Preparation process of explosion-proof immersion liquid with high heat exchange rate

Abstract

The invention discloses a preparation process of an explosion-proof immersion liquid with high heat exchange rate, which belongs to the technical field of energy storage, and comprises the following steps: step 1, providing a basic liquid with the characteristics of high insulativity, high boiling point and low viscosity, step 2, uniformly dispersing at least one heat-conducting filler in the basic liquid to form a mixed liquid with high heat exchange rate, 3, at least one microencapsulated flame retardant is doped into the mixed solution, and a wall material of the microencapsulated flame retardant is configured to be broken and release internal flame-retardant substances when the temperature reaches a first preset temperature, 4, at least one oxygen-triggered curing component is doped into the mixed solution, and the oxygen-triggered curing component is prepared. The oxygen-triggered curing component is configured to be in contact with ambient oxygen. When local thermal runaway occurs, a fire extinguishing mechanism can be instantly started, and explosion suppression is effectively achieved. If leakage occurs in the system, the system can rapidly sense leakage and solidify and block the leakage point, self-healing is achieved, and the cooling function is prevented from losing efficacy.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a process for preparing an explosion-proof immersion liquid with high heat exchange rate. Background Technology

[0002] Immersion cooling is an effective solution to the heat dissipation challenges of high-density electronic devices. The performance of its core medium—the immersion fluid—directly determines the system's thermal management efficiency and safety level. Currently, immersion fluid technologies on the market mainly fall into the following categories, all of which have significant limitations:

[0003] First, inert coolants, represented by fluorinated liquids. These liquids (such as perfluoropolyethers) are chemically extremely stable, possess excellent electrical insulation and non-flammability, and were the mainstream choice for early immersion cooling. However, their inherent drawbacks are quite prominent: First, the cost of raw materials is extremely high, severely restricting large-scale commercial applications; second, their basic thermophysical properties (such as thermal conductivity and specific heat capacity) are generally low, resulting in a natural bottleneck in their heat exchange efficiency, making it difficult to meet the heat dissipation requirements of future higher-power equipment; in addition, some fluorides have high global warming potential (GWP), which contradicts increasingly stringent environmental protection requirements.

[0004] Second, there are economical coolants, such as mineral oil or synthetic esters. These liquids are relatively inexpensive and have a higher specific heat capacity than fluorinated liquids, giving them an advantage in heat dissipation. However, their core weakness lies in safety: mineral oil has a low flash point and poses a flammability risk. If equipment (such as energy storage batteries) experiences thermal runaway, the immersion liquid itself may become fuel, exacerbating the fire. Although this can be improved by adding flame retardants, conventional flame retardants may affect the liquid's stability or insulation performance, offering only a temporary solution.

[0005] Third, in terms of function, all existing technologies are "passive" cooling media. Their function is limited to heat conduction and convection during normal system operation, and they cannot provide active safety protection when the system fails. When the cooling system leaks due to an accident, the existing immersion fluid will continue to flow out, causing the equipment to overheat and be damaged rapidly due to the lack of cooling medium; when the battery experiences an internal short circuit that triggers thermal runaway, the existing liquids also lack an active fire extinguishing and explosion suppression mechanism, and can only allow the accident to escalate.

[0006] In summary, existing immersion fluid technologies cannot achieve a balance between cost, heat exchange efficiency, and active safety protection (fire suppression and leak prevention) in the three key dimensions. Therefore, it is necessary to develop a technology that combines high heat exchange rate, intelligent active safety functions, and cost-effectiveness. Summary of the Invention

[0007] The purpose of this invention is to provide a high-heat-exchange-rate explosion-proof immersion fluid preparation process. This invention breaks through the technical bottleneck of traditional immersion fluids with limited performance characteristics, achieving a leapfrog improvement in overall performance. It not only significantly improves heat exchange efficiency, ensuring continuous and stable heat dissipation of the system, but also innovatively endows the immersion fluid with intelligent active protection capabilities. In the event of localized thermal runaway, it can instantly activate a fire extinguishing mechanism to effectively suppress explosions. If a leak occurs in the system, it can quickly detect it and solidify and seal the leak point, achieving self-healing and preventing cooling function failure. This technology successfully integrates efficient thermal management, active safety protection, and long-term stable operation, while also taking into account cost advantages and environmental protection characteristics, providing unprecedented comprehensive protection for high-density electronic equipment.

[0008] To achieve the above effects, the present invention provides the following technical solution: a process for preparing an explosion-proof immersion liquid with high heat exchange rate, comprising the following steps:

[0009] Step 1: Provide a base liquid with high insulation, high boiling point and low viscosity.

[0010] Step 2: Disperse at least one thermally conductive filler uniformly in the base liquid to form a mixture with a high heat exchange rate.

[0011] Step 3: Incorporate at least one microencapsulated flame retardant into the mixture, wherein the wall material of the microencapsulated flame retardant is configured to rupture and release the internal flame retardant material upon reaching a first predetermined temperature.

[0012] Step 4: Incorporate at least one oxygen-triggered curing component into the mixture. The oxygen-triggered curing component is configured to undergo a cross-linking reaction and cure upon contact with ambient oxygen, thereby sealing the leakage gap.

[0013] Furthermore, the base fluid is one or more of hydrogenated mineral oil, synthetic ester, or modified silicone oil, with a kinematic viscosity at 40°C between 3 and 15 cSt and a boiling point not lower than 200°C.

[0014] Furthermore, the thermally conductive filler includes one or more of nano-aluminum nitride, nano-alumina, or nano-boron nitride that have undergone surface modification treatment, with an addition mass fraction of 0.5%-5%.

[0015] Furthermore, the wall material of the microencapsulated flame retardant is a thermoplastic polymer with a melting point between 80°C and 120°C, and the internal flame retardant is one of perfluorohexanone, heptafluoropropane, or phosphate ester flame retardants.

[0016] Furthermore, the oxygen-triggered curing component is a modified silane compound or a combination of terminal alkenyl silicone oil and hydrogen-containing silicone oil, and contains a platinum catalyst.

[0017] Furthermore, the oxygen-triggered curing component is stable at room temperature. When the immersion liquid comes into contact with a large amount of ambient oxygen through the leak point, a hydrosilylation reaction occurs under the catalysis of the platinum catalyst, and the elastomer is rapidly cured within 1-5 minutes.

[0018] Furthermore, in addition to the oxygen-triggered curing component, a surface modifier is also incorporated. The surface modifier is a polyether-modified siloxane or a fatty acid derivative, and its mass fraction is 0.1%-1% to improve the dispersion stability of each component in the base liquid.

[0019] Furthermore, the step of uniformly dispersing the thermally conductive filler in the base liquid specifically includes: first, pre-dispersing a portion of the base liquid and the thermally conductive filler in a high-speed shear machine at a speed of 8000-12000 rpm for 10-30 minutes, then subjecting it to ultrasonic treatment for 0.5-2 hours, and finally mixing it with the remaining base liquid.

[0020] Furthermore, the microencapsulated flame retardant and the oxygen-triggered curing component are added sequentially under low-speed stirring conditions, with the stirring speed controlled at 200-500 rpm and the stirring time at 30-60 minutes, to avoid damaging the physical structure of each component.

[0021] A high heat exchange rate explosion-proof immersion liquid prepared according to any one of the above-described preparation processes, which simultaneously possesses:

[0022] The thermal conductivity is not less than 0.18 W / m·K.

[0023] It has the ability to actively plug leaks under specific triggering conditions.

[0024] It has the function of active fire extinguishing and explosion suppression under thermal abuse conditions.

[0025] This invention provides a process for preparing an explosion-proof immersion liquid with high heat exchange rate, which has the following beneficial effects:

[0026] (1) This invention achieves a significant leap in the heat exchange efficiency of the immersion liquid. By uniformly and stably dispersing surface-modified nanoscale thermally conductive fillers (such as nano-boron nitride) in the base liquid under optimized processes, the thermal conductivity of the liquid is fundamentally improved. Test data shows that the thermal conductivity of the immersion liquid of this invention reaches 0.198 W / m·K, which is significantly better than traditional mineral oil and commercial fluorinated liquid. Combined with its high specific heat capacity, in simulated continuous heat dissipation tests, it can extend the time for maintaining the system temperature within the safe threshold by about 40%, providing a more reliable thermal management guarantee for high power density electronic devices.

[0027] (2) This invention endows the immersion liquid with "intelligent" active fire prevention and explosion suppression capabilities. The built-in microencapsulated flame retardant is like thousands of "mini fire extinguishers" distributed in the liquid. When the local temperature rises abnormally due to thermal runaway and exceeds the melting point of the wall material, the capsules rupture rapidly and release highly efficient vaporized flame retardant (such as perfluorohexanone) instantly. It can immediately suffocate open flames and strongly suppress the thermal runaway chain reaction of the battery. Its response speed is within 1 second, which fundamentally eliminates the risk of continuous combustion and explosion inside the liquid and upgrades post-event remediation to in-event prevention.

[0028] (3) This invention innovatively introduces a "self-healing" leak-proof function to the immersion fluid system. When the cooling system is damaged due to accident and the immersion fluid leaks, the oxygen-triggered curing component mixed in can quickly cross-link and solidify under the action of platinum catalyst once it comes into contact with the outside air, forming an elastic solid seal plug at the leak gap. Experiments have shown that it can effectively seal a 3mm gap within 2 minutes, thereby greatly delaying or even preventing the loss of coolant, preserving the cooling capacity of the system, winning valuable time for fault repair, and avoiding secondary disasters caused by the loss of cooling medium.

[0029] (4) This invention successfully integrates multiple contradictory characteristics such as high heat exchange rate, active safety and long-term stability. By using surface modifiers and precise stepwise mixing processes, the technical problems of easy agglomeration of nanofillers and easy breakage of microcapsules are effectively solved, ensuring the physical stability and chemical inertness of the product during long-term use and storage. This allows it to dissipate heat as efficiently as advanced synthetic fluids, while also possessing the economic advantages of mineral oil. At the same time, it surpasses the capabilities of all traditional products in terms of intelligent safety protection, achieving a perfect balance of performance.

[0030] (5) This invention improves overall performance while taking into account cost control and environmental protection. Using refined mineral oil or synthetic ester as the main base liquid significantly reduces raw material costs compared to expensive perfluoropolyether base liquids. The functional additives used are all micro-volume high-efficiency types, and the energy consumption and waste in the production process are reduced through process optimization. This invention's products have a high cost-performance ratio and are in line with the development direction of green manufacturing, clearing obstacles for large-scale industrial applications. Attached Figure Description

[0031] Figure 1 This is a schematic flowchart of a high heat exchange rate explosion-proof immersion liquid preparation process according to the present invention.

[0032] Figure 2 This is a schematic diagram of the immersion temperature curve of the explosion-proof immersion liquid preparation process with high heat exchange rate according to the present invention.

[0033] Figure 3This is a schematic diagram comparing the safety performance of a high heat exchange rate explosion-proof immersion liquid preparation process according to the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0035] This invention provides a technical solution: Please refer to Figures 1-3 Example 1: A high heat exchange rate explosion-proof immersion liquid formulation:

[0036] Base fluid: Hydrogenated refined mineral oil, kinematic viscosity at 40°C: 8 cSt, boiling point: 250°C. (Dosage: 95.5% of total mass)

[0037] Thermally conductive filler: Nano-boron nitride (n-BN) with a surface modified by a silane coupling agent. (Dosage: 2% of total mass)

[0038] Microencapsulated flame retardant: Using low-melting-point polypropylene as the wall material, encapsulating perfluorohexanone; average capsule particle size 15μm; bursting temperature 90℃. (Dosage: 2% of total mass)

[0039] Oxygen-triggered curing component: A mixture of terminal alkenyl silicone oil and hydrogen-containing silicone oil, containing trace amounts of platinum catalyst. (Dosage: 0.5% of total mass)

[0040] Surface modifier: Polyether-modified siloxane. (Dosage: 0.1% of total mass)

[0041] The preparation of an explosion-proof immersion liquid with high heat exchange rate includes the following steps:

[0042] Pre-dispersion: Add half of the base liquid, all of the nano boron nitride and surface modifier to a high-speed shear disperser and shear disperse at 10,000 rpm for 20 minutes.

[0043] Nanoparticle processing: The above mixture was transferred to an ultrasonic cell disruptor and ultrasonically treated at 800W power for 1 hour to ensure that the nanofiller was fully dispersed and that there was no visible agglomeration.

[0044] Base liquid mixing: Add the remaining base liquid and mix evenly with low-speed stirring (300 rpm) to form a uniform and stable high thermal conductivity mixture.

[0045] Functional component addition: Microencapsulated flame retardant and oxygen-triggered curing component were added to the mixture in sequence under low-speed stirring at 300 rpm. Each component was stirred for 40 minutes after addition to ensure uniform dispersion and without damaging the microcapsule structure.

[0046] Aging and Filtration: The final product is left to stand at 25°C for 24 hours, and then filtered through a 500-mesh filter to obtain the high heat exchange rate explosion-proof immersion liquid described in this invention.

[0047] Comparative Example 1: Traditional mineral oil-based immersion solution

[0048] Ingredients: Same type of hydrogenated refined mineral oil, no added functional fillers.

[0049] Comparative Example 2: Commercial Fluorinated Liquid

[0050] Ingredients: A single-component perfluoropolyether liquid from a certain brand.

[0051] Performance testing and comparative analysis:

[0052] The three immersion solutions were placed under the same test conditions to compare their key performance characteristics.

[0053] Comparison of basic heat exchange performance:

[0054] The thermal conductivity and specific heat capacity of three liquids were tested in the temperature range of 40℃ to 60℃, and the results are as follows:

[0055] Table 1: Comparison of Basic Thermophysical Properties

[0056] Performance indicators This invention Comparative Example 1 (Conventional Mineral Oil) Comparative Example 2 (Commercial Fluorinated Liquid) Thermal conductivity (W / m·K) 0.198 0.145 0.165 Specific heat capacity (J / g·K) 2.05 1.85 1.10

[0057] Continuous heat dissipation capacity simulation test:

[0058] A test platform simulating battery pack heating was constructed, using constant power heating to monitor the rate of temperature rise of the immersion fluid. The longer it takes for the temperature to reach a preset safety threshold (e.g., 70°C), the stronger the fluid's continuous heat dissipation capacity. Detailed parameters are attached. Figure 2 .

[0059] Active safety performance testing

[0060] Leakage sealing test:

[0061] Create a 3mm diameter notch at the bottom of the container and observe the leakage of the immersion liquid under gravity.

[0062] Table 2: Comparison of Leakage Plugging Performance

[0063] Test Project This invention Comparative Examples 1 & 2 Initial leak have have Changes after contact with air An elastic seal is formed at the gap, and the leakage stops within 2 minutes. Continue leaking until the liquid level is below the gap. Final result The leak was successfully contained, and most of the liquid was preserved. All liquid lost

[0064] Fire extinguishing and explosion suppression performance test:

[0065] A nickel-chromium alloy wire heated to 500°C is inserted into the immersion liquid to simulate the thermal runaway trigger point.

[0066] Comparative Example 1 (Traditional Mineral Oil): Upon contact, a large amount of white smoke is produced, accompanied by an open flame, and it continues to burn.

[0067] Comparative Example 2 (commercial fluorinated liquid): It does not burn, but produces a large amount of vapor, and the liquid itself has no active fire extinguishing chemical effect.

[0068] This invention: Upon contact with the heating wire, the surrounding microcapsules rapidly rupture, releasing perfluorohexanone flame retardant, which suppresses the generation of vapor within 1 second, resulting in smokeless and flameless operation.

[0069] The results were compared using "whether it ignites" and "whether it suppresses explosions" as key indicators. Figure 3 :

[0070] Conclusion: This embodiment, through detailed formulation, process, and simulation test data, fully verifies the feasibility and excellence of the immersion liquid preparation process described in this invention. Compared with existing technologies, the product of this invention not only provides a basic improvement in heat exchange performance but also achieves "intelligent" active safety protection. It can automatically activate fire extinguishing and sealing mechanisms in the event of an accident, effectively preventing catastrophic thermal runaway and providing a safer and more reliable solution for immersion cooling of high-density electronic equipment.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for preparing an explosion-proof immersion liquid with high heat exchange rate, characterized in that, Includes the following steps: Step 1: Provide a base liquid with high insulation, high boiling point and low viscosity. Step 2: Disperse at least one thermally conductive filler uniformly in the base liquid to form a mixture with a high heat exchange rate; Step 3: Incorporate at least one microencapsulated flame retardant into the mixture, wherein the wall material of the microencapsulated flame retardant is configured to rupture and release the internal flame retardant material upon reaching a first predetermined temperature; Step 4: Incorporate at least one oxygen-triggered curing component into the mixture. The oxygen-triggered curing component is configured to undergo a cross-linking reaction and cure upon contact with ambient oxygen, thereby sealing the leakage gap.

2. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The base fluid is one or more of the following: hydrogenated refined mineral oil, synthetic ester, or modified silicone oil, with a kinematic viscosity at 40°C between 3 and 15 cSt and a boiling point not lower than 200°C.

3. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The thermally conductive filler includes one or more of nano-aluminum nitride, nano-alumina, or nano-boron nitride that have undergone surface modification treatment, with an addition mass fraction of 0.5%-5%.

4. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The wall material of the microencapsulated flame retardant is a thermoplastic polymer with a melting point between 80°C and 120°C, and the internal flame retardant is one of perfluorohexanone, heptafluoropropane, or a phosphate ester flame retardant.

5. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The oxygen-triggered curing component is a modified silane compound or a combination of terminal alkenyl silicone oil and hydrogen-containing silicone oil, and contains a platinum catalyst.

6. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The oxygen-triggered curing component is stable at room temperature. When the immersion liquid comes into contact with a large amount of ambient oxygen through the leak point, a hydrosilylation reaction occurs under the catalysis of the platinum catalyst, and the elastomer is rapidly cured within 1-5 minutes.

7. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, In addition to the oxygen-triggered curing component, a surface modifier is also incorporated. The surface modifier is a polyether-modified siloxane or a fatty acid derivative, and its mass fraction is 0.1%-1% to improve the dispersion stability of each component in the base liquid.

8. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The step of uniformly dispersing the thermally conductive filler in the base liquid specifically includes: first, pre-dispersing a portion of the base liquid and the thermally conductive filler in a high-speed shear machine at a speed of 8000-12000 rpm for 10-30 minutes, then subjecting it to ultrasonic treatment for 0.5-2 hours, and finally mixing it with the remaining base liquid.

9. The process for preparing an explosion-proof immersion liquid with high heat exchange rate according to claim 1, characterized in that, The microencapsulated flame retardant and the oxygen-triggered curing component are added sequentially under low-speed stirring conditions, with the stirring speed controlled at 200-500 rpm and the stirring time at 30-60 minutes, to avoid damaging the physical structure of each component.

10. A high heat exchange rate explosion-proof immersion liquid prepared according to any one of claims 1-9, characterized in that, It simultaneously possesses: Thermal conductivity not less than 0.18 W / m·K; It has the ability to actively plug leaks under specific triggering conditions; It has the function of active fire extinguishing and explosion suppression under thermal abuse conditions.

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