Lithium battery remote monitoring system for urban bus

Abstract

The invention discloses a lithium battery remote monitoring system for an urban bus, and the system comprises an arrangement module which is used for arranging an FBG sensor on the surface of a battery cell and arranging an optical fiber demodulator in a battery cabin; the bump monitoring module is used for identifying and marking a bump cell by means of a fiber grating sensing technology; relates to the technical field of lithium battery monitoring, and can perform real-time monitoring on each battery cell in a battery module, perform early warning and notify related personnel to perform timely processing when monitoring that the battery cell has a bulge phenomenon, further quickly obtain the specific position of the bulge battery cell and the bulge area, and improve the safety of the battery module. According to the method, the swelling degree of the swelling battery cell is judged by collecting the swelling data of the battery cell and analyzing and integrating the collected swelling data, so that targeted treatment measures can be conveniently taken for the battery cells with different swelling degrees, and the problem of resource waste or safety accidents is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery monitoring, and specifically relates to a remote monitoring system for lithium batteries used in urban buses. Background Art

[0002] With the deepening of the environmental protection concept and the growth of the demand for urban sustainable development, the urban bus field is accelerating its transformation towards electrification. Due to its advantages such as high energy density and long cycle life, lithium batteries have become the mainstream power source for urban bus vehicles. However, lithium batteries face many challenges during use, and the phenomenon of cell bulging is particularly prominent. In the prior art, there is a lack of a real-time and accurate monitoring method for the cell bulging phenomenon in urban buses. The collected bulging data often has not been deeply analyzed and effectively integrated, and it is impossible to take targeted treatment measures according to the degree of bulging, which easily leads to problems such as resource waste or safety accidents. In addition, the monitoring devices have not been reasonably arranged in areas with a high frequency of cell bulging based on the previous bulging data of the cells, reducing the accuracy and comprehensiveness of bulging monitoring. To solve the above problems, the present invention proposes a solution. Summary of the Invention

[0003] The present invention aims to solve the problems raised in the above background art. For this purpose, the present invention proposes a remote monitoring system for lithium batteries used in urban buses, including: A layout module for arranging FBG sensors on the surface of the cells and an optical fiber demodulator in the battery compartment; A bulging monitoring module for identifying and marking bulging cells by means of fiber Bragg grating sensing technology; A processing module for obtaining the total area ZMJ of all bulging areas on the bulging cells, obtaining the maximum value of the strain values of each bulging area and marking it as the extreme value jz, comparing the extreme value jz with the preset value LJZ and the total area ZMJ with the preset value ZDZ to judge the degree of bulging of the bulging cells, and taking targeted treatment measures according to the degree of their bulging.

[0004] Preferably, the specific layout method of the FBG sensors in the layout module is as follows: Select any cell, obtain the vertical central axis of each side, arrange b1 FBG sensors at equal intervals along this central axis. Here, the central axis divides the side vertically into two parts. Arrange b2 FBG sensors at the top and bottom of the cell respectively. The FBG sensors at the top are arranged near the electrodes, and the FBG sensors at the bottom are arranged in the central area. Connect all the FBG sensors in series on a single optical fiber. Here, b1 and b2 are both preset values; Perform the same treatment on the remaining cells in the above manner.

[0005] Preferably, the specific arrangement method of the optical fiber demodulator in the arrangement module is as follows: The optical fiber demodulator is arranged in the battery compartment, which is a chamber for placing battery modules. Multiple optical fibers are combined through an optical fiber coupler, and the combined optical fiber is connected to the input port of the optical fiber demodulator. The optical fiber demodulator can receive the optical signals transmitted by multiple optical fibers and analyze and process these signals through corresponding demodulation technologies.

[0006] Preferably, the specific monitoring method in the bulge monitoring module is as follows: The optical fiber demodulator real-time collects the reflected optical signals of the FBG sensors, then converts the collected signals into electrical signals or digital signals for processing, and finally accurately obtains the real-time reflection wavelength of the FBG sensors. , and calculates the wavelength offset monitored by the FBG sensors through a formula . The specific calculation formula is: ; where is referred to as the initial center wavelength; According to the wavelength offset , the strain value on the surface of the battery cell at the FBG sensor can be calculated . The specific calculation formula is: , where is referred to as the photoelastic coefficient of the optical fiber; When , it indicates that bulging occurs on the surface of the battery cell at the FBG sensor. The corresponding battery cell is marked as a bulging battery cell, and a warning signal is generated and sent to the warning unit, where is the preset strain threshold.

[0007] Preferably, the specific processing method in the processing module is as follows: Optionally select a bulging battery cell, and obtain the area that satisfies the condition on this bulging battery cell, and re-mark it as a bulging area; Optionally select a bulging area on the bulging battery cell. Personnel use a three-dimensional laser scanner to perform a full-range scan of the bulging area, obtain the three-dimensional point cloud data of the bulging area, project the three-dimensional point cloud data onto a two-dimensional plane to obtain a series of discrete points, use an interpolation method to generate the boundary of the bulging area, and then calculate the area of the bulging area by using a numerical integration method; In the above manner, the areas of the remaining bulging areas are calculated in the same way and accumulated with each other, and then the total area ZMJ of all bulging areas on this bulging battery cell is obtained; Collect the strain values of each bulging area one by one and sort them in descending order to obtain the strain value ranked first after sorting, and re-mark it as the extreme value jz.

[0008] Preferably, when jz ≥ LJZ or ZMJ ≥ ZDZ, it is determined that the bulged battery cell has a first-level bulging degree.

[0009] Preferably, when jz < LJZ and ZMJ < ZDZ, it is determined that the bulged battery cell has a second-level bulging degree.

[0010] Preferably, the specific arrangement method in the arrangement module is as follows: Based on the same usage environment, collect several bulged battery cells of the same model and structure; According to the actual size specifications of the bulged battery cells, evenly divide each surface of the bulged battery cells into several rectangular grid areas with the same size. Subsequently, number these rectangular grid areas in sequence from left to right and from top to bottom; Among these bulged battery cells, randomly select a bulged area, obtain the grid numbers occupied by the bulged area in the rectangular grid areas, integrate these grid numbers into a number set. In the same way as above, obtain the number sets of the remaining bulged areas, summarize all the number sets, merge them into a list, and obtain the total number ZGS of grid numbers included in the list; Randomly select a grid number, obtain the number of times CS that this grid number appears in the list, and through the formula calculate the proportion BL of this grid number in the total number ZGS; When BL ≥ U, it means that the frequency of this grid number appearing is high, and mark the rectangular grid area corresponding to this grid number as a high-frequency area, where U is a preset proportion threshold; Process the remaining grid numbers in the same way as above, and obtain all the high-frequency areas on the bulged battery cells through calculation.

[0011] Preferably, based on the mapping rule of the grid numbers, accurately lock the rectangular grid areas corresponding to each high-frequency area on the surface of the battery cell to be arranged with FBG sensors, and re-mark them as areas to be arranged; Randomly select a surface on the battery cell. Based on the principle of geometric division, use a cross axis to divide the selected surface into four analysis areas with equal areas, and obtain the total area MJi of the areas to be arranged in each analysis area one by one, where i = 1, 2, 3, 4; When MJi ≥ K1 × A, it is determined that the areas to be arranged show a high distribution density characteristic in the analysis area. When MJi < K1 × A, it is determined that the areas to be arranged show a low distribution density characteristic in the analysis area; Where A is the area of the analysis area and K1 is a preset value.

[0012] Preferably, for the analysis area with high distribution density characteristics, according to the preset spacing rule, the FBG sensors are evenly arranged in a matrix form or a grid form; For the analysis area with low distribution density characteristics, FBG sensors are arranged in each area to be arranged, and the remaining surfaces of the battery cells are processed in the same way as above.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: It can monitor each battery cell in the battery module in real time. When a bulging phenomenon of the battery cell is detected, an alarm is given to notify relevant personnel to deal with it in time. Further, the specific position of the bulging battery cell and the bulging area can be quickly obtained, and the collected bulging data is analyzed and integrated to determine the bulging degree of the bulging battery cell, which is convenient for taking targeted treatment measures for battery cells with different bulging degrees, and avoiding problems such as resource waste or safety accidents; In addition, for the previous bulging data of battery cells of the same model and the same structure, on the bulging battery cells, high-frequency areas with high bulging frequencies are obtained. Subsequently, FBG sensors can be reasonably arranged according to the distribution position and distribution density of the high-frequency areas, so as to realize the all-round bulging monitoring work on the surface of the battery cells and improve the accuracy of monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the principle framework of the present invention; Figure 2 It is a schematic structural diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0016] Embodiment 1

[0017] Please refer to Figure 1 、 2 , this application provides a remote monitoring system for lithium batteries used in urban buses, including; An arrangement module, arranging fiber Bragg grating sensors (hereinafter referred to as FGB sensors) on the surface of each battery cell. FGB sensors of model FBG-1550-0 can be used. Of course, those skilled in the art can select other models according to needs. An optical fiber demodulator is arranged inside the battery compartment. The specific arrangement method is as follows: Select any battery cell, obtain the vertical central axis of each side surface, and along this central axis Perform the same treatment on the remaining battery cells in the above manner; Lay the optical fiber along the edge of the battery cell or arrange it in the pre - reserved wiring groove in the battery compartment, so as not to affect battery assembly and heat dissipation. Here, the battery compartment is the chamber for placing the battery module; In addition, an optical fiber demodulator is also provided in the battery compartment. First, bundle multiple optical fibers through an optical fiber coupler, and then connect the bundled optical fibers to the input port of the optical fiber demodulator. In this way, the optical fiber demodulator can receive the optical signals transmitted by multiple optical fibers and analyze and process these signals through corresponding demodulation techniques; The bulging monitoring module uses fiber Bragg grating sensing technology to monitor the battery cells in real - time. The specific monitoring method is as follows: Before the formal measurement, it is necessary to calibrate the optical fiber demodulator to ensure the accuracy of the measurement results. The calibration process includes using a standard FBG sensor to calibrate the wavelength of the demodulator, so that the wavelength displayed by the optical fiber demodulator is consistent with the actual wavelength; The optical fiber demodulator collects the reflected optical signals of the FBG sensor in real - time, and then converts the collected signals into electrical signals or digital signals for processing, and finally accurately obtains the real - time reflected wavelength of the FBG sensor , and calculate the wavelength shift amount monitored by the FBG sensor through a formula , and the specific calculation formula is: , where refers to the initial central wavelength. When the FBG sensor leaves the factory, the manufacturer will provide technical documents, which clearly mark the initial central wavelength of each FBG sensor ; According to the wavelength shift amount , the strain value on the surface of the battery cell at the FBG sensor can be calculated , and the specific calculation formula is: ; where refers to the photo - elastic coefficient of the optical fiber, which is obtained from the technical specification provided by the optical fiber manufacturer; When , it means that bulging occurs on the surface of the battery cell at the FBG sensor. Mark the corresponding battery cell as a bulging battery cell and generate a warning signal to send to the warning unit, where is the preset strain threshold; The processing module receives the warning signal and transmits the warning signal to the mobile terminal of the relevant personnel. The relevant personnel conduct a differential analysis on the bulging battery cells according to their severity, and then take targeted treatment measures. The specific treatment method is as follows: Select any bulging battery cell, and obtain the area that meets the condition on this bulging battery cell, and re - mark it as the bulging area; Select any bulging area on the bulging battery cell. Personnel use a 3D laser scanner to perform a full - range scan of the bulging area, obtain the 3D point cloud data of the bulging area, project the 3D point cloud data onto a 2D plane to obtain a series of discrete points, use an interpolation method (such as linear interpolation or spline interpolation) to generate the boundary of the bulging area, and then calculate the area of the bulging area by using a numerical integration method (such as triangulation or Green's formula); In the above - mentioned manner, calculate the areas of the remaining bulging areas in the same way and accumulate them mutually, and then obtain the total area ZMJ of all bulging areas on this bulging battery cell; Collect the strain values of each bulging area one by one And perform a descending sort to obtain the strain value ranked first after sorting , and re - mark it as the extreme value jz; When jz≥LJZ or ZMJ≥ZDZ, it is determined that the bulging degree of this bulging battery cell is at the first - level. At this time, personnel will replace this bulging battery cell and conduct a comprehensive inspection and analysis of other battery cells in the battery module to ensure the safe operation of the system; When jz<LJZ and ZMJ<ZDZ, it is determined that the bulging degree of this bulging battery cell is at the second - level. At this time, personnel will perform local repair on this bulging battery cell, such as readjusting the mechanical structure inside the battery cell. Here, LJZ and ZDZ are both preset values, which are specifically set according to the design and safety standards of the battery.

[0018] Embodiment 2

[0019] In the specific implementation process of this embodiment, compared with Embodiment 1, the specific difference is that another arrangement method in the arrangement module is provided. The specific improvement is as follows: Based on the same usage environment, collect several bulging battery cells of the same model and structure; According to the actual size specifications of the bulging battery cells, evenly divide each surface of the bulging battery cells into several rectangular grid areas with the same size. Subsequently, number these rectangular grid areas in sequence from left to right and from top to bottom; Among these bulging battery cells, select any bulging area, obtain the grid numbers occupied by the bulging area in the rectangular grid areas, integrate these grid numbers into a number set. In the same way as above, obtain the number sets of the remaining bulging areas, summarize all the number sets, merge them into a list, and obtain the total number ZGS of grid numbers included in the list; Select any grid number, obtain the number of times CS that this grid number appears in the list, and calculate the proportion BL of this grid number in the total number ZGS through the formula ; When BL≥U, it indicates that the grid number appears with a high frequency. The rectangular grid area corresponding to this grid number is marked as a high-frequency area, where U is a preset proportional threshold. Process the remaining grid numbers in the same way. After calculation, all high-frequency areas on the bulging battery cell are obtained. Based on the mapping rule of the grid number, on the surface of the battery cell where the FBG sensors are to be arranged, accurately lock the rectangular grid areas corresponding to each high-frequency area one by one, and re-mark them as areas to be arranged. Randomly select one face on the battery cell. Based on the principle of geometric division, use a cross axis to divide the selected face into four analysis areas with equal areas. Obtain the total area MJi of the areas to be arranged in each analysis area one by one, where i = 1, 2, 3, 4. When MJi≥K1×A, it is determined that the areas to be arranged show a high distribution density characteristic in the analysis area. When MJi<K1×A, it is determined that the areas to be arranged show a low distribution density characteristic in the analysis area. Where A is the area of the analysis area and K1 is a preset value. For the analysis area with a high distribution density characteristic, arrange the FBG sensors in a matrix form or a grid form evenly according to the preset spacing rule. To ensure the comprehensiveness of monitoring coverage, the number of FBG sensors arranged here is more than the number of areas to be arranged. For the analysis area with a low distribution density characteristic, arrange FBG sensors in each area to be arranged. Process the remaining faces on the battery cell in the same way.

[0020] Some of the data in the above formula are numerically calculated after removing their dimensions. At the same time, the content not described in detail in this specification belongs to the prior art well known to those skilled in the art.

[0021] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A remote monitoring system for lithium batteries used in urban buses, characterized in that, include: Arrangement module, used to arrange FBG sensors on the surface of the battery cell and arrange optical fiber demodulators in the battery compartment; Bulging detection module, used to identify and mark bulging cells using fiber grating sensing technology; A processing module, configured to obtain the total area ZMJ of all bulging regions on a bulging battery cell, and obtain the maximum value of the strain values of each bulging region and mark it as the extreme value jz, and compare the extreme value jz with a preset value LJZ, and compare the total area ZMJ with a preset value ZDZ, so as to judge the bulging degree of the bulging battery cell, and take targeted treatment measures according to its bulging degree; The maximum value is marked as the extreme value jz, and the extreme value jz is compared with the preset value LJZ, and the total area ZMJ is compared with the preset value ZDZ, so as to judge the bulging degree of the bulging battery cell, and take targeted treatment measures according to its bulging degree; The specific processing method in the processing module is: Optionally select a bulged battery cell, and obtain the area on the bulged battery cell that meets the condition, and re-label it as the bulged area; A bulge area is randomly selected on the bulged battery cell. A 3D laser scanner is used to perform a full-scale scan of the bulge area, obtaining 3D point cloud data of the bulge area. The 3D point cloud data is projected onto a 2D plane to obtain a series of discrete points. The boundary of the bulge area is generated using an interpolation method, and the area of the bulge area is then calculated using a numerical integration method. According to the above method, the areas of the remaining bulge areas are calculated in the same way and added together to obtain the total area ZMJ of all bulge areas on the bulge cell. Collect the strain values of each bulging area one by one And perform a descending sort to obtain the strain value ranked first after sorting , and mark it as the extreme value jz again; When jz≥LJZ or ZMJ≥ZDZ, the bulging cell is judged to be level one bulging; When jz<LJZ and ZMJ<ZDZ, it is determined that the bulging battery cell is at the second level of bulging.

2. The remote monitoring system for lithium batteries used in urban buses according to claim 1, characterized in that, The specific arrangement of the FBG sensors in the arrangement module is as follows: Select any cell and determine the vertical center axis of each side. Arrange b1 FBG sensors at equal intervals along the center axis. The center axis divides the side vertically into two equal parts. Arrange b2 FBG sensors at the top and bottom of the cell, with the top FBG sensor near the electrode and the bottom FBG sensor in the center. Connect all FBG sensors in series on a single optical fiber. Here, b1 and b2 are preset values. Perform the same process on the remaining cells in the same manner as above.

3. The remote monitoring system for lithium batteries used in urban buses according to claim 1, characterized in that, The specific arrangement of the optical fiber demodulator in the arrangement module is as follows: The fiber optic demodulator is placed in the battery compartment, which is the cavity where the battery module is placed. Multiple optical fibers are bundled together through a fiber optic coupler, and the bundled optical fibers are connected to the input port of the fiber optic demodulator. The fiber optic demodulator can then receive optical signals from multiple optical fibers and analyze and process these signals through corresponding demodulation technology.

4. The remote monitoring system for lithium batteries used in urban buses according to claim 1, characterized in that, The specific monitoring method in the bulge monitoring module is: The reflected optical signal of the FBG sensor is collected in real time by the fiber optic demodulator, and then the collected signal is converted into an electrical signal or a digital signal for processing, and finally the real-time reflection wavelength of the FBG sensor is accurately obtained. The wavelength shift monitored by the FBG sensor is calculated through a formula. The specific calculation formula is as follows: where is referred to as the initial central wavelength; According to the wavelength offset , the strain value on the surface of the battery cell at the FBG sensor can be calculated , and the specific calculation formula is as follows: ; where refers to the photoelastic coefficient of the optical fiber; When it indicates that the surface of the battery cell at the FBG sensor bulges. Mark the corresponding battery cell as a bulged battery cell and generate a warning signal to send to the warning unit, where is a preset strain threshold value.

5. The remote monitoring system for lithium batteries used in urban buses according to claim 1, characterized in that, The specific arrangement method in the arrangement module is: Based on the same usage environment, collect several bulging batteries of the same model and structure; According to the actual size specifications of the bulged battery cell, each surface of the bulged battery cell is evenly divided into several rectangular grid areas of the same size. Then, these rectangular grid areas are numbered in sequence from left to right and from top to bottom; Among these bulging cells, select any bulging area and obtain the grid number occupied by the bulging area in the rectangular grid area. These grid numbers are integrated into a number set. In the same way as above, the number sets of the remaining bulging areas are obtained. All the number sets are summarized and merged into a list to obtain the total number of grid numbers contained in the list, ZGS. Optionally select a grid number, obtain the number of occurrences CS of this grid number in the list, and calculate the proportion BL of this grid number in the total number ZGS through the formula ; When BL≥U, it means that the grid number appears frequently, and the rectangular grid area corresponding to the grid number is marked as a high-frequency area, where U is a preset ratio threshold; According to the above method, the remaining grid numbers are processed in the same way, and all high-frequency areas on the bulging battery cell are obtained through calculation.

6. The remote monitoring system for lithium batteries used in urban buses according to claim 5, characterized in that, Based on the mapping rule of grid numbering, on the surface of the battery cell where the FBG sensors are to be arranged, accurately lock the rectangular grid areas corresponding one by one to each high-frequency area, and re-mark them as the areas to be arranged; Randomly select one surface on the battery cell. Based on the principle of geometric segmentation, use the cross axis to divide the selected surface into four analysis areas with equal areas, and obtain the total area MJi of the areas to be arranged in each analysis area one by one, where i = 1, 2, 3, 4; When MJi ≥ K1×A, it is determined that the areas to be arranged show a high distribution density characteristic in the analysis area. When MJi < K1×A, it is determined that the areas to be arranged show a low distribution density characteristic in the analysis area; where A is the area of the analysis area and K1 is a preset value.

7. The remote monitoring system for lithium batteries used in urban buses according to claim 6, characterized in that, For the analysis areas with high distribution density characteristics, arrange the FBG sensors in a matrix form or a grid form uniformly according to the preset spacing rule; For the analysis areas with low distribution density characteristics, arrange the FBG sensors in each area to be arranged. Process the remaining surfaces on the battery cell in the same way as above.

Images