Battery cell immersion type cooling liquid for energy storage and preparation method of battery cell immersion type cooling liquid

Abstract

The invention provides an energy storage battery cell immersed cooling liquid, which is composed of the following components in parts by weight: 83 to 95 parts of base oil, 3.5 to 12 parts of alkyl naphthalene, 0.5 to 3 parts of antioxidant, 0.5 to 3 parts of corrosion inhibitor, and 0.5 to 1 part of inhibitor. The invention also provides a preparation method of the energy storage battery cell immersed cooling liquid. The prepared immersed cooling liquid for the battery cell for energy storage not only has high heat conduction efficiency and high specific heat capacity, but also is stable in performance, and can be compatible with various additives, so that the risk of corroding equipment is reduced, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of energy storage batteries, and in particular to an immersion type cooling liquid for an energy storage battery and a preparation method thereof. Background Art

[0002] At present, with the continuous development of industrial technology, the demand for energy is getting higher and higher, and the demand for energy storage batteries is also getting higher and higher. The energy storage system needs to be controlled at a suitable temperature during operation, so the energy storage system needs to be cooled. Therefore, thermal management of energy storage batteries has become a key challenge in the field of energy storage battery technology.

[0003] In the prior art, energy storage batteries generally dissipate heat through air cooling, liquid cooling, and immersion cooling. The heat dissipation efficiency of air cooling and liquid cooling for energy storage batteries is far less than that of immersion cooling. Immersion cooling is to immerse the battery module directly in the coolant, which can effectively control the battery temperature and improve the heat conduction efficiency, thereby ensuring the stability and safety of the battery pack under high-power discharge or charging conditions. This direct contact thermal management method greatly improves the heat transfer efficiency, reduces thermal resistance, and helps to reduce the temperature rise of the battery pack and extend its service life.

[0004] Immersion coolant plays an important role in the heat dissipation of energy storage batteries. Immersion coolant has a significant impact on the heat dissipation efficiency, equipment materials and service life of energy storage batteries. Therefore, it is necessary to develop a new type of immersion coolant with high thermal conductivity, high specific heat capacity and compatible with equipment materials. Summary of the invention

[0005] The object of the present invention is to provide an immersion coolant for energy storage batteries and a preparation method thereof, aiming to solve or at least partially solve the deficiencies of the above-mentioned background technology. The immersion coolant for energy storage batteries not only has high thermal conductivity and high specific heat capacity, but also has stable performance. In addition, it is also compatible with various additives to reduce the risk of corrosion of equipment and extend the service life of the equipment.

[0006] The invention provides an immersion coolant for an energy storage battery. The immersion coolant for an energy storage battery consists of the following components in parts by weight: 83-95 parts of base oil, 3.5-12 parts of alkyl naphthalene, 0.5-3 parts of antioxidant, 0.5-3 parts of corrosion inhibitor, and 0.5-1 part of inhibitor.

[0007] Further, the base oil is PAO (polyalphaolefin).

[0008] Furthermore, the antioxidant is at least one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, and 2,6-di-tert-butyl-α-dimethylamino-p-cresol.

[0009] Furthermore, the corrosion inhibitor is at least one of diethanolamine, isooctanoic acid, and tolyltriazole.

[0010] Furthermore, the inhibitor is at least one of a benzotriazole derivative and a methylbenzotriazole derivative.

[0011] The present invention also provides a method for preparing the above-mentioned energy storage battery core immersion coolant, comprising the following steps: S1. Add base oil into a container; S2, add alkylnaphthalene into the container and stir evenly; S3. Slowly add the corrosion inhibitor into the container and stir evenly; S4, adding an inhibitor and an antioxidant to the container in sequence; S5. Pour the mixed liquid in the container into a stirring tank and stir it evenly.

[0012] Furthermore, the stirring time of the stirring tank in step S5 is 30 min.

[0013] Furthermore, the stirring speed of the stirring tank in step S5 is 110 r / min to 150 r / min.

[0014] Furthermore, the humidity during stirring in the stirring tank in step S5 is controlled at 35% to 50%.

[0015] Furthermore, the temperature during stirring in the stirring tank in step S5 is controlled at 130° C. to 145° C.

[0016] The present invention provides an immersion coolant for energy storage battery cells. By adding alkyl naphthalene, on the one hand, the kinematic viscosity of the base oil can be reduced, the fluidity of the immersion coolant for energy storage battery cells can be improved, so that it is easier to flow and transfer heat in the equipment, thereby improving the thermal conductivity efficiency. On the other hand, the amount of antioxidant, corrosion inhibitor and inhibitor added can be reduced while maintaining the same performance level of the immersion coolant for energy storage battery cells. By adding antioxidant, the contact parts in the liquid-cooled energy storage system can be effectively protected from the influence of oxidative corrosion. By adding corrosion inhibitor, a chemical reaction can occur with the metal surface to form a protective film, thereby slowing down the corrosion rate of the metal and reducing equipment damage caused by corrosion, thereby improving the material compatibility of the immersion coolant for energy storage battery cells and extending the equipment life. By adding inhibitor, the situation of excessive foam generated during the preparation process of the immersion coolant for energy storage battery cells can be alleviated, avoiding the generated foam from affecting the performance of the immersion coolant for energy storage battery cells, and improving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic flow chart of a method for preparing an immersion cooling liquid for an energy storage battery cell. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0019] The terms "first", "second", "third", "fourth" and the like (if any) in the description and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a particular sequence or order.

[0020] The directional words such as up, down, left, right, front, back, top, bottom, etc. (if any) involved in the specification and claims of the present invention are defined by the positions of the structures in the drawings and the positions of the structures relative to each other, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional words should not limit the scope of protection claimed in this application.

[0021] The invention discloses an immersion coolant for an energy storage battery cell. The immersion coolant for an energy storage battery cell consists of the following components in parts by weight: 83-95 parts of base oil, 3.5-12 parts of alkyl naphthalene, 0.5-3 parts of antioxidant, 0.5-3 parts of corrosion inhibitor and 0.5-1 parts of inhibitor.

[0022] By adding alkylnaphthalene, on the one hand, the kinematic viscosity of the base oil can be reduced, which can improve the fluidity of the energy storage battery cell immersion coolant, making it easier to flow and transfer heat in the equipment, thereby improving the thermal conductivity. On the other hand, the amount of antioxidants, corrosion inhibitors, and inhibitors added can be reduced while maintaining the same performance level of the energy storage battery cell immersion coolant; by adding antioxidants, the contact parts in the liquid-cooled energy storage system can be effectively protected from the influence of oxidative corrosion; by adding corrosion inhibitors, chemical reactions can occur with the metal surface to form a protective film, thereby slowing down the corrosion rate of the metal and reducing equipment damage caused by corrosion, thereby improving the material compatibility of the energy storage battery cell immersion coolant and extending the life of the equipment; by adding inhibitors, the generation of excessive foam during the preparation process of the energy storage battery cell immersion coolant can be alleviated, avoiding the generated foam from affecting the performance of the energy storage battery cell immersion coolant and improving stability.

[0023] In addition, compared with the fluoride used in the prior art, the energy storage battery cell immersion coolant is less volatile and is a more environmentally friendly coolant.

[0024] Furthermore, the base oil is PAO (polyalphaolefin). PAO is a highly efficient fully synthetic base oil with excellent low temperature performance, high viscosity index and antioxidant properties, which can maintain the performance stability of the energy storage battery cell immersion coolant.

[0025] Furthermore, the antioxidant is at least one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, and 2,6-di-tert-butyl-α-dimethylamino-p-cresol.

[0026] Furthermore, the corrosion inhibitor is at least one of diethanolamine, isooctanoic acid, and tolyltriazole.

[0027] Furthermore, the inhibitor is at least one of a benzotriazole derivative and a methylbenzotriazole derivative.

[0028] See also Figure 1 A method for preparing the above-mentioned energy storage battery cell immersion coolant comprises the following steps: S1. Prepare a clean container and make sure it is large enough to hold the required base oil, alkyl naphthalene, antioxidant, corrosion inhibitor and inhibitor, and add the base oil into the container; S2, add alkylnaphthalene into the container and stir evenly; S3, slowly add the corrosion inhibitor into the container and stir evenly; S4, adding an inhibitor and an antioxidant to the container in sequence to obtain a mixed liquid; S5, pouring the mixed liquid in the container into a stirring tank and stirring it evenly.

[0029] From the above, the preparation steps of the immersion coolant for energy storage batteries are relatively simple, have low requirements for equipment configuration, and are easy to prepare.

[0030] More specifically, the stirring time of the stirring tank in step S5 is 30 minutes.

[0031] More specifically, the stirring speed of the stirring tank in step S5 is 110 r / min to 150 r / min.

[0032] More specifically, the humidity during stirring in the stirring tank in step S5 is controlled at 35% to 50%.

[0033] More specifically, the temperature during stirring in the stirring tank in step S5 is controlled at 130° C. to 145° C.

[0034] In order to further illustrate the present invention, the following is a detailed description of an immersion cooling liquid for energy storage batteries and a preparation method thereof provided by the present invention in combination with the examples, but they should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the materials used in the examples and comparative examples can be obtained through commercial channels.

[0035] Embodiment 1: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 83 parts of base oil, 12 parts of alkyl naphthalene, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0036] The preparation method of the immersion coolant for energy storage cells in this embodiment is as follows: add 83 parts of PAO to a container; add 12 parts of alkyl naphthalene to the container and stir evenly; slowly add 2 parts of corrosion inhibitor to the container and stir evenly; add 1 part of inhibitor and 2 parts of antioxidant to the container in sequence; pour the mixed liquid in the container into a stirring tank and stir evenly.

[0037] The stirring time of the stirring kettle is 30 minutes, the stirring speed of the stirring kettle is 110 r / min to 150 r / min, the humidity during stirring in the stirring kettle is controlled at 35% to 50%, and the temperature during stirring in the stirring kettle is controlled at 130°C to 145°C.

[0038] Embodiment 2: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 86 parts of base oil, 9 parts of alkyl naphthalene, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0039] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0040] Embodiment 3: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 89 parts of base oil, 6 parts of alkyl naphthalene, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0041] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0042] Embodiment 4: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 91.5 parts of base oil, 3.5 parts of alkyl naphthalene, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0043] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0044] Embodiment 5: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 86 parts of base oil, 7 parts of alkyl naphthalene, 3 parts of antioxidant, 3 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0045] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0046] Embodiment 6: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 86 parts of base oil, 11 parts of alkyl naphthalene, 1 part of antioxidant, 1 part of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0047] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0048] Comparative Example 1: The energy storage battery cell immersion coolant specifically consists of the following components: by weight, 95 parts of base oil, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0049] The preparation method of the immersion coolant for energy storage cells in this embodiment is as follows: add 95 parts of PAO to a container; slowly add 2 parts of corrosion inhibitor to the container and stir evenly; add 1 part of inhibitor and 2 parts of antioxidant to the container in sequence; pour the mixed liquid in the container into a stirring tank and stir evenly.

[0050] The stirring time of the stirring kettle is 30 minutes, the stirring speed of the stirring kettle is 110 r / min to 150 r / min, the humidity during stirring in the stirring kettle is controlled at 35% to 50%, and the temperature during stirring in the stirring kettle is controlled at 130°C to 145°C.

[0051] Comparative Example 2: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 80 parts of base oil, 15 parts of alkyl naphthalene, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 1 part of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0052] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0053] Comparative Example 3: The difference between the energy storage battery immersion coolant and Example 2 is that API Class II base oil is used instead of PAO.

[0054] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0055] Comparative Example 4: The difference between the energy storage battery immersion coolant and Example 2 is that API Class III base oil is used instead of PAO.

[0056] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0057] Comparative Example 5: The energy storage battery cell immersion coolant is specifically composed of the following components: by weight, 86 parts of base oil, 4 parts of alkyl naphthalene, 4 parts of antioxidant, 4 parts of corrosion inhibitor, and 2 parts of inhibitor. Among them, the base oil is PAO, the antioxidant is 2,6-di-tert-butyl-p-cresol, the corrosion inhibitor is diethanolamine, and the inhibitor is a benzotriazole derivative.

[0058] The preparation method of the energy storage battery cell immersion coolant in this embodiment is the same as the preparation method in Example 1.

[0059] The formulas of the energy storage battery immersion coolants prepared in Examples 1 to 6 and Comparative Examples 1 to 5 of the present invention are shown in Table 1: Table 1

[0060] The test results of the energy storage battery cell immersion coolant prepared in Examples 1 to 6 of the present invention and Comparative Examples 1 to 5 are shown in Table 2: Table 2

[0061] Among them, the test method for kinematic viscosity (40°C) shall be implemented in accordance with the provisions of national standard GB / T 265-2010; the test methods for thermal conductivity and specific heat capacity shall be implemented in accordance with the provisions of national standard GB / T 5990-2021; the test method for pour point shall be implemented in accordance with the provisions of national standard GB / T 3535-2006; the test method for flash point shall be implemented in accordance with the provisions of national standard GB / T 261-2021; the test method for breakdown voltage shall be implemented in accordance with the provisions of national standard GB / T 16927.1-2011.

[0062] From Table 1 and Table 2, we can draw the following conclusions: (1) According to Examples 1 to 6, the kinematic viscosity of the energy storage battery cell immersion coolant of each embodiment of the present invention is in the range of 2 cSt to 15 cSt, which means that the fluidity is good and it can flow and transfer heat more easily in the device, thereby improving the heat conduction efficiency of the energy storage battery cell immersion coolant.

[0063] (2) According to Examples 1 to 6, the thermal conductivity of the energy storage battery cell immersion coolant of each embodiment of the present invention is close to 0.15 W / m·K or greater than 0.15 W / m·K, and the heat conduction efficiency of the energy storage battery cell immersion coolant of the present invention is relatively high.

[0064] (3) According to Examples 1 to 6, the specific heat capacity of the energy storage battery cell immersion coolant of each embodiment of the present invention is close to 2 kJ / kg·K or greater than 2 kJ / kg·K. The specific heat capacity of the energy storage battery cell immersion coolant of the present invention is relatively high, so it can absorb more heat and improve the cooling performance of the energy storage battery cell immersion coolant.

[0065] (4) According to Examples 1 to 6, the flash points of the energy storage battery cell immersion coolant are all ≥160°C and the pour points are all ≤-40°C, indicating that the energy storage battery cell immersion coolant of the present invention has relatively stable performance, and its safety and low-temperature fluidity meet the use requirements.

[0066] (5) According to Examples 1 to 6, the breakdown voltage of the energy storage battery cell immersion coolant is ≥45 kV, indicating that the energy storage battery cell immersion coolant of the present invention can provide safety protection and reduce the risk of electrical failure.

[0067] (6) According to Examples 1, 2, 3, 4 and Comparative Examples 1 and 2, the addition of alkyl naphthalene can reduce the kinematic viscosity (40°C) of the energy storage battery immersion coolant and improve the thermal conductivity. Reducing the kinematic viscosity can improve the fluidity of the energy storage battery immersion coolant, making it easier to flow and transfer heat in the equipment, and improving the thermal conductivity of the energy storage battery immersion coolant can improve its thermal conduction efficiency, so that it can efficiently absorb the heat generated by the energy storage battery. Under the condition that the amount of antioxidants, corrosion inhibitors, and inhibitors added remains unchanged, the content of alkyl naphthalene is not positively correlated with the thermal conductivity of the energy storage battery immersion coolant. Excessive addition of alkyl naphthalene will reduce the performance of the energy storage battery immersion coolant. Although PAO has excellent performance in oxidation stability, excessive addition of alkyl naphthalene changes this balance, resulting in increased viscosity of PAO and reduced low-temperature performance. Therefore, a reasonable amount of alkyl naphthalene added is very important. Among them, Example 2 has the best effect.

[0068] (7) According to Examples 2, 5, 6 and Comparative Example 5, under the condition that the amount of PAO added is unchanged, the total amount of antioxidants, corrosion inhibitors and inhibitors added is not positively correlated with the thermal conductivity of the energy storage battery immersion coolant. Too much added amount will make the antioxidants, corrosion inhibitors and inhibitors unable to be completely dissolved in PAO, which will weaken the cooling effect of the energy storage battery immersion coolant. Among them, Example 2 has the best effect.

[0069] (8) According to Examples 5 and 6, under the condition that the amount of PAO added remains unchanged, the addition of alkyl naphthalene can not only reduce the total amount of antioxidants, corrosion inhibitors, and inhibitors added to the immersion coolant for energy storage batteries, but also maintain the same performance level at the same time.

[0070] (9) According to Example 2 and Comparative Examples 3 and 4, under the condition that the proportions of the components of the energy storage battery immersion coolant are the same, the thermal conductivity effect when the base oil is PAO is much better than the thermal conductivity effect when the base oil is API Class II base oil or API Class III base oil. The thermal conductivity of the energy storage battery immersion coolant depends not only on the formula of the coolant, but more importantly on the performance of the base oil. Among them, Example 2 has the best effect.

[0071] The advantages of the energy storage battery cell immersion coolant provided by the embodiment of the present invention include: (1) High thermal conductivity and high specific heat capacity.

[0072] (2) Promote the dissolution of additives in base oil and improve the utilization rate of additives.

[0073] (3) Reduce the risk of equipment corrosion and extend the service life of equipment.

[0074] (4) Safe and environmentally friendly.

[0075] (5) Stable performance.

[0076] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A battery cell immersion coolant for energy storage, characterized in that: The energy storage battery immersion coolant consists of the following components in parts by weight: 83-95 parts of base oil, 3.5-12 parts of alkyl naphthalene, 0.5-3 parts of antioxidant, 0.5-3 parts of corrosion inhibitor, and 0.5-1 part of inhibitor.

2. The energy storage battery cell immersion coolant according to claim 1, characterized in that: The base oil is PAO (polyalphaolefin).

3. The energy storage battery cell immersion coolant according to claim 1, characterized in that: The antioxidant is at least one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-α-dimethylamino-p-cresol.

4. The energy storage battery cell immersion coolant according to claim 1, characterized in that: The corrosion inhibitor is at least one of diethanolamine, isooctanoic acid and toluene triazole.

5. The energy storage battery cell immersion coolant according to claim 1, characterized in that: The inhibitor is at least one of a benzotriazole derivative and a methylbenzotriazole derivative.

6. A method for preparing the energy storage battery core immersion coolant according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, adding the base oil into a container; S2, adding the alkylnaphthalene into the container and stirring evenly; S3, slowly adding the corrosion inhibitor into the container and stirring evenly; S4, adding the inhibitor and the antioxidant into the container in sequence; S5, pouring the mixed liquid in the container into a stirring tank and stirring it evenly.

7. The energy storage battery cell immersion coolant according to claim 6, characterized in that: The stirring time of the stirring tank in step S5 is 30 min.

8. The energy storage battery cell immersion coolant as claimed in claim 6, characterized in that: The stirring speed of the stirring kettle in step S5 is 110 r / min to 150 r / min.

9. The energy storage battery cell immersion coolant according to claim 6, characterized in that: The humidity during stirring in the stirring tank in step S5 is controlled at 35% to 50%.

10. The energy storage battery cell immersion coolant according to claim 6, characterized in that: The temperature during stirring in the stirring tank in step S5 is controlled at 130° C. to 145° C.

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