CN117970145A - A lithium battery thermal runaway simulation test device and test method - Google Patents

Abstract

The present application discloses a lithium battery thermal runaway simulation test device and test method, the test device comprising: a test chamber, a liquid injection system, a gas injection system, an inerting agent injection system, a pressure sensor, a temperature sensor, and a data acquisition system. The test device of the present application can simulate multiple scenarios for thermal runaway of lithium batteries, test multiple eruptions such as gas, liquid, and solid separately or in combination, and evaluate their hazard levels, providing an important reference for the safe use of lithium batteries and fire protection.

Description

A lithium battery thermal runaway simulation test device and test method

Technical Field

The present application belongs to the field of power battery safety technology, and specifically relates to a lithium battery thermal runaway simulation test device and test method.

Background technique

With the increasing shortage of petrochemical energy in the world, various fields are gradually turning to new energy. In the fields of transportation and energy storage, large-capacity lithium iron phosphate batteries are widely used due to their high energy density and long cycle life. However, puncture, overheating, overcharging, and short circuits can cause thermal runaway of lithium iron phosphate batteries, leading to fire and combustion. After the battery thermal runaway, due to a large number of irreversible chemical reactions, its internal air pressure will rise rapidly and the safety valve will open. The combustible mixture will erupt to the outside, causing safety problems.

The mixture of battery thermal runaway is mainly a gas-liquid two-phase mixture. The combustible mixed gas is mainly composed of battery release gases such as hydrogen, methane, carbon monoxide, and ethylene, and carbon monoxide is extremely toxic to the human body. The liquid is mainly an electrolyte, and the common electrolyte is a mixture of ethylene dimethyl carbonate (EC) and dimethylpropylene carbonate (DMC). The gas-liquid two-phase eruption material erupts into the air and burns, and is toxic. There is still little research on its safety assessment.

Among the existing patents, CN109946634A with the IPC main classification number of G01R discloses a method and device for simulating the thermal runaway environment of lithium batteries, which uses a closed box to simulate the lithium-ion battery box, installs a gas collection chamber at the bottom of the box, and automatically configures the gas composition and gas production of the gas sprayed when the battery thermal runaway occurs into a mixed gas in the gas collection chamber and heats it through the control system, and then quickly injects the mixed gas into the box to simulate the environmental state and changes of the gas and temperature in the battery box when a single battery in the lithium-ion battery box thermally runs away. However, it only considers the gas composition, and does not consider the influence of the electrolyte composition and inert agent.

In view of the problems existing in the prior art, there is an urgent need for a lithium battery thermal runaway simulation test device and test method to improve the safety of lithium batteries after thermal runaway eruption and provide a theoretical reference for fire fighting and fire extinguishing.

The above information disclosed in the background technology is only used to increase the understanding of the background technology of the present application, and therefore, it may include information that does not constitute the prior art known to ordinary technicians in the field.

Summary of the invention

In order to overcome the above problems existing in the prior art, the present application provides a lithium battery thermal runaway simulation test device and test method. In the test device, a single-phase or multi-phase ejection combustion test can be performed in a designed test chamber, and the safety index evaluation is performed using the assignment and product scaling method, providing a reference for the safe use of lithium batteries and fire protection.

In some embodiments of the present application, a lithium battery thermal runaway simulation test device is provided, comprising:

A test chamber, the test chamber comprising a chamber body, wherein a nozzle, a bracket, and a spark plug are arranged in the chamber body; the nozzle is located at the bottom of the test chamber, the spark plug is arranged on the bracket located above the nozzle, and the bracket is fixed in the test chamber;

A liquid injection system, comprising a liquid storage tank, a first pump body, a first turbine flowmeter, a first valve and a first flow valve which are sequentially connected through a liquid pipeline;

A gas injection system, comprising a gas storage tank, a gas bag, a second pump body, a second turbine flowmeter, a third valve and a second flow valve which are sequentially connected via a gas pipeline;

An inerting agent injection system, comprising an inerting agent storage tank, a third pump body, a third turbine flowmeter, a fourth valve and a third flow valve which are sequentially connected via an inerting agent transmission pipeline;

A pressure sensor, used to obtain pressure information in the test chamber;

Temperature sensor, used to obtain temperature information in the test chamber;

The data acquisition system includes a data acquisition instrument and a computer. The data acquisition instrument is electrically connected to the pressure sensor and the temperature sensor to collect pressure and temperature information in the test chamber. The computer is used to process the pressure and temperature data collected by the data acquisition instrument.

The liquid pipeline, gas pipeline, and inerting agent transmission pipeline are all connected to one end of the mixture pipeline, and the other end of the mixture pipeline is connected to the nozzle at the bottom of the test chamber. The mixed gas is transported to the nozzle at the bottom of the test chamber through the mixture pipeline, sprayed into the test chamber by the nozzle, and ignited by the spark plug for testing.

In some embodiments of the present application, a second valve is provided on the mixture pipeline.

In some embodiments of the present application, the first valve, the second valve, the third valve, and the fourth valve are used to control the on-off of the pipeline; and are used to control the opening size of the flow valve in the pipeline according to the numerical values of the first turbine flowmeter, the second turbine flowmeter, and the third turbine flowmeter.

In some embodiments of the present application, the test chamber is an insulated container.

In some embodiments of the present application, the nozzle is in the shape of an inverted umbrella.

In some embodiments of the present application, there are multiple gas storage tanks, and the multiple gas storage tanks respectively store battery-released gases such as hydrogen, methane, carbon monoxide, ethylene and acetylene.

In some embodiments of the present application, the gas is modulated according to the ratio of gas released by the thermal runaway of the lithium iron phosphate battery and then flushed into the air bag for standby use.

In some embodiments of the present application, the nozzle is connected to the fourth pump body through a fifth valve. When the test is completed, the fifth valve is opened to discharge the substances in the test chamber.

In some embodiments of the present application, the liquid storage tank contains an electrolyte to be tested.

In some embodiments of the present application, the liquid storage tank is a brown glass bottle, which can create a light-proof environment and prevent the electrolyte from denaturing.

In some embodiments of the present application, the inertizing agent is aluminum hydroxide, aluminum silicate, etc.

In another embodiment of the present application, a testing method for a lithium battery thermal runaway simulation test device is also provided. Using one of the above-mentioned lithium battery thermal runaway simulation test devices, the second valve is opened, and the test is performed according to the ejection valve that needs to be tested.

In some embodiments of the present application, when testing gaseous propellants, open the second valve and the third valve, calculate the flow rate of the gas sprayed into the test chamber by the second turbine flowmeter, use a spark plug to ignite the gas, and observe whether the ignition is successful. If not, spray out an amount of gas equal to the first injection again to observe whether the ignition is successful. Repeat the operation until the ignition is successful, and record the pressure and temperature information collected by the data acquisition instrument. Take the concentration of the first combustion as the lower flammable limit of the gas. On the basis of the lower flammable limit, inject an amount of gas equal to the first injection in batches to increase the gas concentration until no flame is observed. Record the pressure and temperature information collected by the data acquisition instrument. At this time, the concentration of the gas is the upper flammable limit of the gas.

Similarly, for the liquid-phase ejection test, the first valve and the second valve are opened, the flow rate of the ejected electrolyte is calculated by the first turbine flowmeter, the spark plug is ignited to ignite the electrolyte, and it is observed whether the ignition is successful. If not, the same amount of electrolyte is ejected again, and it is observed whether the ignition is successful. The operation is repeated until the ignition is successful, and the pressure information and temperature information collected by the data acquisition instrument are recorded; taking the concentration at the beginning of combustion as the starting point, the same amount of electrolyte is added in batches to increase the concentration of the electrolyte until no flame is observed, and the pressure and temperature information collected by the data acquisition instrument are recorded;

For the gas-liquid two-phase ejection test, open the first valve, the second valve and the third valve, spray the mixture of electrolyte and mixed gas from the nozzle, ignite the spark plug, and observe whether the ignition is successful. If not, spray the same amount of mixture at the nozzle again, and continue to observe whether the ignition is successful. Repeat the operation until ignition, and record the pressure information and temperature information collected by the data acquisition instrument; take the concentration at the beginning of combustion as the starting point, add the same amount of electrolyte and mixed gas in batches until no flame is observed, and record the pressure and temperature information;

When testing the propellant that requires the participation of an inert agent, the fourth valve is opened while the required valve is opened, and the inert agent is sprayed out at the nozzle.

In some embodiments of the present application, during the test, nine characteristic parameters of the mixture in the test chamber are obtained, namely, ignition point, maximum combustion temperature, maximum temperature change rate, maximum gas pressure, maximum pressure change rate, heat released during complete combustion, upper flammable limit, lower flammable limit, and gas toxicity; wherein the toxicity of the gas is the concentration of carbon monoxide in the mixture.

In some embodiments of the present application, among the nine characteristic parameters, the ignition point, the maximum combustion temperature, the maximum temperature change rate, the maximum air pressure, the maximum pressure change rate, and the heat released by complete combustion, the larger the value, the more dangerous it is; the smaller the lower flammable limit value, the more dangerous it is; the larger the upper flammable limit value, the more dangerous it is; gas toxicity is the carbon monoxide concentration in the mixed gas, the larger the value, the more dangerous it is.

In some embodiments of the present application, nine characteristic parameters are ranked for safety, and values are assigned according to the numbers 1, 2, 3, and 4, where the larger the value, the more dangerous it is; a 3×3 danger level matrix B is obtained; a product scaling method is applied to weight each parameter to obtain a 3×3 evaluation matrix A; the two matrices are multiplied to obtain a matrix C, and each value is accumulated to obtain a danger level value R;

The beneficial effects of the present application are at least as follows: the testing device of the present application can simulate various scenarios for thermal runaway of lithium batteries, and test various eruptions such as gas, liquid, and solid separately or in combination; since the inerting agent enhances the thermal stability of the electrolyte during thermal runaway, the present application analyzes its inerting effect; the gas-liquid two-phase eruption is ejected into the air and burns, and is toxic, and there is very little research on its safety assessment; at the same time, a testing method is provided that can effectively evaluate the safety of the eruption, providing an important reference for the safe use of lithium batteries and fire protection.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application is further described below in conjunction with the accompanying drawings and embodiments.

FIG1 is a schematic diagram of the structure of a lithium battery thermal runaway simulation test device in some embodiments of the present application;

FIG2 is a schematic diagram of the structure of a gas injection system in some embodiments of the present application;

FIG3 is a schematic diagram of the structure of a liquid injection system in some embodiments of the present application;

FIG4 is a schematic diagram of the structure of an inertizing agent injection system in some embodiments of the present application;

FIG5 is a schematic diagram of a test method flow chart of some embodiments of the present application:

FIG5 (a) is a schematic diagram of the test process of gas-phase ejecta;

FIG5( b ) is a schematic diagram of the test process of liquid phase ejecta;

FIG5( c ) is a schematic diagram of the test process of gas-liquid two-phase ejection;

Figure 5 (d) is a schematic diagram of the process of the inert agent participating in the test;

Among them, 100-liquid injection system, 200-test cabin, 300-gas injection system, 400-inerting agent injection system, 201-pressure sensor, 204-temperature sensor, 101-liquid storage tank, 102-first pump body, 103-first turbine flowmeter, first valve K1, 104-first flow valve, second valve K2, 202-bracket, 205-spark plug, 206-nozzle, 207-cabin, 208-fourth pump body, 301-second turbine flowmeter, 302-second pump body, 303-air bag, 304-gas storage tank, third valve K3, 305-second flow valve, 307-pressure detection display; 401-inerting agent storage tank, 402-third pump body, 403-third turbine flowmeter, fourth valve K4, 404-third flow valve; 500-data acquisition system, 501-data acquisition instrument, 502-computer, fifth valve K5.

Detailed ways

The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings and specific implementation methods. However, those skilled in the art will understand that the embodiments described below are part of the embodiments of the present application, rather than all of the embodiments, and are only used to illustrate the present application and should not be regarded as limiting the scope of the present application.

It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or relative positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present application. Unless otherwise specified, the above-mentioned directional description can be flexibly set in the process of actual application under the condition that the relative positional relationship shown in the drawings is met.

The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "connected" should be understood in a broad sense, such as fixed connection, detachable connection, and integral connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the electrical connection between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the present application, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, article or device including the element.

In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

The present application is further described in detail below through embodiments and in conjunction with Figures 1-5.

The present application provides a lithium battery thermal runaway simulation test device. In some embodiments of the present application, a lithium battery thermal runaway simulation test device is provided, which includes: a test chamber 200, a liquid injection system 100, a gas injection system 300, an inerting agent injection system 400, a pressure sensor 201, a temperature sensor 204, and a data acquisition system 500.

In some embodiments of the present application, the test chamber 200 includes a chamber body 207, in which a nozzle 206, a bracket 202, and a spark plug 205 are disposed; the nozzle 206 is located at the bottom of the test chamber 200, and the spark plug 205 is disposed on the bracket 202 located above the nozzle 206, and the bracket 202 is fixed in the test chamber 200.

In some embodiments of the present application, the liquid injection system 100 includes a liquid storage tank 101, a first pump body 102, a first turbine flowmeter 103, a first valve K1 and a first flow valve 104 which are sequentially connected through a liquid pipeline.

In some embodiments of the present application, the gas injection system 300 includes a gas storage tank 304, an air bag 303, a second pump body 302, a second turbine flowmeter 301, a third valve K3 and a second flow valve 305 which are sequentially connected through a gas pipeline.

In some embodiments of the present application, an inerting agent injection system 400 includes an inerting agent storage tank 401, a third pump body 402, a third turbine flowmeter 403, a fourth valve K4 and a third flow valve 404 which are sequentially connected through an inerting agent transmission pipeline;

In some embodiments of the present application, the pressure sensor 201 is used to obtain pressure information in the test chamber 200 .

In some embodiments of the present application, the pressure sensor 201 is placed through the right opening of the cabin 207 .

In some embodiments of the present application, the temperature sensor 204 is used to obtain temperature information in the test chamber 200 .

In some embodiments of the present application, the temperature sensor 204 is placed into the left opening of the cabin 207 .

In some embodiments of the present application, the data acquisition system 500 includes a data acquisition instrument 501 and a computer 502. The data acquisition instrument 501 is electrically connected to the pressure sensor 201 and the temperature sensor 204 to collect pressure and temperature information in the test chamber 200; the computer 502 is used to process the pressure and temperature data collected by the data acquisition instrument 501;

In some embodiments of the present application, the liquid pipeline, gas pipeline, and inerting agent transmission pipeline are all connected to one end of the mixture pipeline, and the other end of the mixture pipeline is connected to the nozzle 206 at the bottom of the test chamber 200. The mixed gas is transported to the nozzle 206 at the bottom of the test chamber 200 through the mixture pipeline, sprayed into the test chamber 200 by the nozzle 206, and ignited by the spark plug 205 for testing.

In some embodiments of the present application, a second valve K2K2 is provided on the mixture pipeline.

In some embodiments of the present application, the first valve K1, the second valve K2K2, the third valve K3 and the fourth valve K4 are used to control the on-off of the pipeline; the first turbine flowmeter 103, the second turbine flowmeter 301 and the third turbine flowmeter 403 are used to control the flow rate of the pipeline; the first flow valve 104, the second flow valve 305 and the third flow valve 404 adjust the valve opening according to the numerical value of the turbine flowmeter of the respective pipeline.

In some embodiments of the present application, the test chamber 200 is an insulated container.

In some embodiments of the present application, the nozzle 206 is in the shape of an inverted umbrella.

In some embodiments of the present application, there are multiple gas storage tanks 304, and the multiple gas storage tanks 304 respectively store battery-released gases such as hydrogen, methane, carbon monoxide, ethylene, and acetylene.

In some embodiments of the present application, the gas is modulated according to the ratio of gas released by the thermal runaway of the lithium iron phosphate battery and then flushed into the air bag 303 for standby use.

In some embodiments of the present application, the nozzle 206 is connected to the fourth pump body 208 via a fifth valve K5. When the test is completed, the fifth valve K5 is opened to discharge the material in the test chamber 200.

In some embodiments of the present application, the liquid storage tank 101 contains an electrolyte to be tested.

In some embodiments of the present application, the liquid storage tank 101 is a brown glass bottle, which can create a light-proof environment and prevent the electrolyte from being denatured.

In some embodiments of the present application, the inertizing agent is aluminum hydroxide, aluminum silicate, etc.

In some embodiments of the application, the testing device further includes a pressure detection device, which is used to detect the pressure in the gas tank 304 and display the data in the pressure detection display 307 .

In some embodiments of the present application, the testing device further includes a camera for monitoring changes in the testing chamber 200 .

Referring to (a) in FIG. 5 , (b) in FIG. 5 , (c) in FIG. 5 , and (d) in FIG. 5 , in another embodiment of the present application, a test method for a lithium battery thermal runaway simulation test device is further provided, using one of the above-mentioned lithium battery thermal runaway simulation test devices,

When testing gaseous propellants, open the second valve K2K2 and the third valve K3, calculate the flow rate of the gas sprayed to the test chamber 200 through the second turbine flowmeter 301, use the spark plug 205 to ignite the gas, and observe whether the ignition is successful. If not, spray out the same amount of gas as the first injection again to observe whether the ignition is successful. Repeat the operation until the ignition is successful, and record the pressure and temperature information collected by the data acquisition instrument 501; take the concentration of the first combustion as the lower flammable limit of the gas, and on the basis of the lower flammable limit, inject the same amount of gas as the first injection in batches to increase the gas concentration until no flame is observed, and record the pressure and temperature information collected by the data acquisition instrument 501. At this time, the concentration of the gas is the upper flammable limit of the gas.

Similarly, when testing liquid-phase ejecta, open the first valve K1 and the second valve K2K2, calculate the flow rate of the ejected electrolyte through the first turbine flowmeter 103, ignite the spark plug 205 to ignite the electrolyte, and observe whether the ignition is successful. If not, eject the same amount of electrolyte again, and continue to observe whether it is ignited. Repeat the operation until the ignition is successful, and record the pressure information and temperature information collected by the data acquisition instrument 501; take the concentration at the beginning of combustion as the starting point, add the same amount of electrolyte in batches, increase the concentration of the electrolyte, until no flame is observed, and record the pressure and temperature information collected by the data acquisition instrument 501;

When testing the gas-liquid two-phase ejection material, open the first valve K1, the second valve K2K2 and the third valve K3, spray the mixture of electrolyte and mixed gas from the nozzle 206, ignite the spark plug 205, and observe whether the ignition is successful. If not, spray the same amount of mixture from the nozzle 206 again, and continue to observe whether the ignition is successful. Repeat the operation until ignition, and record the pressure information and temperature information collected by the data acquisition instrument 501; take the concentration at the beginning of combustion as the starting point, add the same amount of electrolyte and mixed gas in batches until no flame is observed, and record the pressure and temperature information;

When testing a propellant that requires the participation of an inert agent, the fourth valve K4 is opened while the required valves are opened, and the inert agent is sprayed out at the nozzle 206 .

As shown in Figure 5, in some embodiments of the present application, the gas injection system 300 can achieve a single injection of 0.2/0.3/0.4 vol% of the mixed gas, and the gas is distributed according to the various gas components of the thermal runaway exhaust of the lithium iron phosphate battery in the test experiment, and the gas is stored in the air bag 303 after distribution. The second pump body 302 provides a pressure difference to extract the gas from the air bag 303; observe the second turbine flowmeter 301 to adjust the opening of the second flow valve 305, and control the closing time of the third valve K3 after the gas flow rate stabilizes to achieve quantitative injection; the interval time of opening and closing the third valve K3 is calculated by the formula c =Svt⁄L to achieve the control of the concentration of the single injected gas to 0.2/0.3/0.4 vol%, where S represents the cross-sectional area of the pipeline, v represents the flow rate, t represents the time, L represents the volume of the test chamber 200, and c represents the concentration.

In some embodiments of the present application, the pipe cross-sectional area S is 28.26 cm ² , the flow velocity v is 2.5 m/s, the volume L of the test chamber 200 is 50 L, and the valve port closing interval calculated by the formula is 1.4 seconds. Appropriately reducing the pipe cross-sectional area and reducing the flow velocity can extend the valve port closing interval, which is beneficial to the accuracy of quantitative determination.

In some embodiments of the present application, it is possible to conduct safety tests on two-phase or three-phase propellants. After the single-phase combustible material to be tested is injected into the system and debugged, and the closure of the corresponding valves is controlled at the same time, a combustible mixture can be generated in the test chamber 200 to perform tests and obtain data.

In some embodiments of the present application, taking the test of single-phase gas ejection as an example, after first checking the sealing of the test chamber 200 and the normal operation of the sensor, 0.2/0.3/0.4 vol% of combustible gas is first injected into the test chamber 200, and the spark plug 205 is ignited to try to ignite. If it fails to ignite, 0.2/0.3/0.4 vol% of combustible gas is injected again, and ignition is tried again until ignition is successful, and the temperature and pressure data transmitted by the pressure sensor 201 and the temperature sensor 204 acquired by the data acquisition instrument 501 are recorded; at this time, the concentration of the first fuel is the lower flammable limit of the gas;

After cleaning the test chamber 200, inject a 0.2/0.3/0.4vol% combustible mixture based on the lower flammable limit concentration of the gas and try to ignite it. If ignition is successful, inject n times of 0.2/0.3/0.4vol combustible mixture based on the lower flammable limit concentration of the gas until ignition fails. Record the data. The concentration at this time is the upper flammable limit of the gas.

The appearance of a light blue flame is considered successful.

The sensor can obtain the ignition point, maximum combustion temperature, maximum gas pressure, maximum pressure change rate, upper flammable limit, and lower flammable limit data.

In some embodiments of the present application, the maximum temperature change rate can be expressed as It can be concluded that the maximum pressure change rate can be obtained by formula/> The heat released can be used to It is concluded that q is the calorific value of each gas, /> is the density of each gas, c is the concentration of the mixed gas, L is the volume of the test chamber 200, /> is the ratio of gas to the mixed gas.

In some embodiments of the present application, when liquid-phase eruption material is required to participate, the first valve K1 and the second valve K2K2 are opened, the first turbine flowmeter 103 is observed to adjust the opening of the first flow valve 104, and the opening and closing of the first valve K1 are controlled to realize liquid injection. The calculation method of the closing interval time of the first valve K1 refers to the gas injection system 300, and the liquid is injected each time at 0.2/0.3/0.4 vol%, and the rest of the test process is the same as the gas injection process.

In some embodiments of the present application, when an inert agent is required, the third air pump extracts the inert agent from the inert agent storage tank 401, and controls the opening and closing of the fourth valve K4 to inject the inert agent into the test chamber 200. The calculation method of the closing interval time of the fourth valve K4 refers to the calculation of gas injection. The amount of inert agent injected each time is 0.1/0.2/0.3 g/L, and the rest of the test process is the same as the gas injection test process.

In some embodiments of the present application, for the convenience of calculation and processing, nine dangerous quantities are represented by letters: ignition point a, maximum temperature change rate b, maximum pressure c, maximum combustion temperature d, maximum pressure change rate e, heat f, upper flammable limit g, lower flammable limit h, gas toxicity i. The numbers 1, 2, 3, 4 are assigned according to the actual data range.

In some embodiments of the present application, nine characteristic parameters are ranked in safety order and assigned values according to the numbers 1, 2, 3, and 4. The larger the value, the more dangerous it is, and a 3×3 danger level matrix B is obtained. For details, please refer to Table 1:

Table 1 is a scoring reference table;

The product scaling method is applied to weight each parameter to obtain a 3×3 evaluation matrix A. The two matrices are multiplied to obtain C, and each value is accumulated to obtain the danger level value R.

In some embodiments of the present application, the most dangerous is the toxicity i of the gas, which is weighted as 3.360. The second most dangerous is the ignition point a, which is weighted as 2.482. The detailed evaluation parameter matrix is as follows.

The matrix C is obtained by multiplying the hazard level matrix B and the evaluation matrix A. The parameters of the matrix C are added to get the final result. The hazard level evaluation is carried out according to the hazard level evaluation table in Table 2. There are four levels: Ⅰ, Ⅱ, Ⅲ, and Ⅳ. Among them, Ⅰ is relatively the safest and Ⅳ is relatively the most dangerous. The settings of the four levels are shown in Table 2.

Table 2 Hazard level evaluation table

According to the test method of the present application, the numerical values of the nine characteristic parameters obtained by the test are assigned to obtain a matrix B, which is multiplied by the weighted matrix A to obtain a matrix C. The sum of the various parameters of the matrix C corresponds to the danger level, which can provide an important reference for fire protection.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims (10)

1. A lithium battery thermal runaway simulation test device, comprising: A test chamber, the test chamber comprising a chamber body, wherein a nozzle, a bracket, and a spark plug are arranged in the chamber body; the nozzle is located at the bottom of the test chamber, the spark plug is arranged on the bracket located above the nozzle, and the bracket is fixed in the test chamber; A liquid injection system, comprising a liquid storage tank, a first pump body, a first turbine flowmeter, a first valve and a first flow valve which are sequentially connected through a liquid pipeline; A gas injection system, comprising a gas storage tank, a gas bag, a second pump body, a second turbine flowmeter, a third valve and a second flow valve which are sequentially connected via a gas pipeline; An inerting agent injection system, comprising an inerting agent storage tank, a third pump body, a third turbine flowmeter, a fourth valve and a third flow valve which are sequentially connected via an inerting agent transmission pipeline; A pressure sensor, used to obtain pressure information in the test chamber; Temperature sensor, used to obtain temperature information in the test chamber; The data acquisition system includes a data acquisition instrument and a computer. The data acquisition instrument is electrically connected to the pressure sensor and the temperature sensor to collect pressure and temperature information in the test chamber. The computer is used to process the pressure and temperature data collected by the data acquisition instrument. The liquid pipeline, gas pipeline, and inerting agent transmission pipeline are all connected to one end of the mixture pipeline, and the other end of the mixture pipeline is connected to the nozzle at the bottom of the test chamber. The mixed gas is transported to the nozzle at the bottom of the test chamber through the mixture pipeline, sprayed into the test chamber by the nozzle, and ignited by the spark plug for testing. 2. A lithium battery thermal runaway simulation test device according to claim 1, characterized in that: A second valve is arranged on the mixture pipeline; the first valve, the second valve, the third valve and the fourth valve are used to control the on-off of the pipeline; and the opening of the flow valve of the pipeline is controlled according to the values of the first turbine flowmeter, the second turbine flowmeter and the third turbine flowmeter. 3. A lithium battery thermal runaway simulation test device according to claim 1, characterized in that: The test chamber is an insulated container; the nozzle is in the shape of an inverted umbrella; and there are multiple gas storage tanks. 4. A lithium battery thermal runaway simulation test device according to claim 1, characterized in that: The nozzle is connected to the fourth pump body through the fifth valve. When the material in the test chamber needs to be released, the fifth valve is opened to discharge the material in the test chamber. 5. A lithium battery thermal runaway simulation test device according to claim 1, characterized in that: The liquid storage tank is filled with the electrolyte to be tested. 6. A test method for a lithium battery thermal runaway simulation test device, characterized in that the test is performed using the lithium battery thermal runaway simulation test device according to any one of claims 1 to 5: When testing gaseous propellants, open the second valve and the third valve, calculate the flow rate of the gas sprayed to the test chamber by the second turbine flowmeter, use the spark plug to ignite the gas, and observe whether the ignition is successful. If not, spray out the same amount of gas as the first injection again, and observe whether the ignition is successful. Repeat the operation until the ignition is successful, and record the pressure and temperature information collected by the data acquisition instrument; The concentration of the first combustion is taken as the lower flammable limit of the gas. On the basis of the lower flammable limit, the same amount of gas as the first injection is injected in batches to increase the gas concentration until no flame is observed. The pressure and temperature information collected by the data acquisition instrument are recorded. At this time, the gas concentration is the upper flammable limit of the gas. Similarly, for the liquid phase ejection test, the first valve and the second valve are opened, the flow rate of the ejected electrolyte is calculated by the first turbine flowmeter, the spark plug is ignited to ignite the electrolyte, and whether the ignition is successful is observed. If not, the same amount of electrolyte is ejected again, and whether the ignition is continued to be observed, and the operation is repeated until the ignition is successful, and the pressure information and temperature information collected by the data acquisition instrument are recorded; Taking the concentration at the beginning of combustion as the starting point, add equal amounts of electrolyte in batches to increase the concentration of electrolyte until no flame is observed, and record the pressure and temperature information collected by the data acquisition instrument; for the gas-liquid two-phase ejection test, open the first valve, the second valve and the third valve, spray a mixture of electrolyte and mixed gas from the nozzle, ignite the spark plug, and observe whether the ignition is successful. If not, spray an equal amount of mixture at the nozzle again, and continue to observe whether the ignition is successful. Repeat the operation until ignition is achieved, and record the pressure and temperature information collected by the data acquisition instrument; Taking the concentration at the beginning of combustion as the starting point, add equal amounts of electrolyte and mixed gas in batches until no flame is observed, and record the pressure and temperature information; When testing an ejection material that requires the participation of an inert agent, the fourth valve is opened while the valve corresponding to the desired ejection material is opened, and the inert agent is sprayed out at the nozzle. The testing process is the same as that of the gas phase ejection material. 7. The testing method of a lithium battery thermal runaway simulation testing device according to claim 6, characterized in that: During the test, nine characteristic parameters of the mixture in the test chamber are obtained, namely, ignition point, maximum combustion temperature, maximum temperature change rate, maximum gas pressure, maximum pressure change rate, heat released during complete combustion, upper flammable limit, lower flammable limit, and gas toxicity; wherein the toxicity of the gas is the concentration of carbon monoxide in the mixture. 8. The testing method of a lithium battery thermal runaway simulation testing device according to claim 7, characterized in that: Among the nine characteristic parameters, the larger the ignition point, the maximum combustion temperature, the maximum temperature change rate, the maximum air pressure, the maximum pressure change rate, and the heat released by complete combustion, the more dangerous it is; the smaller the lower flammable limit value, the more dangerous it is; the larger the upper flammable limit value, the more dangerous it is; gas toxicity is the carbon monoxide concentration in the mixed gas; the larger the value, the more dangerous it is. 9. The testing method of a lithium battery thermal runaway simulation testing device according to claim 8, characterized in that: The nine characteristic parameters are ranked in safety order and assigned values according to 1, 2, 3, and 4. The larger the value, the more dangerous it is. A 3×3 danger level matrix B is obtained. The product scaling method is used to assign weights to each parameter to obtain a 3×3 evaluation matrix A. The two matrices are multiplied to obtain a matrix C. Each value is accumulated to obtain a danger level value R. . 10. The testing method of a lithium battery thermal runaway simulation testing device according to claim 9, characterized in that: The danger level is judged according to the danger degree value R. There are four levels: Ⅰ, Ⅱ, Ⅲ, and Ⅳ. Among them, Ⅰ is relatively the safest and Ⅳ is relatively the most dangerous.