Flame-resistant and cooling composition

Abstract

The present invention relates to the use of a composition comprising: - at least one hydrocarbon fluid having an initial boiling point of at least 30 °C or at least one base oil, - perfluorooctyl bromide for cooling within a mobile or stationary system and / or for preventing or delaying the propagation of thermal runaway within a mobile or stationary system.

Description

[0001] Description

[0002] Title: Non-flammable and cooling composition.

[0003] Technical field

[0004] The present invention relates to the field of cooling and non-flammable compositions for static or mobile applications, in particular for electric or hybrid vehicles, in particular for cooling batteries and power electronics but also for delaying and / or preventing the spread of fire.

[0005] State of the art

[0006] The evolution of international standards for reducing CO2 emissions, but also for reducing energy consumption, is pushing car manufacturers to offer alternative solutions to combustion engines.

[0007] One solution identified by car manufacturers is to replace combustion engines with electric motors. Research into reducing CO2 emissions has therefore led to the development of electric vehicles by several car companies.

[0008] For the purposes of the present invention, the term "electric vehicle" means a vehicle comprising an electric motor as the sole means of propulsion, unlike a hybrid vehicle which comprises a combustion engine and an electric motor as combined means of propulsion.

[0009] For the purposes of the present invention, the term "propulsion system" means a system comprising the mechanical parts necessary for the propulsion of an electric vehicle. The propulsion system thus more particularly encompasses an electric motor comprising the rotor-stator assembly, power electronics (dedicated to speed regulation), a transmission (also called a reducer) and a battery.

[0010] Generally speaking, it is necessary to implement, in electric or hybrid vehicles, compositions to meet the lubrication and / or cooling constraint of the various parts of the propulsion system mentioned above. Depending on the systems, a single composition may play the role of lubrication and cooling while, in other systems, there may be both a lubricating composition dedicated to this action with respect to the elements of the propulsion system, as has just been described, and a different cooling composition, in particular for the batteries and the power electronics.

[0011] This second alternative is used in particular when hydrocarbon fluids having a boiling point greater than or equal to 30°C, and in particular between 30°C and 350°C, in particular between 30°C and 250°C, are used for cooling batteries and power electronics as will be detailed below. Such hydrocarbon fluids do not have lubricating properties.

[0012] Lubricating compositions, also known as "lubricants", are commonly used in propulsion systems, such as electric motors, primarily to reduce frictional forces between the various moving metal parts in the motors. They are also effective in preventing premature wear and even damage to these parts, particularly their surfaces.

[0013] To achieve this, a lubricating composition is typically composed of one or more base oils, to which are generally associated several additives dedicated to boosting the lubricating performance of the base oils, such as for example friction modifier additives. On the other hand, electric propulsion systems generate heat during their operation via the electric motor, power electronics and batteries. Since the amount of heat generated is greater than the amount of heat normally dissipated to the environment, it is necessary to ensure cooling of the motor, power electronics and batteries. Generally, cooling is carried out on several parts of the propulsion system generating heat and / or the parts of said system sensitive to heat, in order to avoid reaching dangerous temperatures, and in particular the power electronics and batteries.

[0014] Traditionally, electric motors are cooled with air or water, possibly combined with glycol. These cooling methods are not optimal, or even insufficient, with the new developments in the propulsion system of electric and hybrid vehicles. Flame retardants are also known that can be used in fluids, including oily ones, particularly for industrial applications, such as cleaning.

[0015] However, some virtually non-flammable oils are generally composed of heavy halogens such as polychlorotrifluoroethylenes (PCTFE). Furthermore, some perfluorinated organic fluids of the ether or ketone type are also known as coolants for the propulsion system of electric vehicles.

[0016] Despite the cooling systems implemented in the field of lubrication of the propulsion systems of electric or hybrid vehicles, the risk of the battery overheating at the cell level cannot be completely ruled out, which can lead to an explosion and an overall fire of the battery, known as the "runaway effect".

[0017] It is therefore an object of the present invention to provide a composition which is both cooling and non-flammable for cooling and fireproofing mobile or stationary systems.

[0018] Summary of the invention

[0019] More specifically, the present invention relates to the use of a composition comprising:

[0020] - at least one hydrocarbon fluid having an initial boiling point of at least 30°C or at least one base oil,

[0021] - perfluorooctyl bromide, for cooling within a mobile or stationary system and / or to prevent or delay the propagation of thermal runaway within a mobile or stationary system.

[0022] According to one embodiment, the composition comprises:

[0023] - from 15 to 99% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0024] - from 1 to 85% by weight of perfluorooctyl bromide, relative to the total weight of the composition. According to one embodiment, the composition further comprises at least one flame retardant corresponding to formula (I):

[0025] RF-L-RH (I) in which:

[0026] RF is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

[0027] RH is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, and

[0028] L is a linker chosen from the following groups: -CH2-, -CH=CH-, -O-, -S- or -PO4-,

[0029] RF and / or RH may also comprise at least one element chosen from elements of the halogen class such as preferably fluorine, bromine and / or chlorine.

[0030] According to one embodiment, the composition comprises:

[0031] - from 15 to 94% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0032] - from 1 to 75% by weight of perfluorooctyl bromide,

[0033] - from 5 to 35% by weight of flame retardant(s) corresponding to formula (I), relative to the total weight of the composition.

[0034] According to one embodiment, the composition is in direct contact with at least one organ of the mobile or stationary system.

[0035] According to one embodiment, the composition is used as a battery cooling composition, as a data center cooling composition, as a hydraulic fluid, as a cooling fluid for a 5G type antenna, as a heat transfer fluid in a heating system, as a heat transfer fluid for charging stations, including for electric vehicles, as a heat transfer fluid for energy storage systems, or as a heat transfer fluid for photovoltaic panels, as a working fluid for a heat pump.

[0036] According to one embodiment, the mobile system is a propulsion system of an electric or hybrid vehicle, preferably a battery and / or the power electronics of an electric or hybrid vehicle. According to one embodiment, the stationary system is chosen from data centers, heating systems, heat pumps, 5G type relay antennas, hydraulic systems, charging stations, including for electric vehicles, energy storage systems, or photovoltaic panels.

[0037] The invention also relates to a composition comprising, relative to the total weight of the composition:

[0038] - from 15 to 94% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0039] - from 1 to 75% by weight of perfluorooctyl bromide,

[0040] - from 5 to 35% by weight of flame retardant(s) corresponding to formula (I):

[0041] RF-L-RH (I) in which:

[0042] RF is a hydrocarbon group,

[0043] RH is a hydrocarbon group, and

[0044] L is a linker chosen from the following groups: -CH2-, -CH=CH-, -O-, -S- or -PO4-,

[0045] RF and / or RH which may also comprise an element chosen from elements of the halogen class, composition in which the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 1.

[0046] According to one embodiment of the composition according to the invention, the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 0.75, preferably less than 0.5.

[0047] The composition defined in the invention has joint cooling and fire retardant properties.

[0048] The composition defined in the invention furthermore has properties of resistance to ignition, also called non-flammability, which is useful for batteries. The present invention more particularly proposes the use of the composition defined in the present invention to satisfy at least cooling, but also to delay and / or prevent the spread of fire within the elements of the propulsion system on the one hand, as well as on the other hand to ensure the safety of batteries, in particular Lithium-ion (Li-ion) or Nickel-Cadmium (Ni-Cd) batteries, by conferring a property of resistance to ignition.

[0049] The composition defined within the scope of the present invention further exhibits improved stability. It is typically in the form of a nano-emulsion, which is more thermodynamically stable than a conventional emulsion.

[0050] In the rest of the text, the expressions "between ... and . . .", "ranging from . . . to ..." and "varying from ... to ..." are equivalent and are intended to mean that the limits are included, unless otherwise stated.

[0051] Unless otherwise indicated, quantities in a product are expressed by weight, relative to the total weight of the product.

[0052] Detailed description

[0053] The present invention relates to the use of a composition comprising:

[0054] - at least one base oil or at least one hydrocarbon fluid having an initial boiling point of at least 30°C,

[0055] - perfluorooctyl bromide, for cooling within a mobile or stationary system and / or to prevent or delay the propagation of thermal runaway within a mobile or stationary system.

[0056] Hydrocarbon fluid

[0057] For the purposes of the present invention, the term "hydrocarbon fluid" means any fluid comprising linear, saturated or unsaturated hydrocarbon molecules, which may also comprise aromatic or cyclic groups, or heteroatoms. In the context of the present invention, "paraffins" designate hydrocarbons with straight or linear chains (also called "normal paraffins") and branched chains (also called "isoparaffins").

[0058] As heteroatoms, in the context of the present invention, mention may in particular be made of nitrogen and oxygen.

[0059] The hydrocarbon fluid used in the invention has an initial boiling point of at least 30°C, preferably at least 50°C.

[0060] In addition to conventional “liquid” fluids, “gas” type fluids can be used in the composition according to the invention which can then be used as a working fluid in heat pump type systems.

[0061] According to a particular embodiment of the invention, the hydrocarbon fluid has a boiling point of between 50°C and 350°C, in particular between 60°C and 300°C, and even more particularly between 80°C and 250°C.

[0062] Preferably, the hydrocarbon fluid used in the invention has a carbon content of biological origin greater than or equal to 90% by weight, relative to the total weight of the hydrocarbon fluid.

[0063] According to a particular embodiment of the invention, the hydrocarbon fluid comprises alkanes, or linear molecules of saturated hydrocarbons with a non-cyclic chain, in particular comprising between 12 and 30 carbon atoms, in a content of between 80 and 100% by weight, relative to the total weight of the hydrocarbon fluid, or even between 90 and 100% by weight, and for example between 95 and 100% by weight.

[0064] According to a particular embodiment of the invention, the hydrocarbon fluid used in the invention comprises more than 50% by weight of isoparaffins, preferably more than 75% by weight of isoparaffins. Preferably, the components of the hydrocarbon fluid are chosen from isoparaffins comprising from 10 to 30 carbon atoms, preferably from 11 to 24 carbon atoms, and more preferably from 12 to 18 carbon atoms.

[0065] A cooling composition according to the invention advantageously comprises a weight content of isohexadecane of less than or equal to 50%. According to a particular embodiment of the invention, the hydrocarbon fluid comprises from 85 to 100% by weight of isoparaffins, and a content of normal paraffins ranging from 0 to 15% by weight.

[0066] The hydrocarbon fluid advantageously comprises a normal paraffin content of less than or equal to 10% by weight, preferably less than or equal to 5% and even more preferably less than or equal to 2% by weight, relative to the total weight of the hydrocarbon fluid.

[0067] The isoparaffins are advantageously non-cyclic isoparaffins. Preferably, the hydrocarbon fluid has a mass ratio of isoparaffins to normal paraffins of at least 12:1, preferably at least 15:1 and more preferably at least 20:1. According to an even more particular embodiment, the hydrocarbon fluid does not comprise normal paraffins.

[0068] According to one embodiment, the hydrocarbon fluid preferably comprises a weight content of isoparaffins ranging from 90 to 100% and a content of normal paraffins ranging from 0 to 10%, preferably from 95 to 100% of isoparaffins chosen from alkanes comprising from 12 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, more preferably from 12 to 22 carbon atoms.

[0069] According to a particular embodiment, the hydrocarbon fluid in accordance with the invention comprises a majority, i.e. more than 90% by weight, of molecules having from 12 to 18 carbon atoms, such as isoparaffins.

[0070] According to another embodiment, the hydrocarbon fluid in accordance with the invention comprises from 60 to 95% by weight, preferably from 80 to 98% by weight, of isoparaffins chosen from the group consisting of C15 isoparaffins, C16 isoparaffins, C17 isoparaffins, C18 isoparaffins and mixtures of two or more of them.

[0071] According to one embodiment, the hydrocarbon fluid comprises:

[0072] - isoparaffins having 15 carbon atoms and isoparaffins having 16 carbon atoms in a total amount ranging from 80 to 98% by weight, relative to the total weight of the hydrocarbon fluid, or - isoparaffins having 16 carbon atoms, isoparaffins having 17 carbon atoms and isoparaffins having 18 carbon atoms in a total amount ranging from 80 to 98% by weight, relative to the total weight of the hydrocarbon fluid, or

[0073] - isoparaffins having 17 carbon atoms and isoparaffins having 18 carbon atoms in a total quantity ranging from 80 to 98% by weight, relative to the total weight of the hydrocarbon fluid.

[0074] According to a preferred embodiment of the invention, the hydrocarbon fluid comprises isoparaffins having 17 carbon atoms and isoparaffins having 18 carbon atoms in a total amount ranging from 80 to 98% by weight, relative to the total weight of the hydrocarbon fluid.

[0075] Examples of preferred hydrocarbon fluids according to the invention are those comprising:

[0076] - from 30 to 70% by weight of C15 isoparaffins and from 30 to 70% by weight of C16 isoparaffins, preferably from 40 to 60% by weight of C15 isoparaffins and from 35 to 55% by weight of C16 isoparaffins, relative to the total weight of the hydrocarbon fluid,

[0077] - from 5 to 25% of C15 isoparaffins, from 30 to 70% of C16 isoparaffins and from 10 to 40% of C17 isoparaffins, preferably from 8 to 15% of C15 isoparaffins, from 40 to 60% of C16 isoparaffins and from 15 to 25% of C17 isoparaffins, relative to the total weight of the hydrocarbon fluid,

[0078] - from 5 to 30% of C17 isoparaffins and from 70 to 95% of C18 isoparaffins, preferably from 10 to 25% of C17 isoparaffins and from 70 to 90% of C18 isoparaffins, relative to the total weight of the hydrocarbon fluid.

[0079] The hydrocarbon fluid preferably comprises a content by weight of naphthenic compounds less than or equal to 3%, preferably less than or equal to 1%, more preferably less than or equal to 0.5% and even more preferably less than or equal to 500 ppm, or even 100 ppm or 50 ppm.

[0080] According to another preferred embodiment, the hydrocarbon fluid comprises a weight content of isoparaffins ranging from 90 to 100%, a weight content of normal paraffins ranging from 0 to 10% and a weight content of naphthenic compounds less than or equal to 1%. Preferably, the hydrocarbon fluid comprises a weight content ranging from 95 to 100% of isoparaffins, from 0 to 5% of normal paraffins and a weight content of naphthenic compounds less than or equal to 0.5%. More preferably, it comprises a weight content ranging from 98% to 100% of isoparaffins, from 0 to 2% of normal paraffins and a weight content of naphthenic compounds less than or equal to 100 ppm.

[0081] The hydrocarbon fluid is advantageously free of aromatic compounds. For example, this means a content by weight of aromatic compounds less than or equal to 500 ppm, preferably less than or equal to 300 ppm, preferably less than or equal to 100 ppm, more preferably less than or equal to 50 ppm and advantageously less than or equal to 20 ppm measured for example by UV spectrometry.

[0082] The weight content of isoparaffins, normal paraffins, naphthenic compounds and / or aromatics in the hydrocarbon fluid can be determined according to methods well known to those skilled in the art. Mention may be made, by way of non-limiting example, of a method using gas chromatography.

[0083] According to another preferred embodiment, the hydrocarbon fluid comprises a weight content of isoparaffins ranging from 90 to 100%, a weight content of normal paraffins ranging from 0 to 10%, a weight content of naphthenic compounds less than or equal to 1% and a weight content of aromatic compounds less than or equal to 500 ppm. Preferably, the hydrocarbon fluid comprises a weight content ranging from 95 to 100% of isoparaffins, from 0 to 5% of normal paraffins, a weight content of naphthenic compounds less than or equal to 0.5% and a weight content of aromatic compounds less than or equal to 300 ppm, preferably less than 100 ppm, preferably less than 50 ppm and advantageously less than 20 ppm. Preferably also the hydrocarbon fluid comprises a weight content ranging from 95 to 100% of isoparaffins, from 0 to 5% of normal paraffins and a weight content of aromatic compounds less than or equal to 100 ppm.More preferably, it comprises a weight content ranging from 98% to 100% of isoparaffins, from 0 to 2% of normal paraffins, a weight content of naphthenic compounds less than or equal to 100 ppm and a weight content of aromatic compounds less than or equal to 100 ppm.

[0084] The hydrocarbon fluid also preferably has an extremely low weight content of sulfur compounds, typically less than or equal to 5 ppm, preferably less than or equal to 3 ppm and more preferably less than or equal to 0.5 ppm at a level too low to be detected using conventional low-sulfur analyzers.

[0085] The hydrocarbon fluid also preferably has a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C and more preferably greater than or equal to 140°C according to standard EN ISO 2719. A high flash point, typically greater than 110°C, makes it possible, among other things, to overcome safety problems during storage and transport by avoiding excessive flammability of the hydrocarbon fluid.

[0086] The hydrocarbon fluid also preferably has a vapor pressure at 20°C less than or equal to 0.01 kPa.

[0087] According to one embodiment, the hydrocarbon fluid also preferably has a flash point greater than or equal to 110°C according to standard EN ISO 2719 and a vapor pressure at 20°C less than or equal to 0.01kPa. Preferably, the hydrocarbon fluid has a flash point greater than or equal to 120°C and a vapor pressure at 20°C less than or equal to 0.01kPa. And more preferably, it has a flash point greater than or equal to 140°C and a vapor pressure at 20°C less than or equal to 0.01kPa.

[0088] The hydrocarbon fluid also preferably has a kinematic viscosity at 40°C less than or equal to 5 cSt, preferably less than or equal to 4 cSt and more preferably less than or equal to 3.5 cSt according to standard EN ISO 3104.

[0089] The hydrocarbon fluid used in the invention has a carbon content of biological origin greater than or equal to 90% by weight, relative to the total weight of the hydrocarbon oil which ideally comes from the processing of raw materials of biological origin. The carbon of a biomaterial comes from the photosynthesis of plants and therefore from atmospheric CO2. The degradation (by degradation, we also understand combustion / incineration at the end of life) of these CO2 materials therefore does not contribute to global warming because there is no increase in the carbon emitted into the atmosphere. The CO2 assessment of biomaterials is therefore significantly better and contributes to reducing the carbon footprint of the products obtained (only the energy for manufacturing must be taken into account). On the contrary, a fossil material of origin also degraded into CO2 will contribute to the increase in the CO2 level and therefore to global warming.The hydrocarbon fluid used according to the invention will therefore have a carbon footprint which will be better than that of the compounds obtained from a fossil source.

[0090] The term "bio-carbon" indicates that the carbon is of natural origin and comes from a biomaterial, as shown below. Bio-carbon content and biomaterial content are expressions indicating the same value. A renewable material or biomaterial is an organic material in which the carbon comes from CO2 recently fixed (on a human scale) by photosynthesis from the atmosphere. A biomaterial (100% Naturally Occurring Carbon) has an isotopic ratio 14 C / 12 C greater than 10' 12 , typically about 1.2 x 10 12 , while a fossil material has a zero ratio. Indeed, the 14C isotope is formed in the atmosphere and is then integrated by photosynthesis, on a time scale of a few decades at most. The half-life of 14 It is 5730 years. Thus, the materials resulting from photosynthesis, namely plants in general, necessarily have a maximum isotope content 14 C.

[0091] The determination of biomaterial or bio-carbon content is given in accordance with ASTM D 6866-12, Method B (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04). ASTM D 6866 concerns the "Determination of Bio-Based Content of Natural Range Materials Using Radiocarbon-Isotope Ratio Mass Spectrometry Analysis", while ASTM D 7026 concerns "Sampling and Reporting of Results for Determination of Bio-Based Content by Carbon Isotope Analysis". The second standard mentions the former in its first paragraph.

[0092] The first standard describes a test for measuring the ratio 14 C / 12 C of a sample and compare it with the ratio 14 C / 12C of a reference sample of 100% renewable origin, to give a relative percentage of C of renewable origin in the sample. The standard is based on the same concepts as dating with 14C, but without applying the dating equations. The ratio thus calculated is indicated as "pMC" (percentage Modern Carbon). If the material to be analyzed is a mixture of biomaterials and fossil materials (without radioactive isotopes), the pMC value obtained is directly correlated to the amount of biomaterial present in the sample. The reference value used for dating 14C is a value dating from the 1950s. This year was selected due to the existence of atmospheric nuclear tests that introduced large quantities of isotopes into the atmosphere after this date. The 1950 reference corresponds to a pMC value of 100. Taking into account thermonuclear tests, the current value to be retained is approximately 107.5 (which corresponds to a correction factor of 0.93). The radioactive carbon signature of a current plant is therefore 107.5. A signature of 54 pMC and 99 pMC therefore corresponds to an amount of biomaterial in the sample of 50% and 93% respectively.

[0093] The hydrocarbon fluid in accordance with the invention has a biomaterial content of at least 90%. This content is advantageously higher, in particular greater than or equal to 95%, preferably greater than or equal to 98% and advantageously equal to 100%.

[0094] According to one embodiment, the isotopic ratio 14 C / 12 C of the hydrocarbon fluid used in the invention is between 1.15 and 1.2 x 10 12 .

[0095] In addition to a particularly high biomaterial content, the hydrocarbon fluid used in the invention can exhibit particularly good biodegradability. The biodegradation of an organic chemical refers to the reduction of the complexity of chemical compounds through the metabolic activity of microorganisms. Under aerobic conditions, microorganisms convert organic substances into carbon dioxide, water and biomass. The OECD 306 method is used for the assessment of the biodegradability of individual substances in seawater. According to this method, the hydrocarbon fluid exhibits, according to one embodiment, a biodegradability at 28 days of at least 60%, preferably at least 70%, more preferably at least 75% and advantageously at least 80%.

[0096] The OECD 306 method is as follows:

[0097] The closed bottle method involves dissolving a predetermined amount of the test substance in a control medium at a concentration typically of 2-10 mg / L, with one or more concentrations optionally being used. The solution is kept in a filled closed bottle protected from light at a constant temperature in the range 15-20°C. Degradation is monitored by oxygen analysis over a period of 28 days. 24 bottles are used (8 for the test substance, 8 for the reference compound and 8 for nutrients). All analyses are performed on multiple bottles. At least 4 dissolved oxygen determinations are performed (days 0, 5, 15 and 20) using a chemical or electrochemical method.

[0098] The hydrocarbon fluid used in the invention can be obtained according to the process described in application WO2016 / 185047.

[0099] In particular, a composition used according to the invention comprises from 15% to 99% by weight, preferably from 20% to 95%, even more preferably from 25% to 90%, advantageously from 30% to 90% by weight of at least one hydrocarbon fluid having a boiling point of at least 30°C, relative to the total weight of the composition.

[0100] Base oil(s)

[0101] The composition used according to the invention may comprise one or more base oils.

[0102] These base oils can be chosen from base oils conventionally used in the field of lubricating oils, such as mineral, synthetic or natural, animal or vegetable oils or their mixtures.

[0103] It can be a mixture of several base oils, for example a mixture of two, three, or four base oils.

[0104] The base oils of the lubricating compositions considered according to the invention may in particular be oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in table 1 below or their mixtures.

[0105] [Table 1]

[0106] Mineral base oils include all types of base oils obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, de-alphatting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0107] Blends of synthetic and mineral oils, which can be bio-sourced, can also be used.

[0108] There is generally no limitation on the use of different base oils to produce the compositions used according to the invention, except that they must have properties, in particular in terms of viscosity, viscosity index, or resistance to oxidation, suitable for use in propulsion systems of an electric or hybrid vehicle.

[0109] The base oils of the compositions used according to the invention can also be chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, polyalphaolefins (PAO), and polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides comprising from 2 to 8 carbon atoms, in particular from 2 to 4 carbon atoms.

[0110] PAOs used as base oils are, for example, obtained from monomers comprising 4 to 32 carbon atoms, for example from octene or decene. The weight-average molecular mass of the PAO can vary quite widely. Preferably, the weight-average molecular mass of the PAO is less than 600 Da. The weight-average molecular mass of the PAO can also range from 100 to 600 Da, from 150 to 600 Da, or from 200 to 600 Da.

[0111] Advantageously, the base oil or oils of the lubricating composition according to the invention may be chosen from group II or III base oils. According to an alternative embodiment, the base oil or oils of the composition used according to the invention are chosen from polyalphaolefins (PAO), polyalkylene glycol (PAG) and esters of carboxylic acids and alcohols.

[0112] In particular, a composition used according to the invention comprises from 15% to 99% by weight, preferably from 20% to 95%, even more preferably from 25% to 90%, advantageously from 30% to 90% by weight of base oil(s), relative to the total weight of the composition.

[0113] The composition used according to the invention comprises perfluorooctyl bromide (PFOB).

[0114] In particular, a composition used according to the invention comprises from 1% to 85% by weight, preferably from 5% to 80%, even more preferably from 10% to 75%, advantageously from 10% to 70% by weight of PFOB, relative to the total weight of the composition.

[0115] According to one embodiment, the composition used according to the invention has a mass ratio [PFOB] to [hydrocarbon fluid(s) and / or base oil(s)] of less than 1, preferably less than or equal to 0.75, more preferably less than or equal to 0.50.

[0116] According to one embodiment, the composition used according to the invention comprises, relative to the total weight of the composition:

[0117] - from 15 to 99% by weight, preferably from 20 to 95% by weight, more preferably from 25 to 90% by weight, of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0118] - from 1 to 85% by weight, preferably from 5 to 80% by weight, more preferably from 10 to 75% by weight, of perfluorooctyl bromide.

[0119] According to one embodiment, the composition used according to the invention further comprises at least one flame retardant corresponding to the formula (I): RF-L-RH (I) in which: RF is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

[0120] RH is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, and

[0121] L is a linker chosen from the following groups: -CH2, -CH=CH-, -O-, -S- or -PO4-, RF and / or RH may also comprise at least one element chosen from elements of the halogen class such as preferably fluorine, bromine and / or chlorine, said flame retardant being distinct from perfluorooctyl bromide.

[0122] This flame retardant of formula (I) improves the stability of the composition, in particular through the formation of a stable nano-emulsion.

[0123] According to one embodiment, the RF group is perfluorinated or partially fluorinated. In the context of the present invention, the term "partially fluorinated group" means that at least 60% of the hydrogen atoms in the group concerned have been replaced by fluorine atoms, for example between 60 and 80%.

[0124] According to a particular embodiment, the RF group comprises between 1 and 22, preferably between 1 and 20, more particularly between 1 and 16 carbon atoms. Said group may optionally be interrupted by 1 to 4 heteroatoms chosen from a nitrogen atom and an oxygen atom. This group may also be linear or branched.

[0125] Advantageously, it is a perfluorinated or partially fluorinated (Ci-Ci6)alkyl group optionally interrupted by one or two heteroatoms chosen from a nitrogen atom and an oxygen atom.

[0126] Such an RF group can for example be chosen from the following groups:

[0127] • CF3(CF2)m-,

[0128] • C(CF3)3(CF2) m -,

[0129] • (CF3)2CF(CF2) m -,

[0130] • (CF3)2CF-, and

[0131] • (CF3)CF2-,

[0132] • (CF3)(CF2)3-, with m being an integer that can be between 1 and 15.

[0133] These examples are not limiting. According to a particular embodiment, the RH group comprises between 1 and 22 carbon atoms, preferably between 1 and 20, even more preferably between 1 and 16 carbon atoms. According to a particular embodiment, this RH group may comprise between 1 and 4 heteroatoms chosen from a nitrogen atom and an oxygen atom. This group may also be linear or branched. It may also be saturated or comprise from 1 to 4 unsaturations.

[0134] Advantageously, it is a (Ci-Ci5)alkyl or (C2-Ci5)alkenyl group, said group being optionally substituted by a hydrocarbon ring such as the (C3-C6)cycloalkyl, phenyl or benzyl group.

[0135] Such an HR group may in particular be chosen from the following groups, without however being limited to:

[0136] • -(CH2) n CH3,

[0137] • -(CH2)pC6H4,

[0138] • -(CH2) q O(CH2) r CH3, and

[0139] • -(CH2) s C=C(CH2)tCH3with n being an integer which may be between 1 and 21, in particular between 7 and 21, p being between 1 and 16, in particular between 2 and 10, q and r being independently between 1 and 16, with q+r being less than or equal to 21 and advantageously greater than 7, s and t being independently between 1 and 16, with s+t being less than or equal to 19 and advantageously greater than 5.

[0140] According to a particular embodiment, the flame retardant may be chosen from the compounds of formula (I) in which RF is a perfluorinated or partially fluorinated (C2-Ci2)alkyl group, RH is a (Ci-Ci2)alkyl group, in particular (C6-Ci2)alkyl or (C2-Ci2)alkenyl group, in particular (C6-Ci2)alkenyl, said group being optionally substituted by a hydrocarbon ring such as the (C3-C6)cycloalkyl, phenyl or benzyl group, and said group being able to be interrupted by 1 or 2 heteroatoms chosen from nitrogen or oxygen, and L is a linker chosen from -CH2-, -CH=CH- and -O-. It is understood in the context of the present invention that the flame retardant of formula (I) as defined above may be in the form of a mixture of flame retardants of formula (I) as defined above.

[0141] For the purposes of the present invention, the following terms are defined as follows:

[0142] - "(Ci-Cj) alkyl" refers to a saturated hydrocarbon chain comprising from i to j carbon atoms, linear or branched, for example a (Ci-Ci2)alkyl group. Non-limiting examples include the following groups: methyl, ethyl, 1-propyl, 2-propyl, butyl, pentyl, hexyl, heptyl, and decyl,

[0143] - "(C2-C x ) alkenyl", refers to a hydrocarbon chain having unsaturations and comprising from 2 to x carbon atoms, linear or branched, for example a (C2-C12)alkyl group. Non-limiting examples include the following groups: ethylene, propylene, butylene, pentylene, hexylene and decylene

[0144] - "(C3-C6)cycloalkyl", with a saturated and cyclic hydrocarbon chain. Non-limiting examples include the following groups: cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0145] According to the present invention, the flame retardant(s) of formula (I) may be present in a content of between 5 and 35% by weight, relative to the total weight of the composition used according to the present invention, in particular in a content of between 7% and 30% by weight, even more particularly in a content of between 10% and 20% by weight.

[0146] Thus, according to one embodiment, the composition used according to the invention comprises:

[0147] - from 15 to 90% by weight, preferably from 40 to 90% by weight, of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0148] - from 5 to 75% by weight, preferably from 7 to 50% by weight, of perfluorooctyl bromide,

[0149] - from 5 to 35% by weight, preferably from 7 to 50% by weight, of flame retardant(s) corresponding to formula (I), relative to the total weight of the composition. Additional additives

[0150] Additional additives may be implemented in the cooling composition of the invention. Among these additives, mention may be made of antioxidants, anti-corrosion additives, anti-foam additives and pour point depressants.

[0151] According to a particularly preferred embodiment, the cooling composition according to the invention comprises at least one antioxidant additive.

[0152] The antioxidant additive generally helps to delay the degradation of the composition in service. This degradation can notably result in the formation of deposits, the presence of sludge or an increase in the viscosity of the composition.

[0153] Antioxidant additives act in particular as radical inhibitors or hydroperoxide destroyers. Among the commonly used antioxidant additives, mention may be made of phenolic antioxidant additives, amine antioxidant additives, and phosphosulfur antioxidant additives. Some of these antioxidant additives, for example phosphosulfur antioxidant additives, may be ash-generating. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. The antioxidant additives may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C1-C12 alkyl group, N,N'-dialkylaryldiamines and mixtures thereof.

[0154] Preferably according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group of which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C1-C10 alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably by the tert-butyl group.

[0155] Amino compounds are another class of antioxidant additives that can be used, possibly in combination with phenolic antioxidant additives. Examples of amino compounds are aromatic amines, for example aromatic amines of the formula NR 4 R 5 R 6 in which R 4 represents an aliphatic group or an aromatic group, optionally substituted, R 5 represents an aromatic group, optionally substituted, R 6represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R 7 S(O) Z R 8 in which R 7 represents an alkylene group or an alkenylene group, R 8 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

[0156] Sulfurized alkyl phenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

[0157] Another class of antioxidant additives is copper compounds, e.g. copper thio- or dithio-phosphates, copper salts of carboxylic acids, dithiocarbamates, sulphonates, phenates, copper acetylacetonates. Copper I and II salts, succinic acid or anhydride salts can also be used.

[0158] The cooling composition according to the invention or used according to the invention may contain all types of antioxidant additives known to those skilled in the art.

[0159] The cooling composition according to the invention or used according to the invention may comprise from 0.1 to 2% by weight of at least one antioxidant additive, relative to the total weight of the composition.

[0160] According to a particular embodiment, the cooling composition according to the invention or used according to the invention is free of antioxidant additive of aromatic amine type or sterically hindered phenol type.

[0161] The cooling composition according to the invention or used according to the invention may comprise at least one anti-corrosion additive.

[0162] The anti-corrosion additive advantageously helps to delay or prevent corrosion of the metal parts of the battery.

[0163] A cooling composition according to the invention or used according to the invention may comprise from 0.01 to 2% by mass or from 0.01 to 5% by mass, preferably from 0.1 to 1.5% by mass or from 0.1 to 2% by mass of anti-corrosion agent, relative to the total weight of the composition.

[0164] The cooling composition according to the invention or used according to the invention may further comprise at least one antifoaming agent.

[0165] The antifoaming agent may be chosen from polyacrylates or waxes. The cooling composition according to the invention may comprise from 0.01 to 2% by mass or from 0.01 to 5% by mass, preferably from 0.1 to 1.5% by mass or from 0.1 to 2% by mass of antifoaming agent, relative to the total weight of the composition.

[0166] The cooling composition according to the invention or used according to the invention may also comprise at least one pour point lowering additive (also called “PPD” agents for “Pour Point Depressant” in English).

[0167] By slowing the formation of paraffin crystals, pour point depressants generally improve the cold behavior of the composition. Examples of pour point depressants include polyalkyl methacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, and alkylated polystyrenes.

[0168] The cooling composition according to the invention or used according to the invention may further comprise at least one radical inhibitor.

[0169] Such radical inhibitors are per se known to those skilled in the art and may have different chemical natures and in particular belong to different chemical families.

[0170] In terms of formulation of the composition according to the present invention or used according to the invention, all methods known to those skilled in the art can be used for this additivation of the fluid or oil.

[0171] Among the radical inhibitors, we can notably cite phosphorus radical inhibitors.

[0172] Among the phosphorus radical inhibitors, a distinction is made between compounds for which the phosphorus is a P(V) or pentavalent phosphorus and compounds for which the phosphorus is a P(III) or trivalent phosphorus.

[0173] Among these compounds in the form of pentavalent phosphorus, P(V), we can notably cite the phosphate family and in particular, triethylphosphate, trimethylphosphate, possibly fluorinated alkylphosphates or even arylphosphates.

[0174] As fluorinated alkylphosphate, we can notably cite tris (2,2,2-trifluoroethyl)phosphate. As arylphosphates, we can notably cite triphenylphosphate, tricresylphosphate or trixylenylphosphate.

[0175] Still among these compounds in the P(V) form, we can notably cite the phosphazene family. In this family, which is characterized by the fact that its representatives have at least one double bond between a pentavalent phosphorus atom and a nitrogen atom, cyclic compounds are favored. We can notably cite hexamethoxycyclotriphosphazene.

[0176] Among these compounds in the form of trivalent phosphorus, P(III), we can notably cite the phosphite family. In this family, we can notably cite tris(2,2,2-trifluoroethyl)phosphite.

[0177] When the cooling composition is implemented in a lubrication system, the cooling composition according to the invention or used according to the invention may also further comprise all types of additives suitable for use in a lubricant for the propulsion system of an electric or hybrid vehicle and may be called a lubricating composition.

[0178] Such additives, known to those skilled in the art in the field of lubrication of propulsion systems of electric or hybrid vehicles, may be chosen from friction modifiers, detergents, anti-wear additives, extreme pressure additives, dispersants, and mixtures thereof.

[0179] The composition used according to the invention or used according to the invention can be prepared by simply mixing the ingredients.

[0180] The composition defined in the invention is used for cooling within a mobile or stationary system and / or for preventing or delaying the propagation of thermal runaway within a mobile or stationary system.

[0181] Preferably, the composition is in direct contact with at least one organ of the mobile or stationary system.

[0182] Preferably, the composition is used as a battery cooling composition (for mobile or stationary applications), as a data center cooling composition, as a hydraulic fluid, as a cooling fluid for a 5G type antenna, as a heat transfer fluid in a heating system, for charging stations, including for electric vehicles, for energy storage systems, or for photovoltaic panels, as a working fluid for a heat pump.

[0183] According to one embodiment, the mobile system is a propulsion system of an electric or hybrid vehicle, preferably a battery and / or the power electronics of an electric or hybrid vehicle. The composition defined in the present invention can be placed in direct contact with the propulsion system and cool the engine, the power electronics and the battery by means of this direct contact of said composition on these components, while ensuring increased safety in the event of racing of said battery. The composition thus in direct contact with these components provides better cooling than conventional cooling by air and indirect contact by water. This direct contact allows better heat dissipation.

[0184] Indeed, state-of-the-art air cooling allows direct cooling, but air is a very poor fluid for dissipating heat. Conversely, water is an efficient fluid for cooling, but is not compatible with direct contact with the motor, power electronics, and battery.

[0185] Advantageously, the composition used according to the invention is brought into contact with the battery, by immersion or semi-immersion to play its dual role with respect to the batteries: cooling and fire protection.

[0186] By "immersion" is meant that the entire battery is surrounded by the cooling composition according to the present invention. By "semi-immersion" is meant that only a portion of the battery is in contact with said composition.

[0187] Alternatively, the cooling composition according to the invention is advantageously brought into direct contact with the batteries by methods described below. As batteries suitable for the propulsion systems of an electric or hybrid vehicle, mention may be made of Li-ion batteries or Nickel-Cadmium batteries. An electric motor is typically powered by an electric battery. Lithium-ion batteries are the most widespread in the field of electric vehicles. The development of increasingly powerful batteries of increasingly smaller size implies the appearance of the problem of cooling this battery. Indeed, as soon as the battery exceeds temperatures of the order of 50 to 60°C, there is a high risk of ignition, or even explosion, of the battery.There is also a need to keep the battery at a temperature above about 20 to 25°C to prevent the battery from discharging too quickly and to prolong its lifespan.

[0188] The battery may be immersed or semi-immersed, static or circulating, in the composition defined in the invention.

[0189] Examples of direct contact include cooling by injection, jet, spraying or even by forming a mist from the composition according to the invention under pressure and by gravity on the battery.

[0190] Advantageously, the composition is injected by jet under fairly high pressure into the areas to be cooled of the propulsion system. Advantageously, the shear resulting from this injection makes it possible to reduce the viscosity of the fluid at the injection zone, compared to the kinematic viscosity at rest, and thus, to further increase the cooling potential of the composition.

[0191] According to one embodiment, the composition defined in the invention is used both to cool and to prevent or delay the spread of fire at the level of the power electronics and the battery in a propulsion system of an electric or hybrid vehicle and to lubricate the transmissions in a propulsion system of an electric or hybrid vehicle.

[0192] According to one embodiment, the composition defined in the invention is used both for cooling, for preventing or delaying the spread of fire and for lubricating the engine in a propulsion system of an electric or hybrid vehicle.

[0193] According to one embodiment, the stationary system is chosen from data centers, heating systems, heat pumps, hydraulic systems, 5G type antennas, charging stations, including for electric vehicles, energy storage systems, or even photovoltaic panels.

[0194] The data economy is booming. Many aspects of our daily lives (smart devices, homes, cities, and autonomous vehicles) depend on data centers. These centers have a significant cost in terms of energy consumption. Traditionally, these data centers are cooled by air conditioning, but the invention proposes to cool these data centers using the composition of the invention, preferably by immersing the data center components in the composition defined in the invention.

[0195] The invention also relates to a method for cooling and / or fireproofing a mobile or stationary system, comprising at least one step of bringing at least one member of the mobile or stationary system into contact with the composition defined in the present invention. In particular, the method comprises at least one step of heat exchange between the composition and the member of the mobile or stationary system.

[0196] The invention also relates to a method for cooling and fireproofing a battery of a propulsion system of an electric or hybrid vehicle comprising at least one step of bringing at least one battery, in particular a Lithium-ion or Nickel-Cadmium battery, into contact with a composition as defined above. According to a particular embodiment, the contacting step consists of immersing or semi-immersing the battery in said composition or even injecting said composition onto the surface of the battery.

[0197] The invention also relates to a composition as such, comprising, relative to the total weight of the composition:

[0198] - from 15 to 90% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0199] - from 5 to 75% by weight of perfluorooctyl bromide,

[0200] - from 5 to 35% by weight of flame retardant(s) corresponding to formula (I):

[0201] RF-L-RH (I) in which:

[0202] RF is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

[0203] RH is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, and

[0204] L is a linker chosen from the following groups: -CH2, -CH=CH-, -O-, - S- or -PO4-, RF and / or RH may also comprise an element chosen from the elements of the halogen class such as preferably fluorine, bromine and / or chlorine, composition in which the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 1.

[0205] The hydrocarbon fluid(s) used in the composition according to the invention may have one or more of the characteristics defined within the framework of the use according to the invention.

[0206] The base oil(s) used in the composition according to the invention may have one or more of the characteristics defined within the framework of the use according to the invention.

[0207] The flame retardant(s) of formula (I) used in the composition according to the invention may have one or more of the characteristics defined in the context of the use according to the invention.

[0208] The composition according to the invention may further comprise one or more additives as defined in the context of the use according to the invention.

[0209] According to one embodiment of the composition according to the invention, the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 0.75, preferably less than 0.5.

[0210] According to one embodiment, the composition according to the invention comprises:

[0211] - from 15 to 90% by weight, preferably from 40 to 90% by weight, of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s),

[0212] - from 5 to 75% by weight, preferably from 7 to 50% by weight, of perfluorooctyl bromide,

[0213] - from 5 to 35% by weight, preferably from 7 to 50% by weight, of flame retardant(s) corresponding to formula (I), relative to the total weight of the composition.

[0214] The composition according to the invention can be implemented according to the use(s) and according to the method(s) defined in the invention. Examples

[0215] Example 1: Preparation of the tested compositions

[0216] F6H10 represents 1,1,1,2,2,3,3,4,4,5,5,6,6-Tridecafluorohexadecane. PAO 2 denotes a polyalphaolefin having a kinematic viscosity at 100°C of about 2.

[0217] Tested compositions are described in Tables 2 and 3, where the proportions are indicated in mass percentage in Table 2 and Table 3.

[0218] [Table 2]

[0219] [Table 3] Example 2: Measurement of interfacial tension

[0220] The interfacial tension of different compositions was measured with a TECLIS tensiometer according to the following method: Axisymmetric bubble shape analysis was applied to an ascending air bubble (2-3 pL) formed at the end of a steel capillary (tip diameter 1 mm) in the hydrocarbon, a pure F6H10 solution, a solution of F6H10 in the hydrocarbon, or in a ternary microemulsion placed in the measuring cell (10 mL). The time dependence of the surface tension during adsorption at the air / water interface was measured using a Tracker® tensiometer (Teclis Scientific, Lyon, France). The bubble volume was kept constant during the measurements, except for experiments performed in oscillating mode (AA = 15%, t = 10s).

[0221] Oscillating bubble measurements: Oscillations were produced by a position-encoded motor and transmitted by a piston coupled to the syringe carrying the capillary. The oscillatory regime was applied when the expected bubble volume was reached. The given s values ​​are average values ​​obtained by processing the data with a low-pass digital filter (3rd-order butterfly). The viscoelastic moduli were calculated as E = dg / dlnA.

[0222] The surface tension is shown in Table 4.

[0223] [Table 4]

[0224] The compositions according to the invention II and 12 have a lower surface tension than the compositions CCI, CC2, CC3 and CC4 comprising either the fluid alone or the mixture of the fluid and a flame retardant.

[0225] A low surface tension allows for a better capacity to cool and limit the spread of fire since the composition will then have the capacity to cover the surfaces of interest during a rise in temperature.

[0226] Example 3: Measurement of the viscoelastic modulus

[0227] The viscoelastic modulus of different compositions was measured according to the method described in Example 2.

[0228] The viscoelastic modulus is shown in Table 5. [Table 5]

[0229] The compositions according to the invention 13 and 14 have a viscoelastic modulus significantly lower than the compositions CCI, CC5, CC6 and CC7 comprising either the base fluid / oil alone or the mixture of the base fluid / oil and a flame retardant.

[0230] A low viscoelastic modulus allows for a better capacity to cool and limit the spread of fire since the composition will then have the capacity to cover the surfaces of interest during a rise in temperature.

Claims

Demands 1. Use of a composition comprising: - at least one hydrocarbon fluid having an initial boiling point of at least 30°C or at least one base oil, - Perfluorooctyl bromide, for cooling within a mobile or stationary system and / or to prevent or delay the propagation of thermal runaway within a mobile or stationary system.

2. Use according to claim 1, wherein the composition comprises: - 15 to 99% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s), - from 1 to 85% by weight of perfluorooctyl bromide, relative to the total weight of the composition.

3. Use according to claim 1 or 2, wherein the composition further comprises at least one flame retardant conforming to formula (I): RF-L-RH (I) wherein: RF is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, RH is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, and L is a linker chosen from the following groups: -CH2-, -CH=CH-, -O-, -S- or -PO4-, RF and / or RH which may also include at least one element chosen from the elements of the halogen class such as preferentially fluorine, bromine and / or chlorine.

4. Use according to claim 3, wherein RF is perfluorinated or partially fluorinated, preferably RF is a perfluorinated or partially fluorinated (Ci-Ci6)alkyl group optionally interrupted by one or two heteroatoms selected from a nitrogen atom and an oxygen atom.

5. Use according to claim 3 or 4, wherein the composition comprises: - 15 to 94% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s), - from 1 to 75% by weight of perfluorooctyl bromide, - 5 to 35% by weight of flame retardant(s) meeting formula (I), relative to the total weight of the composition.

6. Use according to any one of claims 1 to 5, wherein the composition is in direct contact with at least one part of the moving or stationary system.

7. Use according to any one of claims 1 to 6, wherein the composition is used as a battery cooling composition, as a data center cooling composition, as a hydraulic fluid, as a cooling fluid for a 5G antenna, as a heat transfer fluid in a heating system, as a heat transfer fluid for charging stations, including for electric vehicles, as a heat transfer fluid for energy storage systems, or as a heat transfer fluid for photovoltaic panels, as a working fluid for a heat pump.

8. Use according to any one of claims 1 to 7, wherein the mobile system is a propulsion system of an electric or hybrid vehicle, preferably a battery and / or the power electronics of an electric or hybrid vehicle.

9. Use according to any one of claims 1 to 7, wherein the stationary system is selected from data centers, heating systems, heat pumps, 5G type relay antennas, hydraulic systems, charging stations, including for electric vehicles, energy storage systems, or photovoltaic panels.

10. Composition comprising, in relation to the total weight of the composition: - 15 to 94% by weight of hydrocarbon fluid(s) having an initial boiling point of at least 30°C and / or base oil(s), - from 1 to 75% by weight of perfluorooctyl bromide, - 5 to 35% by weight of flame retardant(s) meeting the formula (I): RF-L-RH (I) in which: RF is a hydrocarbon group, RH is a hydrocarbon group, and L is a linker chosen from the following groups: -CH2-, -CH=CH-, -O-, -S- or -PO4-, RF and / or RH which may also include an element chosen from the elements of the halogen class, composition in which the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 1.

11. Composition according to claim 10, wherein the mass ratio of perfluorooctyl bromide to hydrocarbon fluid(s) and / or base oil(s) is less than 0.75, preferably less than 0.

5.

12. Composition according to claim 10 or 11, wherein RF is perfluorinated or partially fluorinated, preferably RF is a perfluorinated or partially fluorinated (Ci-Ci6)alkyl group optionally interrupted by one or two heteroatoms selected from a nitrogen atom and an oxygen atom.

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