Thermal safety capability assessment method and device, equipment and storage medium

Abstract

The invention discloses a thermal safety capability evaluation method, device and equipment and a storage medium, and relates to the field of battery test evaluation. The method is used for evaluating a to-be-tested target, and comprises the following steps: determining first thermal safety capability information of the to-be-tested target before aging; determining second thermal safety capability information after the to-be-tested target is aged; and based on the first thermal safety capability information and the second thermal safety capability information, evaluating the thermal safety capability of the to-be-tested target under the corresponding aging condition. According to the method, the influence of aging of the to-be-tested target in the application process on the thermal safety capability can be fully considered, the thermal safety capability information change before and after aging is integrated, and the thermal safety capability of the to-be-tested target under the corresponding aging working condition is quantitatively evaluated, so that the thermal safety capability of the to-be-tested target can be more reasonably evaluated.

Description

Technical Field

[0001] The present application relates to the technical field of battery testing and evaluation, and specifically to a thermal safety capability evaluation method, device, equipment and storage medium. Background Art

[0002] With the frequent occurrence of lithium battery safety accidents in recent years, how to evaluate the safety of lithium batteries has been a hot topic in the industry. In the research on lithium battery safety, it was found that the battery temperature can reflect the thermal state of the battery, and the temperature is essentially the result of the thermal characteristics of the battery. Therefore, the thermal characteristics of the battery, that is, the heat generation and heat transfer characteristics under different states, are an important representation of the battery's thermal safety capabilities.

[0003] In the related art, the thermal safety capability of battery cells is mainly evaluated through ARC (Accelerated Rate Calorimetry), which is used to obtain the temperature parameters of battery cells and evaluate the thermal safety capability of battery cells by performing ARC tests on battery cells. However, this method cannot evaluate the thermal safety capability of battery cells throughout their entire life cycle, and the evaluation method needs to be improved urgently. Summary of the invention

[0004] Embodiments of the present application provide a thermal safety capability assessment method, apparatus, device, and storage medium to improve the thermal safety capability assessment method.

[0005] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0006] In a first aspect, a thermal safety capability assessment method is provided for assessing a target to be measured, the method comprising:

[0007] Determining first thermal safety capability information of the target to be measured before aging;

[0008] Determining second thermal safety capability information of the target to be measured after aging;

[0009] Based on the first thermal safety capability information and the second thermal safety capability information, the thermal safety capability of the target to be measured under the corresponding aging condition is evaluated.

[0010] In some embodiments, the first thermal safety capability information includes first temperature information, and the second thermal safety capability information includes second temperature information; and the method for evaluating the thermal safety capability of the target under the corresponding aging condition includes:

[0011] Based on the first temperature information, the second temperature information and the parameter change threshold, an evaluation score of the target to be measured is determined to evaluate the thermal safety capability of the target to be measured under the corresponding aging condition.

[0012] In some embodiments, the first temperature information includes a plurality of first temperature parameters, and the second temperature information includes a plurality of second temperature parameters; and the method for determining the evaluation score of the target to be measured includes:

[0013] Determine a score for each of the first temperature parameters based on each of the first temperature parameters, a second temperature parameter corresponding to each of the first temperature parameters, and a parameter change threshold corresponding to each of the first temperature parameters;

[0014] An evaluation score of the target to be measured is determined based on the scores of all the first temperature parameters.

[0015] In some embodiments, determining the evaluation score of the target to be measured based on the scores of all the first temperature parameters includes:

[0016] The sum of the scores of all the first temperature parameters is determined as the evaluation score of the target to be measured.

[0017] In some embodiments, the target to be measured includes a plurality of samples to be measured, and the method for determining the parameter change threshold corresponding to each of the first temperature parameters includes:

[0018] For any of the first temperature parameters, determining a temperature difference between the first temperature parameter and the corresponding second temperature parameter of each of the samples to be tested;

[0019] determining a maximum value from among all said temperature differences;

[0020] The maximum value is determined as a parameter change threshold corresponding to the first temperature parameter.

[0021] In some embodiments, the method for determining the first thermal safety capability information of the target to be measured before aging includes:

[0022] Determining first thermal safety capability information of the target to be tested before aging based on adiabatic accelerated calorimetry test results of each of the target to be tested;

[0023] The method for determining the second thermal safety capability information of the target to be measured after aging includes:

[0024] Determine a paired sample corresponding to each of the samples to be tested, wherein the paired sample is from the same production batch as the sample to be tested and is in the same volume group;

[0025] Performing an aging test on each of the paired samples based on the corresponding aging conditions;

[0026] Based on the adiabatic accelerated calorimetry test results of each of the paired samples after aging, second thermal safety capability information of the target to be tested after aging is determined.

[0027] In some embodiments, before determining the maximum value from all the temperature difference values, the method further comprises:

[0028] Determine, from all the paired samples, a target sample whose adiabatic accelerated calorimetry test result after aging exceeds a preset condition;

[0029] The sample to be tested corresponding to the target sample is removed.

[0030] In some embodiments, the plurality of first temperature parameters include a first self-exothermic start temperature, a first thermal runaway start temperature, and a first thermal runaway maximum temperature, and the plurality of second temperature parameters include a second self-exothermic start temperature, a second thermal runaway start temperature, and a second thermal runaway maximum temperature.

[0031] In some embodiments, the method for determining the aging condition comprises:

[0032] Based on the charge and discharge data and temperature data of the target to be measured throughout its life cycle, a fast charge condition and a slow charge condition are constructed, wherein the charge and discharge data include a ratio of fast charge to slow charge;

[0033] Constructing a cycle condition based on the ratio of the fast charge to the slow charge, the fast charge condition and the slow charge condition;

[0034] Based on the cycle conditions and the target number of cycles, the aging conditions are determined.

[0035] In some embodiments, the charge and discharge data further includes fast charge current, slow charge current and average daily power consumption, and the temperature data includes the annual average temperature of the application environment of the target to be measured; based on the charge and discharge data and temperature data of the target to be measured throughout its life cycle, fast charge conditions and slow charge conditions are constructed, including:

[0036] Constructing the fast charging condition based on the fast charging current, the annual average temperature and the daily average power consumption;

[0037] The slow charging condition is constructed based on the slow charging current, the annual average temperature and the daily average power consumption.

[0038] In some embodiments, based on the fast charging current, the annual average temperature and the daily average power consumption, constructing the fast charging condition includes:

[0039] Charging the target to be tested based on the fast charging current until full charge is achieved;

[0040] Controlling the target to be measured to stand still for a preset time at the annual average temperature;

[0041] Discharging the target to be measured based on a preset discharge rate and the average daily power consumption to determine the remaining power of the target to be measured;

[0042] If the remaining power is greater than zero, the target to be measured is controlled to stand still for the preset time period at the annual average temperature, and the target to be measured is continuously discharged based on the preset discharge rate and the average daily power consumption until the remaining power is equal to zero.

[0043] In a second aspect, a thermal safety capability evaluation device is provided for evaluating a target to be tested, the device comprising:

[0044] A first determination module, used to determine first thermal safety capability information of the target to be measured before aging;

[0045] A second determination module, used to determine second thermal safety capability information of the target to be measured after aging;

[0046] A capability evaluation module is used to evaluate the thermal safety capability of the target to be tested under corresponding aging conditions based on the first thermal safety capability information and the second thermal safety capability information.

[0047] According to a third aspect, an electronic device is provided, the electronic device comprising:

[0048] at least one processor; and a memory communicatively coupled to the at least one processor;

[0049] In which, the memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the thermal safety capability assessment method as described in any one of the first aspects, or so that the processor can configure the thermal safety capability assessment device as described in the second aspect.

[0050] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, wherein the computer instructions are used to enable a processor to implement the thermal safety capability assessment method as described in any one of the first aspects when executed, or the computer instructions are used to enable a processor to configure the thermal safety capability assessment device as described in the second aspect.

[0051] A thermal safety capability evaluation method of the present application is used to evaluate a target to be tested, the method comprising: determining first thermal safety capability information of the target to be tested before aging; determining second thermal safety capability information of the target to be tested after aging; based on the first thermal safety capability information and the second thermal safety capability information, evaluating the thermal safety capability of the target to be tested under corresponding aging conditions. The thermal safety capability evaluation method provided by the present application can fully consider the impact of aging during the application process of the target to be tested on the thermal safety capability, comprehensively consider the changes in thermal safety capability information before and after aging, and quantitatively evaluate the thermal safety capability of the target to be tested under corresponding aging conditions, thereby making a more reasonable evaluation of the thermal safety capability of the target to be tested.

[0052] A thermal safety capability assessment device of the present application can fully consider the impact of aging during the application process of the target to be measured on the thermal safety capability, comprehensively consider the changes in thermal safety capability information before and after aging, and quantitatively assess the thermal safety capability of the target to be measured under corresponding aging conditions, thereby making a more reasonable evaluation of the thermal safety capability of the target to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 The overall process of the thermal safety capability assessment method of the embodiment of the present application;

[0055] Figure 2 This is a schematic diagram of the ARC test process of an embodiment of the present application;

[0056] Figure 3 A schematic diagram of a process for constructing a fast charging condition in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of a process for constructing a slow charging condition in an embodiment of the present application;

[0058] Figure 5 This is a schematic diagram of the structure of a thermal safety capability assessment device according to an embodiment of the present application;

[0059] Figure 6 A schematic diagram of the structure of an electronic device according to an embodiment of the present application;

[0060] Reference numerals:

[0061] 501 - first determination module; 502 - second determination module; 503 - capability evaluation module; 601 - processor; 602 - memory. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0063] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0064] With the frequent occurrence of lithium battery safety accidents in recent years, how to evaluate the safety of lithium batteries has always been a hot topic in the industry. In the research on lithium battery safety, it is found that temperature is always an important physical quantity. Battery temperature can reflect the thermal state of the battery, and temperature is essentially the result of the thermal characteristics of the battery. Therefore, the thermal characteristics of the battery, that is, the heat generation and heat transfer characteristics under different states, are an important representation of the battery's thermal safety capabilities.

[0065] In the related art, the thermal safety capability of battery cells is mainly evaluated through ARC (Accelerated Rate Calorimetry), which is used to obtain the temperature parameters of the battery cells and evaluate the thermal safety capability of the battery cells by performing ARC tests on the battery cells. However, this method does not take into account the aging effect of the battery cells, and thus cannot fully and accurately evaluate the thermal safety capability of the battery cells throughout their life cycle. The evaluation method needs to be improved urgently.

[0066] In view of this, an embodiment of the present application provides a thermal safety capability assessment method for evaluating a target to be measured. By fully considering the impact of aging during the application process of the target to be measured on the thermal safety capability, comprehensively considering the changes in thermal safety capability information before and after aging, the thermal safety capability of the target to be measured under corresponding aging conditions is quantitatively assessed, thereby making a more reasonable evaluation of the thermal safety capability of the target to be measured, and thereby solving at least part of the above-mentioned technical problems.

[0067] Exemplarily, the target to be tested may be an energy storage unit. Further, the target to be tested may be a battery cell or a battery module, wherein the battery module includes a plurality of battery cells, and the number of battery cells is less than or equal to 3. The target to be tested in the embodiment of the present application may be applied to vehicles or other consumer electronic products. The embodiment of the present application has strong universality and expansibility, and does not specifically limit the application scenario.

[0068] In order to more clearly illustrate the embodiments of the present application, unless otherwise specified, the target to be measured is exemplified by taking a battery cell as an example.

[0069] See also Figure 1 , Figure 1 The overall process of the thermal safety capability evaluation method of the embodiment of the present application is as follows. The thermal safety capability evaluation method includes the following steps:

[0070] Step 101: Determine first thermal safety capability information of a target to be tested before aging.

[0071] Specifically, the target to be tested before aging may refer to the target to be tested in a BOL (Beginning of Life) state, and the BOL state refers to the state of the target to be tested when it is just produced or just started to be used.

[0072] In some examples, the first thermal safety capability information may include first temperature information. The first temperature information may include a plurality of first temperature parameters. Exemplarily, the plurality of first temperature parameters include a first self-heating start temperature, a first thermal runaway start temperature, and a first thermal runaway maximum temperature.

[0073] In some examples, the target to be tested may include multiple samples to be tested. The batches and models of the multiple samples to be tested are the same. Taking the target to be tested as a certain battery cell as an example, the multiple samples to be tested may represent multiple battery cells of the same batch and model as the battery cell.

[0074] Exemplarily, the number of samples to be tested may be greater than or equal to 15. In this way, the influence of the production process or aging process of the samples to be tested not being able to ensure complete consistency on the ARC test results can be improved, ensuring that the evaluation results are more reliable.

[0075] In some embodiments, step 101 may be implemented by the following steps:

[0076] Based on the adiabatic accelerated calorimetry test results of each sample to be tested, first thermal safety capability information of the target to be tested before aging is determined.

[0077] Specifically, an ARC test is performed on each sample to be tested, and an ARC test result of each sample to be tested is obtained. The first thermal safety capability information of the target to be tested before aging is characterized by the ARC test results of all samples to be tested.

[0078] Among them, the ARC test provides an approximately adiabatic environment through precise temperature tracking to analyze the exothermic behavior of the sample to be tested, and can measure the thermal characteristics of the internal thermal reaction of the sample to be tested when it is thermally out of control. Parameters need to be set before the test starts, including the starting temperature, heating step, waiting time, and termination temperature. Exemplarily, the starting temperature can be set to 35°C to 40°C, for example, it can be set to any one of 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, or a range of any two values. The heating step can be set to 5°C to 10°C, for example, it can be set to any one of 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, or a range of any two values. The waiting time can be set to 45min (minutes) to 60min (minutes), for example, it can be set to any one of 45min, 46min, 47min, 48min, 49min, 50min, 51min, 52min, 53min, 54min, 55min, 56min, 57min, 58min, 59min, 60min or any two range values. The termination temperature can be set to 300°C. An example of setting the ARC test parameters can be seen in Table 1 below.

[0079] Table 1: Example of ARC test parameters

[0080]

[0081] See also Figure 2 , Figure 2This is a schematic diagram of the ARC test process of an embodiment of the present application. The ARC test modes mainly include heating (Heat) mode, waiting (Wait) mode, search (Seak) mode and adiabatic mode. First, enter the heating mode, start heating the sample to be tested from the starting temperature, and enter the waiting mode after the temperature rises by one step. The purpose of the waiting mode is to make the sample to be tested, the sample container, and the calorimetric chamber reach thermal equilibrium. After the waiting mode ends, it automatically enters the search mode to detect the temperature rise rate. The sensitivity of this type of equipment is generally 0.02℃ / min. If the temperature rise rate is detected to be greater than 0.02℃ / min, it is determined that self-heating has occurred, and enter the adiabatic mode. Continue to record the temperature rise rate and always keep the calorimeter temperature consistent with the temperature of the sample to be tested to prevent heat loss from the sample to be tested. If the temperature rise rate continues to increase and thermal runaway occurs or the temperature reaches the termination temperature, the test is terminated. If the temperature rise rate is ≤0.02℃ / min, ARC will continue to heat in heating steps and run the HWS mode until self-heating occurs or the termination temperature is reached. Among them, the first self-exothermic starting temperature is the temperature of the sample to be tested when the heating rate of the sample to be tested before aging reaches 0.02°C / min, the first thermal runaway starting temperature is the temperature of the sample to be tested when the heating rate of the sample to be tested before aging reaches 1°C / s, and the first thermal runaway maximum temperature is the highest temperature reached by the sample to be tested during the test before aging.

[0082] For example, an example of ARC test results of a certain model of the sample to be tested can be seen in Table 2 below.

[0083] Table 2: Example of ARC test results for the samples under test

[0084]

[0085] Step 102: Determine the second thermal safety capability information of the target to be tested after aging.

[0086] Specifically, the aged target to be tested may refer to a target to be tested in an EOL (End of Life) state, where the EOL state refers to a state when the target to be tested reaches a certain predetermined performance degradation standard during its life cycle.

[0087] In some examples, the second thermal safety capability information may include second temperature information. The second temperature information may include a plurality of second temperature parameters. Exemplarily, the plurality of second temperature parameters include a second self-heating start temperature, a second thermal runaway start temperature, and a second thermal runaway maximum temperature.

[0088] In some embodiments, step 102 may be implemented by:

[0089] Step 1: Determine the paired sample corresponding to each sample to be tested.

[0090] Specifically, paired samples refer to samples that have the same model and production batch as the samples to be tested and are in the same capacity group. The measured capacity and internal resistance of samples in the same capacity group are relatively close. In other words, the measured capacity deviation and internal resistance deviation of the paired samples and the samples to be tested are both within the set range. For example, if the samples to be tested are battery cells, the battery cells are usually paired when they are offline, so the correspondence between the samples to be tested and the paired samples is known when sampling.

[0091] Step 2: Perform aging tests on each paired sample based on the corresponding aging conditions.

[0092] For example, if the sample to be tested is a battery cell and is applied to a vehicle, the operating condition refers to the state of the battery cell in the battery pack during its entire life cycle, mainly including the working state and the storage state. The working state is the process of charging and discharging the battery cell, and the storage state is the process of the vehicle being parked and stationary. Therefore, the operating condition analysis mainly focuses on the charging and discharging conditions and temperature conditions of the battery cell throughout its life cycle.

[0093] In some embodiments, the method for determining the aging condition comprises the following steps:

[0094] The first step is to construct fast charging conditions and slow charging conditions based on the charging and discharging data and temperature data of the target throughout its life cycle. The charging and discharging data includes the ratio of fast charging to slow charging.

[0095] Specifically, the ratio of fast charging to slow charging may be equal to the quotient of the monthly average fast charging times and the monthly average slow charging times. For example, the ratio of fast charging to slow charging = monthly average fast charging times 10 times / monthly average slow charging times 5 times = 2 / 1.

[0096] In some examples, the charge and discharge data also includes fast charge current, slow charge current, and average daily power consumption, and the temperature data includes the annual average temperature of the target application environment to be measured.

[0097] Among them, fast charging current refers to Map (Maximum Allowable Peaking) current, and slow charging current refers to the ratio of 16kW (kilowatt) constant power to charging voltage. The average daily power consumption should be determined in combination with the application scenario of the target to be measured. Taking the application to vehicles as an example, the average daily power consumption = (average annual mileage / standard endurance of the target to be measured / 365) × the power of the target to be measured, for example, the average daily power consumption = (20000km / 500km / 365 days) × 100kWh = 10.96kWh / day, kWh is kilowatt-hour, and km is kilometer. The annual average temperature can be the average temperature of the application environment over a certain period of time, such as the average temperature for three years. The relevant temperature data can be obtained from the meteorological website.

[0098] In some embodiments, fast charging conditions and slow charging conditions can be constructed based on the charging and discharging data and temperature data of the target over its entire life cycle in the following manner:

[0099] Based on the fast charging current, annual average temperature and daily average power consumption, the fast charging condition is constructed. Based on the slow charging current, annual average temperature and daily average power consumption, the slow charging condition is constructed.

[0100] See also Figure 3 , Figure 3 A flow chart for constructing a fast charging condition in an embodiment of the present application. In some examples, the target to be measured can be charged based on the fast charging current until full charge is achieved. The target to be measured is controlled to stand for a preset period of time at the annual average temperature. The target to be measured is discharged based on the preset discharge rate and the average daily power consumption, and the remaining power of the target to be measured is determined. If the remaining power is greater than zero, the target to be measured is controlled to stand for a preset period of time at the annual average temperature, and the target to be measured continues to be discharged based on the preset discharge rate and the average daily power consumption until the remaining power is equal to zero. Among them, the preset duration can be set to 1h (hour). The preset discharge rate can be set to less than or equal to 1C, for example, it can be set to 0.5C or 1C, C represents the current intensity of the target to be measured to be fully discharged in 1 hour, for example, the capacity of a certain battery cell is 100Ah (ampere-hour), and the discharge rate of 0.5C is 50A (ampere).

[0101] See also Figure 4 , Figure 4 A flow chart for constructing a slow charging condition in an embodiment of the present application. In some examples, the target to be measured can be charged based on the slow charging current until full charge is achieved. The target to be measured is controlled to stand for a preset time at the annual average temperature. The target to be measured is discharged based on a preset discharge rate and the average daily power consumption, and the remaining power of the target to be measured is determined. If the remaining power is greater than zero, the target to be measured is controlled to stand for a preset time at the annual average temperature, and the target to be measured is continued to be discharged based on the preset discharge rate and the average daily power consumption until the remaining power is equal to zero.

[0102] Through the above scheme, the construction of fast charging conditions and slow charging conditions can fully consider the temperature and average daily power consumption of the target application environment to be tested, so that the working condition simulation can be more in line with the actual situation and actual products, providing a higher reference value for the evaluation of thermal safety capabilities.

[0103] The second step is to construct a cycle condition based on the ratio of fast charging to slow charging, fast charging conditions and slow charging conditions.

[0104] Specifically, based on the ratio of fast charging to slow charging, the fast charging condition and the slow charging condition are combined to obtain a cycle condition. For example, taking the ratio of fast charging to slow charging as 2, a cycle condition can be composed of two fast charging conditions and one slow charging condition. It is understandable that the embodiments of the present application do not limit the specific number of fast charging conditions and slow charging conditions in the cycle condition, as long as the ratio requirement is met, and the order of the fast charging condition and the slow charging condition in a single cycle condition is not limited.

[0105] The third step is to determine the aging conditions based on the cycle conditions and target cycle number.

[0106] Specifically, the target number of cycles is related to the aging degree to be analyzed. The higher the aging degree, the more target number of cycles can be set. Exemplarily, the target number of cycles can be set to 120. Then, by performing 120 cycles on the sample, the corresponding aging condition can be achieved.

[0107] Step three, based on the adiabatic accelerated calorimetry test results of each paired sample after aging, determine the second thermal safety capability information of the target to be tested after aging.

[0108] Specifically, an ARC test is performed on each aged paired sample, and the ARC test results of each aged paired sample are obtained. The ARC test results of all aged paired samples are used to characterize the second thermal safety capability information of the target after aging. Among them, the second self-exothermic starting temperature is the paired sample temperature when the heating rate of the aged paired sample reaches 0.02°C / min, the second thermal runaway starting temperature is the paired sample temperature when the heating rate of the aged paired sample reaches 1°C / s, and the second thermal runaway maximum temperature is the highest temperature reached by the aged paired sample during the test. The ARC test process refers to the contents of the aforementioned embodiment and will not be repeated here.

[0109] It can be understood that the second self-heating starting temperature corresponds to the first self-heating starting temperature, the second thermal runaway starting temperature corresponds to the first thermal runaway starting temperature, and the second thermal runaway maximum temperature corresponds to the first thermal runaway maximum temperature.

[0110] Through the above scheme, ARC tests are performed on the samples to be tested before aging and the paired samples after aging, and the test results are used to characterize the different states of the target to be tested before and after aging. It not only has strong operability, but also can fully consider the impact of the aging of the target to be tested during its entire life cycle on its thermal safety capability, and comprehensively consider the changes in thermal safety capability before and after aging, which is convenient for the subsequent quantitative evaluation of the thermal safety capability of the target to be tested.

[0111] It is understandable that in other embodiments, ARC tests can also be performed on the paired samples before aging and the test samples after aging, and the test results can be used to characterize the different states of the test target before and after aging. That is, the aging test can be performed on the test samples, and the aging test can also be performed on the paired samples. The embodiments of the present application do not make specific limitations on this.

[0112] Step 103: Based on the first thermal safety capability information and the second thermal safety capability information, the thermal safety capability of the target to be tested under the corresponding aging condition is evaluated.

[0113] In some embodiments, step 103 may be implemented by the following steps:

[0114] Based on the first temperature information, the second temperature information and the parameter change threshold, an evaluation score of the target to be measured is determined to evaluate the thermal safety capability of the target to be measured under the corresponding aging condition.

[0115] Through the above scheme, the evaluation score is calculated by combining the temperature information before and after aging. The thermal safety capability evaluation results of the target to be tested can be obtained more intuitively, efficiently and accurately through the evaluation score, which has good operability and scalability.

[0116] In some examples, the evaluation score of the target to be tested can be determined by the following steps:

[0117] Step 1: Determine a score for each first temperature parameter based on each first temperature parameter, a second temperature parameter corresponding to each first temperature parameter, and a parameter change threshold corresponding to each first temperature parameter.

[0118] Exemplarily, the parameter change threshold corresponding to each first temperature parameter may be determined by the following steps:

[0119] In the first step, for any first temperature parameter, a temperature difference between the first temperature parameter and the corresponding second temperature parameter of each sample to be tested is determined.

[0120] In the second step, the maximum value is determined from all temperature differences.

[0121] In the third step, the maximum value is determined as the parameter change threshold corresponding to the first temperature parameter.

[0122] Taking the multiple first temperature parameters including the first self-heating starting temperature, the first thermal runaway starting temperature and the first thermal runaway maximum temperature, the multiple second temperature parameters including the second self-heating starting temperature, the second thermal runaway starting temperature and the second thermal runaway maximum temperature, and the number of samples to be tested being n as an example, determine the temperature difference ΔT11…ΔT1 between the first self-heating starting temperature and the second self-heating starting temperature of each sample to be tested n and determine the maximum value ΔT1 from all temperature differencesmax =Max(ΔT11,……,ΔT1 n ), which is used as the parameter change threshold corresponding to the first self-heating starting temperature. Determine the temperature difference ΔT21…ΔT2 between the first thermal runaway starting temperature and the second thermal runaway starting temperature of each sample to be tested n and determine the maximum value ΔT2 from all temperature differences max =Max(ΔT21,……,ΔT2 n ), which is used as the parameter change threshold corresponding to the first thermal runaway starting temperature. Determine the temperature difference between the first thermal runaway maximum temperature and the second thermal runaway maximum temperature of each sample to be tested ΔT31…ΔT3 n and determine the maximum value ΔT3 from all temperature differences max =Max(ΔT31,……,ΔT3 n ), which is used as the parameter change threshold corresponding to the first thermal runaway maximum temperature.

[0123] Specifically, after determining the parameter change threshold corresponding to each first temperature parameter, the score of each first temperature parameter may be determined by the following formula:

[0124] Scorei={1-(ΔTi / ΔTi max )}×10;

[0125] Among them, Scorei is the score of the i-th first temperature parameter, ΔTi is the temperature difference between the i-th first temperature parameter and the corresponding second temperature parameter, ΔTi max is the parameter change threshold corresponding to the i-th first temperature parameter. For example, the score Score1 of the first self-heating starting temperature = {1-(ΔT1 / ΔT1 max )}×10, the score of the first thermal runaway starting temperature Score2={1-(ΔT2 / ΔT2 max )}×10, the score of the first thermal runaway maximum temperature Score3={1-(ΔT3 / ΔT3 max )}×10.

[0126] The temperature difference ΔTi between the i-th first temperature parameter and the corresponding second temperature parameter may be based on the temperature differences ΔTi1 . . . ΔTi between the i-th first temperature parameter and the corresponding second temperature parameter of the n samples to be tested. n Determination, for example, can be taken as the average value of the temperature difference between the i-th first temperature parameter of the n samples to be tested and the corresponding second temperature parameter, or can be taken as any value of the temperature difference between the i-th first temperature parameter of the n samples to be tested and the corresponding second temperature parameter, and the embodiment of the present application does not make specific limitations on this.

[0127] Exemplarily, before performing the second step of determining the maximum value from all temperature differences, the method may further include:

[0128] Determine a target sample whose adiabatic accelerated calorimetry test result after aging exceeds a preset condition from all paired samples; and remove the sample to be tested corresponding to the target sample.

[0129] The preset condition may be that the deviation between the adiabatic accelerated calorimetry test result and the average value exceeds a preset threshold. The preset threshold may be set to 2.

[0130] Specifically, according to the adiabatic accelerated calorimetry test results after aging of all paired samples, the average value and standard deviation of the adiabatic accelerated calorimetry test results are determined, and then according to the average value and standard deviation of the adiabatic accelerated calorimetry test results, the deviation of the adiabatic accelerated calorimetry test results of each paired sample after aging from the average value is determined by the following formula:

[0131]

[0132] Where, |Z| is the deviation of the adiabatic accelerated calorimetry test result of the t-th paired sample after aging from the average value, X 测 is the adiabatic accelerated calorimetry test result of the t-th paired sample after aging, is the average value of the adiabatic accelerated calorimetry test results of all paired samples after aging, σ is the standard deviation of the adiabatic accelerated calorimetry test results of all paired samples after aging, t is an integer greater than or equal to 1 and less than or equal to n, and n is the total number of samples to be tested.

[0133] Exemplarily, the adiabatic accelerated calorimetry test results after aging can use the self-heating starting temperature after aging, that is, when the deviation of the second self-heating starting temperature from the average value is greater than or equal to 2, the sample to be tested corresponding to the corresponding paired sample can be removed and does not participate in the calculation of the parameter change threshold and score. In this way, the consistency of the samples to be tested can be screened according to the most influential features, which is more efficient. Alternatively, the adiabatic accelerated calorimetry test results after aging can also use the self-heating starting temperature, the thermal runaway starting temperature and the thermal runaway maximum temperature, that is, when the second self-heating starting temperature, the second thermal runaway starting temperature and the second thermal runaway maximum temperature are all greater than or equal to 2 from the corresponding average value, the sample to be tested corresponding to the corresponding paired sample can be removed and does not participate in the calculation of the parameter change threshold and score. The embodiments of the present application do not specifically limit this.

[0134] Step 2: Determine the evaluation score of the target to be measured based on the scores of all the first temperature parameters.

[0135] Exemplarily, the sum of the scores of all first temperature parameters may be determined as the evaluation score of the target to be measured.

[0136] As another example, a coefficient of difference can be introduced, and the product of the coefficient of difference and the sum of the scores of all first temperature parameters is determined as the evaluation score of the target to be measured. The coefficient of difference is calculated as measured capacity / nominal capacity × 100%, and the nominal capacity is the capacity size marked on the package by the manufacturer according to the product specification. In this way, the differences in material systems, manufacturing processes, etc. between different targets to be measured can be considered more comprehensively, so that the evaluation score can eliminate the differences between different targets to be measured and have better comparability.

[0137] It can be understood that the thermal safety capability assessment method of the embodiment of the present application can fully consider the impact of the aging of the target to be tested during its entire life cycle on its thermal safety capability, comprehensively consider the changes in thermal safety capability before and after aging, and realize the quantitative evaluation of the thermal safety capability of the target to be tested. It also has strong universality and expansibility, and can be used for the development and application of target products to be tested in a wide range, and can also be used for independent analysis and application of a certain product application area. Therefore, the evaluation of the thermal safety capability of the target to be tested is more reasonable.

[0138] Accordingly, the present application also provides a thermal safety capability evaluation device for evaluating a target to be tested. Figure 5 , Figure 5 The thermal safety capability evaluation device provided in the embodiment of the present application comprises a first determination module 501 , a second determination module 502 and a capability evaluation module 503 .

[0139] A first determination module 501 is used to determine first thermal safety capability information of the target to be tested before aging;

[0140] A second determination module 502 is used to determine the second thermal safety capability information of the target to be tested after aging;

[0141] The capability evaluation module 503 is used to evaluate the thermal safety capability of the target to be tested under the corresponding aging condition based on the first thermal safety capability information and the second thermal safety capability information.

[0142] In some embodiments, the first thermal safety capability information includes first temperature information, and the second thermal safety capability information includes second temperature information; the capability evaluation module 503 is specifically used to:

[0143] Based on the first temperature information, the second temperature information and the parameter change threshold, an evaluation score of the target to be measured is determined to evaluate the thermal safety capability of the target to be measured under the corresponding aging condition.

[0144] In some embodiments, the first temperature information includes a plurality of first temperature parameters, and the second temperature information includes a plurality of second temperature parameters; the capability evaluation module 503 is specifically used for:

[0145] Determine a score for each first temperature parameter based on each first temperature parameter, a second temperature parameter corresponding to each first temperature parameter, and a parameter change threshold corresponding to each first temperature parameter;

[0146] Based on the scores of all the first temperature parameters, an evaluation score of the object to be measured is determined.

[0147] In some embodiments, the capability assessment module 503 is specifically used to:

[0148] The sum of the scores of all the first temperature parameters is determined as the evaluation score of the target to be measured.

[0149] In some embodiments, the target to be tested includes multiple samples to be tested, and the capability evaluation module 503 is specifically used to:

[0150] For any first temperature parameter, determining a temperature difference between the first temperature parameter and the corresponding second temperature parameter of each sample to be tested;

[0151] Determine the maximum value from all temperature differences;

[0152] The maximum value is determined as the parameter change threshold corresponding to the first temperature parameter.

[0153] In some embodiments, the first determining module 501 is specifically configured to:

[0154] Determine the first thermal safety capability information of the target to be tested before aging based on the adiabatic accelerated calorimetry test results of each sample to be tested;

[0155] The second determining module 502 is specifically used for:

[0156] Determine the paired samples corresponding to each sample to be tested. The paired samples are from the same production batch as the sample to be tested and are in the same volume group;

[0157] Perform aging tests on each paired sample based on the corresponding aging conditions;

[0158] Based on the adiabatic accelerated calorimetry test results of each paired sample after aging, the second thermal safety capability information of the target to be tested after aging is determined.

[0159] In some embodiments, before determining the maximum value from all temperature differences, the capability evaluation module 503 is further configured to:

[0160] Determine a target sample from among all paired samples whose adiabatic accelerated calorimetry test result after aging exceeds a preset condition;

[0161] Remove the samples to be tested corresponding to the target samples.

[0162] In some embodiments, the plurality of first temperature parameters include a first self-exothermic start temperature, a first thermal runaway start temperature, and a first thermal runaway maximum temperature, and the plurality of second temperature parameters include a second self-exothermic start temperature, a second thermal runaway start temperature, and a second thermal runaway maximum temperature.

[0163] In some embodiments, the capability assessment module 503 is specifically used to:

[0164] Based on the charge and discharge data and temperature data of the target during its entire life cycle, fast charging and slow charging conditions are constructed. The charge and discharge data includes the ratio of fast charging to slow charging.

[0165] Based on the ratio of fast charging to slow charging, fast charging conditions and slow charging conditions, a cycle condition is constructed;

[0166] Determine the aging conditions based on the cycle conditions and target cycle number.

[0167] In some embodiments, the charge and discharge data further includes fast charge current, slow charge current and average daily power consumption, and the temperature data includes the annual average temperature of the target application environment to be measured; the capability evaluation module 503 is specifically used for:

[0168] Construct fast charging conditions based on fast charging current, annual average temperature and daily average power consumption;

[0169] The slow charging condition is constructed based on the slow charging current, annual average temperature and daily average power consumption.

[0170] In some embodiments, the capability assessment module 503 is specifically used to:

[0171] The target to be tested is charged based on the fast charging current until it is fully charged;

[0172] Control the target to be tested to stand still for a preset time at the annual average temperature;

[0173] Discharging the target to be tested based on the preset discharge rate and the average daily power consumption to determine the remaining power of the target to be tested;

[0174] If the remaining power is greater than zero, the target to be tested is controlled to stand still for a preset time at the annual average temperature, and continues to discharge the target to be tested based on the preset discharge rate and the average daily power consumption until the remaining power is equal to zero.

[0175] It can be understood that the thermal safety capability assessment device of the embodiment of the present application can fully consider the impact of aging during the application process of the target to be measured on the thermal safety capability, comprehensively consider the changes in thermal safety capability information before and after aging, and quantitatively assess the thermal safety capability of the target to be measured under corresponding aging conditions, thereby making a more reasonable evaluation of the thermal safety capability of the target to be measured.

[0176] Accordingly, see Figure 6 , Figure 6 Schematic diagram of the structure of an electronic device according to an embodiment of the present application. An electronic device provided in an embodiment of the present application includes at least one processor 601; and a memory 602 connected to the at least one processor 601 for communication. The memory 602 stores a computer program executable by the at least one processor 601, and the computer program is executed by the at least one processor 601 so that the at least one processor 601 can execute the thermal safety capability assessment method according to the embodiment of the present application, or so that the processor 601 can configure the thermal safety capability assessment device according to the embodiment of the present application.

[0177] Accordingly, an embodiment of the present application further provides a computer-readable storage medium, which stores computer instructions, and the computer instructions are used to implement the thermal safety capability assessment method of the embodiment of the present application when executed by a processor.

[0178] The above is a detailed introduction to a thermal safety capability assessment method, device, equipment and storage medium provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thermal safety capability assessment method, characterized in that: For evaluating a target to be measured, the method comprises: Determining first thermal safety capability information of the target to be measured before aging; Determining second thermal safety capability information of the target to be measured after aging; Based on the first thermal safety capability information and the second thermal safety capability information, the thermal safety capability of the target to be measured under the corresponding aging condition is evaluated.

2. The thermal safety capability assessment method according to claim 1, characterized in that: The first thermal safety capability information includes first temperature information, and the second thermal safety capability information includes second temperature information; and the method for evaluating the thermal safety capability of the target to be measured under the corresponding aging condition includes: Based on the first temperature information, the second temperature information and the parameter change threshold, an evaluation score of the target to be measured is determined to evaluate the thermal safety capability of the target to be measured under the corresponding aging condition.

3. The thermal safety capability assessment method according to claim 2, characterized in that: The first temperature information includes a plurality of first temperature parameters, and the second temperature information includes a plurality of second temperature parameters; The method for determining the evaluation score of the target to be measured comprises: Determine a score for each of the first temperature parameters based on each of the first temperature parameters, a second temperature parameter corresponding to each of the first temperature parameters, and a parameter change threshold corresponding to each of the first temperature parameters; An evaluation score of the target to be measured is determined based on the scores of all the first temperature parameters.

4. The thermal safety capability assessment method according to claim 3, characterized in that: The step of determining the evaluation score of the target to be measured based on the scores of all the first temperature parameters includes: The sum of the scores of all the first temperature parameters is determined as the evaluation score of the target to be measured.

5. The thermal safety capability assessment method according to claim 3, characterized in that: The target to be tested includes a plurality of samples to be tested, and the method for determining a parameter change threshold value corresponding to each of the first temperature parameters includes: For any of the first temperature parameters, determining a temperature difference between the first temperature parameter and the corresponding second temperature parameter of each of the samples to be tested; determining a maximum value from among all said temperature differences; The maximum value is determined as a parameter change threshold corresponding to the first temperature parameter.

6. The thermal safety capability assessment method according to claim 5, characterized in that: The method for determining the first thermal safety capability information of the target to be measured before aging includes: Determining first thermal safety capability information of the target to be tested before aging based on adiabatic accelerated calorimetry test results of each of the target to be tested; The method for determining the second thermal safety capability information of the target to be measured after aging includes: Determine a paired sample corresponding to each of the samples to be tested, wherein the paired sample is from the same production batch as the sample to be tested and is in the same volume group; Performing an aging test on each of the paired samples based on the corresponding aging conditions; Based on the adiabatic accelerated calorimetry test results of each of the paired samples after aging, second thermal safety capability information of the target to be tested after aging is determined.

7. The thermal safety capability assessment method according to claim 6, characterized in that: Before determining the maximum value from all the temperature difference values, the method further comprises: Determine, from all the paired samples, a target sample whose adiabatic accelerated calorimetry test result after aging exceeds a preset condition; The sample to be tested corresponding to the target sample is removed.

8. The thermal safety capability assessment method according to any one of claims 3 to 7, characterized in that: The plurality of first temperature parameters include a first self-exothermic start temperature, a first thermal runaway start temperature and a first thermal runaway maximum temperature, and the plurality of second temperature parameters include a second self-exothermic start temperature, a second thermal runaway start temperature and a second thermal runaway maximum temperature.

9. The thermal safety capability assessment method according to claim 1, characterized in that: The method for determining the aging condition includes: Based on the charge and discharge data and temperature data of the target to be measured throughout its life cycle, a fast charge condition and a slow charge condition are constructed, wherein the charge and discharge data include a ratio of fast charge to slow charge; Constructing a cycle condition based on the ratio of the fast charge to the slow charge, the fast charge condition and the slow charge condition; Based on the cycle conditions and the target number of cycles, the aging conditions are determined.

10. The thermal safety capability assessment method according to claim 9, characterized in that: The charging and discharging data also include fast charging current, slow charging current and daily average power consumption, and the temperature data include the annual average temperature of the application environment of the target to be measured; Based on the charging and discharging data and temperature data of the target during its entire life cycle, fast charging conditions and slow charging conditions are constructed, including: Constructing the fast charging condition based on the fast charging current, the annual average temperature and the daily average power consumption; The slow charging condition is constructed based on the slow charging current, the annual average temperature and the daily average power consumption.

11. The thermal safety capability assessment method according to claim 10, characterized in that: Based on the fast charging current, the annual average temperature and the daily average power consumption, the fast charging condition is constructed, including: Charging the target to be tested based on the fast charging current until full charge is achieved; Controlling the target to be measured to stand still for a preset time at the annual average temperature; Discharging the target to be measured based on a preset discharge rate and the average daily power consumption to determine the remaining power of the target to be measured; If the remaining power is greater than zero, the target to be measured is controlled to stand still for the preset time period at the annual average temperature, and the target to be measured is continuously discharged based on the preset discharge rate and the average daily power consumption until the remaining power is equal to zero.

12. A thermal safety capability assessment device, characterized in that: For evaluating a target to be measured, the device comprises: A first determination module, used to determine first thermal safety capability information of the target to be measured before aging; A second determination module, used to determine second thermal safety capability information of the target to be measured after aging; A capability evaluation module is used to evaluate the thermal safety capability of the target to be tested under corresponding aging conditions based on the first thermal safety capability information and the second thermal safety capability information.

13. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively coupled to the at least one processor; In which, the memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the thermal safety capability assessment method as described in any one of claims 1 to 11, or so that the processor can configure the thermal safety capability assessment device as described in claim 12.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, which are used to enable a processor to implement the thermal safety capability assessment method as described in any one of claims 1 to 11 when executed, or the computer instructions are used to enable a processor to configure the thermal safety capability assessment device as described in claim 12.

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