JP2010140964A - Radiator for semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve radiation performance of a radiator for a semiconductor device, while controlling the increase in the pressure drop. <P>SOLUTION: The radiator includes: a casing 20, provided with an ingress and egress for a coolant; an insulating substrate 24 prepared on one outer surface of the casing 20, to which an IGBT 17 (insulated gate bipolar transistor) is attached; and a corrugated fin 30, whose respective apices are joined to the inner surface of the side opposite to the one where the casing 20s insulating substrate 24 is attached, which prescribes the coolant flow passage 37, wherein as to the corrugation fin 30, the direction in which each apex extends is a straight line, that part corresponding to the part of the casing 20, to which the insulating substrate 24 is attached is divided into two or more blocks 31a to 31b and 32a to 32c, in a direction in which the coolant flows by a slit 34 set up at right angle with the direction in which the coolant flows, and the corrugated fin 30 of respective adjoining blocks is arranged so that its pitch is shifted in a right angle direction with the direction in which the coolant flows. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a semiconductor device cooler.

  In recent years, hybrid vehicles using a combination of two types of drive sources, that is, an engine and a motor generator, as a vehicle drive source, and electric vehicles that drive a vehicle with a motor generator have been increasingly used. In such an electric vehicle, a chargeable / dischargeable secondary battery and the DC power of the secondary battery are converted into three-phase AC power for driving the motor generator and output, and the AC power regenerated by the motor generator is secondary An inverter that is a power converter for charging the battery is mounted. The inverter performs power conversion by the switching operation of the switching element, but generates large heat during the switching operation. In addition to an inverter, an electric vehicle may be equipped with a boost converter or a DC / DC converter that converts a DC voltage. These converters also use switching elements that generate a large amount of heat during operation. . As the switching element, a power transistor is often used. For example, an insulated gate bipolar transistor (IGBT) or the like is used.

  In an electric device such as an inverter using such a highly exothermic semiconductor element, a cooler is attached in order to remove heat generated in the semiconductor element and bring the semiconductor element to an appropriate operating temperature. For example, a cooling method is proposed in which a corrugated fin for heat dissipation is attached to a circuit board for a power module, the corrugated fin is cut by dividing in the wavelength direction, and the pitch between adjacent fins is shifted with each cut being sandwiched. (For example, refer to Patent Document 1).

  Also, in a cooler configured with a coolant channel by sandwiching folded plates with zigzag plate members sandwiched from both sides, slits on the side surfaces of the folded plates are opened, and the plates between the slits are raised by a predetermined angle to form a louver. It has been proposed to improve heat exchange efficiency by alternately providing bulging portions on the folded plate (see, for example, Patent Document 2).

JP 2006-310486 A JP 2002-5591 A

  On the other hand, the heat transfer coefficient and the resistance of the flow path are in a contradictory relationship, and trying to improve the heat dissipation performance by improving the heat transfer coefficient increases the flow path resistance, increasing the pump discharge pressure or piping It is necessary to increase the diameter, and on the contrary, the apparatus may become large and cost may increase.

  In the method of disposing the corrugated fins with the pitches described in Patent Document 1, the slits are arranged substantially evenly over the entire length of the refrigerant flow path. There is a problem that the flow path is bent, and the fluid resistance increases for an increase in the heat radiation amount.

  In addition, the prior art described in Patent Document 2 provides a louver substantially evenly on the side surface of the folded plate or alternately swells the folded plate at substantially equal intervals. However, there is a problem that the increase in fluid resistance becomes large.

  Accordingly, an object of the present invention is to improve heat dissipation performance while suppressing an increase in pressure loss.

  The cooler for a semiconductor element of the present invention includes a casing provided with a refrigerant inlet and a refrigerant outlet, an insulating substrate provided on one outer surface of the casing, to which the semiconductor element is attached, and a surface to which the insulating substrate of the casing is attached. Corrugated fins each having a top joined to the inner surface on the opposite side and defining a coolant flow path, the corrugated fins extending in a straight line and corresponding to a portion of the casing to which the insulating substrate is attached The portion is divided into a plurality of blocks in the refrigerant flow direction by slits provided in a direction perpendicular to the refrigerant flow direction, and the corrugated fins of each adjacent block are arranged with a pitch shifted in a direction perpendicular to the refrigerant flow direction. It is characterized by that.

  In the cooler for semiconductor elements of the present invention, a plurality of insulating substrates are provided on the outer surface of the casing along the direction of the flow of the refrigerant, and the corrugated fins in the corresponding casing portion between the insulating substrates are one block. This is also preferable.

  In the semiconductor element cooler of the present invention, the semiconductor element is attached to the outer surface of the casing on the refrigerant inlet side and the outer surface of the refrigerant outlet side, and the corrugated fins are upstream, downstream, upstream, and downstream of the refrigerant flow path. The upstream portion and the downstream portion are divided into a plurality of blocks in the refrigerant flow direction by slits provided in a direction perpendicular to the refrigerant flow direction, and corrugated fins of adjacent blocks. Are arranged with a pitch shifted in a direction perpendicular to the direction in which the refrigerant flows, and the corrugated fins in the middle are preferably one block.

  The present invention has an effect that heat dissipation performance can be improved while suppressing an increase in pressure loss.

  Preferred embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the cooler 10 of this embodiment is provided with an inlet channel 11 and an outlet channel 14, and a casing 20 through which a refrigerant such as LLC flows.

  As shown in FIG. 2, the casing 20 includes an aluminum top plate 21 and a bottom plate 22. The top plate 21 is provided around a flat plate 21a and a flat plate 21a to which an IGBT (insulated gate bipolar transistor) 17 as a semiconductor element is attached, and is provided on a skirt portion 21b and a skirt portion 21b extending from the flat plate 21a toward the bottom plate 22. And a flange 21c. The bottom plate 22 is a flat plate made of aluminum, and the flange 21c of the top plate 21 is attached to the bottom plate 22 by brazing. Between the flat plate 21 a and the bottom plate 22 inside the casing 20, a corrugated fin 30 is attached by brazing 38 so that a U-shaped peak 35 and valley 36 are continuous. Between the peak part 35 and the valley part 36 is a flow path 37 through which the refrigerant flows. The corrugated fin 30 is formed by forming an aluminum plate having a thickness of 0.3 mm so that the height between the fins is about 5 mm and the gap between the fins is 0.9 mm. The corrugated fin 30 is a straight fin in which the crest 35 and the trough 36 extend linearly.

  As shown in FIG. 2, a buffer material 23 made of a porous aluminum plate is attached to the outer surface of the flat plate 21 a, and an insulating substrate 24 is attached on the buffer material 23. The insulating substrate 24 is made of ceramic, and a thin aluminum plate is attached to both surfaces by clad. One of the aluminum clads 25 of the insulating substrate 24 is brazed to the buffer material 23, and the IGBT 17 and the diode 18 are attached to the other surface. The buffer material 23 reduces the difference in thermal expansion between the aluminum flat plate 21a and the ceramic insulating substrate 24.

  As shown in FIG. 3, end surfaces 13 and 16 of the casing 20 in the extending direction of the corrugated fins 30 are open ends, and the inlet channel 11 and the outlet channel 14 are connected. The refrigerant flowing into the inlet channel 11 from the refrigerant inlet 12 shown in FIG. 1 enters the channel 37 defined by the corrugated fins 30 inside the casing 20 from the end surface 13 of the casing 20 and flows out from the end surface 16 to the outlet channel 14. However, it flows out from the refrigerant outlet 15 shown in FIG.

  As shown in FIG. 3, the corrugated fin 30 includes an upstream portion 31, a downstream portion 32, and an intermediate portion 33 between the upstream portion 31 and the downstream portion 32. The length of the upstream part 31 and the downstream part 32 is about 1/4 of the whole flow path length. The upstream portion 31 and the downstream portion 32 are further divided into three blocks 31a to 31c and 32a to 32c by a slit 34 extending in a direction perpendicular to the direction in which the refrigerant flows. The width of each slit is approximately 1.0 mm. This is because when the width of the slit 34 is 0.9 mm or more, clogging of the slit 34 due to foreign matter in the refrigerant can be prevented. In addition, when the width of the slit 34 is 1.5 mm or more, the cooling performance is greatly deteriorated. Therefore, the width is set to 1.0 mm with a margin close to 0.9 mm.

  As shown in FIGS. 4 and 2, adjacent blocks 31a and 31b of the upstream portion 31 of the corrugated fin 30 are arranged such that the crests 35 and the troughs 36 of each block are shifted in a direction perpendicular to the refrigerant flow direction. Has been. In the present embodiment, the ridges 35 of the block 31a are shifted by half the pitch of the ridges 35 or the valleys 36 so that the ridges 35 of the block 31b become the valleys 36. The arrangement between the block 31b and the block 31c in the upstream portion 31 is the same as that between the block 31a and the block 31b. For this reason, the pitches of the peak portions 35 and the valley portions 36 of the corrugated fins 30 of the block 31a and the block 31c are aligned without deviation. Each block 32a-32c of the downstream part 32 has the same arrangement as the blocks 31a-31c of the upstream part 31. Further, the pitches of the peak portions 35 and the valley portions 36 of the corrugated fins 30 of the block 31c downstream of the upstream portion 31 and the block 32c upstream of the downstream portion 32 are aligned without deviation.

  The intermediate portion 33 between the upstream portion 31 and the downstream portion 32 is disposed via the slit 34 between the upstream portion 31 and the downstream portion 32, and the peak portion 35 and the valley portion 36 of the corrugated fin 30 of the intermediate portion 33 Are arranged so as to deviate from the pitch between the crests 35 and the troughs 36 of the corrugated fins 30 of the block 31c on the downstream side of the upstream part 31 and the block 32c on the upstream side of the downstream part 32. In this embodiment, the pitch is shifted by a half pitch of the pitch of the peak portion 35 or the valley portion 36. As shown in FIG. 3, an insulating substrate 24 to which the IGBT 17 and the diode 18 are attached is attached to the flat plate 21 a of the casing 20 corresponding to the upstream portion 31 and the downstream portion 32. For this reason, it is necessary for the upstream portion 31 and the downstream portion 32 to absorb the heat generated from the IGBT 17 and the like into the refrigerant. However, as shown in FIG. 1, the AC bus bar 19 is disposed above the casing 20 corresponding to the intermediate portion 33. Since a heating element such as IGBT 17 is not attached, the refrigerant does not need to absorb heat.

  The flow of the refrigerant in the cooler 10 configured as described above will be described. The refrigerant that has entered the inlet channel 11 from the refrigerant inlet 12 shown in FIG. 1 flows into the casing 20 from the end face 13 of the casing 20. As shown in FIG. 4, the refrigerant first flows into the flow path 37 of the block 31 a on the upstream side of the upstream portion 31. The refrigerant cools the corrugated fins 30 while flowing through the flow path 37 and absorbs heat generated by the IGBT 17 and the diode 18. The refrigerant that has flowed through the flow path 37 of the block 31 a flows out of the block 31 a and enters the slit 34. The pitch of the crests 35 or troughs 36 of the block 31b is shifted by a half pitch from the pitch of the crests 35 or troughs 36 of the block 31a. Further, since the fin thickness is 0.3 mm and the inter-surface dimension of the fins constituting the flow path 37 is 0.9 mm, the refrigerant flowing out of the block 31a hits the end face of the corrugated fin 30 of the block 31b, and left and right It flows separately and flows into the flow path 37 of the block 31b. In this way, the flow of the refrigerant is disturbed at the slit 34, whereby a turbulent flow is generated inside the block 31b. The turbulent flow promotes heat exchange between the corrugated fins 30 of the block 31b and the refrigerant. Then, the refrigerant that has flowed out of the block 31b is divided into left and right through the slit 34, and flows into the block 31c whose pitch with the peak 35 or valley 36 of the corrugated fin 30 is shifted by a half pitch, and becomes turbulent again. It flows through the block 31 c and absorbs the heat of the IGBT 17 or the diode 18. Then, the refrigerant that has flowed out of the block 31 c enters the slit 34 again, divides left and right, and flows into the flow path 37 of the intermediate portion 33.

  The intermediate part 33 is one block, and the flow path is straight. For this reason, the refrigerant gradually disappears and becomes a laminar flow and flows through the intermediate portion 33. The intermediate portion 33 does not need to absorb heat because a heating element such as the IGBT 17 is not attached to the upper surface of the intermediate portion 33. For this reason, it is more effective to stabilize the flow and reduce the channel resistance than to disturb the flow and improve the heat transfer characteristics. Since the fluid flows as a laminar flow in the intermediate portion 33, the heat absorption is low, but the resistance of the fluid is also reduced.

  Then, the refrigerant that has flowed out of the intermediate portion 33 enters the slit 34 again, diverges left and right, and enters a block 32c on the upstream side of the downstream portion 32. And as it flowed through each block 31a-31c of the upstream part 31, every time it enters the slit 34, a refrigerant | coolant is divided into right and left, and becomes a turbulent flow, flows through each block 32c-32a, and the end surface of the casing 20 shown in FIG. 16 flows into the outlet channel 14. The refrigerant that has flowed into the outlet channel 14 flows out from the refrigerant outlet 15 shown in FIG.

  In the present embodiment described above, the upstream portion 31 and the downstream portion 32 of the corrugated fin 30 corresponding to the casing 20 of the portion provided with the insulating substrate 24 to which the heating element such as the IGBT 17 is attached include a plurality of blocks 31a to 31c. , 32a to 32c, and the pitches of the crests 35 or troughs 36 of the fins of adjacent blocks are shifted, so that the heat dissipation performance is improved and the casing 20 in the portion where the insulating substrate 24 is not provided. The intermediate part 33 of the corrugated fin 30 corresponding to the above forms a straight flow path 37 as one block so as to reduce the flow resistance. For this reason, this embodiment has an effect that heat dissipation performance can be improved while suppressing an increase in pressure loss.

  In the present embodiment, the slit 34 is provided in a portion corresponding to a portion of the ceramic insulating substrate 24 to which the IGBT 17 and the diode 18 are attached. When the IGBT 17 and the diode 18 generate heat, the temperatures of the insulating substrate 24 and the flat plate 21a of the casing 20 rise. In this case, the amount of thermal expansion of the ceramic insulating substrate 24 is smaller than that of the flat plate 21a of the aluminum casing 20, and a difference in thermal expansion occurs between the insulating substrate 24 and the flat plate 21a, and the flat plate 21a is bent and deformed in the vertical direction. To try. The slit 34 prevents the corrugated fins 30 fixed to the flat plate 21a and the bottom plate 22 by brazing from acting as a reinforcing member of the flat plate 21a and resisting bending deformation, so that the thermal expansion between the insulating substrate 24 and the flat plate 21a. The difference is absorbed by the bending deformation of the flat plate 21a, and the ceramic insulating substrate 24 can be prevented from being damaged.

It is a top view of the cooler for semiconductor elements in the embodiment of the present invention. It is sectional drawing of the orthogonal | vertical direction with the flow path of the semiconductor element cooler in embodiment of this invention. It is sectional drawing of the flow-path direction of the semiconductor element cooler in embodiment of this invention. It is a top view which shows the corrugated fin of the semiconductor element cooler in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cooler, 11 Inlet flow path, 12 Refrigerant inlet, 13,16 End surface, 14 Outlet flow path, 15 Refrigerant outlet, 17 IGBT, 18 Diode, 19 AC bus bar, 20 Casing, 21 Top plate, 21a Flat plate, 21b Skirt part , 21c flange, 22 bottom plate, 23 cushioning material, 24 insulating substrate, 25 aluminum clad, 30 corrugated fin, 31 upstream part, 31a-31c block, 32 downstream part, 32a-32c block, 33 intermediate part, 34 slit, 35 ridges Part, 36 valley part, 37 flow path, 38 brazing.

Claims (3)

A casing provided with a refrigerant inlet and a refrigerant outlet;
An insulating substrate provided on one outer surface of the casing and to which a semiconductor element is attached;
Corrugated fins each of which is joined to the inner surface opposite to the surface on which the insulating substrate of the casing is attached, and which defines a refrigerant flow path,
Corrugated fins are straight in the direction in which each apex extends,
A portion corresponding to the portion of the casing to which the insulating substrate is attached is divided into a plurality of blocks in a direction in which the refrigerant flows by a slit provided in a direction perpendicular to the direction of the refrigerant flow. The pitch is shifted in the direction perpendicular to the direction of flow of
A cooler for semiconductor elements. A cooler for a semiconductor device according to claim 1,
A plurality of insulating substrates are provided on the outer surface of the casing along the direction of the refrigerant flow, and the corrugated fins of the corresponding casing portion between the insulating substrates are one block,
A cooler for semiconductor elements. A cooler for a semiconductor device according to claim 2,
The semiconductor element is attached to the outer surface on the refrigerant inlet side and the outer surface on the refrigerant outlet side of the casing,
The corrugated fin includes an upstream portion and a downstream portion of the refrigerant flow path, and an intermediate portion between the upstream portion and the downstream portion, and the upstream portion and the downstream portion are formed by a slit provided in a direction perpendicular to the direction of the refrigerant flow. The corrugated fins of each adjacent block are arranged with a pitch shifted in the direction perpendicular to the direction of refrigerant flow, and the corrugated fin in the middle part is one block,
A cooler for semiconductor elements.

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