Submerged energy storage device, energy storage system and control method thereof

Abstract

The embodiment of the application relates to the technical field of energy storage, and provides an immersed energy storage device, an energy storage system and a control method thereof, the immersed energy storage device comprising: a box body; a battery module comprising a plurality of battery cells, located in the box body, and having a gap between adjacent two battery cells; a liquid cooling structure comprising a bottom plate, located in the box body, the bottom plate being located at the bottom of the battery module, the bottom plate being provided with a flow guide cavity and a liquid inlet, the flow guide cavity being in communication with the gap and the liquid inlet respectively; a liquid storage pool for storing refrigerant, an outlet of the liquid storage pool being in communication with the liquid inlet of the bottom plate, the refrigerant flowing into the flow guide cavity and the gap through the liquid inlet of the bottom plate; a refrigerator comprising a cold end and a hot end, the cold end being located at one side of an opening of the liquid storage pool in the box body, and the hot end being located outside the box body; and a heat dissipation fan located outside the box body, an air outlet direction of the heat dissipation fan corresponding to the hot end. The immersed energy storage device provided by the embodiment of the application can at least improve the problem of uneven heat dissipation of battery cells at different positions in a battery cabinet in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to an immersed energy storage device, an energy storage system and a control method thereof. BACKGROUND

[0002] The energy storage system is provided with battery cells. Heat is generated during the charging and discharging process of the battery cells, which causes the temperature of the battery cells to rise. If the temperature of the battery cells is not controlled, the efficiency and service life of the battery cells may be reduced or the battery cells may be out of control. The natural heat dissipation of the battery cells cannot maintain the temperature within the working range, and therefore a cooling system must be configured.

[0003] The current liquid cooling system has the problem of uneven heat dissipation of battery cells at different positions in the battery cabinet due to the layout and structure of the flow channel. SUMMARY

[0004] The embodiments of the present application provide an immersed energy storage device, an energy storage system and a control method thereof, which at least help to improve the problem of uneven heat dissipation of battery cells at different positions in the battery cabinet in the prior art.

[0005] According to some embodiments of the present application, the embodiments of the present application provide an immersed energy storage device, comprising: a box body; a battery module located in the box body, the battery module comprising a plurality of battery cells, and a gap being provided between two adjacent battery cells; a liquid cooling structure located in the box body, the liquid cooling structure comprising a bottom plate, the bottom plate being located at the bottom of the battery module, the bottom plate being provided with a flow guide cavity and a liquid inlet, the flow guide cavity being in communication with the gap and the liquid inlet respectively; a liquid storage pool located at one side of the liquid cooling structure in the box body, the liquid storage pool being used for storing a refrigerant, a liquid outlet of the liquid storage pool being in communication with the liquid inlet of the bottom plate, and the refrigerant flowing into the flow guide cavity and the gap through the liquid inlet of the bottom plate; a refrigerator comprising a cold end and a hot end, the cold end being located at one side of an opening of the liquid storage pool in the box body, and the hot end being located outside the box body; and a heat dissipation fan located outside the box body and facing the hot end.

[0006] In some embodiments, the box body has opposite bottom and top surfaces, the liquid storage pool is located on the bottom surface, the cold end is located on the top surface, and the surface of the cold end has a first position and a second position arranged in sequence in a direction of the liquid cooling structure pointing to the liquid storage pool, the distance from the first position to the liquid storage pool being greater than the distance from the second position to the liquid storage pool.

[0007] In some embodiments, the liquid level of the refrigerant in the sump and the gap is leveled, a liquid supplement port is arranged on the box, one end of the liquid supplement port communicates with the sump, the immersion energy storage device further comprises: a standby liquid storage structure for storing the refrigerant, the standby liquid storage structure is located outside the box and communicates with the other end of the liquid supplement port; and an electromagnetic valve is arranged on the communication pipeline between the liquid supplement port and the standby liquid storage structure.

[0008] In some embodiments, before the electromagnetic valve is opened, the liquid level of the refrigerant in the sump is 1 / 2-2 / 3 of the depth of the sump.

[0009] In some embodiments, the immersion energy storage device further comprises: an electric heater arranged in the sump; a liquid guide pipe and a circulating pump, both of which are arranged in the box between the sump and the liquid cooling structure, one end of the liquid guide pipe communicates with the flow guide cavity, one end of the circulating pump communicates with one end of the liquid guide pipe, the other end of the circulating pump communicates with the liquid inlet of the bottom plate, and the circulating pump is used to make the refrigerant circulate in the bottom plate and the liquid guide pipe.

[0010] In some embodiments, the refrigerant comprises R134a refrigerant, and the immersion energy storage device further comprises: a constant pressure controller communicating with the box and used to control the pressure in the box to be kept at 4.5-5.5 bar.

[0011] In some embodiments, the bottom plate comprises a flow channel part extending along a first direction and a support part, two support parts are located on both sides of the flow channel part along a second direction, the flow guide cavity is located between the flow channel part and the support part, one end of the flow channel part close to the sump communicates with the liquid inlet of the bottom plate, and the other end of the flow channel part away from the sump communicates with the flow guide cavity, and the first direction intersects the second direction.

[0012] In some embodiments, the liquid cooling structure further comprises two side plates oppositely arranged along the first direction, and the two side plates are respectively connected with the bottom plate, and the battery module is located between and respectively contacts with the two side plates.

[0013] In some embodiments, a plurality of the battery cells are arranged at intervals along the first direction, two isolation pieces are arranged at intervals in the second direction between two adjacent battery cells, the two isolation pieces make the gap between the two adjacent battery cells and close the gap in the second direction, the gap overlaps with the flow guide cavity in a third direction, the bottom edge of the battery cell in the first direction contacts with the support part, and the third direction is the arrangement direction of the sump and the cold end.

[0014] According to some embodiments of the present application, another aspect of the embodiments of the present application provides an energy storage system, comprising any of the immersion energy storage devices.

[0015] According to some embodiments of the present application, another aspect of the embodiments of the present application provides a control method of an energy storage system, the control method of the energy storage system comprising: obtaining an ambient temperature; and controlling a switching state of a refrigerator and a cooling fan according to at least the ambient temperature, to perform thermal management on a battery module.

[0016] In some embodiments, the step of controlling the switching state of the refrigerator and the cooling fan according to at least the ambient temperature comprises: in a case where the ambient temperature is greater than a first threshold value and less than or equal to a second threshold value, controlling the refrigerator and the cooling fan to be in an off state; and in a case where the ambient temperature is greater than the second threshold value, controlling the refrigerator and the cooling fan to be in an on state, and controlling a current flowing into the refrigerator according to the ambient temperature, so that a hot end temperature of the controlled refrigerator is greater than the ambient temperature.

[0017] In some embodiments, the step of controlling the current flowing into the refrigerator according to the ambient temperature comprises: in a case where the ambient temperature is greater than the second threshold value and less than or equal to a third threshold value, controlling the refrigerator and the cooling fan to be in the on state, and flowing a first current into the refrigerator; in a case where the ambient temperature is greater than the third threshold value and less than or equal to a fourth threshold value, controlling the refrigerator and the cooling fan to be in the on state, and flowing a second current into the refrigerator; and in a case where the ambient temperature is greater than the fourth threshold value and less than a fifth threshold value, controlling the refrigerator and the cooling fan to be in the on state, and flowing a third current into the refrigerator, the first current, the second current, and the third current increasing in turn.

[0018] In some embodiments, the immersion energy storage device further comprises an electric heater located in the liquid pool, and the control method of the energy storage system further comprises: in a case where the ambient temperature is less than or equal to the first threshold value, controlling the electric heater to be turned on to heat the refrigerant in the liquid pool, and controlling the refrigerator and the cooling fan to remain in the off state.

[0019] In some embodiments, the box comprises a liquid supplement port, one end of the liquid supplement port being in communication with the liquid pool, the immersion energy storage device further comprising: a standby liquid storage structure for storing the refrigerant, the standby liquid storage structure being located outside the box and in communication with the other end of the liquid supplement port; an electromagnetic valve located on the communication pipeline between the liquid supplement port and the standby liquid storage structure; a liquid guide pipe and a circulating pump, both located between the liquid pool and the liquid cooling structure in the box, one end of the liquid guide pipe being in communication with the flow guide cavity, one end of the circulating pump being in communication with one end of the liquid guide pipe, the other end of the circulating pump being in communication with the liquid inlet of the bottom plate, and the control method of the energy storage system further comprising: acquiring the temperature of the battery module; in the case that the temperature of the battery module is greater than a sixth threshold value and less than or equal to a seventh threshold value, controlling the electromagnetic valve to be in an open state and controlling the circulating pump to be in a closed state to inject the refrigerant from the standby liquid storage structure into the liquid pool, so that the liquid level in the liquid pool rises to a predetermined liquid level value; in the case that the temperature of the battery module is greater than the seventh threshold value, controlling the circulating pump to be in an open state, so that the refrigerant circulates in the bottom plate and the liquid guide pipe to cool the battery module.

[0020] The technical scheme provided by the embodiments of the present application has at least the following advantages: in the immersion energy storage device of the present application, the refrigerant in the liquid pool flows into the gap of the battery cell through the liquid inlet of the liquid cooling structure bottom plate and the flow guide cavity, realizes immersion of the battery cell, ensures that the refrigerant can be uniformly distributed around the battery cell, and adopts immersion cooling, the refrigerant directly contacts the surface of the battery cell, absorbs heat by evaporation, and carries away the heat generated by the battery cell during charging and discharging, the cooling method of direct contact can effectively absorb and conduct heat, the cold end of the refrigerator is located in the box close to the opening of the liquid pool, and the hot end is exposed outside the box and cooled by a cooling fan, when the temperature of the battery cell rises, the refrigerant evaporates and absorbs heat to become gaseous refrigerant, and then flows through the cold end of the refrigerator and is quickly condensed, the released heat is transmitted to the external environment through the hot end, this design not only improves the heat dissipation efficiency, but also realizes the recycling of the refrigerant, reduces the temperature rise of the cooling liquid in the flow direction, and ensures that each battery cell can be effectively cooled, ensures that the cooling effect of multiple battery cells is relatively uniform, ensures that the heat dissipation of multiple battery cells is relatively uniform, ensures the uniformity and stability of the battery temperature, and further improves the performance and service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which should not be taken as limiting the embodiments, unless specified otherwise in the claims. The drawing figures are not necessarily drawn to scale, except as otherwise noted in the conditions of the figures. In order to more clearly illustrate the technical solutions in the embodiments or in the prior art, the figures needed in the embodiments will be briefly introduced as follows. Obviously, the figures in the following description only constitute some embodiments of the present application, and for those skilled in the art, other figures can be obtained from these figures without creative effort.

[0022] Figure 1 A structural schematic diagram of an immersed energy storage device provided by an embodiment of the present application;

[0023] Figure 2 A front view of the immersed energy storage device in the energy storage system provided by an embodiment of the present application; Figure 1

[0024] Figure 3 A bottom view of the immersed energy storage device in the energy storage system provided by an embodiment of the present application; Figure 1

[0025] Figure 4 A structural schematic diagram of a partition in the immersed energy storage device in the energy storage system provided by an embodiment of the present application; Figure 1

[0026] Figure 5 A top view of the partition in the immersed energy storage device in the energy storage system provided by an embodiment of the present application. Figure 4 The figures are marked as follows:

[0027]

[0028] 11, box body; 12, battery module; 121, battery cell; 122, gap; 13, liquid cooling structure; 14, bottom plate; 141, flow guide cavity; 142, liquid inlet; 143, flow channel part; 144, support part; 15, liquid storage pool; 151, liquid outlet; 16, refrigerator; 161, cold end; 162, hot end; 17, heat dissipation fan; 18, liquid supplementing port; 19, liquid guide pipe; 20, circulating pump; 21, side plate; 22, partition; 23, steel belt. DETAILED DESCRIPTION

[0029] As known from the background, the battery cells at different positions in the battery cabinet are not evenly cooled in the prior art. To solve the above technical problem, the present application provides an immersed energy storage device, an energy storage system and a control method thereof.

[0030] ​​​​In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise explicitly specified and limited.

[0031] Reference herein to "embodiments" means that the particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily a separate or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean: A exists, A and B exist, and B exists. In addition, the character " / " herein generally represents an "or" relationship between the preceding and following associated objects.

[0033] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0034] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0035] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the terms in the embodiments of the present application can be understood according to the specific circumstances.

[0036] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0037] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0038] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0039] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0040] This application provides an embodiment of an immersion energy storage device, such as... Figures 1 to 5 As shown, it includes:

[0041] Box 11;

[0042] The battery module 12 is located in the housing 11. The battery module 12 includes a plurality of battery cells 121, and there is a gap 122 between two adjacent battery cells 121.

[0043] A liquid cooling structure 13 is located in the box 11, and the liquid cooling structure 13 comprises a bottom plate 14 located at the bottom of the battery module 12, wherein the bottom plate 14 is provided with a flow guide cavity 141 and a liquid inlet 142, and the flow guide cavity 141 is in communication with the gap 122 and the liquid inlet 142, respectively.

[0044] A liquid storage pool 15 is located at one side of the liquid cooling structure 13 in the box 11, and is used for storing refrigerant (not shown), wherein the liquid outlet 151 of the liquid storage pool 15 is in communication with the liquid inlet 142 of the bottom plate 14, and the refrigerant flows into the flow guide cavity 141 and the gap 122 through the liquid inlet 142 of the bottom plate 14.

[0045] A refrigerator 16 comprises a cold end 161 and a hot end 162, wherein the cold end 161 is located at the opening side of the liquid storage pool 15 in the box 11, and the hot end 162 is located outside the box 11.

[0046] A heat dissipation fan 17 is located outside the box 11, and the heat dissipation fan 17 blows air towards the hot end 162.

[0047] According to the embodiment, in the immersion type energy storage device, the refrigerant in the liquid storage pool flows into the gap of the battery cell through the liquid inlet of the bottom plate of the liquid cooling structure, so as to realize immersion of the battery cell, and ensure that the refrigerant can be uniformly distributed around the battery cell. In addition, the immersion type cooling is adopted, the refrigerant directly contacts the surface of the battery cell, and the heat generated by the battery cell in the charging and discharging process is taken away by the evaporation and heat absorption of the refrigerant. The direct contact cooling method can effectively absorb and conduct heat. The cold end of the refrigerator is located at the opening side of the liquid storage pool in the box, and the hot end is exposed outside the box. The heat dissipation fan is used for cooling. When the temperature of the battery cell rises, the refrigerant is evaporated and absorbs heat to become gaseous refrigerant, and then flows through the cold end of the refrigerator and is rapidly condensed. The heat released by the refrigerant is transmitted to the external environment through the hot end. The design not only improves the heat dissipation efficiency, but also realizes the recycling of the refrigerant, reduces the temperature rise of the cooling liquid in the flow direction, and ensures that each battery cell can be effectively cooled, so as to ensure that the cooling effect of multiple battery cells is relatively uniform, so as to ensure that the heat dissipation of multiple battery cells is relatively uniform, and the uniformity and stability of the battery temperature are ensured, and the performance and service life of the battery are improved.

[0048] Specifically, the hot end of the refrigerator is located outside the box, and is cooled by the environment and the heat dissipation fan.

[0049] In other embodiments, the hot end of the cooler may be provided with fins. The fins increase the contact area between the hot end and the outside air, so that the hot end can more effectively dissipate the heat conducted from the cold end into the environment. The fin design can accelerate heat transfer, especially in air-cooled systems, where the forced convection of the cooling fan allows air to flow through the fins faster, thereby improving the heat dissipation speed of the hot end.

[0050] It should be noted that the gas temperature above the battery cell module is higher and expands in volume, while the temperature above the liquid storage tank is lower. Therefore, the gas inside the tank will form a natural flow, and the superheated vapor will spontaneously flow to the cold end of the cooler and be condensed. The condensed refrigerant then returns to the liquid storage tank.

[0051] In one alternative, such as Figure 1 and Figure 2 As shown, the housing 11 has opposing bottom and top surfaces. The liquid storage tank 15 is located on the bottom surface, and the cold end 161 is located on the top surface. The surface of the cold end 161 has a first position and a second position arranged sequentially along the direction from the liquid cooling structure 13 towards the liquid storage tank 15. The distance from the first position to the liquid storage tank 15 is greater than the distance from the second position to the liquid storage tank 15. The surface of the cold end is inclined. Through this inclined design, the condensed liquid can more easily slide back to the liquid storage tank along the inclined surface using gravity, reducing the retention of droplets on the surface of the cold end, thereby reducing droplet evaporation loss and improving the refrigerant circulation efficiency.

[0052] Furthermore, such as Figure 1 and Figure 2 As shown, the surface of the cold end 161 is an inclined surface, meaning that the distance from the surface of the cold end 161 to the liquid storage tank 15 gradually decreases along the direction from the liquid cooling structure 13 to the liquid storage tank 15. In this embodiment, the distance between the cold end and the liquid storage tank is designed to gradually decrease along the direction from the liquid cooling structure to the liquid storage tank.

[0053] According to some exemplary embodiments of this application, such as Figure 1 and Figure 2As shown, the liquid level of the refrigerant in the sump 15 and the gap 122 is the same, that is, the liquid level of the refrigerant in the sump 15 is the same as the liquid level of the refrigerant in the gap 122, and the tank 11 is provided with a liquid supplement port 18, one end of the liquid supplement port 18 being in communication with the sump 15, and the immersion energy storage device further comprises: a standby liquid storage structure (not shown) for storing the refrigerant, the standby liquid storage structure being located outside the tank 11 and being in communication with the other end of the liquid supplement port 18; and an electromagnetic valve (not shown) located on the communication pipeline between the liquid supplement port 18 and the standby liquid storage structure. In this embodiment, the principle of communicating vessels is used to keep the liquid levels of the refrigerant in the sump and the gap between the battery cells balanced, thereby avoiding uneven cooling caused by the difference in liquid levels; the liquid supplement port provided on the tank is connected to the standby liquid storage structure outside the tank, and can automatically supplement the refrigerant when the refrigerant is reduced due to evaporation, thereby maintaining a constant liquid level and avoiding a decrease in cooling effect caused by a decrease in the liquid level; and the electromagnetic valve is provided to enable the liquid supplement process to be accurately controlled, thereby preventing excessive refrigerant from flowing into the battery pack, which not only helps to maintain a stable working environment inside the battery pack, but also increases the safety of the system and avoids potential risks caused by refrigerant leakage or excessive refrigerant.

[0054] Specifically, the liquid supplement port is controlled by the electromagnetic valve, and refrigerant liquid can be flexibly supplemented or pumped out of the sump according to the operating state of the battery.

[0055] According to some example embodiments of the present application, the liquid level of the refrigerant in the sump before the electromagnetic valve is opened is 1 / 2 to 2 / 3 of the depth of the sump. In this embodiment, by controlling the liquid level of the refrigerant before the electromagnetic valve is opened, it is ensured that there is enough refrigerant for circulation when the cooling system is started, and reasonable liquid level control avoids insufficient or excessive refrigerant, which affects the cooling effect and the stability of the system.

[0056] In other embodiments, as shown in Figure 1 and Figure 2 The immersion energy storage device further comprises: an electric heater (not shown) located in the sump 15; a liquid guide pipe 19 and a circulating pump 20, both of which are located between the sump 15 and the liquid cooling structure 13 in the tank 11, one end of the liquid guide pipe 19 being in communication with the flow guide cavity 141, one end of the circulating pump 20 being in communication with one end of the liquid guide pipe 19, and the other end of the circulating pump 20 being in communication with the liquid inlet 142 of the bottom plate 14, the circulating pump 20 being used to make the refrigerant circulate in the bottom plate 14 and the liquid guide pipe 19. In this embodiment, the refrigerant is driven to circulate between the battery pack and the sump by the circulating pump, which can more effectively balance the temperature in the battery pack, the refrigerant can be forced to flow, and uneven heat dissipation caused by natural convection can be reduced, and the electric heater can heat the refrigerant in a low-temperature environment to avoid freezing of the refrigerant.

[0057] Specifically, a circulating pump is added, and a corresponding flow channel is designed, so that the liquid in the flow channel can flow by itself, and the bottom of the battery cell can be fully cooled.

[0058] According to some example embodiments of the present application, the refrigerant includes R134a refrigerant, and the immersion energy storage device further includes a constant pressure controller in communication with the tank and configured to control the pressure in the tank to be kept at 4.5-5.5 bar. In this embodiment, by using R134a as the refrigerant, the heat generated during the charging and discharging of the battery pack can be effectively absorbed by using the evaporation characteristics of R134a at a specific pressure. The evaporation temperature of R134a can be controlled in a relatively ideal range within the pressure range of 4.5-5.5 bar, so that the heat can be effectively absorbed even when the battery temperature is relatively high, thereby achieving efficient heat dissipation of the battery pack.

[0059] Specifically, for example, the constant pressure controller can ensure that the pressure in the battery pack is kept at 5 bar, and the evaporation temperature of the R134a refrigerant is 15℃. When the R134a evaporates, it will absorb heat, and when it flows out from the gap between the battery cells in the form of steam, it will also absorb part of the heat of the battery cells because the steam temperature is lower than the temperature of the upper surface of the battery cells, and it will become superheated steam, thereby achieving twice heat dissipation.

[0060] For example, the constant pressure controller monitors the pressure in the tank. When the pressure in the tank is greater than 5.5 bar, the constant pressure controller increases the exhaust by opening or opening the exhaust valve, or reduces the intake by closing or closing the intake valve. When the pressure in the tank is less than 4.5 bar, the constant pressure controller increases the intake by controlling the opening or opening of the intake valve, or reduces the exhaust by closing or closing the exhaust valve.

[0061] According to some example embodiments of the present application, the refrigerant includes R134a refrigerant, and the immersion energy storage device further includes a constant pressure controller in communication with the tank and configured to control the pressure in the tank to be kept at 4.5-5.5 bar. In this embodiment, by using R134a as the refrigerant, the heat generated during the charging and discharging of the battery pack can be effectively absorbed by using the evaporation characteristics of R134a at a specific pressure. The evaporation temperature of R134a can be controlled in a relatively ideal range within the pressure range of 4.5-5.5 bar, so that the heat can be effectively absorbed even when the battery temperature is relatively high, thereby achieving efficient heat dissipation of the battery pack. Figure 3 As shown in FIG. 14, the bottom plate 14 includes a flow channel portion 143 extending in a first direction and a support portion 144, two support portions 144 are located on both sides of the flow channel portion 143 along a second direction, the flow guide cavity 141 is located between the flow channel portion 143 and the support portion 144, one end of the flow channel portion 143 close to the liquid pool 15 is in communication with the liquid inlet 142 of the bottom plate 14, and the other end of the flow channel portion 143 away from the liquid pool 15 is in communication with the flow guide cavity 141, and the first direction intersects the second direction. In this embodiment, the design of the support portion enhances the structural strength of the bottom plate, prevents deformation caused by uneven stress for a long time, and the two support portions are respectively located on both sides of the flow channel portion. They not only support the battery cells, but also cooperate with the flow guide cavity to form a stable flow channel network. By designing the flow channel portion and the support portion of the bottom plate, the flow path of the refrigerant is optimized, and the cooling efficiency is further improved.

[0062] In some optional solutions of the present application, as shown in Figure 1 and Figure 2 The liquid cooling structure 13 further comprises two side plates 21 arranged oppositely along the first direction, and each of the two side plates 21 is connected with the bottom plate 14. The battery module 12 is located between the two side plates 21 and contacts with the two side plates 21 respectively. In this embodiment, the connection between the side plate and the bottom plate enhances the structural rigidity of the whole battery pack, which helps to prevent the deformation or damage of the battery module caused by external impact during transportation or use, and improves the safety of the system.

[0063] In some optional solutions of the present application, as shown in Figures 3 to 5 The plurality of battery cells 121 are arranged at intervals along the first direction. Two isolation pieces 22 are arranged at intervals in the second direction between two adjacent battery cells 121. The two isolation pieces 22 make the two adjacent battery cells 121 have the gap 122 and close the gap 122 in the second direction. The gap 122 overlaps with the flow guide cavity 141 in the third direction. The bottom edge of the battery cell 121 in the first direction contacts with the support part 144. The third direction is the arrangement direction of the liquid pool 15 and the cold end (not shown). In this embodiment, the design of the two isolation pieces ensures that the flow of the refrigerant in the second direction is limited and can only flow through the preset gap and the flow guide cavity. By arranging the isolation pieces between the battery cells, an effective flow path is formed. The refrigerant can directly absorb heat at the position where the bottom edge of the battery cell contacts with the support part, i.e., the position where the heat source of the battery cell is most concentrated, and then evaporate and rise, thereby improving the heat exchange efficiency and effectively reducing the temperature of the battery cell. By arranging the gap and the flow guide cavity in the third direction (i.e., the arrangement direction of the liquid pool and the cold end), it is ensured that the refrigerant can directly flow to the cold end for condensation after evaporation, which reduces the ineffective circulation of the refrigerant in the system and improves the use efficiency of the refrigerant.

[0064] Specifically, since there is a gap between two adjacent battery cells, the isolation piece acts as a partition to limit the flow of the refrigerant in the second direction, so that the refrigerant can only flow in the preset gap and the flow guide cavity, avoiding the outflow of the refrigerant.

[0065] Specifically, Figure 3 In this embodiment, the dashed line with an arrow represents the flow path of the refrigerant.

[0066] Specifically, as shown in Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the plurality of battery cells 121 in the battery module 12 and the side plate 21 can be fixed by the steel belt 23, and the battery cells 121 are sealed by the spacer 22 on the outer side gap. In addition to the outer side gap, other gaps can be used for refrigerant circulation.

[0067] In summary, the immersion energy storage device (i.e., using the immersion evaporation cooling + refrigerator mode to cool the battery module) of the present application has better immersion evaporation cooling effect than conventional liquid cooling heat exchange, and can absorb more heat. The immersion evaporation cooling + refrigerator uses a PACK-level independent liquid cooling system to solve the problem of uneven cooling between PACKs caused by the liquid cooling plate cooling mode. By controlling the pressure in the box, the evaporation temperature of the refrigerant is lower than the upper surface temperature of the battery cell. The refrigerant can not only absorb heat through evaporation, but also further heat the upper surface of the battery cell during evaporation, which can heat the upper and lower parts of the battery cell, and ensure good heat dissipation effect of the battery cell, and improve the battery performance and life.

[0068] The embodiment of the present application also provides a kind of energy storage system, comprising: any one of the immersion energy storage device.

[0069] The embodiment of the present application also provides a kind of energy storage system control method, the energy storage system control method comprises:

[0070] Step S101, obtain the ambient temperature;

[0071] Step S102, at least according to the ambient temperature, control the switch state of the refrigerator and the cooling fan, to carry out thermal management to the battery module.

[0072] Through the embodiment, through the real-time monitoring of ambient temperature, according to the height of ambient temperature, the working state of refrigerator and cooling fan is adjusted, it is ensured that battery module works in suitable temperature range, and system can automatically adjust refrigeration power and air cooling efficiency according to actual demand, without manual intervention, improve the automation level and response speed of system.

[0073] In an alternative, the switching state of the cooler and the heat dissipation fan is controlled according to at least the ambient temperature, including: when the ambient temperature is greater than a first threshold value and less than or equal to a second threshold value, the cooler and the heat dissipation fan are controlled to be in an off state; when the ambient temperature is greater than the second threshold value, the cooler and the heat dissipation fan are controlled to be in an on state, and the current flowing into the cooler is controlled according to the ambient temperature, so that the hot end temperature of the controlled cooler is greater than the ambient temperature. In this embodiment, the operating state of the heat dissipation system is automatically adjusted based on the ambient temperature. When the ambient temperature is in a suitable range (greater than the first threshold value but not more than the second threshold value), the system automatically turns off the cooler and the heat dissipation fan to reduce unnecessary energy consumption and improve the energy utilization efficiency of the system. When the ambient temperature rises above the second threshold value, the system automatically starts the heat dissipation measures to ensure that the temperature of the battery pack is maintained within a safe and efficient operating range. By dynamically adjusting the current flowing into the cooler according to the ambient temperature, the hot end temperature of the cooler can be accurately controlled to be always higher than the ambient temperature, which not only ensures that the cooler can work effectively at any ambient temperature, but also avoids excessive cooling in a low-temperature environment, thereby protecting the battery pack from cold damage and prolonging the battery life.

[0074] In actual application, the first threshold value and the second threshold value can be set according to experience values or obtained through multiple experiments, which are not limited in the present application. In the embodiment of the present application, the first threshold value is 0°C, and the second threshold value is 10°C.

[0075] According to some example embodiments of the present application, the current flowing into the cooler is controlled according to the ambient temperature, including: when the ambient temperature is greater than the second threshold value and less than or equal to a third threshold value, the cooler and the heat dissipation fan are controlled to be in an on state, and a first current is supplied to the cooler; when the ambient temperature is greater than the third threshold value and less than or equal to a fourth threshold value, the cooler and the heat dissipation fan are controlled to be in an on state, and a second current is supplied to the cooler; when the ambient temperature is greater than the fourth threshold value and less than a fifth threshold value, the cooler and the heat dissipation fan are controlled to be in an on state, and a third current is supplied to the cooler, and the first current, the second current and the third current increase in turn. In this embodiment, different current threshold values are set corresponding to different ambient temperatures, so that the cooling system can flexibly respond to changes in ambient temperature, ensuring that the battery pack can be effectively cooled in a wide temperature range and avoiding overheating or insufficient heat dissipation of the battery due to fluctuations in ambient temperature. The operating current of the cooler is set in a stepped manner according to the ambient temperature, ensuring that the ambient temperature is sufficiently lower than the hot end temperature while ensuring that the operating power consumption of the cooler is small.

[0076] In actual application, the third threshold, the fourth threshold, the fifth threshold, the first current, the second current and the third current can be set according to experience values, or can be obtained through multiple experiments, which are not specifically limited in the application. In the embodiment of the application, the third threshold is 25℃, the fourth threshold is 30℃, the fifth threshold is 45℃, the first current is 1.6A, the second current is 2.4A, and the third current is 4A.

[0077] For example, a current of 4A is input to the refrigerator, the cold end temperature is controlled to be 3-4℃, and the hot end temperature is controlled to be 48℃. Since the hot end temperature is higher than the ambient temperature, it is ensured that the external environment can cool the hot end of the refrigerator. When the ambient temperature is relatively high, the current can be increased, so that the hot end has a higher temperature.

[0078] According to some example embodiments of the application, the immersion energy storage device further comprises an electric heater located in the liquid pool, and the control method of the energy storage system further comprises: in the case that the ambient temperature is less than or equal to the first threshold, controlling the electric heater to be turned on to heat the refrigerant in the liquid pool, and controlling the refrigerator and the cooling fan to be kept in the closed state. In this embodiment, when the ambient temperature is lower than the set first threshold, the system automatically enables the electric heater to heat the refrigerant in the liquid pool. This way can ensure that the refrigerant remains in a suitable working state in a low-temperature environment, avoiding problems such as performance degradation of the refrigerant or failure of the system to start normally due to too low temperature. In a low-temperature environment, only the electric heater is turned on, while the refrigerator and the cooling fan are turned off. This design avoids unnecessary energy consumption of the refrigerator and the cooling fan in a low-temperature condition without the need for refrigeration, thereby improving the energy efficiency of the entire system.

[0079] Specifically, the ambient temperature Te is monitored: when the ambient temperature Te is less than 0℃, the electric heater is turned on, and the refrigerator, the circulating pump and the cooling fan are all in the closed state; when the ambient temperature Te is greater than 0℃ and less than 10℃, the electric heater, the refrigerator and the cooling fan are all in the closed state, and natural wind is used to cool the fins of the refrigerator, which can fully utilize the natural cold source, reduce the running time of the refrigerator and reduce the power consumption; when the ambient temperature Te is greater than 10℃ and less than 25℃, the refrigerator and the cooling fan are turned on, and a current of 1.6A is input to the refrigerator, so that the hot end temperature reaches about 34℃; when the ambient temperature Te is greater than 25℃ and less than 30℃, the refrigerator and the cooling fan are turned on, and a current of 2.4A is input to the refrigerator, so that the hot end temperature reaches about 42℃; when the ambient temperature Te is greater than 30℃ and less than 45℃, the refrigerator and the cooling fan are turned on, and a current of 4A is input to the refrigerator, so that the hot end temperature reaches about 48℃.

[0080] According to some example embodiments of the present application, the box comprises a liquid supplement port, one end of the liquid supplement port being in communication with the liquid pool, the immersion energy storage device further comprises: a standby liquid storage structure for storing the refrigerant, the standby liquid storage structure being located outside the box and in communication with the other end of the liquid supplement port; an electromagnetic valve located on the communication pipeline between the liquid supplement port and the standby liquid storage structure; a liquid guide pipe and a circulating pump, both of which are located between the liquid pool and the liquid cooling structure in the box, one end of the liquid guide pipe being in communication with the flow guide cavity, one end of the circulating pump being in communication with one end of the liquid guide pipe, the other end of the circulating pump being in communication with the liquid inlet of the bottom plate, and the control method of the energy storage system further comprises: acquiring the temperature of the battery module; in the case that the temperature of the battery module is greater than a sixth threshold value and less than or equal to a seventh threshold value, controlling the electromagnetic valve to be in an open state and controlling the circulating pump to be in a closed state to inject the refrigerant from the standby liquid storage structure into the liquid pool, so that the liquid level in the liquid pool rises to a predetermined liquid level value; in the case that the temperature of the battery module is greater than the seventh threshold value, controlling the circulating pump to be in an open state, so that the refrigerant circulates in the bottom plate and the liquid guide pipe to cool the battery module. In this embodiment, by monitoring the temperature of the battery module, the system can automatically determine when to assist cooling by only increasing the amount of refrigerant in the liquid pool and when to start the circulating pump to speed up the flow and heat exchange of the refrigerant. This intelligent control strategy can dynamically adjust the cooling intensity according to the battery temperature, avoiding the situation of excessive cooling or insufficient cooling, thereby improving the overall energy efficiency ratio of the system and the safe operation of the battery; when the battery temperature is between the sixth threshold value and the seventh threshold value, only the amount of refrigerant is adjusted to improve the cooling effect, without starting the circulating pump. This method saves the additional energy consumed by the pump operation, realizes the effective use of resources, especially when the battery temperature rises slightly but has not reached a dangerous level, the problem can be solved by simply supplementing the refrigerant, improving the economy and environmental protection of the system.

[0081] In actual application, the sixth threshold value, the seventh threshold value and the predetermined liquid level value can be set according to experience values or obtained through multiple experiments, which are not limited in the present application. In the embodiments of the present application, the sixth threshold value is 33℃ and the seventh threshold value is 36℃.

[0082] Specifically, when the cell temperature Tc is 33℃<Tc<36℃, the electromagnetic valve is opened to inject the refrigerant from the standby liquid storage structure, so that the liquid level of the liquid pool rises to 3 / 4 of the depth of the liquid pool, thereby increasing the contact area between the cell surface and the refrigerant and enhancing the heat exchange effect; when Tc>36℃, the circulating pump is opened, so that the refrigerant in the flow channel can circulate, and the refrigerant in the flow state can form a good cooling effect on the bottom of the cell.

[0083] In other embodiments, the submerged energy storage device further comprises a constant pressure valve connected to the liquid storage tank, and the control method of the energy storage system further comprises: acquiring the internal pressure of the battery module, the charging and discharging power of the battery module, and the external environment temperature; and adjusting the pressure of the gas phase space of the liquid storage tank through the constant pressure valve according to the internal pressure of the battery module, the charging and discharging power of the battery module, and the external environment temperature. In this embodiment, by monitoring the internal pressure of the battery module, combining the charging and discharging power of the battery module and the external environment temperature, the pressure of the gas phase space of the liquid storage tank is intelligently adjusted to ensure that the refrigerant evaporates and condenses in the best state, thereby improving the heat dissipation efficiency.

[0084] Those skilled in the art can understand that the embodiments are specific embodiments for implementing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be limited by the scope defined by the claims.

Claims

1. A submersible energy storage device, characterized in that, include: Box; A battery module is located in the housing, and the battery module includes multiple battery cells with a gap between two adjacent battery cells. A liquid cooling structure is located in the housing. The liquid cooling structure includes a bottom plate located at the bottom of the battery module. The bottom plate is provided with a flow guiding cavity and a liquid inlet. The flow guiding cavity is connected to the gap and the liquid inlet respectively. A liquid storage tank, located on one side of the liquid cooling structure in the housing, is used to store refrigerant. The outlet of the liquid storage tank is connected to the inlet of the bottom plate, and the refrigerant flows into the guide cavity and the gap through the inlet of the bottom plate. A refrigerator includes a cold end and a hot end, wherein the cold end is located on the side of the opening of the liquid storage tank in the housing, and the hot end is located outside the housing; A cooling fan is located outside the housing, and the cooling fan blows air towards the hot end; The base plate includes a flow channel portion and a support portion extending along a first direction. Two support portions are located on both sides of the flow channel portion along a second direction. The guide cavity is located between the flow channel portion and the support portion. One end of the flow channel portion near the liquid storage tank is connected to the liquid inlet of the base plate, and the other end of the flow channel portion away from the liquid storage tank is connected to the guide cavity. The first direction and the second direction intersect. The liquid cooling structure also includes two side plates arranged opposite each other along the first direction. The two side plates are respectively connected to the bottom plate, and the battery module is located between the two side plates and is in contact with the two side plates respectively.

2. The submersible energy storage device according to claim 1, characterized in that, The housing has a bottom surface and a top surface, the liquid storage tank is located on the bottom surface, the cold end is located on the top surface, and the surface of the cold end has a first position and a second position arranged sequentially along the direction from the liquid cooling structure to the liquid storage tank. The distance from the first position to the liquid storage tank is greater than the distance from the second position to the liquid storage tank.

3. The submersible energy storage device according to claim 1, characterized in that, The liquid level of the refrigerant in the storage tank and the gap is the same. The tank is provided with a liquid replenishment port, one end of which is connected to the storage tank. The submersible energy storage device also includes: A backup liquid storage structure is provided for storing the refrigerant. The backup liquid storage structure is located outside the housing and is connected to the other end of the liquid replenishment port. A solenoid valve is located on the connecting pipeline between the replenishment port and the backup liquid storage structure.

4. The submersible energy storage device according to claim 3, characterized in that, Before the solenoid valve is opened, the liquid level of the refrigerant in the liquid storage tank is 1 / 2 to 2 / 3 of the depth of the liquid storage tank.

5. The submersible energy storage device according to claim 1, characterized in that, The submersible energy storage device also includes: An electric heater is located in the liquid storage tank; The liquid guide pipe and the circulation pump are both located between the liquid storage tank and the liquid cooling structure in the housing. One end of the liquid guide pipe is connected to the flow guide cavity, one end of the circulation pump is connected to one end of the liquid guide pipe, and the other end of the circulation pump is connected to the liquid inlet of the bottom plate. The circulation pump is used to make the refrigerant circulate in the bottom plate and the liquid guide pipe.

6. The submersible energy storage device according to claim 1, characterized in that, The refrigerant includes R134a refrigerant, and the submerged energy storage device further includes: A constant pressure controller, connected to the housing, is used to control the pressure inside the housing to be maintained at 4.5~5.5 bar.

7. The submersible energy storage device according to claim 1, characterized in that, Multiple battery cells are arranged at intervals along the first direction. Two spacers are provided at intervals between two adjacent battery cells in the second direction. The two spacers create a gap between two adjacent battery cells and close the gap in the second direction. The gap overlaps with the flow guide cavity in the third direction. The bottom edge of the battery cell in the first direction contacts the support portion. The third direction is the arrangement direction of the liquid storage tank and the cold end.

8. An energy storage system, characterized in that, include: The submersible energy storage device according to any one of claims 1 to 7.

9. A control method for an energy storage system, characterized in that, The energy storage system is the energy storage system according to claim 8, and the control method of the energy storage system includes: Obtain the ambient temperature; The on / off state of the cooler and cooling fan is controlled at least according to the ambient temperature to perform thermal management of the battery module.

10. The control method for the energy storage system according to claim 9, characterized in that, Controlling the on / off state of the cooler and cooling fan based at least on the ambient temperature includes: When the ambient temperature is greater than a first threshold and less than or equal to a second threshold, the cooler and the cooling fan are controlled to be in a closed state. When the ambient temperature is greater than the second threshold, the cooler and the cooling fan are turned on, and the current supplied to the cooler is controlled according to the ambient temperature so that the hot end temperature of the cooler is greater than the ambient temperature.

11. The control method for an energy storage system according to claim 10, characterized in that, Controlling the current supplied to the cooler based on the ambient temperature includes: When the ambient temperature is greater than the second threshold and less than or equal to the third threshold, the cooler and the cooling fan are controlled to be turned on, and a first current is supplied to the cooler. When the ambient temperature is greater than the third threshold and less than or equal to the fourth threshold, the cooler and the cooling fan are controlled to be turned on, and a second current is supplied to the cooler. When the ambient temperature is greater than the fourth threshold and less than the fifth threshold, the cooler and the cooling fan are controlled to be turned on, and a third current is supplied to the cooler, wherein the first current, the second current and the third current increase sequentially.

12. The control method for the energy storage system according to claim 10, characterized in that, The submersible energy storage device also includes an electric heater located in the storage tank, and the control method of the energy storage system further includes: When the ambient temperature is less than or equal to the first threshold, the electric heater is turned on to heat the refrigerant in the liquid storage tank, and the cooler and the cooling fan are kept off.

13. The control method for the energy storage system according to claim 9, characterized in that, The housing includes a liquid inlet, one end of which is connected to the liquid storage tank. The submerged energy storage device further includes: a backup liquid storage structure for storing the refrigerant, the backup liquid storage structure being located outside the housing and connected to the other end of the liquid inlet; a solenoid valve located on the connecting pipe between the liquid inlet and the backup liquid storage structure; a liquid guide pipe and a circulation pump, both located between the liquid storage tank and the liquid cooling structure within the housing, one end of the liquid guide pipe being connected to the flow guiding cavity, one end of the circulation pump being connected to one end of the liquid guide pipe, and the other end of the circulation pump being connected to the liquid inlet of the base plate. The control method of the energy storage system further includes: Obtain the temperature of the battery module; When the temperature of the battery module is greater than the sixth threshold and less than or equal to the seventh threshold, the solenoid valve is controlled to be in the open state and the circulation pump is controlled to be in the closed state, so as to inject the refrigerant from the backup liquid storage structure into the liquid storage tank, so that the liquid level in the liquid storage tank rises to a predetermined liquid level value. When the temperature of the battery module exceeds the seventh threshold, the circulation pump is turned on to allow the refrigerant to circulate in the base plate and the liquid guide pipe to cool the battery module.

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