Liquid cooling energy storage device

Abstract

The liquid cooling energy storage device comprises a box body, a plurality of battery packs and a cluster-level liquid supply pipeline extending along the height direction of the box body, and the plurality of battery packs are positioned in the box body and are stacked along the height direction of the box body; a plurality of liquid supply branch pipes are arranged on the cluster-level liquid supply pipeline at intervals in the height direction, and any liquid supply branch pipe is used for communicating the cluster-level liquid supply pipeline with a liquid inlet of a liquid cooling plate of one battery pack in the plurality of battery packs; and the position of the liquid inlet of the liquid cooling plate in the height direction is higher than the position of the joint of the liquid supply branch pipe and the cluster-level liquid supply pipeline. In the scheme, the position of the liquid inlet of the liquid cooling plate in the height direction is higher than the position of the joint of the liquid supply branch pipe and the cluster-level liquid supply pipeline, so that when the liquid cooling energy storage device replaces the cooling liquid, the cooling liquid of the liquid cooling plate in the battery pack can be discharged into the cluster-level liquid supply pipeline from the liquid inlet of the liquid cooling plate by utilizing the gravity of the cooling liquid; cooling liquid of the liquid cooling plate in the battery pack can be discharged completely, and the liquid changing proportion of the liquid cooling energy storage device is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid cooling fire fighting, in particular to a liquid cooling energy storage device. Background Art

[0002] In the energy storage device, the battery pack in the battery cluster is connected to the liquid supply pipe and the liquid return pipe, and the coolant circulates in the liquid supply pipe, the battery pack and the liquid return pipe. When the coolant flows into the battery pack, it can absorb and take away the heat of the battery pack in the energy storage device.

[0003] If the coolant stays in the battery pack for a long time, the pH value of the coolant will decrease, which can easily corrode the battery pack. The coolant needs to be replaced regularly.

[0004] In the current structure of energy storage devices, when the coolant in the battery pack is replaced, the original coolant in the battery pack is easily retained in the liquid cooling, which reduces the rate of replacement of the coolant in the energy storage device and has a negative impact on the liquid cooling effect of the energy storage device. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a liquid-cooled energy storage device which can improve the replacement ratio of coolant.

[0006] In the first aspect, the utility model provides a liquid-cooled energy storage device, a liquid-cooled energy storage device box, multiple battery packs and a cluster-level liquid supply pipeline extending along the height direction of the box, multiple battery packs are located in the box and stacked along the height direction of the box; the cluster-level liquid supply pipeline is provided with multiple liquid supply branches at intervals in the height direction, any liquid supply branch is used to connect the cluster-level liquid supply pipeline with the liquid inlet of a liquid cooling plate of one of the multiple battery packs; the position of the liquid inlet of the liquid cooling plate in the height direction is higher than the position of the connection between the liquid supply branch and the cluster-level liquid supply pipeline. In this scheme, since the position of the liquid inlet of the liquid cooling plate in the height direction is higher than the position of the connection between the liquid supply branch and the cluster-level liquid supply pipeline, when the liquid-cooled energy storage device replaces the coolant, the coolant of the liquid cooling plate in the battery pack can be discharged from the liquid inlet of the liquid cooling plate to the cluster-level liquid supply pipeline by its own gravity, which is conducive to the clean discharge of the coolant of the liquid cooling plate in the battery pack and improves the liquid replacement ratio of the liquid-cooled energy storage device.

[0007] In combination with the first aspect, in a possible implementation, the liquid-cooled energy storage device also includes a main-level liquid supply pipeline located below the cluster-level liquid supply pipeline, and the main-level liquid supply pipeline is connected to the cluster-level liquid supply pipeline. The coolant of the liquid-cooled energy storage device flows through the main-level liquid supply pipeline, the cluster-level liquid supply pipeline, and enters the liquid cooling plate of the battery pack to cool the battery pack. The main-level liquid supply pipeline is located below the cluster-level liquid supply pipeline, and the coolant supplies coolant to multiple battery packs from bottom to top. When the coolant of the liquid-cooled energy storage device is replaced, the coolant of multiple battery packs can use their own gravity to flow back into the main-level liquid supply pipeline from top to bottom, which is beneficial to drain the coolant of the liquid cooling plate in the battery pack and improve the liquid replacement ratio of the liquid-cooled energy storage device.

[0008] In combination with the first aspect, in a possible implementation, the main-stage liquid supply pipeline extends along the length direction of the box, the main-stage liquid supply pipeline is inclined relative to the horizontal plane, and the main-stage liquid supply pipeline is provided with a drain valve at the lower end of the two ends in the length direction of the box, and the cluster-level liquid supply pipeline is connected to the area between the two ends of the main-stage liquid supply pipeline. When the liquid-cooled energy storage device replaces the coolant, the drain valve is opened. Since the main-stage liquid supply pipeline is arranged below a plurality of battery packs, the coolant in the cluster-level liquid supply pipeline and the battery pack flows to the main-stage liquid supply pipeline. Since the drain valve is located at the other end of the main-stage liquid supply pipeline with a lower height, the coolant in the main-stage liquid supply pipeline flows toward the position of the drain valve, which is conducive to draining the coolant in the main-stage liquid supply pipeline and providing a liquid replacement ratio for the liquid-cooled energy storage device.

[0009] In combination with the first aspect, in a possible implementation, the main-stage liquid supply pipeline is inclined at a slope of 0.3%-1%, which can be beneficial for the liquid-cooled energy storage device to effectively discharge the coolant, and does not occupy a large space of the liquid-cooled energy storage device due to the excessive slope of the main-stage liquid supply pipeline. If the downward slope of the main-stage liquid supply pipeline is low (less than 0.3%), the coolant cannot effectively use its own gravity to flow to the location of the drain valve. If the downward slope of the main-stage liquid supply pipeline is high (greater than 1%), the main-stage liquid supply pipeline will occupy a larger height space of the box, which will have a negative impact on the energy density of the liquid-cooled energy storage device.

[0010] In combination with the first aspect, in a possible implementation, the liquid-cooled energy storage device further includes a cluster-level liquid return pipe, the cluster-level liquid return pipe extends along the height direction of the box, and the cluster-level liquid return pipe is provided with a plurality of liquid return branches at intervals in the height direction, and any liquid return branch is used to connect the cluster-level liquid return pipe with the liquid return port of a liquid cooling plate of a battery pack among the plurality of battery packs; in the height direction, the position of the connection between the liquid return branch and the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate. When the coolant circulates in the liquid-cooled energy storage device, if the coolant contains a large amount of gas, the cooling effect of the coolant cooling the battery pack will be reduced. In this solution, since the gas is light in texture, the gas mixed with the coolant will flow upward after entering the battery pack. In the height direction, the position of the connection between the liquid return branch and the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate, which is conducive to discharging the gas in the liquid cooling plate in the battery pack and improving the cooling effect of the coolant cooling the battery pack.

[0011] In combination with the first aspect, in a possible implementation, the liquid-cooled energy storage device further includes a main-level liquid return pipe disposed below the cluster-level liquid return pipe, and the main-level liquid return pipe is connected to the cluster-level liquid return pipe. Since the main-level liquid return pipe is disposed below the cluster-level liquid return pipe, when the liquid-cooled energy storage device replaces the coolant, the coolant of the liquid-cooled plates in multiple battery packs can flow through the liquid return branch pipe, the cluster-level liquid return pipe and the main-level liquid return pipe. During the process of the coolant of the liquid-cooled plates in the battery pack flowing through the liquid return branch pipe, the cluster-level liquid return pipe and the main-level liquid return pipe, the coolant flows roughly from top to bottom, so that the coolant can use its own gravity to flow from the liquid-cooled plates of the battery pack to the main-level liquid return pipe, which is beneficial to discharge the coolant of the liquid-cooled plates in the battery pack cleanly and improve the liquid replacement ratio of the liquid-cooled energy storage device.

[0012] In combination with the first aspect, in a possible implementation, the main-stage liquid return pipe extends along the length direction of the box, the main-stage liquid return pipe is inclined relative to the horizontal plane, and the main-stage liquid return pipe is provided with a drain valve at the lower end of the two ends in the length direction of the box, and the cluster-level liquid return pipe is connected to the area between the two ends of the main-stage liquid return pipe. When the liquid-cooled energy storage device replaces the coolant, the drain valve is opened. Since the main-stage liquid return pipe is arranged below a plurality of battery packs, the coolant in the cluster-level liquid return pipe and the battery pack flows to the main-stage liquid return pipe. Since the drain valve is located at the other end of the main-stage liquid return pipe with a lower height, the coolant in the main-stage liquid return pipe flows toward the position of the drain valve, which is conducive to draining the coolant in the main-stage liquid return pipe cleanly and providing a liquid replacement ratio for the liquid-cooled energy storage device.

[0013] In combination with the first aspect, in a possible implementation, the main-stage liquid return pipe has a slope of 0.3%-1%, which can be beneficial for the liquid-cooled energy storage device to effectively discharge the coolant, and will not occupy a large space of the liquid-cooled energy storage device due to the excessive slope of the main-stage liquid return pipe. If the downward slope of the main-stage liquid return pipe is low (less than 0.3%), the coolant's own gravity cannot be effectively utilized to flow to the location of the drain valve. If the downward slope of the main-stage liquid return pipe is high (greater than 1%), the main-stage liquid return pipe will occupy a larger height space of the box, which will have a negative impact on the energy density of the liquid-cooled energy storage device.

[0014] In combination with the first aspect, in a possible implementation, the cluster-level liquid supply pipeline is provided with a control valve for adjusting the flow of coolant; the liquid-cooled energy storage device is also provided with a sensor, the sensor is used to collect the temperature or water leakage of the battery pack, and the control valve is used to control the flow of coolant flowing through the cluster-level liquid supply pipeline according to the temperature or water leakage of the battery pack. The control valve can intelligently control the total flow of coolant cooling through multiple battery packs according to the temperature or water leakage of each battery pack. For example, if the temperature of the battery pack is too high, the flow of the cluster-level liquid supply pipeline can be increased through the control valve to increase the cooling force of the coolant cooling the battery pack to reduce the temperature of the battery pack. If the liquid cooling plate of the battery pack leaks coolant, the control valve can be automatically closed to stop supplying coolant to the battery pack, thereby avoiding continuous leakage of the battery pack and safety hazards (such as short circuit of the battery pack).

[0015] In combination with the first aspect, in a possible implementation, the cluster-level liquid return pipe is provided with a control valve for adjusting the flow of coolant; the liquid-cooled energy storage device is also provided with a sensor, the sensor is used to collect the temperature or water leakage of the battery pack, and the control valve is used to control the flow of coolant flowing through the cluster-level liquid return pipe according to the temperature or water leakage of the battery pack. The control valve can intelligently control the total flow of coolant cooling through multiple battery packs according to the temperature or water leakage of each battery pack. For example, if the temperature of the battery pack is too high, the flow of the cluster-level liquid return pipe can be increased through the control valve to increase the cooling force of the coolant cooling the battery pack to reduce the temperature of the battery pack. If the liquid cooling plate of the battery pack leaks coolant, the control valve can be automatically closed to stop supplying coolant to the battery pack, thereby avoiding continuous leakage of the battery pack and safety hazards (such as short circuit of the battery pack).

[0016] In a second aspect, the present application provides a liquid-cooled energy storage device, which includes a box body, multiple battery packs, a cluster-level liquid supply pipe and a cluster-level liquid return pipe, multiple battery packs are located in the box body and stacked along the height direction of the box body, the cluster-level liquid supply pipe extends along the height direction of the box body, and the cluster-level liquid supply pipe is provided with multiple liquid supply branches at intervals in the height direction, and any liquid supply branch is used to connect the cluster-level liquid supply pipe with a liquid inlet of a liquid cooling plate of one of the multiple battery packs; the cluster-level liquid return pipe extends along the height direction of the box body, and the cluster-level liquid return pipe is provided with multiple liquid return branches at intervals in the height direction, and any liquid return branch is used to connect the cluster-level liquid return pipe with the liquid return port of the liquid cooling plate of one of the multiple battery packs; in the height direction, the position of the connection between the liquid return branch and the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate. When the coolant circulates in the liquid-cooled energy storage device, if the coolant contains more gas, the cooling effect of the coolant cooling the battery pack will be reduced. In this solution, since the gas is lighter in texture, the gas mixed with the coolant will flow upward after entering the battery pack. In the height direction, the position of the connection between the return liquid branch pipe and the cluster-level return liquid pipe is higher than the position of the liquid inlet of the liquid cooling plate, which is beneficial to discharge the gas in the liquid cooling plate in the battery pack and improve the cooling effect of the coolant cooling the battery pack.

[0017] In combination with the second aspect, in a possible implementation, the position of the connection between the liquid return branch pipe and the cluster-level liquid return pipe is higher than the position of the liquid return port of the liquid cooling plate in the height direction. After the gas mixed with the coolant enters the battery pack, it will flow upward. The position of the connection between the liquid return branch pipe and the cluster-level liquid return pipe is higher than the position of the liquid return port of the liquid cooling plate in the height direction, which is also conducive to discharging the gas in the liquid cooling plate in the battery pack and improving the cooling effect of the coolant cooling the battery pack.

[0018] In combination with the second aspect, in a possible implementation, an exhaust valve is provided on the cluster-level liquid return pipe, and the position of the exhaust valve in the height direction is higher than the position where any of the liquid return branches are connected to the cluster-level liquid return pipe. When the coolant in the liquid-cooled energy storage device circulates, the gas mixed in the coolant will flow upward. In the height direction, the position where the liquid return branch is connected to the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate. The gas mixed with the coolant in the battery pack is more likely to be collected in the cluster-level liquid return pipe. In the height direction, the exhaust valve is provided on the cluster-level liquid return pipe at a position higher than the position where any of the liquid return branches are connected to the cluster-level liquid return pipe, which is beneficial for discharging the gas collected in the cluster-level liquid return pipe and improving the liquid cooling effect of the liquid-cooled energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the background technology, the drawings required for use in the embodiments of the utility model or the background technology will be described below.

[0020] Figure 1 A schematic diagram of the structure of an energy storage device provided by the utility model;

[0021] Figure 2 A front view of an energy storage device provided by the utility model;

[0022] Figure 3 A schematic diagram of the structure of the energy storage device provided by the utility model omitting the box and part of the battery;

[0023] Figure 4 A front view of the battery pack provided by the utility model;

[0024] Figure 5 A cross-sectional view of the battery pack provided by the utility model;

[0025] Figure 6 A schematic diagram of the structure of the energy storage device provided by the utility model omitting the battery cluster and liquid cooling pipeline;

[0026] Figure 7 A schematic diagram of the structure of the energy storage device provided by the utility model omitting the battery cluster and the liquid cooling unit;

[0027] Figure 8 This is a structural schematic diagram of the liquid cooling unit provided by the utility model.

[0028] Instruction manual drawings:

[0029] 1000, liquid-cooled energy storage device; 100, liquid cooling unit; 110, switch valve; 120, compressor; 130, condenser; 140, evaporator; 200, liquid cooling pipeline; 200a, drain valve; 200b, plug; 200c, control valve; 210, main-stage liquid supply pipeline; 220, cluster-level liquid supply pipeline; 230, main-stage liquid return pipeline; 240, cluster-level liquid return pipeline; 241, exhaust valve; 250, liquid supply branch pipe; 260, liquid return branch pipe; 300, battery cluster; 310, battery pack; 311, battery cell; 312, liquid cooling plate; 312a, liquid inlet; 312b, liquid return port; 313, shell; 400, box. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings.

[0031] Liquid-cooled energy storage devices play an important role in the process of renewable energy power generation (such as wind power generation, photovoltaic power generation, etc.). Liquid-cooled energy storage devices can stabilize the power generation system, provide energy backup, and improve the quality of electricity through the storage and release of energy, and have good application prospects. The liquid-cooled energy storage device may include a battery cluster and a power conversion unit. The battery cluster is used to store and release energy. The power conversion unit is used to convert the energy provided by the energy storage unit and provide it to the load. The power conversion unit can also convert the energy from the power grid or other power generation elements and provide it to the battery cluster. Here, the battery cluster may include various types of energy storage elements, such as lithium-ion batteries, lead-acid batteries (or lead-acid batteries) and other energy storage batteries (referred to as battery clusters in this utility model), and supercapacitors (also known as electrochemical capacitors), etc. The utility model does not specifically limit the specific type of battery clusters. The power conversion unit may include an energy storage converter (Power Control System, PCS) or a DC converter, etc. When the power conversion unit is an energy storage converter, the power conversion unit can realize the conversion of AC and DC in the charging or discharging process of the battery cluster. When a liquid-cooled energy storage device stores and releases electricity, the battery pack in the liquid-cooled energy storage device tends to generate heat. In a liquid-cooled energy storage device, the battery pack of the liquid-cooled energy storage device can be cooled by a coolant to reduce the negative impact of the heat generated by the battery pack on the battery pack itself.

[0032] At present, liquid-cooled energy storage devices are cooled by circulating coolant. If the coolant stays in the battery pack of the battery cluster for a long time, the pH value of the coolant will decrease, which will easily corrode the battery pack. The coolant needs to be replaced regularly, and the replacement ratio of the coolant affects the cooling effect of the subsequent new coolant on the battery pack in the liquid-cooled energy storage device. On the other hand, if the liquid-cooled energy storage device retains a lot of old coolant, the pH value of the mixed new and old coolant is still relatively low, and the coolant is highly acidic, which will still corrode the battery pack.

[0033] In view of this, the present application provides a liquid-cooled energy storage device capable of improving the cooling liquid replacement ratio. For ease of understanding, the length direction of the box is defined as the X-axis direction, the depth direction of the box is defined as the Y-axis direction, and the height direction of the box is defined as the Z-axis direction.

[0034] See also Figure 1 The liquid-cooled energy storage device 1000 includes a box 400, a liquid cooling unit 100, a liquid cooling pipeline 200 and a battery cluster 300. The battery clusters 300 are all accommodated in the box 400, and the battery cluster 300 includes a plurality of battery packs 310 (battery PACK) arranged along the height direction (Z-axis direction) of the box 400, and the plurality of battery packs 310 are connected in series or in parallel.

[0035] The liquid cooling pipeline 200 is housed in the housing 400. The liquid cooling pipeline 200 is used to connect the liquid cooling unit 100 and each battery pack 310 in the battery cluster 300. The liquid cooling pipeline 200 is used to circulate the coolant. Specifically, the coolant flows out of the liquid cooling unit 100, enters the liquid cooling pipeline 200, and then enters each battery pack 310 in the battery cluster 300 from the liquid cooling pipeline 200. The coolant entering each battery pack 310 in the battery cluster 300 absorbs the heat of each battery pack 310 and is discharged to the liquid cooling pipeline 200. The absorbed coolant enters the liquid cooling unit 100 from the liquid cooling pipeline 200. The liquid cooling unit 100 is used to cool the coolant after absorbing heat, and then discharges it to the liquid cooling pipeline 200, and the cycle continues. For details, please refer to Figure 2 The liquid cooling circuit 200 includes a main-level liquid supply pipeline 210, a cluster-level liquid supply pipeline 220, a main-level liquid return pipeline 230 and a cluster-level liquid return pipeline 240. The main-level liquid return pipeline 230 and the main-level liquid supply pipeline 210 are arranged below the battery cluster 300. The main-level liquid supply pipeline 210 is connected to the liquid cooling unit 100, and the cluster-level liquid supply pipeline 220 is connected to the main-level liquid supply pipeline 210; the cluster-level liquid supply pipeline 220 is connected to each battery pack 310 through a plurality of liquid supply branches 250. The coolant flows through the liquid cooling unit 100, the main liquid supply pipe 210, the cluster liquid supply pipe 220, the liquid supply branch pipe 250, and each battery pack 310 of the battery cluster 300 in sequence. Each battery pack 310 in the battery cluster 300 absorbs heat, and then flows through the liquid return branch pipe 260, the cluster liquid return pipe 240, and the main liquid return pipe 230, and returns to the liquid cooling unit 100. The liquid cooling unit 100 cools the coolant flowing in from the main liquid return pipe 230, and then discharges it to the main liquid supply pipe 210, and the cycle continues.

[0036] The liquid-cooled energy storage device 1000 circulates the coolant to absorb the heat of the liquid cooling plate 312 of the battery pack 310 in the battery cluster 300. During the circulation of the coolant in the liquid-cooled energy storage device 1000, the pH value of the coolant will decrease. The liquid cooling plate 312 of the battery pack 310 is generally made of metal. The coolant with a decreased pH value will corrode the liquid cooling plate 312, which may easily cause the liquid cooling plate 312 in the battery cluster 300 to leak the coolant. Regularly replacing the coolant in the liquid-cooled energy storage device 1000 can improve the situation where the coolant corrodes the liquid cooling plate 312 due to the decrease in pH value. The cycle for replacing the coolant in the liquid-cooled energy storage device 1000 is 3 years, 4 years, 5 years, 6 years, 7 years, etc. The utility model does not specifically limit the cycle for replacing the coolant in the liquid-cooled energy storage device 1000. During the process of replacing the coolant of the liquid-cooled energy storage device 1000 , if too much coolant is retained in the battery pack 310 in the battery cluster 300 (the liquid replacement ratio of the liquid-cooled energy storage device 1000 is low), the coolant retained in the battery pack 310 will still corrode the liquid cooling plate 312 of the battery pack 310 .

[0037] In this utility model, please see Figure 3 and Figure 4 The battery cluster 300 corresponds to a cluster-level liquid supply pipeline 220, wherein the cluster-level liquid supply pipeline 220 extends along the height direction of the box (Z-axis direction), and the cluster-level liquid supply pipeline 220 is provided with a plurality of liquid supply branch pipes 250 at intervals in the height direction, and any liquid supply branch pipe 250 is used to connect the cluster-level liquid supply pipeline 220 with the liquid inlet 312a of the liquid cooling plate 312 of a battery pack 310 among the plurality of battery packs 310. Since the liquid inlet 312a of the liquid cooling plate 312 is located higher than the connection between the liquid supply branch pipe 250 and the cluster-level liquid supply pipeline 220 in the height direction, when the liquid-cooled energy storage device 1000 replaces the coolant, the coolant of the liquid cooling plate 312 in the battery pack 310 can be discharged from the liquid inlet 312a of the liquid cooling plate 312 to the cluster-level liquid supply pipeline 220 by its own gravity, which is beneficial to drain the coolant of the liquid cooling plate 312 in the battery pack 310 and improve the liquid replacement ratio of the liquid-cooled energy storage device 1000.

[0038] The cluster-level liquid supply pipeline 220 is connected to the main-level liquid supply pipeline 210, and the main-level liquid supply pipeline 210 extends along the length direction (X-axis direction) of the box body 400. The main-level liquid supply pipeline 210 is arranged below the cluster-level liquid supply pipeline 220. Specifically, one end of the main-level liquid supply pipeline 210 is connected to the liquid cooling unit 100, and the other end thereof is provided with a drain valve 200a. The cluster-level liquid supply pipeline 220 is connected to the area between the two ends of the main-level liquid supply pipeline 210. The coolant of the liquid-cooled energy storage device 1000 flows through the main-level liquid supply pipeline 210 and the cluster-level liquid supply pipeline 220, and enters the liquid cooling plate 312 of the battery pack 310 to cool the battery pack 310. The main-level liquid supply pipeline 210 is located below the cluster-level liquid supply pipeline 220, and the coolant supplies coolant to multiple battery packs from bottom to top. When replacing the coolant of the liquid-cooled energy storage device 1000, the coolant of the multiple battery packs 310 can use its own gravity to flow back into the main liquid supply pipe 210 from top to bottom, which is beneficial to drain the coolant of the liquid cooling plate 312 in the battery pack 310 and improve the liquid replacement ratio of the liquid-cooled energy storage device 1000.

[0039] The main-stage liquid supply pipeline 210 is arranged at an inclination relative to the horizontal plane, and a drain valve 200a is arranged at the lower end of the main-stage liquid supply pipeline 210 in the length direction (X-axis direction) of the box 400. When the liquid-cooled energy storage device 1000 replaces the coolant, the drain valve 200a is opened. Since the main-stage liquid supply pipeline 210 is arranged below the multiple battery packs 310, the coolant in the cluster-stage liquid supply pipeline 220 and the battery pack 310 flows to the main-stage liquid supply pipeline 210. Since the drain valve 200a is located at the other end with a lower height between the two ends of the main-stage liquid supply pipeline 210, the coolant in the main-stage liquid supply pipeline 210 flows toward the position where the drain valve 200a is located, which is conducive to draining the coolant in the main-stage liquid supply pipeline 210 and providing a liquid replacement ratio for the liquid-cooled energy storage device 1000.

[0040] The primary liquid return pipe 230 extends along the length direction of the box (X-axis direction), one end of the primary liquid return pipe 230 is connected to the liquid cooling unit 100, and the other end of the primary liquid return pipe 230 is provided with a drain valve 200a. The primary liquid return pipe 230 is inclined relative to the horizontal plane, and the drain valve 200a is at the lower end of the two ends of the primary liquid return pipe 230 along the length direction (X-axis direction) of the box 400, and the cluster liquid return pipe 240 is connected to the area between the two ends of the primary liquid return pipe 230.

[0041] The cluster-level liquid return pipe 240 extends along the height direction (Z-axis direction) of the box body 400, and each cluster-level liquid return pipe 240 corresponds to a battery cluster 300. The cluster-level liquid return pipe 240 is provided with a plurality of liquid return branches 260 at intervals in the height direction, and any liquid return branch 260 is used to connect the cluster-level liquid return pipe 240 and the liquid return port 312b of the liquid cooling plate 312 of a battery pack 310 in a battery cluster 300.

[0042] The main-stage liquid return pipe 230 is located below the cluster-stage liquid return pipe 240. When the liquid-cooled energy storage device 1000 replaces the coolant, the coolant of the liquid cooling plates 312 in the multiple battery packs 310 can flow through the liquid return branch pipe 260, the cluster-stage liquid return pipe 240 and the main-stage liquid return pipe 230. During the process of the coolant of the liquid cooling plates 312 in the battery pack 310 flowing through the liquid return branch pipe 260, the cluster-stage liquid return pipe 240 and the main-stage liquid return pipe 230, the coolant flows roughly from top to bottom. In this way, the coolant can use its own gravity to flow from the liquid cooling plates 312 of the battery pack 310 to the main-stage liquid return pipe 230, which is beneficial to discharge the coolant of the liquid cooling plates in the battery pack and improve the liquid replacement ratio of the liquid-cooled energy storage device.

[0043] Since the cluster-level liquid return pipe 240 is connected to the area between the two ends of the main-level liquid return pipe 230, and the drain valve 200a is arranged at the lower end of the two ends of the main-level liquid return pipe 230, it can be obtained that the position of the main-level liquid return pipe 230 where the drain valve 200a is located is lower than the position where the cluster-level liquid return pipe 240 is connected to the main-level liquid return pipe 230. In this way, the coolant in the cluster-level liquid return pipe 240 can be conveniently discharged into the main-level liquid return pipe 230, and then discharged from the main-level liquid return pipe 230 to the outside of the main-level liquid return pipe through the drain valve 200a, which is conducive to discharging the coolant in the cluster-level liquid return pipe 240 and the main-level liquid return pipe 230 to the outside of the main-level liquid return pipe 230 through the drain valve 200a. Specifically, the main liquid return pipe 230 has a slope of 0.3%-1%, which can be beneficial for the liquid-cooled energy storage device 1000 to effectively discharge the coolant, and will not occupy a large space of the liquid-cooled energy storage device 1000 due to the excessive slope of the main liquid return pipe 230. If the main liquid return pipe 230 has a low downward slope (less than 0.3%), the coolant cannot effectively use its own gravity to flow to the location of the drain valve 200a. If the main liquid return pipe 230 has a high downward slope (greater than 1%), the main liquid return pipe 230 will occupy a large height space of the box 400, which will have a negative impact on the energy density of the liquid-cooled energy storage device 1000.

[0044] In the embodiment of the utility model, the position of the connection between the liquid return branch pipe 260 and the cluster-level liquid return pipe 240 in the height direction is higher than the position of the liquid return branch pipe 260 and the liquid return port 312b of the liquid cooling plate 312 in the battery pack. When the coolant circulates in the liquid-cooled energy storage device 1000, if the coolant contains a lot of gas, the cooling effect of the coolant cooling the battery pack 310 will be reduced. In this solution, since the gas is light in texture, the gas mixed with the coolant will flow upward after entering the battery pack 310. In the height direction, the position of the connection between the liquid return branch pipe 260 and the cluster-level liquid return pipe 240 is higher than the position of the liquid inlet 312a of the liquid cooling plate 312, which is conducive to discharging the gas in the liquid cooling plate 312 in the battery pack 310 and improving the cooling effect of the coolant cooling the battery pack 310.

[0045] In some embodiments, the position of the connection between the liquid return branch pipe 260 and the cluster-level liquid return pipe 240 in the height direction is higher than the position of the liquid return branch pipe 260 and the liquid return port 312b of the liquid cooling plate 312 in the battery pack 310. After the gas mixed with the coolant enters the battery pack 310, it will flow upward. The position of the connection between the liquid return branch pipe 260 and the cluster-level liquid return pipe 240 in the height direction is higher than the position of the liquid return port 312b of the liquid cooling plate 312, which is also conducive to discharging the gas in the liquid cooling plate 312 in the battery pack 310, thereby improving the cooling effect of the coolant cooling the battery pack 310.

[0046] The liquid inlet 312a and the liquid return port 312b of the liquid cooling plate 312 are both connected to the flow channel of the liquid cooling plate 312. For the same battery pack 310, the position of the liquid inlet 312a can be higher than the position of the liquid return port 312b, or the position of the liquid inlet 312a can be lower than the position of the liquid return port 312b, or the height of the liquid inlet 312a can be consistent with the height of the liquid return port 312b.

[0047] The cluster-level liquid return pipe 240 is also provided with an exhaust valve 241, and the position of the exhaust valve 241 in the height direction is higher than the position where any of the liquid return branches 260 are connected to the cluster-level liquid return pipe 240. When the coolant in the liquid-cooled energy storage device 1000 circulates, the gas mixed in the coolant will flow upward. In the height direction, the position where the liquid return branch 260 is connected to the cluster-level liquid return pipe 240 is higher than the position of the liquid inlet 312a of the liquid cooling plate 312. The gas mixed with the coolant in the battery pack 310 is more likely to be collected in the cluster-level liquid return pipe 240. In the height direction, the exhaust valve 241 is provided in the cluster-level liquid return pipe 240 at a position higher than the position where any of the liquid return branches 260 are connected to the cluster-level liquid return pipe 240, which is conducive to discharging the gas collected in the cluster-level liquid return pipe 240 and improving the liquid cooling effect of the liquid-cooled energy storage device 1000. Specifically, the exhaust valve 241 may be disposed at the top of the cluster-level liquid return pipe 240 .

[0048] Please go further Figure 4 and Figure 5Each battery pack 310 may include a shell 313, a battery cell 311 and a liquid cooling plate 312. The battery cell 311 and the liquid cooling plate 312 are accommodated in the shell 313. The battery cell 311 and the liquid cooling plate 312 are stacked in the vertical direction. The battery cell 311 is in contact with the liquid cooling plate 312 and is located above the liquid cooling plate 312. The liquid cooling plate 312 is in contact with the battery cell 311. The liquid cooling plate 312 has a liquid inlet and a liquid return port, and the liquid inlet and the liquid return port are both arranged on the outer side of the shell. The battery pack and the liquid cooling pipeline are arranged along the depth direction of the box body, and the liquid inlet and the liquid return port are arranged on an outer side of the battery pack facing the liquid cooling pipeline. The liquid inlet 312a and the liquid return port are both connected to the flow channel of the liquid cooling plate 312. The liquid inlet 312a is connected to the liquid supply branch pipe 250, and the liquid return port is connected to the liquid return branch pipe. When the coolant cools the battery pack 310, the coolant flows from the liquid supply branch pipe 250 through the liquid inlet 312a, and then enters the flow channel of the liquid cooling plate 312 from the liquid inlet 312a. Since the liquid cooling plate 312 is in contact with the battery cell 311, the coolant entering the flow channel of the liquid cooling plate 312 can absorb the heat of the battery cell 311, thereby reducing the temperature of the battery pack 310. The coolant that enters the liquid cooling plate in the battery pack from the liquid inlet flows in the flow channel of the liquid cooling plate, and flows out from the return liquid port of the liquid cooling plate to the return liquid branch pipe. The coolant absorbs the heat of the battery cell during the flow in the flow channel of the liquid cooling plate. It should be noted that the battery cell 311 is the main heat source of the battery pack 310. By absorbing the temperature of the battery cell 311 in the battery pack 310 by the coolant, the temperature of the battery pack 310 can be effectively reduced. The coolant can be water, which has a high specific heat capacity. In a cycle in which the coolant circulates to cool the battery pack 310 in the battery cluster 300 , using water as the coolant can absorb more heat from the battery pack 310 , thus achieving a better cooling effect.

[0049] See also Figure 6 and Figure 7The liquid cooling unit 100 is housed in the box body 400, and the box body 400 can be divided into multiple areas, and the multiple areas are arranged in sequence along the width direction of the box body 400. One of the areas is used to accommodate the liquid cooling unit 100, and the remaining areas are used to accommodate the battery clusters 300. All areas for accommodating the battery clusters 300 are located on one side of the area for accommodating the liquid cooling unit 100 along the length direction (X-axis direction) of the box body 400. In order to facilitate the circulation of liquid supply for the battery packs 310 of each battery cluster 300, multiple cluster-level liquid supply pipes 220 are arranged at intervals along the width direction of the box body 400; cluster-level liquid return pipes 240 are arranged at intervals along the length direction (X-axis direction) of the box body 400. It can be understood that when the coolant is supplying liquid to the battery pack 310 of the battery cluster 300, the coolant is supplied to the battery pack 310 of each battery cluster 300 from left to right roughly along the length direction of the box (positive direction of the X axis), and the coolant in the battery pack 310 of each battery cluster 300 is returned to the liquid cooling unit 100 roughly from right to left along the length direction of the box 400 (negative direction of the X axis). The reversing node positions in the electrolyte circulation process will be relatively small, which can save the reversing components required for the liquid cooling pipeline 200, reduce the space occupied by the reversing components in the liquid-cooled energy storage device 1000, and improve the energy density of the liquid-cooled energy storage device 1000. The reversing node positions in the electrolyte circulation process are relatively small, which can also reduce the flow resistance of the coolant during the circulation flow, reduce the cycle of the coolant circulation flow, and improve the cooling efficiency of the battery pack 310 in the liquid-cooled battery cluster 300.

[0050] Specifically, there are multiple cluster-level liquid supply pipes 220, which are arranged at intervals along the width direction of the box body 400, and the multiple cluster-level liquid supply pipes 220 correspond to the number of multiple battery clusters 300. There are multiple cluster-level liquid return pipes 240, which are arranged at intervals along the width direction of the box body 400, and the multiple cluster-level liquid return pipes 240 correspond to the multiple battery clusters 300. Each main-level liquid supply pipe 210 supplies coolant to multiple battery clusters 300 through multiple cluster-level liquid supply pipes 220, and multiple battery clusters 300 return liquid to the cluster-level liquid return pipes 240 through multiple cluster-level liquid return pipes 240. The plurality of battery clusters 300 are arranged in sequence along the width direction of the box 400, the plurality of cluster-level liquid supply pipes 220 are arranged at intervals along the width direction of the box 400, and the plurality of cluster-level liquid return pipes 240 are arranged at intervals along the length direction (X-axis direction) of the box 400, so that the layout of the liquid cooling pipeline 200 and the battery cluster 300 of the liquid-cooled energy storage device 1000 is more regular, which is conducive to improving the energy density of the liquid-cooled energy storage device 1000. Among them, the number of battery clusters 300 can be 1, 2, 3, 4, 5, 6, etc., and the utility model does not specifically limit the number of battery clusters 300.

[0051] See also Figure 8In the embodiment provided by the utility model, the liquid cooling unit 100 may include a compressor 120, a condenser 130 and an evaporator 140. The outlet of the compressor 120 is connected to the inlet of the condenser 130, the outlet of the condenser 130 is connected to the inlet of the evaporator 140, and the outlet of the evaporator 140 is connected to the inlet of the compressor 120. The compressor 120 can compress the heat exchange medium and transport the compressed heat exchange medium to the condenser 130. The condenser 130 condenses the heat exchange medium to liquefy the heat exchange medium. The liquefied heat exchange medium enters the evaporator 140. The evaporator 140 evaporates the liquefied heat exchange medium to vaporize the liquid heat exchange medium. The heat exchange medium vaporized by the evaporator 140 is then transported to the compressor 120, and the cycle is repeated. The heat exchange medium may be Freon. In the liquid cooling unit 100, the evaporator 140 can absorb the heat of the coolant entering the liquid cooling unit 100 when evaporating the heat exchange medium to reduce the temperature of the coolant. It should be noted that an exhaust valve 241 is provided in the liquid cooling unit 100. During the process of the coolant in the main liquid return pipe 230 being discharged to the liquid cooling unit 100, the gas present in the coolant can be discharged to the outside of the liquid cooling unit 100 through the exhaust valve 241. By removing the gas in the coolant, it is helpful to improve the effect of the coolant cooling the battery cells 311 in the battery cluster 300.

[0052] In the embodiment provided by the utility model, the liquid cooling unit 100 is provided with a switch valve 110, which can control the connection between the main-stage liquid supply pipeline 210 and the liquid cooling unit 100, and the switch valve 110 can be a butterfly valve. When the switch valve 110 is opened, the main-stage liquid supply pipeline 210 is connected to the liquid cooling unit 100, and the main-stage liquid supply pipeline 210 and the liquid cooling unit 100 can communicate with each other. When the switch valve 110 is closed, the main-stage liquid supply pipeline 210 is not connected to the liquid cooling unit 100, and the coolant in the liquid cooling unit 100 cannot flow into the main-stage liquid supply pipeline 210. The liquid cooling unit 100 is also provided with a switch valve 110, which can control the connection between the main-stage liquid return pipeline 230 and the liquid cooling unit 100, and the switch valve 110 can be a butterfly valve. When the switch valve 110 is opened, the primary liquid return pipe 230 is connected to the liquid cooling unit 100, and the primary liquid return pipe 230 and the liquid cooling unit 100 can communicate with each other. When the switch valve 110 is closed, the primary liquid return pipe 230 is not connected to the liquid cooling unit 100, and the coolant in the primary liquid return pipe 230 cannot flow into the liquid cooling unit 100.

[0053] The primary liquid supply pipe 210 is provided with a plug 200b, which is disposed at a port of the primary liquid supply pipe 210 away from the liquid cooling unit, and is used to block the port of the primary liquid supply pipe 210 away from the liquid cooling unit 100. The plug 200b blocks the port of the primary liquid supply pipe 210 away from the liquid cooling unit 100, which can prevent dust and impurities from entering the primary liquid supply pipe 210, and reduce the probability of dust and impurities entering the coolant, thereby affecting the effect of the coolant cooling the liquid cold plate 312 cooling the battery cell 311.

[0054] The primary liquid return pipe 230 is provided with a plug 200b, which is used to block the port of the primary liquid return pipe 230 away from the liquid cooling unit 100. The plug 200b is arranged at the port of the primary liquid return pipe 230 away from the liquid cooling unit 100. The plug can prevent dust and impurities from entering the primary liquid return pipe 230, and reduce the probability of dust and impurities entering the coolant, thereby affecting the effect of the coolant cooling the liquid cold plate 312 cooling the battery cell 311.

[0055] In the embodiment provided by the utility model, each of the multiple cluster-level liquid supply pipelines 220 is provided with a control valve 200c, or each of the multiple cluster-level liquid return pipelines 240 is provided with a control valve 200c. The control valve 200c can adjust the flow rate, and the control valve 200c can be an electric regulating valve. When the flow rate of the control valve 200c is zero, the control valve 200c is in a closed state. The control valve 200c controls the flow rate of the cluster-level liquid supply pipeline 220 in which it is located, or the control valve 200c controls the flow rate of the cluster-level liquid return pipeline 240 in which it is located. Exemplarily, when there is a battery cluster 300 with a high temperature in the liquid-cooled energy storage device 1000, the control valve 200c is used to increase the flow rate of the coolant flowing through the cluster-level liquid supply pipeline 220 or the cluster-level liquid return pipeline 240 corresponding to the battery cluster 300, so as to improve the cooling effect of the liquid cooling plate 312 in the battery cluster 300 and reduce the temperature of the battery cluster 300. If the temperature of a battery cluster 300 in the liquid-cooled energy storage device 1000 is low, the flow rate of the coolant flowing through the cluster-level liquid supply pipe 220 or the cluster-level liquid return pipe 240 of the battery cluster 300 can be reduced by the control valve 200c, or the control valve 200c can be closed to make the flow rate of the coolant flowing through the cluster-level liquid supply pipe 220 or the cluster-level liquid return pipe 240 of the battery cluster 300 zero.

[0056] In the embodiment provided by the utility model, the liquid-cooled energy storage device 1000 is also provided with sensors, and the number of sensors may be multiple, some of the sensors may be temperature sensors, and some of the sensors may be water immersion sensors. The temperature sensor can collect the temperature of the battery cluster 300, and the water immersion sensor can collect whether the battery cluster 300 is leaking. Among them, the water immersion sensor can be arranged on the main-level return liquid pipeline or / and the main-level supply liquid pipeline. The control valve 200c can control the flow rate of the coolant flowing through the cluster-level return liquid pipeline 240 or the cluster-level supply liquid pipeline 220 corresponding to the battery cluster 300 according to the temperature of the battery cluster 300 collected by the temperature sensor. The control valve 200c can control the flow rate of the coolant flowing through the cluster-level return liquid pipeline 240 or the cluster-level supply liquid pipeline 220 corresponding to the battery cluster 300 according to the water leakage of each battery cluster 300 collected by the water immersion sensor.

[0057] In some embodiments, the flow rate of the coolant flowing through each control valve 200c can be remotely controlled by the terminal. For example, taking the temperature of a battery cluster 300 collected by the temperature sensor as an example, the temperature sensor sends the collected temperature of the battery cluster 300 to the terminal, and the terminal sends a control instruction to the control valve 200c according to the received temperature to control the opening of the control valve 200c, thereby controlling the flow rate of the coolant flowing through the cluster-level liquid return pipe 240 or the cluster-level liquid supply pipe 220 corresponding to the battery cluster 300. It should be noted that if the temperature of the battery cluster 300 is greater than the preset threshold, the terminal sends a control instruction to increase the opening of the control valve 200c to increase the flow rate of the cluster-level liquid supply pipe 220 or the cluster-level liquid return pipe 240 corresponding to the battery cluster 300.

[0058] Taking the case where the water immersion sensor collects the water leakage of a battery cluster 300 as an example, the water immersion sensor sends the collected water leakage of the battery cluster 300 to the terminal, and the terminal sends a control instruction to the control valve 200c according to the received water leakage to control the opening of the control valve 200c, thereby controlling the flow rate of the coolant flowing through the cluster-level liquid return pipe 240 or the cluster-level liquid supply pipe 220 corresponding to the battery valve. It should be noted that if there is a water leakage in the battery cluster 300, the terminal sends a control instruction to reduce the opening of the control valve 200c or close the control valve 200c, reduce the flow rate of the coolant flowing through the cluster-level liquid return pipe 240 or the cluster-level liquid supply pipe 220 corresponding to the battery cluster 300, or make the coolant flowing through the cluster-level liquid return pipe 240 and the cluster-level liquid supply pipe 220 corresponding to the battery cluster 300 zero, and by stopping the supply of coolant to the battery cluster 300, avoid the battery cluster 300 from continuously leaking and causing safety hazards (such as short circuit of the battery cluster 300).

[0059] In the embodiment provided by the utility model, each battery cluster 300 is provided with a floor drain. If the liquid cooling plate 312 in a battery cluster 300 leaks coolant, the floor drain in the battery cluster 300 can discharge the leaked coolant from the liquid cooling plate 312 to the outside of the battery cluster 300, thereby reducing the risk of short circuit of the battery cluster 300 caused by leakage of the liquid cooling plate 312 in the battery cluster 300.

[0060] The first, second, third, fourth and various numerical numbers involved in this article are only distinguished for the convenience of description and are not used to limit the scope of the present utility model.

[0061] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid-cooled energy storage device, It is characterized in that The energy storage device comprises: Box; A plurality of battery packs located in the box and stacked along the height direction of the box; A cluster-level liquid supply pipeline extends along the height direction of the box body, and the cluster-level liquid supply pipeline is provided with a plurality of liquid supply branches at intervals in the height direction, and any liquid supply branch is used to connect the cluster-level liquid supply pipeline with the liquid inlet of a liquid cooling plate of a battery pack among the plurality of battery packs; in the height direction, the position of the liquid inlet of the liquid cooling plate is higher than the position of the connection between the liquid supply branch and the cluster-level liquid supply pipeline.

2. The liquid-cooled energy storage device according to claim 1, It is characterized in that The liquid-cooled energy storage device further includes a main-level liquid supply pipeline located below the cluster-level liquid supply pipeline, and the main-level liquid supply pipeline is in communication with the cluster-level liquid supply pipeline.

3. The liquid-cooled energy storage device according to claim 2, It is characterized in that The main-stage liquid supply pipeline extends along the length direction of the box body, and is arranged to be inclined relative to the horizontal plane. A drain valve is provided at the lower end of the main-stage liquid supply pipeline in the length direction of the box body, and the cluster-stage liquid supply pipeline is connected to the area between the two ends of the main-stage liquid supply pipeline.

4. The liquid-cooled energy storage device according to claim 3, It is characterized in that The main-stage liquid supply pipeline has an inclination gradient of 0.3%-1%.

5. The liquid-cooled energy storage device according to any one of claims 1 to 4, It is characterized in that The liquid-cooled energy storage device also includes a cluster-level liquid return pipe, which extends along the height direction of the box body. The cluster-level liquid return pipe is provided with a plurality of liquid return branches at intervals in the height direction, and any liquid return branch is used to connect the cluster-level liquid return pipe with the liquid return port of a liquid cooling plate of a battery pack among the plurality of battery packs; in the height direction, the position of the connection between the liquid return branch and the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate.

6. The liquid-cooled energy storage device according to claim 5, It is characterized in that The liquid-cooled energy storage device further includes a main-level liquid return pipe disposed below the cluster-level liquid return pipe, and the main-level liquid return pipe is in communication with the cluster-level liquid return pipe.

7. The liquid-cooled energy storage device according to claim 6, It is characterized in that The main-stage liquid return pipe extends along the length direction of the box body, and the main-stage liquid return pipe is inclined relative to the horizontal plane. The main-stage liquid return pipe is provided with a drain valve at the lower end of the two ends in the length direction of the box body, and the cluster-stage liquid return pipe is connected to the area between the two ends of the main-stage liquid return pipe.

8. The liquid-cooled energy storage device according to claim 7, It is characterized in that The slope of the primary liquid return pipeline is 0.3%-1%.

9. The liquid-cooled energy storage device according to claim 1, It is characterized in that The cluster-level liquid supply pipeline is provided with a control valve for adjusting the flow rate of coolant; the liquid-cooled energy storage device is also provided with a sensor, which is used to collect the temperature or water leakage of the battery pack, and the control valve is used to control the flow rate of coolant flowing through the cluster-level liquid supply pipeline according to the temperature or water leakage of the battery pack.

10. The liquid-cooled energy storage device according to claim 5, It is characterized in that The cluster-level liquid return pipe is provided with a control valve for adjusting the flow rate of the coolant; the liquid-cooled energy storage device is also provided with a sensor, the sensor is used to collect the temperature or water leakage of the battery pack, and the control valve is used to control the flow rate of the coolant flowing through the cluster-level liquid return pipe according to the temperature or water leakage of the battery pack.

11. A liquid-cooled energy storage device, It is characterized in that include: Box; A plurality of battery packs located in the box and stacked along the height direction of the box; a cluster-level liquid supply pipeline extending in the height direction of the box body, wherein the cluster-level liquid supply pipeline is provided with a plurality of liquid supply branches at intervals in the height direction, and any liquid supply branch is used to connect the cluster-level liquid supply pipeline with a liquid inlet of a liquid cooling plate of one of the plurality of battery packs; A cluster-level liquid return pipe extends along the height direction of the box body, and the cluster-level liquid return pipe is provided with a plurality of liquid return branches at intervals in the height direction, and any liquid return branch is used to connect the cluster-level liquid return pipe with the liquid return port of a liquid cooling plate of a battery pack among the plurality of battery packs; in the height direction, the position of the connection between the liquid return branch and the cluster-level liquid return pipe is higher than the position of the liquid inlet of the liquid cooling plate.

12. The liquid-cooled energy storage device according to claim 11, It is characterized in that In the height direction, the position of the connection between the liquid return branch pipe and the cluster-level liquid return pipe is higher than the position of the liquid return port of the liquid cooling plate.

13. The liquid-cooled energy storage device according to claim 11 or 12, It is characterized in that The cluster-level liquid return pipe is provided with an exhaust valve, and the position of the exhaust valve in the height direction is higher than the position where any of the liquid return branches is connected to the cluster-level liquid return pipe.

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