Method and system for triggering thermal runaway of battery

Abstract

A method and system for triggering thermal runaway of a battery, capable of triggering thermal runaway of a battery cell during battery testing. The method comprises: charging a target battery cell in a battery, such that the power level of the target battery cell is greater than the power levels of the remaining battery cells in the battery; and when the power level of the target battery cell is greater than the power levels of the remaining battery cells, charging the battery.

Description

Method and system for triggering battery thermal runaway

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311755533.6, filed on December 19, 2023, entitled “Method and system for triggering battery thermal runaway,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of batteries, and in particular to a method and system for triggering thermal runaway of a battery. Background Art

[0004] Batteries, as energy storage devices, are widely used in electronics, electric vehicles, energy storage power stations, and many other fields. Whether battery safety meets operational requirements is a topic of extensive research. Thermal runaway is a battery safety issue. When thermal runaway occurs, the internal temperature of the battery rises, potentially triggering a chain reaction that can lead to fire, explosion, and other consequences. Furthermore, the thermal runaway process can cause it to spread. Accidents caused by thermal runaway and its spread can easily result in casualties and property damage.

[0005] Typically, triggering thermal runaway in a battery cell is necessary to test how the runaway spreads throughout the battery and analyze battery safety. Therefore, how to trigger thermal runaway in a battery cell becomes a pressing issue.

[0006] Summary of the Invention

[0007] Embodiments of the present application provide a method and system for triggering battery thermal runaway, which can trigger thermal runaway of a battery cell during a battery test.

[0008] In a first aspect, a method for triggering thermal runaway of a battery is provided, the method comprising: charging a target battery cell in a battery so that the power of the target battery cell is greater than the power of other battery cells in the battery; and charging the battery when the power of the target battery cell is greater than the power of the other battery cells.

[0009] The electrical quantity may be, for example, any one of SOC, SOE and capacity.

[0010] In an embodiment of the present application, a target battery cell is charged to a level higher than that of the other battery cells in the battery. By creating a charge imbalance between the target battery cell and the other battery cells, the target battery cell can experience thermal runaway due to overcharging before the other batteries reach the charge cutoff voltage during charging of the entire battery, while the other battery cells operate within a normal charge range. This method, firstly, eliminates the need to prepare special battery cells or batteries during production, nor does it require complex battery modifications. This makes the testing process unrestricted by time and space, making it widely applicable to random battery inspections. Secondly, it does not damage the battery structure, reducing the impact on the battery's airtightness and high-voltage electrical connections. Finally, it can simulate thermal runaway behavior during dynamic charging.

[0011] In some possible implementations, before charging the target battery cell in the battery, the method further includes: adjusting the battery's charge to a preset charge, where the preset charge is less than the charge of the battery when fully charged. This allows the consistency of the initial states of the battery cells in the battery to be maintained.

[0012] In some possible implementations, the preset power is less than or equal to 85% of the power in a fully charged state. For example, the preset power is 50%, 60%, 70% or 80% of the power in a fully charged state, thereby reducing the risk of overcharging the target battery cell during charging of the target battery cell.

[0013] In some possible implementations, before adjusting the battery's charge to a preset charge, the method further includes: charging the battery to a full charge state; wherein adjusting the battery's charge to the preset charge includes: discharging the battery from the full charge state to the preset charge. In other words, the battery can be first charged to a full charge state and then discharged to the preset charge to adjust the battery's initial charge.

[0014] In some possible implementations, charging the target battery cell in the battery so that the target battery cell has a greater charge than the other battery cells in the battery includes: charging the target battery cell so that the charge of the target battery cell exceeds the charge of the other battery cells by more than or equal to 15% of the charge in a fully charged state, and is less than or equal to 70% of the charge in a fully charged state. For example, the charge of the target battery cell exceeds the charge of the other battery cells by 20%, 30%, 40% or 50% of the charge in a fully charged state. In this way, the risk of overcharging the target battery cell can be reduced during charging, and thermal runaway of the target battery cell can be caused during charging of the entire battery, thereby achieving effective testing of the battery.

[0015] In some possible implementations, the target battery cell is housed in a housing comprising a first housing portion and a second housing portion that interlock with each other. The electrode terminals of the target battery cell face the first housing portion. During charging of the target battery cell, the first housing portion is removed to allow connection between the electrode terminals and a charging and discharging device. Charging the target battery cell in the battery includes controlling the charging and discharging device to charge the target battery cell.

[0016] Since only the first housing section of the case needs to be opened and the leads of the charging and discharging device connected to the electrode terminals of the target battery cell, once the charging and discharging device has finished charging the target battery cell, the connection between the target battery cell and the charging and discharging device can be disconnected, and the first housing section can be re-closed on the second housing section, restoring the battery to the same state as in actual use. During this process, the battery structure is not damaged, and the battery's airtightness and high-voltage connectors are not affected.

[0017] In some possible implementations, the end of the positive lead of the charging and discharging device is glued to the positive electrode terminal of the target battery cell, and the end of the negative lead of the charging and discharging device is glued to the negative electrode terminal of the target battery cell. This connection method can save costs.

[0018] In some possible implementations, the end of the positive lead of the charging and discharging device is pressed by a pressing mechanism into contact with the positive electrode terminal of the target battery cell, and the end of the negative lead of the charging and discharging device is pressed by the pressing mechanism into contact with the negative electrode terminal of the target battery cell. Because the pressing mechanism directly presses the end of the lead against the electrode terminal of the target battery cell, the contact reliability between the lead and the electrode terminal is improved, and the probability of poor contact between the lead and the electrode terminal during testing is reduced.

[0019] In some possible implementations, before charging the target battery cell in the battery, the method further includes: disabling a balancing function of a battery management system of the battery.

[0020] The battery balancing function is to adjust the voltage difference between battery cells or the voltage difference between battery cell groups to an appropriate range, so that each battery cell maintains a substantially identical state during use, reducing the risk of overcharge or over-discharge. Because the embodiment of the present application needs to trigger thermal runaway of the target battery cell due to overcharge, shielding the balancing function of the battery management system can reduce the risk of the target battery cell being unable to trigger thermal runaway due to the equalization of the power difference between the target battery cell and other battery cells, thereby reducing the impact of the balancing function on the testing process.

[0021] In some possible implementations, before charging the battery, the method further includes: shielding an overvoltage protection function of a battery management system of the battery.

[0022] Since excessive voltage may damage the battery, the battery's overvoltage protection function can reduce the probability of abnormal or excessive output voltage during the charging and discharging process. For example, when it is detected that the battery voltage exceeds the rated voltage, the charge and discharge circuit can be disconnected to prevent the voltage from continuing to rise. Since the embodiment of the present application needs to trigger thermal runaway of the target battery cell due to overcharging, it is necessary to disable the overvoltage protection function to reduce the risk of the charging circuit being disconnected before the target battery cell experiences thermal runaway, resulting in the termination of the test process. This reduces the impact of the overvoltage protection function on the test process.

[0023] In some possible implementations, the thermal runaway condition includes at least one of the following conditions: the battery voltage, the battery temperature rise rate, and the battery status information meet the thermal runaway condition; the battery temperature reaches a temperature threshold; the battery charging time reaches a time threshold; and the battery voltage reaches a voltage threshold. For example, the time threshold is greater than or equal to 4 hours, and / or the temperature threshold is greater than or equal to 300°C, and / or the voltage threshold is greater than or equal to 1.1 times or 1.2 times the battery's charge cutoff voltage. Reasonable setting of thermal runaway conditions and test stop conditions such as charging time, battery temperature, and voltage can effectively control the test process without affecting the test results.

[0024] In some possible implementations, the thermal runaway condition includes: the battery voltage is greater than or equal to 1V and the battery temperature rise rate for three consecutive samples is greater than or equal to 3°C / s, or the battery status information includes fire or explosion; or the battery voltage drop exceeds 25% of the initial voltage or the battery temperature exceeds a temperature threshold, and the battery temperature rise rate is greater than or equal to 1°C / s. Using the thermal runaway conditions in relevant standards to determine whether a battery has experienced thermal runaway facilitates the integration of the test scheme of the present embodiment with existing standards and promotes the promotion of this test scheme.

[0025] In some possible implementations, the target battery cell includes one or more battery cells, and the multiple battery cells are connected in parallel and / or in series to meet various testing requirements.

[0026] In some possible implementations, the battery includes a battery box or a battery cluster.

[0027] For example, the battery is an electrical box, and the target battery cell is located in the middle of the electrical box.

[0028] For another example, the battery is a battery cluster including multiple electrical boxes, the electrical box where the target battery cell is located is located in the middle of the battery cluster, and the target battery cell is located in the middle of the electrical box where it is located.

[0029] Selecting the electrical box in the middle of the battery cluster and / or selecting the battery cell in the middle of the electrical box as the target battery cell can make the thermal runaway spread more uniform, thereby making the test results more comprehensive and stable.

[0030] In some possible implementations, charging the battery includes: performing constant current charging or constant power charging on the battery. If the battery is used in a power system, the battery may be charged with a constant current, for example, with a constant current charging current greater than or equal to 1C, or equal to the maximum allowable current of the battery; if the battery is used in an energy storage system, the battery may be charged with a constant power, thereby meeting the battery's application in different scenarios.

[0031] In some possible implementations, the method further includes: during charging of the battery, monitoring at least one of the following information of the battery and a monitoring object adjacent to the battery: charging time, voltage, temperature, temperature rise rate, and status information. The status information may include, for example, at least one of the following: expansion, leakage, smoking, fire, explosion, and location of a housing rupture.

[0032] During the battery charging process, the battery's charging time, voltage, current, temperature, and temperature rise rate are recorded. The voltage, current, temperature, and temperature rise rate of the monitoring object adjacent to the battery are also recorded. Test phenomena, including swelling, leakage, smoke, fire, explosion, and the location of the case rupture, are also recorded. By recording this battery information and time delay during charging, it is possible to promptly determine whether thermal runaway has been triggered.

[0033] In some possible implementations, the method further includes: testing insulation performance of the battery.

[0034] The insulation performance of the battery can reduce the risk of leakage in the high-voltage circuit. When the battery swells, leaks, smokes, catches fire, explodes, or the case ruptures, the insulation performance of the battery is likely to have been destroyed. However, when thermal runaway of the target battery cell is triggered or the test is stopped, if no obvious thermal runaway phenomenon is observed in the monitoring of the battery itself and its vicinity, the insulation performance test of the battery can better understand the risks caused by thermal runaway, making the battery test more comprehensive and reliable.

[0035] In a second aspect, a system for triggering battery thermal runaway is provided, the system comprising a battery, a charge-discharge module, and a control module. The battery comprises a target battery cell, and the control module is configured to: control the charge-discharge module to charge the target battery cell so that the target battery cell has a greater charge than other battery cells in the battery; and control the charge-discharge module to charge the battery if the charge of the target battery cell is greater than the charge of the other battery cells.

[0036] The electrical quantity may be, for example, any one of SOC, SOE and capacity.

[0037] In some possible implementations, the charge and discharge module includes a first charge and discharge device and a second charge and discharge device, wherein the first charge and discharge device is used to charge and discharge the target battery cell, and the second charge and discharge device is used to charge and discharge the battery.

[0038] In some possible implementations, the target battery cell is accommodated in a box body, which includes a first box body portion and a second box body portion that are interlocked with each other, and the electrode terminals of the target battery cell are facing the first box body portion. wherein, during the process of the first charging and discharging device charging the target battery cell, the first box body portion is in a removed state to connect the electrode terminals to the first charging and discharging device.

[0039] In some possible implementations, the end of the positive lead of the first charge and discharge device is pasted to the positive electrode terminal of the target battery cell, and the end of the negative lead of the first charge and discharge device is pasted to the negative electrode terminal of the target battery cell.

[0040] In some possible implementations, the end of the positive electrode wire of the first charging and discharging device contacts the positive electrode terminal of the target battery cell through the pressing of the pressing mechanism, and the end of the negative electrode wire of the first charging and discharging device contacts the negative electrode terminal of the target battery cell through the pressing of the pressing mechanism.

[0041] In some possible implementations, the charge and discharge module is further configured to adjust the charge of the battery to a preset charge before charging the target battery cell in the battery, where the preset charge is less than the charge of the battery in a fully charged state.

[0042] In some possible implementations, the preset power level is less than or equal to 85% of the power level in a fully charged state. For example, the preset power level is 50%, 60%, 70% or 80% of the power level in a fully charged state.

[0043] In some possible implementations, the charging and discharging module is specifically used to charge the battery to a fully charged state before adjusting the power of the battery to a preset power; and discharge the power of the battery from the fully charged state to the preset power.

[0044] In some possible implementations, the charging and discharging module is specifically configured to charge the target battery cell so that the target battery cell's charge exceeds the charge of the other battery cells by greater than or equal to 20% of the charge in a fully charged state, and less than or equal to 50% of the charge in a fully charged state. For example, the target battery cell's charge exceeds the charge of the other battery cells by 20%, 30%, 40%, or 50% of the charge in a fully charged state.

[0045] In some possible implementations, the control module is further configured to, before charging a target battery cell in the battery, shield a balancing function of a battery management system of the battery.

[0046] In some possible implementations, the control module is further configured to shield an overvoltage protection function of a battery management system of the battery before charging the battery.

[0047] In some possible implementations, the control module is further used to control the charge and discharge module to stop charging the battery when at least one of the following conditions is met: the battery meets a thermal runaway condition; the temperature of the battery reaches a temperature threshold; the charging time of the battery reaches a time threshold; the voltage of the battery reaches a voltage threshold.

[0048] In some possible implementations, the thermal runaway condition includes: the voltage of the battery is greater than or equal to 1V and the temperature rise rate of the battery for three consecutive samples is greater than or equal to 3°C / s, or the battery status information includes fire or explosion; or the voltage drop of the battery exceeds 25% of the initial voltage or the temperature of the battery exceeds a temperature threshold, and the temperature rise rate of the battery is greater than or equal to 1°C / s.

[0049] In some possible implementations, the time threshold is greater than or equal to 4 hours, and / or the temperature threshold is greater than or equal to 300° C., and / or the voltage threshold is greater than or equal to 1.1 times or 1.2 times the charging cut-off voltage of the battery.

[0050] In some possible implementations, the target battery cell includes one or more battery cells, and the multiple battery cells are connected in parallel and / or in series.

[0051] In some possible implementations, the battery includes a battery box or a battery cluster.

[0052] In some possible implementations, the battery is an electrical box, and the target battery cell is located in the middle of the electrical box.

[0053] In some possible implementations, the battery is a battery cluster including multiple electrical boxes, wherein the electrical box where the target battery cell is located is located in the middle of the battery cluster, and the target battery cell is located in the middle of the electrical box where it is located.

[0054] In some possible implementations, the charging and discharging module is specifically configured to perform constant current charging or constant power charging on the battery. The constant current charging current may be greater than or equal to 1C, or the maximum allowable current of the battery.

[0055] In some possible implementations, the control module is further configured to monitor, during the charging and discharging module charging the battery, at least one of the following information about the battery and a monitoring object adjacent to the battery: charging time, voltage, temperature, temperature rise rate, and status information. The status information may include, for example, at least one of the following: expansion, leakage, smoking, fire, explosion, and location of a housing rupture.

[0056] In some possible implementations, the system further includes an insulation monitoring module, and the control module is further configured to control the insulation monitoring module to test the insulation performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0058] FIG1 is a schematic flow chart of a method for triggering battery thermal runaway according to an embodiment of the present application.

[0059] FIG2 is a possible schematic block diagram of a battery according to an embodiment of the present application.

[0060] FIG3 is another possible schematic block diagram of a battery according to an embodiment of the present application.

[0061] FIG4 is a schematic block diagram of a system for triggering battery thermal runaway according to an embodiment of the present application.

[0062] FIG5 is a schematic diagram of the box body of the electrical box according to an embodiment of the present application.

[0063] FIG6 is a schematic diagram showing how the voltage and temperature of thermal runaway vary with SOC according to an embodiment of the present application.

[0064] FIG7 is a schematic diagram showing the change of voltage and temperature over time in thermal runaway according to an embodiment of the present application.

[0065] FIG8 is a schematic diagram of a possible specific testing process of the method shown in FIG1 . DETAILED DESCRIPTION

[0066] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0067] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in this application and in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned figures are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0068] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0069] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0070] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0071] In this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are for illustrative purposes only and do not constitute any limitation on this application.

[0072] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0073] A battery generally refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, in a power system, the battery may include a battery module or battery pack. Typically, the battery also includes a casing to enclose the one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells. For another example, in an energy storage system, the battery may include an electrical box, battery cluster, electrical cabinet, or container.

[0074] Optionally, the battery can be a lithium ion battery, a lithium metal battery, a lead-acid battery, a nickel-cathode battery, a nickel-hydrogen battery, a lithium-sulfur battery, a lithium-air battery, a sodium ion battery or a magnesium ion battery, etc., which is not limited in this application.

[0075] If a battery cell experiences thermal runaway, the temperature inside the cell rises, potentially triggering a chain reaction that could lead to fire or explosion. Thermal runaway can also spread, posing risks to other adjacent batteries. Typically, triggering thermal runaway in a single cell is necessary to test its spread within the battery and analyze battery safety.

[0076] For example, a heating element may be provided inside a battery cell to heat the battery cell so as to trigger thermal runaway of the battery cell.

[0077] For another example, the positive electrode of the power supply can be connected to the negative electrode of the battery cell, and the negative electrode of the power supply can be electrically connected to the shell of the battery cell, so that copper deposition occurs inside the battery cell, triggering an internal short circuit in the battery cell, causing the temperature of the battery cell to rise rapidly, thereby triggering thermal runaway of the battery cell.

[0078] However, methods such as triggering an internal short circuit in a battery cell or installing a heating element inside the battery cell require providing a special battery pack in advance, or requiring specific damage and modification to the battery structure, which makes it difficult to simulate the diffusion behavior of thermal runaway in actual applications.

[0079] To this end, the present application provides a triggering scheme for thermal runaway of a battery, which charges a specific battery cell in the battery until its power level is higher than the power levels of other battery cells in the battery, and then charges the entire battery so that the specific battery cell will undergo thermal runaway due to overcharging before the other battery cells reach the charging cut-off voltage.

[0080] Figure 1 shows a schematic flow chart of a method for triggering battery thermal runaway according to an embodiment of the present application. As shown in Figure 1 , method 300 includes some or all of the following steps.

[0081] In step 310 , a target battery cell in a battery is charged so that the charge of the target battery cell is greater than the charge of other battery cells in the battery.

[0082] In step 320 , when the power level of the target battery cell is greater than the power levels of the other battery cells, the battery is charged.

[0083] The amount of electricity used here is used to indicate the amount of stored charge or energy, and may include, for example, the state of charge (SOC), state of energy (SOE), or capacity, etc. Among them, SOC may refer to the percentage of remaining charge capacity, that is, the ratio of remaining charge capacity to rated capacity, and SOE may refer to the percentage of remaining energy, for example.

[0084] Taking SOC as an example, in step 310, the target battery cell in the battery is first charged until its SOC is greater than the SOC of other battery cells, and then in step 320, the entire battery is charged until the SOC of the target battery cell is too large to cause overcharging, resulting in an abnormality.

[0085] Here, the abnormality includes, for example, thermal runaway of the target battery cell. If, during charging or use, the voltage and / or temperature of the target battery cell rises due to various reasons and cannot be effectively controlled, resulting in safety issues such as overheating, combustion, fire, or explosion, the target battery cell can be considered to have experienced thermal runaway. Optionally, a thermal runaway condition can be set, and if the target battery cell reaches the thermal runaway condition, it is determined that the target battery cell has experienced thermal runaway.

[0086] For example, for an energy storage battery, the thermal runaway condition may include: the battery voltage is greater than or equal to 1V and the battery temperature rise rate for three consecutive samples is greater than or equal to 3°C / s, or the battery status information includes fire or explosion.

[0087] For another example, for a power battery, thermal runaway conditions may include: a) a battery voltage drop exceeding 25% of the initial voltage; b) the battery temperature exceeding a temperature threshold, i.e., the specified maximum operating temperature; and c) a battery temperature rise rate greater than or equal to 1°C / s, such as a temperature rise rate greater than or equal to 1°C / s for more than 3 seconds. Thermal runaway is determined to have occurred when a) and c) occur, or b) and c) occur.

[0088] It is understood that the target battery cell is a battery cell selected from multiple battery cells in the battery to trigger thermal runaway. The target battery cell can include one or more battery cells to meet various testing requirements. In the case where the target test cell unit includes multiple battery cells, the multiple battery cells are connected in parallel and / or in series.

[0089] For example, the target battery cell may be one of the multiple battery cells of the battery; for another example, the target battery cell may include several battery cells connected in series; for another example, the target battery cell may include several battery cells connected in parallel, such as including one minimum parallel unit, or including multiple minimum parallel units connected in series.

[0090] Other battery cells refer to battery cells other than the target battery cell. Optionally, the power of other battery cells may refer to the average power of other battery cells, the power of a certain battery cell, or the power of the battery cell with the highest power among other battery cells.

[0091] In an embodiment of the present application, the target battery cell is charged to a level higher than that of other battery cells in the battery. By creating a power imbalance between the target battery cell and other battery cells, during the charging of the entire battery, before other batteries reach the charging cut-off voltage, the target battery cell can experience thermal runaway due to overcharging, while other battery cells operate within a normal power range.

[0092] Compared to a solution that triggers thermal runaway by providing a heating element inside a battery cell, or a solution that triggers thermal runaway by connecting the positive electrode of a power source to the negative electrode of a battery cell and electrically connecting the negative electrode of the power source to the housing of the battery cell, using method 300 in an embodiment of the present application to trigger thermal runaway of a target battery cell due to overcharging has the following advantages:

[0093] First, there is no need to prepare special battery cells or batteries during the production process, nor is there any need for complex battery modification, so the testing process is not restricted by time and space and can be widely used for random inspection of batteries.

[0094] Secondly, it will not damage the structure of the battery, reducing the impact on the battery's airtightness and high-voltage electrical connections;

[0095] Finally, it is possible to simulate thermal runaway behavior during dynamic charging.

[0096] Method 300 is applicable to various types of lithium-ion batteries, and the test results are stable and reliable.

[0097] In the embodiment of the present application, the battery to be tested may be a battery pack or battery module in a power system, or an electrical box, battery cluster, electrical cabinet or container in an energy storage system.

[0098] As an example, assume that it is necessary to simulate the spread of thermal runaway between electrical boxes, that is, the impact of thermal runaway on adjacent electrical boxes. As shown in Figure 2, the battery to be tested can be an electrical box. Assuming that the target battery cell includes one battery cell, the battery cluster 1 shown in Figure 2 includes multiple electrical boxes. For example, as shown in Figure 2, the number of electrical boxes in battery cluster 1 is N, including electrical box 10-1, electrical box 10-2, ..., electrical box 10-I, ..., electrical box 10-(N-1), and electrical box 10-N, where I and N are positive integers and I is less than or equal to N. In which, each electrical box includes multiple battery cells connected in parallel and / or in series. For example, as shown in Figure 2, the number of battery cells in each electrical box is M, including battery cell 100-1, battery cell 100-2, battery cell 100-3,..., battery cell 100-J,..., battery cell 100-(M-2), battery cell 100-(M-1), battery cell 100-M, J and M are positive integers and J is less than or equal to M.

[0099] You can select any electrical box in battery cluster 1 and any battery cell in that box as the target battery cell to trigger thermal runaway. For example, you can select electrical box 10-I located in the middle of battery cluster 1 and battery cell 100-J located in the middle of electrical box 10-I as the target battery cell to trigger thermal runaway.

[0100] During the test, it is necessary to charge the battery cell 100-J until its charge is higher than the charge of other battery cells in the battery, and charge the entire battery so that the battery cell 100-J will experience thermal runaway due to overcharging before the other battery cells reach the charging cut-off voltage.

[0101] If thermal runaway occurs in battery cell 100-J, it could spread to other adjacent electrical boxes 10-I. By observing the status of these adjacent electrical boxes, we can determine the extent of the thermal runaway spread between these boxes. Hereinafter, these adjacent electrical boxes are referred to as monitoring targets.

[0102] Here, the middle of the battery cluster 1 refers to the electrical box located at or near the center position among the multiple electrical boxes in the battery cluster 1, such as the electrical box 10-I located in the middle of the battery cluster 1. Referring to the electrical box arrangement shown in Figure 2, I can be, for example, N / 2, (N-1) / 2 or (N+1) / 2; the middle of the electrical box 10-I refers to the battery cell located at the center position among the multiple battery cells of the electrical box 10-I, such as the battery cell 100-J in the middle of the electrical box 10-I. Referring to the battery cell arrangement shown in Figure 2, J can be, for example, M / 2, (M-1) / 2 or (M+1) / 2.

[0103] In Figure 2, the positional relationship between the battery cells and the positional relationship between the electrical boxes are only examples. In actual applications, the battery cells can be arranged in other ways within the electrical box, and the electrical boxes can also be arranged in other ways to form a battery cluster.

[0104] Similarly, assuming it is necessary to simulate the spread of thermal runaway between battery clusters, that is, the impact of thermal runaway on adjacent battery clusters, the battery to be tested can be a battery cluster, as shown in Figure 3. For example, assuming the target battery cell consists of a single battery cell, the electrical cabinet 2 shown in Figure 3 includes multiple battery clusters.

[0105] For example, as shown in (a) in Figure 3, the electrical cabinet 2 includes 6 battery clusters, namely battery cluster 1-1, battery cluster 1-2, battery cluster 1-3, battery cluster 1-4, battery cluster 1-5 and battery cluster 1-6. The 6 battery clusters are arranged in double rows, wherein the target battery cell is located in battery cluster 1-5, for example, in the electrical box in the middle of battery cluster 1-5, and is located in the middle of the electrical box.

[0106] During the test, it is necessary to charge the target battery cell in battery cluster 1-5 to a level higher than that of other battery cells in battery cluster 1-5, and charge the entire battery cluster 1-5 so that the target battery cell in battery cluster 1-5 will experience thermal runaway due to overcharging before the other battery cells in battery cluster 1-5 reach the charging cut-off voltage.

[0107] At this time, battery clusters 1-2, 1-4, and 1-6 adjacent to battery cluster 1-5 are monitored. By observing the status of the monitored objects, the spread of thermal runaway between the battery clusters can be determined.

[0108] For another example, as shown in (b) in Figure 3, the electrical cabinet 2 includes three battery clusters, namely battery cluster 1-1, battery cluster 1-2 and battery cluster 1-3. The three battery clusters are arranged in a single row, wherein the target battery cell is located in battery cluster 1-2, for example, in the electrical box in the middle of battery cluster 1-2, and is located in the middle of the electrical box.

[0109] During the test, it is necessary to charge the target battery cell in battery cluster 1-2 to a level higher than that of other battery cells in battery cluster 1-2, and charge the entire battery cluster 1-2 so that the target battery cell in battery cluster 1-2 will experience thermal runaway due to overcharging before the other battery cells in battery cluster 1-2 reach the charging cut-off voltage.

[0110] At this time, battery clusters 1-1 and 1-3, which are adjacent to battery cluster 1-2, are monitored. By observing the status of the monitored objects, it is possible to determine whether thermal runaway is spreading between the battery clusters.

[0111] For another example, as shown in (c) in Figure 3, the electrical cabinet 2 includes 6 battery clusters, namely battery cluster 1-1, battery cluster 1-2, battery cluster 1-3, battery cluster 1-4, battery cluster 1-5 and battery cluster 1-6. The 6 battery clusters are arranged in channels, wherein the target battery cell is located in battery cluster 1-5, for example, in the electrical box in the middle of battery cluster 1-5, and is located in the middle of the electrical box.

[0112] During the test, it is necessary to charge the target battery cell in battery cluster 1-5 to a level higher than that of other battery cells in battery cluster 1-5, and charge the entire battery cluster 1-5 so that the target battery cell in battery cluster 1-5 will experience thermal runaway due to overcharging before the other battery cells in battery cluster 1-5 reach the charging cut-off voltage.

[0113] At this time, battery clusters 1-2, 1-4, and 1-6 adjacent to battery cluster 1-5 are monitored. By observing the status of the monitored objects, the spread of thermal runaway between the battery clusters can be determined.

[0114] In the embodiment of the present application, selecting the electrical box in the middle of the battery cluster and / or selecting the battery cell in the middle of the electrical box as the target battery cell can make the spread of thermal runaway more uniform, thereby making the test results more comprehensive and stable.

[0115] The battery cluster where the target battery cell is located and the monitoring objects arranged adjacent to the battery cluster are simulated and arranged according to the actual installation conditions in the prefabricated cabin. The arrangement of the battery clusters shown in FIG3 is only an example.

[0116] It can be understood that in the embodiment of the present application, since it is necessary to examine the impact of thermal runaway of a battery on other adjacent batteries, the monitoring object arranged adjacent to the battery where the target battery cell is located may be a real battery, or it may not be a real battery but a simulated structure or device used to replace the real battery, for example, only including parts such as the battery box.

[0117] For example, as shown in Figure 3, in (a) and (c) of Figure 3, battery cluster 1-5 is a real battery cluster, which includes target battery cells, and the monitoring objects and battery cluster 1-2, battery cluster 1-4 and battery cluster 1-6 can be real battery clusters that are the same as battery cluster 1-5, or other structures or devices used to replace battery cluster 1-2, battery cluster 1-4 and battery cluster 1-6.

[0118] For another example, as shown in FIG3 , in FIG3 (b), battery cluster 1-2 is a real battery cluster, which includes target battery cells, and the monitoring objects, namely battery cluster 1-1 and battery cluster 1-3, can be real battery clusters identical to battery cluster 1-2, or other structures or devices used to replace battery cluster 1-1 and battery cluster 1-3.

[0119] In some embodiments, the method 300 may be executed by a system for triggering battery thermal runaway, as shown in Figure 4 , the system 200 includes a battery to be tested 210, a charge and discharge module 220, and a control module 230. The battery 210 includes a plurality of battery cells.

[0120] The battery 210 may be an electrical box, such as the electrical box 10-1 shown in FIG1 , or a battery cluster, such as the battery cluster 1-5, battery cluster 1-2, and battery cluster 1-5 shown in FIG3 (a), (b), and (c), respectively. Of course, the battery 210 may also be a battery unit at any level, such as a battery pack, a battery module, an electrical cabinet, or a container.

[0121] As an example, as shown in Figure 4, any two of the battery 210, the charge and discharge module 220 and the control module 230 can communicate through the communication line 201, such as transmitting instructions and information. Optionally, the system 200 also includes a thermostat 240, which is used to keep the temperature of the battery 210 constant during the test to reduce the impact of temperature changes on the test results. At this time, instructions and information can also be transmitted between the control module 230 and the thermostat 240 through the communication line 201. There is a high-voltage connecting line 202 between the charge and discharge module 220 and the battery 210, and the charge and discharge module 220 can charge and / or discharge the battery 210 through the high-voltage connecting line 202.

[0122] Optionally, the method 300 described above may be executed by the control module 230. Specifically, the control module 230 is configured to control the charge and discharge module 220 to charge a target battery cell in the battery 210 so that the charge level of the target battery cell is greater than the charge levels of other battery cells in the battery 210, and to control the charge and discharge module 230 to charge the battery 210.

[0123] In some embodiments, the charge-discharge module 220 may include a first charge-discharge device and a second charge-discharge device, wherein the first charge-discharge device is used to charge and discharge a target battery cell in the battery 210, and the second charge-discharge device is used to charge and discharge the entire battery 210. In other words, the control module 230 may control the first charge-discharge device to charge and discharge the target battery cell, and control the second charge-discharge device to charge and discharge the battery 210.

[0124] The first charging and discharging device may be, for example, a charging and discharging machine with a larger range, such as a charging and discharging machine with a current between 50A and 500A and a voltage greater than 600V. The second charging and discharging device may be, for example, a charging and discharging machine with a smaller range, such as a charging and discharging machine with a current between 2A and 10A and a voltage less than 60V.

[0125] By selecting the first charging and discharging device and the second charging and discharging device adapted to the target battery cell and the battery 210 respectively, the target battery cell and the battery 210 can be effectively charged or discharged respectively, thereby improving the charging and discharging performance.

[0126] Of course, the same charging and discharging device may also be used to charge and discharge the battery 210 and the target battery cell, and this application does not limit this.

[0127] The current used by the first charging and discharging device to charge the target battery cell may be, for example, less than or equal to 5 A, and further, less than or equal to 2 A, so as to meet the charging capacity of most short-range charging and discharging machines.

[0128] The second charging and discharging device can exchange information with battery 210, for example, with the battery management system of battery 210. However, the charging and discharging module 220 does not need to exchange information with the target battery cell, as long as it can collect information about the battery's voltage and current. Optionally, the first charging and discharging device has the following functions: controlling the on / off of the charging and discharging circuit, regulating the output voltage and current, and monitoring information such as the battery's voltage and current.

[0129] When the control module 230 controls the charge and discharge module 220 to charge the target battery cell, the control module 230 can send a first charge and discharge instruction to the first charge and discharge device, and the first charge and discharge device charges or discharges the target battery cell in response to the first charge and discharge instruction; when the control module 230 controls the charge and discharge module 220 to charge the battery 210, the control module 230 can send a second charge and discharge instruction to the second charge and discharge device, and the second charge and discharge device charges or discharges the battery 210 in response to the second charge and discharge instruction.

[0130] The ports of the wires of the second charging and discharging device should match the design of the charging and discharging ports of the battery 210 to achieve electrical connection between the second charging and discharging device and the battery 210. The ports of the wires of the first charging and discharging device need to be able to achieve stable connection with the electrode terminals of the battery cells.

[0131] For example, in some embodiments, during the process of the first charge and discharge device charging and discharging the target battery cell, the end of the positive wire of the first charge and discharge device is pasted between the positive electrode terminal of the target battery cell, and the end of the negative wire of the first charge and discharge device is pasted between the negative electrode terminal of the target battery cell.

[0132] For example, conductive tape or conductive glue can be used to stick the end of the positive wire of the first charging and discharging device to the positive electrode terminal of the target battery cell, and the end of the negative wire of the first charging and discharging device to the negative electrode terminal of the target battery cell. This connection method can save costs.

[0133] Alternatively, in other embodiments, during the process of the first charging and discharging device charging and discharging the target battery cell, the end of the positive electrode wire of the first charging and discharging device contacts the positive electrode terminal of the target battery cell through the pressing of the pressing mechanism, and the end of the negative electrode wire of the first charging and discharging device contacts the negative electrode terminal of the target battery cell through the pressing of the pressing mechanism.

[0134] Since the pressing mechanism is used to directly press the end of the wire and the electrode terminal of the target battery cell together, the contact reliability between the wire and the electrode terminal is improved and the probability of poor contact between the wire and the electrode terminal during the test is reduced.

[0135] In addition, other connection methods that can form a current loop between the target battery cell and the first charging and discharging device and keep the loop stable can also be used in the test process to connect the first charging and discharging device and the target battery cell.

[0136] The control module 230 can be, for example, a monitoring computer, which can control the charge and discharge module 220 to perform the charge and discharge functions. The charge and discharge module 220 can also transmit the collected voltage, current and other information to the monitoring computer, and the monitoring computer can display the voltage, current and other information of the target battery cell and battery, as well as the monitoring information of other adjacent batteries, to the tester through its display interface.

[0137] The monitoring computer can also directly collect the temperature information of the target battery cells and batteries, obtain the temperature rise rate, and present information such as temperature and temperature rise rate to the tester through its display interface.

[0138] Alternatively, the temperature of the target battery cell can be collected using a temperature sensor disposed on the target battery cell. For example, the temperature sensor on each target battery cell is located closest to the positive and negative electrode terminals on the battery cell, and the distance between the temperature sensor and the positive electrode terminal is equal to the distance between the temperature sensor and the negative electrode terminal, thereby improving the stability and accuracy of the temperature collected by the temperature sensor. The temperature sensor can be, for example, a temperature sampling line.

[0139] In some embodiments, as shown in FIG5 , an electrical box 10 includes a battery 210 and a housing 101 for accommodating the battery 210. The battery 210 includes a target battery cell. The housing 101 includes a first housing portion 1011 and a second housing portion 1012 that interlock with each other. The electrode terminals of the battery cells in the battery 210 all face the first housing portion 1011. During charging of the target battery cell, the first housing portion 1011 is removed to connect the electrode terminals to the first charging and discharging device. That is, the first housing portion 1011 is removed from the second housing portion 1012 to expose the battery cell within the second housing portion 1012 without changing other structures within the battery 210.

[0140] Specifically, during the test process, before step 310, the first housing 1011 needs to be removed to expose the electrode terminals of the multiple battery cells within the housing 101, and the conductive end of the first charging and discharging device needs to be connected to the electrode terminals of the target battery cell. For example, the end of the positive lead of the first charging and discharging device is attached to the positive electrode terminal of the target battery cell, and the end of the negative lead of the first charging and discharging device is attached to the negative electrode terminal of the target battery cell. In another example, the pressing mechanism is controlled to press the end of the positive lead of the first charging and discharging device to the positive electrode terminal of the target battery cell, and the pressing mechanism is controlled to press the end of the negative lead of the first charging and discharging device to the negative electrode terminal of the target battery cell. It should be noted that during this process, the electrical connector of the target battery cell should not be damaged, such as by tilting the busbar.

[0141] After the connection between the first charging and discharging device and the target battery cell is completed, in step 310 , the first charging and discharging device is controlled to charge the target battery cell so that the power of the target battery cell exceeds the power of other battery cells.

[0142] As can be seen, only the first housing portion 1011 of the housing 101 needs to be opened and the wires of the first charging and discharging device connected to the electrode terminals of the target battery cell. After the first charging and discharging device completes charging of the target battery cell, the connection between the target battery cell and the first charging and discharging device can be disconnected, and the first housing portion 1011 can be re-closed on the second housing portion 1012 to restore the battery to its actual state. During this process, the structure of the battery 210 is not damaged, and the airtightness of the battery 210 and the high-voltage connector 103 are not affected.

[0143] It can be understood that the charging and discharging device of the embodiment of the present application can be used to charge and / or discharge the battery. It can be a device with only a charging function, a device with only a discharging function, or a device with both charging and discharging functions.

[0144] As shown in FIG5 , the first housing portion 1101 is a hollow structure with an opening, and the second housing portion 1102 is a flat plate structure. The two interlock to form a storage space for accommodating battery cells. In other implementations, the first housing portion 1101 and the second housing portion 1102 can both be hollow structures with openings, or the first housing portion 1101 can be a flat plate structure and the second housing portion 1102 can be a hollow structure with an opening.

[0145] In some embodiments, in step 320, the battery can be charged with a constant current or a constant power. For power batteries, constant current charging can usually be used to charge them to reduce the risks caused by charging; for energy storage batteries, constant power charging can usually be used to charge them to improve charging efficiency. Therefore, in step 310, if the battery 210 is used in a power system, the battery can be charged with a constant current. For example, the current used for constant current charging can be greater than or equal to 1C, such as 1C, 2C, 3C, etc., or the current used for constant current charging is equal to the maximum allowable current of the battery; if the battery is used in an energy storage system, the battery can be charged with a constant power to meet the application of the battery in different scenarios.

[0146] In step 310, if the target battery cell is charged to a level that exceeds the levels of other battery cells by a large amount, thermal runaway of the target battery cell may be more likely to occur when the entire battery is charged in the subsequent step 320; whereas if the target battery cell is charged to a level that exceeds the levels of other battery cells by a small amount, the risk of premature overcharging of the target battery cell when charging the target battery cell in step 310 may be reduced.

[0147] To this end, in some embodiments, in step 310, the target battery cell can be charged until its charge exceeds the charge of other battery cell units, and the charge difference between the charge of the target battery cell and the charge of other battery cells is within a suitable range, for example, it can be greater than or equal to 15% of the charge in the fully charged state and less than or equal to 70% of the charge in the fully charged state. Further, for example, it can be greater than or equal to 20% of the charge in the fully charged state and less than or equal to 50% of the charge in the fully charged state. This range is applicable to most lithium iron phosphate (such as LiFePO4 (also referred to as LFP) chemical system batteries and ternary material (Ni-Co-Mn, NCM) chemical system batteries. As an example, the charge of the target battery cell may exceed the charge of other battery cells by 20%, 30%, 40%, 50% or 60% of the charge in the fully charged state.

[0148] Taking SOC as an example, in step 310, the target battery cell may be charged until its SOC is at least 20% higher than the SOC of other battery cells and not more than 50%. Alternatively, the SOC of the target battery cell is 20% or 40% higher than the SOC of other battery cells.

[0149] In this way, the risk of overcharging the target battery cell can be reduced during the charging process of the target battery cell, and thermal runaway of the target battery cell can be caused during the charging process of the entire battery, thereby achieving effective testing of the battery.

[0150] In some embodiments, before step 310, i.e., before charging the target battery cell in the battery, method 300 further includes adjusting the battery's charge to a preset charge. This preset charge is less than the battery's charge when fully charged. This ensures consistency in the initial state of each battery cell in the battery. This preset charge can serve as a standard state for the sample being tested, facilitating standardized testing procedures.

[0151] In such an initial state, the target battery cell may be charged to a certain extent exceeding the preset power level. For example, the target battery cell may be charged until its SOC exceeds the preset power level by 20% to 50% of the power level in the fully charged state.

[0152] In some embodiments, the preset power level can be set to be less than or equal to 85% of the power level in a fully charged state. Furthermore, the preset power level can be set to be less than or equal to 70% of the power level in a fully charged state, thereby reducing the risk of overcharging the target battery cell during charging of the target battery cell in step 310. For example, the preset power level can be set to 50%, 60%, 70%, or 80% of the power level in a fully charged state.

[0153] Furthermore, in some embodiments, before adjusting the power level of the battery 210 to the preset power level, the method 300 further includes: charging the battery to a full charge state, for example, charging the battery to a full charge state at a rated power, i.e., initializing charging. In other words, the battery may be first charged to a full charge state and then discharged to the preset power level to adjust the initial power level of the battery. Of course, the battery may also be charged directly from 0 or another value to the preset power level without fully charging the battery.

[0154] The preset power and / or the power difference between the target battery cell and other battery cells can be set so that when the target battery cell has thermal runaway, the other battery cells are close to being fully charged, thereby enhancing the test effect.

[0155] Taking SOC as an example, assuming the preset charge is 50%, the charge difference between the target battery cell and the other battery cells is 40%. After adjusting the battery's SOC to 50%, the target battery cell in the battery is charged to an SOC of 90%, which is 40% higher than the preset charge. At this time, the difference between the SOC of the target battery cell and the SOC of the other battery cells in the battery is 40%. Generally, thermal runaway may occur when the SOC of the target battery cell reaches around 110% or 120%. During the charging process of the entire battery, when the target battery cell experiences thermal runaway, the SOC of the other battery cells in the battery is around 80%, close to a fully charged state. In this way, the change in battery status when thermal runaway occurs and spreads is more obvious and easier to monitor.

[0156] In some embodiments, before step 310 , ie, before charging the target battery cell in the battery, the method 300 further includes: disabling a balancing function of a battery management system of the battery.

[0157] The battery balancing function is to adjust the voltage difference between battery cells or the voltage difference between battery cell groups to an appropriate range, so that each battery cell maintains a substantially identical state during use, reducing the risk of overcharge or over-discharge. Because the embodiment of the present application needs to trigger thermal runaway of the target battery cell due to overcharge, shielding the balancing function of the battery management system can reduce the risk of the target battery cell being unable to trigger thermal runaway due to the equalization of the power difference between the target battery cell and other battery cells, thereby reducing the impact of the balancing function on the testing process.

[0158] In some embodiments, before step 320 , ie, before charging the battery 210 , the method 300 further includes: shielding an overvoltage protection function of a battery management system of the battery.

[0159] Since excessive voltage may damage the battery, the battery's overvoltage protection function can reduce the probability of abnormal or excessive output voltage during the charging and discharging process. For example, when it is detected that the battery voltage exceeds the rated voltage, the charge and discharge circuit can be disconnected to prevent the voltage from continuing to rise. Since the embodiment of the present application needs to trigger thermal runaway of the target battery cell due to overcharging, it is necessary to disable the overvoltage protection function to reduce the risk of the charging circuit being disconnected before the target battery cell experiences thermal runaway, resulting in the termination of the test process. This reduces the impact of the overvoltage protection function on the test process.

[0160] By setting appropriate test stop conditions, it is possible to meet test requirements while avoiding unnecessary consumption caused by aimless testing. To this end, in some embodiments, method 300 further includes: stopping charging the battery when at least one of the following conditions is met: the battery meets a thermal runaway condition; the battery temperature reaches a temperature threshold; the battery charging time reaches a time threshold; or the battery voltage reaches a voltage threshold.

[0161] It is understood that the thermal runaway condition can adopt the definition of thermal runaway in relevant standards, that is, the thermal runaway trigger determination conditions in relevant battery standards. Using the thermal runaway conditions in relevant standards to determine whether a battery has experienced thermal runaway facilitates the integration of method 300 with existing standards and promotes the promotion of method 300.

[0162] For example, for an energy storage battery, the thermal runaway condition may include: the battery voltage is greater than or equal to 1V and the battery temperature rise rate for three consecutive samples is greater than or equal to 3°C / s, or the battery status information includes fire or explosion.

[0163] For another example, for a power battery, thermal runaway conditions may include: a) a battery voltage drop exceeding 25% of the initial voltage; b) the battery temperature exceeding a temperature threshold, i.e., the specified maximum operating temperature; and c) a battery temperature rise rate greater than or equal to 1°C / s, such as a temperature rise rate greater than or equal to 1°C / s for more than 3 seconds. Thermal runaway is determined to have occurred when a) and c) occur, or b) and c) occur.

[0164] Figures 6 and 7 illustrate the voltage and temperature changes associated with thermal runaway. These figures use an LFP battery as an example. Using voltage and temperature rise rate as conditions, thermal runaway is considered to have occurred if the battery voltage suddenly drops below 1V during charging, and the temperature rise rate is greater than or equal to 3°C / s for three consecutive periods. As shown in Figure 6, the SOC of the target battery cell is approximately 112%, and as shown in Figure 7, the charging time is approximately 896 seconds. This can also be accompanied by battery fire and / or explosion.

[0165] The time threshold can be set to be greater than or equal to 4 hours, for example; the temperature threshold can be set to be greater than or equal to 300°C, for example; and the preset multiple can be set to be greater than or equal to a predetermined multiple of the battery's charge cutoff voltage, for example, the predetermined multiple can be between 1 and 1.2, such as 1, 1.1, or 1.2. For batteries with an LFP chemistry, the preset multiple can be 1.2, for example; and for batteries with a ternary chemistry, the preset multiple can be 1.1.

[0166] If the battery does not reach the above-mentioned thermal runaway condition, but the charging time reaches a time threshold, such as 4 hours, the test can be stopped.

[0167] If the battery does not reach the above-mentioned thermal runaway condition, but the temperature of the battery reaches a temperature threshold, such as 300° C., the test may be stopped.

[0168] If the battery does not reach the above-mentioned thermal runaway condition, but the battery voltage reaches a preset multiple of the charge cut-off voltage, such as 1.2 times, the test can be stopped.

[0169] By reasonably setting the thermal runaway conditions and setting test stop conditions such as charging time, battery temperature, and voltage, the test process can be effectively controlled without affecting the test results.

[0170] In some embodiments, method 300 further includes: during charging of the battery, monitoring at least one of the following information of the battery and a monitoring object adjacent to battery 210: charging time, voltage, temperature, temperature rise rate, and status information. The status information may include, for example, at least one of the following: expansion, leakage, smoking, fire, explosion, and location of a case rupture.

[0171] Based on the previous description, during the battery charging process, the battery's charging time, voltage, current, temperature, and temperature rise rate are recorded. The voltage, current, temperature, and temperature rise rate of the monitoring object located adjacent to the battery are also recorded. Test phenomena, including swelling, leakage, smoke, fire, explosion, and the location of the case rupture, are also recorded. By recording this battery information and time delay during charging, it is possible to promptly determine whether thermal runaway has been triggered.

[0172] When the target battery cell reaches the above-mentioned thermal runaway conditions, for example, taking the energy storage battery as an example, the battery voltage is greater than or equal to 1V and the battery temperature rise rate for three consecutive samples is greater than or equal to 3°C / s, or the battery status information includes fire or explosion, or the battery temperature reaches a temperature threshold, or the charging time reaches a time threshold, or the battery voltage reaches a preset multiple of its charge cut-off voltage, then stop charging the battery and observe for a certain period of time, such as greater than or equal to 8 hours, record the battery voltage, temperature, and temperature rise rate during the charging time, and record the test phenomena, including the location of expansion, leakage, smoking, fire, explosion, and box rupture.

[0173] When judging whether thermal runaway has spread to the monitored object, that is, whether the monitored object has also experienced thermal runaway, the above-mentioned thermal runaway conditions can be used as conditions for whether thermal runaway has occurred in the monitored object. For example, the voltage of the monitored object is greater than or equal to 1V and the temperature rise rate of three consecutive samples is greater than or equal to 3°C / s, or the monitored object catches fire or explodes.

[0174] It is understandable that after triggering thermal runaway of the target battery cell or stopping the test, the battery itself and nearby monitored objects may not necessarily show obvious thermal runaway phenomena. Therefore, in some embodiments, method 300 also includes: testing the insulation performance of the battery.

[0175] The insulation performance of the battery can reduce the risk of leakage in the high-voltage circuit. When the battery swells, leaks, smokes, catches fire, explodes, or the case ruptures, the insulation performance of the battery is likely to have been destroyed. However, when thermal runaway of the target battery cell is triggered or the test is stopped, if no obvious thermal runaway phenomenon is observed in the monitoring of the battery itself and its vicinity, the insulation performance test of the battery can better understand the risks caused by thermal runaway, making the battery test more comprehensive and reliable.

[0176] After the test is completed, it is necessary to disconnect the battery from the corresponding charging and discharging device, remove the data sampling line and remove the battery.

[0177] Fig. 8 is a schematic diagram of a possible specific test process of method 300. As shown in Fig. 8, the test process includes part or all of the following steps.

[0178] In step 301 , the SOC of the battery is adjusted to a preset power level, such as 50% SOC.

[0179] In step 302 , the battery balancing function is disabled.

[0180] In step 303 , the target battery cell in the battery is charged so that the SOC of the target battery cell is higher than the power levels of other battery cells in the battery, for example, the target battery cell is charged to 90% SOC.

[0181] Before charging the target battery cell, the first box body 1011 of the box body 101 needs to be removed, and the positive and negative electrode wire ends of the first charging and discharging device need to be connected to the positive and negative electrode terminals of the target battery cell, respectively.

[0182] After charging of the target battery cell is completed, the first box portion 1011 is covered on the second box portion 1012 to keep the battery state the same as that in actual use.

[0183] In step 304 , the overvoltage protection function of the battery is disabled.

[0184] In step 305 , the entire battery is charged.

[0185] In addition, during the charging process, the charging time, voltage, current, temperature, and temperature rise rate of the battery are recorded, and the voltage, current, temperature, and temperature rise rate of the monitoring object set adjacent to the battery are recorded, and the test phenomena are recorded, including the location of expansion, leakage, smoke, fire, explosion, and box rupture.

[0186] Before charging the battery, the ends of the positive and negative lead wires of the second charging and discharging device need to be connected to the positive and negative electrodes of the battery, respectively.

[0187] In step 306 , the battery is monitored to see if it has reached a thermal runaway condition.

[0188] If a thermal runaway condition is reached, for example, the battery voltage suddenly drops below 1 V and the temperature rise rate is greater than or equal to 3° C. / s for three consecutive times, or the battery catches fire or explodes, step 307 is executed.

[0189] In addition, step 307 is also executed when the test stop condition is met, for example, when the charging time reaches 4 hours, or the battery temperature reaches 300° C., or the battery voltage reaches 1.2 times its charge cut-off voltage.

[0190] In step 307 , charging of the battery is stopped.

[0191] Observe for 8 hours, record the battery voltage, temperature, temperature rise rate during charging time, and record the test phenomena, including expansion, leakage, smoking, fire, explosion, and the location of box rupture.

[0192] The present application also provides a system for triggering battery thermal runaway, which system may be, for example, the system 200 shown in FIG4 , and may include a battery 210, a charge and discharge module 220, and a control module 230. The battery 210 includes a target battery cell, wherein the control module 230 is configured to control the charge and discharge module 220 to charge the target battery cell in the battery 210 so that the charge level of the target battery cell is greater than the charge levels of other battery cells in the battery, and to control the charge and discharge module 230 to charge the battery when the charge level of the target battery cell is greater than the charge levels of other battery cells.

[0193] In some embodiments, the charge and discharge module 220 includes a first charge and discharge device and a second charge and discharge device, wherein the first charge and discharge device is used to charge and discharge the target battery cell, and the second charge and discharge device is used to charge and discharge the battery 210 .

[0194] In some embodiments, the target battery cell is housed in a box body, which includes a first box body portion and a second box body portion that are interlocked with each other, and the electrode terminal of the target battery cell faces the first box body portion, wherein, during the process of the first charging and discharging device charging the target battery cell, the first box body portion is in a removed state to connect the electrode terminal to the first charging and discharging device.

[0195] In some embodiments, the end of the positive lead of the first charge and discharge device is attached to the positive electrode terminal of the target battery cell, and the end of the negative lead of the first charge and discharge device is attached to the negative electrode terminal of the target battery cell.

[0196] In some embodiments, the end of the positive electrode wire of the first charging and discharging device is pressed by a pressing mechanism and contacts the positive electrode terminal of the target battery cell, and the end of the negative electrode wire of the first charging and discharging device is pressed by the pressing mechanism and contacts the negative electrode terminal of the target battery cell.

[0197] In some embodiments, the charge-discharge module 220 is further configured to adjust the charge level of the battery 210 to a preset charge level before charging the target battery cell in the battery 210. The preset charge level is less than the charge level of the battery 210 when fully charged. For example, the preset charge level is less than or equal to 85% of the charge level when fully charged. For example, the preset charge level is 50%, 60%, 70%, or 80% of the charge level when fully charged.

[0198] In some embodiments, the charge and discharge module 220 is specifically used to charge the battery 210 to a fully charged state before adjusting the power of the battery 210 to a preset power; and discharge the power of the battery 210 from the fully charged state to the preset power.

[0199] In some embodiments, the charge and discharge module 220 is specifically configured to charge the target battery cell so that the target battery cell's charge exceeds the charge of the other battery cells by greater than or equal to 15% of the charge in a fully charged state and less than or equal to 70% of the charge in a fully charged state. For example, the target battery cell's charge exceeds the charge of the other battery cells by 20%, 30%, 40%, or 50% of the charge in a fully charged state.

[0200] In some embodiments, the control module 230 is further configured to shield a balancing function of a battery management system of the battery 210 before charging a target battery cell in the battery 210 .

[0201] In some embodiments, the control module 230 is further configured to shield an overvoltage protection function of a battery management system of the battery 210 before charging the battery 210 .

[0202] In some embodiments, the control module 230 is also used to control the charge and discharge module 220 to stop charging the battery 210 when at least one of the following conditions is met: the battery 210 meets the thermal runaway condition; the temperature of the battery 210 reaches the temperature threshold; the charging time of the battery 210 reaches the time threshold; the voltage of the battery 210 reaches the voltage threshold.

[0203] The thermal runaway condition may include, for example: the voltage of the battery 210 is greater than or equal to 1V and the temperature rise rate of the battery 210 for three consecutive samples is greater than or equal to 3°C / s, or the status information of the battery 210 includes fire or explosion.

[0204] The time threshold may be greater than or equal to 4 hours, for example; the temperature threshold may be greater than or equal to 300° C., for example; and the voltage threshold may be greater than or equal to 1.2 times the charge cut-off voltage of the battery 210 .

[0205] In some embodiments, the target battery cell includes one or more battery cells, and the multiple battery cells are connected in parallel and / or in series.

[0206] In some embodiments, battery 210 includes an electrical box or battery pack.

[0207] In some embodiments, the battery 210 is an electrical box, and the target battery cell is located in the middle of the electrical box.

[0208] In some embodiments, the battery 210 is a battery cluster including multiple electrical boxes. The electrical box where the target battery cell is located is located in the middle of the battery cluster, and the target battery cell is located in the middle of the electrical box where it is located.

[0209] In some embodiments, the electrical quantity includes any one of SOC, SOE, and capacity.

[0210] In some embodiments, the charge and discharge module 220 is specifically configured to perform constant current charging or constant power charging on the battery 210 , wherein the current of the constant current charging may be greater than or equal to 1C, or the maximum allowable current of the battery 210 .

[0211] In some embodiments, the control module 230 is further configured to monitor at least one of the following information about the battery 210 and a monitoring object adjacent to the battery 210 during charging of the battery 210 by the charge / discharge module 220: charging time, voltage, temperature, temperature rise rate, and status information. The status information may include, for example, at least one of the following: expansion, leakage, smoking, fire, explosion, and location of a housing rupture.

[0212] In some embodiments, the system 200 further includes an insulation monitoring module, and the control module 230 is further configured to control the insulation monitoring module to test the insulation performance of the battery 210 .

[0213] It should be understood that the specific details of the system 200 can be referred to the aforementioned description of the method 300, and for the sake of brevity, they are not repeated here.

[0214] This application also provides a battery testing device, including a processor configured to execute computer instructions stored in a memory, so that the testing device implements the contents executed by the control module 230 in method 300 described in at least some of the above embodiments. Optionally, the testing device may also include a memory for storing the computer instructions. The device may be, for example, a host computer.

[0215] The present application also provides a computer-readable storage medium for storing a computer program, which, when executed by a computing device, enables the computing device to implement the content executed by the control module 230 in the method 300 described in at least some of the above embodiments.

[0216] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0217] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the above-described method embodiments and will not be repeated here.

[0218] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0219] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solutions of the embodiments of the present application.

Claims

1. A method for triggering battery thermal runaway, characterized in that: The method comprises: Charging a target battery cell in a battery so that the power of the target battery cell is greater than the power of other battery cells in the battery; When the power of the target battery cell is greater than the power of the other battery cells, the battery is charged to trigger thermal runaway of the battery.

2. The method according to claim 1, characterized in that: Before charging the target battery cell in the battery, the method further includes: The power level of the battery is adjusted to a preset power level, wherein the preset power level is less than the power level of the battery when it is fully charged.

3. The method according to claim 2, characterized in that The preset power level is less than or equal to 85% of the power level in a fully charged state.

4. The method according to claim 3, characterized in that The preset power level is 50%, 60%, 70% or 80% of the power level in a fully charged state.

5. The method according to any one of claims 2 to 4, characterized in that Before adjusting the power of the battery to a preset power, the method further includes: Charging the battery to a fully charged state; Wherein, adjusting the power of the battery to a preset power includes: The power of the battery is discharged from the power in the fully charged state to the preset power.

6. The method according to any one of claims 1 to 5, characterized in that The charging of a target battery cell in a battery so that the power of the target battery cell is greater than the power of other battery cells in the battery includes: The target battery cell is charged so that the power of the target battery cell exceeds the power of the other battery cells by more than or equal to 15% of the power in a fully charged state and is less than or equal to 70% of the power in a fully charged state.

7. The method according to claim 6, characterized in that The target battery cell has a power level that exceeds the power levels of the other battery cells by 20%, 30%, 40% or 50% of the power level in a fully charged state.

8. The method according to any one of claims 1 to 7, characterized in that Before charging the target battery cell in the battery, the method further includes: Shield the balancing function of the battery management system of the battery.

9. The method according to any one of claims 1 to 8, characterized in that Before charging the battery, the method further includes: Shielding the overvoltage protection function of the battery management system of the battery.

10. The method according to any one of claims 1 to 9, characterized in that The method further comprises: When at least one of the following conditions is met, charging of the battery is stopped: The battery meets thermal runaway conditions; The temperature of the battery reaches a temperature threshold; The charging time of the battery reaches a time threshold; The voltage of the battery reaches a voltage threshold.

11. The method according to claim 10, characterized in that The thermal runaway conditions include: The voltage of the battery is greater than or equal to 1V and the temperature rise rate of the battery sampled three times in succession is greater than or equal to 3°C / s or the battery status information includes fire or explosion; or, The voltage drop of the battery exceeds 25% of the initial voltage or the temperature of the battery exceeds a temperature threshold, and the temperature rise rate of the battery is greater than or equal to 1° C. / s.

12. The method according to claim 10 or 11, characterized in that: The time threshold is greater than or equal to 4 hours; and / or, The temperature threshold is greater than or equal to 300° C.; and / or, The voltage threshold is greater than or equal to 1.1 times or 1.2 times a charge cut-off voltage of the battery.

13. The method according to any one of claims 1 to 12, characterized in that The target battery cell includes one or more battery cells, and the multiple battery cells are connected in parallel and / or in series.

14. The method according to any one of claims 1 to 13, characterized in that The battery is a battery box or a battery cluster.

15. The method according to claim 14, characterized in that The battery is an electrical box, and the target battery cell is located in the middle of the electrical box.

16. The method according to claim 15, characterized in that The battery is a battery cluster, which includes a plurality of electrical boxes. Among the plurality of electrical boxes, the electrical box where the target battery cell is located is located in the middle of the battery cluster, and the target battery cell is located in the middle of the electrical box where the target battery cell is located.

17. The method according to any one of claims 1 to 16, characterized in that The electrical quantity includes any one of a state of charge SOC, a state of energy SOE and a capacity.

18. The method according to any one of claims 1 to 17, characterized in that The charging of the battery comprises: The battery is charged with a constant current or a constant power.

19. The method according to claim 18, characterized in that The constant current charging current is greater than or equal to 1C, or is the maximum allowable current of the battery.

20. The method according to any one of claims 1 to 19, characterized in that The method further comprises: During the charging process of the battery, at least one of the following information of the battery and a monitoring object arranged adjacent to the battery is monitored: Charging time, voltage, temperature, temperature rise rate and status information.

21. The method according to claim 20, characterized in that The status information includes at least one of the following: Locations of expansion, leakage, smoke, fire, explosion, and casing rupture.

22. The method according to any one of claims 1 to 21, characterized in that The target battery cell is accommodated in a box body, the box body includes a first box body part and a second box body part that are interlocked, and the electrode terminal of the target battery cell faces the first box body part. During the charging of the target battery cell, the first box body is removed so that the electrode terminal is electrically connected to the charging and discharging device; The step of charging the target battery cell in the battery includes: The charging and discharging device is controlled to charge the target battery cell.

23. The method according to claim 22, characterized in that The end of the positive lead wire of the charging and discharging device is attached to the positive electrode terminal of the target battery cell, and the end of the negative lead wire of the charging and discharging device is attached to the negative electrode terminal of the target battery cell.

24. The method according to claim 22, characterized in that The end of the positive lead of the charging and discharging device contacts the positive electrode terminal of the target battery cell by pressing the pressing mechanism, and the end of the negative lead of the charging and discharging device contacts the negative electrode terminal of the target battery cell by pressing the pressing mechanism.

25. The method according to any one of claims 1 to 24, characterized in that The method further comprises: The insulation performance of the battery is tested.

26. A system for triggering battery thermal runaway, characterized in that: The system comprises: A battery, the battery comprising a target battery cell; a charging and discharging module; and Control module for: Controlling the charging and discharging module to charge the target battery cell so that the power of the target battery cell is greater than the power of other battery cells in the battery; When the power of the target battery cell is greater than the power of the other battery cells, the charging and discharging module is controlled to charge the battery.

27. The system according to claim 26, characterized in that The charge and discharge module includes a first charge and discharge device and a second charge and discharge device, wherein the first charge and discharge device is used to charge and discharge the target battery cell, and the second charge and discharge device is used to charge and discharge the battery.

28. The system according to claim 27, characterized in that The target battery cell is accommodated in a box body, the box body includes a first box body part and a second box body part that are interlocked, and the electrode terminal of the target battery cell faces the first box body part. Wherein, during the process of the first charging and discharging device charging the target battery cell, the first box body is in a removed state so that the electrode terminal is connected to the first charging and discharging device.

29. The system according to claim 28, characterized in that The end of the positive lead of the first charge and discharge device is attached to the positive electrode terminal of the target battery cell, and the end of the negative lead of the first charge and discharge device is attached to the negative electrode terminal of the target battery cell.

30. The system according to claim 28, characterized in that During the process of the first charging and discharging device charging and discharging the target battery cell, the end of the positive electrode wire of the first charging and discharging device contacts the positive electrode terminal of the target battery cell through the pressing of the pressing mechanism, and the end of the negative electrode wire of the first charging and discharging device contacts the negative electrode terminal of the target battery cell through the pressing of the pressing mechanism.

31. A system according to any one of claims 26 to 30, characterized in that The charging and discharging module is also used for: Before charging the target battery cell in the battery, the power of the battery is adjusted to a preset power, where the preset power is less than the power of the battery in a fully charged state.

32. The system according to claim 31, characterized in that The preset power level is less than or equal to 85% of the power level in a fully charged state.

33. The system according to claim 32, characterized in that The preset power level is 50%, 60%, 70% or 80% of the power level in a fully charged state.

34. A system according to any one of claims 31 to 33, characterized in that The charging and discharging module is specifically used for: Before adjusting the power of the battery to a preset power, charging the battery to a fully charged state; The power of the battery is discharged from the power in the fully charged state to the preset power.

35. A system according to any one of claims 26 to 34, characterised in that The charging and discharging module is specifically used for: The target battery cell is charged so that the power of the target battery cell exceeds the power of the other battery cells by more than or equal to 15% of the power in a fully charged state and is less than or equal to 70% of the power in a fully charged state.

36. The system according to claim 35, characterized in that The target battery cell has a power level that exceeds the power levels of the other battery cells by 20%, 30%, 40% or 50% of the power level in a fully charged state.

37. A system according to any one of claims 26 to 36, characterized in that The control module is also used to: Before charging the target battery cell in the battery, the balancing function of the battery management system of the battery is shielded.

38. A system according to any one of claims 26 to 37, characterized in that The control module is also used to: Before charging the battery, an overvoltage protection function of a battery management system of the battery is shielded.

39. A system according to any one of claims 26 to 38, characterized in that The control module is further configured to control the charge and discharge module to stop charging the battery when at least one of the following conditions is met: The battery meets thermal runaway conditions; The temperature of the battery reaches a temperature threshold; The charging time of the battery reaches a time threshold; The voltage of the battery reaches a voltage threshold.

40. The system according to claim 39, characterized in that The thermal runaway conditions include: The voltage of the battery is greater than or equal to 1V and the temperature rise rate of the battery sampled three times in succession The rate is greater than or equal to 3°C / s, or the battery status information includes fire or explosion; or, The voltage drop of the battery exceeds 25% of the initial voltage or the temperature of the battery exceeds a temperature threshold, and the temperature rise rate of the battery is greater than or equal to 1° C. / s.

41. The system according to claim 39 or 40, characterized in that The time threshold is greater than or equal to 4 hours, and / or the temperature threshold is greater than or equal to 300° C., and / or the voltage threshold is greater than or equal to 1.1 times or 1.2 times the charging cut-off voltage of the battery.

42. A system according to any one of claims 26 to 41, characterised in that The target battery cell includes one or more battery cells, and the multiple battery cells are connected in parallel and / or in series.

43. A system according to any one of claims 26 to 42, characterised in that The battery includes an electric box or a battery cluster.

44. The system according to claim 43, characterized in that The battery is an electrical box, and the target battery cell is located in the middle of the electrical box.

45. The system according to claim 44, characterized in that The battery is a battery cluster, which includes a plurality of electrical boxes. Among the plurality of electrical boxes, the electrical box where the target battery cell is located is located in the middle of the battery cluster, and the target battery cell is located in the middle of the electrical box where the target battery cell is located.

46. ​​A system according to any one of claims 26 to 45, characterised in that The electrical quantity includes any one of a state of charge SOC, a state of energy SOE and a capacity.

47. A system according to any one of claims 26 to 46, characterized in that The charging and discharging module is specifically used for: The battery is charged with a constant current or a constant power.

48. The system according to claim 47, characterized in that The constant current charging current is greater than or equal to 1C, or is the maximum allowable current of the battery.

49. A system according to any one of claims 26 to 48, characterized in that The control module is also used to: In the process of the charging and discharging module charging the battery, at least one of the following information of the battery and a monitoring object arranged adjacent to the battery is monitored: Charging time, voltage, temperature, temperature rise rate and status information.

50. The system according to claim 49, characterized in that The status information includes at least one of the following: Locations of expansion, leakage, smoking, fire, explosion, and casing rupture.

51. A system according to any one of claims 26 to 50, characterized in that The system further comprises an insulation monitoring module, and the control module is further configured to: The insulation monitoring module is controlled to test the insulation performance of the battery.

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