CN117410614A - Energy storage devices and energy storage systems - Google Patents

Abstract

The invention provides an energy storage device and an energy storage system. The energy storage device comprises a battery module, a first liquid cooling plate and a second liquid cooling plate, and the first liquid cooling plate is in heat conduction connection with a first side wall of the battery module along the height direction of the battery module; the second liquid cooling plate is vertically arranged on the first liquid cooling plate, the second liquid cooling plate is contacted with the second side wall of the battery module, circulating flow channels are arranged in the first liquid cooling plate and the second liquid cooling plate, and the circulating flow channels of the first liquid cooling plate are communicated with the circulating flow channels of the second liquid cooling plate; the first side wall is perpendicular to the second side wall, the first liquid cooling plate is provided with a plurality of liquid cooling areas, circulating flow channels corresponding to the liquid cooling areas are arranged in parallel, and the flow channel length of at least one circulating flow channel corresponding to at least one liquid cooling area in the liquid cooling areas is smaller than the flow channel lengths of other circulating flow channels corresponding to other liquid cooling areas. Can be used for temperature neutralization and improves the overall temperature uniformity.

Description

Energy storage device and energy storage system

Technical Field

The present invention relates generally to the field of energy storage technology, and more particularly, to an energy storage device and an energy storage system.

Background

The existing energy storage device comprises a battery box and a plurality of battery modules which are arranged in the battery box and connected in series, so that the power supply capacity of the energy storage device is improved. The battery module of the energy storage device inevitably generates heat in the charge and discharge process and is accumulated in the battery box, and in order to avoid overhigh temperature in the battery box, a liquid cooling plate with a flow channel is usually arranged at the bottom of the battery box so as to realize heat exchange with the battery box through the flow of fluid in the flow channel. Along with the improvement of the power density of the battery module, the existing single liquid cooling plate cooling mode cannot meet the heat dissipation requirement of the battery for high power density.

Disclosure of Invention

The invention provides an energy storage device and an energy storage system, which can improve the heat dissipation effect of the energy storage device.

According to a first aspect of the present invention, there is provided an energy storage device including a battery module, a first liquid cooling plate and a second liquid cooling plate, the first liquid cooling plate being thermally connected to a first side wall of the battery module in a height direction of the battery module; the second liquid cooling plate is vertically arranged on the first liquid cooling plate, the second liquid cooling plate is in contact with the second side wall of the battery module, circulating flow passages are formed in the first liquid cooling plate and the second liquid cooling plate, and the circulating flow passages of the first liquid cooling plate are communicated with the circulating flow passages of the second liquid cooling plate; the first side wall is perpendicular to the second side wall, the first liquid cooling plate is provided with a plurality of liquid cooling areas, the circulating flow channels corresponding to the liquid cooling areas are arranged in parallel, and the flow channel length of at least one circulating flow channel corresponding to at least one liquid cooling area in the liquid cooling areas is smaller than the flow channel lengths of other circulating flow channels corresponding to other liquid cooling areas.

According to the energy storage device provided by the embodiment of the invention, the first liquid cooling plate is used for bearing the battery module, and when a cooling medium flows through the first liquid cooling flow passage of the first liquid cooling plate, heat exchange can be carried out between the cooling medium in the circulating flow passage of the first liquid cooling plate and heat generated at the bottom of the battery module. Because the heat transfer of independent bottom can make the battery module be greater along the top and the bottom difference in temperature of first direction, set up battery module in one side of the second liquid cooling board of liquid cooling subassembly, when there is the coolant flow in the second liquid cooling runner of second liquid cooling board, coolant in the circulation runner of accessible second liquid cooling board carries out the heat exchange with the heat that battery module lateral part produced, can effectively alleviate battery module bottom and top difference in temperature from top to bottom, and battery module's bottom and lateral part contact with first liquid cooling board and second liquid cooling board respectively, realize battery module bottom and lateral part simultaneous cooling, battery module has two cooling surfaces, can reduce the difference in temperature between each battery module.

Because the initial temperature of the cooling medium is the lowest, the length of the flow channel of one liquid cooling area corresponding to the circulating flow channel of the first liquid cooling plate is smaller, the cooling medium can directly enter the circulating flow channel of the second liquid cooling plate through the circulating flow channel of the first liquid cooling plate with smaller flow channel length, and the temperature of the cooling medium is slightly higher than the initial temperature at the moment, but is far lower than that of the cooling medium flowing through the circulating flow channels of the first liquid cooling plate with larger flow channel length, namely the cooling medium entering the circulating flow channel of the second liquid cooling plate is from two parts, namely the cooling medium with smaller flow channel length and lower temperature and the cooling medium with larger flow channel length and higher temperature, the two parts can be subjected to temperature neutralization, the temperature difference of the cooling medium in the circulating flow channel of the liquid inlet flow channel and the circulating flow channel of the second liquid cooling plate is reduced, and the whole temperature uniformity is improved.

In some embodiments, the projection areas of the plurality of liquid cooling areas on the first liquid cooling plate along the height direction of the battery module are different.

In this way, the plurality of liquid cooling areas are of asymmetric structures, and the cooling medium with lower temperature rise and the cooling medium with higher temperature rise are neutralized before entering the circulating flow passage of the second liquid cooling plate so as to achieve the temperature balancing effect.

In some embodiments, the circulation flow channels of the first liquid cooling plate and the circulation flow channels of the second liquid cooling plate are communicated through communication flow channels, and the flow channel lengths of the circulation flow channels of the plurality of liquid cooling areas gradually decrease along the direction approaching to the communication flow channels; and/or the circulating flow channels of the first liquid cooling plate and the circulating flow channels of the second liquid cooling plate are communicated through communication flow channels, and the flow channel sectional areas of the circulating flow channels of the plurality of liquid cooling areas are gradually reduced along the direction close to the communication flow channels.

With this arrangement, the circulation flow path length, which is relatively short from the communication flow path, is relatively short, the heat exchange with the battery module is relatively small, and the temperature of the cooling medium flowing to the communication flow path is relatively low. Because the flow of the circulating flow channel is related to the flow channel cross section and the flow channel length, under the condition of a certain flow channel cross section, the pressure difference in the circulating flow channel is changed greatly along with the increase of the flow channel length, so that the flow channel of the circulating flow channel is reduced.

In some embodiments, the first liquid cooling plate is provided with a liquid inlet channel, the second liquid cooling plate is provided with a liquid outlet channel, and the liquid inlet channel, the circulating channel of the first liquid cooling plate, the circulating channel of the second liquid cooling plate and the liquid outlet channel are communicated; the liquid inlet flow channel and the liquid outlet flow channel are positioned on the same side of the first liquid cooling plate along the length direction of the first liquid cooling plate; and/or the liquid inlet flow channel and the liquid outlet flow channel are positioned on the same side of the first liquid cooling plate along the width direction of the first liquid cooling plate.

Because the cooling medium is the initial position in inlet channel position department, and the initial temperature ratio of cooling medium is lower, and the cooling medium is the end position in outlet channel position department, and the cooling medium is higher to the temperature ratio after the heat transfer of battery module, with inlet channel and outlet channel approximately set up in same side setting, make the cooling medium in the whole cooling circuit put out in same side, the higher cooling of temperature and the lower cooling medium of temperature play the neutralization effect to a certain extent, effectively reduce the difference in temperature of cooling medium to improve the sameness of true liquid cooling subassembly.

In some embodiments, the circulating flow channels corresponding to the liquid cooling areas have different flow channel cross sections near one end of the liquid inlet flow channel.

By adopting the mode, the flow proportioning is automatically carried out according to the flow passage pressure differences of the corresponding circulating flow passages of different liquid cooling areas, so that the local excessive temperature rise can be effectively reduced, and the temperature difference is reduced.

In some embodiments, the circulating flow channel corresponding to each liquid cooling zone comprises a plurality of cooling units arranged in series; the liquid inlet channel is communicated with the cooling unit close to the liquid inlet channel through a main channel, and the extending directions of the main channel and the liquid inlet channel are different.

The cooling units arranged in series increase the overall flow path length of the circulating flow path, so that the circulating flow path covers the corresponding area of the battery module as much as possible. The cooling medium flowing out of the inlet flow channel is not directly introduced into the main channel, but has a certain bending so as to be divided into multiple channels, and then enters the corresponding liquid cooling zone through the main body.

In some embodiments, the cooling unit comprises a plurality of cooling branches arranged in parallel; the cooling branch is arranged in an extending way along the length direction of the first liquid cooling plate; or, the cooling branch is extended along the width direction of the first liquid cooling plate.

The cooling branches arranged in parallel divide the main path into a plurality of tiny branches, so that the contact area between the cooling medium and the wall surface of the cold plate of the first liquid cooling plate can be increased, and the heat exchange effect is enhanced.

In some embodiments, the circulation flow channel of the first liquid cooling plate is communicated with the circulation flow channel of the second liquid cooling plate through a communication flow channel; the two adjacent cooling units are communicated through a cooling main path, and turbulence pieces are arranged in the cooling units and/or the cooling main path; the first liquid cooling plate is provided with the turbulence piece at one side close to the communication flow passage.

The turbulence piece can increase turbulence of the cooling medium, so that the cooling medium with different temperatures flowing out of each cooling branch is uniformly mixed and then flows into the next cooling unit or the next cooling branch. Because the cooling medium flowing out of the communication flow passage needs to flow upwards to the circulating flow passage of the second liquid cooling plate along the height direction of the battery module, the disturbance piece is arranged at the position near the communication flow passage, and the disturbance piece can improve the disturbance resistance of the cooling medium, so that the flow speed of the cooling medium is increased, and the cooling medium can be quickly rushed upwards to the circulating flow passage of the second liquid cooling plate along the height direction of the battery module.

In some embodiments, the energy storage device further comprises: one end of the supporting piece in the height direction of the battery module is connected with the first liquid cooling plate, and the other end of the supporting piece is connected with the second liquid cooling plate; the first liquid cooling plate, the second liquid cooling plate and the supporting piece are of an integrated structure.

The support piece is used for lifting the height of the second liquid cooling plate, the second liquid cooling plate can cool the position of the side part of the battery module, and the temperature difference between the upper part and the lower part of the battery module can be effectively relieved. Compared with the independent setting mode of bottom and lateral part cooling, the advantage of collecting bottom cooling and lateral part cooling adopts the mode of bottom and lateral part cooling integration, need not to increase extra connecting line and sealing joint etc. when make full use of box inner space, can also reduce manufacturing cost.

In some embodiments, the energy storage device further comprises a support member and a connecting pipeline, one end of the support member in the height direction of the battery module is connected to the first liquid cooling plate, one of the other end of the support member in the height direction of the battery module and the second liquid cooling plate is provided with a positioning column, the other end of the support member in the height direction of the battery module is provided with a positioning hole, and the positioning column penetrates through the positioning hole; the connecting pipeline is located between the first liquid cooling plate and the second liquid cooling plate, the connecting pipeline is detachably connected with the first liquid cooling plate and the second liquid cooling plate respectively, a communication runner is arranged in the connecting pipeline, and the circulating runner of the first liquid cooling plate is communicated with the circulating runner of the second liquid cooling plate through the communication runner.

Adopt the detachable design between first liquid cooling board and the second liquid cooling board, when damage appears in one of them liquid cooling board, be convenient for change and maintain. Under the cooperation of reference column and locating hole, make things convenient for the second liquid cooling board to dock through support piece and first liquid cooling board, guarantee the location accuracy between first liquid cooling board and the second liquid cooling board. In addition, still accessible structural adhesive is fixed between reference column and locating hole, improves fixed effect.

In some embodiments, the energy storage device further includes a separator, the separator is disposed in the circulation flow channel of the second liquid cooling plate, the separator is disposed along an extending direction of the circulation flow channel of the second liquid cooling plate, the separator separates the circulation flow channel of the second liquid cooling plate into two sub flow channels, and the two sub flow channels are respectively and correspondingly connected with the second side walls of the two battery modules in a heat conduction manner.

Two battery modules located in second liquid cooling board both sides accessible two sub-runners cool off simultaneously, and the second liquid cooling board adopts two-sided refrigerated mode, increases heat transfer area, makes every battery module all receive the cooling of a side alone, and the radiating effect is good.

According to a second aspect of the present invention, an embodiment of the present invention further provides an energy storage system, including an electric device and the energy storage device, where the energy storage device supplies power to the electric device.

The temperature in the box body is effectively reduced through the cooling medium flowing in the circulating flow channel of the first liquid cooling plate and the circulating flow channel of the second liquid cooling plate, so that the energy storage device is at a lower temperature, the potential safety hazard is reduced while the charge and discharge performance of the energy storage device is guaranteed, and the use reliability of the whole energy storage device is improved.

Drawings

For a better understanding of the invention, reference may be made to the embodiments illustrated in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present invention. In addition, the relevant elements or components may have different arrangements as known in the art. Furthermore, in the drawings, like reference numerals designate identical or similar parts throughout the several views. The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Wherein:

fig. 1 is a schematic structural diagram of an energy storage system according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of an energy storage device according to a first embodiment of the present invention;

FIG. 3 is a schematic diagram of a partially exploded structure of an energy storage device according to a first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a first liquid cooling plate in an energy storage device according to a first embodiment of the present invention;

fig. 5 shows a second schematic structural diagram of a first liquid cooling plate in the energy storage device according to the first embodiment of the present invention;

fig. 6 is a schematic structural diagram of a first side plate of an energy storage device according to a first embodiment of the present invention;

fig. 7 is a schematic structural diagram of a second side plate of the energy storage device according to the first embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating a partial explosion of a liquid cooling assembly in an energy storage device according to a second embodiment of the present invention;

fig. 9 is a schematic cross-sectional view of a second liquid cooling plate in an energy storage device according to a third embodiment of the present invention.

Wherein reference numerals are as follows:

100. an energy storage device; 200. an electric energy conversion device; 300. an electric device;

10. a case; 20. a battery module; 30. a liquid cooling assembly;

301. a circulation flow channel; 3011. a sub-runner; 302. a communicating flow passage; 303. a liquid inlet flow channel; 304. a liquid outlet channel;

31. A first liquid cooling plate; 311. a liquid cooling zone; 3111. a first liquid-cooled zone; 3112. a second liquid cooling zone; 312. a cooling unit; 3121. a first cooling unit; 3122. a second cooling unit; 3123. a third cooling unit; 3124. a fourth cooling unit; 3125. a fifth cooling unit; 3120. a cooling branch; 313. a main road; 3131. a first main path; 3132. a second main path; 314. a spoiler; 315. a cooling main path; 316. positioning columns;

32. a second liquid cooling plate; 321. a first side plate; 322. a second side plate; 323. a connecting plate; 33. a support; 331. positioning holes; 34. a connecting pipeline; 35. a partition board.

Detailed Description

The technical solutions in the exemplary embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the exemplary embodiments of the present invention. The example embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, and it should be understood that various modifications and changes can be made to the example embodiments without departing from the scope of the invention.

In the description of the present invention, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless explicitly specified or limited otherwise; the term "plurality" refers to two or more than two; the term "and/or" includes any and all combinations of one or more of the associated listed items. In particular, references to "the/the" object or "an" object are likewise intended to mean one of a possible plurality of such objects.

Unless specified or indicated otherwise, the terms "connected," "fixed," and the like are to be construed broadly and are, for example, capable of being fixedly connected, detachably connected, or integrally connected, electrically connected, or signally connected; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to the specific circumstances.

Further, in the description of the present invention, it should be understood that the terms "upper", "lower", "inner", "outer", and the like in the exemplary embodiments of the present invention are described in terms of the drawings, and should not be construed as limiting the exemplary embodiments of the present invention. It will also be understood that in the context of an element or feature being connected to another element(s) "upper," "lower," or "inner," "outer," it can be directly connected to the other element(s) "upper," "lower," or "inner," "outer," or indirectly connected to the other element(s) "upper," "lower," or "inner," "outer" via intervening elements.

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted.

Because of the strong timeliness and space properties of energy sources required by people, in order to reasonably utilize the energy sources and improve the utilization rate of the energy, one energy form needs to be stored by one medium or equipment and then is converted into another energy form, and then is released in a specific energy form based on future application requirements. As is well known, the purpose of generating green electric energy is achieved by mainly replacing fossil energy with green energy.

The existing green energy mainly comprises light energy, wind energy, water potential and the like, and the problems of strong intermittence and large fluctuation of the light energy, the wind energy and the like generally exist, so that the voltage of a green power grid is unstable (insufficient electricity is used in a peak and too much electricity is used in a valley), and the unstable voltage can cause damage to the electric power, so that the problem of 'wind abandoning and light abandoning' is possibly caused by insufficient electricity demand or insufficient power grid receiving capability.

To solve the problem of insufficient power demand or insufficient power grid capacity, the energy storage device 100 must be relied upon. That is, the energy storage device 100 converts electric energy into other energy to store the energy, and when needed, the energy storage device 100 converts the stored energy into electric energy to release, in short, the energy storage device 100 is similar to a large-sized "charge pal", when the light energy and the wind energy are sufficient, the electric energy is stored, and when needed, the stored electric energy is released.

The present energy storage (i.e. energy storage) has a wide application scenario, including aspects of power generation side energy storage, grid side energy storage, renewable energy grid-connected energy storage, user side energy storage, and the like, and the types of the corresponding energy storage device 100 include:

(1) The large energy storage container applied to the energy storage scene at the power grid side can be used as a high-quality active and reactive power regulation power supply in the power grid, so that the load matching of electric energy in time and space is realized, the renewable energy consumption capability is enhanced, and the large energy storage container has great significance in the aspects of standby of a power grid system, relieving peak load power supply pressure and peak regulation and frequency modulation;

(2) The main operation modes of the small and medium-sized energy storage electric cabinet applied to the industrial and commercial energy storage scenes (banks, shops and the like) at the user side and the household small-sized energy storage box applied to the household energy storage scene at the user side are peak clipping and valley filling. Because of the large price difference of the electricity charge at the peak-valley position according to the electricity consumption requirement, after the energy storage equipment is arranged by a user, in order to reduce the cost, the energy storage cabinet/box is charged usually in the electricity price valley period; and in the peak period of electricity price, the electricity in the energy storage equipment is released for use, so that the purpose of saving electricity charge is achieved. In addition, in remote areas, and areas where natural disasters such as earthquakes and hurricanes are high, the presence of the household energy storage device 100 corresponds to the user providing backup power for the user and the power grid, and avoids inconvenience caused by frequent power failure due to disasters or other reasons.

Taking a household energy storage scenario in user side energy storage as an example, fig. 1 shows a household energy storage system, where the energy storage system includes an energy storage device 100 and an electric energy conversion device 200 (such as a photovoltaic panel), and an electric device 300 (such as a street lamp, a household appliance, etc.), where the energy storage device 100 is a small-sized energy storage box, and may be installed on an outdoor wall by a wall-hanging manner. Specifically, the power conversion device 200 may convert solar energy into electric energy during the low electricity price period, and store the electric energy by the energy storage device 100, so as to supply the electric equipment 300 for use during the high electricity price period or supply the electric equipment 300 for use during the power outage/power failure period of the power grid.

In combination with the above-mentioned case of performing energy storage by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage device 100 includes at least one chemical battery, and chemical elements in the chemical battery are used as an energy storage medium, so as to implement a charging and discharging process through chemical reaction or change of the energy storage medium. In short, the electric energy generated by light energy and wind energy is stored in at least one group of chemical batteries through chemical reaction or change of the energy storage medium, and when the use of external electric energy reaches a peak, the electric quantity stored in at least one group of chemical batteries is released for use through the chemical reaction or change of the energy storage medium, or is transferred to a place where the electric quantity is short for use.

The electric device 300 may also be an energy storage device, a vehicle, an energy storage container, etc., and the energy storage device 100 supplies power to the electric device 300. Thus, in combination with the above, the present application ensures the stability of the operation of the electric device 300 when the energy storage device 100 has stable charging and discharging performance.

The embodiment provides an energy storage device 100, and the energy storage device 100 may be a battery module 20, a battery pack, a battery box, a battery system, or the like, which is formed by single batteries. The single battery may be a lithium ion secondary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, etc., and the single battery may be a cylinder, a flat body, a cuboid, etc., which is not limited in the embodiment of the present application.

As shown in fig. 2, the energy storage device 100 includes a case 10 (a bottom plate of the case 10), a liquid cooling assembly 30, and a battery module 20, and the liquid cooling assembly 30 and the battery module 20 are fixedly disposed in the case 10.

As shown in fig. 3, the liquid cooling assembly 30 includes a first liquid cooling plate 31 and a second liquid cooling plate 32, and the first liquid cooling plate 31 is thermally connected to a first side arm of the battery module 20 along the height direction of the battery module 20 (the height direction may be identified by H). The second liquid cooling plate 32 is vertically arranged on the first liquid cooling plate 31 and is in contact with the second side wall of the battery module 20, the first liquid cooling plate 31 and the second liquid cooling plate 32 are internally provided with a circulating runner 301, the circulating runner 301 of the first liquid cooling plate 31 is communicated with the circulating runner 301 of the second liquid cooling plate 32, a cooling medium circularly flows in the circulating runner 301, and the cooling medium can be cooling water, cooling liquid or other media with cooling functions.

The first side wall of the battery module 20 along the height direction of the battery module 20 may specifically refer to the bottom wall, or the top wall and the bottom wall of the battery module 20. Since the second liquid cooling plate 32 is vertically disposed on the first liquid cooling plate 31, the second side wall of the battery module 20 may specifically refer to a circumferential side wall of the battery module 20, and specifically a side wall of the battery module 20 along the length direction (may be identified by L) and/or the length direction (may be identified by W) of the first liquid cooling plate 31.

The battery module 20 is disposed on the first liquid cooling plate 31 of the liquid cooling assembly 30, and the first liquid cooling plate 31 is used for carrying the battery module 20, and when a cooling medium flows through the first liquid cooling flow channel of the first liquid cooling plate 31, heat exchange is performed between the cooling medium in the circulation flow channel 301 of the first liquid cooling plate 31 and heat generated at the bottom of the battery module 20. Because the temperature difference between the top and the bottom of the battery module 20 along the first direction is relatively large due to the heat exchange at the bottom alone, the battery module 20 is arranged on one side of the second liquid cooling plate 32 of the liquid cooling assembly 30, when a cooling medium flows in the second liquid cooling flow passage of the second liquid cooling plate 32, the cooling medium in the circulating flow passage 301 of the second liquid cooling plate 32 can exchange heat with the heat generated by the side part of the battery module 20, the temperature difference between the bottom and the top of the battery module can be effectively relieved, the bottom and the side part of the battery module 20 are respectively contacted with the first liquid cooling plate 31 and the second liquid cooling plate 32 correspondingly, the bottom and the side part of the battery module 20 are simultaneously cooled, and the battery module 20 is provided with two cooling surfaces, so that the temperature difference between each battery module 20 can be reduced.

For the energy storage device 100 with the liquid cooling assembly 30, the temperature in the box 10 is effectively reduced by utilizing the cooling medium flowing in the circulating flow channel 301 of the first liquid cooling plate 31 and the circulating flow channel 301 of the second liquid cooling plate 32, so that the energy storage device 100 is at a lower temperature, the charge and discharge performance of the energy storage device 100 is ensured, the potential safety hazard is reduced, and the use reliability of the whole energy storage device 100 is improved.

As shown in fig. 4, the first liquid cooling plate 31 has a plurality of liquid cooling areas 311, and the circulation flow paths 301 of the first liquid cooling plate 31 corresponding to the plurality of liquid cooling areas 311 are arranged in parallel.

The plurality of liquid cooling areas 311 correspond to the plurality of branches, so that the cooling medium introduced from the liquid inlet flow channel 303 is divided into the plurality of branches, and the liquid cooling medium is split. The plurality of liquid cooling regions 311 correspond to the partial regions of the battery module 20, respectively, and can exchange heat with the partial regions, respectively. Since the circulation flow channels 301 of the first liquid cooling plates 31 corresponding to the plurality of liquid cooling areas 311 are arranged in parallel, heat exchange in each local area of the battery module 20 is independent and does not interfere with each other.

If the lengths of the circulation flow paths 301 of the first liquid cooling plates 31 corresponding to the respective liquid cooling areas 311 are the same, the temperatures of the cooling medium entering the circulation flow paths 301 of the second liquid cooling plates 32 through the circulation flow paths 301 of the first liquid cooling plates 31 corresponding to the respective liquid cooling areas 311 are approximately the same, and the initial temperatures of the cooling medium when the cooling medium is located in the liquid inlet flow paths 303 are relatively different, so that the temperature uniformity of the cooling medium is relatively poor.

For this reason, the length of at least one circulation flow channel 301 corresponding to at least one liquid cooling zone 311 of the plurality of liquid cooling zones 311 provided in the present embodiment is smaller than the lengths of other circulation flow channels 301 corresponding to other liquid cooling zones 311.

Since the cooling medium is located at the lowest initial temperature of the liquid inlet channel 303, the cooling medium can directly enter the circulating channel 301 of the second liquid cooling plate 32 through the circulating channel 301 of the first liquid cooling plate 31 with smaller channel length, and at this time, the temperature of the cooling medium is slightly higher than the initial temperature, but far lower than the cooling medium flowing through the circulating channels 301 of the first liquid cooling plate 31 with larger channel length, namely, the cooling medium entering the circulating channels 301 of the second liquid cooling plate 32 comes from two parts, namely, the cooling medium with smaller channel length and lower temperature and the cooling medium with larger channel length and higher temperature, respectively, and the two parts can perform temperature neutralization, so that the temperature difference between the cooling medium in the liquid inlet channel 303 and the circulating channels 301 of the second liquid cooling plate 32 is reduced, and the overall temperature uniformity of the liquid cooling assembly 30 is improved.

In one embodiment, the projected areas of the plurality of liquid cooling areas 311 on the first liquid cooling plate 31 along the height direction of the battery module 20 are different.

The area of the liquid cooling region 311 with smaller projection area corresponding to the battery module 20 is smaller, the heat exchange with the battery module 20 is smaller, and the temperature rise of the cooling medium after the heat exchange is lower; the liquid cooling region 311 having a larger projected area corresponds to a larger region of the battery module 20, and is sufficiently heat-exchanged with the battery module 20, and the temperature rise of the cooling medium after heat exchange is relatively high. In this way, the plurality of liquid cooling areas 311 are in an asymmetric structure, and the cooling medium with lower temperature rise and the cooling medium with higher temperature rise are neutralized before entering the circulation flow channel 301 of the second liquid cooling plate 32, so as to achieve the temperature equalization effect.

Illustratively, the plurality of liquid cooling zones 311 includes a first liquid cooling zone 3111 and a second liquid cooling zone 3112, and a length of the circulating flow channel 301 corresponding to the second liquid cooling zone 3112 is smaller than a length of the circulating flow channel 301 corresponding to the first liquid cooling zone 3111. The first liquid cooling zone 3111 and the second liquid cooling zone 3112 are of asymmetric configuration, i.e., the first liquid cooling zone 3111 may be referred to as a large circulation, and the second liquid cooling zone 3112 may be referred to as a small circulation.

Meanwhile, the projected area of the second liquid cooling zone 3112 with respect to the first liquid cooling plate 31 is smaller than the projected area of the first liquid cooling zone 3111 with respect to the first liquid cooling plate 31, for example, the ratio of the projected area of the second liquid cooling zone 3112 with respect to the first liquid cooling plate 31 to the projected area of the first liquid cooling zone 3111 with respect to the first liquid cooling plate 31 may be selected to be 1:2.

It is to be understood that both the first liquid cooling zone 3111 and the second liquid cooling zone 3112 may be disposed side by side on the first liquid cooling plate 31, or the second liquid cooling zone 3112 may be disposed inside the first liquid cooling zone 3111, i.e. the first liquid cooling zone 3111 is half-wrapped around the second liquid cooling zone 3112.

In one embodiment, the circulation flow channel 301 of the first liquid cooling plate 31 is communicated with the circulation flow channel 301 of the second liquid cooling plate 32 through a communication flow channel 302, and the projection area of the plurality of liquid cooling areas 311 with respect to the first liquid cooling plate 31 gradually decreases along the direction approaching the communication flow channel 302.

That is, the projected area of the liquid cooling region 311, which is closer to the communication flow passage 302, with respect to the first liquid cooling plate 31 is smaller, the temperature rise of the cooling medium after heat exchange with the bottom of the battery module 20 is lower, and the cooling medium can be rapidly and timely supplied into the communication flow passage 302, thereby improving the temperature uniformity of the cooling medium.

Specifically, the flow path lengths of the circulation flow paths 301 of the plurality of liquid cooling zones 311 gradually decrease in the direction approaching the communication flow path 302. With this arrangement, the circulation flow path 301, which is closer to the communication flow path 302, has a smaller flow path for the cooling medium, and the cooling medium flows to the communication flow path 302 at a lower temperature with less heat exchange with the battery module 20.

Specifically, the flow passage sectional area of the circulation flow passage 301 of the plurality of liquid-cooling regions 311 gradually decreases in the direction approaching the communication flow passage 302.

Since the flow rate of the circulation flow channel 301 is related to the flow channel cross section and the flow channel length, under the condition that the flow channel cross section is constant, the pressure difference in the circulation flow channel 301 is changed greatly along with the increase of the flow channel length, so that the flow channel of the circulation flow channel 301 is reduced, therefore, the circulation flow channel 301 with a larger flow channel length is increased to play a role of balancing the flow rate, the flow rates of the different liquid cooling areas 311 corresponding to the circulation flow channel 301 are approximately the same, and the overall temperature uniformity is further improved.

In one embodiment, the flow cross sections of the circulating flow channels 301 corresponding to the adjacent two liquid cooling regions 311 near one end of the liquid inlet flow channel 303 are different. In this way, the flow proportioning is automatically carried out according to the flow passage pressure difference of the corresponding circulating flow passage 301 of different liquid cooling areas 311, so that the local excessive temperature rise can be effectively reduced, and the temperature difference is reduced.

In one embodiment, as shown in fig. 3 to 4, the first liquid cooling plate 31 is provided with a liquid inlet channel 303, the second liquid cooling plate 32 is provided with a liquid outlet channel 304, the liquid inlet channel 303, the circulating channel 301 of the first liquid cooling plate 31, the circulating channel 301 of the second liquid cooling plate 32 and the liquid outlet channel 304 are communicated, a cooling medium is injected from the liquid inlet channel 303, and is discharged from the liquid outlet channel 304 after flowing through the circulating channel 301 of the first liquid cooling plate 31 and the circulating channel 301 of the second liquid cooling plate 32, so as to complete the heat exchange process of the cooling medium.

Illustratively, the liquid inlet channel 303 is disposed on the first liquid cooling plate 31, the liquid outlet channel 304 is disposed on the second liquid cooling plate 32, the liquid inlet channel 303, the circulating channel 301 of the first liquid cooling plate 31, the circulating channel 301 of the second liquid cooling plate 32 and the liquid outlet channel 304 are sequentially communicated, the cooling medium introduced from the liquid inlet channel 303 enters the circulating channel 301 of the first liquid cooling plate 31 first, so that the cooling medium in the circulating channel 301 of the first liquid cooling plate 31 exchanges heat with the bottom of the battery module 20, the cooling medium flowing out of the circulating channel 301 of the first liquid cooling plate 31 is discharged from the liquid outlet channel 304 through the circulating channel 301 of the second liquid cooling plate 32, and the cooling medium in the circulating channel 301 of the second liquid cooling plate 32 exchanges heat with the side of the battery module 20.

Of course, the positions of the liquid inlet channel 303 and the liquid outlet channel 304 may also be interchanged, that is, the liquid inlet channel 303 is disposed on the second liquid cooling plate 32, the liquid outlet channel 304 is disposed on the first liquid cooling plate 31, or the liquid inlet channel 303 and the liquid outlet channel 304 may be disposed on the first liquid cooling plate 31 at the same time, or the liquid inlet channel 303 and the liquid outlet channel 304 may be disposed on the second liquid cooling plate 32 at the same time.

Wherein, the liquid inlet channel 303 and the liquid outlet channel 304 are located at the same side of the first liquid cooling plate 31 along the length direction of the first liquid cooling plate 31; and/or the liquid inlet channel 303 and the liquid outlet channel 304 are positioned on the same side of the first liquid cooling plate 31 along the width direction of the first liquid cooling plate 31. In other words, the projection of the liquid inlet flow channel 303 with respect to the first liquid cooling plate 31 and the projection of the liquid outlet flow channel 304 with respect to the first liquid cooling plate 31 are at least partially overlapped.

Because the cooling medium is at the initial position at the position of the liquid inlet channel 303, the initial temperature of the cooling medium is lower, and the cooling medium is at the end position at the position of the liquid outlet channel 304, the temperature of the cooling medium after heat exchange of the battery module 20 is higher, the liquid inlet channel 303 and the liquid outlet channel 304 are approximately arranged on the same side, so that the cooling medium in the whole cooling loop enters and exits from the same side, the cooling medium with higher temperature and the cooling medium with lower temperature play a neutralizing role to a certain extent, the temperature difference of the cooling medium is effectively reduced, and the temperature uniformity of the true liquid cooling assembly 30 is improved.

Illustratively, the liquid inlet channel 303 is located on the right side of the first liquid cooling plate 31 along the width direction of the first liquid cooling plate 31, the communication channel 302 is located on the left side of the first liquid cooling plate 31 along the width direction of the first liquid cooling plate 31, so that the cooling medium is introduced from the right side of the first liquid cooling plate 31, passes through the circulation channel 301 of the first liquid cooling plate 31, enters the circulation channel 301 of the second liquid cooling plate 32 from the left side of the first liquid cooling plate 31, and finally flows out from the right side of the second liquid cooling plate 32. Since the temperature of the cooling medium in the circulation flow channel 301 of the first liquid cooling plate 31 is relatively low at the right side and relatively high at the left side, and the temperatures of the cooling medium at the left side and the right side of the circulation flow channel 301 of the second liquid cooling plate 32 are just opposite, the neutralization effect is achieved, and therefore the temperature difference of the cooling medium is effectively reduced.

In one embodiment, as shown in fig. 5, each of the circulating channels 301 corresponding to the liquid cooling regions 311 includes a plurality of cooling units 312 arranged in series, and the overall channel length of the circulating channel 301 is increased, so that the circulating channel 301 covers as much area corresponding to the battery module 20 as possible.

Illustratively, the first liquid cooling zone 3111 has a first cooling unit 3121, a second cooling unit 3122, and a third cooling unit 3123 connected in series with each other, the liquid inlet flow channel 303 is in communication with the first cooling unit 3121, the third cooling unit 3123 is in communication with the circulation flow channel 301 of the second liquid cooling plate 32, and the second cooling unit 3122 is located between the first cooling unit 3121 and the third cooling unit 3123. The three cooling units 312, which are disposed in series, may increase the coverage area of the battery module 20, thereby improving the heat exchange effect of the battery module 20.

Illustratively, the second liquid cooling zone 3112 includes a fourth cooling unit 3124 and a fifth cooling unit 3125 connected in series with each other, the fourth cooling unit 3124 being in communication with the liquid inlet channel 303, the fifth cooling unit 3125 being in communication with the circulation channel 301 of the second liquid cooling plate 32. The second liquid cooling zone 3112 has only two cooling units 312 arranged in series, and has less heat exchange with the battery module 20, so that the temperature rise of the cooling medium is small and can be timely supplemented into the communication flow channel 302, and the overall temperature uniformity is improved.

In one embodiment, the inlet flow channel 303 is connected to the cooling unit 312 adjacent to the inlet flow channel 303 by a main channel 313, and the main channel 313 and the inlet flow channel 303 are different in extending direction. In this way, the cooling medium flowing out of the inlet flow channel 303 does not directly enter the main channel 313, but rather has a certain bend so as to be divided into multiple channels so as to enter the corresponding liquid cooling zone 311 through the main body.

Illustratively, the inlet flow path 303 communicates with the first cooling unit 3121 through the first main path 3131, and the inlet flow path 303 communicates with the fourth cooling unit 3124 through the second main path 3132. The extending directions of the first main path 3131 and the liquid inlet flow path 303 are different, and the extending directions of the second main path 3132 and the liquid inlet flow path 303 are different. For example, the liquid inlet flow path 303 extends in the longitudinal direction of the first liquid cooling plate 31, the first main path 3131 and the second main path 3132 extend in the width direction of the first liquid cooling plate 31, and the cooling medium flowing out from the liquid inlet flow path 303 is divided into left and right parts in the width direction of the first liquid cooling plate 31 so as to enter the large circulation and the small circulation, respectively.

In one embodiment, cooling unit 312 includes a plurality of cooling branches 3120 arranged in parallel. The plurality of cooling branches 3120 arranged in parallel divide the main path 313 into a plurality of fine branches, so that the contact area between the cooling medium and the wall surface of the first liquid cooling plate 31 can be increased, and the heat exchange effect can be enhanced.

In one embodiment, two adjacent cooling units 312 are in communication via a cooling main path 315. That is, the cooling branches 3120 arranged in parallel are collected into the cooling main path 315 at intervals, and the cooling main path 315 realizes that the cooling medium in the cooling branches 3120 is redistributed to the cooling branches 3120 of the next cooling unit 312 after being mixed, so as to ensure the uniformity of the temperature of the cooling medium. Meanwhile, the cooling medium can be guaranteed to be remixed through the cooling main path 315 at intervals, and the condition that the temperature difference is increased due to the fact that the temperature of the liquid cooling medium in a certain cooling branch path 3120 is too high is avoided.

In one embodiment, cooling branch 3120 extends along the length direction (denoted by L) of first liquid cooling plate 31; alternatively, the cooling branch 3120 is extended in the width direction (denoted by W) of the first liquid cooling plate 31.

Illustratively, after the cooling medium in the inlet flow channel 303 is introduced in the L direction, the cooling medium is divided into a first main path 3131 and a second main path 3132 flowing in the W direction, the cooling medium in the first main path 3131 flows to the first cooling unit 3121, the cooling medium in the cooling branch 3120 of the first cooling unit 3121 flows in the W direction, then flows to the second cooling unit 3122, the cooling branch 3120 of the second cooling unit 3122 flows in the L direction, then flows to the third cooling unit 3123, the cooling branch 3120 of the third cooling unit 3123 flows in the L direction, and finally enters the circulation flow channel 301 of the second liquid cooling plate 32 through the communication flow channel 302. The cooling medium in the second main path 3132 flows to the fourth cooling unit 3124, flows in the W direction in the cooling branch path 3120 of the fourth cooling unit 3124, then flows to the fifth cooling unit 3125, flows in the L direction in the cooling branch path 3120 of the fifth cooling unit 3125, and preferably enters the circulation flow path 301 of the second liquid cooling plate 32 through the communication flow path 302.

In one embodiment, a spoiler 314 is also disposed within the cooling unit 312 and/or the cooling main path 315. The turbulence member 314 can increase turbulence of the cooling medium, so that the cooling medium with different temperatures flowing out of each cooling branch 3120 is uniformly mixed and then flows into the next cooling unit 312 or the next cooling branch 3120. The number of the turbulence pieces 314 can be cylindrical, the number of the turbulence pieces 314 can be multiple, and the areas around the turbulence pieces 314 form a pressure equalizing cavity, so that the turbulence and temperature uniformity effects are further improved.

Wherein, a spoiler 314 is disposed on a side of the first liquid cooling plate 31 near the communication channel 302.

Since the cooling medium flowing out of the communication flow passage 302 is required to flow upward into the circulation flow passage 301 of the second liquid cooling plate 32 in the height direction of the battery module 20, the turbulence piece 314 is provided in the vicinity of the communication flow passage 302, and the turbulence piece 314 can increase the turbulence resistance of the cooling medium, thereby increasing the flow velocity of the cooling medium, so that the cooling medium can be rapidly flushed upward into the circulation flow passage 301 of the second liquid cooling plate 32 in the height direction of the battery module 20.

In one embodiment, as shown in fig. 3 and 6, the energy storage device 100 further includes a support member 33, one end of the support member 33 along the height direction of the battery module 20 is connected to the first liquid cooling plate 31, the other end is connected to the second liquid cooling plate 32, and a communication flow channel 302 is disposed in the support member 33. The support member 33 is equivalent to lifting the height of the second liquid cooling plate 32, and the second liquid cooling plate 32 can cool the position of the side part of the battery module 20, so that the temperature difference between the upper and lower sides of the battery module 20 can be effectively relieved.

Wherein, the first liquid cooling plate 31, the second liquid cooling plate 32 and the supporting member 33 are integrally formed.

Compared with the independent setting mode of the bottom and side cooling, the integrated mode of the bottom and side cooling is adopted, the additional connecting pipelines 34, sealing joints and the like are not needed, the internal space of the box 10 is fully utilized, and meanwhile, the production cost can be reduced.

In one embodiment, as shown in fig. 3 and fig. 6-7, the second liquid cooling plate 32 is approximately in a U-shaped structure, the second liquid cooling plate 32 includes a first side plate 321, a second side plate 322 and a connecting plate 323, the first side plate 321 and the second side plate 322 are respectively disposed on two sides of the first liquid cooling plate 31 along the W direction, the connecting plate 323 is disposed between the first side plate 321 and the second side plate 322, and stability is increased relative to a tail connection structure of the first side plate 321 and the second side plate 322, so that the second liquid cooling plate 32 is not easy to deform. The first and second side plates 321 and 322 extend in the L direction to cool the side surfaces of the battery module 20 in the W direction, and the middle plate extends in the W direction to cool the side surfaces of the battery module 20 in the L direction.

The circulation flow channels 301 of the first side plate 321 and the second side plate 322 are similar to the circulation flow channels 301 of the first liquid cooling plate 31, and may also have a plurality of cooling units 312 disposed in series, where two adjacent cooling units 312 are communicated through the cooling main path 315, and the cooling units 312 include a plurality of cooling branches 3120 disposed in parallel. The number and arrangement of the cooling units 312 and the cooling branches 3120 can be adjusted according to actual production requirements, so detailed description thereof is omitted.

The first side plate 321 is disposed on one side of the first liquid cooling plate 31 along W direction and away from the liquid inlet channel 303, and the liquid outlet channel 304 is disposed on the second side plate 322. The communication flow channel 302 is disposed between the bottom of the first side plate 321 and the first liquid cooling plate 31, and the cooling medium flowing out of the communication flow channel 302 enters the circulation flow channel 301 of the first side plate 321, then enters the circulation flow channel 301 of the second side plate 322 through the circulation flow channel 301 of the connection plate 323, and finally is discharged from the liquid outlet flow channel 304.

Example two

The present embodiment is similar to the first embodiment, and only the difference is the connection between the first liquid cooling plate 31 and the second liquid cooling plate 32, and other structures can be referred to in the first embodiment.

As shown in fig. 8, the energy storage device 100 further includes a support member 33, one end of the support member 33 along the height direction of the battery module 20 is connected to the first liquid cooling plate 31, one of the other end of the support member 33 along the height direction of the battery module 20 and the second liquid cooling plate 32 is provided with a positioning column 316, the other end is provided with a positioning hole 331, and the positioning column 316 is disposed through the positioning hole 331.

Adopt the detachable design between first liquid cooling board 31 and the second liquid cooling board 32, when damage appears in one of them liquid cooling board, be convenient for change and maintain. Under the cooperation of the positioning column 316 and the positioning hole 331, the second liquid cooling plate 32 is convenient to butt joint with the first liquid cooling plate 31 through the supporting piece 33, and positioning accuracy between the first liquid cooling plate 31 and the second liquid cooling plate 32 is guaranteed. In addition, the fixing effect is improved by fixing the positioning posts 316 and the positioning holes 331 through structural adhesive.

The number of the positioning columns 316 and the positioning holes 331 is plural, the positioning columns 316 and the positioning holes 331 are correspondingly disposed, and the positioning columns 316 are disposed along the circumferential direction of the second liquid cooling plate 32.

An accommodating space is formed between the first liquid cooling plate 31 and the second liquid cooling plate 32, when the battery module 20 is installed, the battery module 20 is firstly placed on the first liquid cooling plate 31 and corresponds to the position of the accommodating space, then the second liquid cooling plate 32 with the supporting piece 33 is placed on the first liquid cooling plate 31, and the positioning column 316 and the positioning hole 331 are inserted in opposite directions, so that the whole assembly is convenient.

In one embodiment, as shown in fig. 8, the energy storage device 100 further includes a connection pipeline 34, the connection pipeline 34 is located between the first liquid cooling plate 31 and the second liquid cooling plate 32, the connection pipeline 34 is detachably connected to the first liquid cooling plate 31 and the second liquid cooling plate 32 respectively, a communication flow channel 302 is disposed in the connection pipeline 34, and a circulation flow channel 301 of the first liquid cooling plate 31 is communicated with a circulation flow channel 301 of the second liquid cooling plate 32 through the communication flow channel 302.

Specifically, the connecting pipeline 34 is a flexible pipe, the lower end of the connecting pipeline 34 is mounted on the joint of the first liquid cooling plate 31 through a clamp, the upper end of the connecting pipeline 34 is connected with a female head, the circulating runner 301 of the second liquid cooling plate 32 is provided with a male head corresponding to the female head, and the male head and the female head are detachably connected through a buckle structure. The cooling medium is introduced into the circulation flow path 301 of the second liquid cooling plate 32 from the circulation flow path 301 of the first liquid cooling plate 31 through the communication flow path 302 by the communication flow path 302 of the connection pipe 34.

Example III

The present embodiment is similar to the first embodiment, and differs only in the internal structure of the second liquid cooling plate 32.

As shown in fig. 9, the liquid cooling assembly 30 provided in this embodiment further includes a partition 35, the partition 35 is disposed in the circulation flow channel 301 of the second liquid cooling plate 32, the partition 35 is disposed along the extending direction of the circulation flow channel 301 of the second liquid cooling plate 32, the partition 35 separates the circulation flow channel 301 of the second liquid cooling plate 32 into two sub-flow channels 3011, so as to facilitate the flow of the cooling liquid, and the two sub-flow channels 3011 are respectively connected to the second side walls of the two battery modules 20 in a heat conduction manner.

The second liquid cooling plate 32 adopts a double-sided cooling mode, so that two battery modules 20 positioned on two sides of the second liquid cooling plate 32 along the W direction can be cooled through two sub-channels 3011 simultaneously, the heat exchange area is increased, each battery module 20 can be cooled by one side surface independently, and the heat dissipation effect is good.

It should be noted that the number of the partition 35 and the sub-flow paths 3011 may be adjusted according to the pressure difference and the heat exchange condition.

It should be noted herein that the liquid cooling assembly shown in the drawings and described in this specification is merely one example of the principles of the present invention. It will be clearly understood by those of ordinary skill in the art that the principles of the present invention are not limited to any details or any components of the devices shown in the drawings or described in the specification.

It should be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the specification. The invention is capable of other embodiments and of being practiced and carried out in various ways. The foregoing variations and modifications are intended to fall within the scope of the present invention. It should be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described in this specification illustrate the best mode known for carrying out the invention and will enable those skilled in the art to make and use the invention.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. The specification and example embodiments are to be considered exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (12)

1. An energy storage device, comprising:

a battery module (20);

a first liquid cooling plate (31) which is in heat conduction connection with a first side wall of the battery module (20) along the height direction of the battery module (20);

the second liquid cooling plate (32) is vertically arranged on the first liquid cooling plate (31), the second liquid cooling plate is in contact with the second side wall of the battery module (20), circulating flow channels (301) are arranged in the first liquid cooling plate (31) and the second liquid cooling plate (32), and the circulating flow channels (301) of the first liquid cooling plate (31) and the circulating flow channels (301) of the second liquid cooling plate (32) are communicated;

the first side wall is perpendicular to the second side wall, the first liquid cooling plate (31) is provided with a plurality of liquid cooling areas (311), the circulating flow channels (301) corresponding to the liquid cooling areas (311) are arranged in parallel, and the flow channel length of at least one circulating flow channel (301) corresponding to at least one liquid cooling area in the liquid cooling areas (311) is smaller than the flow channel lengths of other circulating flow channels (301) corresponding to other liquid cooling areas (311).

2. The energy storage device according to claim 1, wherein the projection areas of the plurality of liquid cooling areas (311) on the first liquid cooling plate along the height direction of the battery module (20) are different.

3. The energy storage device according to claim 2, wherein the circulation flow path (301) of the first liquid cooling plate (31) and the circulation flow path (301) of the second liquid cooling plate (32) are communicated through a communication flow path (302), and the flow path lengths of the circulation flow paths (301) of the plurality of liquid cooling regions (311) gradually decrease in a direction approaching the communication flow path (302);

and/or the circulating flow channels (301) of the first liquid cooling plate (31) and the circulating flow channels (301) of the second liquid cooling plate (32) are communicated through a communication flow channel (302), and the flow channel sectional areas of the circulating flow channels (301) of the plurality of liquid cooling areas (311) gradually decrease along the direction approaching to the communication flow channel (302).

4. The energy storage device according to claim 1, wherein the first liquid cooling plate (31) is provided with a liquid inlet flow channel (303), the second liquid cooling plate (32) is provided with a liquid outlet flow channel (304), and the liquid inlet flow channel (303), the circulating flow channel (301) of the first liquid cooling plate (31), the circulating flow channel (301) of the second liquid cooling plate (32) and the liquid outlet flow channel (304) are communicated;

The liquid inlet flow channel (303) and the liquid outlet flow channel (304) are positioned on the same side of the first liquid cooling plate (31) along the length direction of the first liquid cooling plate (31); and/or the liquid inlet flow channel (303) and the liquid outlet flow channel (304) are positioned on the same side of the first liquid cooling plate (31) along the width direction of the first liquid cooling plate (31).

5. The energy storage device according to claim 4, wherein the circulating flow channels (301) corresponding to the liquid cooling areas (311) have different flow channel cross sections near one end of the liquid inlet flow channel (303).

6. The energy storage device according to claim 4, wherein the circulation flow channel (301) corresponding to each liquid cooling zone (311) comprises a plurality of cooling units (312) arranged in series;

the liquid inlet flow channel (303) is communicated with the cooling unit (312) close to the liquid inlet flow channel (303) through a main channel (313), and the extending directions of the main channel (313) and the liquid inlet flow channel (303) are different.

7. The energy storage device according to claim 6, characterized in that the cooling unit (312) comprises a plurality of cooling branches (3120) arranged in parallel;

the cooling branch (3120) is arranged to extend along the length direction of the first liquid cooling plate (31); or, the cooling branch (3120) is extended along the width direction of the first liquid cooling plate (31).

8. The energy storage device according to claim 6, wherein the circulation flow channel (301) of the first liquid cooling plate (31) is in communication with the circulation flow channel (301) of the second liquid cooling plate (32) through a communication flow channel (302);

adjacent two cooling units (312) are communicated through a cooling main path (315), and turbulence pieces (314) are arranged in the cooling units (312) and/or the cooling main path (315);

the first liquid cooling plate (31) is provided with the turbulence piece (314) at one side close to the communication flow passage (302).

9. The energy storage device of claim 1, further comprising:

a support member (33), wherein one end of the support member (33) in the height direction of the battery module (20) is connected to the first liquid cooling plate (31), and the other end is connected to the second liquid cooling plate (32);

the first liquid cooling plate (31), the second liquid cooling plate (32) and the supporting piece (33) are of an integrated structure.

10. The energy storage device of claim 1, further comprising:

the support piece (33), one end of the support piece (33) along the height direction of the battery module (20) is connected to the first liquid cooling plate (31), one of the other end of the support piece (33) along the height direction of the battery module (20) and the second liquid cooling plate (32) is provided with a positioning column (316), the other end of the support piece is provided with a positioning hole (331), and the positioning column (316) penetrates through the positioning hole (331);

The connecting pipeline (34) is located between the first liquid cooling plate (31) and the second liquid cooling plate (32), the connecting pipeline (34) is detachably connected with the first liquid cooling plate (31) and the second liquid cooling plate (32) respectively, a communication runner (302) is arranged in the connecting pipeline (34), and the circulating runner (301) of the first liquid cooling plate (31) is communicated with the circulating runner (301) of the second liquid cooling plate (32) through the communication runner (302).

11. The energy storage device according to any one of claims 1-10, further comprising a separator (35), wherein the separator (35) is disposed in the circulation flow channel (301) of the second liquid cooling plate (32), the separator (35) is disposed along an extending direction of the circulation flow channel (301) of the second liquid cooling plate (32), the separator (35) separates the circulation flow channel (301) of the second liquid cooling plate (32) into two sub flow channels (3011), and the two sub flow channels (3011) are respectively connected to the second side walls of the two battery modules (20) in a heat conduction manner.

12. An energy storage system comprising a powered device (300) and an energy storage device according to any of claims 1-11, the energy storage device powering the powered device (300).