Battery safety degree estimation method, system, vehicle, and electronic device

Abstract

The application relates to the technical field of vehicles and provides a battery safety degree estimation method, a battery safety degree estimation system, a vehicle and an electronic device.The method comprises the following steps: obtaining the current temperature of a battery; based on the current temperature, a corresponding convective heat transfer coefficient is called from a set of convective heat transfer coefficients of the battery; based on the convective heat transfer coefficient and a heat generation rate model of the battery, the temperature of the battery at the next moment is estimated as an estimated temperature; the actual temperature of the battery at the next moment is obtained; and based on the estimated temperature and the actual temperature, the safety degree of the battery is determined.The application is used to solve the defect that the controllability of the battery use safety risk is low due to the lack of an online real-time accurate determination method for the safety degree of the battery in the prior art, realize online intuitive estimation of the safety degree of the battery, and determine the safety degree of the battery in the whole life cycle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a battery safety degree estimation method and system, a vehicle and an electronic device. BACKGROUND

[0002] With the rapid development and application of vehicles, the safety of batteries has been an important concern of the industry and academia. In view of the safety accidents of batteries, the essence can be summarized as follows: under abnormal use conditions such as overcharging, overheating, impact and short circuit, a series of chemical reactions in the battery are triggered due to abnormal temperature rise, which causes the battery to expand, smoke, safety valve to open, etc. At the same time, these reactions release a large amount of heat, further increasing the temperature of the entire battery, and eventually causing a series of chemical reactions to occur violently, the temperature of the battery rises uncontrollably and rapidly, causing combustion or explosion, resulting in serious safety accidents. This process is also known as "thermal runaway" of the battery. As can be seen, there are multiple important chemical reactions in the process from abnormal temperature rise to "thermal runaway" of the battery, and this process is closely related to temperature.

[0003] However, in the process of implementing the present application, the inventors have found that the current battery safe use temperature boundary cannot be accurately obtained through offline tests, and therefore, how to accurately determine the safety degree of the battery in real time online is a problem to be solved. SUMMARY

[0004] The present application provides a battery safety degree estimation method and system, a vehicle and an electronic device, which aims to at least solve one of the technical problems existing in the prior art or related art.

[0005] The present application provides a battery safety degree estimation method, comprising:

[0006] obtaining a current temperature of the battery;

[0007] based on the current temperature, retrieving a corresponding convective heat transfer coefficient from a set of convective heat transfer coefficients of the battery;

[0008] based on the convective heat transfer coefficient and a heat generation rate model of the battery, estimating the temperature of the battery at the next time as an estimated temperature;

[0009] obtaining an actual temperature of the battery at the next time;

[0010] based on the estimated temperature and the actual temperature, determining the safety degree of the battery.

[0011] Preferably, the battery safety degree estimation method according to the present application further comprises a construction method of the set of convective heat transfer coefficients.

[0012] The construction method comprises:

[0013] constructing a temperature database of the battery;

[0014] determining, based on current-temperature corresponding data in the temperature database, a convective heat transfer coefficient of the battery at different temperatures by using an electrochemical thermal model of the battery;

[0015] obtaining the set of convective heat transfer coefficients based on the convective heat transfer coefficient.

[0016] Preferably, the battery safety degree estimation method according to the present application, the constructing a temperature database of the battery, comprises:

[0017] determining whether a difference between a preset charging current and an actual charging current of the battery satisfies a first preset deviation threshold;

[0018] if yes, recording the current-temperature corresponding data of the battery at different temperatures when charging from SOC 0% to SOC 100%, and the charging temperature covers a preset temperature threshold range;

[0019] obtaining the temperature database of the battery based on the current-temperature corresponding data.

[0020] Preferably, the battery safety degree estimation method according to the present application, the determining, based on current-temperature corresponding data in the temperature database, a convective heat transfer coefficient of the battery at different temperatures by using an electrochemical thermal model of the battery, comprises:

[0021] fitting the current-temperature corresponding data in the temperature database by using a least square method;

[0022] determining a preselected convective heat transfer coefficient by using the electrochemical thermal model of the battery based on the fitted current-temperature corresponding data;

[0023] determining the preselected convective heat transfer coefficient satisfying a deviation requirement based on a second preset deviation threshold;

[0024] when the preselected convective heat transfer coefficient satisfying the deviation requirement reaches a preset number, removing the maximum and minimum values of the preselected convective heat transfer coefficient satisfying the deviation requirement, and calculating an average value of the remaining preselected convective heat transfer coefficients satisfying the deviation requirement;

[0025] taking the average value as the convective heat transfer coefficient.

[0026] Preferably, the battery safety degree estimation method according to the present application, the determining, based on the estimated temperature and the actual temperature, a safety degree of the battery, comprises:

[0027] correct the estimated temperature based on a temperature correction coefficient, the temperature correction coefficient being used to correct deviation of the estimated temperature;

[0028] determine whether the actual temperature is greater than or equal to the corrected estimated temperature;

[0029] if greater, determine that the battery has a safety risk, and execute a preset battery protection strategy;

[0030] if less than or equal to, determine that the temperature of the battery is normal.

[0031] Preferably, the battery safety degree estimation method according to the present application further comprises: a method for obtaining the temperature correction coefficient;

[0032] The method for obtaining comprises:

[0033] obtain the temperature of the battery when the battery is in a low-voltage power-on stage;

[0034] determine the corresponding convective heat transfer coefficient based on the temperature of the battery;

[0035] determine a temperature estimation value of the battery based on the convective heat transfer coefficient and a heat generation rate model of the battery;

[0036] use the ratio of the temperature estimation value to the temperature of the battery as the temperature correction coefficient;

[0037] when the battery is in a high-voltage power-on stage and / or a charging stage, and the temperature of the battery is determined to be normal, update the temperature correction coefficient based on the ratio of the estimated temperature to the actual temperature, and use the updated temperature correction coefficient to correct the estimated temperature in the next time and the next time.

[0038] The present application also provides a battery safety degree estimation system, comprising: a first temperature acquisition module, a coefficient determination module, a temperature estimation module, a second temperature acquisition module and a safety degree determination module; wherein,

[0039] the first temperature acquisition module is used to acquire the current temperature of the battery;

[0040] the coefficient determination module is connected to the first temperature acquisition module, and is used to, based on the current temperature, call the corresponding convective heat transfer coefficient from a set of convective heat transfer coefficients of the battery;

[0041] the temperature estimation module is connected to the coefficient determination module, and is used to, based on the convective heat transfer coefficient and a heat generation rate model of the battery, estimate the temperature of the battery in the next time as an estimated temperature;

[0042] The second temperature obtaining module is configured to obtain an actual temperature of the battery at the next time point;

[0043] The safety degree determining module is connected to the temperature estimating module and the second temperature obtaining module respectively, and is configured to determine the safety degree of the battery based on the estimated temperature and the actual temperature.

[0044] The present application further provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the battery safety degree estimation method according to any one of the above.

[0045] The present application further provides a non-transitory computer readable storage medium having a computer program stored thereon, wherein the computer program is executable by a processor to implement the battery safety degree estimation method according to any one of the above.

[0046] The present application further provides a vehicle comprising a vehicle body and a battery, and further comprising the battery safety degree estimation system according to the above, or the battery is estimated in safety degree by the battery safety degree estimation method according to any one of the above; or the electronic device according to the above; or the readable storage medium according to the above.

[0047] The present application provides a battery safety degree estimation method, system, vehicle and electronic device, which obtains the current temperature of the battery, then based on the current temperature of the battery, retrieves the corresponding convective heat transfer coefficient from the set of convective heat transfer coefficients of the battery, to estimate the temperature of the battery at the next time point based on the retrieved convective heat transfer coefficient and the heat generation rate model of the battery, and finally determines the safety degree of the battery based on the estimated temperature and the actual temperature of the battery. That is, by estimating the temperature of the battery at the next time point and the actual temperature, the online intuitive estimation of the safety degree of the battery is realized, and the safety degree of the battery in the whole life cycle can be determined, thereby effectively ensuring the safety of the battery and prolonging the service life. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0049] Figure 1 is a flowchart of a battery safety degree estimation method according to an embodiment of the present application;

[0050] Figure 2is a flowchart of constructing a temperature database of a battery according to an embodiment of the present application;

[0051] Figure 3 is a flowchart of determining the convective heat transfer coefficient of a battery at different temperatures based on the current value and temperature value in the temperature database, and using the electrochemical heat model of the battery according to an embodiment of the present application;

[0052] Figure 4 is a flowchart of battery safety estimation using the battery safety estimation method according to an embodiment of the present application;

[0053] Figure 5 is a structural diagram of a battery safety estimation system according to an embodiment of the present application;

[0054] Figure 6 is a structural diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than 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 fall within the scope of protection of the present application.

[0056] The present application will be described below with reference to the drawings. Figures 1 to 4 A battery safety estimation method is described in the present application, which can be executed by the battery management system (BMS) of a battery, or the software and / or hardware in an electronic device such as a computer, tablet, mobile phone, etc. in communication connection with the BMS. As shown in the figure, the method comprises the following steps: Figure 1

[0057] 101. Obtain the current temperature of the battery;

[0058] It can be understood that, in order to meet the requirement of output voltage, a battery is generally composed of multiple battery monomers through series and parallel connection. The purpose of obtaining the temperature of the battery in the present embodiment is to determine whether the temperature of the battery is abnormal, and thus to affect the safety of the battery. Therefore, it should be noted that the current temperature, actual temperature, etc. of the battery mentioned in the present embodiment refer to the temperature of the battery monomer with the highest temperature in the battery.

[0059] 102. Based on the current temperature, the corresponding convective heat transfer coefficient is retrieved from the set of convective heat transfer coefficients of the battery; ​

[0060] Specifically, the temperature rise of the battery during charging and discharging is related to the heat generated by the electrochemical reaction and the heat exchange with the external environment, and therefore, in order to ensure the accuracy of the temperature prediction of the battery at the next moment, it is necessary to determine the convective heat transfer coefficient of the battery at the current temperature.

[0061] 103. Based on the convective heat transfer coefficient and the heat generation rate model of the battery, the temperature of the battery at the next moment is predicted as the predicted temperature.

[0062] Specifically, the heat generation rate model can be selected as the Bernardi model shown in formula 1, which can consider reversible heat and irreversible heat respectively, and establish the relationship between the heat generation rate and the system macroscopic measurement parameters:

[0063]

[0064] Wherein, Q is the heat generation rate, V b is the volume of the battery, E is the voltage of the battery, Eo is the open circuit voltage of the battery, T is the temperature of the battery. Based on the heat generation rate model, the heat generation rate of the battery can be calculated by the volume, current, voltage, internal resistance, temperature and temperature influence coefficient of the battery.

[0065] More specifically, the electrochemical heat model of the battery is shown in formula 2, after determining the heat generation rate Q and the convective heat transfer coefficient h of the battery, the temperature change of the battery can be determined based on the electrochemical heat model.

[0066]

[0067] Wherein, C is the specific heat capacity of the battery, m is the mass of the battery, Q is the heat generation rate, h is the convective heat transfer coefficient, s is the surface area of the battery, Tcell is the surface temperature of the battery, and Tenv is the ambient temperature.

[0068] Therefore, after determining the temperature change of the battery, the predicted temperature, i.e. the temperature of the battery at the next moment, can be further determined.

[0069] 104. Obtain the actual temperature of the battery at the next moment;

[0070] Specifically, at the next moment, the actual temperature of the battery can be obtained by a temperature sensor or the like.

[0071] 105. Based on the predicted temperature and the actual temperature, determine the safety degree of the battery.

[0072] It can be understood that the estimated temperature can be understood as the temperature that the battery can reach in the next moment when the battery is in a normal state, which is estimated based on the current environment in which the battery is located and the heat exchange characteristics and heat generation characteristics of the battery itself. Therefore, when the actual temperature deviates from the estimated temperature too much, it can be determined that the battery temperature is abnormal and there is a safety risk.

[0073] The battery safety degree estimation method provided by the embodiment of the present application can estimate the safety degree of the battery in real time and intuitively, and can realize safety judgment of the battery in the whole life cycle.

[0074] Based on the above-mentioned embodiment, the battery safety degree estimation method provided by the embodiment of the present application further comprises a construction method of the set of convective heat transfer coefficients.

[0075] The construction method comprises:

[0076] constructing a temperature database of the battery;

[0077] determining the convective heat transfer coefficients of the battery at different temperatures based on the current and temperature corresponding data in the temperature database and using the electrochemical heat model of the battery.

[0078] obtaining the set of convective heat transfer coefficients based on the convective heat transfer coefficients.

[0079] The temperature database stores the current and temperature data of the battery in the entire charging period from 0% to 100% of the SOC (state of charge) of the battery at various temperatures.

[0080] Specifically, by substituting the current and temperature data of the battery when charging at different temperatures into the electrochemical heat model of the battery shown in formula 2, the convective heat transfer coefficients at different temperatures can be determined. The set of these convective heat transfer coefficients is the set of convective heat transfer coefficients.

[0081] Based on the above-mentioned embodiment, the construction of the temperature database of the battery comprises:

[0082] determining whether the difference between the preset charging current and the actual charging current of the battery satisfies a first preset deviation threshold;

[0083] If it is satisfied, the current and temperature corresponding data of the battery from 0% to 100% of the SOC when charging at different temperatures are recorded, and the charging temperature covers a preset temperature threshold range.

[0084] Based on the current and temperature corresponding data, the temperature database of the battery is obtained.

[0085] Specifically, before recording the current and temperature corresponding data of the battery when charging at different temperatures, first determine whether the difference between the actual charging current of the battery and the preset charging current meets the first preset deviation threshold, i.e. whether the output capability of the charging power supply such as the charging pile meets the preset charging requirement, which can improve the accuracy of the obtained current and temperature corresponding data.

[0086] More specifically, the first preset deviation threshold can be set according to experience and demand, etc., for example, it can be set to 4A, 5A, 6A, etc.

[0087] Further, by setting the preset temperature threshold range, the constructed temperature database can cover the current and temperature corresponding data of the battery when charging at any temperature within the preset temperature threshold range, thereby ensuring the comprehensiveness of the data.

[0088] In one embodiment, because the working environment temperature range of the current vehicle is generally between -20-45℃, the preset temperature threshold range can be set to -20-45℃. At the same time, assuming that the first preset deviation threshold is 5A, the process of constructing the temperature database of the battery is as shown in Figure 2 , including the following steps:

[0089] 201, start charging;

[0090] 202, determine whether the SOC is equal to 0%; if yes, go to step 203; if no, go to step 208;

[0091] 203, determine whether the charging temperature is between -20-45℃; if yes, go to step 204; if no, go to step 208;

[0092] 204, determine whether the difference between the preset charging current and the actual charging current is less than 5A; if yes, go to step 205; if no, go to step 208;

[0093] 205, record the current and temperature corresponding data;

[0094] 206, determine whether the SOC is equal to 100%; if yes, go to step 207; if no, return to step 205;

[0095] 207, stop recording and store in the temperature database;

[0096] 208, stop recording.

[0097] Based on the content of the above embodiment, based on the current value and temperature value in the temperature database, the convective heat transfer coefficient of the battery at different temperatures is determined by using the electrochemical heat model of the battery, including:

[0098] fitting the current and temperature corresponding data in the temperature database by using a least square method;

[0099] determining a preselected convection heat transfer coefficient based on the fitted current and temperature corresponding data by using an electrochemical thermal model of the battery;

[0100] determining the preselected convection heat transfer coefficient meeting the deviation requirement based on a second preset deviation threshold;

[0101] when the preselected convection heat transfer coefficient meeting the deviation requirement reaches a preset number, removing the maximum and minimum values of the preselected convection heat transfer coefficient meeting the deviation requirement, and calculating an average value of the remaining preselected convection heat transfer coefficient meeting the deviation requirement;

[0102] taking the average value as the convection heat transfer coefficient.

[0103] In the battery safety degree estimation method provided in the embodiments, on one hand, the current and temperature corresponding data are fitted online by using a least square method, and then the fitting degree and fitting times are determined based on a standard deviation, i.e., a second preset deviation threshold, so that the rationality of the fitted convection heat transfer coefficient in the same temperature region can be determined, and the accuracy of the obtained convection heat transfer coefficient is improved; on the other hand, the number of the obtained preselected convection heat transfer coefficient is set, and then the final convection heat transfer coefficient is determined based on an average value method, so that the accuracy of the determined convection heat transfer coefficient is further improved.

[0104] In one embodiment, still taking the preset temperature threshold range of -20-45℃ as an example, assuming that the second preset deviation threshold is 0.5% and the preset number is 10, the process of determining the convection heat transfer coefficient of the battery at different temperatures based on the current value and the temperature value in the temperature database by using the electrochemical thermal model of the battery is as shown in Figure 3 , which includes the following steps:

[0105] 301, determining the temperature and the charging current;

[0106] 302, determining whether the temperature is in the range of -20-45℃; if yes, going to step 303; if no, going to step 310;

[0107] 303, inputting the current and temperature corresponding data into the electrochemical thermal model;

[0108] 304, determining the convection heat transfer coefficient;

[0109] 305, determining whether the deviation between the obtained convection heat transfer coefficients is less than 0.5%; if yes, going to step 306; if no, going to step 310;

[0110] 306, adding 1 to the fitting times;

[0111] 307、determine whether the fitting times reach 10 times; if yes, go to step 308; if no, return to step 303;

[0112] 308、determine the average value of the 8 convective heat transfer coefficients after removing the maximum value and the minimum value of the convective heat transfer coefficients;

[0113] 309、store the average value as the convective heat transfer coefficient in the convective heat transfer coefficient set;

[0114] 310、end the fitting.

[0115] Based on the content of the above embodiment, the safety degree of the battery is determined based on the estimated temperature and the actual temperature, including:

[0116] The estimated temperature is corrected based on a temperature correction coefficient, and the temperature correction coefficient is used to correct the deviation of the estimated temperature;

[0117] It is determined whether the actual temperature is greater than or equal to the corrected estimated temperature;

[0118] If greater, it is determined that the battery has a safety risk, and a preset battery protection strategy is executed;

[0119] If less than or equal to, it is determined that the temperature of the battery is normal.

[0120] Specifically, the corrected estimated temperature Ty can be obtained by the correction method shown in formula 3:

[0121] Ty=k*Tc+b (3)

[0122] Wherein, k is a temperature correction coefficient, b is an empirical value, and Tc is an estimated temperature.

[0123] By correcting the estimated temperature based on the temperature correction coefficient k, the corrected estimated temperature can represent the temperature boundary of the battery in the current state, i.e. the highest temperature value that ensures the safe use of the battery. Therefore, when the actual temperature Tr of the battery is greater than k*Tc+b, it can be determined that the battery has a safety risk, triggering the preset battery protection strategy, which can avoid the heat runaway caused by the continuous rise of the battery temperature.

[0124] More specifically, the preset battery protection strategy can include a variety, so that different preset battery protection strategies can be triggered according to the specific situation of the battery, for example: when the battery is charging, the preset battery protection strategy corresponding to the actual temperature Tr of the battery exceeding Ty can be to suspend charging, reduce the charging current, etc.; when the battery is discharging, the preset battery protection strategy corresponding to the actual temperature Tr of the battery exceeding Ty can be to reduce the output power of the battery, suspend discharging, etc.

[0125] Based on the content of the above embodiments, the battery safety degree estimation method provided by the embodiments of the present application further comprises: a method for obtaining the temperature correction coefficient;

[0126] The method comprises:

[0127] When the battery is in a low-voltage power-on stage, the temperature of the battery is obtained;

[0128] Based on the temperature of the battery, the corresponding convective heat transfer coefficient is determined;

[0129] Based on the convective heat transfer coefficient and the heat generation rate model of the battery, the temperature estimation value of the battery is determined;

[0130] The ratio of the temperature estimation value to the temperature of the battery is taken as the temperature correction coefficient;

[0131] When the battery is in a high-voltage power-on stage and / or a charging stage, and the temperature of the battery is determined to be normal, the ratio of the estimated temperature to the actual temperature is used to update the temperature correction coefficient, which is used to correct the estimated temperature of the next moment.

[0132] It can be understood that taking the ratio of the model-based estimated battery temperature to the actual battery temperature as the temperature correction coefficient can correct the accuracy of the model-estimated temperature, so that it is closer to the actual temperature of the battery.

[0133] Specifically, when in the low-voltage power-on stage, there is basically no current flowing into or out of the battery, so the heat generated by the electrochemical reaction can be ignored, and the convective heat transfer with the environment is also relatively stable. At this time, based on the convective heat transfer coefficient and the heat generation rate model of the battery, the temperature estimation value of the battery is relatively accurate. Therefore, based on the ratio of the temperature estimation value to the obtained temperature, the temperature correction coefficient determined is relatively accurate, which can be used as a reference point for the temperature correction coefficient to correct the estimated temperature obtained based on the model in the high-voltage power-on stage or the charging stage, thereby improving the accuracy of the temperature value used to determine the safety degree of the battery.

[0134] More specifically, the heat generation rate model determines the estimated temperature of the battery at the next moment. When the actual temperature Tr of the battery at the next moment is less than or equal to k*Tc+b, on the one hand, it indicates that the battery state is normal, and on the other hand, the ratio of the actual temperature at the next moment to the determined estimated temperature at the next moment is used to update the temperature correction coefficient, so that the temperature correction coefficient can be updated continuously according to the working state of the battery, thereby continuously improving the accuracy of determining the safety degree of the battery.

[0135] In one embodiment, the flow of the battery safety estimation using the battery safety estimation method provided by the embodiments of the present application is as follows Figure 4As shown, comprising the following steps:

[0136] 401, low voltage power-on;

[0137] 402, obtain the battery temperature;

[0138] 403, determine the convective heat transfer coefficient;

[0139] 404, based on the convective heat transfer coefficient and the heat generation rate model, determine the temperature estimate;

[0140] 405, calculate the temperature correction coefficient;

[0141] 406, high voltage power-on or charging;

[0142] 407, battery safety degree estimation.

[0143] The battery safety degree estimation method provided by the above-mentioned embodiments of the application records the current and temperature corresponding data of the temperature in the preset temperature threshold range and the entire charging process of SOC 0% to 100%, constructs a temperature database, and provides data preparation for fitting the convective heat transfer coefficient at different temperatures; the least square method is used to fit the current and temperature corresponding data online, the standard deviation is used to determine the fitting degree and the fitting times, the rationality of fitting the convective heat transfer coefficient in the same temperature region is determined, and then the average method is used to output the final convective heat transfer coefficient under different temperature conditions; the ratio of the actual effective temperature to the estimated model temperature is used as the temperature correction coefficient k to correct the estimated temperature, which not only makes the temperature correction coefficient update throughout the battery life cycle and is simple to calculate and has more opportunities to update, but also improves the accuracy of determining the battery safety degree; by determining the temperature estimate, the temperature estimate Tc is compared with the actual temperature Tr, when Tr>k*Tc+b, the preset battery protection strategy is triggered, otherwise the temperature correction coefficient k is updated online in real time, which not only realizes real-time and accurate determination of the battery safety degree, but also realizes safety degree determination of the entire battery life cycle.

[0144] Next, a battery safety degree estimation system provided by the application will be described, and the battery safety degree estimation system described below can be correspondingly referred to the battery safety degree estimation method described above.

[0145] The battery safety degree estimation system described in the embodiments of the application, as shown, Figure 5 comprises a first temperature acquisition module 510, a coefficient determination module 520, a temperature estimation module 530, a second temperature acquisition module 540 and a safety degree determination module 350; wherein,

[0146] The first temperature acquisition module 510 is configured to acquire the current temperature of the battery;

[0147] The coefficient determination module 520 is connected with the first temperature acquisition module 510, and is configured to, based on the current temperature, call a corresponding convective heat transfer coefficient from a set of convective heat transfer coefficients of the battery;

[0148] The temperature estimation module 530 is connected with the coefficient determination module 520, and is configured to, based on the convective heat transfer coefficient and a heat generation rate model of the battery, estimate a temperature of the battery at a next time point as an estimated temperature;

[0149] The second temperature acquisition module 540 is configured to acquire an actual temperature of the battery at the next time point;

[0150] The safety degree determination module 550 is connected with the temperature estimation module 530 and the second temperature acquisition module 540 respectively, and is configured to, based on the estimated temperature and the actual temperature, determine a safety degree of the battery.

[0151] The battery safety degree estimation system provided by the embodiment of the application comprises the first temperature acquisition module 510, the coefficient determination module 520, the temperature estimation module 530, the second temperature acquisition module 540 and the safety degree determination module 550.

[0152] Optionally, the system further comprises a set construction module connected with the coefficient determination module 520.

[0153] The set construction module is configured to:

[0154] construct a temperature database of the battery;

[0155] based on current-temperature corresponding data in the temperature database, determine the convective heat transfer coefficients of the battery at different temperatures by using an electrochemical heat model of the battery;

[0156] based on the convective heat transfer coefficients, obtain the set of convective heat transfer coefficients.

[0157] Optionally, the set construction module is more specifically configured to:

[0158] determine whether a difference between a preset charging current and an actual charging current of the battery satisfies a first preset deviation threshold;

[0159] If yes, record the current and temperature corresponding data of the battery charged from SOC 0% to SOC 100% at different temperatures, and the charging temperature covers a preset temperature threshold range;

[0160] Based on the current and temperature corresponding data, obtain the temperature database of the battery.

[0161] Optionally, the coefficient determination module 520 is specifically configured to:

[0162] fit the current and temperature corresponding data in the temperature database by using the least square method;

[0163] Based on the fitted current and temperature corresponding data, determine a preselected convection heat transfer coefficient by using the electrochemical thermal model of the battery.

[0164] Based on a second preset deviation threshold, determine the preselected convection heat transfer coefficient that meets the deviation requirement;

[0165] When the preselected convection heat transfer coefficient that meets the deviation requirement reaches a preset number, remove the maximum and minimum values of the preselected convection heat transfer coefficient that meets the deviation requirement, and calculate the average value of the remaining preselected convection heat transfer coefficient that meets the deviation requirement;

[0166] The average value is used as the convection heat transfer coefficient.

[0167] Optionally, the safety degree determination module 550 is specifically configured to:

[0168] correct the estimated temperature based on a temperature correction coefficient, the temperature correction coefficient being used to correct the deviation of the estimated temperature;

[0169] determine whether the actual temperature is greater than or equal to the corrected estimated temperature;

[0170] If yes, determine that the battery has a safety risk, and execute a preset battery protection strategy;

[0171] If no, determine that the temperature of the battery is normal.

[0172] Optionally, the method further comprises a coefficient acquisition module;

[0173] The coefficient acquisition module is configured to:

[0174] acquire the temperature of the battery when the battery is in a low-voltage power-on stage;

[0175] determine the corresponding convection heat transfer coefficient based on the temperature of the battery;

[0176] determining a temperature estimation value of the battery based on the heat transfer coefficient and a heat generation rate model of the battery;

[0177] using a ratio of the temperature estimation value to the temperature of the battery as the temperature correction coefficient;

[0178] updating the temperature correction coefficient based on a ratio of the estimation temperature to the actual temperature and using the updated temperature correction coefficient for correction of the estimation temperature of the next time point in the next time point when the battery is in a high-voltage power-on stage and / or a charging stage and the temperature of the battery is determined to be normal.

[0179] Figure 6 An example of a schematic diagram of a physical structure of an electronic device is shown in Figure 6 The electronic device can include a processor 610, a communications interface 620, a memory 630, and a communications bus 640, wherein the processor 610, the communications interface 620, and the memory 630 can communicate with each other through the communications bus 640. The processor 610 can invoke a logical instruction in the memory 630 to execute a battery safety degree estimation method, the method comprising: obtaining a current temperature of a battery; based on the current temperature, calling a corresponding heat transfer coefficient from a set of heat transfer coefficients of the battery; based on the heat transfer coefficient and a heat generation rate model of the battery, estimating a temperature of the battery in a next time point as an estimation temperature; obtaining an actual temperature of the battery in the next time point; and based on the estimation temperature and the actual temperature, determining a safety degree of the battery.

[0180] In addition, the logical instruction in the memory 630 described above can be implemented in the form of a software functional unit and sold or used as an independent product, which can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0181] In another aspect, the present application also provides a computer program product, which comprises a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform a battery safety degree estimation method as described above, the method comprising: obtaining a current temperature of a battery; based on the current temperature, retrieving a corresponding convective heat transfer coefficient from a set of convective heat transfer coefficients of the battery; based on the convective heat transfer coefficient and a heat generation rate model of the battery, estimating a temperature of the battery at a next time instant as an estimated temperature; obtaining an actual temperature of the battery at the next time instant; and based on the estimated temperature and the actual temperature, determining a safety degree of the battery.

[0182] In another aspect, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement a battery safety degree estimation method, the method comprising: obtaining a current temperature of a battery; based on the current temperature, retrieving a corresponding convective heat transfer coefficient from a set of convective heat transfer coefficients of the battery; based on the convective heat transfer coefficient and a heat generation rate model of the battery, estimating a temperature of the battery at a next time instant as an estimated temperature; obtaining an actual temperature of the battery at the next time instant; and based on the estimated temperature and the actual temperature, determining a safety degree of the battery.

[0183] The embodiments of the present application also provide a vehicle, which comprises a vehicle body and a battery, and further comprises the battery safety degree estimation system as described in any of the above embodiments, or the battery uses the battery safety degree estimation method as described in any of the above embodiments to estimate a safety degree.

[0184] or the electronic device as described in the above embodiments;

[0185] or the readable storage medium as described in the above embodiments.

[0186] It can be understood that the vehicle comprising the battery safety degree estimation system as described in any of the above embodiments, or the electronic device or the readable storage medium, or the battery using the battery safety degree estimation method as described in any of the above embodiments to estimate a safety degree has all the advantages and technical effects of the battery safety degree estimation system, the electronic device, the readable storage medium or the battery safety degree estimation method as described in any of the above embodiments, which will not be repeated here.

[0187] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0188] Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software and the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0189] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of estimating safety of a battery, characterized by, include: Get the current temperature of the battery; Based on the current temperature, the corresponding convective heat transfer coefficient is retrieved from the set of convective heat transfer coefficients of the battery; Based on the convective heat transfer coefficient and the heat generation rate model of the battery, the temperature of the battery at the next moment is estimated and used as the estimated temperature. Obtain the actual temperature of the battery at the next moment; The safety level of the battery is determined based on the estimated temperature and the actual temperature. It also includes: a method for constructing the set of convective heat transfer coefficients; The construction method includes: Construct a temperature database for the battery; Based on the current and temperature data in the temperature database, the convective heat transfer coefficient of the battery at different temperatures is determined using the electrochemical thermal model of the battery. Based on the convective heat transfer coefficient, the set of convective heat transfer coefficients is obtained.

2. The battery safety estimation method according to claim 1, characterized in that, The construction of the temperature database for the battery includes: Determine whether the difference between the preset charging current and the actual charging current of the battery meets the first preset deviation threshold. If satisfied, record the current and temperature data corresponding to the charging of the battery from 0% SOC to 100% at different temperatures, where the charging temperature covers a preset temperature threshold range; Based on the current and temperature data, the temperature database of the battery is obtained.

3. The battery safety estimation method according to claim 1, characterized in that, The determination of the convective heat transfer coefficient of the battery at different temperatures, based on the current and temperature values ​​in the temperature database and using the battery's electrochemical thermal model, includes: The least squares method is used to fit the current and temperature data in the temperature database; Based on the fitted current and temperature data, the pre-selected convective heat transfer coefficient is determined using the electrochemical thermal model of the battery. Based on the second preset deviation threshold, the pre-selected convective heat transfer coefficient that meets the deviation requirements is determined; When the number of preselected convective heat transfer coefficients that meet the deviation requirements reaches a preset number, the maximum and minimum values ​​of the preselected convective heat transfer coefficients that meet the deviation requirements are removed, and the average value of the remaining preselected convective heat transfer coefficients that meet the deviation requirements is calculated. The average value is used as the convective heat transfer coefficient.

4. The battery safety estimation method according to claim 1, characterized in that, Determining the battery's safety level based on the estimated temperature and the actual temperature includes: The estimated temperature is corrected based on a temperature correction factor, which is used to correct the deviation of the estimated temperature. Determine whether the actual temperature is greater than or equal to the corrected estimated temperature; If the value is greater than the specified value, it is determined that the battery poses a safety risk, and a preset battery protection strategy is executed. If the temperature is less than or equal to the specified value, the battery temperature is considered normal.

5. The battery safety estimation method according to claim 4, characterized in that, Also includes: The method for obtaining the temperature correction coefficient; The acquisition method includes: The temperature of the battery is acquired when the battery is in the low-voltage power-on phase; The corresponding convective heat transfer coefficient is determined based on the temperature of the battery; Based on the convective heat transfer coefficient and the heat generation rate model of the battery, the estimated temperature of the battery is determined; The ratio of the estimated temperature to the temperature of the battery is used as the temperature correction factor. When the battery is in the high-voltage power-on stage and / or charging stage, and the temperature of the battery is determined to be normal, the temperature correction coefficient is updated based on the ratio of the estimated temperature to the actual temperature, and used to correct the estimated temperature at the next time point after that.

6. A battery safety estimation system based on the battery safety estimation method according to any one of claims 1-5, characterized in that, include: The system comprises a first temperature acquisition module, a coefficient determination module, a temperature prediction module, a second temperature acquisition module, and a safety factor determination module; among which... The first temperature acquisition module is used to acquire the current temperature of the battery; The coefficient determination module is connected to the first temperature acquisition module and is used to retrieve the corresponding convective heat transfer coefficient from the set of convective heat transfer coefficients of the battery based on the current temperature. The temperature prediction module is connected to the coefficient determination module and is used to predict the temperature of the battery at the next moment based on the convective heat transfer coefficient and the heat generation rate model of the battery, and use it as the predicted temperature. The second temperature acquisition module is used to acquire the actual temperature of the battery at the next moment; The safety determination module is connected to the temperature estimation module and the second temperature acquisition module, respectively, and is used to determine the safety of the battery based on the estimated temperature and the actual temperature.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the battery safety estimation method as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the battery safety estimation method as described in any one of claims 1 to 5.

9. A vehicle, comprising a vehicle body and a battery, characterized in that, Also includes: The battery safety prediction system as described in claim 6, or the battery safety prediction method as described in any one of claims 1 to 5, is used to predict the safety level. Or the electronic device as described in claim 7; Or the readable storage medium as described in claim 8.

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