Energy storage system and cooling cycle method

Abstract

The disclosed embodiment relates to the field of energy storage, and provides an energy storage system and a cooling cycle method, wherein the energy storage system comprises: a liquid cooling unit having a liquid outlet and a liquid return port; a battery cluster is connected to a first liquid outlet via a second liquid outlet pipe, and the battery cluster is connected to a first liquid return pipe via a second liquid return pipe, 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; a degassing device, the degassing device is connected between the liquid cooling unit and the battery cluster; a battery management system, 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 the gas in the cooling medium passing through the degassing device. The reliability of the energy storage system can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of energy storage, and in particular to an energy storage system and a cooling cycle method. Background Art

[0002] The energy storage system is equipped with battery cells. The battery cells will generate heat during the charging and discharging process, causing the battery cell temperature to rise. If the temperature of the battery cells is not controlled, it may lead to reduced battery cell efficiency, shortened 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 is required.

[0003] Immersion liquid cooling is a cooling system used in energy storage devices. The battery pack is filled with an insulating immersion cooling medium, and the cooling medium is in direct contact with the battery cell for heat exchange. The energy storage system has a liquid cooling unit and liquid cooling pipelines. The immersion cooling medium flows in the pipeline and is cooled by the liquid cooling unit to control the temperature of the battery cell. Immersion liquid cooling has good temperature control effect and safety, can effectively 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.

[0004] Currently, immersion liquid cooling solutions have certain safety risks. Summary of the invention

[0005] The 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.

[0006] According to some embodiments of the present disclosure, on one hand, an energy storage system is provided according to an embodiment of the present disclosure, comprising: a liquid cooling unit, the liquid cooling unit having a liquid outlet and a liquid return port, the liquid outlet being connected to a first liquid outlet pipe, the liquid return port being connected to a first liquid return pipe; m clusters of battery clusters, the battery cluster being connected to the first liquid outlet pipe via a second liquid outlet pipe, the second liquid outlet pipe being provided with a first valve, the battery cluster being connected to the first liquid return pipe via a second liquid return pipe, the second liquid return pipe being 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 being connected between the liquid cooling unit and the battery cluster; a battery management system, the battery management system being 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 which the cooling medium passes through the degassing device, and the degassing device works to remove gas in the cooling medium passing through the degassing device.

[0007] 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.

[0008] In some embodiments, it also includes: 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, a control signal is output to the battery management system, and the battery management system is forced to switch from the normal operating mode to the degassing mode.

[0009] 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.

[0010] In some embodiments, the degassing device removes the gas of the cooling medium in one cluster of the battery cluster and then connects with another cluster of the battery cluster. The energy storage system also includes: a second detection device, which 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 currently connected battery cluster according to the amount of separated gaseous substance, wherein the amount of separated gaseous substance is proportional to the connection time.

[0011] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a cooling cycle method for use in an energy storage system, comprising: determining whether the energy storage system is in a charge and discharge state; if the energy storage system is not in a charge and discharge state, performing a degassing treatment, the degassing treatment comprising: controlling a battery cluster in the energy storage system to be connected to a degassing device to remove gas dissolved in a cooling medium; if the energy storage system is in a charge and discharge state, controlling the battery cluster to be disconnected from the degassing device, and controlling the battery cluster to be connected to a cooling unit.

[0012] In some embodiments, there are multiple battery clusters in the energy storage system, and the degassing process includes: sequentially controlling each battery cluster to be connected to the degassing device to sequentially remove the gas dissolved in the cooling medium in each battery cluster.

[0013] In some embodiments, before performing the degassing process, it also includes: judging the time from the energy storage system to the next time it is in the charge and discharge state; if the time from the energy storage system to the next time it is in the charge and discharge state is greater than a first preset time, controlling the battery cluster in the energy storage system to be connected to the degassing device; wherein the first preset time is the time required to remove the gas dissolved in all cooling media in the energy storage system.

[0014] In some embodiments, if the time from the energy storage system to the next time it is in the charge and discharge state is less than the first preset time, the relationship between the time from the energy storage system to the next time it is in the 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 time it is in the 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 time it is in the charge and discharge state by the time required to remove the gas dissolved in the cooling medium in a cluster of the battery clusters.

[0015] In some embodiments, before removing the gas dissolved in the cooling medium in the N clusters of battery clusters, the method also includes: obtaining information of the battery cluster that completed the degassing treatment last time, if the last degassing treatment removed the gas dissolved in the cooling medium in all the energy storage systems, then the degassing treatment this time sequentially treats the gas dissolved in the cooling medium in the battery cluster; if the last degassing treatment removed the gas dissolved in the cooling medium in part of the energy storage system, then the degassing treatment this time sequentially treats the gas dissolved in the cooling medium in the battery cluster that has not undergone the last degassing treatment.

[0016] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: in the normal operating mode, the cooling medium circulates back and forth in the liquid cooling unit and the battery cluster to reduce the temperature in the battery cluster. After the battery cluster has been running for a period of time, some air will dissolve in the cooling medium, resulting in reduced 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 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

[0017] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure of an energy storage system provided in one embodiment of the present disclosure;

[0019] Figure 2 Another structural schematic diagram of an energy storage system provided by an embodiment of the present disclosure;

[0020] Figure 3 A flow chart of a cooling cycle method provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] As can be seen from the background technology, air will dissolve in the cooling medium during the circulation process, resulting in tiny air bubbles in the battery pack, forming bubble bridges in the cooling medium, causing bubble breakdown and resulting in a short circuit, posing a safety risk to the system.

[0022] In the normal operating mode of the embodiment of the present disclosure, the cooling medium circulates back and forth in the liquid cooling unit and the battery cluster to reduce the temperature in the battery cluster. After the battery cluster has been running for a period of time, some air will dissolve in the cooling medium, resulting in reduced reliability of the energy storage system. Based on this, the battery management system will detect whether the energy storage system meets 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 gas in the cooling medium is removed by the degassing device, thereby improving the reliability of the energy storage system.

[0023] In the description of the embodiments of the present disclosure, 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 disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0028] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. 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 the specific circumstances.

[0029] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may exist 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 as being "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 is it formed on a partial edge of the entire surface.

[0030] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it may 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 exist in between. In addition, 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 means that no other components are located in between.

[0031] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0032] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable 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 claimed in the present disclosure can be implemented.

[0033] refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of an energy storage system provided by an embodiment of the present disclosure; Figure 2 Another schematic diagram of the structure of an energy storage system provided in one embodiment of the present disclosure.

[0034] In some embodiments, the energy storage system may include: a liquid cooling unit 100 having a liquid outlet 110 and a liquid return port 120 , wherein the liquid outlet 110 is connected to a first liquid outlet pipe 130 , and the liquid return port 120 is connected to a first liquid return pipe 140 .

[0035] The energy storage system may further include: m clusters of battery clusters 101, the battery cluster 101 being connected to the first liquid outlet pipe 130 via the second liquid outlet pipe 111, the second liquid outlet pipe 111 being provided with a first valve 121, the battery cluster 101 being connected to the first liquid return pipe 140 via the second liquid return pipe 131, the second liquid return pipe 131 being provided with a second valve 141, wherein the liquid cooling unit 100 is used to provide cooling medium to the battery cluster 101 via the liquid outlet 110, and is also used to recover the cooling medium in the battery cluster 101 via the liquid return port 120, and m is an integer greater than or equal to 1.

[0036] The energy storage system may further include: a degassing device 102 , which is connected between the liquid cooling unit 100 and the battery cluster 101 .

[0037] The energy storage system may further include: a battery management system (not shown), the battery management system being used to control the energy storage system to switch from a normal operating mode to a degassing mode when the energy storage system meets preset conditions, during which the cooling medium passes through the degassing device 102, and the degassing device 102 works to remove gas from the cooling medium passing through the degassing device 102.

[0038] In the normal operation mode of the embodiment of the present disclosure, the cooling medium circulates back and forth in the liquid cooling unit 100 and the battery cluster 101 to reduce the temperature in the battery cluster 101. After the battery cluster 101 has been running for a period of time, some air will dissolve in the cooling medium, resulting in reduced 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 gas in the cooling medium is removed by the degassing device 102, thereby improving the reliability of the energy storage system.

[0039] It can be understood that in the normal operation mode, the cooling medium circulates back and forth in the liquid cooling unit 100 and the battery cluster 101, and the cooling medium absorbs the heat in the battery cluster 101 to achieve cooling of the battery cluster 101. The cooling medium then returns to the liquid cooling unit 100, and the liquid cooling unit 100 cools the cooling medium with increased 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.

[0040] In the degassing mode, the cooling medium will first pass through the degassing device 102, and then return to the liquid cooling unit 100 after the gas in the cooling medium is removed by the degassing device 102. At this time, in the degassing mode, the first valve 121 and the second valve 141 are still in an open state, so as to avoid abnormalities caused by excessive pressure in the liquid cooling unit 100.

[0041] In some embodiments, during the degassing mode, the degassing device 102 is connected to only one battery cluster 101 at a time for degassing, and after completing the degassing of one battery cluster 101, it is connected to another battery cluster 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, each battery cluster 101 is degassed in sequence. By degassing each battery cluster 101 in sequence, it is possible to avoid mixing between the cooling medium that has been degassed and the cooling medium that has not been degassed between different clusters, thereby avoiding a reduction in degassing efficiency. For example, the total duration of the degassing mode is y, and there are a total of m battery clusters 101, then the degassing duration of each battery cluster 101 is y / m, and after degassing one battery cluster 101 for y / m time, another battery cluster 101 is replaced.

[0042] In some embodiments, the first valve 121 and the second valve 141 can cooperate to sequentially degas each battery cluster 101. When one battery cluster 101 is degassed, the remaining battery clusters 101 can be disconnected by controlling the first valve 121 and the second valve 141, so that the cooling medium can only circulate within the battery cluster 101.

[0043] The liquid cooling unit 100 may include: a cooling unit and a water pump unit. The cooling unit may cool down the cooling medium flowing into the liquid cooling unit 100 , and the water pump unit may drive the cooling medium to flow between the liquid cooling unit 100 and the battery cluster 101 .

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The degassing device 102 may be a vacuum degasser, which utilizes vacuum suction to remove gas from the cooling medium, thereby avoiding the formation of bubble bridges in the cooling medium that may cause bubble breakdown. The use of the degassing device 102 may improve the safety and reliability of the energy storage system.

[0050] 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 and the like.

[0051] In some embodiments, the preset conditions may include: the duration of the system being 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 a degassing mode, and / or the system is not in the charge and discharge state. The battery management system may 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 a degassing mode, the battery management system may control the cooling medium in part of the battery cluster 101 to perform degassing.

[0052] The preset duration and the total time required for a degassing mode can be entered in advance in the battery management system, and the time when the energy storage system is in the normal operating mode can be detected, thereby completing the switch from the normal operating mode to the degassing mode.

[0053] In some embodiments, the energy storage system may further include: m first detection devices 103, one first detection device 103 is connected to a battery cluster 101, and is used to detect the amount of gas in the cooling medium in each battery cluster 101. When the amount of 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 is forced to switch from the normal operating mode to the degassing mode. When the amount of gas in the cooling medium exceeds the first preset value, it indicates that the energy storage system has a high probability of bubble bridges causing bubble breakdown. At this time, the normal operating mode may cause the entire energy storage system to be abnormal. Based on this, a control signal is sent to the battery management system, so that the battery management system can control the operation of the energy storage system. By detecting each battery cluster 101 through the first detection device 103, it can facilitate the switching of the energy storage system between different operating modes, further improving the reliability of the energy storage system.

[0054] In some embodiments, the first detection device 103 is also used to: when it is detected that the amount of the gas in the cooling medium exceeds the second preset value, output a judgment signal to the battery management system, the battery management system determines whether the energy storage system meets the preset conditions, and when the energy storage system meets the preset conditions, 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 conditions include: the duration of the energy storage 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 a degassing mode. When the amount of the gas in the cooling medium exceeds the second preset value, it indicates that the cooling medium already contains a lot of gas, there are certain safety hazards, 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 conditions, the energy storage system is controlled to switch to the degassing mode. When the energy storage system does not meet the preset conditions, it continues to detect and switches to the degassing mode after the energy storage system meets the preset conditions.

[0055] In some embodiments, the degassing device 102 removes the gas of the cooling medium in a battery cluster 101 and then connects to another battery cluster 101. The energy storage system also includes: a second detection device 104, which is connected to the degassing device 102 and is used to detect the amount of gas separated from the cooling medium per unit volume in the degassing device 102, and control the connection time between the degassing device 102 and the currently connected battery cluster 101 according to the amount of separated gas, wherein the amount of 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 that it is easy to allocate the time for the degassing mode to process each battery cluster 101, so that the gas content in the cooling medium after the degassing mode can be further reduced, and the reliability of the energy storage system can be improved.

[0056] In some embodiments, the energy storage system further includes: a temperature monitoring device (not shown), which is used to detect the temperature in each battery cluster 101 in 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, the abnormality caused by the excessive temperature of the battery cluster 101 is avoided, so as to improve the reliability of the energy storage system.

[0057] In some embodiments, in the degassing mode, each battery cluster 101 is degassed in turn. At this time, the cooling medium in the battery cluster 101 that has not been degassed is circulated 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 abnormal situations caused by excessive temperature of the battery cluster 101 in the degassing mode.

[0058] In the normal operation mode of the embodiment of the present disclosure, the cooling medium circulates back and forth in the liquid cooling unit 100 and the battery cluster 101 to reduce the temperature in the battery cluster 101. After the battery cluster 101 has been running for a period of time, some air will dissolve in the cooling medium, resulting in reduced 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 gas in the cooling medium is removed by the degassing device 102, thereby improving the reliability of the energy storage system.

[0059] Another embodiment of the present disclosure further provides a cooling cycle method, which can be implemented by the energy storage system in some or all of the above-mentioned embodiments. The cooling cycle method provided by another embodiment of the present disclosure will be described below. It should be noted that the same or corresponding parts of the above-mentioned embodiments can refer to the corresponding description of the above-mentioned embodiments and will not be repeated below.

[0060] refer to Figure 3 , Figure 3 A flow chart of a cooling cycle method provided in one embodiment of the present disclosure.

[0061] In some embodiments, a cooling cycle method for an energy storage system may include: Step S10: determining whether the energy storage system is in a charging or discharging state.

[0062] Step S11: If the energy storage system is not in a charge and discharge state, a degassing process is performed, and the degassing process includes: controlling the battery cluster in the energy storage system to be connected to the 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 cluster to be disconnected from the degassing device and controlling the battery cluster to be connected to the cooling unit.

[0063] By judging whether the energy storage system is in a charge and discharge state, it is determined whether the cooling medium in the battery cluster can be degassed, which can avoid affecting the normal operation of the energy storage system and avoiding temporary power outages of the energy storage system. When the energy storage system is not in a charge and discharge state, the cooling medium can be degassed through a degassing device, thereby increasing the reliability of the energy storage system.

[0064] In some embodiments, there are multiple battery clusters in the energy storage system, and the degassing process includes: sequentially controlling each battery cluster to be connected to the degassing device to sequentially remove the gas dissolved in the cooling medium in each battery cluster. In other words, during the degassing process, the degassing process is completed one battery cluster at a time, thereby avoiding mixing of the cooling medium after the degassing process with the cooling medium that has not been degassed, thereby avoiding reducing the degassing efficiency of the entire degassing process.

[0065] That is, when the gas dissolved in the cooling medium in any one of the battery clusters is removed, the remaining battery clusters are disconnected from the battery cluster in the degassing process.

[0066] In other embodiments, multiple battery clusters may be degassed simultaneously.

[0067] In some embodiments, before the degassing treatment is performed, it also includes: judging the time from the energy storage system to the next charge and discharge state, if the time from the energy storage system to the next charge and discharge state is greater than the first preset time, controlling the battery cluster in the energy storage system to be connected to the degassing device; wherein the first preset time is the time required to remove the gas dissolved in all cooling media in the energy storage system. In other words, when the energy storage system can complete the removal of the gas in the cooling medium in all battery clusters before the next charge and discharge state, the degassing treatment is performed to remove all the gas in the cooling medium in all battery clusters in one degassing treatment. By removing the gas in the cooling medium in all battery clusters at one time, the percentage of gas removal can be increased, thereby improving the efficiency and effect of the degassing treatment.

[0068] In some embodiments, 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 battery cluster 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 battery cluster, the gas dissolved in the cooling medium in N battery clusters is removed, where N is 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 battery cluster, rounded. In other words, a degassing process does not need to remove all battery clusters, but only removes the gas dissolved in the cooling medium in a few battery clusters. In this way, in 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 gas content in the cooling medium in each battery cluster will be reduced, thereby improving the reliability of the energy storage system.

[0069] In some embodiments, before removing the gas dissolved in the cooling medium in N clusters of battery clusters, the method also includes: obtaining information of the battery cluster that completed the last degassing treatment, if the last degassing treatment removed the gas dissolved in the cooling medium in all energy storage systems, then this degassing treatment will sequentially treat the gas dissolved in the cooling medium in the battery cluster; if the last degassing treatment removed the gas dissolved in the cooling medium in some energy storage systems, then this degassing treatment will sequentially treat the gas dissolved in the cooling medium in the battery cluster that has not undergone the last degassing treatment. That is to say, before the degassing treatment is performed, the process of the last degassing treatment is first detected. If the last degassing treatment has completed the degassing of the cooling medium in all the battery clusters, then this degassing treatment can remove the gas contained in the cooling medium in any battery cluster. If the last degassing treatment did not complete the degassing of all the battery clusters, then this degassing treatment is selected from the battery clusters that have not been degassed last time, so that when the time from the energy storage system to the next time being in the charging and discharging state 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 in a certain battery cluster not being degassed for a long time, avoiding abnormalities in any battery cluster, and thus improving the reliability of the energy storage system.

[0070] In some embodiments, before the degassing treatment is performed, it also includes: judging the time that the energy storage system is in the normal operating mode, if the time that the energy storage system is in the normal operating mode is greater than the second preset time, then controlling the battery cluster in the energy storage system to be connected to the degassing device; if the time that the energy storage system is in the normal operating mode is less than the second preset time, controlling the battery cluster to remain disconnected from the degassing device; wherein, the energy storage system is in the normal operating mode means: the energy storage system is started, but is not in the charging and discharging state, and the cooling medium circulates in the battery cluster and the liquid cooling unit. When the energy storage system is in the normal operating mode for a period of time greater than the second preset time, it indicates that the energy storage system has been working for a period of time, which will inevitably cause a certain amount of bubbles in the cooling medium in the battery cluster, and degassing treatment is required to improve the reliability of the energy storage system. Moreover, by judging whether the time that the energy storage system is in the normal operating mode is greater than the second preset time, it can also be avoided that the degassing treatment affects the normal working time of the energy storage system.

[0071] The following is a specific example to illustrate the cooling cycle method provided by the embodiment of the present disclosure. When the system operates 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, and the passage between the degassing device and the battery cluster is disconnected. It is determined whether the energy storage system is in a charging and discharging state, whether the time the energy storage system has been in a normal operating mode is greater than a second preset time, and whether the time from the energy storage system to the next charging and discharging state 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 open, and each battery cluster is controlled to be connected to the degassing device in turn, so as to degas the cooling medium in each battery cluster in turn.

[0072] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail 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, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in 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 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, 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, 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; A battery management system, the battery management system is used 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, during which the cooling medium passes through the degassing device, and the degassing device works to remove gas in the cooling medium passing through the degassing device; Among them, the preset conditions are: the energy storage system is not in a charging or discharging state, and the time length of the energy storage system in the normal operating mode is greater than or equal to a preset time length, and / or the time difference between the current time and the next charging or discharging time is greater than the total time of a degassing mode.

2. The energy storage system according to claim 1, 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.

3. The energy storage system according to claim 1, characterized in that: Also includes: 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, and when the amount of the gas substance in the cooling medium exceeds a first preset value, a control signal is output to the battery management system, and the battery management system is forced to switch from the normal operating mode to the degassing mode.

4. The energy storage system according to claim 3, 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; The second preset value is smaller than the first preset value.

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 charging or discharging state, and the duration of the energy storage system in the normal operating mode is greater than a second preset duration, and / or the time difference between the current time and the next charging or discharging time is greater than the first preset duration, a degassing process is performed, and the degassing process includes: controlling the battery cluster 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 charging and discharging state, the battery cluster is controlled to be disconnected from the degassing device, and the battery cluster is controlled to be connected to the 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: The first preset time is the time required to remove the gas dissolved in all cooling media 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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