JP6693348B2 - Power converter - Google Patents

Description

  The technique disclosed in the present specification relates to a power conversion device. In particular, the present invention relates to a power converter having a stacked unit in which a plurality of coolers are arranged in parallel and a semiconductor module is sandwiched between adjacent coolers.

  For example, Patent Document 1 discloses a power conversion device including the above-described laminated unit. Each semiconductor module contains one to several switching elements. From the main body of the semiconductor module, a plurality of terminals (for example, a first terminal and a second terminal) internally connected to the switching element extend. The terminals of the plurality of semiconductor modules are arranged in the stacking direction of the semiconductor module and the cooler as an example. The first terminal group and the second terminal group are arranged in two rows. A capacitor unit containing a capacitor element is located next to the laminated unit. The first terminal of each semiconductor module and one electrode of the capacitor element are connected by a first bus bar, and the second terminal of each semiconductor module and the other electrode of the capacitor element are connected by a second bus bar. Each of the first bus bar and the second bus bar has a plate-shaped base portion, and a plurality of branch portions joined to the respective terminals extend from the base portion. Usually, the terminal and the branch are joined by welding. The plate-shaped base portion of the first bus bar and the plate-shaped base portion of the second bus bar are closely arranged to face each other. The inductance of the bus bar is reduced by arranging the two bases close to each other and facing each other.

JP, 2015-015787, A

  Each branch of the first bus bar and each first terminal are joined by welding, and each branch of the second bus bar and each second terminal are joined by welding. Since the first terminal group and the second terminal group are arranged in two rows, it is difficult to use a protective sheet or the like for separating the welded portion from the surroundings during welding. On the other hand, the base portions of the first bus bar and the second bus bar are arranged in close proximity to each other. Therefore, the two bus bars may be short-circuited by the welding powder scattered during welding. A structure that prevents a short circuit due to welding powder is desired.

  The power conversion device disclosed in this specification includes a laminated unit, a capacitor unit, a plate-shaped first bus bar, a plate-shaped second bus bar, an insulating plate, and a protective cover. In the laminated unit, a plurality of coolers are arranged side by side, and a semiconductor module containing a switching element is sandwiched between adjacent coolers. The capacitor unit is arranged next to the laminated unit. A capacitor element is housed in the capacitor unit, and a filler is filled around the capacitor element. The first bus bar is joined to the first terminal extending from each side surface of the plurality of semiconductor modules, and is also connected to one electrode of the capacitor element. The second bus bar is arranged opposite to the plate-shaped first bus bar. The second bus bar is joined to the second terminal extending from the side surface of each semiconductor module and is also connected to the other electrode of the capacitor element. The insulating plate is sandwiched between the first bus bar and the second bus bar and insulates the first bus bar from the second bus bar.

  The first terminals of the plurality of semiconductor modules are arranged in a row along the stacking direction of the cooler and the semiconductor module, and the second terminals are arranged in a row in parallel with the row of the first terminals. The plate-shaped first bus bar has a plurality of first holes through which the plurality of first terminals pass, and a first branch portion joined to the respective first terminals from the edge of each of the first holes. Is extended. The plate-shaped second bus bar is located on the side opposite to the laminated unit of the first bus bar, has a plurality of second holes through which the plurality of second terminals pass, and also has a plurality of second holes. A second branch portion that is joined to each second terminal extends from the edge of the. The second bus bar has a plurality of third holes through which the first terminals and the first branch portions pass. The insulating plate is provided with a plurality of tubular portions through which the respective first terminals and the first branch portions pass, and the respective tubular portions pass through the respective third holes of the second bus bar. The protective cover overlaps with the second bus bar on the opposite side of the insulating plate, is provided with a plurality of fourth holes through which the respective first terminals and the first branch portions pass, and insulates the edges of the respective fourth holes. The tips of the respective cylinders of the plates are in contact. The respective first terminals and the first branch portions are welded at the portions protruding from the tubular portion. A part of the protective cover is embedded in the filling material of the capacitor unit.

  According to the above-described power converter, first, the insulating plate arranged between the first bus bar and the second bus bar prevents the short circuit between the first bus bar and the second bus bar. In particular, the first branch portion and the first terminal of the first bus bar pass through the third hole of the second bus bar, but the first terminal and the first branch portion are surrounded by the tubular portion of the insulating plate, and the first terminal and The first branch portion is prevented from coming into contact with the second bus bar. A protective cover is overlaid on the second bus bar. The protective cover has a plurality of fourth holes. The respective first terminals and the first branch portions pass through the respective fourth holes. The tips of the cylindrical portions of the insulating plates are in contact with the edges of the respective fourth holes. And the 1st terminal and the 1st branch are welded in the part projected from the cylinder. Even if the welding powder falls into the tubular portion, a short circuit does not occur because the inside of the tubular portion is isolated from the second bus bar. Moreover, since the outer side of the tubular portion is covered with the protective cover, the welding powder that has fallen outside the tubular portion does not adhere to the second bus bar. In this way, a short circuit between the first bus bar and the second bus bar is prevented. A part of the protective cover is embedded in the filling material of the capacitor unit, so that it is firmly fixed.

  Details of the technology disclosed in the present specification and further improvements will be described in “Mode for Carrying Out the Invention” below.

It is a block diagram of a power system of an electric vehicle including a power converter of an example. It is a perspective view of an assembly of a lamination unit, a bus bar, and a capacitor unit. It is an exploded perspective view of a lamination unit, a bus bar, and a capacitor unit. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a cross-sectional view taken along the line VV of FIG. 2.

  A power converter according to an embodiment will be described with reference to the drawings. The power converter of the embodiment is a device that is mounted on an electric vehicle and that converts the power of a battery into the drive power of a traveling motor. FIG. 1 shows a block diagram of a power system of an electric vehicle 100 including the power conversion device 2. The electric vehicle 100 includes two traveling motors 83a and 83b. Therefore, the power conversion device 2 includes two sets of inverter circuits 13a and 13b. The outputs of the two motors 83a and 83b are combined / distributed by the gear box 85 and transmitted to the axle 86 (that is, the drive wheels).

  The power conversion device 2 is connected to the battery 81 via the system main relay 82. The power conversion device 2 includes a voltage converter circuit 12 that boosts the voltage of the battery 81, and two sets of inverter circuits 13a and 13b that convert the boosted DC power into AC.

  The voltage converter circuit 12 boosts the voltage applied to the terminal on the battery side and outputs it to the terminal on the inverter side, and lowers the voltage applied to the terminal on the inverter side and outputs it to the terminal on the battery side. It is a bidirectional DC-DC converter capable of performing both a step-down operation. For convenience of description, the terminal on the battery side (low voltage side) is referred to as an input terminal 18, and the terminal on the inverter side (high voltage side) is referred to as an output terminal 19 below. Further, the positive electrode and the negative electrode of the input end 18 are referred to as an input positive electrode end 18a and an input negative electrode end 18b, respectively. The positive electrode and the negative electrode of the output end 19 are referred to as an output positive electrode end 19a and an output negative electrode end 19b, respectively. The notations "input end 18" and "output end 19" are provided for the sake of convenience of description. As described above, the voltage converter circuit 12 is a bidirectional DC-DC converter. Power may flow from 19 to the input end 18.

  The voltage converter circuit 12 is composed of a series circuit of two switching elements 9a and 9b, a reactor 7, a filter capacitor 5, and a diode connected in antiparallel to each switching element. The reactor 7 has one end connected to the input positive electrode end 18a and the other end connected to the midpoint of the series circuit. The filter capacitor 5 is connected between the input positive electrode end 18a and the input negative electrode end 18b. The input negative electrode end 18b is directly connected to the output negative electrode end 19b. The switching element 9b is mainly involved in the step-up operation, and the switching element 9a is mainly involved in the step-down operation. The voltage converter circuit 12 shown in FIG. 1 is well known, and a detailed description thereof will be omitted. It should be noted that the circuit in the range of the broken line rectangle indicated by reference numeral 8a corresponds to the semiconductor module 8a described later. Reference numerals 25a and 25b indicate terminals extending from the semiconductor module 8a. Reference numeral 25a indicates a terminal (positive electrode terminal 25a) that is electrically connected to the high potential side of the series circuit of the switching elements 9a and 9b. Reference numeral 25b represents a terminal (negative electrode terminal 25b) that is electrically connected to the low potential side of the series circuit of the switching elements 9a and 9b. As described below, the notations of positive electrode terminal 25a and negative electrode terminal 25b are also used in other semiconductor modules.

  The inverter circuit 13a has a configuration in which three series circuits of two switching elements are connected in parallel. The switching elements 9c and 9d, the switching elements 9e and 9f, and the switching elements 9g and 9h form series circuits, respectively. A diode is connected in antiparallel to each switching element. The high-potential side terminal (positive terminal 25a) of the three sets of series circuits is connected to the output positive terminal 19a of the voltage converter circuit 12, and the low-potential side terminal (negative terminal 25b) of the three sets of series circuit is the voltage. It is connected to the negative output terminal 19b of the converter circuit 12. Three-phase alternating current (U-phase, V-phase, W-phase) is output from the midpoint of the three sets of series circuits. Each of the three sets of series circuits corresponds to the semiconductor modules 8b, 8c, 8d described later.

  Since the configuration of the inverter circuit 13b is the same as that of the inverter circuit 13a, the illustration of a specific circuit is omitted in FIG. Similarly to the inverter circuit 13a, the inverter circuit 13b also has a configuration in which three sets of series circuits of two switching elements are connected in parallel. The terminals on the high potential side of the three sets of series circuits are connected to the output positive terminal 19a of the voltage converter circuit 12, and the terminals on the low potential side of the three sets of series circuits are connected to the output negative terminal 19b of the voltage converter circuit 12. Has been done. The hardware corresponding to each series circuit is referred to as semiconductor modules 8e, 8f, 8g.

  The smoothing capacitor 6 is connected in parallel to the input terminals of the inverter circuits 13a and 13b. In other words, the smoothing capacitor 6 is connected in parallel to the output end 19 of the voltage converter circuit 12. The smoothing capacitor 6 removes the pulsation of the output current of the voltage converter circuit 12.

  The switching elements 9a-9h are transistors, typically IGBTs (Insulated Gate Bipolar Transistors), but may be other transistors, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The switching element here is used for power conversion and is sometimes called a power semiconductor element.

  In FIG. 1, each of broken lines 8a-8g corresponds to a semiconductor module. The power conversion device 2 includes seven sets of series circuits of two switching elements. As hardware, two switching elements forming a series circuit and a diode connected in antiparallel to each switching element are housed in one package. Hereinafter, when any one of the semiconductor modules 8a to 8g is shown without distinction, it is referred to as a semiconductor module 8.

  The high potential side terminal (positive electrode terminal 25a) of the seven semiconductor modules (7 sets of series circuits) is connected to the positive electrode of the smoothing capacitor 6, and the low potential side terminal (negative electrode terminal 25b) is the negative electrode of the smoothing capacitor 6. Connected to the electrodes. In FIG. 1, the conductive path in the broken line indicated by reference numeral 30 corresponds to a bus bar (positive electrode bus bar) that connects the positive electrode terminals 25a of the plurality of semiconductor modules 8 and the positive electrode of the smoothing capacitor 6 to each other. The conductive path in the broken line indicated by reference numeral 40 corresponds to a bus bar (negative electrode bus bar) that connects the plurality of negative electrode terminals 25b and the negative electrode of the smoothing capacitor 6 to each other. Next, the structures of the plurality of semiconductor modules 8, the positive electrode bus bar 30, and the negative electrode bus bar 40 will be described.

  FIG. 2 shows a perspective view of the hardware of the power conversion device 2. Note that, in FIG. 2, the housing of the power conversion device 2 and a part of the components are not shown. The plurality of semiconductor modules 8 (8a-8g) configure the laminated unit 20 together with the plurality of coolers 22. Since all of the semiconductor modules 8a to 8g have the same shape, in FIG. 2 and FIG. 3 described later, the leftmost semiconductor module is representatively denoted by the reference numeral 8, and the other semiconductor modules are not denoted by the reference numeral. Further, in FIG. 2 and FIG. 3 described later, the reference numeral 22 is attached only to the two leftmost coolers, and the reference numerals are omitted for the other coolers.

  FIG. 2 is a perspective view of the power conversion device 2, but only the assembly of the laminated unit 20, the positive electrode bus bar 30, the negative electrode bus bar 40, and the capacitor unit 60 is illustrated, and other parts are omitted from the drawing. The laminated unit 20 is a device in which a plurality of card type coolers 22 are arranged in parallel, and a card type semiconductor module 8 is sandwiched between adjacent coolers 22. The card-type semiconductor module 8 is stacked with its wide surface facing the cooler 22. Three terminals (a positive electrode terminal 25a, a negative electrode terminal 25b, and a midpoint terminal 25c) extend from one side surface 80a of each semiconductor module 8. In FIG. 2 and FIG. 3 described later, reference numerals 25a, 25b, and 25c are attached only to the terminals of the semiconductor module 8 located at the left end of the laminated unit 20, and the remaining semiconductor modules 8 are omitted from the reference numerals indicating the terminals.

  As described above, the positive electrode terminal 25a and the negative electrode terminal 25b are the high potential side terminal and the low potential side terminal of the series circuit housed in the semiconductor module 8. The midpoint terminal 25c is a terminal that is electrically connected to the midpoint of the series circuit. In other words, all of the three terminals 25a-25c are electrically connected to the switching element inside the semiconductor module 8. The three terminals 25a-25c extend in the Z-axis positive direction in the figure from one side surface 80a that intersects the wide surface of the semiconductor module 8. A plurality of control terminals extend in the negative Z-axis direction from the side surface opposite to the one side surface 80a. The control terminals are, for example, a gate terminal electrically connected to the gate electrode of the switching element built in the semiconductor module 8 and a signal terminal electrically connected to the temperature sensor and the current sensor built in the semiconductor module 8. .

  Hereinafter, for convenience of description, the stacking direction of the cooler 22 and the semiconductor module 8 in the stacking unit 20 will be simply referred to as the “stacking direction”. The X direction in the figure corresponds to the stacking direction.

  A coolant supply port 28 and a coolant discharge port 29 are provided in the cooler 22 at the right end in the figure. Adjacent coolers 22 are connected by two connecting pipes. One of the connecting pipes is located so as to overlap the refrigerant supply port 28 when viewed from the stacking direction. The other connecting pipe is located so as to overlap with the refrigerant discharge port 29 when viewed from the stacking direction. A refrigerant circulating device (not shown) is connected to the refrigerant supply port 28 and the refrigerant discharge port 29. The refrigerant supplied from the refrigerant supply port 28 is distributed to all the coolers 22 through one connecting pipe. The coolant absorbs heat from the adjacent semiconductor module 8 while passing through the cooler 22. The refrigerant that has absorbed the heat is discharged from the laminated unit 20 through the other connecting pipe and the refrigerant discharge port 29. Since each semiconductor module 8 is cooled from both sides thereof, the laminated unit 20 has high cooling performance.

  Each of the three terminals 25a-25c of each semiconductor module 8 has a flat plate shape. The positive electrode terminals 25a of the plurality of semiconductor modules 8 are arranged in a line in the stacking direction so as to face the flat surface of the positive electrode terminals 25a of the adjacent semiconductor modules 8. The negative electrode terminals 25b of the plurality of semiconductor modules 8 are also arranged in a line in the stacking direction so as to face the flat surfaces of the negative electrode terminals 25b of the adjacent semiconductor modules 8. The same applies to the midpoint terminals 25c of the plurality of semiconductor modules 8. The positive electrode terminals 25a, the negative electrode terminals 25b, and the midpoint terminals 25c of the plurality of semiconductor modules 8 are arranged in three rows.

  FIG. 3 shows an exploded perspective view of an assembly of the positive electrode bus bar 30, the negative electrode bus bar 40, the laminated unit 20, and the capacitor unit 60 (capacitor element 61). Two capacitor elements 61 are accommodated in the capacitor unit 60 shown in FIG. In FIG. 3, the case of the capacitor unit 60 is omitted and the internal capacitor element 61 is drawn. As will be described later in detail, the periphery of the capacitor element 61 in the case of the capacitor unit 60 is filled with a filler. The capacitor element 61 corresponds to the smoothing capacitor 6 in FIG.

  The positive electrode terminals 25a of the semiconductor modules 8 and the positive electrode 61a of the capacitor element 61 are connected by the positive electrode bus bar 30, and the negative electrode terminals 25b and the negative electrode 61b of the capacitor element 61 are connected by the negative electrode bus bar 40.

  The positive electrode bus bar 30 includes a plate-shaped electrode portion 39, a plate-shaped base portion 31, and a plurality of branch portions 33. The electrode portion 39 is connected to the positive electrode 61a of the capacitor element 61. A plurality of first holes 32 are provided in the base portion 31 of the positive electrode bus bar 30, and branch portions 33 extend from the edges of each first hole 32 in the Z direction. The positive electrode terminal 25a of each semiconductor module 8 passes through each first hole 32, and the positive electrode terminal 25a and the branch portion 33 are joined.

  The negative electrode bus bar 40 includes a plate-shaped electrode portion 49, a plate-shaped base portion 41, and a plurality of branch portions 43. The electrode portion 49 is connected to the negative electrode 61b of the capacitor element 61. The base portion 41 of the negative electrode bus bar 40 is provided with a plurality of second holes 42, and a branch portion 43 extends in the Z direction from the edge of each second hole 42. The negative electrode terminal 25b of each semiconductor module 8 passes through each second hole 42, and the negative electrode terminal 25b and the branch portion 43 are joined.

  The negative electrode bus bar 40 is located on the opposite side of the positive electrode bus bar 30 from the laminated unit 20. The negative electrode bus bar 40 is provided with a plurality of third holes 45, and the positive electrode terminal 25 a of the semiconductor module 8 passes through each of the third holes 45. The plate-shaped base portion 31 of the positive electrode bus bar 30 and the plate-shaped base portion 41 of the negative electrode bus bar 40 closely face each other.

  The insulating plate 50 is sandwiched between the positive electrode bus bar 30 and the negative electrode bus bar 40. The insulating plate 50 insulates between the positive electrode bus bar 30 and the negative electrode bus bar 40. The insulating plate 50 is provided with a plurality of tubular portions 53 and a plurality of fifth holes 54. Ribs 51 extending in the Y direction are provided on both sides of the insulating plate 50 in the stacking direction (X direction), and a protrusion 52 extends from each rib 51. The base 41 of the negative electrode bus bar 40 is accommodated between the pair of ribs 51.

  A protective cover 70 is arranged so as to overlap the negative electrode bus bar 40 on the opposite side of the insulating plate 50. The protective cover 70 is provided with a plurality of fourth holes 73, and the positive electrode terminal 25 a and the branch portion 33 of the positive electrode bus bar 30 pass through each of the fourth holes 73. The protective cover 70 has an insulating portion 72 made of an insulating material and a metal portion 71 made of copper. The metal portion 71 is provided with a fourth hole 73. Through holes 74 are provided in the protective cover 70 at positions corresponding to the protrusions 52 of the insulating plate 50. When the insulating plate 50, the negative electrode bus bar 40, and the protective cover 70 are overlapped with each other, the protrusion 52 of the insulating plate 50 fits into the through hole 74 of the protective cover 70, and the insulating plate 50 and the protective cover 70 are firmly connected. In FIG. 3, a portion indicated by reference numeral 72 a indicates a portion of the protective cover 70 that is embedded in the capacitor unit 60. This point will be described later.

  The relationship among the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70 will be described with reference to FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 2, and is a cross section that crosses the positive electrode terminal 25a. Note that FIG. 4 shows only a partial cross section of the assembly of the laminated unit 20, the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70.

  The positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70 overlap. As described above, the insulating plate 50 is sandwiched between the positive electrode bus bar 30 and the negative electrode bus bar 40, and insulates the both. Of the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70, the positive electrode bus bar 30 is located closest to the semiconductor module 8. The insulating plate 50 overlaps with the positive electrode bus bar 30, the negative electrode bus bar 40 overlaps with the insulating plate 50, and the protective cover 70 overlaps with it. The branch portion 33 of the positive electrode bus bar 30 is welded to the semiconductor module side of the base portion 31 of the positive electrode bus bar 30. The branch 33 extends from the edge of the first hole 32 of the base 31.

  The first hole 32 provided in the positive electrode bus bar 30, the cylindrical portion 53 provided in the insulating plate 50, the third hole 45 provided in the negative electrode bus bar 40, and the fourth hole 73 provided in the protective cover 70 are The positive electrode bus bar 30 and the negative electrode bus bar 40 overlap with each other when viewed in the stacking direction (Z direction in the drawing). The positive electrode terminal 25a of the semiconductor module 8 and the branch portion 33 of the positive electrode bus bar 30 pass through these holes. The positive electrode terminal 25a and the branch portion 33 of the positive electrode bus bar 30 pass through the inside of the tubular portion 53 of the insulating plate 50, and the tubular portion 53 itself passes through the third hole 45 of the negative electrode bus bar 40. The tip of the tubular portion 53 is in contact with the edge of the fourth hole 73 of the protective cover 70.

  With the above structure, the negative electrode bus bar 40 is separated from the branch portion 33 of the positive electrode bus bar 30 and the positive electrode terminal 25a in the vicinity of the positive electrode terminal 25a. First, the tubular portion 53 of the insulating plate 50 passes through the third hole 45 of the negative electrode bus bar 40, and the positive electrode terminal 25a and the branch portion 33 pass inside the tubular portion 53, so that the periphery of the third hole 45 is surrounded by the positive electrode terminal 25a. Is separated from the branch portion 33. Further, the tip of the tubular portion 53 contacts the edge of the fourth hole 73 of the protective cover 70, so that the metal portion 71 of the protective cover 70 covers the space Sp facing the surface of the base portion 41 of the negative electrode bus bar 40, and the base portion 41. Is separated from the positive electrode terminal 25a and the branch portion 33. The positive electrode terminal 25a and the branch portion 33 of the positive electrode bus bar 30 are welded to the tubular portion 53 and a portion protruding from the fourth hole 73. The arrow A in FIG. 4 schematically represents the laser light for welding. That is, the portion indicated by the arrow A is the welding portion of the positive electrode terminal 25a and the branch portion 33. During welding, welding powder may be scattered from the positive electrode terminal 25a or the branch portion 33. In FIG. 4, the dotted line indicated by the symbol Q schematically represents the welding powder. As described above, since the negative electrode bus bar 40 is separated from the positive electrode terminal 25a and the branch portion 33 around the positive electrode terminal 25a, welding powder does not adhere to the negative electrode bus bar 40. Therefore, the negative electrode bus bar 40 and the positive electrode bus bar 30 are prevented from being short-circuited via the welding powder. The fourth hole 73 of the protective cover 70 is provided in the metal portion 71, and the welding powder adheres to the metal portion 71. Since the welding powder adheres to the metal part 71, it is prevented from being scattered to another.

  FIG. 5 shows a cross section taken along line VV of FIG. FIG. 5 shows a cross section that crosses the tubular portion 53. Also in FIG. 5, the cylindrical portion 53 of the insulating plate 50 separates the edge of the third hole 45 of the negative electrode bus bar 40 from the positive electrode terminal 25a and the branch portion 33, and a protective cover is provided around the positive electrode terminal 25a. It is understood that 70 covers the negative electrode bus bar 40.

  The internal structure of the capacitor unit 60 will be described with reference to FIG. The capacitor element 61 is housed in the case 68 of the capacitor unit 60. The case 68 is made of insulating resin. Inside the case 68, a filling material 69 is filled around the capacitor element 61. The filler 69 is, for example, a potting material containing silicone. Inside the case 68, the electrode portion 39 of the positive electrode bus bar 30 is connected to the positive electrode electrode 61 a of the capacitor element 61, and the electrode portion 49 of the negative electrode bus bar 40 is connected to the negative electrode electrode 61 b of the capacitor element 61.

  Further, a part 72 a of the protective cover 70 has entered the inside of the capacitor unit 60 and is embedded in the filling material 69. Since the part 72a of the protective cover 70 is embedded in the filling material 69, the protective cover 70 is firmly fixed to the capacitor unit 60.

  The power conversion device 2 includes the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70, so that a short circuit between the positive electrode bus bar 30 and the negative electrode bus bar 40 is prevented. In particular, a short circuit due to welding powder when welding the branch portion 33 of the positive electrode bus bar 30 and the positive electrode terminal 25a of the semiconductor module 8 is prevented.

  Points to be noted regarding the technique described in the embodiment will be described. The positive electrode bus bar 30 of the embodiment corresponds to an example of the first bus bar in the claims, and the negative electrode bus bar 40 corresponds to an example of the second bus bar of the embodiment. The positive electrode terminal 25a of the embodiment corresponds to an example of the first terminal in the claims, and the negative electrode terminal 25b of the embodiment corresponds to an example of the second terminal in the claims. The branch portion 33 of the positive electrode bus bar 30 of the embodiment corresponds to an example of the “first branch portion” in the claims, and the branch portion 43 of the negative electrode bus bar 40 corresponds to an example of the “second branch portion” in the claims. The “positive electrode” and the “negative electrode” in the examples may be reversed.

  Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in the present specification or the drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technique illustrated in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes has technical utility.

2: Power converter 5: Filter capacitor 6: Smoothing capacitor 7: Reactor 8, 8a-8g: Semiconductor module 9a-9h: Switching element 12: Voltage converter circuit 13a, 13b: Inverter circuit 20: Laminated unit 22: Cooler 25a : Positive electrode terminal 25b: Negative electrode terminal 25c: Midpoint terminal 30: Positive electrode bus bar 31, 41: Base portion 32: First hole 33, 43: Branch portion 39, 49: Electrode portion 40: Negative electrode bus bar 42: Second hole 45: Second 3 holes 50: insulating plate 51: rib 52: protrusion 53: cylindrical portion 54: fifth hole 60: capacitor unit 61: capacitor element 61a: positive electrode 61b: negative electrode 68: case 69: filler 70: protective cover 71: Metal part 72: Insulating part 81: Battery 82: System main relays 83a and 83b: Motor 85: Gear box 100: Electricity Dosha

Claims (1)

A plurality of coolers are arranged side by side, between the adjacent coolers, a stacked unit in which a semiconductor module containing a switching element is sandwiched,
A capacitor unit which is arranged next to the laminated unit, contains a capacitor element, and is filled with a filler around the capacitor element;
A plate-shaped first bus bar that is joined to the first terminals extending from the respective side surfaces of the plurality of semiconductor modules and that is connected to one electrode of the capacitor element;
A plate-shaped member that is arranged to face the plate-shaped first bus bar, is joined to the second terminal extending from the side surface of each semiconductor module, and is connected to the other electrode of the capacitor element. Second bus bar of
An insulating plate sandwiched between the first bus bar and the second bus bar;
With a protective cover,
Is equipped with
The first terminals of the plurality of semiconductor modules are arranged in a row along the stacking direction of the cooler and the semiconductor module, and the plurality of second terminals are arranged in a row in parallel with the row of the first terminals. Are lined up,
The first bus bar has a plurality of first holes through which each of the plurality of first terminals passes, and a first branch portion that is joined to each of the first terminals from an edge of each of the first holes. Is extended,
The second bus bar is located on the opposite side of the first bus bar from the laminated unit, has a plurality of second holes through which the plurality of second terminals pass, and has a plurality of second holes. A second branch portion that is joined to each of the second terminals extends from the edge of the hole, and includes a plurality of third holes through which each of the first terminals and each of the first branch portions pass.
The insulating plate includes a plurality of tubular portions through which the respective first terminals and the first branch portions pass, and the respective tubular portions pass through the respective third holes of the second bus bars. Cage,
The protective cover overlaps with the second bus bar on the side opposite to the insulating plate, and is provided with a plurality of fourth holes through which the first terminals and the first branch portions pass, respectively. The tip of each cylinder of the insulating plate is in contact with the edge of the hole,
Each of the first terminal and the first branch portion is welded at a location protruding from the tubular portion,
A power converter in which a part of the protective cover is embedded in the filling material of the capacitor unit.

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