Battery thermal runaway expansive force characteristic identification and early warning method, system and equipment

Abstract

The invention relates to the technical field of batteries, and discloses a battery thermal runaway expansive force characteristic identification and early warning method, system and device, and the method comprises the steps: presetting a threshold value and an initial expansive force value according to the change characteristics of the expansive force of a battery in the charging and discharging process under different current rates; charging and discharging or standing the to-be-detected battery at a preset current rate to obtain a current expansion force value of the to-be-detected battery; judging the size relationship between the current expansive force value of the battery to be detected and the threshold value, and if the current expansive force value is greater than or equal to the threshold value, performing primary early warning and entering the next step; otherwise, entering the previous step; calculating each expansion force peak value and 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; presetting different early warning levels, and judging an early warning level corresponding to the to-be-detected battery; and performing different early warning according to the early warning level. According to the invention, an alarm signal is given as early as possible before obvious thermal runaway of the battery occurs, and early warning is carried out on the harmfulness degree of the battery.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method, system and device for identifying and warning of battery thermal runaway expansion force characteristics. Background Art

[0002] Affected by environmental pollution, energy shortage, greenhouse effect, etc., the new energy vehicle industry has developed rapidly in recent years around the world. However, the number of new energy vehicle fire accidents has also been increasing, which has become one of the biggest obstacles to the commercialization of electric vehicles.

[0003] To solve the safety problem of lithium-ion batteries, it is necessary to optimize from different dimensions such as battery key material design, battery cell design, battery cell manufacturing process control, battery system integration, safety test verification and safety warning. Since the internal lithium-ion battery is an extremely complex electrochemical system, the normal charging and discharging process and thermal runaway process are accompanied by the interaction of different processes such as electricity, heat, chemistry, mechanics and gas production dynamics.

[0004] For thermal runaway warning, the commonly used methods are mainly based on voltage, temperature, internal resistance, released gas, smoke, etc. For these methods, when the battery reaches the set conditions, obvious thermal runaway has occurred, so it is impossible to react to the battery status in time; when thermal runaway occurs, the expansion force is a quantity that reacts to the temperature change and chemical reaction inside the battery. The expansion force signal appears earlier than traditional warning signals such as voltage and temperature, and will produce complex characteristics as the thermal runaway progresses. Therefore, the thermal runaway state can be judged based on the change in expansion force. However, in order to apply the expansion force signal in the power battery management system of electric vehicles, it is necessary to further develop relevant feature capture methods and perform graded warnings for thermal runaway based on the captured features. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method, system and device for identifying and warning of battery thermal runaway expansion force characteristics, which can give an alarm signal as early as possible before the battery has obvious thermal runaway, and warn of the degree of harmfulness of the battery, thereby providing sufficient time for active heat dissipation and active gas release at the battery system level, and personnel escape, thereby improving the application safety level of electric vehicles.

[0006] In a first aspect, the present invention provides a method for identifying and warning of battery thermal runaway expansion force characteristics, comprising the following steps:

[0007] 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;

[0008] S2, charging and discharging the battery to be tested at a preset current rate or leaving it at rest to obtain the current expansion force value of the battery to be tested;

[0009] S3, judging the relationship between the current expansion force value of the battery to be tested 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 goes to S4; otherwise, the process goes to S2;

[0010] S4, calculating each expansion force peak value and the time corresponding to each expansion force peak value using a peak value search algorithm according to the current expansion force value and the initial expansion force value of the battery to be tested; 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;

[0011] S5. Different warning levels are preset, and the warning level corresponding to the battery to be tested is determined according to each expansion force peak value and the time corresponding to each expansion force peak value.

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

[0013] 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;

[0014] S42, determining the relationship between the current expansion force value and the expansion force values ​​before k seconds and after k seconds. If the current expansion force value is greater than or equal to the expansion force value before k seconds and greater than or equal to the expansion force value after k seconds, the current expansion force value is the expansion force peak value; otherwise, the current expansion force value is not the expansion force peak value.

[0015] S43: If the current expansion force value is less than the initial expansion force value, the process ends; if the current expansion force value is greater than or equal to the initial expansion force value, the process proceeds to S41.

[0016] Furthermore, different warning levels are preset, and the warning level corresponding to the battery to be tested is determined according to each expansion force peak value and the time corresponding to each expansion force peak value, including:

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

[0018] When the first expansion force peak is detected, a second-level warning is issued;

[0019] 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;

[0020] If the difference between the time corresponding to the first expansion force peak value and the second expansion force peak value is less than the first preset value, a fourth-level warning is issued;

[0021] When the third expansion force peak is detected, a level 5 warning is issued.

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

[0023] Further, the obtaining of 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 positively correlated with the real-time SOC of the battery to be tested.

[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 threshold value and initial expansion force value according to the change characteristics of 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 or leave the battery under test at a preset current rate to obtain the current expansion force value of the battery under test; judge 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, issue a first-level warning and enter the warning module; otherwise, repeat the calculation in the calculation module;

[0029] Early warning module: connected to the calculation module, used to calculate 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 a peak search algorithm; 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; different early warning levels are preset, and the early warning level corresponding to the battery to be tested is judged according to each expansion force peak value and the time corresponding to 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 used 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] This application aims at the multiple jet fire characteristics existing in the process of battery thermal runaway, and then at the multiple expansion force peak characteristics associated with this characteristic, proposes a peak finding algorithm for the expansion force peak, and performs graded warnings on the thermal runaway state according to whether the peak appears, the time interval between occurrences, and the number of occurrences. Each level indicates the hazard of the thermal runaway state and accurately responds to the development of the battery inside, so that personnel can have an accurate grasp of the battery status, reduce decision-making errors caused by misjudgment, reduce losses, and improve the application safety level of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 is a flow chart of a method for identifying and warning of battery thermal runaway expansion force characteristics provided by an embodiment of the present invention;

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

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

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

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

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

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0042] First, the following instructions are given:

[0043] Thermal runaway is an abnormal phenomenon that occurs in batteries under specific conditions, involving a sharp rise in internal battery temperature, accelerated chemical reactions, and the generation and accumulation of gas. These phenomena interact with each other, forming a vicious cycle that can lead to battery failure or even explosion.

[0044] During thermal runaway, the temperature and pressure inside the battery rise sharply, leading to thermal expansion of battery materials and electrolytes, as well as the generation and accumulation of gas. These phenomena work together to produce significant expansion force. When the expansion force exceeds the bearing capacity of the battery explosion-proof valve or shell, it will cause the battery explosion-proof valve or shell to rupture and the sudden release of gas. The sudden release of gas forms a jet fire, posing a serious threat to the battery and the surrounding environment.

[0045] Example 1

[0046] Research has found that when external heating of the battery triggers thermal runaway, gas is generated inside the battery and the positive and negative electrodes expand, which increases the battery expansion force. When the battery expansion force is less than the opening pressure of the battery pressure relief valve, the expansion force continues to increase and there is a threshold, and the detection of the threshold is usually earlier than the change of battery voltage and battery temperature.

[0047] When the internal pressure of the battery is greater than the opening pressure of the battery pressure relief valve, the explosion-proof valve opens and the expansion force reaches its first expansion force peak; thereafter, as the battery experiences multiple jet fires, the expansion force reaches multiple peaks; the threshold and the first expansion force peak are used for thermal runaway warning, with high advance time; multiple peaks are used for hazard degree warning, with high accuracy.

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

[0049] Figure 1 is a flow chart of a method for identifying and warning the characteristics of thermal runaway expansion force of a battery provided by an embodiment of the present invention. Figure 1 , including:

[0050] 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.

[0051] The battery is charged and discharged at different current rates to obtain the expansion force variation characteristics of the battery. A threshold is set according to the expansion force variation characteristics. If the threshold is exceeded, thermal runaway is more likely to occur. For example, the threshold may be 4000N.

[0052] The initial expansion force value is the expansion condition of the battery under normal conditions.

[0053] 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. The current expansion force value can be obtained by setting a pressure sensor on the battery under test.

[0054] It should be noted that, when the condition of “charging and discharging at a preset current rate or standing still” is satisfied, there is no specific limitation on the state of the battery SOC, etc., and the actual expansion force of the battery can be directly monitored.

[0055] S3, judging the relationship between the current expansion force value of the battery to be tested 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 goes to S4; otherwise, the process goes to S2.

[0056] When the real-time expansion force is greater than or equal to the threshold, the battery shell may swell significantly, which may cause the battery module connector to deform and there is a risk of local arcing. At this time, the probability of thermal runaway is high, and a first-level warning is issued to remind nearby personnel to evacuate as soon as possible.

[0057] If the expansion force increases further and reaches a peak value, thermal runaway will occur and jet fire will be ejected, so the peak value of the expansion force needs to be monitored.

[0058] S4. Calculate each expansion force peak value and the time corresponding to each expansion force peak value using a peak value search algorithm according to the current expansion force value and the initial expansion force value of the battery to be tested; 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, which are the first, second and third peak values ​​detected respectively.

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

[0060] 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;

[0061] S42, determining the relationship between the current expansion force value and the expansion force values ​​before k seconds and after k seconds. If the current expansion force value is greater than or equal to the expansion force value before k seconds and greater than or equal to the expansion force value after k seconds, 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 occur, 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 in the previous k seconds or less than the swelling force value in the next k seconds;

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

[0065] 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, go to S41.

[0066] The above peak judgment process determines the peak value by setting a window, that is, the time of the previous k seconds and the next k seconds of the real-time swelling value, and judging whether the current swelling force value is the largest within this window range. The size of k here depends on the real-time SOC of the battery to be tested. The larger the SOC, the smaller k is, that is, the two are positively correlated. Exemplarily, 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. It can be set according to the actual situation, and the present application will not elaborate too much.

[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. Therefore, the search for the peak value is stopped. When the real-time swelling force exceeds the threshold again, the peak value search algorithm is used to judge the peak value.

[0068] S5. Preset different warning levels, and judge 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, preset a first preset value and a second preset value, and the specific values can be set according to actual requirements; when the first swelling force peak value is detected, that is, when the first detected swelling force peak value appears, a secondary warning is given; when a peak value appears, it indicates that the battery has experienced thermal runaway. At this time, the battery may have the explosion-proof valve opened, and a large amount of aerosol, smoke is discharged or there is a violent jet fire; the discharged substances are likely to cause a short circuit outside the battery, overheating of adjacent batteries, and the failure of the high-voltage insulation protection inside the battery system.

[0070] When the second expansion force peak is detected, that is, 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; illustratively, the first preset value is 2.5 seconds and the second preset value is 15 seconds. At this time, due to the secondary aerosol, smoke or jet fire spraying in the battery, the possibility of heat diffusion in the battery system is higher, so the risk is greater. 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 second preset value, no warning is issued;

[0071] If the difference between the time corresponding to the first expansion force peak and the second expansion force peak is less than the first preset value, a fourth-level warning is issued; 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. The smaller the interval time, the more likely it is that a secondary jet fire will occur in a short period of time, and the challenges brought by battery pack pressure relief, cooling and arc avoidance will be greater, thus posing a higher risk.

[0072] When the third expansion force peak is detected, a level 5 warning is issued. At this time, the battery thermal runaway reaction is a continuous and long process, and the multiple jet fires corresponding to the multiple peaks will cause multiple extrusions and thermal shocks to the adjacent batteries, which is more likely to cause thermal diffusion in the adjacent batteries, and at the same time, it makes it more difficult to eliminate the risk of battery thermal runaway through external fire extinguishing measures.

[0073] It should be noted that the expansion force shown by the fourth peak, the fifth peak, etc. is insufficient, which is similar to the situation of the third expansion force peak, and the early warning effect is also the same. Therefore, this application is limited to the monitoring of the third expansion force peak.

[0074] In addition, this application also includes: taking different measures according to different warning levels:

[0075] The measures that can be taken are: cut off the power of the battery, control the power of the fan and water pump to the highest level, and force the battery to dissipate heat; among them, for the air cooling system, control the power of the fan, etc. to the highest level to force the battery to dissipate heat, and increase the air convection rate inside the battery system to discharge the generated aerosols, smoke, etc. out of the battery system box to minimize the occurrence of thermal runaway; start the fire extinguishing system to spray fire retardant on the battery, retard possible fire and combustion in the battery system, and use sound and light to alarm, etc.; just make the settings according to the actual situation, and this application will not explain in detail.

[0076] In summary, this application uses the expansion force peak as the judgment condition to quantify the thermal runaway state of the battery, and divides the warning level according to the peak value, thereby grading the degree of thermal runaway hazard of the battery; from level 2 to level 5, the degree of hazard increases, so corresponding fire-fighting measures are taken in time to reduce the risk.

[0077] Example 2

[0078] Based on Example 1, this application provides a specific implementation to illustrate Example 1:

[0079] 1) Conduct thermal runaway tests on lithium-ion batteries. The lithium-ion batteries are 51Ah square hard-shell ternary / graphite batteries. External heating is used to trigger thermal runaway of the battery to more realistically 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 tabs and the shell temperature, which is obtained by a temperature sensor; the voltage is the voltage of the positive and negative terminals of the battery, which is obtained by a voltage sensor; the battery expansion force is the expansion force of the side of the square hard shell, which is obtained by a pressure sensor. In the battery system, the pressure sensor can be arranged in a single battery module to obtain the overall expansion force of the battery module, or by arranging it on the side of a single battery cell to obtain the expansion force value of each cell; the battery thermal runaway combustion image is collected by a camera.

[0082] The peak values ​​of battery expansion force data under different SOC are found. The expansion force peaks found 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 7222.6N, and the interval between the first expansion force peak and the second expansion force peak is 2.26s.

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

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

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

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

[0088] At the same time, before the first expansion force peak value appears, when the expansion force reaches 4000N, the expansion force curve has shown a drastic change, and then quickly reaches the first expansion force peak value, which proves the feasibility of the threshold value of 4000N set in Example 1 of the present application.

[0089] Example 3

[0090] Based on the content of Example 1, the present application provides a battery thermal runaway expansion force feature recognition and early warning system, including:

[0091] Preset module: preset threshold value and initial expansion force value according to the change characteristics of expansion force during the charge and discharge process of the battery at different current rates;

[0092] Calculation module: connected to the preset module, used to charge and discharge or leave the battery under test at a preset current rate to obtain the current expansion force value of the battery under test; judge 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, issue a first-level warning and enter the warning module; otherwise, repeat the calculation in the calculation module;

[0093] Early warning module: connected to the calculation module, used to calculate 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 a peak search algorithm; 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; different early warning levels are preset, and the early warning level corresponding to 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] For other contents, please refer to Example 1, which will not be described in detail here.

[0095] Example 4

[0096] The present application provides an electronic device, comprising: a processor and a memory; the processor calls a program or instruction stored in the memory to execute the steps of a battery thermal runaway expansion force feature identification and early warning method as described in Example 1.

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

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

[0099] In addition to the above-mentioned methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of a battery thermal runaway expansion force characteristic identification and early warning method provided in any embodiment of the present application.

[0100] The computer program product may be written in any combination of one or more programming languages ​​to write program codes for performing the operations of the embodiments of the present application, 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 may be executed entirely on the user computing device, partially on the user device, as an independent 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, an embodiment of the present application may also be a computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor executes the steps of a battery thermal runaway expansion force characteristic identification and early warning method provided in any embodiment of the present application.

[0102] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with 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 above.

[0103] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0104] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying and warning the characteristics of thermal runaway expansion force of a battery, 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, charging and discharging the battery to be tested at a preset current rate or leaving it at rest to obtain the current expansion force value of the battery to be tested; S3, judging the relationship between the current expansion force value of the battery to be tested 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 goes to S4; Otherwise, go to S2; S4, calculating each expansion force peak value and the time corresponding to each expansion force peak value using a peak value search algorithm according to the current expansion force value and the initial expansion force value of the battery to be tested; 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; S5. Different warning levels are preset, and the warning level corresponding to the battery to be tested is determined according to each expansion force peak value and the time corresponding to each expansion force peak value.

2. The method for identifying and warning the thermal runaway expansion force characteristics of a battery according to claim 1, characterized in that: The use of a peak value search algorithm to calculate each expansion force peak value comprises: 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, determining the relationship between the current expansion force value and the expansion force values ​​before k seconds and after k seconds. If the current expansion force value is greater than or equal to the expansion force value before k seconds and greater than or equal to the expansion force value after k seconds, the current expansion force value is the expansion force peak value; otherwise, the current expansion force value is not the expansion force peak value. S43: If the current expansion force value is less than the initial expansion force value, the process ends; if the current expansion force value is greater than or equal to the initial expansion force value, the process proceeds to S41.

3. The method for identifying and warning the thermal runaway expansion force characteristics of a battery according to claim 1, characterized in that: Different warning levels are preset, and the warning level corresponding to the battery to be tested is determined according to each expansion force peak value and the time corresponding to 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 value and the second expansion force peak value is less than the first preset value, a fourth-level warning is issued; When the third expansion force peak is detected, a level 5 warning is issued.

4. The method for identifying and warning the thermal runaway expansion force characteristics of a battery 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.

5. The method for identifying and warning the thermal runaway expansion force characteristics of a battery according to claim 2, characterized in that: k is positively correlated with the real-time SOC of the battery to be tested.

6. A battery thermal runaway expansion force feature recognition and early warning system, used to execute a battery thermal runaway expansion force feature recognition and early warning method as described in any one of claims 1 to 5, characterized in that: Includes the following modules: Preset module: preset threshold value and initial expansion force value according to the change characteristics of 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 or leave the battery under test at a preset current rate to obtain the current expansion force value of the battery under test; judge the relationship between the current expansion force value of the battery and the threshold value, and if the current expansion force value is greater than or equal to the threshold value, issue a first-level warning and enter the warning module; Otherwise, repeat the calculation in the calculation module; Early warning module: connected to the calculation module, used to calculate each expansion force peak value and the time corresponding to each expansion force peak value by using a peak value search algorithm according to 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; Different warning levels are preset, and the warning level corresponding to the battery to be tested is determined according to each expansion force peak value and the time corresponding to each expansion force peak value.

7. An electronic device, characterized in that: The electronic device comprises: Processor and memory; The processor is used to execute the steps of a battery thermal runaway expansion force feature identification and early warning method as described in any one of claims 1 to 5 by calling the program or instructions stored in the memory.

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