Evaluation system and evaluation method for explosion suppression and fire suppression device of power lithium ion storage battery box of electric motor coach

Abstract

The invention provides an evaluation system and evaluation method for an explosion and fire suppression device of a power lithium ion storage battery box of an electric motor coach, and the evaluation method is characterized in that a battery model combination composed of a plurality of aluminum simulation blocks is arranged in a simulation battery box, and a heating rod is embedded in one of the simulation blocks to serve as a thermal runaway simulation block; through different simulation scene tests of an initial thermal runaway suppression test and an initial entity fire suppression test, the verification and evaluation of the fire prevention and control effectiveness of the lithium ion power battery by the explosion suppression and fire suppression device can be quickly realized, and the system has the advantages of high universality, strong operability, simple structure, low cost and convenience in maintenance.

Description

Technical Field

[0001] The invention belongs to the technical field of fire test and experiment, and more specifically relates to a test and evaluation method for an explosion and fire suppression device of a power lithium-ion battery box of an electric bus. Background Art

[0002] As a new energy-driven transportation tool, electric vehicles are highly favored for their advantages such as low pollution, low noise and high energy efficiency, and have become a major trend in the development of modern automobiles. Lithium-ion power batteries are key systems of electric vehicles, but they have a high risk of fire. Battery fires occur frequently during the use of electric vehicles, causing a great social impact. Especially for electric buses, due to the large number of passengers they carry, once a fire occurs, it will cause significant casualties.

[0003] In order to verify, evaluate and assess the effectiveness of explosion and fire suppression devices in preventing and controlling lithium-ion power battery fires, it is an urgent problem that technical personnel in this field need to solve by simulating to a certain extent the actual working conditions of electric bus power lithium-ion battery boxes when a fire occurs, and assisting in the formulation or revision of relevant standards and specifications. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides the following technical solutions:

[0005] An explosion and fire suppression device evaluation system for a power lithium-ion battery box of an electric bus includes a simulated battery box, the box body of the simulated battery box is equipped with two types of box cover plates for sealing the box opening:

[0006] A first box cover plate, which is used in the initial thermal runaway suppression test to completely seal the inner cavity of the box;

[0007] The second box cover is used in the initial physical fire suppression test to seal the box opening of the box body and is provided with a pressure relief port;

[0008] The side walls of the box are respectively installed with:

[0009] A combustible gas release nozzle is connected to a gas mixing device via a pipeline. After the gas mixing device is started, the mixed gas output can be released into the box of the simulated battery box by the combustible gas release nozzle;

[0010] An ignition needle is used to ignite the mixed gas sprayed into the inner cavity of the box by the combustible gas release nozzle;

[0011] A fire extinguishing agent nozzle, which is connected to the explosion and fire suppression device to be evaluated through a pipeline;

[0012] The inner cavity of the box accommodates and arranges a battery model combination, which includes a plurality of simulation blocks. One simulation block is used to simulate a group of cells of a lithium battery module, and the size of the simulation block should be similar to the size of the cell it simulates. The total number of simulation blocks and the arrangement of the simulation blocks are generally determined according to the actual design requirements of the target lithium battery module. One simulation block is used to test and simulate the triggering of thermal runaway, and the simulation block is defined as a thermal runaway simulation block. The thermal runaway simulation block is provided with a plurality of blind holes, and a heating rod for electric heating is embedded in each blind hole.

[0013] Thermocouples for temperature measurement are also attached to the sides of the thermal runaway simulation block and the surrounding simulation blocks.

[0014] Further, it also includes: igniter, explosion-proof glass, ignition control cabinet, temperature monitoring equipment and monitoring display;

[0015] The explosion-proof glass separates the experimental site into two areas: the test area and the monitoring area; the simulated battery box and igniter are placed in the test area, and the gas mixing device, ignition control cabinet, temperature monitoring equipment and monitoring display are placed in the monitoring area.

[0016] Furthermore, the gas mixing device includes a CO gas cylinder, an H2 gas cylinder and a CH4 gas cylinder, which respectively store three kinds of combustible gases, CO, H2 and CH4. The output pipeline of each gas cylinder is respectively provided with a pressure reducing valve, a manual ball valve, a needle valve, a gas flow meter and a one-way valve in sequence. The output pipelines of the three gas cylinders are merged through a four-way manifold and then flow into a mixing chamber through a one-way valve. The proportion of the three combustible gases entering the mixing chamber is adjusted by adjusting control valves such as the manual ball valve on the output pipelines of the three combustible gases, and the gases are mixed in the mixing chamber at a ratio of 1:2:6. A manual ball valve and a needle valve are provided on the gas outlet pipeline of the mixing chamber to control the flow rate of the mixed gas output, and the end of the gas outlet pipeline is connected to the combustible gas release nozzle.

[0017] Furthermore, the first box cover is provided with an observation port sealed by high-temperature resistant and high-strength glass; the opening size of the pressure relief port of the second box cover is 1% to 5% of the box opening area; the opening position of the pressure relief port on the second box cover should ensure that the fire suppressant can be evenly sprayed into the inner cavity of the box, and can avoid the fire suppressant from leaking too quickly and affecting the fire extinguishing effect.

[0018] Furthermore, three types of gas detectors are installed on the side wall of the box, namely a CO detector, a H2 detector, and a CH4 detector; the three gas detectors are installed on the same side wall of the box and are arranged in sequence.

[0019] Furthermore, the fire extinguishing agent nozzle and the combustible gas release nozzle are respectively installed on the two side walls of the box body that are directly opposite to each other, and the fire extinguishing agent nozzle and the combustible gas release nozzle are respectively located at the center of their respective box walls.

[0020] Furthermore, the position setting rule of the thermal runaway simulation block in the battery model combination laid in the inner cavity of the box is: the thermal runaway simulation block is located in the simulation block row arranged between the combustible gas release nozzle and the fire extinguishing agent nozzle, and the interval between the thermal runaway simulation block and the combustible gas release nozzle is at least one and at most three simulation blocks;

[0021] The number of heating rods embedded in the thermal runaway simulation block is not less than four, and the heating power of the heating rods is proportional to the energy E of the triggering object.

[0022] The present invention also provides an evaluation method for an explosion and fire suppression device evaluation system of a power lithium-ion battery box of an electric bus as described above, comprising:

[0023] 1. Initial thermal runaway suppression test

[0024] Arrange the battery model assembly inside a box simulating a battery box;

[0025] Adopting a first box cover plate to close the box body;

[0026] The heating rod is powered on to heat the thermal runaway simulation block until the thermal runaway temperature is reached, and then the heating is stopped;

[0027] Turn on the gas mixing device to continuously release the mixed combustible gas into the simulated battery box, and manually start the explosion and fire suppression device;

[0028] Since the explosion and fire suppression device is started, the ignition needle in the control box is ignited once every 3 minutes to observe whether there is deflagration in the box; and record the temperature data measured by the thermocouples at each temperature measuring point in the box within the specified time;

[0029] 2. Initial solid fire suppression test

[0030] Arrange the battery model assembly in the inner cavity of the box, and seal the box with a second box cover plate;

[0031] The heating rod is powered on to heat the thermal runaway simulation block until the thermal runaway temperature is reached, and the power of the heating rod is turned off to stop heating;

[0032] Turn on the gas mixing device to continuously release the mixed combustible gas into the simulated battery box, ignite the mixed combustible gas in the box and continue to burn for 3 minutes, then manually start the explosion and fire suppression device;

[0033] After the open fire in the box is extinguished by the explosion and fire suppression device, ignite once at the pressure relief port of the second box cover every 3 minutes to observe whether there is re-ignition in the box; record the time taken by the explosion and fire suppression device to extinguish the fire, as well as the temperature data measured by each thermocouple in the box within 30 minutes after the open fire is extinguished;

[0034] 3. Evaluation: The explosion and fire suppression device is qualified if it meets the following conditions:

[0035] In the initial thermal runaway inhibition test:

[0036] a) No deflagration or open flame should occur within 30 minutes after the suppression medium begins to be sprayed;

[0037] b) Within 30 minutes after the suppression medium begins to be sprayed, except for the thermocouple attached to the thermal runaway simulation block, the temperature measured by the thermocouples on other simulation blocks shall not exceed 90°C;

[0038] In the initial physical fire suppression test:

[0039] a) Extinguish the open fire within 90 seconds after the suppression medium begins to release;

[0040] b) No re-ignition, deflagration or explosion should occur within 30 minutes after the open fire is extinguished;

[0041] c) Within 30 minutes after the open fire was extinguished, the ignition continued at the pressure relief port of the second tank cover without deflagration or explosion;

[0042] d) Within 30 minutes after the open fire is extinguished, except for the thermocouple attached to the thermal runaway simulation block, the temperature measured by the thermocouples on other simulation blocks shall not exceed 90°C.

[0043] Furthermore, in the initial thermal runaway suppression test, the flow rate and duration of the continuous release of the mixed combustible gas into the box of the simulated battery box are performed in one of the following situations:

[0044] Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 91*27*148mm, and the power range of the heating rod is 300~1000W, then the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release time is set to 2min;

[0045] Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release time is 4 min;

[0046] Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min.

[0047] Furthermore, in the initial physical fire suppression test, the flow rate of the mixed combustible gas continuously released into the box of the simulated battery box is performed according to one of the following conditions:

[0048] Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the simulated battery box size is 1060*630*250mm, the simulated lithium battery cell size is 91*27*148mm, and the heating rod power range is 300~1000W, then the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release is 2min;

[0049] Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release is 4 minutes;

[0050] Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min.

[0051] The evaluation system of the present invention can quickly verify and evaluate the effectiveness of explosion and fire suppression devices in preventing and controlling fires of lithium-ion power batteries, has high versatility, strong operability, simple structure, low cost and easy maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings that constitute a part of the present invention are used to provide further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 This is a structural diagram of the explosion and fire suppression device evaluation system;

[0054] Figure 2 is a schematic diagram of the structure of a gas mixing device;

[0055] Figure 3 It is the gas circuit principle diagram of the gas mixing device;

[0056] Figure 4 A schematic diagram of the top view of the simulated battery box.

[0057] Reference numerals in the figure: gas mixing device 1; simulated battery box 2; igniter 3; ignition needle 31; explosion-proof glass 4; ignition control cabinet 5; temperature monitoring device 6; monitoring display 7; fire extinguishing agent nozzle 8

[0058] Box body 21; combustible gas release nozzle 22; one-way flame arrester 221;

[0059] CO detector 231, H2 detector 232, CH4 detector 233; TC05 detector 24;

[0060] Simulation block 9; thermal runaway simulation block 91; heating rod 911; thermocouple 92. DETAILED DESCRIPTION

[0061] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0062] In the description of the embodiments of the present invention, it should be noted that the indicated orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the application product is usually placed when in use, or is the orientation or position relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention or simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0063] The term "plurality" in the present invention refers to more than two (including two). The terms "first", "second", etc. are only used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0064] Unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0065] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0066] like Figure 1As shown, the explosion and fire suppression device evaluation system of the present invention includes a gas mixing device 1, a simulated battery box 2, an igniter 3, explosion-proof glass 4, an ignition control cabinet 5, a temperature monitoring device 6 and a monitoring display 7.

[0067] The explosion-proof glass 4 separates the experimental site into two areas: the test area and the monitoring area; wherein the simulated battery box 2 and the igniter 3 are placed in the test area, and the ignition control cabinet 5, the temperature monitoring device 6 and the monitoring display 7 are placed in the monitoring area; personnel operate and view the progress of the experiment in the monitoring area, and can directly observe the situation in the test area through the explosion-proof glass 4. Preferably, the gas mixing device 1 is placed in the monitoring area, that is, the gas mixing device 1 is separated from the simulated battery box 2 and the igniter 3 by the explosion-proof glass 4, thereby enhancing safety protection.

[0068] like Figure 2 and Figure 3 As shown, the gas mixing device 1 includes a CO gas cylinder, an H2 gas cylinder and a CH4 gas cylinder, which respectively store three kinds of combustible gases, CO, H2 and CH4. A pressure reducing valve, a manual ball valve, a needle valve, a gas flow meter and a one-way valve are arranged on the output pipeline of each gas cylinder in sequence. The output pipelines of the three gas cylinders are merged through a four-way manifold and then flow into a mixing chamber through a one-way valve. The proportion of the three combustible gases entering the mixing chamber is adjusted by adjusting the manual ball valve and other control valves on the output pipelines of the three combustible gases. The gases are mixed in the mixing chamber at a ratio of 1:2:6. A manual ball valve and a needle valve are arranged on the gas outlet pipeline of the mixing chamber. To control the flow rate of the mixed gas output, the end of the gas outlet pipeline is connected to the combustible gas release nozzle 22 installed on the side wall of the box body 21 of the simulated battery box 2. The mixed gas is transported to the simulated battery box 2 through the gas outlet pipeline at a certain flow rate, and is released into the box body 21 of the simulated battery box 2 by the combustible gas release nozzle 22, so as to simulate the mixed combustible gas generated in the box body 21 when the battery is thermally runaway by the mixed gas. Furthermore, a one-way flame arrester 221 is also provided on the gas outlet pipeline, so that the mixed gas flows through the one-way flame arrester 221 before being transported to the combustible gas release nozzle 22 to prevent backfire.

[0069] like Figure 4 As shown, the simulated battery box 2 includes

[0070] Box body 21, the box body size should comply with the provisions of GB / T 34013-2017, and be similar to the battery box used in the explosion and fire suppression device; preferably, an observation port is provided on the box body 21 (such as the side wall), and the observation port is sealed with high-temperature resistant and high-strength glass to observe the real-time status of the inner cavity of the box body 21.

[0071] The box body 21 is equipped with two types of box cover plates (not shown in the figure) which can be replaced as needed to cover the box opening of the box body 21:

[0072] A first box cover, which is used in the initial thermal runaway suppression test to completely seal the inner cavity of the box body 21. Preferably, the first box cover is provided with an observation port sealed by high-temperature resistant and high-strength glass so that the real-time status of the inner cavity can be observed through the observation port;

[0073] The second box cover is used in the initial physical fire suppression test. It is used to seal the box opening of the box body 21 and is provided with a pressure relief port. The pressure relief port is used to simulate the pressure relief design of the actual vehicle battery box. The opening size of the pressure relief port should be determined according to the volume of the battery box and the injection pressure of the explosion and fire suppression device, usually 1% to 5% of the box opening area of ​​the box body 21. The opening position of the pressure relief port on the second box cover should ensure that the fire suppressant can be evenly sprayed into the inner cavity of the box body, and the fire suppressant should be prevented from leaking too quickly to affect the fire extinguishing effect.

[0074] The simulated battery box 2 also includes:

[0075] The three gas detectors are a CO detector 231, a H2 detector 232, and a CH4 detector 233; preferably, the three gas detectors are installed on the same side wall of the box body 21 and are arranged in sequence.

[0076] The ignition needle 31 is located on the inner wall of the box body near the combustible gas release nozzle 22, and is used to ignite the mixed gas sprayed into the inner cavity of the box body 21 by the combustible gas release nozzle 22; the ignition needle 31 is electrically connected to the igniter 3 through a cable passing through the box body 21 and especially controls the start and stop, and the igniter 3 is electrically connected to the ignition control cabinet 5 through a cable and is controlled by it;

[0077] The fire extinguishing agent nozzle 8 is connected to the explosion and fire suppression device to be evaluated (not shown) through a pipeline, and the fire suppressant transported from the explosion and fire suppression device through the pipeline is sprayed into the inner cavity of the box by the fire extinguishing agent nozzle 8; preferably, the fire extinguishing agent nozzle 8 and the combustible gas release nozzle 22 are respectively installed on the side walls opposite to each other of the box 21, and the fire extinguishing agent nozzle 8 and the combustible gas release nozzle 22 are respectively located at the center of their respective box walls.

[0078] The TC05 detector 24 is a carbon monoxide and temperature-sensitive composite fire detector for energy storage power stations; further, the TC05 detector 24 is located on the side wall of the box 21 where the fire extinguishing agent nozzle 8 is located.

[0079] Preferably, a pressure relief valve (not shown) is also installed on the box body 21, and the installation position of the pressure relief valve is the same as the installation position of the simulated battery box.

[0080] The inner cavity of the box body 21 of the simulated battery box 2 is used to accommodate and arrange the battery model combination, and the battery model combination includes a plurality of simulation blocks 9, one simulation block is used to simulate a group of cells of a lithium battery module, and the size of the simulation block should be similar to the size of the cell it simulates; the total number of simulation blocks and the arrangement of the laying are generally determined according to the actual design requirements of the target lithium battery module. Figure 4 In the embodiment shown in , a total of 36 simulation blocks are laid out in 3 rows and 12 columns in the inner cavity of the box 21, that is, 36 simulation blocks are selected and arranged in the form of 3 rows and 12 columns to form a "battery model combination" to simulate a lithium battery module.

[0081] Preferably, the lithium iron phosphate battery monomers in electric buses are mostly square batteries, and the dimensions of the square batteries should comply with GB / T 34013-2017 "Specifications and Dimensions of Power Storage Batteries for Electric Vehicles"; Figure 4 In the illustrated embodiment, each simulation block is in the shape of a rectangular parallelepiped.

[0082] One of the simulation blocks is used to test the triggering of thermal runaway, and the simulation block is defined as a thermal runaway simulation block 91. The simulation block is characterized in that a plurality of blind holes are opened on the simulation block, each of which has a heating rod 911 embedded in it. Each heating rod 911 is electrically connected to an electric heating control unit for controlling the electric heating of the heating rod 911 via a cable passing through the box body 21. The electric heating control unit can be integrated in the ignition control cabinet 5 for unified control, or it can be placed separately in an appropriate position in the monitoring area.

[0083] Furthermore, the position setting rule of the thermal runaway simulation block 91 in the battery model combination laid in the inner cavity of the box 21 is: located in the simulation block row arranged between the combustible gas release nozzle 22 and the fire extinguishing agent nozzle 8, and separated from the combustible gas release nozzle 22 by at least one and at most three simulation blocks, as close to the combustible gas release nozzle 22 as possible and away from the fire extinguishing agent nozzle 8, so as to simulate the typical thermal runaway origin point (such as the central area or near the pole ear), that is, the situation that is most likely to cause thermal runaway propagation and is least conducive to fire extinguishing. Figure 4 In the embodiment shown, the thermal runaway simulation block 91 is located in the second row of simulation blocks arranged between the combustible gas release nozzle 22 and the fire extinguishing agent nozzle 8, and an ordinary simulation block 9 is spaced between the thermal runaway simulation block 91 and the combustible gas release nozzle 22.

[0084] Further, the number of the heating rods 911 embedded in the thermal runaway simulation block 91 is not less than four, preferably, as Figure 4 As shown, the number of heating rods 911 embedded in the thermal runaway simulation block 91 is six, and they are evenly spaced in the thermal runaway simulation block 91. The total heating power of all heating rods 911 should meet the power requirement of simulating thermal runaway caused by internal short circuit of the battery box, and the total heating power of the heating rods 911 is proportional to the energy E of the triggering object.

[0085] Furthermore, the surface of the heating rod 911 is covered with ceramics or metal so as to quickly heat the triggering object with maximum power.

[0086] Furthermore, thermocouples 92 are attached to the sides of the thermal runaway simulation block 91 and the surrounding simulation blocks 9, respectively, for monitoring the real-time temperature of the thermal runaway simulation block 91 and the surrounding simulation blocks 9. Each thermocouple 92 is electrically connected to the temperature monitoring device 6 via a cable.

[0087] Corresponding information of the temperature detection device 6 , the ignition control cabinet 5 and / or the electric heating control unit can be displayed in real time through the monitoring display 7 .

[0088] The evaluation method of the explosion and fire suppression device evaluation system of the present invention comprises:

[0089] 1. Initial thermal runaway suppression test

[0090] (1) The scenario and purpose of the test simulation: When a battery cell experiences thermal runaway, electrolyte vaporization will occur, causing the internal pressure of the battery to increase, thereby opening the safety valve and causing electrolyte spraying. However, since the battery box is closed and the space is small, it does not have the conditions for combustion. In the early stage of thermal runaway, the cooling effect of the explosion and fire suppression device must be evaluated to prevent the thermal runaway from spreading to adjacent batteries. Therefore, the initial thermal runaway suppression test must be carried out under non-ignition conditions. At this time, the explosion and fire suppression device is activated and mainly plays the role of inerting explosion suppression.

[0091] (2) Experimental steps:

[0092] According to Figure 4 Arrange the relevant equipment in the manner shown, and arrange the battery model assembly inside the battery box;

[0093] The box body 21 is closed by using a first box cover plate;

[0094] The heating rod 911 is powered on to heat the thermal runaway simulation block 91 until the thermal runaway temperature is reached. The thermocouple measures that the surface temperature of the thermal runaway simulation block 91 reaches 300° C. The power of the heating rod 911 is turned off to stop heating.

[0095] The gas mixing device 1 is turned on, and the mixed combustible gas is continuously released into the box body 21 of the simulated battery box 2 through the combustible gas release nozzle 22, and the explosion and fire suppression device is manually started; wherein, the flow rate and duration of the continuous release of the mixed combustible gas into the box body 21 of the simulated battery box 2 are selected according to one of the following situations:

[0096] Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 91*27*148mm, and the power range of the heating rod is 300-1000W, the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release time is set to 2min. After the time is up, the gas mixing device 1 is turned off (i.e., the release of the mixed combustible gas is stopped, the same below, no further details are given);

[0097] Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release time is 4 min;

[0098] Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min;

[0099] Since the explosion and fire suppression device is started, the ignition needle 31 in the box is controlled to ignite once every 3 minutes to observe whether there is deflagration in the box; and the temperature data measured by the thermocouples at each temperature measuring point in the box within the specified time are recorded.

[0100] 2. Initial solid fire suppression test

[0101] (1) The scenario and purpose of the test simulation: When a large amount of flammable gas generated after thermal runaway of a battery cell encounters an open flame or electric spark in the battery box, combustion and explosion will occur, causing the temperature of the battery box to rise, thereby causing a large-scale thermal runaway. This test follows the most unfavorable principle and must artificially ignite the flammable gas to carry out an initial physical fire suppression test to assess the fire extinguishing and cooling effects of the explosion and fire suppression device. Considering that the battery box may collide and rupture, while ensuring that the mixed flammable gas can continue to burn, the test is carried out under the condition that there is a certain opening on the battery box cover (that is, a second box cover is used); in this test, the explosion and fire suppression device mainly plays the role of extinguishing fire and preventing re-ignition after activation.

[0102] (2) Experimental steps:

[0103] according to Figure 4 Arrange in the manner shown, the battery model assembly is arranged in the inner cavity of the box body 21, and the box body 21 is covered with a second box cover plate;

[0104] The heating rod 911 is powered on to heat the thermal runaway simulation block 91 until the thermal runaway temperature is reached. The thermocouple measures that the surface temperature of the thermal runaway simulation block 91 reaches 300° C. The power of the heating rod 911 is turned off to stop heating.

[0105] The gas mixing device 1 is turned on, and the mixed combustible gas is continuously released into the box body 21 of the simulated battery box 2 through the combustible gas release nozzle 22, and the mixed combustible gas in the box body 21 is ignited through the ignition needle 31 in the box body and continuously burns for 3 minutes, and then the explosion and fire suppression device is manually started; wherein, the flow rate of the mixed combustible gas continuously released into the box body 21 of the simulated battery box 2 is selected according to one of the following situations:

[0106] Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the simulated battery box size is 1060*630*250mm, the simulated lithium battery cell size is 91*27*148mm, and the heating rod power range is 300~1000W, then the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release is 2min;

[0107] Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release is 4 minutes;

[0108] Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min;

[0109] After the open flame in the box is extinguished by the explosion and fire suppression device, ignite once at the pressure relief port of the second box cover every 3 minutes to observe whether there is any re-ignition in the box; record the time taken by the explosion and fire suppression device to extinguish the fire, as well as the temperature data measured by each thermocouple in the box within 30 minutes after the open flame is extinguished.

[0110] III. Evaluation: Explosion and fire suppression devices are qualified if they meet the following conditions:

[0111] In the initial thermal runaway inhibition test:

[0112] a) No deflagration or open flame should occur within 30 minutes after the suppression medium begins to be sprayed;

[0113] b) Within 30 minutes after the suppression medium begins to be sprayed, except for the thermocouple attached to the thermal runaway simulation block 91, the temperature measured by the thermocouples on other simulation blocks is not greater than 90°C;

[0114] In the initial physical fire suppression test:

[0115] a) Extinguish the open fire within 90 seconds after the suppression medium begins to release;

[0116] b) No re-ignition, deflagration or explosion should occur within 30 minutes after the open fire is extinguished;

[0117] c) Within 30 minutes after the open fire was extinguished, the ignition continued at the pressure relief port of the second tank cover without deflagration or explosion;

[0118] d) Within 30 minutes after the open fire is extinguished, except for the thermocouple attached to the thermal runaway simulation block 91, the temperature measured by the thermocouples on other simulation blocks shall not exceed 90°C.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box, characterized in that: The simulated battery box (2) includes a box body (21) provided with two types of box cover plates for sealing the box opening: A first box cover plate, which is used in the initial thermal runaway suppression test to completely seal the inner cavity of the box; The second box cover is used in the initial physical fire suppression test to seal the box opening of the box body and is provided with a pressure relief port; The side walls of the box are respectively installed with: A combustible gas release nozzle (22) is connected to a gas mixing device via a pipeline, and after the gas mixing device is activated, the mixed gas output can be released into the box of the simulated battery box through the combustible gas release nozzle; An ignition needle (31) is used to ignite the mixed gas sprayed into the inner cavity of the box body by the combustible gas release nozzle; A fire extinguishing agent nozzle (8), which is connected to the explosion and fire suppression device to be evaluated via a pipeline; The inner cavity of the box accommodates and arranges a battery model combination, wherein the battery model combination includes a plurality of simulation blocks, wherein one simulation block is used to simulate a group of battery cells of a lithium battery module, and the size of the simulation block should be similar to the size of the battery cell it simulates; the total number of simulation blocks and the arrangement of the simulation blocks are generally determined according to the actual design requirements of the target lithium battery module, wherein one simulation block is used to test and simulate the triggering of thermal runaway, and the simulation block is defined as a thermal runaway simulation block (91), and a plurality of blind holes are opened on the thermal runaway simulation block, and a heating rod (911) for electric heating is embedded in each blind hole; Thermocouples (92) for measuring temperature are also attached to the thermal runaway simulation block (91) and the surrounding simulation blocks (9) thereof.

2. The explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box according to claim 1, characterized in that: Also includes: Ignitor (3), explosion-proof glass (4), ignition control cabinet (5), temperature monitoring equipment (6) and monitoring display (7); The explosion-proof glass separates the experimental site into two areas: the test area and the monitoring area; the simulated battery box and igniter are placed in the test area, and the gas mixing device, ignition control cabinet, temperature monitoring equipment and monitoring display are placed in the monitoring area.

3. The explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box according to claim 1, characterized in that: The gas mixing device comprises a CO gas cylinder, an H2 gas cylinder and a CH4 gas cylinder, which respectively store three kinds of combustible gases, CO, H2 and CH4. A pressure reducing valve, a manual ball valve, a needle valve, a gas flow meter and a one-way valve are arranged on the output pipeline of each gas cylinder in sequence. The output pipelines of the three gas cylinders flow into a mixing chamber through a one-way valve after being merged by a four-way manifold. The proportion of the three combustible gases entering the mixing chamber is adjusted by adjusting control valves such as the manual ball valve on the output pipelines of the three combustible gases. The gases are mixed in the mixing chamber at a ratio of 1:2:

6. A manual ball valve and a needle valve are arranged on the gas outlet pipeline of the mixing chamber to control the flow rate of the mixed gas output. The end of the gas outlet pipeline is connected to a combustible gas release nozzle.

4. The explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box according to claim 1, characterized in that: The first box cover is provided with an observation port sealed by high-temperature resistant and high-strength glass; the opening size of the pressure relief port of the second box cover is 1% to 5% of the box opening area; the opening position of the pressure relief port on the second box cover should ensure that the fire suppressant can be evenly sprayed into the inner cavity of the box, and can avoid the fire suppressant from leaking too quickly and affecting the fire extinguishing effect.

5. The explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box according to claim 1, characterized in that: Three types of gas detectors are also installed on the side wall of the box, namely CO detector, H2 detector and CH4 detector; the three gas detectors are installed on the same side wall of the box and are arranged in sequence.

6. The explosion and fire suppression device evaluation system for electric bus power lithium-ion battery box according to claim 1, characterized in that: The fire extinguishing agent nozzle and the combustible gas release nozzle are respectively installed on the two side walls of the box body that are directly opposite to each other, and the fire extinguishing agent nozzle and the combustible gas release nozzle are respectively located at the center of the box wall where they are located.

7. An electric bus power lithium-ion battery box explosion and fire suppression device evaluation system as claimed in claim 1 or 6, characterized in that: The position setting rule of the thermal runaway simulation block in the battery model combination laid in the inner cavity of the box is: the thermal runaway simulation block is located in the simulation block row arranged between the combustible gas release nozzle and the fire extinguishing agent nozzle, and the interval between the thermal runaway simulation block and the combustible gas release nozzle is at least one and at most three simulation blocks; The number of heating rods embedded in the thermal runaway simulation block is not less than four, and the heating power of the heating rods is proportional to the energy E of the triggering object.

8. The evaluation method of the explosion and fire suppression device evaluation system for the electric bus power lithium-ion battery box as claimed in claim 1, characterized in that: include:

1. Initial thermal runaway suppression test Arrange the battery model assembly inside a box simulating a battery box; The box body is closed by using a first box cover plate; The heating rod is powered on to heat the thermal runaway simulation block until the thermal runaway temperature is reached, and then the heating is stopped; Turn on the gas mixing device to continuously release the mixed combustible gas into the simulated battery box, and manually start the explosion and fire suppression device; Since the explosion and fire suppression device is started, the ignition needle in the control box is ignited once every 3 minutes to observe whether there is deflagration in the box; and record the temperature data measured by the thermocouples at each temperature measuring point in the box within the specified time; 2. Initial solid fire suppression test Arrange the battery model assembly in the inner cavity of the box, and seal the box with a second box cover plate; The heating rod is powered on to heat the thermal runaway simulation block until the thermal runaway temperature is reached, and the power of the heating rod is turned off to stop heating; Turn on the gas mixing device to continuously release the mixed combustible gas into the simulated battery box, ignite the mixed combustible gas in the box and continue to burn for 3 minutes, then manually start the explosion and fire suppression device; After the open fire in the box is extinguished by the explosion and fire suppression device, ignite once at the pressure relief port of the second box cover every 3 minutes to observe whether there is re-ignition in the box; record the time taken by the explosion and fire suppression device to extinguish the fire, as well as the temperature data measured by each thermocouple in the box within 30 minutes after the open fire is extinguished; 3. Evaluation: The explosion and fire suppression device is qualified if it meets the following conditions: In the initial thermal runaway inhibition test: a) No deflagration or open flame should occur within 30 minutes after the suppression medium begins to be sprayed; b) Within 30 minutes after the suppression medium begins to be sprayed, except for the thermocouple attached to the thermal runaway simulation block, the temperature measured by the thermocouples on other simulation blocks shall not exceed 90°C; In the initial physical fire suppression test: a) Extinguish the open fire within 90 seconds after the suppression medium begins to release; b) No re-ignition, deflagration or explosion should occur within 30 minutes after the open fire is extinguished; c) Within 30 minutes after the open fire was extinguished, the ignition continued at the pressure relief port of the second tank cover without deflagration or explosion; d) Within 30 minutes after the open fire is extinguished, except for the thermocouple attached to the thermal runaway simulation block, the temperature measured by the thermocouples on other simulation blocks shall not exceed 90°C.

9. The evaluation method of the explosion and fire suppression device evaluation system according to claim 8, characterized in that: In the initial thermal runaway suppression test, the flow rate and duration of the continuous release of the mixed combustible gas into the simulated battery box are performed in one of the following conditions: Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 91*27*148mm, and the power range of the heating rod is 300~1000W, then the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release time is set to 2min; Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release time is 4 min; Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min.

10. The evaluation method of the explosion and fire suppression device evaluation system according to claim 8, characterized in that: In the initial physical fire suppression test, the flow rate of the mixed combustible gas continuously released into the simulated battery box is performed according to one of the following conditions: Case 1: If the capacity of the simulated lithium battery cell is less than 100Ah, the simulated battery box size is 1060*630*250mm, the simulated lithium battery cell size is 91*27*148mm, and the heating rod power range is 300~1000W, then the continuous release flow rate of the mixed combustible gas is set to 18L / min, and the continuous release is 2min; Case 2: If the capacity of the simulated lithium battery cell is between 100 and 200 Ah, the size of the simulated battery box is 1060*630*250 mm, the size of the simulated lithium battery cell is 171*48*173 mm, and the power range of the heating rod is 300 to 2000 W, the continuous release flow rate of the mixed combustible gas is set to 18 L / min, and the continuous release is 4 minutes; Case 3: If the capacity of the simulated lithium battery cell is greater than 200Ah, the size of the simulated battery box is 1060*630*250mm, the size of the simulated lithium battery cell is 205*72*173mm, and the power of the heating rod is greater than 600W, the continuous release flow rate of the mixed combustible gas is set to 22.5L / min, and the continuous release time is 8min.

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