Immersion cooling liquid and preparation method thereof, battery device and power-using device

Abstract

This application provides an immersion coolant, a preparation method thereof, a battery device, and an electrical device. The immersion coolant comprises the following components, by weight: 40 to 50 parts of a polyalphaolefin synthetic base oil (PAO 2), 50 to 60 parts of a polyalphaolefin synthetic base oil (PAO 4), 0.1 to 0.4 parts of a pour point depressant, and 0.1 to 0.9 parts of an antioxidant. The immersion coolant exhibits excellent fluidity, stability, and heat transfer properties.

Description

Technical Field

[0001] The present application relates to the technical field of battery thermal management, and in particular to an immersion coolant and a preparation method thereof, a battery device, and an electrical device. Background Art

[0002] In recent years, as the application scope of secondary batteries has become increasingly wider, secondary batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as in many fields such as power tools, electric bicycles, electric motorcycles and electric vehicles.

[0003] Secondary batteries generate a large amount of heat during the charging and discharging process. For example, the temperature of electric vehicle batteries can rise rapidly during rapid charging or high-load discharge. By setting up a battery thermal management device, the coolant in the thermal management device can absorb the large amount of heat generated by the battery and transfer the heat through the circulation system, thereby effectively controlling the battery temperature. By circulating the coolant in the battery pack, the temperature uniformity of various parts of the battery can also be improved, alleviating local overheating or overcooling in the battery pack, better protecting the battery and extending the battery life.

[0004] Immersion cooling technology is a battery thermal management method that directly immerses batteries in a coolant. It offers advantages such as simple structure, rapid cooling, and excellent temperature uniformity. It effectively reduces battery temperature and improves temperature uniformity across the battery pack. The coolant used in this technology, also known as immersion coolant, must meet certain selection criteria, including good electrical insulation, non-flammability, an appropriate operating temperature range, a long service life, good material compatibility, low mass, low viscosity, and low corrosiveness.

[0005] With the increasing application of secondary batteries, higher performance requirements are being placed on the immersion coolants used in battery thermal management systems. Conventional immersion coolants still require further improvement in terms of fluidity, stability, and heat transfer performance. Therefore, developing an immersion coolant with superior fluidity, stability, and heat transfer performance has become a key research direction in this field. Summary of the Invention

[0006] This application is made in view of the above-mentioned problems, and one of its purposes is to provide an immersion coolant and a preparation method thereof, a battery device and an electrical device, wherein the immersion coolant has good fluidity, stability and heat transfer performance.

[0007] In order to achieve the above-mentioned object, the first aspect of the present application provides an immersion cooling liquid comprising the following components in parts by weight:

[0008] 40 to 50 parts of polyalphaolefin synthetic base oil PAO 2, 50 to 60 parts of polyalphaolefin synthetic base oil PAO 4, 0.1 to 0.4 parts of pour point depressant and 0.1 to 0.9 parts of antioxidant.

[0009] By combining polyalphaolefin (PAO) synthetic base oils (PAO 2) and (PAO 4) as the base oils for the immersion coolant, and compounding them with a pour point depressant and antioxidant, the immersion coolant exhibits excellent fluidity, stability, and heat transfer performance through the coordinated use of these components at specific dosages. PAO 2 and PAO 4, both polyalphaolefin (PAO) synthetic base oils, offer superior stability compared to ester base oils. Furthermore, PAO 2's low viscosity and excellent fluidity allow it to flow rapidly within the battery pack during low-temperature operation, rapidly dissipating heat generated by the cells. PAO 4, on the other hand, has a relatively high viscosity, maintaining stable heat transfer efficiency during high-temperature operation, ensuring the coolant maintains excellent thermal conductivity even at higher temperatures. The addition of a specific amount of antioxidant further enhances the stability of PAO 2 and PAO 4, thereby improving the stability of the immersion coolant. The addition of a specific amount of pour point depressant lowers the pour point of the immersion coolant, enabling it to maintain excellent fluidity even at lower temperatures. By compounding PAO 2, PAO 4, pour point depressant and antioxidant in specific proportions, the coolant can have better fluidity, stability and heat transfer performance, and can better adapt to battery operating conditions at different temperatures.

[0010] In any embodiment, the composition includes the following components, by weight: 45 to 49 parts of polyalphaolefin synthetic base oil PAO 2, 50 to 54 parts of polyalphaolefin synthetic base oil PAO 4, 0.1 to 0.4 parts of pour point depressant, and 0.1 to 0.9 parts of antioxidant. This further improves the fluidity and heat transfer performance of the immersion coolant.

[0011] In any embodiment, the kinematic viscosity of the polyalphaolefin synthetic base oil PAO 2 at 100°C is 1 mm 2 / s~3mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 2 is greater than or equal to 90. This is conducive to enabling the immersion coolant to adapt to a wider temperature range.

[0012] In any embodiment, the kinematic viscosity of the polyalphaolefin synthetic base oil PAO 4 at 100° C. is 3.6 mm 2 / s~4.9mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 4 is greater than or equal to 120. This is conducive to enabling the immersion coolant to adapt to a wider temperature range.

[0013] In any embodiment, the antioxidant comprises one or more of a hindered phenol antioxidant and an ester antioxidant. Thus, the use of the above-mentioned antioxidants is beneficial to improving the stability of the immersion cooling liquid.

[0014] In any embodiment, the hindered phenolic antioxidant includes one or more of Irganox L107, 2,6-di-tert-butyl-p-cresol, Irganox L39, and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate. Using the above-mentioned types of antioxidants as hindered phenolic antioxidants can achieve good antioxidant effects.

[0015] In any embodiment, the ester antioxidant includes one or more of dilauryl thiodipropionate, distearyl thiodipropionate, triphenyl phosphite, tris(nonylphenyl) phosphite, and pentaerythritol tetrakis(3-dodecyloxythiopropionate). Using the above-mentioned antioxidants as the ester antioxidant can achieve a good antioxidant effect.

[0016] In any embodiment, the antioxidant comprises a hindered phenolic antioxidant and an ester antioxidant, with the weight ratio of the hindered phenolic antioxidant to the ester antioxidant being 3 to 8:2. By combining the two types of antioxidants in a specific ratio, the oxidation reaction process can be blocked at different stages, thereby synergistically improving the antioxidant performance and stability of the immersion coolant.

[0017] In any embodiment, the pour point depressant includes one or more polymethacrylate-type pour point depressants and their modifications. The use of the above-mentioned pour point depressants is beneficial for lowering the pour point of the immersion coolant and improving the low-temperature fluidity of the immersion coolant.

[0018] Without limitation, the modified polymethacrylate type pour point depressants include long-chain alkyl modified polymethacrylate pour point depressants, polar group-containing modified polymethacrylate pour point depressants, copolymerized modified polymethacrylate pour point depressants, high molecular weight modified polymethacrylate pour point depressants, and the like.

[0019] In any embodiment, 0.05 to 0.3 parts by weight of a defoaming agent is also included, which helps to reduce the amount of bubbles formed during use of the coolant, thereby alleviating the corrosion effect on the surface metal.

[0020] In any embodiment, the defoaming agent includes one or more of a nonionic surfactant, an aliphatic defoaming agent, and an aromatic hydrocarbon defoaming agent. In this way, the amount of bubbles formed in the coolant during use can be effectively reduced, thereby alleviating corrosion to the surface metal.

[0021] A second aspect of the present application provides a method for preparing an immersion cooling liquid, comprising the following steps:

[0022] Providing raw materials according to the composition of the immersion cooling liquid of the first aspect of the present application;

[0023] The raw materials are stirred and mixed uniformly to obtain the immersion cooling liquid.

[0024] Thus, the preparation method has simple process and low production cost.

[0025] In any embodiment, the stirring and mixing temperature is 45° C. to 65° C., the stirring and mixing speed is 1000 r / min to 2000 r / min, and the stirring and mixing time is 2 h to 3 h. This is conducive to forming an immersion coolant with uniform composition and stable performance.

[0026] In any embodiment, after the raw materials are stirred and mixed uniformly, the process further includes the steps of allowing the mixture to stand and cool for 2 to 3 hours and then filtering to obtain the filtrate.

[0027] A third aspect of the present application provides a battery device comprising a housing, battery cells, and the immersion coolant of the first aspect of the present application, wherein the battery cells and the immersion coolant are housed in the housing, and the battery cells are at least partially immersed in the immersion coolant.

[0028] A fourth aspect of the present application provides an electrical device comprising the battery device of the third aspect of the present application. DETAILED DESCRIPTION

[0029] The following describes in detail the embodiments of the immersion coolant and its preparation method, battery device, and electrical device of the present application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary length in the following description and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0030] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and any end value can be independently included or excluded, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also contemplated. In addition, if the minimum range values ​​listed are 1 and 2, and if the maximum range values ​​3, 4, and 5 are also listed, the following ranges can all be contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0031] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0032] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0033] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0034] It will be appreciated by those skilled in the art that, in the methods of various embodiments or examples, the order in which the steps are written does not imply a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible inherent logic. Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0035] In this application, open technical features or technical solutions described with words such as "contain," "include," and "include" do not exclude additional members beyond the listed members, unless otherwise specified. This can be considered as providing both closed features or solutions consisting of the listed members and open features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may or may not include other members unless otherwise specified. This can be considered as providing both the feature or solution that "A consists of a1, a2, and a3," and the feature or solution that "A includes not only a1, a2, and a3, but also other members." In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0036] In this application, the terms "optionally," "optional," and "optional" are optional and refer to either option being present or absent. If a technical solution contains multiple "options," each option is considered independent unless otherwise specified and there are no conflicts or constraints.

[0037] With the increasing application of secondary batteries, higher performance requirements are being placed on the immersion coolant used in battery thermal management devices. Conventional immersion coolants still require further improvement in terms of fluidity, stability, and heat transfer performance. To address this issue, the present application provides an immersion coolant with excellent fluidity, stability, and heat transfer performance, effectively meeting the performance requirements of battery thermal management devices.

[0038] In one embodiment of the present application, an immersion coolant is provided, which comprises the following components, by weight: 40 to 50 parts of polyalphaolefin synthetic base oil PAO 2, 50 to 60 parts of polyalphaolefin synthetic base oil PAO 4, 0.1 to 0.4 parts of pour point depressant, and 0.1 to 0.9 parts of antioxidant.

[0039] The immersion coolant described above in this application uses 40 to 50 parts of polyalphaolefin synthetic base oil PAO 2 and 50 to 60 parts of polyalphaolefin synthetic base oil PAO 4 as the base oil of the immersion coolant, and is compounded with 0.1 to 0.4 parts of pour point depressant and 0.1 to 0.9 parts of antioxidant. Through the mutual cooperation between the components, the immersion coolant has good fluidity, good stability and heat transfer performance. Specifically, PAO 2 and PAO 4 are both polyalphaolefin synthetic base oils, which have better stability than ester base oils; and PAO 2 has low viscosity and good fluidity. When the battery is running at low temperature, it can flow quickly inside the battery pack and quickly take away the heat generated by the battery; while PAO 4 has a relatively high viscosity and can maintain stable heat transfer efficiency under high-temperature operating conditions of the battery, ensuring that the coolant can still maintain good thermal conductivity at higher temperatures. The addition of a specific amount of antioxidant further improves the stability of PAO 2 and PAO 4, thereby enhancing the stability of the immersion coolant. The addition of a specific amount of pour point depressant helps lower the pour point of the immersion coolant, allowing it to maintain good fluidity at lower temperatures. By combining PAO 2, PAO 4, pour point depressant, and antioxidant in specific proportions, the coolant can exhibit improved fluidity, stability, and heat transfer properties, enabling it to better adapt to battery operating conditions at different temperatures.

[0040] In addition, compared with traditional fluorinated liquid immersion coolants, the immersion coolant of the present application has lower cost, is less difficult to recycle and reuse, has less pollution to the environment, has a simpler preparation process, and has a higher cost-effectiveness.

[0041] It should be noted that PAO 2 is a specific brand of polyalphaolefin synthetic base oil. The "PAO" in PAO 2 stands for polyalphaolefin, and the "2" represents that the center value of the kinematic viscosity of the base oil at 40°C is about 2mm. 2 / s. Similarly, polyalphaolefin synthetic base oil PAO 4 is a specific grade of polyalphaolefin synthetic base oil. The "4" in PAO4 represents that the central value of the kinematic viscosity of the base oil at 40°C is about 4mm 2 / s.

[0042] It can be understood that the amount of polyalphaolefin synthetic base oil PAO 2 in the immersion coolant can be 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, and any value within the range formed by any two of the above values; the amount of polyalphaolefin synthetic base oil PAO 4 can be 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, and any value within the range formed by any two of the above values; the amount of antioxidant can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, and any value within the range formed by any two of the above values. The amount of the pour point depressant can be 0.1 part, 0.125 part, 0.15 part, 0.175 part, 0.2 part, 0.225 part, 0.25 part, 0.275 part, 0.3 part, 0.325 part, 0.35 part, 0.375 part, 0.4 part and any value within the range formed by any two of the above values.

[0043] In some embodiments, the total weight of the polyalphaolefin synthetic base oil PAO 2, the polyalphaolefin synthetic base oil PAO 4, the pour point depressant, and the antioxidant in the immersion coolant is 100 parts.

[0044] In some embodiments, the immersion coolant comprises the following components, by weight: 45-49 parts of a polyalphaolefin synthetic base oil (PAO 2), 50-54 parts of a polyalphaolefin synthetic base oil (PAO 4), 0.1-0.4 parts of a pour point depressant, and 0.1-0.9 parts of an antioxidant. By compounding the polyalphaolefin synthetic base oil (PAO 2), the polyalphaolefin synthetic base oil (PAO 4), and the antioxidant in the aforementioned weight ratios, the immersion coolant exhibits improved fluidity and heat transfer properties.

[0045] In some embodiments, the kinematic viscosity of the polyalphaolefin synthetic base oil PAO 2 at 100°C is 1 mm 2 / s~3mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 2 is greater than or equal to 90, and optionally, the viscosity index is greater than or equal to 120. Thus, the polyalphaolefin synthetic base oil PAO 2 has a low kinematic viscosity and can still maintain good fluidity in low-temperature environments; the polyalphaolefin synthetic base oil PAO 2 has a large viscosity index and excellent viscosity-temperature performance, enabling the immersion coolant to adapt to a wide temperature range.

[0046] It should be noted that kinematic viscosity refers to the time it takes for a certain volume of liquid to flow through a calibrated glass capillary viscometer under the influence of gravity at a constant temperature. Kinematic viscosity is an important indicator of liquid fluidity, reflecting the internal friction generated by the relative motion of base oil molecules under the influence of gravity. The viscosity index is a conventional value that indicates the temperature-dependent viscosity behavior of a base oil. Generally, a higher viscosity index indicates a lower temperature-dependent viscosity change, meaning a more stable viscosity at different temperatures.

[0047] It is understood that the kinematic viscosity of polyalphaolefin synthetic base oil PAO 2 at 100°C can be 1 mm 2 / s、1.1mm 2 / s、1.2mm 2 / s、1.3mm 2 / s、1.4mm 2 / s、1.5mm 2 / s、1.6mm 2 / s、1.7mm 2 / s、1.8mm 2 / s、1.9mm 2 / s, 2.0mm 2 / s, 2.1mm 2 / s、2.2mm 2 / s, 2.3mm 2 / s、2.4mm 2 / s、2.5mm 2 / s、2.6mm 2 / s, 2.7mm 2 / s、2.8mm 2 / s, 2.9mm 2 / s、3mm 2 / s and any value within the range formed by any two of the above values.

[0048] In some embodiments, the kinematic viscosity of the polyalphaolefin synthetic base oil PAO 4 at 100°C is 3.6 mm 2 / s~4.9mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 4 is greater than or equal to 120, and optionally, greater than or equal to 130. Thus, the polyalphaolefin synthetic base oil PAO 4 has a higher kinematic viscosity than the polyalphaolefin synthetic base oil PAO 2. Compounding it with the polyalphaolefin synthetic base oil PAO 2 can improve the high-temperature performance and stability of the immersion coolant. The higher viscosity index of the polyalphaolefin synthetic base oil PAO 4 helps prevent the immersion coolant's viscosity from increasing excessively at low temperatures, maintaining good fluidity. Furthermore, its viscosity does not drop significantly with increasing temperature, which helps the immersion coolant have a wider operating temperature range.

[0049] It is understood that the kinematic viscosity of polyalphaolefin synthetic base oil PAO 4 at 100°C can be 3.6 mm 2 / s、3.7mm 2 / s、3.8mm 2 / s、3.9mm 2 / s、4.0mm 2 / s、4.1mm 2 / s、4.2mm 2 / s、4.3mm 2 / s、4.4mm 2 / s、4.5mm 2 / s、4.6mm 2 / s、4.7mm 2 / s、4.8mm 2 / s、4.9mm 2 / s and any value within the range formed by any two of the above values.

[0050] In some embodiments, the antioxidant includes a hindered phenolic antioxidant and an ester antioxidant. Thus, by compounding the hindered phenolic antioxidant and the ester antioxidant to form a composite antioxidant, the hindered phenolic antioxidant primarily exerts its antioxidant effect by capturing free radicals and interrupting chain reactions, while the ester antioxidant primarily exerts its antioxidant effect by decomposing peroxides and preventing them from further initiating free radicals. By compounding the two, the oxidation reaction process can be blocked at different stages, thereby synergistically improving the antioxidant performance and stability of the immersion coolant.

[0051] In addition, hindered phenol antioxidants have better antioxidant effects at high temperatures, while ester antioxidants can show better antioxidant effects at medium and low temperatures. When combined, the two can provide effective antioxidant properties across different temperature ranges, thereby facilitating the use of immersion coolants in a wide temperature range.

[0052] In some embodiments, the hindered phenol antioxidant includes one or more of Irganox L107, 2,6-di-tert-butyl-p-cresol (i.e., hindered phenol T 501), Irganox L39, and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate. Using these antioxidants as hindered phenol antioxidants can achieve excellent antioxidant effects. Irganox L107 is an antioxidant product codenamed Irganox L107 produced by BASF, Germany; Irganox L39 is an antioxidant product codenamed Irganox L39 produced by BASF, Germany.

[0053] In some embodiments, the ester antioxidant includes one or more of dilauryl thiodipropionate, distearyl thiodipropionate, triphenyl phosphite, tris(nonylphenyl) phosphite, and pentaerythritol tetrakis(3-dodecyloxythiopropionate).

[0054] In some embodiments, the weight ratio of the hindered phenolic antioxidant to the ester antioxidant is 3 to 8:2. In the composite antioxidant, the hindered phenolic antioxidant serves as the primary antioxidant, the ester antioxidant serves as the secondary antioxidant, and the hindered phenolic antioxidant and the ester antioxidant are compounded in the aforementioned weight ratio, which is more conducive to improving the antioxidant performance and stability of the immersion coolant.

[0055] It is understood that the weight ratio of hindered phenol antioxidant to ester antioxidant in the composite antioxidant can be 3:2, 3.5:2, 4:2, 4.5:2, 5:2, 5.5:2, 6:2, 6.5:2, 7:2, 7.5:2, 8:2 and any ratio within the range formed by any two of the above ratios.

[0056] In some specific examples, the pour point depressant includes one or more of a polymethacrylate type pour point depressant and a modified polymethacrylate type pour point depressant. The use of the above-mentioned pour point depressants is beneficial for lowering the pour point of the immersion coolant and improving the low-temperature fluidity of the immersion coolant.

[0057] Among them, modified polymethacrylate-based pour point depressants are obtained by adjusting the structure of polymethacrylate or introducing other functional groups to further optimize its pour point depressing performance. Specifically, the introduced modified functional groups include one or more of long-chain alkyl groups, branched alcohols, hydroxyl groups, carboxyl groups, and amino groups.

[0058] In some embodiments, the immersion coolant further includes 0.05 to 0.3 parts of a defoaming agent by weight. The immersion coolant usually needs to circulate during use to improve the cooling effect. During the circulation process, the immersion coolant may generate a large number of bubbles, which will form cavitation, causing the battery thermal management device or the surface metal of the battery in contact with the immersion coolant to become embrittled, resulting in metal corrosion. By adding the above-mentioned specific amount of defoaming agent and compounding it with other components to the immersion coolant, it is beneficial to reduce the amount of bubbles formed in the coolant during use, thereby alleviating the corrosive effect on the surface metal.

[0059] In some embodiments, the total weight of the polyalphaolefin synthetic base oil PAO 2, the polyalphaolefin synthetic base oil PAO 4, the antioxidant, the pour point depressant, and the defoaming agent in the immersion coolant is 100 parts.

[0060] In some embodiments, the defoaming agent includes one or more of a nonionic surfactant, an aliphatic defoaming agent, and an aromatic hydrocarbon defoaming agent. By using the above defoaming agents, the amount of bubbles formed in the coolant during use can be effectively reduced, thereby alleviating corrosion to the surface metal.

[0061] Among them, non-ionic surfactants can be polyether non-ionic surfactants, fatty acid polyoxyethylene ester non-ionic surfactants and alkyl alcohol amide non-ionic surfactants. Aliphatic defoamers are mainly composed of aliphatic compounds, and the carbon chain in their molecular structure is a straight or branched saturated or unsaturated aliphatic hydrocarbon. Specifically, aliphatic defoamers can be stearic acid, lauryl alcohol, etc. Aromatic hydrocarbon defoamers are mainly composed of compounds containing aromatic ring structures, and their molecules usually contain one or more aromatic structures such as benzene rings. Specifically, aromatic hydrocarbon defoamers can be alkylbenzene sulfonates, phenyl silicone oil, etc.

[0062] One embodiment of the present application provides a method for preparing the above-mentioned immersion coolant, which comprises the following steps: providing raw materials according to the components of the above-mentioned immersion coolant; and stirring and mixing the raw materials to obtain the immersion coolant.

[0063] In some embodiments, the stirring temperature is 45°C to 65°C, the stirring speed is 1000 r / min to 2000 r / min, and the stirring time is 2 hours to 3 hours. Under these stirring temperature, stirring speed, and stirring time conditions, the raw material components of the immersion coolant are sufficiently mixed to form an immersion coolant with uniform composition and stable performance.

[0064] It can be understood that the temperature of the stirring and mixing can be 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C and any value within the range formed by any two of the above values; the stirring speed of the stirring and mixing can be 1000r / min, 1100r / min, 1200r / min, 1300r / min, 1400r / min, 1500r / min, 1600r / min, 1700r / min, 1800r / min, 1900r / min, 2000r / min and any value within the range formed by any two of the above values; the stirring and mixing time can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h, 3h and any value within the range formed by any two of the above values.

[0065] In some embodiments, after the raw materials are stirred and mixed uniformly, the mixture is allowed to cool for 2-3 hours and then filtered. By allowing the stirred and mixed raw materials to cool for 2-3 hours before filtering, some solid impurities in the immersion coolant can be removed, further improving the uniformity of the immersion coolant. It is understood that the cooling time can be 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours, 3 hours, or any value within the range formed by any two of the above values.

[0066] The immersion coolant of this application can be used as a coolant material in battery thermal management devices. Furthermore, this immersion coolant can also be applied to other fields requiring cooling and heat dissipation to extend the life of equipment. For example, it can be used in cooling systems for data center servers, high-performance computers, avionics equipment, and medical imaging equipment.

[0067] In one embodiment of the present application, a battery device is provided, which includes a box, battery cells, and the immersion coolant described above. The battery cells and the immersion coolant are accommodated in the box, and the battery cells are at least partially immersed in the immersion coolant.

[0068] The immersion coolant in the battery assembly is used to immerse and cool the battery cells, thereby protecting them and extending their service life. Specifically, the battery cells can be partially or fully immersed in the immersion coolant. The battery assembly is primarily designed to ensure that the battery cells remain within the optimal operating temperature range under various operating conditions and environmental conditions, thereby improving battery performance, extending service life, and ensuring safety.

[0069] Furthermore, the battery device may also include a thermal management fluid circuit, a heating system, a temperature detection and control system, etc. Among them, the thermal management fluid circuit includes a coolant, a pipe and a radiator. The coolant is used to cool down the battery cells. The immersion coolant usually comes into direct contact with the battery cells to dissipate heat; the pipe is responsible for the circulation of the coolant in the battery pack; the radiator is used to dissipate the heat in the coolant to the external environment. The heating system usually includes a heater, which is used to heat the coolant or directly heat the battery pack to increase the battery temperature when the battery temperature is too low. The temperature detection and control system usually includes a temperature sensor and a control unit. The temperature sensor is used to monitor the battery temperature in real time and feed back the temperature information to the control unit; the control unit receives the battery temperature signal from the temperature sensor and adjusts the heating system or cooling equipment according to the preset temperature range to manage the battery temperature.

[0070] In one embodiment of the present application, an electric device is provided, comprising the battery device described above. As a non-limiting example, the electric device may be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like.

[0071] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0072] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0073] Example 1:

[0074] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of dilauryl thiodipropionate antioxidant, 0.2g of modified polymethacrylate pour point depressant (TC-256P), and 0.2g of Synative AC AMH 2 defoamer. The kinematic viscosity of PAO 2 at 100°C is 2.3mm. 2 / s, viscosity index is 124; the kinematic viscosity of PAO 4 at 100℃ is 3.93mm2 / s, viscosity index is 132.

[0075] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0076] Example 2:

[0077] Prepare 45g of polyalphaolefin synthetic base oil PAO 2, 54g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0078] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0079] Example 3:

[0080] Prepare 47g of polyalphaolefin synthetic base oil PAO 2, 52g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0081] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0082] Example 4:

[0083] Prepare 49g of polyalphaolefin synthetic base oil PAO 2, 50g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0084] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0085] Example 5:

[0086] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.42g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.28g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0087] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0088] Example 6:

[0089] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.56g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.14g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0090] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0091] Example 7:

[0092] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.06g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.04g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0093] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0094] Example 8:

[0095] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.7g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0096] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0097] Example 9:

[0098] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.4g of modified polymethacrylate type pour point depressant (TC-256P) and 0.2g of Synative AC AMH 2 defoaming agent respectively.

[0099] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0100] Example 10:

[0101] Prepare 42g of polyalphaolefin synthetic base oil PAO 2, 57g of polyalphaolefin synthetic base oil PAO 4, 0.5g of 2,6-di-tert-butyl-p-cresol antioxidant (hindered phenol T 501), 0.2g of Irganox L107 antioxidant, 0.2g of modified polymethacrylate type pour point depressant (TC-256P) and 0.05g of Synative AC AMH 2 defoaming agent respectively.

[0102] The polyalphaolefin synthetic base oil PAO 2 and the polyalphaolefin synthetic base oil PAO 4 were mixed, and the 2,6-di-tert-butyl-p-cresol antioxidant, Irganox L107 antioxidant, TC-256P pour point depressant, and Synative AC AMH 2 defoaming agent were added to the mixed base oil under stirring at 45° C. and 1000 r / min. The mixture was then stirred for 2 hours, allowed to stand for 2 hours, and then filtered and packaged to obtain an immersion coolant.

[0103] Comparative Example 1:

[0104] This comparative example is basically the same as Example 1, except that: Esterex A 32 base oil produced by Lubrizol Corporation of the United States is used instead of polyalphaolefin synthetic base oil PAO 2, and Esterex A 41 base oil produced by ExxonMobil Corporation of the same quality is used instead of polyalphaolefin synthetic base oil PAO 4. The kinematic viscosity of Esterex A 32 at 100°C is 6.6 mm 2 / s, viscosity index is 168; Esterex A 41 has a kinematic viscosity of 8.3 mm at 100°C. 2 / s, viscosity index is 149.

[0105] Comparative Example 2:

[0106] This comparative example is basically the same as Example 1, except that the same mass of polyalphaolefin synthetic base oil PAO6 is used instead of polyalphaolefin synthetic base oil PAO 2. The kinematic viscosity of PAO 6 at 100°C is 5.76 mm 2 / s, viscosity index is 134.

[0107] Comparative Example 3:

[0108] This comparative example is basically the same as Example 1, except that the amount of poly-α-olefin synthetic base oil PAO 2 is reduced to 30 g.

[0109] Comparative Example 4:

[0110] This comparative example is substantially the same as Example 1, except that the amount of the poly-α-olefin synthetic base oil PAO 4 is reduced to 40 g.

[0111] Test method:

[0112] The properties of the immersion coolants and their raw materials in the above examples and comparative examples were tested. These tests primarily included testing the base oil's kinematic viscosity at 100°C, base oil viscosity index, coolant specific heat capacity, coolant antioxidant capacity, coolant breakdown voltage, coolant volume conductivity, coolant viscosity at 100°C, and coolant pour point.

[0113] in:

[0114] Base oil 100℃ kinematic viscosity test: Refer to GB / T 265 standard and test the kinematic viscosity of the base oil at 100℃.

[0115] Base oil viscosity index test: According to GB / T 265, the kinematic viscosity of the base oil is tested at 40°C and 100°C respectively, and the viscosity index of the base oil is calculated according to GB / T 1995.

[0116] Coolant specific heat capacity test: Refer to ASTM D7896-19 test method to test the specific heat capacity of the coolant at 50°C.

[0117] Coolant thermal conductivity test: Refer to ASTM D7896-19 test method to test the thermal conductivity of the coolant at 50°C.

[0118] Coolant antioxidant capacity test: The rotating oxygen bomb method is used to test the coolant's antioxidant capacity at 150°C.

[0119] Coolant breakdown voltage test: Refer to GB / T 507-2002 test method to test the coolant breakdown voltage.

[0120] Coolant volume conductivity test: Refer to the "YDT_3982-2021 Technical Requirements and Test Methods for Cooling Liquids in Data Center Liquid Cooling Systems" standard and use the GB / T 5654-2007 method to test the volume conductivity of the coolant at 20°C.

[0121] Coolant viscosity test at 100°C: Same as the base oil kinematic viscosity test method at 100°C.

[0122] Coolant pour point test: Refer to GB / T 3535-2006 standard and use a pour point tester to test the pour point of the coolant under low temperature conditions.

[0123] The parameters of the immersion cooling liquids of the embodiments and comparative examples are shown in Table 1:

[0124] Table 1

[0125]

[0126] The performance data of the immersion cooling liquids of the embodiments and comparative examples are shown in Table 2:

[0127] Table 2

[0128]

[0129] As shown in Tables 1 and 2, the immersion coolant of each embodiment of the present application has a low pour point, low viscosity at 100°C, and an appropriate viscosity index, resulting in good fluidity. It also has suitable volume conductivity, a high breakdown voltage, good thermal and electrochemical stability, and good oxidation resistance. Furthermore, it has a high specific heat capacity and thermal conductivity, resulting in good heat transfer performance. The immersion coolant of the present application exhibits excellent fluidity, stability, and heat transfer performance, effectively meeting the performance requirements of a battery thermal management device for a coolant.

[0130] Comparative Example 1, compared with Example 1, uses Esterex A 32 base oil and Esterex A 41 base oil instead of the poly-α-olefin synthetic base oil PAO 2 and poly-α-olefin synthetic base oil PAO 4, respectively. The coolant in Comparative Example 1 exhibits an increased pour point, high viscosity at 100°C, and high viscosity index, resulting in poor flow and low-temperature performance. The coolant also exhibits a significantly decreased specific heat capacity and reduced thermal conductivity, resulting in poor heat transfer performance. The coolant also exhibits a low breakdown voltage and poor electrochemical stability.

[0131] Comparative Example 2, compared with Example 1, uses poly-α-olefin synthetic base oil PAO 6 instead of poly-α-olefin synthetic base oil PAO 2. The coolant in Comparative Example 2 has higher viscosity and viscosity index at 100°C, indicating poor flow properties. Furthermore, the coolant in Comparative Example 2 has lower specific heat capacity and thermal conductivity, indicating poor heat transfer performance.

[0132] Compared with Example 1, Comparative Example 3 used too little polyalphaolefin synthetic base oil PAO 2, resulting in a coolant with a low breakdown voltage, poor electrochemical stability, and reduced antioxidant properties. Compared with Example 1, Comparative Example 4 used too little polyalphaolefin synthetic base oil PAO 4, resulting in a coolant with low specific heat capacity and thermal conductivity, resulting in reduced heat transfer performance. The coolant also had a low viscosity index, a greater temperature-dependent viscosity change, decreased low-temperature fluidity, and reduced heat dissipation efficiency at high temperatures. Furthermore, the coolant's antioxidant properties were reduced.

[0133] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0134] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An immersion coolant, characterized in that: The components are as follows in parts by weight: 45 to 49 parts of polyalphaolefin synthetic base oil PAO 2, 50 to 54 parts of polyalphaolefin synthetic base oil PAO 4, 0.1 to 0.4 parts of pour point depressant, 0.05 to 0.3 parts of defoaming agent and 0.1 to 0.9 parts of antioxidant; The pour point depressant includes one or more polymethacrylate pour point depressants and modified products thereof; the antioxidant includes one or more hindered phenol antioxidants and ester antioxidants.

2. The immersion cooling liquid according to claim 1, characterized in that The kinematic viscosity of the polyalphaolefin synthetic base oil PAO 2 at 100°C is 1 mm 2 / s~3mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 2 is greater than or equal to 90.

3. The immersion cooling liquid according to claim 1, characterized in that The kinematic viscosity of the polyalphaolefin synthetic base oil PAO 4 at 100°C is 3.6 mm 2 / s~4.9mm 2 / s, and the viscosity index of the polyalphaolefin synthetic base oil PAO 4 is greater than or equal to 120.

4. The immersion cooling liquid according to claim 1, characterized in that The hindered phenol antioxidant includes one or more of Irganox L107, 2,6-di-tert-butyl-p-cresol, Irganox L39 and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

5. The immersion cooling liquid according to claim 1, characterized in that The ester antioxidant includes one or more of dilauryl thiodipropionate, distearyl thiodipropionate, triphenyl phosphite, tris(nonylphenyl) phosphite and pentaerythritol tetrakis(3-dodecyloxythiopropionate).

6. The immersion cooling liquid according to claim 1, characterized in that The antioxidant comprises a hindered phenol antioxidant and an ester antioxidant, and the weight ratio of the hindered phenol antioxidant to the ester antioxidant is 3-8:

2.

7. The immersion cooling liquid according to claim 1, characterized in that The defoaming agent includes one or more of a nonionic surfactant, an aliphatic defoaming agent and an aromatic hydrocarbon defoaming agent.

8. A method for preparing an immersion cooling liquid, characterized in that: The steps include: Providing raw materials according to the components of the immersion cooling liquid according to any one of claims 1 to 7; The raw materials are stirred and mixed uniformly to obtain the immersion cooling liquid.

9. The method for preparing the immersion cooling liquid according to claim 8, characterized in that: The stirring and mixing temperature is 45° C. to 65° C., the stirring and mixing speed is 1000 r / min to 2000 r / min, and the stirring and mixing time is 2 h to 3 h.

10. The method for preparing the immersion cooling liquid according to claim 8 or 9, characterized in that: After the raw materials are stirred and mixed evenly, the method further includes the steps of allowing the mixed solution to stand and cool for 2 to 3 hours and then filtering to obtain the filtrate.

11. A battery device, characterized in that: The invention comprises a box, a battery cell and the immersion cooling liquid according to any one of claims 1 to 7, wherein the battery cell and the immersion cooling liquid are accommodated in the box, and the battery cell is at least partially immersed in the immersion cooling liquid.

12. An electrical device, characterized in that: A battery device comprising the battery device of claim 11.

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