A method for obtaining a key detection area of an electric core, a battery intelligent safety detection method, device, system and vehicle

Abstract

The application discloses a method for obtaining a key detection area of an electric core. The method comprises the following steps: obtaining pressure data of a first surface of the electric core in one or more charging and discharging cycles under preset conditions, forming a pressure distribution map of the first surface, and determining a key detection area according to the pressure distribution map. Further, the application also discloses a battery intelligent safety detection method, which comprises the following steps: obtaining pressure data of a first surface of an electric core in a battery assembly detected by a pressure detection unit, analyzing and processing pressure data of a key detection area in the first surface, and judging whether the electric core has a safety hidden danger according to a preset standard. Further, the application also discloses a battery intelligent safety detection device, a system and a vehicle. Through the application, the accuracy of battery safety detection can be improved, and early warning of battery health problems can be realized.

Description

Technical Field

[0001] This application belongs to the field of battery testing, and specifically relates to a method for obtaining key testing areas of battery cells, a battery intelligent safety testing method, device, system, and vehicle. Background Technology

[0002] With the rise of new energy vehicles, traditional automakers are also accelerating their investment in this area. Currently, most new energy vehicles use rechargeable batteries for power. However, the recurring incidents of spontaneous combustion and explosions of batteries have brought the safety and stability of new energy vehicle batteries to the forefront of public opinion, becoming a major concern within the industry, and safety issues are receiving increasing attention. Current management and testing of power batteries typically focus on monitoring and managing their operating status, including temperature, voltage, current, and chemical gas detection. However, safety monitoring from these dimensions is still insufficient and often fails to detect potential safety hazards in a timely manner.

[0003] Currently, the method of monitoring battery safety through pressure sensors usually involves setting up single or multiple pressure sensors on the battery to detect the expansion of the battery. However, since the actual working conditions of the battery are quite complex, the places where expansion and deformation occur may not be the places predicted in advance. Therefore, using single or multiple pressure sensors to detect battery expansion often results in missed detections or inaccurate detection results. Summary of the Invention

[0004] The purpose of this application is to provide a method for obtaining key detection areas of battery cells, a battery intelligent safety detection method, device, system, and vehicle, so as to improve the accuracy of battery safety detection and achieve early warning of battery health problems.

[0005] The technical solution of this application mainly includes the following aspects:

[0006] The first aspect of this application provides a method for obtaining key detection areas of a battery cell, mainly comprising: acquiring pressure data of a first surface of the battery cell within one or more charge-discharge cycles under preset conditions; forming a pressure distribution map of the first surface; determining key detection areas based on the pressure distribution map; the pressure data being obtained by a pressure detection unit arranged on the first surface; the pressure detection unit comprising a thin-film sensing sheet and a data acquisition device electrically connected to the thin-film sensing sheet.

[0007] Furthermore, this application also discloses optional methods for defining the first surface; methods for determining key detection areas, etc.

[0008] The second aspect of the present application provides a battery intelligent safety detection method, mainly comprising: obtaining pressure data of a first surface of an electric core in a battery assembly detected by a pressure detection unit; analyzing and processing pressure data of a key detection area in the first surface; judging whether the electric core has a safety hazard according to a preset standard; wherein the key detection area is obtained by the method of the first aspect or any one of the optional solutions.

[0009] Further, the present application also discloses an optional setting method of the preset standard and a method of judging whether the electric core has a safety hazard based on the preset standard.

[0010] The third aspect of the present application provides a battery intelligent safety detection device, mainly comprising a pressure detection module and a control module, the pressure detection module comprising a controller and a plurality of pressure detection units not less than the number of a battery module, the pressure detection unit having a thin film sensing sheet and a data collector; the input end of the data collector is electrically connected with the thin film sensing sheet, and the output end is communicatively connected with the controller; the control module comprises a BMS communicatively connected with the controller; the thin film sensing sheet is configured to change at least one electrical parameter when subjected to pressure, and the data collector is used to convert the electrical parameter data into pressure data and transmit the pressure data to the controller; the controller or the BMS is used to realize the method of obtaining the key detection area of the electric core according to the first aspect of the present application or any one of the optional solutions thereof, and / or is used to realize the battery intelligent safety detection method according to the second aspect of the present application or any one of the optional solutions thereof.

[0011] The fourth aspect of the present application provides a vehicle, mainly comprising a driving device, a battery and the battery intelligent safety detection device according to the third aspect.

[0012] The fifth aspect of the present application provides a battery intelligent safety detection system, mainly comprising a central control system and a plurality of battery intelligent safety detection devices; the battery intelligent safety detection device comprises a pressure detection module and a control module, the pressure detection module comprising a controller and a plurality of pressure detection units not less than the number of a battery module, the pressure detection unit having a thin film sensing sheet and a data collector; the input end of the data collector is electrically connected with the thin film sensing sheet, and the output end is communicatively connected with the controller; the control module comprises a BMS communicatively connected with the controller; the thin film sensing sheet is configured to change at least one electrical parameter when subjected to pressure, and the data collector is used to convert the electrical parameter data into pressure data and transmit the pressure data to the controller; the central control system is communicatively connected with the BMS; the central control system is used to realize the method of obtaining the key detection area of the electric core according to the first aspect of the present application or any one of the optional solutions thereof, and / or is used to realize the battery intelligent safety detection method according to the second aspect of the present application or any one of the optional solutions thereof.

[0013] The application has the following beneficial effects:

[0014] 1、In the application, since the thin film sensing sheet can cover the entire area of the first surface of the battery cell, the pressure data of the entire first surface can be obtained through the thin film sensing sheet. The maximum expansion force of the first surface of the battery cell during charging and discharging can be obtained through the pressure detection unit, and the position where the maximum expansion force occurs on the first surface can be located. In combination with the charging and discharging data of the battery cell, the time when the maximum expansion force occurs on the first surface can also be located according to the electric quantity of the battery cell. In the prior art, the pressure distribution of a surface cannot be obtained through single-point detection, even if many points are arranged on a surface, the accurate surface pressure distribution and the average surface pressure cannot be obtained, and thus the surface prone to expansion cannot be obtained, and the position where the maximum expansion force occurs on the surface cannot be accurately obtained. In the application, the thin film pressure sensor is used to comprehensively cover the outer surface of the battery cell to detect the pressure change of each surface of the battery cell, and the surface prone to expansion risk of the battery cell can be objectively and accurately located. Through the detection and analysis of the surface, the key detection points or the key detection areas can be intuitively and accurately obtained through the generated pressure distribution diagram, which is convenient for users to identify and avoids misjudgment caused by manual identification of the key detection areas.

[0015] 2、As can be understood, when the battery expands, it does not expand at a single point, but expands in a certain area, and the area where the expansion is serious is at risk of damage. If only the pressure of a single point is concerned whether it exceeds the set threshold, the area that does not exceed the set threshold may be missed, but these areas are at risk of damage, which may lead to inaccurate detection results. In the application, the first surface is divided into different areas, and the area is taken as the detection object and the total pressure in the area is taken as the judgment standard. The entire area of the first surface is detected, and the detection mode covering the first surface overcomes the shortcomings of taking a point as the detection object, and can more accurately and effectively detect the key detection areas of the first surface that need to be concerned. In addition, the CV values of the areas are calculated to avoid the omission of the key detection areas.

[0016] 3、The battery intelligent safety detection device detects the pressure of the entire surface of the battery cell to avoid the omission of single-point detection or multi-point detection, further improves the reliability of the detection results, and improves the safety during the use of the battery.

[0017] 4、The battery intelligent safety detection device sets at least one pressure detection unit on each battery module, each pressure detection unit can detect the expansion force of the battery cell in each battery module, and thus the expansion force detection of the battery module is comprehensively covered. In addition, each data collector is in communication connection with the BMS, and the expansion force of the battery cell in each battery module can be analyzed and detected in real time through the BMS system, which is more convenient and efficient.

[0018] 5、The application can monitor the pressure data of the key detection area in real time according to the demand, monitor the non-key detection area according to the preset frequency, and correct the key detection area combined with the actual detection result, and include the new expansion risk point in the key detection area.

[0019] 6、The application takes the standard pressure change curve and the non-standard pressure change curve of each key detection area and non-key detection area as the preset standard, compares the pressure distribution curve of the key detection area and the non-key detection area with the preset standard, and determines whether the battery cell has an expansion risk, which is more objective and accurate in detecting the safety status of the battery. Moreover, through the comparison of the curves, it can also predict whether the battery will have a safety hazard, further improving the reliability, practicality and safety.

[0020] 7、The central control system in the application can be connected with a plurality of battery intelligent safety detection devices, the central control system obtains the battery cell pressure data detected by the battery intelligent safety detection device, and corrects the key detection area of the battery cell according to the battery cell pressure data and the method for obtaining the key detection area of the battery cell, further improving the reliability and accuracy of the battery safety detection. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or exemplary technical descriptions will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 It is a structural schematic diagram of a battery assembly;

[0023] Figure 2 It is a schematic diagram of an expansion force detection system module provided by the embodiments of the present application;

[0024] Figure 3 It is a structural schematic diagram of a pressure detection unit provided by the embodiments of the present application;

[0025] Figure 4 It is a schematic diagram of the connection mode between the BMS, the controller and the data collector provided by the embodiments of the present application;

[0026] Figure 5 It is an installation schematic diagram of a pressure detection unit provided by the embodiments of the present application;

[0027] Figure 6 It is a flowchart of the method for obtaining the key detection area of the battery cell provided by the embodiments of the present application;

[0028] Figure 7 An installation schematic diagram of a thin film sensing sheet provided for an embodiment of the present application;

[0029] Figure 8 A key detection area division schematic diagram provided for an embodiment of the present application Figure 1 ;

[0030] Figure 9 A key detection area division schematic diagram provided for an embodiment of the present application Figure 2 ;

[0031] Figure 10 A schematic diagram of the correction of the key detection area provided for an embodiment of the present application;

[0032] Figure 11 A flow schematic diagram of a battery intelligent safety detection method provided for an embodiment of the present application;

[0033] Figure 12 A module schematic diagram of a vehicle provided for an embodiment of the present application;

[0034] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of this application. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0035] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0036] It should be noted that when an element is referred to as being "arranged on" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0037] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited. The meaning of "several" is one or more, unless otherwise specifically limited.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] Throughout the specification, reference to "one embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, the appearance of the phrase "in one embodiment" or "in some embodiments" in various places throughout the specification are not all referring to the same embodiment. In addition, in one or more embodiments, specific features, structures, or characteristics can be combined in any suitable manner.

[0040] Please refer to Figure 1 , first of all, the battery assembly is described, the battery assembly is stacked by one or more than two battery modules, each group of battery modules contains at least one battery cell. The battery intelligent safety detection device at least includes an expansion force monitoring system, the expansion force monitoring system is used for monitoring the expansion force change condition of the battery cell in the battery assembly in real time, and issuing an alarm when the expansion force change of the battery cell is abnormal. Of course, the battery intelligent safety detection device can also include a temperature detection system for detecting the temperature of the battery, a gas concentration detection system for detecting whether there is electrolyte leakage in the battery, etc.

[0041] Please refer to Figure 2 and Figure 3 , specifically, the expansion force monitoring system is composed of a pressure detection module and a control module. Among them, the control module mainly includes BMS (BATTERY MANAGEMENT SYSTEM, battery management system); the pressure detection module mainly includes a pressure detection unit and a controller in communication connection with the BMS, the pressure detection unit is arranged in the battery module to detect the expansion force change of the battery cell in the battery module, and the controller is in communication connection with the pressure detection unit to obtain the detection result through the pressure detection unit. As an embodiment, the controller can directly transmit the obtained detection result to the BMS, and analyze the detection result through the BMS; as another embodiment, the detection result is analyzed through the controller, and the analysis result is transmitted to the BMS system.

[0042] The controller and the BMS and the controller and the data collector can be connected in communication through CAN (Controller Area Network), and can also be connected in communication through a 485 bus interface or other means.

[0043] Specifically, the pressure detection unit comprises a thin film sensing sheet and a data collector, the thin film sensing sheet is set to change at least one electrical parameter when being pressed, and the data collector is electrically connected with the thin film sensing sheet to receive the changed electrical parameter data and convert the changed electrical parameter data into pressure data.

[0044] In the present application, one or more groups of pressure detection units can be provided, and multiple groups of pressure detection units can be provided in one battery module to detect the expansion force change of different battery cells in the battery module, or the multiple groups of pressure detection units can be provided in different battery modules to detect the expansion force change of battery cells in different battery modules. As an embodiment, when the battery assembly is formed by stacking at least two groups of battery modules, the pressure detection module comprises at least two groups of pressure detection units, and the at least two groups of pressure detection units are arranged in different battery modules to detect the expansion force change of battery cells in different battery modules. In the present application, as an embodiment, the number of pressure detection units is not less than the number of battery modules, so that at least one pressure detection unit is provided on each battery module, which can realize pressure detection of all battery modules.

[0045] It can be understood that when multiple groups of pressure detection units are provided, the controller can simultaneously obtain the detection results of the multiple groups of pressure detection units, or can sequentially obtain the detection results of the multiple groups of pressure detection units. Please refer to Figure 4 As an embodiment, the data collectors of the multiple groups of pressure detection units are connected in parallel through data transmission lines and are electrically connected with the controller, and the controller obtains the pressure data of each data collector at this time. Please refer to Figure 4 As another embodiment, the data collectors of the multiple groups of pressure detection units are electrically connected with the controller through data transmission lines, so that the controller can simultaneously or respectively obtain the pressure data of each data collector.

[0046] It can be understood that by providing at least one pressure detection unit on each battery module, each pressure detection unit can detect the expansion force of each battery cell in the battery module, thereby realizing comprehensive coverage of the expansion force detection of the battery assembly, and each data collector is in communication with the controller, and the expansion force of each battery cell in the battery module can be analyzed and detected in real time by the controller combined with the BMS, and the BMS system issues an alarm when the BMS system analyzes that the battery module has a safety hazard, so that the detection process is more convenient and efficient.

[0047] Further, since each pressure detection unit is arranged in different battery module, each data collector is arranged corresponding to different battery cell, and different digital number can be set for different data collector to realize one-to-one correspondence between data collector and battery cell. In this way, when the BMS or controller detects the battery cell with abnormal expansion, the data collector providing corresponding data can be obtained through the BMS or controller, and the battery cell with problem can be accurately located through the digital number of the data collector, which has high practicality and timeliness.

[0048] It can be understood that a group of pressure detection units can be arranged in any battery module, or multiple groups of pressure detection units can be arranged. The thin film sensing sheet of the pressure detection unit can be clamped and arranged between two battery cells, or clamped and arranged between the battery cell and the shell mounting the battery cell.

[0049] Referring to Figure 5 , as an embodiment, three groups of pressure detection units are arranged in the battery module, and the three groups of pressure detection units are arranged at the two opposite ends and the middle position of the battery module. Among them, the thin film sensing sheet should cover at least one main expansion surface of the battery cell, and in this embodiment, the thin film sensing sheet covers the surface of the battery cell prone to expansion.

[0050] It can be understood that when the battery intelligent safety detection device is used to monitor the expansion change of the battery cell in the battery assembly in real time, each data collector obtains the pressure data of the corresponding battery cell through the corresponding thin film sensing sheet, each data collector transmits the detected pressure data to the controller, and the controller can transmit each pressure data to the BMS to analyze each pressure data through the BMS and judge the health condition of each battery cell to make effective response processing. Of course, the controller can also collect and analyze each pressure data, and transmit the analysis result to the BMS to judge the health condition of each battery cell through the BMS to make effective response processing. That is, through the above-mentioned manner, the problem involving the safety hidden danger of the battery cell can be timely warned.

[0051] Please refer to Figure 6 , the application also provides a method for obtaining the key detection area of the battery cell, mainly comprising:

[0052] A1, detecting the expansion force of each surface of the battery cell during charging and discharging through the pressure detection unit under the preset condition, and determining at least one surface of the battery cell prone to expansion (defining the surface as the first surface) according to the detection result.

[0053] Combined with Figure 7 , during detection, multiple thin film sensing sheets are respectively pasted on the surface of each surface of the battery cell, so that the expansion force of each surface of the battery cell during charging and discharging can be obtained through each thin film sensing sheet.

[0054] As an implementation, the method for determining the surface prone to swelling can be: obtaining the maximum pressure value of each surface of the battery during one or more charge and discharge cycles of the battery, and the surface with the maximum value is the surface prone to swelling; as another implementation, obtaining the maximum pressure value of each surface of the battery during one or more charge and discharge cycles of the battery, and setting the surface with the maximum pressure value exceeding a set threshold as the surface prone to swelling.

[0055] The preset condition can include the ambient temperature of the battery, the initial pressure on the battery, the installation clamp of the battery to be detected, etc. The preset condition is set to simulate the real use scenario of the battery in use, for example, the preset condition can be set as: under the condition of 40 degrees of ambient temperature, a certain initial pressure is applied to the battery to be detected by the tooling clamp, the battery is charged and discharged under this condition, and the swelling force of each surface of the battery during charging and discharging is detected by the pressure detection unit.

[0056] A2, detecting the pressure data of the first surface of the battery during charging and discharging under the preset condition by the pressure detection unit to form a pressure distribution map of the first surface (as shown in Figure 8 According to the pressure distribution map, the key detection area and / or the key detection point are determined.

[0057] It can be understood that, since the film sensing sheet can cover the entire area of the first surface, the pressure data of the entire first surface can be obtained through the film sensing sheet. The maximum swelling force of the first surface of the battery during charging and discharging can be obtained by the pressure detection unit, and the position of the maximum swelling force on the first surface can be located. At the same time, according to the battery capacity and the charge and discharge data of the battery, the time when the maximum swelling force occurs on the first surface can be located. In the prior art, the pressure distribution of a surface cannot be obtained by single-point detection, even if many points are arranged on a surface, the accurate surface pressure distribution and the average surface pressure cannot be obtained, and thus the surface prone to swelling cannot be obtained, and the position of the maximum swelling force on the surface cannot be accurately obtained. In the present application, the film type pressure sensor fully covers the outer surface of the battery, detects the pressure change of each surface of the battery, and objectively and accurately locates the surface prone to swelling of the battery. Further, through the detection and analysis of the entire surface, the key detection point or the key detection area can be intuitively and accurately obtained through the generated pressure distribution map, and according to the battery capacity and the charge and discharge data of the battery, the time when the maximum swelling force occurs on the key detection point or the key detection area on the first surface can be located, which is convenient for users to identify and avoids misjudgment caused by manual identification of the key detection area.

[0058] The judgment method of the key detection point is based on the pressure data of the whole first surface. One judgment method can be that during one or several charge and discharge cycles of the battery cell, the pressure of the whole first surface is monitored in real time, and whether the difference between the maximum pressure value and the minimum pressure value of each point in the first surface exceeds a set threshold value is judged. If it exceeds, the point is taken as the key detection point. The threshold value can be set according to the pressure acting on the battery cell shell when the maximum elastic deformation of the battery cell shell occurs, and is usually less than the pressure value. The maximum elastic deformation is usually related to the material, thickness and structure, and can be calculated or obtained through experiments. The judgment method of the key detection point can also be that during one or several charge and discharge cycles of the battery cell, the average pressure value of the whole first surface and the average pressure value of each point are calculated, and then the point in the first surface whose average pressure exceeds the average pressure value of the whole surface is taken as the key detection point.

[0059] The judgment method of the key detection area can be that the key detection points are obtained based on the above method, and the area within a certain range centered on the key detection point is divided into the key detection area. The size of the area can be set according to the size of the battery cell shell; or the area within a certain diameter range centered on the key detection point can be divided into the key detection area; or the key detection area can be divided according to the distribution of the key detection points.

[0060] Referring to Figure 9 In other embodiments, the key detection points can not be obtained, and the key detection area can be directly obtained. The judgment method of the key detection area can be that the film sensing sheet is first divided into different sheet areas, for example, the film sensing sheet is divided into MxN equal sheet areas (wherein M and N can be the same or different positive integers), the pressure data of each sheet area is obtained, the sum of the pressures of each sheet area (i.e. the total pressure of each sheet area) during one or more charge and discharge cycles of the battery cell is calculated, and then whether the total pressure of each sheet area exceeds a set pressure threshold value is judged. If it exceeds, the sheet area is determined as the key detection area. Alternatively, the total pressure of the first surface at each time during one or more charge and discharge cycles of the battery cell can be calculated, the time when the total pressure of the first surface is the largest is located, and whether the real-time pressure of each sheet area at the time exceeds a set pressure threshold value is obtained and judged. If it exceeds, the sheet area is determined as the key detection area. The present application does not specifically limit the way of determining the key area.

[0061] In view of the fact that the total pressure of some regions may not exceed the set pressure threshold, but the pressure fluctuates greatly in the region, and there are regions with high pressure and regions with low pressure. In order to avoid missing the region with high pressure, the CV value (coefficient of variation) of the region whose total pressure does not exceed the set pressure threshold is calculated after the above steps, and when the CV value of a certain region exceeds the set value, the region is also determined as a key detection region. Through the above method, the accuracy of the key detection region division can be further improved, and the omission of the key detection region can be avoided.

[0062] In the present application, the CV value calculation formula of each region is:

[0063] Wherein, SD is the pressure standard deviation of the region, and the SD calculation formula is:

[0064]

[0065] In the formula, X i represents the pressure value of the i-th sample in the region, i=1, 2,..., N; represents the average pressure value of the N samples in the region; N is the number of samples used.

[0066] Wherein, MN is the average pressure value of the region, and the MN calculation formula is:

[0067]

[0068] In the formula, X i represents the pressure value of the i-th sample in the region, and N is the number of samples used.

[0069] It can be understood that in the present application, the total pressure in the region is used as the judgment standard because the battery expansion occurs in a region rather than a point, and the region with serious expansion has the risk of damage. If only the pressure of a certain point is concerned whether it exceeds the set threshold, the region which does not exceed the set threshold may be easily missed, but these regions are prone to damage, which may lead to inaccurate detection results. The present application divides the first surface into different regions, takes the region as the monitoring object, and takes the total pressure in the region as the judgment standard. The detection is for the entire region of the first surface, and the detection method covering the first surface overcomes the shortcomings of taking a point as the detection object, and can more accurately and effectively detect the key detection region of the first surface. It can be understood that the other regions outside the key detection region of the first surface can be defined as non-key detection regions.

[0070] Please refer to Figure 10As an improvement, the method can be used to determine the key detection area of the battery cell during use, and can also correct the key detection area of the battery cell in the experiment according to the collected pressure detection data of the battery cell in actual use. For example, by analyzing the pressure detection data of the battery cell in actual use, it is found that the average pressure value of the non-key detection area divided by the experiment exceeds the set threshold value, and the area should be modified to the key detection area. As an embodiment, by analyzing the pressure detection data of the battery cell in actual use in a certain charge and discharge cycle, if the total pressure value of the non-key detection area exceeds the threshold value, the non-key detection area is modified to the key detection area. As another embodiment, by analyzing the pressure detection data of the battery cell in actual use in a plurality of charge and discharge cycles, if the total pressure value of the non-key detection area exceeds the threshold value in each charge and discharge cycle, the non-key detection area is modified to the key detection area.

[0071] It can be understood that the actual use of the battery is relatively complex, and there are many factors affecting the expansion of the battery. By analyzing the pressure detection data of the battery cell in actual use to correct the key detection area, the accuracy of the obtained key detection area can be ensured.

[0072] The application also provides a battery intelligent safety detection system, which comprises the battery intelligent safety detection device and a central control system. The central control system can be connected with the battery intelligent safety detection device. The central control system can obtain the pressure data of the battery cell detected by the battery intelligent safety detection device, and can analyze and correct the key detection area of the battery cell according to the pressure data of the battery cell.

[0073] Please refer to Figure 11 The application also provides a battery intelligent safety detection method, which can be used to monitor the expansion force change of the battery cell in the battery assembly in real time, and mainly comprises:

[0074] Step 1: Collect the pressure data on the corresponding battery cell through each pressure detection unit, and transmit the detected pressure data to the controller. The controller analyzes and processes the pressure data of the key detection area or the key detection area and the non-key detection area.

[0075] It should be noted that the key detection area of the battery cell in the present application is the area of the battery cell that is prone to swelling during use. The non-key detection area is the area outside the key detection area on the surface of the battery cell. The key detection area of the battery cell can be obtained according to the foregoing experimental examples, or can be obtained through a large amount of real data during use of the battery cell, or can be obtained according to the experimental results combined with real data during use of the battery cell.

[0076] As an embodiment, each pressure detection unit collects pressure data on the corresponding battery cell in real time, and the controller analyzes the pressure data of the key detection area in real time and draws a pressure change curve graph of the key detection area. As another embodiment, each pressure detection unit can collect pressure data on the corresponding battery cell at a preset frequency, and the controller analyzes the pressure data of the key detection area after obtaining the pressure data and draws a pressure change curve graph of the key detection area. The pressure change curve graph reflects the trend of the swelling force of each area on the surface of the battery cell with the change of the battery cell capacity under normal charging and discharging conditions.

[0077] In other embodiments, the controller can also analyze the pressure data of the non-key detection area at a preset frequency and draw a pressure change curve graph of the non-key detection area. The preset frequency can be set by itself, and as an embodiment, it can be set to analyze the non-key detection area every 20 minutes, and collect 40 minutes of data for each analysis; or it can be set to analyze the non-key detection area every 10 minutes, and collect 40 minutes of data for each analysis. Of course, when each pressure detection unit collects pressure data on the corresponding battery cell in real time, the controller can also analyze the pressure data of the non-key detection area in real time and draw a pressure change curve graph of the non-key detection area. The data detection frequency of the key or non-key detection area is not limited in the present application.

[0078] Step 2: Determine whether there is abnormal data in each pressure data according to the preset standard.

[0079] Specifically, the method for determining whether there is abnormal data in each pressure data according to the preset standard is as follows:

[0080] Compare the pressure change curve graph of the key detection area with the standard pressure change curve graph of the key detection area to determine whether the key detection area has or is about to have a safety hazard.

[0081] As an implementation, in the same electric quantity change interval, the slope change of the pressure change curve to be detected is compared with the slope change of the pressure curve under the standard condition, and whether the safety hazard occurs or is about to occur in the key detection area is judged according to the comparison result. Specifically, in the case of normal charging and discharging of the battery cell, the change of the expansion force of the key detection area and the non-key detection area of the battery cell in one or more charging and discharging cycles can be obtained by detecting the pressure on the surface of the battery cell, and a curve graph of the change of the expansion force with the electric quantity is obtained, which is defined as a standard pressure change curve. The standard curvature change curve of the standard pressure change curve can be obtained by derivation. During detection, the pressure change curve of the key detection area is obtained, and the pressure change curve is derived to obtain the curvature change curve to be detected in the key detection area. In the same electric quantity change interval, the value corresponding to the standard curvature change curve of the key detection area is compared with the value corresponding to the curvature change curve to be detected. When the value corresponding to the curvature change curve is greater than the value corresponding to the standard curvature change curve, and the difference between the value corresponding to the curvature change curve and the value corresponding to the standard curvature change curve is greater than a set threshold, it is judged that the safety hazard occurs or is about to occur in the key detection area.

[0082] As another implementation, in the same electric quantity change interval, the value corresponding to the pressure change curve of the key detection area is compared with the value corresponding to the standard pressure change curve of the key detection area. When the value corresponding to the pressure change curve is greater than the value corresponding to the standard pressure change curve, and the difference between the value corresponding to the pressure change curve and the value corresponding to the standard pressure change curve is greater than a set threshold, it is judged that the safety hazard occurs or is about to occur in the key detection area.

[0083] It can be understood that the pressure change curve of the non-key detection area can also be compared with the standard pressure change curve of the non-key detection area by the above comparison method, and whether the safety hazard occurs or is about to occur in the non-key detection area can be judged.

[0084] The safety hazard, the preset standard can be stored in the central control system, and the central control system is in communication connection with the BMS to obtain each pressure data and judge whether there is abnormal data; of course, the preset standard can also be stored in the BMS, and the BMS judges whether there is abnormal data in each pressure data according to the preset standard. The central control system can also be in communication connection with the controller to obtain the pressure data stored in the controller.

[0085] The preset standard can be obtained according to experiments, or can be obtained from a large number of real data in the use process of the battery cell, or can be obtained according to the experimental results combined with the real data of the battery cell in the use process.

[0086] As another implementation, the pressure distribution data of each non-key detection area and key detection area of the battery cell from normal charging and discharging state to occurrence of safety hazard can also be detected by the pressure detection unit under preset conditions, and a curve of the first surface expansion force of the battery cell changing with the electric quantity is drawn according to each pressure distribution data, and the curve is defined as a non-standard pressure change curve. The standard pressure change curve of each key detection area and non-key detection area on the first surface and the non-standard pressure change curve are taken as preset standards. As an implementation, the pressure change curve of the key detection area, the non-standard pressure change curve of the key detection area and the standard pressure change curve of the key detection area are compared to determine whether the key detection area occurs or is about to occur safety hazard. Under the same electric quantity change interval, the slope change of the pressure change curve, the slope change of the pressure curve under non-standard condition and the slope change of the pressure curve under standard condition are compared to determine whether the key detection area occurs or is about to occur safety hazard. The way of obtaining the standard curvature change curve and the real-time curvature change curve has been described above, and will not be specifically described here. It can be understood that the non-standard curvature change curve can be obtained by derivation of the non-standard pressure change curve. During detection, the pressure change curve of the key detection area is obtained, and the pressure change curve is derived to obtain the curvature change curve to be detected. Under the same charging and discharging state, the change trend of the curvature change curve to be detected is determined according to the standard curvature change curve and the non-standard curvature change curve, and if the change trend of the curvature change curve to be detected is similar to the change trend of the non-standard curvature change curve, it is determined that the key detection area occurs or is about to occur safety hazard.

[0087] Step 3: The central control system is in communication connection with the BMS to obtain the specific position of the non-key detection area when it is detected that the non-key detection area occurs or is about to occur safety hazard, and the position is newly set as a key detection area.

[0088] As can be seen from the above, the standard pressure change curve and / or non-standard pressure change curve of each key detection area and non-key detection area obtained in advance are taken as preset standards, the pressure distribution curve of the key detection area and the non-key detection area is compared with the preset standards, and whether the battery cell exists safety risk is determined, so that the battery safety condition is more objectively and accurately detected, and the reliability, practicality and safety are further improved. Through real-time analysis, processing and judgment of the key detection area, the present application can timely alarm when the battery cell occurs safety hazard, and through interval analysis, processing and judgment of the non-key detection area, the omission of the battery cell pressure detection can be avoided, and the whole surface of the battery cell can be ensured to be pressure detected.

[0089] Please refer to Figure 12The application further provides a vehicle, which comprises a driving device, a battery, and the battery intelligent safety detection device as described above.

[0090] The above is only optional embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for obtaining a critical detection area of an electric cell, characterized in that, The method comprises the following steps: obtaining pressure data of a first surface of a battery cell under preset conditions within one or several charging and discharging cycles; forming a pressure distribution map of the first surface; determining a key detection area according to the pressure distribution map; the pressure data is obtained by a pressure detection unit arranged on the first surface; the pressure detection unit comprises a thin film sensing sheet and a collector electrically connected to the thin film sensing sheet; the method for determining the key detection area according to the pressure distribution map comprises the following steps: dividing the thin film sensing sheet into several regions; calculating the total pressure of each region of the first surface within one or several charging and discharging cycles; determining whether the total pressure of each region exceeds a second threshold value, and if so, setting the region as the key detection area; the method further comprises the following steps: calculating the coefficient of variation of each region of the first surface which is not set as the key detection area; setting the region with a coefficient of variation exceeding a preset value as the key detection area; The formula for calculating the coefficient of variation is: wherein is the standard deviation of the pressure of the slice, is the average value of the pressure of the slice.

2. A method for obtaining a critical detection area of an electric cell, characterized in that, The method comprises the following steps: obtaining pressure data of a first surface of a battery cell under preset conditions within one or several charging and discharging cycles; forming a pressure distribution map of the first surface; determining a key detection area according to the pressure distribution map; the pressure data is obtained by a pressure detection unit arranged on the first surface; the pressure detection unit comprises a thin film sensing sheet and a collector electrically connected to the thin film sensing sheet; the method for determining the key detection area according to the pressure distribution map comprises the following steps: dividing the thin film sensing sheet into several regions; calculating the total pressure of the first surface at each time within one or several charging and discharging cycles; locating the time when the total pressure of the first surface is maximum; determining whether the real-time pressure of each region at the time exceeds a third threshold value, and if so, setting the region as the key detection area; the method further comprises the following steps: calculating the coefficient of variation of each region of the first surface which is not set as the key detection area; setting the region with a coefficient of variation exceeding a preset value as the key detection area; The formula for calculating the coefficient of variation is: wherein is the standard deviation of pressure for the slice, is the average pressure for the slice.

3. The method of claim 1 or 2, wherein, The first surface is defined by the following method: obtaining pressure data of each surface of a battery cell under preset conditions within one or several charging and discharging cycles; obtaining the maximum pressure value of each surface; defining the surface with the maximum median value of the maximum pressure value as the first surface; the pressure data is obtained by a pressure detection unit arranged on each surface of the battery cell.

4. The method of claim 1 or 2, wherein, The first surface is defined by the following method: obtaining pressure data of each surface of a battery cell under preset conditions within one or several charging and discharging cycles; obtaining the maximum pressure value of each surface; defining the surface with the maximum pressure value exceeding a first threshold value as the first surface; the pressure data is obtained by a pressure detection unit arranged on each surface of the battery cell.

5. The method of claim 1 or 2, wherein, The method further comprises the following steps: during the actual charging and discharging process of the battery cell, if it is determined that other regions except the key detection area have safety hazards, the regions are corrected as the key detection area.

6. The method of claim 5, wherein, The determination that the other regions have safety hazards comprises the following steps: if the total pressure of the region within any one charging cycle exceeds a fourth threshold value; or, if the average pressure value of the region within any one charging cycle exceeds a fifth threshold value.

7. The method of claim 1 or 2, wherein, The method for determining the key detection area according to the pressure distribution map comprises: selecting a key detection point according to the pressure distribution map, and setting a key detection area centered on the key detection point.

8. The method of claim 7, wherein, The method for selecting the key detection point according to the pressure distribution map is: The difference between the maximum pressure value and the minimum pressure value of each point on the first surface in one or several charge and discharge cycles is calculated respectively; It is judged whether the difference exceeds a sixth threshold value, and if so, the point is set as the key detection point.

9. The method of claim 7, wherein, The method for selecting the key detection point according to the pressure distribution map is: The average pressure value Fs of the entire first surface and the average pressure value Fp of each point on the first surface in one or several charge and discharge cycles are calculated respectively; The point where Fp is greater than Fs is set as the key detection point.

10. The method of claim 7, wherein, The key detection area centered on the key detection point is set, which comprises: setting the area within a preset diameter range with the key detection point as the center as the key detection area.

11. A battery intelligent safety detection method, characterized in that, It comprises: Obtaining the pressure data of the first surface of the battery cell detected by the pressure detection unit; Analyzing and processing the pressure data of the key detection area on the first surface; Judging whether the battery cell has a safety hazard according to a preset standard; The key detection area is obtained by the method of any one of claims 1 to 10.

12. The method of claim 11, wherein The preset standard comprises: a first standard pressure change curve of the key detection area; and the first standard pressure change curve is a curve of the expansion force of the key detection area varying with the electric quantity under the normal charge and discharge condition of the battery cell. The analyzing and processing of the pressure data of the key detection area on the first surface, and the judging whether the battery cell has a safety hazard according to the preset standard, specifically comprises: Drawing a first pressure change curve of the key detection area according to the pressure data; Comparing the slope change of the first pressure change curve with the slope change of the first standard pressure change curve, and judging whether the battery cell has a safety hazard according to the comparison result.

13. The method of claim 12, wherein, Comparing the slope change of the first pressure change curve with the slope change of the first standard pressure change curve stored in advance, and judging whether the key detection area has a safety hazard according to the comparison result; Specifically comprising: Comparing a value A1 corresponding to the first pressure change curve with a value A2 corresponding to the first standard pressure change curve under the same electric quantity; If the value A1 is greater than the value A2, and the difference between the values is greater than a seventh threshold value, it is judged that the battery cell has a safety hazard.

14. The method of claim 12, wherein, Comparing the slope change of the first pressure change curve with the slope change of the first standard pressure change curve stored in advance, and judging whether the key detection area has a safety hazard according to the comparison result; Specifically comprising: Deriving the first standard pressure change curve to obtain a first standard curvature change curve corresponding to the first standard pressure change curve, and deriving the first pressure change curve to obtain a first curvature change curve corresponding to the first pressure change curve; Comparing a value B1 corresponding to the first curvature change curve with a value B2 corresponding to the first standard curvature change curve under the same electric quantity; If the value B1 is greater than the value B2, and the difference between the values is greater than an eighth threshold value, it is determined that the battery cell has a safety hazard.

15. The method of claim 12, wherein, Further comprising: The preset standard further comprises: a first non-standard pressure change curve of the key detection area; the first non-standard pressure change curve is a curve of the expansion force of the key detection area of the battery cell varying with the electric quantity from the normal charging and discharging state to the occurrence of the safety hazard; The pressure data of the key detection area in the first surface is analyzed and processed, and it is determined whether the battery cell has a safety hazard according to the preset standard, and the method further comprises: The slope change of the first pressure change curve is compared with the slope change of the first non-standard pressure change curve, and it is determined whether the key detection area has a safety hazard according to the comparison result.

16. The method of claim 11, wherein, Further comprising: The pressure data of the non-key detection area in the first surface is analyzed and processed; The non-key detection area is other area outside the key detection area of the first surface.

17. The method of claim 16, wherein The preset standard further comprises: a second standard pressure change curve of the non-key detection area; the second standard pressure change curve is a curve of the expansion force of the non-key detection area varying with the electric quantity under the normal charging and discharging condition of the battery cell; The pressure data of the non-key detection area in the first surface is analyzed and processed, and it is determined whether the battery cell has a safety hazard according to the preset standard, and the method further comprises: A second pressure change curve of the non-key detection area is drawn according to the pressure data; The slope change of the second pressure change curve is compared with the slope change of the second standard pressure change curve stored in advance, and it is determined whether the battery cell has a safety hazard according to the comparison result.

18. The method of claim 17, wherein, Further comprising: The preset standard further comprises: a second non-standard pressure change curve of the non-key detection area; the second non-standard pressure change curve is a curve of the expansion force of the non-key detection area varying with the electric quantity from the normal charging and discharging state to the occurrence of the safety hazard; The pressure data of the non-key detection area in the first surface is analyzed and processed, and it is determined whether the battery cell has a safety hazard according to the preset standard, and the method further comprises: The slope change of the second pressure change curve is compared with the slope change of the second non-standard pressure change curve stored in advance, and it is determined whether the key detection area has a safety hazard according to the comparison result.

19. The method of claim 16, wherein, The pressure data of the key detection area in the first surface is analyzed and processed in real time, and the pressure data of the non-key detection area in the first surface is analyzed and processed at a preset sampling frequency.

20. A battery intelligent safety detection device, characterized in that, The pressure detection module comprises a controller and a plurality of pressure detection units, and the pressure detection unit comprises a thin film sensing sheet and a data collector; the input end of the data collector is electrically connected with the thin film sensing sheet, and the output end is in communication connection with the controller; the control module comprises a BMS in communication connection with the controller; the thin film sensing sheet is configured to change at least one electrical parameter when subjected to pressure, and the data collector is used to convert the electrical parameter data into pressure data and transmit the pressure data to the controller; The controller or the BMS is configured to implement the method for obtaining the key detection area of the battery cell according to any one of claims 1 to 10 and / or implement the intelligent safety detection method of the battery according to any one of claims 11 to 19.

21. The battery intelligent safety detection apparatus of claim 20, wherein, The battery comprises at least two groups of battery modules, each group of battery modules comprising at least one battery cell; the data collectors in the pressure detection units are connected in parallel and electrically connected to the controller; or the data collectors in the pressure detection units are respectively electrically connected to the controller.

22. A vehicle characterized by The battery comprises a driving device, a battery, and the intelligent safety detection device of the battery according to claim 20 or 21.

23. A battery intelligent safety detection system, characterized in that, The battery comprises a central control system and a plurality of intelligent safety detection devices of the battery; the intelligent safety detection device of the battery comprises a pressure detection module and a control module, the pressure detection module comprises a controller and a plurality of pressure detection units corresponding to the battery modules, each pressure detection unit comprises a thin film sensing sheet and a data collector; the input end of the data collector is electrically connected to the thin film sensing sheet, and the output end is communicatively connected to the controller; the control module comprises a BMS communicatively connected to the controller; the thin film sensing sheet is configured to change at least one electrical parameter when subjected to pressure; the data collector is configured to convert the electrical parameter data into pressure data and transmit the pressure data to the controller; the central control system is communicatively connected to the BMS. The central control system is configured to implement the method for obtaining the key detection area of the battery cell according to any one of claims 1 to 10 and / or implement the intelligent safety detection method of the battery according to any one of claims 11 to 19.

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