Thermal runaway control method, battery pack and energy storage system

Abstract

The present application relates to a thermal runaway control method, a battery pack and an energy storage system. The method includes: in the case of thermal runaway of the battery pack, connecting the box body of the battery pack to the thermal runaway circulation loop and disconnecting the connection between the box body of the battery pack and the liquid cooling circulation loop; wherein the thermal runaway circulation loop is used for circulating the coolant in the box body of the battery pack with thermal runaway; and the liquid cooling circulation loop is used for circulating the coolant of the battery pack operating normally. By using this method, coolant contamination can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and particularly to a thermal runaway control method, a battery pack, and an energy storage system. Background Art

[0002] An energy storage system is equipped with battery cells. During the charge and discharge 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. Therefore, an external cooling system must be provided.

[0003] 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. In addition, in the immersion energy storage technology, the structure of the battery pack can be cancelled, and the battery cells can be directly arranged in the battery cluster in a multi-layer form to achieve the purpose of improving the system integration, simplifying the structure, and reducing the cost.

[0004] In traditional technologies, the immersion PACK-level liquid cooling scheme generally fills the PACK with coolant and realizes the material and energy exchange with the liquid cooling circulation system through the nozzles on the PACK; or fills the PACK with coolant and arranges a cold plate at the bottom of the PACK. The coolant in the PACK does not flow, and there are nozzles on the cold plate. The material and energy exchange is carried out between the nozzles and the liquid cooling circulation system, and then the material and energy exchange is carried out between the cold plate and the coolant to cool the battery cells.

[0005] However, in the immersion PACK-level liquid cooling scheme of traditional technologies, all the battery cells are in a liquid cooling circulation loop. If a single battery cell has a thermal runaway, a large amount of waste gas, battery liquid, and solid debris dissolved in the coolant released by the thermal runaway of the battery cell will contaminate all the coolant in the entire system, resulting in waste of the coolant. Summary of the Invention

[0006] Based on this, in view of the above technical problems, it is necessary to provide a thermal runaway control method, a battery pack, and an energy storage system that can avoid coolant contamination.

[0007] In a first aspect, the present application provides a thermal runaway control method, and the method includes:

[0008] In the case of thermal runaway of the battery pack, connect the housing of the battery pack to the thermal runaway circulation loop and disconnect the connection between the housing of the battery pack and the liquid cooling circulation loop; wherein the thermal runaway circulation loop is used for the circulation of the coolant in the housing of the battery pack with thermal runaway; and the liquid cooling circulation loop is used for the circulation of the coolant of the battery pack operating normally.

[0009] In one alternative embodiment, the method further includes:

[0010] In the case of thermal runaway of the battery pack, connect the liquid cooling plate of the battery pack to the liquid cooling circulation loop.

[0011] In one alternative embodiment, the method further includes:

[0012] Obtain the first battery pack operation information collected by each thermal runaway sensor, and predict whether the battery pack has a thermal runaway based on the first battery pack operation information;

[0013] In the case of predicting that the battery pack is about to have a thermal runaway, connect the housing of the battery pack to the thermal runaway circulation loop and disconnect the connection between the housing of the battery pack and the liquid cooling circulation loop.

[0014] In one alternative embodiment, the method further includes:

[0015] After the housing of the battery pack is connected to the thermal runaway circulation loop, obtain the second battery pack operation information collected by each of the thermal runaway sensors;

[0016] In the case of determining that the battery pack has not had a thermal runaway based on the second battery pack operation information, detect whether only one battery pack is connected to the thermal runaway circulation loop;

[0017] In the case where only one battery pack is connected to the thermal runaway circulation loop or multiple battery packs are connected to the thermal runaway circulation loop and none of the multiple battery packs has a thermal runaway, disconnect the housing of the battery pack that has not had a thermal runaway from the thermal runaway circulation loop, and connect at least one of the liquid cooling plate and the housing of the battery pack that has not had a thermal runaway to the liquid cooling circulation loop;

[0018] In the case where multiple battery packs are connected to the thermal runaway circulation loop and at least one of the multiple battery packs has a thermal runaway, after the contaminated coolant in the battery packs that have not had a thermal runaway is discharged, disconnect the housing of the battery packs that have not had a thermal runaway from the thermal runaway circulation loop, and connect at least one of the liquid cooling plate and the housing of the battery packs that have not had a thermal runaway to the liquid cooling circulation loop.

[0019] In one alternative embodiment, predicting whether the battery pack undergoes thermal runaway based on the first battery pack operation information is performed by a pre-trained prediction model;

[0020] The method further includes:

[0021] When it is determined based on the second battery pack operation information that the battery pack does not undergo thermal runaway, storing the first battery pack operation information;

[0022] When the quantity of the first battery pack operation information is greater than a first quantity threshold, updating the prediction model based on the stored first battery pack operation information.

[0023] In one alternative embodiment, the method further includes:

[0024] When the quantity of the battery packs predicted to undergo thermal runaway based on the first battery pack operation information is greater than a second quantity threshold, simultaneously sending valve control signals corresponding to each battery pack predicted to undergo thermal runaway, where the control signals are used to control the valves to connect the box body of the battery pack to the thermal runaway circulation loop and disconnect the connection between the box body of the battery pack and the liquid cooling circulation loop.

[0025] In one alternative embodiment, the method further includes:

[0026] When the battery pack does not undergo thermal runaway, connecting at least one of the liquid cooling plate and the box body of the battery pack to the liquid cooling circulation loop.

[0027] In a second aspect, the present application further provides a battery pack, where the battery pack includes:

[0028] A box body, which is internally provided with an accommodation space for accommodating a coolant, and the box body is provided with a first liquid inlet and a first liquid outlet;

[0029] Electric cores, which are arranged in the accommodation space;

[0030] A thermal runaway sensor, which is used to collect battery pack operation information;

[0031] The first liquid inlet, the thermal runaway circulation loop, and the liquid cooling circulation loop are respectively connected to a first three-way valve, and the first liquid outlet, the thermal runaway circulation loop, and the liquid cooling circulation loop are respectively connected to a second three-way valve;

[0032] When it is determined based on the battery pack operation information that the battery pack undergoes thermal runaway, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop.

[0033] In one alternative embodiment, the battery pack further includes:

[0034] A liquid cooling plate adjacent to the box body, the liquid cooling plate is used to accommodate a coolant, and the liquid cooling plate is provided with a second liquid inlet and a second liquid outlet;

[0035] The first three-way valve is connected to the liquid cooling circulation loop through a third three-way valve, and the other end of the third three-way valve is connected to the second liquid inlet; the second three-way valve is connected to the liquid cooling circulation loop through a fourth three-way valve, and the other end of the fourth three-way valve is connected to the second liquid outlet;

[0036] In the case of thermal runaway of the battery pack, the third three-way valve and the fourth three-way valve connect the liquid cooling plate to the liquid cooling circulation loop and disconnect the connection between the box body of the battery pack and the liquid cooling circulation loop.

[0037] In a third aspect, the present application further provides an energy storage system, which includes:

[0038] At least two battery packs;

[0039] A liquid cooling unit for controlling the temperature of the coolant and driving the circulation of the coolant;

[0040] A liquid cooling circulation loop, through which the at least two battery packs are connected to the liquid cooling unit;

[0041] A thermal runaway circulation loop for circulating the coolant in the box body of the battery pack in thermal runaway;

[0042] A controller for executing the thermal runaway control method described in any of the above embodiments.

[0043] In the case of thermal runaway of the battery pack, the above thermal runaway control method, battery pack and energy storage system connect the box body of the battery pack to the thermal runaway circulation loop and disconnect the connection between the box body of the battery pack and the liquid cooling circulation loop. This can prevent the coolant in the box body of the battery pack in thermal runaway from circulating into the liquid cooling circulation loop during thermal runaway, thereby preventing the contaminated coolant from flowing into the box body of the battery pack that has not experienced thermal runaway and avoiding the waste of coolant caused by coolant contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for describing the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0045] Figure 1 Schematic diagram of a battery pack in an embodiment;

[0046] Figure 2 Schematic diagram of the states of each three-way valve and the loop connection mode in the case of thermal runaway in an embodiment;

[0047] Figure 3 Flow chart of the post - thermal - runaway treatment steps in an embodiment;

[0048] Figure 4 Schematic diagram of temperature control using coolant in a single mode in an embodiment;

[0049] Figure 5 Schematic diagram of temperature control in a parallel mode in an embodiment;

[0050] Figure 6 Flow chart of the control logic of a battery pack in an embodiment;

[0051] Figure 7 Schematic diagram of an energy storage system in an embodiment;

[0052] Figure 8 Flow chart of a thermal - runaway control method in an embodiment. Detailed implementation manners

[0053] In order to make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0054] The embodiments of the present application provide a battery pack, specifically in combination with Figure 1 as shown, Figure 1 Schematic diagram of a battery pack in an embodiment. The battery pack includes a box body, battery cells, a thermal - runaway sensor, a first three - way valve, and a second three - way valve.

[0055] Wherein, an accommodation space is provided inside the box body for accommodating coolant, and the box body is provided with a first liquid inlet and a first liquid outlet. The battery cells are arranged in the accommodation space. The thermal - runaway sensor is arranged in the accommodation space for collecting the operation information of the battery pack. The first liquid inlet, the thermal - runaway circulation loop, and the liquid - cooling circulation loop are respectively connected to the first three - way valve, and the first liquid outlet, the thermal - runaway circulation loop, and the liquid - cooling circulation loop are respectively connected to the second three - way valve.

[0056] Among them, the first three - way valve and the second three - way valve can be solenoid valves, and the opening and closing of the solenoid valves are controlled by a controller to connect the box body with the corresponding loop.

[0057] In this way, when the controller determines that a thermal runaway of the battery pack occurs based on the operating information of the battery pack, the first three-way valve and the second three-way valve are controlled to connect the box body to the thermal runaway circulation loop and disconnect the box body from the liquid cooling circulation loop. Thereby, it is possible to prevent the contaminated coolant from flowing into the box body of the battery pack that has not experienced thermal runaway, and avoid the waste of coolant caused by coolant contamination.

[0058] It should be noted that the present application does not limit the manner in which the controller determines that a thermal runaway of the battery pack occurs based on the operating information of the battery pack. However, for clarity, an embodiment is given. The thermal runaway sensor can include various types of sensors, such as a temperature sensor and a corresponding gas sensor. In the case of a thermal runaway, the temperature of the battery pack will increase abnormally, and the gas sensor will detect the corresponding gas. Generally, when a thermal runaway occurs, the temperature of the battery pack changes first. Therefore, in the present application, it can be determined that a thermal runaway of the battery pack occurs when the temperature sensor detects an abnormal temperature change or the temperature is higher than the thermal runaway temperature threshold, or when the temperature detected by the temperature sensor is higher than the thermal runaway temperature threshold and the concentration of the corresponding gas detected by the gas sensor is greater than the concentration threshold.

[0059] In the case of a thermal runaway, the battery pack will leak, causing some substances to enter the coolant in the box body, resulting in coolant contamination. To prevent the contaminated coolant from entering the liquid cooling circulation loop and expanding the scope of coolant contamination, in the present application, when it is determined that a thermal runaway of the battery pack occurs, the box body is connected to the thermal runaway circulation loop and disconnected from the liquid cooling circulation loop.

[0060] Optionally, in the present application, when it is determined that a thermal runaway of the battery pack occurs, the connection between the box body and the liquid cooling circulation loop can be disconnected first, and then the box body can be connected to the thermal runaway circulation loop later. In other embodiments, when it is determined that a thermal runaway of the battery pack occurs, the box body can be connected to the thermal runaway circulation loop while disconnecting the connection between the box body and the liquid cooling circulation loop. No specific limitation is made here, and it is only necessary to ensure that the contaminated coolant cannot flow back to the liquid cooling circulation loop when it is determined that a thermal runaway of the battery pack occurs.

[0061] Continuing with Figure 1 As shown, in one optional embodiment, the battery pack further includes a liquid cooling plate adjacent to the box body. The liquid cooling plate is used to accommodate coolant, and the liquid cooling plate is provided with a second liquid inlet and a second liquid outlet.

[0062] The first three-way valve is connected to the liquid cooling circulation loop through the third three-way valve, and the other end of the third three-way valve is connected to the second liquid inlet; the second three-way valve is connected to the liquid cooling circulation loop through the fourth three-way valve, and the other end of the fourth three-way valve is connected to the second liquid outlet.

[0063] Wherein, in the case of thermal runaway of the battery pack, the third three-way valve and the fourth three-way valve connect the liquid cooling plate to the liquid cooling circulation loop, and disconnect the connection between the box body of the battery pack and the liquid cooling circulation loop.

[0064] In this way, in the case of thermal runaway of the battery pack, in order to prevent the thermal runaway from developing more severely, the battery pack is also cooled by the liquid cooling plate so that the thermal runaway is within a controllable range. Figure 2 The states of each three-way valve and the loop connection mode in the case of thermal runaway are shown.

[0065] In some alternative embodiments, in order to prevent the coolant in the case of thermal runaway from entering the liquid cooling circulation loop and to predict thermal runaway, when it is determined based on the first battery pack operation information collected by the thermal runaway sensor that the battery pack is about to experience thermal runaway, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop.

[0066] The method for determining that the battery pack is about to experience thermal runaway based on the first battery pack operation information may include any one of the following: by detecting whether the temperature in the first battery pack operation information has mutated, and if the temperature has mutated, it is determined that the battery pack is about to experience thermal runaway; by processing the first battery pack operation information with a pre-trained prediction model to determine whether thermal runaway is about to occur.

[0067] Among them, since thermal runaway is generally accompanied by a sudden change in temperature before it occurs, and leakage will occur only after the temperature mutation, it is possible to first predict whether thermal runaway is about to occur based on whether the temperature has mutated.

[0068] The pre-trained prediction model can be obtained by training based on the historical battery pack operation information collected before thermal runaway occurred in history. This prediction model can adopt neural networks, etc., and no specific limitation is made here.

[0069] In one of the alternative embodiments, predicting whether the battery pack has experienced thermal runaway based on the first battery pack operation information is performed by a pre-trained prediction model; the method further includes: storing the first battery pack operation information when it is determined based on the second battery pack operation information that the battery pack has not experienced thermal runaway; and updating the prediction model based on the stored first battery pack operation information when the quantity of the first battery pack operation information is greater than the first quantity threshold.

[0070] In order to improve the prediction accuracy, the prediction model is updated in this application. When the prediction model predicts that thermal runaway will occur, but it is actually determined based on the operating information of the second battery pack that the battery pack has not experienced thermal runaway, the operating information of the first battery pack can be stored. The stored operating information of the first battery pack can be used to update the prediction model. To avoid the cost problem caused by frequent updates of the prediction model, the prediction model will only be updated when the quantity of the operating information of the first battery pack is greater than the first quantity threshold. This not only balances the cost but also improves the accuracy of the prediction model.

[0071] In some alternative embodiments, to improve the accuracy, this application may determine that the battery pack is about to experience thermal runaway only when it is determined based on the temperature that the battery pack is about to experience thermal runaway and when it is determined based on the prediction model that the battery pack is about to experience thermal runaway. Or, to improve the sensitivity of the system, as long as it is determined based on the temperature that the battery pack is about to experience thermal runaway or it is determined based on the prediction model that the battery pack is about to experience thermal runaway, it is determined that the battery pack is about to experience thermal runaway. No specific limitation is made here.

[0072] Among them, in this application, thermal runaway is predicted before it occurs. When it is determined that thermal runaway is about to occur or when thermal runaway occurs, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop, thus preventing the expansion of the coolant pollution area.

[0073] In addition, the control mode can be determined in advance in this application, that is, whether it is the prediction mode. If the prediction mode is selected, when it is determined that thermal runaway is about to occur, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop; otherwise, after thermal runaway occurs, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop.

[0074] In some alternative embodiments, the battery pack further includes an exhaust valve located on the box body. The exhaust valve is used to discharge the gas generated by thermal runaway in the case of thermal runaway of the battery pack. On the one hand, the box body is connected to the thermal runaway loop to discharge the contaminated coolant in the box body, and on the other hand, the gas generated by thermal runaway is discharged through the exhaust valve.

[0075] In some alternative embodiments, after the box body of the battery pack is connected to the thermal runaway circulation loop, when it is determined based on the second battery pack operation information collected by each thermal runaway sensor that the battery pack has not experienced thermal runaway, and the thermal runaway circulation loop is connected to only one battery pack or the thermal runaway circulation loop is connected to multiple battery packs and none of the multiple battery packs has experienced thermal runaway, the first three-way valve and the second three-way valve of the battery pack that has not experienced thermal runaway disconnect the box body from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery pack that has not experienced thermal runaway connect at least one of the liquid cooling plate and the box body to the liquid cooling circulation loop. When it is determined based on the second battery pack operation information collected by each thermal runaway sensor that the battery pack has not experienced thermal runaway, the thermal runaway circulation loop is connected to multiple battery packs, and at least one of the multiple battery packs has experienced thermal runaway, after the contaminated coolant in the battery packs that have not experienced thermal runaway is discharged, the first three-way valve and the second three-way valve of the battery packs that have not experienced thermal runaway disconnect the box body from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery packs that have not experienced thermal runaway connect at least one of the liquid cooling plate and the box body to the liquid cooling circulation loop.

[0076] For the sake of easy understanding, in combination with Figure 3 as shown Figure 3 is a flowchart of the post-thermal runaway processing steps in an embodiment. In this embodiment, based on the first battery pack operation information, it is predicted that the battery pack is about to experience thermal runaway. Therefore, the first three-way valve and the second three-way valve connect the box body to the thermal runaway circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop.

[0077] Subsequently, the thermal runaway sensor continues to collect the second battery pack operation information of the battery pack. If it is determined based on the second battery pack operation information that the battery pack has not ultimately experienced thermal runaway, the battery pack needs to be reconnected so that the energy storage system can operate normally.

[0078] Among them, since the battery pack is connected to the thermal runaway circulation loop, if there are other battery packs that have experienced thermal runaway, the coolant in the box body of the battery pack that has not experienced thermal runaway but is connected to the thermal runaway circulation loop has also been contaminated; if there are no other battery packs that have experienced thermal runaway, it is considered that the coolant in the box body of the battery pack has not been contaminated. Therefore:

[0079] The first case: When only one battery pack is connected to the thermal runaway circulation loop or multiple battery packs are connected to the thermal runaway circulation loop and none of the multiple battery packs has experienced thermal runaway, at this time, the coolant in the box of each battery pack is not contaminated. Therefore, the first three-way valve and the second three-way valve of the battery packs that have not experienced thermal runaway disconnect the box from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery packs that have not experienced thermal runaway connect at least one of the liquid cooling plate and the box to the liquid cooling circulation loop.

[0080] The second case: Based on the second battery pack operation information collected by each thermal runaway sensor, it is determined that the battery pack has not experienced thermal runaway. When the thermal runaway circulation loop is connected to multiple battery packs and at least one of the multiple battery packs has experienced thermal runaway, after the contaminated coolant in the battery packs that have not experienced thermal runaway is discharged, the first three-way valve and the second three-way valve of the battery packs that have not experienced thermal runaway disconnect the box from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery packs that have not experienced thermal runaway connect at least one of the liquid cooling plate and the box to the liquid cooling circulation loop.

[0081] In the above two cases, if the coolant in the box of the battery pack is not contaminated, the battery pack is directly reconnected to the liquid cooling circulation loop through valve control to operate normally. If the coolant in the box of the battery pack is contaminated, the coolant in the battery pack box needs to be emptied and then reconnected.

[0082] When reconnecting the battery pack to the liquid cooling circulation loop, it is necessary to determine the cooling mode, that is, the parallel mode or the single mode. The parallel mode includes parallel liquid cooling plate cooling and box cooling. The single mode only includes liquid cooling plate cooling or only includes box cooling. For the specific limitations of the parallel mode and the single mode, refer to the following text.

[0083] In some alternative embodiments, the first three-way valve and the second three-way valve of each battery pack about to experience thermal runaway receive valve control signals in parallel. The control signals are used to control the first three-way valve and the second three-way valve to connect the box of the battery pack to the thermal runaway circulation loop and disconnect the connection between the box of the battery pack and the liquid cooling circulation loop. In this application, in order to improve the control efficiency, when the number of battery packs about to experience thermal runaway is greater than the number threshold, the first three-way valve and the second three-way valve are controlled in parallel to prevent contaminated coolant from entering the liquid cooling circulation loop due to the delay of the valve control signal.

[0084] The parallel connection here includes the parallel connection of each battery pack that is about to experience thermal runaway, and may also include the parallel connection of the first three-way valve and the second three-way valve in each battery pack that is about to experience thermal runaway. The controller can be a distributed controller, and each controller can be assigned to control the valves of a corresponding number of battery packs, so as to realize the sending of parallel valve control signals and improve the control efficiency.

[0085] In some alternative embodiments, when the battery pack does not experience thermal runaway, the first three-way valve and the second three-way valve disconnect the box body from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve connect at least one of the liquid cooling plate and the box body to the liquid cooling circulation loop.

[0086] In this application, the above parallel mode and single mode are realized by controlling the valves. The valves are controlled based on temperature and the rate of temperature rise.

[0087] In some alternative embodiments, the battery pack further includes a temperature sensor for collecting the temperature of the battery pack. The number of the temperature sensors is at least one. To improve the accuracy of the temperature collected by the temperature sensors, the positions of the at least one temperature sensor can include the surface of the battery cell, so that the temperature of the battery cell can be accurately collected. This is also because the temperature of the battery cell will mutate first during thermal runaway. In some alternative embodiments, the temperature sensors on the surface of the battery cells should be evenly arranged to obtain the temperature of each battery cell more accurately. In other alternative embodiments, some temperature sensors can also be set at a certain distance from the battery cells on the box body of the battery pack to facilitate understanding the temperature changes at various positions inside the box body. When judging thermal runaway or selecting a cooling mode, the temperatures collected by each temperature sensor can be screened to obtain the temperature of the battery pack. For example, the highest temperature among the temperatures collected by each temperature sensor can be selected as the temperature of the battery pack, and then judgment can be made to improve the response speed of the system.

[0088] In some alternative embodiments, when the thermal runaway sensor does not detect thermal runaway of the battery pack and the temperature of the battery pack detected by the temperature sensor is less than the temperature threshold, the first three-way valve and the second three-way valve disconnect the box body from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve connect the box body or the liquid cooling plate to the liquid cooling circulation loop.

[0089] In one optional embodiment, when the thermal runaway sensor does not detect thermal runaway of the battery pack and the temperature of the battery pack detected by the temperature sensor is greater than or equal to the temperature threshold, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve are used to connect the liquid cooling plate to the liquid cooling circulation loop and connect the box body to the liquid cooling circulation loop.

[0090] Wherein, when the temperature is less than the temperature threshold, the present application cools the battery pack in a single mode, that is, cools the battery pack only through the coolant in the liquid cooling plate or only through the coolant in the box body.

[0091] When the temperature is greater than or equal to the temperature threshold, the present application cools the battery pack in a parallel mode, that is, cools the battery pack through the coolant in the liquid cooling plate and the coolant in the box body.

[0092] Specifically, as shown in Figure 4 and Figure 5 , wherein Figure 4 is a schematic diagram of temperature control using coolant in a single mode in an embodiment; Figure 5 is a schematic diagram of temperature control in a parallel mode in an embodiment. In Figure 4 , when it is detected that the temperature of the battery pack is lower than the temperature threshold, the battery pack is cooled only through the coolant in the liquid cooling plate. At this time, only the liquid cooling plate is connected to the liquid cooling circulation loop, avoiding the circulation of excess coolant while achieving cooling. In Figure 5 , when it is detected that the temperature of the battery pack is greater than or equal to the temperature threshold, the battery pack is cooled through the coolant in the liquid cooling plate and the coolant in the box body, that is, the third three-way valve and the fourth three-way valve are fully opened, and the first three-way valve and the second three-way valve close the passage between the box body of the battery pack and the thermal runaway circulation loop. At this time, the liquid cooling plate is in parallel with the box body of the battery pack, and the coolant flows in the box body of the battery pack and the liquid cooling plate, realizing direct convective heat transfer between the coolant of the battery pack and the battery cells and indirect heat transfer of the liquid cooling plate, improving the heat transfer efficiency.

[0093] In one optional embodiment, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve are used to connect the liquid cooling plate to the liquid cooling circulation loop and disconnect the connection between the box body and the liquid cooling circulation loop when the temperature rise rate of the battery pack is less than the rate threshold; when the temperature rise rate of the battery pack is greater than or equal to the rate threshold, disconnect the connection between the liquid cooling plate and the liquid cooling circulation loop and connect the box body to the liquid cooling circulation loop.

[0094] Among them, the present application also determines the heat exchange method in a single mode based on the heating rate. That is, when the heating rate is less than the rate threshold, only the liquid cooling plate is connected to the liquid cooling circulation loop, and the connection between the box body and the liquid cooling circulation loop is disconnected, that is, indirect heat exchange by the liquid cooling plate can be achieved.

[0095] When the heating rate is greater than or equal to the rate threshold, the connection between the liquid cooling plate and the liquid cooling circulation loop is disconnected, and the box body is connected to the liquid cooling circulation loop. That is, the liquid cooling plate flows in the box body of the battery pack to realize direct convective heat exchange between the coolant of the battery pack and the battery cells, improving the heat exchange efficiency.

[0096] For easy understanding, in combination with Figure 6 as shown in Figure 6 is a flowchart of the control logic of the battery pack in an embodiment. In this embodiment, the first operation information of each battery pack is collected by a thermal runaway sensor. When it is determined based on the first operation information that the nth battery pack has a thermal runaway or is about to have a thermal runaway, the three-way valve of the thermal runaway circulation loop where the nth battery pack is located is opened, so that the nth battery pack is connected to the thermal runaway circulation loop, and the connection between the box body of the nth battery pack and the liquid cooling circulation loop is disconnected. And after the nth battery pack is connected to the thermal runaway circulation loop, the water pump of the thermal runaway circulation loop is turned on.

[0097] When it is determined based on the first operation information that the battery pack has not had a thermal runaway, the temperature of each battery pack is obtained. If the temperature is greater than the temperature threshold, the parallel mode is used for heat exchange. If the temperature is less than the temperature threshold, the heating rate is obtained. When the heating rate is greater than or equal to the rate threshold, the connection between the liquid cooling plate and the liquid cooling circulation loop is disconnected, and the box body is connected to the liquid cooling circulation loop; when the heating rate is less than the rate threshold, the connection between the liquid cooling plate and the liquid cooling circulation loop is connected, and the box body and the liquid cooling circulation loop are opened.

[0098] In the above embodiment, different heat exchange modes are selected based on the temperature and the heating rate, which can improve the heat exchange efficiency and achieve the purpose of cost saving.

[0099] In combination with Figure 7 as shown in, the present application also provides an energy storage system, which includes at least two battery packs, a liquid cooling unit, a liquid cooling circulation loop and a thermal runaway circulation loop. The liquid cooling unit is used to control the temperature of the coolant and drive the circulation of the coolant. At least two battery packs are connected to the liquid cooling unit through the liquid cooling circulation loop. The thermal runaway circulation loop is used for the circulation of the coolant in the box body of the battery pack with thermal runaway. A controller is used to execute the thermal runaway control method to select different heat exchange modes.

[0100] The battery pack is connected in series or in parallel with other battery packs through a liquid cooling circulation loop and is connected to the liquid cooling unit, so that the coolant after temperature control flowing through the liquid cooling unit can exchange substances with the coolant in the battery pack to achieve temperature control.

[0101] The liquid cooling unit includes components such as a temperature sensor, a refrigeration cycle heat exchange unit, a heating unit, and a water pump. The temperature sensor in the liquid cooling unit can monitor the temperature of the coolant at the inlet and outlet of the liquid cooling unit. The refrigeration cycle heat exchange unit uses a fan to exchange heat between air and the coolant, and then the heat-exchanged coolant circulates to cool the battery cells. The water pump is used to drive the coolant to flow in the liquid cooling circulation loop. The heating unit is used to raise the temperature of the coolant for functions such as preheating the battery pack, and specific limitations are not described here.

[0102] In one optional embodiment, the liquid cooling circulation loop is used to circulate the coolant in the liquid cooling unit, the coolant in the coolant circulation loop, and the coolant in the cooling plate of the battery pack; or the liquid cooling circulation loop is used to circulate the coolant in the liquid cooling unit, the coolant in the coolant circulation loop, and the coolant in the casing of the battery pack; or the liquid cooling circulation loop is used to circulate the coolant in the liquid cooling unit, the coolant in the coolant circulation loop, the coolant in the cooling plate of the battery pack, and the coolant in the casing of the battery pack.

[0103] In one optional embodiment, the thermal runaway circulation loop is used to circulate the coolant in the casing of the battery pack in thermal runaway and the coolant in the thermal runaway circulation loop.

[0104] Optionally, the above energy storage system further includes an expansion tank. The function of the expansion tank is to avoid overpressure caused by high temperature during thermal runaway. The water pump is used to drive the flow of the coolant in the thermal runaway circulation loop to avoid excessive local temperature of the battery pack. Each battery pack is connected to the loop in series or in parallel through a plurality of electromagnetic three-way valves, and the electromagnetic three-way valve in the thermal runaway circulation loop remains closed under normal operating conditions.

[0105] In an exemplary embodiment, as Figure 8 shown, a thermal runaway control method is provided. Taking the method applied to the Figure 7 controller as an example, the method includes the following steps. Among them:

[0106] S802: In the case of thermal runaway of the battery pack, connect the casing of the battery pack to the thermal runaway circulation loop and disconnect the connection between the casing of the battery pack and the liquid cooling circulation loop; the thermal runaway circulation loop is used for the circulation of the coolant in the casing of the battery pack in thermal runaway; the liquid cooling circulation loop is used for the circulation of the coolant of the battery pack in normal operation.

[0107] In one alternative embodiment, the method further includes: when a thermal runaway occurs in the battery pack, connecting the liquid cooling plate of the battery pack to the liquid cooling circulation loop.

[0108] In one alternative embodiment, the method further includes: obtaining first battery pack operation information collected by each thermal runaway sensor, and predicting whether a thermal runaway occurs in the battery pack based on the first battery pack operation information; when it is predicted that a thermal runaway is about to occur in the battery pack, connecting the casing of the battery pack to the thermal runaway circulation loop, and disconnecting the connection between the casing of the battery pack and the liquid cooling circulation loop.

[0109] In one alternative embodiment, the method further includes: after the casing of the battery pack is connected to the thermal runaway circulation loop, obtaining second battery pack operation information collected by each thermal runaway sensor; when it is determined based on the second battery pack operation information that the battery pack has not experienced a thermal runaway, detecting whether only one battery pack is connected to the thermal runaway circulation loop; when only one battery pack is connected to the thermal runaway circulation loop or multiple battery packs are connected to the thermal runaway circulation loop and none of the multiple battery packs has experienced a thermal runaway, disconnecting the casing of the battery pack that has not experienced a thermal runaway from the thermal runaway circulation loop, and connecting at least one of the liquid cooling plate and the casing of the battery pack that has not experienced a thermal runaway to the liquid cooling circulation loop; when multiple battery packs are connected to the thermal runaway circulation loop and at least one of the multiple battery packs has experienced a thermal runaway, after the contaminated coolant in the battery pack that has not experienced a thermal runaway is discharged, disconnecting the casing of the battery pack that has not experienced a thermal runaway from the thermal runaway circulation loop, and connecting at least one of the liquid cooling plate and the casing of the battery pack that has not experienced a thermal runaway to the liquid cooling circulation loop.

[0110] In one alternative embodiment, predicting whether a thermal runaway occurs in the battery pack based on the first battery pack operation information is performed by a pre-trained prediction model; the method further includes: when it is determined based on the second battery pack operation information that the battery pack has not experienced a thermal runaway, storing the first battery pack operation information; when the quantity of the first battery pack operation information is greater than the first quantity threshold, updating the prediction model based on the stored first battery pack operation information.

[0111] In one alternative embodiment, the method further includes: when the number of battery packs predicted to be about to experience a thermal runaway based on the first battery pack operation information is greater than the second quantity threshold, simultaneously sending valve control signals corresponding to each battery pack predicted to be about to experience a thermal runaway, where the control signal is used to control the valve to connect the casing of the battery pack to the thermal runaway circulation loop, and disconnect the connection between the casing of the battery pack and the liquid cooling circulation loop.

[0112] In one alternative embodiment, the method further includes: when the battery pack has not experienced a thermal runaway, connecting at least one of the liquid cooling plate and the casing of the battery pack to the liquid cooling circulation loop.

[0113] In one alternative embodiment, connecting at least one of the liquid cooling plate and the housing of the battery pack to a liquid cooling circulation loop includes: obtaining the temperature of the battery pack; and connecting the liquid cooling plate or the housing of the battery pack to the liquid cooling circulation loop when the temperature of the battery pack is less than a temperature threshold.

[0114] In one alternative embodiment, the method further includes: obtaining the temperature rise rate of the battery pack when the temperature of the battery pack is less than a temperature threshold; connecting the liquid cooling plate of the battery pack to the liquid cooling circulation loop and disconnecting the connection between the housing of the battery pack and the liquid cooling circulation loop when the temperature rise rate of the battery pack is less than a rate threshold; and disconnecting the connection between the liquid cooling plate of the battery pack and the liquid cooling circulation loop and connecting the housing of the battery pack to the liquid cooling circulation loop when the temperature rise rate of the battery pack is greater than or equal to the rate threshold.

[0115] In one alternative embodiment, the method further includes: obtaining the temperature of the battery pack; and connecting the liquid cooling plate of the battery pack to the liquid cooling circulation loop and connecting the housing of the battery pack to the liquid cooling circulation loop when the temperature of the battery pack is greater than or equal to a temperature threshold.

[0116] In one alternative embodiment, obtaining the temperature of the battery pack includes: obtaining the respective initial temperatures collected by the respective temperature sensors of the battery pack and screening the respective initial temperatures to obtain the temperature of the battery pack.

[0117] For the specific limitations of the above thermal runaway control method, reference may be made to the limitations on the battery pack in the foregoing text, which will not be elaborated herein.

[0118] It should be understood that although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this document, the execution of these steps has no strict order limitation, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0119] In an exemplary embodiment, a controller is provided, which includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the controller is used to provide computing and control capabilities. The memory of the controller includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the controller is used to exchange information between the processor and external devices. The communication interface of the controller is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a thermal runaway control method is implemented.

[0120] Those skilled in the art can understand that the structure of the controller described above is only a part of the structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the above description, or combine certain components, or have different component arrangements.

[0121] In an embodiment, a controller is further provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the above method embodiments are implemented.

[0122] In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0123] In an embodiment, a computer program product is provided, including a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0124] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, artificial intelligence (AI) processors, etc., without limitation.

[0125] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in the present application.

[0126] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A thermal runaway control method, characterized in that: The method comprises: In the event of thermal runaway of the battery pack, the battery pack case is connected to the thermal runaway circulation loop, and the battery pack case is disconnected from the liquid cooling circulation loop; wherein the thermal runaway circulation loop is used for the circulation of the coolant in the case of the thermal runaway battery pack; and the liquid cooling circulation loop is used for the circulation of the coolant of the battery pack in normal operation; Acquire first battery pack operation information collected by each thermal runaway sensor, and predict whether thermal runaway occurs in the battery pack based on the first battery pack operation information; In the case where it is predicted that the battery pack is about to experience thermal runaway, connecting the battery pack case to a thermal runaway circulation loop, and disconnecting the battery pack case from a liquid cooling circulation loop; After the box of the battery pack is connected to the thermal runaway cycle, obtaining the second battery pack operation information collected by each of the thermal runaway sensors; When it is determined based on the second battery pack operation information that the battery pack does not have thermal runaway, detecting whether the thermal runaway cycle is connected to only one battery pack; When the thermal runaway circulation loop is connected to only one battery pack or the thermal runaway circulation loop is connected to multiple battery packs, and none of the multiple battery packs has thermal runaway, disconnecting the box of the battery pack that has not experienced thermal runaway from the thermal runaway circulation loop, and connecting at least one of the liquid cooling plate and the box of the battery pack that has not experienced thermal runaway to the liquid cooling circulation loop; In the case where the thermal runaway circulation loop is connected to multiple battery packs and thermal runaway occurs to at least one of the multiple battery packs, after the contaminated coolant in the battery pack that has not experienced thermal runaway is discharged, the case of the battery pack that has not experienced thermal runaway is disconnected from the thermal runaway circulation loop, and at least one of the liquid cooling plate and the case of the battery pack that has not experienced thermal runaway is connected to the liquid cooling circulation loop.

2. The thermal runaway control method according to claim 1, characterized in that: The method further comprises: In case of thermal runaway of the battery pack, the liquid cooling plate of the battery pack is connected to the liquid cooling circulation loop.

3. The thermal runaway control method according to claim 1, characterized in that: The predicting, based on the first battery pack operation information, whether the battery pack has thermal runaway is performed by a pre-trained prediction model; The method further comprises: When it is determined based on the second battery pack operation information that the battery pack does not have thermal runaway, storing the first battery pack operation information; When the amount of the first battery pack operation information is greater than a first amount threshold, the prediction model is updated based on the stored first battery pack operation information.

4. The thermal runaway control method according to claim 1, characterized in that: The method further comprises: In a case where the number of battery packs that are predicted to experience thermal runaway based on the first battery pack operating information is greater than a second number threshold, a valve control signal is sent in parallel to each valve corresponding to the battery pack that is about to experience thermal runaway, and the control signal is used to control the valve to connect the battery pack case with the thermal runaway circulation loop, and disconnect the battery pack case from the liquid cooling circulation loop.

5. The thermal runaway control method according to claim 1, characterized in that: The method further comprises: When the battery pack does not experience thermal runaway, at least one of the liquid cooling plate and the box of the battery pack is connected to the liquid cooling circulation loop.

6. The method according to claim 5, characterized in that The step of connecting at least one of the liquid cooling plate and the box of the battery pack to the liquid cooling circulation loop comprises: Obtaining the temperature of the battery pack; When the temperature of the battery pack is lower than a temperature threshold, a liquid cooling plate of the battery pack or a box of the battery pack is connected to the liquid cooling circulation loop.

7. The method according to claim 6, characterized in that The method further comprises: When the temperature of the battery pack is less than a temperature threshold, obtaining a heating rate of the battery pack; When the temperature rise rate of the battery pack is less than a rate threshold, connecting the liquid cooling plate of the battery pack to the liquid cooling circulation loop, and disconnecting the box of the battery pack from the liquid cooling circulation loop; When the temperature rise rate of the battery pack is greater than or equal to a rate threshold, the liquid cooling plate of the battery pack is disconnected from the liquid cooling circulation loop, and the box of the battery pack is connected to the liquid cooling circulation loop.

8. The method according to claim 5, characterized in that The method further comprises: Obtaining the temperature of the battery pack; When the temperature of the battery pack is greater than or equal to a temperature threshold, the liquid cooling plate of the battery pack is connected to a liquid cooling circulation loop, and the box of the battery pack is connected to the liquid cooling circulation loop.

9. The method according to any one of claims 6 to 8, characterized in that: The obtaining the temperature of the battery pack includes: Initial temperatures collected by temperature sensors of the battery pack are acquired, and the initial temperatures are screened to obtain the temperature of the battery pack.

10. A battery pack, characterized in that: The battery pack comprises: A box body, wherein a containing space is provided therein, the containing space is used to contain a cooling liquid, and the box body is provided with a first liquid inlet and a first liquid outlet; A battery cell is arranged in the accommodation space; Thermal runaway sensor, used to collect battery pack operation information; The first liquid inlet, the thermal runaway circulation loop and the liquid cooling circulation loop are respectively connected to a first three-way valve, and the first liquid outlet, the thermal runaway circulation loop and the liquid cooling circulation loop are respectively connected to a second three-way valve; A liquid cooling plate, adjacent to the box body, the liquid cooling plate is used to contain cooling liquid, and the liquid cooling plate is provided with a second liquid inlet and a second liquid outlet; The first three-way valve is connected to the liquid cooling circulation loop through a third three-way valve, and the other end of the third three-way valve is connected to the second liquid inlet; the second three-way valve is connected to the liquid cooling circulation loop through a fourth three-way valve, and the other end of the fourth three-way valve is connected to the second liquid outlet; In the case where it is determined based on the battery pack operation information that the battery pack has thermal runaway, the first three-way valve and the second three-way valve connect the box with the thermal runaway circulation loop, and disconnect the box from the liquid cooling circulation loop; In a case where it is determined that the battery pack is about to experience thermal runaway based on the first battery pack operation information collected by the thermal runaway sensor, the first three-way valve and the second three-way valve connect the box with the thermal runaway circulation loop, and disconnect the box from the liquid cooling circulation loop; After the box of the battery pack is connected to the thermal runaway circulation loop, it is determined based on the second battery pack operation information collected by each of the thermal runaway sensors that the battery pack has not experienced thermal runaway, and the thermal runaway circulation loop is only connected to one battery pack or the thermal runaway circulation loop is connected to multiple battery packs, and none of the multiple battery packs has experienced thermal runaway, the first three-way valve and the second three-way valve of the battery pack that has not experienced thermal runaway disconnect the box from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery pack that has not experienced thermal runaway connect at least one of the liquid cooling plate and the box with the liquid cooling circulation loop; Based on the second battery pack operation information collected by each of the thermal runaway sensors, it is determined that the battery pack has not experienced thermal runaway, the thermal runaway circulation loop connects multiple battery packs, and when at least one of the multiple battery packs has experienced thermal runaway, after the contaminated coolant in the battery pack that has not experienced thermal runaway is discharged, the first three-way valve and the second three-way valve of the battery pack that has not experienced thermal runaway disconnect the box and the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve of the battery pack that has not experienced thermal runaway connect at least one of the liquid cooling plate and the box with the liquid cooling circulation loop.

11. The battery pack according to claim 10, characterized in that: In the event of thermal runaway of the battery pack, the third three-way valve and the fourth three-way valve connect the liquid cooling plate with the liquid cooling circulation loop and disconnect the battery pack box from the liquid cooling circulation loop.

12. The battery pack according to claim 11, characterized in that: The first three-way valve and the second three-way valve of each battery pack that is about to experience thermal runaway receive valve control signals in parallel, and the control signals are used to control the first three-way valve and the second three-way valve to connect the battery pack case with the thermal runaway circulation loop, and disconnect the battery pack case from the liquid cooling circulation loop.

13. The battery pack according to claim 11, characterized in that: When the battery pack does not experience thermal runaway, the first three-way valve and the second three-way valve disconnect the box from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve and the fourth three-way valve connect at least one of the liquid cooling plate and the box to the liquid cooling circulation loop.

14. The battery pack according to claim 13, characterized in that: The battery pack further comprises: A temperature sensor, used to detect the temperature of the battery pack; When the thermal runaway sensor does not detect thermal runaway of the battery pack, and the temperature of the battery pack detected by the temperature sensor is less than a temperature threshold, the first three-way valve and the second three-way valve disconnect the box from the thermal runaway circulation loop, and the first three-way valve, the second three-way valve, the third three-way valve and the fourth three-way valve connect the box or the liquid cooling plate with the liquid cooling circulation loop.

15. The battery pack according to claim 14, characterized in that: The battery pack further comprises: A temperature sensor, used to detect the temperature of the battery pack; When the thermal runaway sensor does not detect thermal runaway of the battery pack, and the temperature of the battery pack detected by the temperature sensor is greater than or equal to a temperature threshold, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve are used to connect the liquid cooling plate with the liquid cooling circulation loop, and to connect the box with the liquid cooling circulation loop.

16. The battery pack according to claim 15, characterized in that: The first three-way valve, the second three-way valve, the third three-way valve and the fourth three-way valve are used to connect the liquid cooling plate with the liquid cooling circulation loop and disconnect the box body from the liquid cooling circulation loop when the temperature rise rate of the battery pack is less than a rate threshold; and disconnect the liquid cooling plate from the liquid cooling circulation loop and connect the box body with the liquid cooling circulation loop when the temperature rise rate of the battery pack is greater than or equal to a rate threshold.

17. The battery pack according to claim 10, characterized in that: The battery pack further comprises: An exhaust valve is located on the box body, and the exhaust valve is used to discharge the gas generated by thermal runaway when the battery pack has thermal runaway.

18. An energy storage system, characterized in that: The energy storage system comprises: At least two battery packs; A liquid cooling unit, used for controlling the temperature of the coolant and driving the circulation of the coolant; A liquid cooling circulation loop, wherein the at least two battery packs are connected to the liquid cooling unit through the liquid cooling circulation loop; A thermal runaway circulation loop, used for circulating the coolant in the box of a battery pack in thermal runaway; A controller for executing the thermal runaway control method according to any one of claims 1 to 9.

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