Electronics cooler, electronics device and inverter with an electronics cooler

Abstract

Disclosed is an electronics cooler (KL) for cooling an electronic device (EV), comprising: - a cooling channel (KN) for passing a liquid coolant; - a cooler part (KT) which at least partially encloses the cooling channel (KN); - an insert body (EK) which is arranged in the cooling channel (KN) and is designed to reversibly expand or shrink depending on the temperature of the coolant flowing through the cooling channel (KN) and thus to regulate or change the flow of the coolant through the cooling channel (KN). Furthermore, an electronic device (EV) with a said cooler (KL) and an inverter with a said electronic device (EV) are described.

Description

Technical Field:The present invention relates to a (power) electronics cooler or a cooler for cooling a (power) electronics device, for example a (power) MHDC converter or a (power) radiator, in particular an electrically driven vehicle. The invention further relates to a (power) electronic device having a said cooler and to a (power) inverter having a said (power) electronic device.STATE OF THE ART AND OBJECT OF THE INVENTIONElectronics coolers for cooling an electronics device are known and are used, inter alia, in (power) DCDC converters or (power) inverters for cooling the electronics devices or power modules (having a plurality of power semiconductor switches or comparable circuit components with high power losses) of the DCDC converters or the inverters.Such coolers are used, for example, in inverters of electrically driven vehicles for cooling the inverters or their power modules (having a plurality of power semiconductor switches).The document DE 10 2018 218 049 A1 describes a cooling module for a vehicle control device, which has a cooling body with a cooling channel for passing a coolant through, in which cooling ribs are arranged. The cooling module further comprises a bimetallic composite in the cooling channel, which adjusts the cooling ribs depending on the temperature in the cooling channel.The publication DE 10 2014 213 108 B3 describes a power module which has a housing with a cavity in which a power semiconductor is arranged. The cavity is filled with a thermally conductive electrically insulating medium. The housing has ribs or pins that extend into the cavity.US 2016 / 0 223 274 A1 describes a heat exchanger which has two flow channels for conducting in each case one of two fluids which are fluidically separated from one another, and a heat exchange body which is configured to exchange the heat between the two fluids.With the ever-increasing power requirement for the above-mentioned electronic devices, the requirement for efficient cooling of these electronic devices also increases. In particular, in electronic devices using high-power semiconductors such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN) power semiconductors, the requirement for efficient cooling is particularly high.The object of the present application is thus to provide a possibility with which a (power) electronic device, for example a (power) converter or a (power) HVDC converter, can be efficiently cooled.DESCRIPTION OF THE INVENTIONThis object is achieved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.According to a first aspect of the invention, a (power) electronics cooler or a cooler for cooling a (power) electronics device, for example a (power DCDC) converter or a (power) radiator, in particular an electrically driven vehicle, is provided.The cooler has at least one cooling duct for passing a liquid coolant, such as cooling water, for example, and at least one cooler part which at least partially surrounds the cooling duct (in its periphery). The cooler part forms part of a duct wall of the cooling duct and absorbs the waste heat from the electronics device during operation thereof and forwards the absorbed waste heat to the coolant flowing through the duct. The cooler part can have a, preferably planar, surface on a side facing away from the cooling channel, on which surface the electronics device to be cooled or a part thereof can be arranged and thermally connected to the latter. In this case, the cooler part also has the function of a circuit carrier or can also be formed as a circuit carrier with corresponding circuit structures, such as e.g. conductor tracks.The cooler further comprises an insert body which is arranged in the cooling duct and is configured to reversibly expand or shrink depending on the temperature of the coolant flowing through the cooling duct and thus to regulate or change the flow rate of the coolant through the cooling duct. The insert body is arranged in a floating manner in the cooling channel and is not held immovably, in particular, on the cooler part or on other components of the cooler.For this purpose, the insert body is formed as a three-dimensional structure of a material (or material mixture) with a high coefficient of thermal expansion which can be reversibly expanded and shrunk depending on the intrinsic temperature or the ambient temperature and acts like a partial barrier in the cooling duct with a barrier surface (or transverse surface which changes depending on the temperature and lies transversely to the flow direction of the coolant). The high coefficient of expansion of the insert body is sufficient in this case for the insert body to expand or shrink markedly in the event of a coolant temperature fluctuation and thus to change the throughflow area or the throughflow cross section in the cooling duct region of the insert body and thus also the throughflow through the cooling duct markedly.In the case of a low coolant temperature or a coolant temperature drop, the insert body shrinks, whereby the flow area or the flow cross section of the cooling channel in the channel region, where the insert body is located, increases. As a result, the flow velocity of the coolant and thus also the pressure loss in the coolant decrease. Accordingly, the pressure loss in the coolant at a low coolant temperature is limited. Thus, with the same coolant pumping capacity, more coolant can flow through the cooling channel, whereby the cooling efficiency at low coolant temperature is increased. The insert body acts as a partial barrier to the coolant flow in the cooling channel and reduces or prevents the pressure loss in the coolant flowing through the cooling channel at a low coolant temperature and thus increases the cooling efficiency at a low coolant temperature.At a high coolant temperature, the insert body expands, so that the flow area in the channel region where the insert body is located decreases, as a result of which the flow speed and the pressure loss in the coolant flowing through the cooling channel also increase. However, the pressure loss at a high coolant temperature is not critical or less critical (than at a low coolant temperature) and thus represents no or hardly any problem for efficient cooling.This creates a coolant temperature-controlled flow design for the cooler, whereby a (power) electronic device, for example a (power) converter or a (power) HVDC converter, can be efficiently cooled.The insert body has, for example, a coefficient of thermal expansion which is higher by at least 50% or by at least 100% or by at least 200% than the coefficient of expansion of the cooler part or is at least five times or at least ten times the coefficient of expansion of the cooler part.The insert body can be made of silicone or a comparable material with a similarly high coefficient of thermal expansion or contain silicone or a comparable material with a similarly high coefficient of thermal expansion as the main material.The insert body can have a shape adapted to the cooling channel or its channel wall surface, which allows the insert body to be held floatingly at a defined location in the cooling channel.The cooler part can also have at least one section, such as in the form of a projection, for example a pin-shaped projection, on which the insert body is not held displaceably in the longitudinal direction of the cooling duct, which is generally the main flow direction of the coolant in the cooling duct. The portion does not immovably hold the insert body, but prevents the insert body from slipping in the longitudinal direction of the cooling passage or floating away from the predetermined position in the longitudinal direction of the cooling passage.The insert body has in particular sufficient mechanical rigidity, so that during cooler operation of the cooler and despite the pressure of the coolant flowing through the cooling duct, it remains at the predetermined position in the cooling duct and additionally retains its basic shape and only expands or shrinks in this basic shape.The cooler part can, for example, be arranged in the same way as a radiator. having cooler pins for increasing the cooling surface area of the cooler part. In this case, one or more of the cooler pins can form the abovementioned section which prevents the insert body from slipping or floating away in the longitudinal direction of the cooling duct.Analogously, the insert body can also have a surface structure for enlarging the surface of the insert body, for example in the form of pin-shaped projections.The surface structure of the insert body can extend in the direction of the cooler pins as far as into intermediate spaces formed between the cooler pins. In this case, the surface structure of the insert body and the cooler pins on the cooler part loosely engage in one another, as a result of which the insert body is prevented from slipping in the longitudinal direction of the cooling duct.The surface structure of the insert body can thereby generate (microscal) vortices-turbulent flows, in particular turbulent boundary layer flows-and thus additionally increase the cooling efficiency.In the case that the surface structure on the insert body has pin-shaped projections, these projections can expand and shrink depending on the coolant temperature and thus partially block the cooling duct and thus regulate or change the flow through the cooling duct.The insert body can furthermore be shaped in such a way that this flow of the coolant can be varied in a direction transverse to the longitudinal direction of the cooling duct.According to an exemplary embodiment of the cooler, the cooling channel may comprise two or more parallel channel sections. In this case, the insert body can furthermore be configured in such a way that it regulates or changes the flow ratio of the coolant flows of the coolant flowing through the two channel sections depending on the temperature of the coolant or of the coolant flowing through one of the two channel sections.According to an exemplary embodiment of the cooler, it can have a plurality of insert bodies with different coefficients of expansion, which are arranged one behind the other at different positions in the cooling duct distributed in the longitudinal direction of the cooling duct, or, in the case of a plurality of parallel duct sections, are arranged distributed in these duct sections.According to a second aspect of the invention, an electronic device or a power electronic device is provided which forms, for example, a part of a (power) converter or a (power) CCD converter.The electronics device has at least one electronics module (or power electronics module) and at least one previously described cooler for cooling the at least one electronics module, wherein the at least one electronics module is in thermal, especially physical, contact with the at least one cooler.According to a third aspect of the invention, an inverter or a power inverter is provided, which comprises a previously described (power) electronic device and an inverter driver circuit for operating the at least one (power) inverter of the (power) electronic device. The driver circuit is connected to the at least one (power) driver circuit by means of at least one signal connection in terms of signal technology or electrically.In addition, a DC / DC converter or a power DC / DC converter is provided, which has a previously described (power) electronic device and a DC / DC converter driver circuit for operating the at least one (power) power source of the (power) electronic device. The driver circuit is connected to the at least one (power) driver circuit by means of at least one signal connection in terms of signal technology or electrically.DESCRIPTION OF THE DRAWINGAn exemplary embodiment of the invention is explained in more detail below with reference to the accompanying drawing. The only one is shown here FIG. 1 shows a schematic cross-sectional illustration of a (power) electronic device EV having a cooler KL according to the exemplary embodiment of the invention. The device EV forms, for example, a power electronics part of a power inverter for an electric drive of a motor vehicle and is electrically connected via signal connections to a driver / control circuit of the power inverter, not shown in the figure.The device EV has a power electronics module EM (or else a plurality of power electronics modules) with SiC semiconductor switches and a cooler KL for cooling the device EV or the module EM (or the modules).The radiator KL has a radiator part KT as a cooling duct cover and a radiator base KB and radiator side parts (not shown in the figure), which together have a cooling duct KN for passing a coolant, for example. Form cooling water and enclose this cooling channel KN except for an inlet and an outlet (both not shown in the figure). Here, the radiator KL may be made of aluminum or an aluminum alloy in an extrusion process.The power electronics module EM is arranged on a surface OF 2 of the cooler part KT facing away from the cooling channel KN and is physically and thermally connected to the latter. In an alternative embodiment, the cooler part KT can be formed directly as a circuit carrier of the module EM and thus as a part of the module EM.Furthermore, the cooler part KT has, on a surface OF 1 facing the cooling duct KN, a multiplicity of cooler pins VS 1 (in the form of first pin-shaped projections) which extend away from the surface OF 1 into the cooling duct KN or in the direction of the cooler base KB. The cooler pins VS 1 contribute firstly to enlarging the surface area OF 1 of the cooler part KT around which the coolant flows and thus to better and efficient heat transfer from the cooler part KT to the coolant. On the other hand, some of the cooler pins VS 1 form sections which keep an insert body EK, which will be described in more detail below, floating in the predetermined position in the cooling duct KN, such that the insert body EK cannot slip in the longitudinal direction LR of the cooling duct KN or in the direction of flow or main direction of flow of the coolant and float away from the predetermined position.The radiator KL further comprises the aforementioned insert body EK, which is formed as a one-piece three-dimensional structure and is held in the cooling channel KN such that it cannot be displaced in the longitudinal direction LR of the cooling channel KN or in the flow direction of the coolant in the cooling channel KN by the aforementioned sections or the some radiator pins VS 1. Here, the insert body EK likewise has a surface structure in the form of second pin-shaped projections VS 2 for enlarging the surface of the insert body EK, which extend in the direction of the surface OF 1 of the cooler part KT and into spaces ZR which are formed between the cooler pins VS 1. With the intersections or the cooler pins VS 1 of the cooler part KT, the projections VS 2 prevent the insert body EK from floating in the longitudinal direction LR of the cooling channel KN or in the flow direction of the coolant.The insert body EK is predominantly made of silicone and has a high coefficient of thermal expansion, which is for example a thermal expansion coefficient. Three times to seven times the thermal expansion coefficient of the cooler KL or of the cooler part KT.Due to the high coefficient of thermal expansion, the insert body EK is able to reversibly expand or shrink by 30% up to 100% of its volume, in particular the length of its pin-shaped projections VS 2, in the event of a temperature fluctuation of a few tens of degrees, and thus to regulate or change the throughflow area of the cooling duct KN in the region of the insert body EK and thus the throughflow of the coolant through the cooling duct KN.The insert body EK can be formed such that it extends over the entire length of the cooling channel KN (between the inlet and outlet thereof). Alternatively, the insert body EK can extend only in a predetermined subsection of the cooling channel KN.In a further embodiment, the cooler KL can have a plurality of insert bodies EK with different sizes, shapes and / or coefficients of expansion, which are arranged one behind the other distributed in the longitudinal direction LR of the cooling duct KN at different, predetermined positions in the cooling duct KN. In this case, the positions of the respective insert bodies EK can be defined in advance as a function of the local power losses of the power electronics module EM (or of the power electronics modules).Further, the insert body EK, such as having lateral protrusions extending transversely to the longitudinal direction LR, may be shaped to change the flow of the coolant in a direction transverse to the longitudinal direction LR of the cooling channel KN.In a further embodiment, the cooling channel KN can have two or more parallel channel sections. In this case, the insert body EK can be arranged in one of the two channel sections and thus regulate or change the flow ratio of the coolant flows of the coolant flowing through the two channel sections by a coolant-temperature-dependent change in the flow area in this channel section. In the case of a plurality of insert bodies EK with different coefficients of expansion, these can be arranged distributed in the channel sections.During operation of the device EV, the waste heat generated by the power semiconductors of the module EM is discharged via the cooler part KT to the coolant flowing through the cooling duct KN. In this case, the temperature of the insert body EK matches the ambient temperature or the temperature of the coolant flowing past the insert body EK. As a result of the high coefficient of expansion, the insert body EK expands or shrinks greatly depending on the temperature than the cooler KL itself (or the cooler part KT, the cooler base KB and the cooler side parts).At a low temperature or a temperature drop, the insert body EK shrinks much or more strongly than the cooler KL itself (or the cooler part KT, the cooler base KB and the cooler side parts). As a result, the flow area of the cooling channel increases in the channel region where the insert body EK is located, and as a result, the flow speed of the coolant and also the pressure loss in the coolant in the cooling channel KN or at the said channel region decrease. As a result, the pressure loss in the refrigerant at a low refrigerant temperature is limited. Thus, with the same coolant pumping capacity, more coolant can flow through the cooling channel KN, thereby increasing the cooling efficiency at a low coolant temperature.At a high coolant temperature, the insert body EK expands, so that the flow area in the cooling channel KN decreases, as a result of which the flow speed and the pressure loss also increase. However, the pressure loss at high temperature is less critical and thus does not pose a problem for efficient cooling.With the insert body EK in the cooling channel KN, the pressure loss in the cooling channel KN and the overall efficiency loss of the radiator performance can thus be limited.

Claims

An electronics cooler (KL) for cooling an electronics device (EV), comprising: - a cooling channel (KN) for passing a liquid coolant through it; - a cooler part (KT) which at least partially encloses the cooling channel (KN); - an insert body (EK) which is arranged in the cooling channel (KN) and is configured to reversibly expand or shrink depending on the temperature of the coolant flowing through the cooling channel (KN) and thus to regulate or change the flow of the coolant through the cooling channel (KN); - wherein the insert body (EK) is arranged in a floating manner in the cooling channel (KN).The electronic cooler (KL) according to claim 1, wherein the insert body (EK) has a coefficient of expansion which is higher than the coefficient of expansion of the cooler part by at least 50%, or by at least 100%, or by at least 200%, or is at least five times or by at least ten times the coefficient of expansion of the cooler part.The electronic cooler (KL) according to claim 1 or 2, wherein the insert body (EK) contains silicone.The electronic cooler (KL) according to one of the preceding claims, wherein the cooler part (KT) has a section at which the insert body (EK) is not held displaceably in the longitudinal direction (LR) of the cooling duct (KN).The electronic cooler (KL) according to claim 4, wherein the cooler part (KT) has cooler pins (VS1) for increasing the cooling surface (OF1) of the cooler part (KT), one of the cooler pins (VS1) forming the portion.The electronic cooler (KL) according to any one of the preceding claims, wherein the insert body (EK) has a surface structure (VS2) for enlarging the surface of the insert body (EK).Electronic cooler (KL) according to claims 5 and 6, wherein the surface structure (VS2) of the insert body (EK) extends into the intermediate spaces (ZR) formed between the cooler pins (VS1), whereby the insert body (EK) is not held displaceably in the longitudinal direction (LR) of the cooling channel (KN).The electronic cooler (KL) according to any one of the preceding claims, wherein the insert body (EK) is shaped to change flow of the coolant in a direction transverse to the longitudinal direction (LR) of the cooling channel (KN).The electronic cooler (KL) according to one of the preceding claims, wherein - the cooling channel (KN) has two parallel channel sections; - wherein the insert body (EK) is further configured to regulate or change the flow ratio of the coolant flows of the coolant flowing through the two channel sections depending on the temperature of the coolant.The electronic cooler (KL) according to one of the preceding claims, further comprising a plurality of insert bodies (EK) with different coefficients of expansion, which are arranged one behind the other distributed in the longitudinal direction (LR) of the cooling channel (KN) at different positions in the cooling channel (KN).Electronic device (EV), comprising: - an electronic module (EM); - a cooler (KL) according to one of the preceding claims; - wherein the electronic module (EM) lies with the cooler (KL) on the cooler (KL) and is thermally contacted with the cooler (KL).Inverter, comprising: - an electronic device according to claim 11; - a driver circuit for operating the electronic module (EM), which driver circuit is connected to the electronic module (EM) via a signal connection.

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