Quantitative evaluation system and method for thermal runaway fire isolation effect of electric vehicle

Abstract

The invention discloses a quantitative evaluation system and method for an electric vehicle thermal runaway fire isolation effect, and belongs to the technical field of electric vehicle fire safety. The system comprises a full-size test platform, a thermal radiation flux meter array, a temperature and voltage acquisition system and a data processing device, the method comprises the following steps: acquiring data through a thermal radiation flux meter array, constructing an evaluation matrix, determining each index weight based on an entropy evaluation method, establishing an isolation effect evaluation function TFA, and realizing quantitative evaluation of different isolation treatment technologies. The method solves the problems of single monitoring point, qualitative evaluation method, lack of quantitative comparison means and the like in the prior art, and has the advantages of scientific evaluation, high applicability, visual result and the like.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle thermal runaway fire safety handling technology, and relates to a quantitative evaluation system and method for the isolation effect of electric vehicle thermal runaway fire. Background Technology

[0002] Electric vehicle (EV) thermal runaway fires develop rapidly, generating large jet fire momentum and causing significant damage, highlighting increasingly prominent safety issues and posing a huge threat to people's lives, property, and safety. EV battery thermal runaway is the most dangerous mode of EV fire. Current research on EV battery thermal runaway fires focuses more on preventing the ignition of surrounding normal EVs, isolating the burning EV, and blocking the fire's spread. Existing research on evaluating the isolation effectiveness of EV fire suppression technologies has the following shortcomings: 1) The individual battery cells experiencing thermal runaway in the EV battery box are random. If characteristic parameters of EV thermal runaway fires, such as flame thermal radiation and temperature, are monitored at a single fixed point, it cannot comprehensively and systematically characterize the fire hazards of EVs. 2) The isolation effectiveness of different EV fire suppression technologies is comprehensively affected by factors such as release method, deployment method, and duration of action; a quantitative evaluation method for isolation effectiveness is lacking. 3) Commonly used fire suppression technologies such as fire blankets, fine water mist (curtains), and foam can suppress fire development through both physical isolation (oxygen extinguishing) and chemical extinguishing, but quantitative evaluation of the isolation effectiveness of different extinguishing technologies is still lacking. Summary of the Invention

[0003] The technical solution of this invention is used to solve the problem of quantitative evaluation of the fire isolation effect of electric vehicles under overcharging conditions.

[0004] The present invention solves the above-mentioned technical problems through the following technical solutions: A quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles includes: a full-size thermal runaway fire test platform for electric vehicles and a temperature and voltage acquisition system for the electric vehicle battery box; the full-size thermal runaway fire test platform for electric vehicles includes: an electric vehicle, a canopy, a release nozzle, a sealed tank, a camera acquisition device, a thermal radiation flux meter, and a data acquisition computer; the temperature and voltage acquisition system for the electric vehicle battery box includes: multiple K-type thermocouples, multiple voltmeters, and a DC adjustable charger; The electric vehicle is parked within the parking space lines below the carport. Release nozzles are installed on the top of the carport and on the ground above the parking space, and these nozzles are connected to a sealed tank via delivery pipelines. Cameras are installed on the upper side of the electric vehicle and behind the battery box. Multiple thermal flux meters employ an n×... The array is deployed on the side of the electric vehicle, maintaining a certain distance from the side of the electric vehicle, n. Take integers greater than or equal to 3 respectively; thermal radiation flux data collected by multiple thermal radiation flux meters are transmitted to the data acquisition computer via data cable; Multiple K-type thermocouples are respectively fixed on multiple battery modules inside the power battery box to measure the temperature of the battery modules; multiple voltmeters are respectively connected to multiple battery modules to collect the voltage value of each battery module and record the voltage change of the battery module before and after thermal runaway; the DC adjustable charger is connected to the charging interface of the power battery box to charge the power battery box until thermal runaway.

[0005] Furthermore, the thermal radiation flux meter in the nth row and 1st column from top to bottom is installed in the middle between the bottom of the electric vehicle and the ground, close to the front tire, and the thermal radiation flux meter in the 1st row and 1st column from top to bottom is installed next to the A-pillar of the electric vehicle.

[0006] Furthermore, the lateral distance of each column of the thermal radiation flux meters The overall length L of the power battery pack of the electric vehicle and ( The ratio of -1), i.e. =L / ( -1).

[0007] Furthermore, the voltmeter is a high-impedance voltmeter.

[0008] A quantitative evaluation method for a quantitative evaluation system based on the isolation effect of thermal runaway fires in electric vehicles includes the following steps: S1. Select electric vehicles with the same battery capacity and conduct a full-scale overcharge fire experiment to obtain the thermal radiation flux of the fire. The curve of heat radiation flux changing with time t; define two stages of heat radiation flux change with time, namely: the two stages before and after the application of fire isolation treatment technology, and successively remove the heat radiation flux data of heat radiation flux meters at different locations before the application of isolation treatment technology; S2. Based on the image information acquired by the camera acquisition device, the temperature data monitored by the K-type thermocouple, and the voltage data of each battery module in the power battery box acquired by the voltmeter, determine the application time t of the electric vehicle fire isolation and treatment technology. e This leads to the determination that the thermal radiation flux exceeds the critical thermal radiation flux. Cumulative action time ; S3, n× Thermal radiation flux collected by thermal radiation flux meters at different locations after the application of isolation treatment technology. Sequentially at the time t of application e Integrate within the range to obtain the heat radiation value per unit area of ​​the flame at different locations. , Based on n× Based on the measurements of a thermal flux meter, the total thermal radiation heat of an electric vehicle fire is constructed. Evaluation model, Where S is the area of ​​the side of the electric vehicle frame. The value of heat radiation per unit area of ​​the flame collected by the i-th thermal radiation meter; S4. Conduct fire tests on electric vehicles using m different fire isolation and treatment technologies, and establish an evaluation set U={ of the fire isolation and treatment technologies. , K}, constructing a system containing total thermal radiation energy Cumulative action time The evaluation matrix A = {U1, U2, U3, ..., U...} is used to evaluate three indicators: the rate of thermal runaway in the power battery module, K, and so on. m}, where U1, U2, U3, ..., U m U is the evaluation set for the fire isolation effectiveness of electric vehicles under isolation technologies 1 to m. m ={ , , }; S5, to eliminate thermal radiation energy Cumulative action time The impact of three characteristic parameters—the rate K of thermal runaway in the electric vehicle power battery box—with different dimensions is investigated. The evaluation matrix A is standardized to construct a standardized matrix E. The sample value in the i-th row and j-th column of the standardized matrix E is then determined. The expression, i.e. ,in, To evaluate the sample value in the i-th row and j-th column of matrix A, To evaluate the maximum value of the sample in the j-th column of matrix A, To evaluate the minimum value of the sample in the j-th column of matrix A; S6, Quantification of thermal radiation energy Cumulative action time The contribution of three characteristic parameters—K (the rate of thermal runaway in the electric vehicle's power battery box)—to the total thermal radiation heat in an electric vehicle fire. , , ; Calculate the optimal value of the evaluation index for each isolation treatment technology applied. worst value A thermal radiation assessment function (TFA) for electric vehicle thermal runaway fires under overcharging conditions is constructed based on a comprehensive weighted distance.

[0009] Furthermore, the determined thermal radiation flux value exceeds the critical thermal radiation flux. Cumulative action time The method is as follows: Based on the heat radiation flux of the fire The curve of change with time t, for Greater than or equal to The time is accumulated and summed, and n× The maximum critical exposure time among the individual thermal radiometers is the cumulative exposure time in the thermal radiation assessment set. ,Right now ,in, The thermal radiation flux collected by the Nth thermal radiometer greater than critical heat flux time, for The Nth radiometer in the thermal radiation array.

[0010] Furthermore, the quantified thermal radiation energy Cumulative action time The contribution of three characteristic parameters—K, the rate of thermal runaway in the electric vehicle power battery pack module, to the fire isolation effect of electric vehicles. , , The specific method is as follows: 1) The weights of evaluation index j under the i-th isolation and treatment technology in evaluation matrix A. The calculation formula is as follows:

[0011] 2) Based on weight Determine the entropy value of the j-th evaluation indicator. The calculation formula is as follows:

[0012] 3) Based on weight Determine the contribution level of the j-th evaluation indicator. The calculation formula is as follows:

[0013] in, This refers to the number of types of isolation and treatment technologies.

[0014] Furthermore, the optimal value corresponding to the j-th evaluation index under each isolation and treatment technology is calculated. worst value The calculation formula is as follows:

[0015]

[0016] in, Apply the optimal value corresponding to the j-th evaluation index to the m-th isolation technique. Apply the worst-case value corresponding to the j-th evaluation index to the m-th isolation technique.

[0017] Furthermore, the calculation formula for the thermal radiation assessment function (TFA) of electric vehicle thermal runaway fire under overcharge conditions is as follows:

[0018] Where i and j are natural numbers greater than 0. , , Let be the value in the i-th row and j-th column of the standard matrix E.

[0019] Furthermore, the isolation technology employs one of compressed air foam technology, fine water mist technology, or fire blanket technology, or a combination of two of the three.

[0020] The beneficial effects of this invention are as follows: This invention achieves comprehensive monitoring of the spatial distribution of fire heat radiation through the arrangement of a thermal radiation flux meter array; it constructs a multi-index evaluation matrix and a standardized processing flow to achieve quantitative evaluation of isolation effects; it uses the entropy method to determine the weight of each index, improving the scientific nature and objectivity of the evaluation results; it is applicable to the comparison of the effects of various isolation technologies (such as fire blankets, fine water mist, foam, etc.); the evaluation results are intuitive and can provide a scientific basis for the selection and application of fire isolation technologies for electric vehicles. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structural composition of the full-size thermal runaway fire test platform of the quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles according to Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the structure of the electric vehicle battery box temperature and voltage acquisition system of the quantitative evaluation system for the isolation effect of electric vehicle thermal runaway fire in Embodiment 1 of the present invention. Figure 3 This is a flowchart of a quantitative evaluation method for the isolation effect of electric vehicle thermal runaway fire according to Embodiment 2 of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments: Example 1 This embodiment provides a quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles, including: a full-size thermal runaway fire test platform for electric vehicles and a temperature and voltage acquisition system for electric vehicle battery boxes.

[0024] like Figure 1 As shown, the full-size thermal runaway fire test platform for electric vehicles includes: an electric vehicle 1, a canopy 2, release nozzles 3, a sealed tank 4, a camera acquisition device 5, a thermal radiation flux meter 6, and a data acquisition computer 7. The electric vehicle 1 is parked within the parking space lines below the canopy 2. Release nozzles 3 are installed on the top of the canopy 2 above the parking space and on the ground. The release nozzles 3 are connected to the sealed tank 4 via delivery pipelines. The sealed tank 4 stores liquid extinguishing medium. Camera acquisition devices 5 are installed on the upper side of the electric vehicle 1 and behind the battery box. Camera acquisition devices 5 are also installed behind the battery box. Figure 1 Not shown in the diagram; multiple thermal radiation flux meters 6 employ n× (n, The thermal flux meters 6 (each a number greater than or equal to 3) are arranged in an array on the side of electric vehicle 1, maintaining a certain distance from the side of electric vehicle 1; the thermal flux meter 6 in the nth row and 1st column from top to bottom is installed in the middle between the bottom of electric vehicle 1 and the ground, close to the front tire; the thermal flux meter 6 in the 1st row and 1st column from top to bottom is installed next to the A-pillar of electric vehicle 1; the lateral distance of each column of thermal flux meters 6 is... The overall length L of the power battery box of electric vehicle 1 is ( The ratio of -1), i.e. =L / ( -1), the thermal radiation flux data collected by multiple thermal radiation flux meters 6 are transmitted to the data acquisition computer 7 via data cable.

[0025] like Figure 2As shown, the electric vehicle battery box temperature and voltage acquisition system includes: multiple K-type thermocouples 11, multiple voltmeters 12, and a DC adjustable charger 13; the multiple K-type thermocouples 11 are respectively fixed on multiple battery modules inside the power battery box for measuring the temperature of the battery modules; the multiple voltmeters 12 are respectively connected to multiple battery modules for acquiring the voltage value of each battery module and recording the voltage change of the battery module before and after thermal runaway; preferably, the voltmeters 12 are high-impedance voltmeters; the DC adjustable charger 13 is connected to the charging interface of the power battery box for charging the power battery box until thermal runaway.

[0026] Example 2 like Figure 3 As shown in the figure, this embodiment discloses a quantitative evaluation method for the isolation effect of thermal runaway fires in electric vehicles, including: Step 1: Select a thermal radiation flux meter with the same range, and deploy n× [meters] at the rear side of the vehicle based on the electric vehicle's size information and the location of the power battery pack. (n≥3, ≥3) thermal radiation flux meters are used to monitor and record the ambient thermal radiation flux Q under the overcharging condition of electric vehicles. f The thermal radiation flux meter adopts an n×n * The thermal radiation meters are deployed in an array. The position of the thermal radiation meter in the nth row and 1st column from top to bottom is placed in the middle between the bottom of the test electric vehicle and the ground, close to the front tire. The position of the thermal radiation meter in the 1st row and 1st column from top to bottom is placed next to the A-pillar. The lateral distance between each column of thermal radiation flux meters is... It is approximately the ratio of the overall length L of the power battery pack to (n-1), that is... =L / ( -1), the thermal radiation flux collected by the thermal radiation flux meter is transmitted to the data acquisition computer; electric vehicles with the same battery capacity are selected to conduct a full-scale overcharge fire experiment. The overcharge equipment uses a 120A / 120V DC adjustable charger to obtain the thermal radiation flux of the fire. Changes over time t ~t; Define two stages of the change of thermal radiation flux over time, namely: the two stages before and after the application of fire isolation and treatment technology, and sequentially remove the thermal radiation flux data of thermal radiation flux meters at different locations before the application of isolation and treatment technology.

[0027] Step 2: Conduct a full-scale electric vehicle overcharge thermal runaway test. Place a camera on the upper side of the test electric vehicle and at the rear of its chassis to monitor the evolution of the thermal runaway fire in the power battery box. Use K-type armored thermocouples with a range of 0-1000℃. Deploy one K-type thermocouple at the center of the side of each battery module inside the power battery box to determine the temperature change during overcharge thermal runaway. Use a high-impedance voltmeter to monitor the voltage change of each battery module in the power battery box during overcharge. Combine this with the thermocouple temperature changes to determine the rate K of thermal runaway in the power battery box. Based on the image information captured by the cameras, the temperature data monitored by the thermocouples, and the voltage data collected from each battery module in the power battery box, determine the application time of the electric vehicle fire isolation and treatment technology. Further, it was determined that the thermal radiation flux exceeded the critical thermal radiation flux. Cumulative action time Critical thermal radiation flux The critical thermal flux can be determined by the cone test of the electric vehicle frame. The minimum thermal flux required for the interior trim to ignite on one side of the frame, observed from the cone test, is the critical thermal flux. The thermal flux of the fire... The curve of change with time t, for Greater than or equal to The time is accumulated and summed, and n× The maximum critical exposure time among the individual thermal radiometers is the cumulative exposure time in the thermal radiation assessment set. ,Right now ,in, The thermal radiation flux collected by the Nth thermal radiometer greater than critical heat flux time, for The Nth radiometer in the thermal radiation array.

[0028] Step 3, convert n× Thermal radiation flux collected by thermal radiation flux meters at different locations after the application of isolation treatment technology. The relationship between the change and time t can be obtained through mathematical fitting. Based on the mathematical fitting formula, the area integral is performed within the time of the isolation and treatment measures to obtain the heat radiation value per unit area of ​​the flame at different locations. Based on n× Each thermal radiation flux meter measurement, based on n× Based on the measurements of a thermal flux meter, a model for assessing the total thermal radiation heat in an electric vehicle fire is constructed. Where S is the area of ​​the side of the electric vehicle frame. This represents the heat radiation value per unit area of ​​the flame collected by the i-th thermal radiation meter.

[0029] Step 4: Conduct fire tests on electric vehicles using m different fire isolation and treatment technologies, and establish a thermal radiation assessment set U={ , K}, constructing a system containing total thermal radiation energy Cumulative action time The evaluation matrix A for the three evaluation indicators—the rate of thermal runaway in the power battery module, K, and others—is as follows:

[0030] Among them, U1, U2, U3, ..., U m U is the evaluation set for the fire isolation effectiveness of electric vehicles under isolation technologies 1 to m. m ={ , , }

[0031] The isolation and treatment technology can be one of compressed air foam technology, fine water mist technology, or fire blanket technology, or a combination of two of the three technologies.

[0032] Step 5: To eliminate thermal radiation energy Cumulative action time The impact of three characteristic parameters—the rate of thermal runaway in the electric vehicle power battery module, and their different dimensions—is investigated. The evaluation matrix A is standardized to construct a standardized matrix E, namely:

[0033] In the formula, m represents the number of isolation technologies compared in electric vehicle fires.

[0034] Sample values ​​in the i-th row and j-th column of the standard matrix E expression ,in To evaluate the sample value in the i-th row and j-th column of matrix A, To evaluate the maximum value of the sample in the j-th column of matrix A, To evaluate the minimum value of the sample in the j-th column of matrix A.

[0035] Step 6: Quantify thermal radiation energy Cumulative action time The contribution of three characteristic parameters—the rate of thermal runaway in the electric vehicle's power battery module (K)—to the fire isolation effect of electric vehicles is as follows: , , It can be determined using the entropy method: (1) The weight of evaluation index j under the i-th isolation treatment technology in evaluation matrix A :

[0036] (2) Further based on weights Determine the entropy value of the j-th evaluation indicator. :

[0037] (3) Further based on weight Determine the contribution level of the j-th evaluation indicator. :

[0038] In the formula, Let represent the sample value in the i-th row and j-th column of the evaluation matrix A, and m represent the number of types of isolation and treatment technologies compared in electric vehicle fires.

[0039] Calculate the optimal value for a specific indicator under each isolation and treatment technique. worst value :

[0040]

[0041] in, Apply the optimal value corresponding to the j-th evaluation index to the m-th isolation technique. Apply the worst-case value corresponding to the j-th evaluation index to the m-th isolation technique.

[0042] Furthermore, an evaluation function TFA (Thermal Radiation Assessment) is constructed based on a comprehensive weighted distance to assess the isolation effectiveness of electric vehicles under overcharging conditions in the event of thermal runaway fire.

[0043] In the formula, i and j are natural numbers greater than 0. , , Let be the value in the i-th row and j-th column of the standard matrix E.

[0044] This invention is based on a full-scale test of an electric vehicle overcharge thermal runaway fire to obtain the thermal radiation flux of the fire. The t-curve over time, and the application time of fire isolation and treatment technologies. The thermal radiation flux value exceeds the critical thermal radiation flux. Cumulative action time Assess the total thermal radiation heat of electric vehicle fires Constructing a system containing total thermal radiation energy Cumulative action time An evaluation matrix A is used to assess three evaluation indicators: the rate of thermal runaway in the electric vehicle power battery module (K). This matrix quantifies the contribution of these three indicators to the fire isolation effectiveness of electric vehicles, in descending order of importance. , , Calculate the optimal value for a specific indicator under each isolation and treatment technique. worst value A comprehensive weighted distance is used to construct a thermal runaway fire isolation effect evaluation function (TFA) for electric vehicles under overcharge conditions. By comparing the magnitude of the TFA values, the isolation effect of different isolation treatment technologies for thermal runaway fires of electric vehicles under overcharge conditions can be quantitatively evaluated.

[0045] Example 3 An electronic device includes a memory and a processor, the memory being used to store a program that supports the processor in executing a quantitative evaluation method for the isolation effect of thermal runaway fires in electric vehicles according to Embodiment 2, the processor being configured to execute the program stored in the memory.

[0046] Example 4 A storage medium storing a computer program, which, when executed by a processor, performs the steps of the quantitative evaluation method for the isolation effect of thermal runaway fires in electric vehicles as described in Embodiment 2.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles, characterized in that, include: A full-scale thermal runaway fire test platform for electric vehicles and a temperature and voltage acquisition system for electric vehicle battery boxes; The full-size thermal runaway fire test platform for electric vehicles includes: an electric vehicle (1), a canopy (2), a release nozzle (3), a sealed tank (4), a camera acquisition device (5), a thermal radiation flux meter (6), and a data acquisition computer (7); the electric vehicle battery box temperature and voltage acquisition system includes: multiple K-type thermocouples (11), multiple voltmeters (12), and a DC adjustable charger (13). The electric vehicle (1) is parked within the parking space lines below the carport (2). Release nozzles (3) are installed on the top of the carport (2) and on the ground above the parking space. The release nozzles (3) are connected to the sealed tank (4) via a delivery pipeline. Camera acquisition devices (5) are installed on the upper side of the electric vehicle (1) and behind the battery box. Multiple thermal flux meters (6) employ n× The array is deployed on the side of the electric vehicle (1) and maintains a certain distance from the side of the electric vehicle (1), n, Take integers greater than or equal to 3 respectively; the thermal radiation flux data collected by multiple thermal radiation flux meters (6) are transmitted to the data acquisition computer (7) via data cable; Multiple K-type thermocouples (11) are fixed on multiple battery modules inside the power battery box to measure the temperature of the battery modules; multiple voltmeters (12) are connected to multiple battery modules to collect the voltage value of each battery module and record the voltage change of the battery module before and after thermal runaway; the DC adjustable charger (13) is connected to the charging interface of the power battery box to charge the power battery box until thermal runaway.

2. The quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles according to claim 1, characterized in that, The thermal radiation flux meter (6) in the nth row and 1st column from top to bottom is installed in the middle position between the bottom of the electric vehicle (1) and the ground and close to the front tire. The thermal radiation flux meter (6) in the 1st row and 1st column from top to bottom is installed next to the A-pillar of the electric vehicle (1).

3. The quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles according to claim 1, characterized in that, Lateral distance of each column of the thermal radiation flux meter (6) The overall length L of the power battery box of electric vehicle (1) is related to ( The ratio of -1), i.e. =L / ( -1).

4. The quantitative evaluation system for the isolation effect of thermal runaway fires in electric vehicles according to claim 1, characterized in that, The voltmeter (12) is a high-impedance voltmeter.

5. A quantitative evaluation method for a quantitative evaluation system based on the thermal runaway fire isolation effect of an electric vehicle according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Select electric vehicles with the same battery capacity and conduct a full-scale overcharge fire experiment to obtain the heat radiation flux of the fire. The curve of heat radiation flux changing with time t; define two stages of heat radiation flux change with time, namely: the two stages before and after the application of fire isolation treatment technology, and successively remove the heat radiation flux data of heat radiation flux meters at different locations before the application of isolation treatment technology; S2. Based on the image information acquired by the camera acquisition device, the temperature data monitored by the K-type thermocouple, and the voltage data of each battery module in the power battery box acquired by the voltmeter, determine the application time t of the electric vehicle fire isolation and treatment technology. e This leads to the determination that the thermal radiation flux exceeds the critical thermal radiation flux. Cumulative action time ; S3, n× Thermal radiation flux collected by thermal radiation flux meters at different locations after the application of isolation treatment technology. Sequentially at the time t of application e Integrate within the range to obtain the heat radiation value per unit area of ​​the flame at different locations. , Based on n× Based on the measurements of a thermal flux meter, the total thermal radiation heat of an electric vehicle fire is constructed. Evaluation model, Where S is the area of ​​the side of the electric vehicle frame. The value of heat radiation per unit area of ​​the flame collected by the i-th thermal radiation meter; S4. Conduct fire tests on electric vehicles using m different fire isolation and treatment technologies, and establish an evaluation set U={ of the fire isolation and treatment technologies. , K}, constructing a system containing total thermal radiation energy Cumulative action time The evaluation matrix A = {U1, U2, U3, ..., U...} is used to evaluate three indicators: the rate of thermal runaway in the power battery module, K, and so on. m }, where U1, U2, U3, ..., U m U is the evaluation set for the fire isolation effectiveness of electric vehicles under isolation technologies 1 to m. m ={ , , }; S5, to eliminate thermal radiation energy Cumulative action time The impact of three characteristic parameters—the rate K of thermal runaway in the electric vehicle power battery box—with different dimensions is investigated. The evaluation matrix A is standardized to construct a standardized matrix E. The sample value in the i-th row and j-th column of the standardized matrix E is then determined. The expression, i.e. ,in, To evaluate the sample value in the i-th row and j-th column of matrix A, To evaluate the maximum value of the sample in the j-th column of matrix A, To evaluate the minimum value of the sample in the j-th column of matrix A; S6, Quantification of thermal radiation energy Cumulative action time The contribution of three characteristic parameters—K (the rate of thermal runaway in the electric vehicle's power battery box)—to the total thermal radiation heat in an electric vehicle fire. , , ; Calculate the optimal value of the evaluation index for each isolation treatment technology applied. worst value A thermal radiation assessment function (TFA) for electric vehicle thermal runaway fires under overcharging conditions is constructed based on a comprehensive weighted distance.

6. The quantitative assessment method according to claim 5, characterized in that, The determined thermal radiation flux value exceeds the critical thermal radiation flux. Cumulative action time The method is as follows: Based on the heat radiation flux of the fire The curve of change with time t, for Greater than or equal to The time is accumulated and summed, and n× The maximum critical exposure time among the individual thermal radiometers is the cumulative exposure time in the thermal radiation assessment set. ,Right now ,in, The thermal radiation flux collected by the Nth thermal radiometer greater than critical heat flux time, for The Nth radiometer in the thermal radiation array.

7. The quantitative assessment method according to claim 5, characterized in that, The quantified thermal radiation energy Cumulative action time The contribution of three characteristic parameters—the rate of thermal runaway in the electric vehicle power battery pack module (K)—to the fire isolation effect of electric vehicles. , , The specific method is as follows: 1) The weights of evaluation index j under the i-th isolation and treatment technology in evaluation matrix A. The calculation formula is as follows: 2) Based on weight Determine the entropy value of the j-th evaluation indicator. The calculation formula is as follows: 3) Based on weight Determine the contribution level of the j-th evaluation indicator. The calculation formula is as follows: in, This refers to the number of types of isolation and treatment technologies.

8. The quantitative assessment method according to claim 7, characterized in that, Calculate the optimal value of the j-th evaluation index under each isolation treatment technique. worst value The calculation formula is as follows: in, Apply the optimal value corresponding to the j-th evaluation index to the m-th isolation technique. Apply the worst-case value corresponding to the j-th evaluation index to the m-th isolation technique.

9. The quantitative assessment method according to claim 8, characterized in that, The calculation formula for the thermal radiation assessment function (TFA) of electric vehicle thermal runaway fire under overcharge conditions is as follows: Where i and j are natural numbers greater than 0. , , This represents the value in the i-th row and j-th column of the standard matrix E.

10. The quantitative assessment method according to claim 5, characterized in that, The isolation technology employs one of the following: compressed air foam technology, fine water mist technology, or fire blanket technology, or a combination of two of the three.

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