A battery thermal runaway swelling force feature identification and early warning method, system and device

Abstract

The application relates to the technical field of batteries, and discloses a battery thermal runaway expansion force feature identification and early warning method, system and device, which comprises the following steps: presetting a threshold value and an initial expansion force value according to the change characteristics of the expansion force of a battery during charging and discharging under different current multiples; charging and discharging or static placing a to-be-tested battery under a preset current multiple, and obtaining a current expansion force value of the to-be-tested battery; judging the size relationship between the current expansion force value of the to-be-tested battery and the threshold value, if the current expansion force value is greater than or equal to the threshold value, first-level early warning is carried out and the next step is entered; otherwise, the previous step is entered; calculating each expansion force peak value and the time corresponding to each expansion force peak value according to the current expansion force value and the initial expansion force value of the to-be-tested battery; presetting different early warning levels, and judging the early warning level corresponding to the to-be-tested battery; and carrying out different early warnings according to the early warning level. The application can give an alarm signal as early as possible before obvious thermal runaway of the battery occurs, and can early warn the harmfulness degree of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery thermal runaway swelling force feature identification and early warning method, system and device. BACKGROUND

[0002] Due to the influence of environmental pollution, energy shortage, greenhouse effect and the like, in recent years, the new energy automobile industry has developed rapidly in the whole world. However, the new energy automobile fire accidents also show a trend of continuous increase, which has become one of the biggest obstacles to the commercialization of electric vehicles.

[0003] To solve the safety problem of lithium ion battery, it is necessary to optimize from different dimensions such as battery key material design, cell design, cell manufacturing process control, battery system integration, safety test verification and safety warning. Since the lithium ion battery is an extremely complex electrochemical system, during normal charging and discharging and thermal runaway process, different processes such as electricity, heat, chemistry, mechanics and gas dynamics will interact with each other.

[0004] For thermal runaway early warning, the commonly used methods at present mainly judge based on voltage, temperature, internal resistance, released gas and smoke. For these methods, when the battery reaches the set condition, obvious thermal runaway has occurred, so the battery state cannot be responded in time; when thermal runaway occurs, the swelling force as the quantity of the temperature change and chemical reaction in the battery, the swelling force signal appears earlier than the traditional early warning signals such as voltage and temperature, and will produce complex characteristics with the development progress of thermal runaway, so the thermal runaway state can be judged according to the change of swelling force. However, in order to apply the swelling force signal in the electric vehicle power battery management system, it is necessary to further develop the related feature grabbing method, and based on the grabbed features, the thermal runaway is graded and warned. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a battery thermal runaway swelling force feature identification and early warning method, system and device, which gives an alarm signal as early as possible before the battery occurs obvious thermal runaway, and warns the degree of harm of the battery, provides sufficient time for the active heat dissipation, active gas release of the battery system level and personnel escape, and improves the application safety level of electric vehicles.

[0006] In the first aspect, the present application provides a battery thermal runaway swelling force feature identification and early warning method, comprising the following steps:

[0007] S1, presetting threshold value and initial swelling force value according to the change characteristics of the swelling force of the battery under different current rate during charging and discharging process;

[0008] S2, performing charging and discharging or static state on the battery under test at a preset current rate, and obtaining a current swelling force value of the battery under test;

[0009] S3, judging the size relationship between the current swelling force value of the battery under test and the threshold value, if the current swelling force value is greater than or equal to the threshold value, performing a first level warning and entering S4; otherwise, entering S2;

[0010] S4, according to the current swelling force value and the initial swelling force value of the battery under test, calculating each swelling force peak value and the time corresponding to each swelling force peak value by using a peak finding algorithm; the swelling force peak value includes a first swelling force peak value, a second swelling force peak value and a third swelling force peak value;

[0011] S5, presetting different warning levels, and judging the corresponding warning level of the battery under test according to each swelling force peak value and the time corresponding to each swelling force peak value.

[0012] Further, the calculation of each swelling force peak value by using the peak finding algorithm includes:

[0013] S41, obtaining the swelling force values of the previous k seconds and the next k seconds of the current swelling force value; k is a constant not equal to 0;

[0014] S42, judging the size relationship between the current swelling force value and the swelling force values of the previous k seconds and the next k seconds, if the current swelling force value is greater than or equal to the swelling force value of the previous k seconds and greater than or equal to the swelling force value of the next k seconds, the current swelling force value is a swelling force peak value; otherwise, the current swelling force value is not a swelling force peak value;

[0015] S43, if the current swelling force value is less than the initial swelling force value, the process ends; if the current swelling force value is greater than or equal to the initial swelling force value, the process enters S41.

[0016] Further, presetting different warning levels, and judging the corresponding warning level of the battery under test according to each swelling force peak value and the time corresponding to each swelling force peak value, includes:

[0017] presetting a first preset value and a second preset value;

[0018] when the first swelling force peak value is detected, a second level warning is performed;

[0019] when the second swelling force peak value is detected, if the difference between the time corresponding to the first swelling force peak value and the time corresponding to the second swelling force peak value is greater than or equal to the first preset value and less than the second preset value, a third level warning is performed;

[0020] if the difference between the time corresponding to the first swelling force peak value and the time corresponding to the second swelling force peak value is less than the first preset value, a fourth level warning is performed;

[0021] when the third swelling force peak value is detected, a fifth level warning is performed.

[0022] When the third expansion force peak is detected, a level 5 warning is issued.

[0023] Furthermore, obtaining the current expansion force value of the battery to be tested includes:

[0024] The current expansion force value is obtained by setting a pressure sensor on the battery to be tested.

[0025] Furthermore, k is negatively correlated with the real-time SOC of the battery under test.

[0026] In a second aspect, the present invention provides a battery thermal runaway expansion force feature recognition and early warning system, comprising:

[0027] Preset module: preset thresholds and initial expansion force values ​​according to the changing characteristics of the expansion force during the charge and discharge process of the battery at different current rates;

[0028] Calculation module: connected to the preset module, used to charge and discharge the battery under test at a preset current rate or let it stand to obtain the current expansion force value of the battery under test; determine the relationship between the current expansion force value of the battery and the threshold value. If the current expansion force value is greater than or equal to the threshold value, a first-level warning is issued and the warning module is entered; otherwise, the calculation in the calculation module is repeated;

[0029] The early warning module is connected to the calculation module and is used to calculate each expansion force peak value and the corresponding time of each expansion force peak value based on the current expansion force value and initial expansion force value of the battery under test using a peak search algorithm; the expansion force peak values ​​include a first expansion force peak value, a second expansion force peak value, and a third expansion force peak value. Different early warning levels are preset and the early warning level corresponding to the battery under test is determined based on each expansion force peak value and the corresponding time of each expansion force peak value.

[0030] In a third aspect, the present invention provides an electronic device comprising: a processor and a memory; the processor is configured to execute the steps of the method described in the first aspect by calling a program or instruction stored in the memory.

[0031] In a fourth aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a program or instruction, wherein the program or instruction enables a computer to execute the steps of the method described in the first aspect.

[0032] The embodiments of the present invention have the following technical effects:

[0033] The present application is directed to the multiple jet flow fire characteristics existing in the battery thermal runaway process, and further directed to the multiple expansion force peak value characteristics associated with the characteristics, a wave peak finding algorithm of the expansion force peak value is proposed, and the thermal runaway state is graded and warned according to whether the wave peak appears and the time interval, the number of the wave peak, each grade indicates the damage situation of the thermal runaway state, accurately reflects the development situation of the battery, so that the personnel can accurately grasp the state of the battery, reduce the decision errors caused by the judgment errors, reduce the loss, and improve the application safety level of the electric vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0035] Figure 1 is a flow chart of the battery thermal runaway expansion force feature recognition and early warning method provided by the embodiment of the present application;

[0036] Figure 2 is a schematic diagram of the expansion force peak value and the corresponding time identified by the peak value finding algorithm in the thermal runaway process of the 51Ah square hard shell ternary / graphite battery at SOC=110% provided by the embodiment of the present application;

[0037] Figure 3 is a schematic diagram of the expansion force peak value and the corresponding time identified by the peak value finding algorithm in the thermal runaway process of the 51Ah square hard shell ternary / graphite battery at SOC=100% provided by the embodiment of the present application;

[0038] Figure 4 is a schematic diagram of the expansion force peak value and the corresponding time identified by the peak value finding algorithm in the thermal runaway process of the 51Ah square hard shell ternary / graphite battery at SOC=50% provided by the embodiment of the present application;

[0039] Figure 5 is a schematic diagram of the expansion force peak value and the corresponding time identified by the peak value finding algorithm in the thermal runaway process of the 51Ah square hard shell ternary / graphite battery at SOC=25% provided by the embodiment of the present application;

[0040] Figure 6 is a schematic diagram of the expansion force peak value and the corresponding time identified by the peak value finding algorithm in the thermal runaway process of the 51Ah square hard shell ternary / graphite battery at SOC=0% provided by the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0042] Firstly, the following is explained:

[0043] Thermal runaway is an abnormal phenomenon that occurs under certain conditions in a battery, involving a rapid rise in internal temperature, acceleration of chemical reactions, and generation and accumulation of gas. These phenomena interact to form a vicious cycle, leading to battery failure and even explosion.

[0044] During the thermal runaway process, the internal temperature and pressure of the battery rise rapidly, causing thermal expansion of the battery materials and electrolyte, as well as generation and accumulation of gas. These phenomena collectively produce significant expansion force, which can cause the battery pressure relief valve or housing to rupture and release gas suddenly when the expansion force exceeds the bearing capacity of the battery pressure relief valve or housing. The sudden release of gas forms a jet fire, posing a serious threat to the battery and the surrounding environment.

[0045] Example 1

[0046] It has been found through research that when a battery undergoes external heating triggering thermal runaway, gas is generated inside the battery accompanied by positive and negative electrode expansion, which leads to an increase in the battery expansion force. When the battery expansion force is less than the battery pressure relief valve opening pressure, the expansion force continues to increase and there is a threshold value, and the detection of the threshold value is usually earlier than the changes in battery voltage and battery temperature.

[0047] When the internal pressure of the battery is greater than the battery pressure relief valve opening pressure, the pressure relief valve opens, and the first expansion force peak value appears. Thereafter, accompanied by multiple jet fires occurring in the battery, multiple peak values of the expansion force appear. Using the threshold value and the first expansion force peak value for thermal runaway early warning has high advance degree, and using multiple peak values for hazard degree early warning has high accuracy.

[0048] Before the battery thermal runaway, the expansion force will exhibit abnormal characteristics, so the hazard degree of the battery thermal runaway can be judged by monitoring the peak value of the expansion force signal.

[0049] Figure 1 is a flowchart of a battery thermal runaway expansion force feature recognition and early warning method provided by an embodiment of the present application. Referring to Figure 1 , specifically comprising:

[0050] S1, presetting a threshold value and an initial expansion force value according to the change characteristics of the expansion force of the battery during charging and discharging at different current rates.

[0051] The battery is charged and discharged at different current rates to obtain the expansion force change characteristics of the battery; a threshold is set according to the expansion force change characteristics, and when the threshold is exceeded, there is a greater possibility of thermal runaway; for example, the threshold can be 4000N.

[0052] The initial expansion force value is the expansion of the battery in a normal state.

[0053] S2, charging and discharging or standing of the battery to be tested at a preset current rate is performed, and the current expansion force value of the battery to be tested is obtained. The current expansion force value can be obtained by setting a pressure sensor on the battery to be tested.

[0054] It should be noted that the state of the battery, such as SOC, is not specifically limited when the condition of "charging and discharging or standing at a preset current rate" is met, and the expansion force of the actual battery is directly monitored.

[0055] S3, the size relationship between the current expansion force value of the battery to be tested and the threshold is judged, if the current expansion force value is greater than or equal to the threshold, a first level warning is performed and S4 is entered; otherwise, S2 is entered.

[0056] When the real-time expansion force is greater than or equal to the threshold, the battery may appear obvious bulging of the shell, and then cause the battery module connection sheet to deform, and there is a risk of local arc. At this time, the probability of thermal runaway is greater, and a first level warning is performed to remind nearby personnel to evacuate as soon as possible.

[0057] If the expansion force is further increased, the thermal runaway will occur when the expansion force reaches the peak value, and the jet fire will be ejected, so it is necessary to monitor the expansion force peak value.

[0058] S4, according to the current expansion force value and the initial expansion force value of the battery to be tested, the peak value finding algorithm is used to calculate each expansion force peak value and the time corresponding to each expansion force peak value; the expansion force peak value includes the first expansion force peak value, the second expansion force peak value and the third expansion force peak value, which are the first, second and third peak values detected respectively.

[0059] The peak value finding algorithm is realized by the following steps:

[0060] S41, the expansion force values of k seconds before and after the current expansion force value are obtained; k is a constant not equal to 0;

[0061] S42, the size relationship between the current expansion force value and the expansion force values of k seconds before and after is judged, if the current expansion force value is greater than or equal to the expansion force value of k seconds before and greater than or equal to the expansion force value of k seconds after, the current expansion force value is the expansion force peak value; otherwise, the current expansion force value is not the expansion force peak value;

[0062] That is, when the following conditions are met, it is determined that the current swelling force value is not the swelling force peak value:

[0063] i. The current swelling force value is less than the swelling force value of the previous k seconds or less than the swelling force value of the next k seconds;

[0064] ii. The current swelling force value is less than the swelling force value of the previous k seconds and less than the swelling force value of the next k seconds.

[0065] S43, if the current swelling force value is less than the initial swelling force value, then end; if the current swelling force value is greater than or equal to the initial swelling force value, then go to S41.

[0066] The peak value determination process described above determines whether the current swelling force value is the maximum in the window by setting a window, i.e. the time of the previous k seconds and the next k seconds of the real-time swelling value. The size of k depends on the real-time SOC of the battery to be tested. The larger the SOC, the smaller the k, i.e. they are negatively correlated. For example, when 75% < SOC ≤ 110%, set k = 0.5; when 35% < SOC ≤ 75%, set k = 1.5; when 10% < SOC ≤ 35%, set k = 6; when 0% ≤ SOC ≤ 10%, set k = 60. The actual situation can be set, and this application does not make too much repetition.

[0067] When the current swelling force value is less than the initial swelling force value, it indicates that the battery is in a normal state, so the search for the peak value is stopped. When the real-time swelling force again exceeds the threshold value, the peak value finding algorithm is used again to determine the peak value.

[0068] S5, preset different warning levels, and determine the warning level corresponding to the battery to be tested according to each swelling force peak value and the time corresponding to each swelling force peak value.

[0069] Specifically, a first preset value and a second preset value are preset, and the specific values can be set according to actual needs; when the first swelling force peak value is detected, i.e. when the first swelling force peak value appears, a secondary warning is performed; when the peak value appears, it indicates that the battery has thermal runaway. At this time, the battery may open the explosion-proof valve, accompanied by a large amount of aerosol, smoke discharge or violent jet fire; the discharged substances are easy to cause short circuit outside the battery, overheating of adjacent batteries, and failure of high-voltage insulation protection inside the battery system.

[0070] When the second expansion force peak value is detected, i.e., a second expansion force peak value is detected, if the difference between the time corresponding to the first expansion force peak value and the time corresponding to the second expansion force peak value is greater than or equal to a first preset value and less than a second preset value, a third level of warning is performed; for example, the first preset value is 2.5 seconds, and the second preset value is 15 seconds. At this time, since the battery appears secondary aerosol, smoke or jet fire injection, the possibility of thermal diffusion occurring in the battery system is higher, and thus the risk is greater. If the difference between the time corresponding to the first expansion force peak value and the time corresponding to the second expansion force peak value is greater than or equal to the second preset value, no warning is performed.

[0071] If the difference between the time corresponding to the first expansion force peak value and the time corresponding to the second expansion force peak value is less than the first preset value, a fourth level of warning is performed; at this time, the aerosol and particulate matter ejected by the battery need to be discharged from the pressure relief valve of the battery pack, and the smaller the interval time, the more likely secondary jet fire appears in a short time, and the greater the challenge of battery pack pressure relief, cooling and arc avoidance, and thus the higher the risk.

[0072] When the third expansion force peak value is detected, i.e., a third expansion force peak value is detected, a fifth level of warning is performed. At this time, the battery thermal runaway reaction is a continuous long-time process, and multiple jet fires corresponding to multiple peak values will cause multiple extrusions and thermal shocks to adjacent batteries, which are more likely to cause thermal diffusion of adjacent batteries, and at the same time make it more difficult to eliminate the risk of battery thermal runaway through external fire extinguishing measures.

[0073] It should be noted that for the fourth peak value, the fifth peak value, etc., the expansion force degree is not enough, which is similar to the case of the third expansion force peak value, and the warning effect is consistent, so the present application is limited to monitoring of the third expansion force peak value.

[0074] In addition, the present application also includes taking different measures according to different warning levels.

[0075] The measures that can be taken are: battery power-off, controlling the power of the fan and water pump to the highest gear to forcibly cool the battery; wherein, for the air cooling system, the power of the fan is controlled to the highest gear to perform the action of forcibly cooling the battery, and the air convection rate inside the battery system is increased to discharge the generated aerosol, smoke, etc. outside the battery system box to try to avoid the occurrence of thermal runaway; starting the fire extinguishing system to spray fire extinguishing agent on the battery to extinguish the fire and combustion that may exist in the battery system, and alarming and prompting through sound and light, etc.; which can be set according to actual conditions, and the present application will not be described in more detail.

[0076] In summary, the application quantifies the thermal runaway state of the battery by taking the expansion force peak value as the judgment condition, and divides the early warning levels according to the peak value, thereby grading the degree of harm of the thermal runaway of the battery; from the second level to the fifth level, the degree of harm is higher and higher, therefore, the corresponding fire-fighting measures are taken in time to reduce the risk.

[0077] Embodiment 2

[0078] Based on Embodiment 1, the application provides a specific implementation case to illustrate Embodiment 1:

[0079] 1) Conduct a lithium ion battery thermal runaway test. The lithium ion battery is a 51 Ah square hard shell ternary / graphite battery. An external heating method is used to trigger the battery to occur thermal runaway, so as to more truly simulate the thermal runaway scenario of the battery in actual use.

[0080] 2) Test the characteristic parameters of the battery during thermal runaway, including battery temperature, voltage, expansion force, and battery thermal runaway combustion image.

[0081] Among them, the battery temperature includes the temperature of the positive and negative electrode lug and the shell temperature, which is obtained by a temperature sensor; the voltage is the positive and negative terminal voltage of the battery, which is obtained by a voltage sensor; the battery expansion force is the expansion force of the side surface of the square hard shell, which is obtained by a pressure sensor, and the pressure sensor can obtain the expansion force of the whole battery module by arranging one pressure sensor in a single battery module, or obtain the expansion force value of each single battery by arranging on the side surface of the single battery; the battery thermal runaway combustion image is collected by a camera.

[0082] The peak value of the battery expansion force data at different SOC is found, and the found expansion force peaks are respectively Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 .

[0083] When SOC=110%, there are 4 expansion force peaks, the first expansion force peak is the highest, which is 7222.6 N, and the interval between the first expansion force peak and the second expansion force peak is 2.26 s.

[0084] When SOC=100%, there are 4 expansion force peaks, the first expansion force peak is the highest, which is 8222.2 N, and the interval between the first expansion force peak and the second expansion force peak is 1.9 s.

[0085] When SOC=50%, there are 4 expansion force peaks, the first expansion force peak is the highest, which is 7036.4 N, and the interval between the first expansion force peak and the second expansion force peak is 1.8 s.

[0086] When SOC=25%, there are three peaks of expansion force, the first peak of expansion force is 6036.8N, and the interval between the first peak of expansion force and the second peak of expansion force is 11.39s.

[0087] When SOC=0%, there is only one peak of expansion force, which is 4968.6N.

[0088] Meanwhile, before the first peak of expansion force appears, when the expansion force reaches 4000N, the expansion force curve has already shown a sharp change, and then quickly reaches the first peak of expansion force, which proves the feasibility of the threshold value of 4000N set in the embodiment 1.

[0089] Embodiment 3

[0090] Based on the content of the embodiment 1, the application provides a battery thermal runaway expansion force feature identification and early warning system, comprising:

[0091] The preset module: according to the change characteristics of the expansion force of the battery in the charging and discharging process under different current rates, the threshold value and the initial expansion force value are preset;

[0092] The calculation module: connected with the preset module, used for charging and discharging or standing of the battery to be tested under the preset current rate, obtaining the current expansion force value of the battery to be tested; judging the size relationship between the current expansion force value of the battery and the threshold value, if the current expansion force value is greater than or equal to the threshold value, then the first level of early warning is carried out and the early warning module is entered; otherwise, the calculation in the calculation module is repeated;

[0093] The early warning module: connected with the calculation module, used for calculating each expansion force peak value and the time corresponding to each expansion force peak value according to the current expansion force value and the initial expansion force value of the battery to be tested by using the peak value finding algorithm; the expansion force peak value includes the first expansion force peak value, the second expansion force peak value and the third expansion force peak value; different early warning levels are preset, and the corresponding early warning level of the battery to be tested is judged according to each expansion force peak value and the time corresponding to each expansion force peak value.

[0094] Other contents can refer to the embodiment 1, which will not be described in detail here.

[0095] Embodiment 4

[0096] The application provides an electronic device, comprising: a processor and a memory; the processor is used for executing the steps of a battery thermal runaway expansion force feature identification and early warning method as described in the embodiment 1 by calling the program or instruction stored in the memory.

[0097] The processor can be a central processing unit (CPU) or other forms of processing units with data processing capability and / or instruction execution capability, and can control other components in the electronic device to perform the desired functions.

[0098] The memory can include one or more computer program products that can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), and / or a cache, etc. The non-volatile memory, for example, can include read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions can be stored on the computer-readable storage media, and the processor can execute the program instructions to implement the battery thermal runaway swelling force feature identification and early warning method of any embodiment of the application described above and / or other desired functions. Various contents such as initial external parameters, threshold values, etc. can also be stored in the computer-readable storage media.

[0099] In addition to the above method and device, the embodiments of the present application can also be a computer program product, which includes computer program instructions that, when executed by a processor, cause the processor to perform the steps of the battery thermal runaway swelling force feature identification and early warning method provided by any embodiment of the present application.

[0100] The computer program product can be written in any combination of one or more programming languages, including object-oriented programming languages, such as Java, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0101] In addition, the embodiments of the present application can also be a computer-readable storage medium, which stores computer program instructions, and the computer program instructions, when executed by a processor, cause the processor to perform the steps of the battery thermal runaway swelling force feature identification and early warning method provided by any embodiment of the present application.

[0102] The computer readable storage medium can be any combination of one or more computer readable medium(s). The computer readable medium can be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0103] It should be noted that the terms used in the present application are only intended to describe specific embodiments and are not intended to limit the scope of the present application. As shown in the specification of the present application, unless the context clearly indicates otherwise, the terms "one", "a", "an", and / or "the" do not refer to the singular, but can also include the plural. The terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method or device including the element.

[0104] It should also be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise specified and limited, the terms "mount", "connect", "connect" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected internally between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application.

Claims

1. A method for identifying and warning the characteristics of battery thermal runaway expansion force, characterized in that: The steps include: S1. Preset a threshold value and an initial expansion force value according to the change characteristics of the expansion force during the charge and discharge process of the battery at different current rates; S2. Charge and discharge the battery under test at a preset current rate or leave it at rest to obtain the current expansion force value of the battery under test; S3, determining the relationship between the current expansion force value of the battery under test and the threshold value. If the current expansion force value is greater than or equal to the threshold value, a first-level warning is issued and the process proceeds to S4; Otherwise, go to S2; S4. Calculate each expansion force peak value and the time corresponding to each expansion force peak value using a peak value search algorithm based on the current expansion force value and the initial expansion force value of the battery to be tested; The expansion force peak value includes a first expansion force peak value, a second expansion force peak value and a third expansion force peak value; Calculating each expansion force peak value using a peak finding algorithm includes: S41, obtaining the expansion force values ​​k seconds before and k seconds after the current expansion force value; k is a constant not equal to 0; S42: Determine the relationship between the current expansion force value and the expansion force values ​​k seconds before and k seconds after. If the current expansion force value is greater than or equal to the expansion force value k seconds before and greater than or equal to the expansion force value k seconds after, the current expansion force value is the peak expansion force value; otherwise, the current expansion force value is not the peak expansion force value. S43: If the current expansion force value is less than the initial expansion force value, then the process ends; if the current expansion force value is greater than or equal to the initial expansion force value, then the process proceeds to S41; S5. Preset different warning levels, and determine the warning level corresponding to the battery to be tested based on each expansion force peak value and the time corresponding to each expansion force peak value.

2. The battery thermal runaway expansion force feature identification and early warning method according to claim 1, characterized in that: Different warning levels are preset, and the warning level of the battery to be tested is determined based on the peak values ​​of each expansion force and the corresponding time of each expansion force peak value, including: Presetting a first preset value and a second preset value; When the first expansion force peak is detected, a second-level warning is issued; When the second expansion force peak is detected, if the difference between the time corresponding to the first expansion force peak and the second expansion force peak is greater than or equal to the first preset value and less than the second preset value, a third-level warning is issued; If the difference between the time corresponding to the first expansion force peak and the second expansion force peak is less than a first preset value, a level 4 warning is issued; When the third expansion force peak is detected, a level 5 warning is issued.

3. The battery thermal runaway expansion force feature identification and early warning method according to claim 1, characterized in that: The obtaining of the current expansion force value of the battery to be tested includes: The current expansion force value is obtained by setting a pressure sensor on the battery to be tested.

4. The battery thermal runaway expansion force feature identification and early warning method according to claim 1, characterized in that: k is negatively correlated with the real-time SOC of the battery under test.

5. A battery thermal runaway expansion force feature recognition and early warning system, used to implement a battery thermal runaway expansion force feature recognition and early warning method according to any one of claims 1 to 4, characterized in that: Includes the following modules: Preset module: preset thresholds and initial expansion force values ​​according to the changing characteristics of the expansion force during the charge and discharge process of the battery at different current rates; Calculation module: connected to the preset module, used to charge and discharge the battery under test at a preset current rate or let it stand to obtain the current expansion force value of the battery under test; determine the relationship between the current expansion force value of the battery and the threshold value. If the current expansion force value is greater than or equal to the threshold value, a level 1 warning is issued and the warning module is entered; Otherwise, repeat the calculation in the calculation module; An early warning module is connected to the calculation module and is used to calculate each expansion force peak value and the time corresponding to each expansion force peak value based on the current expansion force value and the initial expansion force value of the battery under test using a peak search algorithm; the expansion force peak values ​​include a first expansion force peak value, a second expansion force peak value, and a third expansion force peak value; Different warning levels are preset, and the warning level corresponding to the battery to be tested is determined based on each expansion force peak value and the time corresponding to each expansion force peak value.

6. An electronic device, characterized in that: The electronic device comprises: processor and memory; The processor is configured to execute the steps of a method for identifying and warning of battery thermal runaway expansion force characteristics as described in any one of claims 1 to 4 by calling the program or instructions stored in the memory.

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