Patent Application
20240327744
This disclosure relates to an electric vehicle (EV) lubricants and additives.
The EV transmission fluid specifications are changing rapidly with the EV industry. Currently, the majority commercial EV transmission, gearbox, or drive systems containing an electric motor or single speed transmission. Transmission fluid in EV's is much different than the fluid found in combustion engines. Due the performance of the EV's drive system, the fluid needs to be able to withstand large fluctuations in power and torque while compatible with yellow metals and coating materials.
The summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
Due the performance of the EV's drive system, the fluid needs to be able to withstand large fluctuations in power and torque while compatible with yellow metals and coating materials.
In some aspects, an electric vehicle lubricant formulation is provided that includes: a Group II to V base oil, an oxidation inhibitor, and an anti-wear or extreme pressure additive. This formulation has superior copper corrosion and extreme pressure at high temperatures and extremely low electrical conductivity than commercially available products.
Other methods, features and/or advantages is, or will become, apparent upon examination of the following figures and detailed description. It is intended that all such additional methods, features, and advantages be included within this description and are protected by the accompanying claims.
An EV fluid formulation is designed from the individual ingredients to give advantages in each area of EV fluid requirements. The lubrication system needs to reduce friction and wear and increase extreme pressure protection and yellow metal compatibility. There are many moving parts in the EV transmission, such as gears, bearings, seals and electric motor. EV fluids are designed to be compatible with yellow metals (copper), electrical components, high loads and high temperatures. EV fluids are designed to fill for life and have a higher resistance to thermal breakdown. This particular EV fluid is specially formulated to meet the unique demands of the electric transmission in light duty and heavy duty EVs.
EV fluid can be formulated with any mineral and synthetic base oils (group I to V). For lower viscosities, synthetic base oils are preferred as they can provide higher thermal and oxidative stability than mineral oils. Also, viscosity modifiers (VM) s to help boost the viscosity index may be added. The battery cooling is very challenging with high-speed components and tiny gaps. Battery parts must be lubricated to function efficiently and improve the battery life.
In some aspects, an electric vehicle lubricant formulation is provided that includes: a Group II or III or IV or V base oil, an oxidation inhibitor, and an anti-wear or extreme pressure additive. This formulation is required to have the following properties to provide a load wear index of between about 40 to about 55 in a Four ball EP test, provide between about 0 ppm to about 30 ppm of copper in fluid as measured by ASTM D130 @150° C., 168 hr, and provide an electrical conductivity of between about 10 pS/m@20° C. and 1750 pS/m@20° C. as measured by ASTM D2624. This formulation is unique in the combination of characteristics as described. In particular this formulation handles extreme pressure and high load conditions at least as well as commercially available products however has high temperature copper corrosion protection unlike those commercially available products and yet even further provides an electrical conductivity that this lower than commercially available products.
In some aspects, the electric vehicle lubricant formulation includes additional additives that may be a viscosity modifier, pour point depressant, corrosion inhibitor, foam suppressant, or combination thereof.
In some aspects, the electric vehicle lubricant formulation includes a Group IV or V base oil is present in an amount between about 70 wt % and 99 wt %.
In some aspects, the electric vehicle lubricant formulation includes a anti-wear or extreme pressure additive is present in an amount between about 0.001 wt % to about 10 wt %.
In some aspects, the electric vehicle lubricant formulation includes MoDTC as an oxidation inhibitor.
In some aspects, the electric vehicle lubricant formulation includes the oxidation inhibitor is present in an amount between about 0.001 wt % to about 5 wt %.
In some aspects, the electric vehicle lubricant formulation includes: 98-99.8 wt % of a Group II to IV base oil, a Group V base oil, or a combination of a Group II to V base oils, wt % oxidation inhibitor, and wt % an anti-wear or extreme pressure additive. This formulation is characterized by between about 0 ppm to about 128 ppm of copper in fluid as measured by ASTM D130@150° C., 168 hr or provides an electrical conductivity of between about 10 pS/m@20° C. and 1750 pS/m@20° C. as measured by ASTM D2624 or provide used oil foam as measured by ASTM D892 is less than 50/0 for all three sequences.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the present specification, including definitions, will control.
Unless otherwise specified, “a,” “an,” “the,” “one or more of,” and “at least one” are used interchangeably. The singular forms “a”, “an,” and “the” are inclusive of their plural forms. “h” and “hr” refer to hour or hours.
The recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 0.1 to 5 includes 0.01, 0.05, 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).
The term “about,” when referring to a value or to an amount of mass, weight, time, volume, concentration, or percentage is meant to encompass variations of +1.5% from the specified amount. The terms “comprising” and “including” are intended to be equivalent and open-ended. The phrase “consisting essentially of” means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method. The phrase “selected from the group consisting of” is meant to include mixtures of the listed group.
Moreover, the present disclosure also contemplates that in some aspects, any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed singularly or in any combination.
Weight percent: All weight (and mass) percents expressed herein (unless otherwise indicated) are based on overall composition weight.
The base oil of the electric vehicle lubricant formulation includes a Group II, III, IV or V base oil. Preferable the base oil of the electric vehicle lubricant formulation includes a Groups I, II, III, IV, or V base oil or a blend of Groups I, II, III. IV, or V base oils, or include a Groups II, III, IV, or V base oil or a blend of Groups II, III. IV, or V base oils. Preferably the base oil is present in an amount of between about 70 wt % and 99.8 wt %, or an amount between about 89 wt % and about 99.7 wt %, or about 98 wt % to about 99.8 wt %, or a single value that falls within the range between about 70 wt % and 99.8 wt %, for example, 92.55 wt %, 94 wt %, or 99 wt %.
Preferably the electric vehicle lubricant formulation includes an oxidation inhibitor. In some aspects, the oxidation inhibitor is diisotridecylamine molybdate, or MoDTc. Preferably the oxidation inhibitor is present in an amount of between about 0.001 wt % and 10 wt %, or an amount between about 0.1 wt % and 10 wt %, or about 0.1 wt % to about 5 wt %, or a single value that falls within the range between about 0.001 wt % and 10 wt %, for example, 0.5 wt % or 1.0 wt %.
Preferably the electric vehicle lubricant formulation includes anti-wear (AW) or extreme pressure (EP) additives based on ashless phosphate esters. Such as those of the general formula:
Preferably the anti-wear (AW) or extreme pressure (EP) additive is present in an amount of between about 0.001 wt % and 10 wt %, or an amount between about 0.1 wt % and 10 wt %, or about 0.1 wt % to about 5 wt %, or a single value that falls within the range between about 0.001 wt % and 10 wt %, for example, 0.4 wt %, 0.5 wt % or 4.0 wt %.
In some aspects, a viscosity modifier, pour point depressant, corrosion inhibitor, a foam suppressant or other additive is added to the formulation. Preferably the a viscosity modifier, pour point depressant, corrosion inhibitor, a foam suppressant or other additive, collectively, is present in an amount of between about 0.001 wt % and 10 wt %, or an amount between about 0.1 wt % and 10 wt %, or about 0.1 wt % to about 5 wt %, or a single value that falls within the range between about 5.1 wt %, 2.45 wt %, or 0.1 wt %.
The additives may be added individually or as an additive package.
In some aspects the additive package may be in the form of a concentrate that is diluted to supply the final formulation.
In some aspects, the formulation of the instant invention, while maintaining optimal performance under extreme pressure and high load conditions, additionally provides excellent copper corrosion protection at high temperatures. That is, in the ASTM D 130@ 150° C. for 168 hours provided significantly less copper in the fluid as measured by the ASTM D130 test. In some aspects, the amount of copper found in the fluid as measured by this test is zero ppm.
In other aspects, the amount of copper found in the fluid as measured by this test is significantly below that of commercially available EV fluids. In other aspects, the amount of copper found in the fluid as measured by this test is between about 128 ppm and about 0 ppm. In other aspects, the amount of copper found in the fluid as measured by this test is less than 130 ppm. In other aspects, the amount of copper found in the fluid as measured by this test is between 128 ppm and 0 ppm. In other aspects, the amount of copper found in the fluid as measured by this test is about 55 ppm, or about 50 ppm, or about 30 ppm, or about 25 ppm, or about 20 ppm, or about 15 ppm, or about 10 ppm, or about 0 ppm.
In some aspects, the formulation of the instant invention, while maintaining optimal performance under extreme pressure and high load conditions, additionally provides the property of a low electrical conductivity. In some aspects, the formulation of the instant invention has an electrical conductivity that is identical to that of commercially available EV fluids. In some aspects, the formulation of the instant invention has an electrical conductivity that is less than or equal to about 1700 pS/m@20° C. In some aspects, the formulation has an electrical conductivity that is between about 100 pS/m@ 20° C. and about 1700 pS/m@20° C. In some aspects, the formulation has an electrical conductivity that is between about 10 pS/m@20° C. and about 1800 pS/m@20° C. In some aspects, the formulation has an electrical conductivity that is between 10 pS/m@20° C. and 1800 pS/m@20° C.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to preferred aspects and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alteration and further modifications of the disclosure as illustrated herein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
It is important to choose each ingredient that is compatible with transmission materials and will not cause any damage over the vehicle life.
As a starting point, the formulation should include: anti-wear/Extreme pressure additives such as Gear oils, Hydraulic fluids, Metal working fluids, Turbine oils, or Greases. Examples include Afton Hitec® 312, Afton Hitec® 307, Afton Hitec® 10000, Lubrizol ADDCO™ 360-P, Lubrizol Anglamol 33, Lubrizol 5069, BASF Irgalube® 353, Clariant Hostaphat® 1322, Hostacor® ITD. Other additives may include: Oxidation inhibitor/antioxidant, Foam suppressants/antifoam, corrosion inhibitor. The formulation with also include base oils: Group I to V, or any combination or blend thereof.
The main ingredient is an ashless extreme pressure additive with low foam and strong emulsification properties. Phosphate esters can also offer excellent extreme pressure and anti-wear properties.
Formulation examples are provided in Table 1:
Table 1 expressed ingredients in a wt %. In the formulation, the Kinematic viscosity@100° C. can vary from 2 cSt to 15 cSt, EP/AW additive treat rate varies from 0.001 wt % to 10 wt % and Oxidation inhibitor: MoDTC preferred.
The electric motor applies a large torque instantly that can cause a lot of loads on the gears and bearings. Our special EV fluid is formulated to handle these large loads and provide the best-in-class wear protection for the transmission. In Table 2 comparing standard automatic transmission fluids (ATFs), EV specific additive-based fluids (ETF) and exemplary EV fluids of Examples 1, 2, or 3.
Dexron® and Mercon® are standard ATFs used in EV transmissions. We have referenced two extreme examples of ETFs where Load wear index (LWI) varied based on the Sulphur concentration. ETF 2 don't have any Sulphur or low Sulphur. All three examples showed significant improvements over ATFs and ETFs.
Generally, it is very difficult and chemically impossible to have both excellent extreme pressure performance and excellent copper corrosion. And we achieved this with our EV fluid formulation where we have a very good copper corrosion rating (ASTM D130) for a 7 day very high temperature test. Table 3 demonstrates rating and copper ppm in fluid.
Example 3 is a special performance to get 0 ppm or no copper dissolved in the fluid. Examples 2 and 3 also show a very strong performance where there is negligible copper dissolved.
Referring to
It is important have lower electrical conductivity of fluids because of concerns about safety and discharge of static electricity.
For a new oil: ATF specification define max 50/0 for all three sequences
The extensive durability test runs at different speeds and torques to simulate demanding conditions in EVs for a week. The oil will experience high speed shearing and instant torque-speed changes and depicts 200,000+miles in real life driving. The used oil after the extensive testing was evaluated where Example 2 showed performance and contaminants didn't impact the foam. This is a very important parameter as this affects the oil life where transmission oils are generally offered fill for life. Both commercial ATF and ETF don't pass the ATF specification when tested as used oils.
The complete disclosure of all patents, patent applications, and publications, and electronically available material cited herein are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.
This application claims benefit of U.S. Provisional Application No. 63/492,812, filed Mar. 29, 2023, entitled Electric Vehicle Lubricants and Additives which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63492812 | Mar 2023 | US |
