Battery pack and energy storage system

Abstract

The invention relates to a thermal runaway control method, a battery pack and an energy storage system. The method comprises the following steps: in the case of thermal runaway of a battery pack, communicating a box body of the battery pack with a thermal runaway circulation loop, and disconnecting the box body of the battery pack with a liquid cooling circulation loop; wherein the thermal runaway circulation loop is used for circulation of cooling liquid in a box body of a thermal runaway battery pack; and the liquid cooling circulation loop is used for circulation of cooling liquid of the battery pack which works normally. By adopting the method, the cooling liquid pollution can be avoided.

Description

[0001] This application is a divisional application for application number 2025102782533 (the name of the invention is: thermal runaway control method, battery pack and energy storage system, and the application date is March 10, 2025). Technical Field

[0002] The present application relates to the field of energy storage technology, and in particular to a battery pack and an energy storage system. Background Art

[0003] The energy storage system is equipped with battery cells. The battery cells generate heat during the charging and discharging process, causing the battery cell temperature to rise. If the battery cell temperature is not controlled, it may lead to reduced battery cell efficiency, shortened lifespan or thermal runaway. The natural heat dissipation of the battery cell cannot maintain the temperature within the operating range, so an external cooling system is required.

[0004] Immersion liquid cooling is a cooling system used in 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. The energy storage system includes a liquid cooling unit and liquid cooling pipelines. The immersion cooling medium flows through the pipelines and is cooled by the liquid cooling unit to control the temperature of the battery cells. Immersion liquid cooling offers excellent temperature control and safety, effectively reducing the temperature difference between battery cells and minimizing the risk of thermal runaway. It is a highly promising liquid cooling technology for energy storage devices. Furthermore, in immersion energy storage technology, the battery pack structure can be eliminated, and the battery cells can be directly arranged in a multi-layered manner in a battery cluster to improve system integration, simplify the structure, and reduce costs.

[0005] In traditional technology, the immersion PACK-level liquid cooling solution generally fills the PACK package with coolant and realizes the material and energy exchange between the PACK package and the liquid cooling circulation system through the water nozzle on the PACK package; or fills the PACK package with coolant and arranges a cold plate at the bottom of the PACK package. The coolant in the PACK package does not flow, and a water nozzle is opened on the cold plate. Material and energy are exchanged between the water nozzle and the liquid cooling circulation system, and then material and energy are exchanged between the cold plate and the coolant to achieve cooling of the battery cell.

[0006] However, in the immersion PACK-level liquid cooling solution in traditional technology, the battery cells are all in a liquid cooling circulation loop. If a single battery cell experiences thermal runaway, the large amount of waste gas, battery fluid, 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 coolant. Summary of the Invention

[0007] Based on this, it is necessary to provide a thermal runaway control method, battery pack and energy storage system that can avoid coolant contamination in response to the above technical problems.

[0008] In a first aspect, the present application provides a thermal runaway control method, the method comprising:

[0009] 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 circulation of coolant in the case of the thermally runaway battery pack; and the liquid cooling circulation loop is used for circulation of coolant in a battery pack that is operating normally.

[0010] In one optional embodiment, the method further includes:

[0011] In the event of thermal runaway of the battery pack, the liquid cooling plate of the battery pack is connected to the liquid cooling circulation loop.

[0012] In one optional embodiment, the method further includes:

[0013] acquiring first battery pack operation information collected by each thermal runaway sensor, and predicting whether thermal runaway occurs in the battery pack based on the first battery pack operation information;

[0014] When it is predicted that the battery pack is about to experience thermal runaway, 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.

[0015] In one optional embodiment, the method further includes:

[0016] After the battery pack housing is connected to the thermal runaway loop, obtaining second battery pack operation information collected by each of the thermal runaway sensors;

[0017] If it is determined based on the second battery pack operation information that the battery pack does not experience thermal runaway, detecting whether the thermal runaway loop is connected to only one battery pack;

[0018] If the thermal runaway loop is connected to only one battery pack or is connected to multiple battery packs and none of the multiple battery packs experience thermal runaway, disconnect the case of the battery pack that does not experience thermal runaway from the thermal runaway loop, and connect at least one of the liquid cooling plate and the case of the battery pack that does not experience thermal runaway to the liquid cooling loop;

[0019] In a case where the thermal runaway circulation loop is connected to multiple battery packs and thermal runaway occurs in 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.

[0020] In one optional embodiment, the predicting of whether thermal runaway occurs in the battery pack based on the first battery pack operation information is performed by using a pre-trained prediction model;

[0021] The method further comprises:

[0022] When it is determined based on the second battery pack operation information that thermal runaway does not occur in the battery pack, storing the first battery pack operation information;

[0023] 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.

[0024] In one optional embodiment, the method further includes:

[0025] 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 control signal is sent in parallel to the valve corresponding to each battery pack that is about to experience thermal runaway. 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.

[0026] In one optional embodiment, the method further includes:

[0027] When thermal runaway does not occur in the battery pack, at least one of the liquid cooling plate and the box of the battery pack is connected to the liquid cooling circulation loop.

[0028] In a second aspect, the present application further provides a battery pack, comprising:

[0029] The box body has a storage space therein for storing cooling liquid, and the box body has a first liquid inlet and a first liquid outlet;

[0030] A battery cell is arranged in the accommodation space;

[0031] Thermal runaway sensor, used to collect battery pack operating information;

[0032] 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;

[0033] When it is determined that thermal runaway occurs in the battery pack based on the battery pack operation information, 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.

[0034] In one optional embodiment, the battery pack further includes:

[0035] a liquid cooling plate, adjacent to the box body, the liquid cooling plate being used to contain cooling liquid, and the liquid cooling plate being provided with a second liquid inlet and a second liquid outlet;

[0036] 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;

[0037] 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.

[0038] In a third aspect, the present application further provides an energy storage system, comprising:

[0039] At least two battery packs;

[0040] A liquid cooling unit, used to control the temperature of the coolant and drive the circulation of the coolant;

[0041] a liquid cooling circulation loop, wherein the at least two battery packs are connected to the liquid cooling unit via the liquid cooling circulation loop;

[0042] A thermal runaway circulation loop, used for circulating coolant in the box of a thermal runaway battery pack;

[0043] A controller is used to execute the thermal runaway control method described in any one of the above embodiments.

[0044] The above-mentioned thermal runaway control method, battery pack and energy storage system connect the battery pack case with the thermal runaway circulation loop and disconnect the battery pack case from the liquid cooling circulation loop when thermal runaway occurs in the battery pack. This can prevent the coolant in the case of the thermally runaway battery pack from circulating into the liquid cooling circulation loop during thermal runaway, thereby preventing contaminated coolant from flowing into the case of the battery pack that has not experienced thermal runaway, thereby avoiding the waste of coolant caused by coolant contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 is a schematic diagram of a battery pack in one embodiment;

[0047] Figure 2 A schematic diagram of the states of the three-way valves and the circuit connection method in the case of thermal runaway in one embodiment;

[0048] Figure 3 A flowchart of the post-processing steps for thermal runaway in one embodiment;

[0049] Figure 4 A schematic diagram of a single mode using coolant for temperature control in an embodiment;

[0050] Figure 5 A schematic diagram of temperature control in parallel mode according to one embodiment;

[0051] Figure 6 is a flow chart of the control logic of a battery pack in one embodiment;

[0052] Figure 7 is a schematic diagram of an energy storage system in one embodiment;

[0053] Figure 8 FIG. 4 is a flow chart of a thermal runaway control method according to an embodiment. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0055] The present application embodiment provides a battery pack, specifically combined with Figure 1As shown, Figure 1 Schematic diagram of a battery pack in one embodiment, which includes a box, battery cells, a thermal runaway sensor, a first three-way valve, and a second three-way valve.

[0056] The box body includes a storage space for accommodating coolant, a first liquid inlet and a first liquid outlet, and a battery cell disposed within the storage space. A thermal runaway sensor is disposed within the storage space to collect operating information about the battery pack. The first liquid inlet, the thermal runaway loop, and the liquid cooling loop are each connected to a first three-way valve, while the first liquid outlet, the thermal runaway loop, and the liquid cooling loop are each connected to a second three-way valve.

[0057] The first three-way valve and the second three-way valve may be solenoid valves, and the switches of the solenoid valves are controlled by a controller so that the box is connected to the corresponding circuit.

[0058] If the controller determines that a battery pack is experiencing thermal runaway based on battery pack operating information, the first and second three-way valves are controlled to connect the battery case to the thermal runaway circuit and disconnect the battery case from the liquid cooling circuit. This prevents contaminated coolant from flowing into the battery case of a battery pack that is not experiencing thermal runaway, thus avoiding coolant waste caused by coolant contamination.

[0059] One point that needs to be explained is that this application does not limit the way in which the controller determines whether the battery pack has thermal runaway based on the battery pack operating information. However, for the sake of clarity, an embodiment is given. The thermal runaway sensor may include various types of sensors, such as a temperature sensor and a corresponding gas sensor. In the event of thermal runaway, the temperature of the battery pack will rise abnormally, and the gas sensor will detect the corresponding gas. Generally, when thermal runaway occurs, the temperature of the battery pack will change first. For this reason, in this application, when the temperature sensor detects an abnormal temperature change or the temperature is higher than the thermal runaway temperature threshold, it can be determined that the battery pack has thermal runaway. Alternatively, when the temperature detected by the temperature sensor is higher than the thermal runaway temperature threshold and the gas sensor detects that the concentration of the corresponding gas is greater than the concentration threshold, it can be determined that the battery pack has thermal runaway.

[0060] In the event of thermal runaway, the battery pack will leak, causing some substances to enter the coolant in the box, resulting in coolant contamination. In order to prevent the contaminated coolant from entering the liquid cooling circulation loop and expanding the scope of coolant contamination, in this application, when it is determined that the battery pack has thermal runaway, the box is connected to the thermal runaway circulation loop, and the connection between the box and the liquid cooling circulation loop is disconnected.

[0061] Optionally, in this application, if it is determined that the battery pack has thermal runaway, the connection between the housing and the liquid cooling circuit can be disconnected first, and then the housing and the thermal runaway circuit can be reconnected. In other embodiments, if it is determined that the battery pack has thermal runaway, the connection between the housing and the liquid cooling circuit can be disconnected while the housing and the thermal runaway circuit are reconnected. This is not specifically limited here, and it is only necessary to ensure that contaminated coolant cannot flow back into the liquid cooling circuit if it is determined that the battery pack has thermal runaway.

[0062] Continue to combine Figure 1 As shown, in one of the optional embodiments, the battery pack further includes a liquid cooling plate adjacent to the box body, the liquid cooling plate is used to accommodate cooling liquid, and the liquid cooling plate is provided with a second liquid inlet and a second liquid outlet.

[0063] 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.

[0064] Among them, 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.

[0065] In this way, when the battery pack experiences thermal runaway, in order to prevent the thermal runaway from developing more violently, the battery pack is cooled by a liquid cooling plate to keep the thermal runaway within a controllable range. Figure 2 The status of each three-way valve and the circuit connection method in the case of thermal runaway are shown.

[0066] In some optional embodiments, in order to prevent coolant from entering the liquid cooling circulation loop during thermal runaway, thermal runaway is predicted. When it is determined that the battery pack is about to experience thermal runaway based on the first battery pack operating information collected by the thermal runaway sensor, the first three-way valve and the second three-way valve connect the box body with the thermal runaway circulation loop, and disconnect the box body from the liquid cooling circulation loop.

[0067] The method of determining that a battery pack is about to experience thermal runaway based on the first battery pack operating information may include any one of the following: detecting whether the temperature in the first battery pack operating information has a sudden change, and if the temperature has a sudden change, determining that the battery pack is about to experience thermal runaway; processing the first battery pack operating information through a pre-trained prediction model to determine whether thermal runaway is about to occur.

[0068] Among them, since thermal runaway is generally preceded by a sudden change in temperature, and leakage will only occur after the temperature changes suddenly, it is possible to first predict whether thermal runaway will occur based on whether the temperature changes suddenly.

[0069] The pre-trained prediction model can be trained based on historical battery pack operation information collected before thermal runaway occurred in the past. The prediction model can use a neural network, etc., and no specific limitation is made here.

[0070] In one of the optional embodiments, the prediction of whether thermal runaway occurs in the battery pack based on the first battery pack operating information is performed by a pre-trained prediction model; the method also includes: when it is determined that thermal runaway does not occur in the battery pack based on the second battery pack operating information, storing the first battery pack operating information; when the amount of the first battery pack operating information is greater than a first quantity threshold, updating the prediction model based on the stored first battery pack operating information.

[0071] In order to improve the accuracy of the prediction, the prediction model is also updated in this application. When the prediction model predicts that thermal runaway will occur, but it is actually determined based on the second battery pack operating information that the battery pack has not experienced thermal runaway, the first battery pack operating information can be stored. The stored first battery pack operating information can be used to update the prediction model. In order to avoid the cost problem caused by frequent updates of the prediction model, the prediction model will only be updated when the amount of first battery pack operating information is greater than the first quantity threshold. This not only balances the cost but also improves the accuracy of the prediction model.

[0072] In some optional embodiments, to improve accuracy, the present application may determine that a battery pack is about to experience thermal runaway only when it is determined based on temperature or based on a prediction model. Alternatively, to improve system sensitivity, the application may determine that a battery pack is about to experience thermal runaway only when it is determined based on temperature or based on a prediction model. This is not specifically limited here.

[0073] Among them, in the present 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 with the thermal runaway circulation loop, and disconnect the box from the liquid cooling circulation loop, thereby avoiding the expansion of the coolant contamination area.

[0074] In addition, the control mode can be predetermined in the present application, that is, whether it is a 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 with the thermal runaway circulation loop, and disconnect the box body from the liquid cooling circulation loop; otherwise, after thermal runaway is sent, the first three-way valve and the second three-way valve connect the box body with the thermal runaway circulation loop, and disconnect the box body from the liquid cooling circulation loop.

[0075] In some optional embodiments, the battery pack further includes a vent valve located on the housing. This vent valve is used to discharge gases generated by thermal runaway in the event of thermal runaway. This allows the housing to be connected to the thermal runaway circuit to discharge contaminated coolant within the housing, while also allowing gases generated by thermal runaway to be discharged through the vent valve.

[0076] In some optional embodiments, after the battery pack case is connected to the thermal runaway circulation loop, 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 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 have 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 case 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 case to the liquid cooling circulation loop. 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, the thermal runaway circulation loop is connected to multiple battery packs, and at least one battery pack among 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.

[0077] For ease of understanding, combined Figure 3 As shown, Figure 3 This is a flowchart of the thermal runaway post-processing steps in one embodiment. In this embodiment, based on the operating information of the first battery pack, it is predicted that the battery pack will experience thermal runaway. To this end, 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.

[0078] The subsequent thermal runaway sensor continues to collect the second battery pack operating information of the battery pack, and based on the second battery pack operating information, it is determined that the battery pack ultimately does not experience thermal runaway. In this case, the battery pack needs to be reconnected to enable the energy storage system to operate normally.

[0079] Among them, since the battery pack is connected to the thermal runaway loop, if there are other battery packs that have thermal runaway, the coolant in the box of the battery pack that has not sent thermal runaway but is connected to the thermal runaway loop will also be contaminated; if there are no other battery packs that have thermal runaway, the coolant in the box of the battery pack is considered to be uncontaminated.

[0080] The first case: 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 experience thermal runaway, 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 pack that does not experience 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 does not experience thermal runaway connect at least one of the liquid cooling plate and the box with the liquid cooling circulation loop.

[0081] The second situation: 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, the thermal runaway circulation loop is connected to multiple battery packs, and at least one battery pack among 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 the liquid cooling plate and at least one of the box and the liquid cooling circulation loop.

[0082] In the above two situations, if the coolant in the battery pack case is not contaminated, the battery pack can be directly reconnected to the liquid cooling circuit through valve control to ensure normal operation. If the coolant in the battery pack case is contaminated, the coolant in the battery pack case needs to be drained and then reconnected.

[0083] When the battery pack is reconnected to the liquid cooling loop, the cooling mode must be determined: parallel or single. The parallel mode includes both liquid cooling plate cooling and cabinet cooling. The single mode includes only liquid cooling plate cooling or only cabinet cooling. Specific definitions for parallel and single modes are provided below.

[0084] In some optional 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 battery pack housing to the thermal runaway circuit and disconnect the battery pack housing from the liquid cooling circuit. To improve control efficiency, the present application controls the first and second three-way valves in parallel when the number of battery packs about to experience thermal runaway exceeds a threshold number, thereby preventing contaminated coolant from entering the liquid cooling circuit due to delays in the valve control signals.

[0085] The parallel operation mentioned here includes the parallel operation of each battery pack that is about to experience thermal runaway, and may also include the parallel operation 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 may be a distributed controller, and each controller can be assigned to control the valves of a corresponding number of battery packs, thereby achieving parallel transmission of valve control signals and improving control efficiency.

[0086] In some optional embodiments, when thermal runaway does not occur in the battery pack, 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.

[0087] In this application, the parallel mode and the single mode are realized by controlling the valve, wherein the valve is controlled based on the temperature and the heating rate.

[0088] In some optional embodiments, the battery pack further includes a temperature sensor, which is used to collect the temperature of the battery pack. The number of the temperature sensor is at least one. In order to improve the accuracy of the temperature sensor collection, the position of the at least one temperature sensor may include the surface of the battery cell, so that the problem of the battery cell can be accurately collected. This is also because the temperature of the battery cell will first mutate during thermal runaway. In some optional embodiments, the temperature sensors on the surface of the battery cell should be evenly arranged to more accurately obtain the temperature of each battery cell. In other optional embodiments, some temperature sensors can also be set at a certain distance from the battery cell in the battery pack box to understand the temperature changes at various locations in the box. In the case of 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 a judgment can be made to improve the response speed of the system.

[0089] In some optional 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 lower than the 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 to the liquid cooling circulation loop.

[0090] In one of the optional 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 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 with the liquid cooling circulation loop, and to connect the box with the liquid cooling circulation loop.

[0091] Among them, when the temperature is lower than the temperature threshold, the present application adopts a single mode to cool the battery pack, that is, the battery pack is cooled only by the coolant in the liquid cooling plate or only by the coolant in the box.

[0092] When the temperature is greater than or equal to the temperature threshold, the present application adopts a parallel mode to cool the battery pack, that is, the battery pack is cooled by the coolant in the liquid cooling plate and the coolant in the box.

[0093] Specifically, combined Figure 4 and Figure 5 As shown, Figure 4 A schematic diagram of a single mode using coolant for temperature control in an embodiment; Figure 5 FIG. 1 is a schematic diagram of temperature control in parallel mode in one embodiment. Figure 4 In the case of detecting that the temperature of the battery pack is lower than the temperature threshold, the battery pack is cooled only by the coolant in the liquid cooling plate. At this time, only the liquid cooling plate is connected to the liquid cooling loop, which can achieve cooling while avoiding the circulation of excess coolant. 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 by the coolant in the liquid cooling plate and the coolant in the box, that is, the third three-way valve and the fourth three-way valve are both opened, and the first three-way valve and the second three-way valve close the passage between the battery pack box and the thermal runaway circulation loop. At this time, the liquid cooling plate and the battery pack box are connected in parallel, and the coolant flows in the battery pack box and the liquid cooling plate, realizing direct convection heat exchange between the coolant of the battery pack and the battery cells and indirect heat exchange of the liquid cooling plate, thereby improving heat exchange efficiency.

[0094] In one of the optional embodiments, 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 and the liquid cooling circulation loop and disconnect the box body and the liquid cooling circulation loop when the heating rate of the battery pack is less than the rate threshold; when the heating rate of the battery pack is greater than or equal to the rate threshold, disconnect the liquid cooling plate and the liquid cooling circulation loop and connect the box body and the liquid cooling circulation loop.

[0095] 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 and the liquid cooling circulation loop are connected, and the connection between the box and the liquid cooling circulation loop is disconnected, that is, indirect heat exchange can be achieved by the liquid cooling plate.

[0096] If the temperature rise rate is greater than or equal to the rate threshold, the liquid cooling plate is disconnected from the liquid cooling circuit, and the box is connected to the liquid cooling circuit. This means that the liquid cooling plate flows within the battery pack box, enabling direct convection heat transfer between the battery pack's coolant and the battery cells, improving heat exchange efficiency.

[0097] For ease of understanding, combined Figure 6 As shown, Figure 6 Flowchart of the control logic of a battery pack in one embodiment. In this embodiment, first operating information of each battery pack is collected by a thermal runaway sensor. When it is determined that battery pack No. n has experienced or is about to experience thermal runaway based on the first operating information, the three-way valve of the thermal runaway circulation loop where battery pack No. n is located is opened to connect battery pack No. n to the thermal runaway circulation loop, and the connection between the case of battery pack No. n and the liquid cooling circulation loop is disconnected. After battery pack No. n is connected to the thermal runaway circulation loop, the water pump of the thermal runaway circulation loop is turned on.

[0098] If it is determined based on the first operating information that the battery pack has not experienced thermal runaway, the temperature of each battery pack is obtained. If the temperature is greater than a temperature threshold, heat exchange is performed in parallel mode. If the temperature is less than the temperature threshold, the heating rate is obtained. If the heating rate is greater than or equal to the rate threshold, the connection between the liquid cooling plate and the liquid cooling circuit is disconnected, and the connection between the box and the liquid cooling circuit is connected. If the heating rate is less than the rate threshold, the connection between the liquid cooling plate and the liquid cooling circuit is connected, and the connection between the box and the liquid cooling circuit is opened.

[0099] In the above embodiment, different heat exchange modes are selected based on temperature and heating rate, which can improve heat exchange efficiency while achieving the purpose of saving costs.

[0100] Combine Figure 7 As shown, 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 to circulate the coolant in the box of the battery pack in thermal runaway. A controller is used to execute the thermal runaway control method to select different heat exchange modes.

[0101] The battery pack is connected in series or in parallel with other battery packs through a liquid cooling circulation loop to connect to the liquid cooling unit, so that the coolant flowing through the liquid cooling unit for temperature control can exchange substances with the coolant in the battery pack to achieve temperature control.

[0102] 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 monitors the temperature of the coolant at the inlet and outlet of the unit. The refrigeration cycle heat exchange unit uses a fan to exchange heat between air and coolant, which is then circulated to cool the battery cells. The water pump drives the coolant through the liquid cooling loop. The heating unit heats the coolant, for example, to preheat the battery pack, but this is not specifically defined here.

[0103] In one of the optional embodiments, the liquid cooling circulation loop is used to circulate the coolant located in the liquid cooling unit, the coolant located in the cooling liquid 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 located in the liquid cooling unit, the coolant located in the cooling liquid circulation loop, and the coolant in the battery pack case; or the liquid cooling circulation loop is used to circulate the coolant located in the liquid cooling unit, the coolant located in the cooling liquid circulation loop, the coolant in the cooling plate of the battery pack, and the coolant in the battery pack case.

[0104] In one of the optional embodiments, the thermal runaway circulation loop is used to circulate the coolant in the box of the battery pack in thermal runaway and the coolant in the thermal runaway circulation loop.

[0105] Optionally, the energy storage system further includes an expansion tank, the function of which is to avoid overpressure caused by high temperature during thermal runaway. The water pump is used to drive the flow of coolant in the thermal runaway circulation loop to avoid excessively high local temperatures in the battery pack. The battery packs are connected to the loop in series and parallel through multiple electromagnetic three-way valves. The electromagnetic three-way valves in the thermal runaway circulation loop remain closed under normal operating conditions.

[0106] In an exemplary embodiment, Figure 8 As shown, a thermal runaway control method is provided, which is applied to Figure 7 The controller in the example is used to illustrate the process, which includes the following steps.

[0107] S802: 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; the thermal runaway circulation loop is used to circulate the coolant in the case of the thermally runaway battery pack; and the liquid cooling circulation loop is used to circulate the coolant of the battery pack in normal operation.

[0108] In one of the optional embodiments, the method further includes: in the event of thermal runaway of the battery pack, connecting the liquid cooling plate of the battery pack to the liquid cooling circulation loop.

[0109] In one of the optional embodiments, the method further includes: obtaining first battery pack operating information collected by each thermal runaway sensor, and predicting whether the battery pack will experience thermal runaway based on the first battery pack operating information; when it is predicted that the battery pack will experience thermal runaway, connecting the battery pack case to the thermal runaway circulation loop, and disconnecting the battery pack case from the liquid cooling circulation loop.

[0110] In one of the optional embodiments, the method further includes: after the battery pack case is connected to the thermal runaway 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 thermal runaway, detecting whether the thermal runaway loop is connected to only one battery pack; when the thermal runaway loop is connected to only one battery pack or the thermal runaway loop is connected to multiple battery packs, and none of the multiple battery packs have experienced thermal runaway, disconnecting the case of the battery pack that has not experienced thermal runaway from the thermal runaway loop, and connecting at least one of the liquid cooling plate and the case of the battery pack that has not experienced thermal runaway to the liquid cooling loop; when the thermal runaway 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 pack that has not experienced thermal runaway is discharged, disconnecting the case of the battery pack that has not experienced thermal runaway from the thermal runaway loop, and connecting at least one of the liquid cooling plate and the case of the battery pack that has not experienced thermal runaway to the liquid cooling loop.

[0111] In one of the optional embodiments, the prediction of whether the battery pack has thermal runaway is performed based on the first battery pack operating information by a pre-trained prediction model; the method also includes: when it is determined based on the second battery pack operating information that the battery pack has not had thermal runaway, storing the first battery pack operating information; when the amount of the first battery pack operating information is greater than a first quantity threshold, updating the prediction model based on the stored first battery pack operating information.

[0112] In one of the optional embodiments, the method further includes: when it is predicted based on the operating information of the first battery pack that the number of battery packs that are about to experience thermal runaway is greater than a second number threshold, sending control signals in parallel to the valves corresponding to each battery pack that is about to experience thermal runaway, the control signals are used to control the valves to connect the battery pack case with the thermal runaway circulation loop, and to disconnect the battery pack case from the liquid cooling circulation loop.

[0113] In one of the optional embodiments, the method further includes: connecting at least one of the liquid cooling plate and the box of the battery pack to a liquid cooling circulation loop when thermal runaway does not occur in the battery pack.

[0114] In one of the optional embodiments, at least one of the liquid cooling plate and the box of the battery pack is connected to the liquid cooling circulation loop, including: obtaining the temperature of the battery pack; when the temperature of the battery pack is lower than a temperature threshold, connecting the liquid cooling plate of the battery pack or the box of the battery pack to the liquid cooling circulation loop.

[0115] In one of the optional embodiments, the method further includes: when the temperature of the battery pack is less than a temperature threshold, obtaining the heating rate of the battery pack; when the heating rate of the battery pack is less than the rate threshold, connecting the liquid cooling plate of the battery pack with the liquid cooling circulation loop, and disconnecting the battery pack case from the liquid cooling circulation loop; when the heating rate of the battery pack is greater than or equal to the rate threshold, disconnecting the liquid cooling plate of the battery pack with the liquid cooling circulation loop, and connecting the battery pack case to the liquid cooling circulation loop.

[0116] In one of the optional embodiments, the method further includes: obtaining the temperature of the battery pack; when the temperature of the battery pack is greater than or equal to a temperature threshold, connecting the liquid cooling plate of the battery pack with the liquid cooling circulation loop, and connecting the battery pack box with the liquid cooling circulation loop.

[0117] In one optional embodiment, obtaining the temperature of the battery pack includes: obtaining initial temperatures collected by temperature sensors of the battery pack, and screening the initial temperatures to obtain the temperature of the battery pack.

[0118] The specific limitations of the thermal runaway control method can be found in the above limitations on the battery pack and will not be repeated here.

[0119] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0120] In an exemplary embodiment, a controller is provided, comprising a processor, a memory, an input / output interface (I / O), and a communication interface. The processor, memory, and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface. The processor of the controller is configured to provide computing and control capabilities. The memory of the controller comprises 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 computer program in the non-volatile storage medium. The input / output interface of the controller is configured to exchange information between the processor and an external device. The communication interface of the controller is configured to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a thermal runaway control method is implemented.

[0121] Those skilled in the art will understand that the structure of the controller described above is only a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the above description, or combine certain components, or have a different component arrangement.

[0122] In one embodiment, a controller is further provided, comprising a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0123] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0124] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0125] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the 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-mentioned methods. In particular, any reference to memory, database, or other media used in the embodiments provided in this 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), magnetic 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 take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0126] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, 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, they should be considered to be within the scope of this application.

[0127] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A battery pack, characterized in that: The battery pack includes: The box body has a storage space therein for storing cooling liquid, and the box body has 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 operating 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 being used to contain cooling liquid, and the liquid cooling plate being 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; when the battery pack is predicted to undergo thermal runaway through a pre-trained prediction model 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 battery pack case is connected to the thermal runaway cycle, when it is determined that the battery pack has not experienced thermal runaway based on the second battery pack operating information collected by each of the thermal runaway sensors, the first battery pack operating information is stored, and the stored first battery pack operating information whose amount is greater than a first quantity threshold is used to update the prediction model.

2. The battery pack according to claim 1, wherein: After the case of the battery pack is connected to the thermal runaway loop, if it is determined based on the second battery pack operating information collected by each of the thermal runaway sensors that thermal runaway has not occurred in the battery pack, and the thermal runaway loop is connected to only one battery pack, or the thermal runaway loop is connected to multiple battery packs, and none of the multiple battery packs have 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 case from the thermal runaway 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 case with the liquid cooling 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 is connected to multiple battery packs, and when thermal runaway has occurred in 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 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.

3. The battery pack according to claim 1, wherein: In the event of thermal runaway of the battery pack, 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; 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.

4. The battery pack according to claim 1, wherein: 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.

5. The battery pack according to claim 1, wherein: When thermal runaway does not occur in the battery pack, 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.

6. The battery pack according to claim 1, wherein: The battery pack further includes: a temperature sensor, configured to detect the temperature of the battery pack; When it is determined that thermal runaway has not occurred in the battery pack based on the first battery pack operation information collected by the thermal runaway sensor, and the temperature of the battery pack detected by the temperature sensor is lower 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.

7. The battery pack according to claim 6, characterized in that: The battery pack further includes: a temperature sensor, configured to detect the temperature of the battery pack; When it is determined that thermal runaway has not occurred in the battery pack based on the first battery pack operation information collected by the thermal runaway sensor, 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.

8. The battery pack according to claim 7, 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 and 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 and the liquid cooling circulation loop and connect the box body to the liquid cooling circulation loop when the temperature rise rate of the battery pack is greater than or equal to the rate threshold.

9. The battery pack according to claim 1, wherein: The battery pack further includes: An exhaust valve is located on the box body and is used to discharge gas generated by thermal runaway in the event of thermal runaway of the battery pack.

10. An energy storage system, characterized in that: The energy storage system comprises: At least two battery packs according to any one of claims 1 to 9; A liquid cooling unit, used to control the temperature of the coolant and drive the circulation of the coolant; A liquid cooling circulation loop, wherein 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 coolant in the box of a thermal runaway battery pack; A controller is configured to control each three-way valve in the battery pack based on first battery pack operation information collected by a thermal runaway sensor in the battery pack.

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