Electric bicycle fire simulation test method and system

Abstract

The invention provides an electric bicycle fire simulation test method and system. The method comprises the following steps: heating a battery of a vehicle in a state that the whole vehicle is electrified, and collecting video information of the whole test process; in the whole test process, the voltage, the temperature value and the temperature rise rate of the triggered single battery in the battery and smoke information in the battery compartment are continuously collected; when thermal runaway of the battery occurs, stopping heating, and recording the time and the temperature of the battery; according to the video information and smoke information in the battery compartment, identifying the moment when smoke appears; identifying the moment when open fire appears according to the video information; and calculating the time difference between the smoke and the thermal runaway, and the time difference between the flame and the thermal runaway. Data support and technical support can be provided for developing a charging scene fire recognition system, and meanwhile a foundation is laid for later electric bicycle fire tracing and emergency fire extinguishing scheme research.

Description

Technical Field

[0001] The invention relates to the field of electric bicycle fire tests, and in particular to an electric bicycle fire simulation test method and system. Background Art

[0002] In recent years, electric bicycle fires have emerged one after another, and fire safety issues have attracted great attention from all walks of life. Analyzing the characteristics of electric bicycle fires through simulation tests is of great significance for the design, early warning, protection, and treatment of electric bicycle fire safety. However, the current electric bicycle fire simulation tests still have the following problems:

[0003] 1. Currently, there is no systematic quantitative analysis method for the characteristics of electric bicycle fires.

[0004] 2. Fire characteristic analysis mainly relies on human observation, which is subject to human bias. In addition, due to the certain danger of the fire process, it is impossible to accurately measure the flame characteristic parameters such as the flame height and diameter at each stage.

[0005] 3. The current test method for electric bicycle fire simulation is relatively simple and cannot provide good guidance for fire simulation tests.

[0006] 4. The current electric bicycle fire simulation test is mainly at the practical application level, and cannot provide detailed data support and technical support for the development of fire identification systems in charging scenarios, fire extinguishing methods, and fire source tracing.

[0007] 5. The current electric bicycle fire simulation methods are relatively scattered, and it is impossible to systematically integrate the entire fire test process and data. Summary of the invention

[0008] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the present invention is to provide an electric bicycle fire simulation test method and system.

[0009] In order to achieve the above-mentioned object of the present invention, the present invention provides a fire simulation test method for an electric bicycle, comprising the following steps:

[0010] When the vehicle is powered on, the battery of the vehicle is heated and video information of the entire test process is collected;

[0011] During the entire test process, the voltage, temperature value and temperature rise rate of the triggered single cells in the battery, as well as the smoke information in the battery compartment are continuously collected;

[0012] When the battery experiences thermal runaway, stop heating and record the time and battery temperature.

[0013] Identify the moment when smoke appears based on the video information and the smoke information in the battery compartment;

[0014] identifying the moment when an open flame appears based on the video information;

[0015] Calculate the time difference between the appearance of smoke and thermal runaway, and the time difference between the appearance of flame and thermal runaway.

[0016] Optionally, when the following a and c, or b and c, occur, it is determined that the battery has thermal runaway:

[0017] a) The triggered single cell produces a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0018] b) The temperature of the triggered single battery reaches the maximum operating temperature specified by the manufacturer;

[0019] c) The temperature change rate of the triggered single battery dT / dt ≥ 1°C / s and lasts for more than 3s.

[0020] Optionally, when the temperature of the triggered single cell differs from the temperature alarm threshold of the battery BMS by a set temperature value, the heating power is reduced or the heating is stopped until the temperature gradually rises to the temperature alarm threshold, and the BMS alarm information and the on-board alarm hardware and function response are recorded;

[0021] The vehicle's battery is then heated until it experiences thermal runaway.

[0022] Optionally, establish a spatial coordinate system under the viewing angle of a video camera that collects video information, and take a pre-test photo;

[0023] Set up several temperature sensors to collect temperature information of the vehicle and its surroundings in real time during the test;

[0024] Set up a thermal imager, fuse the spatial coordinates of the thermal image into the spatial coordinate system of the video camera, and collect the thermal imaging information of the experimental field in real time during the test;

[0025] Analyze in real time the highest temperature value in the temperature data collected by the temperature sensor and the thermal imager in each fixed time interval after the start of the test, and record its position;

[0026] If the highest temperature is collected by a temperature sensor, record the location of the temperature sensor. If the highest temperature is recorded by a thermal imager, mark the location through thermal imaging and record the coordinates of the marked location. Mark the location of the highest temperature and the corresponding time on the photo before the test.

[0027] After the test, the highest temperature point location and the dynamic change video of the value are automatically generated on the photo taken before the test.

[0028] Optionally, a height ruler and a horizontal ruler are set in the test field, and the height and width of the flame are collected by the video camera to identify changes in flame shape characteristics in real time, and store pictures of the maximum flame width and highest height within each set time period after the flame appears.

[0029] Optionally, the calculation steps for the flame height and width are:

[0030] Calculate the number of horizontal ruler pixels n1 and height ruler pixels n2 in the image captured by the video camera, as well as the number of flame width pixels n3 and flame height pixels n4 in the corresponding image, and calculate the flame width and height by the following formula:

[0031] Flame width L = a × n3

[0032] n1

[0033] Flame height H = b × n4,

[0034] n2

[0035] Among them, a is the length of the horizontal scale and b is the length of the height scale.

[0036] The present invention also proposes an electric bicycle fire simulation test system, comprising a heating device for heating a vehicle battery, a battery temperature sensor arranged on a triggered battery cell, a voltage acquisition module for collecting the voltage of the battery cell, a smoke sensor arranged in a vehicle battery compartment, a video camera arranged in a test field, and a processing module;

[0037] The battery temperature sensor, voltage acquisition module, smoke sensor, and video camera are respectively connected to the processing module, and send the corresponding information collected to the processing module. The processing module is connected to the heating device control to control the opening and closing of the heating device;

[0038] The processing module performs an electric bicycle fire simulation test according to the above-mentioned electric bicycle fire simulation test method.

[0039] The present invention also proposes an electric bicycle fire simulation test system, comprising a heating device for heating a vehicle battery, a battery temperature sensor arranged on a heated battery cell, a plurality of field temperature sensors arranged on a vehicle body and around the vehicle, a voltage acquisition module for collecting the voltage of the battery cell, a smoke sensor arranged in a vehicle battery compartment, a video camera arranged in a test field, a thermal imager, and a processing module;

[0040] The battery temperature sensor, the field temperature sensor, the voltage acquisition module, the smoke sensor, the video camera, and the thermal imager are respectively connected to the processing module, and the corresponding information collected by them is sent to the processing module. The processing module is connected to the heating device control to control the opening and closing of the heating device;

[0041] The processing module performs an electric bicycle fire simulation test according to the above-mentioned electric bicycle fire simulation test method.

[0042] Optionally, several of the in-field temperature sensors are respectively arranged on the left and right handlebars of the vehicle, the saddle, the storage box, and the positions of the heart and head when a person is driving the vehicle.

[0043] The beneficial effects of the present invention are as follows: the present invention provides a systematic quantitative analysis method for the fire characteristics of electric bicycles, and can accurately simulate the time difference between thermal runaway of the battery of an electric bicycle and the appearance of smoke, as well as the time difference between thermal runaway and the appearance of flames; the change in the maximum temperature during the entire test process and the change in the position of the maximum temperature point can be accurately obtained; the flame characteristic parameters can be accurately measured, such as the flame height and diameter at each stage; data support and technical support can be provided for the development of a fire identification system for charging scenarios, and also lays the foundation for later research on the source tracing and emergency fire extinguishing plans for electric bicycle fires.

[0044] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0046] Figure 1 It is a schematic diagram of the distribution of video cameras, thermal imaging cameras, and heat flow meters in the experimental field;

[0047] Figure 2 is a schematic diagram of the location of the heating device;

[0048] Figure 3 and Figure 4 It is a schematic diagram of the distribution of temperature sensors in the field;

[0049] Figure 5 It is a schematic diagram of the setting of the height scale and the level scale;

[0050] Figure 6 It is a schematic diagram of the arrangement of video cameras and corresponding scales on the front, side, and 45° direction of the vehicle. DETAILED DESCRIPTION

[0051] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0052] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0053] Embodiment 1

[0054] This embodiment provides a fire simulation test method for an electric bicycle, comprising the following steps:

[0055] Place the electric bicycle to be tested in the test field. Figure 1 As shown, at least one infrared thermal imager, at least one video camera and at least one heat flow meter are set up in the test field. The video camera uses its own local storage card to store data, and the infrared thermal imager transmits data through wires and stores it locally.

[0056] In this embodiment, a flat or rod-shaped heating device is used to heat a single cell in the battery of an electric bicycle. The surface of the heating device should be covered with ceramic, metal or insulating layer. For a block-shaped heating device with the same size as a single cell, the heating device can be used to replace one of the single cells and directly contact the surface of the triggered single cell; for a thin film heating device, it should always be attached to the surface of the triggering object, and the heating area of ​​the heating device should not be larger than the surface area of ​​the single cell; the heating surface of the heating device is directly in contact with the surface of the single cell, and the position of the heating device is as follows: Figure 2 shown.

[0057] like Figure 5 As shown, with the video camera placed in the direction directly in front of the vehicle, a height ruler and a horizontal ruler are arranged directly behind the vehicle. The length of the horizontal ruler is a, and the length of the height ruler is b. The horizontal ruler is fixed on the vertical ruler, and the vertical ruler is fixed on the ground and is on the same level as the vehicle.

[0058] During the test, turn on the vehicle power supply, so that the whole vehicle is in the power-on state, and heat a single battery in the vehicle battery at the maximum power of the heating device. Figure 2When the temperature of the triggered single cell differs from the temperature alarm threshold of the battery BMS by a set temperature value, such as when the temperature of the triggered single cell reaches 5°C before the temperature alarm threshold of the battery BMS, the heating power is reduced or the heating is stopped until the temperature gradually rises to the temperature alarm threshold, and the BMS alarm information and the on-board alarm hardware and function response are recorded.

[0059] Then, the triggered single cell battery is continuously heated at the maximum power until the triggered single cell battery undergoes thermal runaway, at which time the heating is stopped and the time and battery temperature at this time are recorded.

[0060] The judgment conditions for battery thermal runaway are as follows:

[0061] a) The triggered single cell produces a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0062] b) The temperature of the triggered single battery reaches the maximum operating temperature specified by the manufacturer;

[0063] c) The rate dT / dt of the triggered single cell is ≥1℃ / s and lasts for more than 3s.

[0064] When a) and c) or b) and c) occur, it is determined that the triggered single battery cell has thermal runaway.

[0065] During the entire test process, the voltage, temperature value, temperature rise rate, video information of the triggered single battery, and smoke information in the battery compartment are collected in real time.

[0066] The vehicle image information of the fire process is collected from multiple directions by video cameras. Based on the existing smoke recognition algorithm and flame recognition algorithm, combined with the smoke information collected by the smoke sensor, the time when the smoke and open flame appear is obtained. At the same time, the time difference between the appearance of smoke and thermal runaway, as well as the time difference between the appearance of flame and thermal runaway, is calculated.

[0067] Through the existing flame image recognition algorithm, the flame is identified in the image information collected by the video camera, and the height and width of the flame are calculated.

[0068] The calculation steps for the height and width of the flame are:

[0069] Calculate the number of horizontal ruler pixels n1 and height ruler pixels n2 in the image captured by the video camera, as well as the number of flame width pixels n3 and flame height pixels n4 in the corresponding image, and calculate the flame width and height by the following formula:

[0070] Flame width L = a × n3

[0071] n1

[0072] Flame height H = b × n4,

[0073] n2

[0074] Among them, a is the length of the horizontal scale and b is the length of the height scale.

[0075] The height and width of the flame are collected by video cameras, and the changes in the flame shape characteristics are identified in real time. The pictures with the largest flame width and highest height within each set time period after the flame appears are stored. In order to record the flame size characteristics at different angles at different time periods after the fire, video cameras and corresponding scales can be arranged on the front, side, and 45° direction of the vehicle, such as Figure 6 shown.

[0076] This embodiment also analyzes the distribution of the maximum temperature of the fire, specifically:

[0077] A spatial coordinate system is established under the perspective of the video camera that collects video information, and a photo is taken before the test. Several temperature sensors are set up to collect temperature information of the vehicle and its surroundings in real time during the test. A thermal imager is set up to fuse the spatial coordinates of the thermal imaging into the spatial coordinate system of the video camera, and thermal imaging information of the test site is collected in real time during the test.

[0078] During the test, the data of each temperature sensor, the temperature field and radiation heat flow of the vehicle and its surrounding area are recorded in real time.

[0079] The highest temperature value in the temperature data collected by the temperature sensor and the thermal imager in each fixed time interval after the start of the test is analyzed in real time, and its position is recorded.

[0080] If the highest temperature is collected by a temperature sensor, record the location of the temperature sensor. If the highest temperature is recorded by a thermal imager, mark the location through thermal imaging and record the coordinates of the marked location. Mark the location of each highest temperature and the corresponding time on the photo before the test.

[0081] After the test, a video of the highest temperature point location and dynamic changes in values ​​is generated on the photos taken before the test.

[0082] Embodiment 2

[0083] This embodiment provides an electric bicycle fire simulation test system, including a heating device for heating a vehicle battery, a battery temperature sensor arranged on a triggered battery cell, a voltage acquisition module for collecting the voltage of the triggered battery cell, a smoke sensor arranged in a vehicle battery compartment, a video camera arranged in a test field, a heat flux meter, and a processing module.

[0084] In this embodiment, a flat or rod-shaped heating device is used to heat a single cell in the battery of the electric bicycle. The surface of the heating device should be covered with ceramic, metal or insulating layer. For a block-shaped heating device with the same size as the single cell, the heating device can be used to replace one of the single cells and directly contact the surface of the triggered single cell; for a thin film heating device, it should always be attached to the surface of the triggering object, and the heating area of ​​the heating device should not be larger than the surface area of ​​the single cell; the heating surface of the heating device is directly in contact with the surface of the single cell, and the position of the heating device should be as follows: Figure 2 shown.

[0085] The battery temperature sensor, voltage acquisition module, smoke sensor, video camera, and heat flow meter are respectively connected to the processing module, and send the corresponding information they collect to the processing module, including but not limited to the battery temperature, the voltage information of the triggered single battery, whether smoke appears in the battery compartment, the image information and radiation heat flow information in the test field. The processing module is connected to the heating device control to control the opening and closing of the heating device.

[0086] The processing module performs an electric bicycle fire simulation test according to the electric bicycle fire simulation test method described in the first embodiment.

[0087] Embodiment 3

[0088] This embodiment provides an electric bicycle fire simulation test system, including a heating device for heating a vehicle battery, a battery temperature sensor arranged on a heated battery cell, a plurality of field temperature sensors arranged on a vehicle body and around the vehicle, a voltage acquisition module for collecting the voltage of the battery cell, a smoke sensor arranged in a vehicle battery compartment, a video camera, a thermal imager, a heat flow meter, and a processing module arranged in a test field;

[0089] In this embodiment, a flat or rod-shaped heating device is used to heat a single cell in the battery of the electric bicycle. The surface of the heating device should be covered with ceramic, metal or insulating layer. For a block-shaped heating device with the same size as the single cell, the heating device can be used to replace one of the single cells and directly contact the surface of the triggered single cell; for a thin film heating device, it should always be attached to the surface of the triggering object, and the heating area of ​​the heating device should not be larger than the surface area of ​​the single cell; the heating surface of the heating device is directly in contact with the surface of the single cell, and the position of the heating device should be as follows: Figure 2 shown.

[0090] like Figure 3 and Figure 4As shown, several temperature sensors are arranged on the left and right handlebars, saddle, storage box, and the heart and head positions of the vehicle when the person is driving the vehicle. Generally speaking, the position of the heart is 1.3m above the battery when the person is driving the vehicle, and the position of the head is 1.8m above the battery when the person is driving the vehicle.

[0091] The battery temperature sensor, the field temperature sensor, the voltage acquisition module, the smoke sensor, the video camera, the thermal imager, and the heat flow meter are respectively connected to the processing module, and send the corresponding information collected to the processing module, including but not limited to the battery temperature, the temperature of the left and right handlebars, the saddle, the storage box, the heart and the head when the person is driving the vehicle, the voltage information of the triggered single battery, whether there is smoke in the battery compartment, the image information, the thermal imaging information, and the radiation heat flow information in the test field. The processing module is connected to the heating device control to control the opening and closing of the heating device.

[0092] The processing module performs an electric bicycle fire simulation test according to the electric bicycle fire simulation test method described in Example 1.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0094] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A fire simulation test method for electric bicycles, It is characterized in that The following steps are involved: When the vehicle is powered on, the battery of the vehicle is heated and video information of the entire test process is collected; During the entire test process, the voltage, temperature value and temperature rise rate of the triggered single cells in the battery, as well as the smoke information in the battery compartment are continuously collected; When the battery experiences thermal runaway, stop heating and record the time and battery temperature. Identify the moment when smoke appears based on the video information and the smoke information in the battery compartment; identifying the moment when an open flame appears based on the video information; Calculate the time difference between the appearance of smoke and thermal runaway, and the time difference between the appearance of flame and thermal runaway.

2. The electric bicycle fire simulation test method according to claim 1, It is characterized in that When the following a and c, or b and c, occur, the battery is judged to have thermal runaway: a) The triggered single cell produces a voltage drop, and the drop value exceeds 25% of the initial voltage; b) The temperature of the triggered single battery reaches the maximum operating temperature specified by the manufacturer; c) The temperature change rate of the triggered single battery dT / dt ≥ 1°C / s and lasts for more than 3s.

3. The electric bicycle fire simulation test method according to claim 1, It is characterized in that When the temperature of the triggered single battery differs from the temperature alarm threshold of the battery BMS by a set temperature value, the heating power is reduced or heating is stopped until the temperature gradually rises to the temperature alarm threshold, and the BMS alarm information and the on-board alarm hardware and function response are recorded; The vehicle's battery is then heated until it experiences thermal runaway.

4. The electric bicycle fire simulation test method according to claim 1, It is characterized in that Establish a spatial coordinate system under the perspective of the video camera that collects video information, and take a pre-test photo; Set up several temperature sensors to collect temperature information of the vehicle and its surroundings in real time during the test; Set up a thermal imager, fuse the spatial coordinates of the thermal image into the spatial coordinate system of the video camera, and collect the thermal imaging information of the experimental field in real time during the test; Analyze in real time the highest temperature value in the temperature data collected by the temperature sensor and the thermal imager in each fixed time interval after the start of the test, and record its position; If the highest temperature is collected by a temperature sensor, record the location of the temperature sensor. If the highest temperature is recorded by a thermal imager, mark the location through thermal imaging and record the coordinates of the marked location. Mark the location of the highest temperature and the corresponding time on the photo before the test. After the test, the highest temperature point location and the dynamic change video of the value are automatically generated on the photo taken before the test.

5. The electric bicycle fire simulation test method according to claim 1, It is characterized in that A height ruler and a horizontal ruler are set in the test field, and the height and width of the flame are collected by the video camera, and the changes in the flame shape characteristics are identified in real time, and the pictures of the maximum flame width and the highest flame height within each set time period after the flame appears are stored.

6. The electric bicycle fire simulation test method according to claim 5, It is characterized in that The calculation steps for the height and width of the flame are: Calculate the number of horizontal ruler pixels n in the image captured by the video camera 1 and the number of pixels of the height scale n 2 , and the number of pixels n of the flame width in the corresponding image 3 The number of pixels with flame height n 4 , the flame width and height are calculated by the following formula: Flame width L = a × n 3 n 1 Flame height H = b × n 4 , n 2 Among them, a is the length of the horizontal scale and b is the length of the height scale.

7. An electric bicycle fire simulation test system, It is characterized in that It includes a heating device for heating a vehicle battery, a battery temperature sensor disposed on a triggered battery cell, a voltage acquisition module for collecting the voltage of the battery cell, a smoke sensor disposed in a vehicle battery compartment, a video camera disposed in a test field, and a processing module; The battery temperature sensor, voltage acquisition module, smoke sensor, and video camera are respectively connected to the processing module, and send the corresponding information collected to the processing module. The processing module is connected to the heating device control to control the opening and closing of the heating device; The processing module performs an electric bicycle fire simulation test according to the electric bicycle fire simulation test method according to claim 1, 2, 3, 5 or 6.

8. An electric bicycle fire simulation test system, It is characterized in that It includes a heating device for heating the vehicle battery, a battery temperature sensor arranged on the heated battery cell, a plurality of field temperature sensors arranged on the vehicle body and around the vehicle, a voltage acquisition module for collecting the voltage of the battery cell, a smoke sensor arranged in the vehicle battery compartment, a video camera and a thermal imager arranged in the test field, and a processing module; The battery temperature sensor, the field temperature sensor, the voltage acquisition module, the smoke sensor, the video camera, and the thermal imager are respectively connected to the processing module, and the corresponding information collected by them is sent to the processing module. The processing module is connected to the heating device control to control the opening and closing of the heating device; The processing module performs an electric bicycle fire simulation test according to the electric bicycle fire simulation test method according to claim 4.

9. The electric bicycle fire simulation test system according to claim 8, It is characterized in that The plurality of on-site temperature sensors are respectively arranged on the left and right handlebars of the vehicle, the saddle, the storage box, and the positions of the heart and the head when a person is driving the vehicle.

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