Energy storage system and cooling cycle method

Abstract

The embodiment of the invention relates to the field of energy storage, and provides an energy storage system and a cooling circulation method, and the energy storage system comprises a liquid cooling unit which is provided with a liquid outlet and a liquid return port; the battery cluster is communicated with the first liquid outlet pipe through a second liquid outlet pipe, the battery cluster is communicated with the first liquid return pipe through a second liquid return pipe, and the liquid cooling unit is used for providing a cooling medium for the battery cluster through the liquid outlet and is also used for recovering the cooling medium in the battery cluster through the liquid return port; the degassing device is connected between the liquid cooling unit and the battery cluster; and each first detection device is communicated with one battery cluster and is used for detecting the substance amount of the gas in the cooling medium in each battery cluster, and when the substance amount of the gas in the cooling medium exceeds a first preset value, the degassing device and the battery clusters are communicated. The reliability of the energy storage system can be improved.

Description

[0001] Cross - Reference to Related Applications

[0002] This application is a divisional application of a Chinese patent application with an application date of December 4, 2024, an application number of 202411768378.6, and an invention title of "Energy Storage System and Cooling Cycle Method". Technical Field

[0003] Embodiments of the present disclosure relate to the field of energy storage, and particularly to an energy storage system and a cooling cycle method. Background Art

[0004] An energy storage system is equipped with battery cells. During the charging and discharging process of the battery cells, heat is generated, causing the temperature of the battery cells to rise. If the temperature of the battery cells is not controlled, it may lead to a decrease in the efficiency of the battery cells, a reduction in lifespan, or thermal runaway. The natural heat dissipation of the battery cells cannot maintain the temperature within the working range, so an external cooling system must be provided.

[0005] Immersion liquid cooling is a cooling system applied to energy storage devices. By filling the battery pack with an insulating immersion cooling medium, the cooling medium directly contacts the battery cells for heat exchange. In the energy storage system, there are liquid cooling units and liquid cooling pipelines. The immersion cooling medium flows in the pipelines, and the liquid cooling units cool the cooling medium to control the temperature of the battery cells. Immersion liquid cooling has good temperature control effects and safety, can better reduce the temperature difference between battery cells, and reduce the risk of thermal runaway. It is a very promising liquid cooling technology for energy storage devices.

[0006] Currently, there are certain safety risks in the immersion liquid cooling solution. Summary of the Invention

[0007] Embodiments of the present disclosure provide an energy storage system and a cooling cycle method, which can at least improve the reliability of the energy storage system.

[0008] According to some embodiments of the present disclosure, on one hand, an energy storage system is provided in the embodiments of the present disclosure, comprising: a liquid cooling unit, the liquid cooling unit having a liquid outlet and a liquid return port, and the liquid outlet is connected to a first liquid outlet pipe, and the liquid return port is connected to the first liquid return pipe; m clusters of battery clusters, the battery cluster is connected to the first liquid outlet pipe via a second liquid outlet pipe, the second liquid outlet pipe is provided with a first valve, the battery cluster is connected to the first liquid return pipe via a second liquid return pipe, and the second liquid return pipe is provided with a second valve, wherein the liquid cooling unit is used to provide a cooling medium to the battery cluster via the liquid outlet, and is also used to recover the cooling medium in the battery cluster via the liquid return port, and m is an integer greater than or equal to 1; a degassing device, the degassing device is connected between the liquid cooling unit and the battery cluster; m first detection devices, one of the first detection devices is connected to a cluster of the battery clusters, and is used to detect the amount of gaseous substance in the cooling medium in each cluster of the battery clusters, and when the amount of gaseous substance in the cooling medium exceeds a first preset value, the degassing device and the battery cluster are connected.

[0009] In some embodiments, the second liquid return pipe includes: a first branch pipe and a second branch pipe, the first branch pipe is connected to the first liquid return pipe, the second branch pipe is connected to the degassing device, and is connected to the first liquid return pipe through the degassing device. During the normal operating mode, the second branch pipe is closed and the first branch pipe is connected. During the degassing mode, the second branch pipe is connected and the first branch pipe is closed.

[0010] In some embodiments, it also includes: a battery management system, which is used to control the energy storage system to switch from a normal operating mode to a degassing mode when the energy storage system meets a preset condition. During the degassing mode, the cooling medium passes through the degassing device, and the degassing device works to remove gas from the cooling medium passing through the degassing device.

[0011] In some embodiments, the first detection device is further used to: when it is detected that the amount of gaseous substance in the cooling medium exceeds a second preset value, output a judgment signal to the battery management system, and the battery management system judges whether the energy storage system meets the preset conditions. When the energy storage system meets the preset conditions, the energy storage system is controlled to switch from the normal operating mode to the degassing mode; wherein the second preset value is less than the first preset value, and the preset conditions include: the time length of the energy storage system in the normal operating mode is greater than or equal to the preset time length, and / or the time difference between the current time and the next charge and discharge time is greater than the total time of a degassing mode.

[0012] In some embodiments, after the degassing device removes the gas from the cooling medium in one cluster of the battery clusters, it is then connected to another cluster of the battery clusters. The energy storage system further includes: a second detection device, which is connected to the degassing device and is used to detect the amount of substance of the gas separated from the cooling medium per unit volume in the degassing device, and control the connection time between the degassing device and the currently connected battery cluster according to the amount of substance of the separated gas, wherein the amount of substance of the separated gas is proportional to the connection time.

[0013] According to some embodiments of the present disclosure, on the other hand, the present disclosure embodiments further provide a cooling cycle method for use in an energy storage system, including: determining whether the energy storage system is in a charge-discharge state; if the energy storage system is not in a charge-discharge state, detecting the amount of substance of the gas in the cooling medium in each cluster of the battery clusters, and when the amount of substance of the gas in the cooling medium exceeds a first preset value, performing a degassing process, where the degassing process includes: controlling the connection between the battery clusters in the energy storage system and the degassing device to remove the gas dissolved in the cooling medium; if the energy storage system is in a charge-discharge state, controlling the disconnection between the battery clusters and the degassing device and controlling the connection between the battery clusters and the cooling unit.

[0014] In some embodiments, there are multiple clusters of battery clusters in the energy storage system, and the degassing process includes: sequentially controlling the connection between each cluster of the battery clusters and the degassing device to sequentially remove the gas dissolved in the cooling medium in each cluster of the battery clusters.

[0015] In some embodiments, before performing the degassing process, it further includes: determining the time until the energy storage system is next in a charge-discharge state, and if the time until the energy storage system is next in a charge-discharge state is greater than a first preset time, controlling the connection between the battery clusters in the energy storage system and the degassing device; wherein the first preset time is the time required to remove the gas dissolved in all the cooling medium in the energy storage system.

[0016] In some embodiments, if the time until the energy storage system is next in a charge-discharge state is less than the first preset time, determine the relationship between the time until the energy storage system is next in a charge-discharge state and the time required to remove the gas dissolved in the cooling medium in one cluster of the battery clusters. If the time until the energy storage system is next in a charge-discharge state is greater than the time required to remove the gas dissolved in the cooling medium in one cluster of the battery clusters, then remove the gas dissolved in N clusters of the battery clusters, where N is the result of rounding up the quotient obtained by dividing the time until the energy storage system is next in a charge-discharge state by the time required to remove the gas dissolved in the cooling medium in one cluster of the battery clusters.

[0017] In some embodiments, before removing the gas dissolved in the cooling medium in N clusters of the battery clusters, it further includes: obtaining information of the battery clusters that completed the degassing treatment last time. If all the gas dissolved in the cooling medium in the energy storage system was removed in the last degassing treatment, then in this degassing treatment, the gas dissolved in the cooling medium in the battery clusters is processed in sequence; if only part of the gas dissolved in the cooling medium in the energy storage system was removed in the last degassing treatment, then in this degassing treatment, the gas dissolved in the cooling medium in the battery clusters that were not subjected to the last degassing treatment is processed in sequence.

[0018] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages: In the normal operation mode, the cooling medium circulates between the liquid cooling unit and the battery clusters to reduce the temperature in the battery clusters. After the battery clusters operate for a period of time, part of the air will dissolve in the cooling medium, resulting in a reduction in the reliability of the energy storage system. Based on this, the amount of substance of the gas in the cooling medium in the battery clusters is detected by the first detection device, and when the amount of substance of the gas in the cooling medium exceeds the first preset value, the passage between the degassing device and the battery clusters is turned on, and the gas in the cooling medium is removed by the degassing device, thereby improving the reliability of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are illustrated by way of example in the accompanying drawings, and these illustrative descriptions do not limit the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the following described drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic structural diagram of an energy storage system provided by an embodiment of the present disclosure;

[0021] Figure 2 It is another schematic structural diagram of an energy storage system provided by an embodiment of the present disclosure;

[0022] Figure 3 It is a flowchart of a cooling cycle method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] As can be seen from the background art, air will dissolve in the cooling medium during the circulation process, resulting in the appearance of tiny air bubbles in the battery pack, forming a bubble bridge in the cooling medium, triggering the phenomenon of bubble breakdown and causing a short circuit, posing a safety risk to the system.

[0024] In the embodiments of the present disclosure, in the normal operation mode, the cooling medium circulates between the liquid cooling unit and the battery cluster to reduce the temperature inside the battery cluster. After the battery cluster operates for a period of time, part of the air will dissolve in the cooling medium, resulting in a reduction in the reliability of the energy storage system. Based on this, the battery management system will detect whether the energy storage system meets the preset conditions during the operation of the energy storage system. When the preset conditions are met, the energy storage system will be controlled to enter the degassing mode, and the gas in the cooling medium will be removed through the degassing device, thereby improving the reliability of the energy storage system.

[0025] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0026] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0028] In the description of the embodiments of the present disclosure, the term "a plurality" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of sheets" refers to more than two sheets (including two sheets).

[0029] In the description of the embodiments of the present disclosure, technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present disclosure.

[0030] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and defined, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific situations.

[0031] In the corresponding drawings of the embodiments of the present disclosure, for better understanding and convenience of description, the thickness and area of the layers are enlarged. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0032] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. In addition, when a component such as a layer, film, region, or plate is referred to as "on / at" another component, it can be "directly on" the other component (that is, on the surface of the other component and there are no other components between them), or there can be another component between them. In addition, when a layer, film, region, plate, etc. component is "directly located on" another component, or when a layer, film, region, plate, etc. component is located on the surface of another component, it means that there are no other components located between them.

[0033] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is also intended to include the plural form, unless the context clearly indicates otherwise. Among them, the component includes components such as layers, films, regions, or plates.

[0034] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are proposed for the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions required to be protected by the present disclosure can still be implemented.

[0035] Reference Figure 1 and Figure 2 , Figure 1 is a schematic structural diagram of an energy storage system provided by an embodiment of the present disclosure; Figure 2 is another schematic structural diagram of an energy storage system provided by an embodiment of the present disclosure.

[0036] In some embodiments, the energy storage system may include: a liquid cooling unit 100, the liquid cooling unit 100 having a liquid outlet 110 and a liquid return port 120, and the liquid outlet 110 communicating with a first liquid outlet pipe 130, and the liquid return port 120 communicating with a first liquid return pipe 140.

[0037] The energy storage system may further include: m battery clusters 101, the battery clusters 101 being connected to the first liquid outlet pipe 130 via a second liquid outlet pipe 111, a first valve 121 being provided on the second liquid outlet pipe 111, the battery clusters 101 being connected to the first liquid return pipe 140 via a second liquid return pipe 131, a second valve 141 being provided on the second liquid return pipe 131, wherein the liquid cooling unit 100 is configured to supply a cooling medium to the battery clusters 101 via the liquid outlet 110, and is further configured to recover the cooling medium in the battery clusters 101 via the liquid return port 120, and m is an integer greater than or equal to 1.

[0038] The energy storage system may further include: a degassing device 102, the degassing device 102 being connected between the liquid cooling unit 100 and the battery clusters 101.

[0039] The energy storage system may further include: a battery management system (not shown), the battery management system being configured to control the energy storage system to switch from a normal operation mode to a degassing mode when the energy storage system meets a preset condition, and during the degassing mode, the cooling medium passes through the degassing device 102, and the degassing device 102 operates to remove the gas in the cooling medium passing through the degassing device 102.

[0040] In the normal operation mode in the embodiments of the present disclosure, the cooling medium circulates between the liquid cooling unit 100 and the battery clusters 101 to reduce the temperature in the battery clusters 101. After the battery clusters 101 operate for a period of time, part of the air will dissolve in the cooling medium, resulting in a reduction in the reliability of the energy storage system. Based on this, the battery management system will detect whether the energy storage system meets the preset condition during the operation of the energy storage system. When the preset condition is met, the energy storage system is controlled to enter the degassing mode, and the gas in the cooling medium is removed through the degassing device 102, thereby improving the reliability of the energy storage system.

[0041] It can be understood that in the normal operation mode, the cooling medium circulates between the liquid cooling unit 100 and the battery cluster 101. By absorbing the heat in the battery cluster 101 through the cooling medium, the temperature of the battery cluster 101 can be reduced. Then the cooling medium returns to the liquid cooling unit 100, and the liquid cooling unit 100 cools the cooling medium with rising temperature, so that the cooling medium flowing out through the liquid outlet 110 can absorb more heat, which is beneficial to controlling the temperature of the battery cluster 101 and improving the reliability of the energy storage system.

[0042] In the degassing mode, the cooling medium first passes through the degassing device 102. After the gas in the cooling medium is removed by the degassing device 102, it then returns to the liquid cooling unit 100. At this time, in the degassing mode, the first valve 121 and the second valve 141 are still in the open state, so as to avoid abnormal conditions caused by excessive pressure in the liquid cooling unit 100.

[0043] In some embodiments, during the degassing mode, the degassing device 102 is only connected to one cluster of battery clusters 101 each time for degassing. After the degassing of one cluster of battery clusters 101 is completed, it is then connected to another cluster of battery clusters 101, and the time for the degassing device 102 to be connected to each battery cluster 101 is equal. In other words, during the degassing mode, the degassing of each cluster of battery clusters 101 is carried out in sequence. By carrying out the degassing of each cluster of battery clusters 101 in sequence, it is possible to avoid the mixing between the cooling medium that has completed degassing and the cooling medium that has not completed degassing among different clusters, and avoid reducing the degassing efficiency. For example, if the total duration of the degassing mode is y and there are m clusters of battery clusters 101 in total, then the degassing duration for each cluster of battery clusters 101 is y / m. After carrying out the degassing treatment for a cluster of battery clusters 101 for a duration of y / m, another cluster of battery clusters 101 is replaced.

[0044] In some embodiments, the degassing of each cluster of battery clusters 101 in sequence can be completed through the cooperation of the first valve 121 and the second valve 141. When a cluster of battery clusters 101 is being degassed, the connection of the remaining battery clusters 101 can be disconnected by controlling the first valve 121 and the second valve 141, so as to control the cooling medium to only circulate within the battery cluster 101.

[0045] The liquid cooling unit 100 may include a cooling unit and a water pump unit. The cooling unit can cool the cooling medium flowing into the liquid cooling unit 100, and the water pump unit can drive the cooling medium to flow between the liquid cooling unit 100 and the battery cluster 101.

[0046] Each battery cluster 101 may include multiple battery packs, and the multiple battery packs are electrically connected. In some embodiments, the energy storage system cools the battery pack by immersion liquid cooling, and the entire battery pack is directly immersed in the cooling medium, and the cooling medium and the battery pack are directly controlled to exchange heat; in other embodiments, the cooling medium flows through the interior of the battery pack, and the liquid cooling pipes of each battery pack are interconnected. The cooling medium circulates in different battery packs through the liquid cooling pipes to cool each battery pack.

[0047] In some embodiments, the second liquid return pipe 131 includes: a first branch pipe 151 and a second branch pipe 161, the first branch pipe 151 is connected to the first liquid return pipe 140, the second branch pipe 161 is connected to the degassing device 102, and is connected to the first liquid return pipe 140 through the degassing device 102. During the normal operating mode, the second branch pipe 161 is closed and the first branch pipe 151 is connected. During the degassing mode, the second branch pipe 161 is connected and the first branch pipe 151 is closed.

[0048] That is to say, in the normal operating mode, the battery cluster 101 is connected to the liquid cooling unit 100 via the first branch pipe 151, and in the degassing mode, the battery cluster 101 is connected to the liquid cooling unit 100 via the second branch pipe 161, and the second branch pipe 161 is also connected to the degassing device 102, so that in the degassing mode, the cooling medium returns to the liquid cooling unit 100 after passing through the degassing device 102. By setting the second liquid return pipe 131 including the first branch pipe 151 and the second branch pipe 161, the flow routes of the cooling liquid in different operating modes can be distinguished, which can facilitate the switching between the normal operating mode and the degassing mode.

[0049] In some embodiments, the energy storage system may further include: a third valve 171, which is disposed between the first branch pipe 151 and the first liquid return pipe 140, and is used to control the conduction and closure of the first branch pipe 151; and a fourth valve 181, which is disposed between the second branch pipe 161 and the degassing device 102, and is used to control the conduction and closure of the second branch pipe 161. By controlling the conduction and closure of the third valve 171 and the fourth valve 181, the switching of the energy storage system between the normal operation mode and the degassing mode can be controlled.

[0050] The third valve 171 and the fourth valve 181 may also be controlled by the battery management system, so that the energy storage system can be operated automatically, thereby reducing labor costs and the risk of control errors.

[0051] The degassing device 102 can be a vacuum degasser, which uses vacuum suction to remove the gas in the cooling medium, thereby avoiding the formation of a bubble bridge in the cooling medium and preventing the occurrence of the bubble breakdown phenomenon. By using the degassing device 102, the safety and reliability of the energy storage system can be improved.

[0052] The battery management system can be used to control whether the battery cluster 101 outputs a power signal, and can also control the opening and closing of the first valve 121, etc.

[0053] In some embodiments, the preset conditions may include: the duration of the system in the normal operation mode is greater than or equal to the preset duration, and / or, the time difference between the current time and the next charge and discharge time is greater than the total time of one degassing mode, and / or, the system is not in the charge and discharge state. The battery management system can select different control modes according to the satisfaction of the above different conditions. For example, when the system is not in the charge and discharge state, but the time difference between the current time and the next charge and discharge time is less than the total time of one degassing mode, the battery management system can control the degassing treatment of the cooling medium in some of the battery clusters 101.

[0054] In the battery management system, the time of the preset duration and the total time required for one degassing mode can be entered in advance, and the time when the energy storage system is in the normal operation mode can be detected, so as to complete the switch from the normal operation mode to the degassing mode.

[0055] In some embodiments, the energy storage system may further include: m first detection devices 103, one first detection device 103 is connected to one cluster of battery clusters 101, and is used to detect the amount of substance of the gas in the cooling medium in each cluster of battery clusters 101. When the amount of substance of the gas in the cooling medium exceeds the first preset value, a control signal is output to the battery management system, and the battery management system forcibly switches from the normal operation mode to the degassing mode. When the amount of substance of the gas in the cooling medium exceeds the first preset value, it indicates that the possibility of the occurrence of a bubble bridge causing bubble breakdown in the energy storage system is relatively high at this time. Continuing the normal operation mode at this time may cause abnormalities in the entire energy storage system. Based on this, a control signal is sent to the battery management system, so as to facilitate the battery management system to control the operation of the energy storage system. By detecting each cluster of battery clusters 101 through the first detection device 103, it is convenient for the energy storage system to switch between different operation modes, and further improves the reliability of the energy storage system.

[0056] In some embodiments, the first detection device 103 is further configured to: when detecting that the amount of substance of the gas in the cooling medium exceeds a second preset value, output a judgment signal to the battery management system, and the battery management system determines whether the energy storage system meets a preset condition. When the energy storage system meets the preset condition, control the energy storage system to switch from the normal operation mode to the degassing mode; wherein, the second preset value is less than the first preset value, and the preset condition includes: the duration of the energy storage system in the normal operation mode is greater than or equal to a preset duration, and / or, the time difference between the current time and the next charge-discharge time is greater than the total time of one degassing mode. When the amount of substance of the gas in the cooling medium exceeds the second preset value, it indicates that there is already a relatively large amount of gas in the cooling medium at this time, and there is a certain safety hazard, and degassing treatment is required. At this time, a judgment signal is sent to notify the battery management system. When the battery management system determines that the energy storage system meets the preset condition, it controls the energy storage system to switch to the degassing mode. When the energy storage system does not meet the preset condition, it continues to detect and switches to the degassing mode after the energy storage system meets the preset condition.

[0057] In some embodiments, after the degassing device 102 removes the gas from the cooling medium in a cluster of battery clusters 101, it is then connected to another cluster of battery clusters 101. The energy storage system further includes: a second detection device 104, which is connected to the degassing device 102 and is configured to detect the amount of substance of the gas separated from the cooling medium per unit volume in the degassing device 102, and control the connection time of the degassing device 102 to the currently connected battery cluster 101 according to the amount of substance of the separated gas, wherein the amount of substance of the separated gas is proportional to the connection time. In other words, the more gas contained in the cooling medium in different battery clusters 101, the longer the degassing time, so as to facilitate the allocation of the degassing mode to process the time of each battery cluster 101, and thus further reduce the gas content in the cooling medium after the degassing mode and improve the reliability of the energy storage system.

[0058] In some embodiments, the energy storage system further includes: a temperature monitoring device (not shown), which is configured to detect the temperature in each cluster of battery clusters 101 during the degassing mode. When the temperature in the battery cluster 101 is higher than a preset temperature, an alarm signal is output to the battery management system, and the battery management system controls the energy storage system to switch from the degassing mode to the normal operation mode. By monitoring the temperature in the battery cluster 101, abnormal conditions caused by too high temperature in the battery cluster 101 can be avoided, so as to improve the reliability of the energy storage system.

[0059] In some embodiments, during the degassing mode, degassing is performed on each cluster of battery clusters 101 in sequence. At this time, the cooling medium in the battery cluster 101 that has not been degassed circulates inside the battery cluster 101. At this time, if the degassing mode is too long, it may cause the temperature in the battery cluster 101 that has not been degassed to continue to rise. Therefore, the battery cluster 101 is monitored by a temperature monitoring device, so as to avoid the abnormal situation caused by the excessive temperature of the battery cluster 101 during the degassing mode.

[0060] In the normal operation mode of the embodiments of the present disclosure, the cooling medium circulates reciprocally between the liquid cooling unit 100 and the battery cluster 101 to reduce the temperature inside the battery cluster 101. After the battery cluster 101 operates for a period of time, part of the air will dissolve in the cooling medium, resulting in a reduction in the reliability of the energy storage system. Based on this, the battery management system will detect whether the energy storage system meets the preset conditions during the operation of the energy storage system. When the preset conditions are met, the energy storage system is controlled to enter the degassing mode, and the degassing device 102 is used to remove the gas in the cooling medium, thereby improving the reliability of the energy storage system.

[0061] Another embodiment of the present disclosure also provides a cooling cycle method, which can be implemented by the energy storage system in some or all of the above embodiments. The cooling cycle method provided in another embodiment of the present disclosure will be described below. It should be noted that for the same or corresponding parts in the foregoing embodiments, reference may be made to the corresponding descriptions in the foregoing embodiments, and details will not be repeated below.

[0062] Reference Figure 3 , Figure 3 is a flowchart of the cooling cycle method provided in an embodiment of the present disclosure.

[0063] In some embodiments, the cooling cycle method for the energy storage system may include: Step S10: Determine whether the energy storage system is in a charging or discharging state.

[0064] Step S11: If the energy storage system is not in a charging or discharging state, perform degassing treatment, and the degassing treatment includes: controlling the connection between the battery cluster in the energy storage system and the degassing device to remove the gas dissolved in the cooling medium; if the energy storage system is in a charging or discharging state, controlling the disconnection between the battery cluster and the degassing device, and controlling the connection between the battery cluster and the cooling unit.

[0065] By determining whether the energy storage system is in a charging or discharging state to determine whether the cooling medium in the battery cluster can be degassed, it is possible to avoid affecting the normal operation of the energy storage system and avoid the situation of temporary power failure of the energy storage system. When the energy storage system is not in a charging or discharging state, the cooling medium can be degassed by the degassing device, thereby increasing the reliability of the energy storage system.

[0066] In some embodiments, there are multiple clusters of battery clusters in the energy storage system. The degassing process includes: sequentially controlling each cluster of battery clusters to communicate with the degassing device to sequentially remove the gas dissolved in the cooling medium in each cluster of battery clusters. That is to say, during the degassing process, the degassing process is completed for one battery cluster after another, so as to avoid mixing the cooled medium after degassing with the cooled medium that has not been degassed, and avoid reducing the degassing efficiency of the entire degassing process.

[0067] That is to say, when removing the gas dissolved in the cooling medium in any one battery cluster, disconnect the connection between the remaining battery clusters and the battery cluster undergoing the degassing process.

[0068] In some other embodiments, multiple clusters of battery clusters can also be degassed simultaneously.

[0069] In some embodiments, before performing the degassing process, it further includes: judging the time until the energy storage system is next in the charge and discharge state. If the time until the energy storage system is next in the charge and discharge state is greater than a first preset time, control the battery clusters in the energy storage system to communicate with the degassing device; wherein, the first preset time is the time required to remove the gas dissolved in all the cooling medium in the energy storage system. That is to say, when the energy storage system can complete the removal of the gas in the cooling medium of all battery clusters by the time it is next in the charge and discharge state, the degassing process is performed to remove all the gas in the cooling medium of all battery clusters in one degassing process. By removing all the gas in the cooling medium of all battery clusters at once, the percentage of gas removal can be increased, thereby improving the efficiency and effect of the degassing process.

[0070] In some embodiments, if the time until the energy storage system is next in the charge and discharge state is less than the first preset time, judge the relationship between the time until the energy storage system is next in the charge and discharge state and the time required to remove the gas dissolved in the cooling medium in one cluster of battery clusters. If the time until the energy storage system is next in the charge and discharge state is greater than the time required to remove the gas dissolved in the cooling medium in one cluster of battery clusters, then remove the gas dissolved in the cooling medium in N clusters of battery clusters, where N is the integer obtained by dividing the time until the energy storage system is next in the charge and discharge state by the time required to remove the gas dissolved in the cooling medium in one cluster of battery clusters. In other words, in one degassing process, it is not necessary to remove all the battery clusters, but only the number of clusters of battery clusters that can have the gas dissolved in the cooling medium removed. In this way, during the subsequent process of converging the cooling medium to the liquid cooling unit and then outputting it to each battery cluster through the liquid cooling unit, the content of gas in the cooling medium in each cluster of battery clusters will be reduced, thereby improving the reliability of the energy storage system.

[0071] In some embodiments, before removing the gas dissolved in the cooling medium within the N battery clusters, the following steps are further included: obtaining information of the battery cluster that completed the degassing process last time; if all the gas dissolved in the cooling medium within the energy storage system was removed during the last degassing process, then during this degassing process, the gas dissolved in the cooling medium within the battery clusters is processed in sequence; if only part of the gas dissolved in the cooling medium within the energy storage system was removed during the last degassing process, then during this degassing process, the gas dissolved in the cooling medium within the battery clusters that were not processed during the last degassing process is processed in sequence. That is to say, before performing the degassing process, first detect the process of the last degassing process. If all the cooling medium within all the battery clusters has been degassed during the last degassing process, then during this degassing process, the gas contained in the cooling medium within any battery cluster can be removed. If not all the battery clusters were degassed during the last degassing process, then during this degassing process, select from the battery clusters that were not degassed during the last degassing process. Thus, when the time until the next charge-discharge state of the energy storage system is less than the first preset time and greater than the second preset time, different battery clusters are processed as much as possible, thereby avoiding the cooling medium within a certain battery cluster not being degassed for a long time and preventing any battery cluster from malfunctioning, thereby improving the reliability of the energy storage system.

[0072] In some embodiments, before performing the degassing process, the following steps are further included: determining the time that the energy storage system has been in the normal operation mode. If the time that the energy storage system has been in the normal operation mode is greater than the second preset time, then control the battery clusters in the energy storage system to be connected to the degassing device; if the time that the energy storage system has been in the normal operation mode is less than the second preset time, control the battery clusters to remain disconnected from the degassing device; wherein, the energy storage system being in the normal operation mode means that the energy storage system has been started but is not in the charge-discharge state, and the cooling medium circulates between the battery clusters and the liquid cooling unit. When the time that the energy storage system has been in the normal operation mode is greater than the second preset time, it indicates that the energy storage system has been operating for a period of time, and inevitably, a certain amount of gas bubbles are contained in the cooling medium within the battery clusters, and degassing is required to improve the reliability of the energy storage system. Moreover, by determining whether the time that the energy storage system has been in the normal operation mode is greater than the second preset time, it is also possible to avoid the degassing process affecting the normal operation time of the energy storage system.

[0073] A specific example will be given below to illustrate the cooling cycle method provided by the embodiments of the present disclosure. When the system is operating normally, the cooling unit is in a working state, the first valve and the second valve in the battery cluster are both in an open state, the passage between the degassing device and the battery cluster is disconnected, it is determined whether the energy storage system is in a charge-discharge state, it is determined whether the time for the energy storage system to be in a normal operation mode is greater than a second preset time, and it is determined whether the time for the energy storage system to be in a charge-discharge state next time is greater than a first preset time. When the above conditions are met, the passage between the degassing device and the battery cluster is controlled to be opened, and each battery cluster is sequentially controlled to be connected to the degassing device to degas the cooling medium in each battery cluster in turn.

[0074] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure. In actual applications, various changes can be made in form and details without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the protection scope of the embodiments of the present disclosure should be subject to the scope defined by the claims.

Claims

1. An energy storage system, characterized in that: include: A liquid cooling unit, wherein the liquid cooling unit has a liquid outlet and a liquid return port, wherein the liquid outlet is connected to a first liquid outlet pipe, and the liquid return port is connected to a first liquid return pipe; m battery clusters, the battery clusters are connected to the first liquid outlet pipe via a second liquid outlet pipe, the second liquid outlet pipe is provided with a first valve, the battery clusters are connected to the first liquid return pipe via a second liquid return pipe, the second liquid return pipe is provided with a second valve, wherein the liquid cooling unit is used to provide cooling medium to the battery cluster via the liquid outlet, and is also used to recover the cooling medium in the battery cluster via the liquid return port, m is an integer greater than or equal to 1; A degassing device, the degassing device is connected between the liquid cooling unit and the battery cluster; m first detection devices, one of which is connected to a cluster of the battery clusters and is used to detect the amount of the gas substance in the cooling medium in each cluster of the battery clusters. When the amount of the gas substance in the cooling medium exceeds a first preset value, the degassing device and the battery cluster are connected.

2. The energy storage system according to claim 1, characterized in that: Also includes: A battery management system, wherein the battery management system is used to control the energy storage system to switch from a normal operating mode to a degassing mode when the energy storage system meets a preset condition. During the degassing mode, the cooling medium passes through the degassing device, and the degassing device works to remove gas from the cooling medium passing through the degassing device.

3. The energy storage system according to claim 2, characterized in that: The second liquid return pipe includes: a first branch pipe and a second branch pipe, the first branch pipe is connected to the first liquid return pipe, the second branch pipe is connected to the degassing device, and is connected to the first liquid return pipe through the degassing device. During the normal operation mode, the second branch pipe is closed and the first branch pipe is connected. During the degassing mode, the second branch pipe is connected and the first branch pipe is closed.

4. The energy storage system according to claim 2, characterized in that: The first detection device is further used to: when it is detected that the amount of the gas in the cooling medium exceeds a second preset value, output a judgment signal to the battery management system, and the battery management system judges whether the energy storage system meets the preset condition, and when the energy storage system meets the preset condition, control the energy storage system to switch from the normal operation mode to the degassing mode; Among them, the second preset value is less than the first preset value, and the preset conditions include: the time length of the energy storage system in the normal operating mode is greater than or equal to the preset time length, and / or the time difference between the current time and the next charge and discharge time is greater than the total time of a degassing mode.

5. The energy storage system according to claim 1, characterized in that: The degassing device removes the gas of the cooling medium in one battery cluster and then communicates with another battery cluster. The energy storage system also includes: A second detection device is connected to the degassing device, and is used to detect the amount of gaseous substance separated from the cooling medium per unit volume in the degassing device, and control the connection time between the degassing device and the battery cluster currently connected according to the amount of the separated gaseous substance, wherein the amount of the separated gaseous substance is proportional to the connection time.

6. A cooling cycle method for use in an energy storage system, characterized in that: include: Determining whether the energy storage system is in a charging or discharging state; If the energy storage system is not in a charge and discharge state, the amount of gaseous substance in the cooling medium in each battery cluster is detected. When the amount of gaseous substance in the cooling medium exceeds a first preset value, degassing is performed. The degassing includes: controlling the battery clusters in the energy storage system to be connected to a degassing device to remove the gas dissolved in the cooling medium; if the energy storage system is in a charge and discharge state, controlling the battery clusters to be disconnected from the degassing device and controlling the battery clusters to be connected to a cooling unit.

7. The cooling cycle method according to claim 6, characterized in that: There are multiple battery clusters in the energy storage system, and the degassing process includes: sequentially controlling each battery cluster to communicate with the degassing device to sequentially remove the gas dissolved in the cooling medium in each battery cluster.

8. The cooling cycle method according to claim 6 or 7, characterized in that: Before the degassing treatment is performed, the method further comprises: Determine the time from the energy storage system to the next time it is in the charge-discharge state, and if the time from the energy storage system to the next time it is in the charge-discharge state is greater than a first preset time, control the battery cluster in the energy storage system to be connected to the degassing device; The first preset time is the time required to remove all gases dissolved in the cooling medium in the energy storage system.

9. The cooling cycle method according to claim 8, characterized in that: If the time from the energy storage system to the next charge and discharge state is less than the first preset time, the relationship between the time from the energy storage system to the next charge and discharge state and the time required to remove the gas dissolved in the cooling medium in a cluster of the battery clusters is determined; if the time from the energy storage system to the next charge and discharge state is greater than the time required to remove the gas dissolved in the cooling medium in a cluster of the battery clusters, the gas dissolved in the cooling medium in N clusters of the battery clusters is removed, where N is the integer of the result obtained by dividing the time from the energy storage system to the next charge and discharge state by the time required to remove the gas dissolved in the cooling medium in a cluster of the battery clusters.

10. The cooling cycle method according to claim 9, characterized in that: Before removing the gas dissolved in the cooling medium in the N battery clusters, the method further includes: Acquire information of the battery cluster that completed the degassing treatment last time, if the degassing treatment last time removed all gases dissolved in the cooling medium in the energy storage system, then the degassing treatment this time sequentially treats the gases dissolved in the cooling medium in the battery cluster; If the last degassing treatment removes part of the gas dissolved in the cooling medium in the energy storage system, the current degassing treatment sequentially treats the gas dissolved in the cooling medium in the battery cluster that has not been degassed in the last degassing treatment.

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