Use of a hydrocarbon fluid

Abstract

The invention relates to the use, in an electronic device, for example in an electric or a hybrid vehicle, of a fluid having an initial boiling point and a final boiling point in the range of from 100°C to 400°C and a boiling range below 80°C, said fluid comprising from 10 to 50%wt of isoparaffins, from 1 to 30%wt of n-paraffins and from 20 to 80%wt of naphthenes, based on the total weight of the fluid.

Description

[0001] USE OF A HYDROCARBON FLUID IN ELECTRIC VEHICLES

[0002] FIELD OF THE INVENTION

[0003] The invention relates to the use of a specific fluid for cooling and / or lubricating the motor of an electric or hybrid vehicle as well as the different parts especially the moving ones. The invention also relates to the use for lubricating these parts as well as the transmission of the vehicle.

[0004] The invention also relates to the use of a specific fluid for cooling the battery of an electric or hybrid vehicle.

[0005] BACKGROUND ART

[0006] International standards concerning CO2 emissions reduction, but also concerning the fuel efficiency of automotive engines encourage automotive constructors to develop alternative solutions to combustion engines.

[0007] Researches for reducing CO2 emission lead to the development of hybrid and electric vehicles by many automotive companies. By “electric vehicle” according to the present invention it is meant a vehicle comprising an electric motor as unique propulsion mode. By “hybrid vehicle” according to the present invention it is meant a vehicle comprising an electric motor in combination with another power source as propulsion mode. By “electric motor of a vehicle” according to the present invention it is meant the electric motor of an electric vehicle or of a hybrid vehicle.

[0008] Electric motors generate heat when operated. If the amount of generated heat is greater than what is naturally dissipated to the environment, some form of active cooling is needed. Typically, the active cooling is applied to one or more heat-generating parts of the motor, and / or the heat-sensitive part(s), so that unsafe temperatures are avoided.

[0009] Traditionally, it is known to cool electric motors by air, generally by forced convection. The air- cooling method advantageously does not require any specific coolant to be prepared. However, air is unlikely to provide a large cooling capacity, in particular regarding the downsizing of motors having higher power efficiency, rendering this cooling method unsuitable.

[0010] Nowadays it is also known to use water in order to cool electric motors. While water exhibits a high specific heat, it is not possible to consider cooling by direct contact with water because of the electrical conductivity of water. Hence, a cooling pipe has to be laid out, which disadvantageously increases the size of the cooling device.

[0011] Cooling methods of electric motors using an oil spray have also already been suggested.

[0012] For electric cars, compared to hybrid ones, there is a specific requirement for an oil with improved cooling properties since motors of electric cars are subject to more solicitations.

[0013] The electric motor is supplied by a battery. Li-ion batteries are the most common batteries in the domain of electric vehicles. The downsizing of batteries with same or improved efficiency leads to heat management problems. When the temperature of a Li-ion battery is too high there is a risk of igniting the battery or even a risk of explosion. On the other hand, when the temperature becomes too low there is a risk of unloading the battery prematurely.

[0014] An objective of the present invention is therefore to provide a fluid for cooling and / or lubricating the electric motor of an electric or hybrid vehicle.

[0015] Particularly, an objective of present invention is to provide a fluid for cooling the power electronics and / or the stator and / or the rotor and for lubricating the reducer of the electric motor of a vehicle.

[0016] Yet another objective of present invention is to provide a fluid for cooling the battery of an electric vehicle or hybrid vehicle.

[0017] SUMMARY OF THE INVENTION

[0018] The invention provides the use, in an electric or a hybrid vehicle, of a fluid having an initial boiling point and a final boiling point in the range of from 100°C to 400°C and a boiling range below 80°C, said fluid comprising from 10 to 50%wt of isoparaffins, from 1 to 30%wt of n-paraffins and from 20 to 80%wt of naphthenes, based on the total weight of the fluid.

[0019] The boiling range means the difference between the final boiling point and the initial boiling point.

[0020] According to an embodiment, the use of the invention is in an electric vehicle.

[0021] According to various embodiments, the invention relates to one or several of the following uses: for cooling the motor, for cooling the power electronics and / or the rotor and / or the stator of the motor, for cooling the battery, for lubricating the motor, for lubricating bearings between rotor and stator and / or the reducer of the motor, for lubricating the transmission, for cooling and lubricating the motor, for cooling the motor and for lubricating the transmission.

[0022] According to one embodiment, the fluid has an initial and a final boiling point in the range of from 150°C to 340°C, preferably 210°C to 290°C.

[0023] According to one embodiment, the fluid contains less than 500 ppm by weight of aromatics, preferably less than 100 ppm by weight of aromatics.

[0024] According to one embodiment, the fluid has an aniline point ranging from 50 to 100°C, preferably from 60 to 90°C. The aniline point can be measured according to ASTM D61 1 standard.

[0025] According to one embodiment, the fluid contains less than 5ppm, preferably less than 3ppm, preferably less than 1 ppm sulphur.

[0026] The fluids defined in the invention, also named “improved fluids”, due to their dual properties of cooling and lubricating will find different uses at many locations in an electric or hybrid vehicle, in particular in an electric vehicle. The vehicle, especially car, can be fully electric or hybrid. In use the improved fluids of the invention can also comprise any additive known in the art as will be disclosed below.

[0027] The improved fluid according to the invention can be used for cooling by any method known in the art. As examples of cooling method one can be a cooling by direct spraying under pressure or by spraying by gravity or by forming a mist from the improved fluids, especially on the winding of the rotor and / or stator, or by immersion.

[0028] The improved fluids provide lower risks of deterioration of seals and varnishes present in the motor, and allows avoiding any contact between water and the motor or parts thereof, such as the windings.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic representation of an electric powertrain.

[0031] DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0032] The present invention is directed to the use, in an electric or a hybrid vehicle, of a fluid having an initial boiling point and a final boiling point in the range of from 100°C to 400°C and a boiling range below 80°C, said fluid comprising from 10 to 50%wt of isoparaffins, from 1 to 30%wt of n-paraffins and from 20 to 80%wt of naphthenes, based on the total weight of the fluid.

[0033] Process for manufacturing the fluids used in the invention

[0034] The fluid used in the invention can be prepared by a specific combination of deep hydrodesulphuration process followed by hydrogenation conditions of low-sulphur, almost sulphur free feeds.

[0035] A typical feed will correspond to desulphurized atmospheric distillate comprising typically up to 30 wt% aromatics. Higher aromatics content can be processed, up to 100%. Other feeds can be possibly processed such as effluents of FCC units, for example desulphurized light cycle oil (LCO), but preferably in admixture with some atmospheric distillate after desulphuration.

[0036] A well-known feed is desulphurized atmospheric distillate with a sulphur content decreased down to less than 10 ppm by deep hydrodesulphurating using a hydrodesulphuring unit working under high pressure above 70 bars and high temperature over 300°C, preferably varying between 320 and 370°C in presence of desulphurisation catalyst in fixed bed reactor. The hydrodesulphurization catalyst comprises an alumina support with at least a couple of metals from group VIII, preferably couples of metals such as nickel / molybdene molybdenum or cobalt / molybdenum, Nickel / molybdenum being preferred. Description of such desulphurization processes and units may be found in "Procedes de transformation" from P. Leprince chapter 16 from Technip editions ISBN 2-7108-0730-0 (volume 3).

[0037] The hydrogenation feed after desulphuration typically contains less than 3ppm of sulphur, but higher amounts can be processed, for example up to 8 ppm. Lower values are preferred. There is no limit for the lower value; generally the sulphur content is at least 1 ppm. Hence, a typical low-sulphur feed will comprise 0.5 to 1 .5 ppm sulphur.

[0038] Before entering the hydrogenation unit, a prefractionation can take place. Having a more narrow boiling range entering the unit allows having a more narrow boiling range at the outlet.

[0039] The feed is then hydrogenated.

[0040] Hydrogen that is used in the hydrogenation unit is typically a high purity hydrogen, e.g. with a purity of more than 99%, albeit other grades can be used.

[0041] Hydrogenation takes place is one or more reactor. The reactor can comprise one or more catalytic beds. Catalytic beds are usually fixed beds.

[0042] Hydrogenation takes place using a catalyst. Typical hydrogenation catalysts include but are not limited to: nickel, platinum, palladium, rhenium, rhodium, nickel tungstate, nickel molybdenum, molybdenum, cobalt molybdenate, nickel molybdenate on silica and / or alumina carriers or zeolithes. A preferred catalyst is Ni-based on an alumina carrier, having a specific area varying between 100 and 250 m2 / g of catalyst, preferably between 150 and 200 m2 / g. The hydrogenation conditions are typically the following:

[0043] Pressure: 60 to 160 bars, preferably 100 to 150 bars, and most preferably 105 to 130 bars;

[0044] Temperature: 80 to 180°C, preferably 120 to 170°C and most preferably 130 to 160°C;

[0045] Liquid Hourly Space Velocity (LHSV): 0,2 to 5 hr1, preferably 0.5 to 3, and most preferably 0.8 to 1.5;

[0046] Hydrogen treat rate: 100 to 300 Nm3 / ton of feed, preferably 150 to 250 and most preferably 160 to 200.

[0047] Using high pressure, low temperature hydrogenation conditions and an effective hydrogenation Ni-containing catalyst, together with high treat rates, in contrast to the prior art, offers several advantages, in peculiar no cracking occurs. Substantially no hydrodesulphurisation takes place: the traces of remaining sulphur compounds are rather trapped into or onto the catalyst rather than being discharged as H2S in the prior art process.

[0048] The process of the invention can be carried out in several stages. There can be two or three stages, preferably three stages. The first stage will operate the sulphur trapping, hydrogenation of substantially all unsaturated, and up to about 90% of hydrogenation of aromatics. The flow exiting from the first reactor contains substantially no sulphur. In the second stage the hydrogenation of the aromatics continues, and up to 99% of aromatics are hydrogenated. The third stage is a finishing stage, allowing aromatics contents as low as 100 ppm or even less such as below 50ppm or even below 30ppm, even for high boiling products.

[0049] The catalysts can be present in varying or substantially equal amounts in each reactor, e.g. for three reactors according to weight amounts of 0.05- 0.5 / 0.10-0.70 / 0.25-0.85, preferably 0.07- 0.25 / 0.15-0.35 / 0.4-0.78 and most preferably 0.10-0.20 / 0.20- 0.32 / 0.48-0.70. It is also possible to have two reactors instead of three.

[0050] It is also possible to have two reactors instead of three.

[0051] The first stage will operate the sulphur trapping, hydrogenation of substantially all unsaturated compounds, and up to about 90% of hydrogenation of aromatics. The flow exiting from the first reactor contains substantially no sulphur. In the second stage the hydrogenation of the aromatics continues, and more than 99% of aromatics are hydrogenated, preferably allowing aromatics contents as low as 100ppm or even less such as below 50ppm or even below 30ppm, even for high boiling products.

[0052] The catalysts can be present in varying or substantially equal amounts in each reactor, e.g. for two reactors according to weight amounts of 0.05-0.5 / 0.5- 0.95, preferably 0.07-0.4 / 0.6-0.93 and most preferably 0.10-0.20 / 0.80-0.90.

[0053] It is also possible that the first reactor be made of twin reactors operated alternatively in a swing mode. This made be useful for catalyst charging and discharging: since the first reactor comprises the catalyst that is poisoned first (substantially all the sulphur is trapped in and / or on the catalyst) it should be changed often.

[0054] One reactor can used, in which two, three or more catalytic beds are installed.

[0055] It may be necessary to insert quenches on the recycle to cool effluents between the reactors or catalytic beds to control reaction temperatures and consequently hydrothermal equilibrium of the hydrogenation reaction. In a preferred embodiment, there is no necessity for such cooling or quenching.

[0056] In case the process makes use of 2 or 3 reactors, the first reactor will act as a sulphur trap, as already indicated especially for benzo and di benzothiophens and their derivatives considered as the most refractory compounds to the deep hydrodesulphurisation. This first reactor will trap substantially all the sulphur. The catalyst will thus be saturated very quickly and may be renewed from time to time; when regeneration or rejuvenation is not possible for such saturated catalyst, the first reactor is considered as a sacrificial reactor which size and catalyst content depends on catalyst renewal frequency.

[0057] In an embodiment the resulting product and / or separated gas is / are partly recycled to the inlet of the hydrogenation stages. This dilution helps maintaining the exothermicity of the reaction within controlled limits, especially at the first stage. Recycling also allows heat-exchange before the reaction and also a better control of the temperature.

[0058] The stream exiting the hydrogenation unit contains the hydrogenated product and hydrogen. Flash separators are used to separate effluents into gas, mainly remaining hydrogen, and liquids, mainly hydrogenated hydrocarbons. The process can be carried out using three flash separators, one of high pressure, one of medium pressure, and one of low pressure, very close to atmospheric pressure.

[0059] The hydrogen gas that is collected on top of the flash separators can be recycled to the inlet of the hydrogenation unit or at different levels in the hydrogenation units between the reactors.

[0060] Because the final separated product is at about atmospheric pressure, it is possible to feed directly the fractionation stage, which is preferably carried out under vacuum pressure that is at about between 10 to 50 mbars, preferably about 30 mbars.

[0061] The fractionation stage can be operated such that various hydrocarbon fluids can be withdrawn simultaneously from the fractionation column, and the boiling range of which can be predetermined. The hydrogenation reactors, the separators and the fractionation unit can thus be connected directly, without having to use intermediate tanks, as is usually the case in the prior art documents. By adapting the feed, especially the initial and final boiling points of the feed, it is possible to produce directly, without intermediate storage tanks, the final products with the desired initial and final boiling points. Moreover, this integration of hydrogenation and fractionation allows an optimized thermal integration with reduced number of equipment and energy savings.

[0062] The hydrodesulphurisation unit operates typically at a pressure higher than 70 bars, preferably higher than 85 bars. Such units can comprise two reactors and working at temperatures between 330 and 360°C, the treat ratio hydrogen to feed at the inlet being for example 100Nm3 / m3and LHSV varying from 0.5 to 3 h-1. The unit typically comprises a flash separator and a recycle conduit for recovered separated hydrogen gas. Further, hydrodesulphurised product can be stripped in a stripper unit, into naphta, and a hydrotreated middle distillate thus recovered is sent to the hydrogenation unit, as reacting feed.

[0063] The hydrogenation unit can comprise three reactors 11 , connected in series. The reacting feed enters the first reactor, and will pass then the second and eventually third reactor. The reacted stream exists the third reactor. It is possible to have part of the reacted product recycled to the inlet of the hydrogenation reactors. The reacted product then enters high pressure separator to obtain a product. Said product can be divided into two lines, a first line containing a recycled stream and a second line containing the target product (stream exiting the hydrogenation section). The recycled stream still comprises hydrogen. This is combined with the source of hydrogen and feed. A heat exchanger 6 is used to adjust the temperature of the mixture entering the hydrogenation unit.

[0064] The temperature in the reactors is typically about 150-160°C and the pressure is typically about 140 bars while the hourly space velocity is typically about 0.8 and the treat rate is typically about 100 to 180 Nm3 / ton of feed, depending on the feed quality. The stream exiting the hydrogenation section will enter the first flash separator, the stream out of the first separator is partly recycled and partly sent to the second separator. This recycle ratio is between 2 and 20 typically about 4 to about 5.

[0065] The first flash separator is a high pressure separator, operated at a pressure ranging e.g. from about 60 to about 160 bars, preferably from about 100 to about 150 bars, and especially at about 100- 120 bars.

[0066] The second flash separator is a medium pressure separator, operated at a pressure ranging e.g. from about 10 to about 40 bars, preferably from about 20 to about 30 bars, and especially at about 27 bars.

[0067] Then a third, low pressure flash separator is used. This third separator is preferably operated at a pressure ranging e.g. from about 0.5 to 5 bars, preferably from about 0.8 to about 2 bars, and especially at about atmospheric pressure. A flow of product free of hydrogen is withdrawn and sent directly to the fractionation column.

[0068] The fractionation column is preferably operated under vacuum pressure, such as about 30mbars absolute. The temperature profile of the column is set depending on the boiling properties of the products to be recovered. Different streams can be withdrawn from top to bottom of the column, including at lateral, intermediate levels.

[0069] The final products are then sent to storage.

[0070] Fluid used in the invention

[0071] The fluid of the invention has an initial boiling point and a final boiling point in the range of from 100°C to 400°C, preferably from 150°C to 340°C, preferably from 210 to 290°C.

[0072] The fluid of the invention has a boiling range below 80°C, preferably from 5 to 70°C, preferably from 10 to 60°C.

[0073] The boiling point and boiling range of the fluid can be measured according to ASTM D86.

[0074] The fluid of the invention comprises from 10 to 50%wt of isoparaffins, preferably from 20 to 40%wt of isoparaffins, based on the total weight of the fluid.

[0075] The fluid of the invention comprises from 1 to 30%wt of n-paraffins, preferably from 5 to 20%wt of n-paraffines, based on the total weight of the fluid.

[0076] The fluid of the invention comprises from 20 to 80%wt of naphthenes, preferably from 30 to 60%wt of naphthenes, based on the total weight of the fluid.

[0077] According to a particular embodiment, the fluid of the invention can comprise less than 10%wt of mononaphthenes, from 5 to 40%wt of di-naphthenes, less than 10%wt of tri-naphthenes and from 5 to 55%wt of iso-naphthenes, based on the total weight of the fluid.

[0078] According to an embodiment, the weight ratio isoparaffins / naphthenes in the fluid used in the invention ranges from 0.1 to 2, preferably from 0.2 to 1 . According to an embodiment, the weight ratio n-paraffins / naphthenes in the fluid used in the invention ranges from 0.01 to 1 , preferably from 0.05 to 0.7.

[0079] According to an embodiment, the weight ratio n-paraffins / isoparaffins in the fluid used in the invention ranges from 0.02 to 1 , preferably from 0.05 to 0.9.

[0080] The inventors found that a fluid having these compositions have particularly good properties for cooling and lubricating mechanical parts of hybrid or electric vehicles.

[0081] Within the meaning of the present invention, “isoparaffins” refers to aliphatic saturated and branched (non-cyclic) hydrocarbons consisting of carbon atoms and hydrogen atoms.

[0082] Within the meaning of the present invention, “n-paraffins” refers to aliphatic saturated and linear (non cyclic) hydrocarbons consisting of carbon atoms and hydrogen atoms.

[0083] Within the meaning of the present invention, “naphthenes” refers to aliphatic saturated and cyclic hydrocarbons consisting of carbon atoms and hydrogen atoms. The cycles can be monocycles or polycycles and they can be branched by alkyl groups. As non-limiting examples, naphthenes can be mono-naphthenes, di-naphthenes, tri-naphthenes and / or iso-naphthenes.

[0084] Within the meaning of the present invention, “iso-naphthenes” refers to branched naphthenes. Iso-naphthenes can be monocyclic or polycyclic.

[0085] Within the meaning of the present invention, “mono-naphthenes”, “di-naphthenes” and “trinaphthenes” refer to naphthenes that are not branched.

[0086] Within the meaning of the present invention, “olefins” refers to aliphatic unsaturated linear or branched hydrocarbons consisting of carbon atoms and hydrogen atoms.

[0087] Within the meaning of the present invention, “aromatics” refers to compounds comprising at least one aromatic ring.

[0088] According to an embodiment, the fluid of the invention comprises less than 500 ppm by weight of aromatics, preferably less than 100 ppm by weight of aromatics.

[0089] According to an embodiment, the fluid of the invention comprises less than 5ppm, even less than 3ppm and preferably less than 1 ppm sulphur. The amount of sulphur can be measured according to ASTM D5453.

[0090] The amounts of isoparaffins, n-paraffins, naphthenes can be measured by gas chromatography according to well known methods for the skilled person.

[0091] The amounts of aromatics can be measured by UV method.

[0092] According to an embodiment, the fluid of the invention has an aniline point ranging from 50 to 100°C, preferably from 60 to 90°C. According to an embodiment, the fluid of the invention has a flash point ranging from 60 to 200°C, preferably from 60 to 120°C. The flash point can be measured according to ASTM D92 within the context of the present invention.

[0093] According to an embodiment, the fluid of the invention has a pour point of less than -20°C, preferably less than -40°C. The pour point can be measured according to ASTM D97.

[0094] According to an embodiment, the fluid of the invention has an auto-inflammation temperature of at least 190°C, preferably at least 210°C. The auto-inflammation temperature can be measured according to ASTM E659.

[0095] Advantageously, the fluid of the invention is readily biodegradable according to OECD 301 / 306.

[0096] According to a particularly preferred embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 100°C to 400°C and a boiling range below 80%, and comprises: from 10 to 50%wt of isoparaffins, from 5 to 20%wt of n-paraffines, from 20 to 80%wt of naphthenes, based on the total weight of the fluid.

[0097] According to a particularly preferred embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 100°C to 400°C and a boiling range below 80%, and comprises: from 10 to 50%wt of isoparaffins, from 5 to 20%wt of n-paraffines, from 20 to 80%wt of naphthenes, less than 500 ppm of aromatics, based on the total weight of the fluid.

[0098] According to a particularly preferred embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 210°C to 290°C and a boiling range below 80%, and comprises: from 10 to 50%wt of isoparaffins, from 1 to 30%wt of n-paraffines, from 20 to 80%wt of naphthenes, based on the total weight of the fluid. According to a particularly preferred embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 150°C to 340°C, a boiling range from 5 to 70°C, and comprises: from 20 to 40%wt of isoparaffins, from 5 to 20%wt of n-paraffines, from 30 to 60%wt of naphthenes, less than 100 ppm of aromatics, based on the total weight of the fluid.

[0099] According to a particularly preferred embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 150°C to 340°C, a boiling range from 5 to 70°C, and comprises: from 20 to 40%wt of isoparaffins, from 5 to 20%wt of n-paraffines, from 30 to 60%wt of naphthenes, less than 100 ppm of aromatics, based on the total weight of the fluid, wherein the flash point of the fluid ranges from 60 to 120°C.

[0100] According to a particular embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 150°C to 340°C, a boiling range from 5 to 70°C, and comprises: from 20 to 40%wt of isoparaffins, from 5 to 20%wt of n-paraffines, less than 10%wt of mononaphthenes, 5 to 40%wt of di-naphthenes, less than 10%wt of tri-naphthenes 5 to 55%wt of iso-naphthenes, less than 100 ppm of aromatics, based on the total weight of the fluid.

[0101] According to a particular embodiment, the fluid used in the invention has an initial boiling point and a final boiling point in the range from 150°C to 340°C, a boiling range from 5 to 70°C, and comprises: from 20 to 40%wt of isoparaffins, from 5 to 20%wt of n-paraffines, less than 10%wt of mononaphthenes, 5 to 40%wt of di-naphthenes, less than 10%wt of tri-naphthenes 5 to 55%wt of iso-naphthenes, less than 100 ppm of aromatics, based on the total weight of the fluid, wherein the flash point of the fluid ranges from 60 to 120°C.

[0102] Lubricating composition

[0103] When used as lubricant, the fluids are typically in a lubricating composition, wherein the fluid defined in the invention can represent from 1 to 100% by weight relative to the total weight of the composition.

[0104] The fluid of the invention can be the unique base oil or can be used as a co-base, i.e. in mixture with one or more other base oils,

[0105] The other base oil(s) can be of mineral or renewable origin, especially chosen among group I to V base oils according to API classification, preferably the other base oil is chosen among groups III or IV base oils according to API classification, more preferably the other base oil is chosen among groups III or IV base oils, according to API classification, having a kinematic viscosity at 100°C ranging from 1 to 10 cSt, even more preferably the other base oil is selected from polyalphaolefins having a kinematic viscosity at 100°C ranging from 2 to 6 cSt.

[0106] In an embodiment, the lubricating composition comprises from 1 to 99%wt of the fluid defined in the invention, relative to the total weight of the composition.

[0107] In a particular embodiment, the lubricating composition comprises 50 to 99%wt, preferably 70 to 99%wt, preferably 80 to 99%wt, of the fluid defined in the invention, relative to the total weight of the composition; this embodiment may correspond to the use of the fluid of the invention as a majority or sole base oil in the lubricating composition.

[0108] In another particular embodiment, the lubricating composition can comprise from 1 to 40%wt, preferably from 5 to 30%wt, more preferably from 10 to 30%wt, of the fluid defined in the invention, relative to the total weight of the composition; this embodiment may correspond to the use of the fluid of the invention as an additional base oil (or co-base oil) in the lubricating composition. The main base oil is standard and can be of mineral or renewable origin, especially chosen among group I to V base oils according to API classification.

[0109] In another embodiment the fluids may be used in combination with other lubricating compositions.

[0110] The lubricating composition according to the present invention may further comprise an additive selected from selected friction modifiers, detergents, antiwear additives, extreme pressure additives, viscosity improvers index, dispersants, antioxidants the pour point improvers, antifoams, thickeners and mixtures thereof.

[0111] Anti-wear additives and extreme pressure additives protect the formation by rubbing surfaces of a protective film adsorbed on these surfaces. There are a wide variety of anti-wear additives. Preferably the anti-wear additives are selected from phospho-sulfurized additives such as metal alkylthiophosphates, especially zinc alkylthiophosphates, more specifically the zinc dialkyl dithiophosphates or ZnDTP. Preferred compounds are of the formula Zn((SP(S)(OR2)(OR3))2, wherein R2 and R3, identical or different, independently represent an alkyl group, preferably an alkyl group having 1 to 18 carbon atoms .

[0112] Phosphates amines are also anti-wear additives that can be employed in the lubricating composition according to the invention. However, phosphorus provided by these additives can act as poison for automobile catalytic systems because these additives are generators of ashes. One can minimize these effects by partially substituting the amine phosphate by additives bringing no phosphorus, such as, for example, polysulfides, including sulfurized olefins.

[0113] Advantageously, the lubricating composition according to the invention may comprise from 0.01 to 6% by weight, preferably from 0.05 to 4% by mass, more preferably from 0.1 to 2% by mass relative to the mass total lubricant composition, of anti-wear and extreme pressure additives additives.

[0114] Advantageously, the lubricating composition according to the invention may comprise at least one friction modifier additive. The friction modifier additive can be selected from a compound supplying metal elements and a free compound of ashes. Among the compounds providing the metallic elements some include transition metal complexes such as Mo, Sb, Sn, Fe, Cu, Zn whose ligands can be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus. The ashless friction modifier additives are usually organic in origin and may be selected from monoesters of fatty acids and of polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borated fatty epoxides; fatty amines or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group having from 10 to 24 carbon atoms.

[0115] Advantageously, the lubricating composition of the invention may comprise from 0.01 to 2% by weight or 0.01 to 5% by weight, preferably from 0.1 to 1 .5% by mass or 0.1 to 2% by weight based on the total weight of the lubricating composition, of a friction modifier additive.

[0116] Advantageously, the lubricating composition according to the invention may comprise at least one antioxidant additive.

[0117] The antioxidant additive generally used to delay the degradation of the lubricating composition in service. This degradation may in particular result in the formation of deposits, the presence of sludge, or a viscosity increase of the lubricating composition.

[0118] The additives including antioxidants act as free radical inhibitors or destructive hydroperoxides. Among the additives commonly used antioxidants include phenolic antioxidants additives type additives amine type antioxidants, antioxidants additives phosphorosulphur. Some of these antioxidant additives, for example antioxidants phosphorosulphur additives may be ash generators. Additives phenolic antioxidants may be ashless or be in the form of neutral or basic metal salts. The antioxidant additives may be chosen from sterically hindered phenols, sterically hindered phenol esters and hindered phenols comprising a thioether bridge, the diphenylamines, the substituted diphenylamines at least one alkyl group C1-C12, N, N '-dialky le-ary I diamines and mixtures thereof. Preferably according to the invention, sterically hindered phenols are selected from compounds comprising a phenol group having at least one vicinal carbon atoms bearing the alcohol function is substituted by at least one C1-C10 alkyl group, preferably an alkyl group C1-C6, preferably a C4 alkyl group, preferably tert-butyl group.

[0119] Amine compounds are another class of antioxidant additives that can be used, optionally in combination with additives phenolic antioxidants. Examples of amino compounds are aromatic amines, for example, aromatic amines of the formula NR4R5R6 wherein R4 represents an aliphatic group or an aromatic group, optionally substituted, R5 represents an aromatic group optionally substituted, R6 represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R7S(O)zR8 in which R7 represents an alkylene group or an alkenylene group, R8 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2 .

[0120] Sulfurized alkyl phenols or their alkali and alkaline earth metal salts may also be used as antioxidant additives.

[0121] Another antioxidant additives class is that of copper compounds, for examples thio- or dithiophosphates of copper, copper salts and of carboxylic acids, dithiocarbamates, sulphonates, phenates, copper acetylacetonates. Copper salts I and II, the acid salts or succinic anhydride can also be used.

[0122] The lubricating composition according to the invention can contain all types of antioxidant additives known to the skilled person.

[0123] Advantageously, the lubricating composition comprises at least one antioxidant ashless additive.

[0124] Also advantageously, the lubricating composition according to the invention comprises from 0.5 to 2% by weight relative to the total weight of the composition, of at least one antioxidant additive.

[0125] The lubricating composition according to the invention may further comprise at least one detergent additive.

[0126] The detergent additives generally reduce the formation of deposits on the surface of metal parts by dissolution of secondary oxidation and combustion products.

[0127] The detergent additives used in the lubricating composition according to the invention are generally known to those skilled in the art. The detergent additives can be anionic compounds comprising a lipophilic long hydrocarbon chain and a hydrophilic head. The associated cation may be a metal cation of an alkali metal or alkaline earth metal.

[0128] The detergent additives are preferably selected from alkali metal salts or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and the salts. Alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

[0129] These metal salts generally include the metal in stoichiometric amount or in excess, that is an amount higher than the stoichiometric amount. The additives are then overbased detergents; excess metal providing the character to the overbased detergent additive being usually in the form of an insoluble metal salt in the oil, for example a carbonate, hydroxide, oxalate, acetate, glutamate, preferably a carbonate. Advantageously, the lubricating composition of the invention may comprise from 2 to 4% by weight of detergent additive based on the total weight of the lubricating composition.

[0130] The lubricating composition of the invention may also comprise at least a pour point depressant additive, albeit this is generally not needed given the pour point of the improved fluids.

[0131] By slowing down the formation of wax crystals, pour point depressant additives generally improve the temperature behavior of the lubricant composition according to the invention.

[0132] As examples of additives pour point depressants include alkyl polymethacrylates, poly acrylates, polyarylamides, the polyalkylphenols, the polyalkylnaphthalenes, alkylated polystyrenes.

[0133] Advantageously, the lubricating composition according to the invention may also comprise at least one dispersing agent.

[0134] The dispersing agent may be selected from Mannich bases, succinimides and derivatives thereof.

[0135] Also advantageously, the lubricating composition according to the invention may comprise from 0.2 to 10% by weight of dispersing agent relative to the total weight of the lubricating composition.

[0136] The lubricating composition of the present invention may further comprise at least one additive improving viscosity index. Examples of additives which improve the viscosity index, there may be mentioned ester polymers, homopolymers or copolymers, hydrogenated or non-hydrogenated, styrene, butadiene and isoprene, polyacrylates, polymethacrylates (PMA) or the olefin copolymers, particularly ethylene / propylene copolymers.

[0137] The lubricating composition of the invention can be in various forms. The lubricating composition according to the invention may especially not be an emulsion and is more preferably an anhydrous composition.

[0138] Electronic device:

[0139] The invention relates to the use of the fluid as defined here above to cool and / or to lubricate at least one electronic device.

[0140] Preferably, in the present invention, the electronic device(s) is (are) selected from hybrid or electric vehicle devices, energy storage devices, photovoltaic panels, cables (e.g., charging cables), high-power chargers, data centers, high-performance computing devices, electric charging stations, stationary electricity storage devices, transformers, concentrated solar power devices, heat storage devices, antennas (such as 5G antennas), medical devices, switching devices, chargers, computers, aeronautical electronics, computer electronics, inverters, rectifiers, converters (e.g., DC / DC, AC / AC, DC / AC, or AC / DC converters), and electric motor controllers, more preferably from electronic devise of hybrid or electric vehicle, such as the propulsion system, said propulsion system comprising at least an electric motor, a battery and a transmission, even more preferably from electric vehicle electronic devices. According to one embodiment, the composition defined in the invention may be used both to cool and to lubricate at least one electronic device.

[0141] The present invention also relates to a method for cooling at least one electronic device, said method comprising at least one step of contacting the fluid as defined here above with said electronic device. Typically, said electronic device will be in operation, during which it may heat up. Said fluid can then be used to cool said electronic device during the cooling method according to the invention.

[0142] According to an embodiment, the cooling method may also be a method for cooling and lubricating at least one electronic device. This embodiment may be advantageous when the electronic device is a component of a propulsion system of an electric or hybrid vehicle.

[0143] In the context of the cooling method according to the invention, the contact between the fluid and the electronic device(s) may consist of immersion or partial immersion of said electronic device(s) in said fluid, or alternatively of injection of said fluid onto the surface of said electronic device(s).

[0144] By “immersion” is meant that the entire electronic device is immerged in the fluid as defined here above. By “partial immersion” is meant that only part of the electronic device is in contact with said fluid.

[0145] The cooling can be carried out using any method known to those skilled in the art. The electronic device may be immersed or partially immersed, either statically or in circulation, in said fluid. Examples of direct contact methods include cooling by injection, jet, spraying, immersion or partial immersion in a bath, or by forming a mist from the fluid under pressure and allowing it to fall onto the electronic device by gravity.

[0146] Advantageously, the fluid as defined here above is injected in the form of a relatively high- pressure jet into the areas of the electronic device to be cooled, such as the propulsion system. Advantageously, the shear resulting from this injection reduces the fluid viscosity at the injection zone, compared to the kinematic viscosity at rest, thus further enhancing the fluid’s cooling potential.

[0147] Moreover, conventional oil circulation systems used in electric motors can also be employed, such as those described, for example, in document WO 2015 / 116496.

[0148] Figure 1 shows a schematic representation of the electric motorization in an electric or a hybrid vehicle.

[0149] The electric motor 1 of electric vehicles and hybrid vehicles comprises a power electronics 11 , connected to a stator 13 and a rotor 14. The rotating speed of the rotor is very high and this implies to add a reducer 3 between the rotor of the electric motor 1 and the wheels of the car.

[0150] The stator comprises different windings, in particular copper windings, which are alternatively supplied with electric current. This induces a rotating magnetic field. The rotor comprises itself windings, permanent magnets or the like, thus the rotating magnetic field leads to the rotation of the rotor.

[0151] The power electronics, the stator and rotor of an electric motor are typically of complex surfaces and structures all of which generating a significant amount of heat during operation. This is why the improved fluid as described hereabove is specifically used for cooling the power electronics and / or the rotor and / or the stator of the electric motor.

[0152] In a preferred embodiment the invention relates to the use of the improved fluid as defined here above for cooling the power electronics, the rotor and the stator of the electric motor.

[0153] Bearings 12 are also provided between the rotor and the stator and allow maintaining the rotation axis. These bearings are subjected to high frictional shear and rise wear issues and short lifetime problems. This is why the improved fluid as described hereabove is specifically used for lubricating bearings of the electric motor.

[0154] In a preferred embodiment the invention relates to the use of a fluid as defined hereabove for lubricating the bearings located between the rotor and the stator of the electric motor of a vehicle.

[0155] The reducer 3 aims at reducing the rotation speed at the electric motor output and thus to adapt the rotating speed transmitted to the wheels, whereby the vehicle speed can be adjusted. The reducer is submitted to high frictional constraints and requires suitable lubrication so as to avoid damaging. This is why the improved fluid as described here above is specifically used for lubricating the transmission, especially the reducer of an electric vehicle.

[0156] The invention also relates to the use of an improved fluid as defined here above for cooling the power electronics and / or the rotor and / or the stator and for lubricating the reducer and / or the bearings located between the rotor and the stator of the motor of an electric vehicle.

[0157] The invention also relates to the use of the improved fluid as defined here above for cooling the battery of a vehicle and / or the electric motor of a vehicle.

[0158] Batteries:

[0159] The invention also relates to the use of the improved fluid as defined here above for cooling the battery of a vehicle.

[0160] The electric motor is supplied by an electric battery 2. The Li-ion batteries are the most common in the domain of electric vehicles. The development of batteries being more and more powerful and with a size lesser and lesser creates issues with the cooling of the batteries. Indeed, as the temperature exceeds approximately 50 to 55°C, an important risk of ignition or even of explosion appears. On the contrary, when the temperature of these batteries falls below approximately 20 to 25°C, there is a risk of unloading the battery prematurely. There is thus a need to maintain the temperature of the battery at an acceptable temperature level.

[0161] The vehicle can be purely electric or can be hybrid and the invention equally applies to both.

[0162] Examples of suitable batteries for the propulsion systems of electric or hybrid vehicles include, in particular, lithium-ion batteries and nickel-cadmium batteries. The present invention also relates to the use of the improved fluid as defined here above to cool the battery of an electric or hybrid vehicle. In particular, said fluid is intended to be brought into direct contact with the battery.

[0163] The present invention also relates to a cooling method comprising at least one step of contacting a battery, such as a lithium-ion or nickel-cadmium battery, with a fluid as defined here above.

[0164] The contact between the improved fluid as defined here above and the battery may consist of immersing or partially immersing the battery in said fluid, or alternatively injecting said fluid onto the surface of the battery.

[0165] Electric motor:

[0166] The invention also relates to the use of the improved fluid as defined here above for cooling the electric motor of the vehicle.

[0167] The invention also relates to the method for cooling the electric motor of a vehicle comprising at least a step of contacting a mechanical part of the motor with a fluid as defined here above.

[0168] More particularly, the present invention relates to a method for cooling at least one component of a propulsion system of an electric or hybrid vehicle, said method comprising at least one step of contacting the fluid as defined here above with at least one mechanical part of the motor of an electric or hybrid vehicle.

[0169] According to this embodiment, the contact between the fluid as defined here above and the mechanical part(s) of an electric or hybrid vehicle may consist of immersing or partially immersing said part(s) in said fluid, or alternatively injecting said fluid onto the surface of said part(s) of the electric motor of an electric or hybrid vehicle.

[0170] Preferably, the cooling method involves contacting the fluid as defined here above with the electric motor comprising the rotor-stator assembly, the power electronics (dedicated to speed regulation), and the transmission of said electric motor of an electric or hybrid vehicle, preferably an electric vehicle.

[0171] The present invention also relates to the method for cooling the battery and the electric motor comprising at least a step of contacting the battery and a mechanical part of the motor with a fluid as defined here above.

[0172] The invention also relates to the method for cooling the battery and the electric motor comprising at least a step of contacting the battery and a mechanical part of the motor with a fluid as defined here above

[0173] The invention also relates to the method for cooling the power electronics and / or the rotor and / or the stator of a vehicle comprising at least a step of contacting the power electronics and / or the rotor and / or the stator with an improved fluid as defined here above.

[0174] The cooling may be performed by direct contact between the element to be cooled and the fluid of the invention (or the lubricating composition of the invention). The direct contact can be obtained by spraying the fluid onto the at least one element or by totally or partially immersing the at least one element to be cooled in a bath containing the fluid.

[0175] Examples of direct contact include cooling by injection jetting, spraying or misting the fluid under pressure and gravity onto the element to be cooled.

[0176] Advantageously, the fluid is injected by jet under fairly high pressure into the areas of the element(s) to be cooled. Advantageously, the shear resulting from this injection reduces the fluid viscosity at the injection zone, compared to the kinematic viscosity at rest, thus further enhancing the fluid’s cooling potential.

[0177] Semi-immersion or partial immersion mean that only a part of the element is immerged in the fluid. Immersion or total immersion mean that all the element is immerged in the fluid.

[0178] All features and embodiments defined in the context of the use also apply to the cooling method according to the invention. In particular, the fluid as defined here above, used in the cooling method according to the invention is as defined in the context of the use according to the invention.

[0179] The invention also relates to the method for lubricating the electric motor of a vehicle comprising at least a step of contacting a mechanical part of the motor with a fluid as defined here above.

[0180] The invention also relates to the method for lubricating the bearings located between the rotor and the stator of a vehicle comprising at least a step of contacting a mechanical part of said bearings with an improved fluid as defined here above.

[0181] The invention also relates to the method for cooling and lubricating the electric motor of a vehicle comprising at least a step of contacting a mechanical part of the motor with a fluid as defined here above.

[0182] The invention also relates to the use of the fluid as defined here above for lubricating the transmission of an electric or hybrid vehicle comprising at least a step of contacting the transmission with said fluid, preferably an electric vehicle

[0183] The invention also relates to the method for cooling the electric motor and lubricating the transmission of a vehicle comprising at least a step of contacting a mechanical part of the motor and of the transmission with a fluid as defined here above.

[0184] The invention also relates to the method for cooling the power electronics and / or the stator and / or the rotor and for lubricating the reducer and / or the bearings located between the rotor and the stator of the electric motor of a vehicle comprising at least a step of contacting a part of the power electronics and / or the stator and / or the rotor and of the reducer and / or the bearings with a fluid as defined here above.

[0185] The fluid of the invention notably exhibits particularly satisfactory electrical insulation properties for use in electric or hybrid vehicles.

[0186] The following example illustrates the invention without limiting it. EXAMPLES

[0187] A fluid as defined in the invention has been prepared and tested for their lubricant and thermal properties.

[0188] The fluid tested in the non-limiting example had been obtained by the following process.

[0189] A light distillate obtained from atmospheric distillation having an initial boiling of around 180°C and a final boiling point of around 300°C has been desulphurized on a nickel / molybdenum on alumina support catalyst under a pressure of about 88 bars at about 330-360° C at a LHSV of 2 h-1to obtain an intermediate product with the following features: density: 0.830 sulphur content: 0.5 ppm, aromatic content: 21 .9% wt.

[0190] The desulphurized light distillate has been further hydrogenated to remove aromatic compounds in the presence of a nickel hydrogenating catalyst according to the invention under a pressure of about 105 bars, at a LHSV of 1 h-1and at about 155-160°C. Then the resulting hydrogenating desulphurized distillate is fractionated. One of the cuts obtained at the end of the fractionation is detailed below.

[0191] The fluid (cut) tested in the example has an initial boiling point of about 235°C and a final boiling point of about 261 °C and comprises, based on the total weight of the fluid: around 10-15%wt of n-paraffins, around 30-40%wt of isoparaffins, around 45-55%wt of naphthenes, less than 20 ppm by weight of aromatics, less than 1 ppm of sulfur.

[0192] The fluid has an aniline point (ASTM D61 1) of about 78°C, a flash point (ASTM D92) of 104°C, a pour point (ASTM D97) of -51 °C and an auto-inflammation temperature of 218°C.

[0193] The properties of the fluid are detailed in Tables 1 and 2 below.

[0194] Table 1

[0195] Table 2

[0196] As shown in Tables 1 and 2, the fluid of the invention has very good lubricating properties and thermal properties to make it particularly suitable for lubricating and cooling the powertrain elements of an electric or hybrid vehicle, such as the power electronics, the stator, the rotor and / or the battery. The transmission of such vehicles can also be suitably lubricated thanks to the fluid of the invention.

Claims

CLAIMS1. Use of a fluid to cool and / or lubricate at least one electronic device, said fluid having an initial boiling point and a final boiling point in the range of from 100°C to 400°C and a boiling range below 80°C, said fluid comprising from 10 to 50%wt of isoparaffins, from 1 to 30%wt of n- paraffins and from 20 to 80%wt of naphthenes, based on the total weight of the fluid.

2. Use according to claim 1 , wherein said electronic device(s) are selected from hybrid or electric vehicle electronic devices, photovoltaic panels, cables, high-power chargers, data centers, high- performance computing devices, electric charging stations, stationary electricity storage devices, transformers, concentrated solar power devices, heat storage devices, antennas, medical devices, switching devices, chargers, computers, aeronautical electronics, computer electronics, inverters, rectifiers, converters, and electric motor controllers.

3. Use according to claim 1 or 2, wherein said electronic device(s) are selected from hybrid or electric vehicle electronic devices, such as the propulsion system, said propulsion system comprising at least an electric motor, a battery and a transmission, preferably said electronic device(s) are being selected from electric vehicle electronic devices.

4. Use according to claim 3, for cooling the motor.

5. Use according to claim 3 or 4, for lubricating the motor.

6. Use according to any one of claims 3 to 5, for cooling and lubricating the motor.

7. Use according to any one of claims 3 to 6, for cooling the power electronics and / or the rotor and / or the stator of the motor.

8. Use according to any one of claims 3 to 7, for lubricating bearings between rotor and stator and / or the reducer of the motor.

9. Use according to any one of claims 3 to 8, for cooling the battery.

10. Use according to any one of claims 3 to 9, for lubricating the transmission.

11. Use according to any one of claims 1 to 10, wherein the fluid has an initial boiling point and a final boiling point in the range from 150°C to 340°C, preferably 210°C to 290°C and / or wherein the boiling range of the fluid is from 5 to 70°C, preferably from 10 to 60°C.

12. Use according to any one of claims 1 to 11 , wherein the fluid comprises less than 500 ppm by weight of aromatics, preferably less than 100 ppm by weight of aromatics.

13. Use according to any one of claims 1 to 12, wherein the fluid has an aniline point ranging from 50 to 100°C, preferably from 60 to 90°C.

14. Use according to any one of claims 1 to 13, wherein the fluid used in the invention has an initial boiling point and a final boiling point in the range from 150°C to 340°C, a boiling range from 5 to 70°C, and comprises: - from 20 to 40%wt of isoparaffins, from 5 to 20%wt of n-paraffines, from 30 to 60%wt of naphthenes, less than 100 ppm of aromatics, based on the total weight of the fluid, wherein the flash point of the fluid ranges from 60 to 120°C.

15. Use according to any one of claims 1 to 14, wherein the fluid comprises less than 10%wt of mononaphthenes, from 5 to 40%wt of di-naphthenes, less than 10%wt of tri-naphthenes and from 5 to 55%wt of iso-naphthenes, based on the total weight of the fluid.

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