Liquid cooling system and battery pack

Abstract

The utility model provides a liquid cooling system and a battery pack. The liquid cooling system comprises a liquid cooling plate, the liquid cooling plate comprises two plate bodies which are vertically arranged at an interval and a partition plate arranged between the two plate bodies, flow channel cavities are defined by the two sides of the partition plate and the plate bodies on the same side, each plate body is provided with a liquid inlet and a liquid outlet which are communicated with the flow channel cavities on the same side, one flow channel cavity is used for circulation of refrigerants, and the other flow channel cavity is used for circulation of the refrigerants. And the other runner cavity is used for circulating heat conduction liquid. According to the liquid cooling system provided by the utility model, the partition plate is arranged between the two plate bodies, the two sides of the partition plate and the plate bodies on the same side are respectively enclosed to form the flow channel cavities, one flow channel cavity is used for circulating the refrigerant, and the other flow channel cavity is used for circulating the heat conduction liquid, so that the refrigerant and the heat conduction liquid can be used independently or cooperatively; therefore, the cooling effect and the temperature uniformity of the battery pack are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and in particular to a liquid cooling system. Meanwhile, the utility model also relates to a battery pack provided with the liquid cooling system. Background Art

[0002] With the promotion and application of power batteries, people's requirements for battery safety are getting higher and higher. Liquid cooling plates, as an important component of battery packs, are mainly used for cooling battery packs. However, traditional liquid cooling plates usually have channels inside for coolant to flow through. The coolant takes away the heat of the battery cells, which helps the battery cells in the battery pack to cool to a suitable temperature range, thereby ensuring the safety of the battery pack.

[0003] Although some liquid cooling plates use refrigerant instead of coolant to cool the battery pack, the outlet of the refrigerant solution requires a certain degree of superheat to prevent compressor liquid hammer, which results in a large temperature difference in the battery pack and is not conducive to the uniformity of the battery pack temperature. Utility Model Content

[0004] In view of this, the utility model aims to provide a liquid cooling system to improve the cooling effect of the battery cell and the temperature uniformity of the battery pack.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A liquid cooling system includes a liquid cooling plate; the liquid cooling plate includes two plate bodies spaced apart from each other in an upper and lower manner, and a partition plate arranged between the two plate bodies, flow channel cavities are respectively formed between the two sides of the partition plate and the plate bodies on the same side, each of the plate bodies is provided with a liquid inlet and a liquid outlet respectively connected to the flow channel cavity on the same side, and one of the flow channel cavities is used for circulating refrigerant, and the other flow channel cavity is used for circulating heat transfer liquid.

[0007] Furthermore, each of the flow channel cavities is provided with a plurality of flow channels extending along the first direction of the plate body, the plurality of flow channels are arranged at intervals in the second direction of the plate body, and the plurality of flow channels on both sides are arranged alternately in the second direction of the plate body; the first direction and the second direction are arranged orthogonally.

[0008] Furthermore, each of the plate bodies is provided with two communicating cavities arranged opposite to each other, the communicating cavities are respectively communicated with each of the flow channels on the same side, the liquid inlet is communicated with one of the communicating cavities, and the liquid outlet is communicated with the other communicating cavity.

[0009] Furthermore, a plurality of flow channel grooves alternately arranged along the second direction are respectively provided on both sides of the partition, and each of the flow channel grooves and the plate body on the same side respectively form the flow channel.

[0010] Furthermore, the partition is provided with a plurality of protrusions arched out to one side and extending along the first direction, and the plurality of protrusions are arranged at intervals along the second direction;

[0011] The plurality of flow channel grooves located on one side of the partition are formed between two adjacent protrusions, and the plurality of flow channel grooves located on the other side of the partition are formed in each protrusion.

[0012] Furthermore, the partition includes a body having a plurality of protrusions and two blocking plates;

[0013] Each of the protrusions is arranged through the two ends of the body, and the two blocking plates are arranged at the two ends of the body to form the end of each of the flow channel grooves.

[0014] Furthermore, the cross section of the protrusion is trapezoidal; and / or,

[0015] The top and the bottom of the protrusion are respectively connected to the corresponding plate body by welding.

[0016] Furthermore, it also includes a refrigeration circuit through which the refrigerant flows, and a heating circuit through which the heat transfer fluid flows, and the refrigeration circuit is connected to one of the flow channel cavities, and the heating circuit is connected to the other of the flow channel cavities;

[0017] The refrigeration circuit is provided with a compressor, a condenser and an electronic expansion valve in sequence;

[0018] The heating circuit is provided with a heating part for heating the thermal fluid and a water pump for driving the thermal fluid to flow.

[0019] Furthermore, the heating circuit is provided with a branch pipeline arranged in parallel with the heating part;

[0020] A three-way valve is connected between the branch pipeline, the heating part and the heating circuit, and the three-way valve constitutes conduction or disconnection between the heating part or the branch pipeline and the flow channel cavity.

[0021] Compared with the prior art, the utility model has the following advantages:

[0022] The liquid cooling system described in the utility model is provided with a partition between two plate bodies, and flow channel cavities are respectively formed between the two sides of the partition and the plate bodies on the same side, and one flow channel cavity is used for circulating refrigerant, and the other flow channel cavity is used for circulating heat transfer liquid, so that the refrigerant and the heat transfer liquid can be used separately or in combination, thereby helping to improve the cooling effect and temperature uniformity of the battery pack.

[0023] In addition, by providing multiple flow channels in each flow channel cavity, the cooling efficiency of the battery pack can be further improved. The provision of the connecting cavity on the plate body facilitates the inflow or outflow of the refrigerant or heat transfer fluid in each flow channel, and is easy to arrange and implement. The flow channel groove on the partition is conducive to the formation of the flow channel and to ensuring the plane integrity of the plate body, thereby facilitating the improvement of the cooling effect on the battery pack. By providing a protrusion on the partition, it is not only conducive to the formation of the flow channel groove, but also conducive to improving the structural strength of the partition. The provision of the main body and the blocking plate in the partition is conducive to the processing and forming of the flow channel groove and the use effect.

[0024] In addition, the cross-section of the protrusion is trapezoidal, which is not only conducive to processing and forming, but also conducive to improving the structural strength of the partition; the top of the protrusion is welded to the plate body, which is conducive to improving the structural strength and reliability of the liquid cooling plate, and is also conducive to improving the heat exchange effect of the refrigerant and the thermal fluid. The setting of the refrigeration circuit and the heating circuit is conducive to the circulation of the refrigerant and the thermal fluid, thereby ensuring the cooling effect and cooling efficiency. By setting up branch pipes and three-way valves, it is convenient to adjust the temperature of the thermal fluid, so as to meet the use requirements under different conditions. The flow channel cavity through which the refrigerant flows is set toward the battery module, which is conducive to the refrigerant cooling the battery module, and has better cooling efficiency.

[0025] In addition, another object of the present invention is to provide a battery pack, comprising a lower housing having a mounting cavity, a battery module, and the liquid cooling system as described above;

[0026] The liquid cooling plate is arranged at the bottom of the installation cavity, and the battery module is arranged on the liquid cooling plate.

[0027] The battery pack described in the present invention is beneficial to the cooling effect and uniformity of the battery pack by providing the above liquid cooling system, thereby improving the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the structure of the liquid cooling plate according to an embodiment of the utility model;

[0030] Figure 2 This is a disassembly diagram of the liquid cooling plate described in the embodiment of the utility model;

[0031] Figure 3 This is a schematic diagram of the structure of the partition described in the embodiment of the utility model;

[0032] Figure 4 for Figure 3 A magnified view of part A in FIG.

[0033] Figure 5 A top view of the liquid cooling plate according to an embodiment of the utility model;

[0034] Figure 6 for Figure 5 BB direction cross-sectional view;

[0035] Figure 7 for Figure 5 The CC direction cross-sectional view;

[0036] Figure 8 This is a disassembly diagram of the battery pack described in the embodiment of the utility model;

[0037] Fig. 9 This is a disassembly diagram of the liquid cooling system according to an embodiment of the utility model;

[0038] Fig.10 This is a schematic diagram of the connection between the refrigeration circuit and the heating circuit described in an embodiment of the utility model.

[0039] Description of reference numerals:

[0040] 1. Upper cover; 2. Battery module; 3. Thermal conductive adhesive; 4. Frame; 401. Bottom guard plate; 5. Liquid cooling plate; 6. Battery cell; 7. Electronic expansion valve; 8. Condenser; 9. Compressor; 10. Gas-liquid separator; 11. Water pump; 12. Heating unit; 13. Three-way valve;

[0041] 100, flow channel; 200, refrigeration circuit; 300, branch pipeline; 400, heating circuit; 500, flow channel cavity;

[0042] 501, plate body; 5011, connecting box; 5012, liquid inlet; 5013, liquid outlet; 5014, connecting port; 502, partition; 5021, main body; 5022, blocking plate; 5023, protrusion. DETAILED DESCRIPTION

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0044] In the description of the present invention, it should be noted that if there are terms indicating orientation or positional relationship such as "upper", "lower", "inner", "back", etc., they are based on the orientation or positional relationship shown in the 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 limiting the present invention. In addition, if there are terms such as "first", "second", etc., they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0046] The present embodiment relates to a liquid cooling system to improve the cooling effect and temperature uniformity of a battery pack.

[0047] In terms of overall structure, the liquid cooling system includes a liquid cooling plate 5. The liquid cooling plate 5 includes two plate bodies 501 arranged at an interval from top to bottom, and a partition 502 disposed between the two plate bodies 501, and flow channel cavities 500 are respectively formed between the two sides of the partition 502 and the plate body 501 on the same side. Each plate body 501 is provided with a liquid inlet 5012 and a liquid outlet 5013 respectively connected to the flow channel cavity 500 on the same side, and one flow channel cavity 500 is used to circulate the refrigerant, and the other flow channel cavity 500 is used to circulate the heat transfer liquid.

[0048] The liquid cooling system of this embodiment is provided with a partition 502 between two plate bodies 501, and flow channel cavities 500 are respectively formed between the two sides of the partition 502 and the plate body 501 on the same side, and one flow channel cavity 500 is used for circulating refrigerant, and the other flow channel cavity 500 is used for circulating heat transfer liquid, so that the refrigerant and the heat transfer liquid can be used separately or in combination, thereby helping to improve the cooling effect and temperature uniformity of the battery pack.

[0049] Based on the above overall introduction, an exemplary structure of the liquid cooling system in this embodiment is as follows: Figure 1 and Figure 2 The structure of the liquid cooling plate 5 is shown in Figure 3 and Figure 4 As shown in the figure, the structure of the liquid cooling plate 5 is described below. Two plates 501 are arranged in parallel and spaced apart, and a partition 502 is provided between the two plates 501 to form a connection between the two plates 501. The shape of the plate 501 here can be a rectangle as shown in the figure, or a square or other geometric shape, as long as it meets the use requirements.

[0050] The refrigerant in this embodiment can be a refrigerant in the prior art, such as R134a, etc. The thermal conductive liquid can be a thermal conductive liquid in the prior art, such as a 50% ethylene glycol aqueous solution, etc. In this embodiment, the battery module 2 can be heated by heating the thermal conductive liquid.

[0051] As a preferred embodiment, Figures 5 to 7 As shown in , each flow channel cavity 500 is provided with a plurality of flow channels 100 extending along the first direction of the plate body 501, the plurality of flow channels 100 are arranged at intervals in the second direction of the plate body 501, and the plurality of flow channels 100 on both sides are arranged alternately in the second direction of the plate body 501; the first direction and the second direction are arranged orthogonally. Here, by providing a plurality of flow channels 100 in each flow channel cavity 500, the cooling efficiency of the battery pack is further improved.

[0052] Specifically, in this embodiment, one of the first direction and the second direction may be the length direction of the plate 501, and the other may be the width direction of the plate 501. Figure 4 As shown in , the first direction is the length direction of the plate 501, and the second direction is the width direction of the plate 501. At this time, the refrigerant or the heat transfer liquid can flow from one end of the partition 502 to the other end through each flow channel 100, and take away the heat of the battery cell 6 connected to the liquid cooling plate 5, thereby achieving the effect of cooling the battery pack.

[0053] To facilitate the inflow and outflow of refrigerant and heat transfer liquid, two relatively arranged connecting cavities are provided on each plate body 501, and the connecting cavities are respectively connected to each flow channel 100 on the same side, the liquid inlet 5012 is connected to one connecting cavity, and the liquid outlet 5013 is connected to the other connecting cavity.

[0054] In terms of specific structure, Figure 2 As shown in , a communication port 5014 extending along the second direction is respectively provided at both ends of each plate body 501, a communication box 5011 having a communication cavity is buckled on the plate body 501, and the communication box 5011 is buckled at both ends of the plate body 501, and is connected to the corresponding communication port 5014, and is connected to the flow channel cavity 500 through the communication port 5014. The liquid inlet 5012 and the liquid outlet 5013 are respectively provided on the corresponding communication box 5011.

[0055] Preferably, the liquid inlet 5012 and the liquid outlet 5013 are arranged in the middle of the connecting box 5011, which helps the refrigerant or thermal liquid to flow into each flow channel 100 more evenly through the liquid inlet 5012 and flow out through the liquid outlet 5013, thereby helping to improve the uniformity of the refrigerant and thermal liquid in the flow channel 100.

[0056] As a preferred embodiment, Figure 4 As shown in , a plurality of flow channel grooves alternately arranged along the second direction are respectively provided on both sides of the partition 502, and each flow channel groove is respectively formed with the plate body 501 on the same side to form a flow channel 100. Here, the flow channel grooves on the partition 502 are conducive to forming the flow channel 100 and ensuring the plane integrity of the plate body 501, thereby facilitating the improvement of the cooling effect on the battery pack.

[0057] In terms of detailed structure, Figure 4 As shown in FIG, a plurality of protrusions 5023 are provided on the partition plate 502, which are arched toward one side and extend along the first direction, and the plurality of protrusions 5023 are arranged at intervals along the second direction. A plurality of flow channel grooves located on one side of the partition plate 502 are formed between two adjacent protrusions 5023, and a plurality of flow channel grooves located on the other side of the partition plate 502 are formed in each protrusion 5023. By providing the protrusions 5023 on the partition plate 502, it is not only beneficial to form the flow channel grooves, but also beneficial to improve the structural strength of the partition plate 502.

[0058] In this embodiment, relative to the protruding direction of the protrusion 5023, the two sides of the partition 502 in the width direction are respectively connected to the plate body 501 on the other side, which is conducive to improving the sealing of the flow channel cavity 500 in the width direction. Figure 2 and Figure 6 As shown in , the partition 502 includes a body 5021 having a plurality of protrusions 5023 and two blocking plates 5022. Each protrusion 5023 is arranged through both ends of the body 5021. The two blocking plates 5022 are arranged at both ends of the body 5021 to form the ends of each flow channel groove. The two ends of two adjacent protrusions 5023 and the two ends inside the protrusions 5023 are open. Each blocking plate 5022 is connected to the two ends of the partition 502 and blocks the openings at the same end, thereby facilitating the separation of each flow channel 100.

[0059] In a specific implementation, each protrusion 5023 on the partition 502 can be formed by stamping. The cross section of the protrusion 5023 is trapezoidal, which is not only conducive to processing and forming, but also conducive to improving the structural strength of the partition 502. Figure 7 As shown in , the top and bottom of the protrusion 5023 are respectively welded to the corresponding plate body 501. In specific implementation, the top and bottom of the protrusion 5023 are welded to the corresponding plate body 501 by brazing or laser welding, which is beneficial to improve the structural strength and reliability of the liquid cooling plate 5.

[0060] In this embodiment, by providing a plurality of protrusions 5023 on the partition 502, it is not only conducive to the forming and separation of the two flow channel cavities 500, so that the media in the two flow channel cavities 500 can flow independently of each other, but also can guide the refrigerant or heat transfer liquid to flow from one end of the plate body 501 to the other end, thereby improving the cooling effect on the battery pack.

[0061] It should be noted that in this embodiment, a protrusion 5023 structure can also be set on the plate body 501. In this case, there is no need to set the protrusion 5023 structure on the upper side of the plate body 501 on the same side. It is only necessary to ensure that a flow channel 100 is formed between the plate body 501 on one side of the partition 502 and the partition 502.

[0062] As a preferred embodiment, Fig.10As shown in , the liquid cooling system in this embodiment also includes a refrigeration circuit 200 through which a refrigerant flows, and a heating circuit 400 through which a thermal liquid flows, and the refrigeration circuit 200 is connected to one of the flow channel cavities 500, and the heating circuit 400 is connected to the other flow channel cavity 500. Among them, the refrigeration circuit 200 is provided with a compressor 9, a condenser 8, and an electronic expansion valve 79 in sequence. The heating circuit 400 is provided with a heating part 12 for heating the thermal liquid, and a water pump 11 for driving the thermal liquid to flow. Here, the setting of the refrigeration circuit 200 and the heating circuit 400 is conducive to the circulation of the refrigerant and the thermal liquid, thereby ensuring the cooling effect and cooling efficiency.

[0063] Specifically, the compressor 9, the condenser 8 and the electronic expansion valve 7 are sequentially arranged upstream of the flow channel cavity 500 through which the refrigerant flows. In addition, a gas-liquid separator 10 is also arranged downstream of the flow channel cavity 500 through which the refrigerant flows and between the compressor 9. The arrangement of the refrigeration circuit 200 here is conducive to the circulation flow channel 100 of the refrigerant, and is conducive to ensuring the state of the refrigerant flowing into the flow channel cavity 500, thereby helping to improve the refrigerant's absorption effect on the heat of the battery pack.

[0064] Furthermore, in this embodiment, the heating circuit 400 is provided with a branch pipeline 300 arranged in parallel with the heating part 12, and a three-way valve 13 is connected between the branch pipeline 300, the heating part 12 and the heating circuit 400, and the three-way valve 13 constitutes the conduction or disconnection between the heating part 12 or the branch pipeline 300 and the flow channel cavity 500. By providing the branch pipeline 300 and the three-way valve 13, it is convenient to adjust the problem of the heat transfer fluid, thereby meeting the use requirements under different states. In specific implementation, the heating part 12 can adopt a PTC water heater or the like.

[0065] In this embodiment, the flow channel cavity 500 through which the refrigerant flows is arranged toward the battery module 2, which is conducive to the refrigerant cooling the battery module 2 and has a good cooling efficiency. The liquid cooling system in this embodiment can not only be used for cooling the bottom of the battery cell 6, but also for cooling the large surface of the battery cell 6, so that the cooling efficiency of the battery cell 6 is higher and it can be used for high-rate fast charging.

[0066] When the liquid cooling system is used in low temperature heating and fast charging state, such as Fig.10 As shown in the figure, the refrigerant in the refrigeration circuit 200 does not flow (does not work), the heat transfer fluid in the heating circuit 400 flows (works), and the heat transfer fluid passes through the flow channel cavity 500, the three-way valve 13, the PTC water heater and the water pump 11 to form a loop, and the heat transfer fluid is heated by the PTC water heater, and then the battery cell 6 is heated.

[0067] When the liquid cooling system is used in the normal temperature fast charging and high temperature fast charging states of the battery pack, if the temperature difference of the battery cell 6 is not large, the refrigerant flows (works) and the thermal liquid does not flow (does not work). The refrigerant passes through the compressor 9, the condenser 8, the electronic expansion valve 7, the flow channel cavity 500 and the gas-liquid separator 10 to form a refrigeration circuit 200 to cool the battery cell 6.

[0068] When the liquid cooling system is used in the battery pack normal temperature fast charging and high temperature fast charging states, if the temperature difference of the battery cell 6 is large, the refrigerant flows (works) and the thermal conductive liquid flows (works). The refrigerant flows in the same way as above, and the thermal conductive liquid part works as follows: the thermal conductive liquid passes through the flow channel cavity 500, and the three-way valve 13 and the water pump 11 form a loop. At this time, the heating part 12 does not work. The battery pack is directly cooled by the refrigerant, and the temperature of the battery cell 6 is adjusted by the self-circulation of the thermal conductive liquid, thereby reducing the temperature difference of the battery cell 6.

[0069] In addition, the present embodiment also relates to a battery pack, including a lower shell having an installation cavity, a battery module 2, and the liquid cooling system as described above. The liquid cooling plate 5 is arranged at the bottom of the installation cavity, and the battery module 2 is arranged on the liquid cooling plate 5. The flow channel cavity 500 through which the refrigerant flows is arranged at the top, and the flow channel cavity 500 through which the heat transfer liquid flows is arranged at the bottom.

[0070] Specifically, if Figure 8 As shown in the figure, the lower shell in this embodiment includes a hollow frame 4, a bottom guard plate 401 blocking the bottom of the frame 4, and a liquid cooling plate 5 is arranged on the frame 4 and above the bottom guard plate 401. The battery module 2 is connected to the liquid cooling plate 5 through a thermal conductive adhesive 3. The battery pack in this embodiment also includes an upper cover 1 buckled on the lower shell.

[0071] The battery pack in this embodiment is provided with the above-mentioned liquid cooling system, which is beneficial for the refrigerant to cool the battery module 2 alone, the thermal liquid to heat the battery module 2 alone, and the refrigerant to adjust the temperature difference of the battery pack by self-circulation of the thermal liquid while cooling the battery module 2, which is beneficial to improve the cooling uniformity of the liquid cooling system on the battery module 2, thereby helping to improve the safety of the battery pack.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquid cooling system, characterized in that: Includes liquid cooling plate; The liquid cooling plate includes two plate bodies spaced apart from each other in an upper and lower manner, and a partition plate arranged between the two plate bodies. A flow channel cavity is respectively formed between the two sides of the partition plate and the plate body on the same side. Each of the plate bodies is provided with a liquid inlet and a liquid outlet respectively connected to the flow channel cavity on the same side, and one of the flow channel cavities is used for circulating refrigerant, and the other flow channel cavity is used for circulating heat transfer liquid.

2. The liquid cooling system according to claim 1, characterized in that: Each of the flow channel cavities is provided with a plurality of flow channels extending along the first direction of the plate body, the plurality of flow channels are arranged at intervals in the second direction of the plate body, and the plurality of flow channels on both sides are arranged alternately in the second direction of the plate body; The first direction and the second direction are arranged orthogonally.

3. The liquid cooling system according to claim 2, characterized in that: Two communicating cavities are arranged opposite to each other on each of the plate bodies. The communicating cavities are respectively communicated with the flow channels on the same side. The liquid inlet is communicated with one of the communicating cavities, and the liquid outlet is communicated with the other communicating cavity.

4. The liquid cooling system according to claim 2, characterized in that: A plurality of flow channel grooves alternately arranged along the second direction are respectively provided on both sides of the partition plate, and each of the flow channel grooves and the plate body on the same side respectively form the flow channel.

5. The liquid cooling system according to claim 4, characterized in that: The partition plate is provided with a plurality of protrusions arched toward one side and extending along the first direction, and the plurality of protrusions are arranged at intervals along the second direction; The plurality of flow channel grooves located on one side of the partition are formed between two adjacent protrusions, and the plurality of flow channel grooves located on the other side of the partition are formed in each protrusion.

6. The liquid cooling system according to claim 5, characterized in that: The partition includes a body having a plurality of protrusions and two blocking plates; Each of the protrusions is arranged through the two ends of the body, and the two blocking plates are arranged at the two ends of the body to form the end of each of the flow channel grooves.

7. The liquid cooling system according to claim 5, characterized in that: The cross section of the protrusion is trapezoidal; and / or, The top and the bottom of the protrusion are respectively connected to the corresponding plate body by welding.

8. The liquid cooling system according to any one of claims 1 to 7, characterized in that: It also includes a refrigeration circuit through which the refrigerant flows, and a heating circuit through which the heat transfer fluid flows, wherein the refrigeration circuit is in communication with one of the flow channel cavities, and the heating circuit is in communication with the other of the flow channel cavities; The refrigeration circuit is provided with a compressor, a condenser and an electronic expansion valve in sequence; The heating circuit is provided with a heating part for heating the thermal fluid and a water pump for driving the thermal fluid to flow.

9. The liquid cooling system according to claim 8, characterized in that: The heating circuit is provided with a branch pipeline arranged in parallel with the heating part; A three-way valve is connected between the branch pipeline, the heating part and the heating circuit, and the three-way valve constitutes conduction or disconnection between the heating part or the branch pipeline and the flow channel cavity.

10. A battery pack, characterized in that: It comprises a lower housing having a mounting cavity, a battery module and a liquid cooling system as claimed in any one of claims 1 to 9; The liquid cooling plate is arranged at the bottom of the installation cavity, and the battery module is arranged on the liquid cooling plate.

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