阅读说明：本技术 用于电动或混合动力车辆的推进系统的冷却和阻燃组合物 (Cooling and flame-retardant composition for propulsion systems of electric or hybrid vehicles ) 是由 E·拉克鲁瓦 P·希纳 F·龙德莱兹 于 2019-07-10 设计创作，主要内容包括：本发明涉及包含至少一个电池的电动或混合动力车辆的推进系统的冷却组合物,该组合物包含：(i)至少一种基础油,或者至少一种沸点大于或等于50℃的烃基流体；(ii)至少一种对应于式(I)R-F-L-R-H(I)的阻燃剂,其中R-F是全氟化或部分氟化的基团,R-H是烃基基团,并且L是连接基；以及(iii)至少一种沸点为50℃-250℃的氟化化合物。本发明还涉及至少一种沸点为50℃-250℃的氟化化合物用于促进在观察到温度失控时对应于式(I)的阻燃剂与电动或混合动力车辆的推进系统的元件之间的接触的用途,所述式(I)的阻燃剂在基础油或沸点大于或等于50℃的烃基流体中配制。最后,本发明涉及电动或混合动力车辆的推进系统的至少一个电池的冷却和防火方法,该方法包括至少一个使至少一个电池与本发明的组合物接触的步骤。(The present invention relates to a cooling composition for a propulsion system of an electric or hybrid vehicle comprising at least one battery, the composition comprising: (i) at least one base oil, or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃; (ii) at least one corresponding to formula (I) R F ‑L‑R H (I) Wherein R is F Is a perfluorinated or partially fluorinated group, R H Is a hydrocarbyl group, and L is a linking group; and (iii) at least one fluorinated compound having a boiling point in the range of 50 ℃ to 250 ℃. The invention also relates to the use of at least one fluorinated compound having a boiling point of between 50 ℃ and 250 ℃ for promoting contact between a flame retardant corresponding to formula (I) formulated in a base oil or a hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃ and an element of a propulsion system of an electric or hybrid vehicle when a temperature runaway is observed. Finally, the invention relates to a method for cooling and preventing fires in at least one battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of bringing the at least one battery into contact with a composition according to the invention.)

1. A cooling composition for a propulsion system of an electric or hybrid vehicle comprising at least one battery, the composition comprising:

(i) at least one base oil, or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃;

(ii) at least one flame retardant corresponding to formula (I)

R_F-L-R_H (I)

Wherein

R_FIs a perfluorinated or partially fluorinated group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

R_His a hydrocarbyl group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16, carbon atoms, and

l is a linker; and

(iii) at least one fluorinated compound having a boiling point of 50 ℃ to 250 ℃.

2. Composition according to claim 1, characterized in that the fluorinated compound having a boiling point of between 50 and 250 ℃ is different from the flame retardant corresponding to formula (I) and in that the base oil or hydrocarbon-based fluid having a boiling point of greater than or equal to 50 ℃ is present in the composition in a content of greater than or equal to 80% by weight, preferably between 80% and 99.5% by weight, with respect to the total weight of the composition.

3. Composition according to claim 1 or 2, characterized in that the mass ratio flame retardant/fluorinated compound with a boiling point of 50-250 ℃ corresponding to formula (I) is between 0.2 and 200, preferably between 0.5 and 50.

4. Composition according to any one of the preceding claims, characterized in that it comprises micelles formed by the flame retardant corresponding to formula (I) as defined in claim 1, which contain fluorinated compounds having a boiling point of between 50 and 250 ℃.

5. Composition according to any one of the preceding claims, characterized in that L is chosen from the following divalent groups: -CH₂-, -CH ═ CH-, -O-, -S-or-PO₄-。

6. Composition according to any one of the preceding claims, characterized in that the flame retardant of formula (I) is present in a content ranging from 0.5% to 40% by weight, in particular from 2% to 30% by weight, even more particularly from 2% to 20% by weight and advantageously from 3% to 10% by weight, relative to the total weight of the composition.

7. Composition according to any one of the preceding claims, characterized in that the fluorinated compound has a boiling point of between 55 ℃ and 120 ℃.

8. Composition according to any one of the preceding claims, characterized in that the fluorinated compound is a perfluorinated compound.

9. Composition according to any one of the preceding claims, characterized in that the fluorinated compound is chosen from perfluorooctane, perfluorocyclohexane and mixtures thereof.

10. Composition according to any one of the preceding claims, characterized in that the fluorinated compound is present in the composition in a content ranging from 0.01% to 20% by weight, in particular from 0.1% to 10% by weight, even more preferably from 0.2% to 5% by weight, relative to the total weight of the composition.

11. Composition according to any one of the preceding claims, characterized in that the base oil is chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, polyalphaolefins, and polyalkylene glycols obtained by polymerization or copolymerization of alkylene oxides containing from 2 to 8 carbon atoms, in particular from 2 to 4 carbon atoms.

12. Composition according to any one of claims 1 to 10, characterized in that the hydrocarbon-based fluid has a boiling point of from 50 to 350 ℃, in particular from 60 to 250 ℃, even more particularly from 80 to 200 ℃.

13. Composition according to any one of claims 1 to 10, characterized in that the hydrocarbon-based fluid is fully saturated and preferably the components of the hydrocarbon-based fluid are chosen from isoparaffins comprising from 12 to 30 carbon atoms, preferably from 13 to 19 carbon atoms and more preferably from 14 to 18 carbon atoms.

14. Composition according to any one of claims 1 to 10, characterized in that the hydrocarbon-based fluid comprises a content of isoparaffins greater than or equal to 90% by weight, in particular greater than or equal to 95% by weight and even more advantageously greater than or equal to 98% by weight, relative to the total weight of the hydrocarbon-based fluid.

15. Composition according to any one of claims 1 to 10, characterized in that the hydrocarbon-based fluid is obtained by a catalytic hydrogenation process of deoxygenated and/or isomerized feedstock of biological origin at a temperature of between 80 ℃ and 180 ℃ and at a pressure of between 50 bar and 160 bar.

16. Composition according to any one of claims 1 to 10, characterized in that the hydrocarbon-based fluid has a weight content of isoparaffin of 98% to 100% relative to the total weight of the hydrocarbon-based fluid, and a kinematic viscosity at 40 ℃ of less than or equal to 5cSt, preferably less than or equal to 4cSt, and preferably less than or equal to 3.5 cSt.

17. The composition of claim 1, wherein the composition comprises:

(i) from 60% to 99.5% by weight, preferably from 70% to 98% by weight, even more preferably from 80% to 98% by weight and advantageously from 90% to 97% by weight, of at least one base oil or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃, relative to the total weight of the composition;

(ii) 2% to 30% by weight, preferably 2% to 20% by weight and advantageously 3% to 10% by weight of a flame retardant corresponding to formula (I), relative to the total weight of the composition; and

(iii) from 0.01% to 20% by weight, preferably from 0.1% to 10% by weight and even more particularly from 0.2% to 5% by weight, of a fluorinated compound having a boiling point of from 50 to 250 ℃, relative to the total weight of the composition.

18. Use of at least one fluorinated compound having a boiling point of between 50 ℃ and 250 ℃ for promoting the contact, when a temperature runaway is observed, in particular starting from a temperature of 50 ℃, in particular 55 ℃, between a flame retardant corresponding to formula (I) as defined in claim 1, formulated in a base oil or a hydrocarbon-based fluid having a boiling point of greater than or equal to 50 ℃, and an element of a propulsion system of an electric or hybrid vehicle, in particular a battery or power electronics and more particularly a battery.

19. Method for cooling and fire-proofing at least one battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of bringing the at least one battery, in particular a lithium-ion or nickel-cadmium battery, into contact with a composition as defined according to any one of claims 1 to 17.

20. The method according to claim 19, wherein the at least one cell is immersed or semi-immersed in the composition in a static or cyclic manner, or the composition is in direct contact with the cell by injection, spraying, by spraying, or by forming a mist from the composition under pressure and by gravity on the cell.

Technical Field

The present invention relates to the field of propulsion systems for electric or hybrid vehicles and more particularly to measures for lubricating and/or cooling thereof. The invention thus aims to propose a composition having at least the properties of cooling the power electronics and the battery, and optionally of lubricating the transmission of the propulsion system, and of combining the properties of the engine of the propulsion system of an electric or hybrid vehicle. The composition also has flame resistance properties, which show its benefits to the battery. In other words, the invention aims in particular to propose a measure for cooling the battery of an electric or hybrid vehicle via a fluid which is able to cool but also delay and/or avoid the spread of flames.

Background

For reduction of CO₂The evolution of international standards for emissions and also for reducing energy consumption has forced automobile manufacturers to propose alternative solutions for internal combustion engines.

One of the solutions identified by automotive manufacturers is to replace the internal combustion engine with an electric motor. For reduction of CO₂Emissions research has therefore led a certain number of automotive companies to develop electric vehicles.

The term "electric vehicle" in the meaning of the present invention refers to a vehicle comprising an electric motor as sole propulsion means, in contrast to a hybrid vehicle comprising an internal combustion engine and an electric motor as combined propulsion means.

The term "propulsion system" in the meaning of the present invention refers to a system comprising mechanical components necessary for propelling an electric vehicle. The propulsion system thus more specifically comprises an electric motor, comprising a rotor-stator assembly, power electronics (dedicated to speed regulation), a transmission and a battery.

In general, it is desirable to use compositions in electric or hybrid vehicles that meet the constraints of lubricating and/or cooling the components of the propulsion system described above.

Depending on the system, the same composition may act as a lubricant and coolant, while in other systems there may be a lubricating composition dedicated to the lubricating action on the elements of the propulsion system (as described above), and a different cooling composition, in particular for batteries and power electronics.

This second alternative is used in particular in the following cases: when hydrocarbon-based fluids having a boiling point greater than or equal to 50 ℃, particularly from 50 to 350 ℃, particularly from 60 to 200 ℃, even more particularly from 80 to 150 ℃ are used for cooling batteries and power electronics (as described in more detail below). Such hydrocarbon-based fluids do not have any lubricating properties.

The cooling and optionally lubricating composition according to the invention ensures the safety of the battery while cooling the battery.

According to a particular embodiment, the composition according to the invention performs a dual role of cooling and lubrication.

Still according to this embodiment, the composition acts as both a lubricant and a cooling for the motor itself. With respect to power electronics, the composition acts as a cooling. The transmission is lubricated by the composition and finally the battery is cooled by said composition.

Lubricating compositions, also known as "lubricants", are commonly used in propulsion systems, such as electric motors, for the primary purpose of reducing friction between the various metal parts moving in the engine. Furthermore, they are also effective in preventing premature wear and even damage to these components (especially to their surfaces).

To this end, lubricating compositions are typically composed of one or more base oils to which are generally combined various additives that are specific to stimulating the lubricating properties of the base oil (e.g., friction modifying additives).

On the other hand, electric propulsion systems generate heat via the electric motor, power electronics, and battery during their operation. Since the heat generated is greater than that normally dissipated to the environment, cooling of the engine, power electronics and battery must be ensured. In general, in order to avoid reaching dangerous temperatures, cooling is performed on portions of the propulsion system generating heat and/or portions of the system that are sensitive to heat, particularly on the power electronics and the battery.

Traditionally, it is known to cool the motor using air or using water, optionally in combination with glycol. With the recent development of propulsion systems for electric and hybrid vehicles, these cooling are not optimal or even insufficient.

It is also known that flame retardants can be used in fluids, including oily fluids, particularly for industrial applications.

However, some nearly nonflammable oils are typically composed of heavy halogenated compounds such as Polychlorotrifluoroethylene (PCTFE). Furthermore, certain perfluorinated organic fluids of ether or ketone type are also known to be used as cooling fluids for propulsion systems of electric vehicles.

These halogenated compounds are very expensive and their use is not preferred for regulatory and environmental reasons. Furthermore, these halogenated compounds have a high density, which increases the quality of the battery and, ultimately, reduces the endurance time of the vehicle.

Although cooling systems are known in the field of lubrication of propulsion systems of electric or hybrid vehicles, the risk of overheating in the battery unit cannot be completely eliminated, which may lead to explosions and fires of the entire battery, which is known as "runaway effect". This is particularly a concern when operating Li-ion batteries, which are specifically addressed in the context of the present invention.

Disclosure of Invention

The present invention is precisely aimed at proposing a new composition which makes it possible, at least on the one hand, to satisfy the cooling of the elements of the propulsion system described above, and on the other hand, to ensure the safety of the batteries, in particular lithium-ion (Li-ion) or nickel-cadmium (Ni-Cd) batteries, by conferring flame-resistant properties.

More precisely, the inventors have found that by using at least one flame retardant of formula (I), as defined below, in a cooling composition comprising at least one hydrocarbon-based fluid having a boiling point of at least 50 ℃, in combination with at least one fluorinated compound having a boiling point of 50-250 ℃, preferably 55-120 ℃, it is possible to ensure at least the cooling function as well as the anti-combustion function of the propulsion system for electric or hybrid vehicles.

The composition so formed may be in direct contact with the propulsion system and cool these components through such direct contact of the composition with the motor, power electronics and battery, while ensuring increased safety in the event of runaway (unbalance) of the battery.

The composition in direct contact with these components therefore provides better cooling than conventional cooling by indirect contact with air as well as with water. This direct contact may provide better heat dissipation.

In fact, cooling by air enables direct cooling, but air is a very poor heat sink fluid. In contrast, water is a high performance fluid used for cooling, but is incompatible with direct contact with the engine, power electronics, and battery.

The subject of the present invention, therefore, according to a first aspect thereof, is a cooling composition for a propulsion system of an electric or hybrid vehicle comprising at least one battery, the composition comprising:

(i) at least one base oil, or at least one hydrocarbon-based fluid (hydrocarbon) having a boiling point greater than or equal to 50 ℃;

(ii) at least one flame retardant corresponding to formula (I)

R_F-L-R_H (I)

Wherein

R_FIs a perfluorinated or partially fluorinated group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

R_His a hydrocarbyl radical, said radical containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16, carbon atoms, and

l is a linker; and

(iii) at least one fluorinated compound having a boiling point of 50 ℃ to 250 ℃.

The subject of the invention is also the use of at least one fluorinated compound having a boiling point of between 50 ℃ and 250 ℃ for promoting the contact, when a temperature runaway is observed, in particular starting from a temperature of 50 ℃, in particular 55 ℃, between a flame retardant corresponding to formula (I) formulated in a base oil or a hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃, and an element of a propulsion system of an electric or hybrid vehicle, in particular a battery or power electronics and more particularly a battery, as defined above.

The composition thus obtained advantageously comprises micelles formed by the flame retardant of formula (I) as defined above, comprising fluorinated compounds having a boiling point of between 50 and 250 ℃, preferably between 55 and 120 ℃, the purpose of said compounds being to cause the breakage of said micelles and to allow the flame retardant compound of formula (I) as defined below to fully exert its flame retardant function once the elements of the propulsion system are overheated, and more precisely when at least one battery becomes overheated.

Thus, in the case of a sharp increase in temperature, fluorinated compounds having a boiling point of from 50 to 250 ℃, preferably from 55 to 120 ℃, behave as initiators in which the micelles formed in the presence of the flame retardant of formula (I) as defined below are at least partially broken. In other words, the purpose of the fluorinated compound is to promote contact between the flame retardant of formula (I) and the battery which requires cooling (in particular rapid cooling) in the event of its runaway.

In fact, in the absence of such fluorinated compounds having a boiling point of between 50 and 250 ℃, the micelles remain in micellar form and the fluorinated component or group R of the flame retardant of formula (I) is defined as follows_FHas the disadvantage of not being fully exploited due to the lack of optimal contact between the fluorinated component and the superheating battery. In particular, the fluorinated component remains in the core of the micelle while the micelle remains intact, thereby limiting direct contact with the battery. Alternatively, the amount of said flame retardant of formula (I) as defined below has to be increased considerably, which is not desirable.

In other words, in order to prevent such a risk that micelles of the composition circulating around the various elements of the propulsion system would not function, or at least partially not function, in the event of overheating or runaway of the battery, the presence of a fluorinated compound having a boiling point of 50-250 ℃ allows the flame retardant of formula (I) defined below to enter the surface of the composition, resulting in the fluorinated component or group R of the flame retardant of formula (I)_FThe contact with the elements of the propulsion system to be protected against fire, in particular the battery, is increased.

More particularly, the lubricating composition so additivated is intended to be in direct contact with a battery of an electric vehicle, in particular a Li-ion battery or a Ni-Cd battery (which is immersed or semi-immersed in the additivated lubricating composition or the composition according to the invention, in particular in a static or cyclic manner), or directly atomized in the form of an oil spray, jet or mist.

The invention also relates to a method for cooling and preventing fires in 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 according to the invention.

Further characteristics, variants and advantages of the use of the composition according to the invention will become clearer from reading the following description and the attached drawings, given as a non-limiting illustration of the invention.

In the context of the present invention, the following terms can be used without distinction: "fire protection" (fire protection), capable of "fire protection" (fire protection au feu), "flame retardant", "delay and/or avoidance of flame spread" or "flame resistance". All these terms define compounds having the ability to make objects safe in the event of an explosion or fire, especially after overheating.

In the following, the expressions "between", "from.

Unless otherwise indicated, the expression "component un (including or including …)" should be understood as being synonymous with "component au moins un (including or including at least one or at least one …)".

Drawings

FIG. 1 is a schematic illustration of an electric or hybrid propulsion system.

Detailed Description

Composition comprising a metal oxide and a metal oxide

As mentioned above, the composition according to the invention comprises at least one base oil or at least one hydrocarbon-based fluid with a boiling point greater than or equal to 50 ℃.

More particularly, the composition according to the invention has kinematic viscosities, measured at 100 ℃ according to the standard ASTM D445, of between 2 and 8mm²S, preferably between 3 and 7mm²Is between/s.

Base oil

The composition according to the invention uses at least one base oil, in particular a fluid base formed from one or more base oils, having a viscosity, measured at 100 ℃ according to the standard ASTM D445, of from 1.5 to 8mm²S, in particular from 1.5 to 6.1mm²S, more particularly from 1.5 to 4.1mm²S, even more particularly from 1.5 to 2.1mm²Kinematic viscosity in/s.

This base oil may be a mixture of base oils, i.e. a mixture of 2, 3 or 4 base oils.

Hereinafter, the term "fluid base" is used to indicate a fluid base having a kinematic viscosity, measured at 100 ℃ according to the standard ASTM D445, of from 1.5 to 8mm²A base oil or a mixture of base oils.

The base oil used in the cooling composition according to the invention may be chosen from oils of mineral or synthetic origin belonging to groups I to V according to the categories defined in the API classification (or their equivalents according to the ATIEL classification) (shown in table a below) or mixtures thereof, provided that the oil or oil mixture has the desired viscosity as described above.

TABLE A

Mineral base oils include all types of base oils obtained by: crude oil is distilled at atmospheric pressure and vacuum, and then subjected to refining operations such as solvent extraction, desalting (lysophatage), solvent deparaffinization, hydrotreating, hydrocracking, hydroisomerization, and hydrofinishing.

Mixtures of synthetic and mineral oils, which may be of biological origin, may also be used.

There is generally no restriction on the use of different base oils for the preparation of the compositions according to the invention, except that they are intended to meet the above-mentioned viscosity criteria, but should also have properties suitable for use in the propulsion system of an electric or hybrid vehicle, in particular the viscosity index, the sulphur content or the oxidation resistance.

According to one embodiment, the one or more base oils of the composition according to the invention are hydrocarbon-based oils, preferably alkanes.

Still according to this embodiment, the one or more base oils may be selected from alkanes comprising at least 8 carbon atoms, such as 8 to 22 carbon atoms, preferably 15 to 22 carbon atoms. For example, it may be C₈-C₂₂Preferably C₁₅-C₂₂An alkane.

The base oil of the composition according to the invention may 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 containing from 2 to 8 carbon atoms, in particular from 2 to 4 carbon atoms.

PAOs for use as base oils are obtained, for example, from monomers containing from 4 to 32 carbon atoms, for example, from octene or decene.

The weight average molecular weight of the PAO can vary considerably. Preferably, the PAO has a weight average molecular weight of less than 600 Da. The PAO may also have a weight average molecular weight of from 100 to 600Da, from 150 to 600Da, or even from 200 to 600 Da.

For example, those used within the scope of the present invention have a kinematic viscosity, measured at 100 ℃ according to the standard ASTM D445, of from 1.5 to 8mm²PAO/s is sold under the trade name Ineos162、164、166 and168, and sold.

Esters of carboxylic acids and alcohols are, for example, diesters of the formula (II):

R^a-C(O)-O-([C(R)₂]_n-O)_s-C(O)-R^b

(I)

wherein:

r represents, independently of one another, a hydrogen atom or a linear or branched (C)₁-C₅) Alkyl, in particular methyl, ethyl or propyl, especially methyl;

-s has a value of 1, 2, 3, 4, 5 or 6;

-n has a value of 1, 2 or 3; it is understood that when s is different from 1, n may be the same or different; and is

-R^aAnd R^bIdentical or different, independently of one another, represent a linear linkage having from 6 to 18 carbon atomsA saturated or unsaturated, linear or branched hydrocarbyl group of (a).

Preferably, when s and n are identical and equal to 2, at least one of the radicals R represents linear or branched (C)₁-C₅) An alkyl group; and when s is 1 and n is 3, at least one of the groups R bonded on the carbon atom in the beta position with respect to the oxygen atom of the ester function represents a hydrogen atom.

Advantageously, the one or more base oils of the composition according to the invention are selected from Polyalphaolefins (PAO).

Preferably, the composition according to the invention comprises a fluid base formed from one or more base oils having a viscosity measured at 100 ℃ according to the standard ASTM D445 of 1.5 and 8mm²Kinematic viscosity between/s.

In other words, the composition according to the invention may be free of a base oil or of a mixture of base oils not meeting the kinematic viscosity standard measured at 100 ℃ according to the standard ASTM D445, in particular free of oils having a viscosity greater than 9mm²A base oil or a mixture of base oils of viscosity/s.

In particular, the base oil may be chosen from alkanes comprising at least 8 carbon atoms, for example from 8 to 22 carbon atoms, preferably from 15 to 22 carbon atoms, or from synthetic oils of the type: esters of carboxylic acids and alcohols, Polyalphaolefins (PAO), and polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides containing 2 to 8 carbon atoms, particularly 2 to 4 carbon atoms.

It is within the ability of the person skilled in the art to adjust the content of the fluid base to be used in the composition according to the invention to achieve the desired viscosity of the composition.

As indicated above, the fluid base provides the lubricating and cooling potential of the composition according to the invention. In particular, the fluidity of the base ensures, in particular, good cooling properties when using the composition in contact with the battery of the propulsion system of an electric or hybrid vehicle.

The cooling properties of the composition employed are advantageously further enhanced by the shear forces applied to the composition at the point of injection, which bring the fluid to a viscosity level below that at rest.

In particular, the composition used according to the invention comprises, relative to the total weight of the composition, from 60% to 99.5% by weight, preferably from 70% to 98% by weight, for example from 80% to 99.5% by weight, more preferably from 80% to 98% by weight, advantageously from 90% to 97% by weight, of a compound having a kinematic viscosity, measured at 100 ℃ according to the standard ASTM D445, of from 1.5 to 8mm²A base oil or a mixture of base oils.

Hydrocarbon-based fluids

The cooling composition for a propulsion system of an electric or hybrid vehicle according to the invention may comprise at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃.

According to a particular embodiment of the invention, the hydrocarbon-based fluid has a boiling point between 50 and 350 ℃, in particular between 60 and 250 ℃, even more particularly between 80 and 200 ℃.

Preferably, the hydrocarbon-based fluid according to the invention has a carbon content of biological origin greater than or equal to 90% by weight, with respect to the total weight of the hydrocarbon-based oil.

In the sense of the present invention, "hydrocarbon-based fluid" means any fluid comprising saturated or unsaturated linear hydrocarbon molecules, which may also comprise aromatic or cyclic groups, or heteroatoms.

Advantageously, the hydrocarbon-based fluid according to the invention is a hydrocarbon comprising at least 8 carbon atoms, for example 8 to 22 carbon atoms, preferably 15 to 22 carbon atoms. For example, it may be C₈-C₂₂Preferably C₁₅-C₂₂An alkane.

Advantageously, the hydrocarbon-based fluid according to the invention is fully saturated. Preferably, the components of the hydrocarbon-based fluid are selected from isoparaffins comprising 12 to 30 carbon atoms, preferably 13 to 19 carbon atoms and more preferably 14 to 18 carbon atoms.

The cooling composition according to the invention advantageously comprises an isohexadecane weight content of less than or equal to 50%.

According to a particular embodiment of the invention, the hydrocarbon-based fluid comprises linear molecules of alkanes or saturated hydrocarbons having a non-cyclic chain, in particular comprising from 12 to 30 carbon atoms, in a content ranging from 80% to 100% by weight, alternatively from 90% to 100% by weight, for example from 95% to 100% by weight, relative to the total weight of the hydrocarbon-based fluid.

Within the scope of the present invention, "paraffin" means straight-chain hydrocarbons (also referred to as "normal paraffins") and/or branched-chain hydrocarbons (also referred to as "isoparaffins").

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

According to a particular embodiment of the invention, the hydrocarbon-based fluid comprises from 90 to 100% by weight of isoparaffins, a content of n-paraffins ranging from 0 to 10% by weight and a content of carbon of biological origin greater than or equal to 90% by weight, relative to the total weight of the hydrocarbon-based fluid.

The hydrocarbon-based fluid advantageously comprises a content of isoparaffins greater than or equal to 90% by weight, in particular greater than or equal to 95% by weight and even more advantageously greater than or equal to 98% by weight, relative to the total weight of the hydrocarbon-based fluid.

According to one embodiment of the invention, the isoparaffin present in the hydrocarbon-based fluid comprises 12 to 30 carbon atoms, preferably 13 to 19 carbon atoms, even more preferably 14 to 18 carbon atoms.

The hydrocarbon-based fluid advantageously comprises a content of n-paraffins lower than or equal to 10% by weight, preferably lower than or equal to 5% by weight, even more preferably lower than or equal to 2% by weight, with respect to the total weight of the hydrocarbon-based fluid.

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

According to one embodiment, the hydrocarbon-based fluid preferably comprises a content by weight of isoparaffins ranging from 90% to 100% and a content by weight of n-paraffins ranging from 0% to 10%, preferably from 95% to 100% of isoparaffins selected from alkanes comprising from 12 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, more preferably from 12 to 22 carbon atoms.

According to a particular embodiment, the hydrocarbon-based fluid according to the invention comprises a majority, i.e. more than 90% by weight, of molecules having 14 to 18 carbon atoms, such as isoparaffins.

According to another embodiment, the hydrocarbon-based fluid according to the invention comprises from 60 to 95% by weight, preferably from 80 to 98% by weight, of isoparaffins selected from the group consisting of: c₁₅Isoparaffins, C₁₆Isoparaffins, C₁₇Isoparaffins, C₁₈Isoparaffins, and mixtures of two or more thereof.

According to one embodiment, the hydrocarbon-based fluid comprises:

-a total amount of 80-98% by weight, relative to the total weight of the hydrocarbon-based fluid, of isoparaffins having 15 carbon atoms and isoparaffins having 16 carbon atoms, or

-a total amount of 80-98% by weight, relative to the total weight of the hydrocarbon-based fluid, of isoparaffins having 16 carbon atoms, isoparaffins having 17 carbon atoms and isoparaffins having 18 carbon atoms, or

-isoparaffins having 17 carbon atoms and isoparaffins having 18 carbon atoms in a total amount of 80 to 98% by weight relative to the total weight of the hydrocarbon-based fluid.

According to a preferred embodiment of the invention, the hydrocarbon-based fluid comprises a total amount of 80 to 98% by weight of isoparaffins having 17 carbon atoms and of isoparaffins having 18 carbon atoms, relative to the total weight of the hydrocarbon-based fluid.

Examples of preferred hydrocarbon-based fluids according to the present invention are those comprising:

-30-70% by weight of C relative to the total weight of the hydrocarbon-based fluid₁₅Isoparaffin and 30-70 wt% of C₁₆Isoparaffins, preferably from 40 to 60% by weight of C₁₅IsoalkanesHydrocarbons and 35-55% by weight of C₁₆An isoparaffin hydrocarbon,

-5-25% of C relative to the total weight of the hydrocarbon-based fluid₁₅Isoparaffin, 30-70% C₁₆Isoparaffin and 10-40% C₁₇Isoparaffins, preferably 8 to 15% C₁₅Isoparaffin, 40-60% C₁₆Isoparaffin and 15-25% C₁₇An isoparaffin hydrocarbon,

-5-30% of C relative to the total weight of the hydrocarbon-based fluid₁₇Isoparaffin and 70-95% C₁₈Isoparaffins, preferably 10 to 25% C₁₇Isoparaffin and 70-90% C₁₈An isoparaffin.

The hydrocarbon-based fluid preferably comprises a naphthenic compound in an amount of less than or equal to 3% by weight, preferably less than or equal to 1%, more preferably less than or equal to 0.5%, even more preferably less than or equal to 500ppm or even 100ppm or 50 ppm.

According to another preferred embodiment, the hydrocarbon-based fluid comprises an isoparaffin weight content of 90% to 100%, a normal paraffin weight content of 0% to 10% and a naphthenic compound weight content of less than or equal to 1%. Preferably, the hydrocarbon-based fluid comprises an isoparaffin weight content of 95% to 100%, a normal paraffin weight content of 0% to 5% and a naphthenic compound weight content of less than or equal to 0.5%. More preferably, it comprises an isoparaffin content by weight of from 98% to 100%, a normal paraffin content by weight of from 0% to 2% and a naphthenic compound content by weight of less than or equal to 100 ppm.

The hydrocarbon-based fluid is advantageously free of aromatic compounds. "free" means that the content by weight of aromatic compounds is less than or equal to 500ppm, preferably less than or equal to 300ppm, preferably less than or equal to 100ppm, more preferably less than or equal to 50ppm and advantageously less than or equal to 20ppm, for example measured by UV spectroscopy.

The weight content of isoparaffins, normal paraffins, naphthenes and/or aromatics in the hydrocarbon-based fluid may be determined according to methods familiar to those skilled in the art. By way of non-limiting example, mention may be made of the method by gas chromatography.

According to another preferred embodiment, the hydrocarbon-based fluid comprises an isoparaffin content by weight of 90 to 100%, a normal paraffin content by weight of 0 to 10%, a naphthenic compound content by weight of less than or equal to 1% and an aromatic compound content by weight of less than or equal to 500 ppm. Preferably, the hydrocarbon-based fluid comprises a content by weight of iso-paraffins of between 95 and 100%, a content by weight of n-paraffins of between 0 and 5%, a content by weight of naphthenic compounds of less than or equal to 0.5% and a content by weight of aromatic compounds of less than or equal to 300ppm, preferably less than 100ppm, preferably less than 50ppm and advantageously less than 20 ppm. Also preferably, the hydrocarbon-based fluid comprises an isoparaffin weight content of 95 to 100%, a normal paraffin weight content of 0 to 5%, and an aromatics weight content of less than or equal to 100 ppm. More preferably, it comprises an isoparaffin content by weight of 98 to 100%, a normal paraffin content by weight of 0 to 2%, a naphthenic compound content by weight of less than or equal to 100ppm and an aromatic compound content by weight of less than or equal to 100 ppm.

The hydrocarbon-based fluids also preferably have an extremely low weight content of sulfur-containing compounds, typically less than or equal to 5ppm, preferably less than or equal to 3ppm, and more preferably less than or equal to 0.5ppm, which is too low to be detected with conventional low sulfur content analyzers.

The hydrocarbon-based fluid also preferably has a flash point greater than or equal to 110 ℃, preferably greater than or equal to 120 ℃, more preferably greater than or equal to 140 ℃ according to standard EN ISO 2719. High flash points, typically greater than 110 ℃, make it possible in particular to overcome safety problems during storage and transport by avoiding, on the one hand, an excessively sensitive flammability of the hydrocarbon-based fluid.

The hydrocarbon-based fluid also preferably has a vapor pressure less than or equal to 0.01kPa at 20 ℃.

According to one embodiment, the hydrocarbon-based fluid also preferably has a flash point greater than or equal to 110 ℃ according to standard EN ISO 2719 and a vapor pressure less than or equal to 0.01kPa at 20 ℃. Preferably, the hydrocarbon-based fluid has a flash point greater than or equal to 120 ℃ and a vapor pressure less than or equal to 0.01kPa at 20 ℃. More preferably, it has a flash point of greater than or equal to 140 ℃ and a vapor pressure of less than or equal to 0.01kPa at 20 ℃.

The hydrocarbon-based fluid has a boiling point, flash point and vapor pressure such that flammability, odor and volatility problems are overcome.

The hydrocarbon-based fluid also preferably has a kinematic viscosity at 40 ℃ according to standard EN ISO 3104 of less than or equal to 5cSt, preferably less than or equal to 4cSt, more preferably less than or equal to 3.5 cSt.

Method for obtaining hydrocarbon-based fluids：

Such hydrocarbon-based fluids may be obtained in the following manner. The hydrocarbon-based fluid according to the invention is a hydrocarbon-based fraction derived from biomass conversion.

In the context of the present invention, "derived from biomass conversion" refers to the hydrocarbon-based fraction produced from a feedstock of biological origin.

Preferably, the hydrocarbon-based fraction of biological origin is obtained by a process comprising Hydrodeoxygenation (HDO) and Isomerization (ISO) steps. The Hydrodeoxygenation (HDO) step results in the breakdown of the structure of the bio-ester or triglyceride component, elimination of oxygen-, phosphorus-and sulfur-containing compounds, and hydrogenation of olefinic bonds. The product obtained from the hydrodeoxygenation reaction is then isomerized. The fractionation step may preferably follow the hydrodeoxygenation and isomerization steps. Advantageously, the fraction of interest is then subjected to a hydrotreatment, followed by a distillation step, in order to obtain the desired specifications of the hydrocarbon-based fluid according to the invention.

This HDO/ISO process is carried out on a raw biological feedstock, also called biomass or feedstock of biological origin, selected from vegetable oils, animal fats, fish oils and mixtures thereof. Suitable feedstocks of biological origin are, for example, rapeseed oil, canola oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, animal fats, such as tallow, recycled food fats, feedstocks obtained from genetic engineering, and biological feedstocks produced from microorganisms, such as algae and bacteria. Condensation products, esters or other derivatives obtained from the original biological material may also be used as starting materials.

Preferably, the starting material of biological origin is an ester or triglyceride derivative. This material is first subjected to a Hydrodeoxygenation (HDO) step to break down the structure of the ester or triglyceride component, with concomitant hydrogenation of the olefinic bonds while eliminating oxygen-, phosphorus-and sulfur-containing compounds. This Hydrodeoxygenation (HDO) step of the feedstock of biological origin is followed by isomerization of the product thus obtained, resulting in branching of the hydrocarbon-based chains and improving the properties of the paraffins at low temperatures.

During the HDO step, hydrogen and the biologically derived feedstock are passed over the hydrodeoxygenation catalyst bed simultaneously or in countercurrent. During the HDO step, the pressure and temperature were 20-150 bar and 200-500 ℃ respectively. Conventional and known hydrodeoxygenation catalysts are used in this step. Optionally, the biologically derived feedstock may be prehydrogenated under mild conditions to avoid side reactions of the double bonds prior to the HDO step. After the hydrodeoxygenation step, the product obtained from the reaction is subjected to an Isomerization (ISO) step in which a mixture of hydrogen and the product and optionally normal paraffins is passed over an isomerization catalytic bed, simultaneously or in countercurrent. During the ISO step, the pressure and temperature were 20-150 bar and 200-500 ℃. Conventional and known isomerization catalysts are used in this step.

Additional secondary processes (e.g., intermediate mixing operations, trapping operations, or other processes of this type) may also be performed.

The product obtained from the HDO/ISO step may optionally be fractionated to obtain a fraction of interest.

Various HDO/ISO methods are described in the literature. Patent application WO 2014/033762 describes a process comprising a prehydrogenation step, a Hydrodeoxygenation (HDO) step and an isomerization step (carried out in countercurrent). Patent application EP1728844 describes a process for the production of hydrocarbon-based compounds from a mixture of compounds of plant and animal origin. This process comprises a step of pre-treating the mixture to enable removal of contaminants such as alkali metal salts, followed by a Hydrodeoxygenation (HDO) step and an isomerization step. Patent application EP2084245 describes a process for producing a mixture of hydrocarbon radicals that can be used as diesel or in a diesel composition, by: hydrodeoxygenation of a mixture of biological origin comprising fatty acid esters, optionally mixed with free fatty acids (for example vegetable oils such as sunflower, rapeseed, canola, palm or pine oils); followed by hydroisomerization over a specific catalyst. Patent application EP2368967 describes such a process and the products obtained by this process. Patent application WO2016/185046 describes a process for obtaining a hydrocarbon-based fluid for use according to the present invention, wherein the hydrocarbon-based fluid is obtained by a catalytic hydrogenation process of deoxygenated and/or isomerized feedstock of biological origin at a temperature ranging from 80 ℃ to 180 ℃ and at a pressure ranging from 50 bar to 160 bar. Such a method is advantageously used in the context of obtaining a hydrocarbon-based fluid according to the invention.

Advantageously, the feedstock of biological origin comprises less than 15ppm, preferably less than 8ppm, preferably less than 5ppm, more preferably less than 1ppm of sulphur, according to standard EN ISO 20846. Ideally, the feedstock does not contain any sulfur as a feedstock of biological origin.

A pre-fractionation step may be performed prior to the hydrotreating step. A narrower fraction at the inlet of the hydrogenation unit enables a narrower fraction to be obtained at the outlet of the unit. In practice, the pre-fractionated fraction has a boiling point between 220 and 330 ℃ and the non-pre-fractionated fraction has a boiling point typically between 150 and 360 ℃.

The deoxygenated and isomerized feedstock obtained from the HDO/ISO process is then hydrogenated.

The hydrogen used in the hydrogenation unit is typically highly purified hydrogen. The term "highly purified" refers to hydrogen having a purity of, for example, greater than 99%, although other grades of hydrogen may also be used.

The hydrogenation step is carried out with the aid of a catalyst. The hydrogenation type catalyst may be a bulk catalyst or a supported catalyst and may comprise the following metals: nickel, platinum, palladium, rhenium, rhodium, nickel tungstate, nickel-molybdenum, cobalt-molybdenum. The support may be silica, alumina, silica-alumina or zeolite.

Preferred catalysts are those based on nickel on an alumina support and having a specific surface area of 100-200m²Catalyst per gram, or bulk catalyst based on nickelAn oxidizing agent. The hydrogenation conditions are typically as follows:

-pressure: 50-160 bar, preferably 80-150 bar, more preferably 90-120 bar;

-temperature: 80-180 ℃, preferably 120-160 ℃, more preferably 150-160 ℃;

-space-time velocity (VVH): 0.2-5hr-1, preferably 0.4-3hr-1, more preferably 0.5-0.8 hr-1;

-treatment rate by hydrogen: the above conditions are adapted and may be up to 200Nm 3/ton of feedstock to be treated.

The temperature in the reactor is generally between 150 and 160 ℃, the pressure is about 100 bar and the hourly space velocity is about 0.6hr-1, the treat rate being adjusted according to the quality of the feedstock to be treated and the parameters of the first hydrogenation reactor.

The hydrogenation may be carried out in one or more reactors in series. The reactor may comprise one or more catalytic beds. The catalytic bed is usually a fixed catalytic bed.

The hydrogenation process preferably comprises two or three reactors, preferably three reactors, and more preferably is carried out in three reactors in series.

The first reactor enables capture of sulfur-containing compounds and hydrogenation of substantially all unsaturated compounds and up to about 90% of aromatic compounds. The product obtained from the first reactor is substantially free of any sulphur-containing compounds. In the second stage, i.e. in the second reactor, the hydrogenation of the aromatics is continued and thus up to 99% of the aromatics are hydrogenated.

The third stage in the third reactor is a refining stage which makes it possible to obtain an aromatic content of less than or equal to 500ppm, preferably less than or equal to 300ppm, preferably less than or equal to 100ppm, more preferably less than or equal to 50ppm, ideally less than or equal to 20ppm, even in the case of products with a high boiling point, for example greater than 300 ℃.

Reactors comprising two or three or more catalytic beds may be used. The catalyst may be present in variable or substantially equal amounts in each reactor; the amount by weight for three reactors may be, for example, 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 more preferably 0.10-0.20/0.20-0.32/0.48-0.70.

Instead of three reactors, one or two hydrogenation reactors may also be used.

The first reactor may also consist of two reactors used alternately. This mode of operation allows in particular a facilitated loading and unloading of the catalyst: when the first reactor contains a first saturated catalyst (substantially all of the sulfur is trapped on and/or in the catalyst), it must be replaced periodically.

It is also possible to use a single reactor in which two, three or more catalytic beds are installed.

It may be necessary to insert a quench tank (for quenching the reaction) in the recirculation system or between the reactors to cool the effluent from one reactor to another or from one catalytic bed to another in order to control the temperature and hydrothermal balance of each reactor. According to a preferred embodiment, no cooling or quenching intermediates are present.

According to one embodiment, the product obtained from the process and/or the separated gases are at least partially recycled to the system for feeding the hydrogenation reactor. This dilution helps to keep the exotherm of the reaction within controlled limits, particularly in the first stage. This recycling also allows heat exchange prior to the reaction and also better temperature control.

The effluent of the hydrogenation unit comprises mainly hydrogenated products and hydrogen. Flash separators are used to separate a vapor phase effluent (primarily residual hydrogen) and a liquid phase effluent (primarily hydrogenated hydrocarbon fraction). The process can be performed using three flash separators, one at high pressure, one at intermediate pressure, and one at low pressure very close to atmospheric pressure.

The hydrogen collected at the top of the flash separator may be recycled to the hydrogenation unit at different levels in the system for feeding the hydrogenation unit or in the hydrogenation unit between the reactors.

According to one embodiment, the final product is isolated at atmospheric pressure. Which is then directly supplied to the vacuum fractionation unit. Preferably, the fractionation will be carried out at a pressure of 10-50 mbar and more preferably at about 30 mbar.

This fractionation may be performed so that various hydrocarbon-based fluids may be withdrawn from the fractionation column at the same time, and their boiling points may be predetermined.

By adjusting the feedstock by means of its initial and final boiling points, the hydrogenation reactor, separator and fractionation unit can thus be directly connected without the use of intermediate tanks. This integration of hydrogenation and fractionation allows for optimized heat integration while reducing equipment count and saving energy.

The hydrocarbon-based fluid according to the invention, having a carbon content of biological origin greater than or equal to 90% by weight relative to the total weight of the hydrocarbon-based oil, is ideally obtained from the treatment of a feedstock of biological origin. The carbon source of the biological material is derived from photosynthesis of the plant and thus from atmospheric CO₂. These are based on CO₂The degradation of the material (the term "degradation" also means burning/incineration at the end of life) therefore does not contribute to warming, since there is no increase in carbon released into the atmosphere. Thus, CO on biological materials₂The evaluation is significantly better and helps to reduce the carbon footprint of the obtained product (only manufacturing energy should be considered). Instead, it is also degraded to CO₂Will contribute to increasing CO₂And thus contribute to global warming. Thus, the hydrocarbon-based fluids used in accordance with the present invention will have a better carbon footprint than compounds obtained from fossil sources.

The term "biochar" means that the carbon is of natural origin and is derived from biological material, as indicated below. The biocarbon content and the biomaterial content are terms representing the same value. A renewable source of material or biomaterial is an organic material in which the carbon is derived from CO that has recently (on a human time scale) been fixed by photosynthesis in the atmosphere₂. Of biological material (100% carbon of natural origin)¹⁴C/¹²C isotope ratio of more than 10^-12And is usually about 1.2X 10^-12And the ratio of the fossil materials is zero. In particular, the method of manufacturing a semiconductor device,¹⁴isotope of CFormed in the atmosphere and then integrated by photosynthesis, requiring a time scale of at most several decades.¹⁴The half-life of C was 5730 years. Thus, the material obtained from photosynthesis (i.e. usually plants) must have the largest size¹⁴C isotope content.

The biomaterial or biocarbon content is determined according to standard ASTM D6866-12, method B (ASTM D6866-06) and ASTM D7026 (ASTM D7026-04). Standard ASTM D6866 relates to "determination of biobased content of natural range materials using radiocarbon and isotope ratios by mass spectrometry", while standard ASTM D7026 relates to "sampling and results reporting for determination of biobased content by carbon isotope analysis". The second standard mentions the first case in its first paragraph.

The first standard describes a method for measuring a sample¹⁴C/¹²C ratio and comparison with a reference sample of 100% renewable origin¹⁴C/¹²The C ratio is compared to derive the relative percentage of C of renewable origin in the sample. The criterion is based on¹⁴C year measurement same concept, but no year measurement formula was applied. The ratio thus calculated is expressed as "pMC" (percentage of modern carbon). If the material to be analyzed is a mixture of biological and fossil materials (without radioisotopes), the pMC value obtained is directly related to the amount of biological material present in the sample. For¹⁴The reference value for year C is the value measured from the 1950 s. This year was chosen because of the atmospheric nuclear test, after which time a large amount of isotope was introduced into the atmosphere. The reference value in 1950 corresponds to a pMC value of 100. The current value to be used is about 107.5 (corresponding to a correction factor of 0.93) in view of the thermonuclear test. Thus, the radioactive carbon label of the current plant is 107.5. The labeling of 54pMC and 99pMC thus corresponds to 50% and 93% respectively of the amount of biological material in the sample.

The hydrocarbon-based fluid according to 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%.

According to one embodiment, the invention usesOf hydrocarbon-based fluids¹⁴C/¹²The isotope ratio of C is 1.15-1.2X 10¹²。

In addition to a particularly high content of biological material, the hydrocarbon-based fluids according to the invention have a particularly good biodegradability. Biodegradation of organic chemical products refers to the reduction of the complexity of a compound by the metabolic activity of microorganisms. Under aerobic conditions, microorganisms convert organic matter into carbon dioxide, water, and biomass. The OCDE 306 method is used to evaluate the biodegradability of individual substances in seawater. According to this method, the hydrocarbon-based fluid has a 28-day biodegradability of at least 60%, preferably at least 70%, more preferably at least 75% and advantageously at least 80%.

The OCDE 306 process is as follows:

the closed vial method consists in dissolving a predetermined amount of the test substance in a control medium at a concentration conventionally comprised between 2 and 10mg/L (optionally using one or more concentrations). The solution was stored in a filled closed bottle at a constant temperature of 15-20 ℃ protected from light. Degradation was monitored by oxygen analysis over a 28 day period. 24 bottles (8 bottles of test substance, 8 bottles of reference compound, 8 bottles of nutrient) were used. All analyses were performed on several bottles. Dissolved oxygen measurements were performed at least four times (days 0, 5, 15 and 20) using chemical or electrochemical methods.

According to a particular embodiment of the invention, the hydrocarbon-based fluid comprises:

-a weight content of isoparaffin ranging from 95% to 100% and preferably from 98% to 100%, relative to the total weight of the hydrocarbon-based fluid, and

-a weight content of n-paraffins lower than or equal to 5% and preferably lower than or equal to 2%, relative to the total weight of the hydrocarbon-based fluid; and

-a content by weight of naphthenic compounds lower than or equal to 0.5% and preferably lower than or equal to 100ppm with respect to the total weight of the hydrocarbon-based fluid; and

-a weight content of aromatic compounds lower than or equal to 300ppm, preferably lower than or equal to 100ppm, more preferably lower than or equal to 50ppm and advantageously lower than or equal to 20ppm, with respect to the total weight of the hydrocarbon-based fluid.

According to a particular embodiment of the invention, the hydrocarbon-based fluid has a weight content of isoparaffin ranging from 98% to 100% relative to the total weight of the hydrocarbon-based fluid, and a kinematic viscosity at 40 ℃ lower than or equal to 5cSt, preferably lower than or equal to 4cSt, and preferably lower than or equal to 3.5 cSt.

Advantageously, the composition used according to the invention comprises from 80% to 99.5% by weight, even more preferably from 80% to 98% by weight, advantageously from 90% to 97% by weight, of at least one base oil or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃, relative to the total weight of the composition.

Flame retardant

In the context of the present invention, at least one flame retardant is incorporated into a cooling composition of a propulsion system of an electric or hybrid vehicle, which corresponds to formula (I)

R_F-L-R_H (I)

Wherein

R_FIs a perfluorinated or partially fluorinated group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

R_His a hydrocarbyl group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16, carbon atoms, and

l is a linking group.

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%.

Applicants do not wish to be bound by any theory, and describe that the presence of at least one flame retardant of formula (I) is suitable for forming micelles in the cooling composition. In the case where heating is easily caused by flame, the micelles will exist on the surface of the composition, and thus can oppose the flame.

According to a particular embodiment, the radical R_FContaining from 1 to 22, preferably from 1 to 20 and more particularly from 1 to 16 carbon atoms. Said group being optionally substituted by 1 to 4 hetero atoms selected from nitrogen and oxygen atomsThe atom is interrupted. This group may also be linear or branched.

Advantageously, it is perfluorinated or partially fluorinated (C)₁-C₁₆) An alkyl group, optionally interrupted by one or two heteroatoms selected from nitrogen atoms and oxygen atoms.

Such a radical R_FFor example, it may be selected from the following groups:

·CF₃(CF₂)_m-，

·C(CF₃)₃(CF₂)_m-，

·(CF₃)₂CF(CF₂)_m-，

·(CF₃)₂CF-, and

·(CF₃)CF₂-，

·(CF₃)(CF₂)₃-，

wherein m is an integer which may be from 1 to 15 and m is an integer from 0 to 14.

These examples are not limiting.

According to another particular embodiment, the radical R_HContaining from 1 to 22 carbon atoms, more particularly from 8 to 22 carbon atoms. According to a particular embodiment, this radical R_HMay contain 1 to 4 hetero atoms selected from nitrogen atoms and oxygen atoms. Furthermore, this group may be linear or branched. It may also be saturated or may contain 1-4 unsaturations.

According to another embodiment, the radical R_HIt may preferably comprise 3 to 22 carbon atoms, more preferably 3 to 18 carbon atoms, for example 5 to 15 carbon atoms, or even 10 to 15 carbon atoms.

Advantageously, it is (C)₁-C₁₅) Alkyl, especially (C)₃-C₁₅) Alkyl or (C)₂-C₁₅) Alkenyl radicals optionally substituted by a hydrocarbyl ring such as (C)₃-C₆) Cycloalkyl, phenyl or benzyl.

Such a radical R_HMay be selected in particular from the following groups, but is not limited thereto:

·-(CH₂)_nCH₃，

·-(CH₂)_pC₆H₄，

·-(CH₂)_qO(CH₂)_rCH₃and are and

·-(CH₂)_sC＝C(CH₂)_tCH₃

where n is an integer which may be from 1 to 21, for example from 2 to 21, especially from 7 to 21, p is from 1 to 16, especially from 2 to 10, q and r are independently from 1 to 16, where q + r is less than or equal to 21 and advantageously greater than 7, s and t are independently from 1 to 16, where s + t is less than or equal to 19 and advantageously greater than 5.

The linking group L may in particular be selected from the following divalent groups: -CH₂-, -CH ═ CH-, -O-, -S-or-PO₄-。

According to a particular embodiment, the flame retardant may be chosen from compounds of formula (I) in which R is_FIs perfluorinated or partially fluorinated (C)₂-C₁₂) Alkyl radical, R_HIs (C)₁-C₁₂) Alkyl, especially (C)₃-C₁₂) Alkyl, especially (C)₆-C₁₂) Alkyl or (C)₂-C₁₂) Alkenyl, especially (C)₆-C₁₂) Alkenyl, said radical being optionally substituted by a hydrocarbyl ring such as (C)₃-C₆) Cycloalkyl, phenyl or benzyl, and said groups may be interrupted by one or two heteroatoms selected from nitrogen and oxygen, and L is selected from-CH₂A linking group of-CH-and-O-.

In the context of the present invention it is understood 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.

In the context of the present invention, the following terms are defined as follows:

-“(C₁-C_x) Alkyl "means a linear or branched saturated hydrocarbyl chain containing 1 to x carbon atoms, e.g. (C)₁-C₁₂) An alkyl group. Non-limiting examples that may be mentioned include the following groups: methyl, ethyl, 1-propyl, 2-propyl, butyl, pentylHexyl, heptyl and decyl;

-“(C₂-C_x) Alkenyl "means a linear or branched unsaturated hydrocarbyl chain containing 2 to x carbon atoms, e.g. (C)₂-C₁₂) An alkyl group. Non-limiting examples that may be mentioned include the following groups: ethenyl, propenyl, butenyl, pentenyl, hexenyl, and decenyl;

-“(C₃-C₆) Cycloalkyl "refers to a saturated cyclic hydrocarbyl chain. Non-limiting examples that may be mentioned include the following groups: cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

According to the invention, the flame retardant(s) of formula (I) may be present in a content ranging from 0.5% to 40% by weight, from 2% to 30% by weight, even more particularly from 2% to 20% by weight and advantageously from 3% to 10% by weight, relative to the total weight of the composition according to the invention.

For the formulation of the composition according to the invention, any method known to the skilled person can be used for this addition to the hydrocarbon-based fluid using at least one flame retardant.

Fluorinated compounds

The cooling composition according to the invention comprises at least one fluorinated compound having a boiling point in the range of 50 to 250 c, preferably 55 to 120 c.

Preferably, the fluorinated compound having a boiling point of from 50 to 250 ℃, preferably from 55 to 120 ℃, is different from the flame retardant of formula (I) as defined above.

In the context of the present invention, the fluorinated compound refers to an organic compound comprising at least 5 fluorine atoms.

According to a particular embodiment of the invention, the fluorinated compound comprises at least 8 fluorine atoms, even at least 10, even more at least 12 fluorine atoms.

According to another particular embodiment, the fluorinated compounds according to the invention are perfluorinated compounds, i.e. compounds in which each hydrogen atom has been replaced by a fluorine atom.

According to a particular embodiment of the invention, the fluorinated compound is selected from perfluorooctane, perfluorocyclohexane and mixtures thereof.

According to one embodiment of the invention, the fluorinated compound may be a mixture of fluorinated compounds. Thus, in the context of the present invention, when reference is made to a fluorinated compound, it may in fact be a mixture of fluorinated compounds.

Without being bound by any theory, the inventors describe that fluorinated compounds having this particular boiling point range enable the micelles formed by the flame retardant of formula (I) as described before to break in the event of overheating of the battery, thereby ensuring increased contact between the fluorinated components of the flame retardant of formula (I) as described before. In other words, when the battery is overheated due to an abnormal rise in heat transfer temperature, the fluorinated compound having a boiling point of 50 to 250 ℃ is converted into a gas, so that the flame retardant migrates to the surface of the composition, which is in contact with the battery or power electronics in particular, imparting the intended flame retardant property.

The fluorinated compound may be present in the composition according to the invention in a content ranging from 0.01% to 20% by weight, in particular from 0.1% to 10% by weight, even more preferably from 0.2% to 5% by weight, relative to the total weight of the composition.

According to one embodiment of the invention, the cooling composition comprises from 2% to 30% by weight, preferably from 2% to 20% by weight and advantageously from 3% to 10% by weight, of at least one flame retardant of formula (I) as defined above, and from 0.01% to 20% by weight, in particular from 0.1% to 10% by weight and preferably from 0.2% to 5% by weight, of at least one fluorinated compound having a boiling point of from 50 to 250 ℃, relative to the total weight of the composition.

According to yet another embodiment of the invention, the composition comprises at least one flame retardant of formula (I) and at least one fluorinated compound having a boiling point of 50-250 ℃, wherein the mass ratio flame retardant/fluorinated compound is from 0.2 to 200, preferably from 0.5 to 50.

According to a particular embodiment of the invention, the fluorinated compound having a boiling point of between 50 and 250 ℃ is different from the flame retardant corresponding to formula (I) and the base oil or hydrocarbon-based fluid having a boiling point of greater than or equal to 50 ℃ is present in the composition in a content of greater than or equal to 80% by weight, preferably between 80% and 99.5% by weight, with respect to the total weight of the composition.

According to a particular embodiment of the invention, the composition comprises:

(i) from 60% to 99.5% by weight, preferably from 70% to 98% by weight, even more preferably from 80% to 98% by weight and advantageously from 90% to 97% by weight, of at least one base oil or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃, relative to the total weight of the composition;

(ii) 2% to 30% by weight, preferably 2% to 20% by weight and advantageously 3% to 10% by weight of a flame retardant corresponding to formula (I), relative to the total weight of the composition; and

(iii) from 0.01% to 20% by weight, preferably from 0.1% to 10% by weight and even more particularly from 0.2% to 5% by weight, of a fluorinated compound having a boiling point of from 50 to 250 ℃, relative to the total weight of the composition.

The cooling composition according to the invention may also comprise at least one free radical inhibitor.

Such free radical inhibitors are known per se to the person skilled in the art and can have various chemical properties and in particular can belong to various chemical families.

For the formulation of the composition according to the invention, any method known to the person skilled in the art can be used for this addition to the fluid.

Among the radical inhibitors, mention may in particular be made of phosphorus-containing radical inhibitors.

Among the phosphorus-containing free radical inhibitors, the distinction is made between compounds in which phosphorus is p (v) or pentavalent phosphorus or compounds in which phosphorus is p (iii) or trivalent phosphorus.

Among these pentavalent phosphorus forms of compound p (v), mention may be made in particular of the family of phosphates, in particular triethyl phosphate, trimethyl phosphate, optionally fluorinated alkyl phosphates, or aryl phosphates.

As fluorinated alkylphosphate esters, mention may in particular be made of tris (2,2, 2-trifluoroethyl) phosphate.

As aryl phosphates, mention may in particular be made of triphenyl phosphate, tricresyl phosphate and trixylenyl phosphate.

Among these compounds in the form of P (V), mention may be made in particular of the phosphazene family. Among this family, which is characterized in that it represents at least one double bond comprised between a pentavalent phosphorus atom and a nitrogen atom, cyclic compounds are preferably chosen. Mention may in particular be made of hexamethoxycyclotriphosphazene.

Among these compounds which are present in the form of trivalent phosphorus P (III), mention may be made in particular of the phosphite family. Among this family, mention may be made in particular of tris (2,2, 2-trifluoroethyl) phosphite.

In addition to the flame retardants of the formula (I) described above, the cooling composition according to the invention may also comprise at least one further flame retardant.

Among these additional flame retardants, halogenated compounds other than fluorinated compounds may be specifically mentioned.

The proportion of the various ingredients of the composition, in particular the fluid base, the flame retardant of formula (I) as defined previously and optionally the free radical inhibitor and/or the further flame retardant, can be adjusted by the person skilled in the art to correspond to the desired viscosity of the invention and, optionally, the density of the composition.

The one or more flame retardants of formula (I) as defined before, and optionally the radical inhibitor and/or the further flame retardant may be incorporated directly into the hydrocarbon-based fluid according to the invention.

According to a particular embodiment, the cooling composition according to the invention comprises at least one hydrocarbon-based fluid comprising a content of isoparaffins greater than or equal to 90% by weight, in particular greater than or equal to 95% by weight, even more advantageously greater than or equal to 98% by weight, relative to the total weight of the hydrocarbon-based fluid, at least one flame retardant of formula (I) as defined previously and optionally at least one phosphorus-containing radical inhibitor.

According to a particular embodiment, the cooling composition according to the invention comprises at least one hydrocarbon-based fluid having a weight content of isoparaffins ranging from 98% to 100% relative to the total weight of the hydrocarbon-based fluid and a kinematic viscosity at 40 ℃ of less than or equal to 5cSt, preferably less than or equal to 4cSt and preferably less than or equal to 3.5cSt, at least one flame retardant of formula (I) as defined above and optionally at least one phosphorus-containing radical inhibitor (in particular those as described above).

Alternatively, the composition according to the invention may also comprise one or more additives, as defined more precisely below.

Other additives

According to a variant of the invention, the cooling composition according to the invention also comprises additives that modify the properties of the base oil.

Additives that may be incorporated into the composition according to the present invention may be selected from detergents, dispersants, antioxidants, pour point improvers, anti-foaming agents and mixtures thereof.

It will be appreciated that the nature and amount of the additives used are selected so as not to affect the combination of cooling capacity and fire-resistance of the composition according to the invention.

The cooling composition according to the invention may comprise at least one antioxidant additive.

The antioxidant additive typically enables the degradation of the composition in use to be delayed. This degradation may be manifested in particular by the formation of deposits, the presence of sludge or an increase in the viscosity of the composition.

The antioxidant additive is particularly useful as a structure-breaking agent or free radical inhibitor for hydroperoxides. Among the usual antioxidant additives, mention may be made of phenolic antioxidant additives, aminic antioxidant additives, phosphorus-sulfur antioxidant additives. Some of these antioxidant additives (e.g., phosphorus sulfur antioxidant additives) may be ash generators. The phenolic antioxidant additives may be ashless, or may be in the form of neutral or basic metal salts. The antioxidant additive may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols containing thioether bridges, diphenylamines, substituted by at least one C₁-C₁₂Alkyl group substituted diphenylamines, N, N' -dialkyl-aryl diamines, and mixtures thereof.

According to the invention, the sterically hindered phenol is preferably chosen from compounds comprising a phenol group whose carbon bearing an alcohol function is substituted by at least one C at least one carbon ortho to the carbon bearing the alcohol function₁-C₁₀Alkyl radical, preferably C₁-C₆Alkyl radical, preferably C₄Alkyl groups, preferably tert-butyl groups.

Aminated compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of aminating compounds are aromatic amines, e.g. of the formula NR⁴R⁵R⁶Wherein R is⁴Represents an optionally substituted aliphatic or aromatic radical, R⁵Represents an optionally substituted aromatic radical, R⁶Represents a hydrogen atom, an alkyl group, an aryl group or the formula R⁷S(O)_zR⁸Wherein R is⁷Represents an alkylene group or alkenylene group, R⁸Represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

Sulfurized alkylphenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

Another class of antioxidant additives are copper compounds, such as copper thiophosphates or dithiophosphates, salts of copper and carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonate. Salts, succinic anhydrides or acid salts of copper I and II may also be used.

The cooling composition according to the invention may comprise all types of antioxidant additives known to the person skilled in the art.

Advantageously, the cooling composition according to the invention comprises at least one ashless antioxidant additive.

The cooling composition according to the invention comprises 0.5-2% by weight of at least one antioxidant additive, relative to the total mass of the composition.

The cooling composition according to the invention may also comprise at least one detergent additive (additif detergent).

Detergent additives generally enable the formation of deposits on the surface of metal parts to be reduced by dissolving the byproducts of oxidation and combustion.

Detergent additives useful in cooling compositions according to the present invention are generally known to those skilled in the art. Detergent additives may be anionic compounds comprising a lipophilic long hydrocarbon chain and a hydrophilic top end. The relevant cation may be a metal cation of an alkali metal or alkaline earth metal.

The detergent additive is preferably selected from the group consisting of alkali or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates and phenates. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

These metal salts generally contain a stoichiometric or excess (and thus an amount greater than stoichiometric) of the metal. This thus relates to overbased detergent additives; the excess metal to impart overbased character to the detergent additive is then typically in the form of an oil-insoluble metal salt, such as a carbonate, hydroxide, oxalate, acetate, glutamate, preferably a carbonate.

The cooling composition according to the invention may comprise 2-4% by weight of detergent additives, relative to the total mass of the composition.

The cooling composition according to the invention may also comprise at least one pour point depressant additive.

Pour point depressant additives generally improve the cold behavior of the composition by slowing the formation of paraffin crystals.

Mention may be made, as examples of pour point depressant additives, of polyalkylmethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes and alkylated polystyrenes.

Furthermore, the cooling composition according to the invention may comprise at least one dispersant.

The dispersant may be selected from Mannich bases, succinimides and derivatives thereof.

The cooling composition according to the invention may, for example, comprise 0.2 to 10% by weight of dispersant, relative to the total mass of the composition.

According to a particular embodiment, the composition according to the invention comprises or consists of:

(i) from 80% to 99.5% by weight, preferably from 80% to 98% by weight and more preferably from 90% to 97% by weight of at least one base oil or at least one hydrocarbon-based fluid having a boiling point greater than or equal to 50 ℃, preferably chosen from hydrocarbons comprising at least 8 carbon atoms, for example from 8 to 22 carbon atoms;

(ii) 0.5% to 40% by weight, preferably 2% to 30% by weight, more preferably 2% to 20% by weight and advantageously 3% to 10% by weight of a flame retardant corresponding to formula (I), in particular wherein R_FIs perfluorinated or partially fluorinated (C)₂-C₁₂) Alkyl radical, R_HIs (C)₆-C₁₂) Alkyl, (C)₆-C₁₂) An alkenyl group, said group optionally being (C)₃-C₆) Cycloalkyl, phenyl or benzyl, and said groups may be interrupted by 1 or 2 heteroatoms selected from nitrogen and oxygen, and L is selected from-CH₂A linker of-CH ═ CH-and-O-;

(iii) 0.01% to 20% by weight, preferably 0.1% to 10% by weight and even more particularly 0.2% to 5% by weight of a fluorinated compound having a boiling point of 50 ℃ to 250 ℃; and

(iv) optionally, from 0.1% to 10% of one or more additives selected from the group consisting of phosphorus-containing free radical inhibitors, detergents, dispersants, antioxidants, pour point improvers, anti-foaming agents, and mixtures thereof;

the amounts are expressed relative to the total weight of the composition.

Applications of

As previously mentioned, the composition according to the invention, thanks to its combined properties in terms of cooling and flame retardancy, can be used both as a cooling fluid for the drive system of an electric or hybrid vehicle (and more particularly for the power electronics and the battery) and as a fluid to delay and/or avoid the propagation of the flame of the battery.

Advantageously, the composition according to the invention is in contact with the battery by immersion or semi-immersion, to play a dual role in its cooling and fire protection for the battery.

The term "immersed" means that all the cells are surrounded by the cooling composition according to the invention. The term "semi-immersed" means that only a portion of the cell is in contact with the composition.

Alternatively still, the cooling composition according to the invention is advantageously in direct contact with the battery by the method described below.

As batteries suitable for use in the propulsion system of electric or hybrid vehicles, mention may be made of Li-ion batteries or nickel-cadmium batteries.

The motor is typically powered by a battery (2). Lithium ion batteries are the most widely used batteries in the field of electric vehicles. The development of increasingly powerful batteries and their smaller size has led to the problem of cooling such batteries. In fact, once the battery exceeds a temperature of about 50-60 ℃, there is a high risk of the battery catching fire or even exploding. It is also desirable to maintain the battery at a temperature greater than about 20-25 c to avoid excessive discharge of the battery and to extend its useful life.

The composition of the invention is thus useful for cooling the battery of an electric or hybrid vehicle and delaying and/or avoiding flame propagation.

The composition according to the invention can be injected under relatively high pressure into the area to be cooled of the propulsion system of an electric or hybrid vehicle, the shear forces generated at the injector making it possible advantageously to reduce the viscosity of the fluid at the injection area with respect to the kinematic viscosity at rest and thus further increase the cooling potential of the composition.

As schematically shown in fig. 1, the propulsion system of an electric or hybrid vehicle comprises, inter alia, an electric motor section (1). This typically includes power electronics (11) connected to the stator (13) and rotor (14).

The stator comprises coils, in particular copper coils, which are supplied with alternating current. This generates a rotating magnetic field. The rotor itself comprises coils, permanent magnets or other magnetic material and is rotated by this rotating magnetic field.

The power electronics (11), the stator (13) and the rotor (14) of the propulsion system (1) are components which have a complex structure and generate a large amount of heat during operation of the electric motor. It is therefore of critical importance to ensure cooling of the motor and power electronics.

The bearing (12) is typically integrated between the stator (13) and the rotor (14).

The drive system of an electric or hybrid vehicle may also comprise a transmission, in particular a reducer (3), which makes it possible to reduce the rotational speed of the motor output and to adapt the speed transmitted to the wheels, so that the speed of the vehicle can be controlled simultaneously.

The invention thus relates to the use of a composition as described previously for cooling batteries and power electronics and for providing fire protection to the propulsion system of an electric or hybrid vehicle and in particular to the battery.

The advantage of the present invention is therefore that it is possible to use a single composition that combines cooling and fire or flame retardant properties as a cooling and fire protection fluid for batteries in electric or hybrid vehicles, while ensuring the cooling function of the power electronics of the electric or hybrid vehicle.

According to a particular embodiment, the composition of the invention plays a lubricating role in addition to its cooling and flame-retardant role. This triple action is achieved in particular when the flame retardant of formula (I) as defined above is used in a base oil as described above. This is because the hydrocarbon-based fluid having a boiling point of 50 ℃ or higher as described above cannot perform a lubricating function.

In other words, according to this embodiment, the composition comprises:

(i) at least one base oil;

(ii) at least one flame retardant corresponding to formula (I)

R_F-L-R_H (I)

Wherein

R_FIs a perfluorinated or partially fluorinated group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms,

R_His a hydrocarbyl group, said group containing in particular from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16, carbon atoms, and

l is a linker; and

(iii) at least one fluorinated compound having a boiling point of 50 ℃ to 250 ℃.

Still according to this particular embodiment, the composition can be used, thanks to its overall performance in terms of lubrication, cooling and flame-retardant, both as a lubricating fluid for engines and transmissions, as a cooling fluid for propulsion systems of electric or hybrid vehicles and more particularly for electric motors, power electronics and batteries, and as a fluid to delay and/or avoid the propagation of flames by the batteries. The invention therefore also relates to the use of a composition as defined above for the lubrication, cooling and safety of the propulsion system of an electric or hybrid vehicle.

Still according to this embodiment, the composition ensures the lubricating and anti-wear functions for the contact member in the electric or hybrid vehicle, and the cooling functions for the engine and power electronics, in addition to the cooling function and the fire prevention function of the battery.

The propulsion system of an electric or hybrid vehicle also comprises a transmission, in particular a reducer (3), which makes it possible to reduce the speed of rotation of the motor output and to adapt the speed transmitted to the wheels, so that the speed of the vehicle can be controlled simultaneously.

The reducer is subjected to high friction stresses and therefore requires adequate lubrication to avoid its excessive rapid deterioration.

Thus, the composition according to this particular embodiment makes it possible to lubricate the transmission, in particular the retarder, in an electric or hybrid vehicle.

The present invention thus relates to the use of a composition as described hereinbefore for cooling batteries, engines and power electronics, for lubricating engines and transmissions and for providing fire protection to propulsion systems of electric or hybrid vehicles and in particular batteries.

In particular, such a composition makes it possible to cool the rotor and/or the stator of the power electronics and/or the electric motor. It also ensures the lubrication of the bearings located between the rotor and the stator of the electric motor of an electric or hybrid vehicle.

Thus, an advantage of this embodiment of the invention is that a single composition that combines cooling and fire or flame retardant properties can be used as a cooling and fire protection fluid for a battery in an electric or hybrid vehicle, while ensuring the lubricating and cooling functions of the propulsion system of the electric or hybrid vehicle as a whole.

The invention also relates to a method for cooling and preventing fires of at least one battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of bringing the 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 in immersing or semi-immersing the battery in said composition or injecting said composition onto the surface of the battery.

All the characteristics and preferences described for the cooling composition according to the invention and its use also apply to this method.

The cooling of the composition according to the invention can be carried out by any method known to the person skilled in the art.

The cell may be statically or cyclically immersed or semi-immersed in the composition.

As examples of direct contact, mention may be made of the cooling by injection, spraying, by spraying or by forming a mist under pressure and by gravity on the battery from the composition according to the invention.

Advantageously, the composition is injected by spraying at a relatively high pressure into the area of the propulsion system to be cooled. Advantageously, the shear forces generated by such injection make it possible to reduce the viscosity of the fluid at the injection zone with respect to the kinematic viscosity at rest and thus further increase the cooling potential of the composition.