CN-121980870-A - Whole electric vehicle fire disaster simulation and hazard analysis method for underground parking garage

CN121980870ACN 121980870 ACN121980870 ACN 121980870ACN-121980870-A

Abstract

The invention relates to the technical field of electric automobile fire simulation and discloses a method for analyzing fire hazard of an electric automobile in an underground parking lot, which comprises the steps of carrying out a thermal runaway test on a power battery unit of the electric automobile to obtain related data, building a three-dimensional geometric model of the underground parking lot and the electric automobile according to the actual structural size, simplifying the automobile body of the electric automobile and reserving combustible parts, carrying out hierarchical modeling on surrounding vehicles by considering the influence of beams and columns, carrying out simulation by Pyrosim software, setting multiple parameters and taking test data as boundary conditions to obtain a result, carrying out multidimensional analysis on the monitoring data after simulation, and constructing an evaluation model by a specific method to quantitatively evaluate fire hazard, thereby solving the technical problems of the conventional simulation multi-focus single automobile scene, and lacking simulation of multi-automobile coupling and large-space fire hazard spreading behaviors.

Inventors

YAN TAO
Ran Chongpu
LIU MING
SU XIAOJIA
ZHAO ZHIWEI
WANG YU
CHENG HAO
DU YOUXING
LI WUXIN
SU HUIQIANG

Assignees

中国汽车工程研究院股份有限公司
中汽院新能源科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. The method for simulating the fire disaster and analyzing the hazard of the whole electric automobile in the underground parking garage is characterized by comprising the following steps: S1, performing a thermal runaway test on a power battery monomer corresponding to an electric automobile to be simulated to obtain thermal physical property parameters and fire burning data of the power battery monomer; S2, building a three-dimensional geometric model of the underground parking garage and the electric vehicle according to the actual structure and the size, simplifying the vehicle body structure and retaining combustible components when the electric vehicle is modeled, and reducing the space structure, key openings and the blocking effect of beam columns on smoke flow when the scene model of the underground parking garage is built; S3, simulating by adopting Pyrosim software, setting material parameters, combustion reaction, grid division, boundary conditions and a physical model, taking fire combustion data obtained by a thermal runaway test as the boundary conditions, and obtaining a simulation result through multi-parameter setting and server calculation; and S4, after the simulation is finished, carrying out multidimensional analysis on the fire evolution process of the electric automobile based on preset monitoring points and slice data, and constructing an evaluation model by adopting a hierarchical analysis method and an expert scoring method through multisource monitoring indexes to realize quantitative evaluation of fire hazard.
2. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage is characterized in that the thermophysical parameters in S1 comprise the size, density, specific heat capacity and heat conductivity of a battery, and the fire combustion data comprise the temperature of monitoring points on the surface of the battery, the pyrolysis gas composition and the gas composition after combustion.
3. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 2, wherein the specific method in S3 comprises the following steps: Setting material parameters and combustion reaction, namely setting the material parameters and combustion reaction of combustible materials according to thermal runaway test data and literature, wherein the combustible materials comprise power batteries, tires, internal decorations and seats, and the material parameters comprise density, specific heat capacity, heat conductivity, radiation coefficient, absorption coefficient, pyrolysis reaction and products; based on Pyrosim built-in buoyancy plume models of software, grid sizes are set according to regional fire disaster characteristics in a differentiated mode: In the core area where the fire is occurring and spreading, it is necessary to encrypt the mesh with a minimum mesh size defined by the characteristic flame diameter Determining the minimum mesh size as the characteristic flame diameter 1/4 To 1/16 of the total number of the components; For the area with smoke spreading and no combustion reaction, the mesh size is increased compared with the core area; the method comprises the steps of constructing a special surface model for each part of the electric automobile, importing corresponding material parameters, defining surface physical characteristics, setting boundary conditions by adopting a characteristic point temperature curve assignment mode aiming at the thermal runaway process of the power battery, namely selecting a power battery unit at the geometric center position of a battery pack at the bottom of the electric automobile, defining the surface type as heater/cooler, assigning a battery thermal runaway surface monitoring point temperature curve acquired from fire combustion data to the surface, and simulating the thermal runaway process of the unit battery.
4. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 3, wherein the step S3 further comprises: using Pyrosim software to simulate the fire combustion process in each control unit after grid division, and solving a multiphase physical field control equation to realize the simulation of the fire combustion process, wherein the core control equation comprises: mass conservation equation: ; Wherein ρ is density, u is velocity vector, and t is time; momentum conservation equation: ; wherein p is pressure, g is gravitational acceleration, and τ is viscous stress tensor; Component conservation equation: ; In the formula, Is the concentration of the i-th component, Is the diffusion coefficient of the i-th component, Is the rate of formation or dissipation of the i-th component per unit volume; Energy conservation equation: ; Wherein, h is specific enthalpy, q ' ' ' is a volumetric heat source, q is a radiant heat flux vector, and phi is a dissipation function; gas state equation: wherein T is the gas temperature, R is the general gas constant, M is the molar molecular weight of the mixed gas, Is the molar molecular weight of component i; Based on the multi-dimensional data monitoring function of Pyrosim software, a dual monitoring system of space field visualization and characteristic point time sequence monitoring is constructed and used for acquiring key physical parameters in fire simulation, and for space field analysis, the distribution conditions of speed, temperature and flue gas concentration parameters are visualized by setting two-dimensional or three-dimensional slices.
5. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 4, wherein the step S3 is characterized in that for time sequence data of a specific position, point type measuring equipment is arranged, and a specific arrangement scheme comprises: triggering temperature monitoring points in a driver cabin of the vehicle to comprise a headrest position, a seat position and a pedal floor position; Triggering the temperature monitoring points of the vehicle body, wherein the temperature monitoring points comprise a front cabin cover, a windshield, an external ceiling, a trunk cover, front and rear door handles and four wheels of the vehicle; adjacent vehicle approach triggering vehicle side body temperature the monitoring points comprise front and rear wheels and front and rear door handles; triggering a gas monitoring point in a passenger cabin of the vehicle to comprise a headrest position; The radiation heat flow monitoring points comprise front door handle positions of the triggering vehicle and front and side horizontal directions 2m and 4m and front door handle positions of adjacent vehicles, wherein the radiation heat flow monitoring points of the triggering vehicle are perpendicular to the direction of the triggering vehicle, and the setting height of the radiation heat flow monitoring points is positioned at the door handle height; the visibility monitoring points comprise positions of the triggering vehicle in the front horizontal direction 2m, the side horizontal direction 5m and the side horizontal direction 10m, the visibility monitoring points of the triggering vehicle are perpendicular to the direction of the triggering vehicle, and the setting height of the visibility monitoring points is 2m away from the ground.
6. The method for simulating and analyzing fire hazards of the electric automobile in the underground parking garage according to claim 5, wherein in the step S4, a time-space change rule of a temperature field, a heat release rate and visibility can be obtained through measuring points and slices arranged inside and outside a passenger cabin, safety of the passenger by a gas environment in the passenger cabin can be judged through concentration change of toxic and harmful gas in the passenger cabin, and secondary heat hazards caused by fire hazards can be identified through surface temperature and radiation heat flow data of adjacent vehicles.
7. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 6, wherein in S4, the specific method for constructing the evaluation model comprises the following steps: Taking fire hazard of an electric automobile in an underground parking lot as a target, taking heat hazard, smoke hazard and emergency rescue as primary indexes, and dividing the primary indexes into secondary indexes; The secondary index under the heat hazard comprises the temperature rise in the vehicle and the heat flow outside the vehicle, wherein the temperature rise in the vehicle is the maximum temperature rise at the positions of the seats and pedals of passengers in the vehicle within 15 minutes after the thermal runaway of the battery The heat flow outside the vehicle is the heat radiation value q at the position with the distance of 2.0m from the vehicle body within 15 minutes after the thermal runaway of the battery occurs; The secondary index under the harm of the smoke comprises the concentration of carbon monoxide and the concentration of the smoke, wherein the concentration of the carbon monoxide is within 15min after the thermal runaway of the battery occurs, and the concentration of the CO at the headrest of the passenger The smoke concentration is 15min after the battery is out of control ; The secondary indexes under emergency rescue comprise the fire development speed and the visibility, wherein the fire development speed is a fire growth coefficient: q is the heat release rate, kW, t is the fire growth time, the heat release rate reaches 1055kW, s, and the visibility is the visibility V at the position 10.0m away from the vehicle body within 15min after the battery is out of control.
8. The method for simulating and analyzing fire hazards of an electric vehicle in an underground parking garage according to claim 7, wherein S4 further comprises: The importance of each index of the same level is compared and assigned by a plurality of experts, a Saaty-9 scale method is adopted, a two-by-two comparison judgment matrix is established, and an average value is obtained after the highest value and the lowest value are removed; Calculating the maximum eigenvalue and the corresponding eigenvector of the judgment matrix, and obtaining the weight of each level of index through normalization; Carrying out consistency test on the weights so as to avoid the influence of subjective factors, if the consistency ratio CR is smaller than 0.1, considering that the weight distribution is reliable and effective, otherwise, readjusting the judgment matrix is needed; And constructing a fire hazard evaluation model of the whole electric automobile of the underground parking garage according to the weights of all levels of indexes and the scoring standards.
9. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 8, wherein the first-level index of the whole electric automobile fire hazard assessment model in the underground parking garage has the weight of 30% of heat hazard and 50% of smoke hazard, and the weight of 20% of emergency rescue; The weights of the secondary indexes are as follows: in-vehicle temperature rise, weight 60%, and scoring standard: less than or equal to 30 ℃ to obtain 100 minutes, wherein the temperature is less than or equal to 30 DEG C The temperature is less than or equal to 60 ℃ and 80 minutes are obtained; 60 ℃ of The temperature is less than or equal to 80 ℃ and 60 minutes are obtained; 80 ℃ to obtain 0 score; the weight of the heat flow outside the vehicle is 40%, and the scoring standard is q is less than or equal to 10kW +. 100 Min, 10 kW% <q≤15kW/ 80 Min, 15 kW% <q≤20kW/ 60 Min, q >20 kW- Obtaining 0 score; the weight of the smoke hazard is 50%, and the smoke hazard comprises two secondary indexes of carbon monoxide concentration and smoke concentration; carbon monoxide concentration, weight 50%, scoring criteria: less than or equal to 100ppm to obtain 100 parts, 100ppm < Less than or equal to 500ppm to obtain 80 parts, 500ppm < Less than or equal to 1200ppm to obtain 60 minutes; 1200ppm, giving a score of 0; the flue gas concentration is weighted by 50 percent, and the scoring standard is as follows: less than or equal to 100ppm to obtain 100 parts, 100ppm < Less than or equal to 500ppm to obtain 80 parts, 500ppm < Less than or equal to 1000ppm to obtain 60 minutes; 1000ppm to give a score of 0; Emergency rescue, wherein the weight is 20%, and the emergency rescue comprises two secondary indexes of fire development speed and visibility; The fire development speed is 50% by weight, the scoring standard is that alpha is less than or equal to 0.00278 to obtain 100 points, 0.00278< alpha is less than or equal to 0.011 to obtain 80 points, 0.011< alpha is less than or equal to 0.044 to obtain 60 points, 0.044< alpha is less than or equal to 0.178 to obtain 40 points, and alpha is more than 0.178 to obtain 0 points; The visibility is 50% of weight, the scoring standard is that V is more than or equal to 10m to obtain 100 points, V is more than or equal to 6m to obtain 80 points, V is more than or equal to 2m to obtain 60 points, and V is less than or equal to 2m to obtain 0 point.
10. The method for simulating and analyzing the fire hazard of the whole electric automobile in the underground parking garage according to claim 9, wherein a weighted summation method is adopted to calculate the score f of each first-level index and the fire hazard assessment score Z of the electric automobile in the underground parking garage; Z= ; f= ; wherein Z is the evaluation score, Is the i-th first-order indicator score, Is the first level index weight of the i th item; the index is the score of the ith secondary index in a certain level index, n is the number of secondary indexes in a certain level index; According to the evaluation score Z, the fire hazard of the whole electric automobile in the underground parking garage can be classified into five grades, and the specific score ranges are as follows: the first level is that the score range corresponding to the evaluation result is Z more than or equal to 90; Second grade, the fraction range is 80-90; third, the fraction is in the interval of Z <80 and more than or equal to 70; Fourth grade, the fraction satisfies that Z is more than or equal to 60 and less than 70; Five-stage score range Z <60.

Description

Whole electric vehicle fire disaster simulation and hazard analysis method for underground parking garage Technical Field The invention relates to the technical field of fire simulation of electric vehicles, in particular to a fire simulation and hazard analysis method for an electric vehicle in an underground parking lot. Background With the rapid development of new energy automobiles, the problem of electric automobile fire caused by thermal runaway of batteries is attracting attention. The underground parking lot is used as a place for intensively parking and charging the electric automobile, and the proportion of fire accidents rises year by year. With the rapid development of the global new energy automobile industry, the electric automobile maintenance amount continuously rises, and the electric automobile fire disaster problem caused by battery thermal runaway is a focus of high attention in the industry. Underground parking lots are important places for intensively parking and charging electric vehicles, and in recent years, the occurrence proportion of fire accidents is in an annual rising situation. The underground parking garage has the semi-closed structural characteristic, the ventilation condition is limited, the evacuation path is relatively limited, and meanwhile, the internal combustible materials and the electrical equipment are densely distributed. These features allow for a significant increase in the risk of fire in the underground parking in the event of an electric car fire. More seriously, the specificity of the underground environment and the high risk and rapid spread of the fire disaster of the electric automobile are interwoven, so that the complex effects of risk superposition and hazard multiplication are formed. Under the effect, fire accidents often lead to more serious consequences, not only cause huge economic loss, but also cause wide influence on the social level. Therefore, the method can scientifically and accurately evaluate the hazard of the electric automobile fire disaster in the underground parking lot, and has important significance in the aspects of deeply identifying potential risks, clearly revealing disaster causing mechanisms and the like. Currently, the evaluation and research of the fire hazard of electric vehicles in underground parking lots is still in a development stage. In the aspect of evaluating the model, most of the existing models are simplified, dynamic coupling and interaction influence among multiple source risks cannot be fully considered, and multidimensional key elements such as passenger safety guarantee, environmental protection measures, emergency rescue actions and the like are not integrated by the system. The limitation makes the evaluation result difficult to comprehensively reflect the actual situation, and severely restricts the formulation and implementation of the accurate prevention and control strategy. Disclosure of Invention The invention aims to provide a fire disaster simulation and hazard analysis method for an electric automobile in an underground parking lot, which aims to solve the technical problems that the existing simulation multi-focus single automobile scene lacks simulation of multi-automobile coupling and large-space fire disaster spreading behaviors. In order to achieve the aim, the invention adopts the following technical scheme that the fire disaster simulation and hazard analysis method for the whole electric automobile in the underground parking garage comprises the following steps: S1, performing a thermal runaway test on a power battery monomer corresponding to an electric automobile to be simulated to obtain thermal physical property parameters and fire burning data of the power battery monomer; S2, building a three-dimensional geometric model of the underground parking garage and the electric vehicle according to the actual structure and the size, simplifying the vehicle body structure and retaining combustible components when the electric vehicle is modeled, and reducing the space structure, key openings and the blocking effect of beam columns on smoke flow when the scene model of the underground parking garage is built; S3, simulating by adopting Pyrosim software, setting material parameters, combustion reaction, grid division, boundary conditions and a physical model, taking fire combustion data obtained by a thermal runaway test as the boundary conditions, and obtaining a simulation result through multi-parameter setting and server calculation; and S4, after the simulation is finished, carrying out multidimensional analysis on the fire evolution process of the electric automobile based on preset monitoring points and slice data, and constructing an evaluation model by adopting a hierarchical analysis method and an expert scoring method through multisource monitoring indexes to realize quantitative evaluation of fire hazard. The principle and the advantages of the scheme are that based on measured dat