Method for determining thermal runaway parameters of energy storage equipment and energy storage system

Abstract

The invention discloses an energy storage equipment thermal runaway parameter determination method and an energy storage system. The method comprises the following steps: acquiring at least one first image of combustion flame emitted from the explosion venting port; determining the actual height of the flame according to the at least one first image; and according to the actual height, determining a first heat release rate when the energy storage equipment is on fire and combusted. According to the method, the actual height of the flame is obtained through the shot flame image, the first heat release rate of the energy storage equipment in the combustion process is further judged based on the flame height, and the influence of the energy storage equipment on the surrounding environment, equipment and personnel in the firing process can be rapidly evaluated in real time, so that a fire treatment strategy is made.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage devices, and in particular to a method for determining thermal runaway parameters of energy storage devices and an energy storage system. Background Art

[0002] Energy storage devices are common energy storage units in energy storage power stations. Due to limitations of space, cost and other factors, the layout of various energy storage devices in energy storage power stations is often relatively compact. However, once a storage device experiences thermal runaway and catches fire, the flames formed by the combustion reaction will pose a serious threat to the safety of adjacent energy storage devices. Therefore, the heat release rate can be used to evaluate the impact of a fire in an energy storage device on the surrounding environment, equipment and personnel.

[0003] At present, the heat release rate is mainly calculated by collecting all the flue gases produced by combustion. After the flue gases are fully mixed in the exhaust duct, the mass flow rate, composition, oxygen concentration, etc. are measured at the outlet. The mass of oxygen consumed in the combustion process is calculated, thereby obtaining the heat release rate in the combustion process.

[0004] However, the current method of obtaining heat release rate is very inefficient. Summary of the invention

[0005] In a first aspect, the present application provides a method for determining thermal runaway parameters of an energy storage device, wherein the thermal runaway parameters include a heat release rate, and an explosion vent is provided on the energy storage device, and the method includes: Acquire at least one first image of a burning flame emerging from the explosion vent; determining an actual height of the flame based on the at least one first image; A first heat release rate when the energy storage device catches fire is determined according to the actual height.

[0006] In the embodiment of the present application, since the flame of the energy storage device is concentrated at the explosion vent after it catches fire, the actual height of the flame can be obtained through the flame image captured by the camera, and the first heat release rate of the energy storage device during the combustion process can be further determined based on the flame height. The impact of the energy storage device on the surrounding environment, equipment and personnel during the fire process can be evaluated in real time and quickly, so as to formulate a fire handling strategy.

[0007] In a possible implementation of the first aspect, after determining, according to the actual height, a first heat release rate when the energy storage device is on fire, the method further includes: Obtaining the energy storage value, combustion efficiency and mass loss rate of the energy storage device when the energy storage device catches fire and burns; Determining the combustion heat value of the energy storage device according to the energy storage value; determining a second heat release rate of the energy storage device according to the combustion efficiency, the combustion heat value and the mass loss rate; A target heat release rate of the energy storage device is determined according to the first heat release rate and the second heat release rate.

[0008] In an embodiment of the present application, by calculating the mass loss rate of the energy storage device after fire and combustion, and based on the mass loss rate, the second heat release rate of the energy storage device can be further determined, and then according to the first heat release rate and the second heat release rate, the target heat release rate is obtained, so that the impact of the energy storage device on the surrounding environment, equipment and personnel during the fire process can be more accurately evaluated.

[0009] In a possible implementation manner of the first aspect, determining the actual height of the flame according to the at least one first image includes: determining a target image in the at least one first image; Performing binarization processing on the target image to obtain a binarized image of the target image; Determine a first height of a flame tip in the binary image and a second height of a flame root in the binary image according to pixel values ​​of pixels in the binary image; Obtaining a height difference between the first height and the second height; According to the height difference, the actual height of the flame burning at the explosion vent is determined.

[0010] In the embodiment of the present application, by binarizing the image, the flame tip and the flame root in the image can be accurately found, and after the height difference is calculated, the first heat release rate can be calculated more accurately, thereby improving the accuracy of the first heat release rate.

[0011] In a possible implementation manner of the first aspect, binarizing the target image to obtain a binarized image of the target image includes: Obtain the color value of each pixel in the target image under each color channel and the weight coefficient corresponding to each color channel; Determine the grayscale value of the pixel point according to the color value of the pixel point in each color channel and the weight coefficient; According to the gray value of each pixel, a binary image of the target image is obtained.

[0012] In the embodiment of the present application, by performing weighted summation on the color values ​​in each color channel to obtain a grayscale value, noise in the image can be eliminated, and the flame in the image after binarization processing can be more accurately identified.

[0013] In a possible implementation manner of the first aspect, determining, according to pixel values ​​of pixels in the binary image, a first height of the flame tip in the binary image and a second height of the flame root in the binary image, includes: Determining a flame outline in the binary image according to pixel values ​​of pixels in the binary image; Determining, according to the flame profile, a first direction of the flame tip toward the flame root and a second direction of the flame root toward the flame tip; Detecting pixel points in the binary image row by row along the first direction to determine a first target row in the binary image, wherein there are target pixel points in the first target row whose pixel values ​​match a preset pixel value range; Detecting pixel points in the binary image row by row along the second direction to determine a second target row in the binary image, wherein there are target pixel points in the second target row whose pixel values ​​match a preset pixel value range; Determining the first height according to the height of the first target row in the binary image; The second height is determined according to the height of the second target row in the binary image.

[0014] In the embodiment of the present application, by checking the binary image line by line along the first direction or the second direction, the positions of the flame root and the flame tip in the binary image can be found more quickly, thereby improving the image processing rate.

[0015] In a possible implementation manner of the first aspect, the number of the target images is at least two; and determining the first height according to a height of the first target row in the binary image includes: Obtaining the height of the first target row in the binary image of each target image; Determine an average height according to the height of the first target row in each binary image; The first height is determined according to the average height.

[0016] In the embodiment of the present application, by obtaining the average height, the error caused by the jumping of the tip during the flame combustion process can be avoided, so that the height difference between the flame tip and the flame root can be calculated more accurately.

[0017] In a possible implementation manner of the first aspect, the target image includes a reference object, and determining the actual height of the flame burning at the explosion vent according to the height difference includes: Obtaining the image size of the reference object in the binary image; Determining a scaling ratio according to the image size and the actual height of the reference object; According to the scaling ratio and the height difference, an actual height of the flame burning at the explosion vent is determined.

[0018] In the embodiment of the present application, by setting a reference object, the actual height of the flame burning at the explosion outlet can be determined more quickly and accurately, thereby improving the calculation efficiency of the first heat release rate.

[0019] In a possible implementation manner of the first aspect, determining the target image in the at least one first image includes: N target images within a preset time period are selected from the at least one first image, and the preset time period is greater than or equal to a beating period of a flame tip burning at the explosion vent.

[0020] In this embodiment, by acquiring multiple flame images in at least one beating cycle, multiple target images are obtained as samples to calculate the average height, which can reduce errors in the average height calculation process and improve calculation accuracy.

[0021] In a possible implementation of the first aspect, determining, according to the actual height, a first heat release rate when the energy storage device is on fire and burning includes: Determine the equivalent diameter of the flame root emerging from the explosion vent according to the equivalent area of ​​the explosion vent; The first heat release rate is determined according to the actual height of the flame and the equivalent diameter.

[0022] In the embodiment of the present application, by using the equivalent area of ​​the explosion vent to determine the equivalent diameter of the flame root, the heat release rate of the energy storage device during the combustion process can be monitored simply and quickly.

[0023] In a second aspect, the present application provides an energy storage system, comprising an energy storage device, a processor and a camera device, wherein the processor is connected to the camera device, and the energy storage device is provided with an explosion vent; the camera device is used to capture at least one first image of a burning flame emerging from the explosion vent; and the processor is used to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0025] Figure 1 A schematic diagram of an image acquisition scenario provided in an embodiment of the present application; Figure 2 A schematic diagram of a flow chart of a method for determining thermal runaway parameters of an energy storage device provided in an embodiment of the present application; Figure 3 A flow chart of a method for determining a heat release rate provided in an embodiment of the present application; Figure 4 A schematic diagram of the change of the mass of the energy storage device over time provided in an embodiment of the present application; Figure 5 A schematic diagram of the change of mass loss rate over time provided in an embodiment of the present application; Figure 6 A schematic diagram of a flame height determination process provided in an embodiment of the present application; Figure 7 A schematic diagram of binarization processing provided in an embodiment of the present application; Figure 8 A schematic diagram of a binarization process provided in an embodiment of the present application; Fig. 9 A schematic diagram of a height determination process provided in an embodiment of the present application; Fig.10 A schematic diagram of a height determination method flow chart provided in an embodiment of the present application; Fig.11 A schematic diagram of a process for determining the actual height of a flame provided in an embodiment of the present application; Fig.12 A schematic diagram of the structure of a device for determining thermal runaway parameters of an energy storage device provided in an embodiment of the present application; Fig.13 A schematic diagram of the structure of the energy storage system provided in the embodiment of the present application; Fig.14 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present application.

[0026] In the drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] Energy storage equipment may refer to a device formed by stacking multiple batteries. In order to prevent the batteries from being directly exposed to the external environment, the energy storage equipment usually has a shell, and the battery cells are wrapped inside the shell. The internal battery cells are the main fire load. Exemplarily, the energy storage equipment may refer to a device composed of multiple battery cells stacked in a container. In this case, the external container is the shell of the energy storage equipment.

[0029] Energy storage equipment is a common energy storage unit in energy storage power stations. Taking container-shaped energy storage equipment as an example, due to limitations of site, cost and other factors, the layout of these containers in energy storage power stations is often relatively compact. However, once a container has thermal runaway and catches fire, the flame formed by the combustion reaction will pose a serious threat to the safety of adjacent containers. When evaluating the impact of container fires on the surrounding environment, equipment and personnel, the heat release rate after the container has thermal runaway combustion is one of the most critical parameters. In related technologies, the methods for measuring the heat release rate in fires include combustion smoke analysis and micro calorimeters, cone calorimeters, accelerating calorimeters, etc. Among them, the combustion smoke analysis method collects all the smoke generated by the combustion in the experiment. After being fully mixed in the exhaust pipe, its mass flow rate, components, oxygen concentration, etc. are measured at the outlet position. The mass of oxygen consumed during the combustion process is calculated, thereby obtaining the heat release rate during the material combustion process. However, this process is relatively complicated and consumables are large. However, the range of various types of calorimeters is limited and cannot be used to measure large-scale fires. Moreover, the calorimetric equipment is threatened by high temperature. In summary, for energy storage devices formed by multiple battery stacks (such as energy storage devices in the form of containers), this type of fire source has high energy density and large fire load. The heat release rate after a thermal runaway fire can reach tens of megawatts. Currently, there is no suitable and efficient heat release rate measurement method for fire sources of this magnitude.

[0030] In response to the above problems, the present application provides a solution for determining the thermal runaway parameters of energy storage equipment. Among them, the thermal runaway parameters of energy storage equipment mainly refer to the above-mentioned heat release rate. This solution uses a camera to collect images of the energy storage equipment when it is on fire, uses image analysis to determine the actual height of the flame, and combines the inherent parameters to determine the heat release rate, thereby solving the problem of calculating the heat release rate of a fire after thermal runaway of the energy storage equipment, and providing key inputs for the risk and hazard assessment of heat spread in energy storage containers, thereby improving the safety of fires in energy storage power stations.

[0031] For example, Figure 1 A schematic diagram of an image acquisition scenario provided in an embodiment of the present application, such as Figure 1 As shown, after the energy storage device 10 thermally runs away and catches fire, there is a risk of combustion and explosion. Therefore, in order to reduce the damage to the structure of the energy storage device after an accidental explosion and the thermal feedback effect on other nearby energy storage devices, an explosion venting plate is usually set on the top of the energy storage device. For a fire caused by thermal runaway of an energy storage device, this fire scene is a typical confined space fire. Due to insufficient oxygen supply, its external flames are mainly concentrated in the pores. When the internal pressure of the energy storage device reaches the explosion venting pressure, the explosion venting plate will be opened. At this time, the thermal runaway gas will escape and burn outward through the explosion venting port that appears after the explosion venting plate is opened.

[0032] Among them, it can be considered that the subsequent combustion at the explosion vent is buoyancy diffusion combustion. Setting an explosion vent plate on the top of the energy storage device can effectively ensure the integrity of the energy storage device structure, realize directional combustion at the top of the fire source, and reduce the risk of heat spread. In this fire scenario, when no explosion occurs, the initial momentum of the combustible gas that diffuses from the top explosion vent to the outside of the container is very small, and is mainly controlled by buoyancy. It freely diffuses and burns at the explosion vent to form a turbulent diffusion flame.

[0033] based on Figure 1 In the scenario shown, one or more camera devices (such as camera 11) can be arranged around the burning energy storage device. By taking flame images with cameras at different positions, the changes in flame shape can be recorded more completely.

[0034] The technical solution of the present application is described in detail below through specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0035] Figure 2 This is a flow chart of a method for determining thermal runaway parameters of an energy storage device provided in an embodiment of the present application. This method can be applied to an electronic device with a processor, with the processor of the electronic device as the execution subject. Figure 2 As shown, the method may include the following steps: Step S210: Acquire at least one first image of a burning flame emerging from the explosion vent.

[0036] In this embodiment, continue to refer to the above Figure 1 One or more cameras may be arranged around the energy storage device that is on fire, and at least one first image may be obtained by shooting with cameras at different positions, thereby being able to fully record the morphological changes of the flame during the combustion process.

[0037] In this embodiment, a high-resolution camera device, such as a visible light camera, can be used to collect images of the flame during the combustion process, and image preprocessing techniques (such as denoising and edge detection techniques, etc.) can be used to remove interference, improve image quality, and extract the boundary and color information of the flame. The boundary and color information of the flame can be used to subsequently determine the actual height of the flame.

[0038] In this embodiment, for a container with an explosion vent, the flame will burn near the explosion vent, which is the root of the fire source. In order to capture the complete flame, the camera device usually needs to be spaced a certain distance from the energy storage device. The horizontal spacing between the camera and the container can be adjusted according to the actual situation, as long as the flame image can be captured completely.

[0039] In addition, it may not be possible to accurately capture the three-dimensional shape of the flame using only one camera, so cameras can be arranged at different locations. For example, in order to capture and record the true shape of the flame and obtain a more accurate flame height, two cameras can be used, one camera is placed directly in front of or behind the energy storage device, and the other camera is placed directly to the left or right of the energy storage device.

[0040] Step S220: determining the actual height of the flame according to at least one first image.

[0041] In this embodiment, the flame image can be extracted from the first image by using an image processing algorithm, and the image height of the flame in the first image can be determined by identifying the flame tip and the flame root in the flame image.

[0042] Furthermore, the actual height of the flame burning at the explosion vent can be further inferred through a neural network model or by utilizing camera parameters in combination with the image height of the flame.

[0043] For example, taking the camera parameters including the focal length of the camera and the horizontal straight-line distance between the camera and the energy storage device as an example, the height of a target point in the first image is obtained, and then the actual height of the target point can be determined based on the height of the pixel point in the first image, the focal length of the camera and the horizontal straight-line distance between the camera and the energy storage device through geometric principles. Based on this, the actual height of the flame root and the actual height of the flame tip can be obtained, thereby determining how high the flame is.

[0044] Step S230: Determine a first heat release rate when the energy storage device is on fire according to the actual height.

[0045] In this embodiment, there is a correlation between the heat release rate of the fire source, the flame height, and the characteristic diameter of the fire source. Therefore, a relationship between the heat release rate of the fire source, the flame height, and the characteristic diameter of the fire source can be constructed, and the first heat release rate of the energy storage device when it is on fire can be determined by the relationship.

[0046] In addition, in some embodiments, the heat release rate can also be determined based on the flame shape in the image. Specifically, it can be divided into two methods: machine learning and empirical model. For the machine learning method, the machine learning model can predict the heat release rate of the output fire source in real time based on the input image.

[0047] Among them, the machine learning model needs to be pre-trained with previous thermal runaway fire accident data of energy storage equipment as model samples.

[0048] In the embodiment of the present application, since the flame of the energy storage device is concentrated at the explosion vent after it catches fire, the actual height of the flame can be obtained through the flame image captured by the camera, and the first heat release rate of the energy storage device during the combustion process can be further determined based on the flame height. The impact of the energy storage device on the surrounding environment, equipment and personnel during the fire process can be evaluated in real time and quickly, so as to formulate a fire handling strategy.

[0049] Furthermore, Figure 3 A flow chart of a method for determining a heat release rate provided in an embodiment of the present application, such as Figure 3 As shown, it includes the following steps: Step S310: Obtain the energy storage value, combustion efficiency and mass loss rate of the energy storage device when the energy storage device catches fire.

[0050] In this embodiment, continuing to take the energy storage device in the form of a container as an example, a high-precision weighing device can be used to monitor the overall mass change of the container during the thermal runaway fire and combustion process in real time, thereby determining the mass loss rate.

[0051] For example, the container can be placed on a high-precision weighing scale or other weighing platform to monitor the weight change of the container in real time. Since the flame during the burning process of the container has a strong thermal feedback to the weighing scale, the weighing scale needs to be insulated to a certain extent and installed firmly, and the weighing scale needs to be calibrated in advance. For example, a heat insulation layer can be set between the weighing scale and the container.

[0052] In this embodiment, taking the processor mentioned above as an example of the execution subject, a weighing device (such as a floor scale) needs to be connected to the processor to collect and transmit the mass of the container to the processor in real time to obtain the change of the mass of the container over time when it is on fire.

[0053] For example, Figure 4 A schematic diagram of the change of the mass of the energy storage device over time provided in the embodiment of the present application, such as Figure 4 As shown, the mass of the energy storage device decreases continuously during the combustion process.

[0054] The weighing device can be set to collect the mass of the energy storage device every preset sampling period (for example, 1 second). The difference between the mass at any moment and the mass at the previous moment can be regarded as the average mass loss rate at the previous moment. .

[0055] In this embodiment, the average mass loss rate at the previous moment can be output synchronously while the processor collects the mass change data. . And show the mass loss rate-time curve. Exemplary, Figure 5The schematic diagram of the change of mass loss rate over time provided in the embodiment of the present application is as follows: Figure 5 As shown, the mass loss rate of the energy storage device gradually decreases during the combustion process.

[0056] In this embodiment, the peak value of the battery heat release rate increases with the increase of the energy storage value of the battery. For the energy storage device, the energy storage value of each battery therein can be considered to be slightly different, so it can be unified into a specific value. Among them, the energy storage value can be determined according to the remaining power (State Of Charge, SOC).

[0057] In this embodiment, the combustion efficiency is related to the type of combustibles and the combustion state. For battery thermal runaway fire, the combustibles are mainly gaseous combustibles such as hydrogen, and the combustion efficiency is relatively high. For example, the combustion efficiency interval can be set to [0.3, 0.9], and the specific value of the combustion efficiency can be determined based on actual conditions. Among them, for the purpose of safety assessment, the combustion efficiency can take a conservative value of 0.9.

[0058] Step S320: Determine the combustion calorific value of the energy storage device according to the energy storage value.

[0059] In this embodiment, the combustion heat value of the energy storage device at the energy storage value can be measured by a calorimeter. .

[0060] In addition, for thermal runaway combustion of energy storage equipment, the internal battery cells are the main fire load, and the fire load of other combustibles is relatively small and can be ignored. The combustion calorific value of the battery cell can be obtained through the battery cell thermal runaway calorimetry experiment.

[0061] Step S330: Determine a second heat release rate of the energy storage device according to the combustion efficiency, the combustion calorific value and the mass loss rate.

[0062] In this embodiment, the second heat release rate can be calculated using the following formula:

[0063] in, is the second heat release rate; For combustion efficiency; is the mass loss rate of the energy storage device; It is the combustion calorific value of the energy storage equipment.

[0064] Step S340: determining a target heat release rate of the energy storage device according to the first heat release rate and the second heat release rate.

[0065] In this embodiment, the first heat release rate and the second heat release rate may be weighted and summed to obtain the target heat release rate. Alternatively, the middle value of the first heat release rate and the second heat release rate may be taken as the target heat release rate.

[0066] In addition, in some embodiments, the target heat release rate may be a range, wherein, according to the magnitude relationship between the first heat release rate and the second heat release rate, the upper limit of the range may be the first heat release rate, and the lower limit of the range may be the second heat release rate.

[0067] In the embodiments of the present application, the external environment of the energy storage device may change, which will change the shape of the flame and make it impossible to correctly predict the heat release rate of the fire source. For this reason, a high-precision weighing device is introduced to monitor the mass change of the energy storage device, and the second heat release rate is calculated as a supplement, which avoids the irrationality of calculating the heat release rate of the energy storage device through images. The target heat release rate is obtained based on the first heat release rate and the second heat release rate, which can more accurately evaluate the impact of the energy storage device on the surrounding environment, equipment and personnel during the fire process.

[0068] Figure 6 The flame height determination process diagram provided in the embodiment of the present application is as follows: Figure 6 As shown, the method may specifically include the following steps: Step S610: determining a target image in at least one first image.

[0069] In this embodiment, the target image may be one or more images. As mentioned above, flames at different angles may be photographed by multiple cameras to generate at least one first image. Based on this, one or more images with the best photographing effect may be selected from the first images taken as the target image. This may improve the accuracy of subsequent flame height.

[0070] Step S620: binarize the target image to obtain a binarized image of the target image.

[0071] In this embodiment, the flame area and the background area in the visible light image can be separated by grayscale threshold segmentation method, so as to extract the flame image. Specifically, the grayscale value range of the grayscale threshold segmentation method is 0-255, indicating that the brightness is from dark to light, and the color in the corresponding image is from black to white.

[0072] Among them, since the gray value of the flame area is higher than the gray value of the background area, the gray value above the threshold is set as the flame area, represented by white, and the gray value below the threshold is set as the non-flame area, represented by black, that is, a black and white binary image is obtained. Among them, the white area in the binary image is the area occupied by the flame image, and the black area is the area occupied by the background image.

[0073]

[0074] In the above formula (1), Represents the pixel value of the pixel at the xth row and yth column in the i-th target image, is the set threshold.

[0075] Step S630: determining a first height of the flame tip in the binary image and a second height of the flame root in the binary image according to the pixel values ​​of the pixels in the binary image.

[0076] Step S640: Obtaining the height difference between the first height and the second height.

[0077] In this embodiment, the distance from the flame tip to the flame root in the binary image is the height difference between the first height and the second height.

[0078] For example, Figure 7 A schematic diagram of binarization processing provided in the embodiment of the present application is shown in FIG. Figure 7 As shown, by performing binarization processing, the target image is converted into a binary image, and the white area in the binary image is the area occupied by the flame image.

[0079] Step S650: Determine the actual height of the flame burning at the explosion vent according to the height difference.

[0080] In this embodiment, the camera parameters (including the focal length of the camera, the distance between the camera and the energy storage device, etc.) for shooting the target image can be obtained, and then the actual height can be further determined based on the camera parameters and the height difference. Exemplarily, the first height / camera focal length=actual height of the flame tip / distance between the camera and the energy storage device. The second height / camera focal length=actual height of the flame root / distance between the camera and the energy storage device.

[0081] In the embodiment of the present application, by binarizing the image, the flame tip and the flame root in the image can be accurately found, and the height difference can be calculated, thereby achieving the effect of automatically measuring the flame height through image processing technology, reducing the error and cost investment of manual measurement. In addition, the measurement can be performed within a safe distance, which is suitable for high temperature and dangerous environments, and improves the safety of measuring the actual flame height.

[0082] Further, based on the above embodiments, in other embodiments, Figure 8 A schematic diagram of the binarization process provided in the embodiment of the present application is shown in FIG. Figure 8 As shown, it includes the following steps: Step S810: Obtain the color value of each pixel in the target image in each color channel and the weight coefficient corresponding to each color channel.

[0083] Step S820: Determine the grayscale value of the pixel point according to the color value and weight coefficient of the pixel point in each color channel.

[0084] Step S830: Obtain a binary image of the target image according to the gray value of each pixel.

[0085] In this embodiment, the target image captured by the camera is taken as an RGB image, which includes three color channels, namely, a red (R) color channel, a green (G) color channel, and a blue (B) color channel. Each color channel has a corresponding color channel value.

[0086] For example, the grayscale value of each pixel of the target image can be calculated by the following formula:

[0087] In the above formula (2), is the gray value, is the color value corresponding to the red color channel, G is the color value corresponding to the green color channel, and B is the color value corresponding to the blue color channel. k1, k2 and k3 are the corresponding weight coefficients. For example, k1 is , k2 is , k3 takes the value .

[0088] In the embodiment of the present application, by flexibly configuring the weight coefficient of each color channel, it is possible to adapt to the sensitivity of different human eyes to different colors, thereby being able to adapt to different groups of people and improving applicability.

[0089] The following describes in detail how to determine the heights of the flame tip and the flame root in the binary image through some embodiments.

[0090] Fig. 9 A schematic diagram of a height determination process provided in an embodiment of the present application is shown in FIG. Fig. 9 As shown, it includes the following steps: Step S910: determining the flame outline in the binary image according to the pixel values ​​of the pixels in the binary image.

[0091] In this embodiment, the pixels representing the flame are different from the pixels representing other objects such as the background. Figure 7 , the pixels representing the flame are white pixels, while the pixels representing other objects such as the background are black pixels. Based on this, if the pixel value difference between two adjacent pixels is large, then this can be regarded as part of the flame outline.

[0092] Step S920: determining a first direction from the flame tip toward the flame root and a second direction from the flame root toward the flame tip according to the flame profile.

[0093] In this embodiment, it can be understood that the shape of the flame tip is different from the shape of the flame root. Among them, the first position where the center point of the flame tip is located, the second position where the center point of the flame root is located, the direction from the first position to the second position is taken as the first direction, and the opposite direction of the first direction is taken as the second direction.

[0094] In addition, in some embodiments, the shooting angle of the camera mentioned above when photographing the flame burning at the explosion vent may also be obtained; and then the first direction and the second direction are determined according to the shooting angle.

[0095] For example, assuming that the camera is photographing a burning flame vertically, in the generated first image, the tip of the flame is at the top of the first image, and the root of the flame is at the bottom of the first image, so the first direction may refer to from the top of the first image to the bottom of the first image, and the second direction may refer to from the bottom of the first image to the top of the first image.

[0096] Step S930: Detecting pixel points in the binary image row by row along a first direction to determine a first target row in the binary image, where there are target pixel points whose pixel values ​​match a preset pixel value range.

[0097] Step S940: Detecting the pixel points in the binary image row by row along the second direction to determine a second target row in the binary image, where there are target pixel points whose pixel values ​​match the preset pixel value range.

[0098] In this embodiment, after the binary image is obtained by binarization processing, the binary image is scanned line by line in the first direction (for example, from top to bottom) to find the first line containing flames (refer to Figure 7 , i.e. white pixels) , as the first target row, which represents the position of the flame tip. After determining the row number where the flame tip is located, rescan the binary image row by row in the second direction (e.g., scanning from bottom to top) to find the first row containing the flame (reference Figure 7 , that is, white pixels) , this line represents the root position of the flame.

[0099] Step S950: Determine the first height according to the height of the first target line in the binary image. Step S960: Determine the second height according to the height of the second target line in the binary image.

[0100] In this embodiment, the height of the first target line in the binary image represents the first height of the flame tip, and the height of the second target line in the binary image represents the second height of the flame root.

[0101] In the embodiment of the present application, the outline of the flame is automatically identified through image processing technology, and the actual height of the flame is accurately measured. The actual height of the flame can be measured automatically and non-contactly, which is suitable for occasions where the flame height needs to be accurately monitored, such as fire safety monitoring, combustion efficiency analysis, etc., to improve the applicability of the scene.

[0102] It is mentioned above that the number of target images can be multiple. In other embodiments, when there are multiple target images, Fig.10 A flow chart of a method for determining height provided in an embodiment of the present application is shown in FIG. Fig.10 As shown, it may include the following steps: Step S1010: Obtain the height of the first target row in the binary image of each target image.

[0103] Step S1020: determining an average height according to the height of the first target row in each binary image.

[0104] Step S1030: Determine a first height according to the average height.

[0105] In this embodiment, through the description of the above embodiment, a first target row can be obtained from the binary image corresponding to each target image. Each first target row has a corresponding height in its binary image. At this time, the heights corresponding to all first target rows can be averaged as the first height.

[0106] Since the flame tip is constantly jumping during the flame combustion process, the actual height of the flame tip may be different in each first image. Therefore, it is necessary to obtain the actual average height of the flame tip to reduce the error.

[0107] Specifically, the time for collecting the first image needs to be extended to at least one flame jump cycle. In some embodiments, N target images within a preset time period can be selected from at least one first image, and the preset time period is greater than or equal to the jump cycle of the flame tip burning at the explosion vent.

[0108] For example, 50 milliseconds can be taken as a preset time period, and n frames of first images within 50 milliseconds can be extracted as target images, and the first target row where the flame tip is located in the n frames of target images can be calculated.

[0109] In this embodiment, the first height and the second height may be the number of rows, for example, the average value of the number of rows where the first target row is located in the binary image is used as the first height.

[0110] When there are multiple target images, the number of rows in the first target row in each target image is averaged, and then subtracted from the number of rows in the second target row where the flame root is located, which is the height difference mentioned above, that is, the number of rows occupied by the flame in the binary image. .

[0111] In this embodiment, by obtaining the number of the first target row in the binary image corresponding to each target image and calculating the average value as the first height of the flame tip, the measurement error caused by the tip jumping during the flame combustion process can be reduced, and the accuracy of the calculation of the actual flame height can be improved. In addition, by obtaining the jumping period of the flame tip and selecting the target image from the first image within a preset time period greater than the flame tip jumping period, the first image is also screened.

[0112] Furthermore, by shooting flame images with cameras at different positions, the changes in flame morphology can be recorded more completely, but if there is no reference object, the actual height of the flame cannot be quickly calculated. Therefore, a reference object of known height (such as a 1-meter-high pole) can be placed around the explosion vent. In this way, when the camera shoots the flame burning at the explosion vent, the reference object will also be captured in the first image. In this way, in some embodiments, the first image containing the reference object image can be selected as the target image.

[0113] in, Fig.11 The actual flame height determination process diagram provided in the embodiment of the present application is as follows: Fig.11 As shown, it includes the following steps: Step S1110: Obtain the image size of the reference object in the binary image.

[0114] Step S1120: Determine the scaling ratio according to the image size and the actual height of the reference object.

[0115] Step S1130: Determine the actual height of the flame burning at the explosion vent according to the scaling ratio and the height difference.

[0116] In this embodiment, the reference object can be a The long rod can be erected vertically around the explosion vent, so that the scaling ratio can be determined by the length L of the long rod and the length of the long rod in the binary image.

[0117] The pixels occupied by the benchmark in the target image are calculated to obtain the corresponding scaling ratio, which can be expressed in meters / pixel, that is, the actual length represented by each pixel.

[0118] Specifically, the number of rows that the flame occupies in the binary image is mentioned above , and the product of the actual length L corresponding to the unit pixel is the actual height of the flame .

[0119]

[0120] In the above formula (3), is the actual height of the flame, and n is the number of target images.

[0121] In this embodiment, the reference object may also be a calibration plate with a width of W, which may be placed horizontally around the explosion vent, so that the scaling ratio may also be determined by the width W of the calibration plate and the width of the calibration plate in the binary image. That is, the image size may refer to the width or length, etc.

[0122] In the embodiment of the present application, by setting a reference object at the explosion vent, the actual height of the burning flame can be determined more conveniently and quickly through the image size of the reference object and the accuracy can be guaranteed.

[0123] In real life, the heat release rate is related to the flame shape. Specifically, the heat release rate is related to the flame height and the characteristic diameter of the fire source. Therefore, in some embodiments, the first heat release rate can be determined by the following steps.

[0124] Step a: Determine the equivalent diameter of the root of the flame emerging from the explosion vent according to the equivalent area of ​​the explosion vent; Step b: Determine the first heat release rate according to the actual height and equivalent diameter of the flame.

[0125] In this embodiment, the first heat release rate can be calculated by the following empirical model:

[0126] In the above formula (4), is the actual height of the flame, is the first heat release rate, is the characteristic diameter of the fire source, k4 and k5 are constants.

[0127] The characteristic diameter of the fire source can refer to the equivalent diameter of the flame root, which can be measured by the equivalent area of ​​the top explosion vent. Find:

[0128] Further, assuming that k4 is , k5 is , substituting formula (5) into formula (4) can calculate the first heat release rate:

[0129] In an embodiment of the present application, an image of the flame is captured by a camera, and the flame image is extracted and calculated using computer image processing technology to obtain the actual height of the flame. The first heat release rate can be obtained through an empirical model, and the heat release rate of the energy storage container can be monitored quickly and accurately, avoiding the limitations of traditional measurement methods. It is suitable for heat monitoring in areas where direct contact with equipment or in high-risk environments.

[0130] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the method of the present application.

[0131] Fig.12 A schematic diagram of the structure of a device for determining thermal runaway parameters of an energy storage device provided in an embodiment of the present application, such as Fig.12 As shown, the thermal runaway parameter determination device 1200 may specifically include an acquisition module 1210 , a height determination module 1220 and a rate calculation module 1230 .

[0132] The acquisition module 1210 is used to acquire at least one first image of the burning flame emerging from the explosion vent. The height determination module 1220 is used to determine the actual height of the flame based on the at least one first image. The rate calculation module 1230 is used to determine the first heat release rate when the energy storage device is on fire and burning based on the actual height.

[0133] Optionally, it also includes a target rate determination module, which is used to: obtain the energy storage value, combustion efficiency and mass loss rate of the energy storage device when the energy storage device ignites and burns; determine the combustion calorific value of the energy storage device based on the energy storage value; determine the second heat release rate of the energy storage device based on the combustion efficiency, combustion calorific value and mass loss rate; determine the target heat release rate of the energy storage device based on the first heat release rate and the second heat release rate.

[0134] Optionally, the height determination module can be specifically used to: determine a target image in at least one first image; binarize the target image to obtain a binarized image of the target image; determine a first height of the flame tip in the binarized image and a second height of the flame root in the binarized image based on pixel values ​​of pixels in the binarized image; obtain a height difference between the first height and the second height; and determine an actual height of the flame burning at the explosion vent based on the height difference.

[0135] Optionally, the height determination module can be specifically used to: obtain the color value of each pixel in the target image under each color channel and the weight coefficient corresponding to each color channel; determine the grayscale value of the pixel according to the color value and weight coefficient of the pixel in each color channel; obtain a binary image of the target image according to the grayscale value of each pixel.

[0136] Optionally, the height determination module can be specifically used to: determine the flame outline in the binary image according to the pixel values ​​of the pixel points in the binary image; determine the first direction from the flame tip toward the flame root and the second direction from the flame root toward the flame tip according to the flame outline; detect the pixel points in the binary image row by row along the first direction to determine the first target row in the binary image, in which there are target pixel points whose pixel values ​​match the preset pixel value range; detect the pixel points in the binary image row by row along the second direction to determine the second target row in the binary image, in which there are target pixel points whose pixel values ​​match the preset pixel value range; determine the first height according to the height of the first target row in the binary image; determine the second height according to the height of the second target row in the binary image.

[0137] Optionally, the number of target images is at least two; the height determination module can be specifically used to: obtain the height of the first target row in the binary image of each target image; determine the average height based on the height of the first target row in each binary image; determine the first height based on the average height.

[0138] Optionally, the target image includes a reference object; the height determination module can be specifically used to: obtain the image size of the reference object in the binary image; determine the scaling ratio according to the image size and the actual height of the reference object; determine the actual height of the flame burning at the explosion vent according to the scaling ratio and the height difference.

[0139] Optionally, the height determination module may be specifically configured to: select N target images within a preset time period from at least one first image, where the preset time period is greater than or equal to a beating period of a flame tip burning at the explosion vent.

[0140] Optionally, the rate calculation module may be specifically used to: determine an equivalent diameter of a flame root emerging from the explosion vent according to an equivalent area of ​​the explosion vent; and determine a first heat release rate according to an actual height and equivalent diameter of the flame.

[0141] The device provided in the embodiment of the present application can be used to execute the method in the above embodiment. Its implementation principle and technical effect are similar and will not be repeated here.

[0142] An embodiment of the present application also provides an energy storage system, which includes an energy storage device, a processor, and a camera device. The processor is connected to the camera device, and the energy storage device is provided with an explosion vent.

[0143] The camera device is used to capture at least one first image of the burning flame emerging from the explosion vent, and the processor executes the algorithm according to the at least one first image and the pre-configured algorithm and parameters to output a first heat release rate.

[0144] Exemplarily, the imaging device may include multiple, for example, multiple cameras, and the multiple imaging devices are arranged at different positions of the energy storage device.

[0145] For example, the first camera may be disposed directly in front of or behind the energy storage device, and the second camera may be disposed directly on the left side or on the right side of the energy storage device.

[0146] For example, since the flames burn concentratedly near the explosion vent, which is the root of the fire source, in order to be able to clearly capture the root of the flame, the camera can be arranged at the same height as the explosion vent, that is, the camera is at the same height as the explosion vent.

[0147] For example, Fig.13 A schematic diagram of the structure of the energy storage system provided in the embodiment of the present application is shown in FIG. Fig.13 As shown, it also includes a weighing device 12, which can be a floor scale. The weighing device 12 is connected to a processor 13. The weighing device is used to measure the mass of the energy storage device in the combustion process at multiple different times and send the data to the processor to determine the second heat release rate of the energy storage device.

[0148] Fig.14 The hardware structure diagram of the electronic device provided in the embodiment of the present application. The electronic device may be integrated with the above processor. Fig.14 As shown, the electronic device 1400 may include a processor 1401 and a memory 1402 storing computer program instructions.

[0149] Specifically, the processor 1401 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0150] The memory 1402 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 1402 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these.

[0151] Where appropriate, the memory 1402 may include removable or non-removable (or fixed) media. Where appropriate, the memory 1402 may be internal or external to the integrated gateway disaster recovery device. In a specific embodiment, the memory 1402 is a non-volatile solid-state memory.

[0152] The memory 1402 may include a read-only memory (ROM), a random access memory (RAM), a disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Therefore, generally, the memory 1402 includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer executable instructions, and when the software is executed (e.g., by one or more processors), it can perform the operations described in any of the methods in the above embodiments. The processor 1401 implements any of the methods in the above embodiments by reading and executing the computer program instructions stored in the memory 1402.

[0153] In one example, the electronic device 1400 may further include a communication interface 1403 and a bus 1404. Fig.14 As shown, the processor 1401, the memory 1402, and the communication interface 1403 are connected via a bus 1404 and communicate with each other.

[0154] The communication interface 1403 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0155] Bus 1404 includes hardware, software or both, and the components of online data traffic billing equipment are coupled to each other. For example, but not limitation, the bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front-side bus (FSB), hypertransport (HT) interconnection, industrial standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnect (PCI) bus, PCI Express (PCIX) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. Where appropriate, bus 1404 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the present application considers any suitable bus or interconnection.

[0156] In addition, in combination with the method in the above embodiment, the embodiment of the present application can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any one of the methods in the above embodiment is implemented.

[0157] An embodiment of the present application also provides a computer program product, including a computer program, which implements any one of the methods in the above embodiments when the computer program is processed and executed.

[0158] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0159] The functional blocks shown in the above structural block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier. "Machine-readable medium" may include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CDROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0160] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0161] Aspects of the present disclosure are described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the functions / actions specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0162] The above are only specific implementation methods of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for determining thermal runaway parameters of an energy storage device, characterized in that: The thermal runaway parameter includes a heat release rate, an explosion vent is provided on the energy storage device, and the method includes: Acquire at least one first image of a flame emerging from the explosion vent; determining an actual height of the flame based on the at least one first image; A first heat release rate when the energy storage device catches fire is determined according to the actual height.

2. The method according to claim 1, characterized in that After determining the first heat release rate of the energy storage device when it is on fire according to the actual height, the method further includes: Obtaining the energy storage value, combustion efficiency and mass loss rate of the energy storage device when the energy storage device catches fire and burns; Determining the combustion heat value of the energy storage device according to the energy storage value; determining a second heat release rate of the energy storage device according to the combustion efficiency, the combustion heat value and the mass loss rate; A target heat release rate of the energy storage device is determined according to the first heat release rate and the second heat release rate.

3. The method according to claim 1, characterized in that Determining the actual height of the flame according to the at least one first image comprises: determining a target image in the at least one first image; Performing binarization processing on the target image to obtain a binarized image of the target image; Determine a first height of a flame tip in the binary image and a second height of a flame root in the binary image according to pixel values ​​of pixels in the binary image; Obtaining a height difference between the first height and the second height; According to the height difference, the actual height of the flame burning at the explosion vent is determined.

4. The method according to claim 3, characterized in that The step of performing binarization processing on the target image to obtain a binarized image of the target image includes: Obtain the color value of each pixel in the target image under each color channel and the weight coefficient corresponding to each color channel; Determine the grayscale value of the pixel point according to the color value of the pixel point in each color channel and the weight coefficient; According to the gray value of each pixel, a binary image of the target image is obtained.

5. The method according to claim 3, characterized in that: The determining, according to the pixel values ​​of the pixels in the binary image, a first height of the flame tip in the binary image and a second height of the flame root in the binary image comprises: Determining a flame outline in the binary image according to pixel values ​​of pixels in the binary image; Determining, according to the flame profile, a first direction of the flame tip toward the flame root and a second direction of the flame root toward the flame tip; Detecting pixel points in the binary image row by row along the first direction to determine a first target row in the binary image, wherein there are target pixel points in the first target row whose pixel values ​​match a preset pixel value range; Detecting pixel points in the binary image row by row along the second direction to determine a second target row in the binary image, wherein there are target pixel points in the second target row whose pixel values ​​match a preset pixel value range; Determining the first height according to the height of the first target row in the binary image; The second height is determined according to the height of the second target row in the binary image.

6. The method according to claim 5, characterized in that The number of the target images is at least two; The determining the first height according to the height of the first target row in the binary image includes: Obtaining the height of the first target row in the binary image of each target image; Determine an average height according to the height of the first target row in each binary image; The first height is determined according to the average height.

7. The method according to any one of claims 3 to 6, characterized in that: The target image includes a reference object, and determining the actual height of the flame burning at the explosion vent according to the height difference includes: Obtaining the image size of the reference object in the binary image; Determining a scaling ratio according to the image size and the actual height of the reference object; According to the scaling ratio and the height difference, an actual height of the flame burning at the explosion vent is determined.

8. The method according to any one of claims 3 to 6, characterized in that: The step of determining a target image in the at least one first image comprises: N target images within a preset time period are selected from the at least one first image, and the preset time period is greater than or equal to a beating period of a flame tip burning at the explosion vent.

9. The method according to any one of claims 1, 3-6, characterized in that: Determining a first heat release rate when the energy storage device is on fire according to the actual height includes: Determine the equivalent diameter of the flame root emerging from the explosion vent according to the equivalent area of ​​the explosion vent; The first heat release rate is determined according to the actual height of the flame and the equivalent diameter.

10. An energy storage system, characterized in that: It comprises an energy storage device, a processor and a camera device, wherein the processor is connected to the camera device, and the energy storage device is provided with an explosion vent; the camera device is used to collect at least one first image of a burning flame emerging from the explosion vent; and the processor is used to execute the method described in any one of claims 1-9.

11. The system according to claim 10, characterized in that The camera device comprises a plurality of cameras, and the plurality of camera devices are arranged at different positions of the energy storage device.

12. The system according to claim 11, characterized in that The camera device and the explosion vent are at the same height.

13. The system according to claim 10, characterized in that It also includes a weighing device connected to the processor, and the weighing device is used to measure the mass of the energy storage device in the combustion process at multiple different times, and send the data to the processor to determine the second heat release rate of the energy storage device.

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