Whole vehicle thermal diffusion test method for new energy vehicle

Abstract

To provide a whole vehicle thermal diffusion test method for a new energy vehicle.SOLUTION: The method includes the steps of: performing an initial modification to the battery system, triggering the battery pack to generate thermal runaway, and monitoring the battery system for changes in state; using a video capture device to capture video of the vehicle after thermal runaway, and monitoring whether or not there is smoke, fire, or explosion inside and outside the vehicle and in the battery, and the corresponding time; and collecting temperature data of the surface of contact objects in the passenger compartment, gas concentration data of the high-temperature exhaust smoke in the passenger compartment, and temperature data of the high-temperature exhaust smoke, and comparing the temperature data of the surface of contact objects in the passenger compartment, gas concentration data, and temperature data of the high-temperature exhaust smoke with corresponding safety standards, and evaluating the thermal diffusion capability of the complete vehicle based on the comparison result. The invention provides basis and guidance for actual product testing, improving the safety and reliability of verified products.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the field of thermal runaway protection in new energy vehicles, and in particular to a thermal diffusion test method for completed new energy vehicles. [Background technology]

[0002] In recent years, as the integration of new energy vehicles (NEVs) into complete vehicles has increased, new battery system architectures such as cell-to-chassis (CTC) and cell-to-body (CTB) have emerged, and an increasing number of new energy vehicle manufacturers are establishing their own battery factories. The industry's focus on battery system safety has shifted from the safety of individual components to the safety of the entire vehicle. On the one hand, there is structural safety, which protects both sides of the battery system through the vehicle's frame. On the other hand, there is functional safety, which strengthens the entire system by highly integrating the battery system's control strategy with the vehicle's complete vehicle strategy. This presents a challenge: testing a single component alone cannot fully reflect the actual safety level of the vehicle. The strong correlation between the thermal safety of battery systems and vehicle fires has become a hot topic of industry attention.

[0003] With the publication and implementation of GB 38031-2020 "Safety Requirements for Electric Vehicle Traction Batteries," the thermal diffusion test of battery systems has been introduced into product announcement management for the first time, and the related requirements and test methods have made a great contribution to improving product quality.

[0004] To improve the thermal safety of battery systems, the industry is actively developing new technologies and products. These include Ningde's Qilin battery, Beehive Energy's Dragon Scale Shell battery, SAIC's Rubik's Cube battery, and SAIC's Magazine-type battery. These products achieve high thermal safety levels for battery systems primarily through passive protection, active thermal management, and early warning control. Passive protection uses low thermal conductivity materials to confine the heat of a runaway battery cell to a specified spatial range without affecting the surrounding batteries. Active thermal management activates a forced cooling system to remove the heat generated by the battery runaway when thermal runaway occurs. Early warning control uses parameter recognition to issue an early warning of battery runaway and take effective shutdown measures to reduce the probability of battery runaway. Looking at the current technology applications in products, passive protection and active thermal management are the main technologies, and improving the maturity of early warning and control technology remains a challenge.

[0005] Although many new technologies, structures, and methods have been developed and applied, products still suffer from active events such as runaway and fire. Therefore, the industry urgently needs to consider the impact of the vehicle's actual layout and installation method on component-level testing methods. For example, adding a body covering structure to the vehicle body can increase the strength of the entire battery system and reduce the amount of deformation of the upper cover at the moment of battery cell runaway. Currently, many companies are beginning to conduct thermal safety tests on completed new energy vehicles to verify the thermal safety protection technology level of their products. However, thermal safety testing of completed vehicles has brought about a significant problem: the standards and evaluation systems for thermal safety testing of completed vehicle-level products are lacking in the specifications of conventional technologies.

[0006] The GB 38031-2020 national standard does not clearly specify the test conditions and methods for finished vehicles, nor does it clearly specify how to judge the test results. Therefore, in the new stage of product development, it is necessary to supplement the relevant technical details, which is also one of the main reasons for initiating the revision of the standard.

[0007] Therefore, based on the recognition that it is necessary to establish a thermal diffusion test method at the finished vehicle level as soon as possible, this invention provides a guideline basis and guidelines for actual product testing from three perspectives, including test conditions, test methods, and evaluation systems, and proposes a thermal safety test method at the finished vehicle level to improve the safety and reliability of verified products. Summary of the Invention

[0008] The present invention aims to provide a thermal diffusion test method for completed new energy vehicles, which can provide basis and guidelines for actual product testing and improve the safety and reliability of the tested products.

[0009] In order to achieve the above object, the present invention provides the following solutions.

[0010] The thermal diffusion test method for a completed new energy vehicle according to the present invention includes: determining a charging method of the battery system of the vehicle under test and correspondingly adjusting the state of charge of the battery system according to the charging method; performing an initial modification to the battery system that meets a predetermined modification standard; triggering a battery pack in the battery system to cause thermal runaway and recording state information of the battery pack; and monitoring a state change situation of the battery system after the thermal runaway based on the state information of the battery pack, wherein the state information includes an instrument display SOC, a temperature in the battery pack, and a voltage in the battery pack; a step of using a video capture device to perform video capture of the test vehicle after thermal runaway, acquiring video data, and monitoring the presence or absence of smoke, ignition, or explosion phenomena in the passenger compartment, outside the vehicle, and battery system of the test vehicle and the corresponding times based on the video data, wherein the video capture device is disposed at locations where the passenger compartment, outside the vehicle, and battery system of the test vehicle are located, and the video capture device disposed outside the vehicle satisfies a predetermined coverage range; collecting temperature data of a surface of a contact object in the passenger compartment by a first temperature sensor disposed in the passenger compartment; a step of collecting gas concentration data of the high-temperature exhaust fumes in the passenger compartment by a gas concentration sensor group and collecting temperature data of the high-temperature exhaust fumes in the passenger compartment by a second temperature sensor, wherein the high-temperature exhaust fumes contain CO, CO2 and O2, and the gas concentration sensor group and the second temperature sensor are both installed at positions corresponding to the air conditioner outlet and the mouth and nose of a human body in the passenger compartment; A process of comparing the temperature data of the surface of contact objects in the passenger compartment, the gas concentration data, and the temperature data of the high-temperature exhaust smoke with corresponding safety standards, and evaluating the thermal diffusion capacity of the completed test vehicle based on the corresponding comparison results.

[0011] Optionally, the predetermined modification standard is to maintain the integrity of the normal connections of the high and low voltage circuits in the completed vehicle, as well as the integrity of the existing thermal protection structure.

[0012] Optionally, the predetermined coverage range is 1.2 m from both the front and rear of the vehicle, and 0.8 m from both sides of the vehicle body.

[0013] Optionally, the safety standard for surface temperature data of the contact object in the passenger compartment is 48°C.

[0014] Optionally, the safety standard for the CO concentration data is a CO concentration of 15 mg / m 3 or less, or the CO concentration is 420 ppm or less in 10 min. The safety standard for the CO2 concentration data is 9839 ppm or less at 15 min. The safety standard for the O2 concentration data is an O2 concentration of 12% or more.

[0015] Optionally, the safety standard of the temperature data of the high-temperature flue gas is 70°C.

[0016] Optionally, the method further comprises: a step of obtaining temperature field data by using a thermograph arranged within the predetermined coverage area to acquire the temperature distribution status of the outer surface of the test vehicle and the diffusion status of exhaust smoke and flames after thermal runaway; and determining whether the vehicle under test will cause damage to facilities or personnel in the external environment after thermal runaway based on the temperature field data.

[0017] Optionally, the method further comprises: acquiring a battery management system message and a completed vehicle message of the vehicle under test after a thermal runaway; The method includes a step of monitoring whether an abnormality occurs in the transmission of the first warning signal of the vehicle under test based on the battery management system message and the completed vehicle message, and the first warning signal includes temperature abnormality, battery thermal runaway, turn signal lighting, horn honking, or door unlocking.

[0018] Optionally, the method further comprises: The method includes a step of monitoring whether the door handle in the passenger compartment can be unlocked after the thermal runaway based on the video data, and determining whether the vehicle is convenient for occupants to escape or rescue after the thermal runaway.

[0019] Optionally, the method further comprises: The method includes a step of monitoring whether or not an audio, optical warning signal, and instrument warning occurs in the vehicle after thermal runaway based on the video data.

[0020] According to the specific embodiments provided by the present invention, the present invention has the following technical effects:

[0021] The present invention provides a thermal diffusion test method for completed new energy vehicles, which can ensure a certain degree of safety after thermal runaway of existing battery systems through initial modifications to the battery system. Video capture devices installed within a specified coverage area can monitor the vehicle test phenomenon after thermal runaway, comprehensively capturing video data from all angles, improving the monitoring effect. New safety standards can be set according to the temperature data of contact surfaces in the passenger compartment, gas concentration data, and temperature data of high-temperature exhaust smoke, thereby more accurately and reliably evaluating the thermal diffusion protection capability of completed vehicles. [Brief explanation of the drawings]

[0022] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. Of course, the drawings described below are only a part of the embodiments of the present invention, and those skilled in the art can devise other drawings based on these drawings without any creative efforts.

[0023] [Figure 1] 1 is a flowchart of a thermal diffusion test method for a completed new energy vehicle according to a first embodiment of the present invention; [Figure 2] 1 is a schematic diagram showing the arrangement position of a video capture device according to a first embodiment of the present invention. [Figure 3] FIG. 1 is a diagram showing the internal structure of a computer device. DETAILED DESCRIPTION OF THE INVENTION

[0024] The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. However, the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without any creative efforts shall fall within the protection scope of the present invention.

[0025] The present invention aims to provide a thermal diffusion test method for finished new energy vehicles to provide basis and guidelines for actual product testing and improve the safety and reliability of the products being verified.

[0026] In order to make the above objects, features and advantages of the present invention clearer, the present invention will be described in more detail below in conjunction with drawings and specific embodiments.

[0027] As the integration of new energy vehicles in complete vehicles increases, the safety of battery systems in the industry has shifted from the safety of individual components to the safety of entire vehicle systems. The test standards and evaluation systems for thermal safety testing of complete vehicles are lacking in the existing specifications. Based on the thermal diffusion test methods and requirements of battery systems in GB 38031-2020, this invention proposes a complete vehicle-level thermal diffusion test method for new energy vehicles from three aspects: test conditions, test methods, and evaluation systems.

[0028] Example 1 Test conditions: Regarding thermal safety tests at the finished vehicle level for new energy vehicles, the test object is a finished new energy vehicle, and the test conditions are set as follows, with reference to GB 38031-2020:

[0029] Environmental conditions: Tests should be conducted indoors or at a temperature of 0°C or higher, a relative humidity of 10% to 90%, an atmospheric pressure of 86 kPa to 106 kPa, and a wind speed of 2.5 km / h or less. Considering the influence of the test environment on test results and the repeatability and reproducibility of test results, it is recommended that tests be conducted indoors.

[0030] Test Method: As shown in FIG. 1, the thermal diffusion test method for a completed new energy vehicle in this embodiment includes the following steps S1 to S7.

[0031] Step S1: Determine the charging method of the battery system of the test vehicle and appropriately adjust the state of charge of the battery system according to the charging method. Specifically, set the state of charge (SOC) of the test vehicle to a predetermined value before starting the test.

[0032] 1) For vehicles designed for external charging, the SOC shall be adjusted to at least 95% of the normal SOC operating range as specified by the manufacturer.

[0033] 2) For vehicles designed to be charged solely by vehicle energy, their SOC shall be similarly adjusted to above 90% of their operating range.

[0034] Step S2: Perform an initial modification to the battery system that meets a predetermined modification standard, specifically, the predetermined modification standard is intended to maintain the integrity of the normal high-voltage circuit connections and low-voltage circuit connections of the completed vehicle and the integrity of the existing thermal protection structure.

[0035] To trigger the battery to thermal runaway, certain modifications must be made to the completed vehicle before testing, such as placing a heating device between the cells or drilling a specific location on the battery system housing so that the needle can pierce the target cell. The test sample should be modified as little as possible during testing, and the manufacturer must submit a list of modifications.

[0036] Currently, a typical initial modification method that meets the current standard requirements involves replacing some battery cells with a flat heating sheet. This modification method involves replacing the actual battery cells with a heating sheet, which may destroy the high-voltage connections of the entire pack. Furthermore, fixing the heating sheet usually requires destroying the original insulating material or adding an additional protective structure, all of which disrupt the actual state of the original battery system and result in the battery system being subjected to test conditions that are less severe after modification than in the original state. Therefore, the present invention limits the predetermined modification standards that the initial modification must meet.

[0037] Step S3: Trigger the battery pack in the battery system to generate thermal runaway, and record the state information of the battery pack. After the thermal runaway, monitor the state change situation of the battery system based on the state information of the battery pack, where the state information includes the instrument display SOC, the temperature in the battery pack, and the voltage in the battery pack.

[0038] Specifically, in the thermal safety test method for new energy vehicles, the thermal runaway trigger method, trigger target, and monitoring point scheme can all refer to the current GB 38031-2020 standard. Considering the need to avoid damaging the high and low voltage circuits and thermal protection structure of the battery system, the original standard's proposal to use a heating device instead of a battery has been deleted. Regarding the trigger method, methods such as needle pricking, built-in heating, or overcharging may be selected, or other trigger methods may be automatically selected. The trigger target selection method is consistent with the original standard, selecting a cell close to the center of the battery pack or a battery cell surrounded by other battery cells.

[0039] Step S4: Use a video capture device to capture video of the test vehicle after thermal runaway to obtain video data, and based on the video data, monitor the presence or absence of smoke, ignition, or explosion phenomena in the passenger compartment, outside the vehicle, and battery system of the test vehicle, and the corresponding times. The video capture device is placed in the passenger compartment, outside the vehicle, and at the locations where the battery system is located, and the video capture device placed outside the vehicle meets a predetermined coverage range.

[0040] Preferably, the predetermined coverage range is 1.2 m from both the front and rear of the vehicle, and 0.8 m from both sides of the vehicle body.

[0041] Specifically, the main difference between this invention and the conventional battery system-level thermal diffusion test method is the additional requirement for video capture. The video capture device should be positioned to ensure that the capture area covers the entire vehicle, including the body, vehicle bottom, and passenger compartment (seats, instruments, floor). The video capture device should cover at least 1.2 m from the front and rear of the vehicle and 0.8 m from the sides of the vehicle. As shown in Figure 2, the video capture device is used to record the presence or absence of phenomena such as smoke, fire, and explosion throughout the entire experimental process, as well as the corresponding times.

[0042] The coverage area of ​​the video capture device installed around the vehicle is determined by referring to the parking space dimensions specified in two industry standards. GA / T 850-2009, "Standards for the Installation of On-Street Parking Spaces on Urban Roads," defines three different types of parking space installation: parallel, vertical, and inclined. JGJ100-2015, "Standards for the Architectural Design of Parking Lots," defines the minimum clearances between vehicles and between vehicles and walls, pillars, and guardrails for different models of parking space installation. Considering currently available passenger cars, SUVs (Sport Utility Vehicles) and MPVs (Multi-Purpose Vehicles), which are typically 5.5 meters long and 2.2 meters wide, JGJ100-2015 determines that a vertical clearance of 1.2 meters and a horizontal clearance of 0.8 meters generally cover the effective distance between the target vehicle and surrounding vehicles or buildings on the actual parking lot surface.

[0043] Step S5: The first temperature sensor arranged in the passenger compartment acquires temperature data on the surface of the contact object in the passenger compartment.

[0044] Specifically, for temperature testing of the surface of contact objects in the passenger compartment, it is necessary to place corresponding temperature sensors in the test vehicle and obtain temperature data of the surface of the contact objects. Corresponding positions include the positions of each seat in the vehicle that mainly correspond to the head, back, buttocks, and feet of the human body, the inside and outside handles of each door, the steering wheel, the seat belt buckle release button, the hazard light button, the window up / down button, the shift member, the center console box, the inside and outside opening of the front cabin, and the inside and outside opening of the trunk.

[0045] Step S6: The gas concentration sensor group collects gas concentration data of the high-temperature exhaust smoke in the passenger compartment, and the second temperature sensor obtains temperature data of the high-temperature exhaust smoke in the passenger compartment, where the high-temperature exhaust smoke contains CO, CO2 and O2. The gas concentration sensor group and the second temperature sensor are both installed at positions corresponding to the air conditioner outlet and the mouth and nose of the human body in the passenger compartment.

[0046] Specifically, in order to prevent high-temperature exhaust smoke in the passenger compartment from causing irreversible damage, poisoning, or suffocation to the human body, corresponding temperature sensors, CO gas sensors, CO2 gas sensors, and O2 gas sensors are placed at the air conditioner outlets (the outlets corresponding to the face position, the outlets corresponding to the foot position, and the outlets corresponding to the window position) and at positions that simulate the human mouth and nose in the passenger compartment.

[0047] Step S7: Compare the temperature data of the surface of the contact object in the passenger compartment, the gas concentration data, and the temperature data of the high-temperature exhaust smoke with their respective safety standards, and evaluate the heat diffusion capacity of the completed test vehicle based on the corresponding comparison results.

[0048] Preferably, the safety standard for surface temperature data of contact objects in the passenger compartment is 48°C.

[0049] Preferably, the safety standard for the CO concentration data is a value that indicates that the CO concentration is 15 mg / m within 15 minutes. 3 or less, or the CO concentration is 420 ppm or less within 10 minutes.

[0050] The safety standard for the CO2 concentration data is 9839 ppm or less within 15 minutes.

[0051] The safety standard for the O2 concentration data is an O2 concentration of 12% or more.

[0052] Preferably, the safety standard of the temperature data of the high-temperature flue gas is 70°C.

[0053] Furthermore, the method comprises: The method further includes step S8, in which the thermography device is positioned within the predetermined coverage area to capture the temperature distribution on the exterior surface of the vehicle under test and the diffusion of smoke and flames after a thermal runaway event, thereby obtaining temperature field data. The thermography device is positioned at the same location as the video capture device.

[0054] Based on the temperature field data, it is possible to determine whether the vehicle under test will cause damage to facilities or personnel in the external environment after thermal runaway. That is, based on the temperature field data and a predetermined coverage area, it is possible to predict to a certain extent the damage and impact on the surrounding environment, facilities, and personnel when the target vehicle actually dissipates heat. For example, it is possible to predict the potential risk that may occur to a vehicle experiencing thermal runaway in a parking space in a parking lot.

[0055] The thermal diffusion test is performed at the complete vehicle level, and the video capture device and thermography are activated to continuously monitor the test process for two hours after triggering thermal runaway in the target cell. This test requires recording not only battery system-related information and test phenomena, but also information related to the entire vehicle and test phenomena during the vehicle test process. Therefore, the method further includes a step of acquiring battery management system messages and complete vehicle messages for the test vehicle after thermal runaway.

[0056] Based on the battery management system message and the completed vehicle message, it is monitored whether an abnormality occurs in the transmission of the first alarm signal of the test vehicle, and the first alarm signal includes temperature abnormality, battery thermal runaway, turn signal lighting, horn honking, door unlocking, etc.

[0057] Furthermore, the method further includes monitoring whether a door handle in the passenger compartment can be unlocked after a thermal runaway based on the video data, and determining whether the vehicle is convenient for occupants to escape or rescue after a thermal runaway.

[0058] Additionally, the method further includes monitoring whether audio, light warning signals, and instrument warnings occur in the vehicle after thermal runaway based on the video data.

[0059] The method further includes recording the time at which thermal runaway is triggered.

[0060] The method further includes recording the time at which thermal runaway occurs in the battery system.

[0061] Rating System: Among the parameters recorded during the test, the instrument display SOC (State of Charge) reflects the actual state of the test sample at the start of the test. Data on the battery pack's internal temperature, battery pack voltage, passenger compartment temperature, and exhaust smoke concentration can be used to capture the relevant data changes of all key features during the thermal diffusion process of the completed vehicle. The Battery Management System (BMS) and completed vehicle message record the vehicle's initial warning signal transmission status, such as whether the vehicle can transmit further warnings such as temperature abnormality, battery thermal runaway, turn signals on, horn sound, or door unlock within a certain time after thermal runaway occurs. The vehicle's audio, light, and instrument warnings can be used to evaluate the actual external manifestation of the warning signal. The time to trigger thermal runaway, the time to battery system thermal runaway, the time to alarm signal transmission, smoke generation (outside the vehicle), smoke generation (in the passenger compartment), and the time to ignition or explosion reflect important test phenomena and the corresponding time nodes during the complete test process. The door unlocking item is primarily used to evaluate whether a vehicle is convenient for occupant escape or rescue after a runaway. It measures whether personnel can easily open the doors from inside the vehicle and escape, and whether firefighters can easily open the doors to rescue stranded personnel. If the battery goes out of control, the vehicle may lose power, making it impossible to unlock the doors or open the hidden door handles. This could prevent personnel from exiting or the doors from being easily opened from the outside, affecting firefighter rescue efforts. Therefore, future improvements are needed to address the issue of doors being unable to be opened after a thermal runaway.

[0062] Specifically, safety standards are examined from two perspectives: the escape and rescue of the driver and passengers in the passenger compartment. Tests and judgments can be made based on whether the surface of objects in the passenger compartment will cause burns to passengers, and whether high-temperature exhaust smoke in the compartment will cause suffocation or poisoning to passengers.

[0063] The temperature protection safety threshold for contact surfaces in the passenger compartment can be determined by reference to the national standard GB / T 18153-2000, "Safety of Machinery - Contactable Surface Temperatures - Ergonomic Data for Determining the Temperature Limit Values ​​of Hot Surfaces." This standard defines the safety threshold for burns caused by continuous human contact with different materials for different durations. For a 1-minute contact, the safety threshold for burns varies from 51°C to 60°C depending on the material. For a 10-minute contact, the safety threshold for burns is standardized to 48°C. Considering the wide range of contactable materials in the passenger compartment and the current standard's definition of a 5-minute escape time, selecting 48°C for the 10-minute condition provides a certain degree of safety redundancy and fully meets the 5-minute escape time, ensuring that passengers will not be burned by any contact surfaces in the passenger compartment.

[0064] Regarding whether high-temperature exhaust fumes in the passenger compartment will cause irreversible damage to the human body or cause poisoning or suffocation of the passengers, from the perspective of temperature, medical literature and popular science literature have been consulted. When the temperature of gas inhaled into the human body exceeds 70°C, it will cause mucosal congestion, bleeding, blisters or tissue necrosis in the trachea and bronchi, leading to death from pulmonary edema. Therefore, it is appropriate to set the temperature safety boundary of high-temperature exhaust fumes at 70°C.

[0065] In addition, safety boundaries are also defined for three typical gases that can affect personnel evacuation and even cause crew poisoning: CO, CO2, and O2. The safety boundary for O2 can be determined by referring to the definition in the Emergency Management Department's Confined Space Work Safety Guidelines Manual. If the oxygen content is less than 12%, personnel's judgment and coordination may be seriously impaired, and respiratory function may be impaired, causing permanent cardiac damage, nausea, and vomiting. Therefore, it is appropriate to set the O2 concentration at 12% or higher.

[0066] For the safety boundaries of CO and CO2, reference can be made to GBZ2.1-2019, "Occupational Exposure Limits for Hazardous Agents in the Workplace, Part 1: Chemical Hazards," and the relevant definitions in the Material Safety Data Sheet (MSDS). The standard defines three levels of human injury for relevant gases over different time periods. Among these, the Permissible Concentration-Time Weighted Average (PC-TWA) is the average permissible exposure concentration over an 8-hour workday, 40-hour workweek. Given the short-term nature of thermal diffusion, the PC-TWA value is of limited significance. The Permissible Concentration-Short Term Exposure Limit (PC-STEL) is the weighted average permissible concentration over a 15-minute exposure period. The Maximum Allowable Concentration (MAC) is the concentration that must not be exceeded at any time or workplace. For CO2, the standard specifies a PC-STEL value of 18,000 mg / m3. 3 Therefore, the safe limit for CO2 is 18,000 mg / m for 15 minutes. 3 This can be defined as not exceeding 9839 ppm when converted using the standard formula.

[0067] Regarding CO, the standard defines PC-STEL and MAC values ​​corresponding to different altitudes above sea level. Considering the widespread use of automobiles, the MAC value corresponding to altitudes above 3000m is selected as the strictest safety boundary, i.e., CO 15mg / m within 15 min. 3 can be required not to exceed

[0068] Another international reference for defining CO safety boundaries is the Acute Exposure Guideline Levels (AEGLs) issued by the U.S. Environmental Protection Agency (EPA). These guidelines also define three levels of harm to the human body: Level 1 refers to a clear numbness, irritation, or apparent asymptomatic or insensible effects on the human body that are non-disruptive, temporary, and reversible upon cessation of contact; Level 2 refers to irreversible or serious, long-term adverse health effects or other effects that impair escape ability; and Level 3 refers to harm to life or health or death. Therefore, using the safety boundary defined by Level 2 as a reference, the CO concentration within 10 minutes of contact can be limited to 420 ppm. This value can be used in conjunction with the CO safety boundary for 15 minutes.

[0069] The present invention has the following technical effects.

[0070] 1) In the present invention, modification standards are set in advance for initial modifications to the battery system so as not to destroy the existing high and low voltage circuit connections and the existing thermal protection structure of the battery system, thereby making it possible to maintain a certain safety state after a thermal runaway of the existing battery system.

[0071] 2) By using a video capture device that meets the specified coverage range to monitor the vehicle test phenomenon after thermal runaway, video data from each angle can be captured comprehensively, thereby improving monitoring accuracy.

[0072] 3) By establishing new safety standards corresponding to the temperature data of the surface of contact objects in the passenger compartment, gas concentration data, and temperature data of high-temperature exhaust smoke, and using more reliable evaluation indicators, the thermal diffusion protection capability of a completed vehicle can be evaluated more accurately and reliably, and a direction for improving vehicle performance can be provided.

[0073] 4) This invention adopts the thermal diffusion test of the complete vehicle, which is closer to the actual situation and more oriented to the actual use of consumers. Considering the complex working conditions and various scenarios in actual applications, it is necessary to formulate a more systematic plan for the thermal diffusion test method and requirements of the complete vehicle, on the one hand, including the component-level requirement that no ignition or explosion occurs within 5 minutes after the alarm signal is sent, and on the other hand, it adds the judgment of the temperature inside the vehicle, smoke emission, etc. in combination with the vehicle product.

[0074] 5) This invention systematically presents test methods and limit value conditions for temperature, smoke emission, etc., and combines them with actual cases for in-depth analysis. On the one hand, it provides the basis and guidelines for actual product testing, and on the other hand, it can effectively support the creation and revision of international regulations and national standards, and also contribute to improving the safety and reliability of verified products.

[0075] Example 2 FIG. 3 shows an example of the internal structure of a computer device, which may be a database. The computer device includes a processor, a memory, an input / output interface (I / O), and a communication interface. The processor, memory, and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface. The processor of the computer device is used to provide calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operating system and the computer program to run on the non-volatile storage medium. The database of the computer device is used to store transactions to be processed. The I / O interface of the computer device is for information exchange between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, the thermal diffusion test method for a completed new energy vehicle shown in Example 1 is realized.

[0076] Those skilled in the art will understand that all or part of the methods described above can be implemented by issuing instructions to relevant hardware via a computer program. The computer program may be stored in a non-volatile computer-readable storage medium and, when executed, may include the flow of each of the method embodiments described above. Any reference to memory, database, or other medium used in each of the embodiments provided herein may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM), external cache memory, etc. The RAM may be of various types, such as, but not limited to, static random access memory (SRAM) or dynamic random access memory (DRAM). The database according to each embodiment provided by the present invention may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a distributed database based on blockchain. The processor according to each embodiment provided by the present invention may be, but is not limited to, a general-purpose processor, a central processor, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc.

[0077] The technical features in the embodiments described above can be combined in any manner, and for the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, combinations of these technical features should be considered to be within the scope described in this specification, provided they are not inconsistent.

[0078] Although the principles and embodiments of the present invention have been described herein using specific examples, the explanations of the above examples are merely intended to aid in understanding the method and gist of the present invention. Furthermore, those skilled in the art may make modifications to the specific embodiments and scope of application based on the concept of the present invention. Therefore, the contents of this specification should not be construed as limiting the present invention.

Claims

1. determining a charging method for a battery system of a test vehicle and adjusting the state of charge of the battery system according to the charging method; If the charging method is external charging, adjust the corresponding SOC to 95% or more of the normal SOC operating range specified by the manufacturer; If the charging method is charging using vehicle energy, adjust the corresponding SOC to 90% or more of a normal operating range specified by the manufacturer; performing an initial modification to the battery system that meets a predetermined modification standard, the predetermined modification standard being intended to maintain the integrity of the normal connections of the high voltage and low voltage circuits of the completed vehicle and the integrity of the existing thermal protection structure; triggering a battery pack in the battery system to cause thermal runaway, recording status information of the battery pack, and monitoring a state change situation of the battery system after the thermal runaway based on the status information, wherein the status information includes an instrument display SOC, a temperature in the battery pack, and a voltage in the battery pack; a step of using a video capture device to capture video of the test vehicle after thermal runaway, acquiring video data, and monitoring the presence and time of occurrence of smoke, ignition, or explosion in the passenger compartment, outside the vehicle, and battery system of the test vehicle based on the video data, wherein the video capture devices are respectively disposed in the passenger compartment, outside the vehicle, and at the battery system of the test vehicle, and the video capture device disposed outside the vehicle satisfies a predetermined coverage range, the predetermined coverage range being 1.2 m from the front and tail of the vehicle, and 0.8 m from both sides of the vehicle body; collecting temperature data of a surface of a contact object in the passenger compartment by a first temperature sensor disposed in the passenger compartment; The gas concentration sensor group collects gas concentration data of the high-temperature exhaust smoke in the passenger compartment, and the second temperature sensor collects temperature data of the high-temperature exhaust smoke in the passenger compartment, and the high-temperature exhaust smoke contains CO, CO ２ and O ２ wherein the gas concentration sensor group and the second temperature sensor are both disposed at positions corresponding to an air conditioner outlet and the mouth and nose of an occupant; comparing the temperature data of the surface of the contact object in the passenger compartment, the gas concentration data, and the temperature data of the high-temperature exhaust smoke with corresponding safety standards, and evaluating the thermal diffusion capability of the completed vehicle based on the comparison results; The safety standard for the surface temperature data of the contact object in the passenger compartment is 48°C; The safety standard for the CO concentration data is a CO concentration of 15 mg / m within 15 min. ３ or less, or the CO concentration is 420 ppm or less within 10 min, The CO ２ The safety standard for concentration data is 9839 ppm or less within 15 minutes. The above O ２ The safety standard for concentration data is O ２ The concentration is 12% or more, The safety standard of the temperature data of the high-temperature exhaust gas is 70°C, and the above steps are performed by a processor.

2. a step of collecting temperature distribution status, smoke diffusion status, and flame diffusion status of the exterior of the test vehicle after thermal runaway using a thermograph arranged within the predetermined coverage area to obtain temperature field data; 2. The thermal diffusion test method for a completed new energy vehicle as claimed in claim 1, further comprising: determining whether the vehicle under test after thermal runaway will cause damage to facilities or personnel in the external environment based on the temperature field data.

3. acquiring a battery management system message and a completed vehicle message of the vehicle under test after the thermal runaway; and monitoring whether an abnormality occurs in the transmission of the first warning signal of the vehicle under test based on the battery management system message and the completed vehicle message; 2. The thermal diffusion testing method for a new energy vehicle as claimed in claim 1, wherein the first warning signal includes abnormal temperature, battery thermal runaway, indicator light on, horn sounding or door unlocking.

4. The thermal diffusion test method for a completed new energy vehicle as claimed in claim 1, further comprising a step of monitoring whether the door handle inside the passenger compartment can be unlocked after thermal runaway based on the video data, and determining whether the vehicle after thermal runaway is suitable for escaping or rescuing the passengers.

5. 2. The thermal diffusion test method for a completed new energy vehicle as claimed in claim 1, further comprising a step of monitoring whether an audible warning signal, an optical warning signal or an instrument warning occurs in the vehicle after thermal runaway based on the video data.

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