Energy storage device, energy storage system, and liquid cooling control method for battery packs of energy storage device

Abstract

Provided in the embodiments of the present application are an energy storage device, an energy storage system, and a liquid cooling control method for battery packs of the energy storage device. The energy storage device comprises a plurality of battery packs, an input main line, a plurality of input branches, an output main line and a plurality of output branches. Each of the plurality of battery packs comprises a liquid inlet and a liquid outlet; the plurality of input branches are communicated with the input main line; the plurality of output branches are communicated with the output main line. The plurality of input branches are communicated with the liquid inlets of the plurality of battery packs on a one-to-one basis, and the plurality of output branches are communicated with the liquid outlets of the plurality of battery packs on a one-to-one basis. The energy storage device further comprises series branches and control valves, one end of each series branch being communicated with the liquid outlet of one battery pack, and the other end of the series branch being communicated with the liquid inlet of another battery pack; each control valve is used for controlling switching between series connection and parallel connection of one battery pack and another battery pack. The energy storage device of the present application can effectively suppress thermal runaway of battery packs.

Description

Energy storage device, energy storage system, and liquid cooling control method for battery pack of energy storage device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 27, 2023, with application number 202311834218.2 and application name “Energy storage device, energy storage system and liquid cooling control method of battery pack of energy storage device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of energy storage equipment, and in particular to an energy storage device, an energy storage system, and a liquid cooling control method for a battery pack of the energy storage device. Background Art

[0003] Energy storage devices in related technologies generally use a cold plate heat dissipation method to indirectly and continuously remove heat generated by the battery pack through the cold plate. For battery packs using immersion heat dissipation, heat generated by the battery pack is removed through the flow of immersion liquid. However, under normal operating conditions, in order to reduce system flow resistance and power consumption, the flow rate of the liquid cooling medium input into the battery pack or the cold plate of the battery pack is lower than that during thermal runaway. As a result, neither cold plate heat dissipation nor immersion heat dissipation can be effectively suppressed during thermal runaway of the battery pack.

[0004] Application Contents

[0005] Embodiments of the present application provide an energy storage device, an energy storage system, and a liquid cooling control method for a battery pack of the energy storage device to solve the problem that thermal runaway of a battery pack cannot be effectively suppressed.

[0006] In the first aspect, an embodiment of the present application provides an energy storage device, comprising a plurality of battery packs, an input main line, a plurality of input branches, an output main line and an output branch, wherein the plurality of battery packs each include a liquid inlet and a liquid outlet, the plurality of input branches each are connected to the input main line, the plurality of output branches each are connected to the output main line, the plurality of input branches are connected one-to-one with the liquid inlets of the plurality of battery packs, and the plurality of output branches are connected one-to-one with the liquid outlets of the plurality of battery packs. Since each of the plurality of battery packs can receive a liquid cooling medium through the input branch and the input main line to exchange heat with the battery cells in the battery pack to cool the battery cells in the battery pack. Each battery pack can also transport the liquid cooling medium that has absorbed the heat of the battery cells to the outside through the output branch and the output main line to exchange heat with the external refrigerant and transfer the heat to the refrigerant. Such a cycle can effectively dissipate heat and cool the plurality of battery packs.

[0007] The energy storage device also includes a series branch and a control valve. One end of the series branch is connected to the liquid outlet of one battery pack, and the other end of the series branch is connected to the liquid inlet of another battery pack. The control valve is used to control the switching between series and parallel connection of one battery pack and the other battery pack.

[0008] In this embodiment, when multiple battery packs are operating normally, control valves can be used to control one battery pack to be connected in parallel with another battery pack to the input and output main trunks. This effectively reduces flow resistance and energy consumption. If at least one of the multiple battery packs experiences thermal runaway, control valves can be used to control one battery pack to be connected in series with another battery pack to the input and output main trunks. This effectively increases the flow of liquid cooling medium into the battery pack experiencing thermal runaway. The specific reason for the increase in the flow rate of the liquid-cooling medium flowing into the battery pack with thermal runaway is that since one battery pack and another battery pack are connected to the input main line and the output main line in a series arrangement, the input branch between the liquid inlet of the other battery pack and the input main line is disconnected, so that the input branch connected to the battery pack no longer diverts the input main line, and the flow rate from the input main line to other input branches becomes larger, and the flow rate of the liquid-cooling medium flowing to other battery packs is increased, and the other battery pack inputs the liquid-cooling medium through a battery pack connected in series with it. At this time, the heat dissipation performance of each battery pack is improved, so as to effectively suppress the battery pack with thermal runaway.

[0009] In some embodiments, when thermal runaway occurs in another battery pack, a control valve is used to disconnect an output branch connected to the liquid outlet of one battery pack from the main output circuit while controlling the series branch circuit to connect the liquid outlet of one battery pack to the liquid inlet of another battery pack. In this embodiment, when thermal runaway occurs in another battery pack, the control valve controls the liquid outlet of one battery pack to connect to the liquid inlet of the other battery pack in series via the series branch circuit, allowing liquid cooling fluid flowing out of the liquid outlet of one battery pack to enter the other battery pack. Simultaneously, liquid cooling fluid can also be input into the other battery pack via the input branch circuit connected to the other battery pack, thereby increasing the flow rate of liquid cooling fluid input into the other battery pack, thereby effectively suppressing the battery pack experiencing thermal runaway.

[0010] In some embodiments, when thermal runaway occurs in at least one battery pack, a control valve is used to control the state in which the series branch connects the liquid outlet of one battery pack and the liquid inlet of another battery pack, thereby disconnecting an output branch connected to the liquid outlet of one battery pack from the output main trunk, and disconnecting an input branch connected to the liquid inlet of the other battery pack from the input main trunk. In this embodiment, because the control valve controls the state in which the series branch connects the liquid outlet of one battery pack and the liquid inlet of the other battery pack connects the liquid outlet of one battery pack and the liquid inlet of the other battery pack, disconnecting an output branch connected to the liquid outlet of one battery pack from the output main trunk, and disconnecting an input branch connected to the liquid inlet of the other battery pack from the input main trunk, one battery pack and another battery pack are arranged in series, and the input branch connected to the other battery pack no longer diverts flow from the input main trunk. This increases the flow rate from the input main trunk to the other input branches, thereby increasing the flow rate of the liquid cooling medium to the other battery packs. At this time, the heat dissipation performance of each battery pack is improved, effectively suppressing the battery pack from thermal runaway.

[0011] In some embodiments, while the control valve is used to control the series branch circuit to connect the liquid outlet of one battery pack to the liquid inlet of another battery pack and disconnect the output branch circuit between the liquid outlet of one battery pack and the output main trunk circuit, the control valve also controls the disconnection of the input branch circuit between the liquid inlet of another battery pack and the input main trunk circuit. In this embodiment, because the control valve also controls the disconnection of the input branch circuit between the liquid inlet of another battery pack and the input main trunk circuit, the input branch connected to the battery pack no longer diverts flow from the input main trunk circuit, increasing the flow rate from the input main trunk circuit to other input branches, thereby increasing the flow rate to other battery packs. Furthermore, the other battery pack whose liquid inlet is not connected to the input main trunk circuit can also flow liquid cooling medium through the series branch circuit, and the flow rate of the liquid cooling medium flowing in is the same as the flow rate from other input branches to other battery packs. Thus, the flow rate is improved, and the heat dissipation performance of each battery pack is improved.

[0012] In some embodiments, while the control valve is used to control the series branch circuit to connect the liquid outlet of one battery pack with the liquid inlet of another battery pack and disconnect the output branch circuit between the liquid outlet of one battery pack and the output main trunk, the input branch circuit between the liquid inlet of the other battery pack and the input main trunk circuit remains connected. In this embodiment, the other battery pack not only receives liquid cooling fluid from the one battery pack whose output branch circuit between the liquid outlet and the output main trunk circuit is disconnected, but also receives liquid cooling fluid flowing into the input branch circuit, thereby increasing the flow rate of the other battery pack and improving the heat dissipation performance of the other battery pack.

[0013] In some embodiments, the control valve includes multiple multi-way valves. A multi-way valve is provided on an output branch connected to the liquid outlet of one battery pack, and another multi-way valve is provided on an input branch connected to the liquid inlet of another battery pack. One end of the series branch is connected to one multi-way valve, and the other end of the series branch is connected to another multi-way valve. The multi-way valves are used to control the switching between series and parallel connection of one battery pack and another battery pack. In this embodiment, because one end of the series branch is connected to one multi-way valve and the other end of the series branch is connected to another multi-way valve, one multi-way valve controls the connection between the liquid outlet of one battery pack and one end of the series branch, and the control valve disconnects the output branch connected to the liquid outlet of one battery pack. Another multi-way valve controls the connection between the liquid inlet of another battery pack and the other end of the series branch, and another multi-way valve disconnects the input branch connected to the liquid inlet of another multi-way valve. At this time, the multi-way valve located on the output branch connected to one battery pack can control all the liquid cooling medium flowing out of the liquid outlet of one battery pack to flow to another battery pack through the series branch, so as to replenish the liquid in the other battery pack and improve the heat dissipation efficiency of the other battery pack.

[0014] In some embodiments, the output branch connected to the liquid outlet of a battery pack includes two sub-pipelines, one end of one sub-pipeline is connected to the liquid outlet of a battery pack, the other end of one sub-pipeline is connected to a multi-way valve, one end of another sub-pipeline is connected to the output main line, and the other end of another sub-pipeline is connected to a multi-way valve; the input branch connected to the liquid inlet of another battery pack includes two branch-pipelines, one end of one branch-pipeline is connected to the liquid inlet of another battery pack, the other end of one branch-pipeline is connected to another multi-way valve, one end of another branch-pipeline is connected to the input main line, and the other end of another branch-pipeline is connected to another multi-way valve; one end of the series branch is connected to a multi-way valve, and the other end of the series branch is connected to another multi-way valve.

[0015] In this embodiment, since one input branch and one output branch will be disconnected when the series branches are turned on, one input branch and one output branch will be disconnected among the multiple input branches and multiple output branches. The liquid-cooling medium of the input main line will reduce the diversion of one input branch, thereby increasing the flow rate of the liquid-cooling medium of other input branches, thereby increasing the flow rate of the liquid-cooling medium entering the battery pack, and improving the heat dissipation capacity of the battery pack during thermal runaway.

[0016] In some embodiments, a multi-way valve and another multi-way valve both include a first interface, a second interface, and a third interface; the other end of a sub-pipeline is connected to the first interface of a multi-way valve, and the other end of the other sub-pipeline is connected to the second interface of the one multi-way valve; the other end of a branch pipeline is connected to the first interface of another multi-way valve, and the other end of another branch pipeline is connected to the second interface of another multi-way valve; one end of a series branch is connected to the third interface of a multi-way valve, and the other end of the series branch is connected to the third interface of another multi-way valve.

[0017] In this embodiment, because one end of the series branch is connected to the third port of one multi-way valve, and the other end of the series branch is connected to the third port of another multi-way valve, when the first and third ports of both multi-way valves connected by a series branch are connected, the series branch can be connected while one input branch and one output branch are disconnected.

[0018] In some embodiments, multiple battery packs are stacked, and the two outermost battery packs in the stacking direction of the multiple battery packs are the first battery pack and the second battery pack, respectively. The output branch connected to the first battery pack is provided with a multi-way valve, and the input branch connected to the second battery pack is provided with a multi-way valve. The input branch and the output branch connected to the battery pack located between the first battery pack and the second battery pack in the stacking direction of the multiple battery packs are each provided with a multi-way valve; the number of series branches is multiple, and the multi-way valve on the output branch connected to one battery pack and the multi-way valve on the input branch connected to the other battery pack between any two adjacent battery packs are connected through a series branch.

[0019] Because the two ends of the series branch are connected to two different multi-way valves, the two multi-way valves can control whether the series branch can connect to the output branches and input branches connected to different battery packs. When the series branch connects to the output branches and input branches connected to different battery packs, at least one of the multiple input branches and output branches is disconnected. The liquid cooling medium input to the main trunk will reduce the diversion of at least one input branch, thereby increasing the flow rate of the liquid cooling medium to the other input branches, thereby increasing the flow rate of the liquid cooling medium entering the battery pack and improving the heat dissipation capacity of the battery pack in the event of thermal runaway. For the battery pack connected to the disconnected input branch, such as the first battery pack, the flow rate of the incoming liquid cooling medium can also be increased because it is in a series relationship with the other battery packs. Therefore, in this embodiment, any battery pack can achieve effective improvement in heat dissipation performance. This is used to effectively suppress thermal runaway in any battery pack.

[0020] In some embodiments, the control valve includes multiple valve switches, each of which is provided on multiple output branches. The valve switches on the output branches are used to control the on / off state of the output branches. A valve switch is provided on the series branch, and the valve switches on the series branch are used to control the on / off state of the series branch. In this embodiment, when the valve switch controls the output branch to be disconnected and the series branch is controlled to connect the liquid outlet of one battery pack to the liquid inlet of another battery pack, the liquid coolant flowing out of one battery pack will enter the other battery pack, thereby increasing the flow rate of the liquid coolant flowing into the other battery pack and improving the heat dissipation capacity of the other battery pack.

[0021] In some embodiments, multiple battery packs are stacked, and no valve switch is provided on the input branch. The input branch always connects the input main road to the liquid inlet of the battery pack, so that the flow rate of the liquid-cooling medium flowing into the multiple battery packs is different. For example, the input branch connected to the topmost battery pack in the stacking direction of the multiple battery packs is not connected to the other battery packs through the series branch, while the input branches of the other battery packs are connected to the output branches of the adjacent upper battery packs through the series branch. Therefore, in this embodiment, the valve switch opens the series branch and disconnects the part between the output branch and the output main road, so that the multiple battery packs are connected in series. The liquid cooling medium output by the battery pack can only flow to the next battery pack, and each input branch is connected. Therefore, except for the topmost battery pack in the stacking direction of the multiple battery packs, each other battery pack can be replenished through the input branch and can also be replenished through the previous battery pack. In the stacking direction of the multiple battery packs, the topmost battery pack has the smallest flow rate of liquid cooling medium flowing into it because no other battery packs replenish it. In the stacking direction of the multiple battery packs, the lower the battery pack, the greater the amount of liquid replenished to it by the adjacent upper battery pack, and the stronger the heat dissipation performance. In other words, the heat dissipation performance gradually increases from top to bottom. In the energy storage device of the related art, the multiple battery packs in the lower battery packs generally have lower fire protection and heat dissipation capabilities. The multiple battery packs in the energy storage device of this embodiment can make the heat dissipation performance of the lower battery packs better, so that the lower battery packs have stronger ability to suppress thermal runaway and are less likely to burn or explode.

[0022] In some embodiments, the control valve further includes valve switches provided on a plurality of input branches, and the valve switches on the input branches are used to control the on and off of the input branches.

[0023] In some embodiments, multiple battery packs are stacked. Except for the input branch connected to the top battery pack in the stacking direction, which is not equipped with a valve switch, valve switches are provided on the input branches connected to other battery packs. When thermal runaway occurs in any battery pack, the valve switch on the input branch can be used to control the input branch to be disconnected, the valve switch on the output branch can be used to control the output branch to be disconnected, and the valve switch on the series branch can be used to control the series branch to connect the liquid inlet and liquid outlet of two adjacent battery packs, so that multiple battery packs are arranged in series, so that the liquid-cooling medium input to the main trunk line enters the multiple battery packs in sequence without being diverted, so that the flow rate of the liquid-cooling medium entering the multiple battery packs is effectively improved, and the heat dissipation performance of the multiple battery packs is effectively improved, so that the battery pack with thermal runaway is effectively suppressed.

[0024] In some embodiments, multiple battery packs each include a housing and multiple battery cells. The housing includes a chamber for accommodating a liquid-cooling medium. The multiple battery cells are located within the chamber and immersed in the liquid-cooling medium. The housing is provided with a liquid inlet and a liquid outlet communicating with the chamber. For a battery pack employing immersion heat dissipation, by connecting two battery packs in series via a series branch, the liquid-cooling medium flowing out of the liquid outlet of one battery pack will flow into the other battery pack, thereby replenishing the liquid-cooling medium for the other battery pack. This can increase the flow rate of the liquid-cooling medium entering the other battery pack. Since the liquid-cooling medium can be replenished from one battery pack to another electromagnetic pack, even if the liquid-cooling medium in the other battery pack rapidly evaporates during thermal runaway, the liquid-cooling medium in one battery pack can be promptly replenished, thereby continuously suppressing thermal runaway and heat spread.

[0025] In some embodiments, multiple battery packs each include a shell and multiple battery cells and a liquid cooling plate located within the shell. The multiple battery cells are provided on the liquid cooling plate, and the liquid cooling plate is provided with a liquid inlet and a liquid outlet. Since the liquid cooling medium flows within the cooling plate rather than within the accommodating cavity, the sealing requirements are lower, the structural complexity is more precise, and thus the cost is lower. By connecting two battery packs in series through a series branch, the flow rate of the liquid cooling medium entering the liquid cooling plate can be effectively increased, thereby effectively improving the ability to suppress thermal runaway battery packs. This makes the energy storage device in this embodiment not only low in cost, but also effectively improves the ability to suppress thermal runaway battery packs.

[0026] In a second aspect, an embodiment of the present application provides an energy storage device, comprising a plurality of stacked battery packs, an input main circuit, a plurality of input branches, an output main circuit, and an output branch circuit, wherein the plurality of battery packs each include a liquid inlet and a liquid outlet, the plurality of input branches each communicate with the input main circuit, the plurality of output branches each communicate with the output main circuit, the plurality of input branches each communicate with the liquid inlets of the plurality of battery packs in a one-to-one correspondence, and the plurality of output branches each communicate with the liquid outlets of the plurality of battery packs in a one-to-one correspondence;

[0027] The energy storage device also includes multiple series branches and multiple multi-way valves. Each of the multiple input branches is connected to a multi-way valve. Along the stacking direction of the multiple battery packs, a series branch is connected between the multi-way valves on the input branches connecting any two adjacent battery packs. The multi-way valves on the input branches connecting any two adjacent battery packs are used to control the disconnection of one input branch when the series branches are connected. In this embodiment, each of the multiple input branches is connected to a multi-way valve. Each of the multiple input branches is connected between the multi-way valves on the input branches connecting any two adjacent battery packs. A multi-way valve is used to control the disconnection of one input branch from the liquid inlet of one battery pack and to control the connection of one input branch to another input branch via a series branch. This reduces the diversion of the input main line by one input branch, thereby increasing the flow of liquid cooling medium into the battery pack, thereby improving the heat dissipation performance of certain battery packs and improving the ability of certain battery packs to suppress thermal runaway.

[0028] In some embodiments, the two outermost battery packs in the stacking direction of the multiple battery packs are the first and second battery packs, respectively. The multi-way valves on the input branches connecting the first and second battery packs are both three-way valves, and the multi-way valves on the input branches connecting the battery pack between the first and second battery packs are both four-way valves. One port of the three-way valve is used to connect to a series branch, and two ports of the four-way valve are used to connect to two series branches. In this embodiment, the three-way and four-way valves can be used to connect multiple series branches, multiple input branches, and multiple output branches, effectively suppressing thermal runaway of the battery packs. Furthermore, due to the lower cost of multi-way valves, manufacturing costs can be effectively reduced.

[0029] In a third aspect, an embodiment of the present application provides an energy storage system, comprising a power converter and an energy storage device as described in any one of the first and second aspects above, wherein the power converter is connected to the energy storage device to perform power conversion on the current input to the energy storage device or output from the energy storage device.

[0030] In a fourth aspect, embodiments of the present application provide a method for controlling liquid cooling of a battery pack of an energy storage device. The energy storage device includes multiple battery packs, parallel pipes, series branches, a control valve, and a liquid cooling system. The multiple battery packs are connected to the liquid cooling system in parallel via the parallel pipes. The multiple battery packs are connected to the liquid cooling system in series via the series branches. The control valve is used to control switching between parallel and series connection of the multiple battery packs.

[0031] The liquid cooling control method includes the following steps:

[0032] Detect whether multiple battery packs are in thermal runaway;

[0033] When none of the multiple battery packs are in thermal runaway, the multiple battery packs are connected to the liquid cooling system in parallel via control valves;

[0034] When at least one of the multiple battery packs experiences thermal runaway, the multiple battery packs are connected to the liquid cooling system in a serial arrangement through control valves.

[0035] In a fifth aspect, an embodiment of the present application provides a method for controlling liquid cooling of a battery pack of an energy storage device, wherein the energy storage device includes multiple battery packs, an input main line, multiple input branches, an output main line, output branches, and multiple control valves. The multiple battery packs each include a liquid inlet and a liquid outlet. The multiple input branches are each connected to the input main line, and the multiple output branches are each connected to the output main line. The multiple input branches are connected to the liquid inlets of the multiple battery packs in a one-to-one correspondence, and the multiple output branches are connected to the liquid outlets of the multiple battery packs in a one-to-one correspondence. Each of the multiple input branches is connected to a control valve for controlling the on / off of the input branch.

[0036] The liquid cooling control method includes the following steps:

[0037] Detect whether multiple battery packs are in thermal runaway;

[0038] When multiple battery packs are not in thermal runaway, the control valve controls multiple input branches to enable flow, so that multiple battery packs are arranged in parallel;

[0039] When at least one battery pack among multiple battery packs is in thermal runaway, the control valve connected to the battery pack in thermal runaway controls the battery pack in thermal runaway to be connected to the input main line, and the control valve connected to the battery pack that is not in thermal runaway controls the battery pack that is not in thermal runaway to be disconnected from the input main line. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0041] FIG1 is an application scenario diagram of an energy storage system provided in an embodiment of the present application;

[0042] FIG2 is a schematic structural diagram of an energy storage device provided in an embodiment of the present application;

[0043] FIG3 is a schematic diagram of multiple battery packs in the energy storage device in FIG2 in a normal working state;

[0044] FIG4 is a schematic diagram showing a state in which at least one of the multiple battery packs in the energy storage device in FIG2 is abnormal;

[0045] FIG5 is a schematic diagram showing a state in which at least one of the multiple battery packs in the energy storage device in FIG2 is abnormal;

[0046] FIG6 is a schematic diagram of another energy storage device provided in an embodiment of the present application;

[0047] FIG7A is a schematic diagram of another energy storage device provided in an embodiment of the present application;

[0048] FIG7B is a schematic diagram of another energy storage device provided in an embodiment of the present application;

[0049] FIG8 is a schematic diagram of another energy storage device provided in an embodiment of the present application;

[0050] FIG9 is a flow chart of a liquid cooling control method for a battery pack of an energy storage device provided in an embodiment of the present application;

[0051] FIG10 is a flow chart of another method for controlling liquid cooling of a battery pack of an energy storage device provided in an embodiment of the present application.

[0052] Explanation of the accompanying symbols: X, stacking direction of multiple battery packs; 1000, energy storage system; 1, energy storage device; 2, power converter; 10, liquid cooling system; 21, compressor; 22, condenser; 23, throttle valve; 24, evaporator; 241, refrigerant side inlet; 242, refrigerant side outlet; 243, liquid cooling side inlet; 244, liquid cooling side outlet; 30, parallel pipeline; 31, output main line; 32, input main line; 33, input branch; 331, first input branch; 332, second input branch; 333, branch pipeline; 334, first branch pipeline; 335, second branch pipeline; 34, output branch; 341, first output branch; 342, second output branch; 343, sub-pipeline; 344, first sub-pipeline; 345, second sub-pipeline; 35, series branch; 40. Control valve; 41. Multi-way valve; 411. First interface; 412. Second interface; 413. Third interface; 414. Fourth interface; 42. Valve switch; 50. Battery module; 51. Battery pack; 52. Housing; 521. Accommodation chamber; 522. Liquid inlet; 523. Liquid outlet; 53. Battery cell; 54. Liquid cooling plate. DETAILED DESCRIPTION

[0053] The following first explains some of the terms involved in the embodiments of this application.

[0054] The terms "first", "second", "third", "fourth", etc. in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] In this specification, the terms "perpendicular" and "parallel" are explained.

[0056] Vertical: The vertical defined in this application is not limited to an absolute vertical intersection relationship (angle of 90 degrees). It allows for non-absolute vertical intersection relationships caused by factors such as assembly tolerance, design tolerance, and structural flatness. It allows for errors in a small angle range. For example, the assembly error range of 80 to 100 degrees can be understood as a vertical relationship.

[0057] Parallel: The parallel defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, allowing for situations where the absolute parallelism is not caused by factors such as assembly tolerance, design tolerance, and the influence of structural flatness. These situations will lead to the sliding fitting part and the first door panel not being absolutely parallel, but this application also defines this situation as parallel.

[0058] FIG1 is an application scenario diagram of an energy storage system 1000 provided in an embodiment of the present application, wherein FIG1 shows that the energy storage system 1000 is applied in three scenarios: a power supply side, a power distribution side, and a user side.

[0059] 1 , the application scenario in FIG1 is provided with three energy storage systems 1000 provided in an embodiment of the present application, which are located at a power supply side, a power distribution side, and a user side, respectively.

[0060] The energy storage system 1000 includes an energy storage device 1 and a power converter 2 . The energy storage device 1 is connected to the power converter 2 so that the power converter 2 performs power conversion on the current input to the energy storage device 1 or the current output from the energy storage device 1 .

[0061] In some embodiments, the energy storage system 1000 located on the power supply side provides storage and output management for the electric energy output by the DC source, helping the DC source on the power supply side maintain output stability and optimize the energy structure.

[0062] Specifically, the DC power output by the DC source passes through the power converter 2 and is input into the energy storage device 1 . At this time, the power converter 2 performs DC-DC conversion and transmits the current input by the DC source to the energy storage device 1 .

[0063] The DC source can be a photovoltaic cell, a wind power generation device, a thermal power generation device, etc.

[0064] In some implementations, the energy storage system 1000 located on the distribution side provides intelligent load management for the transmission and distribution side, ensuring safe, stable, efficient, and low-cost operation of the power grid.

[0065] Specifically, the current transmitted from the power supply side is transmitted to the user side through the transmission grid, and when the power is sufficient, the grid converts part of the electric energy through the power converter 2 and inputs it into the energy storage device 1, and when needed, it is output to the user side through the grid. At this time, the power converter 2 is used to convert the AC power transmitted by the grid into DC power, and then transmits the DC power to the energy storage device 1 for storage, and when needed, it converts the DC into AC and outputs it to the user side through the grid.

[0066] In some implementations, the user-side energy storage system 1000 provides users with peak load shaving and valley filling, as well as stable power quality management. This system can be applied in large-scale industrial, commercial, and residential sectors, as well as emerging areas such as communication base station backup power, UPS backup power, island microgrids, and smart solar-storage-charging-inspection charging stations. This system achieves electricity coverage, reduces social electricity costs, improves user-side power security, and maximizes energy utilization for social and economic benefits.

[0067] Specifically, the AC power transmitted from the distribution side is converted from AC to DC by the power converter 2 and then transmitted to the energy storage device 1 for backup. When the electrical equipment at the user end needs to use electric energy, the DC power can be output by the energy storage device 1, and the DC power is converted into AC power by the power converter 2 and transmitted to the user's electrical equipment. It can be understood that the electrical equipment at the user end refers to the electrical equipment that needs to use electric energy.

[0068] FIG2 is a schematic diagram of the structure of an energy storage device 1 provided in an embodiment of the present application. The energy storage device 1 in this embodiment can be used not only in the energy storage system 1000 in the embodiment of FIG1 , but also in other systems or devices that require the use of the energy storage device 1, such as in a data center or a vehicle.

[0069] 2 , the energy storage device 1 includes a liquid cooling system 10 and a battery module 50 . The liquid cooling system 10 is used to cool and dissipate heat for the battery module 50 .

[0070] In some embodiments, the battery module 50 includes a plurality of battery packs 51 , and the liquid cooling system 10 is used to cool and dissipate heat for the plurality of battery packs 51 .

[0071] In some embodiments, multiple battery packs 51 are stacked. Since multiple battery packs 51 are stacked, multiple battery packs 51 can be arranged regularly, which is beneficial for the arrangement of liquid cooling pipes of the liquid cooling system 10 for the multiple battery packs 51.

[0072] It is understandable that in some other embodiments, the multiple battery packs 51 may also be arranged according to other rules or no rules at all.

[0073] In some embodiments, multiple battery packs 51 each include a shell 52 and multiple battery cells 53. The shell 52 includes a accommodating cavity 521. Multiple battery cells 53 are disposed in the accommodating cavity 521. A condensing working fluid is provided in the accommodating cavity 521. Multiple battery cells 53 are at least partially immersed in the condensing working fluid. The heat of the multiple battery cells 53 is taken away by the condensing working fluid to achieve cooling and heat dissipation.

[0074] Specifically, the shell 52 is provided with a liquid inlet 522 and a liquid outlet 523 connected to the accommodating cavity 521. The liquid inlet 522 and the liquid outlet 523 are respectively connected to the liquid cooling system 10, so that the liquid cooling medium circulates in the accommodating cavity 521 and the liquid cooling system 10, thereby taking away the heat of the battery cell 53 in the accommodating cavity 521.

[0075] It should be noted that the condensing medium may be water, ethylene glycol, thermal oil or fluorinated liquid, or other refrigerant media.

[0076] 2 , in some embodiments, the liquid cooling system 10 includes a compressor 21 , a condenser 22 , a throttle valve 23 and an evaporator 24 . The compressor 21 , the condenser 22 , the throttle valve 23 and the evaporator 24 are sequentially connected through pipelines to form a circulatory loop.

[0077] The compressor 21 is a core component for the liquid cooling system 10 to perform its cooling, heating and power functions. The mechanical form of the compressor 21 can be a scroll machine, a screw machine, or a speed turbine machine, which can achieve an efficient compression process. During the compression process, the refrigerant enters the compressor 21 from the low-pressure port of the compressor 21, and the compressed refrigerant flows out at the high-pressure port of the compressor 21. Among them, the refrigerant can include Freon, R12 (difluoromethane), R22 (difluoromethane), R134a (tetrafluoroethane), R407c, R410a, R290 (propane) or R32 (difluoromethane), etc.

[0078] The condenser 22 is used to cool the refrigerant output by the compressor 21. The refrigerant output from the compressor 21 is a gaseous refrigerant. After the gaseous refrigerant is cooled by the condenser 22, it is converted into a liquid refrigerant. During this process, the refrigerant in the condenser 22 can release a large amount of heat.

[0079] The evaporator 24 is used to perform heat exchange between the refrigerant flowing through the evaporator 24 and the liquid cooling medium flowing through the multiple battery packs 51 and the evaporator 24, and the heat of the liquid cooling medium is taken away by the refrigerant, thereby achieving cooling and heat dissipation of the multiple battery packs 51.

[0080] Specifically, the gaseous refrigerant entering the compressor 21 is compressed into a gaseous refrigerant with a higher pressure and temperature, and then flows to the condenser 22. Through the condenser 22, the gaseous refrigerant can exchange heat with the cooling medium and liquefy the gaseous refrigerant into liquid refrigerant. Then, when passing through the throttle valve 23, it can be converted from liquid refrigerant to gaseous refrigerant through the throttle valve 23. When the gaseous refrigerant passes through the evaporator 24, it exchanges heat with the liquid cooling medium passing through the evaporator 24 at the same time to cool and dissipate heat for multiple battery packs 51. Then the gaseous refrigerant flows to the compressor 21 again to form a cycle.

[0081] 2 , in some embodiments, the liquid cooling system 10 further includes parallel pipes 30 for communicating with the liquid inlets 522 and liquid outlets 523 of the multiple battery packs 51. The parallel pipes 30 connect the accommodating chambers 521 of the multiple battery packs 51 to the evaporator 24, allowing the liquid coolant to circulate between the multiple battery packs 51 and the evaporator 24 to dissipate heat from the multiple battery packs 51.

[0082] Specifically, the evaporator 24 includes an inlet 241 and an outlet 242 on the refrigerant side, as well as an inlet 243 and an outlet 244 on the liquid cooling side. The throttle valve 23 is connected to the refrigerant inlet 241, and the condenser 22 is connected to the refrigerant outlet 242. In this way, the refrigerant can circulate through the compressor 21, the condenser 22, the throttle valve 23, and the refrigerant side of the evaporator 24. The inlet 243 and the outlet 244 on the liquid cooling side are used to communicate with the parallel pipeline 30.

[0083] In some embodiments, the parallel pipeline 30 includes an output main line 31, an input main line 32, multiple input branches 33, and multiple output branches 34. The output main line 31 is connected to the outlet 244 on the liquid-cooled side of the evaporator 24, and the input main line 32 is connected to the inlet 243 on the liquid-cooled side of the evaporator 24. The multiple input branches 33 are all connected to the input main line 32, so that the liquid-cooled working medium flowing out of the evaporator 24 can be divided through the input main line 32 and then flow to the multiple input branches 33. The multiple output branches 34 are connected to the output main line 31, so that the liquid-cooled working medium flowing out of the multiple output branches 34 can all flow to the output main line 31 and then flow to the evaporator 24.

[0084] The multiple input branches 33 are used to communicate with the liquid inlets 522 of the multiple battery packs 51. Specifically, the liquid inlet 522 of each battery pack 51 is connected to one input branch 33. The multiple output branches 34 are used to communicate with the liquid outlets 523 of the multiple battery packs 51. Specifically, the liquid outlet 523 of each battery pack 51 is connected to one output branch 34. In other words, the multiple input branches 33 are connected to the liquid inlets 522 of the multiple battery packs 51 in a one-to-one correspondence, and the multiple output branches 34 are connected to the liquid outlets 523 of the multiple battery packs 51 in a one-to-one correspondence. In this embodiment, each of the multiple battery packs 51 can receive the liquid cooling medium flowing through the evaporator 24 through the input branches 33 and the input main line 32 to perform heat exchange with the battery cells 53 in the battery pack 51, thereby cooling the battery cells 53 in the battery pack 51. Each battery pack 51 can then deliver liquid cooling fluid, which has absorbed heat from the battery cells 53, to the evaporator 24 via the output branch 34 and the output main line 31. The fluid then exchanges heat with the refrigerant in the evaporator 24, transferring the heat to the refrigerant. This cycle effectively dissipates heat and cools multiple battery packs 51.

[0085] It will be understood that in this embodiment, when the input trunk line 32, the output trunk line 31, all the input branches 33, and all the output branches 34 are flowing normally, the multiple battery packs 51 are connected to the input trunk line 32 and the output trunk line 31 in parallel. That is, the liquid cooling medium flowing out of the liquid outlet 523 of each battery pack 51 flows directly to the output trunk line 31, rather than to the liquid inlet 522 of other battery packs 51. When the battery packs 51 are operating normally, because the multiple battery packs 51 are connected to the input trunk line 32 and the output trunk line 31 in parallel, the flow resistance of the liquid cooling medium in the input trunk line 32, the output trunk line 31, the input branches 33, and the output branches 34 can be reduced, thereby reducing the power of the drive pump that drives the liquid cooling medium to flow, thereby reducing energy consumption.

[0086] 2 , in some embodiments, the liquid cooling system 10 further includes a series branch 35 and a control valve 40 .

[0087] One end of the series branch 35 is connected to the liquid outlet 523 of one battery pack 51, and the other end of the series branch 35 is connected to the liquid inlet 522 of another battery pack 51. The series branch 35 can flow the liquid-cooling medium flowing out of the liquid outlet 523 of one battery pack 51 to the liquid inlet 522 of another battery pack 51, so that one battery pack 51 and another battery pack 51 are arranged in series.

[0088] Specifically, when the series branch 35 is not flowing, while the input trunk 32, the output trunk 31, all the input branches 33, and all the output branches 34 are flowing normally, then one battery pack 51 and another battery pack 51 are connected in parallel with the input trunk 32 and the output trunk 31. When the series branch 35 is flowing and connects one battery pack 51 and another battery pack 51, while the input trunk 32 and the input branches 33 are disconnected, and the output trunk 31 and the output branches 34 are disconnected, then one battery pack 51 and another battery pack 51 are connected in series with the input trunk 32 and the output trunk 31.

[0089] The control valve 40 is used to control the switching between series connection and parallel connection of the one battery pack 51 and the other battery pack 51. Specifically, when the multiple battery packs 51 are operating normally, the control valve 40 can be used to control the connection of one battery pack 51 and the other battery pack 51 to the input main line 32 and the output main line 31 in parallel. In this case, the flow resistance can be effectively reduced, and the energy consumption can be effectively reduced. When thermal runaway occurs in at least one of the multiple battery packs 51, the control valve 40 can be used to control the connection of the one battery pack 51 and the other battery pack 51 to the input main line 32 and the output main line 31 in series. In this case, the flow rate of the liquid cooling medium flowing into the battery pack 51 in thermal runaway can be effectively increased. The specific reason for the increase in the flow rate of the liquid-cooling medium flowing into the battery pack 51 with thermal runaway is that one battery pack 51 and another battery pack 51 are connected to the input main road 32 and the output main road 31 in series, so that the input branch 33 between the liquid inlet 522 of the other battery pack 51 and the input main road 32 is disconnected, so that the input branch 33 connected to the battery pack 51 no longer diverts the input main road 32, and the flow rate of the input main road 32 to other input branches 33 becomes larger, and the flow rate of the liquid-cooling medium flowing to other battery packs 51 is increased. At this time, the heat dissipation performance of each battery pack 51 is improved, so as to effectively suppress the battery pack 51 with thermal runaway.

[0090] In some embodiments, when thermal runaway occurs in another battery pack 51, the control valve 40 is configured to disconnect the output branch 34 connected to the liquid outlet 523 of the one battery pack 51 from the output main line 31 while controlling the series branch 35 to connect the liquid outlet 523 of the one battery pack 51 with the liquid inlet 522 of the other battery pack 51. In this embodiment, when thermal runaway occurs in another battery pack 51, the control valve 40 controls the liquid outlet 523 of the one battery pack 51 to connect with the liquid inlet 522 of the other battery pack 51 in series via the series branch 35. This allows the liquid cooling medium flowing out of the liquid outlet 523 of the one battery pack 51 to enter the other battery pack 51. Simultaneously, the liquid cooling medium can also be input into the other battery pack 51 via the input branch 33 connected to the other battery pack 51, thereby increasing the flow rate of the liquid cooling medium input into the other battery pack 51 and effectively suppressing the thermal runaway battery pack 51.

[0091] In some embodiments, when thermal runaway occurs in at least one of the battery packs 51, the control valve 40 is used to control the series branch 35 to connect the liquid outlet 523 of the one battery pack 51 and the liquid inlet 522 of the other battery pack 51, so that the one output branch 34 connected to the liquid outlet 523 of the one battery pack 51 is disconnected from the output main road 31, and the other input branch 33 connected to the liquid inlet 522 of the other battery pack 51 is disconnected from the input main road 32. In this embodiment, since the control valve 40 controls the series branch 35 to connect the liquid outlet 523 of the one battery pack 51 and the liquid inlet 522 of the other battery pack 51, the one output branch 34 connected to the liquid outlet 523 of the one battery pack 51 is disconnected from the output main road 31, and the other input branch 33 connected to the liquid inlet 522 of the other battery pack 51 is disconnected from the input main road 32, so that one battery pack 51 and the other battery pack 51 are arranged in series, so that the input branch 33 connected to the other battery pack 51 no longer diverts the input main road 32, and the flow rate of the input main road 32 to the other input branches 33 becomes larger, and the flow rate of the liquid cooling medium to the other battery packs 51 is increased. At this time, the heat dissipation performance of each battery pack 51 is improved, so as to effectively suppress the battery pack 51 from thermal runaway.

[0092] It should be noted that the thermal runaway of the battery pack 51 mentioned above and below means that the voltage value of the battery pack 51 is lower than the thermal runaway voltage value, or the air pressure value inside the battery pack 51 is greater than the thermal runaway air pressure value, or the temperature of the battery pack 51 is higher than the thermal runaway temperature value, or combustible gas exceeding a certain value is detected inside the battery pack 51.

[0093] In some other embodiments, when the control valve 40 is used to control the series branch 35 to connect the liquid outlet 523 of one battery pack 51 and the liquid inlet 522 of another battery pack 51, and disconnect the output branch 34 between the liquid outlet 523 of one battery pack 51 and the output main road 31, the input branch 33 between the liquid inlet 522 of another battery and the input main road 32 is in a connected state. In this embodiment, the other battery pack 51 can not only receive the liquid-cooling medium of the battery pack 51 whose output branch 34 between the liquid outlet 523 and the output main road 31 is disconnected, but the other battery pack 51 can also obtain the liquid-cooling medium flowing into the input branch 33, thereby increasing the flow rate of the other battery pack 51 and improving the heat dissipation performance of the other battery pack 51.

[0094] 2 , in some embodiments, one end of a series branch 35 is connected to an input branch 33 connected to one battery pack 51, and the other end of the series branch 35 is connected to an output branch 34 connected to another battery pack 51. In other words, a series branch 35 connects an input branch 33 and an output branch 34 belonging to different battery packs 51.

[0095] The number of battery packs 51 is n, the number of input branches 33 is n, the number of output branches 34 is n, and the number of series branches 35 is n-1. The n-1 input branches 33 and the n-1 output branches 34 are connected via n-1 series branches 35. One of the multiple input branches 33 is not connected to other output branches 34 via the series branch 35, and one of the multiple output branches 34 is not connected to other input branches 33 via the series branch 35. For ease of description, the input branch 33 not connected to other output branches 34 via the series branch 35 is referred to as the first input branch 331, and the input branch 33 connected to other output branches 34 via the series branch 35 is referred to as the second input branch 332. The output branch 34 not connected to the gas input branch 33 through the series branch 35 is set as the first output branch 341 , and the output branch 34 connected to other input branches 33 through the series branch 35 is set as the second output branch 342 .

[0096] The n output branches 34 include one first output branch 341 and n-1 second output branches 342. The n input branches 33 include one first input branch 331 and n-1 second input branches 332. A series branch 35 is connected between a second output branch 342 and a second input branch 332, and neither the second output branch 342 nor the second input branch 332 connected to the series branch 35 is connected to any other series branch 35.

[0097] It can be understood that the number n in this embodiment is consistent with the number of multiple battery packs 51, wherein n can be any natural number greater than 1, such as 2, 3, 4, 5 or other numbers.

[0098] It is understandable that the control valve 40 can independently control whether the liquid cooling medium flows through each series branch 35 .

[0099] 2 , in some embodiments, the control valve 40 includes multiple multi-way valves 41. Multiple second output branches 342 and multiple second input branches 332 are each provided with a multi-way valve 41. One end of the series branch 35 is connected to the multi-way valve 41 on one second input branch 332, and the other end of the series branch 35 is connected to the multi-way valve 41 on one second output branch 342. In this embodiment, the multi-way valve 41 on the second output branch 342 can control the liquid cooling medium flowing out of the liquid outlet 523 of the battery pack 51 to flow entirely through the second output branch 342 to the output main trunk 31, or control the liquid cooling medium flowing out of the liquid outlet 523 of the battery pack 51 to flow entirely through the series branch 35 to another battery pack 51, thereby replenishing the liquid in the other battery pack 51 and improving the heat dissipation efficiency of the other battery pack 51.

[0100] Specifically, when multiple battery packs 51 are operating normally, the multi-way valve 41 located on the second output branch 342 can control all the liquid-cooling working fluids flowing out of the liquid outlet 523 of the battery pack 51 to flow to the output main line 31 through the second output branch 342. The multi-way valve 41 located on the second input branch 332 can control all the liquid-cooling working fluids flowing out of the output main line 31 to flow to the battery pack 51 through the second output branch 342. When a battery pack 51 suffers from thermal runaway, the control valve 40 can be used to control all the liquid-cooling working fluids flowing out of the liquid outlet 523 of another battery pack 51 that has not run away to flow to the battery pack 51 with thermal runaway through the series branch 35, so as to replenish the battery pack 51 with thermal runaway. The control valve 40 can also control the liquid cooling medium flowing out of the liquid outlets 523 of all other battery packs 51 to flow directly or indirectly to the battery pack 51 with thermal runaway through the series branch 35, so as to maximize the heat dissipation performance of the battery pack 51 with thermal runaway.

[0101] 2 , in some embodiments, the plurality of multi-way valves 41 are all three-way valves, and the plurality of multi-way valves 41 include a first port 411 , a second port 412 , and a third port 413 .

[0102] In some embodiments, each of the multiple second output branches 342 includes two sub-pipelines 343. For ease of description, one of the sub-pipelines 343 is referred to as the first sub-pipeline 344, and the other sub-pipeline 343 is referred to as the second sub-pipeline 345. One end of the first sub-pipeline 344 is connected to the liquid outlet 523 of the battery pack 51, and the other end of the first sub-pipeline 344 is connected to the first port 411 of the multi-way valve 41. One end of the second sub-pipeline 345 is connected to the output main line 31, and the other end of the second sub-pipeline 345 is connected to the second port 412 of the multi-way valve 41.

[0103] In some embodiments, each of the multiple second input branches 332 includes two branch lines 333. For ease of description, one of the branch lines 333 is referred to as the first branch line 334, and the other branch line 333 is referred to as the second branch line 335. One end of the first branch line 334 is connected to the liquid outlet 523 of the battery pack 51, and the other end of the first branch line 334 is connected to the first port 411 of the multi-way valve 41. One end of the second branch line 335 is connected to the input main line 32, and the other end of the second branch line 335 is connected to the second port 412 of the multi-way valve 41.

[0104] In some embodiments, one end of the series branch 35 is communicated with the third port 413 of one multi-way valve 41 , and the other end of the series branch 35 is communicated with the third port 413 of another multi-way valve 41 .

[0105] In this embodiment, since multi-way valves 41 are provided on multiple second output branches 342 and multiple second input branches 332, each second output branch 342 and each second input branch 332 can be controlled by the multi-way valve 41. Since the two ends of the series branch 35 are respectively connected to two different multi-way valves 41, the two multi-way valves 41 can control whether the series branch 35 can connect to the second output branch 342 and the second input branch 332. When the first and third ports 411, 413 of the two multi-way valves 41 connected to a series branch 35 are both connected, at least one of the multiple input branches 33 and the multiple output branches 34 is disconnected. The liquid cooling medium input to the main trunk 32 is diverted to at least one input branch 33, thereby increasing the flow of the liquid cooling medium to the other input branches 33 and thereby increasing the flow of the liquid cooling medium into the battery pack 51. For the battery pack 51 connected to the disconnected input branch 33, since it is in a series relationship with the other battery packs 51, the flow of the liquid cooling medium is also increased. This effectively improves the heat dissipation performance of any battery pack 51, thereby effectively suppressing thermal runaway in any battery pack 51.

[0106] It can be understood that, when more series branches 35 connect two multi-way valves 41 with the first interface 411 and the third interface 413 being connected, more input branches 33 and output branches 34 are disconnected, and the flow rate of liquid cooling medium flowing into multiple battery packs 51 is greater, and the heat dissipation performance of the battery pack 51 is improved.

[0107] For ease of description, two battery packs 51 among the multiple battery packs 51 are used as an example, with one of the two battery packs 51 being designated as the first battery pack 51 and the other as the second battery pack 51. The first battery pack 51 is connected to the second output branch 342, and the second battery pack 51 is connected to the second input branch 332. The liquid-cooling medium flowing out of the outlet 244 on the liquid-cooling side of the evaporator 24 flows through the output main line 31 and the input branch 33 to the liquid inlet 522 of the first battery pack 51, enters the accommodating cavity 521 of the first battery pack 51, and then flows through the liquid outlet 523 of the first battery pack 51 to the first sub-pipeline 344 of the second output branch 342.

[0108] When the two battery packs 51 are in a normal state, the first interface 411 and the second interface 412 of the multi-way valve 41 on the second output branch 342 are connected, and the first sub-pipeline 344 and the second sub-pipeline 345 are connected through the multi-way valve 41. At this time, all the liquid cooling medium flows through the first sub-pipeline 344 to the second sub-pipeline 345, and then flows to the output main line 31. At this time, the second input branch 332 and the output branch 34 of the second battery pack 51 also flow normally, and the first battery pack 51 cannot replenish the second battery pack 51.

[0109] When one of the two battery packs 51 is in a thermal runaway state, for example, the second battery pack 51 is in a thermal runaway state, the first interface 411 and the third interface 413 of the multi-way valve 41 on the second output branch 342 of the first battery pack 51 are connected, and the first interface 411 and the third interface 413 of the multi-way valve 41 on the second input branch 332 of the second battery pack 51 are connected. At this time, all the liquid cooling medium flows to the series branch 35 through the first sub-pipeline 344, and then flows to the second battery pack 51 through the first branch pipe 334, so that the second battery pack 51 can be replenished with liquid to improve the heat dissipation performance of the second battery pack 51. It can be understood that, since the first battery pack 51 and the second battery pack 51 are in a series relationship at this time, the diversion of the liquid-cooling medium flowing in the input main line 32 is reduced, and the flow rate of the liquid-cooling medium flowing from the input main line 32 to the input branch line 33 connected to the first battery pack 51 will increase, thereby increasing the amount of liquid-cooling medium flowing into the accommodating cavity 521 of the first battery pack 51. At this time, the heat dissipation performance of the first battery pack 51 can also be improved at the same time.

[0110] Figure 3 is a schematic diagram of multiple battery packs 51 in the energy storage device 1 in Figure 2 in a normal working state.

[0111] Referring to Figure 3 , when multiple battery packs 51 are operating normally, the three-way valves located on the multiple second input branches 332 and the three-way valves located on the multiple second output branches 342 are both connected to the first interface 411 and the second interface 412. At this time, all second input branches 332 and second output branches 342 are open, and liquid cooling medium is not allowed to flow through all series branches 35. The liquid cooling medium flowing out of the outlet 244 on the liquid cooling side of the evaporator 24 flows through the input main line 32 to the multiple input branches 33. At this time, the multiple input branches 33 include both the first input branch 331 and the second input branch 332. The multiple inlet and outlet branches divert the liquid cooling medium in the input main line 32 to flow to the liquid inlet 522 of the multiple battery packs 51, and then enter the multiple battery packs 51. The liquid cooling medium that enters the cavities 521 of the battery packs 51 through the liquid inlets 522 of the battery packs 51 can soak the battery cells 53 in the battery packs 51, thereby cooling the battery packs 51 in normal operation. The liquid cooling medium in the cavities 521 of the battery packs 51 then flows through the liquid outlets 523 of the battery packs 51 to the output branches 34. The output branches 34 at this time include both the first output branch 341 and the second output branch 342. The liquid cooling medium then flows back to the main output path 31 through the output main path 31, and is then transported to the inlet 243 on the liquid-cooled side of the evaporator 24, thus forming a cycle. During the cycle, the liquid cooling medium dissipates heat from the battery packs 51, thereby achieving a cooling effect.

[0112] Since, under normal working conditions, multiple input branches 33 divert the input main line 32, the flow rate of the liquid cooling medium from each output branch 34 to the multiple battery packs 51 is small, and the flow resistance is small, which can reduce the overall power consumption of the liquid cooling system 10, thereby reducing the power consumption of the energy storage device 1 and reducing the cost of use.

[0113] It can be understood that at this time, the multiple battery packs 51 are in a parallel relationship, and the liquid inlet 522 and the liquid outlet 523 of each battery pack 51 are directly connected to the inlet 243 and the outlet 244 on the liquid-cooled side of the evaporator 24. At this time, the liquid-cooled working medium flowing out of the outlet 244 on the liquid-cooled side of the evaporator 24 can be diverted to reduce the flow resistance flowing through each battery pack 51.

[0114] FIG4 is a schematic diagram illustrating a situation in which at least one of the multiple battery packs 51 in the energy storage device 1 in FIG2 is in an abnormal state (e.g., thermal runaway, combustion, etc.). In FIG4 , all of the multiple battery packs 51 are connected in series. The dashed lines in FIG4 represent lines that can flow, while the dashed lines represent lines that cannot flow.

[0115] 4 , when at least one of the multiple battery packs 51 is in an abnormal state, the three-way valves located on the multiple second output branches 342 and the multiple second input branches 332 are connected to the first interface 411 and the third interface 413. At this time, all the first sub-pipelines 344 are not connected to the second sub-pipelines 345, but all the first sub-pipelines 344 are connected to one end of the series branch 35. Similarly, all the second branch-pipelines 335 are not connected to the second branch-pipelines 335, but all the first branch-pipelines 334 are connected to the other end of the series branch 35, so that the multiple battery packs 51 are connected in series by the multiple first sub-pipelines 344, the multiple series branches 35 and the multiple first branch-pipelines 334. At this time, the liquid-cooling medium flowing out of the outlet 244 on the liquid-cooling side of the evaporator 24 flows to the first input branch 331 through the input main line 32, and then flows to the battery pack 51 provided with the first input branch 331 through the first input branch 331. The liquid-cooling medium flowing into the battery pack 51 flows to other battery packs 51 in turn through multiple first sub-pipelines 344, multiple series branches 35 and multiple first branch lines 334, and finally flows out of the last battery pack 51 flowing through from the first output branch 341, flows back to the output main line 31, and then flows back to the inlet 243 on the liquid-cooling side of the evaporator 24, thus forming a cycle.

[0116] Because the second branch pipes 335 of the multiple second input branches 332 and the second sub-pipes 345 of the multiple second output branches 342 are closed, the liquid cooling medium input to the main trunk 32 is not diverted by the other input branches 33 and flows entirely through the first input branch 331 to the battery pack 51. This significantly increases the flow rate and flow velocity into the battery pack 51 compared to when the battery pack 51 is in normal operation. This increases the flow rate of liquid cooling medium entering the accommodating cavity 521 of the battery pack 51 per unit time, thereby improving the heat exchange efficiency with the battery pack 51 and, consequently, the heat dissipation capacity of the battery pack 51. Because the multiple battery packs 51 are connected in series, the liquid cooling medium flowing into each battery pack 51 is the entirety of the liquid cooling medium output from the input main trunk 32. This effectively increases the flow rate of liquid cooling medium entering the accommodating cavity 521 of the battery pack 51 per unit time for each battery pack 51, thereby improving the heat dissipation performance of each battery pack 51. Therefore, when one or more of the multiple battery packs 51 have an abnormality, such as thermal runaway, each battery pack 51 experiencing thermal runaway can be effectively cooled, so that the battery pack 51 experiencing thermal runaway can be suppressed and prevented from becoming further out of control, such as burning.

[0117] FIG5 is a schematic diagram illustrating a situation in which at least one of the multiple battery packs 51 in the energy storage device 1 in FIG2 is in an abnormal state (e.g., thermal runaway, combustion, etc.). In FIG5 , some of the multiple battery packs 51 are connected in series. The dashed lines in FIG5 represent battery flow, while the dotted lines represent battery non-flow.

[0118] 5 , when at least one of the multiple battery packs 51 is in an abnormal state, such as thermal runaway, and the battery pack 51 in thermal runaway is simultaneously connected to the second input branch 332 and the second output branch 342, the first port 411 and the third port 413 of the three-way valve on at least one of the second input branch 332 and the second output branch 342 that are simultaneously connected to the battery pack 51 in thermal runaway are connected, so that the battery pack 51 in thermal runaway is connected in series with the other battery packs 51 through the series branch 35, thereby making at least one of the second input branch 332 and the second output branch 342 in the battery pack 51 in thermal runaway be connected. Branch 332 is not connected to the input main road 32, and at least one second output branch 342 is not connected to the output main road 31. Because at least one second input branch 332 is reduced and is not diverted from the input main road 32, the flow of the liquid-cooling medium flowing from the input main road 32 to other input branches 33 will increase, and then the flow of the liquid-cooling medium flowing to each battery pack 51 will increase, so as to improve the heat dissipation performance, thereby suppressing the thermal runaway battery pack 51 and preventing the thermal runaway battery pack 51 from becoming further out of control, such as combustion.

[0119] In addition, since the battery pack 51 with thermal runaway is connected in series with other battery packs 51, especially when the second output branch 342 of the other battery pack 51 is connected to the second input branch 332 of the battery pack with thermal runaway 51 through the series branch 35, when the series branch 35 is connected, the liquid-cooling medium in the other battery pack 51 can flow out through the first sub-pipeline 344 and then flow to the battery pack with thermal runaway 51 through the series branch 35 and the first branch pipe 334, so that the liquid-cooling medium flowing out of the other battery packs 51 can be directly obtained, so that more liquid-cooling medium can participate in the circulation, thereby improving the heat dissipation effect. Even if the liquid-cooling medium in another battery pack 51 evaporates quickly during thermal runaway, it can be replenished in time through the liquid-cooling medium in one battery pack 51, thereby continuously suppressing thermal runaway and heat spread.

[0120] It can be understood that any at least two battery packs 51 among the multiple battery packs 51 are connected in series through the series branch 35, which can reduce the diversion of the input main line 32, effectively increase the flow rate of the liquid cooling medium when entering each battery pack 51, and improve the heat dissipation effect of all battery packs 51.

[0121] 2-5, the energy storage device 1 in this embodiment, when the battery pack 51 is in a normal working medium state as shown in FIG3, can effectively reduce the flow resistance of the liquid cooling medium during circulation by diverting multiple input branches 33 and output branches 34, thereby effectively reducing the power consumption of the energy storage device 1 and reducing the cost of use. When the battery pack 51 as shown in FIG4 or FIG5 is in an abnormal state, the flow rate of the liquid cooling medium entering the abnormal battery pack 51 can be increased by setting all the battery packs 51 in series (as shown in FIG4) or part of the battery packs 51 in series (as shown in FIG5), thereby improving the heat dissipation capacity of the abnormal battery pack 51. Moreover, by switching the multiple battery packs 51 in series or in parallel by the multi-way valve 41, not only is the pipeline layout simplified, but the cost of the multi-way valve 41 is also lower than that of the solenoid valve.

[0122] FIG6 is a schematic diagram of another energy storage device 1 provided in an embodiment of the present application; the main difference between the energy storage device 1 in FIG6 and the embodiment of FIG2 is that the liquid cooling method of the battery pack 51 is different.

[0123] Referring to FIG6 , the energy storage device 1 includes multiple battery packs 51 . Each of the multiple battery packs 51 includes a housing 52 and multiple battery cells 53 and a liquid cooling plate 54 located within the housing 52 . The multiple battery cells 53 are disposed on the liquid cooling plate 54 , and the liquid cooling plate 54 is provided with a liquid inlet 522 and a liquid outlet 523 . In this embodiment, the liquid cooling medium flows in the liquid cooling plate 54 , and then heat is exchanged with the multiple battery cells 53 through the liquid cooling plate 54 to dissipate heat from the multiple battery cells 53 in the battery pack 51 . In addition, since the liquid cooling medium flows within the cooling plate 54 rather than within the accommodating chamber 521 , the sealing requirements are lower, the structural complexity is more precise, and thus the cost is lower. Compared to the energy storage device 1 in the embodiment of FIG2 , the heat dissipation of the energy storage device 1 in the embodiment of FIG6 is relatively poorer, especially when the battery pack 51 experiences thermal runaway, and the heat cannot be effectively dissipated. However, due to the provision of the series branch 35, when a battery pack 51 experiences an abnormality, multiple battery packs 51 can be connected in series, as in the embodiments of FIG. 4 or FIG. 5 (see the embodiments of FIG. 4 and FIG. 5 for the specific principles), thereby effectively increasing the flow of the liquid cooling medium entering the liquid cooling plate 54 and thus effectively improving the ability to suppress thermal runaway of the battery pack 51. As a result, the energy storage device 1 of the embodiment of FIG. 6 is not only low-cost, but also effectively improves the ability to suppress thermal runaway of the battery pack 51.

[0124] It should be noted that the liquid cooling medium, series branch 35, battery pack 51, battery cell 53, liquid inlet 522 and liquid outlet 523 mentioned in the embodiment of Figure 6 are all referred to the previous embodiment and will not be repeated here.

[0125] FIG7A is a schematic diagram of another energy storage device 1 provided in an embodiment of the present application; FIG7B is a schematic diagram of another energy storage device 1 provided in an embodiment of the present application. The difference between FIG7B and FIG7A is that valve switches 42 are also provided on the multiple input branches 33 in FIG7B.

[0126] 7A-7B , the energy storage device 1 includes a liquid cooling system 10 and multiple battery packs 51. The liquid cooling system 10 includes an input trunk line 32, an output trunk line 31, multiple input branches 33, and multiple output branches 34. Each of the multiple battery packs 51 has multiple liquid inlets 522 and multiple liquid outlets 523. The liquid cooling system 10, the multiple battery packs 51, the input trunk line 32, the output trunk line 31, the multiple input branches 33, the multiple output branches 34, the multiple liquid inlets 522, and the multiple liquid outlets 523 can all be described with reference to the previous embodiments, and will not be further described here.

[0127] In some embodiments, in the stacking direction X of multiple battery packs 51, a series branch 35 is connected between any two adjacent battery packs 51, one end of the series branch 35 is connected to the output branch 34 of one battery pack 51, and the other end of the series branch 35 is connected to the input branch 33 of another battery pack 51.

[0128] The control valve 40 includes multiple valve switches 42, which can be solenoid valves or other valves capable of controlling the on / off state of a pipeline. Each series branch 35 is provided with a valve switch 42, and each output branch 34 is provided with a valve switch 42. Thus, the series branches 35 can be opened and closed by the valve switches 42 on the series branches 35, and the output branches 34 can be opened and closed by the valve switches 42 on the output branches 34. When the valve switches 42 control the output branches 34 to be closed, and the series branches 35 are controlled to connect the liquid outlet 523 of one battery pack 51 with the liquid inlet 522 of another battery pack 51, the liquid coolant flowing out of one battery pack 51 enters the other battery pack 51, thereby increasing the flow rate of the liquid coolant in the other battery pack 51 and improving the heat dissipation capacity of the other battery pack 51.

[0129] 7A , in some embodiments, the input branch 33 is not provided with a valve switch 42, and the input branch 33 always connects the input main road 32 with the liquid inlet 522 of the battery pack 51, so that the flow rate of the liquid-cooling medium flowing into the multiple battery packs 51 is different. For example, the input branch 33 connected to the topmost battery pack 51 in the stacking direction X of the multiple battery packs 51 is not connected to the other battery packs 51 through the series branch 35, while the input branches 33 of the other battery packs 51 are all connected to the output branches 34 of the adjacent upper battery pack 51 through the series branch 35. Therefore, in this embodiment, the valve switch 42 opens the series branch 35 and disconnects the part between the output branch 34 and the output main road 31, so that the multiple battery packs 51 In series connection, the liquid cooling medium output by the front battery pack 51 can only flow to the next battery pack 51, and each input branch 33 is connected, so except for the top battery pack 51 in the stacking direction X of the multiple battery packs 51, each other battery pack 51 can be replenished through the input branch 33, and can also be replenished through the previous battery pack 51. In the stacking direction X of the multiple battery packs 51, the top battery pack 51 has the smallest flow rate of liquid cooling medium flowing into the top battery pack 51 because there is no other battery pack 51 to replenish liquid. In the stacking direction X of the multiple battery packs 51, the lower the battery pack 51 is, the greater the amount of liquid replenished by the adjacent upper battery pack 51, and the stronger the heat dissipation performance. In other words, from top to bottom, the heat dissipation performance gradually increases. In the related art, among the multiple battery packs 51 in the energy storage device 1, the fire-fighting and heat-dissipating capabilities of the battery packs 51 located at the bottom are generally lower. However, the multiple battery packs 51 in the energy storage device 1 of this embodiment can make the heat-dissipating performance of the battery packs 51 located at the bottom better, so that the battery packs 51 located at the bottom have stronger ability to suppress thermal runaway and are less likely to burn or explode.

[0130] 7B , in some embodiments, except for the input branch 33 connected to the topmost battery pack 51 in the stacking direction X of the multiple battery packs 51, which is not provided with a valve switch 42, the input branches 33 connected to the other battery packs 51 are all provided with valve switches 42. When thermal runaway occurs in any battery pack 51, the valve switch 42 on the input branch 33 can be used to control the input branch 33 to be disconnected, the valve switch 42 on the output branch 34 can be used to control the output branch 34 to be disconnected, and the valve switch 42 on the series branch 35 can be used to control the series branch 35 to connect the liquid inlet 522 and the liquid outlet 523 of two adjacent battery packs 51. This allows the multiple battery packs 51 to be arranged in series, so that the liquid-cooling medium input to the main trunk 32 enters the multiple battery packs 51 in sequence without being diverted, so that the flow rate of the liquid-cooling medium entering the multiple battery packs 51 is effectively improved, and the heat dissipation performance of the multiple battery packs 51 is effectively improved, so that the battery pack 51 with thermal runaway is effectively suppressed.

[0131] Fig. 8 is a schematic diagram of another energy storage device 1 provided in an embodiment of the present application. The connection relationship of the series branches 35 in the embodiment of Fig. 8 is different from that in the previous embodiment.

[0132] 8 , the energy storage device 1 includes a liquid cooling system 10 and multiple battery packs 51. The liquid cooling system 10 includes an input trunk line 32, an output trunk line 31, multiple input branches 33, and multiple output branches 34. Each of the multiple battery packs 51 has multiple liquid inlets 522 and multiple liquid outlets 523. The liquid cooling system 10, multiple battery packs 51, the input trunk line 32, the output trunk line 31, the multiple input branches 33, the multiple output branches 34, the multiple liquid inlets 522, and the multiple liquid outlets 523 can all be described with reference to the previous embodiments, and will not be further described here.

[0133] The liquid cooling system 10 also includes a series branch 35 and a multi-way valve 41. A multi-way valve 41 is provided on each input branch 33. Each input branch 33 includes a first pipeline and a second pipeline. One end of the first pipeline is connected to the liquid inlet 522 of the battery pack 51, and the other end of the first pipeline is connected to the multi-way valve 41. One end of the second pipeline is connected to the input main line 32, and the other end of the second pipeline is connected to the multi-way valve 41. The two ends of the series branch 35 are respectively connected to the multi-way valves 41 on the two input branches 33.

[0134] When the multi-way valve 41 connects the first pipeline and the second pipeline, the liquid cooling medium input into the main pipeline 32 can flow to the battery pack 51 through the second pipeline and the first pipeline.

[0135] When the multi-way valve 41 connects the second pipeline and one end of the series branch 35, and the other multi-way valve 41 connects the other end of the series branch 35 with the other first pipeline, the liquid-cooling medium in the input main pipeline 32 can flow into the other battery pack 51 through the second pipeline corresponding to one of the battery packs 51, the series branch 35, and the first pipeline connected to the other battery pack 51. At this time, the liquid-cooling medium no longer flows into at least one of the battery packs 51, which can reduce the diversion of the input main pipeline and increase the flow of the liquid-cooling medium entering the battery pack 51, thereby improving the heat dissipation effect.

[0136] When the multi-way valve 41 connects the second pipeline with one end of the series branch 35, and the other multi-way valve 41 connects the other end of the series branch 35 with the other second pipeline, the liquid cooling medium will no longer flow into at least two battery packs 51, which can reduce the diversion of the input main pipeline and increase the flow of the liquid cooling medium entering the battery pack 51, thereby improving the heat dissipation effect.

[0137] The energy storage device 1 in this embodiment can control which battery packs 51 can enter the liquid cooling medium and which battery packs 51 cannot enter the liquid cooling medium through the multi-way valve 41, thereby adjusting the flow of the liquid cooling medium entering the battery pack 51, thereby improving the heat dissipation effect and suppressing the battery pack 51 from thermal runaway.

[0138] In some embodiments, among the multiple multi-way valves 41, two multi-way valves 41 are three-way valves, each including a first port 411, a second port 412, and a third port 413. The remaining multi-way valves 41 are four-way valves, each including a first port 411, a second port 412, a third port 413, and a fourth port 414. The first port 411 and the second port 412 are used to communicate with the first pipeline or the second pipeline, and the third port 413 and the fourth port 414 are used to communicate with both ends of the series branch 35.

[0139] Figure 9 is a flow chart of a method for controlling liquid cooling of a battery pack 51 of an energy storage device 1 according to an embodiment of the present application. The energy storage device 1 in the embodiment of Figure 9 may be the energy storage device 1 in the embodiments of Figures 2 to 7B in the above embodiments.

[0140] 9 , the energy storage device 1 includes a plurality of battery packs 51, parallel pipes 30, series branches 35, a control valve 40, and a liquid cooling system 10. The plurality of battery packs 51 are connected to the liquid cooling system 10 in parallel via the parallel pipes 30, and the plurality of battery packs 51 are connected to the liquid cooling system 10 in series via the series branches 35. The control valve 40 is used to control the switching between parallel and series connection of the plurality of battery packs 51.

[0141] The liquid cooling control method of the battery pack 51 of the energy storage device 1 includes the following steps:

[0142] S11, detecting whether multiple battery packs 51 are in thermal runaway;

[0143] S121: When none of the multiple battery packs 51 are in thermal runaway, the multiple battery packs 51 are connected to the liquid cooling system 10 in parallel via the control valve 40.

[0144] S122 . When at least one battery pack 51 among the multiple battery packs 51 is in thermal runaway, the multiple battery packs 51 are controlled by the control valve 40 to be connected to the liquid cooling system 10 in a serial arrangement.

[0145] In this embodiment, the multiple battery packs 51 are first detected to determine whether they are in thermal runaway. When the battery packs 51 are operating normally, the control valve 40 can be used to control the multiple battery packs 51 to be connected in parallel to the liquid cooling system 10, thereby reducing the power of the drive pump that drives the flow of the liquid cooling medium to reduce energy consumption. In the event of thermal runaway of the battery pack 51, the control valve 40 is used to control the multiple battery packs 51 to be connected in series to the liquid cooling system 10. Due to the reduced diversion of the liquid cooling medium input to the main trunk line 32, the flow rate of the liquid cooling medium to each battery pack 51 is increased. At this time, the heat dissipation performance of each battery pack 51 is improved, effectively suppressing the battery pack 51 in thermal runaway. The specific reasons why connecting multiple battery packs 51 in parallel can reduce energy consumption and connecting multiple battery packs 51 in series can increase the flow rate of the liquid cooling medium can be referred to the previous embodiment and will not be repeated here.

[0146] Among them, the battery pack 51, the parallel pipeline 30, the series branch 35, the control valve 40, the liquid cooling system 10, the input main line 32, etc. can all refer to the previous embodiments and will not be repeated here.

[0147] Figure 10 is a flow chart of another method for controlling liquid cooling of a battery pack 51 of an energy storage device 1 according to an embodiment of the present application. The energy storage device 1 in the embodiment of Figure 10 may be the energy storage device 1 in the embodiment of Figure 8 in the previous embodiment.

[0148] 10 , the energy storage device 1 includes multiple battery packs 51, an input main line 32, multiple input branches 33, an output main line 31, an output branch 34, and multiple control valves 40. Each of the multiple battery packs 51 includes a liquid inlet 522 and a liquid outlet 523. Each of the multiple input branches 33 is in communication with the input main line 32, and each of the multiple output branches 34 is in communication with the output main line 31. Each of the multiple input branches 33 is in communication with the liquid inlets 522 of the multiple battery packs 51 in a one-to-one correspondence, and each of the multiple output branches 34 is in communication with the liquid outlets 523 of the multiple battery packs 51 in a one-to-one correspondence. Each of the multiple input branches 33 is connected to a control valve 40 for controlling the on / off of the input branch 33.

[0149] The liquid cooling control method of the battery pack 51 of the energy storage device 1 includes the following steps:

[0150] S21, detecting whether the multiple battery packs 51 are in thermal runaway;

[0151] S221: When none of the multiple battery packs 51 are in thermal runaway, the control valve 40 controls the multiple input branches 33 to allow flow, so that the multiple battery packs 51 are arranged in parallel.

[0152] S222. When at least one battery pack 51 among the multiple battery packs 51 is in thermal runaway, the control valve 40 connected to the battery pack 51 in thermal runaway controls the battery pack 51 in thermal runaway to be connected to the input main line 32, and the control valve 40 connected to the battery pack 51 that is not in thermal runaway controls the battery pack 51 that is not in thermal runaway to be disconnected from the input main line 32.

[0153] In this embodiment, multiple battery packs 51 are first detected for thermal runaway. If the battery packs 51 are operating normally, the control valves 40 can be used to control the parallel connection of the multiple battery packs 51 to the liquid cooling system 10, thereby reducing the power of the drive pump that drives the flow of the liquid cooling medium and thus reducing energy consumption. If a battery pack 51 is experiencing thermal runaway, the control valve 40 connected to the battery pack 51 experiencing thermal runaway connects the battery pack 51 experiencing thermal runaway to the input main line 32, while the control valves 40 connected to the battery packs 51 not experiencing thermal runaway disconnect the battery packs 51 not experiencing thermal runaway from the input main line 32. All liquid cooling medium in the input branch line 33 then flows to the battery pack 51 experiencing thermal runaway, significantly increasing the flow rate of liquid cooling medium flowing into the battery pack 51 experiencing thermal runaway, thereby effectively dissipating heat from the battery pack 51 experiencing thermal runaway and suppressing thermal runaway.

[0154] Among them, multiple battery packs 51, the liquid inlet 522 and liquid outlet 523 of the battery pack 51, the input main line 32, multiple input branches 33, the output main line 31, the output branch 34, multiple control valves 40, the liquid cooling system 10, etc. can all refer to the previous embodiments and will not be repeated here.

[0155] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An energy storage device, characterized in that, It includes multiple battery packs, an input main road, multiple input branches, an output main road and multiple output branches. Each of the multiple battery packs includes a liquid inlet and a liquid outlet. The multiple input branches are all connected to the input main road, the multiple output branches are all connected to the output main road, the multiple input branches are connected to the liquid inlets of the multiple battery packs in a one-to-one correspondence, and the multiple output branches are connected to the liquid outlets of the multiple battery packs in a one-to-one correspondence; The energy storage device further includes a series branch and a control valve. One end of the series branch is connected to the liquid outlet of one of the battery packs, and the other end of the series branch is connected to the liquid inlet of another battery pack. The control valve is used to control the switching between series connection and parallel connection of the one battery pack and the other battery pack.

2. The energy storage device according to claim 1, characterized in that, When thermal runaway occurs in the other battery pack, the control valve is used to control the state that the series branch connects the liquid outlet of the one battery pack and the liquid inlet of the other battery pack, and the one output branch connected to the liquid outlet of the one battery pack is disconnected from the output main road.

3. The energy storage device according to claim 1, wherein When thermal runaway occurs in at least one of the battery packs, the control valve is used to control the state that the series branch connects the liquid outlet of the one battery pack and the liquid inlet of the other battery pack, the one output branch connected to the liquid outlet of the one battery pack is disconnected from the output main road, and the other input branch connected to the liquid inlet of the other battery pack is disconnected from the input main road.

4. The energy storage device according to any one of claims 1 to 3, characterized in that The control valve includes multiple multi-way valves. One of the multi-way valves is provided on an output branch connected to the liquid outlet of one of the battery packs, and another multi-way valve is provided on an input branch connected to the liquid inlet of the other battery pack. One end of the series branch is connected to the one multi-way valve, and the other end of the series branch is connected to the other multi-way valve. The multi-way valve is used to control the switching between series connection and parallel connection of the one battery pack and the other battery pack.

5. The energy storage device according to claim 4, characterized in that, The output branch connected to the liquid outlet of the one battery pack includes two sub-pipes. One end of the one sub-pipe is connected to the liquid outlet of the one battery pack, and the other end of the one sub-pipe is connected to the one multi-way valve. One end of the other sub-pipe is connected to the output main road, and the other end of the other sub-pipe is connected to the one multi-way valve; The input branch connected to the liquid inlet of the other battery pack includes two sub-pipes. One end of the one sub-pipe is connected to the liquid inlet of the other battery pack, and the other end of the one sub-pipe is connected to the other multi-way valve. One end of the other sub-pipe is connected to the input main road, and the other end of the other sub-pipe is connected to the other multi-way valve; One end of the series branch is connected to the one multi-way valve, and the other end of the series branch is connected to the other multi-way valve.

6. The energy storage device according to claim 4 or 5, characterized in that, The multiple battery packs are stacked, and the two battery packs located on the outermost sides in the stacking direction of the multiple battery packs are a first battery pack and a second battery pack respectively. A multi-way valve is provided on the output branch connected to the first battery pack, and a multi-way valve is provided on the input branch connected to the second battery pack. A multi-way valve is provided on each of the input branch and the output branch connected to the battery packs located between the first battery pack and the second battery pack in the stacking direction of the multiple battery packs; The number of the series branches is multiple, and the multi-way valves on the output branches connected to one of any two adjacent battery packs and the multi-way valves on the input branches connected to the other battery pack are connected through a series branch.

7. The energy storage device according to claim 1, characterized in that, The control valve includes multiple valve switches. The valve switches are provided on all the output branches. The valve switches on the output branches are used to control the on-off of the output branches. The valve switches are provided on the series branches. The valve switches on the series branches are used to control the on-off of the series branches.

8. The energy storage device according to claim 7, characterized in that, The control valve further includes valve switches provided on the multiple input branches. The valve switches on the input branches are used to control the on-off of the input branches.

9. The energy storage device according to any one of claims 1-6, characterized in that, The multiple battery packs each include a housing and multiple battery cells. The housing includes an accommodation cavity for accommodating a liquid cooling working medium. The multiple battery cells are located in the accommodation cavity and immersed in the liquid cooling working medium. The housing is provided with the liquid inlet and the liquid outlet communicating with the accommodation cavity.

10. The energy storage device according to any one of claims 1-6, characterized in that, The multiple battery packs each include a housing, multiple battery cells and a liquid cooling plate heat exchanger located in the housing. The multiple battery cells are arranged on the liquid cooling plate heat exchanger. The liquid cooling plate heat exchanger is provided with the liquid inlet and the liquid outlet.

11. A liquid cooling control method for a battery pack of an energy storage device, characterized in that, The energy storage device includes multiple battery packs, a parallel pipeline, series branches, a control valve and a liquid cooling system. The multiple battery packs are connected to the liquid cooling system in a parallel arrangement through the parallel pipeline. The multiple battery packs are connected to the liquid cooling system in a series arrangement through the series branches. The control valve is used to control the switching of the multiple battery packs between parallel and series connections; The liquid cooling control method includes the following steps: Detect whether the multiple battery packs are thermally out of control; When none of the multiple battery packs is thermally out of control, control the multiple battery packs to be connected to the liquid cooling system in a parallel arrangement through the control valve; When at least one of the multiple battery packs is thermally out of control, control the multiple battery packs to be connected to the liquid cooling system in a series arrangement through the control valve.

12. A liquid cooling control method for a battery pack of an energy storage device, characterized in that, The energy storage device includes multiple battery packs, an input main pipeline, multiple input branches, an output main pipeline, output branches and multiple control valves. The multiple battery packs each include a liquid inlet and a liquid outlet. The multiple input branches are all communicated with the input main pipeline. The multiple output branches are all communicated with the output main pipeline. The multiple input branches are communicated with the liquid inlets of the multiple battery packs in a one-to-one correspondence. The multiple output branches are communicated with the liquid outlets of the multiple battery packs in a one-to-one correspondence. A control valve for controlling the on-off of the input branch is connected to each of the multiple input branches; The liquid cooling control method includes the following steps: Detect whether the multiple battery packs are thermally out of control; When none of the multiple battery packs are thermally out of control, the control valve controls that all of the multiple input branches can conduct, so that the multiple battery packs are arranged in parallel; When at least one of the multiple battery packs is thermally out of control, the control valve connected to the thermally out-of-control battery pack controls the thermally out-of-control battery pack to communicate with the input main path, and the control valve connected to the battery packs that are not thermally out of control controls the battery packs that are not thermally out of control to be disconnected from the input main path.

13. An energy storage system, characterized in that, It includes a power converter and the energy storage device according to any one of claims 1-10, and the power converter is connected to the energy storage device to perform power conversion on the current input to or output from the energy storage device.

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