Graphene-based thermoelectric guide module and electronics thermoelectric management system comprising it

Abstract

A graphene-based thermoelectric guide module comprising a heat source 4 generating heat and providing a heat map, and / or at least one power source supplying electric power distributed to a multitude o

Description

The present invention relates to a graphene-based thermoelectric guide module. More specifically, the invention relates to a graphene-based thermoelectric guide module integrated in an automotive electronics thermoelectric management system. The heat dissipation performance of an electronic device directly and critically determines the service life of the component itself. The heat dissipation rate is proportional to the temperature difference between the electronic device and its surroundings, and the thermal conductivity of electronic components, intermediate elements and environment. Nowadays, due to the miniaturization of electronic control units (ECUs), automotive electronics tend to become high power density electronic systems confined in small spaces; classical cooling solutions, such as remote air fans, air ducts, heat pumps etc. may not be effectively applied in narrow places. Heat generated by electronic components is dissipated with the help of thermal paste, or a metallic heat spreader, or a metallic backplate and / or other part that can be used as a heat spreader (e.g. brackets, car chassis). Nevertheless, new material technologies were developed, for example carbon-based nanostructures such as graphene. According to the article ..Thermal properties of graphene: Fundamentals and applications" [1], graphene is a two-dimensional (2D) material with over 100-fold anisotropy of heat flow between the in-plane and out-of-plane directions. Also, there were invented methods of deposing graphene thermal conductive rolls on flexible substrates (as described by Polsen, E.. McNerny, D.. Viswanath, B. et al. in the scientific report ..High-speed roll-to-roll manufacturing of graphene using a concentric tube OVD reactor11 [2], published in 21 May 2015, Scientific Reports 5, article number 10257 (2015), DOI: 10.1038 / srep10257 (2015). Patent literature also illustrates recent progress in adopting carbon-based (i.e., graphene) technologies for thermal management. In this respect, US20180177072 A1 discloses an electronics chassis assembly, including a housing with interior and exterior walls, at least one of which is a thermally conductive wall, and a graphene foil heat spreader operably coupled to a portion of the housing. WO 2016118457 A1 relates to computing devices provided with a sandwich structured composite housing, wherein thermal insulative and thermal conductive layers are interposed, and the thermal conductive layers are sheets comprising graphite, graphene or carbon nanostructures. US 20140060087 A1 refers to a heat radiation thermoelectric fin that includes a thermoelectric inorganic material on a heterogeous laminate of graphene. The heterogeneous laminate is tube-shaped or plate-shaped, and a metal conductor is coupled to one or more of the heterogeneous laminate. A thermoelectric module is formed to include the fin. However, the use of graphene-based conductive sheets is associated with some deficiencies, such as their brittleness and weak thermal coupling with substrates, which implies that interfaces and contacts remain significant dissipation bottlenecks. Therefore, the technical problem to be solved, in this context, is how to adapt the configuration of a heat guide to hot spots, while increasing the heat extracting efficiency. It is an object of the present invention to solve the prior art deficiencies and to provide a supple thermoelectric guide module, able to combine the high heat dissipation properties of carbon-based nanostructures with the flexibility and good thermal and / or electrical conductivity of a metallic core. It is another object of the present invention to provide an electronics thermoelectric management system capable of extracting heat from narrow spaces. The above-mentioned and other objects are realized by means of the technical features and characteristics mentioned in the independent claims. Further advantageous embodiments are the subject-matter of the dependent claims. According to a first aspect of the invention, there is provided a graphene-based thermoelectric guide module, comprising at least one heat source generating heat and providing a map of the generated heat, and / or at least one power source supplying power distributed to a multitude of loads and providing a power distribution map, as well as a multitude of thermoelectric guides operatively in contact, at one end, with the at least one heat source and / or power source, and oriented in out-of-plane directions relative to the respective at least one heat source and / or power source(s). The multitude of thermoelectric guides is arranged with a density varying according to the heatmap provided by the at least one heat source, and / or with sections varying according to the power distribution map provided by the at least one power source. By implementing the invention, a range of advantages are obtained: - improved combined thermal and electrical conductivity, along with an increased capability to transfer heat away from sensitive hot spots; - freedom to use non-metallic housings for heat-generating sources with increased computing power; - freedom to use various arrangements of voltage rails or temperature paths adapted to small spaces. In one embodiment of the present invention, some of the thermoelectric guides from the multitude of thermoelectric guides are operatively in contact to one or several heat spreader(s) at the other end; some of the thermoelectric guides from the multitude of thermoelectric guides are operatively in contact to one or several load(s) at the other end, according to the power distribution map. Furthermore, the thermoelectric guides are held in contact to the respective heat and / or power source or to the respective heat spreader(s) or load(s) by bonding means such as thermal paste, glue, epoxy resin or a bracket. In case the bonding means is a bracket placed at least one heat source end, the bracket is modeled as a matrix holding the multitude of thermoelectric guides with variable density in accordance to the heatmap provided by the heat source. In case the bonding means is a bracket placed at least one power source end, the bracket is modeled as a matrix holding each of the multitude of thermoelectric guides isolated in bundles, with variable sections modeled in accordance to the power distribution map provided by the power source. Moreover, at least one intermediary layer is provided at either at least one heat source end or the heat spreader end, respectively, in case a thermal connection is allowed between the thermoelectrical guides and the heat source, but not an electrical connection. For example, the intermediary layer is made of industrial diamond powder. In some embodiments, the thermoelectrical guides are round, square, rectangular or irregular in section, their respective sections being configured in dependence to the heat to be dissipated and / or the power to be supplied. According to a second aspect of the invention, there is provided an electronics thermoelectric management system comprising at least one inventive thermoelectric guide module that guides the power supplied by at least one battery to a load, namely at least one electronic control unit, and at least one electronic control unit is the heat source from which at least one thermoelectric guide module leads heat to at least one heat spreader. In one embodiment of the electronic thermoelectric management system, the electronics thermoelectric management system is adapted to a vehicle, being operatively connected to vehicle power source by means of the vehicle connector. Further aspects of the invention are described below. It will be apparent to those skilled in the art that the above features of embodiments of the graphene-based thermoelectric guide module may also be used in conjunction with the following aspects of the invention and vice versa. Figures Figure 1 shows a prior art graphene-based thermoelectric guide in various views, namely: Fig. 1a illustrates a sectional view of the graphene-based thermoelectric guide comprising a graphene laminate coating a metallic substrate, Fig. 1b shows how the graphene-based thermoelectric guide is obtained, by wrapping a metallic core with a graphene sheet, and Fig. 1c presents a longitudinal section view of the graphene-based thermoelectric guide, Fig. 2 shows some elements of the graphene-based thermoelectric guide module according to invention, Fig. 3 illustrates schematically a first embodiment of the thermoelectric guide module according to invention, comprising thermoelectric guides, a heat source and a heat spreader, Fig. 4 shows a second embodiment of the thermoelectric guide module, Fig. 5 presents a third embodiment of the thermoelectric guide module, Fig. 6 illustrates a first embodiment of an electronics thermoelectric management system, adapted to a vehicle, Fig. 7 presents a second embodiment of the electronics thermoelectric management system, Fig. 8 presents a third embodiment of the electronics thermoelectric management system. Detailed description For a better understanding of the principles of the present invention, embodiments of the invention will be explained in more detail below with reference to the figures. Like reference numerals are used in the figures for the same or equivalent elements and are not necessarily described again for each figure. Various embodiments described herein are generally directed to heat dissipation techniques related to electronics systems. In the following, an exemplary prior art graphene-based thermoelectric guide 1 is illustrated by Fig. 1; most precisely, Fig. 1 a illustrates a sectional view of the prior art thermoelectric guide 1 comprising a graphene sheet GS coating a metallic core MC. Fig. 1 b shows how such a thermoelectric guide is obtained, for example, namely by wrapping metallic core MC with several layers of graphene sheet GS. Another longitudinal section view of the obtained thermoelectric guide 1 is presented in Fig. 1c. Details of such exemplary prior art thermoelectric guides may vary in terms of shape (wire, tube or plate), section (square or irregular instead of round), core material (copper or aluminum, for example), number of coating graphene layers (50 to over 200), so on and so forth. Another example of such prior art graphene-based thermoelectric guide (not illustrated) is just a graphene roll without a metallic core; such thermoelectric guide may lack plasticity, but it is an alternative solution for extremely narrow spaces (in range of millimeters). Such a design allows also encapsulation of the module, as to be easily removed in case of need. Fig. 2 shows some of the elements of the graphene-based thermoelectric guide module according to invention. More specifically, Fig. 2 illustrates graphene-based thermoelectric guides 1 oriented in an out-of-plane direction and held together by bonding means 2 allowing thermal connection (glue, resin, thermal paste or a mechanical bracket), and furthermore by electrically isolating intermediary layer(s) 3 (e.g., industrial diamond powder mixed with thermal paste or epoxy resin, or sealed by a perimeter layer of thermal paste to keep the diamond powder close to heat source. This allows thermal expansion but prevents free movement of the abrasive particles of diamond powder, therefore grinding provoked by vibration is also mitigated). Fig. 3 presents a first embodiment of the thermoelectric guide module, wherein several thermoelectric guides 1 are joined together by bonding means 2 and electrically isolated by intermediary layers 3 to a heat source 4 at one end, and to a heat spreader 5, at the other end. In this case, the path from heat source to heat spreader is straight. Also in this case, the thermoelectric guide module is encapsulated and removable. Heat source 4 is placed upon a printed circuit board 6. All these elements are enclosed within a housing A. What makes a difference from prior art so far (and is not so evident in the accompanying drawings) is that the thermoelectric guides’ arrangement is adapted to hot spots, provided a heatmap of such hot spots is known. Usually, for every electronics design project, a feasibility assessment is performed in advance, in order to identify potential hot spots (at least) and how these hot spots may influence their environment. Such a feasibility assessment is performed by means of a heatmap - an instrument essential for this invention. Given the heatmap, parameters such as length, area, density (number per area), distribution of the multitude of graphene-based thermoelectric guides are adapted in direct dependence to the heatmap. For example, the multitude of thermoelectric guides is distributed in bundles operatively coupled to the heat source(s) by means of bonding means and intermediary layer(s), and the length, density, or section of thermoelectric guides distributed in respective bundles are adapted according to the known heatmap, and to the amount of heat to be dissipated. Also, the number of heat spreaders may vary, from just one to several of them, placed in different relative arrangements (internal or external) and made of different material (ceramic, metal etc.). In addition to the heat management, also electrical power management is addressed by the thermoelectric guide module according to invention, provided a power distribution map from a power source to one (or several) electrical load(s) is known. Such a power distribution map is also provided as a result of the feasibility assessment. Given the power distribution map, meaning the map of the power needed to be supplied to one load to another, parameters such as length, section and distribution of the multitude of graphene-based thermoelectric guides are adapted in direct dependence to the power distribution map. For example, the multitude of thermoelectric guides is distributed in bundles operatively coupled to the power source(s) by means of bonding means, each bundle comprising a number of isolated thermoelectric guides having their respective length and section adapted according to both power needed to be supplied, and heat to be dissipated. Also, the number and the type of power sources may vary, from just one to several of them, placed in different relative arrangements (internal or external), etc. Fig. 4 shows a second embodiment of the thermoelectric guide module, where the plasticity of the thermoelectric guide allows the thermoelectric guide module to be adapted to various geometries and paths from heat or power source(s) to heat spreader(s) and / or load(s). More precisely, in this case, the path from heat source to heat spreader or from power source to load is sinuous, for example the heat spreader being arranged in 90 degrees offset position from the heat source. The thermoelectric guide module is either separated from the other elements, or integrated in single unit. Fig. 5 presents a third embodiment of the thermoelectric guide module, where an external encapsulated thermoelectric guide module B is operatively coupled to the housing A and to an external heat spreader 5. Fig. 6 illustrates a first embodiment of an electronics thermoelectric management system, adapted to a vehicle schematically represented by a chassis 8, which also represent the ground (zero voltage). In essence, the electronics thermoelectric management system comprises the housing A operatively coupled with the external thermoelectric guide module B by means of fastening means 7, for example, a press fit connector. The printed circuit board 6 is coupled to the ground (zero voltage) by means of a ground connector 9, and to voltage by means of a positive lead supply connector 10. Fig. 7 illustrates a second embodiment of the electronics thermoelectric management system, comprising in addition to the components mentioned for the first embodiment split thermoelectric guide modules 1 and an external thermoelectric guide C, leading heat to a second heat spreader of different arrangement, material and heat dissipation degree. Fig. 8 presents a third embodiment of the electronics thermoelectric management system, where the housing A encloses an internal thermoelectric guide modules B and C. Printed circuit board 6 supports at least one electronic control unit 4,4’ and is connected to both positive lead and ground by means of a connector 7. Thermoelectric guide module B leads power supplied by power source 5’ (for example, a battery or a stack of fuel cells), the number, section and length of thermoelectric guides 1 of module B being designed according to the power needed to be supplied to loads 4, 4’ respectively; in this embodiment, electronic control units 4, 4’ play the role of either load 4’ for the power supplied by thermoelectric guide module B, or heat source 4 for heat to be guided by thermoelectric guide module C to heat spreader 5 or both. The multitude of graphene-based guides 1 enclosed by module B are individually coated by isolating materials, e.g., teflon, PVC, plastic, composite materials etc., and split in several bundles dedicated to each electronic control unit 4’ needed to be supplied with power. Similar design is applied to thermoelectric guides 1 enclosed by module C, in case more than one heat spreader C is used. However, while certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims. List of reference numbers A - Housing B, C - Thermoelectric guide module 5 GS - Graphene sheet MC - Metal core 1 - Thermoelectric guide 2 - Bonding means 3 - Intermediary layer 10 4-Heat source 4’ - Electrical load 5 - Heat spreader 5’ - Power source 6 - Printed circuit board 15 7 - Fastening means 8 - Chassis 9 - Ground connector 10 - Positive lead supply connector Bibliographic references Non-Patent Literature [1] Pop, E., Varshney, V. &Roy, A.K.,,Thermal properties of graphene: 5 Fundamentals and applications", MRS Bulletin 37, 1273-1281 (2012), DOI: 10.1557 / mrs.2012.203 [2] Polsen E. S., McNerny D. Q., Viswanath B., Pattinson S. W., John Hart A. „High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD 10 reactor", Sci Rep. 2015 May 21 ;5:10257, DOI: 10.1038 / srep10257 Patent Literature US20180177072 A1 WO 2016118457 A1 15 US 20140060087A1

Claims

1. A graphene-based thermoelectric guide module comprising:at least one heat source (4,4‘) generating heat and providing a map of the generated heat, and / orat least one power source (5‘) supplying power distributed to a multitude of loads (4‘) and providing a power distribution map,a multitude of thermoelectric guides (1) operatively in contact, at one end, with the at least one heat source (4) and / or power source (5’), and oriented in out-of-plane directions relative to the respective at least one heat source and / or power source, the multitude of thermoelectric guides (1) being arranged with a density varying according to the heatmap provided by the at least one heat source (4), and / or with sections varying according to the power distribution map provided by the at least one power source (5’).

2. Graphene-based thermoelectric guide module according to claim 1, characterized in that some of the thermoelectric guides (1) from the multitude of thermoelectric guides (1) are operatively in contact to one or several heat spreader(s) (5) at the other end.

3. Graphene-based thermoelectric guide module according to claim 1, characterized in that some of the thermoelectric guides (1) from the multitude of thermoelectric guides (1) are operatively in contact to one or several electric power load(s) (4’) at the other end, according to the power distribution map.

4. Graphene-based thermoelectric guide module according to claim 1, characterized in that the thermoelectric guides (1) are held in contact to the respective heat and / or power source (4, 5’) or to the respective heat spreader(s) (5) or electric power load(s) ( 4’) by bonding means (2) such as thermal paste, glue, epoxy resin or a bracket.

5. Graphene-based thermoelectric guide module according to claim 4,characterized in that, in case the bonding means (2) is a bracket placed at least one heat source (4) end, the bracket is modeled as a matrix holding the multitude of thermoelectric guides (1) with variable density in accordance to the heatmap provided by the heat source (4).

6. Graphene-based thermoelectric guide module according to claim 4, characterized in that, in case the bonding means (2) is a bracket placed at least one power source (5’) end, the bracket is modeled as a matrix holding each of the multitude of thermoelectric guides (1) electrically isolated in bundles with variable sections, modeled in accordance to the power distribution map provided by the power source (5’).

7. Graphene thermoelectric guide module according to claim 1, characterized in that at least one intermediary layer (3) is provided at either at least one heat source end or the heat spreader end, respectively, in case a thermal connection is allowed between the thermoelectrical guides (1) and the heat source (4), but not an electrical connection.

8. Graphene thermoelectric module according to claim 7, characterized in t h a t the intermediary layer (3) is made of industrial diamond powder.

9. Graphene thermoelectric module according to preceding claims, characterized in that the thermoelectrical guides (1) are round, square, rectangular or irregular in section, their respective sections being configured in dependence to the heat to be dissipated and / or the power to be supplied.

10. Electronics thermoelectric management system, characterized in that it comprises at least one thermoelectric guide module (B, C) according to claim 1, wherein the power source is a battery from which at least one thermoelectric guide module (B) supplies electric power to a load, namely at least one electronic control unit, and at least one electronic control unit is the heat source from which at least one thermoelectric guide module (C) leads heat to at least one heat spreader.

11. Vehicle incorporating an electronics thermoelectric management system according to claim 10, c h a r a ct e r i z e d in that the electronics thermoelectric management system is operatively connected to the vehicle power 5 source by means of a vehicle connector (7).

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