Cooling liquid in direct contact with battery cell and preparation method of cooling liquid

Abstract

The invention relates to a cooling liquid for direct contact of battery cells and a preparation method thereof, the cooling liquid for direct contact of battery cells comprises the following raw materials by weight: 60-100 parts of a basic solvent, 10-30 parts of an auxiliary solvent, 0.01-1 part of a high temperature additive, 0.01-1 part of an antioxidant, 0.01-1 part of an anti-wear additive, 0.01-1 part of an antifoaming agent, and 0.01-1 part of an auxiliary heat conduction agent. The cooling liquid can be in direct contact with a battery, is not easy to volatilize and is low in cost, heat generated in the charging and discharging process of a battery cell is taken away through direct contact with the battery cell, the uniformity degree of the temperature of the battery cell is greatly improved, and the cooling liquid has good compatibility with the surface of the battery cell, is not corroded, is not easy to volatilize and is low in cost; the cooling liquid is expected to become a cooling liquid of a new generation of thermal management products

Description

Technical Field

[0001] The present invention relates to the technical field of battery cell coolants, and particularly to a coolant in direct contact with battery cells and a preparation method thereof. Background Art

[0002] As a core component of electrochemical energy storage, a battery has a relatively high risk of thermal runaway. When thermal runaway occurs, a large amount of heat will be released instantaneously and spread rapidly to adjacent batteries, triggering large-scale thermal runaway of the battery pack and causing serious fire or explosion accidents. From the perspective of safety, it is very important to do a good job in the thermal management of the energy storage system, especially the thermal management of the battery system, to effectively control and solve the fire and explosion risks brought by thermal runaway.

[0003] At present, the battery thermal management technologies in energy storage systems mainly include air cooling or cold plate liquid cooling. Among them, air cooling uses natural wind pressure or an air conditioning system to dissipate heat from the battery. Although it has a simple structure and is easy to install, its cooling efficiency is not high, the battery heat dissipation is uneven, and the temperature difference between battery packs is relatively large (4°C - 8°C); cold plate liquid cooling places a cooling plate filled with circulating coolant under the battery cell to cool the contact part of the battery cell, and the coolant does not directly contact the battery cell, which is an indirect cooling method and has deficiencies such as slow cooling speed and long time. Moreover, both cooling methods are insufficient in directly reducing the battery cell temperature and reducing the difference in the operating temperature of battery cells.

[0004] Immersion liquid-cooled battery energy storage is to directly immerse the energy storage battery in the coolant, the battery cell is in direct contact with the coolant, and is completely isolated from oxygen, realizing direct, rapid, and sufficient cooling and temperature reduction of the battery, ensuring that the battery operates within the optimal temperature range, effectively extending the service life of the battery, and overall improving the safety performance of the energy storage power station.

[0005] In the existing technology, such as the Chinese patent with the publication number CN110055037A, it discloses an immersion cooling coolant for power lithium batteries and a preparation method thereof, which relates to the chemical engineering field. It is composed of the following formula with weight ratios: 30 parts - 70 parts of hydrofluoroether compounds, 30 parts - 50 parts of halogenated hydrocarbons, 1 part - 10 parts of alcohol compounds, 0.01 part - 0.5 part of antioxidant, 0.01 part - 0.5 part of preservative, and 0.01 part - 0.5 part of nano metal oxide. The present invention mainly uses hydrofluoroether compounds, forms an azeotrope by mixing with halogenated hydrocarbons, alcohol compounds, etc., and is supplemented with antioxidant, preservative, and non-conductive nano metal oxide additive to form a coolant composition.

[0006] The existing technical solutions described above have the following defects: The coolant mentioned above is a hydrofluoroether compound that can directly soak lithium batteries. Although it has excellent environmental performance, good safety performance, and low surface tension, and is particularly suitable for heat conduction applications in precision instruments and the electronics industry, the price of hydrofluoroether coolants is relatively high, the density is relatively high, and they are prone to volatilization, making them unsuitable for large-scale low-cost energy storage applications. Summary of the Invention

[0007] In view of the deficiencies of the existing technology, the object of the present invention is to provide a coolant for direct contact with the battery core and its preparation method. It is a coolant that can be in direct contact with the battery, is not prone to volatilization, and has a relatively low cost. By directly contacting the battery core, it takes away the heat generated during the charging and discharging process of the battery core, greatly improving the uniformity of the battery core temperature. Moreover, the coolant has good compatibility with the surface of the battery core, no corrosion, is not prone to volatilization, and has a low cost, and is expected to become a coolant for a new generation of thermal management products.

[0008] The above object of the present invention is achieved through the following technical solutions:

[0009] A coolant for direct contact with the battery core, comprising the following raw materials by weight: 60 parts - 100 parts of a base solvent, 10 - 30 parts of an auxiliary solvent, 0.01 parts - 1 part of a high-temperature additive, 0.01 parts - 1 part of an antioxidant, 0.01 parts - 1 part of an anti-wear additive, 0.01 parts - 1 part of an antifoaming agent, 0.01 parts - 1 part of an auxiliary heat-conducting agent.

[0010] As a further technical solution of the present invention: It comprises the following raw materials by weight: 80 parts of a base solvent, 20 parts of an auxiliary solvent, 0.01 parts - 1 part of a high-temperature additive, 0.01 parts - 1 part of an antioxidant, 0.01 parts - 1 part of an anti-wear additive, 0.01 parts - 1 part of an antifoaming agent, 0.01 parts - 1 part of an auxiliary heat-conducting agent.

[0011] As a further technical solution of the present invention: The base solvent is one of n-octadecane, n-nonadecane, and n-eicosane.

[0012] As a further technical solution of the present invention: The auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane.

[0013] As a further technical solution of the present invention: The high-temperature additive is one of biphenyl, thiophene, and furan.

[0014] As a further technical solution of the present invention: The antioxidant is one of diphenylamine and phenylenediamine.

[0015] As a further technical solution of the present invention: The anti-wear additive is sodium borate.

[0016] As a further technical solution of the present invention: the defoaming agent is sodium dodecylbenzenesulfonate.

[0017] As a further technical solution of the present invention: the auxiliary heat-conducting agent is silicon carbide nanoparticles.

[0018] A preparation method of a coolant in direct contact with an electric core as described above includes the following steps:

[0019] Step 1: Add a certain amount of basic solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank controlled at about 60°C;

[0020] Step 2: Start stirring, and add appropriate proportions of auxiliary heat-conducting agent, defoaming agent, anti-wear additive, antioxidant, high-temperature additive, auxiliary solvent in sequence while stirring, and add the next substance every 2 hours;

[0021] Step 3: Stir at a high speed of 2500 revolutions per minute for 50 minutes to obtain the coolant in direct contact with the electric core;

[0022] Step 4: Pour the finished product liquid of the coolant in direct contact with the electric core prepared in Step 3 into a plastic bucket and seal it for storage.

[0023] In summary, the present invention includes at least one of the following beneficial technical effects:

[0024] The present invention discloses a coolant in direct contact with an electric core and a preparation method thereof. The raw materials used are simple and easy to obtain, and the cost is relatively low. Moreover, it has good heat-conducting effect in direct contact with the electric core, and has characteristics such as non-volatility, non-corrosion, and non-flammability. When applied in the cooling system of a battery pack, it can ensure that the temperature of the electric cores in the battery pack is uniform. During long-term operation, the coolant does not deteriorate and does not need to be replaced with oil for life. By directly contacting the electric core, the heat generated during the charging and discharging process of the electric core is taken away, greatly improving the uniformity of the electric core temperature. And the coolant has good compatibility with the surface of the electric core, no corrosion, is not easy to volatilize, and has low cost, and is expected to become a coolant for a new generation of thermal management products. Specific Embodiments

[0025] Next, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application; obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0026] Example 1:

[0027] A coolant for direct contact with an electric cell, comprising the following raw materials by weight: 60 parts - 100 parts of a base solvent, 10 - 30 parts of an auxiliary solvent, 0.01 part - 1 part of a high-temperature additive, 0.01 part - 1 part of an antioxidant, 0.01 part - 1 part of an anti-wear additive, 0.01 part - 1 part of an antifoaming agent, 0.01 part - 1 part of an auxiliary heat-conducting agent.

[0028] The base solvent is one of n-octadecane, n-nonadecane, and n-eicosane. The auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane. The high-temperature additive is one of biphenyl, thiophene, and furan. The antioxidant is one of diphenylamine and phenylenediamine. The anti-wear additive is sodium borate. The antifoaming agent is sodium dodecylbenzenesulfonate. The auxiliary heat-conducting agent is silicon carbide nanoparticles.

[0029] A preparation method of a coolant for direct contact with an electric cell as described above, comprising the following steps:

[0030] Step 1: Add a certain amount of the base solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank controlled at about 60 °C;

[0031] Step 2: Start stirring, and add the appropriate proportions of the auxiliary heat-conducting agent, antifoaming agent, anti-wear additive, antioxidant, high-temperature additive, and auxiliary solvent in sequence while stirring. Add the next substance every 2 h;

[0032] Step 3: Stir at a high speed of 2500 revolutions per minute for 50 minutes to obtain the coolant for direct contact with the electric cell;

[0033] Step 4: Pour the finished product liquid of the coolant for direct contact with the electric cell prepared in Step 3 into a plastic bucket and seal it for storage.

[0034] Example 2:

[0035] A coolant for direct contact with an electric cell, comprising the following raw materials by weight: 80 parts of a base solvent, 20 parts of an auxiliary solvent, 0.51 part of a high-temperature additive, 0.51 part of an antioxidant, 0.50 part of an anti-wear additive, 0.50 part of an antifoaming agent, 0.50 part of an auxiliary heat-conducting agent.

[0036] The base solvent is n-octadecane, the auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane. The high-temperature additive is biphenyl, the antioxidant is diphenylamine, the anti-wear additive is sodium borate, the antifoaming agent is sodium dodecylbenzenesulfonate, and the auxiliary heat-conducting agent is silicon carbide nanoparticles.

[0037] A preparation method of a coolant for direct contact with an electric cell as described above, comprising the following steps:

[0038] Step 1: Add a certain amount of base solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank controlled at about 60°C;

[0039] Step 2: Turn on the stirring, and while stirring, add appropriate proportions of auxiliary heat-conducting agent, defoaming agent, anti-wear additive, antioxidant, high-temperature additive, auxiliary solvent in sequence, and add the next substance every 2 hours;

[0040] Step 3: Stir at a high speed of 2500 revolutions per minute for 50 minutes to obtain the coolant in direct contact with the battery cell;

[0041] Step 4: Pour the finished product of the coolant in direct contact with the battery cell prepared in Step 3 into a plastic bucket and seal it for storage.

[0042] Example 3:

[0043] A coolant in direct contact with a battery cell includes the following raw materials by weight: 80 parts of base solvent, 20 parts of auxiliary solvent, 0.51 part of high-temperature additive, 0.51 part of antioxidant, 0.50 part of anti-wear additive, 0.50 part of defoaming agent, 0.50 part of auxiliary heat-conducting agent.

[0044] The base solvent is n-nonadecane, and the auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane. The high-temperature additive is thiophene, the antioxidant is phenylenediamine, the anti-wear additive is sodium borate, the defoaming agent is sodium dodecylbenzenesulfonate, and the auxiliary heat-conducting agent is silicon carbide nanoparticles.

[0045] The preparation method of a coolant in direct contact with a battery cell as described above includes the following steps:

[0046] Step 1: Add a certain amount of base solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank controlled at about 60°C;

[0047] Step 2: Turn on the stirring, and while stirring, add appropriate proportions of auxiliary heat-conducting agent, defoaming agent, anti-wear additive, antioxidant, high-temperature additive, auxiliary solvent in sequence, and add the next substance every 2 hours;

[0048] Step 3: Stir at a high speed of 2500 revolutions per minute for 50 minutes to obtain the coolant in direct contact with the battery cell;

[0049] Step 4: Pour the finished product of the coolant in direct contact with the battery cell prepared in Step 3 into a plastic bucket and seal it for storage.

[0050] Example 4:

[0051] A coolant for direct contact with an electric cell, comprising the following raw materials by weight: 80 parts of a base solvent, 20 parts of an auxiliary solvent, 0.51 part of a high-temperature additive, 0.51 part of an antioxidant, 0.50 part of an antiwear additive, 0.50 part of an antifoaming agent, and 0.50 part of an auxiliary heat-conducting agent.

[0052] The base solvent is n-eicosane, the auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane, the high-temperature additive is furan, the antioxidant is phenylenediamine, the antiwear additive is sodium borate, the antifoaming agent is sodium dodecylbenzenesulfonate, and the auxiliary heat-conducting agent is silicon carbide nanoparticles.

[0053] A preparation method of the coolant for direct contact with an electric cell as described above, comprising the following steps:

[0054] Step 1: Add a certain amount of the base solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank controlled at about 60 °C;

[0055] Step 2: Start stirring, and sequentially add appropriate proportions of the auxiliary heat-conducting agent, antifoaming agent, antiwear additive, antioxidant, high-temperature additive, and auxiliary solvent while stirring, and add the next substance every 2 h;

[0056] Step 3: Stir at a high speed of 2500 revolutions per minute for 50 minutes to obtain the coolant for direct contact with an electric cell;

[0057] Step 4: Pour the finished product liquid of the coolant for direct contact with an electric cell prepared in Step 3 into a plastic bucket and seal it for storage.

[0058] The implementation principle of the present invention is as follows: The present invention discloses a coolant for direct contact with an electric cell and its preparation method. The raw materials used are simple and easy to obtain, with low cost, and have good heat-conducting effect when in direct contact with the electric cell, and also have characteristics such as non-volatility, non-corrosion, and non-flammability. When applied in the cooling system of a battery pack, it can ensure that the temperature of the electric cells in the battery pack is uniform. During long-term operation, the coolant does not deteriorate and does not need to be changed for life. By directly contacting the electric cell, the heat generated during the charge and discharge process of the electric cell is taken away, greatly improving the uniformity of the electric cell temperature. And the coolant has good compatibility with the surface of the electric cell, no corrosion, is not easy to volatilize, and has low cost, and is expected to become a coolant for a new generation of thermal management products.

[0059] The coolants for direct contact with an electric cell prepared in Examples 2, 3, and 4 are tested with Comparative Document 1 in the background art and other existing coolants. The main test indexes are compared as follows:

[0060] Thermal conductivity detection: After heating the same mass of the coolant to 100 °C, under magnetic stirring at 30 revolutions per minute, the temperature is reduced in a 25 °C air environment. The performance is as follows:

[0061] Table 1

[0062]

[0063]

[0064] Table 2

[0065] Item Unit Performance Method Density (25°C) <![CDATA[g / cm 3 > 0.7899 GB / T1884 Kinematic viscosity (40°C) <![CDATA[mm 2 / s]]> 9.34 GB / T265 Pour point ℃ -45 GB / T3535 Flash point ℃ 279.6 GB / T3536 Specific heat capacity (40°C) J / g.K 2.301 Laboratory DSC method Breakdown voltage KV 38.1 GB / T507 Dielectric constant 2.103 GB / T5654

[0066] As can be seen from Table 1 and Table 2, the coolant in direct contact with the battery cells prepared by the present invention uses raw materials that are simple to obtain and have low costs. Moreover, it has good heat transfer effects in direct contact with the battery cells, fast cooling speeds, and characteristics such as non-volatility, non-corrosion, and non-flammability. When applied in the cooling system of a battery pack, it can ensure that the temperatures of the battery cells in the battery pack are uniform, the coolant does not deteriorate during long-term operation, and the oil does not need to be changed throughout its service life.

[0067] The embodiments of this specific implementation manner are all preferred embodiments of the present invention and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A coolant directly contacted by a battery cell, characterized in that: The invention comprises the following raw materials in parts by weight: 60-100 parts of basic solvent, 10-30 parts of auxiliary solvent, 0.01-1 part of high temperature additive, 0.01-1 part of antioxidant, 0.01-1 part of anti-wear additive, 0.01-1 part of defoaming agent and 0.01-1 part of auxiliary thermal conductive agent.

2. The coolant directly contacting the battery core according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 80 parts of basic solvent, 20 parts of auxiliary solvent, 0.01-1 part of high temperature additive, 0.01-1 part of antioxidant, 0.01-1 part of anti-wear additive, 0.01-1 part of defoaming agent, and 0.01-1 part of auxiliary thermal conductive agent.

3. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The base solvent is one of n-octadecane, n-nonadecane and n-eicosane.

4. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The auxiliary solvent is 1,1,1,2,3,4,4,5,5,5-decafluoropentane.

5. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The high temperature additive is one of biphenyl, thiophene and furan.

6. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The antioxidant is diphenylamine, one of phenylenediamine.

7. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The anti-wear additive is sodium borate.

8. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The defoamer is sodium dodecylbenzene sulfonate.

9. A coolant for direct contact with a battery cell according to any one of claims 1 or 2, characterized in that: The auxiliary thermal conductor is silicon carbide nanoparticles.

10. A method for preparing a coolant for direct contact with a battery cell according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Add a certain amount of base solvent into a blending tank equipped with a stirring device, and keep the temperature of the blending tank at about 60°C; Step 2, start stirring, add auxiliary thermal conductive agent, defoaming agent, anti-wear additive, antioxidant, high temperature additive, auxiliary solvent in appropriate proportions in sequence while stirring, and add the next substance every 2 hours; Step 3, stirring at a high speed of 2500 rpm for 50 minutes to obtain a coolant that directly contacts the battery core; Step 4: Put the finished coolant liquid directly in contact with the battery cell obtained in step 3 into a plastic barrel and seal it for storage.

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