A static immersion cooling system with 50% ethylene glycol and water as the cooling medium

Abstract

The application discloses a static immersion cooling system with 50% ethylene glycol and water as cooling medium, comprising a liquid cooling unit, a liquid inlet pipe, a liquid return pipe and a plurality of static immersion battery boxes; the static immersion battery box is based on directly immersing the battery cell module in the immersion liquid, so that the heat source battery cell, aluminum row and the like are directly and fully contacted with the immersion liquid, heat dissipation is more uniform and efficient, the temperature gradient of the battery can be effectively reduced, and the local overheating phenomenon is reduced; the main heat dissipation mode is that heat is conducted to synthetic oil through the battery cell aluminum row and the like, and then the heat is taken away through the internal cooling channel; the cooling medium of the system is 50% ethylene glycol and water, the internal pump and the compressor of the unit are utilized to heat or cool the cooling medium and provide circulating power; compared with the circulating flow of the traditional immersion liquid itself, the medium of 50% ethylene glycol and water has low viscosity and small flow resistance, the shortcoming that the immersion liquid is difficult to circulate due to the large viscosity can be avoided, and the power consumption of the required external cooling unit is low.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management, specifically a static immersion cooling system using 50% ethylene glycol and water as the cooling medium. Background Technology

[0002] Battery modules generate heat during charging and discharging. Excessive temperature and uneven localized temperature distribution within the battery can severely reduce battery life. Therefore, the heat dissipation performance of the battery module is a crucial factor affecting battery performance, efficiency, lifespan, and safety. Currently, existing liquid-cooled battery pack structures use cooling channels at the bottom for heat dissipation. However, the heat-generating parts of the battery cells are primarily the terminals. This results in uneven cell temperatures, significantly reducing the battery's operating temperature range and the overall energy efficiency of the battery pack, shortening battery life, and potentially posing safety hazards.

[0003] The existing battery box has uneven temperature distribution of modules, with localized overheating, which is not conducive to the long-term use of the battery system and cannot guarantee safety and reliability.

[0004] The battery box has low cooling efficiency, resulting in a small operating temperature range for the battery.

[0005] The liquid-cooled battery boxes used in the market only dissipate heat through bottom liquid cooling. The temperature of the cell terminals and aluminum busbars is still too high and they are the main heat sources, resulting in a large temperature difference in the overall battery box.

[0006] Therefore, it is necessary to improve such a structure to overcome the above-mentioned defects. Summary of the Invention

[0007] The purpose of this invention is to provide a static immersion cooling system using 50% ethylene glycol and water as the cooling medium to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A static immersion cooling system using 50% ethylene glycol and water as the cooling medium includes a liquid cooler unit, an inlet pipe, a return pipe, and several static immersion battery boxes.

[0010] The static immersion battery box is a sealed box that contains battery cell modules and an immersion medium, which is an immersion liquid. The battery cell modules are immersed in the immersion liquid. The static immersion battery box is equipped with a cooling channel.

[0011] The liquid chiller unit stores a cooling medium, which is a mixture of ethylene glycol and water at a volume ratio of 50%. The liquid chiller unit, the inlet pipe, the cooling channel, and the return pipe are connected in sequence to form an external circulation loop. The liquid chiller unit is configured to drive the cooling medium to circulate and regulate its temperature so as to exchange heat with the immersion liquid through the cooling channel.

[0012] Furthermore, several of the static immersion battery boxes are stacked vertically, and the cooling channels of each static immersion battery box are sequentially connected in parallel between the liquid inlet pipe and the liquid return pipe.

[0013] Furthermore, the liquid cooling unit includes a compressor, a pump, and a temperature control unit. The pump is configured to provide circulating power for the cooling medium, and the compressor is configured to regulate the cooling medium by cooling or heating it.

[0014] Furthermore, the cooling channel is located at the bottom, side, or top of the static immersion battery box, or a combination of any two or three of these locations.

[0015] Furthermore, no booster pump for circulating the immersion liquid is provided in the external circulation loop, and the immersion liquid is in a static immersion state in the static immersion battery box.

[0016] A battery thermal management method employs the aforementioned static immersion battery cooling system, which completely immerses the battery cell module in an immersion liquid within a sealed battery case, allowing the heat generated by the battery cell module during operation to be directly transferred to the immersion liquid.

[0017] A liquid cooling unit drives a mixture of 50% ethylene glycol and water as the cooling medium, which circulates in the external circulation loop. The cooling medium flows through the cooling channels inside the battery box to exchange heat indirectly with the immersion liquid, thereby removing the heat generated by the battery cell module.

[0018] Furthermore, the viscosity of the cooling medium is lower than that of the immersion liquid.

[0019] Furthermore, the static immersion cooling system using 50% ethylene glycol and water as the cooling medium is applied to the thermal management of batteries in energy storage power stations.

[0020] Furthermore, the static immersion cooling system using 50% ethylene glycol and water as the cooling medium is applied to the thermal management of electric vehicle power batteries.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] Compared to the traditional circulating flow of the immersion fluid, the medium of 50% ethylene glycol and water has low viscosity and low flow resistance. This not only avoids the disadvantage of immersion fluids being difficult to circulate due to their high viscosity, but also reduces the power consumption of the external cooling unit required. Furthermore, it solves the problem of oil leakage caused by the complex circulation path of the immersion fluid. Compared to traditional liquid cooling, it reduces the excessive temperature difference between the hot front and cold rear of the battery cells, and is more cost-effective and reliable than cooling with dynamic oil circulation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a static immersion cooling system using 50% ethylene glycol and water as the cooling medium.

[0024] Figure 2 This is a front view of a static immersion cooling system using 50% ethylene glycol and water as the cooling medium.

[0025] Figure 3 This is a side view of a static immersion cooling system using 50% ethylene glycol and water as the cooling medium.

[0026] Figure 4 This is a top view of a static immersion cooling system using 50% ethylene glycol and water as the cooling medium.

[0027] Figure 5 This is a schematic diagram of the internal structure of a statically submerged battery box in a statically submerged cooling system that uses 50% ethylene glycol and water as the cooling medium (the battery cells and other structures are omitted from the top of the box in the diagram). Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] like Figure 1-5 As shown in Example 1, a static immersion cooling system using 50% ethylene glycol and water as the cooling medium includes a liquid cooler unit 100, an inlet pipe 200, a return pipe 300, and five static immersion battery boxes 400 arranged vertically.

[0030] In this design, the static immersion battery box 400 measures 1060mm × 630mm × 240mm. The box body is made of sheet metal welding, casting, or plastic injection molding. It is internally sealed and contains built-in battery cell modules. The static immersion battery box 400 is filled with an immersion fluid.

[0031] The immersion fluid used is commercially available AP-5 type single-phase dielectric silicone oil coolant, with the amount of fluid injected enough to completely submerge the battery cell terminals and aluminum busbars; its flash point is >200℃, breakdown voltage (2.5mm gap) is 19–52kV, specific heat capacity is approximately 1.85 kJ / (kg·K) (40℃), kinematic viscosity is 10±1cSt (25℃), and volume resistivity is >1×10¹ 4 The Ω·cm value meets the requirements for static immersion heat transfer and insulation safety of energy storage batteries. In other embodiments, modified silicone oil, synthetic ester, or fluorinated liquid with a flash point ≥180℃ and breakdown voltage ≥25kV / 2.5mm can also be used; various immersion liquids such as transformer oil can also be used.

[0032] The internal cooling channel 401 uses a stainless steel serpentine coil, which is attached to the inner surface of the top of the box. The inlet and outlet are connected to the external pipeline through the side wall flange of the box. The capacity of the stainless steel serpentine coil is 1.2L.

[0033] The liquid cooling unit 100 incorporates: a variable frequency magnetic drive pump and a refrigeration compressor.

[0034] A 50% volume ratio ethylene glycol + water mixture is used as the primary cooling medium, with a total charge of 40L.

[0035] After the external circulating medium flows out of the liquid cooler unit 100, it enters the top coil of the battery box through the inlet pipe 200, flows through the entire top coil of the battery box, and then returns to the liquid cooler unit 100 through the return pipe 300.

[0036] Example 2: The difference between this example and Example 1 is that the cooling channel 401 is only arranged on the bottom inner surface of the static immersion battery box 400, and is made of aluminum alloy stamped cold plate. The internal flow channel of the cold plate is a parallel direct flow channel with a width of 4mm and a depth of 3mm. A total of 24 flow channels are arranged in parallel, and the channel volume of a single box is 0.8L.

[0037] The external circulating medium flows out of the liquid chiller 100 and enters the top cold plate through the liquid inlet pipe 200. After flowing through the entire cold plate, it returns to the liquid chiller 100 through the liquid return pipe 300.

[0038] Example 3 differs from Example 1 in that the cooling channel 401 adopts a side spiral tube structure, that is, it is arranged in a spiral around the inner side of the four side walls of the static immersion battery box 400, and is made of bent copper tube. The capacity of the side spiral tube is 1.5L.

[0039] After the external circulating medium flows out of the liquid chiller 100, it enters the side spiral tube through the inlet pipe 200, flows upward along the spiral path, and returns to the liquid chiller 100 through the return pipe 300 after exiting from the top outlet.

[0040] Example 4 differs from Example 1 in that:

[0041] Cooling channel 401 adopts a dual layout of "top coil (Example 1) + bottom aluminum alloy stamped cold plate (Example 2)".

[0042] After the external circulating medium flows out of the liquid chiller 100, it passes through the top coil and the bottom aluminum alloy stamped cold plate, and finally returns to the liquid chiller 100 through the return pipe 300.

[0043] Example 5 differs from Example 1 in that:

[0044] The cooling channel 401 adopts "top coil (Example 1) + side spiral tube (Example 3)" and is arranged at the bottom and inside the four side walls of the static immersion battery box 400. The bottom and side wall channels are connected in parallel outside the box (each is equipped with an independent regulating valve).

[0045] After the external circulating medium flows out of the liquid chiller 100, it passes through the top coil and the side spiral tube, and finally returns to the liquid chiller 100 through the return pipe 300.

[0046] Example 6 differs from Example 1 in that:

[0047] The cooling channel 401 adopts "top coil (Example 1) + bottom aluminum alloy stamped cold plate (Example 2) + side spiral tube (Example 3)".

[0048] After the external circulating medium flows out of the liquid chiller 100, it passes through the top coil, the bottom aluminum alloy stamped cold plate and the side spiral tube, and finally returns to the liquid chiller 100 through the return pipe 300.

[0049] It is worth noting that in all embodiments of the scheme, the liquid-cooled unit 100 integrates a variable frequency magnetic drive pump and a refrigeration compressor. The pump operating power is constant at 120W, the compressor operating power is constant at 1880W, and the total system power consumption is constant at 2.0kW. The only difference between the embodiments is the arrangement of the cooling channel 401 inside the static submerged battery box 400. The external circulation flow rate, medium temperature, and unit operating power are all kept consistent to eliminate power-side variable interference. The operating conditions of each embodiment are shown in Table 1 below (ambient temperature 25℃, pump 120W constant, compressor unit 1880W constant, total 2.0kW constant).

[0050] Example Immersion liquid temperature equalization Maximum / Minimum Temperature of Battery Cell (Temperature Difference) Total power consumption 1 28.9℃ 29.8 / 28.3 (1.5℃) 2.0kW 2 29.6℃ 30.5 / 29.0 (1.5℃) 2.0kW 3 29.3℃ 30.2 / 28.7 (1.5℃) 2.0kW 4 28.7℃ 29.5 / 28.4 (1.1℃) 2.0kW 5 28.9℃ 29.7 / 28.6 (1.1℃) 2.0kW 6 28.6℃ 29.4 / 28.4 (1.0℃) 2.0kW

[0051] Table 1

[0052] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connect" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

Claims

1. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium, characterized in that, Includes liquid cooling unit, liquid inlet pipe, liquid return pipe, and several static submersible battery boxes; The static immersion battery box is a sealed box that contains battery cell modules and an immersion medium, which is an immersion liquid. The battery cell modules are immersed in the immersion liquid. The static immersion battery box is equipped with a cooling channel. The liquid chiller unit stores a cooling medium, which is a mixture of ethylene glycol and water at a volume ratio of 50%. The liquid chiller unit, the inlet pipe, the cooling channel, and the return pipe are connected in sequence to form an external circulation loop. The liquid chiller unit is configured to drive the cooling medium to circulate and regulate its temperature so as to exchange heat with the immersion liquid through the cooling channel.

2. The static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to claim 1, characterized in that, Several static immersion battery boxes are stacked vertically, and the cooling channels of each static immersion battery box are connected in parallel between the liquid inlet pipe and the liquid return pipe.

3. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to claim 1, characterized in that, The liquid cooling unit includes a compressor, a pump, and a temperature control unit. The pump is configured to provide circulating power for the cooling medium, and the compressor is configured to regulate the temperature of the cooling medium by cooling or heating.

4. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to claim 1, characterized in that, The cooling channel is located at the bottom, side, or top of the static immersion battery box, or a combination of any two or three of these channels.

5. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to claim 1, characterized in that, No booster pump for circulating the immersion liquid is provided in the external circulation loop, and the immersion liquid is in a static immersion state in the static immersion battery box.

6. A battery thermal management method, characterized in that, The static immersion battery cooling system as described in any one of claims 1-5 is used to completely immerse the battery cell module in the immersion liquid inside the sealed battery box, so that the heat generated by the battery cell module during operation is directly transferred to the immersion liquid. A mixture of 50% ethylene glycol and water is used as the cooling medium by a liquid chiller unit to circulate in the external circulation loop. The cooling medium flows through the cooling channel inside the battery box to indirectly exchange heat with the immersion liquid, thereby removing the heat generated by the battery cell module.

7. A battery thermal management method according to claim 6, characterized in that, The viscosity of the cooling medium is lower than that of the immersion liquid.

8. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to any one of claims 1-5, characterized in that, The system is used for battery thermal management in energy storage power stations.

9. A static immersion cooling system using 50% ethylene glycol and water as the cooling medium according to any one of claims 1-5, characterized in that, The system is used for thermal management of electric vehicle power batteries.

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