Thermal diffusion testing method, test device, and computer readable storage medium

Abstract

Embodiments of the present application provide a thermal diffusion testing method, a test device, and a computer readable storage medium. The method comprises: triggering thermal runaway in a first battery cell within a test battery, wherein the power level of the test battery satisfies a first preset condition, and the temperature of the test battery satisfies a second preset condition; acquiring battery parameter information of a second battery cell within the test battery, wherein the second battery cell and the first battery cell satisfy a first positional relationship; and on the basis of the battery parameter information of the second battery cell, determining whether thermal diffusion occurs in the test battery. The method, the test device, and the computer readable storage medium provided in the embodiments of the present application can improve the reliability and accuracy of thermal diffusion testing.

Description

Thermal diffusion testing method, testing device, and computer-readable storage medium

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410069352.6, filed on January 17, 2024, entitled “Method, test equipment and computer-readable storage medium for thermal diffusion testing,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The embodiments of the present application relate to the technical field of battery testing, and in particular to a method, testing equipment, and computer-readable storage medium for thermal diffusion testing. Background Art

[0004] The number of electric vehicle fires continues to rise, raising concerns about electric vehicle safety. Most electric vehicle fires are caused by thermal diffusion within the battery. Therefore, battery development urgently requires a battery-level thermal diffusion test to expose product defects and continuously refine battery design and manufacturing processes to enhance product quality.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a method, a testing device, and a computer-readable storage medium for thermal diffusion testing, which are conducive to improving the reliability and accuracy of thermal diffusion testing.

[0007] In a first aspect, a method for thermal diffusion testing is provided, comprising: triggering thermal runaway of a first battery cell in a test battery, the power level of the test battery meeting a first preset condition, and the temperature of the test battery meeting a second preset condition; obtaining battery parameter information of a second battery cell in the test battery, the second battery cell and the first battery cell meeting a first positional relationship; and determining whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell.

[0008] In an embodiment of the present application, thermal runaway is triggered in a first battery cell in a test battery, and whether thermal diffusion occurs in the test battery is determined based on battery parameter information of a second battery cell in the test battery that satisfies a first positional relationship with the first battery cell. Since the power level of the test battery is strictly controlled to meet a first preset condition and the temperature of the test battery is strictly controlled to meet a second preset condition before thermal runaway of the first battery cell is triggered, this helps to ensure the accuracy and reliability of the test results.

[0009] In a possible implementation, the temperature of the test battery satisfies a second preset condition, including: the temperature of the test battery is not less than 40° C.

[0010] In this embodiment, the temperature of the test battery is set to no less than 40° C., which is beneficial for covering the worst scenarios experienced in the later application stage, thereby making the test results more effective and reducing the risk of thermal diffusion.

[0011] In a possible implementation, the power level of the test battery satisfies a first preset condition, including: the state of charge of the test battery reaches 100%.

[0012] In this embodiment, before performing the heat diffusion test on the test battery, the SOC of the test battery is charged to 100%, which is beneficial for placing the test battery in a condition where heat diffusion is most likely to occur, thereby making the result of the heat diffusion test more reliable.

[0013] 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.

[0014] In this embodiment, when thermal runaway is detected in a battery cell in the test battery, real-time monitoring of battery parameter information of battery cells adjacent to the battery cell experiencing thermal runaway is beneficial for earlier detection of thermal diffusion in the test battery, thereby reducing the irreversible effects caused by thermal diffusion.

[0015] In a possible implementation, the first battery cell is close to a center position in the test battery, and / or the first battery cell is surrounded by other battery cells in the test battery.

[0016] In this embodiment, the first battery cell close to the center of the test battery and / or surrounded by other battery cells is selected as the target for triggering thermal runaway, making it more likely that the test battery will experience thermal diffusion, thereby improving the reliability of the thermal diffusion test.

[0017] In a possible implementation, before or after triggering the thermal runaway of the first battery cell in the test battery, the method further includes: starting a cooling system of the test battery.

[0018] In this embodiment, before or after triggering thermal runaway of the first battery cell in the test battery, the cooling system of the test battery is turned on, which is beneficial for taking into account the test battery's ability 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 flow into the market, thereby reducing the probability of thermal diffusion of the battery and improving the battery yield.

[0019] In one possible implementation, the cooling system is a water cooling system, and the method further includes: controlling the water cooling system to perform water circulation for a first preset time period, the first preset time period being 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 of the test battery, the lower limit value of the state of charge of the test battery, and the rated energy of the water pump.

[0020] In this embodiment, when thermal runaway of the battery under test is triggered, the water cooling system usually does not have high pressure and cannot perform cooling and cooling, and can only rely on water circulation to remove heat. Therefore, by controlling the length of time the water cooling system circulates water, it is beneficial to more accurately verify the test battery's ability to handle thermal runaway in the thermal diffusion test.

[0021] In one possible implementation, the first preset duration is determined based on the following formula: W1=C×V×(SOC1-SOC2), T=W1 / W2×60, wherein 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, SOC2 is the lower limit value of the state of charge of the test battery, W2 is the rated energy of the water pump, and T is the first preset duration.

[0022] In one possible implementation, determining whether thermal diffusion occurs in the test battery is based on the battery parameter information of the second battery cell, including: determining that thermal diffusion occurs in the test battery when the monitored battery parameter information satisfies at least one of the following conditions: the voltage of the second battery cell drops to a preset proportion exceeding 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 time period.

[0023] In this embodiment, when at least one of the following conditions is met: the voltage of the second battery cell drops to a preset proportion 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 greater than or equal to a first threshold and lasts for more than a second preset time period, it is determined that thermal diffusion has occurred in the test battery, and the performance of the test battery can be evaluated more accurately.

[0024] In a possible implementation, the method further includes: heating the test battery until a second preset condition is satisfied before triggering the thermal runaway of the first battery cell in the test battery.

[0025] In this embodiment, after the test battery is heated to meet the second preset condition, a thermal diffusion test is performed on the test battery, which is beneficial for covering the worst scenarios experienced in the later application stage, thereby making the test results more effective and reducing the risk of thermal diffusion.

[0026] In a possible implementation, the method further includes: when it is determined that thermal diffusion has occurred in the test battery, controlling a heating device to move out of the test platform, the heating device being used to heat the test battery until a second preset condition is satisfied.

[0027] In this embodiment, when it is determined that thermal diffusion has occurred in the test battery, the temperature increasing device is moved out of the test platform, which can reduce the impact of the thermal diffusion on the temperature increasing device.

[0028] In one possible implementation, 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 to a preset proportion exceeding 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 the first threshold and lasts for more than a second preset time period.

[0029] In this embodiment, the use of the triggered thermal runaway method can reduce the probability of damaging the external structure or sealing structure of the battery cell or the test battery, thereby making the simulated thermal runaway behavior as realistic as possible.

[0030] In one possible implementation, the test battery is a battery mounted on a custom frame.

[0031] In this embodiment, by installing a customized vehicle frame for the test battery, the environment of the thermal diffusion test can be made more realistic and the test results more accurate.

[0032] In a second aspect, a test device is provided for performing a thermal diffusion test on a test battery, the test device including a processor; the processor is used to trigger thermal runaway of a first battery cell in the test battery, the power of the test battery meets a first preset condition, and the temperature of the test battery meets a second preset condition; the processor is also used to obtain battery parameter information of a second battery cell in the test battery, the second battery cell and the first battery cell meet a first positional relationship; the processor is also used to determine whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell.

[0033] In a possible implementation, the temperature of the test battery satisfies a second preset condition, including: the temperature of the test battery is not less than 40° C.

[0034] In a possible implementation, the power level of the test battery satisfies a first preset condition, including: the state of charge of the test battery reaches 100%.

[0035] 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.

[0036] In a possible implementation, the first battery cell is close to a center position in the test battery, and / or the first battery cell is surrounded by other battery cells in the test battery.

[0037] In a possible implementation, the processor is further configured to: start a cooling system of the test battery before or after triggering thermal runaway of the first battery cell in the test system.

[0038] In one possible implementation, 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 a first preset time period, wherein the first preset time period 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 of the test battery, the lower limit value of the state of charge of the test battery, and the rated energy of the water pump.

[0039] In one possible implementation, the first preset duration is determined based on the following formula: W1=C×V×(SOC1-SOC2), T=W1 / W2×60, wherein 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, SOC2 is the lower limit value of the state of charge of the test battery, W2 is the rated energy of the water pump, and T is the first preset duration.

[0040] In one possible implementation, the processor is specifically used to determine 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 a preset proportion exceeding 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 a second preset time.

[0041] In a possible implementation, the processor is specifically configured to: before triggering thermal runaway of the first battery cell in the test battery, control the temperature increasing device to heat the test battery until a second preset condition is satisfied.

[0042] In a possible implementation, the processor is further configured to: when it is determined that heat diffusion occurs in the test battery, control the temperature increasing device to move out of the test platform.

[0043] In one possible implementation, the processor is specifically used to: turn 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 to a preset proportion exceeding 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 the first threshold and lasts for more than a second preset time period.

[0044] In one possible implementation, the test battery is a battery mounted on a custom frame.

[0045] In a third aspect, a chip is provided, comprising a processor for calling and running a computer program from a memory, so that a device equipped with the chip executes the method in the first aspect and any possible implementation of the first aspect.

[0046] 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 manner of the first aspect.

[0047] In a fifth aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program enables a computer to execute the method in the first aspect and any possible implementation manner of the first aspect.

[0048] In a sixth aspect, a computer program product is provided, comprising computer program instructions, which enable a computer to execute the method in the first aspect and any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0050] FIG1 shows a schematic exploded view of a test battery according to an embodiment of the present application.

[0051] FIG2 shows a first schematic block diagram of a method for thermal diffusion testing according to an embodiment of the present application.

[0052] FIG3 shows a second schematic block diagram of the method for thermal diffusion testing according to an embodiment of the present application.

[0053] FIG4 shows a third schematic block diagram of the method for thermal diffusion testing according to an embodiment of the present application.

[0054] FIG5 shows a fourth schematic block diagram of the method for thermal diffusion testing according to an embodiment of the present application.

[0055] FIG6 shows a fifth schematic block diagram of the method for thermal diffusion testing according to an embodiment of the present application.

[0056] FIG7 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.

[0057] FIG8 is a schematic diagram showing the positional relationship between the puncture points and the temperature sensors in the method of triggering thermal runaway by puncture according to an embodiment of the present application.

[0058] FIG9 shows a schematic flow chart of a method for thermal diffusion testing according to an embodiment of the present application.

[0059] FIG10 shows a schematic block diagram of a testing device according to an embodiment of the present application. DETAILED DESCRIPTION

[0060] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0061] In the description of this application, it should be noted that, unless otherwise specified, “multiple” means more than two; in addition, the terms “first”, “second”, “third”, etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0062] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, and electric trucks. They are even being used in a variety of fields, including military and aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0063] Due to manufacturing defects or improper use, batteries can experience thermal runaway in extreme cases, causing internal battery temperatures to rise. In severe cases, this can trigger a thermal runaway chain reaction, known as thermal diffusion or heat spread, leading to battery fires and explosions. While thermal runaway cannot be completely avoided, it can only be reduced in likelihood or mitigated in the event of damage. Therefore, during the battery development process, thermal diffusion testing is often performed on batteries to expose product defects, and battery design and manufacturing processes are continuously refined to mitigate the damage caused by thermal runaway and improve battery quality. However, current thermal diffusion test results often cannot accurately assess battery safety.

[0064] In view of this, an embodiment of the present application provides a method for thermal diffusion testing, which triggers thermal runaway of a first battery cell in a test battery and determines whether thermal diffusion occurs in the test battery based on battery parameter information of a second battery cell in the test battery that satisfies a 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 is strictly controlled to meet the second preset condition before triggering thermal runaway of the first battery cell, it is beneficial to ensure the accuracy and reliability of the test results.

[0065] FIG1 shows a schematic structural diagram of a test battery 10 according to an embodiment of the present application. As shown in FIG1 , the test battery 10 may include a plurality of battery cells 20. The test battery 10 also includes a housing 30, the interior of the housing 30 being a hollow structure, and a plurality of battery cells 20 being accommodated in the housing 30. FIG1 shows a possible implementation of the housing 30 according to an embodiment of the present application. As shown in FIG1 , the housing 30 may include two parts, referred to herein as a first part 31 and a second part 32, which are buckled together. The shapes of the first part 31 and the second part 32 may be determined according to the shapes of the plurality of battery cells 20 after being combined.

[0066] Figure 2 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 performed by a testing device, such as a host computer. As shown in Figure 2 , the method 100 includes some or all of the following:

[0067] S110 , triggering thermal runaway of a first battery cell in a test battery, the power level of the test battery meets a first preset condition, and the temperature of the test battery meets a second preset condition.

[0068] S120 , 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.

[0069] S130 , determining whether heat diffusion occurs in the test battery according to battery parameter information of the second battery cell.

[0070] The test battery in the embodiment of the present application may be as shown in FIG1 , that is, the test battery may include a plurality of battery cells, and the plurality of battery cells include at least a first battery cell and a second battery cell.

[0071] A thermal diffusion test is used to assess the potential safety risks associated with thermal diffusion caused by thermal runaway of a single battery cell in a test battery. In an embodiment of the present application, when performing a thermal diffusion test on a test battery, thermal runaway may first be triggered in a first battery cell in the test battery. Battery parameter information for a second battery cell in the test battery may then be obtained. Finally, based on the battery parameter information for the second battery cell, a determination is made as to whether thermal diffusion has occurred in the test battery.

[0072] In some embodiments, determining whether thermal diffusion occurs in the test battery can be done by judging whether thermal runaway also occurs in the second battery cell. For example, determining whether thermal runaway occurs in the second battery cell can be done by judging whether the temperature of the second battery cell reaches a certain value, thereby judging whether thermal diffusion occurs in the test battery.

[0073] In other embodiments, whether thermal diffusion has occurred in the test cell can be determined by determining whether the pressure within the test cell has reached a certain value. In other embodiments, whether thermal diffusion has occurred in the test cell can be determined by determining whether the smoke concentration within the test cell has reached a certain value. The embodiments of this application do not specifically limit how to determine whether thermal diffusion has occurred in the test cell.

[0074] In an embodiment of the present application, before triggering thermal runaway in a first battery cell in a test battery, the battery's charge level is set to meet a first preset condition, and the battery's temperature is set to meet a second preset condition. The first and second preset conditions can be pre-set based on the battery's actual operating conditions to cover the worst-case operating conditions. Furthermore, before conducting a thermal diffusion test on the test battery, the positional relationship between the first and second battery cells must also be pre-set. For example, the first and second battery cells must be separated by a preset number of battery cells. Once thermal runaway is determined for the first battery cell, the second battery cell can be located based on this pre-set positional relationship, and battery parameter information for the second battery cell can be obtained. In this case, before conducting a thermal diffusion test on the test battery, each battery cell may need to be modified. For example, each battery cell may be equipped with a built-in heating device for triggering thermal runaway, and each battery cell may be equipped with a sensor for obtaining battery parameter information. The modified airtightness should meet design requirements.

[0075] In other embodiments, it is also possible to directly specify the first and second battery cells before performing the thermal diffusion test on the test battery. Once thermal runaway is determined to have occurred in the first battery cell, the battery parameter information of the second battery cell can be directly obtained. In this case, before performing the thermal diffusion test on the test battery, it may only be necessary to integrate a heating device for triggering thermal runaway into the first battery cell, and to install sensors for obtaining battery parameter information in the first and second battery cells, without modifying the other battery cells in the test battery.

[0076] The battery parameter information in the embodiments of the present application refers to parameter information related to battery cells. More specifically, battery parameter information refers to parameter information that can be used to judge whether thermal runaway occurs. For example, battery parameter information can be voltage information, temperature information, or pressure information, etc. In some embodiments, battery parameter information can be obtained through sensors. For example, voltage information can be obtained through a voltage sensor, temperature information can be obtained through a temperature sensor, and pressure information can be obtained through a pressure sensor. Furthermore, the sensor can transmit the obtained battery parameter information to a host computer for the host computer to determine whether thermal runaway occurs in a battery cell in the test battery, or to determine whether thermal diffusion occurs in the test battery.

[0077] In an embodiment of the present application, thermal runaway is triggered in a first battery cell in a test battery, and whether thermal diffusion occurs in the test battery is determined based on battery parameter information of a second battery cell in the test battery that satisfies a first positional relationship with the first battery cell. Since the power level of the test battery is strictly controlled to meet a first preset condition and the temperature of the test battery is strictly controlled to meet a second preset condition before thermal runaway of the first battery cell is triggered, this helps to ensure the accuracy and reliability of the test results.

[0078] In some embodiments, the temperature of the test battery satisfies a second preset condition, including: the temperature of the test battery is not less than 40°C.

[0079] 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 whole vehicle are often more prone to thermal diffusion. During the battery development process, if the thermal diffusion test of the battery to be installed on the whole vehicle is carried out at room temperature, then the test result may be inaccurate. For example, if the thermal diffusion test result of the test battery at room temperature shows that thermal diffusion is not likely to occur, but the whole vehicle equipped with the test battery is in a high temperature scene for a long time, such as an exposed scene in the hot summer, then the test battery may still undergo thermal diffusion, which will lead to the failure of the thermal diffusion test during the battery development process. Therefore, in this case, conducting a thermal diffusion test on the test battery at high temperature, for example, setting the temperature of the test battery to not less than 40°C, is conducive to covering the worst 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.

[0080] Optionally, the temperature of the test cell may be between 40° C. and 50° C. For example, the temperature of the test cell is 40° C., 45° C., or 50° C.

[0081] In other embodiments, the temperature of the test battery satisfies the second preset condition, further comprising: 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, the temperature of the test battery can be set to 60°C before the thermal diffusion test.

[0082] In an actual vehicle scenario, the vehicle will record vehicle data, such as battery temperature data, but this data does not distinguish the actual vehicle usage scenario. Therefore, the second preset condition can be ultimately defined by conducting in-depth analysis and deduction of the vehicle data.

[0083] The definition logic of the second preset condition will be described in detail below with reference to specific embodiments.

[0084] Data source: More than 200,000 passenger cars were selected, covering more than 15 models. The battery chemical systems used include NCM ternary lithium materials and lithium iron phosphate LFP materials. These 200,000 passenger cars are mainly used in Jilin, Beijing, Shanghai and Guangzhou.

[0085] Data screening: The main usage scenarios of vehicles 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 (online); 8. Parking (offline); 9. After-sales maintenance; 10. Special scenarios (car washing / battery replacement, etc.). Considering that load, state of charge (SOC) and battery temperature are all characteristic parameters of harsh scenarios, through screening, it is concluded that the typical harsh scenarios for battery thermal runaway are high-temperature and high-load charging (fast charging), high-temperature and high-load driving (discharging) and off-line parking (exposure to the sun). Among them, high load refers to the passage of large current. For example, current / capacity>1 is considered high load. In addition, since the vehicle only has internal battery temperature data and lacks the battery's ambient temperature, the reference temperature is used, and summer afternoons (11:00-18:00) are considered high temperatures. Specifically, the temperature data recorded by the aforementioned 200,000 passenger vehicles in the afternoons between June 2022 and August 2022 in the three typical harsh scenarios mentioned above can be selected. In addition, since the battery is in a dormant state during the parking process, the internal battery temperature data cannot be detected. The time interval between the first frame time when the vehicle is awakened and the last frame time when it is parked can be used as the static time. When the static time is greater than 3 hours, it is considered that thermal equilibrium has been reached and the conditions for exposure to the sun are met.

[0086] Data processing: In actual use, there are three typical harsh scenarios. To obtain a weighted result, it is necessary to compare the duration of the data of the three scenarios, obtain the ratio, and finally obtain the weighted value of the temperature. See Table 1.

[0087] Table 1

[0088] Definition of the second preset condition: As shown in Table 1, 3σ = 47.3°C, Mean value = 37.6°C. Taking into account the different capacity ranges of different batteries, 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.

[0089] In another embodiment of the present application, the thermal diffusion test of the test battery can also be performed at room temperature. That is, before the thermal diffusion test, the test battery temperature is room temperature. Room temperature can generally be defined as a temperature below 0°C and less than 40°C. For example, before the thermal diffusion test, the test battery temperature is 10°C, 15°C, 20°C, or 25°C.

[0090] In some embodiments, the power level of the test battery satisfies a first preset condition, including: the SOC of the test battery reaches 100%. In other words, the test battery needs to be fully charged.

[0091] Specifically, the test battery can be charged with a standard method according to GB38031. That is, first discharge with a current specified by the manufacturer and not less than 13 to the discharge termination voltage specified in the manufacturer's technical conditions, and leave it for 1 hour (or a shelf time of not more than 1 hour provided by the manufacturer). Then charge according to the charging method provided by the manufacturer. If the manufacturer does not provide a charging method, the testing agency and the manufacturer shall negotiate to determine a suitable charging method, or charge according to the following method: charge with a constant current of not less than 13 specified by the manufacturer until the test battery reaches the charge termination voltage specified in the manufacturer's technical conditions, then switch to constant voltage charging, stop charging when the charging current drops to 0.05I1, and leave it for 1 hour after charging (or a shelf time of 1 hour provided by the manufacturer), where I1 is the rated current and I3 is 1 / 3 of the rated current.

[0092] In this embodiment, before performing the heat diffusion test on the test battery, the SOC of the test battery is charged to 100%, which is beneficial for placing the test battery in a condition where heat diffusion is most likely to occur, thereby making the result of the heat diffusion test more reliable.

[0093] In other embodiments, the thermal diffusion test can also be performed when the SOC of the test battery is at other values. For example, the thermal diffusion test can be performed on the test battery when the SOC of the test battery reaches 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95%. Since the vehicle is unlikely to be in the most demanding scenario in actual use, for example, the battery is fully charged for a long time in a high temperature environment. Therefore, the SOC of the test battery can be appropriately lowered during the test, which is beneficial to improving the battery yield.

[0094] 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.

[0095] Typically, when a battery cell experiences thermal runaway, if the thermal runaway problem is not addressed promptly, it is likely to spread to other cells in the battery, thereby causing thermal runaway in other cells. In particular, cells adjacent to the thermal runaway cell are the first to be affected and are most likely to be affected. Therefore, in the embodiments of the present application, when thermal runaway is detected in a test cell, real-time monitoring of battery parameter information of cells adjacent to the thermal runaway cell is performed, which facilitates earlier detection of thermal spread in the test cell, thereby reducing the irreversible effects of thermal spread.

[0096] In some other embodiments, the second battery cell may not be adjacent to the first battery cell. That is, if thermal runaway is detected in the first battery cell of the test battery, the battery parameter information of the second battery cell separated from the first battery cell by a preset number of battery cells may be monitored to determine whether thermal runaway occurs in the test battery.

[0097] In some embodiments, the first battery cell is located near a center position within the test cell, and / or the first battery cell is surrounded by other battery cells within the test cell.

[0098] For example, the test battery 10 in FIG1 includes 25 battery cells arranged along a first direction X. The first battery cell may be the 13th battery cell sequentially arranged from one end to the other along the first direction X, that is, the first battery cell is battery cell 21 in FIG1 . For another example, the first battery cell may be battery cell 22 in FIG1 , which is surrounded by battery cells 23 and 24.

[0099] In this embodiment, the first battery cell close to the center of the test battery and / or surrounded by other battery cells is selected as the target for triggering thermal runaway, making it more likely that the test battery will experience thermal diffusion, thereby improving the reliability of the thermal diffusion test.

[0100] In other embodiments, the first battery cell may also be selected in the following manner: 1. Select a battery cell at a location where heat dissipation and exhaust are blocked: usually the center of the battery is tested; 2. Select a battery cell at a location with a greater risk of high-voltage ignition: usually close to the high-voltage port; 3. Select a battery cell at a relatively weak location in the water cooling system: that is, a weak location in the water cooling pipeline.

[0101] In some embodiments, as shown in FIG3 , before or after triggering the thermal runaway of the first battery cell in the test battery, the method 100 further includes: S140 , starting a cooling system of the test battery.

[0102] Optionally, the cooling system can be a liquid cooling system, an air cooling system, or a direct cooling system. An air cooling system uses air as the heat exchange medium to cool the battery. A liquid cooling system uses liquid as the heat exchange medium to cool the battery. A direct cooling system uses a refrigerant as the heat exchange medium, absorbing heat during the gas-liquid phase transition to cool the battery.

[0103] In some embodiments, the cooling system of the test battery may be turned on before triggering thermal runaway of the first battery cell in the test battery, so that the cooling system can be used to reduce the probability of thermal runaway or thermal diffusion during the entire thermal diffusion test process.

[0104] In other embodiments, the cooling system of the test battery may be turned on after triggering thermal runaway of the first battery cell in the test battery, so that the cooling system can be used to reduce the impact of thermal runaway, for example, reduce the probability of thermal diffusion.

[0105] In this embodiment, before or after triggering thermal runaway of the first battery cell in the test battery, the cooling system of the test battery is turned on, which is beneficial for taking into account the test battery's ability 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 flow into the market, thereby reducing the probability of thermal diffusion of the battery and improving the battery yield.

[0106] In some embodiments, as shown in Figure 3, the cooling system is a water cooling system, and the method 100 also includes: S150, controlling the water cooling system to perform water circulation for a first preset time period, wherein the first preset time period 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 SOC upper limit value of the test battery operation, the SOC lower limit value of the test battery operation, and the rated energy of the water pump.

[0107] During actual vehicle use, when thermal runaway is triggered, the battery will report the fault to the vehicle and request that the high voltage be disconnected. When the water cooling system loses high pressure, the compressor cannot be started, meaning there is no cooling power. At this time, cooling can only be achieved through a circulating water pump. Because cooling is not possible at this time, heat can only be removed through circulation. Therefore, it is necessary to refer to the vehicle's strategy execution and consider the most demanding working conditions.

[0108] Similarly, during the thermal diffusion test, it is possible to first determine 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 performed under the most stringent working conditions, that is, the test battery is set to a water circulation non-triggerable mode. Once the first battery cell in the test battery is triggered to undergo thermal runaway, the water cooling system does not cool and does not circulate. The probability of thermal diffusion occurring in the test battery subjected to the thermal diffusion test under this working condition 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 a water circulation triggerable mode. Once the first battery cell in the test battery is triggered to undergo thermal runaway, the water cooling system only circulates water and does not cool. The water cooling flow rate can refer to the vehicle strategy.

[0109] In some embodiments, determining whether the water circulation of the water cooling system can be triggered can be performed after triggering the 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 circulate water. Once it is determined that the water circulation of the water cooling system cannot be triggered, the water cooling system is controlled not to circulate water.

[0110] In other embodiments, the determination of whether the water circulation of the water cooling system can be triggered can also be performed before triggering the thermal runaway of the first battery cell. In this case, once it is determined that the water circulation of the water cooling system can be triggered, the subsequent thermal diffusion test process will be executed by default in a mode in which the water circulation of the water cooling system can be triggered. If it is determined that the water circulation of the water cooling system cannot be triggered, the subsequent thermal diffusion process will be executed by default in a mode in which the water circulation of the water cooling system cannot be triggered.

[0111] Optionally, the first preset duration can also be pre-set in combination with actual working conditions. In some embodiments, the first preset duration is less than 1 hour. For example, the first preset duration can be 30 minutes.

[0112] In some embodiments, 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 SOC value of the test battery, the lower limit SOC value of the test battery, and the rated energy of the water pump.

[0113] 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 electrical 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 at 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 a water pump usually refers to the maximum flow rate and range that the water pump can provide under specified conditions.

[0114] The upper limit of the SOC for a test battery depends on the performance and life of the test battery. For example, the upper limit of the SOC for a battery should typically be between 80% and 90%. The lower limit of the SOC for a test battery depends on the type and performance of the test battery. For example, for a lead-acid battery, the lower limit is typically 10%, while for a lithium-ion battery, the lower limit is typically 0%.

[0115] In this embodiment, when thermal runaway is triggered in the battery under test, the water cooling system usually does not have high pressure and cannot perform cooling and cooling, and can only rely on water circulation to remove heat. Therefore, by controlling the length of time the water cooling system circulates water, it is beneficial to more accurately verify the test battery's ability to handle thermal runaway in the thermal diffusion test.

[0116] In some embodiments, the first preset duration is determined based on the following formula: W1=C×V×(SOC1-SOC2), T=W1 / W2×60, wherein 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 of the test battery, in %; SOC2 is the lower limit value of the SOC of the test battery, 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.

[0117] In some embodiments, as shown in Figure 4, S130, that is, determining whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell, includes: S131, determining that thermal diffusion occurs in the test battery when it is monitored that 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 to a preset proportion 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 a second preset time.

[0118] That is to say, a voltage sensor and a temperature sensor can be set in the second battery cell. After the thermal runaway of the first battery cell is triggered, 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 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 implicated by the first battery cell, and then it can be determined that thermal diffusion has occurred in the test battery.

[0119] In some embodiments, only one of the above conditions may need to be determined for the battery parameter information of the second battery cell. For example, only whether the voltage of the second battery cell has dropped to a preset ratio of the initial voltage may be determined. In another example, only whether the temperature of the second battery cell has reached a temperature threshold may be determined. In another example, only whether the temperature rise rate of the second battery cell is not less than a first threshold and lasts for at least a second preset duration may be determined.

[0120] It should be understood that if any of the above conditions is not met, to ensure the reliability of heat diffusion, several of the above conditions may be combined to determine if thermal runaway has not occurred in the second battery cell. For example, thermal runaway may be considered to have occurred in the second battery cell 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 a temperature threshold. For another example, thermal runaway may be considered to have occurred in the second battery cell when the temperature of the second battery cell reaches a temperature threshold and the rate of temperature rise of the second battery cell is not less than a first threshold and persists for at least a second preset duration.

[0121] In some embodiments, determining whether thermal diffusion occurs in the test battery is based on the battery parameter information of the second battery cell, including: determining that thermal diffusion occurs in the test battery when the battery parameter information of the second battery cell is monitored to meet at least one of the following conditions: the voltage of the second battery cell drops to 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 seconds.

[0122] It should be understood that the above-mentioned preset ratio, temperature threshold, first threshold and second preset time can be adjusted according to actual conditions.

[0123] In this embodiment, when at least one of the following conditions is met: the voltage of the second battery cell drops to a preset proportion 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 a second preset time period, it is determined that thermal diffusion has occurred in the test battery, and the performance of the test battery can be evaluated more accurately.

[0124] In some embodiments, as shown in FIG5 , the method 100 further includes: S160 , heating the test battery until a second preset condition is satisfied before triggering the thermal runaway of the first battery cell in the test battery.

[0125] Optionally, before conducting the thermal diffusion test, the test battery may be preheated using a heating device. For example, the heating device may be an incubator. The test battery may be placed in the incubator and the incubator temperature may be set. For example, the incubator temperature may be set to greater than or equal to 55°C. The incubator may then be turned on to heat the test battery. When the temperature sensor within the test battery detects that the test battery temperature is 55°C, the incubator stops heating the test battery.

[0126] If the test environment does not have a temperature chamber, water cooling and heating can also be used to heat the test battery until the second preset condition is met.

[0127] In this embodiment, after the test battery is heated to meet the second preset condition, the test battery is subjected to a thermal diffusion test, which is beneficial for covering the worst scenarios experienced in the later application stage, thereby making the test results more effective and reducing the risk of thermal diffusion.

[0128] In some embodiments, as shown in FIG5 , the method 100 further includes: S170 , when it is determined that heat diffusion occurs in the test battery, controlling a heating device to move out of the test platform, the heating device being used to heat the test battery until a second preset condition is satisfied.

[0129] Optionally, the heating device can be removed from the test platform manually or under the control of 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 exchange information with the heating device to control the heating device to be removed from the test platform.

[0130] Optionally, the heating device is a heating device with a slide rail.

[0131] In this embodiment, when it is determined that thermal diffusion has occurred in the test battery, the temperature increasing device is moved out of the test platform, which can reduce the impact of the thermal diffusion on the temperature increasing device.

[0132] In some embodiments, as shown in Figure 6, S110, i.e., triggering thermal runaway of the first battery cell in the test battery, includes: S111, 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 to a preset proportion 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 the first threshold and lasts for more than a second preset time.

[0133] Before performing the heat diffusion test on the test battery, the test battery may be modified first, that is, at least a heating device is installed in the test battery so that the heating device contacts the surface of the first battery cell.

[0134] In some embodiments, a planar or rod-shaped heating device can be used, and its surface should be covered with ceramic, metal, or an insulating layer. For a block-shaped heating device with the same size as a battery cell, the heating device can be used to replace one of the battery cells and directly contact 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, and the heating surface of the heating device should be 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. When thermal runaway occurs or the temperature monitored by the temperature sensor reaches 300°C, heating is stopped.

[0135] Table 2

[0136] In other embodiments, a heating device may be disposed within the first battery cell, i.e., within the housing of the first battery cell. For example, the heating device may be connected to the inner wall of the housing of the first battery cell. In another example, the heating device may be connected to the electrode assembly within the first battery cell, such as by sandwiching the heating device between two electrode assemblies.

[0137] The first battery cell requires not only a heating device but also a sensor, such as a temperature sensor, to monitor whether thermal runaway has occurred. The corresponding positions of the temperature sensor and heating device can be as shown in Figure 7, with the temperature sensor placed on the opposite side of the heating device. The temperature data should be sampled at an interval of less than 1 second, with an accuracy requirement of ±2°C.

[0138] In this embodiment, the use of the triggered thermal runaway method can reduce the probability of damaging the external structure or sealing structure of the battery cell or the test battery, thereby making the simulated thermal runaway behavior as realistic as possible.

[0139] Optionally, the size of the heating film can be 30*30mm, and its resistance can be approximately 50Ω. Specifically, the heating film can be led out of the test battery and connected to an external voltage greater than 42V. When the first battery cell in the test battery experiences thermal runaway, heating stops.

[0140] In other embodiments, a needle puncture method can also be used to trigger thermal runaway. Specifically, the puncture material is steel, the needle diameter is greater than 3mm to 8mm, the needle tip is conical with an angle of 20° to 60°, and the puncture speed is 0.1mm / s to 10mm / s. The location and direction that can trigger thermal runaway in the first battery cell are selected, for example, perpendicular to the electrode of the first battery cell. When triggering the puncture, the temperature sensor should be positioned as close to the puncture point as possible, as shown in Figure 8.

[0141] In some embodiments, triggering thermal runaway of a first battery cell in a test battery includes: turning on a heating device in contact with a 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 to 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 seconds.

[0142] It should be understood that the method for determining whether thermal runaway occurs in the first battery cell can refer to the method for determining whether thermal runaway occurs in the second battery cell, and for the sake of brevity, it is not described here in detail.

[0143] In some embodiments, the test battery is a battery mounted on a custom frame.

[0144] Since batteries are often installed in the chassis of a vehicle, they are not in a free state. If thermal runaway occurs, this can affect the exhaust path. Therefore, during thermal diffusion testing, the battery should be recreated as closely as possible in the vehicle. The frame should be customized and installed based on the clearance between the battery and the frame and the shielding of the pressure relief mechanism. This ensures a more realistic thermal diffusion test environment and more accurate test results.

[0145] After the thermal diffusion test results are obtained, the test battery can be left to stand for 2 hours, or the 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 check whether the test battery has any fire, explosion or other phenomena.

[0146] In some embodiments, before performing a thermal diffusion test on a test battery, the test battery needs to be in the following working mode: 1. The power supply line is powered on, the wake-up signal is activated, CAN communication and other initialization functions are activated, and other functions are not enabled; or, 2. All protective devices that affect the function of the test battery and are related to the test results should be in normal operating condition, and all relevant main contactors used for discharge should be closed.

[0147] Before performing a thermal diffusion test on the test battery, the test battery needs to be pre-processed as follows. Specifically, the test battery is first subjected to an insulation test. The measurement voltage used should be 1.5 times the nominal voltage of the test battery or 500 (dc), whichever is higher. The applied voltage should be long enough to obtain a stable reading. The recommended measurement time is 30s. Secondly, a communication check is performed 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 the voltage, temperature and other samples are checked for sharp changes and no fault signals are reported.

[0148] Fig. 9 shows a schematic flow chart of a method 200 for thermal diffusion testing according to an embodiment of the present application. Optionally, as shown in Fig. 9 , the method 200 may include some or all of the following contents.

[0149] S201 , pre-processing the test battery. For example, this includes performing an insulation test on the test battery. Another example includes performing a communication check on the test battery. Another example includes charging the test battery to 100% SOC.

[0150] S202: Modify the test battery. For example, a heating device may be installed inside the test battery. Another example is installing the test battery on a custom vehicle frame.

[0151] S203: Place the test battery in a temperature chamber and heat the test battery until a second preset condition is satisfied, for example, heating the test battery to 55°C.

[0152] S204: Select a triggering method to trigger the first battery cell in the test battery to cause thermal runaway. For example, a heating device in contact with the surface of the first battery cell may be turned on to heat the first battery cell until thermal runaway occurs.

[0153] S205 , triggering water circulation of the water cooling system of the test battery.

[0154] S206 , not triggering the water circulation of the water cooling system of the test battery.

[0155] S207: If the water circulation of the water cooling system is triggered, the cycle duration can be calculated according to the formula. For example, the cycle 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 of the SOC of the test battery, in %; SOC2 is the lower limit of the SOC of the test battery, 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 minutes.

[0156] S208: If the water circulation of the water cooling system cannot be triggered, the water cooling system does not circulate.

[0157] At step S209, it can be further determined whether the thermal runaway condition has spread to a second battery cell. For example, similar to determining whether thermal runaway has occurred in the first battery cell, the monitored battery parameter information of the second battery cell can be used to determine whether thermal runaway has occurred in the second battery cell. Once thermal runaway has occurred in the second battery cell, it can be assumed that the thermal runaway condition of the first battery cell has spread to the second battery cell.

[0158] S210 , if it is determined that the heat has spread to the second battery cell, the incubator is moved out of the test platform.

[0159] S211: If it is determined that the radiation has not spread to the second battery cell, the heating may continue at a constant temperature until the test is completed.

[0160] The thermal diffusion test method of an embodiment of the present application is described in detail above. The test equipment of an embodiment of the present application will be described in detail below in conjunction with Figure 10. The technical features described in the method embodiment are applicable to the following device embodiments.

[0161] Figure 10 shows a schematic block diagram of a test device 300 according to an embodiment of the present application. As shown in Figure 10 , the test device 300 includes some or all of the following contents.

[0162] Processor 310 is used to trigger thermal runaway of a first battery cell in a test battery, where the charge of the test battery satisfies a first preset condition and the temperature of the test battery satisfies a second preset condition; processor 310 is also used to obtain 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; processor 310 is also used to determine whether thermal diffusion occurs in the test battery based on the battery parameter information of the second battery cell.

[0163] Optionally, in the embodiment of the present application, the temperature of the test battery satisfies a second preset condition, including: the temperature of the test battery is not less than 40°C.

[0164] Optionally, in the embodiment of the present application, the power level of the test battery satisfies a first preset condition, including: the state of charge of the test battery reaches 100%.

[0165] Optionally, in the embodiment of the present application, 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.

[0166] Optionally, in the embodiment of the present application, the first battery cell is close to the center position in the test battery, and / or the first battery cell is surrounded by other battery cells in the test battery.

[0167] Optionally, in the embodiment of the present application, the processor 310 is further configured to: start a cooling system of the test battery before or after triggering thermal runaway of the first battery cell in the test battery.

[0168] Optionally, in an embodiment of the present application, the cooling system is a water cooling system, and the processor 310 is further used to: control the water cooling system to perform water circulation for a first preset time period, and the first preset time period 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 SOC upper limit value of the test battery operation, the SOC lower limit value of the test battery operation, and the rated energy of the water pump.

[0169] Optionally, in an embodiment of the present application, the first preset duration is determined based on the following formula: W1=C×V×(SOC1-SOC2), T=W1 / W2×60, wherein 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 SOC of the test battery, SOC2 is the lower limit value of the SOC of the test battery, W2 is the rated energy of the water pump, and T is the first preset duration.

[0170] Optionally, in an embodiment of the present application, the processor 310 is specifically used to: determine 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 a preset proportion exceeding 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 a second preset time period.

[0171] Optionally, in an embodiment 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 temperature increasing device to heat the test battery to meet a second preset condition.

[0172] Optionally, in an embodiment of the present application, the processor 310 is further configured to: when it is determined that thermal diffusion has occurred in the test battery, control the temperature increasing device to be moved out of the test platform.

[0173] Optionally, in an embodiment of the present application, the processor 310 is specifically used to: turn 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 to a preset proportion exceeding 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 the first threshold and lasts for more than a second preset time period.

[0174] Optionally, in an embodiment of the present application, the test battery is a battery mounted on a customized frame.

[0175] Optionally, as shown in FIG10 , the testing 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] The memory 320 may be a separate device independent of the processor 310 , or may be integrated into the processor 310 .

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

[0178] It should be understood that each module or unit in the testing device 300 can implement the corresponding process in the method of thermal diffusion testing provided in the embodiment of the present application. For the sake of brevity, they will not be described here in detail.

[0179] An embodiment of the present application also provides a chip, including a processor, for calling and running a computer program from a memory, so that a device equipped with the chip executes the methods of the various embodiments of the present application described above.

[0180] It should be understood that the processor of the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can 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, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0181] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may 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 may be a random access memory (RAM), which is used as an external cache. By way of example and 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), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus 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 enables 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, they are not repeated here.

[0184] An embodiment of the present application also provides 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 enable 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, they are not repeated here.

[0186] The embodiment of the present application also provides a computer program.

[0187] Optionally, the computer program can be applied to the test equipment in the embodiments of the present application. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the test equipment in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0188] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for thermal diffusion testing, characterized in that, Including: Triggering a thermal runaway of a first battery cell in a 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 occurs in the test battery according to the battery parameter information of the second battery cell.

2. The method according to claim 1, characterized in that 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 in the test battery, and / or, the first battery cell is surrounded by other battery cells in the test battery.

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

7. The method according to claim 6, characterized in that, 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 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.

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 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 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 a thermal runaway of a first battery cell in a test battery, heating the test battery to meet the second preset condition.

11. The method according to claim 10, characterized in that, 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 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 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.

13. The method according to any one of claims 1 to 12, characterized in that, The test battery is a battery installed with a customized vehicle 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 thermal runaway of the first battery cell in the test battery. The test The battery's power 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 a 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, wherein 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 a 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 thermal runaway of the first battery cell in the test battery, turn on the cooling system of the test battery.

20. The testing 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 a water circulation for a 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 testing 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: determine 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 a first threshold and lasts for more than a 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 test device according to claim 23, wherein The processor is further configured to: control the heating device to be removed from the test platform when it is determined that thermal diffusion has occurred in the test battery.

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 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.

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 vehicle 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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