Liquid cooling system, battery pack and electric device

Abstract

Provided in the present application are a liquid cooling system and a battery pack. The liquid cooling system is used in the battery pack, and the battery pack comprises at least one battery cell group. The liquid cooling system comprises at least one supporting liquid cooling plate and a top liquid cooling plate. Each supporting liquid cooling plate is used for supporting the bottom of a corresponding battery cell group and cooling said battery cell group. The top liquid cooling plate is located above the at least one supporting liquid cooling plate, and is arranged on the top of a corresponding battery cell group and used for cooling said battery cell group. The thickness of the supporting liquid cooling plate is greater than that of the top liquid cooling plate.

Description

Liquid cooling system, battery pack and electric device

[0001] The present application claims priority to the Chinese patent application No. 202421800008.1 filed on July 26, 2024 with the China Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of batteries, in particular to a liquid cooling system and a battery pack. BACKGROUND

[0003] At present, the application of electric household vehicles is relatively common. With the development of the electric vehicle industry and in order to meet future commercial needs, electric commercial vehicles such as electric trucks may appear in the future, and the power required to run electric commercial vehicles is greater than the power required to run current electric household vehicles. SUMMARY

[0004] The power required by the electric commercial vehicles that will appear in the future is greater than the power required to run current electric household vehicles, so the number of battery packs included in the electric commercial vehicles is greater, and the cooling system in the related art is not suitable for the scenario where the number of battery packs is greater.

[0005] To this end, the present application adopts the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a liquid cooling system for a battery pack, the battery pack including at least one cell group, the liquid cooling system including: at least one support liquid cooling plate, each support liquid cooling plate being used to support the bottom of a corresponding cell group and cool the cell group; and a top liquid cooling plate located above the at least one support liquid cooling plate and used to abut the top of the corresponding cell group and cool the cell group; wherein the thickness of the support liquid cooling plate is greater than the thickness of the top liquid cooling plate.

[0007] In a second aspect, an embodiment of the present application provides a battery pack including the liquid cooling system of the first aspect.

[0008] In a third aspect, an embodiment of the present application provides an electric device including the battery pack of the second aspect. ADVANTAGEOUS EFFECTS

[0009] The liquid cooling system provided in the application is used for a battery pack, and the battery pack comprises at least one cell group, and the liquid cooling system comprises at least one supporting liquid cooling plate and a top liquid cooling plate, wherein each supporting liquid cooling plate is used for supporting the bottom of the corresponding cell group and cooling the cell group. The top liquid cooling plate is located above the at least one supporting liquid cooling plate, is used for abutting against the top of the corresponding connecting plate cell group and cooling the connecting plate cell group, and the thickness of the supporting liquid cooling plate is greater than the thickness of the top liquid cooling plate. The liquid cooling system can reduce the space occupancy of the liquid cooling plate and the cell group through the laminated design, and on this basis, the thickness of the supporting liquid cooling plate is set to be greater than the thickness of the top liquid cooling plate, so that the supporting liquid cooling plate not only provides the cooling effect for the cell group, but also guarantees that the supporting liquid cooling plate has sufficient structural strength to provide the supporting effect for the cell group to guarantee the stability of the overall structure. Compared with the single-side cooling of the cell group in the related art, the cooling system has higher heat dissipation efficiency, and the heat distribution of each cell group is more uniform, that is, the temperature difference between the top and the bottom of the cell group is smaller, and the safety of the cell group can be well guaranteed.

[0010] The battery pack provided in the application has all the advantages of the liquid cooling system.

[0011] The power consumption equipment provided in the application has all the advantages of the battery pack. BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a structural schematic diagram of a liquid cooling system provided in an embodiment of the application;

[0013] FIG. 2 is a structural schematic diagram of the liquid cooling system in FIG. 1 with a hidden side plate;

[0014] FIG. 3 is a structural schematic diagram of a pipeline structure in FIG. 2;

[0015] FIG. 4 is a top view of FIG. 1;

[0016] FIG. 5 is a sectional view of FIG. 4;

[0017] FIG. 6 is a structural schematic diagram of a supporting liquid cooling plate in FIG. 2;

[0018] FIG. 7 is a top view of FIG. 6;

[0019] FIG. 8 is a sectional view of FIG. 7;

[0020] FIG. 9 is an enlarged view of part D in FIG. 8;

[0021] FIG. 10 is a structural schematic diagram of a top liquid cooling plate in FIG. 2;

[0022] FIG. 11 is a top view of FIG. 10;

[0023] FIG. 12 is a sectional view of FIG. 11;

[0024] FIG. 13 is an enlarged view of part B in FIG. 12;

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] 100, liquid cooling system; 110, support liquid cooling plate; 111, first flow channel; 120, top liquid cooling plate; 121, second flow channel; 122, base plate; 123, connecting plate; 130, pipeline structure; 131, main pipeline assembly; 132, water nozzle; 133, wall penetration joint; 200, battery cell group; 300, side plate. Embodiments of the application

[0027] In order to solve the problem of insufficient cooling capacity of the cooling system when the battery pack is more, the embodiment of the application provides a liquid cooling system 100 for a battery pack, which can be referred to as FIG. 1 and FIG. 2. FIG. 1 is a structural schematic diagram of the liquid cooling system 100 provided by the embodiment of the application, and FIG. 2 is a structural schematic diagram of the liquid cooling system 100 in FIG. 1 hidden side plate 300. The battery pack includes at least one battery cell group 200, and each battery cell group 200 includes a plurality of battery cells. The liquid cooling system 100 includes at least one support liquid cooling plate 110 and a top liquid cooling plate 120. Each support liquid cooling plate 110 is used to support the bottom of the corresponding battery cell group 200 and cool the battery cell group 200. The top liquid cooling plate 120 is located above the at least one support liquid cooling plate 110. One battery cell group 200 is supported on the support liquid cooling plate 110 close to the top liquid cooling plate 120. The top liquid cooling plate 120 is used to abut the top of the battery cell group 200 and provide cooling function for it. At the same time, the thickness of the support liquid cooling plate 110 is greater than the thickness of the top liquid cooling plate 120.

[0028] Specifically, refer to FIG. 2. In the liquid cooling system 100, a plurality of support liquid cooling plates 110 and a top liquid cooling plate 120 are stacked. The top liquid cooling plate 120 is located on one side of the plurality of support liquid cooling plates 110. An electric cell group 200 is arranged between every two adjacent support liquid cooling plates 110. The two adjacent support liquid cooling plates 110 simultaneously cool the top and bottom of the corresponding battery cell group 200 to enhance the cooling effect of the cooling system. The support liquid cooling plate 110 with a relatively large thickness not only provides cooling effect for the bottom of the corresponding battery cell group 200, but also provides support for the corresponding battery cell group 200. The top liquid cooling plate 120 with a relatively small thickness abuts the top of the uppermost battery cell group 200 and provides cooling effect for the top of the uppermost battery cell group 200.

[0029] In this embodiment, through the laminated design between the liquid cooling plate and the battery cell group 200, the space occupation of the two can be reduced. On this basis, the thickness of the support liquid cooling plate 110 is set to be greater than the thickness of the top liquid cooling plate 120, so that the support liquid cooling plate 110 can not only provide cooling effect for the corresponding battery cell group 200, but also ensure that the support liquid cooling plate 110 has sufficient structural strength to provide support for the corresponding battery cell group 200, so as to ensure the stability of the overall structure. By arranging the corresponding battery cell group 200 between the two adjacent liquid cooling plates, the top and bottom of the battery cell group 200 can be cooled at the same time. Compared with the related art in which the battery cell group 200 is cooled on one side, the cooling system provided in this embodiment has higher heat dissipation efficiency, and the heat distribution of each battery cell group 200 is more uniform, the temperature difference between the top and bottom of the battery cell group 200 is smaller, and the safety of the battery cell group 200 can be well ensured.

[0030] In some embodiments, reference can be made to FIG. 2 and FIG. 3, which is a structural schematic diagram of the pipeline structure 130 in FIG. 2. The liquid cooling system 100 further comprises a pipeline structure 130. The support liquid cooling plate 110 is provided with a first flow channel 111 for flowing cooling medium, and the top liquid cooling plate 120 is provided with a second flow channel 121 for flowing cooling medium. The first flow channel 111 is connected to the second flow channel 121 through the pipeline structure 130. The pipeline structure 130 comprises at least one main pipeline assembly 131 and at least one water nozzle 132. One end of each water nozzle 132 is connected to the second flow channel 121 of the top liquid cooling plate 120 through the corresponding main pipeline assembly 131 (see FIG. 13), and the other end of each water nozzle 132 is connected to the first flow channel 111 of the corresponding support liquid cooling plate 110 (see FIG. 9).

[0031] Specifically, the water nozzle 132 in this embodiment is an integrally formed structure, one end of which is connected to the corresponding main pipeline assembly 131, and the other end of which is connected to the corresponding support liquid cooling plate 110. In the related art, a male connector is provided on the liquid cooling plate, one end of a female connector is connected to the male connector, and the other end of the female connector is connected to one end of a pipeline, and the other end of the pipeline is connected to the main pipeline assembly 131. Therefore, compared with the pipeline structure in the related art, the pipeline structure 130 in this embodiment has a simpler structure and occupies less space.

[0032] In some embodiments, reference can be made to FIG. 4 and FIG. 5, which is a top view of FIG. 1 and a sectional view of FIG. 4. The pipeline structure 130 comprises at least one wall penetrating connector 133, one end of each wall penetrating connector 133 is connected to the corresponding main pipeline assembly 131, and the other end of the wall penetrating connector 133 is used to penetrate the side plate 300 of the battery pack box to connect to an external cooling medium source. The wall penetrating connector 133 comprises two abutting portions located on both sides of the side plate 300, which abut against both sides of the side plate 300, respectively.

[0033] In the embodiment, the two abutting parts of the wall-through connector 133 abut against the side plates 300 of the battery pack, and one end of the wall-through connector 133 communicates with the corresponding main pipe assembly 131, and the other end of the wall-through connector 133 communicates with the external cooling medium source, so that the structural position between the wall-through connector 133, the pipe structure 130 and the battery pack can be kept stable when the cooling system transmits the cooling medium.

[0034] In some embodiments, reference can be made to FIG. 3 and FIG. 5. One end of the top liquid cooling plate 120 exceeds one end of at least one supporting liquid cooling plate 110 in the length direction of the top liquid cooling plate 120, and each main pipe assembly 131 is connected to the bottom surface of one end of the top liquid cooling plate 120 and is also connected to the top surface of one end of the corresponding supporting liquid cooling plate 110 through the corresponding water nozzle 132.

[0035] In the embodiment, by designing one end of the top liquid cooling plate 120 to exceed one end of at least one supporting liquid cooling plate 110 in the length direction of the top liquid cooling plate 120, the main pipe assembly 131 connected to one end of the top liquid cooling plate 120 can directly communicate with the bottom surface of one end of the top liquid cooling plate 120, without the need for the main pipe structure 130 to communicate with the top surface of the supporting liquid cooling plate 110 through the bent water nozzle 132, thereby reducing the space occupancy rate, and the end of the main pipe structure 130 communicating with the bottom surface of the top liquid cooling plate 120 can also provide support for the top liquid cooling plate 120 to maintain the stability of the cooling system structure.

[0036] In some embodiments, reference can be made to FIG. 10 to FIG. 13, FIG. 10 is a structural schematic diagram of the top liquid cooling plate 120 in FIG. 2, FIG. 11 is a top view of FIG. 10, FIG. 12 is a sectional view of FIG. 11, and FIG. 13 is an enlarged view of part B in FIG. 12. The top liquid cooling plate 120 is provided with a second flow channel 121 for flowing cooling medium, and the top liquid cooling plate 120 includes a base plate 122 and a connecting plate 123 connected to surround the second flow channel 121, 2≤H2 / T3≤3, 2.5≤H2 / T4≤3.75, wherein T3 is the thickness of the base plate 122, T4 is the thickness of the connecting plate 123, and H2 is the height of the second flow channel 121.

[0037] Specifically, the thickness T3 of the substrate 122 is usually designed to be 1-1.5 mm, the thickness T4 of the connecting plate 123 is usually designed to be 0.8-1.2 mm, and the thickness T3 of the substrate 122 needs to be greater than or equal to the thickness T4 of the connecting plate 123. Referring to the above description, the height H2 of the second flow channel 121 is usually 3 mm. If the ratio of the height H2 of the second flow channel 121 to the thickness T3 of the substrate 122 is less than 2, the height H2 of the second flow channel 121 is small, which may cause the cooling medium in the second flow channel 121 to fail to fully contact the heat source, thereby affecting the cooling effect of the top liquid cooling plate 120. At the same time, a too small flow channel height may require a higher precision manufacturing process, making the manufacturing more difficult. When the ratio of the height H2 of the second flow channel 121 to the thickness T3 of the substrate 122 is greater than 3, the thickness of the substrate 122 is relatively small and may not be able to withstand the relatively large pressure generated inside the flow channel, causing the substrate 122 to deform or break. At the same time, a too high flow channel height may cause the cooling medium to flow at a relatively slow speed due to the relatively large area of the flow channel, thereby reducing the cooling efficiency and affecting the heat dissipation effect.

[0038] If the ratio of the height H2 of the second flow channel 121 to the thickness T3 of the connecting plate 123 is less than 2.5, the height H2 of the second flow channel 121 is relatively small relative to the thickness T3 of the connecting plate 123, which limits the flow speed and flow rate of the cooling medium, resulting in poor cooling effect and increasing the manufacturing difficulty of the connecting plate 123. If the ratio of the height H2 of the second flow channel 121 to the thickness T3 of the connecting plate 123 is greater than 3.75, the height H2 of the second flow channel 121 is relatively large relative to the thickness T3 of the connecting plate 123, which may cause the structure to be damaged during the stamping manufacturing of the connecting plate 123, and also cause the cooling medium to flow at a relatively low speed due to the relatively large volume of the second flow channel 121, resulting in poor cooling effect.

[0039] In some embodiments, referring to FIGS. 6-9, FIG. 6 is a structural schematic view of the support liquid cooling plate 110 in FIG. 2, FIG. 7 is a top view of FIG. 6, FIG. 8 is a sectional view of FIG. 7, and FIG. 9 is an enlarged view of portion D in FIG. 8. The support liquid cooling plate 110 is provided with a first flow channel 111 for flowing cooling medium, the top liquid cooling plate 120 is provided with a second flow channel 121 (see FIG. 13) for flowing cooling medium, and the first flow channel 111 is connected to the second flow channel 121 through the pipe structure 130 to realize the transmission of the cooling medium. Among them, 0.4≤H1 / T1≤0.57, 0.52≤H2 / T2≤0.6, H1 is the height of the first flow channel 111, H2 is the height of the second flow channel 121, T1 is the thickness of the support liquid cooling plate 110, T2 is the thickness of the top liquid cooling plate 120, and the thickness T2 of the top liquid cooling plate 120 is equal to the sum of the thickness T3 of the substrate 122 and the thickness T4 of the connecting plate 123.

[0040] Specifically, referring to the above description, the height of the flow channel plate in the support cooling plate is usually designed to be 4 mm, that is, the first flow channel 111 height H1 is 4 mm, and the thickness of the support cooling plate is 7 mm to 10 mm. If the ratio of the first flow channel 111 height H1 to the support cooling plate thickness T1 is less than 0.4, at this time the height of the first flow channel 111 is lower, when the amount of cooling medium input into the support liquid cooling plate 110 per unit time is constant, it will cause the flow resistance of the cooling medium located in the first flow channel 111 to be too large, at the same time the manufacturing difficulty of the support liquid cooling plate 110 is higher. If the ratio of the first flow channel 111 height H1 to the support cooling plate thickness T1 is greater than 0.57, at this time the height of the first flow channel 111 is higher, which will cause the flow rate of the cooling medium located in the first flow channel 111 to be lower, and in the extreme case the cooling medium may not be able to fill the flow channel, resulting in poor cooling effect of the support liquid cooling plate 110. When the ratio of the first flow channel 111 height H1 to the support cooling plate thickness T1 is 0.4 to 0.57, at this time the manufacturing process of the support liquid cooling plate 110 is relatively simple, and at the same time the cooling effect of the support liquid cooling plate 110 is also better.

[0041] The thickness of the top liquid cooling plate 120 is usually designed to be 5 mm to 5.7 mm, and the second flow channel 121 height H2 is 3 mm. If the ratio of the second flow channel 121 height H2 to the top liquid cooling plate 120 thickness T2 is less than 0.52, at this time the height of the second flow channel 121 is lower, when the amount of cooling medium input into the top liquid cooling plate 120 per unit time is constant, it will cause the flow rate of the cooling medium located in the second flow channel 121 to be too fast, which may cause the cooling medium to be unable to fully contact the heat source, thereby affecting the cooling effect of the top liquid cooling plate 120. When the ratio of the second flow channel 121 height H2 to the top liquid cooling plate 120 thickness T2 is greater than 0.6, there is a risk of structural rupture in the stamping manufacturing process of the top liquid cooling plate 120, at the same time the height of the second flow channel 121 is higher, which will cause the flow rate of the cooling medium located in the second flow channel 121 to be lower, and the cooling effect of the top liquid cooling plate 120 is poorer. When the ratio of the second flow channel 121 height H2 to the top liquid cooling plate 120 thickness T2 is 0.52 to 0.6, at this time the cooling effect of the top liquid cooling plate 120 is better.

[0042] In some embodiments, referring to FIG. 9 and FIG. 13, 1.4≤T1 / T2≤2; wherein T1 is the thickness of the support liquid cooling plate 110, and T2 is the thickness of the top liquid cooling plate 120, the thickness T2 of the top liquid cooling plate 120 is equal to the sum of the thickness T3 of the base plate 122 and the thickness T4 of the connecting plate 123.

[0043] Specifically, the support liquid cooling plate 110 is generally composed of a bottom plate, a top plate and a flow channel plate between the bottom plate and the top plate. In order to ensure that the support liquid cooling plate 110 has sufficient strength to support the battery cell group 200, the thickness of the bottom plate and the top plate is designed to be not less than 1.5 mm and not more than 3 mm. The height of the flow channel plate in the support liquid cooling plate 110 will affect the flow rate and flow resistance of the cooling medium in the flow channel. When the amount of cooling medium input into the support liquid cooling plate 110 per unit time is constant, if the height of the flow channel plate is too high, the flow rate of the cooling medium in the flow channel will be low, thus the cooling effect of the support liquid cooling plate 110 will be poor. If the height of the flow channel plate is too low, the manufacturing difficulty of the support liquid cooling plate 110 will be high. In order to take into account the manufacturing difficulty of the flow channel plate and the flow rate of the cooling medium, the height of the flow channel plate is designed to be 4 mm. Therefore, the thickness T1 of the support liquid cooling plate 110 is 7 mm to 10 mm. The top liquid cooling plate 120 does not need to support the battery cell group 200, so its thickness is thinner than that of the support liquid cooling plate 110 to some extent. In order to ensure that the height of the flow channel in the top liquid cooling plate 120 meets the cooling function required, the thickness of the top liquid cooling plate 120 is designed to be not less than 5 mm.

[0044] If the ratio of the thickness T1 of the support liquid cooling plate 110 to the thickness T2 of the top liquid cooling plate 120 is less than 1.4, the thickness T1 of the support liquid cooling plate 110 is thin, and the manufacturing difficulty of the support liquid cooling plate 110 is high. If the ratio of the thickness T1 of the support liquid cooling plate 110 to the thickness T2 of the top liquid cooling plate 120 is greater than 2, the height of the flow channel in the support liquid cooling plate 110 is high, so the flow channel area is also large. When the amount of cooling medium input into the support liquid cooling plate 110 per unit time is constant, the flow rate of the cooling medium in the flow channel will be low, and the cooling effect of the support liquid cooling plate 110 will be poor. When the ratio of the thickness T1 of the support liquid cooling plate 110 to the thickness T2 of the top liquid cooling plate 120 is 1.4 to 2, the manufacturing process of the support liquid cooling plate 110 is relatively simple, and the cooling effect of the cooling system is also good.

[0045] In some embodiments, the support liquid cooling plate 110 is an extruded profile, and the top liquid cooling plate 120 is a punched profile. In this embodiment, the support liquid cooling plate 110 is set to an extruded profile in order to have a higher structural strength, so that when the support liquid cooling plate 110 supports the battery cell group 120, it can bear the weight of the battery cell group 120 to ensure that it is not damaged. The top liquid cooling plate 120 does not need to support the battery cell group 120, so it is set to a punched profile with lower strength to reduce production cost.

[0046] The application provides a liquid cooling system 100 for a battery pack, comprising at least one supporting liquid cooling plate 110 and a top liquid cooling plate 120, wherein each supporting liquid cooling plate 110 is used for supporting the bottom of a corresponding battery cell group 200 and cooling the battery cell group 200. The top liquid cooling plate 120 is located above the at least one supporting liquid cooling plate 110 and is used for abutting against the top of the battery cell group 200 supported on the supporting liquid cooling plate 110 close to the top liquid cooling plate 120 and also providing a cooling function for the battery cell group 200, and the thickness of the supporting liquid cooling plate 110 is greater than the thickness of the top liquid cooling plate 120. The liquid cooling system 100 can reduce the space occupancy of the liquid cooling plate and the battery cell group 200 through a laminated design, and on this basis, the thickness of the supporting liquid cooling plate 110 is set to be greater than the thickness of the top liquid cooling plate 120, so that the supporting liquid cooling plate 110 not only provides a cooling function for the battery cell group 200, but also ensures that the supporting liquid cooling plate 110 has sufficient strength to provide a supporting function for the battery cell group 200 to ensure the stability of the overall structure. Compared with the single-side cooling of the battery cell group 200 in the related art, the cooling system in the embodiment has higher heat dissipation efficiency, and the heat distribution of each battery cell group 200 is more uniform, that is, the temperature difference between the top and bottom of the battery cell group 200 is smaller, which can well ensure the safety of the battery cell group 200.

[0047] The application also provides a battery pack comprising the liquid cooling system 100. The battery pack has all the advantages of the liquid cooling system 100, which will not be repeated here.

[0048] The application also provides a power utilization device, which can be but is not limited to a pure electric vehicle and a hybrid electric vehicle. The power utilization device comprises a battery pack, which has all the advantages of the battery pack, which will not be repeated here.

Claims

1. A liquid cooling system for a battery pack, the battery pack comprising at least one cell assembly, wherein the liquid cooling system comprises: At least one supporting liquid cooling plate, each of the supporting liquid cooling plates being used to support the bottom of the corresponding battery cell assembly and to cool the battery cell assembly; as well as A top liquid cooling plate is located above at least one of the supporting liquid cooling plates and is used to abut against the top of the corresponding battery cell assembly and cool the battery cell assembly. The thickness of the supporting liquid cooling plate is greater than the thickness of the top liquid cooling plate.

2. The liquid cooling system according to claim 1, wherein, 1.4≤T1 / T2≤2; T1 is the thickness of the supporting liquid cooling plate, and T2 is the thickness of the top liquid cooling plate.

3. The liquid cooling system according to claim 2, wherein, The supporting liquid cooling plate is provided with a first flow channel for the flow of cooling medium, and the top liquid cooling plate is provided with a second flow channel for the flow of cooling medium, 0.4≤H1 / T1≤0.57, 0.52≤H2 / T2≤0.6; where H1 is the height of the first flow channel and H2 is the height of the second flow channel.

4. The liquid cooling system according to claim 1, wherein, The top liquid cooling plate is provided with a second flow channel for the flow of cooling medium. The top liquid cooling plate includes a base plate and a connecting plate. The base plate and the connecting plate are connected to form the second flow channel. 2≤H2 / T3≤3, 2.5≤H2 / T4≤3.75; where T3 is the thickness of the base plate, T4 is the thickness of the connecting plate, and H2 is the height of the second flow channel.

5. The liquid cooling system according to claim 1 further includes a piping structure, wherein the supporting liquid cooling plate is provided with a first flow channel for the flow of cooling medium, and the top liquid cooling plate is provided with a second flow channel for the flow of cooling medium, wherein the first flow channel is connected to the second flow channel through the piping structure.

6. The liquid cooling system according to claim 5, wherein the piping structure includes at least one main piping assembly and at least one water nozzle, one end of each water nozzle is connected to the second flow channel of the top liquid cooling plate through the corresponding main piping assembly, and the other end of each water nozzle is connected to the first flow channel of the corresponding supporting liquid cooling plate.

7. The liquid cooling system according to claim 6, wherein, The faucet is a one-piece molded structure.

8. The liquid cooling system according to claim 5, wherein, One end of the top liquid cooling plate extends beyond one end of at least one of the supporting liquid cooling plates in the length direction of the top liquid cooling plate; each of the main pipeline assemblies is connected to the bottom surface of the one end of the top liquid cooling plate and is also connected to the top surface of the one end of the corresponding supporting liquid cooling plate through the corresponding water nozzle.

9. The liquid cooling system according to claim 5, wherein, The piping structure also includes at least one through-wall connector, one end of each through-wall connector is connected to the corresponding main piping assembly, and the other end of the through-wall connector is used to pass through the side plate of the battery pack housing to connect to an external cooling medium source; the through-wall connector includes two abutting portions located on both sides of the side plate, and the two abutting portions abut against both sides of the side plate respectively.

10. The liquid cooling system according to claim 1, wherein, The supporting liquid cooling plate is an extruded profile.

11. The liquid cooling system according to claim 2, wherein, The top liquid cooling plate is made of stamped profile.

12. The liquid cooling system according to claim 2, wherein, The supporting liquid cooling plate includes a bottom plate, a top plate, and a flow channel plate located between the bottom plate and the top plate. The supporting liquid cooling plate satisfies the following conditions: the thickness of the bottom plate is 1.5mm to 3mm, the thickness of the top plate is 1.5mm to 3mm, and the thickness of the supporting liquid cooling plate is 7mm to 10mm.

13. The liquid cooling system according to claim 12, wherein, The thickness of the top liquid cooling plate is not less than 5 mm, and the thickness of the top liquid cooling plate is less than the thickness of the supporting liquid cooling plate.

14. A battery pack comprising a liquid cooling system as claimed in any one of claims 1-13.

15. An electrical appliance comprising the battery pack as claimed in claim 14.

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