Cooling device and semiconductor device

Abstract

A cooling device according to one embodiment of the present disclosure is a cooling device for cooling a heat generating body, and is provided with a case, a first flow path, and a second flow path. The box body is provided with an inflow port and an outflow port of a refrigerant, and comprises a first area in contact with the first heating body and a second area in contact with the second heating body. The first flow path is a flow path connecting the inlet and the outlet, and overlaps the first region and the second region in a plan view of the housing. The second flow path merges with the first flow path at a position downstream of the first region and upstream of the second region. In addition, the second flow path has a guide portion that guides the refrigerant flowing through the second flow path to the first flow path.

Description

Technical Field

[0001] The present disclosure relates to a cooling device and a semiconductor device. Background Art

[0002] Conventionally, there is known a semiconductor device including a semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor).

[0003] Semiconductor elements such as IGBTs generate a large amount of heat when in operation. Therefore, a technique for cooling semiconductor elements using a refrigerant-type cooling device has been proposed (for example, see Patent Document 1). The refrigerant-type cooling device has a flow path inside, and the refrigerant (for example, cooling water) flowing in the flow path moves the heat generated by the semiconductor element to the outside, thereby cooling the semiconductor element.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-52060 Summary of the invention

[0007] However, when a plurality of semiconductor elements are cooled using the refrigerant-type cooling device, there is a possibility that a difference in cooling temperature may occur between the semiconductor element provided on the upstream side and the semiconductor element provided on the downstream side.

[0008] The present disclosure provides a technology capable of suppressing variations in cooling temperature among a plurality of cooling targets.

[0009] A cooling device according to one embodiment of the present disclosure is a cooling device for cooling a heating element, and comprises a housing, a first flow path, and a second flow path. The housing has an inlet and an outlet for a refrigerant, and includes a first region connected to the first heating element and a second region connected to the second heating element. The first flow path is a flow path connecting the inlet and the outlet, and overlaps with the first region and the second region when the housing is viewed from above. The second flow path merges with the first flow path at a position downstream of the first region and upstream of the second region. In addition, the second flow path has a guide portion for guiding the refrigerant flowing in the second flow path to the first flow path.

[0010] According to the present disclosure, it is possible to suppress variations in cooling temperature among a plurality of cooling targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram showing an example of a circuit configuration of the power conversion device according to the first embodiment.

[0012] Figure 2It is a schematic side view of the cooling device according to the first embodiment.

[0013] Figure 3 It is a schematic top view of the substrate of the first embodiment.

[0014] Figure 4 yes Figure 2 A schematic cross-sectional view taken along line IV-IV is shown.

[0015] Figure 5 yes Figure 4 A schematic cross-sectional view taken along line VV is shown.

[0016] Figure 6 yes Figure 4 A schematic cross-sectional view taken along line VI-VI is shown.

[0017] Figure 7 yes Figure 4 A schematic cross-sectional view taken along line VII-VII is shown.

[0018] Figure 8 It is a schematic enlarged view of the second flow path and the third flow path in the first embodiment.

[0019] Fig. 9 It is a schematic plan cross-sectional view showing the internal structure of the cooling device according to the second embodiment.

[0020] Fig.10 yes Fig. 9 A schematic cross-sectional view taken along line XX is shown.

[0021] Fig.11 yes Fig. 9 A schematic cross-sectional view taken along line XI-XI is shown.

[0022] Fig.12 yes Fig. 9 A schematic cross-sectional view taken along line XII-XII is shown.

[0023] Fig.13 yes Fig. 9 A schematic cross-sectional view taken along line XIII-XIII is shown.

[0024] Fig.14 It is a schematic enlarged view of the second flow path and the third flow path in the second embodiment.

[0025] Fig.15 It is a graph showing the relationship between the flow rate of the refrigerant and the thermal resistance of the switching element.

[0026] Fig.16 : is a graph showing conditions and the results of calculating the temperature of the switching element under the conditions. DETAILED DESCRIPTION

[0027] Hereinafter, a method for implementing the cooling device and semiconductor device of the present disclosure (hereinafter referred to as an "implementation method") will be described in detail with reference to the accompanying drawings. In the implementation method shown below, an example of a case where a semiconductor device having a cooling device of the present disclosure is applied to a power conversion device is described, but the present disclosure is not limited to this implementation method. In addition, each implementation method can be appropriately combined within the scope of the processing content not contradictory. In addition, in each of the following implementation methods, the same reference numerals are marked on the same parts, and repeated descriptions are omitted.

[0028] In the embodiments shown below, expressions such as "constant", "orthogonal", "perpendicular" or "parallel" are sometimes used, but these expressions do not need to be strictly "constant", "orthogonal", "perpendicular" or "parallel". That is, the above expressions allow for deviations in manufacturing accuracy, setting accuracy, etc.

[0029] Conventionally, there are known semiconductor devices including semiconductor elements such as insulated gate bipolar transistors (IGBTs). Semiconductor elements generate a large amount of heat during operation. Therefore, there are proposed semiconductor devices including a cooling device for cooling the semiconductor elements.

[0030] Here, for example, in a power conversion device which is a type of semiconductor device, a plurality of switching elements (an example of semiconductor elements) constituting the U phase, the V phase, and the W phase are sometimes mounted on a refrigerant-type cooling device. However, when this structure is adopted, a deviation in cooling temperature may occur between the switching element located on the upstream side of the flow direction of the refrigerant and the switching element located on the downstream side. This is because the refrigerant heated by the switching element on the upstream side is used to cool the switching element on the downstream side. In this way, when a deviation in cooling temperature occurs among a plurality of switching elements, for example, the switching element on the downstream side which is insufficiently cooled may be more prone to failure than the switching element on the upstream side. In addition, considering the rise in the temperature of the refrigerant, it is also considered to pre-set the temperature of the refrigerant supplied to the cooling device to be lower, but this may lead to an increase in operating costs.

[0031] Therefore, a technology capable of suppressing the variation in cooling temperature among a plurality of cooling objects is desired.

[0032] <1. Power conversion device 1>

[0033] Figure 1 It is a diagram showing an example of the circuit configuration of the power conversion device 1 according to the first embodiment. Figure 1The power conversion device 1 shown converts DC power into AC power, and outputs the converted AC power to the motor 2. For example, the power conversion device 1 is connected to a converter circuit (not shown) that converts AC power supplied from an AC power source (not shown) into DC power, converts the DC power output from the converter circuit into AC power, and outputs the converted AC power to the motor 2. In addition, the power conversion device 1 may be directly connected to a DC power source (not shown) without passing through the converter circuit.

[0034] like Figure 1 As shown, the power conversion device 1 includes two switching elements 3u, two switching elements 3v, and two switching elements 3w. In addition, the power conversion device 1 includes two diodes 4u, two diodes 4v, two diodes 4w, and a gate driver 5. In addition, the power conversion device 1 may also be provided with a filter (not shown) composed of a coil and a capacitor on the U phase, the V phase, and the W phase. In addition, the power conversion device 1 may also be a structure without the above-mentioned filter.

[0035] The two switching elements 3u form a half-bridge circuit of the U phase, the two switching elements 3v form a half-bridge circuit of the V phase, and the two switching elements 3w form a half-bridge circuit of the W phase. The two switching elements 3u are connected in series. Similarly, the two switching elements 3v are connected in series, and the two switching elements 3w are also connected in series.

[0036] The switch elements 3u, 3v, and 3w are, for example, insulated gate bipolar transistors (IGBTs) or power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The switch elements 3u, 3v, and 3w are, for example, switch elements formed of silicon-based materials or switch elements formed of wide bandgap semiconductors. Wide bandgap semiconductors are, for example, silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), or diamond.

[0037] Two diodes 4u are connected in reverse parallel to the corresponding switching elements 3u. Similarly, two diodes 4v are connected in reverse parallel to the corresponding switching elements 3v, and two diodes 4w are connected in reverse parallel to the corresponding switching elements 3w. The diodes 4u, 4v, and 4w are reflux diodes for protecting the switching elements 3u, 3v, and 3w.

[0038] Hereinafter, when the switching elements 3u, 3v, and 3w are shown without being individually distinguished, they may be described as the switching element 3. Moreover, when the diodes 4u, 4v, and 4w are shown without being individually distinguished, they may be described as the diode 4.

[0039] The gate driver 5 amplifies a gate signal outputted from a control unit (not shown) and outputs the amplified gate signal to the plurality of switching elements 3 .

[0040] <2. Cooling device 100 >

[0041] Next, an example of the configuration of the cooling device 100 included in the power conversion device 1 will be described. Figure 2 It is a schematic side view of the cooling device 100 according to the first embodiment.

[0042] In the drawings referred to below, in order to facilitate understanding of the description, an orthogonal coordinate system is sometimes shown which defines an X-axis direction, a Y-axis direction, and a Z-axis direction that are orthogonal to each other and has the positive Z-axis direction as the vertical direction.

[0043] In addition, in the drawings referred to below, in order to make the description easy to understand, a diagram is shown in which only a plurality of switching elements 3 are arranged on the substrate 20. In addition, in fact, in addition to the plurality of switching elements 3, for example, a plurality of diodes 4 are arranged on the substrate 20. The switching elements 3 and the diodes 4 can be mounted on the substrate 20 via an insulating substrate. In addition, a molded resin or the like that seals the switching elements 3 and the diodes 4 may also be arranged on the substrate 20.

[0044] The cooling device 100 is a refrigerant type cooling device for cooling the switching element 3 as a heating element. The switching element 3u is also an example of a first semiconductor element. In addition, the switching element 3u is also an example of a first heating element. The switching element 3v is an example of a second semiconductor element and also an example of a second heating element. The switching element 3w is an example of a third semiconductor element and also an example of a third heating element.

[0045] The refrigerant is, for example, a liquid such as cooling water, but the present invention is not limited thereto and the refrigerant may be a gas.

[0046] like Figure 2 As shown, the cooling device 100 of the first embodiment includes a housing 10. The housing 10 includes a substrate 20 and a main body 30. The substrate 20 and the main body 30 are made of a metal material such as aluminum or an aluminum alloy.

[0047] The substrate 20 is a substantially plate-shaped member. Figure 3 2 is a schematic top view of the substrate 20 of the first embodiment. Figure 3 As shown, the substrate 20 has a first surface 201. The first surface 201 is a flat surface. A plurality of switching elements 3u, 3v, 3w are arranged on the first surface 201.

[0048] The switch elements 3u, 3v, and 3w are arranged in sequence along the flow direction of the refrigerant (here, the positive direction of the X axis). The two switch elements 3u are arranged in a direction perpendicular to the flow direction of the refrigerant (here, the Y axis direction). The two switch elements 3v are arranged in a direction perpendicular to the flow direction of the refrigerant, and the two switch elements 3w are arranged in a direction perpendicular to the flow direction of the refrigerant.

[0049] The substrate 20 includes a first region 21, a second region 22, and a third region 23 on the first surface 201. The first region 21, the second region 22, and the third region 23 are arranged at intervals from each other.

[0050] The first region 21 is a region in contact with the switching element 3u. Similarly, the second region 22 is a region in contact with the switching element 3v, and the third region 23 is a region in contact with the switching element 3w.

[0051] As an example, the first region 21 may be a rectangular region that is in contact with the outer edges of the two switch elements 3u when viewed from above. Similarly, the second region 22 may be a rectangular region that is in contact with the outer edges of the switch element 3v when viewed from above, and the third region 23 may be a rectangular region that is in contact with the outer edges of the switch element 3w when viewed from above.

[0052] In addition, the sizes of the first area 21, the second area 22, and the third area 23 are not limited to the examples shown in the figure. For example, the first area 21, the second area 22, and the third area 23 may be larger than 100 mm in a range where they do not overlap with each other. Figure 3 Example shown.

[0053] A plurality of fins 25 are provided on the second surface 202 of the substrate 20 located on the opposite side of the first surface 201 (see Figure 5 The plurality of fins 25 are, for example, rod-shaped. In addition, the plurality of fins 25 may also be plate-shaped.

[0054] The main body 30 is a substantially container-shaped member opened at the top. The main body 30 is joined to the substrate 20 by laser welding or the like. By joining the substrate 20 and the main body 30, a first flow path 31, a second flow path 32, and a third flow path 33 described later are formed inside the housing 10.

[0055] Specifically, the main body 30 has a groove on the inner wall surface that constitutes at least a portion of the first flow path 31, the second flow path 32 and the third flow path 33, and the first flow path 31, the second flow path 32 and the third flow path 33 are formed by blocking the open portion of the above-mentioned groove with the second surface 202 of the substrate 20.

[0056] In addition, as a method for joining the substrate 20 and the main body 30, in addition to laser welding, for example, ultrasonic joining, friction stir joining, and the like can also be used. In addition, the substrate 20 and the main body 30 can also be fixed by screws. For example, a plurality of threaded holes can be provided around the substrate 20 and the main body 30, and the substrate 20 and the main body 30 can be fastened by inserting screws through these threaded holes, thereby joining the substrate 20 and the main body 30. In addition, at this time, in order to improve the airtightness of the interior of the box 10, an annular sealing member (such as an O-ring, etc.) can also be sandwiched between the substrate 20 and the main body 30.

[0057] Figure 4 yes Figure 2 The schematic cross-sectional view taken along the line IV-IV is shown. Figure 4 In the figure, the plurality of fins 25 are omitted and shown.

[0058] like Figure 4 As shown, the cooling device 100 includes a first flow path 31 , two second flow paths 32 , and two third flow paths 33 inside the housing 10 .

[0059] The first flow path 31 is a flow path connecting the inlet 301 and the outlet 302 provided in the housing 10. The inlet 301 is opened on the side surface of the housing 10 on the negative direction of the X axis, and the outlet 302 is opened on the side surface of the housing 10 on the positive direction of the X axis. The first flow path 31 extends linearly along the X axis direction, and allows the refrigerant flowing in from the inlet 301 to flow along the positive direction of the X axis and be guided to the outlet 302.

[0060] In a plan view, the first flow path 31 overlaps the first region 21 , the second region 22 , and the third region 23 . That is, the first flow path 31 is located directly below the first region 21 , the second region 22 , and the third region 23 .

[0061] The two second flow paths 32 are branched from the first flow path 31 at a position downstream of the inlet 301 and upstream of the first region 21. Specifically, the two second flow paths 32 are branched from the first flow path 31 in a manner of bypassing the first region 21 in a direction (Y-axis direction) orthogonal to the flow direction (X-axis direction) of the refrigerant in the first flow path 31. One of the two second flow paths 32 is branched from the first flow path 31 in a manner of bypassing the first region 21 in the positive direction of the Y-axis, and the other is branched from the first flow path 31 in a manner of bypassing the first region 21 in the negative direction of the Y-axis. Moreover, the two second flow paths 32 merge with the first flow path 31 at a position downstream of the first region 21 and upstream of the second region 22.

[0062] In this way, the two second flow paths 32 are arranged at positions that do not overlap with the first region 21 , the second region 22 , and the third region 23 in a plan view.

[0063] The main body 30 includes a first flow path forming portion 311 and a second flow path forming portion 312. The first flow path forming portion 311 is a partition wall that separates the first flow path 31 from the second flow path 32. The first flow path forming portion 311 has a gap with the inner wall 303 of the main body 30. The gap corresponds to a detour portion 321 of the second flow path 32 that bypasses the first region 21 (see Figure 8 ). The first region 21 is arranged between the two first flow path forming portions 311. The second flow path forming portion 312 is a partition wall arranged downstream of the first flow path forming portion 311. The second flow path forming portion 312 has a gap with the first flow path forming portion 311. The gap corresponds to the confluence portion 322 (see Figure 8 ).

[0064] The two third flow paths 33 branch from the second flow path 32 and merge with the first flow path 31. Specifically, the third flow path 33 branches from the second flow path 32 at a position upstream of the second region 22, extends in a manner bypassing the second region 22, and merges with the first flow path 31 at a position downstream of the second region 22 and upstream of the third region 23. In this way, the two third flow paths 33 are arranged at a position that does not overlap with the first region 21, the second region 22, and the third region 23 in a plan view.

[0065] The second flow path forming portion 312 has a gap between itself and the inner wall 303 of the main body 30. This gap corresponds to the detour portion 331 of the third flow path 33 that bypasses the second region 22 (see Figure 8 ). The second region 22 is arranged between the two second flow path forming portions 312. In addition, the main body 30 includes a third flow path forming portion 313. The third flow path forming portion 313 is a partition wall disposed at a position downstream of the second flow path forming portion 312, and has a gap between the third flow path forming portion 312 and the second flow path forming portion 312. The gap corresponds to a confluence portion 332 (see Figure 8 ).

[0066] Figure 5 yes Figure 4 A schematic cross-sectional view taken along line VV is shown. Figure 6 yes Figure 4 A schematic cross-sectional view taken along line VI-VI is shown. Figure 7 yes Figure 4 A schematic cross-sectional view taken along line VII-VII is shown.

[0067] like Figure 5 to Figure 7As shown, the first flow path 31 is located directly below the switching elements 3u to 3w as the heat generating body. The heat generated by the switching elements 3u to 3w is moved to the outside of the cooling device 100 by the refrigerant flowing in the first flow path 31. Thus, the switching elements 3u to 3w are cooled. The plurality of fins 25 are located in the first flow path 31. Thus, the cooling efficiency of the first flow path 31 on the switching elements 3u to 3w can be improved.

[0068] On the other hand, Figure 5 As shown in FIG. 1 , the second flow path 32 is disposed at a position offset to the side from directly below the switching element 3u. Therefore, compared with the refrigerant flowing in the first flow path 31, the refrigerant flowing in the second flow path 32 is less susceptible to the heat generated by the switching element 3u.

[0069] The refrigerant that has passed directly below the first area 21 in the first flow path 31 will pass directly below the second area 22, but before passing directly below the second area 22, it will merge with the refrigerant flowing in from the second flow path 32, which is the refrigerant with a lower temperature than the refrigerant that has passed directly below the first area 21.

[0070] Thus, the cooling device 100 can cool the switching element 3v using a coolant having a lower temperature than when the second flow path 32 is not provided. In other words, the temperature rise of the coolant caused by the switching element 3u can be suppressed. Therefore, the cooling device 100 can suppress the occurrence of a deviation in cooling temperature between the switching element 3u and the switching element 3v arranged downstream thereof.

[0071] like Figure 6 As shown in FIG. 1 , the third flow path 33 is disposed at a position offset to the side from directly below the switching element 3 v. Therefore, the refrigerant flowing in the third flow path 33 is less susceptible to the heat generated by the switching element 3 v than the refrigerant flowing in the first flow path 31 .

[0072] The refrigerant that has passed through the second area 22 in the first flow path 31 will pass through the third area 23, but before passing directly below the third area 23, it merges with the refrigerant flowing in from the third flow path 33, i.e., the refrigerant having a lower temperature than the refrigerant that has passed directly below the second area 22.

[0073] Thus, the cooling device 100 can cool the switching element 3w using a coolant having a lower temperature than when the third flow path 33 is not provided. In other words, the temperature rise of the coolant caused by the switching elements 3u and 3v can be suppressed. Therefore, the cooling device 100 can suppress the occurrence of a deviation in cooling temperature between the switching element 3v and the switching element 3w arranged downstream thereof.

[0074] As described above, according to the cooling device 100 of the first embodiment, the second flow path 32 and the third flow path 33 are provided in addition to the first flow path 31 , thereby suppressing the occurrence of variations in cooling temperature among the switching elements 3u , 3v , and 3w .

[0075] In addition, the flow rate of the refrigerant flowing in the first flow path 31 increases as the refrigerant flows downstream in the flow direction of the refrigerant due to the refrigerant flowing in from the second flow path 32 and the refrigerant flowing in from the third flow path 33. Since the thermal resistance of the switching element 3 decreases as the flow rate of the refrigerant increases, the deviation in cooling temperature between the switching element 3u, the switching element 3v, and the switching element 3w can be suppressed.

[0076] like Figure 5 as well as Figure 6 As shown, the flow path cross-sectional area at the branch portion (detour portion 321 described later) of the second flow path 32 branching from the first flow path 31 is smaller than that of the first flow path 31, and is larger than that of the third flow path 33 branching from the second flow path 32 (detour portion 331 described later). As a result, the flow velocity of the refrigerant in the third flow path 33 is faster than that of the refrigerant in the second flow path 32, so that the cooling temperatures of the switching elements 3u, 3v, and 3w can be further uniformed.

[0077] Next, refer to Figure 8 A specific configuration example of the second flow path 32 and the third flow path 33 will be described. Figure 8 It is a schematic enlarged view of the second flow path 32 and the third flow path 33 in the first embodiment.

[0078] like Figure 8 As shown, the second flow path 32 includes a first guide portion 51 that guides the refrigerant flowing in the second flow path 32 to the first flow path 31 .

[0079] Specifically, the second flow path 32 has a detour portion 321 formed between the first flow path forming portion 311 and the inner wall 303 of the housing 10 and a confluence portion 322 located downstream of the detour portion 321. Furthermore, the second flow path forming portion 312 has a portion located closer to the inner wall 303 of the housing 10 than the imaginary line L1 formed by virtually extending the first flow path forming portion 311 along the flow direction (X-axis positive direction) of the refrigerant in the detour portion 321. In this way, the second flow path 32 has a portion that collides with the flow of the refrigerant in the detour portion 321 as the first guide portion 51.

[0080] The second flow path 32 includes the first guide portion 51, so that the refrigerant flowing in the second flow path 32 can efficiently flow into the first flow path 31. That is, for example, even if the second flow path 32 does not include the first guide portion 51, although there is refrigerant flowing into the first flow path 31 through the junction portion 322, it is difficult to obtain a flow rate sufficient to reduce the temperature of the refrigerant flowing in the first flow path 31. In contrast, the second flow path 32 of the first embodiment includes the first guide portion 51, so that the refrigerant flowing in the detour portion 321 can be actively directed toward the junction portion 322, and thus the refrigerant can flow from the second flow path 32 into the first flow path 31 at a faster flow rate. Therefore, the second flow path 32 of the first embodiment can efficiently reduce the temperature of the refrigerant flowing in the first flow path 31.

[0081] The confluence portion 322 of the second flow path 32 extends obliquely from the detour portion 321 toward the first flow path 31. Specifically, the first flow path forming portion 311 has a first wall surface 311a that forms the confluence portion 322 with the second flow path forming portion 312. In addition, the second flow path forming portion 312 has a second wall surface 312a that forms the confluence portion 322 with the first flow path forming portion 311. Moreover, these first wall surfaces 311a and the second wall surfaces 312a extend obliquely toward the first flow path 31. By adopting this structure, the refrigerant can flow from the second flow path 32 into the first flow path 31 at a faster flow rate. Therefore, according to the second flow path 32 of the first embodiment, the temperature of the refrigerant flowing in the first flow path 31 can be efficiently reduced.

[0082] The third flow passage 33 includes a second guide portion 52 that guides the refrigerant flowing in the third flow passage 33 toward the first flow passage 31 .

[0083] Specifically, the third flow path 33 has a detour portion 331 formed between the second flow path forming portion 312 and the inner wall 303 of the housing 10, and a confluence portion 332 located downstream of the detour portion 331. In addition, the third flow path forming portion 313 has a portion located closer to the inner wall 303 of the housing 10 than the imaginary line L2 formed by virtually extending the second flow path forming portion 312 along the flow direction (X-axis positive direction) of the refrigerant in the detour portion 331. In this way, the third flow path 33 has a portion that collides with the flow of the refrigerant in the detour portion 331 as the second guide portion 52.

[0084] The third flow passage 33 can efficiently flow the refrigerant flowing in the third flow passage 33 into the first flow passage 31 by including the second guide portion 52. Thus, the third flow passage 33 of the first embodiment can efficiently reduce the temperature of the refrigerant flowing in the first flow passage 31.

[0085] In addition, the confluence portion 332 of the third flow path 33 extends obliquely from the detour portion 331 toward the first flow path 31. Specifically, the second flow path forming portion 312 has a third wall 312b that forms the confluence portion 332 between the second flow path forming portion 313. In addition, the third flow path forming portion 313 has a fourth wall 313a that forms the confluence portion 332 between the second flow path forming portion 312. Moreover, these third wall 312b and fourth wall 313a extend obliquely toward the first flow path 31. By adopting this structure, the refrigerant can flow from the third flow path 33 into the first flow path 31 at a faster flow rate. Thus, the second flow path 32 of the first embodiment can efficiently reduce the temperature of the refrigerant flowing in the first flow path 31.

[0086] (Second embodiment)

[0087] Next, the structure of the cooling device 100A according to the second embodiment will be described. Fig. 9 100A is a schematic plan cross-sectional view showing the internal structure of a cooling device 100A according to the second embodiment. Fig. 9 The top cross-sectional view shown is equivalent to Fig.10 A cross-sectional view taken along line IX-IX is shown. Fig.10 yes Fig. 9 A schematic cross-sectional view taken along line XX is shown. Fig.11 yes Fig. 9 A schematic cross-sectional view taken along line XI-XI is shown. Fig.12 yes Fig. 9 A schematic cross-sectional view taken along line XII-XII is shown. Fig.13 yes Fig. 9 A schematic cross-sectional view taken along line XIII-XIII is shown.

[0088] like Fig. 9 as well as Fig.10 As shown, the cooling device 100A provided in the power conversion device 1A of the second embodiment includes a first flow path 31A, a second flow path 32A, and a third flow path 33A inside the housing 10A. The first flow path 31A is a flow path connecting the inlet 301A and the outlet 302A of the housing 10A, and when viewed from above, the first flow path 31A overlaps the first area 21, the second area 22, and the third area 23. A plurality of fins 25 provided on the second surface 202 of the substrate 20 are arranged in the first flow path 31A.

[0089] In the second embodiment, the second flow path 32A and the third flow path 33A are located directly below the first flow path 31A. That is, the second flow path 32A is arranged at a position overlapping the first region 21 in plan view, and the third flow path 33A is arranged at a position overlapping the second region 22 in plan view.

[0090] The housing 10A includes a substrate 20 and a main body 30A. In addition, the main body 30A includes a first flow path forming portion 311A, a second flow path forming portion 312A, and a third flow path forming portion 313A inside. The first flow path forming portion 311A, the second flow path forming portion 312A, and the third flow path forming portion 313A are arranged in sequence along the flow direction (X-axis direction) of the refrigerant. In addition, the first flow path forming portion 311A, the second flow path forming portion 312A, and the third flow path forming portion 313A are arranged at intervals from each other.

[0091] The first flow path forming portion 311A ​​is a partition wall that separates the first flow path 31A from the second flow path 32A (see Fig.11 The second flow path forming portion 312A is a partition wall that separates the first flow path 31A from the third flow path 33A (see Fig.12 ).

[0092] The second flow path 32A branches from the first flow path 31A at a position downstream of the inlet 301A and upstream of the first region 21. Specifically, the second flow path 32A branches from the first flow path 31A in a manner that bypasses the first region 21 in a direction (Z-axis direction) orthogonal to the flow direction (X-axis direction) of the refrigerant in the first flow path 31A. Furthermore, the second flow path 32A merges with the first flow path 31A at a position downstream of the first region 21 and upstream of the second region 22.

[0093] The gap between the inner wall 303A of the main body 30A and the first flow path forming portion 311A ​​corresponds to the detour portion 321A of the second flow path 32A (see Fig.14 ). In addition, the gap between the first flow path forming portion 311A ​​and the second flow path forming portion 312A corresponds to a confluence portion 322A where the second flow path 32A merges with the first flow path 31A (see Fig.14 ).

[0094] The third flow path 33A branches from the second flow path 32A and merges with the first flow path 31A. Specifically, the third flow path 33A branches from the second flow path 32A upstream of the second region 22 and merges with the first flow path 31A downstream of the second region 22 and upstream of the third region 23 .

[0095] The gap between the inner wall 303A of the main body 30A and the second flow path forming portion 312A corresponds to the detour portion 331A of the third flow path 33A (see Fig.14 ). In addition, the gap between the second flow path forming portion 312A and the third flow path forming portion 313A corresponds to the confluence portion 332A where the third flow path 33A merges with the first flow path 31A (see Fig.14 ).

[0096] like Figure 11 to Figure 13 As shown, the first flow path 31A is located directly below the switching elements 3u to 3w as the heat generating body. The heat generated by the switching elements 3u to 3w is moved to the outside of the cooling device 100A by the refrigerant flowing in the first flow path 31A. As a result, the switching elements 3u to 3w are cooled. The plurality of fins 25 are located in the first flow path 31A, thereby enabling efficient cooling of the switching elements 3u to 3w.

[0097] On the other hand, Fig.11 As shown, the second flow path 32A is arranged at a position farther from the switching element 3u than the first flow path 31A. Therefore, the refrigerant flowing in the second flow path 32A is less susceptible to the temperature rise caused by the heat generated by the switching element 3u than the refrigerant flowing in the first flow path 31A.

[0098] After passing directly below the first area 21 in the first flow path 31A, the refrigerant will pass directly below the second area 22, but before passing directly below the second area 22, it will merge with the refrigerant flowing in from the second flow path 32A, which is the refrigerant with a lower temperature than the refrigerant passing directly below the second area 22.

[0099] Thus, the cooling device 100A can cool the switching element 3v using a coolant at a lower temperature than when the second flow path 32A is not provided. In other words, the temperature rise of the coolant caused by the switching element 3u can be suppressed. Therefore, the cooling device 100A can suppress the occurrence of a deviation in cooling temperature between the switching element 3u and the switching element 3v arranged downstream thereof.

[0100] like Fig.12 As shown, the third flow passage 33A is arranged at a position farther from the switching element 3v than the first flow passage 31A. Therefore, the refrigerant flowing in the third flow passage 33A is less susceptible to the temperature rise caused by the heat generated by the switching element 3v than the refrigerant flowing in the first flow passage 31A.

[0101] The refrigerant that has passed through the second region 22 in the first flow path 31A passes through the third region 23, but before passing through the third region 23, it merges with the refrigerant flowing in from the third flow path 33A, i.e., the refrigerant with less temperature rise caused by the switching element 3u and the switching element 3v, thereby reducing its temperature.

[0102] Thus, the cooling device 100 can cool the switching element 3w using a coolant having a lower temperature than when the third flow path 33A is not provided. In other words, the temperature rise of the refrigerant caused by the switching elements 3u and 3v can be suppressed. Therefore, the cooling device 100A can suppress the occurrence of a deviation in cooling temperature between the switching element 3v and the switching element 3w arranged downstream thereof.

[0103] As described above, according to the cooling device 100A of the second embodiment, by providing the second flow path 32A and the third flow path 33A, it is possible to suppress the occurrence of variations in cooling temperature among the switching element 3u, the switching element 3v, and the switching element 3w.

[0104] like Fig.11 as well as Fig.12 As shown, the flow path cross-sectional area at the branch portion (detour portion 321A described later) of the second flow path 32A branching from the first flow path 31A is smaller than that of the first flow path 31A, and is larger than the flow path cross-sectional area at the branch portion (detour portion 331A described later) of the third flow path 33A branching from the second flow path 32A. As a result, the flow velocity of the refrigerant in the third flow path 33A is faster than that of the refrigerant in the second flow path 32A, so that the cooling temperatures of the switching elements 3u, 3v, and 3w can be further uniformed.

[0105] The first flow path forming portion 311A ​​and the second flow path forming portion 312A have, for example, a gate-shaped shape (see Fig.11 as well as Fig.12 ). Thus, by forming the first flow path forming portion 311A ​​and the second flow path forming portion 312A into a gate shape, the positioning of the second flow path 32A and the third flow path 33 becomes easier than, for example, the case where the first flow path forming portion 311A ​​and the second flow path forming portion 312A are formed into a plate shape. Thus, for example, the height of the second flow path 32A and the third flow path 33 can be suppressed from varying in each product. In addition, for example, the ease of installation of the second flow path 32A and the third flow path 33 can be improved compared to, for example, the case where the first flow path forming portion 311A ​​and the second flow path forming portion 312A are formed into a plate shape.

[0106] Next, refer to Fig.14 A specific configuration example of the second flow path 32A and the third flow path 33A will be described. Fig.14 It is a schematic enlarged view of the second flow path 32A and the third flow path 33A according to the second embodiment.

[0107] like Fig.14 As shown, the second flow path 32A includes a first guide portion 51A that guides the refrigerant flowing in the second flow path 32A to the first flow path 31A.

[0108] Specifically, the second flow path 32A has a detour portion 321A formed between the first flow path forming portion 311A ​​and the inner wall 303A of the housing 10A, and a confluence portion 322A located downstream of the detour portion 321A. In addition, the second flow path forming portion 312A has a portion located closer to the inner wall 303A side of the housing 10A than the imaginary line L3 formed by virtually extending the first flow path forming portion 311A ​​along the flow direction of the refrigerant in the detour portion 321A (X-axis positive direction). In this way, the second flow path 32A has a portion of the detour portion 321A that collides with the flow of the refrigerant as the first guide portion 51A.

[0109] The second flow passage 32A includes the first guide portion 51A, so that the refrigerant flowing in the second flow passage 32A can efficiently flow into the first flow passage 31A. Thus, the second flow passage 32A of the second embodiment can efficiently reduce the temperature of the refrigerant flowing in the first flow passage 31A.

[0110] The third flow passage 33A includes a second guide portion 52A that guides the refrigerant flowing through the third flow passage 33A toward the first flow passage 31A.

[0111] Specifically, the third flow path 33A has a detour portion 331A formed between the second flow path forming portion 312A and the inner wall 303A of the housing 10A, and a confluence portion 332A located downstream of the detour portion 331A. Furthermore, the third flow path forming portion 313A has a portion located closer to the inner wall 303A side of the housing 10A than an imaginary line L4 formed by virtually extending the second flow path forming portion 312A along the flow direction (X-axis positive direction) of the refrigerant in the detour portion 331A. In this way, the third flow path 33A has a portion that collides with the flow of the refrigerant in the detour portion 331A as the second guide portion 52A.

[0112] The third flow passage 33A includes the second guide portion 52A, so that the refrigerant flowing in the third flow passage 33A can efficiently flow into the first flow passage 31A. Thus, the third flow passage 33A of the second embodiment can efficiently reduce the temperature of the refrigerant flowing in the first flow passage 31A.

[0113] The inventors of the present application measured the thermal resistance of the switching element 3 when the flow rate of the refrigerant was set to 6 L / min, 8 L / min, and 10 L / min, respectively. Fig.15 The results are shown in FIG. Fig.15 3 is a graph showing the relationship between the flow rate of the refrigerant and the thermal resistance of the switching element 3. Fig.15 As shown, it is shown that the thermal resistance of the switching element 3 decreases as the flow rate of the refrigerant increases.

[0114] Furthermore, the inventors of the present application calculated the respective temperatures of the switching elements 3u to 3w by simulation under the following conditions based on the above-mentioned experimental results.

[0115] <Simulation conditions>

[0116] The heat generated by the switching element 3u~3w is 650W

[0117] Refrigerant flow rate (condition 1) ... 8 L / min (the flow rate is constant in switching elements 3u to 3w)

[0118] Refrigerant flow rate (condition 2)…Switching element 3u: 6 L / min, switching element 3v: 8 L / min, switching element 3v: 10 L / min

[0119] The flow rate of condition 1 shows the flow rate of the refrigerant when cooling is performed using a cooling device without the second flow path and the third flow path. In condition 2, the flow rate of the first flow path is set to 6 L / min, and the flow rates of the second flow path and the third flow path are set to 2 L / min respectively.

[0120] Fig.16 Graph showing the results of calculating the temperatures of the switching elements 3u to 3w under conditions 1 and 2. Fig.16 As shown, when the calculation is performed under condition 1, the temperature difference between the switching element 3u disposed most upstream and the switching element 3w disposed most downstream is 5.6° C. On the other hand, when the calculation is performed under condition 2, there is almost no temperature difference between the switching elements 3u to 3w.

[0121] As is clear from these results, the cooling device including the second flow path and the third flow path in addition to the first flow path can suppress the variation in cooling temperature among the switching elements 3u to 3w.

[0122] (Other Modifications)

[0123] In the first embodiment and the second embodiment, an example of a case where the second flow path branches from the first flow path is shown, but the second flow path does not necessarily need to branch from the first flow path. Similarly, the third flow path does not necessarily need to branch from the second flow path. For example, the first flow path, the second flow path, and the third flow path may be connected to each of the multiple inlets provided in the box.

[0124] In the second embodiment, an example is shown in which the confluence portion 322A of the second flow path 32A and the confluence portion 332A of the third flow path 33A extend vertically upward toward the first flow path 31A, but the confluence portions 322A and 332A may extend obliquely toward the first flow path 31A as in the first embodiment. Thus, the temperature of the refrigerant flowing in the first flow path 31A can be efficiently reduced.

[0125] (Application example)

[0126] The power conversion device 1 according to each of the above-described embodiments may be applied to a motor system mounted on a vehicle such as a hybrid vehicle or an electric vehicle, for example.

[0127] As described above, the cooling device of the embodiment (as an example, the cooling device 100, 100A) is a cooling device for cooling a heating element, and is provided with a housing (as an example, the housing 10, 10A), a first flow path (as an example, the first flow path 31, 31A), and a second flow path (as an example, the second flow path 32, 32A). The housing has an inlet (as an example, the inlet 301, 301A) and an outlet (as an example, the outlet 302, 302A) for the refrigerant, including a first region (as an example, the first region 21) connected to the first heating element (as an example, the switching element 3u) and a second region (as an example, the second region 22) connected to the second heating element (as an example, the switching element 3v). The first flow path is a flow path connecting the inlet and the outlet, and when looking down at the housing, the first flow path overlaps with the first region and the second region. The second flow path merges with the first flow path at a position downstream of the first region and upstream of the second region. In addition, the second flow path includes a guide portion (for example, the first guide portion 51 , 51A) that guides the refrigerant flowing in the second flow path to the first flow path.

[0128] Therefore, according to the cooling device of the embodiment, it is possible to suppress the variation in cooling temperature among a plurality of cooling targets.

[0129] Furthermore, the present technology can adopt the following structures.

[0130] (1) A cooling device for cooling a heating element, comprising:

[0131] A box body having an inlet and an outlet for a refrigerant, including a first area connected to a first heating element and a second area connected to a second heating element;

[0132] a first flow path connecting the inlet and the outlet, and overlapping the first region and the second region in a plan view of the housing; and

[0133] a second flow path that merges with the first flow path at a position downstream of the first region and upstream of the second region,

[0134] The second flow path includes a guide portion that guides the refrigerant flowing in the second flow path to the first flow path.

[0135] (2) According to the cooling device described in (1), the second flow path branches off from the first flow path at a position downstream of the inlet and upstream of the first region.

[0136] (3) In the cooling device described in (1) or (2), the second flow path is arranged at a position that does not overlap with the first region and the second region when the housing is viewed in plan.

[0137] (4) In the cooling device described in (1) or (2), the first flow path and the second flow path are arranged at positions overlapping the first flow path when the housing is viewed in plan.

[0138] (5) The cooling device according to any one of (1) to (4), wherein the housing includes:

[0139] a first flow path forming portion that separates the first flow path from the second flow path; and

[0140] a second flow path forming portion disposed downstream of the first flow path forming portion and forming a merging portion where the second flow path merges with the first flow path between the second flow path forming portion and the first flow path;

[0141] The second flow path has:

[0142] a detour portion formed between the first flow path forming portion and the inner wall of the housing; and

[0143] The confluence portion is located downstream of the detour portion.

[0144] The second flow path forming portion has a portion as the guide portion located closer to the inner wall of the housing than an imaginary line obtained by imaginarily extending the first flow path forming portion along a flow direction of the refrigerant in the detour portion.

[0145] (6) The cooling device according to (5), wherein the first flow path forming portion has a first wall surface that forms the confluence portion with the second flow path forming portion,

[0146] The second flow path forming portion has a second wall surface that forms the confluence portion with the first wall surface.

[0147] The first wall surface and the second wall surface extend obliquely toward the first flow path.

[0148] (7) The cooling device according to any one of (2) to (6), further comprising a third flow path branched from the second flow path and joined to the first flow path,

[0149] The box also includes a third area connected to the third heating element

[0150] When the housing is viewed from above, the first flow path overlaps with the first region, the second region, and the third region of the housing.

[0151] The third flow path branches off from the second flow path at a position upstream of the second region, and merges with the first flow path at a position downstream of the second region and upstream of the third region.

[0152] (8) According to the cooling device described in (7), the flow path cross-sectional area of ​​the branch portion of the above-mentioned second flow path branching from the above-mentioned first flow path is smaller than the flow path cross-sectional area of ​​the above-mentioned first flow path, and is larger than the flow path cross-sectional area of ​​the branch portion of the above-mentioned third flow path branching from the above-mentioned second flow path.

[0153] (9) A semiconductor device comprising:

[0154] A box body having an inlet and an outlet for a refrigerant;

[0155] a first flow path connecting the inlet and the outlet, and overlapping the first area and the second area of ​​the housing when the housing is viewed from above;

[0156] A first semiconductor element, which is disposed in the first region;

[0157] A second semiconductor element is disposed in the second region; and

[0158] a second flow path that merges with the first flow path at a position downstream of the first region and upstream of the second region,

[0159] The second flow path includes a guide portion that guides the refrigerant flowing in the second flow path to the first flow path.

[0160] (10) The semiconductor device according to (9), further comprising a third flow path branched from the second flow path and joined to the first flow path,

[0161] When the housing is viewed from above, the first flow path overlaps with the first region, the second region, and the third region of the housing.

[0162] further comprising a third semiconductor element disposed in the third region,

[0163] The third flow path branches off from the second flow path at a position upstream of the second region, and merges with the first flow path at a position downstream of the second region and upstream of the third region.

[0164] (11) According to the semiconductor device described in (10), the housing includes:

[0165] a main body having a groove constituting an inner wall surface of at least a part of the first flow path, the second flow path, and the third flow path; and

[0166] A plate-shaped substrate having a first surface and a second surface located on the opposite side of the first surface, wherein the second surface closes the open portion of the groove.

[0167] The first semiconductor element, the second semiconductor element, and the third semiconductor element are disposed on the first surface of the substrate, and a plurality of fins are provided on the second surface of the substrate.

[0168] (12) In the semiconductor device described in (10) or (11), the first semiconductor element, the second semiconductor element, and the third semiconductor element are insulated gate bipolar transistors or power MOSFETs.

[0169] It should be considered that the embodiments disclosed this time are only examples in all aspects and are not restrictive. In fact, the above embodiments can be specifically implemented in many ways. In addition, the above embodiments can be omitted, replaced, and changed in various ways without departing from the scope of the attached claims and their purport.

[0170] Explanation of symbols

[0171] 1—power conversion device, 2—motor, 3—switching element, 4—diode, 5—gate driver, 10—housing, 20—substrate, 21—first region, 22—second region, 23—third region, 25—fin, 30—main body, 31—first flow path, 32—second flow path, 33—third flow path, 51—first guide portion, 52—second guide portion, 100—cooling device, 301—inlet, 302—outlet, 303—inner wall, 311—first flow path forming portion, 312—second flow path forming portion, 313—third flow path forming portion, 321—detour portion, 322—merging portion, 331—detour portion, 332—merging portion.

Claims

1. A cooling device for cooling a heating element, characterized in that: have: A box body having an inlet and an outlet for a refrigerant and including a first area connected to a first heating element and a second area connected to a second heating element; a first flow path connecting the inlet and the outlet, and overlapping the first region and the second region in a plan view of the housing; and a second flow path that merges with the first flow path at a position downstream of the first region and upstream of the second region, The second flow path includes a guide portion that guides the refrigerant flowing in the second flow path to the first flow path.

2. The cooling device according to claim 1, characterized in that: The second flow path branches off from the first flow path at a position downstream of the inlet and upstream of the first region.

3. The cooling device according to claim 1, characterized in that: The second flow path is arranged at a position that does not overlap with the first region and the second region when the housing is viewed in plan.

4. The cooling device according to claim 1, characterized in that: The first flow path and the second flow path are arranged at positions overlapping with the first flow path in a plan view of the housing.

5. The cooling device according to claim 1, characterized in that: The above-mentioned box has: a first flow path forming portion that separates the first flow path from the second flow path; and a second flow path forming portion disposed downstream of the first flow path forming portion and forming a merging portion where the second flow path merges with the first flow path between the second flow path forming portion and the first flow path; The second flow path has: a detour portion formed between the first flow path forming portion and the inner wall of the housing; and The confluence portion is located downstream of the detour portion. The second flow path forming portion has a portion as the guide portion located closer to the inner wall of the housing than an imaginary line obtained by imaginarily extending the first flow path forming portion along a flow direction of the refrigerant in the detour portion.

6. The cooling device according to claim 5, characterized in that: The first flow path forming portion has a first wall surface that forms the confluence portion with the second flow path forming portion. The second flow path forming portion includes a second wall surface that forms the confluence portion with the first wall surface. The first wall surface and the second wall surface extend obliquely toward the first flow path.

7. The cooling device according to claim 2, characterized in that: further comprising a third flow path branching from the second flow path and merging with the first flow path, The box body also includes a third area connected to the third heating element. When the housing is viewed from above, the first flow path overlaps with the first region, the second region, and the third region of the housing. The third flow path branches off from the second flow path at a position upstream of the second region, and merges with the first flow path at a position downstream of the second region and upstream of the third region.

8. The cooling device according to claim 7, characterized in that: A flow path cross-sectional area of ​​a branch portion of the second flow path branched from the first flow path is smaller than a flow path cross-sectional area of ​​the first flow path, and is larger than a flow path cross-sectional area of ​​a branch portion of the third flow path branched from the second flow path.

9. A semiconductor device, characterized in that: have: A box body having an inlet and an outlet for a refrigerant; a first flow path connecting the inlet and the outlet, and overlapping the first area and the second area of ​​the housing when the housing is viewed from above; A first semiconductor element, which is disposed in the first region; A second semiconductor element disposed in the second region; as well as a second flow path that merges with the first flow path at a position downstream of the first region and upstream of the second region, The second flow path includes a guide portion that guides the refrigerant flowing in the second flow path to the first flow path.

10. The semiconductor device according to claim 9, wherein: further comprising a third flow path branching from the second flow path and merging with the first flow path, When the housing is viewed from above, the first flow path overlaps with the first region, the second region, and the third region of the housing. further comprising a third semiconductor element disposed in the third region, The third flow path branches off from the second flow path at a position upstream of the second region, and merges with the first flow path at a position downstream of the second region and upstream of the third region.

11. The semiconductor device according to claim 10, wherein: The above-mentioned box has: a main body having a groove constituting at least a part of the inner wall surface of the first flow path, the second flow path, and the third flow path; and A plate-shaped substrate having a first surface and a second surface located on the opposite side of the first surface, wherein the second surface closes the open portion of the groove. The first semiconductor element, the second semiconductor element, and the third semiconductor element are arranged on the first surface of the substrate, and a plurality of fins are provided on the second surface of the substrate.

12. The semiconductor device according to claim 10 or 11, characterized in that: The first semiconductor element, the second semiconductor element, and the third semiconductor element are insulated gate bipolar transistors or power MOSFETs.

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