface of the second busbar is exposed through a busbar exposure opening provided in the power module housing. Therefore, during the reflow soldering process, in the area exposed through the busbar exposure opening, heat from the reflow oven is not blocked by the power module and reaches the first busbar. As a result, the first busbar can be heated up in a short time. Furthermore, since the first busbar and the second busbar are arranged facing each other, the second busbar can also be heated up in a short time via the first busbar. Therefore, according to the above-described embodiments of the present invention, the heating time of the busbars in the reflow soldering process can be shortened in the power conversion device. Attached Figure Description

[0016] Figure 1 This is an exploded perspective view showing the schematic structure of a power conversion device according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic top view of the power module included in a power conversion device according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic top view of a power module, with the busbar represented by a solid line, included in a power conversion device according to an embodiment of the present invention.

[0019] Figure 4A yes Figure 2 AA sectional view.

[0020] Figure 4B yes Figure 2 BB cross-sectional view.

[0021] Explanation of reference numerals in the attached figures

[0022] 1 Power conversion device, 2 Intelligent power module, 3 Capacitor, 4 Main body housing, 10 Power module, 10a Power device, 10a1 Terminal, 10b Power module housing, 10b1 Receiving recess, 10b2 Central busbar holding part, 10b3 Busbar exposed opening, 10b4 Bridging part, 10b5 Connection terminal, 10c Busbar, 10d Water jacket, 10e Upper busbar (first busbar), 10f Lower busbar (second busbar), 10g Bridging busbar (bridging power path), 10h Insulation layer, 10i Base, 10j Connection part, 10k Solder, 11 Circuit board Detailed Implementation

[0023] Hereinafter, an embodiment of the power conversion device of the present invention will be described with reference to the accompanying drawings.

[0024] Figure 1 This is an exploded perspective view showing the schematic structure of the power conversion device 1 according to this embodiment. The power conversion device 1 of this embodiment is mounted in a vehicle such as an electric vehicle and is positioned between a motor (load) (not shown) and a battery. Figure 1 As shown, the power conversion device 1 of this embodiment includes a smart power module 2, a capacitor 3, and a main housing 4.

[0025] The intelligent power module 2 includes a power module 10, a circuit board 11, and a current sensor (not shown). The power module 10 includes: multiple power devices 10a (not shown) having power semiconductor elements (see reference). Figure 2 ), the power module housing 10b that holds these power devices 10a, and the busbar 10c connected to the power devices 10a (see reference). Figure 2 The circuit board 11 is stacked on the power module 10 and includes a drive circuit for driving the power device 10a. The current sensor (not shown) is a sensor that detects the current flowing in the bus 10c and is held in the power module housing 10b.

[0026] The capacitor 3 is connected to the smart power module 2 and is positioned on the opposite side of the circuit board 11, separated from the power module 10. The main housing 4 is a housing that houses the smart power module 2 and the capacitor 3, and includes an upper housing 4a, a central housing 4b, and a lower housing 4c. These upper housing 4a, central housing 4b, and lower housing 4c are connected in a manner that allows them to be separated in the stacking direction of the power module 10 and the circuit board 11. The upper housing 4a covers the smart power module 2 from the circuit board 11 side and is fastened to the central housing 4b. The central housing 4b houses a reactor and covers the periphery of the smart power module 2. The lower housing 4c is provided with a connector for connecting the smart power module 2 to a motor and is fastened to the central housing 4b.

[0027] The power conversion device 1 includes a step-up / step-down circuit and an inverter circuit, which consist of power devices, capacitors 3, and reactors. The power conversion device 1 converts the power supplied from the battery into three-phase alternating current and supplies it to the motor, or it feeds regenerated power from the motor back to the battery.

[0028] Figure 2 This is a top view of the power module 10 included in the power conversion device 1 of this embodiment. As described above, the power module 10 included in the intelligent power module 2 includes: a plurality of power devices 10a, a power module housing 10b holding the power devices 10a, and a busbar 10c connected to the power devices 10a.

[0029] Power device 10a is a chip-based switching device including a switching element driven by a drive circuit disposed on circuit board 11, such as an arm forming an inverter circuit. Figure 2 As shown, multiple power devices 10a are arranged such that they are sandwiched between the upper busbar 10e (described later) and the lower busbar 10f (described later) when viewed from above. These power devices 10a are arranged along the extension direction of the upper busbar 10e in their respective regions on one side (the region on one side of the upper busbar 10e in a direction orthogonal to its extension direction) and on the other side (the region on the other side of the upper busbar 10e in a direction orthogonal to its extension direction). In this embodiment, seven power devices 14 in total are arranged in both the region on one side and the region on the other side of the upper busbar 10e.

[0030] The power module housing 10b is formed of an insulating resin material and is generally rectangular with the direction in which the upper busbar 10e (and the lower busbar 10f) extends as its length direction. The power module housing 10b has the same number of receiving recesses 10b1 as the power device 10a for accommodating the power device 10a.

[0031] Furthermore, the power module housing 10b, in its approximately central portion in the width direction when viewed from above, has a central busbar holding portion 10b2 extending linearly in the length direction. This central busbar holding portion 10b2 encloses the upper busbar 10e and the lower busbar 10f. Moreover, the power module housing 10b of this embodiment has a plurality of busbar exposure openings 10b3 formed relative to the central busbar holding portion 10b2.

[0032] These busbar exposure openings 10b3 are openings that expose a portion of the surface of the upper busbar 10e. These busbar exposure openings 10b3 are arranged along the direction in which the upper busbar 10e extends (the extension direction). That is, in this embodiment, the power module housing 10b is provided with a plurality of busbar exposure openings 10b3 distributed along the extension direction of the upper busbar 10e.

[0033] Bridging portions 10b4 are provided between each other in the exposed busbar openings 10b3. That is, multiple bridging portions 10b4 are provided, and the bridging portions 10b4 are arranged along the upper busbar 10e in the same manner as the exposed busbar openings 10b3. Inside these bridging portions 10b4, a bridging busbar 10g (a bridging power path crossing the upper busbar 10e, described later) is enclosed. Thus, in this embodiment, the power module housing 10b includes bridging portions 10b4, which are disposed between each other in the exposed busbar openings 10b3, and enclose a bridging busbar 10g crossing the upper busbar 10e.

[0034] Furthermore, on the side of such a power module housing 10b, a plurality of connection terminals 10b5 are provided for electrical connection to capacitors 3, motor connectors, etc. Several of these connection terminals 10b5 are connected, for example, to a bridging bus 10g. Also, such a power module housing 10b is provided with a plurality of terminals for electrical connection of power devices 10a to circuit boards 11.

[0035] Bus 10c is a current-carrying path for allowing current to flow between a battery (not shown) and a motor (not shown), and is, for example, formed of copper. In this embodiment, the power module 10 includes an upper bus 10e (first bus), a lower bus 10f (second bus), and a bridging bus 10g as bus 10c.

[0036] Figure 3 This is a schematic top view of the power module 10, which uses solid lines to represent bus 10c. Additionally, Figure 4A yes Figure 2 AA section view, Figure 4B yes Figure 2 A BB sectional view. For example, as... Figure 4A as well as Figure 4BAs shown, the upper busbar 10e and the lower busbar 10f are arranged parallel to each other in a facing manner. The upper busbar 10e is positioned above the lower busbar 10f, and the lower busbar 10f is positioned below the upper busbar 10e. When viewed from above (from the direction in which the upper busbar 10e and lower busbar 10f are arranged), these upper busbars 10e and lower busbars 10f extend in a generally straight line along the length of the power device 10a. These upper busbars 10e and lower busbars 10f are connected to a battery (boost circuit), capacitor 3, etc. (not shown), via connection terminals 10b5 provided in the power module housing 10b.

[0037] An insulating layer 10h is provided between the upper busbar 10e and the lower busbar 10f. This insulating layer 10h is formed of resin, for example, and can be formed as a part of the power module housing 10b, or it can be a component separate from the power module housing 10b.

[0038] In addition, such as Figure 4A As shown, the upper busbar 10e and the lower busbar 10f each have a base 10i formed in the shape of an elongated plate, and a connecting portion 10j protruding from the side edge of the base 10i and pointing upwards. The connecting portion 10j is a portion that is connected to the terminal 10a1 of the power device 10a via solder 10k. The connecting portions 10j are discretely provided in the extending directions of the upper busbar 10e and the lower busbar 10f according to the arrangement position of the terminal 10a1 of the power device 10a.

[0039] In this embodiment, the side opposite to the opposing side of the facing side of the upper busbar 10e, which is formed as a plate, of the plate-shaped base 10i is exposed via the busbar exposure opening 10b3. On the other hand, the side edge of the plate-shaped base 10i is covered by the power module housing 10b, except for the area where the connecting portion 10j is provided. That is, the side edge of the base 10i is not exposed to the power module housing 10b during molding.

[0040] The bridging bus 10g is, for example, a bus 10c that connects a power device 10a located on one side of the upper bus 10e when viewed from above to a power device 10a located on the other side of the upper bus 10e when viewed from above. Additionally, the bridging bus 10g is a bus 10c that connects to power devices 10a, capacitors 3, motor connectors, etc. Figure 4B As shown, the bridging bus 10g is arranged to span the upper bus 10e and the lower bus 10f, and is enclosed by the bridging portion 10b4 of the power module housing 10b from above.

[0041] In manufacturing the power conversion device 1 of this embodiment, when assembling the power module 10, the busbar 10c and the power device 10a are joined using solder 10k during the reflow soldering process. Specifically, first, a power module housing 10b containing the busbar 10c is formed with the connection portion 10j exposed, and the power device 10a is placed in the receiving recess 10b1 of the power module housing 10b. Then, solder is applied in contact with the terminals 10a1 of the connection portion 10j and the power device 10a, and the power module housing 10b and the power device 10a are placed in a reflow oven for heating, thereby joining the busbar 10c and the power device 10a using solder 10k.

[0042] The power conversion device 1 of this embodiment, as described above, includes: a busbar 10c, a power module housing 10b holding the busbar 10c, and a power device 10a connected to the busbar 10c by solder. Furthermore, in the power conversion device 1 of this embodiment, the busbar 10c includes an upper busbar 10e and a lower busbar 10f arranged in parallel facing each other, and the power module housing 10b has a busbar exposure opening 10b3 that exposes the side of the upper busbar 10e opposite to the facing surface of the lower busbar 10f.

[0043] According to the power conversion device 1 of this embodiment, the upper bus 10e and the lower bus 10f are arranged parallel to each other and facing each other. A portion of the surface of the upper bus 10e opposite to the facing surface of the lower bus 10f is exposed through a busbar exposure opening 10b3 provided in the power module housing 10b. Therefore, during the reflow soldering process, in the area exposed through the busbar exposure opening 10b3, heat from the reflow oven is not blocked by the power module housing 10b and reaches the upper bus 10e. As a result, the upper bus 10e can be heated up in a short time. Furthermore, since the upper bus 10e and the lower bus 10f are arranged facing each other, the lower bus 10f can also be heated up in a short time via the upper bus 10e. Therefore, according to the power conversion device 1 of this embodiment, the heating time of the bus 10c in the reflow soldering process can be shortened.

[0044] Furthermore, in the power conversion device 1 of this embodiment, a plurality of busbar exposure openings 10b3 are provided dispersedly along the extension direction of the upper busbar 10e. According to this power conversion device 1 of this embodiment, compared to the case where the busbar exposure openings 10b3 are only partially provided, the surface of the upper busbar 10e is exposed at multiple locations along the extension direction of the upper busbar 10e. Therefore, the upper busbar 10e can be heated evenly in the extension direction. Furthermore, the lower busbar 10f can also be heated evenly in the extension direction.

[0045] Furthermore, in the power conversion device 1 of this embodiment, the power module housing 10b has a bridging portion 10b4, which is disposed between each other in the exposed busbar openings 10b3 and encloses the bridging busbar 10g that crosses the upper busbar 10e. According to this embodiment of the power conversion device 1, the bridging portion 10b4 enclosing the bridging busbar 10g is disposed between each other in the exposed busbar openings 10b3. Therefore, the strength of the power module housing 10b can be improved.

[0046] Furthermore, in the power conversion device 1 of this embodiment, the upper busbar 10e and the lower busbar 10f each have a base 10i formed in the shape of a long strip plate, and a connecting portion 10j protruding from the side edge of the base 10i and connected to the power device 10a by solder. The power module housing 10b is molded so that the side edge of the base 10i is not exposed. According to this power conversion device 1 of this embodiment, at least the base 10i of the upper busbar 10e and the lower busbar 10f are molded in the power module housing 10b. Therefore, the upper busbar 10e and the lower busbar 10f can be reliably held in place by the power module housing 10b, ensuring the insulation of the power module 10.

[0047] Furthermore, in the power conversion device 1 of this embodiment, viewed from the arrangement direction of the upper bus 10e and the lower bus 10f (the normal direction of the exposed area of ​​the upper bus 10e), a plurality of power devices 10a are arranged across the upper bus 10e in a direction orthogonal to the extending direction of the upper bus 10e. According to this power conversion device 1 of this embodiment, the plurality of power devices 10a can be arranged close to the upper bus 10e (and the lower bus 10f) which heats up in a short time, and the plurality of power devices 10a can be connected to the upper bus 10e (and the lower bus 10f) in a short time.

[0048] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it is understood that the present invention is not limited to the above embodiments. The shapes, combinations, etc. of the structural components shown in the above embodiments are examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0049] For example, in the above embodiment, a structure with multiple busbar exposure openings 10b3 has been described. However, the present invention is not limited thereto. For example, a structure with a single busbar exposure opening 10b3 may also be used.

[0050] Furthermore, in the above embodiment, a structure is adopted in which the bridging busbar 10g is enclosed within the bridging portion 10b4. However, the present invention is not limited to this. For example, a structure in which the bridging portion 10b4 does not enclose the bridging busbar 10g may also be adopted.

[0051] Industrial applicability

[0052] According to the present invention, the heating time of the busbar in the reflow soldering process can be shortened in the power conversion device.

Claims

1. A power conversion device, characterized in that, The power conversion device includes: busbar; The power module housing of the busbar is retained; and Power devices connected to the busbar using solder. The power module housing holds multiple power devices. The busbar includes a first busbar and a second busbar arranged in parallel and facing each other, with the first busbar positioned above the second busbar and the second busbar positioned below the first busbar. The power module housing has a busbar exposure opening that exposes the side of the first busbar opposite to the opposing surface of the second busbar. The power module housing is formed of an insulating resin material. An insulating layer formed from a portion of the power module housing is provided between the first busbar and the second busbar.

2. The power conversion device as described in claim 1, characterized in that, A plurality of exposed openings of the busbar are provided dispersedly along the extension direction of the first busbar.

3. The power conversion device as described in claim 2, characterized in that, The power module housing has a bridging portion disposed between the exposed openings of the busbars and includes a bridging power path that crosses the first busbar.

4. The power conversion device according to any one of claims 1 to 3, characterized in that, The busbar has: a base formed in the shape of a long strip plate, and a connection portion protruding from the side edge of the base and connected to the power device by solder. The power module housing is molded without exposing the side edges of the base.

5. The power conversion device as described in claim 1, characterized in that, Viewed from the arrangement direction of the first busbar and the second busbar, a plurality of power devices are arranged across the first busbar in a direction orthogonal to the extension direction of the first busbar.

6. The power conversion device as described in claim 2, characterized in that, Viewed from the arrangement direction of the first busbar and the second busbar, a plurality of power devices are arranged across the first busbar in a direction orthogonal to the extension direction of the first busbar.

7. The power conversion device as described in claim 3, characterized in that, Viewed from the arrangement direction of the first busbar and the second busbar, a plurality of power devices are arranged across the first busbar in a direction orthogonal to the extension direction of the first busbar.

8. The power conversion device as described in claim 4, characterized in that, Viewed from the arrangement direction of the first busbar and the second busbar, a plurality of power devices are arranged across the first busbar in a direction orthogonal to the extension direction of the first busbar.

Images