Capacitor

Abstract

To provide a capacitor having a plurality of output terminals in which amounts of heat generated by each of a plurality of capacitor elements connected in parallel can be equalized.SOLUTION: A capacitor 80 includes a plurality of capacitor elements 84, and a pair of bus bars 86a, 86b electrically connecting the plurality of capacitor elements 84 in parallel. Each of the bus bars 86a, 86b includes: an input terminal 86e that can input power from a battery to the plurality of capacitor elements 84; a first output terminal 86c that outputs power from the plurality of capacitor elements 84 to a first electronic component; a second output terminal 86d that outputs power from the plurality of capacitor elements 84 to a second electronic component and is at a distance from the input terminal 86e longer than a distance between the first output terminal 86c and the input terminal 86e; and a slit 86g that is formed between the first output terminal 86c and the second output terminal 86d and bypasses a current path of a current flowing from the input terminal 86e to the second output terminal 86d.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to capacitors. [Background technology]

[0002] In recent years, automobiles equipped with motors as a driving source (such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs)) have become widespread. These automobiles use vehicle drive systems that incorporate a driving motor, a power supply module, an inverter, and the like. In the vehicle drive system, various electronic components, including a capacitor, are fixed to a base.

[0003] Patent Document 1 discloses a power unit for a power converter. The power unit for a power converter is configured by mounting a capacitor consisting of a plurality of capacitor elements (unit capacitors in Patent Document 1) connected in parallel, a power module including a switching chip, a cooler, and a pattern conductor for electrical connection on a large-current wiring board. The pattern conductor of the power unit for a power converter has slits formed in it to equalize the wiring lengths of the plurality of capacitor elements. This equalizes the wiring inductance of each capacitor element, balancing circuit operation and improving reliability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-352767 Summary of the Invention [Problem to be solved by the invention]

[0005] When a capacitor element has one input terminal and two output terminals, if the output terminals are located in different locations, current may flow only through some of the parallel-connected capacitor elements, or the magnitude of the current flowing through each capacitor element may differ depending on the location of the output terminals. In this case, the amount of heat generated by capacitor elements through which current flows or flows in large amounts increases, while the amount of heat generated by capacitor elements through which no current flows or flows only partially decreases. Because the lifespan of a capacitor element is affected by the amount of heat generated, this configuration may result in variations in the lifespan of multiple capacitor elements that make up a single capacitor, leaving room for improvement.

[0006] Therefore, there is a demand for a capacitor that has a plurality of output terminals and that can equalize the amount of heat generated by a plurality of capacitor elements connected in parallel. [Means for solving the problem]

[0007] One embodiment of a capacitor according to the present disclosure includes a plurality of capacitor elements and a pair of bus bars that electrically connect the plurality of capacitor elements in parallel, each of the pair of bus bars including an input terminal that can input power from a battery to the plurality of capacitor elements, a first output terminal that outputs power from the plurality of capacitor elements to a first electronic component, a second output terminal that outputs power from the plurality of capacitor elements to a second electronic component and is farther from the input terminal than the first output terminal, and a slit that is formed between the first output terminal and the second output terminal and that diverts a current path that flows from the input terminal to the second output terminal.

[0008] The current supplied from the input terminal to the capacitor flows through the bus bar via a current path with low conductor resistance to the output terminal and is output from the output terminal. In other words, the current flows concentratedly through the capacitor element connected to the bus bar at a location where the current path to the output terminal has low conductor resistance, and the current does not flow easily through the capacitor element connected to the bus bar at a location where the current path to the output terminal has high conductor resistance. In this configuration, a slit is provided between the first output terminal and the second output terminal, so that the capacitor element connected to the bus bar at a location where the current path to the first output terminal has low conductor resistance and the capacitor element connected to the bus bar at a location where the current path to the second output terminal has low conductor resistance are different capacitor elements.

[0009] Specifically, for multiple capacitor elements arranged near the first output terminal, the current path from the multiple capacitor elements to the second output terminal is long because it needs to take a detour using slits. Therefore, the conductor resistance of the bus bar from the multiple capacitor elements arranged near the first output terminal to the second output terminal is large, so the current flowing through the multiple capacitor elements arranged near the first output terminal is output almost entirely from the first output terminal. Conversely, for multiple capacitor elements arranged far from the first output terminal, the current path from the multiple capacitor elements to the second output terminal is shorter than the current path to the first output terminal because it does not need to take a detour using slits. Therefore, the conductor resistance of the bus bar from the multiple capacitor elements arranged far from the first output terminal to the second output terminal is small, so the current flowing through the multiple capacitor elements arranged far from the first output terminal is output almost entirely from the second output terminal.

[0010] In this way, the current flowing through the multiple capacitor elements arranged at different locations is output from different output terminals, allowing the current to flow through all of the multiple capacitor elements. As a result, by appropriately setting the slit length of the slits, the amount of heat generated by each of the multiple capacitor elements through which the current output from the first output terminal flows can be made equal to the amount of heat generated by each of the multiple capacitor elements through which the current output from the second output terminal flows. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a circuit diagram of a cooling circuit including a vehicle drive device equipped with a capacitor according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the vehicle drive device and the housing. [Figure 3] FIG. 2 is a perspective view of a power circuit assembly. [Figure 4] FIG. 2 is a circuit diagram of a power circuit assembly. [Figure 5] FIG. 2 is an exploded perspective view of the smoothing capacitor according to the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view illustrating the configuration of a bus bar of a smoothing capacitor. [Figure 7] FIG. 4 is a cross-sectional view illustrating a configuration of a bus bar of a smoothing capacitor according to a modified example of the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view illustrating the configuration of a bus bar of a smoothing capacitor according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view illustrating the configuration of a bus bar of a smoothing capacitor according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a capacitor according to the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are merely examples for explaining the capacitor, and the capacitor is not limited to these embodiments. Therefore, the capacitor can be embodied in various forms without departing from the spirit of the present disclosure.

[0013] [First embodiment] [Configuration of cooling circuit] As shown in FIG. 1, a vehicle drive device A equipped with a smoothing capacitor 80 (an example of a capacitor, see FIG. 2) according to the first embodiment is mounted on a cooling circuit consisting of a coolant flow path L1 for circulating a coolant as a cooling fluid, a refrigerant flow path L2 for circulating a refrigerant, and a lubricant flow path L3 for circulating a lubricant.

[0014] The coolant flow path L1 is driven by a coolant pump 33 to circulate the coolant through the radiator 34, the cooling plate 11 of the power circuit assembly PE, the oil cooler 32, and the water-cooled condenser 31 in that order. The coolant is cooling water such as long-life coolant (LLC), or insulating oil such as paraffin-based oil.

[0015] The refrigerant flow path L2 is configured to supply an externally cooled refrigerant to the water-cooled condenser 31. In this refrigerant flow path L2, a hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO), or the like is used as the refrigerant.

[0016] The lubricating oil passage L3 supplies low-temperature lubricating oil to the inside of the traveling motor M and the gear mechanism Ge when the hydraulic pump 35 is driven.

[0017] In this cooling circuit, the coolant cooled by the radiator 34 flows through a flow path formed inside the cooling plate 11 of the power circuit assembly PE. As a result, the coolant absorbs heat generated in the power circuit assembly PE and cools the power circuit assembly PE. As a result, the temperature of the coolant rises.

[0018] The oil cooler 32 is disposed downstream of the power circuit assembly PE in the coolant flow path L1, and exchanges heat between the coolant circulating through the coolant flow path L1 and the lubricant circulating through the lubricant flow path L3. This further increases the temperature of the coolant and decreases the temperature of the lubricant. The cooled lubricant flows through the lubricant flow path L3 and is supplied to the drive motor M and the gear mechanism Ge. This prevents the drive motor M and the gear mechanism Ge from increasing in temperature and lubricates the drive motor M and the gear mechanism Ge. The coolant, whose temperature has increased in the oil cooler 32, removes heat from the refrigerant in the water-cooled condenser 31, then dissipates heat in the radiator 34, where it is cooled and supplied to the power module B again.

[0019] [Configuration of vehicle drive device] 2 shows a vehicle drive device A that transmits the driving force of a traction motor M to wheels (not shown). This vehicle drive device A accommodates the traction motor M, a drive shaft DS connected to transmit the driving force of the traction motor M to the wheels, a gear mechanism Ge that reduces the driving force of the traction motor M and transmits it to the drive wheels, and a power circuit assembly PE including a power module B and an inverter C, all housed in a housing AH. Hereinafter, a vehicle equipped with a traction motor M as a driving source will also be referred to as an electric vehicle. Examples of electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs).

[0020] The housing AH includes a first housing chamber E1 that houses the travel motor M, and a second housing chamber E2 that houses a power supply module B and an inverter C that control the power supplied to the travel motor M. The direction perpendicular to the vertical direction Z and along the rotation axis A1 of the rotor (not shown) of the travel motor M is defined as the axial direction L, the direction orthogonal to the vertical direction Z and the axial direction L is defined as the axial-orthogonal direction Y, and one side of the axial-orthogonal direction Y is defined as the axial-orthogonal first side Y1.

[0021] The housing AH has a first cover 101 that closes the outside of the drive motor M in the first accommodation chamber E1, and a second cover 102 that closes the outside of the gear mechanism Ge in the first accommodation chamber E1. In addition, an opening at the top of the housing AH is closed by an upper cover 103. This gives the housing AH a sealed structure.

[0022] The gear mechanism Ge includes a differential gear mechanism 110 arranged on the same axis as the rotation axis A1 of the drive shaft DS of the driving motor M, and a counter gear mechanism 111 arranged on an offset axis B1 offset from the rotation axis A1.

[0023] When mounted on an electric vehicle, the second storage chamber E2 has an upper region E3 which is above the driving motor M in the vertical direction Z and overlaps with the driving motor M when viewed in a direction along the Z direction (hereinafter also referred to as a planar view), and a lateral region E4 which is adjacent to the upper region E3 and is on the first side Y1 in the direction perpendicular to the axis of the driving motor M and does not overlap with the driving motor M when viewed in a planar view.

[0024] In the vehicle drive device A of this embodiment, at least a portion of the inverter C is disposed in the upper area E3, and the power supply module B is disposed in an area extending below the inverter C in the side area E4.

[0025] That is, in this embodiment, when viewed in the direction along the axial direction L (hereinafter also referred to as a side view), if the inverter C is in a horizontal position, the power supply module B extends in the vertical direction Z, thereby forming an L-shape between the inverter C and the power supply module B. In other words, the inverter C is arranged in a horizontal position above the traction motor M in an area extending in the axially orthogonal direction Y in the upper area E3 of the second housing chamber E2, and the power supply module B is arranged in a vertical position in a side area E4 adjacent to the upper area E3 and extending in the vertical direction. Note that instead of the arrangement of this embodiment, the power supply module B may be arranged in the upper area E3 and the inverter C in the side area E4.

[0026] In this embodiment, the side opposite to the axially orthogonal direction first side Y1 in the direction along the axially orthogonal direction Y is referred to as the axially orthogonal direction second side Y2, and either the axially orthogonal direction first side Y1 or the axially orthogonal direction second side Y2 may be the front side of the body of the electric vehicle.

[0027] [Configuration of power circuit assembly] 4 shows a circuit diagram of the power circuit assembly PE. The power circuit assembly PE includes a filter unit 40 and an OBC unit 50 that constitute a power supply module B, an auxiliary inverter unit 60 (an example of a second electronic component) and a main inverter unit 65 that constitute an inverter C, and a control unit D.

[0028] [Filter unit] The filter unit 40 includes an input connector 40a, an output connector 40b, an AC filter 22, a relay module 42, a coil module 21, a current detection module 44, and an input / output control unit 45. The input / output control unit 45 outputs a control signal to the relay module 42 and acquires a detection signal from the current detection module 44.

[0029] [OBC Unit] The OBC unit 50 includes a transformer T, a low-voltage connector 50a, a conversion circuit 51, a primary coil control circuit 52, a bulk capacitor 16, a secondary coil control circuit 54, a tertiary coil control circuit 55, a conversion circuit control unit 56, a transformer control unit 57, and a low-voltage control unit 58. The primary coil control circuit 52 controls the primary coil T1 of the transformer T. The bulk capacitor 16 is disposed in a power system that transmits power from the conversion circuit 51 to the primary coil control circuit 52. The secondary coil control circuit 54 controls the secondary coil T2 of the transformer T. The tertiary coil control circuit 55 obtains power from the tertiary coil T3 of the transformer T. The low-voltage connector 50a supplies power from the tertiary coil control circuit 55 to a low-voltage system battery BAT2.

[0030] The conversion circuit control unit 56 controls the multiple switching elements of the conversion circuit 51. Furthermore, the transformer control unit 57 controls the multiple switching elements of the primary coil control circuit 52 and the multiple switching elements of the secondary coil control circuit 54. The low voltage control unit 58 controls the multiple switching elements of the tertiary coil control circuit 55.

[0031] [Auxiliary inverter unit] The auxiliary inverter unit 60 of the inverter C functions as a DC-DC converter, and includes a first high-voltage connector 60 a, an auxiliary drive circuit 61 , a DC filter 62 , and an auxiliary control unit 63 .

[0032] The auxiliary drive circuit 61 includes a plurality of switching elements. The auxiliary control unit 63 controls the auxiliary drive circuit 61 to supply high-voltage power to auxiliary equipment such as the air conditioner 5 via the first high-voltage connector 60a. That is, the auxiliary inverter unit 60 includes a plurality of switching elements.

[0033] As shown in FIGS. 2 and 3, the auxiliary inverter unit 60 of the inverter C is disposed above the cooling plate 11 in the vertical direction Z.

[0034] [Main inverter unit] 4, the main inverter unit 65 of the inverter C has a second high-voltage connector 65a, a motor drive circuit 66 (an example of a first electronic component), and a smoothing capacitor 80. The motor drive circuit 66 has a plurality of switching elements and supplies power to the traction motor M.

[0035] The main inverter unit 65 functions to charge the main battery BAT1 (an example of a battery) by supplying the high-voltage power flowing between the OBC unit 50 and the auxiliary inverter unit 60 from the second high-voltage connector 65a. Therefore, in a broad sense, the OBC unit 50 and the main inverter unit 65 can be collectively referred to as an on-board charger.

[0036] In addition, the main inverter unit 65 converts the power from the main battery BAT1 into three-phase AC power using the motor drive circuit 66, controls the frequency, and supplies it to the traction motor M, thereby obtaining driving force from the traction motor M that enables the electric vehicle to run.

[0037] 2 and 3, the main inverter unit 65 including the motor drive circuit 66 and the smoothing capacitor 80 is disposed in contact with the upper surface 11a of the cooling plate 11. In this way, the main inverter unit 65 is cooled by the cooling plate 11. The motor drive circuit 66 is disposed adjacent to the smoothing capacitor 80.

[0038] [Control unit] The control unit D outputs control signals to the input / output control unit 45, the conversion circuit control unit 56, the transformer control unit 57, the low voltage control unit 58, and the auxiliary control unit 63. As shown in FIGS. 2 and 3, the control unit D is disposed above the cooling plate 11 and adjacent to the smoothing capacitor 80. As a result, the control unit D is cooled by the cooling plate 11.

[0039] Current Flow in Power Circuit Assembly As shown in FIG. 4, the power circuit assembly PE, under the control of the relay module 42, converts AC power from an AC power source (basically a commercial power source) supplied from outside the electric vehicle to an input connector 40a into DC power using a conversion circuit 51, and supplies AC of a set frequency generated by a primary coil control circuit 52 to the primary coil T1 side of the transformer T.

[0040] Furthermore, the high voltage power output to the secondary coil T2 side of the transformer T is extracted as high voltage DC power by the secondary coil control circuit 54 and is charged into the main battery BAT1 from the second high voltage connector 65a.

[0041] The high-voltage DC power charged in the main battery BAT1 is converted to three-phase AC power by the motor drive circuit 66, and the frequency is controlled before being supplied to the traction motor M. This allows the traction motor M to operate at a target rotation speed, enabling the electric vehicle to travel. In addition, the high-voltage DC power from the main battery BAT1 is DC-DC converted by the accessory drive circuit 61 and supplied to the air conditioner 5 and the like from the first high-voltage connector 60a.

[0042] In response to this, the low-voltage power output to the tertiary coil T3 side of the transformer T is converted into DC power by the tertiary coil control circuit 55 and charged into the system battery BAT2 from the low-voltage connector 50a. The power charged into the system battery BAT2 in this manner is supplied to the control device of the vehicle body and control devices of the electric vehicle.

[0043] Furthermore, under the control of the relay module 42, the power circuit assembly PE sequentially supplies power from the main battery BAT1 to the secondary coil control circuit 54, the transformer T, the primary coil control circuit 52, etc., thereby creating AC power similar to commercial power and outputting it from the output connector 40b.

[0044] [Configuration of smoothing capacitor] Next, the configuration of smoothing capacitor 80 according to this embodiment will be described with reference to Figures 5 and 6. Smoothing capacitor 80 includes a case 82, a plurality of capacitor elements 84, a pair of bus bars 86, and a sealing resin (not shown).

[0045] The case 82 is made of insulating resin and has a roughly rectangular parallelepiped outer shape. One of the six faces constituting the rectangular parallelepiped is an opening 82e, forming a space 82f inside. The other five faces excluding the opening 82e are walls that define the space 82f.

[0046] 2 and 3, the smoothing capacitor 80 is arranged by a method such as adhesion so that the case 82 faces (is in contact with) the upper surface 11a of the cooling plate 11. In addition, the smoothing capacitor 80 is arranged so that the opening 82e of the case 82 faces the motor drive circuit 66.

[0047] As shown in FIG. 5 , the smoothing capacitor 80 according to this embodiment includes a plurality (eight) of capacitor elements 84. The capacitor elements 84 are, for example, film capacitors. In this embodiment, four of the capacitor elements 84 are arranged in parallel along the axial direction L, and the four capacitor elements 84 are arranged in two rows along the axial-orthogonal direction Y. The plurality of capacitor elements 84 are inserted through an opening 82e of the case 82 together with a pair of bus bars 86 (described later) and held in a space 82f. Hereinafter, of the four capacitor elements 84 arranged in parallel in two rows along the axial-orthogonal direction Y while held in the case 82, the four capacitor elements 84 arranged in parallel closer to the opening 82e will be referred to as a first capacitor element unit 841, and the four capacitor elements 84 arranged in parallel farther from the opening 82e will be referred to as a second capacitor element unit 842.

[0048] Each capacitor element 84 has a first electrode and a second electrode on both end surfaces perpendicular to the vertical direction Z. The pair of bus bars 86 is made of a metal material with high conductivity, such as a copper alloy, and has a rectangular plate shape in a plan view. The pair of bus bars 86 is composed of a first bus bar 86a (an example of a bus bar) electrically connected to each first electrode of the eight capacitor elements 84 by a method such as soldering, and a second bus bar 86b (an example of a bus bar) electrically connected to each second electrode of the eight capacitor elements 84 by a method such as soldering. Hereinafter, the first bus bar 86a and the second bus bar 86b will be collectively referred to as bus bars 86. The bus bar 86 sandwiches and covers the eight capacitor elements 84, and electrically connects the eight capacitor elements 84 in parallel. Hereinafter, the eight capacitor elements 84 electrically connected to the first bus bar 86a and the second bus bar 86b will be referred to as a capacitor array 87.

[0049] As shown in FIGS. 5 and 6 , a first output terminal 86c, a second output terminal 86d, and an input terminal 86e extending from each of the first bus bar 86a and the second bus bar 86b (bus bar 86) are formed on the outer edges of the first bus bar 86a and the second bus bar 86b (bus bar 86) that are closer to the opening 82e. All of these terminals extend to the outside of the case 82 through the opening 82e of the case 82. In this embodiment, the first output terminal 86c is disposed on the outer edge of the bus bar 86 along the axial direction L, and the second output terminal 86d is disposed on the outer edge of the bus bar 86 along the axial-orthogonal direction Y. That is, the first output terminal 86c and the second output terminal 86d are disposed on two adjacent sides of the rectangular shape of the bus bar 86. The input terminal 86e is disposed on the outer edge of the bus bar 86 along the axial-orthogonal direction Y, opposite the side on which the second output terminal 86d is disposed. The second output terminal 86d is located farther from the input terminal 86e than the first output terminal 86c is located farther from the input terminal 86e.

[0050] The first output terminal 86c is a terminal connected to the motor drive circuit 66 (see also FIG. 4), and is branched into three so as to correspond to the U-phase, V-phase, and W-phase of the traction motor M. The first output terminal 86c branches into three at the first bus bar 86a, and then branches into three at the second bus bar 86b, and then further branches into two (for a total of six).

[0051] The second output terminal 86d is a terminal connected to the auxiliary inverter unit 60 (DC-DC converter) (see also FIG. 4), and is disposed on one side of a pair of side walls of the case 82. The input terminal 86e is a terminal connected to the main battery BAT1 via the second high-voltage connector 65a (see also FIG. 4), and is disposed on the other side of the pair of side walls of the case 82. Note that for each of the first output terminal 86c, the second output terminal 86d, and the input terminal 86e, an insulating sheet 86f is disposed between the terminal extending from the first bus bar 86a and the terminal extending from the second bus bar 86b to prevent a short circuit between the terminals.

[0052] The sealing resin (not shown) seals the space 82f while the capacitor array 87 is held in the space 82f of the case 82. Specifically, while the capacitor array 87 is held in the space 82f of the case 82, the molten sealing resin is filled into the space 82f and then hardened.

[0053] As shown in FIGS. 5 and 6 , a slit 86g is formed in the first bus bar 86a of the smoothing capacitor 80 of this embodiment. When the first bus bar 86a is held in the case 82, the slit 86g is formed at the boundary between the first output terminal 86c and the second output terminal 86d of the first bus bar 86a in a plan view. The slit 86g extends from the opening 82e side in the axial-orthogonal direction Y, i.e., along the side on which the second output terminal 86d is located, toward the first side Y1 in the axial-orthogonal direction, to the center of the side. That is, the slit length S of the slit 86g in this embodiment is half the length of the side of the first bus bar 86a along the axial-orthogonal direction Y. That is, on the side along the axial-orthogonal direction Y, the ratio of the slit length S to the remaining length R, which is the length of the non-slit portion, is 1:1. Hereinafter, the portion of the first bus bar 86a that branches off from the center of the side by the slit 86g and connects to the second output terminal 86d will be referred to as a branch path 86h. In addition, second bus bar 86b has slits 86g formed in the same locations as first bus bar 86a, and therefore detailed description of slits 86g of second bus bar 86b will be omitted.

[0054] In this embodiment, a current (power) from the main battery BAT1 is input to the input terminal 86e of the smoothing capacitor 80, and the same value of current is output from the first output terminal 86c and the second output terminal 86d. At this time, the current output from the first output terminal 86c (an example of a first output value; indicated by a dashed line in FIG. 6) flows mainly to the first capacitor element unit 841, and the current output from the second output terminal 86d (an example of a second output value; indicated by a dashed line in FIG. 6) flows mainly to the second capacitor element unit 842. This is because the slits 86g are formed in the bus bars 86 (the first bus bar 86a and the second bus bar 86b), and the current output from the second output terminal 86d flows through the branch path 86h. Specifically, because the slit 86g is formed at the boundary between the first output terminal 86c and the second output terminal 86d, in order for the current flowing through the first capacitor element unit 841 to be output from the second output terminal 86d, it cannot flow directly from the vicinity of the first output terminal 86c to the second output terminal 86d in the shortest distance, but must instead detour through the branch path 86h. However, the conductor resistance of the bus bar 86 from the first capacitor element unit 841 via the branch path 86h to the second output terminal 86d is greater than the conductor resistance of the bus bar 86 from the first capacitor element unit 841 to the first output terminal 86c. Therefore, the current flowing through the first capacitor element unit 841 is mainly output from the first output terminal 86c, which has a smaller conductor resistance of the bus bar 86. Conversely, the current output from the second output terminal 86d mainly flows through the second capacitor element unit 842.

[0055] In this way, by using the simple method of forming the slits 86g in the bus bar 86, the current output from the first output terminal 86c can be made to flow to the first capacitor element unit 841, and the current output from the second output terminal 86d can be made to flow to the second capacitor element unit 842. As described above, in this embodiment, the same current value is output from the first output terminal 86c and the second output terminal 86d. There is a positive correlation between the amount of heat generated by the capacitor element 84 and the current flowing through the capacitor element 84. Therefore, in the smoothing capacitor 80 of this embodiment, by appropriately setting the slit length S of the slits 86g in the bus bar 86, the amount of heat generated by the capacitor element 84 included in the first capacitor element unit 841 and the amount of heat generated by the capacitor element 84 included in the second capacitor element unit 842 can be made to be approximately equal. As a result, the respective lifetimes of the multiple capacitor elements 84 constituting the smoothing capacitor 80 can be made approximately equal.

[0056] [Modification of the first embodiment] Next, the configuration of a smoothing capacitor 80 according to a modification of the first embodiment will be described with reference to Fig. 7. In this modification, the slit length S of the slit 86g of the bus bar 86 differs from that of the first embodiment due to the difference between the current value output from the first output terminal 86c and the current value output from the second output terminal 86d of the bus bar 86. The other configuration is the same as in the first embodiment, so detailed description will be omitted.

[0057] In this modification, unlike the first embodiment, the value of the current output from the first output terminal 86c is twice the value of the current output from the second output terminal 86d. In this case, in order to equalize the amounts of heat generated by the capacitor elements 84 included in the first capacitor element unit 841 and the capacitor elements 84 included in the second capacitor element unit 842, it is necessary to output part of the current flowing through the second capacitor element unit 842 from the first output terminal 86c.

[0058] For this reason, in this modification, the ratio of the slit length S to the remaining length R is set to 2:1 on the side of the bus bar 86 along the axial-orthogonal direction Y. In this way, by extending the slit 86g to a part of the second capacitor element unit 842, a part of the current flowing through the second capacitor element unit 842 is output from the first output terminal 86c. This is because, when the slit 86g is extended to the second capacitor element unit 842, with respect to a part of the second capacitor element unit 842 that overlaps with the slit 86g in side view, the conductor resistance of the bus bar 86 from that part to the first output terminal 86c is smaller than the conductor resistance of the bus bar 86 from that part to the second output terminal 86d.

[0059] Conversely, when the value of the current output from first output terminal 86c is half the value of the current output from second output terminal 86d, the ratio of slit length S to remaining length R should be set to 1:2 on the side along the axis-orthogonal direction Y. In this way, by preventing a part of first capacitor element unit 841 from facing slit 86g, a part of the current flowing through first capacitor element unit 841 is output from second output terminal 86d.

[0060] As described above, by making the ratio between the current value output from the first output terminal 86c and the current value output from the second output terminal 86d and the ratio between the slit length S and the remaining length R on the side along the axially orthogonal direction Y equal, even if the current value output from the first output terminal 86c and the current value output from the second output terminal 86d are different, the heat generation amount of the capacitor element 84 included in the first capacitor element unit 841 and the heat generation amount of the capacitor element 84 included in the second capacitor element unit 842 can be made equal.

[0061] Second Embodiment Next, the configuration of a smoothing capacitor 80 according to a second embodiment will be described with reference to Fig. 8. In this embodiment, the position of the second output terminal 86d of the bus bar 86 is different from that of the first embodiment, and therefore the shape of the slit 86g of the bus bar 86 is also different from that of the first embodiment. As the other configurations are the same as those of the first embodiment, detailed description thereof will be omitted.

[0062] In the present embodiment, the second output terminal 86d is arranged on the outer edge of the bus bar 86 along the axial direction L, on the outer edge opposite to the side on which the first output terminal 86c is arranged. That is, the first output terminal 86c and the second output terminal 86d are arranged on two sides facing each other. In the present embodiment as well, the distance between the second output terminal 86d and the input terminal 86e is greater than the distance between the first output terminal 86c and the input terminal 86e.

[0063] In the present embodiment, when the bus bar 86 is held in the case 82, the slit 86g of the bus bar 86 extends in a plan view from the side of the opening 82e at the boundary between the first output terminal 86c and the second output terminal 86d in the axial orthogonal direction Y, i.e., along the side on which the second output terminal 86d is arranged, toward the first side Y1 in the axial orthogonal direction, to near the boundary between the first capacitor element unit 841 and the second capacitor element unit 842, bends by 90 degrees from there, and extends along the axial direction L between the side on which the first output terminal 86c is arranged and the side on which the second output terminal 86d is arranged, to near the boundary between the second capacitor element 84 and the third capacitor element 84 of the four capacitor elements 84 arranged in parallel. That is, the slit 86g in the present embodiment has an L-shape in which half the length of the side of the first bus bar 86a along the axial orthogonal direction Y is connected to half the length of the side along the axial direction L. In this embodiment, the first output terminal 86c and the second output terminal 86d output currents of the same value.

[0064] In the present embodiment, the branch path 86h formed by the slit 86g is folded back at the opening 82e of the case 82 and extends outside the case 82 in the axial-orthogonal direction Y to the second output terminal 86d. Even with this shape, the heat generation amount of the capacitor element 84 included in the first capacitor element unit 841 and the heat generation amount of the capacitor element 84 included in the second capacitor element unit 842 can be made equal. Note that, in the present embodiment, the same value of current is output from the first output terminal 86c and the second output terminal 86d. However, the current value output from the first output terminal 86c and the current value output from the second output terminal 86d may be different. In this case, this can be addressed by changing the slit length S1 of the portion of the slit 86g extending along the axial direction L.

[0065] Third Embodiment Next, the configuration of a smoothing capacitor 80 according to a third embodiment will be described with reference to Fig. 9. In this embodiment, the position of the opening 82e of the case 82 is different from that of the first embodiment, being located on the lower side in the drawing, and accordingly, the arrangement of the first output terminal 86c, the second output terminal 86d, and the input terminal 86e of the bus bar 86 has been changed. As the other configurations are the same as those of the first embodiment, detailed description will be omitted.

[0066] In this embodiment, a first output terminal 86c, a second output terminal 86d, and an input terminal 86e are formed on the outer edge of the bus bar 86 closer to the opening 82e. All of these terminals extend from the opening 82e to the outside of the case 82. In this embodiment, the first output terminal 86c is disposed on the outer edge of the bus bar 86 along the axial direction L near the opening 82e, and the second output terminal 86d is disposed on the outer edge of the bus bar 86 along the axial direction Y. That is, the first output terminal 86c and the second output terminal 86d are disposed on two adjacent sides of the rectangular bus bar 86. The input terminal 86e is disposed on the outer edge of the bus bar 86 along the axial direction Y, opposite the side on which the second output terminal 86d is disposed. The second output terminal 86d is located farther from the input terminal 86e than the first output terminal 86c is located on the input terminal 86e. The smoothing capacitor 80 of this embodiment has a shape obtained by rotating the configuration of the first embodiment (see FIG. 6) by 180 degrees and swapping the positions of the input terminal 86e and the second output terminal 86d.

[0067] In the smoothing capacitor 80 of this embodiment, the first output terminal 86c and the second output terminal 86d output currents of the same value. Therefore, similar to the first embodiment, the slit 86g formed in the bus bar 86 of this embodiment is formed at the boundary between the first output terminal 86c and the second output terminal 86d of the first bus bar 86a in a plan view while the bus bar 86 is held in the case 82, from the side of the opening 82e in the axis-orthogonal direction Y, i.e., along the side on which the second output terminal 86d is located, to the center of the side. This allows the smoothing capacitor 80 of this embodiment to also have the amount of heat generated by the capacitor element 84 included in the first capacitor element unit 841 and the amount of heat generated by the capacitor element 84 included in the second capacitor element unit 842 be equal to each other.

[0068] In this embodiment, the same value of current is output from the first output terminal 86c and the second output terminal 86d, but the current value output from the first output terminal 86c and the current value output from the second output terminal 86d may be different. In this case, as in the modified example of the first embodiment, this can be addressed by changing the slit length S of the slit 86g.

[0069] [Another embodiment] The present disclosure may be configured as follows in addition to the above-described embodiments (common numbers and symbols as in the embodiments are used to designate components having the same functions as in the embodiments).

[0070] (1) In the above embodiment and its modified examples, by making the ratio between the first output value, which is the current value output from the first output terminal 86c, and the second output value, which is the current value output from the second output terminal 86d, and the ratio between the slit length S and the remaining length R on the side along the axially orthogonal direction Y equal, it has been explained that even if the first output value and the second output value are different, the heat generation amount of the capacitor element 84 included in the first capacitor element unit 841 and the heat generation amount of the capacitor element 84 included in the second capacitor element unit 842 can be made equal, but this is not limited to this.

[0071] The conductor resistance of bus bar 86 varies depending on the material, plate thickness, shape, etc. of bus bar 86, and therefore the ratio between the first output value and the second output value and the ratio between the slit length S and the remaining length R on the side along the axial orthogonal direction Y do not necessarily have to be the same. In other words, in order to make the heat generation amounts of the capacitor elements 84 included in first capacitor element unit 841 and the heat generation amounts of the capacitor elements 84 included in second capacitor element unit 842 equal, the ratio between the slit length S and the remaining length R of slit 86g on the side along the axial orthogonal direction Y can be set to an optimal ratio based on the ratio between the first output value and the second output value.

[0072] (2) In the above embodiment and its modified examples, only one slit 86g is formed in the bus bar 86, but multiple slits 86g may be formed as long as the heat generation amount of the capacitor element 84 included in the first capacitor element unit 841 and the heat generation amount of the capacitor element 84 included in the second capacitor element unit 842 can be made equal.

[0073] (3) In the above embodiment and its modified examples, the slit 86g is formed between the first output terminal 86c and the second output terminal 86d of the bus bar 86. However, the slit 86g may be formed between the input terminal 86e and the first output terminal 86c as long as the amount of heat generated by the capacitor elements 84 included in the first capacitor element unit 841 and the amount of heat generated by the capacitor elements 84 included in the second capacitor element unit 842 can be made equal. Alternatively, the slit 86g may be formed both between the first output terminal 86c and the second output terminal 86d and between the input terminal 86e and the first output terminal 86c.

[0074] In the above-described embodiment, the following configurations are envisioned.

[0075] <1> The capacitor (80) includes a plurality of capacitor elements (84) and a pair of bus bars (86a, 86b) that electrically connect the plurality of capacitor elements (84) in parallel. Each of the pair of bus bars (86a, 86b) includes an input terminal (86e) that can input power from a battery (BAT1) to the plurality of capacitor elements (84), a first output terminal (86c) that outputs power from the plurality of capacitor elements (84) to the first electronic component (66), a second output terminal (86d) that outputs power from the plurality of capacitor elements (84) to the second electronic component (60) and is located farther from the input terminal (86e) than the first output terminal (86c), and a slit (86g) that is formed between the first output terminal (86c) and the second output terminal (86d) and that diverts a current path that flows from the input terminal (86e) to the second output terminal (86d).

[0076] A current supplied from the input terminal 86e to the capacitor 80 flows through the bus bars 86a, 86b via a current path with low conductor resistance to the output terminal and is output from the output terminal. In other words, current flows intensively through the capacitor elements 84 connected to the bus bars 86a, 86b at locations where the current path with low conductor resistance to the output terminal exists, and current does not flow easily through the capacitor elements 84 connected to the bus bars 86a, 86b at locations where the current path with high conductor resistance to the output terminal exists. In this configuration, the slit 86g is provided between the first output terminal 86c and the second output terminal 86d. Therefore, the capacitor elements 84 connected to the bus bars 86a, 86b at locations where the current path with low conductor resistance to the first output terminal 86c exists and the capacitor elements 84 connected to the bus bars 86a, 86b at locations where the current path with low conductor resistance to the second output terminal 86d exist are different capacitor elements 84.

[0077] Specifically, for the plurality of capacitor elements 84 arranged near the first output terminal 86c, the current path from the plurality of capacitor elements 84 to the second output terminal 86d is long because it needs to be detoured by the slits 86g. Therefore, the conductor resistance of the bus bars 86a, 86b from the plurality of capacitor elements 84 arranged near the first output terminal 86c to the second output terminal 86d is large, and therefore the current flowing through the plurality of capacitor elements 84 arranged near the first output terminal 86c is output almost entirely from the first output terminal 86c. Conversely, for the plurality of capacitor elements 84 arranged far from the first output terminal 86c, the current path from the plurality of capacitor elements 84 to the second output terminal 86d is shorter than the current path to the first output terminal 86c because it does not need to be detoured by the slits 86g. Therefore, the conductor resistance of the bus bars (86a, 86b) from the plurality of capacitor elements (84) arranged far from the first output terminal (86c) to the second output terminal (86d) is reduced, and the current flowing through the plurality of capacitor elements (84) arranged far from the first output terminal (86c) is output almost entirely from the second output terminal (86d).

[0078] In this way, the current flowing through the plurality of capacitor elements (84) arranged at different locations is output from different output terminals, and therefore, it is possible to pass the current through all of the plurality of capacitor elements (84). As a result, by appropriately setting the slit length (S) of the slit (86g), it is possible to make the amount of heat generated by each of the plurality of capacitor elements (84) through which the current output from the first output terminal (86c) flows equal to the amount of heat generated by each of the plurality of capacitor elements (84) through which the current output from the second output terminal (86d) flows.

[0079] <2> the above <1> In the capacitor (80) described above, it is preferable that when the pair of bus bars (86a, 86b) have a rectangular shape in a plan view and the first output terminal (86c) and the second output terminal (86d) are arranged on two adjacent sides, the slit (86g) is formed along the side on which the second output terminal (86d) is arranged.

[0080] According to this configuration, the slit (86g) is formed along one side on which the second output terminal (86d) is arranged, so that even when the first output terminal (86c) and the second output terminal (86d) are arranged on two adjacent sides, the plurality of capacitor elements (84) through which the current output from the first output terminal (86c) flows can be different from the plurality of capacitor elements (84) through which the current output from the second output terminal (86d) flows. This allows current to flow through all of the plurality of capacitor elements (84), making it possible to equalize the amount of heat generated by each of the plurality of capacitor elements (84).

[0081] <3> the above <1> In the capacitor (80) described above, it is preferable that when the pair of bus bars (86a, 86b) have a rectangular shape in plan view and the first output terminal (86c) and the second output terminal (86d) are arranged on two opposing sides, the slit (86g) is formed between the two sides and along the two sides.

[0082] According to this configuration, the first output terminal (86c) and the second output terminal (86d) are arranged on two opposing sides, and the slits (86g) are formed along the two sides between the two sides, so that the plurality of capacitor elements (84) through which the current output from the first output terminal (86c) flows and the plurality of capacitor elements (84) through which the current output from the second output terminal (86d) flows can be made different near the input terminal (86e). This makes it possible to more effectively pass current through all of the plurality of capacitor elements (84), and to equalize the amount of heat generated by each of the plurality of capacitor elements (84).

[0083] <4> the above <1> from <3> In the capacitor (80) described in any one of the above, it is preferable that the slit length (S) of the slit (86g) is set based on the ratio between the first output value output from the first output terminal (86c) and the second output value output from the second output terminal (86d).

[0084] According to this configuration, the slit length (S) of the slit (86g) can be appropriately set based on the ratio between the first output value output from the first output terminal (86c) and the second output value output from the second output terminal (86d), thereby making it possible to equalize the values ​​of current flowing through the plurality of capacitor elements (84), thereby making it possible to equalize the amounts of heat generated by the plurality of capacitor elements (84). [Industrial Applicability]

[0085] The present disclosure can be used in capacitors. [Explanation of symbols]

[0086] 60: auxiliary inverter unit (second electronic component), 66: motor drive circuit (first electronic component), 80: smoothing capacitor (capacitor), 84: capacitor element, 86a: first bus bar (bus bar), 86b: second bus bar (bus bar), 86c: first output terminal, 86d: second output terminal, 86e: input terminal, 86g: slit, BAT1: main battery (battery), S: slit length, S1: slit length

Claims

1. a plurality of capacitor elements; a pair of bus bars that electrically connect the plurality of capacitor elements in parallel, Each of the pair of bus bars is an input terminal capable of inputting power from a battery to the plurality of capacitor elements; a first output terminal for outputting power from the plurality of capacitor elements to a first electronic component; a second output terminal that outputs power from the plurality of capacitor elements to a second electronic component and is located farther from the input terminal than the first output terminal; a slit formed between the first output terminal and the second output terminal, for diverting a current path flowing from the input terminal to the second output terminal; A capacitor including:

2. The pair of bus bars have a rectangular shape in a plan view, 2. The capacitor according to claim 1, wherein when the first output terminal and the second output terminal are arranged on two adjacent sides, the slit is formed along one side on which the second output terminal is arranged.

3. The pair of bus bars have a rectangular shape in a plan view, 2. The capacitor according to claim 1, wherein when the first output terminal and the second output terminal are arranged on two opposing sides, the slit is formed between the two sides and along the two sides.

4. 4. The capacitor according to claim 1, wherein the slit length of the slit is set based on a ratio between a first output value output from the first output terminal and a second output value output from the second output terminal.

Images