Battery system thermal runaway prevention method, battery system, storage medium and vehicle

Abstract

The invention discloses a battery system thermal runaway prevention method, a battery system, a storage medium and a vehicle. The battery system thermal runaway prevention method comprises the steps that the internal short circuit state of the battery system is acquired; according to the internal short circuit state, the battery system is controlled to execute a thermal runaway prevention strategy, thermal runaway prevention can be carried out on the internal short circuit state of the battery system by adopting the method, so that the heat release rate of the battery is reduced, and the problem of thermal runaway of the battery system is avoided.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method for preventing thermal runaway of a battery system, a battery system, a storage medium and a vehicle. Background Art

[0002] In the related art, a cooling system is used to cool down battery cells with a risk of thermal runaway to reduce the possibility of thermal runaway. However, after the cooling process, the battery system is still in a highly active state, and when the heat release rate of the battery is greater than the cooling rate or the cooling system is turned off, the battery system still has a high risk of thermal runaway. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a method for preventing thermal runaway of a battery system, which can prevent thermal runaway in the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery, thereby avoiding the problem of thermal runaway of the battery system.

[0004] A second objective of the present invention is to provide a battery system.

[0005] A third object of the present invention is to provide a computer storage medium.

[0006] A fourth object of the present invention is to provide a vehicle.

[0007] In order to solve the above problems, a first aspect of an embodiment of the present invention provides a method for preventing thermal runaway of a battery system, comprising: obtaining an internal short circuit state of the battery system; and controlling the battery system to execute a thermal runaway prevention strategy according to the internal short circuit state.

[0008] According to the method for preventing thermal runaway of a battery system in an embodiment of the present invention, thermal runaway prevention strategies corresponding to internal short-circuit states of different battery systems are preset in the battery system. When the internal short-circuit state of the battery system is detected, the battery system is controlled to execute the thermal runaway prevention strategy corresponding to the internal short-circuit state to prevent thermal runaway. Therefore, compared with the method of preventing thermal runaway of the battery system by means of a cooling system, in the present application, corresponding thermal runaway prevention strategies are executed according to different internal short-circuit states of the battery system, that is, thermal runaway prevention is performed for the internal short-circuit state of the battery system, thereby reducing the heat release rate of the battery and avoiding the problem of thermal runaway of the battery system.

[0009] In some embodiments, controlling the battery system to execute a thermal runaway prevention strategy according to the internal short circuit state includes: determining a short circuit protection level according to the internal short circuit state; and controlling the battery system to execute a thermal runaway prevention strategy according to the short circuit protection level.

[0010] In some embodiments, the short-circuit protection level includes a first protection level, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short-circuit protection level, including: determining that the short-circuit protection level is the first protection level; obtaining a safe state threshold for preventing thermal runaway of the battery system; controlling the battery system to cut off external power supply; and controlling the battery system to perform discharge processing until the state parameter of the battery system is lower than the safe state threshold.

[0011] In some embodiments, after determining that the short circuit protection level is the first protection level, the prevention method further includes: controlling the battery system to send a thermal runaway warning signal.

[0012] In some embodiments, the battery system includes multiple battery modules, the short-circuit protection level includes a second protection level, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short-circuit protection level, including: determining that the short-circuit protection level is the second protection level; obtaining a safe state threshold for preventing thermal runaway of the battery system; controlling the battery system to cut off external power supply; and controlling the battery module with a short-circuit fault in the battery system to discharge until the state parameter of the battery system is lower than the safe state threshold.

[0013] In some embodiments, after determining that the short circuit protection level is the second protection level, the prevention method further includes: controlling the battery system to send a battery fault reminder signal.

[0014] In some embodiments, the short circuit protection level includes a third protection level, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short circuit protection level, including: after determining that the short circuit protection level is the third protection level, controlling the battery system to send a battery maintenance reminder signal.

[0015] In some embodiments, the battery system includes a lithium battery, the safety status threshold is a state of charge safety threshold, and obtaining the safety status threshold for preventing thermal runaway of the battery system includes: performing multiple battery performance tests on lithium batteries at different states of charge; obtaining the maximum state of charge value corresponding to each battery performance test when thermal runaway does not occur in the lithium battery; and determining the state of charge safety threshold based on the maximum state of charge value corresponding to each battery performance test.

[0016] In some embodiments, determining the state of charge safety threshold according to the maximum state of charge value corresponding to each battery performance test includes: taking the minimum state of charge value among all the maximum state of charge values ​​as the state of charge safety threshold.

[0017] In some embodiments, the battery system includes a lithium battery, the safety status threshold is an OCV safety threshold, and obtaining the safety status threshold for preventing thermal runaway of the battery system includes: performing multiple battery performance tests on lithium batteries at different states of charge; obtaining the maximum state of charge value corresponding to each battery performance test when thermal runaway does not occur in the lithium battery; obtaining a SOC-OCV relationship model; and determining the OCV safety threshold based on the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model.

[0018] In some embodiments, the OCV safety threshold is determined based on the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model, including: determining the minimum state of charge value among all maximum state of charge values; and determining the OCV safety threshold based on the minimum state of charge value and the SOC-OCV relationship model.

[0019] In some embodiments, the discharge process includes: obtaining a thermal runaway limit resistance value of the battery system; determining a maximum allowable discharge current according to the thermal runaway limit resistance value; and controlling the battery system to perform a discharge process according to the maximum allowable discharge current.

[0020] In some embodiments, the battery system includes a lithium battery, and obtaining the thermal runaway limit resistance value of the battery system includes: controlling the lithium battery to reach a fully charged state; performing a short-circuit performance test on the lithium battery to obtain a minimum short-circuit resistance value of the lithium battery when no thermal runaway occurs; and using the minimum short-circuit resistance value as the thermal runaway limit resistance value.

[0021] In some embodiments, obtaining the internal short circuit state of the battery system includes: obtaining a temperature change and a leakage current value of the battery system; and determining the internal short circuit state according to the temperature change and the leakage current value.

[0022] A second aspect of the present invention provides a battery system, comprising: at least one processor; a memory communicatively connected to at least one of the processors; wherein the memory stores a computer program executable by at least one of the processors, and when at least one of the processors executes the computer program, the method for preventing thermal runaway of the battery system as described in the above embodiment is implemented.

[0023] The battery system according to the embodiment of the present invention can prevent thermal runaway in the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and further avoiding the problem of thermal runaway of the battery system.

[0024] A third aspect of the present invention provides a computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for preventing thermal runaway of a battery system as described in the above embodiment is implemented.

[0025] A fourth aspect of the present invention provides a vehicle, comprising the battery system described in the above embodiment.

[0026] According to the vehicle of the embodiment of the present invention, thermal runaway prevention can be performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and further avoiding the problem of thermal runaway of the battery system.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a flow chart of a method for preventing thermal runaway of a battery system according to an embodiment of the present invention; Figure 2 is a flow chart of a method for preventing thermal runaway of a battery system according to another embodiment of the present invention; Figure 3 is a structural block diagram of a battery system according to an embodiment of the present invention; Figure 4 is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0029] Reference numerals: Battery system 10; Vehicle 20; Processor 1; Memory 2. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0031] As one of the most important energy storage systems, lithium-ion batteries have been widely used in portable electronic devices, fixed energy storage, electric vehicles and other fields due to their unique advantages such as high energy / power density, long cycle life, no memory effect, and reduced local air pollution. However, electrode materials with higher energy density show lower thermal stability, which may increase the safety risks of lithium-ion battery systems in tight spaces. Although manufacturers have adopted new technologies such as internal material improvements and external system control to reduce the occurrence of failures, the use of lithium-ion batteries still poses safety risks.

[0032] In order to solve the above problems, an embodiment of the first aspect of the present invention provides a method for preventing thermal runaway of a battery system. This method can be used to prevent thermal runaway in an internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and avoiding the problem of thermal runaway of the battery system.

[0033] Reference below Figure 1 A method for preventing thermal runaway of a battery system according to an embodiment of the present invention is described. As shown in the figure, the method at least includes: step S1 to step S2.

[0034] Step S1, obtaining the internal short circuit state of the battery system.

[0035] Specifically, due to mechanical abuse, electrical abuse and thermal abuse of the battery system, an internal short circuit occurs in the battery system, where mechanical abuse includes impact, puncture, extrusion and falling, and electrical abuse includes overcharging, overdischarging or short circuiting, and thermal abuse includes low temperature use, high temperature use and heating the battery, etc., to obtain the internal short circuit state of the battery system, where the internal short circuit state can be the initial stage of short circuit, the middle stage of short circuit and the final stage of short circuit. In addition, the battery system can be a lithium-ion battery system.

[0036] In an embodiment, the internal short circuit state of the battery system may be detected by the temperature, gas, and voltage, current, and capacity based on electrical characteristics of the battery, without limitation.

[0037] Step S2, controlling the battery system to execute a thermal runaway prevention strategy according to the internal short circuit state.

[0038] Specifically, in the related art, the battery cells with thermal runaway risk are cooled by a cooling system to reduce the possibility of thermal runaway. However, after the cooling process, the battery system is still in a highly active state, and when the heat release rate of the battery is greater than the cooling rate or the cooling system is turned off, the battery system still has a greater risk of thermal runaway. In order to solve this problem, in the present application, one or more thermal runaway prevention strategies are preset in the battery system according to the internal short circuit state of the battery system. For example, corresponding thermal runaway prevention strategies are preset according to the initial short circuit, the middle short circuit and the final short circuit. When the internal short circuit state of the battery system is detected, the battery system generates a large amount of Joule heat and chemical reaction heat at this time, and the battery system is controlled to execute the thermal runaway prevention strategy according to the internal short circuit state. For example, the corresponding thermal runaway prevention strategy at the end of the short circuit is to control the discharge of the battery system, so as to timely block the occurrence of thermal runaway before the battery is about to have thermal runaway. Therefore, in the present application, the battery system is controlled to execute the thermal runaway prevention strategy through the internal short circuit state, that is, thermal runaway prevention is performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and avoiding the problem of thermal runaway of the battery system. In addition, the prevention method in this application can be used as a safety status protection and emergency treatment measure for lithium-ion battery products such as consumer products, power battery products and energy storage products.

[0039] According to the method for preventing thermal runaway of a battery system in an embodiment of the present invention, thermal runaway prevention strategies corresponding to internal short-circuit states of different battery systems are preset in the battery system. When the internal short-circuit state of the battery system is detected, the battery system is controlled to execute the thermal runaway prevention strategy corresponding to the internal short-circuit state to prevent thermal runaway. Therefore, compared with the method of preventing thermal runaway of the battery system by means of a cooling system, in the present application, corresponding thermal runaway prevention strategies are executed according to different internal short-circuit states of the battery system, that is, thermal runaway prevention is performed for the internal short-circuit state of the battery system, thereby reducing the heat release rate of the battery and avoiding the problem of thermal runaway of the battery system.

[0040] In some embodiments, controlling the battery system to execute a thermal runaway prevention strategy according to an internal short circuit state includes: determining a short circuit protection level according to the internal short circuit state; and controlling the battery system to execute a thermal runaway prevention strategy according to the short circuit protection level.

[0041] Specifically, since the severity of the internal short circuit state of the battery system is different, wherein the internal short circuit state can be the initial stage of short circuit, the middle stage of short circuit and the final stage of short circuit, and the short circuit severity of the battery system at the initial stage of short circuit is lower than the short circuit severity at the final stage of short circuit, thermal runaway prevention strategies with different short circuit protection levels are preset according to the internal short circuit states of different severity. Based on this, the short circuit protection level is determined according to the internal short circuit state, and then the battery system is controlled to execute the thermal runaway prevention strategy according to the short circuit protection level. Therefore, in the present application, different emergency responses are made for the internal short circuit states of different severity, that is, thermal runaway prevention is performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and avoiding the problem of thermal runaway of the battery system.

[0042] In addition, the internal short circuit situation is divided into three stages according to whether it causes battery temperature changes or the size of the leakage current, namely, the initial short circuit, the middle short circuit and the final short circuit. In the initial short circuit, the leakage current is small and the battery cell basically does not change temperature. In the middle short circuit, the battery self-discharges significantly and the battery temperature rises significantly but is lower than the melting temperature of the diaphragm. At the final short circuit, the battery temperature rises above the diaphragm dissolution temperature and the cell burns or explodes.

[0043] In some embodiments, the short circuit protection level includes a first protection level, wherein the first protection level may be a short circuit protection level corresponding to an internal short circuit state with a higher degree of severity, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short circuit protection level, including: determining that the short circuit protection level is the first protection level; obtaining a safe state threshold for preventing thermal runaway of the battery system; controlling the battery system to cut off external power supply; and controlling the battery system to perform discharge processing until the state parameters of the battery system are lower than the safe state threshold.

[0044] Among them, the state parameters can be understood as parameters that change during the operation of the battery, such as the state parameters of the battery capacity, current, temperature and voltage.

[0045] Specifically, the larger the battery capacity is, the more electrical energy is released or absorbed per unit time, thereby inducing a stronger chemical reaction and energy conversion, that is, generating more energy, so that the risk of thermal runaway of the battery increases, and the voltage of the battery fluctuates within a certain range under normal conditions. When the voltage of the battery suddenly drops or exceeds the safe range, the battery will experience thermal runaway, and according to the characteristics of thermal runaway of the battery system, the negative electrode LixC6 of the battery reacts violently with the combustion-supporting gas to cause combustion and explosion, and the lower the Li (lithium) content of the negative electrode of the battery, the more stable and safe the battery is. Therefore, when there is a risk of thermal runaway in the battery system, in this application, the external power supply is cut off by controlling the battery system, and the battery system is controlled to perform a discharge process until the state parameter of the battery system is lower than the safety state threshold, thereby avoiding thermal runaway of the battery system in the internal short circuit state. Therefore, in this application, different emergency responses are made for internal short circuit states of different severities, that is, thermal runaway prevention is performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery, avoiding the problem of thermal runaway of the battery system, and preventing the occurrence of heat spread, thereby improving the safety of the battery system and reducing the loss caused by thermal runaway.

[0046] Exemplarily, if the internal short circuit state of the battery system is in the terminal stage of short circuit, the short circuit protection level is determined to be the first protection level, and a safe state threshold for preventing thermal runaway of the battery system is obtained, wherein the safe state threshold may be a safe voltage and a safe battery capacity, and the battery system is controlled to cut off external power supply, that is, the external power supply no longer charges the battery system, and generates heat by charging the battery system to avoid the temperature, voltage and battery capacity of the battery system being higher than the safe state threshold, and all batteries in the battery system are controlled to perform emergency discharge processing so that the state parameters of the battery system are reduced until the state parameters of the battery system are lower than the safe state threshold, that is, the state parameters of the battery system meet the safe state threshold, thereby avoiding thermal runaway of the battery system in the internal short circuit state, and if the state parameters of the battery system are higher than the safe state threshold, the battery system continues to be controlled to perform discharge processing.

[0047] In some embodiments, after determining that the short-circuit protection level is the first protection level, that is, the internal short-circuit state of the battery system is in the terminal stage of short circuit, the battery system is controlled to send a thermal runaway warning signal, that is, the thermal runaway warning signal is displayed in the form of text or language to remind the user that the battery system is about to experience thermal runaway and remind him to stay away from there.

[0048] In some embodiments, the short-circuit protection level is determined to be a second protection level, where the second protection level can be a short-circuit protection level corresponding to an internal short-circuit state with moderate severity; a safe state threshold for preventing thermal runaway of the battery system is obtained; the battery system is controlled to cut off external power supply; and a battery module with a short-circuit fault in the battery system is controlled to discharge until the state parameter of the battery system is lower than the safe state threshold.

[0049] Specifically, if it is determined that the internal short circuit state of the battery system has not reached the end of the short circuit, and it is determined that the internal short circuit state of the battery system is in the middle of the short circuit, the short circuit protection level is determined to be the second protection level, the safety state threshold for preventing thermal runaway of the battery system is obtained, and the battery system is controlled to cut off the external power supply, that is, the external power supply no longer charges the battery system, and generates heat by charging the battery system to avoid the temperature, voltage and battery capacity of the battery system from continuing to rise, and the battery module where the battery with a short circuit fault is located in the battery system is controlled to discharge, or the battery with a short circuit fault in the battery system is controlled to perform emergency discharge, so that the state parameter of the battery system is reduced until the state parameter of the battery system is lower than the safety state threshold, that is, the state parameter of the battery system meets the safety state threshold, thereby avoiding thermal runaway of the battery system in the internal short circuit state, if the state parameter of the battery system is higher than the safety state threshold, then continue to control the battery system to discharge. Therefore, in this application, different emergency responses are made for internal short circuit states of different severity, that is, thermal runaway prevention is performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery, avoiding the problem of thermal runaway of the battery system, improving the safety of the battery system and reducing the loss caused by thermal runaway.

[0050] In some embodiments, after determining that the short circuit protection level is the second protection level, the battery system is controlled to send a battery fault reminder signal, that is, the battery fault reminder signal is displayed in the form of text or language to remind the user that the battery has a fault, so that the user can take corresponding measures.

[0051] In some embodiments, the short circuit protection level includes a third protection level, wherein the third protection level may be a short circuit protection level corresponding to an internal short circuit state of a lower severity, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short circuit protection level. That is, if it is determined that the internal short circuit state of the battery system has not reached the mid-stage of the short circuit, and is determined to be in the early stage of the short circuit, then after determining that the short circuit protection level is the third protection level, it can be determined that the battery system has no safety risks and the battery system can continue to be used, and the battery system is controlled to send a battery maintenance reminder signal to avoid the deterioration of the short circuit situation in the battery system.

[0052] In an embodiment, if it is determined that the battery safety state has not reached the initial stage of short circuit, it is considered that the battery is in a healthy state and can be used normally, and no special treatment of the battery is required.

[0053] In some embodiments, the battery system includes a lithium battery, the safety state threshold is a charge state safety threshold, and obtaining the safety state threshold for preventing thermal runaway of the battery system includes: performing multiple battery performance tests on lithium batteries at different charge states; obtaining the maximum charge state value corresponding to each battery performance test when the lithium battery does not have thermal runaway; and determining the charge state safety threshold based on the maximum charge state value corresponding to each battery performance test.

[0054] Specifically, when the battery system has thermal runaway, the battery system is discharged to control the battery system to stop the discharge process. The lower the state of charge safety threshold and OCV (Open Circuit Voltage) safety threshold, the safer the battery. However, too low a voltage may cause the vehicle to be instantly unusable, thereby affecting the user experience. Therefore, in this application, the state of charge safety threshold is determined by performing multiple battery performance tests on lithium batteries at different states of charge. For example, multiple battery performance tests such as puncture tests, impact tests, and furnace temperature tests are performed on lithium batteries at different states of charge, and the battery performance test method and conditions are not fixed. The battery performance test method or conditions can be adjusted according to the battery usage conditions, such as performing different temperature puncture tests and impact tests on lithium batteries at different states of charge; and performing different speed tests on lithium batteries at different states of charge. The test involves a steel needle puncture test with different rates and sizes; and a furnace temperature test with different heating rates and maximum temperatures on lithium batteries at different states of charge. Thus, multiple battery performance tests are performed on lithium batteries at different states of charge to obtain the maximum state of charge value, i.e., the battery capacity, corresponding to each battery performance test when no thermal runaway occurs in the lithium battery. The state of charge safety threshold is then determined based on the maximum state of charge value corresponding to each battery performance test. Thus, the state of charge safety threshold is obtained. When there is a risk of thermal runaway in the battery system, the battery system can be quickly discharged to the OCV safety threshold, which can not only ensure the safety of the vehicle, but also provide users with sufficient time for emergency processing, thereby improving the user experience.

[0055] In some embodiments, a state of charge safety threshold is determined based on the maximum state of charge value corresponding to each battery performance test, including using the minimum state of charge value among all maximum state of charge values ​​as the state of charge safety threshold, that is, the minimum state of charge value is used as the safety threshold for the battery system to prevent thermal runaway, thereby controlling the execution of the thermal runaway prevention strategy through the state of charge safety threshold, thereby avoiding thermal runaway of the battery system under an internal short circuit state.

[0056] In some embodiments, the battery system includes a lithium battery, the safety state threshold is an OCV safety threshold, and the safety state threshold for preventing thermal runaway of the battery system is obtained. That is, when the battery system has thermal runaway, the battery system is discharged to control the battery system to stop discharging. The lower the state of charge safety threshold and the OCV safety threshold, the safer the battery. However, too low a voltage may cause the vehicle to be instantly unusable, thereby affecting the user experience. Therefore, in this application, the OCV safety threshold is determined by performing multiple battery performance tests on lithium batteries at different states of charge. For example, multiple battery performance tests such as acupuncture tests, impact tests, and furnace temperature tests are performed on lithium batteries at different states of charge, and the maximum state of charge value corresponding to each battery performance test when thermal runaway does not occur in the lithium battery is obtained, and then the SOC (State The SOC-OCV relationship model is used to obtain the fitting relationship curve between SOC and OVC, wherein SOC and OVC are in a one-to-one correspondence, and then the OCV safety threshold is determined according to the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model, that is, the SOC-OCV relationship model is queried through the maximum state of charge value corresponding to each battery performance test to obtain the corresponding OCV safety threshold, so that when the battery system has a risk of thermal runaway, the battery system can be quickly discharged to the OCV safety threshold, which can not only ensure the safety of the vehicle, but also provide users with sufficient time for emergency processing, thereby improving the user experience.

[0057] In addition, the battery performance test conditions are not fixed and can be adjusted according to the battery usage conditions, such as conducting needle penetration tests and impact tests at different temperatures; conducting needle penetration tests with steel needles of different rates and sizes; and conducting furnace temperature tests with different heating rates and maximum temperatures.

[0058] In some embodiments, the OCV safety threshold is determined based on the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model, including: determining the minimum state of charge value among all maximum state of charge values, and determining the OCV safety threshold based on the minimum state of charge value and the SOC-OCV relationship model, that is, obtaining the OCV safety threshold by querying the SOC-OCV relationship model through the minimum state of charge value, so that when there is a risk of thermal runaway in the battery system, the battery system can be quickly discharged to the OCV safety threshold, which can not only ensure the safety of the vehicle, but also provide users with sufficient time for emergency processing, thereby improving user experience.

[0059] In the embodiments, the OCV safety threshold and state of charge safety threshold mentioned in the present application serve not only as emergency discharge cut-off state and emergency treatment of battery safety protection measures when the battery system has thermal runaway, but also as a safe charge state when the battery cell is disassembled and repaired after the battery system has risks, and also as a safe charge state when the electronic equipment is disassembled and repaired.

[0060] In some embodiments, when the battery system is at risk of thermal runaway, emergency discharge processing is required for the battery system, and the sooner the state parameters of the battery system reach the OCV safety threshold and the state of charge safety threshold, the better. However, excessive discharge current may increase the risk of thermal runaway of the battery system. In order to solve this problem, the present application controls the discharge of the battery system by obtaining the maximum allowable discharge current. That is to say, the thermal runaway limit resistance value of the battery system is obtained, and the maximum allowable discharge current is determined according to the thermal runaway limit resistance value. Then, the battery system is controlled to perform discharge processing according to the maximum allowable discharge current. Thus, the battery system is controlled to discharge by obtaining the maximum allowable discharge current, thereby quickly reducing the state parameters of the battery system and avoiding the problem of thermal runaway of the battery system caused by excessive discharge current.

[0061] In some embodiments, the battery system includes a lithium battery, and the thermal runaway limit resistance value of the battery system is obtained, that is, the lithium battery is controlled to reach a fully charged state, and a short-circuit performance test is performed on the fully charged lithium battery, that is, the short-circuit resistance is changed to obtain the minimum short-circuit resistance value of the lithium battery when thermal runaway does not occur; the minimum short-circuit resistance value is used as the thermal runaway limit resistance value, and the maximum allowable discharge current of the lithium battery when thermal runaway does not occur is calculated by the maximum discharge voltage and the thermal runaway limit resistance value.

[0062] In addition, in the process of obtaining the minimum short-circuit resistance value, short-circuit tests can be performed on the lithium-ion battery at different temperatures according to the application conditions to obtain a thermal runaway limit resistance value with more practical application value, thereby preventing the problem of thermal runaway of the battery caused by the discharge process due to the battery temperature in the actual process.

[0063] In some embodiments, obtaining the internal short circuit state of the battery system includes: obtaining a temperature change and a leakage current value of the battery system; and determining the internal short circuit state according to the temperature change and the leakage current value.

[0064] Specifically, since the temperature changes greatly when thermal runaway occurs in the battery system, the internal short circuit state of the battery system can be determined based on the temperature change and leakage current of the battery system. For example, if the temperature change is greater than the preset change based on the occurrence of thermal runaway in the battery system, the battery system is determined to be in an internal short circuit state, and since the temperature of the battery system basically does not change and the leakage current is small in the early stage of the short circuit, and the temperature of the battery system changes significantly but is lower than the melting temperature of the diaphragm in the middle stage of the short circuit, and the battery temperature rises above the dissolution temperature of the diaphragm at the end of the short circuit, the internal short circuit state of the battery system can be determined by the temperature change.

[0065] Reference below Figure 3 The method for preventing thermal runaway of a battery system according to an embodiment of the present invention is described by way of example, and the specific contents are as follows.

[0066] Step S3, inputting the internal short circuit state of the battery system.

[0067] Step S4, determining whether the internal short circuit state is at the end of the short circuit, if yes, proceed to step S5 and step S7, otherwise proceed to step S6.

[0068] Step S5, reminding the user that the battery system is about to thermally run away.

[0069] Step S6, determining whether the internal short circuit state is in the middle stage of the short circuit, if yes, executing steps S7 and S10, otherwise executing step S11.

[0070] Step S7: the battery system cuts off external power supply and performs a discharge process.

[0071] Step S8, determining whether the state parameters of the battery system meet the OCV safety threshold and the state of charge safety threshold, if yes, proceed to step S9, otherwise proceed to step S7.

[0072] Step S9, the battery system can be disassembled and repaired.

[0073] Step S10: The battery is damaged, and the battery needs to be replaced.

[0074] Step S11, determining whether the internal short circuit state is in the initial stage of the short circuit, if yes, proceed to step S12, otherwise, proceed to step S13.

[0075] Step S12, repairing the battery system under the OCV safety threshold state of charge safety threshold.

[0076] Step S13: the battery system is not in an internal short circuit state, that is, the battery system is healthy.

[0077] A second aspect of the present invention provides a battery system, such as Figure 3 As shown, the battery system 10 includes: at least one processor 1 and a memory 2 communicatively connected to the at least one processor 1 .

[0078] The memory stores a computer program that can be executed by at least one processor, and when at least one processor executes the computer program, the method for preventing thermal runaway of the battery system in the above embodiment is implemented.

[0079] It should be noted that the specific implementation method of the battery system in the embodiment of the present invention is similar to the specific implementation method of the method for preventing thermal runaway of the battery system in any of the above-mentioned embodiments of the present invention. Please refer to the description of the method part for details. In order to reduce redundancy, it will not be repeated here.

[0080] The battery system according to the embodiment of the present invention can prevent thermal runaway in the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and further avoiding the problem of thermal runaway of the battery system.

[0081] A third aspect of the present invention provides a computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for preventing thermal runaway of a battery system of the above embodiment is implemented.

[0082] A fourth aspect of the present invention provides a vehicle 20, such as Figure 4 As shown, the vehicle 20 includes the battery system 10 of the above embodiment.

[0083] It should be noted that the specific implementation method of the vehicle of the embodiment of the present invention is similar to the specific implementation method of the method for preventing thermal runaway of the battery system of any of the above-mentioned embodiments of the present invention. Please refer to the description of the method part for details. In order to reduce redundancy, it will not be repeated here.

[0084] According to the vehicle of the embodiment of the present invention, thermal runaway prevention can be performed for the internal short circuit state of the battery system, thereby reducing the heat release rate of the battery and further avoiding the problem of thermal runaway of the battery system.

[0085] In the description of this specification, any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code including one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0086] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0087] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0088] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0089] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0090] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0092] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preventing thermal runaway of a battery system, characterized in that: include: Acquiring an internal short circuit state of the battery system; The battery system is controlled to execute a thermal runaway prevention strategy according to the internal short circuit state.

2. The method for preventing thermal runaway of a battery system according to claim 1, characterized in that: Controlling the battery system to execute a thermal runaway prevention strategy according to the internal short circuit state includes: Determining a short circuit protection level according to the internal short circuit state; The battery system is controlled to execute a thermal runaway prevention strategy according to the short circuit protection level.

3. The method for preventing thermal runaway of a battery system according to claim 2, characterized in that: The short circuit protection level includes a first protection level, and controlling the battery system to execute a thermal runaway prevention strategy according to the short circuit protection level includes: Determining the short circuit protection level to be the first protection level; Obtaining a safety state threshold for preventing thermal runaway of the battery system; Controlling the battery system to cut off external power supply; The battery system is controlled to perform a discharge process until a state parameter of the battery system is lower than the safety state threshold.

4. The method for preventing thermal runaway of a battery system according to claim 3, characterized in that: After determining that the short circuit protection level is the first protection level, the prevention method further includes: controlling the battery system to send a thermal runaway warning signal.

5. The method for preventing thermal runaway of a battery system according to claim 2, characterized in that: The battery system includes a plurality of battery modules, the short circuit protection level includes a second protection level, and the battery system is controlled to execute a thermal runaway prevention strategy according to the short circuit protection level, including: Determining the short circuit protection level to be the second protection level; Obtaining a safety state threshold for preventing thermal runaway of the battery system; Controlling the battery system to cut off external power supply; The battery module with a short circuit fault in the battery system is controlled to perform a discharge process until the state parameter of the battery system is lower than the safety state threshold.

6. The method for preventing thermal runaway of a battery system according to claim 5, characterized in that: After determining that the short circuit protection level is the second protection level, the prevention method further includes: controlling the battery system to send a battery fault reminder signal.

7. The method for preventing thermal runaway of a battery system according to claim 2, characterized in that: The short circuit protection level includes a third protection level, and controlling the battery system to execute a thermal runaway prevention strategy according to the short circuit protection level includes: After determining that the short circuit protection level is the third protection level, controlling the battery system to send a battery maintenance reminder signal.

8. The method for preventing thermal runaway of a battery system according to claim 3 or 5, characterized in that: The battery system includes a lithium battery, the safety state threshold is a charge state safety threshold, and obtaining the safety state threshold for preventing thermal runaway of the battery system includes: Conduct multiple battery performance tests on lithium batteries at different states of charge; Obtaining a maximum state of charge value corresponding to each battery performance test when the lithium battery does not experience thermal runaway; The state of charge safety threshold is determined according to the maximum state of charge value corresponding to each battery performance test.

9. The method for preventing thermal runaway of a battery system according to claim 8, characterized in that: Determining the state of charge safety threshold according to the maximum state of charge value corresponding to each battery performance test includes: The minimum state of charge value among all maximum state of charge values ​​is used as the state of charge safety threshold.

10. The method for preventing thermal runaway of a battery system according to claim 3 or 5, characterized in that: The battery system includes a lithium battery, the safety state threshold is an OCV safety threshold, and obtaining the safety state threshold for preventing thermal runaway of the battery system includes: Conduct multiple battery performance tests on lithium batteries at different states of charge; Obtaining a maximum state of charge value corresponding to each battery performance test when the lithium battery does not experience thermal runaway; Obtain the SOC-OCV relationship model; The OCV safety threshold is determined according to the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model.

11. The method for preventing thermal runaway of a battery system according to claim 10, characterized in that: Determining the OCV safety threshold according to the maximum state of charge value corresponding to each battery performance test and the SOC-OCV relationship model includes: determining a minimum state of charge value among all maximum state of charge values; The OCV safety threshold is determined according to the minimum state of charge value and the SOC-OCV relationship model.

12. The method for preventing thermal runaway of a battery system according to claim 3 or 5, characterized in that: The discharge treatment comprises: Obtaining a thermal runaway limit resistance value of the battery system; Determining a maximum allowable discharge current according to the thermal runaway limit resistance value; The battery system is controlled to perform a discharge process according to the maximum allowable discharge current.

13. The method for preventing thermal runaway of a battery system according to claim 12, characterized in that: The battery system includes a lithium battery, and obtaining a thermal runaway limit resistance value of the battery system includes: Controlling the lithium battery to reach a fully charged state; Performing a short-circuit performance test on the lithium battery to obtain a minimum short-circuit resistance value of the lithium battery when thermal runaway does not occur; The minimum short-circuit resistance value is used as the thermal runaway limit resistance value.

14. The method for preventing thermal runaway of a battery system according to claim 1, characterized in that: Obtaining the internal short circuit state of the battery system includes: Obtaining a temperature change and a leakage current value of the battery system; The internal short circuit state is determined according to the temperature change amount and the leakage current value.

15. A battery system, characterized in that: include: at least one processor; a memory communicatively coupled to at least one of the processors; Wherein, the memory stores a computer program that can be executed by at least one of the processors, and when at least one of the processors executes the computer program, the method for preventing thermal runaway of the battery system according to any one of claims 1 to 14 is implemented.

16. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for preventing thermal runaway of a battery system according to any one of claims 1 to 14 is implemented.

17. A vehicle, characterized in that: A battery system comprising the battery system of claim 15.

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