Thermal diffusion testing method, testing equipment and computer readable storage medium

Abstract

The embodiment of the invention provides a thermal diffusion testing method, testing equipment and a computer readable storage medium. The method comprises the following steps: triggering a first battery monomer in a test battery to generate thermal runaway, the electric quantity of the test battery meeting a first preset condition, and the temperature of the test battery meeting a second preset condition; acquiring battery parameter information of a second battery monomer in the test battery, wherein the second battery monomer and the first battery monomer meet a first position relationship; and according to the battery parameter information of the second battery cell, determining whether thermal diffusion occurs in the test battery. According to the method, the test equipment and the computer readable storage medium provided by the embodiment of the invention, the reliability and the accuracy of the thermal diffusion test are improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of battery testing, and in particular, to a method for thermal diffusion testing, a testing device, and a computer-readable storage medium. Background Art

[0002] The number of electric vehicle fire incidents in the market is increasing continuously, and the safety of electric vehicles has attracted much attention. Most of the electric vehicle fire incidents are caused by thermal diffusion of the battery. Therefore, during the development process of the battery, there is an urgent need for a thermal diffusion test at the battery level to expose product defects and continuously improve the battery design and manufacturing process to improve product quality. Summary of the Invention

[0003] The embodiments of the present application provide a method for thermal diffusion testing, a testing device, and a computer-readable storage medium, which are beneficial to improving the reliability and accuracy of thermal diffusion testing.

[0004] In a first aspect, a method for thermal diffusion testing is provided, including: triggering a first battery cell in a test battery to undergo thermal runaway, where the power of the test battery meets a first preset condition and the temperature of the test battery meets a second preset condition; obtaining battery parameter information of a second battery cell in the test battery, where the second battery cell and the first battery cell satisfy a first positional relationship; and determining whether thermal diffusion occurs in the test battery according to the battery parameter information of the second battery cell.

[0005] In the embodiments of the present application, by triggering a first battery cell in a test battery to undergo thermal runaway and determining whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell that satisfies a first positional relationship with the first battery cell in the test battery, since the power of the test battery is strictly controlled to meet the first preset condition and the temperature of the test battery meets the second preset condition before triggering the first battery cell to undergo thermal runaway, it is beneficial to ensure the accuracy and reliability of the test results.

[0006] In a possible implementation manner, the temperature of the test battery meeting the second preset condition includes: the temperature of the test battery is not less than 40°C.

[0007] In this embodiment, setting the temperature of the test battery to be not less than 40°C is beneficial to covering the most severe scenarios experienced in the later application stage, so that the test results can be more effective and the risk of thermal diffusion can be reduced.

[0008] In a possible implementation manner, the power of the test battery meeting the first preset condition includes: the state of charge of the test battery reaches 100%.

[0009] In this embodiment, before performing a thermal diffusion test on a test battery, the SOC of the test battery is charged to 100%, which is beneficial to making the test battery in the condition most likely to undergo thermal diffusion, thereby making the result of the thermal diffusion test more reliable.

[0010] In a possible implementation, the second battery cell and the first battery cell satisfy a first positional relationship, including: the second battery cell is adjacent to the first battery cell.

[0011] In this embodiment, when it is monitored that a certain battery cell in the test battery undergoes thermal runaway, the battery parameter information of the battery cell adjacent to the battery cell that has undergone thermal runaway is monitored in real time, which is beneficial to detecting thermal diffusion of the test battery earlier, thereby reducing the irreversible impact brought by thermal diffusion.

[0012] In a possible implementation, the first battery cell is close to the central position inside the test battery, and / or the first battery cell is surrounded by other battery cells inside the test battery.

[0013] In this embodiment, the first battery cell that is close to the central position inside the test battery and / or surrounded by other battery cells is selected as the object to trigger thermal runaway, making the test battery more likely to undergo thermal diffusion, thereby improving the reliability of the thermal diffusion test.

[0014] In a possible implementation, before or after triggering thermal runaway of the first battery cell in the test battery, the method further includes: turning on the cooling system of the test battery.

[0015] In this embodiment, before or after triggering thermal runaway of the first battery cell in the test battery, turning on the cooling system of the test battery is beneficial to taking into account the ability of the test battery to handle thermal runaway in the thermal diffusion test, enabling some batteries that have undergone thermal runaway but can avoid thermal diffusion by turning on the cooling system to still enter the market, while reducing the probability of the battery undergoing thermal diffusion and improving the yield of the battery.

[0016] In a possible implementation, the cooling system is a water cooling system, and the method further includes: controlling the water cooling system to perform a water circulation for a first preset duration, and the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper limit value of the state of charge at which the test battery operates, the lower limit value of the state of charge at which the test battery operates, and the rated energy of the water pump.

[0017] In this embodiment, when the thermal runaway of the battery under test is triggered, usually the water-cooling system has no high voltage and cannot perform refrigeration and cooling. Only the heat can be carried away by the water circulation. Therefore, by controlling the duration of the water circulation of the water-cooling system, it is beneficial to more accurately verify the ability of the test battery to handle thermal runaway in the thermal diffusion test.

[0018] In a possible implementation, the first preset duration is determined based on the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, C is the rated capacity of the low-voltage power supply provided by the test battery, V is the rated voltage of the low-voltage power supply provided by the test battery, SOC1 is the upper limit value of the state of charge of the test battery during operation, SOC2 is the lower limit value of the state of charge of the test battery during operation, W2 is the rated energy of the water pump, and T is the first preset duration.

[0019] In a possible implementation, determining whether thermal diffusion occurs in the test battery according to the battery parameter information of the second battery cell includes: determining that thermal diffusion has occurred in the test battery when it is monitored that the battery parameter information satisfies at least one of the following conditions: the voltage of the second battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the second battery cell reaches a temperature threshold, and the temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration.

[0020] In this embodiment, when at least one of the following conditions is met: the voltage of the second battery cell drops to a preset ratio of the initial voltage, the temperature of the second battery cell reaches the temperature threshold, and the temperature rise rate of the second battery cell is greater than or equal to the first threshold and lasts for more than the second preset duration, it is determined that thermal diffusion has occurred in the test battery, and the performance of the test battery can be evaluated more accurately.

[0021] In a possible implementation, the method further includes: heating the test battery to meet the second preset condition before triggering thermal runaway in the first battery cell of the test battery.

[0022] In this embodiment, after heating the test battery to meet the second preset condition and then performing the thermal diffusion test on the test battery, it is beneficial to cover the most severe scenarios experienced in the later application stage, so that the test results can be more effective and the risk of thermal diffusion can be reduced.

[0023] In a possible implementation, the method further includes: controlling the heating device to be removed from the test platform when it is determined that thermal diffusion has occurred in the test battery, and the heating device is used to heat the test battery to meet the second preset condition.

[0024] In this embodiment, in the case where it is determined that thermal diffusion has occurred in the test battery, moving the temperature-raising device out of the test platform can reduce the impact of thermal diffusion on the temperature-raising device.

[0025] In a possible implementation manner, triggering thermal runaway of the first battery cell in the test battery includes: turning on a heating device in surface contact with the first battery cell so that the first battery cell satisfies at least one of the following conditions: the voltage of the first battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the first battery cell reaches a temperature threshold, and the temperature rise rate of the first battery cell is not less than a first threshold and lasts for more than a second preset duration.

[0026] In this embodiment, the method of triggering thermal runaway by contact can reduce the probability of damaging the external structure or sealing structure of the battery cell or the test battery, so that the simulated thermal runaway behavior can be as real as possible.

[0027] In a possible implementation manner, the test battery is a battery installed with a customized frame.

[0028] In this embodiment, by installing a customized frame for the test battery, the environment of the thermal diffusion test can be made more real and the test results can be more accurate.

[0029] In a second aspect, a test device is provided for performing a thermal diffusion test on a test battery. The test device includes a processor; the processor is configured to trigger thermal runaway of the first battery cell in the test battery, the power of the test battery satisfies a first preset condition, and the temperature of the test battery satisfies a second preset condition; the processor is further configured to obtain battery parameter information of the second battery cell in the test battery, and the second battery cell and the first battery cell satisfy a first positional relationship; the processor is further configured to determine whether thermal diffusion has occurred in the test battery according to the battery parameter information of the second battery cell.

[0030] In a possible implementation manner, the temperature of the test battery satisfies the second preset condition, including: the temperature of the test battery is not less than 40 °C.

[0031] In a possible implementation manner, the power of the test battery satisfies the first preset condition, including: the state of charge of the test battery reaches 100%.

[0032] In a possible implementation manner, the second battery cell and the first battery cell satisfy the first positional relationship, including: the second battery cell is adjacent to the first battery cell.

[0033] In a possible implementation manner, the first battery cell is close to the central position in the test battery, and / or, the first battery cell is surrounded by other battery cells in the test battery.

[0034] In a possible implementation, the processor is further configured to: turn on the cooling system of the test battery before or after triggering thermal runaway of the first battery cell in the test system.

[0035] In a possible implementation, the cooling system is a water-cooling system, and the processor is further configured to: control the water-cooling system to perform a water circulation for a first preset duration, where the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper limit value of the state of charge at which the test battery operates, the lower limit value of the state of charge at which the test battery operates, and the rated energy of the water pump.

[0036] In a possible implementation, the first preset duration is determined based on the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, C is the rated capacity of the low-voltage power supply provided by the test battery, V is the rated voltage of the low-voltage power supply provided by the test battery, SOC1 is the upper limit value of the state of charge at which the test battery operates, SOC2 is the lower limit value of the state of charge at which the test battery operates, W2 is the rated energy of the water pump, and T is the first preset duration.

[0037] In a possible implementation, the processor is specifically configured to: determine that thermal diffusion has occurred in the test battery when it monitors that the battery parameter information meets at least one of the following conditions: the voltage of the second battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the second battery cell reaches a temperature threshold, and the temperature rise rate of the second battery cell is not less than a first threshold and lasts for more than a second preset duration.

[0038] In a possible implementation, the processor is specifically configured to: control the heating device to heat the test battery to meet a second preset condition before triggering thermal runaway of the first battery cell in the test battery.

[0039] In a possible implementation, the processor is further configured to: control the heating device to be removed from the test platform when it determines that thermal diffusion has occurred in the test battery.

[0040] In a possible implementation, the processor is specifically configured to: turn on the heating device in surface contact with the first battery cell so that the first battery cell meets at least one of the following conditions: the voltage of the first battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the first battery cell reaches a temperature threshold, and the temperature rise rate of the first battery cell is not less than a first threshold and lasts for more than a second preset duration.

[0041] In one possible implementation, the test battery is a battery installed with a customized frame.

[0042] In a third aspect, a chip is provided, including a processor for calling and running a computer program from a memory, so that a device installed with the chip executes the method in the first aspect and any possible implementation of the first aspect.

[0043] In a fourth aspect, a computer program is provided, which enables a computer to execute the method in the first aspect and any possible implementation of the first aspect.

[0044] In a fifth aspect, a computer-readable storage medium is provided for storing a computer program, which enables a computer to execute the method in the first aspect and any possible implementation of the first aspect.

[0045] In a sixth aspect, a computer program product is provided, including computer program instructions, which enable a computer to execute the method in the first aspect and any possible implementation of the first aspect. Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0047] Figure 1 A schematic exploded view of the test battery according to the embodiment of the present application is shown.

[0048] Figure 2 A first schematic block diagram of the method for thermal diffusion test according to the embodiment of the present application is shown.

[0049] Figure 3 A second schematic block diagram of the method for thermal diffusion test according to the embodiment of the present application is shown.

[0050] Figure 4 A third schematic block diagram of the method for thermal diffusion test according to the embodiment of the present application is shown.

[0051] Figure 5 A fourth schematic block diagram of the method for thermal diffusion test according to the embodiment of the present application is shown.

[0052] Figure 6 A fifth schematic block diagram of the method for thermal diffusion test according to the embodiment of the present application is shown.

[0053] Figure 7The figure shows a schematic diagram of the installation positions of the heating device and the temperature sensor in the method of triggering thermal runaway by heating according to an embodiment of the present application.

[0054] Figure 8 The figure shows a schematic diagram of the positional relationship between the acupuncture point and the temperature sensor in the method of triggering thermal runaway by acupuncture according to an embodiment of the present application.

[0055] Figure 9 The figure shows a schematic flowchart of the method for thermal diffusion testing according to an embodiment of the present application.

[0056] Figure 10 The figure shows a schematic block diagram of the test equipment according to an embodiment of the present application. Detailed implementation manners

[0057] The following further describes in detail the implementation manners of the present application in conjunction with the drawings and embodiments. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principle of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0058] In the description of the present application, it should be noted that unless otherwise specified, the meaning of "a plurality of" is two or more; in addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0059] Currently, from the perspective of the development of the market situation, power batteries are more and more widely used. Power batteries are not only applied to energy storage systems such as hydropower, thermal power, wind power, and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, and electric trucks. Even more, they can be applied to multiple fields such as the military field and aerospace. With the continuous expansion of the application fields of power batteries, the market demand is also constantly increasing.

[0060] Due to reasons such as manufacturing defects or improper use of the battery, the battery will undergo thermal runaway in extreme cases, resulting in an increase in the internal temperature of the battery. In severe cases, it will even cause a thermal runaway chain reaction, that is, thermal diffusion or thermal spread, leading to battery fire and explosion. Since thermal runaway cannot be absolutely avoided, only the probability of occurrence can be reduced or the harm caused after thermal runaway can be mitigated. Therefore, during the battery development process, thermal diffusion testing is usually carried out on the battery to expose product defects, and the battery design and manufacturing process are continuously improved to reduce the harm caused after thermal runaway and improve the battery quality. The results of current thermal diffusion testing often cannot accurately evaluate the safety of the battery.

[0061] In view of this, an embodiment of the present application provides a method for thermal diffusion testing. By triggering thermal runaway in the first battery cell of the test battery and determining whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell in the test battery that satisfies the first positional relationship with the first battery cell, since the power of the test battery is strictly controlled to meet the first preset condition and the temperature of the test battery meets the second preset condition before triggering thermal runaway in the first battery cell, it is beneficial to ensure the accuracy and reliability of the test results.

[0062] Figure 1 FIG. 4 shows a schematic structural diagram of a test battery 10 according to an embodiment of the present application. As Figure 1 shown, the test battery 10 may include a plurality of battery cells 20. The test battery 10 further includes a box body 30, the interior of the box body 30 is a hollow structure, and the plurality of battery cells 20 are accommodated in the box body 30. Figure 1 FIG. 5 shows a possible implementation manner of the box body 30 according to an embodiment of the present application. As Figure 1 shown, the box body 30 may include two parts, which are respectively referred to as a first part 31 and a second part 32 here, and the first part 31 and the second part 32 are buckled together. The shapes of the first part 31 and the second part 32 may be determined according to the shape of the combined plurality of battery cells 20.

[0063] Figure 2 FIG. 6 shows a schematic block diagram of a method 100 for thermal diffusion testing according to an embodiment of the present application. Optionally, the method 100 may be executed by a test device. For example, the test device may include a host computer. As Figure 2 shown, the method 100 includes the following parts or all of the content.

[0064] S110, trigger thermal runaway in the first battery cell of the test battery, the power of the test battery meets the first preset condition, and the temperature of the test battery meets the second preset condition.

[0065] S120, obtain the battery parameter information of the second battery cell in the test battery, and the second battery cell satisfies the first positional relationship with the first battery cell.

[0066] S130, determine whether thermal diffusion occurs in the test battery according to the battery parameter information of the second battery cell.

[0067] The test battery in the embodiment of the present application may be as Figure 1 shown, that is, the test battery may include a plurality of battery cells, and the plurality of battery cells at least include a first battery cell and a second battery cell.

[0068] The thermal diffusion test is used to evaluate the potential safety risks of thermal diffusion that may occur in a test battery due to thermal runaway of a single battery cell. In the embodiments of the present application, when performing a thermal diffusion test on a test battery, the thermal runaway of the first battery cell in the test battery can be triggered first, then the battery parameter information of the second battery cell in the test battery can be obtained, and finally, based on the battery parameter information of the second battery cell, it can be determined whether thermal diffusion has occurred in the test battery.

[0069] In some embodiments, it can be determined whether thermal diffusion has occurred in the test battery by judging whether the second battery cell has also experienced thermal runaway. For example, it can be determined whether the second battery cell has experienced thermal runaway by judging whether the temperature of the second battery cell has reached a certain value, thereby determining whether thermal diffusion has occurred in the test battery.

[0070] In other embodiments, it can also be determined whether thermal diffusion has occurred in the test battery by judging whether the pressure inside the test battery has reached a certain value. In other embodiments, it can also be determined whether thermal diffusion has occurred in the test battery by judging whether the smoke concentration inside the test battery has reached a certain value. The embodiments of the present application do not specifically limit how to determine whether thermal diffusion has occurred in the test battery.

[0071] In the embodiments of the present application, before triggering the thermal runaway of the first battery cell in the test battery, the power of the test battery is set to meet the first preset condition, and the temperature of the test battery is set to meet the second preset condition. Among them, the first preset condition and the second preset condition can be preset according to different actual working conditions of the battery to cover the actual worst-case scenario as much as possible. In addition, before performing a thermal diffusion test on the test battery, the positional relationship between the first battery cell and the second battery cell also needs to be preset. For example, there is a preset number of battery cells spaced between the first battery cell and the second battery cell. Once it is determined that the first battery cell has experienced thermal runaway, the second battery cell can be found according to the preset positional relationship, and the battery parameter information of the second battery cell can be obtained. In this case, before performing a thermal diffusion test on the test battery, each battery cell in the test battery may need to be modified. For example, each battery cell is internally equipped with a heating device for triggering thermal runaway, and each battery cell is provided with a sensor for obtaining battery parameter information. The airtightness after modification should meet the design requirements.

[0072] In some other embodiments, the first battery cell and the second battery cell can also be directly specified before the thermal diffusion test of the test battery. Once it is determined that the first battery cell has a thermal runaway, the battery parameter information of the second battery cell can be directly obtained. In this case, before the thermal diffusion test of the test battery, it may only be necessary to install a heating device for triggering thermal runaway in the first battery cell, and sensors for obtaining battery parameter information in the first battery cell and the second battery cell, without modifying other battery cells in the test battery.

[0073] The battery parameter information in the embodiments of the present application refers to the parameter information related to the battery cell. More specifically, the battery parameter information refers to the parameter information that can be used to judge whether a thermal runaway occurs. For example, the battery parameter information can be voltage information, temperature information, or pressure information, etc. In some embodiments, the battery parameter information can be obtained by sensors. For example, the voltage information can be obtained by a voltage sensor, the temperature information can be obtained by a temperature sensor, and the pressure information can be obtained by a pressure sensor. Further, the sensor can transmit the obtained battery parameter information to the host computer for the host computer to judge whether a certain battery cell in the test battery has a thermal runaway or whether the test battery has a thermal diffusion.

[0074] In the embodiments of the present application, by triggering a thermal runaway of the first battery cell in the test battery and determining whether the test battery has a thermal diffusion based on the battery parameter information of the second battery cell that satisfies the first positional relationship with the first battery cell in the test battery, since the power of the test battery is strictly controlled to meet the first preset condition and the temperature of the test battery meets the second preset condition before triggering the thermal runaway of the first battery cell, it is beneficial to ensure the accuracy and reliability of the test results.

[0075] In some embodiments, the temperature of the test battery meets the second preset condition, including: the temperature of the test battery is not less than 40 °C.

[0076] Generally, for the above-mentioned electric vehicles, the higher the ambient temperature, the more likely it is to cause thermal diffusion of the battery. For example, in the hot summer, the batteries on the vehicle are more likely to undergo thermal diffusion. During the development of the battery, if the thermal diffusion test of the battery to be installed on the vehicle is carried out at room temperature, the test results may be inaccurate. For example, if the result of the thermal diffusion test of the test battery at room temperature shows that thermal diffusion is not likely to occur, but the vehicle equipped with this test battery is in a high-temperature scenario for a long time, such as the exposure scenario in the hot summer, then this test battery may still undergo thermal diffusion, which may lead to the failure of the thermal diffusion test during the battery development process. Therefore, in this case, performing the thermal diffusion test on the test battery at a high temperature, for example, setting the temperature of the test battery to be not less than 40°C, helps to cover the most severe scenarios experienced in the later application stage, thereby making the test results more effective and reducing the risk of thermal diffusion.

[0077] Optionally, the temperature of the test battery can be between 40°C and 50°C. For example, the temperature of the test battery is 40°C, 45°C or 50°C.

[0078] In some other embodiments, when the temperature of the test battery meets the second preset condition, it further includes: the temperature of the test battery reaches 55°C or reaches the maximum operating temperature specified by the manufacturer. For example, if the maximum operating temperature specified by the manufacturer is 60°C, then before the thermal diffusion test, the temperature of the test battery can be set to 60°C first.

[0079] In the actual vehicle scenario, the vehicle records vehicle data, such as the temperature data of the battery. However, this data does not distinguish the actual vehicle usage scenarios. Therefore, by deeply analyzing and inferring this vehicle data, the second preset condition can be finally defined.

[0080] The definition logic of the second preset condition will be described in detail below with specific embodiments.

[0081] Data source: Select more than 200,000 passenger cars, covering more than 15 models. The chemical systems of the batteries used include NCM ternary lithium materials and lithium iron phosphate LFP materials. These 200,000 passenger cars are mainly used in Jilin, Beijing, Shanghai, Guangzhou and other places.

[0082] Data Screening: The main usage scenarios of the vehicle are as follows: 1. Transportation / Storage; 2. Vehicle Assembly; 3. Driving (High Load); 4. Driving (Low Load); 5. Charging (High Load); 6. Charging (Low Load); 7. Parking (Connected to the Network); 8. Parking (Disconnected from the Network); 9. After-sales Maintenance; 10. Special Scenarios (Washing / Changing Batteries, etc.). Considering that load, state of charge (SOC), and battery temperature are characteristic parameters of severe scenarios, through screening, the typical severe scenarios of battery thermal runaway are identified as high-temperature and high-load charging (fast charging), high-temperature and high-load driving (discharging), and parked with network disconnected (exposed to the sun). Among them, high load means that there is a large current passing through. For example, current / capacity > 1 is regarded as high load. In addition, since there is only temperature data inside the battery in the whole vehicle and the ambient temperature of the battery is lacking, the afternoon in summer (11:00 - 18:00) will be regarded as high temperature with reference to the air temperature. Specifically, the temperature data recorded by the above 2 million passenger cars in the afternoon between June 2022 and August 2022 in the above three typical severe scenarios can be selected. In addition, during the parking process of the vehicle, the battery is in a dormant state and the temperature data inside the battery cannot be detected. The time interval between the first frame time when waking up and the last frame time when parking can be used as the static time. When the static time > 3h, it is considered that thermal equilibrium has been reached and the condition of being exposed to the sun is met.

[0083] Data Processing: Since there are 3 typical severe scenarios in actual use, in order to obtain the weighted result, it is necessary to compare the data duration of the three scenarios to obtain a ratio, and finally obtain the weighted value of the temperature, as shown in Table 1.

[0084] Table 1

[0085]

[0086] Definition of the Second Preset Condition: As can be seen from Table 1, 3σ = 47.3°C, Mean value = 37.6°C. Considering that the capacity ranges of different batteries are different, after rounding, the temperature is between 40°C and 50°C, that is, the temperature of the test battery meets the second preset condition, which means that the temperature of the test battery is at least not less than 40°C.

[0087] In another embodiment of the present application, the thermal diffusion test of the test battery can also be carried out at room temperature, that is, before the thermal diffusion test, the temperature of the test battery is at room temperature. Room temperature can usually be defined as a temperature below 0°C and less than 40°C. For example, before the thermal diffusion test, the temperature of the test battery is 10°C, 15°C, 20°C or 25°C, etc.

[0088] In some embodiments, the test battery's charge meets the first preset condition, including: the SOC of the test battery reaches 100%, in other words, the test battery needs to be charged to full charge.

[0089] Specifically, the test battery can be charged according to GB38031. That is, first discharge the test battery to the discharge cut-off voltage specified in the manufacturer's technical conditions with a current not less than I3 as specified by the manufacturer, and then set it aside for 1 h (or the set-aside time not greater than 1 h provided by the manufacturer). Then charge it according to the charging method provided by the manufacturer. If the manufacturer does not provide a charging method, the appropriate charging method shall be determined through negotiation between the testing agency and the manufacturer, or charge it according to the following method: constant-current charge with a current not less than I3 as specified by the manufacturer until the test battery reaches the charge cut-off voltage specified in the manufacturer's technical conditions, then switch to constant-voltage charging, and stop charging when the charging current drops to 0.05I1. After charging, set it aside for 1 h (or the 1 h set-aside time provided by the manufacturer), where I1 is the rated current and I3 is 1 / 3 of the rated current.

[0090] In this embodiment, before the thermal diffusion test of the test battery, charging the SOC of the test battery to 100% is beneficial to making the test battery in the condition most likely to have thermal diffusion, so that the result of the thermal diffusion test is more reliable.

[0091] In other embodiments, the thermal diffusion test can also be carried out when the SOC of the test battery is at other values. For example, the thermal diffusion test of the test battery can be carried out when the SOC of the test battery reaches 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95%. Since in actual use of the vehicle, the probability of being in the most severe scenario is small. For example, the battery is fully charged in a high-temperature environment for a long time. Therefore, the SOC of the test battery can be appropriately reduced during the test, which is beneficial to improving the yield of the battery.

[0092] In some embodiments, the second battery cell and the first battery cell satisfy a first positional relationship, including: the second battery cell is adjacent to the first battery cell.

[0093] Generally, when a thermal runaway occurs in a certain battery cell in the battery, if the thermal runaway problem cannot be handled in time, it is very likely to spread to other battery cells in the battery, thereby causing thermal runaway in other battery cells. Especially the battery cell adjacent to the thermally runaway battery cell is the earliest and most likely to be implicated. Therefore, in the embodiment of the present application, when it is monitored that a thermal runaway occurs in a certain battery cell in the test battery, the battery parameter information of the battery cell adjacent to the battery cell with thermal runaway is monitored in real time, which is beneficial to detecting the thermal diffusion of the test battery earlier, so that the irreversible influence brought by the thermal diffusion can be reduced.

[0094] In some other embodiments, the second battery cell may not be adjacent to the first battery cell either. That is, in the case where thermal runaway occurs in the first battery cell in the test battery, the battery parameter information of the second battery cell that is separated from the first battery cell by a preset number of battery cells may also be monitored, and it may be determined whether thermal diffusion occurs in the test battery.

[0095] In some embodiments, the first battery cell is close to the central position within the test battery, and / or the first battery cell is surrounded by other battery cells within the test battery.

[0096] For example, Figure 1 if the test battery 10 in includes 25 battery cells arranged along the first direction X, then the first battery cell may be the 13th battery cell arranged in sequence from one end to the other end along the first direction X, that is, the first battery cell is the Figure 1 battery cell 21 in. Again, for example, the first battery cell may also be the Figure 1 battery cell 22 in, which is surrounded by the battery cell 23 and the battery cell 24.

[0097] In this embodiment, selecting the first battery cell that is close to the central position within the test battery and / or surrounded by other battery cells as the object to trigger thermal runaway makes it more likely for the test battery to undergo thermal diffusion, thereby improving the reliability of the thermal diffusion test.

[0098] In some other embodiments, the first battery cell may also be selected in the following manner: 1. Select the battery cell at the position where heat dissipation and exhaust are blocked: usually the central position of the test battery; 2. Select the battery cell at the position with a relatively high risk of high-voltage arcing: usually close to the high-voltage port position; 3. Select the battery cell at the position where the water cooling system is relatively weak: that is, the weak position of the water cooling pipeline.

[0099] In some embodiments, as shown in Figure 3 , before or after triggering thermal runaway in the first battery cell in the test battery, the method 100 further includes: S140, turning on the cooling system of the test battery.

[0100] Optionally, the cooling system may be a liquid cooling system, an air cooling system, or a direct cooling system. Among them, the air cooling system may use air as the heat exchange medium to cool the battery. The liquid cooling system uses liquid as the heat exchange medium to cool the battery. The direct cooling system uses refrigerant as the heat exchange medium to absorb heat during the gas-liquid phase change process to cool the battery.

[0101] In some embodiments, it may be to turn on the cooling system of the test battery before triggering thermal runaway in the first battery cell in the test battery, so that the probability of thermal runaway or the probability of thermal diffusion can be reduced by using the cooling system during the entire thermal diffusion test process.

[0102] In some other embodiments, after the thermal runaway of the first battery cell in the test battery is triggered, the cooling system of the test battery can be turned on, so that the cooling system can be used to reduce the impact caused by the thermal runaway. For example, the probability of thermal diffusion can be reduced.

[0103] In this embodiment, turning on the cooling system of the test battery before or after the thermal runaway of the first battery cell in the test battery is triggered is beneficial to taking into account the ability of the test battery to handle thermal runaway in the thermal diffusion test, so that some batteries that have experienced thermal runaway but can avoid thermal diffusion by turning on the cooling system can still enter the market, improving the yield of the battery while reducing the probability of thermal diffusion of the battery.

[0104] In some embodiments, as Figure 3 shown, the cooling system is a water cooling system, and the method 100 further includes: S150, controlling the water cooling system to perform water circulation for a first preset duration, where the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper SOC limit value at which the test battery operates, the lower SOC limit value at which the test battery operates, and the rated energy of the water pump.

[0105] During the actual use of the vehicle, when a thermal runaway is triggered, the battery will report the fault to the vehicle and request to disconnect the high voltage. When the water cooling system has no high voltage, the compressor cannot be started, that is, there is no cooling power. At this time, the cooling can only be carried out by the circulating water pump. Since refrigeration and temperature reduction cannot be carried out at this time, only heat can be taken away by circulation. Therefore, it is necessary to refer to the vehicle strategy and consider the most severe working conditions.

[0106] Similarly, during the thermal diffusion test, it can be first determined whether the water circulation of the water cooling system can be awakened. If the water circulation of the water cooling system cannot be awakened, the thermal diffusion test is carried out under the most severe working conditions, that is, the test battery is set to the water circulation non-triggerable mode. Once the thermal runaway of the first battery cell in the test battery is triggered, the water cooling system does not refrigerate and does not circulate. For the test battery undergoing the thermal diffusion test under this working condition, the probability of thermal diffusion after entering the market is relatively low. If the water circulation of the water cooling system can be awakened, the test battery is set to the water circulation triggerable mode. Once the thermal runaway of the first battery cell in the test battery is triggered, the water cooling system only circulates water and does not refrigerate, and the water cooling flow rate can refer to the vehicle strategy.

[0107] In some embodiments, determining whether the water circulation of the water cooling system can be triggered may be performed after triggering thermal runaway of the first battery cell. Once it is determined that the water circulation of the water cooling system can be triggered, the water cooling system is controlled to perform water circulation. Once it is determined that the water circulation of the water cooling system cannot be triggered, the water cooling system is controlled not to perform water circulation.

[0108] In other embodiments, determining whether the water circulation of the water cooling system can be triggered may also be performed before triggering thermal runaway of the first battery cell. Once it is determined that the water circulation of the water cooling system can be triggered, it is subsequently defaulted to execute in the mode where the water circulation of the water cooling system can be triggered during the thermal diffusion test. If it is determined that the water circulation of the water cooling system cannot be triggered, it is subsequently defaulted to execute in the mode where the water circulation of the water cooling system cannot be triggered during the thermal diffusion process.

[0109] Optionally, the first preset duration can also be preset in combination with the actual working conditions. In some embodiments, the first preset duration is less than 1 h. For example, the first preset duration can be 30 min.

[0110] In some embodiments, the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper SOC limit value at which the test battery operates, the lower SOC limit value at which the test battery operates, and the rated energy of the water pump.

[0111] The so-called low-voltage power supply provided by the test battery refers to the DC power supply provided by the test battery, which is usually used to provide a stable DC power supply for electronic devices, sensors, controllers, etc. Among them, the rated energy of the low-voltage power supply provided by the test battery refers to the maximum electric energy or energy that the DC power supply provided by the test battery can provide. The rated capacity of the low-voltage power supply provided by the test battery refers to the output power of the DC power supply provided by the test battery under the rated voltage and rated current. Similarly, the rated voltage of the low-voltage power supply provided by the test battery refers to the rated voltage of the DC power supply provided by the test battery. For example, the rated voltage is 220V. The rated energy of the water pump usually refers to the maximum flow rate and range that the water pump can provide under the specified conditions.

[0112] The upper SOC limit value at which the test battery operates depends on the performance and life of the test battery. For example, generally, the upper SOC limit value at which the battery operates should be between 80% and 90%. The lower SOC limit value at which the test battery operates depends on the type and performance of the test battery. For example, for lead-acid batteries, its lower SOC limit value is usually 10%, while for lithium-ion batteries, its lower SOC limit value is usually 0%.

[0113] In this embodiment, when triggering a thermal runaway of the battery under test, usually the water cooling system has no high voltage and cannot perform refrigeration and cooling. It can only rely on the water cycle to take away heat. Therefore, by controlling the duration of the water cycle of the water cooling system, it is beneficial to more accurately verify the ability of the test battery to handle thermal runaway in the thermal diffusion test.

[0114] In some embodiments, the first preset duration is determined based on the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, in wh; C is the rated capacity of the low-voltage power supply provided by the test battery, in Ah; V is the rated voltage of the low-voltage power supply provided by the test battery, in V; SOC1 is the upper limit value of the SOC at which the test battery operates, in %; SOC2 is the lower limit value of the SOC at which the test battery operates, in %; W2 is the rated energy of the water pump, in wh; T is the first preset duration, that is, the duration of the water cycle when only powered by the low-voltage power supply, in min.

[0115] In some embodiments, as Figure 4 shown, S130, that is, determining whether the test battery has thermal diffusion according to the battery parameter information of the second battery cell, includes: S131, when it is monitored that the battery parameter information of the second battery cell satisfies at least one of the following conditions, determining that the test battery has thermal diffusion: the voltage of the second battery cell drops to a preset ratio of the initial voltage, the temperature of the second battery cell reaches the temperature threshold, and the temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration.

[0116] That is to say, a voltage sensor and a temperature sensor can be set in the second battery cell. After triggering a thermal runaway of the first battery cell, the voltage sensor and / or temperature sensor in the second battery cell can monitor the voltage and / or temperature of the second battery cell in real time, and can synchronously upload the voltage data and / or temperature data to the host computer. The host computer further determines whether the voltage data and / or temperature data meet the above several conditions. Once it is determined that the voltage data and / or temperature data of the second battery cell meet one of the above conditions, it can be determined that the second battery cell is affected by the first battery cell, and further it can be determined that the test battery has thermal diffusion.

[0117] In some embodiments, it is only necessary to judge the battery parameter information of the second battery cell according to one of the above conditions. For example, it can only be judged whether the voltage of the second battery cell drops to a preset ratio of the initial voltage. For another example, it can only be judged whether the temperature of the second battery cell reaches the temperature threshold. For another example, it can only be judged whether the temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration.

[0118] It should be understood that if a certain above condition is not met, in order to ensure the reliability of thermal diffusion, several of the above conditions can be combined for judgment. If at least two of the above conditions are not met, it can be considered that the second battery cell has not experienced thermal runaway. For example, when the voltage of the second battery cell drops to a preset ratio of the initial voltage, and the temperature of the second battery cell reaches the temperature threshold, it can be considered that the second battery cell has experienced thermal runaway. Another example, when the temperature of the second battery cell reaches the temperature threshold, and the temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration, it can be considered that the second battery cell has experienced thermal runaway.

[0119] In some embodiments, determining whether a test battery has experienced thermal diffusion based on the battery parameter information of the second battery cell includes: determining that the test battery has experienced thermal diffusion when the battery parameter information of the second battery cell meets at least one of the following conditions: the voltage of the second battery cell drops by more than 25% of the initial voltage, the temperature of the second battery cell reaches the maximum operating temperature specified by the manufacturer, and the temperature rise rate of the second battery cell is not less than 1 °C / s and lasts for more than 3 s.

[0120] It should be understood that the above preset ratio, temperature threshold, first threshold, and second preset duration can be adjusted according to actual situations.

[0121] In this embodiment, when at least one of the following conditions is met: the voltage of the second battery cell drops to the preset ratio of the initial voltage, the temperature of the second battery cell reaches the temperature threshold, and the temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration, it is determined that the test battery has experienced thermal diffusion, which can more accurately evaluate the performance of the test battery.

[0122] In some embodiments, as Figure 5 shown, method 100 further includes: S160, before triggering thermal runaway of the first battery cell in the test battery, heating the test battery to meet the second preset condition.

[0123] Optionally, before performing the thermal diffusion test, the test battery can be preheated using a heating device. For example, the heating device is an incubator. The test battery can be placed in the incubator, and the incubator temperature can be set. For example, the incubator temperature can be set to be greater than or equal to 55 °C, and the incubator is turned on to heat the test battery. When the temperature sensor in the test battery monitors that the temperature of the test battery is 55 °C, the heating of the test battery by the incubator is stopped.

[0124] If the test environment does not have an incubator, the test battery can also be heated to meet the second preset condition in the form of water-cooled heating.

[0125] In this embodiment, after heating the test battery to meet the second preset condition, performing a thermal diffusion test on the test battery is beneficial to cover the most severe scenarios experienced in the later application stage, so that the test results can be more effective and the risk of thermal diffusion can be reduced.

[0126] In some embodiments, as Figure 5 shown, method 100 further includes: S170, when it is determined that thermal diffusion has occurred in the test battery, controlling the heating device to move out of the test platform, where the heating device is used to heat the test battery to meet the second preset condition.

[0127] Optionally, moving the heating device out of the test platform can be manually operated or controlled by a host computer. For example, the host computer can communicate with the heating device. Once the host computer determines that thermal diffusion has occurred in the test battery, it can interact with the heating device to control the heating device to move out of the test platform.

[0128] Optionally, the heating device is a heating device with a slide rail.

[0129] In this embodiment, when it is determined that thermal diffusion has occurred in the test battery, moving the heating device out of the test platform can reduce the impact of thermal diffusion on the heating device.

[0130] In some embodiments, as Figure 6 shown, S110, that is, triggering thermal runaway of the first battery cell in the test battery, includes: S111, turning on the heating device in contact with the surface of the first battery cell so that the first battery cell meets at least one of the following conditions: the voltage of the first battery cell drops to a preset ratio of the initial voltage, the temperature of the first battery cell reaches the temperature threshold, and the temperature rise rate of the first battery cell is not less than the first threshold and lasts for more than the second preset duration.

[0131] Before performing the thermal diffusion test on the test battery, the test battery can be modified first, that is, at least install a heating device in the test battery so that the heating device is in contact with the surface of the first battery cell.

[0132] In some embodiments, a planar or rod-shaped heating device can be used, and its surface should be covered with a ceramic, metal, or insulating layer. For a block-shaped heating device with the same size as the battery cell, one of the battery cells can be replaced with this heating device, which is in direct contact with the surface of the first battery cell. For a thin-film heating device, it should always be attached to the surface of the first battery cell; the heating area of the heating device should not be larger than the surface area of the battery cell, the heating surface of the heating device is in direct contact with the surface of the first battery cell, the position of the heating device should correspond to the position of the temperature sensor, the power requirements of the heating device are shown in Table 2, and when thermal runaway occurs or the temperature monitored by the temperature sensor reaches 300 °C, the heating stops.

[0133] Table 2

[0134] Electric energy E (Wh) of the first battery cell Maximum power of the heating device (W) E＜100 30～300 100≤E＜400 300～1000 400≤E＜800 300～2000 E≥800 ＞600

[0135] In some other embodiments, a heating device can also be arranged inside the first battery cell, that is, the heating device is arranged inside the housing of the first battery cell. For example, the heating device can be connected to the inner wall of the housing of the first battery cell. For another example, the heating device can also be connected to the electrode assembly inside the first battery cell, such as clamping the heating device between two electrode assemblies.

[0136] Not only a heating device needs to be arranged inside the first battery cell, but also a sensor needs to be arranged to monitor whether thermal runaway occurs in the first battery cell, such as a temperature sensor. The corresponding positions of the temperature sensor and the heating device can be as Figure 7 shown, that is, the temperature sensor is arranged on the opposite side of the heating device. Optionally, the sampling interval of the temperature data should be less than 1 s, and the accuracy requirement is ±2 °C.

[0137] In this embodiment, the method of triggering thermal runaway by heating can reduce the probability of damaging the external structure or sealing structure of the battery cell or the test battery, so that the simulated thermal runaway behavior can be as real as possible.

[0138] Optionally, for the heating film, its size can be 30 * 30 mm, its resistance value can be approximately 50 Ω. Specifically, the heating film can be led out of the test battery, and an external voltage greater than 42 V is connected. When thermal runaway occurs in the first battery cell in the test battery, the heating stops.

[0139] In some other embodiments, a pinprick-triggered thermal runaway method can also be adopted. Specifically, the pinprick material is steel, the diameter of the pin is directly greater than 3 mm to 8 mm, the tip shape of the pin is conical and the angle is 20° to 60°, the pinprick speed is 0.1 mm / s to 10 mm / s, and the position and direction that can trigger thermal runaway of the first battery cell are selected. For example, the direction perpendicular to the electrode plate of the first battery cell. When triggering by pinprick, the position of the temperature sensor should be as close as possible to the pinprick point, as Figure 8 shown.

[0140] In some embodiments, triggering thermal runaway of the first battery cell in the test battery includes: turning on a heating device in contact with the surface of the first battery cell so that the first battery cell satisfies at least one of the following conditions: the voltage of the first battery cell drops by more than 25% of the initial voltage, the temperature of the first battery cell reaches the maximum operating temperature specified by the manufacturer, and the temperature rise rate of the first battery cell is not less than 1 °C / s and lasts for more than 3 s.

[0141] It should be understood that the method for judging whether the first battery cell has a thermal runaway can refer to the method for judging whether the second battery cell has a thermal runaway. For the sake of brevity, it will not be elaborated here.

[0142] In some embodiments, the test battery is a battery installed with a customized vehicle frame.

[0143] Since most of the installation positions of the battery in the whole vehicle are in the chassis position, at this time the battery is in a non-free state. Once a thermal runaway occurs, it will affect the exhaust path. Therefore, during the thermal diffusion test, the state of the test battery in the whole vehicle should be restored as much as possible. The vehicle frame should be customized and installed according to the gap between the test battery and the vehicle frame and the shielding situation of the pressure relief mechanism, so that the environment of the thermal diffusion test can be more real and the test results can be more accurate.

[0144] After the thermal diffusion test results, the test battery can be left standing for 2 h, or the external surface temperature of the test battery can be lowered to below 45 °C. In addition, after the thermal diffusion test of the test battery, it is also necessary to detect whether the test battery has phenomena such as fire and explosion.

[0145] In some embodiments, before the thermal diffusion test of the test battery, the test battery needs to be in the following working modes: 1. Power on the power supply line, activate the wake-up signal, activate the CAN communication and other initialization functions, and disable other functions; or, 2. All protection devices that affect the functions of the test battery and are related to the test results should be in a normal operating state, and all relevant main contactors for discharging should be closed.

[0146] Before conducting a thermal diffusion test on a test battery, the following pre-treatments need to be performed on the test battery. Specifically, first, an insulation test is conducted on the test battery. Among them, the measurement voltage used should be 1.5 times the nominal voltage of the test battery or a voltage of 500 (d.c.), taking the higher value of the two. The applied voltage should be long enough to obtain a stable reading, and the recommended measurement duration is 30 s. Secondly, a communication check is conducted on the test battery, that is, the power supply line is powered on, the wake-up signal is activated, the CAN communication and other initialization functions are activated, and it is checked that there are no sharp changes in the sampling of voltage, temperature, etc., and no fault signals are reported.

[0147] Figure 9 FIG. shows a schematic flowchart of a method 200 for thermal diffusion testing according to an embodiment of the present application. Optionally, as Figure 9 shown, the method 200 may include some or all of the following.

[0148] S201, pre-treat the test battery. For example, it includes performing an insulation test on the test battery. For another example, a communication check is conducted on the test battery. For another example, the test battery is charged to 100% SOC.

[0149] S202, modify the test battery. For example, a heating device is arranged inside the test battery. For another example, the test battery is installed on a customized vehicle frame.

[0150] S203, place the test battery in an incubator and heat the test battery to meet the second preset condition. For example, heat the test battery to 55 °C.

[0151] S204, select a triggering method to trigger a thermal runaway of the first battery cell in the test battery. For example, the heating device in contact with the surface of the first battery cell can be turned on and heated until the first battery cell undergoes thermal runaway.

[0152] S205, trigger the water circulation of the water cooling system of the test battery.

[0153] S206, do not trigger the water circulation of the water cooling system of the test battery.

[0154] S207. If the water circulation of the water cooling system is triggered, the circulation duration can be calculated according to the formula. For example, the circulation duration can be calculated according to the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, in wh; C is the rated capacity of the low-voltage power supply provided by the test battery, in Ah; V is the rated voltage of the low-voltage power supply provided by the test battery, in V; SOC1 is the upper limit value of the SOC at which the test battery operates, in %; SOC2 is the lower limit value of the SOC at which the test battery operates, in %; W2 is the rated energy of the water pump, in wh; T is the first preset duration, that is, the duration of the water circulation when only powered by the low-voltage power supply, in min.

[0155] S208. If the water circulation of the water cooling system cannot be triggered, the water cooling does not circulate.

[0156] S209. Further, it can be determined whether it spreads to the second battery cell. For example, similar to determining that the first battery cell has a thermal runaway, the battery parameter information of the second battery cell monitored can be used to determine whether the second battery cell has a thermal runaway. Once the second battery cell has a thermal runaway, it can be considered that the thermal runaway of the first battery cell spreads to the second battery cell.

[0157] S210. If it is determined that it spreads to the second battery cell, the incubator is removed from the test platform.

[0158] S211. If it is determined that it does not spread to the second battery cell, the constant temperature heating can be continued until the test ends.

[0159] The above has described in detail the thermal diffusion test method of the embodiments of the present application. Next, Figure 10 the test equipment of the embodiments of the present application will be described in detail. The technical features described in the method embodiments are applicable to the following device embodiments.

[0160] Figure 10 Fig. shows a schematic block diagram of the test equipment 300 of the embodiments of the present application. As Figure 10 shown, the test equipment 300 includes the following parts or all of the content.

[0161] The processor 310 is used to trigger a thermal runaway of the first battery cell in the test battery, the power of the test battery meets the first preset condition, and the temperature of the test battery meets the second preset condition; the processor 310 is further used to obtain the battery parameter information of the second battery cell in the test battery, and the second battery cell and the first battery cell satisfy the first positional relationship; the processor 310 is further used to determine whether thermal diffusion occurs in the test battery according to the battery parameter information of the second battery cell.

[0162] Optionally, in the embodiments of the present application, the temperature of the test battery satisfies the second preset condition, including: the temperature of the test battery is not less than 40 °C.

[0163] Optionally, in the embodiments of the present application, the power of the test battery satisfies the first preset condition, including: the state of charge of the test battery reaches 100%.

[0164] Optionally, in the embodiments of the present application, the second battery cell and the first battery cell satisfy the first positional relationship, including: the second battery cell is adjacent to the first battery cell.

[0165] Optionally, in the embodiments of the present application, the first battery cell is close to the central position in the test battery, and / or, the first battery cell is surrounded by other battery cells in the test battery.

[0166] Optionally, in the embodiments of the present application, the processor 310 is further configured to: turn on the cooling system of the test battery before or after triggering a thermal runaway of the first battery cell in the test battery.

[0167] Optionally, in the embodiments of the present application, the cooling system is a water cooling system, and the processor 310 is further configured to: control the water cooling system to perform a water circulation for a first preset duration, and the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper SOC limit value at which the test battery operates, the lower SOC limit value at which the test battery operates, and the rated energy of the water pump.

[0168] Optionally, in the embodiments of the present application, the first preset duration is determined based on the following formula:

[0169] W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, C is the rated capacity of the low-voltage power supply provided by the test battery, V is the rated voltage of the low-voltage power supply provided by the test battery, SOC1 is the upper SOC limit value at which the test battery operates, SOC2 is the lower SOC limit value at which the test battery operates, W2 is the rated energy of the water pump, and T is the first preset duration.

[0170] Optionally, in the embodiments of the present application, the processor 310 is specifically configured to: determine that a thermal diffusion has occurred in the test battery when it is monitored that the battery parameter information satisfies at least one of the following conditions: the voltage of the second battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the second battery cell reaches a temperature threshold, and the temperature rise rate of the second battery cell is not less than a first threshold and lasts for more than a second preset duration.

[0171] Optionally, in the embodiments of the present application, the processor 310 is specifically configured to: before triggering thermal runaway of the first battery cell in the test battery, control the heating device to heat the test battery to meet the second preset condition.

[0172] Optionally, in the embodiments of the present application, the processor 310 is further configured to: in the case of determining that thermal diffusion has occurred in the test battery, control the heating device to be removed from the test platform.

[0173] Optionally, in the embodiments of the present application, the processor 310 is specifically configured to: turn on the heating device in contact with the surface of the first battery cell, so that the first battery cell meets at least one of the following conditions: the voltage of the first battery cell drops to exceed a preset ratio of the initial voltage, the temperature of the first battery cell reaches the temperature threshold, and the temperature rise rate of the first battery cell is not less than the first threshold and lasts for more than the second preset duration.

[0174] Optionally, in the embodiments of the present application, the test battery is a battery equipped with a customized frame.

[0175] Optionally, as Figure 10 shown, the test device further includes a memory 320, wherein the memory 320 is used to store instructions, and the processor 310 is used to read the instructions and execute the methods of the various embodiments of the present application based on the instructions.

[0176] Among them, the memory 320 can be a separate device independent of the processor 310, or can be integrated in the processor 310.

[0177] Optionally, the test device 300 may further include a transceiver 330, and the processor 310 can control the transceiver 330 to communicate with other devices. Specifically, information or data can be sent to other devices, or information or data sent by other devices can be received.

[0178] It should be understood that each module or unit in the test device 300 can implement the corresponding processes in the thermal diffusion test method provided by the embodiments of the present application. For the sake of brevity, details are not described herein again.

[0179] The embodiments of the present application further provide a chip, including a processor, which is used to call and run a computer program from a memory, so that a device installed with the chip executes the methods of the various embodiments of the present application described above.

[0180] It should be understood that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. In the implementation process, the steps of the above method embodiments can be completed by the integrated logic circuit in the hardware of the processor or instructions in software form. The above processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being executed and completed by the hardware decoding processor, or executed and completed by a combination of the hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method.

[0181] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0182] The embodiments of the present application also provide a computer storage medium for storing a computer program, and the computer program is used to execute the methods of the various embodiments of the present application described above.

[0183] Optionally, the computer-readable storage medium can be applied to the test device in the embodiments of the present application, and the computer program causes the computer to execute the corresponding processes implemented by the test device in the various methods of the embodiments of the present application. For the sake of brevity, it will not be described in detail here.

[0184] The embodiments of the present application also provide a computer program product, including computer program instructions.

[0185] Optionally, the computer program product can be applied to the test device in the embodiments of the present application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the test device in the various methods of the embodiments of the present application. For the sake of brevity, it will not be described in detail here.

[0186] The embodiments of the present application also provide a computer program.

[0187] Optionally, the computer program can be applied to the test device in the embodiments of the present application. When the computer program runs on a computer, it causes the computer to execute the corresponding processes implemented by the test device in the various methods of the embodiments of the present application. For the sake of brevity, it will not be elaborated here.

[0188] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for thermal diffusion testing, characterized in that, Including: Triggering thermal runaway of the first battery cell in the test battery, where the power of the test battery meets a first preset condition and the temperature of the test battery meets a second preset condition; Obtaining battery parameter information of a second battery cell in the test battery, where the second battery cell and the first battery cell satisfy a first positional relationship; Determining whether thermal diffusion has occurred in the test battery based on the battery parameter information of the second battery cell.

2. The method according to claim 1, wherein The temperature of the test battery meeting the second preset condition includes: the temperature of the test battery is not less than 40°C.

3. The method according to claim 1 or 2, characterized in that, The power of the test battery meeting the first preset condition includes: the state of charge of the test battery reaches 100%.

4. The method according to any one of claims 1 to 3, characterized in that, The second battery cell and the first battery cell satisfying the first positional relationship includes: the second battery cell is adjacent to the first battery cell.

5. The method according to any one of claims 1 to 4, characterized in that, The first battery cell is close to the central position inside the test battery, and / or, the first battery cell is surrounded by other battery cells inside the test battery.

6. The method according to any one of claims 1 to 5, characterized in that, Before or after triggering thermal runaway of the first battery cell in the test battery, the method further includes: turning on the cooling system of the test battery.

7. The method according to claim 6, wherein The cooling system is a water cooling system, and the method further includes: Controlling the water cooling system to perform a water circulation for a first preset duration; Wherein, the first preset duration is determined based on at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper limit value of the state of charge at which the test battery operates, the lower limit value of the state of charge at which the test battery operates, and the rated energy of the water pump.

8. The method according to claim 7, wherein The first preset duration is determined based on the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, C is the rated capacity of the low-voltage power supply provided by the test battery, V is the rated voltage of the low-voltage power supply provided by the test battery, SOC1 is the upper limit value of the state of charge at which the test battery operates, SOC2 is the lower limit value of the state of charge at which the test battery operates, W2 is the rated energy of the water pump, and T is the first preset duration.

9. The method according to any one of claims 1 to 8, characterized in that, The determining whether thermal diffusion has occurred in the test battery based on the battery parameter information of the second battery cell includes: Determining that thermal diffusion has occurred in the test battery when it is monitored that the battery parameter information meets at least one of the following conditions: The voltage of the second battery cell drops to exceed a preset ratio of the initial voltage, The temperature of the second battery cell reaches a temperature threshold, and The temperature rise rate of the second battery cell is not less than a first threshold and lasts for more than a second preset duration.

10. The method according to any one of claims 1 to 9, characterized in that, The method further includes: Before triggering thermal runaway of the first battery cell in the test battery, heating the test battery to meet the second preset condition.

11. The method according to claim 10, wherein The method further includes: When it is determined that thermal diffusion has occurred in the test battery, control the heating device to move out of the test platform. The heating device is used to heat the test battery to meet the second preset condition.

12. The method according to any one of claims 1 to 11, characterized in that, Triggering a thermal runaway in the first battery cell of the test battery includes: Turning on the heating device in surface contact with the first battery cell so that the first battery cell meets at least one of the following conditions: The voltage of the first battery cell drops to exceed a preset ratio of the initial voltage, The temperature of the first battery cell reaches the temperature threshold, and The temperature rise rate of the first battery cell is not less than the first threshold and lasts for more than the second preset duration.

13. The method according to any one of claims 1 to 12, characterized in that, The test battery is a battery equipped with a customized frame.

14. A testing device, characterized in that, For performing a thermal diffusion test on the test battery, the test device includes a processor; The processor is used to trigger a thermal runaway in the first battery cell of the test battery. The power of the test battery meets the first preset condition, and the temperature of the test battery meets the second preset condition; The processor is further used to obtain the battery parameter information of the second battery cell in the test battery. The second battery cell and the first battery cell satisfy the first positional relationship; The processor is further used to determine whether thermal diffusion has occurred in the test battery according to the battery parameter information of the second battery cell.

15. The test device according to claim 14, characterized in that The temperature of the test battery meets the second preset condition, including: the temperature of the test battery is not less than 40 °C.

16. The test device according to claim 14 or 15, characterized in that, The power of the test battery meets the first preset condition, including: the state of charge of the test battery reaches 100%.

17. The test device according to any one of claims 14 to 16, characterized in that, The second battery cell and the first battery cell satisfy the first positional relationship, including: the second battery cell is adjacent to the first battery cell.

18. The test device according to any one of claims 14 to 17, characterized in that, The first battery cell is close to the central position inside the test battery, and / or, the first battery cell is surrounded by other battery cells inside the test battery.

19. The test device according to any one of claims 14 to 18, characterized in that, The processor is further used to: Before or after triggering a thermal runaway in the first battery cell of the test battery, turn on the cooling system of the test battery.

20. The test device according to claim 19, characterized in that, The cooling system is a water cooling system, and the processor is further used to: Control the water cooling system to perform water circulation for the first preset duration; Wherein, the first preset duration is determined according to at least one of the following information: the rated energy of the low-voltage power supply provided by the test battery, the rated capacity of the low-voltage power supply provided by the test battery, the rated voltage of the low-voltage power supply provided by the test battery, the upper limit value of the state of charge at which the test battery operates, the lower limit value of the state of charge at which the test battery operates, and the rated energy of the water pump.

21. The test device according to claim 20, wherein, The first preset duration is determined based on the following formula: W1 = C × V × (SOC1 - SOC2), T = W1 / W2 × 60, where W1 is the rated energy of the low-voltage power supply provided by the test battery, C is the rated capacity of the low-voltage power supply provided by the test battery, V is the rated voltage of the low-voltage power supply provided by the test battery, SOC1 is the upper limit value of the state of charge at which the test battery operates, SOC2 is the lower limit value of the state of charge at which the test battery operates, W2 is the rated energy of the water pump, and T is the first preset duration.

22. The test device according to any one of claims 14 to 21, characterized in that The processor is specifically configured to: When it is monitored that the battery parameter information meets at least one of the following conditions, determine that thermal diffusion has occurred in the test battery: The voltage of the second battery cell drops to exceed a preset ratio of the initial voltage, The temperature of the second battery cell reaches the temperature threshold, and The temperature rise rate of the second battery cell is not less than the first threshold and lasts for more than the second preset duration.

23. The test device according to any one of claims 14 to 22, characterized in that The processor is specifically configured to: Before triggering thermal runaway in the first battery cell of the test battery, control the heating device to heat the test battery to meet the second preset condition.

24. The testing device according to claim 23, wherein The processor is further configured to: When it is determined that thermal diffusion has occurred in the test battery, control the heating device to be removed from the test platform.

25. The test device according to any one of claims 14 to 24, characterized in that The processor is specifically configured to: Turn on the heating device in surface contact with the first battery cell so that the first battery cell meets at least one of the following conditions: The voltage of the first battery cell drops to exceed a preset ratio of the initial voltage, The temperature of the first battery cell reaches the temperature threshold, and The temperature rise rate of the first battery cell is not less than the first threshold and lasts for more than the second preset duration.

26. The test device according to any one of claims 14 to 25, characterized in that, The test battery is a battery installed with a customized frame.

27. A computer-readable storage medium, characterized in that, For storing a computer program, the computer program causes a computer to execute the test method according to any one of claims 1 to 13.

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