Power battery fire prevention and control system test platform

Abstract

The invention discloses a test platform for a fire prevention and control system of a power battery, which is used for testing the performance of the fire prevention and control system of the power battery for rail transit by considering two stages of prevention and control, and can provide an automatic fire extinguishing performance test process to the greatest extent through a test platform host, avoid human judgment / intervention by 100%, and improve the test efficiency. An effective means is provided for test verification of a lithium ion power battery fire prevention and control system for rail transit, and the problems of battery fire and even locomotive fire caused by thermal runaway of the battery under the conditions of overcharge, short circuit, over-temperature and the like of the power battery are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of test platform design, and in particular relates to a power battery fire prevention and control system test platform. Background Art

[0002] With the development of technology, in order to respond to the country's requirements for energy conservation and emission reduction, locomotives and vehicles have gradually developed a new generation of energy-saving and environmentally friendly locomotives with lithium-ion power batteries as new power sources. However, lithium-ion batteries are inherently unsafe. Once abuse conditions such as overcharging, short circuit, and overheating occur, the battery may experience thermal runaway. If not controlled, it will lead to battery fires and even locomotive fires. Therefore, locomotive and vehicle lithium-ion power battery fire prevention and control systems are applied.

[0003] The fire prevention and control system for power batteries for rail transit is divided into prevention and control based on the working principle. Prevention is to cool down the battery when the temperature exceeds the normal operating temperature but before it reaches the thermal runaway temperature to prevent accidents before they happen; control is to suppress open flames after the battery temperature exceeds the thermal runaway temperature to prevent the spread of open flames.

[0004] The fire prevention and control performance verification method for the power battery fire prevention and control system for rail transit was standardized in the group standard TJ / JW 001C-2024 "Interim Technical Conditions for Locomotive Fire Monitoring Subsystem of Locomotive Onboard Safety Protection System (6A System)" compiled by the Locomotive and Rolling Stock Research Institute of the China Academy of Railway Sciences in August 2024. However, the current test platform cannot complete the fire prevention and control performance test of the power battery fire prevention and control system in accordance with the above standards. Summary of the invention

[0005] The present invention discloses a power battery fire prevention and control system test platform to overcome the above technical problems.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A power battery fire prevention and control system test platform, including: a heating plate, a signal acquisition module, an image acquisition and recognition module, a test platform host, a safety monitoring module, and a 1# electric ignition switch;

[0008] The heating plate is used to heat the power battery when a temperature reduction test or a fire extinguishing test is performed on the power battery fire prevention and control system using the test platform;

[0009] The signal acquisition module is used to obtain the input current and the input voltage of the heating plate in real time when the power battery is heated in the cooling test / fire extinguishing test of the power battery fire prevention and control system; when the cooling test / fire extinguishing test is performed on the power battery fire prevention and control system, obtain the release pressure of the cooling medium / fire extinguishing medium at the nozzle of the fire cylinder when releasing the cooling medium / fire extinguishing medium and the flow rate of the cooling medium / fire extinguishing medium; after the cooling test / fire extinguishing test of the power battery fire prevention and control system is completed, obtain the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage of the area where the power battery is located;

[0010] The image acquisition and recognition module is used to obtain a monitoring image of the power battery when performing a fire extinguishing test on the power battery fire prevention and control system, so as to determine whether there is an open fire area in the monitoring image of the power battery based on the range of hue values, the range of saturation values ​​and the range of brightness values ​​of the monitoring image of the power battery;

[0011] The test platform host is used to obtain the actual heating power of the heating plate in real time according to the input current and the input voltage of the heating plate, so that when the power battery fire prevention and control system is subjected to a cooling test, the temperature change at the battery pole ear satisfies the temperature rise curve, and after the power battery is heated, the power battery is cooled down, so as to determine the cooling performance of the power battery fire prevention and control system according to the power battery temperature drop rate, the cooling medium release pressure, the cooling medium flow change and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the cooling performance of the power battery fire prevention and control system; and when the power battery fire prevention and control system is subjected to a fire extinguishing test, the heating power of the heating plate is set to the preset fire extinguishing test heating plate power, such as Figure 3 As shown; and after the power battery is heated, the 1# ignition switch is used to ignite, so that when there is an open fire area in the monitoring image of the power battery, the power battery area is extinguished, so as to determine the fire extinguishing performance of the battery fire prevention and control system according to the open fire suppression situation, the release pressure of the fire extinguishing medium, the change of the fire extinguishing medium flow rate and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the fire extinguishing performance of the power battery fire prevention and control system;

[0012] The safety monitoring module is used to determine whether the test personnel can enter the test area for subsequent operations according to the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage after determining the cooling performance of the power battery fire prevention and control system or determining the fire extinguishing performance of the power battery fire prevention and control system.

[0013] Further, it also includes strain gauges;

[0014] The strain gauge is used to obtain the deformation of the safety valve of the power battery, so as to determine whether the safety valve of the power battery is open through the deformation of the safety valve of the power battery after a cooling test or a fire extinguishing test is performed on the power battery fire prevention and control system.

[0015] Furthermore, the test platform also includes an auxiliary function module;

[0016] The auxiliary function module includes a report automatic generation module and a test problem recording module;

[0017] The automatic report generation module is used to obtain the test platform experiment report based on a preset report template;

[0018] The test question recording module is used to automatically record the start time, stop time and test process data of the test.

[0019] Furthermore, the method for conducting a cooling test on the power battery fire prevention and control system is as follows:

[0020] S11: The power battery fire prevention and control system conducts a self-test after being powered on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S12 is executed;

[0021] S12: starting the heating plate to heat the power battery, obtaining the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then making the temperature rise at the battery tab meet the temperature rise curve based on the PID controller;

[0022] S13: When the temperature at the battery tab reaches 80° C. within 30 minutes, and the temperature at the battery tab remains at 80° C. for more than 10 seconds, the heating plate is turned off and the heating plate is moved to a designated position within 30 seconds, so that the heating plate is away from the power battery;

[0023] S14: Release the cooling medium. If the cooling medium release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds and the flow rate of the cooling medium is greater than 0.1m / s, and the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, if the temperature of the power battery does not exceed 82 degrees and continues to decrease at this time, the cooling performance of the power battery fire prevention and control system is good.

[0024] Furthermore, the temperature rise curve is expressed by the following formula:

[0025]

[0026] Where: t is the heating time; T0 is the initial temperature at the battery tab; T is the real-time temperature at the battery tab during the cooling test.

[0027] Furthermore, the method for conducting a fire extinguishing test on the power battery fire prevention and control system is as follows:

[0028] S21: The power battery fire prevention and control system conducts a self-test after power-on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S22 is executed;

[0029] S22: Start the heating plate to heat the power battery, obtain the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then make the heating power of the heating plate the preset fire extinguishing test heating plate power based on the PID controller;

[0030] S23: When the image acquisition and recognition module can emit a life signal and the pressure relief valve of the power battery can be opened normally, the heating plate is turned off and reaches a designated position within 30 seconds, so that the heating plate is away from the power battery;

[0031] S24: starting the 1# electric ignition switch, and acquiring the monitoring image of the power battery, and determining whether there is an open fire area in the monitoring image of the power battery;

[0032] S25: If the power battery temperature exceeds 150°C or the time of the open fire area in the monitoring image of the power battery reaches 3 minutes, the fire extinguishing agent is released; when the fire extinguishing agent release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds, and the flow rate of the fire extinguishing agent is greater than 0.1m / s, and the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, the fire extinguishing agent is successfully released through the fire cylinder;

[0033] S26: If within 30 seconds of releasing the fire extinguishing agent, there is no open fire area in the monitoring image of the power battery, and the fire cylinder generates a low-pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, then the fire extinguishing performance of the power battery fire prevention and control system is good.

[0034] Furthermore, after S26, it also includes: within 30 minutes after the open flame area no longer exists in the monitoring image of the power battery, turning on the 2# electric ignition switch every 3 minutes and continuing for 5 seconds.

[0035] Furthermore, the hue value of the monitoring image of the power battery ranges from 30 to 60°, the saturation value ranges from 28 to 100, and the brightness value ranges from 155 to 255.

[0036] Furthermore, the method for determining whether there is an open fire area in the monitoring image of the power battery is as follows:

[0037] S31: preprocessing the monitoring image of the power battery by using a median filtering method to obtain an R value, a G value, and a B value in the preprocessed monitoring image;

[0038] S32: adjusting the color of the preprocessed monitoring image according to the R value, G value, and B value in the preprocessed monitoring image, obtaining the R value, G value, and B value in the monitoring image after the color adjustment, so as to obtain the monitoring image after the color adjustment;

[0039] S33: obtaining a grayscale co-occurrence matrix of the color-adjusted monitoring image to obtain the contrast and uniformity of the color-adjusted monitoring image, and determining whether there is a white smoke area in the monitoring image of the power battery; when there is a white smoke area in the monitoring image of the power battery, obtaining a non-white smoke area in the monitoring image of the power battery;

[0040] S34: According to the color-adjusted monitoring image, the hue, saturation and brightness of the color-adjusted monitoring image are obtained through the HSI color space method, so as to determine whether there is an open flame area in the non-white smoke area in the monitoring image of the power battery based on the hue value range, saturation value range and brightness value range of the monitoring image of the power battery.

[0041] Furthermore, in the S24, after starting the 1# electric ignition switch, it also includes obtaining the input current and input voltage of the 1# electric ignition switch to obtain the ignition energy of the 1# electric ignition switch, so that in the fire extinguishing test of the power battery fire prevention and control system, after the 1# electric ignition switch fails to ignite, the test personnel can analyze the cause of the test failure according to the ignition energy.

[0042] Beneficial effect: A power battery fire prevention and control system test platform of the present invention performs performance tests on power battery fire prevention and control systems for rail transit by considering the two stages of prevention and control. The test platform host of the present invention can provide a maximum degree of automated fire extinguishing performance test process, 100% avoiding human judgment / intervention, and providing an effective means for testing and verifying lithium-ion power battery fire prevention and control systems for rail transit, effectively solving the problem of battery fires and even locomotive vehicle fires caused by thermal runaway of the battery due to overcharging, short circuit, overheating, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 It is the overall block diagram of the fire extinguishing performance testing platform in the present invention.

[0045] Figure 2 It is a temperature variation curve diagram of the battery tab in the temperature drop test in the embodiment of the present invention;

[0046] Figure 3 It is a schematic diagram of a power variation curve of a heating plate in a fire extinguishing test in an embodiment of the present invention;

[0047] Figure 4 A schematic diagram of the relationship between the power battery safety valve and the strain gauge when the safety valve is opened and closed in an embodiment of the present invention;

[0048] Figure 5 It is a schematic diagram of the communication module flow in an embodiment of the present invention;

[0049] Figure 6 A schematic diagram of an output control module in an embodiment of the present invention;

[0050] Figure 7 A schematic diagram of an image acquisition and recognition module in an embodiment of the present invention;

[0051] Figure 8 A control circuit for an ignition energy control system in an embodiment of the present invention;

[0052] Fig. 9 A schematic diagram of a security monitoring module in an embodiment of the present invention;

[0053] Fig.10 is a schematic diagram of an auxiliary function module in an embodiment of the present invention;

[0054] Fig.11 It is a schematic diagram of a cooling test process of a power battery fire prevention and control system in an embodiment of the present invention;

[0055] Fig.12 It is a schematic diagram of the fire extinguishing test process of the power battery fire prevention and control system in an embodiment of the present invention;

[0056] Fig.13 Schematic diagram of a sensor signal acquisition module in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] This embodiment introduces a power battery fire prevention and control system test platform, which is mainly used for lithium-ion battery fire extinguishing performance test. Figure 1 As shown, it includes: a heating plate, a signal acquisition module, an image acquisition and recognition module, a test platform host, a safety monitoring module, and a 1# electric ignition switch;

[0059] The heating plate is used to heat the power battery when a temperature reduction test or a fire extinguishing test is performed on the power battery fire prevention and control system using the test platform;

[0060] The signal acquisition module is used to obtain the input current and input voltage of the heating plate in real time when the power battery is heated in the cooling test / fire extinguishing test of the power battery fire prevention and control system; to obtain the release pressure of the cooling medium / fire extinguishing medium at the nozzle of the fire cylinder and the flow rate of the cooling medium / fire extinguishing medium when releasing the cooling medium / fire extinguishing medium when the cooling test / fire extinguishing test of the power battery fire prevention and control system is performed; after the cooling test / fire extinguishing test of the power battery fire prevention and control system is completed, the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage of the area where the power battery is located are obtained; such as Fig.13 shown.

[0061] Specifically, the signal acquisition module in this embodiment includes a current sensor, a voltage sensor, a pressure sensor, and a flow meter; the current sensor is used to obtain the input current of the heating plate; the voltage sensor is used to obtain the input voltage of the heating plate; the pressure sensor is used to obtain the cooling medium release pressure at the nozzle when releasing the cooling medium when the power battery fire prevention and control system is subjected to a cooling test, and to obtain the fire extinguishing agent release pressure at the nozzle when releasing the fire extinguishing agent when the power battery fire prevention and control system is subjected to a fire extinguishing test; the flow meter is used to obtain the cooling medium flow at the nozzle when releasing the cooling medium when the power battery fire prevention and control system is subjected to a cooling test, and to obtain the fire extinguishing agent flow at the nozzle when releasing the fire extinguishing agent when the power battery fire prevention and control system is subjected to a fire extinguishing test.

[0062] The image acquisition and recognition module is used to obtain the monitoring image of the power battery when performing a fire extinguishing test on the power battery fire prevention and control system, so as to determine whether there is an open fire area in the monitoring image of the power battery based on the range of hue values, saturation values ​​and brightness values ​​of the monitoring image of the power battery; the specific flow chart is as follows: Figure 7 As shown; the image acquisition and recognition module in this embodiment is a conventional camera device.

[0063] Preferably, in this embodiment, the hue value of the monitoring image of the power battery ranges from 30 to 60°, the saturation value ranges from 28 to 100, and the brightness value ranges from 155 to 255.

[0064] The test platform host is used to obtain the actual heating power of the heating plate in real time according to the input current and the input voltage of the heating plate, so that when the power battery fire prevention and control system is subjected to a cooling test, the temperature change at the battery pole ear satisfies the temperature rise curve, and after the power battery is heated, the power battery is cooled, so that the cooling performance of the power battery fire prevention and control system is determined according to the power battery temperature drop rate, the cooling medium release pressure, the cooling medium flow change, and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the cooling performance of the power battery fire prevention and control system; and when the power battery fire prevention and control system is subjected to a fire extinguishing test, the heating power of the heating plate is set to the preset fire extinguishing test heating plate power; and after the power battery is heated, the 1# ignition switch is used to ignite, so that when there is an open fire area in the monitoring image of the power battery, the power battery area is extinguished, so that the fire extinguishing performance of the battery fire prevention and control system is determined according to the open fire suppression situation, the fire extinguishing medium release pressure, the fire extinguishing medium flow change, and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the fire extinguishing performance of the power battery fire prevention and control system;

[0065] Specifically, the open flame suppression situation in this embodiment can be judged based on the reduction rate of the open flame area in the monitoring image of the power battery. The implementation method is the existing technology in the field and will not be described in detail here.

[0066] The safety monitoring module is used to determine whether the test personnel can enter the test area for subsequent operations according to the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage after determining the cooling performance of the power battery fire prevention and control system or the fire extinguishing performance of the power battery fire prevention and control system. Fig. 9 shown.

[0067] Specifically, in this embodiment, the safety monitoring module detects the concentration of toxic and harmful gases (CO) and combustible gases (H2) through gas concentration sensors, and the safety concentration threshold of CO is set to 20ppm, and the safety concentration threshold of H2 is set to 5000ppm; the battery temperature and ambient temperature are detected by thermocouples, and the temperature threshold is set to 25°C; the heating plate temperature and relay status are checked to determine whether the heating plate is in the off state; the electric ignition output state is determined by the real-time measurement of the electric ignition energy; the image collected by the camera determines whether the battery is still continuing to produce thermal runaway and form white smoke; the voltage sensor determines whether the test environment is electrified. When the above conditions meet the safety requirements at the same time, personnel can enter the laboratory for subsequent operations.

[0068] Preferably, the test platform of this embodiment also includes a strain gauge; the strain gauge is used to obtain the deformation of the safety valve of the power battery, so as to determine whether the safety valve of the power battery is open through the deformation of the safety valve of the power battery after a cooling test is performed on the power battery fire prevention and control system or a fire extinguishing test is performed on the power battery fire prevention and control system.

[0069] Preferably, the strain gauge is arranged on the safety valve. Once the safety valve is opened, the strain gauge bends and deforms. The threshold value of the strain gauge is set to 0.5 mm. Figure 4 As shown;

[0070] Specifically, after there is no open flame area in the monitoring image of the power battery, the deformation state of the battery safety valve is collected through the strain gauge. If the battery does not reignite and other battery safety valves are not opened and the temperature of other batteries does not exceed 90°C, the fire prevention and control system has good anti-reignition performance and timely action, the fire has not spread to affect other surrounding batteries, and the fire extinguishing test is passed. At the same time, the laboratory environment is monitored for safety. After it is judged to be safe, relevant experimental personnel can enter for subsequent processing.

[0071] Specifically, the test platform of this embodiment also includes a communication module; the communication module is used to transmit the fault signal of the power battery fire prevention and control system to the test platform host, and at the same time send a control signal to the fire controller of the power battery fire prevention and control system, so that when the power battery fire prevention and control system is subjected to a cooling test, the fire cylinder of the fire controller is driven to release the cooling medium, and when the power battery fire prevention and control system is subjected to a fire extinguishing test, the fire cylinder of the fire controller is driven to release the fire extinguishing medium.

[0072] The communication module communicates with the fire controller via Ethernet. Figure 5As shown: the fire controller uploads the fault and status signals of the power battery fire prevention and control system to the test platform host. The fault signals include: system fault (fire controller fault, fire detector fault); the status signals include: CO concentration and temperature collected by the fire detector, solenoid valve drive signal, and cylinder low pressure alarm signal; among them, when a fault signal is generated, the fire extinguishing performance test needs to be stopped; through the CO concentration and temperature, determine whether the test personnel can enter the test area for subsequent operations after the experiment; through the feedback after the solenoid valve is actuated, judge whether the solenoid valve of the fire cylinder is actuated; the low pressure alarm signal of the fire cylinder is an important basis for determining whether the state of the fire cylinder is normal, and an important basis for determining whether the fire extinguishing agent in the fire cylinder is released.

[0073] Specifically, the test platform of this embodiment also includes a 2# electric ignition switch. In order to ensure smooth ignition, the 1# electric ignition switch is close to the power battery. In this embodiment, the distance between the 1# electric ignition switch and the power battery is set to be less than 5 cm. In this way, after the open flame is generated, the 1# electric ignition switch will be damaged by the open flame. Therefore, after the fire extinguishing test is completed, the 2# electric ignition switch is used for ignition to verify whether the power battery fire prevention and control system can reignite.

[0074] Preferably, the test platform also includes an auxiliary function module; the auxiliary function module includes an automatic report generation module and a test problem recording module; the automatic report generation module is used to obtain the test platform experiment report based on a preset report template; the test problem recording module is used to automatically record the start time, stop time and test process data of the test. Subsequent experimenters analyze the data to form cause analysis and rectification optimization plans and effects, thereby effectively improving the success rate of the test, such as Fig.10 shown.

[0075] Preferably, if Fig.11 As shown, the method for conducting a cooling test on the power battery fire prevention and control system is as follows:

[0076] S11: The power battery fire prevention and control system conducts a self-test after being powered on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S12 is executed;

[0077] Specifically, during the system startup self-test, if the fire cylinder generates a low-pressure alarm signal, it means that the fire cylinder of the power battery fire prevention and control system cannot work normally and the test is stopped.

[0078] S12: starting the heating plate to heat the power battery, obtaining the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then making the temperature rise at the battery tab meet the temperature rise curve based on the PID controller;

[0079] Preferably, the temperature rise curve is expressed by the following formula:

[0080]

[0081] Wherein: t is the heating time, unit is s; T0 is the initial temperature at the battery ear, unit is ℃; T is the real-time temperature at the battery ear during the cooling test, unit is ℃.

[0082] Specifically, in this embodiment, in order to ensure that the battery tab temperature gradually reaches equilibrium and approaches 80°C within 30 minutes during the cooling test, the tab temperature variation curve is set as follows: Figure 2 As shown,

[0083] S13: When the temperature at the battery tab reaches 80° C. within 30 minutes, and the temperature at the battery tab remains at 80° C. for more than 10 seconds, the heating plate is turned off and the heating plate is moved to a designated position within 30 seconds, so that the heating plate is away from the power battery;

[0084] Specifically, in this embodiment, when the power battery fire prevention and control system is powered on and the self-check meets the set standard for performance testing, the electric push rod is used to transport the heating plate to the power battery to heat the power battery. When the temperature at the battery ear reaches 80 degrees within 30 minutes of heating and the maintenance time exceeds 10 seconds, it is considered that the power battery temperature is too high and needs to be cooled. If it does not reach 80 degrees within 30 minutes, the test is stopped, the heating plate is replaced and the test is repeated; if the heating plate temperature reaches 80 degrees within 30 minutes, but does not maintain for more than 10 seconds, the heating plate is continued to be heated until the phenomenon of maintaining 80 degrees for more than 10 seconds appears, and then the test is continued. At this time, the heating plate is turned off, and the electric push rod is used to keep the heating plate away from the power battery, and the heating plate reaches the specified position within 30 seconds to prevent the temperature of the heating plate from affecting the cooling of the power battery. In this embodiment, if the electric push rod does not reach the specified position within 30 seconds, the test of the power battery fire prevention and control system fails, the electric push rod is replaced, and the test is repeated.

[0085] Specifically, in this embodiment, the test platform host can heat the heating plate to 80 degrees and then stabilize it at 80 degrees.

[0086] S14: Release the cooling medium. If the cooling medium release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds and the flow rate of the cooling medium is greater than 0.1m / s, and the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, if the temperature of the power battery does not exceed 82 degrees and continues to decrease at this time, the cooling performance of the power battery fire prevention and control system is good.

[0087] Specifically, in this embodiment, the release pressure of the cooling medium at the nozzle is obtained by a pressure sensor, and the flow rate of the cooling medium at the nozzle is measured by a flow meter; if the pressure sensor reading exceeds the preset value of 0.1MPa and the flow sensor reading is greater than 0.1 m / s within 10 seconds, it is considered that the cooling medium is successfully released from the nozzle into the protection space, and if the system self-checks without faults and the low-pressure alarm signal is uploaded, it is considered that the test equipment is in good condition during the entire test process. Among them, since the cooling medium / fire extinguishing agent is released under the drive of high-pressure nitrogen (about 2.5-4.2MPa) in the fire cylinder, once the fire extinguishing agent is released, it means that the high-pressure nitrogen is also released from the cylinder, and the pressure in the cylinder will drop from 2.5-4.2MPa to 0MPa, and the low-pressure alarm that monitors the pressure in the cylinder will generate an alarm signal and upload it, so the low-pressure alarm signal appears 10s after the fire extinguishing agent is released.

[0088] Specifically, when the battery temperature does not exceed 82°C and shows an overall downward trend, the cooling test is passed. At the same time, the laboratory environment is monitored for safety. Only after the safety monitoring module determines that the laboratory environment is safe can relevant experimental personnel enter for subsequent processing.

[0089] Preferably, if Fig.12 As shown, the method for conducting a fire extinguishing test on a power battery fire prevention and control system is as follows:

[0090] S21: The power battery fire prevention and control system conducts a self-test after power-on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S22 is executed;

[0091] S22: Start the heating plate to heat the power battery, obtain the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then make the heating power of the heating plate the preset fire extinguishing test heating plate power based on the PID controller;

[0092] Specifically, the input current and input voltage of the heating plate are obtained in real time to obtain the real-time power of the heating plate, and then the heating power of the heating plate is made constant to the preset fire extinguishing test heating plate power (500W) based on the PID controller;

[0093] Specifically, in order to ensure that the power of the heating plate remains constant at the preset fire extinguishing test heating plate power during the fire extinguishing test, the input voltage and input current of the heating plate are collected in real time to obtain the real-time power of the heating plate, and compared with the power setting value. The power of the heating plate is adjusted in real time by means of a PID controller. The corresponding relationship between the heating plate power and the rated capacity of the battery is: W=2.5E, where W is the heating plate power and E is the rated capacity of the battery.

[0094] S23: When the image acquisition and recognition module can emit a life signal and the pressure relief valve of the power battery can be opened normally, the heating plate is turned off and reaches a designated position within 30 seconds, so that the heating plate is away from the power battery;

[0095] S24: starting the 1# electric ignition switch, and acquiring the monitoring image of the power battery, and determining whether there is an open fire area in the monitoring image of the power battery;

[0096] S25: If the power battery temperature exceeds 150°C or the time of the open fire area in the monitoring image of the power battery reaches 3 minutes, the fire extinguishing agent is released; when the fire extinguishing agent release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds, and the flow rate of the fire extinguishing agent is greater than 0.1m / s, it is considered that the fire extinguishing agent is successfully released from the nozzle into the protection space. At the same time, the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, then the fire extinguishing agent is successfully released through the fire cylinder;

[0097] S26: If within 30 seconds of releasing the fire extinguishing agent, there is no open fire area in the monitoring image of the power battery, and the fire cylinder generates a low-pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, then the fire extinguishing performance of the power battery fire prevention and control system is good. At this time, it is considered that the test equipment is in good condition during the entire test process and the test data is accurate.

[0098] Specifically, in this embodiment, if the pressure data does not exceed the preset value of 0.1MPa within 10 seconds, or the flow rate of the fire extinguishing agent is not greater than 0.1m / s, the fire prevention and control system fails and the fire extinguishing medium is not sprayed out from the nozzle. The cause needs to be found and the test needs to be repeated.

[0099] Preferably, in S24, after starting the 1# electric ignition switch, the step further includes obtaining the input current and input voltage of the 1# electric ignition switch to obtain the ignition energy of the 1# electric ignition switch, so that when the 1# electric ignition switch fails to ignite during the fire extinguishing test of the power battery fire prevention and control system, the ignition energy can be adjusted so that the ignition energy is sufficient to successfully ignite. The test personnel can analyze the cause of the test failure based on the ignition energy.

[0100] The control circuit of the ignition energy control system is as follows: Figure 8 As shown, the voltage and current at both ends of the ignition head can be read through the voltage sensor and the current sensor, and the ignition energy can be obtained by integrating the instantaneous voltage and current.

[0101]

[0102] Where: U t Indicates the input voltage of 1# electric ignition switch; I tIndicates the input current of the 1# electric ignition switch; t1 indicates the time when the 1# electric ignition switch starts ignition; t2 indicates the time when the 1# electric ignition switch ends ignition; E indicates the ignition energy;

[0103] The ignition energy control system of this embodiment is mainly composed of an ignition head, a power supply, a switch, a capacitor, a resistor, an inductor, and an IGBT. KM1 and KM3 are closed, the high-voltage trigger power supply charges the trigger capacitor group, and the low-voltage arc-following power supply charges the arc-following capacitor group. After charging is completed, KM2 is closed, the high-voltage trigger capacitor breaks down the gap between the electrodes of the ignition head, and the low-voltage arc-following capacitor group releases the stored voltage through the electrodes to complete the electrostatic spark discharge. By controlling the on-off of the IGBT, the purpose of shunting the electric energy of the arc-following capacitor group is achieved, thereby achieving precise control of the ignition energy. In addition, resistors R1 to R4 are current-limiting resistors. Since the main product of thermal runaway of lithium-ion power batteries is: H2, the ignition energy of hydrogen is 0.02MJ, and the ignition energy setting value in this experimental system is 0.2MJ / s. Once the real-time monitored ignition energy is lower than the set value, the ignition energy is adjusted by adjusting the on-off frequency of the IGBT until it reaches 0.1MJ.

[0104] Preferably, after S26, the method further includes: within 30 minutes after the open flame area no longer exists in the monitoring image of the power battery, turning on the 2# electric ignition switch every 3 minutes and continuing for 5 seconds.

[0105] Specifically, the image acquisition and recognition module of this embodiment needs to identify open flames, and then accurately capture the battery fire status and the open flame extinguishing status. It is necessary to perform smoke recognition first to avoid the interference of the dynamic characteristics of white smoke on the open flame judgment. At the same time, it serves as an important reference indicator for whether the test environment is safe after the test; it is necessary to identify life signals, that is, whether the camera has a flashing green light signal, and judge whether the camera can work reliably in the test environment by identifying the flashing green light in the environment, so as to carry out the next step of test operation.

[0106] Specifically, the image acquisition and recognition module of this embodiment is functionally divided into image acquisition, image preprocessing, color feature extraction, feature area preliminary judgment, fuzzy feature extraction, clustering feature extraction, motion feature extraction and area change feature extraction.

[0107] Preferably, the method for determining whether there is an open fire area in the monitoring image of the power battery is as follows:

[0108] S31: preprocessing the monitoring image of the power battery by using a median filtering method to obtain an R value, a G value, and a B value in the preprocessed monitoring image;

[0109] u(x,y)=med{f(xm,yn),m,n∈Q}

[0110] Where, (x, y) is the original image, u(x, y) is the processed image, Q is the two-dimensional rectangular template; med represents the median filter standard function; m represents the horizontal coordinate variable in the two-dimensional rectangular template; n represents the vertical coordinate variable in the two-dimensional rectangular template; f(xm, yn) represents the matrix transformation function;

[0111] S32: Adjust the color of the image through a color balancing algorithm. According to the R value, G value, and B value in the preprocessed monitoring image, adjust the color in the preprocessed monitoring image, obtain the R value, G value, and B value in the color-adjusted monitoring image, and obtain the color-adjusted monitoring image; the formula used is as follows:

[0112]

[0113] Where R0, G0, and B0 represent the R value, G value, and B value of the preprocessed image, respectively; R a , G a , B a They represent the R value, G value, and B value in the surveillance image after color adjustment, respectively. p1, p2, and p3 are all intermediate calculation parameters. Avi_R, Avi_G, and Avi_B represent the pixel means of the R value, G value, and B value in the RGB space of the surveillance image after color adjustment, respectively. Avi_M is the pixel mean of the grayscale image M obtained by projecting the RGB space of the surveillance image after color adjustment into the grayscale space.

[0114] S33: obtaining a gray level co-occurrence matrix of the monitoring image of the power battery to obtain the contrast and uniformity of the monitoring image of the power battery, and determining whether there is a white smoke area in the monitoring image of the power battery; when there is a white smoke area in the monitoring image of the power battery, obtaining a non-white smoke area in the monitoring image of the power battery;

[0115] Specifically, since a large amount of white smoke is generated during battery thermal runaway, the diffusion of smoke may interfere with the recognition of the motion features of the flame, so it is necessary to perform fuzziness extraction and clustering feature extraction on the smoke to distinguish smoke from open flames. This embodiment calculates the image fuzziness based on the gray level co-occurrence matrix of the image.

[0116] P(i,j)=|{((r,s),(t,v)):I(r,s)=i,I(t,v)=j}|

[0117] Where: P(i,j) represents the gray level co-occurrence matrix; r represents the horizontal coordinate of the i-th pixel; s represents the vertical coordinate of the i-th pixel; and i≠j; represents (the vertical coordinate of pixel 1); t represents the horizontal coordinate of the ji-th pixel; v represents the vertical coordinate of the j-th pixel; i and j both represent pixel indexes, and i≠j; I(r,s) represents the gray value of the i-th pixel; I(t,v) represents the gray value of the j-th pixel;

[0118] In this embodiment, the obtained co-occurrence matrix is ​​used to obtain the calculation formula of contrast and uniformity as follows:

[0119]

[0120] Where: CR represents contrast; HG represents uniformity;

[0121] In addition, this embodiment uses image edge energy ED as one of the criteria for measuring image clarity. The image is edge detected, and then the square of the edge difference value is statistically summed to obtain the value of image edge energy. Contrast CR, uniformity HG and edge energy ED are normalized. The lower the contrast, the higher the uniformity, and the smaller the edge energy, it means that there is smoke in the image. If the following conditions are met, it is considered that smoke has been generated in the area.

[0122] CR≤CR0-0.1,HG≥HG0+0.15,ED≤ED0-0.1

[0123] Wherein, CR0, HG0 and ED0 are the initial contrast, uniformity and image edge energy of the test, respectively. S34: According to the color-adjusted monitoring image, the hue, saturation and brightness of the color-adjusted monitoring image are obtained by the HSI color space method, so as to determine whether there is an open flame area in the non-white smoke area in the monitoring image of the power battery based on the range of hue values, the range of saturation values ​​and the range of brightness values ​​of the monitoring image of the power battery.

[0124] The formula for converting from RGB space to HSI space is as follows:

[0125]

[0126] In the formula: H represents hue; α represents the intermediate calculated value; S represents saturation; I represents brightness;

[0127] In this embodiment, after the battery catches fire, the hue H value of the open flame is 30-60°, the saturation S value is 28-100, and the brightness I value is 155-255.

[0128] The motion features are extracted through the maximum inter-class variance method.

[0129] σ2 (t)=w1(t)×w2(t)×(u1(t)-u2(t)) 2

[0130]

[0131] Where: 2 (t) represents the variance of two types of gray values; t represents the variable used to adjust the classification status of pixel gray values; w1(t) is the pixel value contained in C0; w2(t) is the pixel value contained in C1, u1(t) is the average gray value of all pixels in C0, and u2(t) is the average gray value of all pixels in C1; C0 represents the set of pixels with gray values ​​of 0 to t; C1 represents the set of pixels with gray values ​​of t+1 to L-1; T represents the maximum variance set; Arg represents the complex angular function; L represents the maximum number of image pixel values;

[0132] Specifically, the present embodiment further includes an output control module, which is used to control the power and temperature rise rate of the heating plate through a PID control method, control the action stroke of the electric push rod through feedback from a travel switch, and control the ignition energy of the igniter by controlling the on and off of the IGBT, such as Figure 6 shown.

[0133] Specifically, a specific completed fire prevention and control performance test process of a lithium-ion power battery fire prevention and control system in this embodiment includes:

[0134] 1) Cooling test:

[0135] a. Start the heating plate. When the temperature at the battery cell tab or the detector reaches 80°C and is maintained for more than 10 seconds, the fire suppression device automatically triggers the cooling action, disconnects the power supply of the temperature-controlled heating plate, starts the heating plate separation device to separate the battery cell from the heating plate, and the fire suppression device sprays perfluorohexanone medium into the cabinet;

[0136] b. Record the specified data within 30 minutes after the fire suppression device starts spraying.

[0137] 2) Fire extinguishing test:

[0138] a. Start the metal heating plate to heat the battery cells until thermal runaway occurs and the pressure relief valve opens, then disconnect the power supply of the metal heating plate.

[0139] b. Turn on the 1# high-voltage electric ignition device until an open flame appears. After the fire starts, it will continue to burn for 3 minutes or the temperature on the back of the heated battery cell exceeds 150°C (whichever is triggered first). Start the fire suppression device to spray perfluorohexanone medium into the battery cabinet;

[0140] c. Within 30 minutes after the open flame is extinguished, use the No. 2 electric ignition device in the battery cabinet to ignite once every 3 minutes, observe whether there is re-ignition in the battery cabinet, and record the temperature data of each temperature measuring point in the battery cabinet within the specified time.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power battery fire prevention and control system test platform, characterized in that: include: Heating plate, signal acquisition module, image acquisition and recognition module, test platform host, safety monitoring module, 1# electric ignition switch; The heating plate is used to heat the power battery when a temperature reduction test or a fire extinguishing test is performed on the power battery fire prevention and control system using the test platform; The signal acquisition module is used to obtain the input current and the input voltage of the heating plate in real time when the power battery is heated in the cooling test / fire extinguishing test of the power battery fire prevention and control system; when the cooling test / fire extinguishing test is performed on the power battery fire prevention and control system, obtain the release pressure of the cooling medium / fire extinguishing medium at the nozzle of the fire cylinder when releasing the cooling medium / fire extinguishing medium and the flow rate of the cooling medium / fire extinguishing medium; after the cooling test / fire extinguishing test of the power battery fire prevention and control system is completed, obtain the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage of the area where the power battery is located; The image acquisition and recognition module is used to obtain a monitoring image of the power battery when performing a fire extinguishing test on the power battery fire prevention and control system, so as to determine whether there is an open fire area in the monitoring image of the power battery based on the range of hue values, the range of saturation values ​​and the range of brightness values ​​of the monitoring image of the power battery; The test platform host is used to obtain the actual heating power of the heating plate in real time according to the input current and the input voltage of the heating plate, so that when the power battery fire prevention and control system is subjected to a cooling test, the temperature change at the battery pole ear satisfies the temperature rise curve, and after the power battery is heated, the power battery is cooled, so that the cooling performance of the power battery fire prevention and control system is determined according to the power battery temperature drop rate, the cooling medium release pressure, the cooling medium flow change and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the cooling performance of the power battery fire prevention and control system; and when the power battery fire prevention and control system is subjected to a fire extinguishing test, the heating power of the heating plate is the preset fire extinguishing test heating plate power, as shown in FIG3; and after the power battery is heated, the 1# ignition switch is used to ignite, so that when there is an open fire area in the monitoring image of the power battery, the power battery area is extinguished, so that the fire extinguishing performance of the battery fire prevention and control system is determined according to the open fire suppression situation, the fire extinguishing medium release pressure, the fire extinguishing medium flow change and the fault signal of the power battery fire prevention and control system, so as to comprehensively evaluate the fire extinguishing performance of the power battery fire prevention and control system; The safety monitoring module is used to determine whether the test personnel can enter the test area for subsequent operations according to the carbon monoxide concentration, hydrogen concentration, ambient temperature and ambient voltage after determining the cooling performance of the power battery fire prevention and control system or determining the fire extinguishing performance of the power battery fire prevention and control system.

2. A power battery fire prevention and control system test platform according to claim 1, characterized in that: It also includes strain gauges; The strain gauge is used to obtain the deformation of the safety valve of the power battery, so as to determine whether the safety valve of the power battery is open through the deformation of the safety valve of the power battery after a cooling test or a fire extinguishing test is performed on the power battery fire prevention and control system.

3. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The test platform also includes an auxiliary function module; The auxiliary function module includes a report automatic generation module and a test problem recording module; The automatic report generation module is used to obtain the test platform experiment report based on a preset report template; The test question recording module is used to automatically record the start time, stop time and test process data of the test.

4. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The method for conducting a cooling test on the power battery fire prevention and control system is as follows: S11: The power battery fire prevention and control system conducts a self-test after being powered on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S12 is executed; S12: starting the heating plate to heat the power battery, obtaining the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then making the temperature rise at the battery tab meet the temperature rise curve based on the PID controller; S13: When the temperature at the battery tab reaches 80° C. within 30 minutes, and the temperature at the battery tab remains at 80° C. for more than 10 seconds, the heating plate is turned off and the heating plate is moved to a designated position within 30 seconds, so that the heating plate is away from the power battery; S14: Release the cooling medium. If the cooling medium release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds and the flow rate of the cooling medium is greater than 0.1m / s, and the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, if the temperature of the power battery does not exceed 82 degrees and continues to decrease at this time, the cooling performance of the power battery fire prevention and control system is good.

5. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The temperature rise curve is expressed by the following formula: Where: t is the heating time; T0 is the initial temperature at the battery tab; T is the real-time temperature at the battery tab during the cooling test.

6. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The method for conducting fire extinguishing test on power battery fire prevention and control system is as follows: S21: The power battery fire prevention and control system conducts a self-test after power-on. If there is no fault in the system and there is no low-pressure alarm signal from the fire cylinder of the power battery fire prevention and control system, S22 is executed; S22: Start the heating plate to heat the power battery, obtain the input current and input voltage of the heating plate in real time to obtain the actual heating power of the heating plate, and then make the heating power of the heating plate the preset fire extinguishing test heating plate power based on the PID controller; S23: When the image acquisition and recognition module can emit a life signal and the pressure relief valve of the power battery can be opened normally, the heating plate is turned off and reaches a designated position within 30 seconds, so that the heating plate is away from the power battery; S24: starting the 1# electric ignition switch, and acquiring the monitoring image of the power battery, and determining whether there is an open fire area in the monitoring image of the power battery; S25: If the power battery temperature exceeds 150°C or the time of the open fire area in the monitoring image of the power battery reaches 3 minutes, the fire extinguishing agent is released; when the fire extinguishing agent release pressure at the nozzle of the fire cylinder exceeds 0.1MPa within 10 seconds, and the flow rate of the fire extinguishing agent is greater than 0.1m / s, and the fire cylinder generates a low pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, the fire extinguishing agent is successfully released through the fire cylinder; S26: If within 30 seconds of releasing the fire extinguishing agent, there is no open fire area in the monitoring image of the power battery, and the fire cylinder generates a low-pressure alarm signal and the power battery fire prevention and control system has no self-test fault signal, then the fire extinguishing performance of the power battery fire prevention and control system is good.

7. A power battery fire prevention and control system test platform according to claim 8, characterized in that: After S26, the method further includes: within 30 minutes after the open flame area no longer exists in the monitoring image of the power battery, turning on the 2# electric ignition switch every 3 minutes and continuing for 5 seconds.

8. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The hue value of the monitoring image of the power battery ranges from 30 to 60°, the saturation value ranges from 28 to 100, and the brightness value ranges from 155 to 255.

9. A power battery fire prevention and control system test platform according to claim 1, characterized in that: The method for determining whether there is an open fire area in the monitoring image of the power battery is as follows: S31: preprocessing the monitoring image of the power battery by using a median filtering method to obtain an R value, a G value, and a B value in the preprocessed monitoring image; S32: adjusting the color of the preprocessed monitoring image according to the R value, G value, and B value in the preprocessed monitoring image, obtaining the R value, G value, and B value in the monitoring image after the color adjustment, so as to obtain the monitoring image after the color adjustment; S33: Obtaining a grayscale co-occurrence matrix of the color-adjusted monitoring image to obtain contrast and uniformity of the color-adjusted monitoring image, and determining whether there is a white smoke area in the monitoring image of the power battery; When there is a white smoke area in the monitoring image of the power battery, obtaining a non-white smoke area in the monitoring image of the power battery; S34: According to the color-adjusted monitoring image, the hue, saturation and brightness of the color-adjusted monitoring image are obtained through the HSI color space method, so as to determine whether there is an open flame area in the non-white smoke area in the monitoring image of the power battery based on the hue value range, saturation value range and brightness value range of the monitoring image of the power battery.

10. A power battery fire prevention and control system test platform according to claim 4, characterized in that: In the S24, after starting the 1# electric ignition switch, it also includes obtaining the input current and input voltage of the 1# electric ignition switch to obtain the ignition energy of the 1# electric ignition switch, so that in the fire extinguishing test of the power battery fire prevention and control system, after the 1# electric ignition switch fails to ignite, the test personnel can analyze the cause of the test failure according to the ignition energy.

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