Use of Diesters in Compositions for Cooling and / or Lubrication of Electric or Hybrid Vehicles

Abstract

The present invention relates to the use of a composition comprising one or more diesters for cooling and / or lubricating the propulsion system of an electric or hybrid vehicle, each of said diesters being formed between a diol containing 3 to 12 carbon atoms and two linear or branched hydrocarbon chains having 4 to 10 carbon atoms, which are the same or different, and two monocarboxylic acids.

Description

Technical Field

[0001] The present invention relates to the field of compositions for cooling and / or lubricating the propulsion system of electric or hybrid vehicles, and more specifically to the field of compositions for cooling the battery and motor reduction gear, battery and / or power electronics components of electric or hybrid vehicles. More specifically, the present invention aims to propose a cooling composition adapted to its implementation in motors or motor reduction gears, batteries and power electronics components.

Background Art

[0002] Due to the international standards for reducing not only CO2 emissions but also energy consumption, automobile manufacturers have been forced to propose alternative solutions to internal combustion engines.

[0003] One of the solutions identified by automobile manufacturers is to replace the internal combustion engine with an electric motor. Therefore, due to research for reducing CO2 emissions, several automobile companies have developed electric vehicles.

[0004] While hybrid vehicles are equipped with an internal combustion engine and an electric motor as a composite propulsion means, the "electric vehicle" defined by the present invention refers to a vehicle equipped with an electric motor as a sole propulsion means.

[0005] The "propulsion system" defined by the present invention refers to a system equipped with mechanical parts necessary for the propulsion of an electric vehicle. Therefore, the propulsion system more specifically includes an electric motor having a rotor-stator assembly (for speed adjustment only) of a power electronics system, a transmission (also called a reduction gear, and when the reduction gear is connected to the motor, it is called a motor reduction gear), and a battery. Such a battery usually consists of a set of power storage devices called cells.

[0006] Generally, in electric or hybrid vehicles, it is necessary to use a composition to meet the lubrication and / or cooling requirements of various parts of the propulsion system described above.

[0007] More specifically, while the electric propulsion system is operating, it generates heat through the electric motor, the power electronics system, and the battery. Since the amount of heat generated is greater than the amount of heat that is normally dissipated into the environment, cooling must be performed on the engine, the electronic system, and the battery. Generally, cooling is performed on some of the heat-generating components of the propulsion system and / or the heat-sensitive parts of the system, particularly the power electronics system and the battery, in order to prevent them from reaching dangerous temperatures.

[0008] Conventionally, a method of cooling an electric motor with air or water, optionally in combination with glycol, has been known. However, with the advent of engines that are increasingly more powerful and smaller in size, such a cooling method is no longer sufficient. Also, the heat that the battery can generate, particularly during rapid charging, cannot be removed by the conventionally used methods.

[0009] Therefore, alternative methods for cooling and lubricating the propulsion system, more specifically the battery, have recently been proposed.

[0010] As such a method, a lubricating composition that performs both the lubricating and cooling functions has been proposed. Conventionally, lubricating compositions are composed of one or more base oils, and generally, a plurality of additives for promoting the lubricating performance of the base oil, such as friction modifier additives, are attached to the base oil.

[0011] As an example, in the document of International Publication No. WO 2018 / 078290, it is proposed to use a composition containing at least one polyalkylene glycol obtained by polymerization or copolymerization of alkylene oxides containing 2 to 8 carbon atoms to cool and / or lubricate the motor system of an electric vehicle. SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0012] More precisely, the present invention aims to propose a novel composition suitable for the implementation of the present invention for cooling and / or lubricating the propulsion system of an electric or hybrid vehicle, more specifically for cooling a motor or motor reduction gear, a battery and / or power electronics components, or for lubricating, in particular, a motor or motor reduction gear, or even more specifically only a reduction gear.

Means for Solving the Problems

[0013] Therefore, the subject matter of the present invention is the use of a composition comprising one or more diesters for cooling and / or lubricating the propulsion system of an electric or hybrid vehicle, each of said diesters being formed between a diol having 3 to 12 carbon atoms and two linear or branched hydrocarbon chains having 4 to 10 carbon atoms, which are the same or different monocarboxylic acids.

[0014] According to one embodiment, the composition comprises at least 5% by weight, preferably at least 10% by weight, or preferably at least 30% by weight, even more preferably at least 50% by weight, or even at least 70% by weight, or 100% by weight of said diester(s) based on the total weight of the composition.

[0015] Preferably, the composition comprises, based on the total weight of the diester(s) and a base oil different from said diester, - 5 to 95% by weight, preferably 5 to 50% by weight, more preferably 10 to 40% by weight of said one diester or plural diesters, and - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight of one or more base oils different from said diester and comprises.

[0016] According to one embodiment, the composition is used to cool the battery and / or power electronics components of an electric or hybrid vehicle, more specifically a lithium-ion battery or a nickel-cadmium battery.

[0017] Preferably, the diester contains 13 to 25 carbon atoms, preferably 15 to 24 carbon atoms.

[0018] Preferably, the kinematic viscosity of the diester is in the range of 1 to 6 mm 2 / s at 100 °C, preferably in the range of 1 to 4 mm 2 / s.

[0019] Preferably, at least one of the two hydroxyl functional groups of the diol is supported by a primary carbon atom.

[0020] Preferably, the diol is selected from 1,2-propanediol, 1,2-decanediol, and 1,3-alkanediols having 3 to 10 carbon atoms.

[0021] Preferably, the diol is selected from 1,2-propanediol and 1,3-propanediol, and preferably the diol is 1,2-propanediol.

[0022] Preferably, the plurality of monocarboxylic acids are the same or different and contain a linear hydrocarbon chain having 4 to 10 carbon atoms, preferably 5 to 9 carbon atoms.

[0023] Preferably, in addition to the diester(s), the composition contains at least one additive selected from antioxidants, pour point depressants, defoamers, corrosion inhibitors, antiwear agents and / or extreme pressure additives, friction modifiers, detergents, dispersants, and mixtures thereof, more specifically antioxidants, pour point depressants, defoamers, and corrosion inhibitors.

[0024] According to one embodiment of the present invention, the present invention is the use of a composition for cooling and / or lubricating a propulsion system of an electric or hybrid vehicle, wherein the composition comprises - one or more diesters formed between a diol selected from 1,2-decanediol and 1,3-propanediol and two linear or branched monocarboxylic acids having 4 to 10 carbon atoms, which may be the same or different, - a diester formed from 1,2-propanediol and two heptanoic acids, - a diester formed from 1,2-propanediol and two octanoic acids, - a diester formed from 1,2-propanediol and two decanoic acids, - a diester formed from 1,2-propanediol and octanoic acid and decanoic acid, and a composition comprising one or more diesters selected from mixtures thereof relates to the use of.

[0025] Other features, variations and advantages regarding the implementation of the diesters according to the present invention will become clearer upon reading the following description and examples, which are given by way of illustration of the present invention and are not limited thereto.

[0026] Hereinafter, in the text, the expressions "included between... and...", "ranging from... to...", and "varying from... to..." are equivalent unless otherwise specified, and mean that the limit values are included.

[0027] Unless otherwise specified, the expression "comprising" shall be understood to mean "comprising at least one".

Brief Description of the Drawings

[0028]

Figure 1

Embodiments for Carrying Out the Invention

[0029] First, the present invention relates to the use of a composition comprising one or more diesters for cooling and / or lubricating a propulsion system of an electric or hybrid vehicle, each of said diesters being formed between a diol having 3 to 12 carbon atoms and two linear or branched monocarboxylic acids having 4 to 10 carbon atoms, which may be the same or different.

[0030] The present invention further relates to the use of one or more diesters for cooling and / or lubricating a propulsion system of an electric or hybrid vehicle, each of said diesters being formed between a diol having 3 to 12 carbon atoms and two linear or branched monocarboxylic acids having 4 to 10 carbon atoms, which may be the same or different.

[0031] The present invention can use one or more diesters, each of said diesters being - a diol selected from 1,2-propanediol, 1,2-decanediol, and 1,3-diols having 3 to 10 carbon atoms, and - having a linear or branched hydrocarbon chain having 5 to 10 carbon atoms and formed between two monocarboxylic acids which may be the same or different thereof.

[0032] More specifically, it is possible to prepare a mixture of diesters by reacting the diol with a mixture of monocarboxylic acids.

[0033] For example, it is possible to react the diol with three monocarboxylic acids A1, A2, and A3. Thus, according to such an example, the mixture of diesters falling within the scope of the present invention is - a diester formed between the diol and two acids A1, - a diester formed between the diol and two acids A2, - a diester formed between the diol and two acids A3, -Diesters formed between the diol and acids A1 and A2, -Diesters formed between the diol and acids A1 and A3, -Diesters formed between the diol and acids A2 and A3 may be included.

[0034] The diesters used according to the present invention As described above, the diester(s) used according to the present invention are formed between a diol and two monocarboxylic acids.

[0035] The "diester formed between a diol and two monocarboxylic acids" defined by the present invention refers to a compound obtained by two esterification reactions, and each esterification reaction is carried out between one of the two alcohol functional groups of the diol and one of the acid functional groups of the two monocarboxylic acids.

[0036] According to a preferred embodiment, the diester has 13 to 25 carbon atoms, preferably 15 to 24 carbon atoms.

[0037] The diol used in the present invention has 3 to 12 carbon atoms. Preferably, at least one of the two hydroxyl functional groups of the diol is held by a primary carbon atom.

[0038] A carbon atom is called primary when it is bonded to only one other carbon atom.

[0039] According to one embodiment, the diol is selected from 1,2-propanediol, 1,2-decanediol, and 1,3-diols having 3 to 12 carbon atoms.

[0040] The "diol" refers to a compound (precisely) containing two hydroxyl functional groups (-OH).

[0041] "1,3-diol containing X to Y carbon atoms" means a diol in which the alcohol functional groups are located at the 1-position and 3-position of a hydrocarbon chain containing X to Y carbon atoms, respectively.

[0042] Preferably, the 1,3-diol is selected from 1,3-diols having 3 to 10 carbon atoms, preferably 3 to 7 carbon atoms.

[0043] The "hydrocarbon chain" defined by the present invention refers to a linear or branched saturated or unsaturated alkyl chain or alkylene chain. The hydrocarbon chain may be interrupted by one or more heteroatoms, more specifically one or more oxygen atoms. Preferably, the hydrocarbon chain is a linear or branched saturated or unsaturated alkyl chain or alkylene chain consisting of carbon atoms and hydrogen atoms.

[0044] According to one embodiment, the 1,3-diol having 3 to 12 carbon atoms is selected from 1,3-alkanediols having 3 to 12 carbon atoms.

[0045] "1,3-alkanediol having X to Y carbon atoms" means a diol in which the alcohol functional groups are located at the 1-position and 3-position of an alkane chain having X to Y carbon atoms, respectively.

[0046] According to one embodiment, the diol is selected from 1,2-propanediol, 1,2-decanediol, and 1,3-diols having 3 to 7 carbon atoms, preferably 1,2-propanediol and 1,3-alkanediols having 3 to 7 carbon atoms, more preferably 1,2-propanediol and 1,3-propanediol. Advantageously, the diol is 1,2-propanediol.

[0047] The diol used according to the present invention may be commercially available or may be synthesized according to any method well known to those skilled in the art.

[0048] Preferably, the diol used according to the present invention contains a content of carbon of biological origin of at least 60% by weight, preferably at least 70% by weight, or preferably at least 80% by weight, or more preferably at least 90% by weight, based on the total weight of the carbon atoms of the diol.

[0049] Within the framework of the present invention, the content of carbon of biological origin can be measured according to the standard ASTM D6866.

[0050] The diester used according to the present invention is obtained from two monocarboxylic acids that are the same or different.

[0051] "Monocarboxylic acid" means a compound containing a single carboxyl functional group (-COOH).

[0052] The hydroxycarboxylic acid used to form the diester of the present invention is selected from monocarboxylic acids having a straight-chain hydrocarbon chain having 4 to 10 carbon atoms, preferably 5 to 9 carbon atoms, or preferably 5 to 8 carbon atoms. Preferably, the straight-chain or branched hydrocarbon chain of the monocarboxylic acid is saturated.

[0053] According to one embodiment, the plurality of monocarboxylic acids are the same or different and include a straight-chain hydrocarbon chain having 4 to 10 carbon atoms, preferably 5 to 9 carbon atoms, or preferably 5 to 8 carbon atoms.

[0054] According to one embodiment, the plurality of monocarboxylic acids are the same or different and include a straight-chain saturated hydrocarbon chain having 5 to 10 carbon atoms, preferably 5 to 9 carbon atoms, or preferably 5 to 8 carbon atoms.

[0055] The monocarboxylic acid used according to the present invention may be commercially available or may be synthesized according to any method known to those skilled in the art.

[0056] Preferably, the monocarboxylic acid used according to the present invention contains at least 60% by weight, preferably at least 70% by weight, or preferably at least 80% by weight, or more preferably at least 90% by weight of carbon of biological origin, based on the total weight of the carbon atoms of the diol.

[0057] Within the framework of the present invention, the carbon content of biological origin can be measured according to the standard ASTM D6866.

[0058] Preferably, the diester(s) used in the present invention is saturated.

[0059] The "saturated diester" defined by the present invention means a diester having a saturated hydrocarbon chain. Therefore, preferably, the diol used according to the present invention contains a saturated hydrocarbon chain, and each of the plurality of monocarboxylic acids used according to the present invention contains a saturated hydrocarbon chain. Preferably, the hydrocarbon chain consists of carbon atoms and hydrogen atoms.

[0060] According to a preferred embodiment, the diester used according to the present invention is a branched diester.

[0061] The "branched diester" defined by the present invention refers to a diester having a branched hydrocarbon chain that can be located between two ester functional groups and / or at one or both ends of the diester.

[0062] According to a preferred embodiment, the diester used in the present invention is saturated and branched.

[0063] According to one embodiment, the kinematic viscosity of the diester used according to the present invention, measured at 100 °C according to the standard ASTM D445, is in the range of 1 to 6 mm 2 / s, preferably 1 to 4 mm 2 / s.

[0064] According to one embodiment, the diester according to the present invention has a kinematic viscosity measured at 40 °C in accordance with standard ASTM D445 of 2 to 20 mm 2 / s, preferably 3 to 10 mm 2 / s.

[0065] It is understood that the definitions provided above for the carboxylic acid and the alcohol can be combined, to the extent possible, to define other specific embodiments.

[0066] The diester used according to the present invention may more specifically correspond to the following formula (I).

Chemical formula

[0067] Preferably, the diester(s) corresponding to formula (I) has 13 to 25 carbon atoms, preferably 15 to 24 carbon atoms.

[0068] According to certain embodiments, the group R 3 represents the following moiety: -CH(G 1 )-CH(G 2 ), and wherein G 1 and G 2 each independently represent a hydrogen atom or a linear or branched, preferably linear, saturated or unsaturated, preferably saturated hydrocarbon chain having from 1 to 8 carbon atoms, and it is understood that G 1 and G 2 cannot both be hydrogen.

[0069] Preferably, one of G 1 or G 2 is a hydrogen atom.

[0070] According to one embodiment, the diester(s) used according to the present invention is / are a diester formed from 1,2-decanediol and two heptanoic acids, a diester formed from 1,2-decanediol and two pentanoic acids, a diester formed from 1,2-propanediol and two heptanoic acids, a diester formed from 1,2-propanediol and two nonanoic acids, a diester formed from 1,3-propanediol and two heptanoic acids, a diester formed from 1,2-propanediol and two octanoic acids, a diester formed from 1,2-propanediol and two decanoic acids, a diester formed from 1,2-propanediol and octanoic acid and decanoic acid, and mixtures thereof.

[0071] The diesters according to the present invention can be prepared according to synthetic methods known to those skilled in the art. The synthetic method more specifically uses two esterification reactions, each esterification reaction being carried out between the alcohol functional group of the diol and the acid functional group of the monocarboxylic acid.

[0072] Of course, it is the role of those skilled in the art to adjust the synthesis conditions to obtain the diesters according to the present invention.

[0073] Within the framework of the present invention, it is understood that the diesters according to the present invention may be in the form of at least two diesters according to the present invention, more specifically a mixture of the diesters defined above.

[0074] Preferably, the diesters used according to the present invention contain a carbon content of at least 60% by weight, preferably at least 70% by weight, or preferably at least 80% by weight, or more preferably at least 90% by weight of carbon of biological origin, based on the total weight of the carbon atoms of the diester.

[0075] Within the framework of the present invention, the carbon content of biological origin can be measured according to the standard ASTM D6866.

[0076] The diester or mixture of diesters according to the present invention may correspond to at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, more preferably at least 50% by weight, or more preferably at least 70% by weight, more specifically at least 80% by weight, more specifically at least 90% by weight, or even at least 95% by weight of the composition used according to the present invention.

[0077] The diester(s) used according to the present invention can be used together with one or more auxiliary base oils (also called co-base). According to one embodiment, the composition comprises, based on the total weight of the diester(s) and a base oil different from the diester, - 5 to 95% by weight, preferably 5 to 50% by weight, more preferably 10 to 40% by weight of one diester or a plurality of diesters according to the present invention, and - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight of one or more different base oils according to the present invention comprises

[0078] According to one embodiment, the composition used in accordance with the present invention may comprise, based on the total weight of the composition, at least 30% by weight, more specifically between 50% by weight and 99.5% by weight, preferably between 70% by weight and 99% by weight, more preferably between 80% by weight and 99% by weight, or even between 80% by weight and 95% by weight, of a diester or mixture of diesters according to the present invention.

[0079] According to a particular embodiment, the cooling and / or lubricating composition according to the present invention may consist of more than 95% by weight, more specifically more than 98% by weight, of one or more diesters according to the present invention, or even 100% by weight of one or more diesters according to the present invention.

[0080] According to a particular embodiment, the cooling composition used in accordance with the present invention preferably has the composition such that, based on the total weight of the cooling composition, - 5 to 95% by weight, preferably 5 to 50% by weight, more preferably 10 to 40% by weight of said one diester or plurality of diesters according to the present invention, and - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight of one or more different base oils according to the present invention in proportions such that the mixture of the diester(s) and the auxiliary base oil(s) as defined in the present invention comprises 100% by weight.

[0081] Auxiliary base oil(s) The cooling and / or lubricating composition used in accordance with the present invention may comprise, in addition to one or more diesters according to the present invention, one or more base oils different from the diesters according to the present invention.

[0082] The one or more base oils, which are present where appropriate in the cooling and / or lubricating composition according to the present invention, are appropriately selected in terms of compatibility with the one or more diesters used in accordance with the present invention.

[0083] There can be mixtures of a plurality of base oils, for example, mixtures of two, three, or four base oils.

[0084] Preferably, the base oil or mixture of auxiliary base oils used in the cooling composition according to the present invention has a kinematic viscosity measured at 100 °C in accordance with Standard ASTM D445 of 1.5 to 8 mm 2 / s, particularly 1.5 to 6.1 mm 2 / s, more specifically 1.5 to 4.1 mm 2 / s, even more specifically 1.5 to 2.1 mm 2 / s.

[0085] The base oil is defined by the American Petroleum Institute (API) classification (or its equivalent according to the Association Technique de l’Industrie Europeenne des Lubrifiants (ATIEL) classification) and can be selected from mineral oils or synthetic oils belonging to Groups I to V according to the classes shown in Table 1 below.

Table 1

[0086] Examples of mineral base oils include any type of base oil obtained by purification operations such as atmospheric and vacuum distillation of crude oil, subsequent solvent extraction, dewaxing, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization, and hydrofinishing.

[0087] Mixtures of biosourced synthetic oils and mineral oils can also be used.

[0088] Regarding the use of various additional base oils for manufacturing cooling and / or lubricating compositions, there are generally no restrictions, except that the composition needs to have properties suitable for use in the propulsion system of either an electric or hybrid vehicle, particularly properties related to the viscosity index, sulfur content, or oxidation resistance.

[0089] The base oil can be further selected from synthetic oils such as specific carboxylic acid esters and alcohol esters other than the diesters defined by the present invention, from polyalphaolefins (PAO), and from polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides containing 2 to 8 carbon atoms, more specifically 2 to 4 carbon atoms.

[0090] The PAO used as the base oil is obtained, for example, from monomers containing 4 to 32 carbon atoms, such as octene or decene.

[0091] The weight average molecular weight of PAO can vary quite widely. Preferentially, the weight average molecular weight of PAO is less than 600 Da. The weight average molecular weight of PAO can further be in the range of 100 - 600 Da, 150 - 600 Da, or further 200 - 600 Da.

[0092] For example, the PAO used in the context of the present invention, having a kinematic viscosity measured at 100 °C according to standard ASTM D445 in the range of 1.5 - 8 mm 2 / s, is commercially available from Ineos under the trademarks Durasyn® 162, Durasyn® 164, Durasyn® 166, and Durasyn® 168.

[0093] Advantageously, one or more additional base oils are selected from polyalphaolefins (PAO).

[0094] It is the role of the person skilled in the art to adjust the content of the auxiliary base oil(s) present in the cooling and / or lubricating composition according to the present invention.

[0095] According to one embodiment, the composition according to the present invention may contain one or more base oils different from the diester according to the present invention in an amount of 5 to 95% by weight, preferably 50 to 95% by weight, or preferably 60 to 90% by weight based on the total weight of the composition.

[0096] Additive The cooling and / or lubricating composition according to the present invention may further contain one or more additives known to those skilled in the art in the field of lubrication and / or cooling of the electric propulsion system of a hybrid vehicle.

[0097] Additives that can be incorporated into the composition according to the present invention include antioxidants, pour point depressants, defoamers, corrosion inhibitors, antiwear agents and / or extreme pressure additives, friction modifiers, detergents, dispersants, and mixtures thereof. More specifically, they can be selected from antioxidants, pour point depressants, defoamers, and corrosion inhibitors.

[0098] Preferably, the cooling and / or lubricating composition according to the present invention may further contain one or more additives selected from antioxidants, defoamers, pour point improvers, and corrosion inhibitors.

[0099] By adding one or more additives selected from antiwear additives, friction modifiers, detergents, extreme pressure additives, and dispersants, the cooling composition according to the present invention can be used as a multifunctional fluid. For example, in a framework for cooling battery and / or power electronics components and lubricating parts of the propulsion system, such as the transmission of an electric or hybrid vehicle, it can also be proven to be advantageous.

[0100] It is understood that the nature and amount of the additives used are selected so as not to affect the properties of the cooling and / or lubricating composition imparted by the diester according to the present invention.

[0101] Such additives can be introduced as a mixture with, and / or individually as, additives already commercially available for commercial lubricant formulations for vehicle engines having performance levels defined by the European Automobile Manufacturers Association (ACEA) and / or the American Petroleum Institute (API), which are well known to those skilled in the art.

[0102] The additive(s) may be present in the cooling and / or lubricating composition according to the invention in a content in the range of 10% by weight or less, more specifically 5% by weight or less, more specifically 0.01 to 3% by weight, based on the total weight of the composition.

[0103] Thereby, the cooling and / or lubricating composition used according to the invention can comprise at least one antioxidant additive.

[0104] The present invention further relates, according to another aspect thereof, to a cooling and / or lubricating composition, more specifically to a propulsion system, more specifically to a cooling and / or lubricating composition suitable for cooling a motor or motor reduction gear, a battery and / or power electronics components of an electric or hybrid vehicle, said composition comprising (i) at least one diester as defined above, and (ii) at least one antioxidant additive.

[0105] The antioxidant additive can generally delay the decomposition of the composition during use. Such decomposition can result, inter alia, in the formation of deposits, the presence of sludge, or an increase in the viscosity of the composition.

[0106] The antioxidant additive acts, in particular, as a radical inhibitor or a hydroperoxide breaker. Commonly used antioxidant additives include phenolic antioxidants, amine antioxidant additives, and phosphorus-sulfur antioxidant additives. Among such antioxidant additives, there are those that can generate ash, such as phosphorus-sulfur antioxidant additives for example. The phenolic antioxidant additive can be ash-free or can be in the form of a neutral or basic metal salt. The antioxidant additive is, in particular, a sterically hindered phenol, an ester of a sterically hindered phenol, and a sterically hindered phenol containing a thioether bridge, diphenylamine, at least one C1-C 12 diphenylamine substituted with an alkyl moiety, N,N'-dialkylaryldiamine, and mixtures thereof can be selected.

[0107] Preferably, according to the present invention, the sterically hindered phenol is such that at least one of the carbons adjacent to the carbon atom having an alcohol functional group is substituted by at least one C1-C 10 alkyl moiety, preferably a C1-C6 alkyl moiety, preferably a C4 alkyl moiety, preferably a tert-butyl moiety, and is selected from compounds containing a phenol moiety.

[0108] The amine compound is another class of antioxidant additive that can be used, optionally in combination with a phenolic antioxidant additive. Examples of amine compounds include aromatic amines, for example, the formula NR 4 R 5 R 6 (wherein R 4 represents an aliphatic moiety or an optionally substituted aromatic moiety, R 5 represents an optionally substituted aromatic moiety, R 6 represents a hydrogen atom, an alkyl moiety, an aryl moiety, or a moiety having the formula R 7 S(O) z R 8 wherein R 7 represents an alkylene or alkenylene moiety, R 8represents an alkyl moiety, an alkenyl moiety or an aryl moiety, and z is 0, 1 or 2), which is an aromatic amine.

[0109] Alkyl sulfur phenol, or its alkali metal salt or alkaline earth metal salt may be further used as an antioxidant additive.

[0110] Another class of antioxidant additives is the class of copper compounds, for example, copper thiophosphate or copper dithiophosphate, copper salts and carboxylates, copper dithiocarbamate, copper sulfonate, copper phenate, copper acetylacetonate. Copper salts I and II, succinates or succinic anhydrides may also be used.

[0111] Advantageously, the cooling and / or lubricating composition contains at least one ashless antioxidant additive.

[0112] The additive(s) may be used in a proportion of 0.1 to 2% by weight based on the total weight of the composition in the cooling composition according to the present invention.

[0113] The cooling and / or lubricating composition according to the present invention may further contain at least one antiwear and / or extreme pressure additive.

[0114] Antiwear additives and extreme pressure additives protect the surface subject to friction by forming a protective film adsorbed on the surface.

[0115] There are a wide variety of antiwear additives. Preferably, the antiwear additive is selected from phosphorus-sulfur additives such as metal alkyl thiophosphates, more specifically zinc alkyl thiophosphates, especially zinc dialkyldithiophosphate (ZnDTP). Preferred compounds have the formula Zn((SP(S)(OQ 2 )(OQ 3 ))2, wherein Q 2 and Q 3are the same or different and independently represent an alkyl moiety, preferably an alkyl moiety containing from 1 to 18 carbon atoms.

[0116] Aminophosphates are also antiwear additives that can be used in the lubricating compositions according to the invention. However, the phosphorus provided by such additives can form ash and thus may act as a poison in automotive catalyst systems. Such effects can be minimized by partially replacing the aminophosphates with additives that do not provide phosphorus, such as polysulfides, especially sulfur olefins.

[0117] The cooling and / or lubricating composition may contain from 0.01 to 6% by weight, preferably from 0.05 to 4% by weight, or more preferably from 0.1 to 2% by weight, of antiwear and extreme pressure additives, based on the total weight of the composition.

[0118] The cooling and / or lubricating composition according to the invention may further contain an antifoaming agent.

[0119] The antifoaming agent can be selected from silicones.

[0120] The cooling and / or lubricating composition may contain from 0.01 to 2% by weight or from 0.01 to 5% by weight, preferably from 0.1 to 1.5% by weight or from 0.1 to 2% by weight, of antifoaming agent, based on the total weight of the composition.

[0121] The cooling and / or lubricating composition according to the invention may further contain at least one friction modifier additive.

[0122] The friction modifier additive can be selected from compounds providing metal elements and ashless compounds. Examples of compounds providing metal elements include complexes of transition metals such as Mo, Sb, Sn, Fe, Cu, Zn, etc., and the ligands thereof can be hydrocarbon compounds containing oxygen atoms, nitrogen atoms, sulfur atoms or phosphorus atoms. The ashless friction modifier additive is generally of organic origin and can be selected from fatty acids and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, fatty amino acids or fatty acid glycerol esters. According to the present invention, the fatty compound contains at least one hydrocarbon moiety containing 10 to 24 carbon atoms.

[0123] The cooling and / or lubricating composition may contain 0.01 to 2 wt% or 0.01 to 5 wt%, preferably 0.1 to 1.5 wt% or 0.1 to 2 wt% of the friction modifier additive based on the total weight of the composition.

[0124] Advantageously, the cooling and / or lubricating composition does not contain any friction modifier additive, more specifically for use aimed at cooling the battery part.

[0125] The cooling and / or lubricating composition according to the present invention can contain at least one detergent additive.

[0126] The detergent additive generally reduces the formation of deposits on the surface of the metal part by dissolving the by-products of oxidation and combustion.

[0127] The detergent additives that can be used in the cooling and / or lubricating composition are generally known to those skilled in the art. The detergent additive can be an anionic compound containing a lipophilic hydrocarbon moiety and a hydrophilic head. The associated cation can be a metal cation of an alkali metal or an alkaline earth metal.

[0128] The cleaning additive is preferably selected from alkali metal salts or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, and phenate salts. The alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium, or barium.

[0129] Such metal salts generally contain the metal in stoichiometric amounts or in excess, i.e., at a concentration higher than the stoichiometric amount. As a result, these metal salts become overbased detergents, and the excess metal that imparts overbased characteristics to the cleaning additive is generally in the form of oil-insoluble metal salts, such as carbonates, hydroxides, oxalates, acetates, glutamates, preferably carbonates.

[0130] The cooling and / or lubricating composition can contain, for example, 2 to 4% by weight of the cleaning additive, based on the total weight of the composition.

[0131] The cooling and / or lubricating composition may also contain at least one pour point depressant additive.

[0132] Pour point depressant additives generally improve the behavior of the composition under low-temperature conditions by retarding the formation of paraffin crystals. Examples of pour point depressant additives include alkyl polymethacrylates, polyacrylates, polyaryl amides, polyalkyl phenols, polyalkyl naphthalenes, and alkylated polystyrenes.

[0133] Also, the cooling and / or lubricating composition may contain at least one dispersant.

[0134] The dispersant can be selected from Mannich bases, succinimides, and their derivatives. The cooling composition can contain, for example, 0.2 to 10% by weight of the dispersant, based on the total weight of the composition.

[0135] According to certain embodiments, the cooling and / or lubricating compositions used in accordance with the present invention comprise (i) at least one diester according to the present invention, and (ii) an antioxidant, an antifoaming agent, a pour point depressant, a corrosion inhibitor, an antiwear and / or extreme pressure additive, a friction modifier, a detergent, a dispersant, and mixtures thereof, preferably at least one additive selected from an antioxidant, a pour point depressant, an antifoaming agent, and a corrosion inhibitor, or further consists of (i) and (ii).

[0136] Advantageously, the cooling and / or lubricating compositions used in accordance with the present invention consist of (i) at least one diester corresponding to one of the formulas (I) defined above, and (ii) at least one antioxidant additive.

[0137] According to certain embodiments, the cooling and / or lubricating compositions used in accordance with the present invention - at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, preferably at least 50% by weight, more preferably at least 70% by weight, or even at least 90% by weight of the diester(s) corresponding to formula (I), - optionally, 0.01 to 20% by weight, preferably 0.05 to 15% by weight, more preferably 0.1 to 10% by weight, or more preferably 0.5 to 7% by weight, or even 1 to 5% by weight of one or more additives selected from friction modifier additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoaming agents, thickeners, corrosion inhibitors, copper thickeners, and mixtures thereof, - optionally, 5 to 94% by weight, preferably 10 to 94% by weight, preferably 15 to 90% by weight of one or more base oils different from the diesters according to the present invention and contain or further consist of them, The above contents are expressed based on the total weight of the composition.

[0138] According to certain embodiments, the cooling and / or lubricating composition used in accordance with the present invention comprises - 5 to 95% by weight, preferably 5 to 50% by weight, or preferably 10 to 40% by weight of said diester(s) corresponding to formula (I), and - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight of one or more different said diesters, and - Optionally, 0.01 to 20% by weight, preferably 0.05 to 15% by weight, more preferably 0.1 to 10% by weight, or more preferably 0.5 to 7% by weight, or even 1 to 5% by weight of one or more additives selected from friction modifier additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoaming agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof, and comprises or further consists of these, wherein the above contents are expressed based on the total weight of the composition.

[0139] According to certain embodiments, the cooling and / or lubricating composition used in accordance with the present invention comprises - 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 20 to 80% by weight, even more preferably 30 to 70% by weight, or even 40 to 60% by weight of diester(s) corresponding to formula (I), and - Optionally, 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 20 to 80% by weight, or even more preferably 30 to 70% by weight, or even 40 to 60% by weight of one or more base oils different from said diesters, and - Optionally, one or more additives that are separate from the diester and separate from the base oil(s), in an amount of 0.01 to 20% by weight, preferably 0.05 to 15% by weight, more preferably 0.1 to 10% by weight, or more preferably 0.5 to 7% by weight, or even more preferably 1 to 5% by weight, selected from one or more of friction modifiers, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, antifoaming agents, thickeners, corrosion inhibitors, copper passivators, and mixtures thereof comprising or further consisting of The above content is expressed based on the total weight of the composition.

[0140] The cooling and / or lubricating composition used according to the present invention advantageously has a kinematic viscosity measured at 100 °C according to standard ASTM D445 in the range of 1 to 6 mm 2 / s, preferably 1 to 4 mm 2 / s.

[0141] The cooling and / or lubricating composition used according to the present invention advantageously has a kinematic viscosity measured at 40 °C according to standard ASTM D445 in the range of 2 to 20 mm 2 / s, preferably 3 to 10 mm 2 / s.

[0142] Use As shown above, the composition according to the present invention can be used as a cooling and / or lubricating fluid for the propulsion system of an electric or hybrid vehicle.

[0143] As schematically shown in FIG. 1, the propulsion system of an electric or hybrid vehicle comprises in particular an electric motor (1) part, an electric battery (2), a transmission, and more specifically a reduction gear (3).

[0144] An electric motor typically comprises power electronics components (11) connected to a stator (13) and a rotor (14). The stator comprises coils, more specifically copper coils, to which current is supplied alternately, thereby generating a rotating magnetic field. The rotor itself comprises coils or permanent magnets or other magnetic materials and rotates by the rotating magnetic field.

[0145] The power electronics components (11), stator (13) and rotor (14) of the propulsion system (1) are parts with complex structures and parts that generate a large amount of heat during motor operation. Therefore, it is essential to cool the electric motor and the power electronics components.

[0146] The bearing (12) is generally integrated between the stator (13) and the rotor (14). A transmission, more specifically a reduction gear (3), functions to reduce the rotational speed according to the output of the electric motor and adapt the speed transmitted to the wheels, and at the same time enables control of the vehicle speed.

[0147] Advantageously, the composition according to the present invention can be used to cool the battery of an electric or hybrid vehicle. More specifically, according to such an embodiment, the composition is intended to be in direct contact with the battery.

[0148] Suitable batteries for the propulsion system of an electric or hybrid vehicle include, in particular, lithium-ion batteries or nickel-cadmium batteries.

[0149] According to another aspect of the present invention, there is provided a method for cooling at least a part of the propulsion system of an electric or hybrid vehicle, more specifically a battery, the method comprising at least one step of bringing at least said part, in particular said battery, for example a lithium-ion battery or a nickel-cadmium battery, into contact with a composition comprising at least one diester according to the present invention as defined above.

[0150] Contact of the cooling composition according to the present invention with the battery may consist of immersion or semi-immersion of the battery in said composition, or spraying of said composition onto the surface of the battery.

[0151] 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 part of the battery is in contact with said composition.

[0152] Cooling may be carried out by any method known to those skilled in the art. The battery may be immersed or semi-immersed in said composition and may be stationary or in circular motion.

[0153] Examples of direct contact include cooling by injection, ejection, spraying, immersion or semi-immersion in a bath, or cooling by forming a mist on the battery from the composition according to the present invention under pressure and gravity.

[0154] Advantageously, said composition is injected into the compartments of the propulsion system to be cooled by being ejected under a fairly high pressure. Advantageously, the shear generated by the injection reduces the viscosity of the fluid in the injection compartment compared to the kinematic viscosity at rest, thereby making it possible to further enhance the cooling capacity of said composition.

[0155] Also, an oil circulation system commonly used in electric motors can be used, as described, for example, in the document WO 2015 / 116496.

[0156] The composition according to the present invention may also be used to cool the electric motor of an electric or hybrid vehicle, more specifically, to cool the power electronics and / or the rotor and / or the stator of the electric motor, and / or the motor reduction gear.

[0157] The cooling composition according to the present invention has particularly satisfactory electrical insulation properties for use in electric or hybrid vehicles.

[0158] In addition to the cooling characteristics of the composition according to the present invention, it is possible to utilize its lubricating characteristics.

[0159] Thereby, the composition according to the present invention can be used simultaneously to lubricate various parts of the propulsion system of an electric or hybrid vehicle, more specifically, the bearings disposed between the rotor and the stator of an electric motor, or the transmission in an electric or hybrid vehicle, more specifically, the reduction gears.

[0160] In such applications, the cooling composition according to the present invention preferably also contains one or more additives selected from anti-wear additives, friction modifiers, detergents, dispersants, extreme pressure additives, and mixtures thereof.

[0161] Next, the present invention will be described by the following examples, which are, of course, given as illustrations of the present invention and are not limited thereto.

Example

[0162] Example Example 1: Preparation of the compound to be tested The following compounds were prepared. - Diester A: A diester formed from 1,2 - decanediol and two heptanoic acids - Diester B: A diester formed from 1,2 - decanediol and two pentanoic acids - Diester C: A diester formed from 1,2 - propanediol and two heptanoic acids - Diester D: A diester formed from 1,2 - propanediol and two nonanoic acids - Diester E: A diester formed from 1,3 - propanediol and two heptanoic acids - Diester F: A mixture of diesters formed from 1,2 - propanediol and a fraction of C8 - C10 acids of biological origin A monoester formed from a monocarboxylic acid having a saturated hydrocarbon chain of 3 to 14 carbon atoms and a monoalcohol having a saturated hydrocarbon chain of 3 to 14 carbon atoms.

[0163] The diesters and monoesters were prepared according to known ester preparation methods.

[0164] Example 2: Viscosity measurement The kinematic viscosity at 100 °C (KV100) and the kinematic viscosity at 40 °C (KV40) of the compound of Example 1 were determined according to the standard ASTM D445.

[0165] The viscosities are shown in Table 2.

Table 2

[0166] All diesters used according to the present invention have a viscosity of less than 4 mm 2 / s at 100 °C.

[0167] Example 3: Measurement of thermal conductivity The thermal conductivity of the compound described in Example 1 was determined at various temperatures according to the standard ASTM D7896-19.

[0168] The results are shown in Table 3.

Table 3

[0169] From the results, it is shown that the diesters used according to the present invention have good thermal properties, and thus the use of the diesters as a cooling fluid in the propulsion system of electric or hybrid vehicles is possible.

[0170] Example 4: Mini flash point measurement The flash point is measured according to the standard ASTM D93Ac (Cleveland open cup method).

[0171] Those values are shown in Table 4.

Table 4

[0172] As shown by the values in Table 4, the flash point is better when the diester is a branched diester. In fact, the diesters formed from 1,2-propanediol have a lower flash point than the diesters formed from 1,3-propanediol, which all have the same number of carbon atoms.

Claims

1. Use of a composition comprising one or more diesters for cooling and / or lubricating a propulsion system of an electric or hybrid vehicle, wherein each of said diesters is formed between a diol containing 3 to 12 carbon atoms and two linear or branched monocarboxylic acids having 4 to 10 carbon atoms, which may be the same or different, and said hydrocarbon chain is optionally interrupted by one or more heteroatoms, use of a composition comprising one or more diesters.

2. Use according to claim 1, wherein said linear or branched hydrocarbon chain having 4 to 10 carbon atoms is a linear or branched saturated or unsaturated alkyl or alkylene chain consisting of carbon atoms and hydrogen atoms.

3. Use according to claim 1 or 2, wherein said composition comprises at least 5% by weight, preferably at least 10% by weight, or preferably at least 30% by weight, more preferably at least 50% by weight, or even at least 70% by weight, or 100% by weight of said diester(s).

4. Use according to claim 1 or 2, wherein said composition comprises, based on the total weight of said diester(s) and a base oil different from said diester, - 5 to 95% by weight, preferably 5 to 50% by weight, or preferably 10 to 40% by weight of said one or more diesters, and - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight of one or more base oils different from said diester.

5. Use according to any one of claims 1 to 4 for cooling a battery and / or power electronics components of an electric or hybrid vehicle, more specifically a lithium-ion battery or a nickel-cadmium battery.

6. Use according to any one of claims 1 to 5, wherein said diester has 13 to 25 carbon atoms, preferably 15 to 24 carbon atoms.

7. Said one or more diesters are of the following formula (I): (wherein, 【Chemical 1】 Use according to any one of claims 1 to 6. -R １ represents a linear or branched, saturated or unsaturated, preferably saturated hydrocarbon chain having 3 to 9 carbon atoms, preferably 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms, and the hydrocarbon chain is optionally interrupted by one or more heteroatoms such as oxygen atoms, and preferably, the hydrocarbon chain consists of carbon atoms and hydrogen atoms, -R ２ represents a linear or branched saturated or unsaturated, preferably saturated hydrocarbon chain having 4 to 9 carbon atoms, and the hydrocarbon chain is optionally interrupted by one or more heteroatoms such as oxygen atoms, and preferably, the hydrocarbon chain consists of carbon atoms and hydrogen atoms, -R ３ represents a linear or branched saturated or unsaturated hydrocarbon chain having 3 to 10 carbon atoms, preferably a saturated hydrocarbon chain, and the hydrocarbon chain is optionally interrupted by one or more heteroatoms such as oxygen atoms, and preferably, the hydrocarbon chain consists of carbon and hydrogen atoms.), corresponding to

8.

9. the diester has a kinematic viscosity in the range of 1 to 6 mm ２ / s at 100°C, preferably in the range of 1 to 4 mm ２ / s at 100°C, the use according to any one of claims 1 to 7. Use according to any one of claims 1 to 8, wherein at least one of the two hydroxyl functional groups of said diol is supported by a primary carbon atom.

10. ​ Use according to any one of claims 1 to 9, wherein the diol is selected from 1,2-propanediol, 1,2-decanediol, and 1,3-alkanediols containing 3 to 10 carbon atoms.

11. Use according to any one of claims 1 to 10, wherein the diol is selected from 1,2-propanediol and 1,3-propanediol, and preferably, the diol is 1,2-propanediol.

12. Use according to any one of claims 1 to 11, wherein the plurality of monocarboxylic acids are the same or different and contain a linear hydrocarbon chain having 4 to 10 carbon atoms, preferably 5 to 9 carbon atoms.

13. The diester(s) is / are - one or more diesters formed between a diol selected from 1,2-decanediol and 1,3-propanediol and two monocarboxylic acids that are the same or different and contain a linear or branched hydrocarbon chain having 4 to 10 carbon atoms, - a diester formed from 1,2-propanediol and two heptanoic acids, - a diester formed from 1,2-propanediol and two octanoic acids, - a diester formed from 1,2-propanediol and two decanoic acids, - a diester formed from 1,2-propanediol and octanoic acid and decanoic acid, and mixtures thereof Use according to any one of claims 1 to 12, selected from

14. The one or more diesters are a diester formed from 1,2-decanediol and two heptanoic acids, a diester formed from 1,2-decanediol and two pentanoic acids, a diester formed from 1,2-propanediol and two heptanoic acids, a diester formed from 1,2-propanediol and two nonanoic acids, a diester formed from 1,3-propanediol and two heptanoic acids, a diester formed from 1,2-propanediol and two octanoic acids, a diester formed from 1,2-propanediol and two decanoic acids, a diester formed from 1,2-propanediol and octanoic acid and decanoic acid, Use according to any one of claims 1 to 13, selected from and mixtures thereof.

15. The use according to any one of claims 1 to 14, characterized in that the composition comprises, in addition to the diester(s), at least one additive selected from antioxidants, pour point depressants, defoamers, corrosion inhibitors, antiwear agents and / or extreme pressure additives, friction modifiers, detergents, dispersants and mixtures thereof, more specifically antioxidants, pour point depressants, defoamers and corrosion inhibitors.

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