KR102582462B1 - Lubricating oil composition for electric vehicle - Google Patents

Abstract

One embodiment of the present invention includes base oil and nanoparticles dispersed in the base oil, wherein the nanoparticles include a core and a shell surrounding the core, and the shell is composed of an unsaturated fatty acid and an amine-based compound. A lubricating oil composition for electric vehicles containing at least one or more of the following is provided, through which a lubricating oil composition for electric vehicles having high thermal conductivity and wear resistance can be provided.

Description

Lubricating oil composition for electric vehicles {LUBRICATING OIL COMPOSITION FOR ELECTRIC VEHICLE}

The present invention relates to a lubricant composition for electric vehicles.

Recently, the electric vehicle market has been growing rapidly in accordance with eco-friendly policies in countries around the world, and these electric vehicles sometimes require the use of products different from those that use conventional internal combustion engines.

Lubricants for electric vehicles have different characteristics from those used in conventional internal combustion engine vehicles, and lubricants for electric vehicles are focused on cooling and improving secondary battery efficiency. Due to the structural characteristics of electric vehicles, lubricants for electric vehicles may come into contact with electrical components and are thus affected by currents and electric fields. In this way, a lubricant composition for electric vehicles is needed to improve cooling and the efficiency of secondary batteries and increase driving range.

The technical problem to be achieved by the present invention is to provide a lubricant for electric vehicles with high thermal conductivity characteristics and a method for manufacturing the same.

In addition, the technical problem to be achieved by the present invention is to provide a lubricant for electric vehicles with improved lifespan due to high wear resistance and heat transfer, and a method for manufacturing the same.

In addition, the technical problem to be achieved by the present invention is to control the heat generated in the motor and reducer of the electric vehicle, thereby improving the lifespan of the lubricant for the electric vehicle and the parts of the electric vehicle, and the production of lubricating oil for the electric vehicle and the same that improves efficiency. It provides a method.

In addition, the technical problem to be achieved by the present invention is to provide a lubricant composition and a method for producing the same that can be universally used in electric vehicles including various types of electric motors and reducers.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention includes base oil and nanoparticles dispersed in the base oil, wherein the nanoparticles include a core and a shell surrounding the core, and the shell Provides a lubricant composition for electric vehicles containing unsaturated fatty acids.

Additionally, in one embodiment of the present invention, the core may be a lubricant composition for electric vehicles containing nanocarbon particles.

Additionally, in one embodiment of the present invention, the shell may be a lubricating oil composition for an electric vehicle that further includes an amine-based compound.

In addition, in one embodiment of the present invention, the shell may further include a ceramic layer surrounding the core, and the ceramic layer may be a lubricating oil composition for an electric vehicle whose surface is treated with the unsaturated fatty acid.

Additionally, in one embodiment of the present invention, the ceramic layer may be a lubricating oil composition for an electric vehicle further containing an amine-based compound.

Additionally, in one embodiment of the present invention, the ceramic layer may be a lubricating oil composition for an electric vehicle including a plurality of ceramic particles.

Additionally, in one embodiment of the present invention, the base oil may be a lubricating oil composition for an electric vehicle in which the nanoparticles are uniformly dispersed within the motor and the reducer.

Additionally, in one embodiment of the present invention, the nanoparticles may be a lubricating oil composition for electric vehicles having an average particle diameter of 100 to 200 nm.

Additionally, in one embodiment of the present invention, the nanoparticles may be a lubricating oil composition for an electric vehicle mixed in an amount of 0.1 wt% or less of the weight of the base oil inside the motor and reducer.

In addition, in one embodiment of the present invention, the lubricating oil composition for electric vehicles may further include at least one of an antioxidant, a cleaning dispersant, a viscosity index improver, an oiliness improver, and an anti-foaming agent. there is.

According to one embodiment of the present invention, a lubricant for electric vehicles having high thermal conductivity characteristics and a method for manufacturing the same can be provided.

In addition, according to an embodiment of the present invention, a lubricant for electric vehicles with improved lifespan due to high wear resistance and a method for manufacturing the same can be provided.

In addition, according to one embodiment of the present invention, it is possible to provide a lubricant composition that can be universally used in electric vehicles including various types of electric motors and reducers, and a method for manufacturing the same.

In addition, according to an embodiment of the present invention, by providing a lubricating oil composition for electric vehicles with high thermal conductivity characteristics, the effect of cooling the motor of an electric vehicle can be increased, and at the same time, the effect of cooling the motor of an electric vehicle can be increased due to its high wear resistance properties. It can provide the effect of reducing wear.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 is a diagram showing a schematic diagram of an electric vehicle.
Figure 2 is an exemplary diagram of nanoparticles included in a lubricant composition for electric vehicles provided by an embodiment of the present invention.
Figure 3 is an exemplary diagram of nanoparticles included in a lubricant composition for electric vehicles provided by an embodiment of the present invention.
Figure 4 is a conceptual diagram to explain the tendency of nanofluids to improve thermal conductivity.
Figure 5 is a cross-sectional view schematically showing the dispersion state of an additive containing conventional nanodiamonds and an additive according to an embodiment of the present invention.
Figure 6 is a diagram showing the results of a thermal conductivity test of a lubricating oil composition according to one embodiment.
Figures 7 and 8 are diagrams showing the results of a long-term dispersion stability test of a lubricating oil composition according to an embodiment.
Figure 9 is a flow chart showing a method for manufacturing a lubricant composition for an electric vehicle provided by an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

In this specification, “electric vehicle” refers to a vehicle that runs on electricity as a power source, meaning a vehicle that obtains kinetic energy using an electric motor, and excludes vehicles driven by an internal combustion engine. This concept includes all vehicles that obtain kinetic energy using electric motors, such as hydrogen vehicles and hybrid vehicles that use both an internal combustion engine and an electric motor.

Figure 1 is a diagram showing a schematic diagram of an electric vehicle. Referring to Figure 1, electric vehicles are often different in structure from conventional internal combustion engine vehicles. While conventional internal combustion engine vehicles control the power and speed of the vehicle by the engine and transmission, electric vehicles (V) have an electric motor (1) and a reducer (2) built in to control the rotation speed of the electric motor instead of the transmission. .

Accordingly, lubricants for electric vehicles generally perform different functions than lubricants for internal combustion engine vehicles, and one of their main purposes is to reduce energy loss and wear. In other words, lubricants for electric vehicles require different performance compared to lubricants for existing internal combustion engine vehicles.

As an example of the functions of lubricants for electric vehicles, lubricants for electric vehicles can quickly cool electric vehicle parts such as electric motors and gears and block unnecessary power flowing inside the vehicle. Through this, the lifespan of each part of the electric vehicle's electric motor can be extended, and the mechanical efficiency of the electric motor can be improved to extend the driving distance of the electric car. To achieve the above purpose, the performance of lubricants for electric vehicles can be improved by using additives.

To this end, the lubricating oil composition for electric vehicles according to the present invention provides a lubricating oil composition for electric vehicles containing nanoparticles formed in nanoscale.

One embodiment of the present invention includes base oil and nanoparticles 10 dispersed in the base oil, wherein the nanoparticles 10 include a core 100 and a shell surrounding the core 100 ( 200), wherein the shell 200 includes at least one of an unsaturated fatty acid and an amine-based compound, providing a lubricating oil composition for an electric vehicle.

Base oil is the oil that makes up lubricating oil, and although it varies from product to product, it accounts for a large portion of finished products.

In one embodiment, the base oil may include one or more of synthetic oil and natural oil having an appropriate lubricating viscosity, but it is not limited to the above example, and all base oils that can be used in the lubricating oil composition for electric vehicles are It should be interpreted as falling within the scope of rights of the present invention.

Additionally, in one embodiment, the base oil may contain two or more types of synthetic oil or two or more types of natural oil.

Figure 2 is an exemplary diagram of nanoparticles included in a lubricant composition for electric vehicles provided by an embodiment of the present invention.

Referring to Figure 2, the lubricating oil composition for an electric vehicle provided by an embodiment of the present invention includes nanoparticles 10 dispersed in base oil, wherein the nanoparticles 10 are connected to the core 100 and the It includes a shell 200 surrounding the core 100, and the shell 200 contains unsaturated fatty acids.

In one embodiment, the nanoparticles 10 include a surface-treated shell 200, so that the surface-treated shell 200 generates a repulsive force between the nanoparticles 10 to uniformly disperse them in the base oil. can be dispersed.

In one embodiment, the core 100 may include nanocarbon particles, and the nanocarbon particles may include nanodiamonds.

In one embodiment, nanodiamonds may have an average particle diameter (D ₅₀ ) of 30 to 40 nm.

If the average particle diameter (D ₅₀ ) of nanodiamonds exceeds 40 nm, the size of the particles becomes too large, causing a problem of low thermal conductivity, and if it is less than 30 nm, the size of the particles becomes too small, causing nanodiamonds to become too small. Since there is a problem that the effect due to the addition becomes insignificant, it is preferable that the average particle diameter (D ₅₀ ) of the nanodiamonds is set to the above 30 to 40 nm.

Diamond is a material that can be used in various industrial fields due to its advantages such as high hardness, chemical stability (corrosion resistance, acid resistance, base resistance), high thermal conductivity, and low thermal expansion. In addition, nanodiamonds repair worn areas on the metal surface. It has a restorative treatment effect and can provide additional effects such as extending the life of the machine.

In one embodiment, the core 100 may include a nucleophilic substituent on its surface, and the nucleophilic substituent includes, for example, a carboxyl group (-COOH), a hydroxyl group (-OH), and an amino group (- NH ₂ ), etc.

If a nucleophilic substituent is included on the surface, the nucleophilic substituent can form a chemical bond with one or more of the fatty acids and amine-based compounds included in the shell 200. Through this, the shell 200 surrounding the core 100 can be formed.

In one embodiment, unsaturated fatty acid refers to a fatty acid that has one carboxyl group in the R-COOH form and at least one double bond in the aliphatic chain. For example, the unsaturated fatty acid may be a C ₁₀ to C ₂₅ unsaturated fatty acid, and as another example, it may be a C ₁₅ to C ₂₂ unsaturated fatty acid.

In one embodiment, the unsaturated fatty acid may be one or more selected from the group consisting of omega-3 fatty acids, omega-6 fatty acids, omega-7 fatty acids, and omega-9 fatty acids.

In one embodiment, the unsaturated fatty acid is, for example, α-linolenic acid (ALA), stearidonic acid (SDA), eicosatrienoic acid (ETE), eicosatetraenoic acid (ETA), and eicosapentaene. Acid (EPA), heneicosapentaenoic acid (HPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), linoleic acid (LA), γ-linolenic acid (GLA), calendic acid acid, eicosadienoic acid, dihomo-γ-linolenic acid (DGLA), arachidonic acid, docosadienoic acid, adrenic acid, osbond acid acid), tetracosatetraenoic acid, palmitoleic acid, vaccenic acid, rumenic acid, paullinic acid, oleic acid, L It may be one or more selected from the group consisting of elaidic acid, gondoic acid, and mead acid, but is not limited to the above example, and is a long aliphatic acid having at least one double bond. Any fatty acid containing a chain should be interpreted as falling within the scope of the present invention.

In one embodiment, the core 100 and the unsaturated fatty acid may be mixed at 1:0.01 to 1:1 wt%, but are not limited thereto. In addition, the appropriate ratio of the core 100, which has the best dispersibility, and unsaturated fatty acids may differ depending on the type of core 100 and oil.

In one embodiment, the shell 200 may further include an amine-based compound. By further including an amine-based compound, dispersion stability in base oil can be improved.

In one embodiment, the amine-based compound may include one or more of a C ₅ to C ₂₀ primary aliphatic amine and a C ₂ to C ₆ aliphatic diamine.

In one embodiment, the amine-based compound is, for example, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine and dodecylamine, methylene Diamine (methylenediamine), ethylenediamine (ethylenediamine), propane-1,3-diamine, butane-1,4-diamine (butane-1,4-diamine), pentane- It may contain one or more selected from the group consisting of pentane-1,5-diamine and hexane-1,6-diamin, but the above It is not limited to this example, and all primary aliphatic amines of C ₅ to C ₂₀ and aliphatic diamines of C ₂ to C ₆ should be construed as falling within the scope of the present invention.

In one embodiment, the core 100 and the amine-based compound may be mixed at 1:0.01 to 1:1 wt%, but are not limited thereto.

Figure 3 is an exemplary diagram of nanoparticles included in a lubricant composition for electric vehicles provided by an embodiment of the present invention.

Referring to Figure 3, in one embodiment of the present invention, the shell 200 further includes a ceramic layer 300 surrounding the core 100, and the ceramic layer 300 may include an unsaturated fatty acid. By further including the ceramic layer 300, the thermal conductivity of the lubricating oil composition can be further improved.

In one embodiment, the ceramic layer 300 may include a plurality of ceramic particles 310, and the average particle diameter (D ₅₀ ) of the ceramic particles 310 may be 1 to 40 nm. In this way, by including the ceramic particles 310, the shell 200 can be stably formed and the thermal conductivity of the lubricating oil composition can be further improved.

At this time, the ceramic layer 300 refers to a layer containing a silicon compound or a silicon oxide compound. In one embodiment, the ceramic layer 300 may contain SiO ₂ .

When the average particle diameter (D ₅₀ ) of the ceramic particles 310 exceeds 40 nm, the thickness of the shell layer including the ceramic particles 310 becomes too large, causing a problem of lowering the thermal conductivity of the lubricating oil composition, and the average particle diameter (D ₅₀ ) is 1. When the thickness is less than nm, the thickness of the shell layer becomes thin and the effect of forming the shell layer becomes insignificant. Therefore, it is preferable that the average particle diameter (D ₅₀ ) of the ceramic particles 310 is 1 to 40 nm.

In one embodiment, the ceramic layer 300 may further include an amine-based compound on the surface.

In one embodiment, the ceramic layer 300 may be provided with one or more functional groups selected from the group consisting of carboxyl group, hydroxyl group, and amino group on the surface.

In one embodiment, the ceramic layer 300 may be 10 to 30 wt% relative to the total weight of the nanoparticles 10, in one example it may be 10 wt% to 25 wt%, and in another example It may be 20 wt% to 25 wt%, and in another example it may be 25 wt%.

If it exceeds 30 wt%, the ceramic layer becomes excessively large and the gap between the core and shell layer widens, which may cause problems in thermal conductivity and wear resistance. If it is less than 10 wt%, the ceramic layer is insufficient and the ceramic layer The effect of addition may be reduced.

In one embodiment, the nanoparticles 10 are disposed on the surface of the core 100 and may further include an intermediary material that can connect the core 100 and the ceramic layer 300.

In one embodiment, the intermediate material is an aliphatic compound having functional groups at both ends, and any aliphatic compound can be used as long as the functional group can be bonded to any one of a carboxyl group, a hydroxyl group, and an amino group, for example, It may be an aliphatic diamine, and as another example, the intermediary material may be an aliphatic diamine of C ₂ to C ₆ .

In one embodiment, the amino group disposed on one end of the intermediate material is chemically bonded with the functional group disposed on the surface of the core 100, and the amino group disposed on the other end of the intermediate material is chemically bonded with the functional group on the surface of the ceramic layer 300. can be combined

In one embodiment, at least one of the functional group disposed on the surface of the core 100 and the functional group disposed on the surface of the ceramic layer 300 may include a carboxyl group.

In one embodiment, at least one of the core 100 and the ceramic layer 300 may be a combination of a hydrophobic material. Through this, the shell 200 can be formed more stably.

As such, since the nanoparticles 10 have a core-shell structure, the nanoparticles 10 have dispersibility in the additive dispersed in the base oil, and even if the additive is mixed in different oils, the nanoparticles ( 10) The dispersibility can be maintained stably.

In one embodiment, the average particle diameter (D ₅₀ ) of the nanoparticles 10 may be 100 to 200 nm.

If the average particle diameter of the nanoparticles 10 exceeds 200 nm, the size of the nanoparticles 10 becomes too large and agglomeration occurs, making it unable to sufficiently perform its function as the nanoparticles 10. If the particle diameter is less than 100 nm, it cannot function as an additive, so it is preferable that the average particle diameter (D50) of the nanoparticles 10 is 100 nm to 200 nm.

In one embodiment, the nanoparticles 10 may be mixed with 0.1 wt% or less of the base oil in the lubricating oil composition for electric vehicles, in one example, 0.01 to 0.1 wt%, and in another example, 0.03 wt%. It may be mixed at 0.07 wt%, in another example, 0.03 to 0.05 wt%, and in another example, 0.05 wt%.

If the nanoparticles (10) are mixed in an amount of 0.1 wt% or more based on the weight of the base oil, the ratio of the nanoparticles (10) in the base oil may increase excessively, causing an increase in viscosity, so mix within the above numerical range. It is desirable to be

In one embodiment, the lubricating oil composition for electric vehicles may further include other additives depending on the purpose. Other additives include antioxidants, cleaning dispersants, viscosity index improvers, pour point lowering agents, oiliness improvers, and anti-foaming agents.

Figure 4 is a conceptual diagram to explain the tendency of nanofluids to improve thermal conductivity. Hereinafter, the principle of improving the thermal conductivity of the lubricant composition for electric vehicles provided by an embodiment of the present invention will be explained with reference to FIG. 4.

Nanofluid refers to a fluid in which nanoparticles are dispersed, and an example is a lubricant composition for electric vehicles provided by an embodiment of the present invention.

In Figure 4, T _h is the temperature of the high-temperature section, T ⁿ _L is the temperature of the low-temperature section when heat is transferred through the nanofluid, and T ^f _L is the temperature of the low-temperature section when heat is transferred through the general fluid. The smaller the slope of the graph, the smaller the temperature difference between the high-temperature section and the low-temperature section, and at this time, the heat transfer rate can be said to be fast.

Referring to Figure 4, the temperature change of the general fluid (T _h → T ^f _L ) decreases almost linearly, while the temperature change of the nanofluid (T _h → T ⁿ _L ) changes in slope in the area where nanoparticles exist. There is. More specifically, it can be seen that the core region of the nanoparticle where the nanodiamonds are placed has an almost horizontal thermal conductivity, while the shell region where the surface treatment agent is placed has a predetermined temperature gradient. At this time, the slope of the temperature gradient in the shell area has a lower slope than the slope of the external temperature gradient.

Accordingly, nanofluids have a faster heat conduction rate than regular fluids. This is because, for example, nanodiamonds, such as the particles in Figure 2, are materials with excellent thermal conductivity, so the heat transfer rate within the nanodiamond particles is greatly increased, thereby improving the overall heat transfer performance of the nanofluid.

Figure 5 is a cross-sectional view schematically showing the dispersion state of an additive containing conventional nanodiamonds and an additive according to an embodiment of the present invention. Figure 5 (A) shows the dispersion state when general nanodiamonds are added to base oil, and (B) shows the dispersion state of a lubricant composition containing the nanoparticles of Figure 2 according to an embodiment of the present invention. It was done.

Hereinafter, the dispersion stability of the electric vehicle lubricant composition provided by an embodiment of the present invention will be described with reference to FIG. 5.

According to Figure 5 (A), conventional nanodiamonds tend to aggregate to form aggregates rather than being dispersed as individual particles. Due to the aggregates, the dispersion of the nanodiamonds decreases, the number of particles increases toward the bottom rather than the top of the solution, and precipitation may occur.

On the other hand, as shown in Figure 5 (B), in the lubricant composition containing nanoparticles 10 according to an embodiment of the present invention, the nanoparticles 10 are provided with a hydrophobic shell 200 on the surface. Since the nanoparticles 10 are dispersed, agglomeration and precipitation of the nanoparticles 10 do not occur, and the nanoparticles 10 undergo Brownian motion and can be uniformly dispersed in the lubricant.

In one embodiment, the lubricating oil composition according to one embodiment of the present invention can uniformly disperse the base oil and nanoparticles 10, and when used in an electric vehicle, the base oil and nanoparticles are dispersed within the motor and reducer. (10) can be distributed uniformly throughout.

In addition, in this way, it is possible to secure the dispersion stability of the nanoparticles 10 in the lubricant even over time, and thus the performance of the lubricant can be improved even if the idle time during which the electric motor is not driven during the process of parking or stopping the electric vehicle is prolonged. can be maintained.

Meanwhile, it is predicted that the coolant market in the future electric vehicle market will likely be replaced by the cooling oil market. The lubricant composition provided by an embodiment of the present invention has high thermal conductivity and provides a high cooling function, as will be described later, and can be used as a composition for electric vehicle coolant in the future coolant market.

In addition, referring again to Figure 1, the electric motor (1) and reducer (2) of a future electric vehicle may be formed as separate parts, or the electric motor (1) and reducer (2) may be formed as one inseparable part. In some cases, it is built-in, but the lubricant composition provided by an embodiment of the present invention can be used universally in both, and can provide a lubricant composition that can be used in multiple electric vehicles in a single process, thereby improving process convenience. can be provided.

Hereinafter, production examples and experimental examples of the present invention will be described. However, these manufacturing examples and experimental examples are intended to explain the configuration and effects of the present invention in more detail, and the scope of the present invention is not limited thereto.

Manufacturing Example 1 - Manufacturing lubricant applied to electric vehicles.

In this Preparation Example 1, a lubricating oil composition for electric vehicles was prepared, and the specific manufacturing process was as follows.

After dissolving nanodiamonds and surface treatment agent in 5L of hexane, stir to form a mixture.

At this time, Preparation Examples 1.1 to 1.3 were prepared by mixing the total amount of nanodiamonds and surface treatment agent in the ratio shown in Table 1 below.

entry Ratio of nanodiamonds and surface treatment agent to base oil weight (wt%) Manufacturing Example 1.1 0.03 Manufacturing Example 1.2 0.05 Manufacturing Example 1.3 0.1

Afterwards, the mixture was formed into a dispersion using dispersion equipment.

Afterwards, the solvent of the dispersion was replaced with base oil, and ATF SP4M-1 from Michang Petrochemical Company was used as the base oil.

Manufacturing example 2

In this Preparation Example 2, an electric vehicle lubricant composition containing nanoparticles including ceramic particles was prepared.

As a specific method, an electric vehicle lubricant composition was prepared in the same manner as Preparation Example 1, except that SiO ₂ was further included.

At this time, SiO ₂ was added to 25 wt% based on the total weight of the nanoparticles, and through this, an electric vehicle lubricant composition was successfully manufactured.

Experimental Example 1 - Experiment to confirm thermal conductivity of lubricant composition applied to electric vehicles.

In this Experimental Example 1, an experiment was conducted to confirm the thermal conductivity of the electric vehicle lubricant composition prepared through Preparation Example 1 and Preparation Example 2.

The thermal conductivity confirmation experiment of Experimental Example 1 was conducted using the TPS method, and the lubricating oil compositions of Preparation Examples 1.1 to 1.3 and the conventional lubricating oil composition (referring to the oil to be compared in Figure 6, hereinafter, comparison) Example 1) was tested by repeating measurements 6 times, and the average value of the 6 test results was obtained.

Figure 6 is a diagram showing the results of an experiment confirming the thermal conductivity of the electric vehicle lubricant composition prepared through Preparation Example 1.

Referring to Figure 6, Comparative Example 1 had a thermal conductivity of 0.2055 W/m·K, while the lubricant of Preparation Example 1.1 had an experimental result of 0.2193 W/m·K, and the lubricant of Preparation Example 1.2 had an experimental result of 0.2312 W/m. ·K, the lubricant of Production Example 1.3 gave an experimental result of 0.2246W/m·K.

In addition, as a result of checking the thermal conductivity of the electric vehicle lubricant composition containing nanoparticles including the ceramic layer prepared through Preparation Example 2 in the same manner, 0.24 W/m·K was obtained, which showed that through Preparation Example 2 It can be seen that the prepared electric vehicle lubricant composition can provide superior thermal conductivity than the electric vehicle lubricant composition prepared through Preparation Example 1.

It can be seen that the lubricating oil composition according to the present invention has improved thermal conductivity compared to conventional lubricating oil compositions, and can provide an excellent cooling effect for mechanical devices. Furthermore, since the lubricant cools quickly, thermal oxidation of the lubricant can be delayed, and the lifespan of the lubricant can also be extended.

Experimental Example 2 - Confirmation experiment of friction coefficient of lubricant composition applied to electric vehicles

In this Experimental Example 2, an experiment was conducted to confirm the friction coefficient of the electric vehicle lubricant composition prepared through Preparation Example 1.2, and an experiment was conducted to compare and confirm it with the lubricant composition of Comparative Example 1.

As for the specific experimental method, the experiment was conducted using reciprocating mode test and evaluation equipment, and the load was 200N and the reciprocating frequency was 15Hz at room temperature conditions. The procedure lasted 30 minutes and was performed using a 2.3 mm stroke.

As a result of the experiment, it was found that Comparative Example 1 had a friction coefficient of 0.08, while the electric vehicle lubricant composition prepared through Preparation Example 1.2 had a friction coefficient as low as 0.05.

Through this, the lubricating oil composition according to the present invention has a significantly lower coefficient of friction, thereby solving the problem of the formation of by-products such as particles due to friction with the pipes through which the lubricating oil flows while passing through the electric motor of an electric vehicle. Able to know.

Experimental Example 3 - Experiment to confirm dispersion stability of lubricant composition applied to electric vehicles

In this Experimental Example 3, an experiment was conducted to confirm the long-term dispersion stability of the lubricant composition for electric vehicles prepared through Preparation Example 1.2, and a lubricant composition made by dispersing unsurfaced nanodiamonds in mineral oil (Comparative Example 2) ) and an experiment were conducted to compare and confirm its performance.

Figures 7 and 8 are diagrams showing long-term dispersion stability test results for a conventional additive containing nanodiamonds and a lubricating oil composition according to an embodiment, respectively.

For the long-term dispersion stability test, the LUMiSizer Dispersion analyzer, a dispersion stability analysis equipment, was used, and the analysis was performed in an environment with a temperature of 45°C and a humidity of 30%.

LUMiSizer includes a NIR light source and a centrifuge device. The cell filled with the sample is rotated at high speed to accelerate the sedimentation speed of the dispersed particles. At the same time, when NIR light is radiated to the entire cell, some is absorbed by the sample and the rest is transmitted. By continuously measuring this transmitted light with an NIR sensor, a transmission profile can be obtained. Through the permeation profile, the change in permeability of the solution according to particle sedimentation can be seen. The transmission profile measures increasingly higher permeability because as particles settle to the bottom of the cell, the number of particles present at the top of the cell decreases.

Since one transmission profile (one line graph) represents the transmittance measured at regular intervals, the interval between profiles means the moving distance of particles during a certain period of time. Therefore, by dividing the interval between profiles by the measurement time interval, the movement speed of the particles (μm/s) can be calculated.

Figure 7 is a permeation profile of a conventional lubricant, and Figure 8 is a permeation profile of a lubricant composition according to an embodiment of the present invention. The sedimentation rate and dispersion stability of each sample can be determined by comparing the distance traveled by each transmission profile in the transmission profile when the sample is rotated at 2000 rpm and the transmission profile when the sample is rotated at 4000 rpm.

Comparing Figures 7 and 8, it can be seen that the moving distance of the transmission profile of Figure 8 is smaller than that of Figure 7. This means that the nanoparticles rarely undergo particle sedimentation in the lubricating oil, and thus their dispersibility is maintained for a long period of time.

By providing a lubricant composition for electric vehicles with such high dispersion stability, the lifespan of the lubricant composition can be improved.

In addition, even when the idle period is prolonged due to the electric vehicle not being driven for a long period of time, the lubricant composition according to the present invention can effectively provide a lubricating function during the initial operation of the electric vehicle, thereby preventing problems that occur during the initial operation of the electric vehicle. can be prevented.

Experimental Example 4 - Confirmation experiment of viscosity of lubricant composition applied to electric vehicles

In this Experimental Example 4, an experiment was conducted to check the viscosity using the lubricating oil composition prepared through Preparation Example 1.2.

The experimental results of this Experimental Example 4 are summarized in Table 2 below.

Test Items unit Test result Test Methods Kinematic viscosity (100℃) cSt 5.430 ASTM D445-21 Kinematic viscosity (40℃) cSt 22.22 ASTM D445-21 Viscosity Index - 196 ASTM D2270-10(2016)

As can be seen from Table 2 above, even if nanoparticles are added according to the present invention, the viscosity of the electric vehicle lubricant composition is no different from that of the existing lubricant composition.

Considering Experimental Examples 1 to 4, it is possible to provide high thermal conductivity and a low coefficient of friction while maintaining low viscosity, and the lubricant composition for electric vehicles provided by the present invention provides a low coefficient of friction. As a result, the amount of heat generated when moving pipes in an electric vehicle can be minimized, and by increasing the thermal conductivity of the lubricant, a high cooling function can be performed, increasing the driving distance of the electric vehicle and further improving the lifespan of the battery. It can provide the desired effect.

In addition, by providing a lubricant composition for electric vehicles with high wear resistance with improved thermal conductivity, it is possible to improve the performance of the motor and the lifespan of electric vehicle parts by cooling the motor of the electric vehicle, and reduce wear of parts. And lubrication performance can also be improved due to the ball bearing effect.

In addition, by providing a lubricating oil composition for electric vehicles with high dispersion stability, it is possible to provide a lubricating oil composition for electric vehicles with a longer lifespan.

Figure 9 is a flow chart showing a method for manufacturing a lubricant composition for an electric vehicle provided by an embodiment of the present invention.

Referring to Figure 9, in order to solve the above technical problem, another embodiment of the present invention includes a stirring step (S100) of stirring nanoparticles, a surface treatment agent, and a solvent together to form a mixture, and dispersing the mixture to form a dispersion liquid. A dispersion step of forming (S200); and a solvent replacement step (S300) of replacing the organic solvent of the dispersion with base oil, wherein the dispersion step includes a first dispersion step and a second dispersion step performed in succession, and the second dispersion step includes: The energy applied in the step is greater than the energy applied in the first dispersion step.

The stirring step (S100) is a step of forming a mixture by stirring the nanoparticles, surface treatment agent, and solvent together.

In one embodiment, the stirring step (S100) includes a dissolving step (S10) of dissolving the nanocarbon particles and the surface treatment agent in an organic solvent, and stirring the organic solvent in which the precursor compound and the surface treatment agent are dissolved, forming the core (100). ) and a stirring step (S20) of forming a mixture containing nanoparticles 10 including the shell 200.

In one embodiment, the nanocarbon particles may include nanodiamonds.

In one embodiment, the surface treatment agent includes an unsaturated fatty acid.

In one embodiment, the surface treatment agent may further include an amine-based compound.

After the nanocarbon particles and the surface treatment agent are dissolved together in an organic solvent (S10), and the organic solvent in which the nanocarbon particles and the surface treatment agent are dissolved is stirred (S20), the surface treatment agent forms a shell (shell) on the surface of the nanocarbon particles. A reaction to form a 200) layer and proceed with surface treatment proceeds.

In one embodiment, the surface treatment agent may chemically bond with a functional group on the surface of the ceramic layer 300 or a functional group on the surface of the core 100 and may further include a surface treatment material that has hydrophobicity.

In one embodiment, the surface treatment material may be an alkyl silane compound including alkoxy silane and epoxy silane.

In one embodiment, the surface treatment material may be an organic compound having an oxygen-containing functional group such as a carboxyl group (-COOH), a hydroxyl group (-OH), a ketone (-CO-), an amino group, and a thiol group.

In one embodiment, the surface treatment material may be a linear polymer, for example, copolymers such as ethylene vinyl acetate (EVA), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), etc. You can do it.

In one embodiment, the surface treatment material may be a linear polymer containing a ring, for example, a linear polymer containing a ring such as polyaniline, polypyrrole, etc.

In one embodiment, the surface-treated nanocarbon particles refer to nanoparticles 10 and include a core 100 and a shell 200 surrounding the core 100, and the shell (200) means that the surface treatment agent was formed through reaction.

Detailed descriptions of the unsaturated fatty acids and amine compounds are replaced with the descriptions in the above-described examples.

In one embodiment, the organic solvent may be a hydrocarbon-based organic solvent, and the hydrocarbon-based organic solvent may include, for example, at least one of saturated hydrocarbons, unsaturated hydrocarbons, and aromatic hydrocarbons.

In one embodiment, the organic solvent is a C ₅ to C ₁₀ substituted/unsubstituted saturated hydrocarbon, a C ₅ to C ₁₀ substituted/unsubstituted unsaturated hydrocarbon, and a C ₅ to C ₁₀ substituted/unsubstituted aromatic hydrocarbon. It may include any one or more selected from the group consisting of.

The saturated hydrocarbons include, for example, hexane, pentane, 2-ethyl hexane, heptane, decane, cyclohexane, etc., the unsaturated hydrocarbons include, for example, hexene, heptene, cyclohexene, etc., and the aromatic hydrocarbons include, for example, Examples include toluene, xylene, decalin, 1,2,3,4-tetrahydronaphthalene, etc.

In one embodiment, the stirring is not particularly limited, and any stirring method that can be selected by a person skilled in the art should be construed as falling within the scope of the present invention.

In this step, a dispersion is formed by dispersing the mixture containing nanoparticles 10 surface-treated with a surface treatment agent prepared in the stirring step (S100).

In this step, the aggregated nanoparticles 10 are physically broken down into small units.

The present invention has the advantage of shortening the manufacturing time by stirring and then dispersing the nanocarbon particles, surface treatment agent, and organic solvent from the beginning, unlike existing manufacturing methods that perform dispersion and then stirring.

In one embodiment, the dispersion step (S200) may include a first dispersion step (S210) and a second dispersion step (S220) performed sequentially.

In one embodiment, the energy applied in the second dispersion step (S220) may be greater than the energy applied in the first dispersion step (S210).

In one embodiment, the first dispersion step and the second dispersion step are each independently carried out by a paint shaker, ball mill, bead mill, homogenizer, NP mill, underwater counter collision, high-speed desiccant, grinder, high-pressure homogenizer. , dispersion may be carried out using any one of a high-pressure impact grinder, a disk-type refiner, a conital refiner, a two-axis kneader, a multi-axis kneader, an automatic mill, a homomixer, an ultrasonic disperser, and a beater.

In this solvent replacement step (S300), the organic solvent of the dispersion is replaced with base oil.

In this step (S300), the organic solvent may be replaced with base oil to correspond to the product to be finally used. The base oil is replaced with the detailed description in the above embodiment.

In this step (S300), the organic solvent of the dispersion may be replaced with base oil, and the specific method is not particularly limited, and a solvent replacement method that can be easily selected by those skilled in the art is All of them should be interpreted as falling within the scope of rights of the present invention.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (10)

In a lubricant composition for an electric vehicle including a motor and reducer,
base oil; and
Including nanoparticles dispersed in the base oil,
The nanoparticle includes a core and a shell surrounding the core,
The shell contains unsaturated fatty acids,
The shell further includes a ceramic layer surrounding the core,
A lubricating oil composition for an electric vehicle, wherein the ceramic layer is surface treated with the unsaturated fatty acid. According to paragraph 1,
A lubricating oil composition for an electric vehicle, wherein the core includes nanocarbon particles. According to paragraph 1,
The shell further includes an amine-based compound, a lubricating oil composition for an electric vehicle. delete According to paragraph 1,
The lubricating oil composition for an electric vehicle, wherein the ceramic layer further includes an amine-based compound. According to paragraph 1,
A lubricating oil composition for an electric vehicle, wherein the ceramic layer includes a plurality of ceramic particles. According to paragraph 1,
The base oil is a lubricating oil composition for an electric vehicle in which the nanoparticles are uniformly dispersed within the motor and the reducer. According to paragraph 1,
A lubricant composition for an electric vehicle, wherein the nanoparticles have an average particle diameter of 100 to 200 nm in the motor and the reducer. According to paragraph 1,
The nanoparticles are mixed in an amount of 0.1 wt% or less of the base oil inside the motor and reducer. According to paragraph 1,
The lubricating oil composition for electric vehicles further includes at least one of an antioxidant, a cleaning dispersant, a viscosity index improver, an oiliness improver, and an anti-foaming agent.