Inverter device and manufacturing method of inverter device

Abstract

An inverter device includes a housing, a switching element mounted to an inner surface of the housing, a capacitor arranged and mounted along a first direction on the inner surface and connected to the switching element, a first busbar extending along the first direction and connecting the switching element and the capacitor, a second busbar located on a side opposite to the inner surface across the first busbar, extending along the first direction, and connecting the switching element and the capacitor, a first solder mark extending on the first busbar in a second direction intersecting the first direction, and a plurality of second solder marks extending on the second busbar in a direction along the second direction and located on both sides of the first solder mark when viewed in a normal direction of the inner surface.

Description

Technical Field

[0001] This invention relates to an inverter device and a method for manufacturing the inverter device. Background Technology

[0002] Previously, inverter devices that drive high-output motors have been known to have large-capacity capacitors, for example, those with a capacitance of several hundred μF. These large-capacity capacitors are implemented, for example, as capacitor modules connecting multiple capacitor elements, and are connected to switching elements, i.e., power modules, within the inverter circuit via busbars.

[0003] When using busbars for connection, it is necessary to suppress the generation of loop inductance. However, when using screws or other fasteners to connect busbars, local misalignment occurs between the P-side and N-side busbars, thereby increasing the loop inductance. As a way to suppress loop inductance, busbar connections made by soldering are available.

[0004] For example, U.S. Patent Application Publication No. 2017 / 0133316 discloses a technique for connecting a capacitor and a semiconductor device by welding a busbar from the front side and the back side of the busbar, respectively.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: U.S. Patent Application Publication No. 2017 / 0133316 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, when connecting the switching element and capacitor using the technology disclosed in U.S. Patent Application Publication No. 2017 / 0133316, the switching element and capacitor are mounted in the housing after being connected via a busbar. Therefore, stress is applied to the welded areas of the busbar during installation, which may cause deformation or damage.

[0010] On the other hand, due to reasons such as installation space, the switching elements and capacitors are installed with the surface side or back side of the flat busbar facing the inner wall of the housing, making it difficult to solder them from the surface side and back side respectively after installation.

[0011] Therefore, the purpose of this disclosure is to enable busbar welding after the switching elements and capacitors have been mounted in the housing.

[0012] Solution for solving the problem

[0013] One embodiment of the inverter device disclosed herein includes: a housing; a switching element mounted on the inner surface of the housing; a capacitor mounted on the inner surface along a first direction and connected to the switching element; a first busbar extending along the first direction and connecting the switching element and the capacitor; a second busbar located on the opposite side of the inner surface, separated from the first busbar, extending along the first direction and connecting the switching element and the capacitor; a first weld mark extending on the first busbar in a second direction intersecting the first direction; and a plurality of second weld marks extending on the second busbar in a direction along the second direction and located on both sides separated from the first weld mark when viewed along the normal direction of the inner surface.

[0014] One aspect of the manufacturing method for the inverter device disclosed herein includes: an installation step in which a switching element and a capacitor connected to the switching element are arranged and installed along a first direction on the inner surface of a housing; a first welding step in which a first portion of a first busbar extending along the first direction and connecting the switching element and the capacitor, on the switching element side and a second portion on the capacitor side, are welded to form the first busbar; and a second welding step in which a first portion of a second busbar located on the opposite side of the inner surface and extending along the first direction and connecting the switching element and the capacitor, on the switching element side, a second portion on the capacitor side, and a third portion connecting the first portion and the second portion are welded at locations on both sides of the welding portion of the first busbar when viewed along the normal direction of the inner surface.

[0015] Invention Effects

[0016] According to this disclosure, it is possible to perform busbar welding after the switching elements and capacitors have been installed in the housing. Attached Figure Description

[0017] Figure 1 This is a three-dimensional diagram representing an inverter device.

[0018] Figure 2 This is a schematic side view showing the interior of the inverter unit's housing.

[0019] Figure 3 This is a diagram illustrating the installation process in the manufacturing method of an inverter device.

[0020] Figure 4 This diagram illustrates the first welding step in the manufacturing process of an inverter device.

[0021] Figure 5 This diagram illustrates the second welding step in the manufacturing process of an inverter device.

[0022] Figure 6 This is a diagram showing the inverter device of the first modified example.

[0023] Figure 7 This is a diagram showing the inverter device of the second modified example.

[0024] Figure 8 This is a partially enlarged view showing the second welding process in the second variation. Detailed Implementation

[0025] The following is a reference to the attached document. Figure 1 The present disclosure describes embodiments of the inverter device and the method of manufacturing the inverter device. However, to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art, necessary detailed descriptions are sometimes omitted. For example, detailed descriptions of already known matters and repeated descriptions of substantially the same structures are sometimes omitted. In addition, elements described in the figures above are sometimes appropriately referenced in the description of the figures later.

[0026] (Structure of inverter device 100)

[0027] Figure 1 This is a perspective view of the inverter device 100. Figure 2 This is a schematic side view showing the interior of the inverter unit 100's housing. Figure 1 and Figure 2 In the diagram, XYZ coordinates are shown for ease of illustrating direction.

[0028] The inverter device 100 is a device that converts direct current (DC) power supplied from sources such as batteries into alternating current (AC) power and supplies it to sources such as motors. The inverter device 100 can be installed in an electromechanical motor or can be a device that supplies power to a different source, such as a motor.

[0029] The inverter device 100 includes a housing 101, a power module 102, and a thin-film capacitor 103.

[0030] The housing 101 holds and protects the components disposed inside, and the internal space can be closed by a cover or left open without a cover. Figure 1 The image shows an example of an uncovered state.

[0031] The power module 102 is a modular assembly of multiple switching elements in the inverter circuit. The power module 102 is disposed within the housing 101 and mounted on the inner surface of the housing 101. Figure 1 and Figure 2 In the example, the bottom surface 108, located on the -Z side, is mounted on the inner surface. It should be noted that... Figure 2 Only the bottom surface 108 of the housing 101 is shown in the image.

[0032] The power module 102 can be directly mounted to the inner surface of the housing 101 by screws or the like, or indirectly mounted to the inner surface of the housing 101 by spacers or clamps.

[0033] The film capacitor 103 is a smoothing capacitor in the inverter circuit, and multiple capacitor elements are modularized to maximize capacitance. While electrolytic capacitors could be used as smoothing capacitors, the durable film capacitor 103 is employed here. The film capacitor 103 is also disposed within the housing 101, directly or indirectly mounted on the inner surface of the housing 101.

[0034] The power module 102 and the film capacitor 103 are arranged along the X direction within the housing 101, as an example, and are interconnected by busbars 104 and 105 to form an inverter circuit. Therefore, the busbars 104 and 105 extend along the X direction to connect the power module 102 and the film capacitor 103. As an example, each busbar 104 and 105 is a flat plate extending along the bottom surface 108 where the power module 102 and the film capacitor 103 are mounted. Therefore, compared to the case where they are not flat plates extending along the bottom surface 108, loop inductance is suppressed.

[0035] As an example, the busbar 104 and busbar 105 located on the -Z side is the N (Negative) busbar 104, and the busbar 105 located on the +Z side is the P (Positive) busbar 105. In other words, the busbar 104 and busbar 105 closer to the bottom surface 108 is the N busbar 104, and the busbar 105 located on the opposite side of the bottom surface 108, separated by the N busbar 104, is the P busbar 105.

[0036] N-busbar 104 is formed by welding a first portion 41 on the power module 102 side to a second portion 42 on the film capacitor 103 side. Therefore, the weld marks 106 in N-busbar 104 extend on N-busbar 104 in, for example, a Y direction that intersects the arrangement direction of the power module 102 and the film capacitor 103.

[0037] The P-bus 105 is formed by welding a first portion 51 on the power module 102 side, a second portion 52 on the film capacitor 103 side, and a third portion 53 connecting the first portion 51 and the second portion 52. That is, the third portion 53 of the P-bus 105 is located between the first portion 51 and the second portion 52. Furthermore, the weld mark 107 in the P-bus 105 extends along the direction of the weld mark 106 of the N-bus 104, and is located on both sides of the weld mark 106 of the N-bus 104 when viewed in the normal direction of the bottom surface 108. Therefore, as will be described later, the welding of the N-bus 104 and the P-bus 105 can be performed after the power module 102 and the film capacitor 103 are mounted on the inner surface of the housing 101.

[0038] If the busbars 104 and 105 are soldered before the power module 102 and the film capacitor 103 are mounted on the inner surface of the housing 101, deformation or damage may occur in the busbars 104 and 105 due to stress during installation. Therefore, it is required that the busbars 104 and 105 be soldered after the power module 102 and the film capacitor 103 are installed.

[0039] As an example, the weld mark 106 of the N busbar 104 is located at the center of the N busbar 104 in the X direction where the power module 102 and the film capacitor 103 are arranged. Therefore, welding is easier compared to the case where the weld mark 106 is biased towards one of the power module 102 and the film capacitor 103.

[0040] Furthermore, as an example, there is one solder mark 106 on the N bus 104, and as an example, there are two solder marks 107 on the P bus 105. Therefore, the loop inductance is suppressed by minimizing the solder marks 106 and 107.

[0041] (Manufacturing method of inverter device 100)

[0042] Next, the manufacturing method of the inverter device 100 will be described.

[0043] Figures 3-5 This is a diagram showing the various steps in the manufacturing method of the inverter device 100. Figure 3 The installation process is shown. Figure 4 The first welding process is shown. Figure 5 The second welding process is shown.

[0044] exist Figure 3In the installation process shown, the power module 102 and the film capacitor 103 are arranged along the X direction and installed on the bottom surface 108 of the inner surface of the housing 101, which is an example. At this time, the power module 102 and the film capacitor 103 are configured such that the front ends of the first part 41 and the second part 42 constituting the N busbar 104 are mated together or partially overlapped.

[0045] exist Figure 4 In the first welding process shown, the first portion 41 and the second portion 42 are welded to form the N busbar 104. Laser welding is used as an example in this first welding process. Specifically, laser L is irradiated onto the welding area of ​​the first portion 41 and the second portion 42 constituting the N busbar 104 to perform welding. The laser L irradiates the N busbar 104 from the side opposite to the bottom surface 108 and passes between the first portion 51 and the second portion 52 constituting the P busbar 105. Laser welding is easier to perform within the housing 101 compared to other types of welding.

[0046] exist Figure 5 In the second welding process shown, a third part 53 is disposed between the first part 51 and the second part 52 constituting the P busbar 105, and the first part 51, the second part 52, and the third part 53 are welded together. The welding positions in the second welding process are the portions on both sides of the welding positions in the first welding process when viewed in the normal direction of the bottom surface 108. As an example, laser welding, which is easy to weld within the housing 101, is also used in the second welding process. That is, laser L is irradiated onto the welding positions of the first part 51 and the third part 53 to perform welding, and laser L is also irradiated onto the welding positions of the third part 53 and the second part 52 to perform welding.

[0047] By performing the installation process, the first welding process, and the second welding process, the following results are obtained: Figure 1 and Figure 2 The inverter device 100 shown. Conversely, according to having Figure 1 and Figure 2 The inverter device 100 with the structure shown, as described above, is capable of performing a first welding process and a second welding process after the installation process. Therefore, deformation and damage to the busbars 104 and 105 are suppressed.

[0048] (Modified example)

[0049] Next, a modified example of the inverter device 100 described above will be explained.

[0050] Figure 6 This is a diagram showing the inverter device 110 of the first modified example.

[0051] The inverter device 110 of the first modification is similar to the one that includes insulating elements 111 and 112. Figure 1 and Figure 2 The inverter device 100 shown is different. Insulators 111 and 112 insulate busbars 104 and 105 from each other. Figure 6 In the example shown, insulating elements 111 and 112 cover both the front and back surfaces of busbars 104 and 105, but insulating elements 111 and 112 only need to cover the opposing surfaces of busbars 104 and 105.

[0052] The insulating element 111 of the N bus 104 covers a portion of its entire width in the X direction. Furthermore, the insulating element 112 of the P bus 105 covers the remaining portion of its entire width except for the portion without the insulating element 111 of the N bus 104. The insulating elements 111 of the N bus 104 and 112 of the P bus 105 are alternately arranged in the direction in which the power module 102 and the film capacitor 103 are arranged. It should be noted that the insulating elements 111 of the N bus 104 and 112 of the P bus 105 may also partially overlap.

[0053] That is, the insulating element 111 of the N busbar 104 covers a portion of the entire width of the surface of the N busbar 104 opposite to the P busbar 105, from the power module 102 to the film capacitor 103. Furthermore, the insulating element 112 of the P busbar 105 covers the remaining portion of the surface of the P busbar 105 opposite to the N busbar 104, which is complementary to the aforementioned portion of the N busbar 104. As a result, the busbars 104 and 105 are insulated from each other by a minimum amount of insulating elements 111 and 112.

[0054] The insulating element 111 of the N busbar 104 is disposed in the first portion 41 and the second portion 42 of the N busbar 104 at the location opposite to the weld line 107 of the P busbar 105, but does not reach the weld line 106 of the N busbar 104. Furthermore, the insulating element 112 of the P busbar 105 is disposed in the third portion 53 of the P busbar 105 at the location opposite to the weld line 106 of the N busbar 104, but does not reach the weld line 107 of the P busbar 105.

[0055] That is, the insulating element 111 of the N busbar 104 is disposed at a location that does not overlap with the weld line 106 of the N busbar 104, and the insulating element 112 of the P busbar 105 is disposed at a location that does not overlap with the weld line 107 of the P busbar 105. Therefore, the insulating elements 111 and 112 do not interfere with the welding in the first welding process and the welding in the second welding process, thus insulating the busbars 104 and 105 from each other.

[0056] Figure 7 This is a diagram showing the inverter device 120 of the second modified example.

[0057] The inverter device 120 of the second modification also has insulating members 111 and 121, similar to the first modification. In the second modification, the insulating member 121 of the P busbar 105 is thicker in the Z direction than in the first modification. Furthermore, the surface 122 of the insulating member 121 of the P busbar 105 opposite to the N busbar 104 reaches the N busbar 104. That is, the insulating member 121 of the P busbar 105 contacts the N busbar 104 at surface 122. From another perspective, the thickness of the insulating member 121 of the P busbar 105 on the N busbar 104 side is equivalent to the thickness of the distance between the P busbar 105 and the N busbar 104. As a result, as will be explained below, in the second welding process, the insulating member 121 of the P busbar 105 functions as a support member.

[0058] Figure 8 This is a partially enlarged view showing the second welding process in the second variation. Figure 8 The image shows a magnified view of the periphery of the welded area between the first part 51 and the third part 53 of the P busbar 105.

[0059] In the second variation, during the second welding process, welding is performed with the third portion 53 of the P busbar 105 supported on the N busbar 104 by the insulating member 121 of the P busbar 105. Therefore, there is no need to prepare other supporting members or the like for supporting the third portion 53 in the Z direction, and the execution of the second welding process is easy.

[0060] Furthermore, since the insulation 121 of the P busbar 105 is clamped by the insulation 111 of the N busbar 104, the third part 53 of the P busbar 105 is naturally positioned in the X direction, which also facilitates the execution of the second welding process.

[0061] The above-described embodiments should be considered exemplary and not limiting in all respects. The scope of the invention is set forth not by the above-described embodiments, but by the claims, and is intended to include the same meaning as the claims and all modifications within that scope.

[0062] It should be noted that this technology can be configured as described below. (1)

[0064] An inverter device comprising: case; A switching element is mounted on the inner surface of the housing; A capacitor is mounted on the inner surface along a first direction and connected to the switching element; A first busbar extends along the first direction and connects the switching element and the capacitor; The second busbar, located on the opposite side of the inner surface across the first busbar, extends along the first direction and connects the switching element and the capacitor; The first weld mark extends on the first busbar in a second direction intersecting the first direction; and Multiple second weld marks extend on the second busbar in a direction along the second direction and are located on both sides of the first weld mark when viewed in the normal direction of the inner surface. (2)

[0066] According to the inverter device described in (1), wherein, The first and second busbars are flat busbars that extend along the inner surface. (3)

[0068] According to the inverter device described in (1) or (2), wherein, The first weld mark exists at one point on the first busbar. There are two instances of the second weld mark on the second busbar. (4)

[0070] According to the inverter device described in (3), wherein, The first weld mark is located at the center of the first busbar in the first direction. (5)

[0072] The inverter device according to any one of (1) to (4) further comprises: A first insulating element covers a portion of the entire width of the surface of the first busbar opposite the second busbar, from the switching element to the capacitor; and The second insulating element covers the remaining portion of the second busbar that is complementary to the first busbar on its surface opposite to the first busbar. (6)

[0074] According to the inverter device described in (5), wherein, The first insulating component is disposed in a location that does not overlap with the first weld mark, and the second insulating component is disposed in a location that does not overlap with the second weld mark. (7)

[0076] According to the inverter device described in (5), wherein, The second insulating element is in contact with the surface of the first busbar. (8)

[0078] A method for manufacturing an inverter device, comprising: In the installation process, the switching element and the capacitor connected to the switching element are arranged and installed on the inner surface of the housing along a first direction; In the first welding process, a first portion on the side of the switch element and a second portion on the side of the capacitor in a first busbar that extends along the first direction and connects the switch element and the capacitor are welded together to form the first busbar. In the second welding process, the first portion on the switch element side, the second portion on the capacitor side, and the third portion connecting the first portion and the second portion of the second busbar, which is located on the opposite side of the inner surface and extends along the first direction and connects the switch element and the capacitor, are welded at the locations on both sides of the welding position of the first busbar when viewed along the normal direction of the inner surface. (9)

[0080] According to the manufacturing method of the inverter device described in (8), wherein, Laser welding is used in both the first and second welding processes. (10)

[0082] According to the manufacturing method of the inverter device described in (8) or (9), wherein, The second busbar has an insulating element that covers a portion of the surface of the third portion opposite to the first busbar. The second welding process is performed while the third portion of the second busbar is supported on the first busbar by the insulating element.

[0083] Explanation of reference numerals in the attached figures

[0084] 100, 110, 120: Inverter devices; 101: Shell; 102: Power module; 103: Film capacitor; 104: N busbar; 105: P busbar; 106, 107: Welding marks; 108: Bottom; 111, 112, 121: Insulating components.

Claims

1. An inverter device, the inverter device comprising: case; A switching element is mounted on the inner surface of the housing; A capacitor is mounted on the inner surface along a first direction and connected to the switching element; A first busbar extends along the first direction and connects the switching element and the capacitor; The second busbar, located on the opposite side of the inner surface across the first busbar, extends along the first direction and connects the switching element and the capacitor; The first weld mark extends on the first busbar in a second direction intersecting the first direction; and Multiple second weld marks extend on the second busbar in a direction along the second direction and are located on both sides of the first weld mark when viewed in the normal direction of the inner surface.

2. The inverter device according to claim 1, wherein, The first and second busbars are flat busbars that extend along the inner surface.

3. The inverter device according to claim 1, wherein, The first weld mark exists at one point on the first busbar. There are two instances of the second weld mark on the second busbar.

4. The inverter device according to claim 3, wherein, The first weld mark is located at the center of the first busbar in the first direction.

5. The inverter device according to claim 1, further comprising: A first insulating element covers a portion of the entire width of the surface of the first busbar opposite the second busbar, from the switching element to the capacitor; and The second insulating element covers the remaining portion of the second busbar surface that is complementary to the portion opposite to the first busbar.

6. The inverter device according to claim 5, wherein, The first insulating member is disposed at a location that does not overlap with the first weld mark, and the second insulating member is disposed at a location that does not overlap with the second weld mark.

7. The inverter device according to claim 5, wherein, The second insulating element is in contact with the surface of the first busbar.

8. A method for manufacturing an inverter device, the method comprising the following steps: In the installation process, the switching element and the capacitor connected to the switching element are arranged and installed on the inner surface of the housing along a first direction; In the first welding process, the first part of the first busbar extending along the first direction and connecting the switching element and the capacitor, on the side of the switching element and on the side of the capacitor, are welded together to form the first busbar. and In the second welding process, the first part of the second busbar located on the opposite side of the inner surface and extending along the first direction, connecting the switching element and the capacitor, the second part on the capacitor side, and the third part connecting the first part and the second part are welded at the locations on both sides of the welding position across the first busbar when viewed along the normal direction of the inner surface.

9. The method for manufacturing an inverter device according to claim 8, wherein, Laser welding is used in both the first and second welding processes.

10. The method for manufacturing an inverter device according to claim 8, wherein, The second busbar has an insulating element that covers a portion of the surface of the third portion opposite to the first busbar. The second welding process is performed while the third portion of the second busbar is supported on the first busbar by the insulating element.

Images