Power conversion device

Abstract

To provide a power conversion device that suppresses variations in temperature of a heat generating component after cooling and improves a degree of freedom in design of a cooling passage in a cooling unit.SOLUTION: A power conversion device 10 includes: a circuit board 20 whose one surface is disposed along a vertical direction; a heat generating component 30 mounted on one surface of the circuit board 20; and a cooling unit 40 disposed on the other surface of the circuit board 20. The cooling unit 40 includes a main passage 41 having a path connecting an inlet portion 411 and an outlet portion 412; and a sub-passage 42 that bypasses and connects part of the main passage 41. The main passage 41 includes a return portion 451, a first portion 452, and a second portion 453. The sub-passage 42 connects the first portion 452 and the second portion 453 in a vertical direction while bypassing at least the return portion 451 in the path of the main passage 41.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power conversion device that converts and outputs input power.

Background Art

[0002] A cooling structure is known in which heat-generating components are mounted on the surface of a substrate and a cooling unit is disposed on the back surface of the substrate. By circulating a coolant through the cooling unit, the heat-generating components can be cooled.

[0003] For example, Patent Document 1 discloses a cooling structure for an electric drive unit (EDU) mounted on a hybrid vehicle. Specifically, Patent Document 1 discloses an electric drive unit assembly in which an electric drive unit and an integrated power electronics unit (IPE) are integrated. Further, the integrated power electronics unit of Patent Document 1 incorporates an internal cooling system. The internal cooling system includes a main case having a cooling passage and a cooling cover located on the upper surface of the main case. Heat-generating components such as a power conversion module are disposed on the cooling cover. The internal cooling system cools various heat-generating components of the integrated power electronics unit by circulating a coolant through the cooling passage.

[0004] Further, Patent Document 1 discloses a horizontal layout in which the planar integrated power electronics unit is horizontally disposed above the electric drive unit, and a vertical layout in which the integrated power electronics unit is vertically disposed beside the electric drive unit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, a large number of heat-generating components are mounted on the substrate of a power conversion device such as an inverter. Therefore, in the power conversion device, it is required to cool the large number of heat-generating components as evenly as possible. On the other hand, in the case of a direct water cooling system in which the coolant directly contacts the substrate in the power conversion device, if the cooling passage through which the coolant flows is not properly designed, the coolant will not flow uniformly. Therefore, in order to cool the large number of heat-generating components as evenly as possible, it is necessary to design the cooling passage so that the coolant flows uniformly in the cooling passage.

[0007] Moreover, for example, in the case of a vertical arrangement in which one surface of the substrate is arranged along the vertical direction, air may stay in the cooling passage through which the coolant flows. When air stays in the cooling passage, the heat transfer coefficient of the staying portion decreases, so the cooling performance of that portion deteriorates. Therefore, variations in the temperature of the heat-generating components after cooling are likely to occur. Therefore, a design of the cooling passage that suppresses the stay of air is also required.

[0008] Considering both the uniformity of the flow of the coolant and the stay of air in this way, the degree of freedom in the design of the cooling passage is limited.

[0009] Therefore, there is a need for a power conversion device that can suppress variations in the temperature of the heat-generating components after cooling and increase the degree of freedom in the design of the cooling passage even when the substrate is vertically arranged.

[0010] An object of the present invention is to realize a configuration capable of suppressing variations in the temperature of heat-generating components after cooling and improving the degree of freedom in the design of the cooling passage in the cooling unit in a power conversion device having a cooling unit including a vertically arranged circuit board and a cooling passage for cooling the heat-generating components of the circuit board.

Means for Solving the Problems

[0011] The inventors of the present invention have earnestly studied a configuration that can suppress variations in the temperature of heat-generating components after cooling and improve the design freedom of the cooling passages in the cooling unit in a power conversion device having a vertically arranged circuit board and a cooling unit having cooling passages for cooling the heat-generating components of the circuit board. As a result, the inventors have conceived of the following configuration.

[0012] A power conversion device according to an embodiment of the present invention includes a circuit board having one surface arranged along the vertical direction, heat-generating components mounted on one surface of the circuit board, and a cooling unit arranged on the other surface of the circuit board. The cooling unit has an inlet portion to which a coolant is supplied and an outlet portion for discharging the coolant inside thereof, and has a main passage extending along the other surface of the circuit board and connecting the inlet portion and the outlet portion, and a sub passage that bypasses and connects a part of the path of the main passage. The path has at least one turning portion located between the inlet portion and the outlet portion, a first portion located closer to the inlet portion than the turning portion, and a second portion located closer to the outlet portion than the turning portion and located below the first portion. The sub passage bypasses at least the turning portion of the path of the main passage and connects the first portion and the second portion in the vertical direction.

[0013] In the above-described configuration, the circuit board is arranged such that one surface thereof is along the vertical direction. Therefore, the circuit board is arranged in a so-called vertical orientation. Further, in the above-described configuration, the cooling unit for cooling the heat-generating components mounted on one surface of the circuit board is arranged on the other surface of the circuit board. Therefore, the coolant flowing in the main passage extending along the other surface of the circuit board inside the cooling unit flows in the vertical direction inside the cooling unit.

[0014] In the cooling unit, part of the coolant flows not only in the main passage but also in a sub-passage that bypasses and connects a part of the main passage. Therefore, the range that can be cooled by the cooling unit can be expanded. Thus, variations in temperature in the circuit board and the heat-generating components can be suppressed.

[0015] Also, when the flow of the coolant is stopped in the main passage of the cooling unit, air accumulates in the main passage of the cooling unit. In contrast, the sub-passage that vertically connects the first part and the second part allows the air staying in the second part to move to the first part located above the second part. Thereby, when the circuit board is placed vertically, it is possible to prevent air from staying in the second part and degrading the cooling performance of the cooling unit.

[0016] In this way, by providing the sub-passage, it is possible to suppress the occurrence of variations in temperature or air retention in the circuit board and the heat-generating components. Thus, in the cooling unit for cooling a vertically placed circuit board, the degree of freedom in designing the main passage can be improved.

[0017] As described above, in a power conversion device having a vertically placed circuit board and a cooling unit having a cooling passage for cooling the heat-generating components of the circuit board, it is possible to suppress variations in temperature of the heat-generating components after cooling and to realize a configuration capable of improving the degree of freedom in designing the cooling passage in the cooling unit.

[0018] From another perspective, it is preferable that the power conversion device of the present invention includes the following configuration. The flow area of the sub-passage is smaller than the flow area of the main passage.

[0019] In the above-described configuration, the amount of coolant flowing into or out of the sub-passage from the main passage can be suppressed. Thereby, it is possible to suppress the flow of the coolant flowing through the sub-passage from interfering with the flow of the coolant flowing through the main passage.

[0020] From another perspective, it is preferable that the power conversion device of the present invention includes the following configuration. In the main passage, the second portion has a bent portion that extends and bends along the other surface of the circuit board. The sub-passage connects the first portion and the bent portion of the second portion.

[0021] As a result, in the bent portion of the second portion, the flow rate of the cooling liquid becomes gentle. Therefore, in the bent portion of the second portion, the dynamic pressure of the cooling liquid is lower than that of the linearly extending portion in the second portion. The sub-passage connects the first portion and the bent portion where the dynamic pressure is low in the second portion. Therefore, it is difficult for the cooling liquid to flow from the first portion toward the bent portion of the second portion in the sub-passage. Thus, the amount of the cooling liquid flowing in the sub-passage can be suppressed, and the cooling liquid can flow smoothly into the main passage.

[0022] From another perspective, it is preferable that the power conversion device of the present invention includes the following configuration. At least one of the inlet portion or the outlet portion is located above the cooling portion.

[0023] As a result, air is easily discharged to the outside of the cooling portion through at least one of the inlet portion or the outlet portion located above the cooling portion. Thus, a power conversion device in which an air pocket is less likely to occur in the cooling portion can be realized.

[0024] From another perspective, it is preferable that the power conversion device of the present invention includes the following configuration. The circuit board includes a metal substrate.

[0025] As a result, the thermal conductivity of the circuit board is improved compared to the case where the circuit board is made of resin. Thus, the heat dissipation performance of the circuit board is improved.

[0026] The technical terms used in this specification are used only for the purpose of defining specific embodiments, and are not intended to limit the invention by these technical terms.

[0027] As used herein, "and / or" includes all combinations of one or more of the associated listed components.

[0028] As used herein, the use of "including", "comprising", "having" and their variants identifies the presence of the described features, steps, operations, elements, components, and / or their equivalents, but may include one or more of steps, actions, elements, components, and / or groups thereof.

[0029] As used herein, "attached", "connected", "coupled", and / or their equivalents are used in a broad sense and include both "direct and indirect" attachment, connection and coupling. Further, "connected" and "coupled" are not limited to physical or mechanical connections or couplings and may include direct or indirect electrical connections or couplings.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0031] Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0032] In the description of the present invention, it is understood that a number of techniques and steps are disclosed. Each of these has its own individual benefits and can also be used in combination with one or more, or in some cases all, of the other disclosed techniques.

[0033] Therefore, for clarity, in the description of the present invention, we refrain from repeating all possible combinations of the individual steps needlessly. However, this specification and the claims should be read with the understanding that all such combinations are within the scope of the present invention.

[0034] In this specification, embodiments of a power conversion device according to the present invention will be described.

[0035] In the following description, numerous specific examples are given to provide a complete understanding of the present invention. However, it is clear to those skilled in the art that the present invention can be practiced without these specific examples.

[0036] Therefore, the following disclosure should be considered as illustrative of the present invention and is not intended to limit the present invention to the specific embodiments shown in the following drawings or description.

[0037] [Power conversion device] In this specification, a power conversion device is a device that converts and outputs input power. The power conversion device has a power conversion circuit that converts the input power. The power conversion circuit has, for example, a plurality of switching elements. The switching elements are driven and controlled by a control circuit formed on a control board. The power conversion circuit may be a circuit having components other than the switching elements as long as it has a configuration capable of converting power.

[0038] [Vertical direction] In this specification, the vertical direction of the power conversion device means the vertical direction in the state where the power conversion device is installed. For example, when the power conversion device is attached to an attachment target, the vertical direction of the power conversion device coincides with the vertical direction of the attachment target. That one surface of a circuit board is arranged along the vertical direction means that the one surface is arranged parallel or inclined with respect to the vertical direction of the attachment target.

[0039] [Moving body] In this specification, a moving body means a structure configured to be movable by power output from a power source. The moving body has a power source. The power source includes internal combustion engines such as engines, motors, actuators, and the like. A power conversion device is attached to the moving body. The moving body includes not only vehicles that can carry people but also transportation equipment for transporting luggage and moving bodies that cannot carry people or luggage. The moving body can move on the ground, on water, underwater, or in the air. The moving body includes, for example, motorcycles, four-wheel vehicles, ATVs (all-terrain vehicles), ROVs (Recreational Off-highway Vehicles), drones, water vehicles, and the like.

[0040] [Circuit board] In this specification, a circuit board is, for example, a board on which components for performing power conversion in a power conversion device are mounted. A power conversion circuit is formed on the circuit board. A control circuit may be formed on the circuit board. The control circuit may be formed on the circuit board or on a board separate from the circuit board.

[0041] [Power conversion circuit] In this specification, a power conversion circuit means a circuit that converts and outputs input power. The power conversion circuit includes, for example, switching elements driven and controlled by a control circuit.

[0042] [Control circuit] In this specification, a control circuit means a circuit that generates a control signal for controlling the drive of a power conversion circuit and outputs it to the power conversion circuit. When the power conversion circuit has a plurality of switching elements, the control circuit generates a control signal for controlling the drive of the plurality of switching elements and outputs it to the power conversion circuit.

[0043] [Heat-generating component] In this specification, a heat-generating component refers to a component that is mounted on a circuit board in a power conversion device and generates heat during the power conversion operation of the power conversion device. The heat-generating component includes, for example, a power semiconductor, a capacitor, or an electronic component.

[0044] [Connect in a bypass manner] In this specification, when a sub-passage bypasses and connects a part of the main passage, it means that the length of the sub-passage is shorter than the length from the connection part between the first part of the main passage and the sub-passage to the connection part between the second part of the main passage and the sub-passage.

[0045] [Folding part] In this specification, the folding part means a part where the flow direction of the coolant changes in the opposite direction in the main passage of the cooling part. In this specification, in the folding part, for example, the flow direction of the coolant after passing through the folding part changes by 90° or more with respect to the flow direction of the coolant entering the folding part. In the folding part, the flow direction of the coolant may change by 180°. [Advantages of the Invention]

[0046] According to an embodiment of the present invention, in a power conversion device having a vertically arranged circuit board and a cooling part having a cooling passage for cooling the heat-generating components of the circuit board, it is possible to suppress the variation in the temperature of the heat-generating components after cooling and to realize a configuration capable of improving the design freedom of the cooling passage in the cooling part. [Brief Description of the Drawings]

[0047]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0048] Hereinafter, the embodiments will be described with reference to the drawings. In each figure, the same reference numerals are given to the same parts, and the description of the same parts will not be repeated. Note that the dimensions of the constituent members in each figure do not faithfully represent the dimensions of the actual constituent members and the dimensional ratios of the constituent members.

[0049] Hereinafter, in the figures, the arrow FR indicates one of the depth directions of the power conversion devices 10 and 11. The arrow RR in the figures indicates the other depth direction of the power conversion devices 10 and 11. The arrow LF in the figures indicates one of the width directions of the power conversion devices 10 and 11. The arrow RG in the figures indicates the other width direction of the power conversion devices 10 and 11. The arrow UP in the figures indicates the upward direction of the power conversion devices 10 and 11. The arrow DW in the figures indicates the downward direction of the power conversion devices 10 and 11.

[0050] Also, the arrow VFR in the figures indicates the forward direction of the moving body. The arrow VRR in the figures indicates the rearward direction of the moving body. The arrow VLF in the figures indicates one of the width directions of the moving body. The arrow VRG in the figures indicates the other width direction of the moving body. The arrow VUP in the figures indicates the upward direction of the moving body. The arrow VDW in the figures indicates the downward direction of the moving body.

[0051] The moving body includes, for example, a two-wheeled vehicle, a four-wheeled vehicle, an ATV (all-terrain vehicle), an ROV (Recreational Off-highway Vehicle), a drone, a water vehicle, and the like. Further, one of the thickness directions of the circuit boards 20 and 200 coincides with one of the depth directions FR of the power conversion devices 10 and 11, and the other of the thickness directions of the circuit boards 20 and 200 coincides with the other of the depth directions RR of the power conversion devices 10 and 11.

[0052] [Embodiment 1] (Schematic Configuration of Power Conversion Device) FIG. 1 is a schematic perspective view showing a schematic configuration of a power conversion device 10 according to Embodiment 1. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a cross-sectional view showing a case where the flow of the coolant is stopped in the cooling unit 40. In FIG. 2, when the power conversion device 10 is viewed in the depth direction, the position where the circuit board 20 and the heat-generating component 30 overlap is represented by a two-dot chain line.

[0053] As shown in FIG. 1, the power conversion device 10 is a device that converts the power supplied from a power source such as the battery B1 and supplies it to an external load. Further, the power conversion device 10 is attached to an attachment target such as the moving body. Specifically, the power conversion device 10 is attached to the battery B1 along the side wall B12 of the battery B1 mounted on the moving body by the bracket B11. That is, the power conversion device 10 is located in one VLF in the width direction of the moving body rather than the battery B1. The power conversion device 10 and the battery B1 are attached to the moving body so that the vertical directions of the power conversion device 10 and the battery B1 coincide with the vertical direction of the moving body. That is, the vertical direction of the power conversion device 10 coincides with the vertical direction of the moving body. Also, one FR in the depth direction of the power conversion device 10 coincides with one VLF in the width direction of the moving body. The other RR in the depth direction of the power conversion device 10 coincides with the other VRG in the width direction of the moving body. One LF in the width direction of the power conversion device 10 coincides with the forward direction VFR of the moving body. The other RG in the depth direction of the power conversion device 10 coincides with the rearward direction VRR of the moving body. As shown in FIGS. 1 to 3, the power conversion device 10 includes a circuit board 20, a heat-generating component 30, and a cooling unit 40.

[0054] The circuit board 20 is, for example, a plate-shaped substrate having a circuit that converts the input power and outputs it. For example, a power conversion circuit having a switching element is formed on the circuit board 20. The circuit board 20 converts the DC power supplied from a power source such as a battery into AC power in response to the drive control of the switching element by a control circuit (not shown) and outputs it to an external load (not shown). The external load is, for example, a motor or the like of the moving body to be attached. The control circuit may be included in the circuit board 20 or may be included in a control board separate from the circuit board 20. One surface 21 of the circuit board 20 is arranged along the vertical direction of the moving body. That is, the circuit board 20 is arranged so that one surface 21 is parallel to the vertical direction of the moving body.

[0055] The heat-generating component 30 is a component mounted on one surface 21 of the circuit board 20. The heat-generating component 30 constitutes the power conversion circuit. The heat-generating component 30 is a component that generates heat during power conversion, such as a power semiconductor, a capacitor, or an electronic component. The heat-generating component 30 may be a diode, a transistor, an integrated circuit, a resistor, a coil, a transformer, or the like.

[0056] The cooling unit 40 cools the heat-generating component 30 mounted on the circuit board 20. The cooling unit 40 can be constituted by a water-cooled cooler having a cooling passage through which a coolant flows. Note that the cooling unit 40 may or may not have a cooling plate. The cooling unit 40 is disposed on the other surface 22 of the circuit board 20. The cooling unit 40 has a main passage 41 and a sub-passage 42.

[0057] The main passage 41 has an inlet portion 411 and an outlet portion 412.

[0058] The inlet portion 411 is connected to an external (not shown) pump or the like that sends out the coolant, and the coolant is supplied from the pump during the operation of the cooling unit 40. The inlet portion 411 is located at the upper part of the cooling unit 40. The outlet portion 412 discharges the coolant to the outside. The outlet portion 412 is located at the lower part of the cooling unit 40. The inlet portion 411 and the outlet portion 412 are located at one end LF in the width direction. Note that a known antifreeze or the like can be used as the coolant.

[0059] The main passage 41 extends along the other surface 22 of the circuit board 20 from the inlet portion 411 toward the outlet portion 412. The main passage 41 is formed so as to overlap all the heat-generating components 30 mounted on one surface 21 of the circuit board 20 when the power conversion device 10 is viewed in the depth direction. Furthermore, the main passage 41 extends without intersecting and has a one-piece labyrinth structure from above to below. Also, in the main passage 41, the coolant flows only in one direction.

[0060] The main passage 41 has at least one folding portion 451, a first portion 452, and a second portion 453.

[0061] The folding portion 451 is a portion where the direction of the flow of the coolant in the main passage 41 changes when viewed in the depth direction. The folding portion 451 is bent so as to fold back. Thereby, the folding portion 451 connects the first portion 452 and the second portion 453 so that the second portion 453 is positioned below the first portion 452. Specifically, the folding portion 451 has a bent portion 451a and a bent portion 451b. Thus, the folding portion 451 may have two bent portions 451a and 451b. Due to the two bent portions 451a and 451b, the flow of the coolant changes from the other side RG in the width direction to the one side LF in the width direction when viewed in the depth direction.

[0062] The first portion 452 is located at a position closer to the inlet portion 411 than the folding portion 451 in the main passage 41. In the example shown in FIG. 2, the first portion 452 extends in the width direction. The first portion 452 is connected to the bent portion 451a located above the folding portion 451.

[0063] The second portion 453 is located at a position closer to the outlet portion 412 than the folding portion 451 in the main passage 41 and is located below the first portion 452. In the example shown in FIG. 2, the second portion 453 extends in the width direction. The second portion 453 is connected to the bent portion 451b located below the folding portion 451.

[0064] Thus, in the folding portion 451, the main passage 41 is folded back. Thereby, when the coolant flows from the first portion 452 to the second portion 453, the direction in which the coolant flows changes to the reverse direction.

[0065] The sub-passage 42 bypasses and connects a part of the main passage 41. In the example shown in FIG. 2, the sub-passage 42 bypasses at least the folding portion 451 of the main passage 41 and connects the first portion 452 and the second portion 453 in the vertical direction. The length of the sub-passage 42 is shorter than the length from the connection portion between the first portion 452 of the main passage 41 and the sub-passage 42 to the connection portion between the second portion 453 of the main passage 41 and the sub-passage 42.

[0066] In the above configuration, the circuit board 20 is arranged such that one surface 21 thereof extends along the vertical direction. Therefore, the circuit board 20 is arranged in a so-called vertical orientation. Further, in the above configuration, a cooling unit 40 for cooling the heat-generating component 30 mounted on one surface 21 of the circuit board 20 is arranged on the other surface 22 of the circuit board 20. Also, the main passage 41 extends in the vertical direction. For this reason, the inlet portion 411 of the main passage 41 is located above the cooling unit 40, and the outlet portion 412 is located below the cooling unit 40. Therefore, the coolant flowing in the main passage 41 of the cooling unit 40 flows in the vertical direction within the cooling unit 40.

[0067] When flowing the coolant into the main passage 41 of the cooling unit 40, as indicated by the solid-line arrow in FIG. 2, while the coolant flows in the main passage 41, as indicated by the broken-line arrow in the cooling unit 40 in FIG. 2, a part of the coolant also flows into the sub-passage 42 that bypasses and connects a part of the main passage 41. For this reason, the range that can be cooled by the cooling unit 40 can be expanded. Thus, the variation in temperature in the circuit board 20 and the heat-generating component 30 can be suppressed.

[0068] Also, when the flow of the coolant stops in the main passage 41 of the cooling unit 40, as shown in FIG. 3, air AR1 accumulates in the main passage 41 of the cooling unit 40. In contrast, the sub-passage 42 that connects the first portion 452 and the second portion 453 in the vertical direction allows the air AR1 staying in the second portion 453 to move to the first portion 452 located above the second portion 453, as indicated by the white arrow. The air AR1 that has moved to the first portion 452 is discharged to the outside from the inlet portion 411. Thereby, when the circuit board 20 is vertically placed, it is possible to prevent the air AR1 from staying in the second portion 453 and degrading the cooling performance of the cooling unit 40.

[0069] In this way, by providing the sub-passage 42 with respect to the main passage 41, it is possible to suppress variations in temperature in the circuit board 20 and the heat-generating components 30 or the retention of the air AR1 or the like. Therefore, in the cooling unit 40 that cools the vertically arranged circuit board 20, the degree of freedom in designing the main passage 41 can be improved.

[0070] As described above, in the power conversion device 10 having the vertically arranged circuit board 20 and the cooling unit 40 having the cooling passage for cooling the heat-generating components 30 of the circuit board 20, it is possible to suppress variations in the temperature of the heat-generating components 30 after cooling and to realize a configuration capable of improving the degree of freedom in designing the cooling passage in the cooling unit 40.

[0071] Also, in the above-described configuration, the inlet portion 411 is provided at the upper part of the cooling unit 40. Thereby, the air AR1 is easily discharged to the outside of the cooling unit 40 through the inlet portion 411 located at the upper part of the cooling unit 40. Therefore, it is possible to realize the power conversion device 10 in which an air pool is less likely to occur in the cooling unit 40.

[0072] Furthermore, according to the above-described configuration, even when a posture change occurs such that the mounting target of the power conversion device 10 tilts, the generation of an air pool can be suppressed. For example, when the mounting target is a two-wheeled vehicle, by using a side stand or a center stand during parking, the vehicle body tilts in the left-right direction or the front-rear direction of the two-wheeled vehicle. According to the above-described configuration, even when such a posture change occurs, it is possible to suppress the formation of an air pool.

[0073] [Embodiment 2] (Schematic Configuration) FIG. 4 is a perspective view showing a schematic configuration of the power conversion device 11 according to Embodiment 2. FIG. 5 is an exploded view of the power conversion device 11 shown in FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. 4. FIG. 7 is a schematic diagram for explaining the folded portions 4511, 4512, 4513, 4514. In the power conversion device 11 according to Embodiment 2, a main passage 41 of the cooling unit 400 is formed for two systems of inverter circuits. In the following description of Embodiment 2, parts common to the battery state detection device 10 according to Embodiment 1 are denoted by the same reference numerals and detailed description will not be repeated.

[0074] As shown in FIGS. 4 to 7, the power conversion device 11 includes a first cover 51, a control board 25, a circuit board 200, a cooling unit 400, a second cover 52, input cables 531, 532, and a plurality of output cables 541, 542.

[0075] The control board 25 is located on one side of the circuit board 200. The control board 25 performs switching control on the first inverter circuit 201 and the second inverter circuit 202, which are two systems of inverter circuits on the circuit board 200. Note that the power for operating the control board 25 may be supplied from the circuit board 200 or from a power source (not shown).

[0076] The circuit board 200 includes a metal board such as aluminum. The thermal conductivity of the circuit board 200 is improved compared to the case where the circuit board 200 is made of resin. Therefore, the heat dissipation performance of the circuit board 200 is improved. Further, the circuit board 200 is a circuit for power conversion. On one surface 21 of the circuit board 200, a first inverter circuit 201, a second inverter circuit 202, and a connecting member 205 are formed.

[0077] On one surface 21 of the circuit board 200, a heat-generating component 301 including a switching element or the like that constitutes the first inverter circuit 201 is mounted. The circuit board 200 has an input terminal 231 and output terminals 241, 242, 243. The input terminal 231 and the output terminals 241, 242, 243 extend in the other direction RR in the depth direction of the power conversion device 11. The input terminal 231 is electrically connected to the input cable 531 in a state of passing through a through hole 431 that penetrates the cooling unit 400 in the depth direction. The output terminals 241, 242, 243 are electrically connected to a plurality of output cables 541 in a state of being inserted into a through hole 432 that penetrates the cooling unit 400 in the depth direction.

[0078] On one surface 21 of the circuit board 200, a heat-generating component 302 including a switching element or the like that constitutes the second inverter circuit 202 is mounted. The circuit board 200 has an input terminal 251 and output terminals 261, 262, 263. The input terminal 251 is electrically connected to the input cable 532 in a state of being inserted into a through hole 431 that penetrates the cooling unit 400 in the depth direction. The output terminals 261, 262, 263 are electrically connected to a plurality of output cables 542 in a state of being inserted into a through hole 433 that penetrates the cooling unit 400 in the depth direction.

[0079] The connecting member 205 supports the control board 25 with respect to the circuit board 200 in one direction FR in the depth direction of the power conversion device 11.

[0080] Further, the circuit board 200 has a recess 204 that is recessed upward with respect to the lower end portion 203 of the circuit board 200 at a position in the center of the width direction. The main passage 41 of the cooling unit 400 described later extends avoiding the recess 204 when viewed in the depth direction.

[0081] The first cover 51 is located in one direction FR in the depth direction of the power conversion device 11 with respect to the cooling unit 400. The first cover 51 covers the circuit board 200 and the control board 25.

[0082] The second cover 52 covers the connection portion between the input terminal 231 of the first inverter circuit 201 and the input cable 531, the connection portions between the output terminals 241, 242, 243 and the plurality of output cables 541, the connection portion between the input terminal 251 of the second inverter circuit 202 and the input cable 532, and the connection portions between the output terminals 261, 262, 263 and the plurality of output cables 542.

[0083] The main passage 41 of the cooling unit 400 is open to one side FR in the depth direction. The cooling unit 400 is connected to the other surface 22 of the circuit board 200 via a sealing material such as an O-ring (not shown). The main passage 41 of the cooling unit 400 is open to one side FR in the depth direction. Thereby, the coolant flowing in the cooling unit 400 directly contacts the other surface 22 of the circuit board 200 to perform cooling. The cooling unit 400 has the main passage 41 and the sub-passages 421, 422, 423, 424. In FIG. 6, the positions of the circuit board 200 and the heat-generating components 301, 302 when the power conversion device 11 is viewed in the depth direction are represented by a two-dot chain line.

[0084] The flow path areas of the sub-passages 421, 422, 423, 424 are each smaller than the flow path area of the main passage 41.

[0085] Thereby, the amount of the coolant flowing into or out of the sub-passages 421, 422, 423, 424 from the main passage 41 can be suppressed. Thereby, it can be suppressed that the flow of the coolant flowing through the sub-passages 421, 422, 423, 424 obstructs the flow of the coolant flowing through the main passage 41.

[0086] The main passage 41 has folding portions 4511, 4512, 4513, 4514, first portions 4521, 4522, 4523, 4524, and second portions 4531, 4532, 4533, 4534. The second portion 4531 is located below the first portion 4521. The second portion 4532 is located below the first portion 4522. The second portion 4533 is located below the first portion 4523. The second portion 4534 is located below the first portion 4524.

[0087] Also, the second portions 4531, 4532, 4533, 4534 each have bending portions 4531a, 4532a, 4533a, 4534a that extend in the width direction along the other surface 22 of the circuit board 200 and bend downward. Also, the folding portions 4512, 4513, 4514 have three or more bending portions.

[0088] As shown in FIG. 7, the sub-passage 421 bypasses the folding portion 4511 and connects the first portion 4521 and the bending portion 4531a of the second portion 4531 in the vertical direction. The sub-passage 422 bypasses the folding portion 4512 and connects the first portion 4522 and the bending portion 4532a of the second portion 4532 in the vertical direction. The sub-passage 423 bypasses the folding portion 4513 and connects the first portion 4523 and the bending portion 4533a of the second portion 4533 in the vertical direction. The sub-passage 424 bypasses the folding portion 4514 and connects the first portion 4524 and the bending portion 4534a of the second portion 4534 in the vertical direction.

[0089] Also, the sub-passages 422, 423, 424 connect the first portions 4522, 4523, 4524 and the bent portions 4532a, 4533a, 4534a of the second portions 4532, 4533, 4534. At the bent portions 4532a, 4533a, 4534a of the second portions 4532, 4533, 4534, the flow rate of the coolant becomes gentle. Therefore, at the bent portions 4532a, 4533a, 4534a of the second portions 4532, 4533, 4534, the dynamic pressure of the coolant is lower than that of the linearly extending portions in the second portions 4532, 4533, 4534. The sub-passages 422, 423, 424 connect the first portions 4522, 4523, 4524 and the bent portions 4532a, 4533a, 4534a where the dynamic pressure is low in the second portions 4532, 4533, 4534. Therefore, it is difficult for the coolant to flow from the first portions 4522, 4523, 4524 toward the bent portions 4532a, 4533a, 4534a of the second portions 4532, 4533, 4534 in the sub-passages 422, 423, 424. Thus, the amount of the coolant flowing in the sub-passages 422, 423, 424 can be suppressed, and the coolant can be smoothly flowed into the main passage 41. Further, when the flow of the coolant stops in the cooling portion 400, air can be vented upward through the sub-passages 421, 422, 423, 424 as indicated by the white arrows in FIG. 7.

[0090] [Other Embodiments] As described above, the embodiments of the present invention have been described. However, the above-described embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and implemented without departing from the gist thereof.

[0091] In each of the above embodiments, the power conversion devices 10, 11 are attached to an attachment target such as a moving body, for example. However, the power conversion device may be attached to other devices or structures, etc., or may be used alone without being attached to other devices or structures, etc.

[0092] In each of the above embodiments, the inlet portion 411 is provided above the cooling portions 40 and 400. However, the outlet portion may be provided above the cooling portion. Also, both the inlet portion and the outlet portion may be provided above the cooling portion, or may be provided below the cooling portion.

[0093] In each of the above embodiments, on the drawing, in the main passage 41, the first portions 452, 4521, 4522, 4523, 4524 and the second portions 453, 4531, 4532, 4533, 4534 extend in the width direction. However, the configuration of the main passage is not limited to this. For example, the first portion and the second portion may extend obliquely with respect to the width direction. Also, the bent portion may bend in a direction intersecting the direction in which the first portion and the second portion extend. Also, the positional relationship and the bending structure of the folded-back portion, the first portion, and the second portion are not limited to the above-described configuration. Also, the main passage may have a path through which the coolant flows in order based on the heat generation amount of the heat-generating component. For example, the main passage may have the path through which the coolant flows in descending order of the heat generation amount of the heat-generating component. The heat generation amount may be the maximum or the average.

[0094] In each of the above embodiments, the sub-passages 421, 422, 423, 424 extend in the vertical direction. However, the sub-passage may extend in the vertical direction and also in the width direction. Also, the position of the sub-passage is not limited to the above-described configuration.

[0095] In each of the above embodiments, although not particularly described, the straight portions of the first portion and the second portion may have a uniform flow path area, or the flow path area may change in the middle of the path. Also, the first portion and the second portion may have a widened portion.

[0096] In each of the above embodiments, the inlet portion 411 is connected to an external pump or the like that sends out the coolant. However, instead of the inlet portion, the outlet portion may be connected to the pump.

[0097] In each of the above embodiments, the power conversion devices 10 and 11 are located on one side VLF in the vehicle width direction with respect to the battery B1. However, the power conversion device may be located on the other side in the vehicle width direction with respect to the battery, or may be located in front of the battery in the longitudinal direction of the vehicle. Also, the method of attaching the power conversion device to the battery is not particularly limited. The power conversion device may be attached to the battery by a member other than a bracket. Further, the power conversion device does not have to be arranged along the side wall of the battery. Also, the power conversion device may be attached to another member other than the battery.

[0098] In Embodiment 1, although not particularly described, the cooling unit may be a direct water cooling method or a cooling method other than the direct water cooling method.

[0099] In Embodiment 2, the main passage 41 of the cooling unit 400 extends avoiding the recess 204 when viewed in the depth direction. However, the main passage of the cooling unit may extend passing through the recess when viewed in the depth direction. Also, the circuit board does not have to have a recess.

[0100] In Embodiment 2, the output terminals 241, 242, and 243 are electrically connected to the plurality of output cables 541 in a state of being inserted into the through holes 432 of the cooling unit 400. Also, the output terminals 261, 262, and 263 are electrically connected to the plurality of output cables 542 in a state of being inserted into the through holes 433 penetrating the cooling unit 400 in the depth direction. The input terminal 251 is electrically connected to the input cable 532 in a state of being inserted into the through hole 431 of the cooling unit 400. However, the output terminals may be connected to the output cables without passing through the cooling unit. Also, the input terminal may be connected to the input cable without passing through the cooling unit.

Explanation of Reference Numerals

[0101] 10, 11 Power conversion device 20 Circuit board 21 One surface 22 The other surface 25 Control board 30 Heat-generating component 40 Cooling section 41 Main passage 42 Sub passage 51 First cover 52 Second cover 200 Circuit board 201 First inverter circuit 202 Second inverter circuit 203 Lower end part 204 Recess 205 Connecting member 231 Input terminal 241, 242, 243 Output terminals 251 Input terminal 261, 262, 263 Output terminals 301, 302 Heat-generating components 400 Cooling section 411 Inlet part 412 Outlet part 421, 422, 423, 424 Sub passages 431, 432, 433 Through holes 451 Folding part 451a, 451b Bending parts 452 First part 453 Second part 531, 532 Input cables 541, 542 Output cables 4511, 4512, 4513, 4514 Folding parts 4521, 4522, 4523, 4524 First parts 4531, 4532, 4533, 4534 Second parts 4531a, 4532a, 4533a, 4534a Bending parts AR1 Air

Claims

1. A power conversion device having a circuit board with one surface arranged along the vertical direction, a heat-generating component mounted on one surface of the circuit board, and a cooling component arranged on the other surface of the circuit board, wherein the cooling component has, inside thereof, an inlet portion to which a coolant is supplied and an outlet portion for discharging the coolant, a main passage that extends along the other surface of the circuit board and has a path connecting the inlet portion and the outlet portion, a sub-passage that bypasses and connects a part of the main passage, and has, the main passage has at least one folding portion located between the inlet portion and the outlet portion, a first portion located closer to the inlet portion than the folding portion, a second portion located closer to the outlet portion than the folding portion and located below the first portion, and has, the sub-passage bypasses at least the folding portion of the main passage and connects the first portion and the second portion in the vertical direction, a power conversion device.

2. In the power conversion device according to Claim 1, the flow passage area of the sub-passage is smaller than the flow passage area of the main passage, a power conversion device.

3. In the power conversion device according to Claim 1 or Claim 2, in the main passage, the second portion has a bent portion that extends along the other surface of the circuit board and bends, the sub-passage connects the first portion and the bent portion of the second portion, a power conversion device.

4. In the power conversion device according to any one of Claims 1 to 3, at least one of the inlet portion or the outlet portion is located at the upper part of the cooling component, a power conversion device.

5. In the power conversion device according to any one of Claims 1 to 4, the circuit board includes a metal substrate, a power conversion device.

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