Full-time immersed battery cooling liquid, preparation method thereof and full-time immersed battery

Abstract

The invention relates to the field of battery thermal management, in particular to a full-time immersed battery cooling liquid, a preparation method thereof and a full-time immersed battery. The full-time immersed battery cooling liquid comprises the following components in parts by weight: 80-95 parts of a fully synthetic hydrocarbon base liquid; 3-15 parts of a flame retardant additive; 0.5-2 parts of a functional additive; 0.5 to 2 parts of an antioxidant; 0.1-1 part of a corrosion inhibitor; 0.01 to 0.1 part of a defoaming agent; by adding the functional additive, the heat conduction and insulation properties are improved, the inert surface can adsorb free radicals, and oxidative deterioration of hydrogenated PAO is slowed down; for a cooling liquid circulation heat dissipation system, the wear resistance can be improved, the service life of the cooling liquid is prolonged, and the oxidation resistance is improved; the cooling liquid with high specific heat capacity, high flash point, high compatibility and flame retardance is obtained by adding proper flame-retardant additives, antioxidants, corrosion inhibitors, defoaming agents and functional additives, heat generated by batteries can be quickly absorbed, and the thermal runaway condition possibly triggered under extreme conditions is effectively inhibited.

Description

Technical Field

[0001] The present invention relates to the field of battery thermal management, and in particular to a full-time immersion battery coolant and a preparation method thereof, as well as a full-time immersion battery. Background Art

[0002] With the rapid development of new energy vehicles and energy storage power stations, batteries have been widely used as core energy storage devices. Battery performance is sensitive to temperature. High temperatures accelerate the rate of electrochemical reactions, leading to capacity decay and significant heat generation during the charge and discharge process, potentially causing thermal runaway or even explosion. Low temperatures reduce battery activity, leading to capacity decay and increased internal resistance. Therefore, an efficient thermal management system is crucial for battery applications.

[0003] Among battery thermal management methods such as air cooling, liquid cooling, and phase change, liquid cooling offers significant advantages. Immersion cooling has attracted significant attention for its ability to more effectively reduce battery heat, achieve more uniform temperature distribution, and achieve faster cooling. However, current coolants on the market present numerous challenges. Traditional ethylene glycol-based coolants have low specific heat capacity, are flammable, and are unsuitable for immersion cooling. Mineral oil or silicone oil-based coolants have high flash points but insufficient specific heat capacity and may corrode battery materials. Therefore, there is an urgent need to design a high-safety coolant with strong chemical stability, flame retardancy, antioxidant properties, and corrosion inhibition. Summary of the Invention

[0004] The purpose of the present invention is to provide a full-time immersion battery coolant and a preparation method thereof, as well as a full-time immersion battery in view of the deficiencies in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention is to provide a full-time immersion battery coolant, which comprises, by weight:

[0007]

[0008]

[0009] Preferably, the fully synthetic hydrocarbon base fluid comprises at least one of hydrogenated poly-α-olefins, alkyl naphthalenes, isoparaffins, and alkyl benzenes.

[0010] Preferably, the flame retardant additive includes at least one of an organic phosphorus compound, a nitrogen-based melamine cyanurate, a silicon-based organic silicone resin, active silicone powder, and a phosphorus-nitrogen-silicon composite flame retardant.

[0011] Preferably, the functional additive comprises: at least one of surface-modified aluminum oxide nanoparticles and BN nanoparticles.

[0012] Preferably, the antioxidant comprises at least one of phenolic butylated hydroxytoluene, Irganox L-135, amine phenyl-α-naphthylamine, and thiolipid dilauryl thiodipropionate.

[0013] Preferably, the corrosion inhibitor comprises at least one of carboxylic acid dodecenylsuccinic acid, nonylphenoxyacetic acid, and azole benzotriazole.

[0014] Preferably, the defoaming agent includes at least one of polydimethylsiloxane, modified silicone oil, glycerol polyoxypropylene ether, and EO / PO block copolymer.

[0015] The second aspect of the present invention is to provide a method for preparing the above-mentioned full-time immersion battery coolant, comprising the steps of: weighing a fully synthetic hydrocarbon base liquid, a flame retardant additive, a functional additive, an antioxidant, a corrosion inhibitor, and a defoaming agent in parts by weight, heating the fully synthetic hydrocarbon base liquid and stirring it at a constant temperature, adding the flame retardant additive, functional additive, antioxidant, corrosion inhibitor, and defoaming agent in sequence and stirring them evenly, cooling to room temperature, and filtering to obtain the full-time immersion battery coolant.

[0016] Preferably, the temperature of the heating treatment is 40-60° C.; and the filter membrane of the filtration treatment is an acid-resistant and alkali-resistant gradient pore size filter membrane.

[0017] Preferably, the thermal conductivity (40° C.) of the full-time immersion battery coolant is ≥0.21 W / mk.

[0018] Preferably, the specific heat capacity (40° C.) of the full-time immersion battery coolant is ≥2.5 J / kg.

[0019] Preferably, the flash point of the full-time immersion battery coolant is greater than 230°C.

[0020] Preferably, the dielectric strength of the full-time immersion battery coolant is ≥45kV.

[0021] A third aspect of the present invention is to provide a full-time submerged battery, which uses the full-time submerged battery coolant mentioned above or the full-time submerged battery coolant prepared by the above preparation method.

[0022] Preferably, the full-time submerged battery is a full-time submerged lithium battery or a full-time submerged sodium battery.

[0023] The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0024] (1) The coolant of the present invention uses a saturated hydrocarbon compound such as hydrogenated PAO as the base liquid, wherein the isoparaffin branched structure protects the main chain carbon atoms, effectively reducing the oxygen attack sites; the conjugated system of the naphthalene ring or benzene ring absorbs the energy of free radicals, blocks the oxidation chain reaction, and achieves high oxidation stability;

[0025] (2) The addition of the functional additive of the present invention improves thermal conductivity and insulation performance. Its inert surface can adsorb free radicals and slow down the oxidation and deterioration of hydrogenated PAO. It can also improve the anti-wear performance of the coolant circulation and heat dissipation system, and increase the service life and oxidation resistance of the coolant.

[0026] (3) The present invention obtains a coolant with high specific heat capacity, high flash point, high compatibility and flame retardancy by adding suitable flame retardant additives, antioxidants, corrosion inhibitors, defoaming agents and functional additives. The coolant can quickly absorb the heat generated by the battery, effectively suppressing the thermal runaway that may be triggered under extreme conditions, and can achieve overcharging and puncture tests without fire, smoke and obvious structural changes; it also significantly reduces the temperature rise of the battery, realizes continuous backup power, and effectively improves the safety of the battery and the battery overload tolerance;

[0027] (4) The fully synthetic hydrocarbon-based liquid selected in the present invention has the characteristics of a low pour point, can remain stable under extreme conditions such as high and low temperatures, has good low-temperature fluidity, and is biodegradable. It is a relatively environmentally friendly coolant material and is suitable for large-scale promotion and application. DETAILED DESCRIPTION

[0028] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0030] The present invention will be further described below with reference to specific examples, but they are not intended to limit the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a full-time immersion battery coolant, the steps comprising:

[0033] Weigh 90 kg of hydrogenated PAO base liquid and heat it to 45°C. Then, while stirring, add the other components: 8.5 kg of flame retardant phosphate ester (TCPP), 0.5 kg of phenolic antioxidant butylhydroxytoluene (BHT), 0.48 kg of corrosion inhibitor benzotriazole (BTA), 0.02 kg of defoaming agent polydimethylsiloxane, and 0.5 kg of silanized aluminum oxide. Stir until thoroughly mixed. Cool the mixture to room temperature and filter to obtain a uniformly colored coolant.

[0034] The mass proportions of the coolant components are: hydrogenated PAO: flame retardant additive: antioxidant: corrosion inhibitor: defoaming agent: functional additive = 90%: 8.5%: 0.5%: 0.48%: 0.02%: 0.5%.

[0035] Example 2

[0036] This embodiment provides another method for preparing a full-time immersion battery coolant, the steps comprising:

[0037] Weigh 85 kg of alkyl naphthalene and heat it to 45°C. Then, while stirring, add the other components: 12.5 kg of flame retardant phosphate (TCPP), 1.0 kg of antioxidant phenyl-α-naphthylamine, 0.98 kg of corrosion inhibitor benzotriazole (BTA), 0.02 kg of defoamer glycerol polyoxypropylene ether, and 0.5 kg of silanized aluminum oxide. Stir until thoroughly mixed. Cool the mixture to room temperature and filter to obtain a uniformly colored coolant.

[0038] The mass proportions of the components of the coolant are: alkyl naphthalene: flame retardant additive: antioxidant: corrosion inhibitor: defoaming agent: functional additive = 85%: 12.5%: 1%: 0.98%: 0.02%: 0.5%.

[0039] Example 3

[0040] This embodiment provides another method for preparing a full-time immersion battery coolant, the steps comprising:

[0041] Weigh 90 kg of hydrogenated PAO base liquid and heat it to 45°C. Then, while stirring, add the other components: 8.5 kg of flame retardant phosphate ester (TCPP), 0.5 kg of antioxidant dilauryl thiodipropionate, 0.48 kg of corrosion inhibitor nonylphenoxyacetic acid, 0.02 kg of defoamer EO / PO block copolymer, and 0.5 kg of silanized BN nanoparticles. Stir until thoroughly mixed. Cool the mixture to room temperature and filter to obtain a uniformly colored coolant.

[0042] The mass proportions of the coolant components are: hydrogenated PAO: flame retardant additive: antioxidant: corrosion inhibitor: defoaming agent: functional additive = 90%: 8.5%: 0.5%: 0.48%: 0.02%: 0.5%.

[0043] Comparative Example 1

[0044] This comparative example provides a method for preparing a battery coolant, comprising the following steps:

[0045] Heat 100 kg of hydrogenated PAO base liquid to 45°C. Then, while stirring, add the other components: 9 kg of flame retardant melamine cyanurate (MCA), 0.5 kg of phenolic antioxidant butylhydroxytoluene (BHT), 0.48 kg of corrosion inhibitor benzotriazole (BTA), and 0.02 kg of defoamer. Stir until thoroughly mixed. Cool the mixture to room temperature and filter to obtain a uniform coolant. The mass ratio of the coolant components is: hydrogenated PAO: flame retardant: antioxidant: corrosion inhibitor: defoamer = 90%: 9%: 0.5%: 0.48%: 0.02%.

[0046] Comparative Example 2

[0047] This comparative example provides another method for preparing a battery coolant, comprising the following steps:

[0048] Heat 90 kg of hydrogenated PAO base liquid to 45°C. Then, add 0.5 kg of silanized aluminum oxide while stirring until thoroughly mixed. Cool the mixture to room temperature and filter to obtain a uniform coolant. The mass ratio of the coolant components is: hydrogenated PAO: functional additive = 99.5%: 0.5%.

[0049] Comparative Example 3

[0050] This comparative example provides another method for preparing a battery coolant, comprising the following steps:

[0051] Use only hydrogenated PAO base fluid as coolant.

[0052] Detection Example

[0053] The coolants prepared by the preparation methods described in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test results are shown in Table 1;

[0054] Table 1

[0055] sample Specific heat capacity J / (g·K) Flash point (℃) Dielectric strength (2.58MM, kV) Thermal conductivity (40℃) Example 1 2.52 245 48 0.26 Example 2 2.38 240 53 0.21 Example 3 2.60 245 50 0.35 Comparative Example 1 2.19 230 43.2 0.17 Comparative Example 2 2.23 235 44 0.18 Comparative Example 3 2.0 230 40 0.15

[0056] The coolants prepared by the formulas of Examples 1 and 3 have good flash point, specific heat capacity, thermal stability, dielectric strength and other important technical indicators, but the cost of the functional additives in Example 3 is higher than that in Example 1, so the coolant in Example 1 is the best; compared with Comparative Example 1, the addition of the functional additives in Example 1 significantly improves the specific heat capacity, flash point, dielectric strength and thermal conductivity of the coolant.

[0057] The coolant in Example 1 was used to prepare a full-time immersion battery, and the fully immersion battery was tested for its high efficiency in absorbing the heat generated during battery operation. Under a power of 250kW, the discharge temperature rise of the immersion battery was <45°C, and it could be continuously charged and discharged after one discharge. However, under the same conditions, the discharge temperature rise of a conventional battery was >61°C, and it needed to be cooled after one discharge, and it took about 10 hours to achieve a second discharge. This shows that the coolant of the present invention enables the immersion battery to achieve continuous backup power. In addition, the battery discharge power of Comparative Example 3 can only reach 272kW, while the immersion battery of the present invention has a discharge power of up to 540kW, that is, the full-time immersion battery of the present invention has a higher discharge power. The coolant in the full-time immersion battery fills the air in the gap between the battery and the cabinet, and its good thermal conductivity enables rapid heat dissipation.

[0058] In order to further verify the safety performance, the coolants of Examples 1-3 and conventional coolants on the market were subjected to full immersion overcharge, short circuit and puncture tests under extreme conditions. In the anti-overcharge test, the temperature of several temperature measuring points of the immersed battery changed smoothly below 40°C, and the highest temperature point was <70°C. Without the addition of coolant, the lowest temperature measuring point was >100°C, up to 250°C, and the high temperature lasted for a long time. In the anti-puncture and short-circuit tests, the coolant-immersed battery did not catch fire or smoke, and very little gas was generated, while conventional coolants would produce a large amount of smoke and flammable gas. This is because after the explosion-proof valve is opened, the coolant enters the battery and quickly takes away the heat, achieving rapid cooling.

[0059] To test the insulation capability, the breakdown strength of the immersed battery was tested to be ≥58kV. Even when the battery explosion-proof valve was opened and a small amount of particles or leaked electrolyte mixed with the coolant, the breakdown strength was still >10kV. Therefore, the coolant and battery of the present invention exhibited good insulation performance, and the coolant and electrolyte had good compatibility.

[0060] In summary, the coolant prepared by the present invention exhibits a high flash point, large specific heat capacity, good thermal stability, high dielectric strength, low-temperature fluidity, and good compatibility with other materials. These characteristics significantly enhance battery safety, extend service life, and significantly improve the electrochemical performance of submerged batteries. Furthermore, it offers significant cost advantages, a long service life, and is suitable for a wide range of applications.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the present invention specification should be included in the protection scope of the present invention.

Claims

1. A full-time immersion battery coolant, characterized in that: By weight, the components include:

2. The full-time immersion battery coolant according to claim 1, characterized in that: The fully synthetic hydrocarbon base fluid comprises at least one of hydrogenated poly-alpha-olefin, alkyl naphthalene, isoparaffin, and alkyl benzene.

3. The full-time immersion battery coolant according to claim 1, characterized in that: The flame retardant additive comprises at least one of an organic phosphorus compound, a nitrogen-based melamine cyanurate, a silicon-based organic silicone resin, active silicone powder, and a phosphorus-nitrogen-silicon composite flame retardant.

4. The full-time immersion battery coolant according to claim 1, characterized in that: The functional additive comprises at least one of surface-modified aluminum oxide nanoparticles and BN nanoparticles.

5. The full-time immersion battery coolant according to claim 1, characterized in that: The antioxidant comprises at least one of phenolic butylated hydroxytoluene, Irganox L-135, amine phenyl-α-naphthylamine, and thiolipid dilauryl thiodipropionate.

6. The full-time immersion battery coolant according to claim 1, characterized in that: The corrosion inhibitor comprises at least one of carboxylic acid-based dodecenylsuccinic acid, nonylphenoxyacetic acid, and azole-based benzotriazole.

7. The full-time immersion battery coolant according to claim 1, characterized in that: The defoaming agent comprises at least one of polydimethylsiloxane, modified silicone oil, glycerol polyoxypropylene ether, and EO / PO block copolymer.

8. A method for preparing a full-time immersion battery coolant according to any one of claims 1 to 7, characterized in that the steps include: A fully synthetic hydrocarbon base liquid, a flame retardant additive, a functional additive, an antioxidant, a corrosion inhibitor, and a defoaming agent are weighed in parts by weight, the fully synthetic hydrocarbon base liquid is heated and stirred at a constant temperature, the flame retardant additive, functional additive, antioxidant, corrosion inhibitor, and defoaming agent are added in sequence and stirred evenly, and the mixture is cooled to room temperature and filtered to obtain the full-time immersion battery coolant.

9. The preparation method according to claim 8, characterized in that The temperature of the heating treatment is 40-60° C.; the filter membrane of the filtration treatment is an acid-resistant and alkali-resistant gradient pore size filter membrane.

10. A full-time immersion battery, characterized in that: A full-time immersion battery coolant prepared by the full-time immersion battery coolant according to any one of claims 1 to 7 or the preparation method according to any one of claims 8 to 9.

Images