Dielectric thermal control fluid and method of use thereof

Abstract

More specifically, the present disclosure provides dielectric thermal management fluids suitable for use in managing heat in battery systems via direct cooling, such as lithium-ion batteries used in electric vehicles, electric motors, and power electronics, methods of using such thermal management fluids, and systems including such thermal management systems. The present disclosure relates generally to administration fluids for thermal management of medical devices. More specifically, the present disclosure relates to medical devices. Electrical thermal management fluids suitable for use in managing heat in battery systems through direct cooling. Applications include devices used in lithium ion battery electric vehicles, electric motors, electronics and methods of using such thermal management fluids, and systems including such thermal management systems.

Description

Technical Field

[0001] This invention generally relates to thermal management fluids. More specifically, the present disclosure relates to a dielectric thermal management fluid suitable for use in managing heat within a battery system via direct cooling, such as in lithium-ion batteries used in electric vehicles, electric motors, and power electronics, methods of using such thermal management fluids, and systems including such thermal management systems.

Background Art

[0002] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 153,148, filed Feb. 24, 2021, which is hereby incorporated by reference in its entirety.

[0003] The worldwide sales of electric vehicles (i.e., vehicles that use electricity for all or part of their motive power, such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.) have been increasing over the past several years and are expected to continue to increase. Ultimately, it is likely that the majority of vehicles will be electric. As electric vehicle technology continues to evolve, there is a need to provide improved power sources (e.g., battery systems or modules). For example, it is desirable to increase the distance such vehicles can travel without the need to recharge the battery, improve the performance of such batteries, and reduce the costs and time associated with battery charging.

[0004] Most batteries generate heat when current is supplied to or drawn from them. Generally, as the amount of current flowing into or out of the battery increases, so does the amount of heat generated. If the generated heat is not dissipated, the battery temperature rises. Most batteries have an effective operating temperature range, and if the battery exceeds its maximum operating temperature, it may become inoperable or even suffer thermal runaway and failure. In some cases, after a slight rise in temperature, the battery may be able to dissipate heat into its surroundings through a simple heatsink or without thermal management. In other cases, a more specific thermal management system is required to dissipate the heat generated by the battery.

[0005] Currently, battery-powered electric vehicles almost without exception use lithium-ion battery technology. While lithium-ion batteries offer many advantages over comparable nickel-metal hydride batteries, they are more susceptible to temperature fluctuations and therefore have more stringent thermal management requirements. For example, the optimal operating temperature for lithium-ion batteries is in the range of 10-35°C. As the temperature rises from 35°C to 70°C, operation becomes increasingly inefficient, and more importantly, operation at these temperatures can damage the battery over time. Temperatures above 70°C indicate an increased risk of thermal runaway. As a result, lithium-ion batteries require a specific thermal management system to regulate their temperature during vehicle operation. Also, during charging, up to 10% of the input power can be converted into heat. As fast charging of lithium-ion batteries becomes more common, an efficient system for battery thermal management remains necessary.

[0006] Lithium-ion batteries can be cooled directly or indirectly using a thermal management fluid (i.e., a cooling fluid or coolant) to carry heat away from the battery components. Direct cooling is advantageous because it allows the thermal management fluid to come into direct contact with the hot components and carry heat away from them. In indirect cooling, the hot components are electrically shielded by an electrically insulating barrier, and the thermal management fluid carries away the heat that passes through this barrier. The most common thermal management fluids are based on a mixture of water and glycol. However, these fluids typically conduct electricity and cannot be used for the direct cooling of the electrical components of lithium-ion batteries. Indirect cooling allows the use of water-based coolants, but the requirement for electrical shielding can create a bottleneck in the heat flow in the cooling process. There are dielectric thermal management fluids that can be used for the direct cooling of electrical components due to their non-conductive properties, examples of which have been conventionally used for cooling transformers. However, the thermal properties of such dielectric thermal management fluids are typically inferior compared to water-glycol. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Therefore, there is still a need for improved dielectric thermal management systems, particularly those suitable for use in cooling lithium-ion batteries. [Means for solving the problem]

[0008] One aspect of the present disclosure provides a thermal management fluid having a flash point of at least 100°C and a dielectric constant of at least 1.5 at 25°C, as measured according to ASTM D93. Such dielectric thermal management fluids include: One or more dielectric compounds of formula (1)

[0009] [ka] m is an integer, either 1, 2, or 3; n is an integer, either 1, 2, 3, 4, 5, 6, 7, or 8; R1 is a C6-C12 alkyl group; R2 is a C6-C12 alkyl group; Each Rs and Ra is independently selected from H and C1-C6 alkyl groups; each Rs and Re is independently selected from H and C1-C6 alkyl groups; The one or more dielectric compounds are present in a total amount ranging from 1% by weight to 100% by weight, based on the total weight of the thermal management fluid, and the thermal management fluid is a thermal management fluid.

[0010] Another aspect of the present disclosure provides a battery system. The battery system includes a housing, one or more electrochemical cells disposed within the housing, a fluid path extending within the housing and substantially in thermal communication with the one or more electrochemical cells, and a thermal management fluid as described herein disposed within the fluid path.

[0011] In another embodiment, the Disclosure provides an electric vehicle comprising the battery system of the Disclosure described herein.

[0012] In another embodiment, the Disclosure provides a thermal management circuit comprising a fluid path extending around and / or through a heat source, and a thermal management fluid of the Disclosure, disposed within the fluid path, circulating within the fluid path, and configured to absorb thermal energy generated by the heat source, wherein the fluid is disposed within the fluid path, a heat exchanger, a pump, and connecting ducts.

[0013] Another aspect of the present disclosure provides a method comprising bringing the thermal management fluid of the present disclosure into contact with a surface having a temperature of at least 25°C (e.g., at least 30°C), wherein the surface is substantially in thermal communication with a heat source, and absorbing thermal energy from the heat source into the thermal management fluid through the surface.

[0014] Another aspect of the present disclosure provides a method for preparing the thermal management fluid of the present disclosure. Such a method relates to a compound of formula (II).

[0015] [ka] m is an integer, either 1, 2, or 3; n is an integer 1, 2, 3, 4, 5, 6, 7, or 8; The method involves each Ra, R4, Rs, and Re being independently selected from H and C1-C6 alkyl groups and reacting with (C6-C12 alkyl)-L (wherein L is a leaving group) to obtain a dielectric compound of formula (I).

[0016] The accompanying drawings are included to provide a further understanding of the compositions and methods of this disclosure, are incorporated herein, and constitute part thereof. The drawings are not necessarily to a constant scale, and the sizes of various elements may be distorted for clarity. The drawings illustrate one or more embodiments of this disclosure and, together with the description, serve to illustrate the principles and operations of this disclosure. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic cross-sectional view of a thermal management circuit according to one embodiment of the present disclosure. [Figure 2] This is a schematic cross-sectional view of a thermal management circuit according to another embodiment of the present disclosure. [Modes for carrying out the invention]

[0018] The inventors have noted that desirable heat management fluids often have a high ability to carry away heat within the temperature range associated with the operation of certain electrical devices or systems (e.g., lithium-ion batteries), and further have a sufficiently high dielectric constant to be suitable for use in direct cooling of the device or system. Importantly, since there is always a risk of oxygen entering the overall system, it is advantageous for the desirable heat management fluid to have a high flash point to reduce the risk of ignition. Also, to provide more efficient heat transfer during operation, the desirable heat management fluid preferably has a low viscosity that allows for better fluidity in a particular electrical device or system.

[0019] The inventors have identified a heat management fluid composition that not only provides a desirable low viscosity but also has a high flash point, and thus can be easily pumped through a system with a low or no risk of ignition. Specifically, the inventors have recognized that conventional dielectric fluids (e.g., organic or silicone) typically have good thermal conductivity and specific heat capacity but have an undesirably high viscosity. However, typical low-viscosity dielectric fluids generally have an unacceptably low flash point (and other ignition characteristics) and are not suitable for use as a coolant in systems where there is a potential for temperature rise where ignition is a risk. The inventors have found that the dielectric compounds of the present disclosure can provide a heat management fluid that does not have a low flash point and preferably has a low viscosity. These properties of the heat management fluid make them particularly suitable for, for example, direct cooling of electrical devices and systems.

[0020] The heat management fluids and methods of the present disclosure can have several additional advantages over conventional fluids. In particular, the heat management fluids of the present disclosure can also provide one or more of a desirably high thermal conductivity, a low risk of ignition, a high dielectric constant, and a rapid temperature response in various embodiments. The heat management fluids of the present disclosure can also have a lower surface tension than conventional low-viscosity dielectric fluids in various embodiments.

[0021] Thus, one aspect of the present disclosure provides a thermal management fluid comprising one or more dielectric compounds of formula (I), wherein the one or more dielectric compounds are present in a total amount ranging from 1 wt% to 100 wt%. Such a thermal management fluid can have a flash point of at least 100 °C as measured according to ASTM D93 ("Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester") and a dielectric constant of at least 1.5 at 25 °C.

[0022] Since there is always some risk that oxygen may enter the system, the thermal management fluids of the present disclosure preferably have a high flash point to prevent ignition. As described above, the thermal management fluids of the present disclosure can have a flash point of at least 100 °C as measured according to ASTM D93. For example, in various embodiments, the thermal management fluids described herein can have a flash point of at least 110 °C, such as at least 120 °C, at least 125 °C, at least 130 °C, or at least 135 °C as measured according to ASTM D93. In various embodiments, the thermal management fluids described herein can have a flash point of at least 140 °C, such as at least 145 °C, at least 150 °C, at least 155 °C, at least 160 °C, or at least 165 °C as measured according to ASTM D93. Materials that do not have a flash point below 100 °C are considered to have a flash point above 100 °C for the purposes of the present disclosure, even if the flash point cannot be measured for the material (i.e., due to decomposition).

[0023] Low viscosity is often desirable for thermal management fluids to facilitate pumping of the thermal management fluid through the system, especially when relatively narrow passages are used. Those skilled in the art will, based on this disclosure, select components to provide a thermal management fluid having a desired viscosity so that it can be conveniently conducted through the system. Accordingly, in various embodiments, the thermal management fluids described elsewhere herein have a kinematic viscosity at 40°C in the range of 1.5 to 10 cSt, as measured according to ASTM D455, for example, 1.5 to 8 cSt, or 2 to 6 cSt, or 2 to 10 cSt, or 2 to 15 cSt, or 3 to 10 cSt, or 3 to 15 cSt, or 5 to 20 cSt, or 5 to 10 cSt, or 8 to 10 cSt. Accordingly, in various embodiments, the thermal management fluids described herein separately have a kinematic viscosity at 40°C in the range of 1.5 to 10 cSt, for example, 1.5 to 8 cSt, or 1.5 to 6 cSt, or 2 to 10 cSt, or 2 to 10 cSt, or 2 to 6 cSt, or 3 to 10 cSt, or 3 to 8 cSt, or 3 to 6 cSt, or 5 to 10 cSt, or 5 to 8 cSt, or 5 to 6 cSt, or 6 to 10 cSt, or 8 to 10 cSt, as measured according to ASTM D. Furthermore, in various embodiments, the thermal management fluids described herein separately have a kinematic viscosity in the range of 1.5 to 5 cSt at 40°C, measured according to ASTM D455, for example, 1.5 to 4 cSt, or 1.5 to 3 cSt, or 2 to 5 cSt, or 2 to 4 cSt, or 2 to 3 cSt, or 3 to 5 cSt, or 3 to 4 cSt, or 4 to 5 cSt.

[0024] The thermal management fluids of this disclosure are preferably dielectric so that they can be used for direct cooling applications. Therefore, they have a dielectric constant of at least 1.5 when measured at 25°C. The dielectric constant is measured using the coaxial probe method according to ASTM D924. In various embodiments, the thermal management fluids of this disclosure have a dielectric constant of at least 1.75, e.g., at least 2.0, or at least 2.25 when measured at 25°C. In various embodiments, the thermal management fluids of this disclosure have a dielectric constant in the range of 1.5 to 10, e.g., 1.8 to 10, or 1.5 to 2.8, or 1.8 to 2.8.

[0025] In various embodiments of the present disclosure, the thermal management fluid of the present disclosure may have a density of 1.1 g / cm³ or less at 25°C. For example, in various embodiments of the present disclosure, the thermal management fluid of the present disclosure may have a density of 1 g / cm³ or less at 25°C.

[0026] In various embodiments of the present disclosure, the thermal management fluid of the present disclosure may have a heat capacity of at least 1 J / gK, or at least 1.2 J / gK, or even further at least 1.5 J / gK at 25°C. In various embodiments of the present disclosure, the thermal management fluid of the present disclosure may have a thermal conductivity in the range of 0.05 W / m·K to 1 W / m·K at 25°C. In various embodiments of the present disclosure, the thermal management fluid of the present disclosure may have a coefficient of thermal expansion of 1100 × 10⁻⁶ / K or less (e.g., 1050 × 10⁻⁶ / K or less, or 1000 × 10⁻⁶ / K or less).

[0027] As described above, the thermal management fluid of this disclosure comprises one or more dielectric compounds of formula (I).

[0028] In various embodiments, in one or more dielectric compounds of formula (I) as separately described herein, R1 is a C6-C10 alkyl, for example, a C6-C8 alkyl. In various embodiments of the dielectric compounds of formula (1) of this disclosure, R1 is a C8-C12 alkyl, for example, a C8-C10 alkyl or a C10-C12 alkyl. In various embodiments of the dielectric compounds of formula (I) of this disclosure, R is a branched C6-C12 alkyl such as a branched C6-C10 alkyl, a branched C6-C8 alkyl, a branched C8-C12 alkyl, a branched C8-C10 alkyl, or a branched C10-C12 alkyl. The branching may be, for example, at the α- or β-position relative to the oxygen atom to which R1 is bonded. In various embodiments, the branching is at the p- position relative to the oxygen atom. For example, in a particular compound of formula (I), R1 is a p-branched C6-C12 alkyl group, such as a p-branched C6-C10 alkyl group, a p-branched C6-C8 alkyl group, a p-branched C8-C12 alkyl group, a p-branched C8-C10 alkyl group, or a p-branched C10-C12 alkyl group.

[0029] In one or more dielectric compounds of formula (I) as otherwise described herein, R2 is a C6-C10 alkyl, for example, a C6-C8 alkyl. In various embodiments of the dielectric compounds of formula (I) of this disclosure, R2 is a C8-C12 alkyl, such as a C8-C10 alkyl or a C10-C12 alkyl. In various embodiments of the dielectric compounds of formula (I) of this disclosure, R2 is a branched C6-C12 alkyl, such as a branched C6-C10 alkyl, a branched C6-C8 alkyl, a branched C8-C12 alkyl, a branched C8-C10 alkyl, or a branched C10-C12 alkyl. The branching may be located, for example, at the α- or β-position relative to the oxygen atom to which R2 is bonded. In various embodiments, the branching is at the P-position relative to the oxygen atom. For example, in a particular compound of formula (I), R2 is a p-branched C6-C12 alkyl group, such as a p-branched C6-C10 alkyl group, a p-branched C6-C8 alkyl group, a p-branched C8-C12 alkyl group, a p-branched C8-C10 alkyl group, or a p-branched C10-C12 alkyl group.

[0030] In various embodiments, in one or more dielectric compounds of formula (I) described herein, each of Ra, Ra', Rs, and Re is independently selected from H and C1-C4 alkyl (e.g., C1-C3 alkyl or C1-C2 alkyl). In certain other embodiments, each of R3, R4, R5, and R6 is independently selected from H and C1 alkyl (i.e., methyl).

[0031] In various embodiments described separately herein, in one or more dielectric compounds of formula (I), each of R3, R4, Rs, and Re is H, i.e., the compound has formula:

[0032] [ka]

[0033] In various embodiments, in one or more dielectric compounds of formula (I) as separately described herein, R4, R5, and R6 are each H, and R3 is H or C1-C6 alkyl. For example, in some embodiments, each of R4, R5, and R6 is H, and R3 is a C1-C6 alkyl (e.g., C1-C4 alkyl, C1-C3 alkyl, ethyl, or methyl), that is, the compound has the formula.

[0034] [ka] In various embodiments, R4, R5, and R6 are each independently H, and R3 is a C1-C6 alkyl group (e.g., C1-C4 alkyl, C1-C3 alkyl, ethyl, or methyl).

[0035] In various embodiments, in one or more dielectric compounds of formula (I) as separately described herein, n is an integer 1 or 2. In various embodiments, n is an integer 2 or 3. In various embodiments, n is an integer 1, i.e., the compound has formula:

[0036] [ka] In various embodiments, one or more dielectric compounds are given by formula:

[0037] [ka] In various embodiments, one or more dielectric compounds are given by formula:

[0038] [ka] In various embodiments, n is an integer 2, i.e., the compound is given by formula:

[0039] [ka] It holds.

[0040] In various embodiments described separately herein, in one or more dielectric compounds of formula (I), m is 1. However, in other embodiments, m is 2 or m is 3.

[0041] In various embodiments described separately herein, in one or more dielectric compounds of formula (I), m is an integer 1 or 2, and n is 1.

[0042] In various embodiments described separately herein, one or more dielectric compounds of formula (1) m is an integer, either 1, 2, or 3; n is 1; R1 is a C6-C12 alkyl group; R2 is a C6-C12 alkyl group; Rs is H or C1-C3 alkyl; R4, R5, and R6 are independently H.

[0043] In various embodiments described separately herein, one or more dielectric compounds of formula (I) m is an integer, either 1, 2, or 3; n is 1; R1 is a C6-C10 alkyl group; R2 is a C6-C10 alkyl group; R3 is H and C1-C3 alkyl; R4, R5, and R6 are independently H.

[0044] In various embodiments described elsewhere herein, one or more dielectric compounds of formula (I) contain a total number of carbon atoms of 14 to 50 (e.g., 14 to 40, 14 to 30, 14 to 20, 16 to 50, 16 to 40, 16 to 30, 16 to 20, 18 to 50, 18 to 40, 18 to 30, 18 to 20, 20 to 50, 20 to 40, or 20 to 30). For example, in various embodiments, one or more dielectric compounds of formula (I) contain a total number of carbon atoms of 18 to 22. In various embodiments, one or more dielectric compounds of formula (I) contain a total number of carbon atoms of 16 to 22. In various embodiments, one or more dielectric compounds of formula (I) contain a total number of carbon atoms of 14 to 20.

[0045] In various embodiments described separately herein, one or more compounds of formula (I) have a structure.

[0046] [ka] In the formula, Ra and Ro are each independently methyl or ethyl, and Rc and Rd are each independently C3-C7 alkyl, for example C4-C6 alkyl. In certain such embodiments, m is 1. In other such embodiments, m is 2.

[0047] In various embodiments described separately herein, one or more compounds of formula (I) have a structure.

[0048] [ka] In the formula, Ra and Rb are each independently methyl or ethyl, and Rc and Rd are each independently C3-C8 alkyl, e.g., C3-C7 alkyl, C3-C6 alkyl, or C4-C6 alkyl. In certain such embodiments, m is 1. In other such embodiments, m is 2.

[0049] In various embodiments described separately herein, one or more compounds of formula (I) have a structure.

[0050] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C8 alkyl, e.g., C3-C7 alkyl, C4-C6 alkyl, or C1-C6 alkyl. In certain such embodiments, m is 1. In other such embodiments, m is 2.

[0051] In various embodiments described separately herein, one or more compounds of formula (I) have a structure.

[0052] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Ra are independently C3-C8 alkyl, e.g., C3-C7 alkyl, C3-C6 alkyl, or C4-C6 alkyl. In certain such embodiments, m is 1. In other such embodiments, m is 2.

[0053] In various embodiments described separately herein, one or more compounds of formula (I) have a structure.

[0054] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C8 alkyl, e.g., C3-C7 alkyl, C3-C6 alkyl, or C4-C6 alkyl. In certain such embodiments, m is 1. In other such embodiments, m is 2.

[0055] Examples of compounds of formula (1) as disclosed herein include, but are not limited to, the following.

[0056] [ka]

[0057] In various embodiments, one or more of the dielectric compounds of formula (1) are 1,2-bis((2-ethylhexyl)oxy)ethane of formula:

[0058] [ka]

[0059] In various embodiments described separately herein, one or more dielectric compounds of the thermal management fluid have a flash point of at least 140°C as measured according to ASTM D93. The inventors have advantageously determined that the use of dielectric compounds of the present disclosure having high flash points can provide an overall thermal management fluid with a high flash point, thereby reducing the risk of ignition. In various embodiments of the thermal management fluid described separately herein, one or more dielectric compounds have a flash point of at least 145°C (e.g., at least 150°C, at least 155°C, at least 150°C, or at least 165°C) as measured according to ASTM D93.

[0060] The inventors have advantageously determined that one or more dielectric compounds described herein have relatively low viscosity but a reduced risk of ignition. Accordingly, in various embodiments of the thermal management fluids described herein, one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 2 to 10 cSt, as measured according to ASTM D455, for example, 2 to 8 cSt, or 2 to 6 cSt, or 3 to 10 cSt, or 3 to 8 cSt, or 3 to 6 cSt, or 5 to 10 cSt, or 5 to 8 cSt, or 5 to 6 cSt, or 6 to 10 cSt, or 8 to 10 cSt. Therefore, in various embodiments of the thermal management fluid described separately herein, one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 2 to 10 cSt, as measured according to ASTM D, for example, 2 to 8 cSt, or 2 to 6 cSt, or 3 to 10 cSt, or 3 to 8 cSt, or 3 to 6 cSt, or 5 to 10 cSt, or 5 to 8 cSt, or 5 to 6 cSt, or 6 to 10 cSt, or 8 to 10 cSt. Also, in various embodiments of the thermal management fluid described separately herein, one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 2 to 5 cSt, or 2 to 4 cSt, or 2 to 3 cSt, or 3 to 5 cSt, or 3 to 4 cSt, or 4 to 5 cSt, as measured according to ASTM D455.

[0061] Those skilled in the art will understand that various combinations of the dielectric compounds of this disclosure can be used in the thermal management fluids of this disclosure. Accordingly, the embodiments of the dielectric compounds described above can be combined in any number and any combination in the thermal management fluids of this disclosure. When two or more dielectric compounds are used in the thermal management fluid, the relative amounts of the two can be varied according to the disclosures herein, depending on the desired effect. In various embodiments, the mass ratio of the first dielectric compound to the second dielectric compound is in the range of 1:9 to 9:1 (e.g., 1:5 to 5:1, or 1:5 to 1:1, or 1:1 to 5:1).

[0062] One or more dielectric compounds may be present in varying amounts in the thermal management fluid described herein. In various embodiments described separately herein, one or more dielectric compounds are present in a total amount ranging from 1% to 100% by weight (e.g., 5% to 100% by weight, or 10% to 100% by weight, or 20% to 100%) based on the total weight of the thermal management fluid. For example, in various embodiments of thermal management fluids as otherwise described herein, one or more dielectric compounds are present in a total amount ranging from 1% to 99.9% by weight (e.g., 5% to 99.9% by weight, or 10% to 99.9% by weight, or 20% to 99.9% by weight), or 50% to 99.9% by weight, for example, 75% to 99.9% by weight, or 85% to 99.9% by weight, or 90% to 99.9% by weight, or 95% to 99.9% by weight, or 98% to 99.9% by weight, based on the total weight of the thermal management fluid. In various embodiments of the thermal management fluid described separately herein, one or more dielectric compounds are present in a total amount ranging from 1% to 99% by weight (e.g., 5% to 99% by weight, or 10% to 99% by weight, or 20% to 99% by weight), or 50% to 99% by weight, for example, 75% to 99% by weight, or 85% to 99% by weight, or 90% to 99% by weight, or 95% to 99% by weight, based on the total weight of the thermal management fluid.In various embodiments of the thermal management fluid described herein, one or more dielectric compounds are present in a total amount ranging from 1% to 85% by weight (e.g., 5% to 85% by weight, or 10% to 85% by weight, or 20% to 85% by weight), or 50% to 85% by weight, e.g., 65% to 85% by weight, or 75% to 85% by weight, based on the total weight of the thermal management fluid. Those skilled in the art will provide, based on the disclosure herein, a dielectric compound in an amount that provides the thermal management fluid with a desired high flash point in addition to any other desired properties (e.g., viscosity).

[0063] As those skilled in the art will understand, the thermal management fluids of this disclosure may also include various other components, such as those conventional in compositions for thermal management applications. For example, the thermal management fluid may further include oils, such as mineral oils, synthetic oils, or silicone oils. For example, in various embodiments, the oil is a low viscosity group II, III, IV, or V base oil as defined by the American Petroleum Institute (API Publication 1509). These are shown in Table 1. Table 1 - Base Oil Stock API Guidelines

[0064] [Table 1]

[0065] Group II and Group III base oils (e.g., hydrocracking and hydrotreated base oils, as well as synthetic oils, e.g., hydrocarbon oils, polyalphaolefins, alkyl aromatic compounds, and synthetic esters), and Group IV base oils (e.g., polyalphaolefins (PAO)) are well known base oils. Oils suitable for use as transformer oils may, in many embodiments, be suitable for use in the compositions, systems, and methods of the Disclosure. For example, esters also form useful base oil raw materials, including synthetic esters, as well as GTL (gas-liquid) materials, particularly those derived from hydrocarbon sources. For example, esters of dibasic acids and monoalcohols, or polyol esters of monocarboxylic acids may be useful as base stocks of the Disclosure.

[0066] In various embodiments, the thermal management fluid of the Disclosure further comprises a base oil of Group II, Group III, Group IV, or Group V. For example, in various embodiments, the thermal management fluid of the Disclosure further comprises a base oil of Group II or Group III. In certain other embodiments, the thermal management fluid of the Disclosure further comprises a Group IV base oil such as polyalphaolefin (PAO). In some other embodiments, the thermal management fluid of the Disclosure further comprises an ester base oil stock.

[0067] In various embodiments, the thermal management fluid of this disclosure further comprises one or more of the following: corrosion inhibitors, antioxidants (such as phenolic and amine antioxidants), pour point depressants, defoamers, defoamers, viscosity index modifiers, preservatives, biocides, surfactants, seal swelling additives, and combinations thereof. In various embodiments, corrosion inhibitors and antioxidants (such as phenolic and amine antioxidants) may be used. For example, antioxidants (e.g., oxidizers), pour point depressants, defoamers, defoamers, viscosity index modifiers, preservatives, biocides, surfactants, seal swelling additives, and combinations thereof may be present in an amount of up to 5.0% by weight based on the total weight of the thermal management fluid. In certain such embodiments, one or more of the following are present based on the total weight of the thermal management fluid: corrosion inhibitors, antioxidants (such as phenolic and amine antioxidants), pour point depressants, defoamers, defoamers, viscosity index modifiers, preservatives, biocides, surfactants, seal swelling additives, and combinations thereof, in amounts ranging from 0.2% to 5.0% by weight, for example, 1.0% to 2.0% by weight, or 0.2% to 1.0% by weight, or 0.2% to 0.5% by weight, or 0.05% to 0.2% by weight. In various embodiments, the thermal management fluid of the present disclosure further includes one or more flame retardants in amounts up to 20% by weight, up to 10% by weight, or up to 5% by weight, for example, based on the total weight of the thermal management fluid. However, in other embodiments, flame retardant properties are absent.

[0068] Another aspect of the present disclosure provides a method comprising bringing a thermal management fluid described herein into contact with a surface having a temperature of at least 25°C, wherein the surface is substantially in thermal communication with a heat source, and absorbing thermal energy in the thermal management fluid from the heat source through the surface.

[0069] Contact between the thermal management fluid and the surface can be dynamic or static (i.e., conductive). For example, in various embodiments, contact between the thermal management fluid and the surface can be achieved by circulating the fluid over the surface, for example, by pumping or by other means. In various embodiments, contact can also be achieved without circulation, for example, by bringing the thermal management fluid, which is a stationary fluid, into contact with the surface.

[0070] The surface temperature may vary; the thermal management fluid may be adapted for use at various temperatures. In various embodiments described separately herein, the surface temperature is in the range of 25°C to 150°C, for example, 25°C to 100°C, or 25°C to 90°C, or 25°C to 85°C, or 25°C to 80°C, or 25°C to 75°C, or 25°C to 70°C. In various embodiments described separately herein, the surface temperature is in the range of 30°C to 150°C, for example, 30°C to 100°C, or 30°C to 90°C, or 30°C to 85°C, or 30°C to 80°C, or 30°C to 75°C, or 30°C to 70°C. In various embodiments described separately herein, the surface temperature is in the range of 40°C to 150°C, for example, 50°C to 150°C, or 60°C to 150°C, or 70°C to 150°C, or 80°C to 150°C, or 90°C to 150°C, or 100°C to 150°C, or 110°C to 150°C. In various embodiments described separately herein, the surface temperature is in the range of 50°C to 150°C, for example, 50°C to 140°C, or 50°C to 130°C, or 50°C to 120°C, or 50°C to 110°C, or 50°C to 100°C, or 50°C to 90°C, or 50°C to 80°C. In various embodiments (and at specific times during the operation of the device or system), the surface temperature is below the boiling point of one or more dielectric compounds of formula (I) of the thermal management system. In various embodiments, through contact, each of the one or more dielectric compounds of formula (I) does not reach its boiling point.

[0071] Embodiments of the method of the present disclosure are shown with reference to Figure 1. A thermal management circuit 100 is shown in a schematic side cross-sectional view of Figure 1. The thermal management circuit 100 includes a thermal management fluid 120 that circulates through the circuit and passes over a surface 142. The temperature of the surface 142 rises compared to the temperature of the thermal management fluid 120. As a result, thermal energy is absorbed from the surface 142 into the thermal management fluid 120.

[0072] In various embodiments, as otherwise described herein, the method includes generating thermal energy by operating electrical components. For example, a thermal management circuit 100 is associated with an electrical component 140 that generates heat during operation. In various embodiments, heat is generated as an element of charging and discharging of electrical components. As will be understood by those skilled in the art, inefficiencies in the operation of electrical components and resistance of circuits generate heat as current passes through the circuits and elements of the electrical components. For example, heat from the operation of electrical component 140 raises the temperature of the surface 142, resulting in the transfer of thermal energy to the thermal management fluid 120. In other embodiments, thermal energy is generated by chemical reactions, such as exothermic reactions, or by friction. In yet another embodiment, the thermal management fluid is cooled and absorbs thermal energy from its surface at ambient temperature or slightly higher.

[0073] In various embodiments as otherwise described herein, the electrical component includes a battery system, capacitors, inverters, electrical cables, fuel cells, motors, or computers. For example, in various embodiments, the electrical component is a battery system comprising one or more electrochemical cells arranged in a housing. In other embodiments, the electrical component is one or more capacitors, such as electrolytic capacitors or electric double-layer capacitors, e.g., supercapacitors. In yet another embodiment, the electrical component is one or more fuel cells, such as polymer electrolyte membrane fuel cells, direct methanol fuel cells, alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, or reversible fuel cells. In various embodiments, the electrical component is an electric motor. In other embodiments, the electrical component is a computer, e.g., a personal computer or server. Furthermore, in yet another embodiment, the electrical component is a high-power charging device.

[0074] The electrical components of the present invention can operate on direct current (DC) or alternating current (AC). In various embodiments as separately described herein, the electrical components operate on DC or AC voltages greater than 48 V. In various embodiments as separately described herein, the electrical components operate on DC or AC voltages greater than 100 V, greater than 200 V, or greater than 300 V.

[0075] In various embodiments as otherwise described herein, the surface is the surface of an electrical component. For example, in Figure 1, the housing 150 of the electrical component 140 includes a reservoir of thermal management fluid 120. Elements of the electrical component, including certain circuits that generate heat, are immersed in the thermal management fluid 120, and the thermal management fluid directly absorbs thermal energy from the outer surface 142 of the electrical component 140.

[0076] In various embodiments described elsewhere in this specification, the surface is the inner surface of the conduit. For example, Figure 2 shows a thermal management circuit 200 including an electrical component 240 comprising a plurality of individual units 244. In particular, the electrical component 240 is a battery comprising a plurality of electrochemical cells 244. The electrical component 240 further includes a conduit 246 extending between the electrochemical cells 244 through the interior of the electrical component. When the electrical component generates thermal energy, the inner surface 242 of the conduit 246 is heated, and the thermal energy is absorbed by the thermal management fluid 220.

[0077] In various embodiments as otherwise described herein, the conduits pass through a housing surrounding electrical components. For example, a conduit 246 in a thermal management circuit 200 extends through an opening 252 in a housing 250 surrounding electrical components 240, thereby allowing the thermal management fluid 220 to be delivered to other elements of the thermal management circuit 200.

[0078] Another aspect of the present disclosure provides a battery system comprising a housing, one or more electrochemical cells disposed within the housing, a fluid path extending through the housing and substantially in thermal communication with one or more electrochemical cells, and a thermal management fluid disposed within the fluid path according to any of the embodiments described above. For example, the thermal management circuit 200 in Figure 2 includes a battery system 210. The battery system includes a plurality of electrochemical cells 244 disposed inside a housing 250. A conduit 246 forms a fluid path extending through the housing. A thermal management fluid 220 disposed within the conduit 246 is thereby arranged to be in thermal communication with the electrochemical cells 244. When the electrochemical cells 244 charge and discharge, they generate heat, which is absorbed by the thermal management fluid 220. In various embodiments, the electrochemical cells undergo rapid charging, which generates a large amount of heat. The high thermal capacity of the thermal management fluid allows it to absorb this large amount of heat as soon as it is generated.

[0079] In various embodiments as otherwise described herein, the fluid path is at least partially defined by a cavity in the housing. For example, in various embodiments, at least a portion of the fluid path is formed between the electrochemical cell and the inner wall of the housing, as is the fluid path 122 within component 140.

[0080] In various embodiments as otherwise described herein, the fluid path is at least partially defined by at least one conduit located within the housing. For example, in the battery system 210, conduit 246 provides a fluid path 222 through the housing 250.

[0081] In various embodiments described separately herein, the electrochemical cell is a lithium-ion electrochemical cell. In other embodiments, the electrochemical cell is a solid cell, a lithium sulfur cell, a lithium iron phosphate cell, a lithium-ion polymer cell, a sodium ion cell, an aluminum ion cell, a lead acid cell, or a magnesium ion cell.

[0082] In various embodiments as otherwise described herein, the battery system is a component of an electric vehicle. In some embodiments, the electric vehicle is a fully electric vehicle or a hybrid electric vehicle. In other embodiments, the battery system is a component of a power motor, such as an electric motor or a motor in power electronics. In other embodiments, the battery system is part of a home energy storage solution that works in conjunction with a stationary energy storage solution, such as a local renewable energy source like a solar panel or wind turbine.

[0083] Another aspect of the present disclosure provides a thermal management circuit including a fluid path extending around and / or through a heat source, and a thermal management fluid according to any of the embodiments described above, which is located within the fluid path, circulates within the fluid path, and is configured to absorb thermal energy generated by the heat source, the fluid being located within the fluid path, a heat exchanger, a pump, and a connecting duct. For example, the thermal management circuit 100 shown in Figure 1 includes a fluid path 122 extending around an electrical component 140. The thermal management fluid 120 flows through the path 122 and absorbs thermal energy from the electronic component 140. From the fluid path 122, the thermal management fluid 120 flows through a first duct 130 to a heat exchanger 160. The thermal energy stored in the thermal management fluid 120 is removed from the fluid in the heat exchanger 160 before the fluid flows through the second duct 132 to the pump 170. After the pump 170, the thermal management fluid 120 passes through the third duct 134 and returns to the fluid path 122 surrounding the electrical components 140. The circuit 100 shown in Figure 1 is a schematic diagram of a simple embodiment using the described thermal management fluid. In other embodiments, the thermal management circuit includes additional elements such as valves, pumps, heat exchangers, reservoirs, and any combination of ducts.

[0084] In various embodiments as otherwise described herein, the heat source is a battery comprising a plurality of electrochemical cells, and the fluid path passes between at least two of the electrochemical cells.

[0085] In various embodiments, as otherwise described herein, the fluid path is defined by a housing surrounding an electrical component. For example, the housing 150 in Figure 1 surrounds an electrical component 140 and provides a cavity for a thermal management fluid 120. The electrical component 140 is held within the housing at a certain distance from the walls of the housing 150, thereby enabling the formation of a path for the thermal management fluid 120 between the housing 150 and the electrical component 140. The housing 150 has a closed shape with a specific opening 152 that provides access for the thermal management fluid 120, but in other embodiments, the top of the housing is open and the thermal management fluid is held within the housing by gravity.

[0086] In various embodiments as otherwise described herein, the fluid path is configured to arrange a thermal management fluid that is substantially in thermal communication with the electrical component in order to absorb the thermal energy generated by the electrical component. For example, in the thermal management circuit 100, the fluid path 122 extends around the electrical component 140 and is in direct contact with the surface of the electrical component 140. Furthermore, in the thermal management circuit 200, the fluid path 222 passes through a conduit 246 that extends adjacent to the elements of the electrical component 240. In both cases, the fluid path is positioned so that the thermal management fluid is close to the electrical component so that the thermal management fluid can easily absorb thermal energy from the component.

[0087] In various embodiments as otherwise described herein, the thermal management circuit further includes a fluid path and a heat exchanger in fluid communication, wherein the thermal management fluid is configured to circulate between the fluid path and the heat exchanger to dissipate heat through the heat exchanger. In various embodiments as otherwise described herein, the heat exchanger is configured to remove heat from the thermal management fluid. For example, in the thermal management circuit 100, after the thermal management fluid 120 is pumped out from the housing 150, the thermal management fluid 110 proceeds to the heat exchanger 160, where the thermal energy is transferred to a cooler fluid such as ambient air or a coolant.

[0088] In various embodiments described separately herein, the thermal management circuit includes a battery system according to any of the embodiments described above. For example, thermal management circuit 200 includes a battery system 210. In various embodiments described separately herein, the thermal management circuit includes a fixed desiccant material arranged according to any of the embodiments described above. For example, thermal management circuit 300 includes a battery desiccant material 360.

[0089] The details shown herein are, for illustrative purposes only, for the purpose of illustrating various embodiments of the invention and are presented to provide what is considered to be the most useful and readily understandable explanation of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt has been made to show structural details of the invention in more detail than is necessary for a basic understanding of the invention, and the explanations provided with the drawings and / or examples will make it clear to those skilled in the art how some forms of the invention can actually be embodied. Therefore, before the processes and devices disclosed are described, it should be understood that the aspects described herein are not limited to specific embodiments, apparatus, or configurations, and are therefore naturally subject to change. It should also be understood that the terms used herein are intended solely to describe specific embodiments and are not intended to limit them unless specifically defined herein.

[0090] In the context describing the present invention (particularly in the context of the following embodiments and claims), the terms “a,” “an,” “the,” and similar reference subjects should be interpreted as encompassing both singular and plural unless otherwise indicated herein or unless the context clearly contradicts this interpretation.

[0091] As used herein, the term “alkyl” means a linear or branched hydrocarbon containing 1 to 12 carbon atoms, unless otherwise specified. Representative examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. When the “alkyl” group is a linking group between two other parts, it may be linear or branched, and examples include, but are not limited to, -CH2-, -CHaCH2-, -CH2CH2CHC(CH3)-, and -CH2CH(CH2CH3)CH2-.

[0092] All methods described herein may be carried out in any preferred order of steps, unless otherwise indicated herein or unless the context clearly contradicts it. Any and all examples or exemplary language provided herein (e.g., "etc.") are intended solely to better illustrate the invention and not to impose any limitation on the scope of the claimed invention. No language herein should be construed as indicating any unclaimed element essential to the practice of the invention.

[0093] Unless the context clearly indicates otherwise, the word “comprise” throughout this specification and the claims means “comprise.” Words such as “comprising” should be interpreted in a comprehensive sense, as opposed to an exclusive or exhaustive sense; that is, “including, but not limited to.” Words used in the singular or plural also include the plural and singular, respectively. Furthermore, the words “in this specification,” “above,” and “below,” and words of similar meaning, when used in this application, refer to the entire application and not to any particular part thereof.

[0094] As those skilled in the art will understand, each embodiment disclosed herein includes, essentially consists of, or may consist of, the specific described elements, steps, components, or constituents. Where used herein, the transitional clauses “comprise” or “comprises” mean “include,” but are not limited to, and allow for the inclusion of unspecified elements, steps, components, or constituents, even in large numbers. The transitional clause “consists of” excludes any unspecified elements, steps, components, or constituents. The transitional clause “essentially consists of” limits the scope of the embodiment to specific elements, steps, components, or constituents, and those that do not substantially affect the embodiment.

[0095] All percentages, ratios, and proportions in this specification are given by weight unless otherwise specified.

[0096] While the numerical ranges and parameters representing the broad scope of this disclosure are approximations, the numerical values ​​shown in specific examples are reported as accurately as possible. However, each numerical value inherently contains a certain degree of error that inevitably arises from the standard deviation found in their respective test measurements.

[0082] The grouping of alternative elements or embodiments of this disclosure should not be construed as limiting. Members of each group may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in or removed from a group for convenience and / or patentability reasons. In any event of such inclusion or removal, this specification shall be deemed to include the modified groups and thus satisfy the described descriptions of all Markush groups used in the appended claims.

[0097] Several embodiments of various aspects of this disclosure, including the best mode known to the inventors for carrying out the methods described herein, are described herein. Naturally, variations of these described embodiments will be apparent to those skilled in the art by reading the foregoing description. Those skilled in the art will use such variations as appropriate, and therefore the methods of this disclosure can be carried out in ways other than those specifically described herein. Accordingly, the scope of this disclosure includes all modifications and equivalents of the subject matter described in the claims attached herein, as permitted by applicable law. Furthermore, any combination of the above elements in all possible variations thereof is encompassed by this disclosure unless otherwise indicated herein or unless it is clearly inconsistent with the context. Examples

[0098] The methods of this disclosure are further illustrated by the following examples, which should not be construed as limiting the scope or spirit of this disclosure to the specific procedures and compounds described therein. Preparation of the dielectric compound of formula (I)

[0099] The compounds of this disclosure can be readily prepared from inexpensive starting materials such as diols, as shown in Scheme 1.

[0100] [ka] In the formula, R1 to R6, m and n are as defined herein, R is R1 or R2 as defined herein, and L is a leaving group.

[0101] [ka]

[0102] To a solution of 2-((2-ethylhexyl)oxy)ethane-1-ol (151 g, 0.87 mol, 1.0 equivalent) in xylene (30 mL), NaOH (38 g, 0.96 mol, 1.1 equivalents) was added all at once. The resulting mixture was heated to 120°C (internal temperature) and stirred for 30 minutes. During this time, the color of the reaction mixture changed from colorless to deep reddish-purple. The reaction mixture was then treated by adding 2-ethylhexyl bromide (168 g, 0.87 mmol, 1.0 equivalent) dropwise over 5 minutes. The mixture was stirred at 120°C for 1 hour. The system was then vacuumed (approximately 400 mbar) and steady reflux of xylene into a Dean-Stark receiver was started. The reaction was maintained for 4 hours, after which 15 mL of water was collected. The reactants were returned to ambient pressure and temperature and diluted with water. The organic phase was separated, and the aqueous phase was washed with heptane (3 × 50 mL). The organic phases were combined, dried over MgSO₄, filtered, and concentrated under vacuum. The crude product was purified by vacuum distillation at 2.5 mbar to obtain 1,2-bis((2-ethylhexyl)oxy)ethane (197 g, 0.69 mol, yield 79%).

[0103] The physical properties of 1,2-bis((2-ethylhexyl)oxy)ethane were evaluated and are shown in Table 2.

[0104] [Table 2]

[0105] [Table 3]

[0106] The advantages of 1,2-bis((2-ethylhexyl)oxy)ethane are more apparent when directly compared to PAO 2 (e.g., DURASYN® 162, available from INEOS, Houston, Texas, US), which is the current standard in thermal management fluids. In particular, the viscosity of 1,2-bis((2-ethylhexyl)oxy)ethane is significantly lower than that of PAO 2 at key temperatures, namely 20°C and 40°C, while the flash points are nearly the same. Therefore, as a thermal management fluid, 1,2-bis((2-ethylhexyl)oxy)ethane provides good heat transfer, requires low pumping power due to its ultra-low viscosity, and at the same time maintains a suitable flash point to prevent sparks in battery or power electronic equipment failure events.

[0107] Other aspects of this disclosure are described with respect to the embodiments listed below, which may be combined in any form and in any number that are not technically or logically inconsistent.

[0108] Embodiment 1 is a thermal management fluid. One or more dielectric compounds of formula (I) and

[0109] [ka] m is an integer, either 1, 2, or 3; n is an integer, either 1, 2, 3, 4, 5, 6, 7, or 8; R1 is a C6-C12 alkyl group; R2 is a C6-C12 alkyl group; Each Ra and R4 is independently selected from H and C1-C6 alkyl groups; each Rs and R is independently selected from H and C1-C6 alkyl groups; The one or more dielectric compounds are present in a total amount ranging from 1% by weight to 100% by weight, based on the total weight of the thermal management fluid. A thermal management fluid having a flash point of at least 100°C as measured according to ASTM D93, and having a dielectric constant of at least 1.5 at 25°C.

[0110] Embodiment 2 relates to the thermal management fluid described in Embodiment 1, wherein each of one or more compounds contains a total number of carbon atoms of 14 to 50 (for example, 14 to 40, 14 to 30, 14 to 20, 16 to 50, 16 to 40, 16 to 30, 16 to 20, 18 to 50, 18 to 40, 18 to 30, 18 to 20, 20 to 50, 20 to 40, or 20 to 30).

[0111] Embodiment 3 relates to the thermal management fluid of Embodiment 1, wherein each of one or more compounds contains a total of 18 to 22 carbon atoms.

[0112] Embodiment 4 relates to any of Embodiments 1 to 3, wherein R1 is a C6-C10 alkyl, for example, a C6-C8 alkyl.

[0113] Embodiment 5 relates to a thermal management fluid according to any of Embodiments 1 to 3, wherein R1 is a C8-C12 alkyl, for example, a C8-C16 alkyl or a C10-C12 alkyl.

[0114] Embodiment 6 applies to any of Embodiments 1 to 3, wherein R1 is a branched C6-C12 alkyl such as branched C6-C10 alkyl, branched C6-C8 alkyl, branched C6-C12 alkyl, branched C8-C10 alkyl, or branched C10-C12 alkyl.

[0115] Embodiment 7 applies to the thermal management fluid of Embodiment 6, wherein the branching of R1 is located at the α-position relative to the oxygen atom to which R1 is bonded.

[0116] Embodiment 8 relates to any of Embodiments 1 to 7, wherein R2 is a C6-C10 alkyl, for example, a C6-C8 alkyl.

[0117] Embodiment 9 relates to a thermal management fluid of any of Embodiments 1 to 7, wherein R2 is a C1-C12 alkyl, for example, a C1-C10 alkyl or a C10-C12 alkyl.

[0118] Embodiment 10 relates to a thermal management fluid according to any one of Embodiments 1 to 7, wherein R2 is a branched C6-C12 alkyl such as a branched C6-C10 alkyl, a branched C6-C8 alkyl, a branched C8-C12 alkyl, a branched C8-C18 alkyl, or a branched C10-C12 alkyl.

[0119] Embodiment 11 relates to the thermal management fluid of Embodiment 10, wherein the branching of R2 is at the 3rd position relative to the oxygen atom to which R2 is bonded.

[0120] Embodiment 12 relates to a thermal management fluid according to any of Embodiments 1 to 11, wherein each of R3, R4, R5, and R6 is H, that is, the compound has formula (I).

[0121] [ka]

[0122] Embodiment 13 is a thermal management fluid of any of Embodiments 1 to 11, wherein R4, R5, and R6 are each H, and Ra is C1-C6 alkyl (methyl or ethyl, etc.), that is, the compound has the following formula.

[0123] [ka]

[0124] Embodiment 14 relates to a thermal management fluid according to any one of Embodiments 1 to 13, wherein n is an integer 1, 2, or 3, for example, n is an integer 1 or 2.

[0125] Embodiment 15 relates to a thermal management fluid according to any of Embodiments 1 to 10. One or more dielectric compounds have formulas 1 to 13, where n is 1, for example, one or more dielectric compounds have formulas

[0126] [ka]

[0127] Embodiment 16 relates to any of the thermal management fluids of Embodiments 1 to 13, where n is 2, and for example, one or more dielectric compounds have formula (II).

[0128] [ka]

[0129] Embodiment 17 relates to a thermal management fluid of any of Embodiments 1 to 16, wherein m is 1.

[0130] Embodiment 18 applies to any of Embodiments 1 to 16, wherein m is an integer 1 or 2 and n is 1.

[0131] Embodiment 19 targets any of the thermal management fluids of Embodiments 1 to 3. m is an integer, either 1, 2, or 3; n is 1; R1 is a C6-C12 alkyl group; R2 is a C6-C12 alkyl group; R3 is either H or C1-C3 alkyl; R4, Rs, and Re are independently H.

[0132] Embodiment 20 targets any of the thermal management fluids of Embodiments 1 to 3. m is an integer, either 1, 2, or 3; n is 1; R1 is a C6-C10 alkyl group; R2 is a C6-C8 alkyl group; R3 is either H or C1-C3 alkyl; R4, Rs, and Re are independently H.

[0133] Embodiment 21 relates to the thermal management fluid described in Embodiment 1, wherein one or more compounds of formula (I) have the structure.

[0134] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C8 alkyl, for example, C3-C7 alkyl or C3-C6 alkyl.

[0135] Embodiment 22 relates to the thermal management fluid of Embodiment 1, wherein one or more compounds of formula (I) have a structure.

[0136] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C6 alkyl such as C3-C8 alkyl or C3-C7 alkyl.

[0137] Embodiment 23 relates to the thermal management fluid of Embodiment 1, wherein one or more compounds of formula (I) have a structure.

[0138] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C8 alkyl, for example, C3-C7 alkyl or C3-C6 alkyl.

[0139] Embodiment 24 relates to the thermal management fluid of Embodiment 1, wherein one or more compounds of formula (I) have a structure.

[0140] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C6 alkyl such as C3-C8 alkyl or C3-C7 alkyl.

[0141] Embodiment 25 relates to the thermal management fluid of Embodiment 1, wherein one or more compounds of formula (I) have a structure.

[0142] [ka] In the formula, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C3-C8 alkyl, for example, C3-C7 alkyl or C3-C6 alkyl.

[0143] Embodiment 26 relates to a thermal management fluid according to any of Embodiments 21 to 25, wherein Re and Ra are each independently C4-C6 alkyl.

[0144] Embodiment 27 relates to a thermal management fluid of any of Embodiments 21 to 26, wherein m is 1.

[0145] Embodiment 28 relates to the thermal management fluid of Embodiment 1, wherein one or more dielectric compounds are independently selected from the following.

[0146] [ka]

[0147] [ka]

[0148] Embodiment 29 is based on the thermal management fluid of Embodiment 1, and the dielectric compound is

[0149] [ka] That is the case.

[0150] Embodiment 30 relates to any of the thermal management fluids of Embodiments 1 to 29, wherein one or more dielectric compounds have a flash point of at least 140°C (e.g., at least 145°C, at least 150°C, at least 155°C, at least 160°C, or at least 165°C) as measured according to ASTM D93.

[0151] Embodiment 31 relates to a thermal management fluid according to any one of Embodiments 1 to 30, wherein one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 1.5 to 20 cSt, for example, 1.5 to 15 cSt, or 2 to 20 cSt, or 2 to 15 cSt, or 3 to 20 cSt, or 3 to 15 cSt, or 5 to 20 cSt, or 5 to 15 cSt, as measured according to ASTM D455.

[0152] Embodiment 32 relates to a thermal management fluid according to any of Embodiments 1 to 30, wherein one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 1.5 to 10 cSt, for example, 1.5 to 8 cSt, or 1.5 to 6 cSt, or 2 to 10 cSt, or 2 to 8 cSt, or 2 to 6 cSt, or 3 to 10 cSt, or 3 to 8 cSt, or 3 to 6 cSt, or 5 to 10 cSt, or 5 to 8 cSt, or 5 to 6 cSt, or 6 to 10 cSt, or 8 to 10 cSt, as measured according to ASTM D455.

[0153] Embodiment 33 relates to a thermal management fluid according to any one of Embodiments 1 to 30, wherein one or more dielectric compounds have a kinematic viscosity at 40°C in the range of 1.5–5 cSt, or 1.5–4 cSt, or 1.5–3 cSt, or 2–5 cSt, or 2–4 cSt, or 2–3 cSt, or 3–5 cSt, or 3–4 cSt, or 4–5 cSt, as measured according to ASTM D455.

[0154] Embodiment 34 relates to a thermal management fluid according to any one of Embodiments 1 to 33, wherein one or more dielectric compounds are present in an amount ranging from 5% to 100% by weight, or 10% to 100% by weight, or 20% to 100% by weight, based on the total weight of the thermal management fluid.

[0155] Embodiment 35 relates to a thermal management fluid according to any one of Embodiments 1 to 33, wherein one or more dielectric compounds are present in an amount ranging from 50% to 100% by weight, for example, 75% to 100% by weight, or 85% to 100% by weight, or 90% to 100% by weight, or 95% to 100% by weight, or 98% to 100% by weight, based on the total weight of the thermal management fluid.

[0156] Embodiment 36 relates to a thermal management fluid according to any one of Embodiments 1 to 33, wherein one or more dielectric compounds are present in an amount ranging from 1% to 99.9% by weight (e.g., 5% to 99.9% by weight, or 10% to 99.9% by weight, or 20% to 99.9% by weight), or 50% to 99.9% by weight, for example, 75% to 99.9% by weight, or 85% to 99.9% by weight, or 90% to 99.9% by weight, or 95% to 99.9% by weight, or 98% to 99.9% by weight, based on the total weight of the thermal management fluid.

[0157] Embodiment 37 relates to any of the thermal management fluids of Embodiments 1 to 33, wherein one or more dielectric compounds are present in amounts ranging from 1% to 99% by weight (e.g., 5% to 99% by weight, or 10% to 99% by weight, or 20% to 99% by weight), or 50% to 99% by weight, for example, 80% to 99% by weight, or 85% to 99% by weight, or 90% to 99% by weight, or 95% to 99% by weight.

[0158] Embodiment 38 relates to any of the thermal management fluids of Embodiments 1 to 33, wherein one or more dielectric compounds are present in amounts ranging from 1% to 95% by weight (e.g., 5% to 95% by weight, or 10% to 95% by weight, or 20% to 95% by weight), or 50% to 95% by weight, for example, 75% to 95% by weight, or 85% to 95% by weight, or 1% to 85% by weight (e.g., 5% to 85% by weight, or 10% to 85% by weight, or 20% to 85% by weight), or 50% to 85% by weight, for example, 65% to 85% by weight, or 75% to 85% by weight, based on the total weight of the thermal management fluid.

[0159] Embodiment 39 relates to a thermal management fluid according to any of Embodiments 1 to 38, further comprising a base oil of Group II, Group III, Group IV, or Group V.

[0160] Embodiment 40 is a thermal management fluid of any of Embodiments 1 to 38, further comprising a base oil of Group II or Group III.

[0161] Embodiment 41 is a thermal management fluid of any of Embodiments 1 to 38, further comprising a Group IV base oil (such as polyalphaolefin (PAO)).

[0162] Embodiment 42 relates to a thermal management fluid according to any one of Embodiments 1 to 38, further comprising an ester base oil stock.

[0163] Embodiment 43 relates to a thermal management fluid according to any of Embodiments 1 to 41, further comprising, for example, up to 0.5% by weight, up to 1.0% by weight, or up to 5.0% by weight, one or more of the following: corrosion inhibitors, antioxidants (such as phenolic and amine-based antioxidants), pour point depressants, defoaming agents, viscosity index modifiers, preservatives, biocides, surfactants, seal swelling additives, flame retardants, and combinations thereof, in amounts up to 0.5% by weight, up to 1.0% by weight, or up to 5.0% by weight.

[0164] Embodiment 44 relates to a thermal management fluid according to any of Embodiments 1 to 41, further comprising one or more flame retardants in amounts, for example, up to 20% by weight, up to 10% by weight, or up to 5% by weight.

[0165] Embodiment 45 relates to any of the thermal management fluids of Embodiments 1 to 44, wherein the thermal management fluid has a flash point of at least 110°C, for example, at least 120°C, at least 125°C, at least 130°C, or at least 135°C, as measured according to ASTM D93.

[0166] Embodiment 46 relates to any of the thermal management fluids of Embodiments 1 to 44, wherein the thermal management fluid has a flash point of at least 140°C, for example, at least 145°C, at least 150°C, or at least 150°C, as measured according to ASTM D93.

[0167] Embodiment 47 relates to a thermal management fluid according to any of Embodiments 1 to 46, having a kinematic viscosity at 40°C in the range of 2 to 20 cSt, for example, 2 to 15 cSt, or 3 to 20 cSt, or 3 to 15 cSt, or 5 to 20 cSt, as measured according to ASTM D455.

[0168] Embodiment 48 relates to a thermal management fluid according to any of Embodiments 1 to 46, having a kinematic viscosity in the range of 2 to 10 cSt at 40°C, for example, 2 to 8 cSt, or 2 to 6 cSt, or 3 to 10 cSt, or 3 to 8 cSt, or 3 to 6 cSt, or 5 to 10 cSt, or 5 to 8 cSt, or 5 to 6 cSt, or 6 to 10 cSt, or 8 to 10 cSt, when measured according to ASTM D455.

[0169] Embodiment 49 relates to a thermal management fluid according to any of Embodiments 1 to 46, having a kinematic viscosity in the range of 2 to 5 cSt, or 2 to 4 cSt, or 2 to 3 cSt, or 3 to 5 cSt, or 3 to 4 cSt, or 4 to 5 cSt, when measured according to ASTM D455, at 40°C.

[0170] Embodiment 50 relates to a thermal management fluid according to any of Embodiments 1 to 49, having a dielectric constant of at least 1.75, for example, at least 2.0, or at least 2.25 when measured at 25°C.

[0171] Embodiment 51 relates to a thermal management fluid according to any of Embodiments 1 to 49, having a dielectric constant in the range of 1.5 to 10, or 1.8 to 10, or 1.5 to 2.8, or 1.8 to 2.8.

[0172] Embodiment 52 relates to a thermal management fluid according to any of Embodiments 1 to 51, having a density of 1.1 g / cm³ or less at 25°C (for example, 1 g / cm³ or less at 25°C).

[0173] Embodiment 53 applies to any of Embodiments 1 to 52, having a thermal conductivity in the range of 0.05 W / m·K to 1 W / m·K at 25°C.

[0174] Embodiment 54 relates to a thermal management fluid according to any of Embodiments 1 to 53, having a specific heat capacity of at least 1 J / g·K (for example, at least 1.2 J / g·K or at least 1.5 J / g·K at 25°C).

[0175] Embodiment 55 relates to a thermal management fluid according to any of Embodiments 1 to 52, having a thermal expansion coefficient of 1100 × 10⁻⁶ / K or less (for example, 1050 × 10⁻⁶ / K or less, or 1000 × 10⁻⁶ / K or less).

[0176] Embodiment 56 is a method that includes the following: The thermal management fluid of Embodiments 1 to 55 is brought into contact with a surface having a temperature of at least 25°C, wherein the surface is in substantially thermal communication with a heat source. The thermal energy of the heat management fluid is absorbed from the heat source through the aforementioned surface.

[0177] Embodiment 57 relates to the method of Embodiment 56, wherein the surface has a temperature of at least 30°C, for example, at least 40°C.

[0178] Embodiment 58 relates to the method of Embodiment 56, wherein the surface has a temperature in the range of 25°C to 150°C, for example, 25°C to 100°C, or 25°C to 90°C, or 25°C to 85°C, or 25°C to 80°C, or 25°C to 75°C, or 25°C to 70°C.

[0179] Embodiment 59 relates to the method according to Embodiment 56, wherein the surface has a temperature in the range of 30°C to 150°C, for example, 30°C to 100°C, or 30°C to 90°C, or 30°C to 85°C, or 30°C to 80°C, or 30°C to 75°C, or 30°C to 70°C; or 40°C to 150°C, for example, 50°C to 150°C, or 60°C to 150°C, or 70°C to 150°C, or 80°C to 150°C, or 90°C to 150°C, or 100°C to 150°C, or 110°C to 150°C.

[0180] Embodiment 60 relates to the method of Embodiment 56, wherein the surface has a temperature in the range of 50°C to 150°C, for example, 50°C to 140°C, or 50°C to 130°C, or 50°C to 120°C, or 50°C to 110°C, or 50°C to 100°C, or 50°C to 90°C, or 50°C to 80°C.

[0181] Embodiment 61 relates to the method according to any of Embodiments 56 to 60, wherein the thermal management fluid is a mass of stationary (i.e., non-circulating) fluid.

[0182] Embodiment 62 relates to a method according to any one of Embodiments 56 to 60, wherein contact is achieved by circulating a thermal management fluid over the surface.

[0183] Embodiment 63 relates to a method according to any one of Embodiments 56 to 60, wherein contact is achieved by circulating a heat management fluid between the heat exchanger and the surface.

[0184] Embodiment 64 relates to a method according to any one of Embodiments 56 to 63, wherein the heat source is an operating electrical component.

[0185] Embodiment 65 relates to the method according to any one of Embodiments 56 to 63, wherein the heat source is a battery pack, capacitor, inverter, electrical cable, fuel cell, motor, computer, or high-power charging device.

[0186] Embodiment 66 relates to the method according to any one of Embodiments 56 to 63, wherein the heat source is an electrochemical cell.

[0187] Embodiment 67 relates to the method of Embodiment 66, wherein the electrochemical cell is selected from a solid electrochemical cell, a lithium-sulfur electrochemical cell, a lithium iron phosphate electrochemical cell, a lithium-ion polymer electrochemical cell, a sodium-ion electrochemical cell, an aluminum-ion cell, a lead-acid cell, and a magnesium-ion cell.

[0188] Embodiment 68 relates to the method according to any one of embodiments 56 to 67, wherein the surface is the inner surface of a conduit that is substantially in thermal communication with a heat source.

[0189] Embodiment 69 relates to the method of Embodiment 68, wherein the conduit passes through a housing surrounding an electrical component.

[0190] Embodiment 70 relates to a battery system. Housing and One or more electrochemical cells arranged within the housing and A fluid path extending within the housing and substantially in thermal communication with one or more electrochemical cells A thermal management fluid according to any one of embodiments 1 to 55, disposed within the fluid path,

[0191] Embodiment 71 relates to the battery system of Embodiment 70, wherein the electrochemical cell is a lithium-ion electrochemical cell.

[0192] Embodiment 72 relates to the battery system of Embodiment 70, wherein the electrochemical cell is a solid electrochemical cell, a lithium-sulfur electrochemical cell, or a lithium-sulfur electrochemical cell. The cell includes lithium iron phosphate electrochemical cells, lithium ion polymer electrochemical cells, sodium ion electrochemical cells, aluminum ion cells, lead acid cells, or magnesium ion cells.

[0193] Embodiment 73 relates to an electric vehicle equipped with a battery system according to any of Embodiments 70 to 72.

[0194] Embodiment 73 is a thermal management circuit, and the thermal management circuit is Fluid paths extending around and / or through the heat source A thermal management fluid according to any one of Embodiments 1 to 55, which is disposed within the fluid path, circulates within the fluid path, and is configured to absorb thermal energy generated by the heat source, The fluid is disposed within the fluid path, the heat exchanger, the pump, and the connecting duct.

[0195] Embodiment 74 relates to a method for preparing a thermal management fluid according to any of Embodiments 1 to 55, and this method is Compound of formula (II)

[0196] [ka] m is an integer, either 1, 2, or 3; n is an integer 1, 2, 3, 4, 5, 6, 7, or 8; A method comprising reacting R3, R4, Rs, and Re independently with H and C1-C6 alkyl groups with (C6-C12 alkyl)-L (wherein L is a leaving group) to obtain a dielectric compound of formula (I).

[0197] Embodiment 75 relates to the method of Embodiment 74, wherein the contact between the compound of formula (II) and (C6-C12 alkyl)-L occurs in the presence of a catalyst.

[0198] Embodiment 76 relates to the method of Embodiment 73 or 74 and further comprises mixing a dielectric compound in an amount ranging from 1% to 99.9% by weight based on the total weight of the thermal management fluid with one or more of the following: base oil, corrosion inhibitors, antioxidants (such as phenolic and amine antioxidants), pour point depressants, defoamers, viscosity index modifiers, preservatives, biocides, surfactants, seal swelling additives, flame retardants, and combinations thereof.

[0199] Finally, it should be understood that the various embodiments described herein are illustrative of the methods of the disclosure. Other modifications that may be adopted are within the scope of the disclosure. Therefore, alternative configurations of the methods may be used, in accordance with the teachings herein, as examples rather than limitations. Thus, the methods of the disclosure are not exactly limited to those shown and described herein.

Claims

1. A thermally controlled fluid is brought into contact with a surface having a temperature of at least 25°C, and the surface is in substantially thermal communication with the heat source. A method for causing a heat-controlled fluid to absorb thermal energy from a heat source through a surface, Thermal control fluids are, It comprises one or more dielectric compounds represented by formula (I), 【Chemistry 1】 Here, m is an integer 1, n is an integer 1, 2, 3, 4, 5, 6, 7, or 8. R 1 C 6 ~C 12 It is alkyl, R 2 C 6 ~C 12 It is alkyl, R 3 and R 4 are each independently H and C 1 to C 6 selected from alkyl, R 5 and R 6 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, One or more dielectric compounds are present in a total amount ranging from 1% to 100% by weight based on the total weight of the thermally controlled fluid. The thermal control fluid is characterized by having a flash point of at least 100°C as measured according to ASTM D93, and the thermal control fluid has a dielectric constant of at least 1.5 at 25°C.

2. The method according to claim 1, wherein each of the one or more compounds has a total number of carbon atoms of 14 to 50.

3. R 1 C 6 ~C 10 It is alkyl, R 2 C 6 ~C 10 The method according to claim 1 or 2, wherein the alkyl group is used.

4. R 2 Branches and / or R 2 R 2 The method according to any one of claims 1 to 3, wherein the oxygen atom to which the bond is located is at the β position.

5. R 3 , R 4 , R 5 , and R 6 Each of them is H, that is, the compound has the following formula, 【Chemistry 2】 or R 4 , R 5 , and R 6 Each of them is H, and R 3 C 1 ~C 6 It is alkyl, that is, the compound has the following formula 【Transformation 3】 The method according to any one of claims 1 to 4.

6. One or more compounds represented by formula (I) have the following structure: 【Chemistry 4】 Here, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C 3 ~C 8 It is alkyl, One or more compounds represented by formula (I) have the following structure: 【Transformation 5】 Here, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C 3 ~C 8 It is alkyl, One or more compounds represented by formula (I) have the following structure: 【Transformation 6】 Here, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C 3 ~C 8 It is alkyl, One or more compounds represented by formula (I) have the following structure: 【Transformation 7】 Here, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C 3 ~C 8 Alkyl and / or One or more compounds represented by formula (I) have the following structure: 【Transformation 8】 Here, Ra and Rb are independently methyl or ethyl, and Rc and Rd are independently C 3 ~C 8 The method according to claim 1, wherein the alkyl group is present.

7. One or more dielectric compounds, independently, 【Chemistry 9】 The method according to claim 1, selected from among.

8. The method according to any one of claims 1 to 7, wherein one or more dielectric compounds are present in an amount ranging from 50% to 99.9% by weight.

9. The method according to any one of claims 1 to 8, wherein the thermally controlled fluid has a flash point of at least 140°C as measured according to ASTM D93.

10. The method according to any one of claims 1 to 9, wherein the thermally controlled fluid has a kinematic viscosity at 40°C measured according to ASTM D455 in the range of 1.5 to 20 cSt.

11. The method according to any one of claims 1 to 10, wherein the surface has a temperature in the range of 50°C to 150°C.

12. The method according to any one of claims 1 to 11, wherein the heat source is an operating electrical component.

13. It is a battery system, Housing and One or more electrochemical cells arranged within the housing, A fluid path extending within the housing and substantially in thermal communication with one or more electrochemical cells, A thermal management fluid is placed within the fluid path, Thermal control fluids are, It comprises one or more dielectric compounds represented by formula (I), 【Chemistry 10】 Here, m is an integer 1, n is an integer 1, 2, 3, 4, 5, 6, 7, or 8. R 1 C 6 ~C 12 It is alkyl, R 2 C 6 ~C 12 It is alkyl, R 3 and R 4 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, R 5 and R 6 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, One or more dielectric compounds are present in a total amount ranging from 1% to 100% by weight based on the total weight of the thermal management fluid. A battery system in which the thermal control fluid has a flash point of at least 100°C as measured according to ASTM D93, and the thermal control fluid has a dielectric constant of at least 1.5 at 25°C.

14. It is a thermal management circuit, A fluid path extending around and / or through the heat source, The system comprises a thermal management fluid that is placed within a fluid path, circulates within the fluid path, and is configured to absorb thermal energy generated by a heat source, The fluid is located within the fluid path, heat exchanger, pump, and connecting duct. Thermal control fluids are, It comprises one or more dielectric compounds represented by formula (I), 【Chemistry 11】 Here, m is an integer 1, n is an integer 1, 2, 3, 4, 5, 6, 7, or 8. R 1 C 6 ~C 12 It is alkyl, R 2 C 6 ~C 12 It is alkyl, R 3 and R 4 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, R 5 and R 6 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, One or more dielectric compounds are present in a total amount ranging from 1% to 100% by weight based on the total weight of the thermal management fluid. A thermal control fluid has a flash point of at least 100°C as measured according to ASTM D93, and the thermal control fluid has a dielectric constant of at least 1.5 at 25°C in a thermal control circuit.

15. A thermal management fluid for dissipating heat in a battery system, It comprises one or more dielectric compounds represented by formula (I), 【Chemistry 12】 Here, m is an integer 1, n is an integer 1, 2, 3, 4, 5, 6, 7, or 8. R 1 C 6 ~C 12 It is alkyl, R 2 C 6 ~C 12 It is alkyl, R 3 and R 4 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, R 5 and R 6 These are H and C, respectively, independently. 1 ~C 6 Selected from alkyl groups, One or more dielectric compounds are present in a total amount ranging from 1% to 100% by weight, based on the total weight of the thermally controlled fluid. The thermal control fluid is a thermal control fluid having a flash point of at least 100°C as measured according to ASTM D93, and having a dielectric constant of at least 1.5 at 25°C.

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