Refrigerating system and refrigerating method of high-capacity battery pack

Abstract

The invention discloses a refrigeration system and a refrigeration method of a high-capacity battery pack, the system comprises a battery compartment and a cooling liquid filled in the battery compartment, a frame body immersed in the cooling liquid is mounted in the battery compartment, a plurality of layers of battery cell groups are arranged on the frame body, and each layer of battery cell group is provided with a plurality of battery cells directly contacted with the cooling liquid; wherein an evaporation copper pipe wound on the frame body is further arranged in the battery bin, the evaporation copper pipe is communicated with a refrigeration device located outside the battery bin, and the refrigeration device and the evaporation copper pipe are filled with refrigerants, so that heat in the cooling liquid is transferred to the outside of the battery bin through evaporation heat absorption of the refrigerants in the evaporation copper pipe and liquidation heat release of the refrigerants in the refrigeration device. According to the present invention, by using the characteristics of the phase change of the refrigerant in the evaporation copper pipe and the large specific heat capacity and the high heat exchange coefficient of the cooling liquid, the heat of the battery cells can be rapidly taken away, the heat dissipation efficiency can be improved, the uniform temperature effect of each battery cell can be ensured, the high-power liquid cooling unit does not need to be adopted, and the energy consumption can be substantially reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery refrigeration, and in particular relates to a refrigeration system and a refrigeration method for a large-capacity battery pack. Background Art

[0002] At present, the main cooling methods for battery systems include air cooling, cold plate liquid cooling, cold plate direct cooling and immersion liquid cooling;

[0003] For example, the air cooling system uses a refrigerator to blow away the heat from the battery cell. Its advantages are simple structure and low cost, but the heat dissipation effect is poor, and the heat dissipation effect is even worse when the ambient temperature is high.

[0004] For example, cold plate liquid cooling uses direct contact between the battery cell and a cold plate filled with liquid. The heat of the battery cell is transferred to the liquid inside the cold plate through the cold plate, and the heat is taken away by liquid circulation. Its advantage is that the thermal conductivity of liquid is much higher than that of air, and the heat dissipation effect of liquid cooling is better than that of air cooling. However, there is a large temperature difference between the upper and lower parts of the same battery cell, and the liquid cooling system has a complex structure and high cost.

[0005] For example, in cold plate direct cooling, the refrigerant absorbs heat by vaporizing the fluorine cold plate installed at the bottom of the battery cell, and quickly takes away the heat from the bottom of the battery cell. The advantage is that the heat dissipation rate is very high, but the temperature difference between the upper and lower parts of the same battery cell will increase, affecting the life of the battery cell.

[0006] Immersion liquid cooling is to immerse the battery cells directly in the coolant and remove the heat through the circulation of the coolant. Its advantage is that the battery cells are directly immersed in the insulating and heat-conductive coolant, and the high heat transfer coefficient and large specific heat capacity of the liquid are utilized to achieve good heat dissipation effect. At the same time, since the battery cells are immersed in the coolant, the temperature equalization effect of the battery cells is also good. However, for large-capacity battery cells or high-rate discharge occasions, the large amount of heat generated by the battery cells cannot be transferred out in time, which will cause a large temperature difference in the battery cells. If a high-power liquid cooling unit is used, it will cause high energy consumption and high cost of the system. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a refrigeration system and a refrigeration method for a large-capacity battery pack, which are suitable for refrigeration operations of large-capacity battery packs. The system and a refrigeration method utilize the phase change of the refrigerant inside the evaporating copper tube and the large specific heat capacity and high heat transfer coefficient of the coolant to quickly take away the heat of the battery cell and improve the heat dissipation efficiency while ensuring the uniform temperature effect of each battery cell. There is no need to use a high-power liquid cooling unit or a circulating water pump, which greatly reduces energy consumption. There is no need to design a battery pack with IP67 or even higher protection requirements, and the design is simple and the cost is low.

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

[0009] A cooling system for a large-capacity battery pack, comprising a battery compartment and a coolant filled in the battery compartment, wherein a frame immersed in the coolant is installed in the battery compartment, and a plurality of layers of battery cell groups are arranged on the frame, wherein each layer of the battery cell group has a plurality of battery cells directly in contact with the coolant;

[0010] The battery compartment is also provided with an evaporating copper tube coiled on the frame, the evaporating copper tube is connected to a refrigeration device located outside the battery compartment, and the refrigeration device and the evaporating copper tube are filled with refrigerant, so as to transfer the heat in the coolant to the outside of the battery compartment through the evaporation of the refrigerant in the evaporating copper tube to absorb heat and the liquefaction of the refrigerant in the refrigeration device to release heat;

[0011] In one embodiment, the refrigeration device includes an evaporation copper tube inlet pipe and an evaporation copper tube outlet pipe, one end of the evaporation copper tube inlet pipe and the evaporation copper tube outlet pipe penetrate into the battery compartment and are connected to the evaporation copper tube, and the other end is sequentially connected to a compressor, a condenser, a dryer and an electronic expansion valve;

[0012] Through this implementation, the low-pressure and low-temperature gas evaporated from the evaporating copper tube is converted into high-pressure and high-temperature gas by using a compressor. After passing through the condenser, the high-pressure and high-temperature gaseous refrigerant releases heat and condenses into high-pressure and low-temperature liquid refrigerant. It is dried by the dryer and then passed through the electronic expansion valve to become a low-pressure and low-temperature liquid refrigerant. It evaporates through the evaporating copper tube and absorbs heat, so that the refrigerant circulates in the evaporating copper tube and the refrigeration device to take away the heat in the coolant.

[0013] In one embodiment, the frame includes a plurality of support rods and a plurality of battery trays, wherein the battery trays connect the plurality of support rods together, the plurality of battery trays are evenly spaced in a vertical direction, and each group of battery cells is mounted on one of the battery trays;

[0014] Through this embodiment, the battery tray is used to separate the frame into multiple layers of storage space, so that multiple groups of battery cells in the large-capacity battery pack can be arranged in layers in the vertical direction, and the multiple battery cells in each group of battery cells are placed on the battery tray. That is, the battery tray is set up as a part of the frame and provides support for the large-capacity battery pack.

[0015] In one embodiment, the evaporation copper tube is sequentially coiled along the vertical direction on the support rod and the surface of the battery tray away from the battery cell group;

[0016] Through this embodiment, the frame provided can not only provide support and layering effect for the large-capacity battery pack, but also enable the evaporation copper tube to be coiled on the support rod of the frame and the battery tray, forming a three-dimensional heat dissipation effect for the large-capacity battery pack, thereby improving the temperature uniformity effect of the large-capacity battery pack.

[0017] In one embodiment, the evaporation copper tube includes a first sub-copper tube and a second sub-copper tube, the refrigeration device also includes a condensation branch pipe connected to the dryer and an evaporation branch pipe connected to the compressor, the condensation branch pipe is respectively connected to two evaporation sub-copper tube inlet pipes, the evaporation branch pipe is respectively connected to two evaporation sub-copper tube outlet pipes, the first sub-copper tube and the second sub-copper tube are respectively arranged on the support rods on both sides of the frame, the two evaporation sub-copper tube inlet pipes and the two evaporation sub-copper tube outlet pipes are respectively connected to the first sub-copper tube and the second sub-copper tube, and the two evaporation sub-copper tube inlet pipes are both provided with electronic expansion valves;

[0018] Through this embodiment, two groups of evaporation sub-copper tube inlet pipes and evaporation sub-copper tube outlet pipes are arranged in the refrigeration device, which are respectively connected to the first sub-copper tube and the second sub-copper tube. The first sub-copper tube and the second sub-copper tube are respectively coiled on both sides of the frame, so as to form a three-dimensional heat dissipation effect for the large-capacity battery pack. At the same time, the electronic expansion valve arranged can realize the control of the overheat of the corresponding sub-copper tube branch, so as to improve the temperature uniformity effect of the large-capacity battery pack.

[0019] In one embodiment, a pressure gauge is provided at a portion of the evaporation sub-copper tube outlet located outside the battery compartment, and a first thermometer is provided at a portion of the evaporation sub-copper tube inlet located outside the battery compartment.

[0020] In one embodiment, a second thermometer is further included which is arranged on the frame.

[0021] The present invention also provides a cooling method for a large-capacity battery pack, characterized in that it comprises the following steps:

[0022] Step S1, placing a frame in an immersion liquid cooling device, immersing the frame in cooling liquid, and placing a large-capacity battery pack on the frame;

[0023] Step S2, placing a coiled evaporation copper tube on the frame;

[0024] Step S3, a refrigeration device is arranged outside the immersion liquid cooling device, and the refrigeration device is connected to the evaporating copper tube, so that the refrigerant in the evaporating copper tube circulates in the immersion cold liquid device and the refrigeration device, so that the heat in the coolant is absorbed by the evaporating copper tube and the refrigeration device through the evaporation of the refrigerant and the liquefaction of the refrigerant in the refrigeration device to the outside of the immersion liquid cooling device.

[0025] In one embodiment, it further comprises:

[0026] Step S4, an electronic expansion valve is arranged on the pipeline connecting the refrigeration device and the evaporation copper tube, and the opening of the electronic expansion valve is adjusted according to the temperature of the coolant and the temperature of the inlet and outlet of the refrigeration device.

[0027] In one embodiment, in step S2, a plurality of groups of evaporation sub-copper tubes are respectively arranged along two sides of the frame to fit the frame.

[0028] The beneficial effects of the present invention are:

[0029] It is suitable for refrigeration operations of large-capacity battery packs. It utilizes the phase change of the refrigerant inside the evaporating copper tube and the large specific heat capacity and high heat transfer coefficient of the coolant to quickly remove the heat from the battery cells, improve the heat dissipation efficiency, and ensure the uniform temperature of each battery cell. There is no need to use high-power liquid cooling units or circulating water pumps with high energy consumption, which greatly reduces energy consumption. At the same time, the entire system is relatively simple, saving the company's construction investment cost, and there is no need to design battery packs with IP67 or even higher protection requirements. The design is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0031] Figure 1 A schematic structural diagram of an embodiment of a refrigeration system of the present invention is shown;

[0032] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0033] Reference numerals:

[0034] 1-battery compartment, 2-battery cell, 3-coolant, 4-compressor, 5-condenser, 6-dryer, 7-condensation branch pipe, 8-first electronic expansion valve, 9-second electronic expansion valve, 10-first evaporation sub-copper tube inlet pipe, 11-battery tray, 12-support rod, 14-first evaporation sub-copper tube outlet pipe, 16-second evaporation sub-copper tube inlet pipe, 18-first thermometer, 19-second evaporation sub-copper tube outlet pipe, 20-evaporation branch pipe, 21-pressure gauge, 22-second thermometer, 23-evaporation copper tube. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] The present invention provides a refrigeration system for a large-capacity battery pack, such as Figure 1 As shown, it includes a battery compartment 1 and a coolant 3 filled in the battery compartment 1, a frame immersed in the coolant 3 is installed in the battery compartment 1, and a multi-layer battery cell 2 group is arranged on the frame, and each layer of the battery cell 2 group has a plurality of battery cells 2 directly in contact with the coolant 3;

[0037] The battery compartment 1 is also provided with an evaporation copper tube 23 wound on the frame, and the evaporation copper tube 23 is connected to a refrigeration device located outside the battery compartment 1. The refrigeration device and the evaporation copper tube 23 are filled with refrigerant, so that the heat in the coolant 3 is transferred to the outside of the battery compartment 1 through the refrigerant vaporization heat absorption in the evaporation copper tube 23 and the refrigerant liquefaction heat release in the refrigeration device;

[0038] It should be noted that, since the current battery refrigeration systems have different problems, especially for large-capacity battery packs, it is difficult to reduce the energy consumption and cost of the system while meeting the heat dissipation effect. In this embodiment, while immersing the large-capacity battery pack in the coolant 3, the frame supporting the large-capacity battery pack is used to coil the evaporation copper tube 23 on the frame, and the external refrigeration device is used to work the refrigerant to circulate it in the evaporation copper tube 23, and the heat in the coolant 3 is transferred to the outside of the battery compartment 1 through the refrigerant vaporization heat absorption in the evaporation copper tube 23 and the refrigerant liquefaction heat release in the refrigeration device, that is, the phase change of the refrigerant inside the evaporation copper tube 23 and the large specific heat capacity and high heat transfer coefficient of the coolant 3 are used to quickly take away the heat generated by the battery cell 2, thereby ensuring the heat dissipation effect of the large-capacity battery pack and the temperature uniformity effect of each battery cell 2, and at the same time greatly reducing the required energy consumption, and the whole system has a simple structure and low construction cost, and there is no need to design a battery pack with IP67 or even higher protection requirements, the design is simple and the cost is low, which solves the pain point of enterprises in the heat dissipation problem of large-capacity battery packs during discharge;

[0039] Specifically, the refrigeration device includes an evaporation copper tube 23 inlet pipe and an evaporation copper tube 23 outlet pipe, one end of the evaporation copper tube 23 inlet pipe and the evaporation copper tube 23 outlet pipe penetrate into the battery compartment 1 and are connected to the evaporation copper tube 23, and the other end is sequentially connected to a compressor 4, a condenser 5, a dryer 6 and an electronic expansion valve, that is, the low-pressure and low-temperature gas evaporated from the evaporation copper tube 23 is converted into a high-pressure and high-temperature gas by the compressor 4, and after passing through the condenser 5, the high-pressure and high-temperature gaseous refrigerant releases heat and condenses into a high-pressure and low-temperature liquid refrigerant, and after being dried by the dryer 6, it passes through the electronic expansion valve and becomes a low-pressure and low-temperature liquid refrigerant, so that the refrigerant circulates in the evaporation copper tube 23 and the refrigeration device to take away the heat in the coolant 3;

[0040] Furthermore, the frame includes a plurality of support rods 12 and a plurality of battery trays 11, the battery trays 11 connect the plurality of support rods 12 together, the plurality of battery trays 11 are evenly spaced in the vertical direction, and each group of battery cells 2 is respectively mounted on a battery tray 11, that is, the battery trays 11 are used to separate the frame into multiple layers of storage space, so that the plurality of battery cells 2 in the large-capacity battery pack can be arranged in layers in the vertical direction, and the plurality of battery cells 2 in each group of battery cells 2 are placed on the battery trays 11, that is, the battery trays 11 are arranged as part of the frame, and at the same time provide support for the large-capacity battery pack, and can also provide conditions for the winding of the evaporation copper tube 23;

[0041] In one embodiment, the evaporation copper tube 23 is sequentially coiled on the support rod 12 and the surface of the battery tray 11 away from the battery cell 2 group in the vertical direction, that is, an evaporation copper tube 23 can be arranged so that it is sequentially coiled on the surface of each layer of the battery tray 11 away from the battery cell 2 and the support rod 12 from top to bottom or from bottom to top along the support rod 12 of the frame, forming a three-dimensional heat dissipation structure, that is, the frame is arranged so that the evaporation copper tube 23 can be coiled on the support rod 12 of the frame and the battery tray 11, forming a three-dimensional heat dissipation effect for the large-capacity battery pack, so as to improve the temperature uniformity effect of the large-capacity battery pack;

[0042] In one embodiment, the evaporation copper tube 23 includes a first sub-copper tube and a second sub-copper tube, and the refrigeration device also includes a condensation branch pipe 7 connected to the dryer 6 and an evaporation branch pipe 20 connected to the compressor 4, the condensation branch pipe 7 is respectively connected to two evaporation sub-copper tube inlet pipes, and the evaporation branch pipe 20 is respectively connected to two evaporation sub-copper tube outlet pipes, the first sub-copper tube and the second sub-copper tube are respectively arranged on the support rods 12 on both sides of the frame, the two evaporation sub-copper tube inlet pipes and the two evaporation sub-copper tube outlet pipes are respectively connected to the first sub-copper tube and the second sub-copper tube, the two evaporation sub-copper tube inlet pipes are both provided with electronic expansion valves, the part of the evaporation sub-copper tube outlet pipe located outside the battery compartment 1 is provided with a pressure gauge, the part of the evaporation sub-copper tube inlet pipe located outside the battery compartment 1 is provided with a first thermometer 18, and also includes a second thermometer 22 arranged on the frame;

[0043] It should be noted that if Figure 1 As shown, in this embodiment, a first evaporation sub-copper tube inlet tube 10, a second evaporation sub-copper tube inlet tube 16, a first evaporation sub-copper tube outlet tube 14 and a second evaporation sub-copper tube outlet tube 19 are used. The first evaporation sub-copper tube inlet tube 10 is connected with the first sub-copper tube and the first evaporation sub-copper tube outlet tube 14 in sequence, and the second evaporation sub-copper tube inlet tube 16 is connected with the second sub-copper tube and the second evaporation sub-copper tube outlet tube 19 in sequence, that is, the first sub-copper tube and the second sub-copper tube are respectively coiled on both sides of the frame to take away the heat generated by the battery cell 2, thereby improving the temperature uniformity effect of the large-capacity battery pack. Of course, three or more groups of sub-copper tubes can also be set, and an evaporation sub-copper tube inlet tube and an evaporation sub-copper tube outlet tube can be connected to both ends of each group of sub-copper tubes. Three or more groups of sub-copper tubes can be set on the left and right sides or the front and rear sides of the frame and the bottom surface of the battery tray 11. At the same time, in the case of having multiple groups of sub-copper tubes, such as Figure 1 As shown, the first evaporation sub-copper tube inlet pipe 10 and the second evaporation sub-copper tube inlet pipe 16 are both provided with an electronic expansion valve at the part outside the battery compartment 1, such as Figure 1As shown, the first evaporation sub-copper tube inlet pipe 10 is provided with a first electronic expansion valve 8 at the part outside the battery compartment 1, and the second evaporation sub-copper tube inlet pipe 16 is provided with a second electronic expansion valve 9 at the part outside the battery compartment 1. The temperature in the coolant 3 obtained by the second thermometer 22, the pressure of the refrigerant entering the first evaporation sub-copper tube 10 obtained by the pressure gauge 21, and the temperature of the refrigerant going out of the first evaporation sub-copper tube 14 obtained by the first thermometer 18 are converted into the evaporation temperature according to the pressure value obtained by the pressure gauge 21. The superheat can be obtained by subtracting the evaporation temperature from the temperature obtained by the first thermometer 18. The opening of the first electronic expansion valve 8 is adjusted to control the superheat of the corresponding sub-copper tube, that is, the opening of the electronic expansion valve is adjusted in real time to achieve a rapid temperature control and temperature equalization effect, so as to improve the temperature equalization effect of the large-capacity battery pack. At the same time, corresponding temperature and pressure sensors can be provided on the evaporation sub-copper tube inlet pipe and the evaporation sub-copper tube outlet pipe connected at both ends of each group of sub-copper tubes to adjust the electronic expansion valve in the group of sub-copper tubes to achieve a rapid temperature control and temperature equalization effect.

[0044] Furthermore, in order to more accurately adjust each electronic expansion valve and ensure the heat dissipation effect of the large-capacity battery, the second thermometer 22 in the coolant 3 can be set at the center of the entire large-capacity battery, and installed on the surface of the battery tray 11 away from the battery cell 2;

[0045] The present invention also provides a cooling method for a large-capacity battery pack, comprising the following steps:

[0046] Step S1, placing a frame in an immersion liquid cooling device, immersing the frame in cooling liquid, and placing a large-capacity battery pack on the frame;

[0047] Step S2, placing a coiled evaporation copper tube on the frame;

[0048] Step S3, a refrigeration device is arranged outside the immersion liquid cooling device, and the refrigeration device is connected to the evaporation copper tube, so that the refrigerant in the evaporation copper tube circulates in the immersion liquid cooling device and the refrigeration device, so that the heat in the coolant is absorbed by the evaporation copper tube and the refrigeration device is released to the outside of the immersion liquid cooling device through the evaporation of the refrigerant in the evaporation copper tube and the liquefaction of the refrigerant in the refrigeration device;

[0049] Step S4, installing an electronic expansion valve on the pipeline connecting the refrigeration device and the evaporation copper tube, and adjusting the opening of the electronic expansion valve according to the temperature of the coolant and the temperature of the inlet and outlet of the refrigeration device;

[0050] Wherein, in step S2, a plurality of groups of evaporation sub-copper tubes are respectively arranged along both sides of the frame to fit the frame;

[0051] That is, the refrigeration method provided in this embodiment is suitable for the refrigeration operation of large-capacity battery packs. It uses the phase change of the refrigerant inside the evaporating copper tube and the characteristics of the large specific heat capacity and high heat transfer coefficient of the coolant to quickly take away the heat generated by the battery cell, improve the heat dissipation efficiency, and ensure the uniform temperature effect of each battery cell. There is no need to use a high-power liquid cooling unit, which greatly reduces the loss. The devices designed in this method are relatively simple and common, which can greatly reduce the cost of enterprise construction.

[0052] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0053] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A cooling system for a large-capacity battery pack, characterized in that: It comprises a battery compartment and a coolant filled in the battery compartment, wherein a frame immersed in the coolant is installed in the battery compartment, and a multi-layer battery cell group is arranged on the frame, and each layer of the battery cell group has a plurality of battery cells directly in contact with the coolant; Among them, the battery compartment is also provided with an evaporating copper tube coiled on the frame, and the evaporating copper tube is connected to a refrigeration device located outside the battery compartment. The refrigeration device and the evaporating copper tube are filled with refrigerant to transfer the heat in the coolant to the outside of the battery compartment through the refrigerant vaporizing and absorbing heat in the evaporating copper tube and the refrigerant liquefying and releasing heat in the refrigeration device.

2. A cooling system for a large-capacity battery pack according to claim 1, characterized in that: The refrigeration device includes an evaporation copper tube inlet pipe and an evaporation copper tube outlet pipe, one end of the evaporation copper tube inlet pipe and the evaporation copper tube outlet pipe penetrates into the battery compartment and is connected to the evaporation copper tube, and the other end is sequentially connected to a compressor, a condenser, a dryer and an electronic expansion valve.

3. A cooling system for a large-capacity battery pack according to claim 2, characterized in that: The frame includes a plurality of support rods and a plurality of battery trays. The battery trays connect the plurality of support rods together. The plurality of battery trays are evenly spaced in a vertical direction, and each group of battery cells is mounted on one of the battery trays.

4. A cooling system for a large-capacity battery pack according to claim 3, characterized in that: The evaporation copper tube is coiled in sequence along the vertical direction on the support rod and the surface of the battery tray at a side away from the battery cell group.

5. The cooling system of a large-capacity battery pack according to claim 3, characterized in that: The evaporation copper tube includes a first sub-copper tube and a second sub-copper tube. The refrigeration device also includes a condensation branch pipe connected to the dryer and an evaporation branch pipe connected to the compressor. The condensation branch pipe is respectively connected to two evaporation sub-copper tube inlet pipes, and the evaporation branch pipe is respectively connected to two evaporation sub-copper tube outlet pipes. The first sub-copper tube and the second sub-copper tube are respectively arranged on the support rods on both sides of the frame. The two evaporation sub-copper tube inlet pipes and the two evaporation sub-copper tube outlet pipes are respectively connected to the first sub-copper tube and the second sub-copper tube. The electronic expansion valve is arranged on the two evaporation sub-copper tube inlet pipes.

6. A cooling system for a large-capacity battery pack according to claim 5, characterized in that: A pressure gauge is provided at a portion of the evaporation sub-copper tube outlet located outside the battery compartment, and a first thermometer is provided at a portion of the evaporation sub-copper tube inlet located outside the battery compartment.

7. A cooling system for a large-capacity battery pack according to claim 3, characterized in that: Also included is a second thermometer disposed on the frame.

8. A cooling method for a large-capacity battery pack, characterized in that: The steps include: Step S1, placing a frame in an immersion liquid cooling device, immersing the frame in cooling liquid, and placing a large-capacity battery pack on the frame; Step S2, placing a coiled evaporation copper tube on the frame; Step S3, a refrigeration device is arranged outside the immersion liquid cooling device, and the refrigeration device is connected to the evaporating copper tube, so that the refrigerant in the evaporating copper tube circulates in the immersion cold liquid device and the refrigeration device, so that the heat in the coolant is absorbed by the evaporating copper tube and the refrigeration device through the evaporation of the refrigerant and the liquefaction of the refrigerant in the refrigeration device to the outside of the immersion liquid cooling device.

9. A cooling method for a large-capacity battery pack according to claim 8, characterized in that: Also includes: Step S4, an electronic expansion valve is arranged on the pipeline connecting the refrigeration device and the evaporation copper tube, and the opening of the electronic expansion valve is adjusted according to the temperature of the coolant and the temperature of the inlet and outlet of the refrigeration device.

10. The cooling method of a large-capacity battery pack according to claim 8, characterized in that: In step S2, a plurality of groups of evaporation sub-copper tubes are respectively arranged along two sides of the frame to fit the frame.

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