Single-phase immersed cooling liquid as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of cooling liquid, and particularly relates to single-phase immersed cooling liquid as well as a preparation method and application thereof. The single-phase immersed cooling liquid comprises the following components in parts by mass: 45-90 parts of synthetic ester oil; 10 to 55 parts of vegetable oil; 0.2 to 1 part of an antioxidant; 0.01 to 0.05 part of a metal deactivator; wherein the vegetable oil comprises at least one of soybean oil and rapeseed oil; the vegetable oil comprises the following technical parameters: the acid value is 0.01-0.03 mgKOH / g; the dielectric loss factor is 0.01 to 0.03; the water content is 70 to 90 mg / kg. A certain proportion of vegetable oil is added into the synthetic ester oil for compounding, and tests show that the heat conductivity coefficient and lightning impulse breakdown voltage of the cooling liquid can be improved, and the gassing tendency can be improved, so that the cooling liquid does not generate gas in the storage or use process, and the safety of the cooling liquid is improved.

Description

Technical Field

[0001] This invention belongs to the field of coolant technology, specifically relating to a single-phase immersion coolant, its preparation method, and its application. Background Technology

[0002] The base oils for single-phase submerged coolants typically include naphthenic oils, PAO oils, GTL oils, and synthetic ester oils. Naphthenic oils, PAO oils, and GTL oils suffer from low flash points and are not biodegradable, posing a risk of environmental pollution should leaks occur. In contrast, synthetic ester oils have higher flash points and some biodegradability, making them more suitable for applications with high safety and biodegradability requirements.

[0003] However, synthetic ester oils have low thermal conductivity, making them unsuitable for the rapid cooling requirements of high-power equipment. Furthermore, synthetic ester oils have low lightning impulse breakdown voltage and release gases during use, leading to the accumulation of flammable gases and posing a safety hazard. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of insufficient thermal conductivity and safety of synthetic ester-based oil-immersed coolants, and to provide a single-phase immersed coolant, its preparation method and application, which can improve the thermal conductivity of ester-based oil-immersed coolants, while also improving lightning impulse breakdown voltage, reducing gas evolution tendency, and providing high safety.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] In a first aspect, the present invention provides a single-phase immersion coolant (hereinafter referred to as coolant), comprising the following components by mass:

[0007] 45-90 parts of synthetic ester oil;

[0008] 10-55 parts vegetable oil;

[0009] Antioxidant 0.2 to 1 part;

[0010] Metal deactivating agent 0.01–0.05 parts;

[0011] Vegetable oils include at least one of soybean oil and rapeseed oil;

[0012] Vegetable oils include the following technical parameters:

[0013] Acid value: 0.01–0.03 mg KOH / g;

[0014] The dielectric loss factor is 0.01 to 0.03.

[0015] Moisture content: 70–90 mg / kg.

[0016] This invention involves compounding synthetic ester oils with a certain proportion of vegetable oils possessing low acid value, low dielectric loss factor, and low moisture content. Testing has shown that this compounding improves the thermal conductivity and lightning impulse breakdown voltage of the coolant, as well as reduces the tendency for gas evolution, preventing gas generation during storage or use and thus enhancing coolant safety. The underlying mechanism may be as follows: vegetable oils such as soybean oil and rapeseed oil contain a large number of polar ester groups and double bonds, resulting in stronger intermolecular forces, higher heat transfer efficiency, and higher thermal conductivity, thereby improving the coolant's thermal conductivity. Furthermore, the double bonds (C=C) on the fatty acid chains in vegetable oils can absorb high-energy electrons, forming highly stable anionic free radicals that block ionization channel formation and withstand high-voltage impulses. Simultaneously, the π bonds in the C=O and C=C double bonds of rapeseed oil and soybean oil are highly reactive, readily absorbing gases such as hydrogen, allowing the coolant to absorb these gases and thus preventing gas generation during storage or use.

[0017] Meanwhile, vegetable oils possess high flash points and high biodegradability, thus this invention can also improve the flash point and biodegradability rate of the coolant. The addition of antioxidants and metal deactivators can compensate for the reduced antioxidant properties caused by vegetable oils, resulting in a coolant with high antioxidant performance. Furthermore, this application uses a blend of soybean oil, rapeseed oil, and synthetic ester oils, which allows the coolant to maintain good viscosity and meet flowability requirements.

[0018] In some embodiments, the synthetic ester oil includes at least one of monoesters, diesters, and polyol esters; wherein the monoester includes the esterification product of a C5-C10 isomeric monohydric alcohol and a C5-C10 monocarboxylic acid; the diester includes the esterification product of neopentyl glycol and a C5-C10 monocarboxylic acid; and the polyol ester includes the esterification product of pentaerythritol and a C5-C10 monocarboxylic acid.

[0019] In the case of monoesters, the C5-C10 monocarboxylic acids can be C5-C10 normal monocarboxylic acids. The C5-C10 monocarboxylic acids in diesters and polyol esters can include C5-C10 straight-chain monocarboxylic acids or C5-C10 branched monocarboxylic acids.

[0020] Esters formed from C5-C10 alcohols and C5-C10 acids have suitable viscosity, which can well meet the viscosity requirements of coolant for base oil.

[0021] In some embodiments, C5-C10 monocarboxylic acids include at least one of octanoic acid, isooctanoic acid, caprylic / decanoic acid, nonanoic acid, isononanoic acid, and heptanoic acid.

[0022] In some embodiments, the polyol ester includes the esterification product of pentaerythritol and 1 to 4 C5 to C10 monocarboxylic acids.

[0023] In some embodiments, the monoester and diester can be prepared independently by solvent dehydration esterification.

[0024] For example, monoesters can be prepared by esterifying a C5-C10 isomeric monohydric alcohol with a C5-C10 monobasic acid. The esterification reaction is carried out at a temperature of 200°C-220°C for 15-20 hours in a solvent (such as an azeotrope of toluene, petroleum ether, or water). This esterification reaction can be carried out without a catalyst. After the esterification reaction is complete, excess acid is removed by vacuum distillation (laboratory scale) or molecular distillation (scale-up to production scale), followed by decolorization with activated carbon and filtration. Alternatively, the above esterification reaction can also be carried out under a protective atmosphere (such as nitrogen) without the need for a solvent.

[0025] Diesters can be prepared by esterifying neopentyl glycol with a C5-C10 monocarboxylic acid. The esterification reaction is carried out at a temperature of 200℃-220℃ for 15-20 hours in a solvent (such as an azeotrope of toluene, petroleum ether, or water). This esterification reaction can be conducted without a catalyst. After the esterification reaction is complete, excess acid is removed by vacuum distillation or molecular distillation, followed by decolorization with activated carbon and filtration. Alternatively, the above esterification reaction can be carried out under a protective atmosphere (such as nitrogen) without the need for a solvent.

[0026] In some embodiments, polyol esters can be prepared by esterifying pentaerythritol with a C5-C10 monocarboxylic acid; the esterification reaction is carried out at a temperature of 200°C-220°C for 15-20 hours; the esterification reaction is catalyzed by a solid acid. Exemplary solid acids include at least one of solid superacids and carbon-based solid acids. After the esterification reaction is completed, excess acid is removed by vacuum distillation or molecular distillation, activated carbon is added for decolorization, and the mixture is filtered.

[0027] In some embodiments, the power frequency breakdown voltage of the vegetable oil is 60-70 kV. The vegetable oil of the present invention has low acid value, low dielectric loss factor, and low moisture content, which enables the vegetable oil to have high insulation properties, thereby exhibiting a high power frequency breakdown voltage, and thus helping to improve the lightning impulse breakdown voltage of the coolant.

[0028] In some embodiments, vegetable oils also include at least one of the following technical parameters:

[0029] Kinematic viscosity at 40℃: 30–36 mm 2 / S;

[0030] Ignition point: 350–370℃.

[0031] The vegetable oil used in this invention has a high flash point, and adding it to the coolant can improve the safety performance of the coolant.

[0032] In some embodiments, vegetable oils include the following technical parameters:

[0033] Acid value: 0.02 mg KOH / g;

[0034] The dielectric loss factor is 0.02.

[0035] Moisture content 80 mg / kg;

[0036] Power frequency breakdown voltage: 65kV;

[0037] Kinematic viscosity at 40℃: 31.8 mmHg 2 / S;

[0038] Ignition point 358℃.

[0039] In some embodiments, the antioxidant includes at least one of phenolic antioxidants and aromatic amine antioxidants. Specifically, phenolic antioxidants may include at least one high molecular weight phenolic ester antioxidant selected from 2,6-di-tert-butyl-p-methylphenol (T501) and isooctyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (L135), and aromatic amine antioxidants include butyloctyl diphenylamine (L57).

[0040] This antioxidant is highly compatible with plant oils and synthetic ester oils, and its antioxidant properties can be significantly improved with a small amount added.

[0041] In some embodiments, the metal deactivator includes at least one of toluene-triazole and its derivatives, and thiadiazole derivatives. Toluene-triazole and its derivatives include I39 (IRGAMET 39, a benzotriazole derivative), and thiadiazole derivatives include T561. This type of metal deactivator has strong coordination ability and exhibits good synergistic effects with phenolic antioxidants, thereby improving the antioxidant properties of the coolant.

[0042] In some embodiments, the antioxidant includes phenolic antioxidants, and the metal deactivator includes toluene-triazole and its derivatives. The two additives exhibit a strong synergistic effect, which can better improve the antioxidant properties of the coolant.

[0043] Secondly, the present invention provides a method for preparing a single-phase immersion coolant, comprising: mixing synthetic ester oil, vegetable oil, antioxidant and metal deactivator.

[0044] In some embodiments, before mixing the synthetic ester oil, vegetable oil, antioxidant, and metal deactivator, the process further includes: adding an adsorbent to the vegetable oil, heating at 50°C to 70°C for 2 to 4 hours, and then filtering. The adsorbent may include at least one of alumina and activated carbon. This heating process can be carried out under vacuum conditions. The mass of the adsorbent is 0.5% to 2% of the vegetable oil. This step removes impurities, reduces moisture, increases the purity of the vegetable oil, reduces acidity, and decreases dielectric loss, thereby improving the power frequency breakdown voltage of the vegetable oil.

[0045] In some embodiments, the mixing temperature is 50°C to 70°C, for example, 60°C; the mixing time is 20 min to 40 min, for example, 30 min. Stirring is used during the mixing process to promote uniform mixing of the components.

[0046] Thirdly, the present invention provides the application of the above-mentioned single-phase immersion coolant in thermal management of at least one of battery energy storage systems and data centers.

[0047] The coolant of this invention has high thermal conductivity, which can meet the heat exchange requirements of high-power equipment such as battery energy storage systems and data centers. At the same time, the coolant's high lightning impulse breakdown voltage, non-gas release, and high ignition point ensure high safety when used for thermal management of various devices. Detailed Implementation

[0048] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0049] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field, which can be obtained by purchase or prepared according to common methods in this technical field.

[0050] Example 1

[0051] A coolant comprising, by weight, 80 parts pentaerythritol ester, 20 parts soybean oil, 0.2 parts T501 and 0.02 parts I39.

[0052] Pentaerythritol ester is an esterification product of pentaerythritol with heptanoic acid, nonanoic acid, and isooctanoic acid, and is prepared by the following method:

[0053] 500g pentaerythritol, 289g heptanoic acid, 201g nonanoic acid, and 246g isooctanoic acid were added to a round-bottom flask. 1g of titanium dioxide solid acid catalyst was added, and the mixture was heated to 220℃ with nitrogen continuously purging. The reaction was carried out for 18 hours. After cooling to 60℃ and maintaining the temperature, excess acid was removed by vacuum distillation. 1% activated carbon was added for decolorization, and the mixture was stirred at 300 rpm for 30 minutes. The final product was obtained by filtration through a 2μm filter membrane.

[0054] The soybean oil was purchased from Yihai Kerry.

[0055] Soybean oil is pretreated before use. The pretreatment method is as follows: 1% alumina and activated carbon are added to soybean oil (the mass ratio between alumina and activated carbon is 1:1). The mixture is stirred in a vacuum reactor and heated to 60°C. After circulating for 3 hours, it is filtered.

[0056] The relevant technical parameters of soybean oil before pretreatment are as follows:

[0057] Acid value: 0.1 mg KOH / g;

[0058] The dielectric loss factor is 0.2.

[0059] Moisture content 480 mg / kg;

[0060] Power frequency breakdown voltage: 35kV;

[0061] Kinematic viscosity at 40℃: 31.4 mmHg 2 / S;

[0062] Ignition point 352℃.

[0063] The relevant technical parameters of the pretreated soybean oil are as follows:

[0064] Acid value: 0.02 mg KOH / g;

[0065] The dielectric loss factor is 0.03.

[0066] Moisture content 80 mg / kg;

[0067] Power frequency breakdown voltage: 65kV;

[0068] Kinematic viscosity at 40℃: 31.8 mmHg 2 / S;

[0069] Ignition point 358℃.

[0070] The test method for acid value is GB / T 264-1983;

[0071] The test method for dielectric loss factor is GB / T 5654-2007;

[0072] The test method for moisture content is GB / T 7600-2014;

[0073] The power frequency breakdown voltage shall be tested in accordance with GB / T 507-2002;

[0074] The test method for kinematic viscosity at 40℃ is GB / T 265-1988;

[0075] The flash point was tested in accordance with GB / T 3536-2008.

[0076] The coolant is prepared by adding soybean oil, T501 and I39 to pentaerythritol ester and stirring at 60°C for 30 minutes.

[0077] Example 2

[0078] The difference between this embodiment and Example 1 is that the type of pentaerythritol ester has been changed. All other conditions are the same as in Example 1.

[0079] Specifically, the pentaerythritol ester in this embodiment is an esterification product of pentaerythritol with heptanoic acid, caprylic / decanoic acid, and isooctanoic acid, and is prepared by the following method:

[0080] 500g of pentaerythritol, 289g of heptanoic acid, 211g of caprylic / capric acid, and 252g of isooctanoic acid were added to a round-bottom flask. 1g of titanium dioxide solid acid catalyst was added, and the mixture was heated to 220℃ with nitrogen continuously purging. The reaction was carried out for 18 hours. After cooling to 60℃ and maintaining the temperature, excess acid was removed by vacuum distillation. 1% activated carbon was added for decolorization, and the mixture was stirred at 300 rpm for 30 minutes. The final product was obtained by filtration through a 2μm filter membrane.

[0081] Example 3

[0082] A coolant, by weight, comprises 70 parts pentaerythritol ester, 30 parts soybean oil, 0.2 parts L135 and 0.02 parts I39, and is prepared by the same method as in Example 1.

[0083] The pentaerythritol ester in this embodiment is an esterification product of pentaerythritol with caprylic / decanoic acid and isooctanoic acid, and is prepared by the following method:

[0084] 500 g of pentaerythritol, 309 g of caprylic / capric acid, and 481 g of isooctanoic acid were added to a round-bottom flask, along with 1 g of titanium dioxide solid acid catalyst. The mixture was heated to 220 °C and continuously purged with nitrogen gas for 18 h. After cooling to 60 °C and maintaining the temperature, excess acid was removed by vacuum distillation. 1% activated carbon was added for decolorization, and the mixture was stirred at 300 r / min for 30 min. The final product was obtained by filtration through a 2 μm filter membrane.

[0085] Example 4

[0086] The difference between this embodiment and Example 3 is that pentaerythritol ester is replaced with a diester. All other conditions are the same as in Example 3.

[0087] The diester in this embodiment is an esterification product of neopentyl glycol and isooctanoic acid (neopentyl isooctanoic acid neopentyl glycol ester), which is prepared by the following method:

[0088] 208 g of neopentyl glycol and 604 g of isooctanoic acid were added to a round-bottom flask, heated to 210 °C, and nitrogen gas was continuously introduced. The reaction was carried out for 16 h. After cooling to 60 °C, the temperature was maintained, and excess acid was removed by vacuum distillation. 1% activated carbon was added for decolorization, and the mixture was stirred at 300 r / min for 30 min. The diester was obtained by filtration through a 2 μm filter membrane.

[0089] Example 5

[0090] The difference between this embodiment and Embodiment 1 is that soybean oil is replaced with rapeseed oil. The relevant technical parameters of rapeseed oil are as follows:

[0091] Acid value: 0.03 mg KOH / g;

[0092] The dielectric loss factor is 0.03.

[0093] Moisture content 71 mg / kg;

[0094] Power frequency breakdown voltage: 64kV;

[0095] Kinematic viscosity at 40℃: 35.15 mmHg 2 / S;

[0096] Ignition point 368℃.

[0097] Other conditions are the same as in Example 1.

[0098] Example 6

[0099] The difference between this embodiment and Example 1 is that pentaerythritol ester is replaced with a monoester.

[0100] The monoester is isooctanol octanoate, and its preparation method is as follows: 520g of isooctanol and 632g of octanoic acid are added to a round-bottom flask, heated to 210℃, and nitrogen is continuously introduced for 13 hours. After cooling to 60℃ and maintaining the temperature, excess acid is removed by vacuum distillation, 1% activated carbon is added for decolorization, and stirring is continued at 300 r / min for 30 min. The resulting ester oil is obtained by filtration through a 2 μm filter membrane. Other conditions are the same as in Example 1.

[0101] Example 7

[0102] The difference between this embodiment and Embodiment 1 is that the mass fraction of each component is adjusted.

[0103] Specifically, by weight, the coolant in this embodiment comprises 50 parts pentaerythritol ester, 50 parts soybean oil, 0.2 parts T501, and 0.02 parts I39. Other conditions are the same as in Example 1.

[0104] Example 8

[0105] The difference between this embodiment and Embodiment 1 is that the mass fraction of each component is adjusted.

[0106] Specifically, by weight, the coolant in this embodiment comprises 90 parts pentaerythritol ester, 10 parts soybean oil, 0.2 parts T501, and 0.02 parts I39. Other conditions are the same as in Example 1.

[0107] Example 9

[0108] The difference between this embodiment and Embodiment 1 is that the mass fraction of each component is adjusted.

[0109] Specifically, by weight, the coolant in this embodiment comprises 80 parts pentaerythritol ester, 20 parts soybean oil, 1 part T501, and 0.02 parts I39. Other conditions are the same as in Example 1.

[0110] Example 10

[0111] The difference between this embodiment and Embodiment 1 is that the mass fraction of each component is adjusted.

[0112] Specifically, by weight, the coolant in this embodiment comprises 80 parts pentaerythritol ester, 20 parts soybean oil, 0.2 parts T501, and 0.05 parts I39. Other conditions are the same as in Example 1.

[0113] Example 11

[0114] The difference between this embodiment and Embodiment 1 is that the mass fraction of each component is adjusted.

[0115] Specifically, by weight, the coolant in this comparative example comprises 45 parts pentaerythritol ester, 55 parts soybean oil, 0.2 parts T501, and 0.02 parts I39. Other conditions are the same as in Example 1.

[0116] Example 12

[0117] The difference between this embodiment and Embodiment 1 is that antioxidant T501 is replaced with L57.

[0118] Example 13

[0119] The difference between this embodiment and Embodiment 1 is that the metal deactivator I39 is replaced with T561.

[0120] Comparative Example 1

[0121] This comparative example uses pentaerythritol ester alone as the coolant.

[0122] This pentaerythritol ester is the same as the pentaerythritol ester in Example 1, both being esterification products of pentaerythritol with heptanoic acid, nonanoic acid, and isooctanoic acid, and prepared by the same method.

[0123] Comparative Example 2

[0124] The difference between this comparative example and Example 1 is that the coolant does not contain soybean oil.

[0125] That is, by mass, the coolant in this comparative example includes 100 parts pentaerythritol ester, 0.2 parts T501 and 0.02 parts I39.

[0126] Comparative Example 3

[0127] The difference between this comparative example and Example 1 is that soybean oil is replaced with castor oil, while other conditions are the same as in Example 1.

[0128] In this comparative example, after mixing and stirring the components, a viscous product was obtained that was not fluid and could not be used as a coolant.

[0129] Comparative Example 4

[0130] The difference between this comparative example and Example 1 is that the mass fractions of each component have been adjusted.

[0131] Specifically, by weight, the coolant in this comparative example comprises 95 parts pentaerythritol ester, 5 parts soybean oil, 0.2 parts T501, and 0.02 parts I39. Other conditions are the same as in Example 1.

[0132] Comparative Example 5

[0133] The difference between this comparative example and Example 1 is that the soybean oil used was not pretreated. The relevant technical parameters of this soybean oil are as follows:

[0134] Acid value: 0.1 mg KOH / g;

[0135] The dielectric loss factor is 0.2.

[0136] Moisture content 480 mg / kg;

[0137] Power frequency breakdown voltage: 35kV;

[0138] Kinematic viscosity at 40℃: 31.4 mmHg 2 / S;

[0139] Ignition point 352℃.

[0140] Comparative Example 6

[0141] The difference between this comparative example and Example 1 is that pentaerythritol ester was replaced with PAO oil (PAO6, purchased from Chevron). All other conditions were the same as in Example 1.

[0142] Comparative Example 7

[0143] The difference between this comparative example and Comparative Example 6 is that the coolant in this example does not contain soybean oil.

[0144] That is, by mass, the coolant in this comparative example includes 100 parts PAO oil, 0.2 parts T501 and 0.02 parts I39.

[0145] The performance of the coolants in each embodiment and comparative example was tested, and the test methods included:

[0146] Thermal conductivity: ASTM D 7896-19;

[0147] Lightning impulse breakdown voltage: GB / T 21222-2007;

[0148] Gas evolution tendency: NB / SH / T 0810-2010;

[0149] Flash point: GB / T 3536-2008;

[0150] Rotating oxygen bomb: ASTM D2272-22;

[0151] Biodegradability: OECD 301F.

[0152] The results are shown in the table below.

[0153] [Table 1]

[0154]

[0155]

[0156] The test results reflect:

[0157] Compared to the coolants in Comparative Examples 1-2 that did not contain vegetable oil, the coolants in Examples 1-13, which were compounded by adding vegetable oils such as soybean oil and rapeseed oil to the synthetic ester, significantly improved the thermal conductivity and lightning impulse breakdown voltage. Furthermore, while the coolants in Comparative Examples 1-2 released gas, the gas release tendency of the coolants in Examples 1-13 changed from positive to negative after the addition of vegetable oil, and gas release no longer occurred. This is likely because the C=O double bonds and the π bonds in the C=C double bonds of vegetable oils are highly reactive, easily absorbing gases such as hydrogen without releasing them. Since no gas is released, flammable gases do not accumulate, thus avoiding the risk of explosion and improving the safety of the coolant.

[0158] Meanwhile, Examples 1-13, by compounding vegetable oil with synthetic esters, can also improve the ignition point, antioxidant properties, and biodegradability of the coolant. Among them, Examples 1-11 use antioxidant T501 and metal deactivator I39 in combination. Compared with Examples 11-12, which use other antioxidants or other metal deactivators, the coolant can have better rotating bomb test results, that is, better antioxidant properties, indicating that T501 and I39 have a good synergistic effect.

[0159] Comparative Example 3 replaced soybean oil with castor oil, resulting in a viscous product that was not fluid and could not be used as a coolant.

[0160] Although soybean oil was also added to pentaerythritol ester in Comparative Example 4, the effect on improving the thermal conductivity of the coolant and the lightning impulse breakdown voltage was limited due to the low amount of soybean oil used.

[0161] Comparative Example 5 did not pretreat the soybean oil, and its acid value, dielectric loss factor and moisture content were too high, resulting in insufficient lightning impulse breakdown voltage of the soybean oil. As a result, the lightning impulse breakdown voltage of the coolant was significantly reduced, and the thermal conductivity and gas evolution tendency were also deteriorated.

[0162] Comparative Example 7 shows that PAO oil also has problems such as low thermal conductivity, low lightning impulse breakdown voltage, and gas release. Comparative Example 6, which blends PAO oil with soybean oil, found that it has limited effect on improving the thermal conductivity, lightning impulse breakdown voltage, and gas evolution tendency of the coolant. At the same time, it also causes a decrease in antioxidant properties. This phenomenon indicates that not all base oils can be blended with soybean oil to improve thermal conductivity, lightning impulse breakdown voltage, and gas evolution tendency.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A single-phase immersion coolant, characterized in that, By weight, it includes the following components: 45-90 parts of synthetic ester oil; 10-55 parts vegetable oil; Antioxidant 0.2 to 1 part; Metal deactivating agent 0.01–0.05 parts; Vegetable oils include at least one of soybean oil and rapeseed oil; The vegetable oil includes the following technical parameters: Acid value: 0.01–0.03 mg KOH / g; The dielectric loss factor is 0.01 to 0.

03. Moisture content: 70–90 mg / kg.

2. The single-phase submersible coolant according to claim 1, characterized in that, The synthetic ester oil includes at least one of monoesters, diesters, and polyol esters; the monoester includes the esterification product of a C5-C10 isomeric monohydric alcohol and a C5-C10 monocarboxylic acid; the diester includes the esterification product of neopentyl glycol and a C5-C10 monocarboxylic acid; and the polyol ester includes the esterification product of pentaerythritol and a C5-C10 monocarboxylic acid.

3. The single-phase immersion coolant according to claim 2, characterized in that, The C5-C10 monocarboxylic acids include at least one of octanoic acid, isooctanoic acid, caprylic / decanoic acid, nonanoic acid, isononanoic acid, and heptanoic acid.

4. The single-phase submersible coolant according to claim 2, characterized in that, The polyol esters include the esterification products of the pentaerythritol and 1 to 4 of the C5 to C10 monocarboxylic acids.

5. The single-phase submersible coolant according to any one of claims 1 to 4, characterized in that, The antioxidants include at least one of phenolic antioxidants and aromatic amine antioxidants; And / or, the metal deactivator includes at least one of toluenetriazole and its derivatives, and thiadiazole derivatives.

6. The single-phase submersible coolant according to claim 5, characterized in that, The phenolic antioxidants include at least one of 2,6-di-tert-butyl-p-methylphenol and isooctyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

7. The single-phase submersible coolant according to claim 5, characterized in that, The antioxidants include phenolic antioxidants, and the metal deactivators include toluenetriazole and its derivatives.

8. A method for preparing a single-phase immersion coolant according to any one of claims 1 to 7, characterized in that, include: The synthetic ester oil, the vegetable oil, the antioxidant, and the metal deactivator are mixed.

9. The method for preparing a single-phase immersion coolant according to claim 8, characterized in that, Before mixing the synthetic ester oil, the vegetable oil, the antioxidant, and the metal deactivator, the process further includes: adding an adsorbent to the vegetable oil, heating it at 50°C to 70°C for 2 to 4 hours, and then filtering it. And / or, the mixing temperature is 50°C to 70°C.

10. The application of the single-phase immersion coolant according to any one of claims 1 to 7 in thermal management of at least one of battery energy storage systems and data centers.

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