CN114734874A

CN114734874A - Method for acquiring key detection area of battery core, intelligent safety detection method, device and system of battery and vehicle

Info

Publication number: CN114734874A
Application number: CN202210480893.9A
Authority: CN
Inventors: 叶宏; 汪晓阳; 陈旭; 杨坤
Original assignee: Tai Shen Technology Shenzhen Co ltd
Current assignee: Tai Shen Technology Shenzhen Co ltd
Priority date: 2022-05-05
Filing date: 2022-05-05
Publication date: 2022-07-12

Abstract

The application discloses a method for obtaining a key detection area of an electric core, which comprises the steps of forming a pressure distribution diagram of a first surface of the electric core by obtaining pressure data of the first surface of the electric core in one or a plurality of charging and discharging periods under a preset condition, and determining the key detection area according to the pressure distribution diagram. The invention further discloses an intelligent safety detection method for the battery, which comprises the steps of acquiring pressure data of the first surface of the battery cell in the battery assembly, detected by the pressure detection unit, analyzing and processing the pressure data of a key detection area in the first surface, and judging whether the battery cell has potential safety hazards or not according to a preset standard. The invention further discloses an intelligent safety detection device and system for the battery and a vehicle. The invention can improve the accuracy of the safety detection of the battery and realize the early warning of the health problem of the battery.

Description

Method for acquiring key detection area of battery core, intelligent safety detection method, device and system of battery and vehicle

Technical Field

The application belongs to the field of battery detection, and particularly relates to a method for acquiring a key detection area of a battery core, an intelligent battery safety detection method, an intelligent battery safety detection device, an intelligent battery safety detection system and a vehicle.

Background

With the integration of the new energy automobile into the tide, the traditional automobile factories are also accelerated to arrange in the direction of new energy. At present, a common new energy automobile usually adopts a rechargeable battery to provide power, however, spontaneous combustion explosion accidents caused by the fact that the battery is connected with three batteries are caused, the problems of safety and stability of the new energy automobile battery are pushed to an air outlet of public opinion, the internal pain is caused, and the safety problem is paid more and more attention by many people. At present, the management and detection of common power batteries generally focus on the detection of temperature, voltage, current, chemical gas and other dimensions, and the operation state of the power battery is comprehensively monitored and managed. However, the safety monitoring performed from these dimensions is still insufficient, and the potential safety hazard cannot be discovered in time.

At present, a single-point or multi-point pressure sensor is usually arranged on a battery, and the expansion condition of the battery is detected by the single-point or multi-point pressure sensor, but because the working condition of the battery is complex in the actual working process, the place where the expansion deformation occurs is not necessarily the place estimated in advance, and therefore, the phenomenon of missing detection or inaccurate detection result often exists when the single-point or multi-point pressure sensor is used for detecting the expansion condition of the battery.

Disclosure of Invention

The application aims to provide a method for acquiring a key detection area of a battery core, a battery intelligent safety detection method, a device, a system and a vehicle, so as to improve the accuracy of battery safety detection and realize early warning of battery health problems.

The technical scheme of the application mainly comprises the following aspects:

a first aspect of the present application provides a method for acquiring a cell focus detection area, which mainly includes: acquiring pressure data of the first surface of the battery cell in one or a plurality of charge-discharge cycles under a preset condition; forming a pressure profile of the first surface; determining a key detection area according to the pressure distribution diagram; the pressure data is obtained by detecting a pressure detection unit arranged on the first surface; the pressure detection unit comprises a film sensing sheet and a collector electrically connected with the film sensing sheet.

Further, the application also discloses an optional first surface definition mode; the manner in which the key detection regions are determined, etc.

A second aspect of the present application provides an intelligent battery safety detection method, which mainly includes: acquiring pressure data of a first surface of a battery cell in a battery pack, which is 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 potential safety hazards or not according to a preset standard; wherein the focus detection area is obtained by the method of the first aspect or any alternative.

Further, the application also discloses an optional setting mode of the preset standard, a mode of judging whether potential safety hazards exist in the battery cell based on the preset standard and the like.

The third aspect of the application provides an intelligent safety detection device for a battery, which mainly comprises a pressure detection module and a control module, wherein the pressure detection module comprises a controller and pressure detection units, the number of the pressure detection units is not less than that of battery modules, and each pressure detection unit is provided with a film sensing sheet and a data acquisition unit; the input end of the data acquisition unit is electrically connected with the film sensing sheet, the output end of the data acquisition unit is in communication connection with the controller, and the control module comprises a BMS (battery management system) in communication connection with the controller; the film sensing chip is configured to change at least one electrical parameter when being pressed, and the data collector is used for converting the electrical parameter data into pressure data and transmitting the pressure data to the controller; the controller or the BMS is configured to implement the method for acquiring a cell emphasis detection area according to the first aspect of the present application or any one of the alternatives thereof and/or is configured to implement the battery intelligent safety detection method according to the second aspect of the present application or any one of the alternatives thereof.

A fourth aspect of the present application provides a vehicle, which mainly comprises a driving device, a battery and the battery intelligent safety detection device of the third aspect.

A fifth aspect of the present application provides an intelligent battery safety detection system, which mainly includes a central control system and a plurality of intelligent battery safety detection devices; the intelligent safety detection device for the battery comprises a pressure detection module and a control module, wherein the pressure detection module comprises a controller and pressure detection units, the number of the pressure detection units is not less than that of battery modules, and each pressure detection unit is provided with a film sensing piece and a data acquisition unit; the input end of the data acquisition unit is electrically connected with the film sensing sheet, the output end of the data acquisition unit is in communication connection with the controller, and the control module comprises a BMS in communication connection with the controller; the film sensing chip is configured to change at least one electrical parameter when being pressed, and the data collector is used for converting the electrical parameter data into pressure data and transmitting the pressure data to the controller; the central control system is in communication connection with the BMS; the central control system is used for realizing the method for acquiring the battery core key detection area in the first aspect of the application or any one of the alternatives thereof and/or is used for realizing the intelligent battery safety detection method in the second aspect of the application or any one of the alternatives thereof.

The application has the following beneficial effects:

1. in the present invention, since the thin-film sensor chip can cover the entire surface area of the first surface of the cell, pressure data of the entire surface of the first surface can be obtained by the thin-film sensor chip. Can acquire electric core when charge-discharge through pressure detection unit, the biggest expansibility of first surface to can fix a position the position that this biggest expansibility appears on the first surface, combine the charge-discharge data of electric core simultaneously, according to the electric quantity condition of electric core, can also fix a position when the biggest expansibility appears in the first surface. In the prior art, the pressure distribution of a certain surface cannot be obtained through single-point detection, and even if a plurality of points are arranged on a certain surface, the accurate surface pressure distribution and surface average pressure cannot be obtained, so that a surface which is easy to expand cannot be obtained, and the position of the maximum expansion force on the certain surface cannot be accurately obtained. In the invention, the outer surface of the battery cell is completely covered by the film type pressure sensor, the pressure change of each surface of the battery cell is detected, and the surface of the battery cell, which is easy to generate the expansion risk, is objectively and accurately positioned. Through carrying out the detection analysis of whole face to this face, can also be through the pressure distribution map that generates audio-visual, accurate key check point or key check region of acquireing, the user identification of being convenient for has also avoided the erroneous judgement that manual work discerned key check region and lead to.

2. It will be appreciated that the expansion of the cell is not only at one point, but also in a region, and that there is a risk of damage in regions with severe expansion. If only the pressure at a certain point exceeds the set threshold, the regions which do not exceed the set threshold are easy to be omitted, but the regions are easy to be damaged, which may lead to inaccurate detection results. The detection mode covering the first surface overcomes the defect of taking points as detection objects, can more accurately and effectively detect key detection areas needing attention of the first surface, and meanwhile, can avoid the defect of omission of the key detection areas by calculating the CV values of all the areas.

3. The intelligent safety detection device for the battery detects the pressure of the whole battery cell, avoids the omission problem of single-point detection or multi-point detection, further improves the reliability of a detection result, and also improves the safety of the battery in the use process.

4. Battery intelligent safety detection device is through setting up a pressure detection unit on each battery module at least, and each pressure detection unit can carry out the bulging force to the electric core in each battery module of department and detect, and then realizes the comprehensive cover that detects the battery pack bulging force, and each data collection station all is connected with BMS communication simultaneously, can realize carrying out real-time analysis and detection, convenient high efficiency to the bulging force condition of electric core in each battery module of department through a BMS system.

5. The invention can monitor the pressure data of the key detection area in real time according to the requirement, monitor the non-key detection area according to the preset frequency, correct the key detection area by combining the actual detection result and bring the new expansion risk point into the key detection area.

6. According to the invention, based on the pre-obtained standard pressure change curve chart and non-standard pressure change curve chart of each key detection area and non-key detection area as the preset standard, the pressure distribution curves of the key detection area and the non-key detection area are compared with the preset standard, so that whether the expansion risk exists in the battery cell is judged, and the safety condition of the battery is detected more objectively and accurately. Moreover, through comparison of curves, whether potential safety hazards of the battery are about to occur or not can be judged in advance, and reliability, practicability and safety are further improved.

7. The central control system can be in communication connection with the intelligent battery safety detection devices at the same time, acquires the cell pressure data detected by the intelligent battery safety detection devices, and corrects the key detection area of the battery cell by combining the cell pressure data and the method for acquiring the key detection area of the battery cell, so that the reliability and the accuracy of the battery safety detection are further improved.

Drawings

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 described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view of a battery pack;

FIG. 2 is a block diagram of an exemplary embodiment of an expansion force detection system;

fig. 3 is a schematic structural diagram of a pressure detection unit provided in an embodiment of the present application;

fig. 4 is a schematic diagram illustrating a connection manner between the BMS, the controller, and the data collector according to an embodiment of the present disclosure;

fig. 5 is a schematic installation diagram of a pressure detection unit provided in an embodiment of the present application;

fig. 6 is a schematic flow chart of a method for acquiring a cell key detection area according to the embodiment of the present application;

fig. 7 is a schematic view illustrating the installation of a thin film sensor chip according to an embodiment of the present application;

fig. 8 is a first schematic diagram illustrating a key detection area division provided in the embodiment of the present application;

fig. 9 is a schematic diagram illustrating a second key detection area division provided in the embodiment of the present application;

fig. 10 is a schematic diagram of a correction performed on a gravity detection area according to an embodiment of the present application;

fig. 11 is a schematic flowchart of a battery intelligent security detection method according to an embodiment of the present application;

FIG. 12 is a block schematic diagram of a vehicle provided in an embodiment of the present application;

the attached drawings are marked as follows: 11-film sensing chip, 12-data collector, 13-battery core and 14-shell.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It will be understood that when an element is referred to as being "disposed" or "disposed" on another element, it can be directly on the other element or be 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 be indirectly connected to the other element.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise. The meaning of "a number" is one or more unless specifically limited otherwise.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Referring to fig. 1, a battery assembly is first described, in which the battery assembly is formed by stacking one or more battery modules, and each battery module includes at least one battery cell. The intelligent safety detection device for the battery at least comprises an expansion force monitoring system, wherein the expansion force monitoring system is used for monitoring the expansion force change condition of the battery cell in the battery pack in real time and giving an alarm when the expansion force change of the battery cell is abnormal. Of course, the intelligent safety detection device for the battery can also comprise a temperature detection system for detecting the temperature of the battery, a gas concentration detection system for detecting whether electrolyte leaks in the battery, and the like.

Referring to fig. 2 and 3, in particular, the expansion force monitoring system is composed of a pressure detection module and a control module. Wherein, the control module mainly comprises a BMS (Battery MANAGEMENT SYSTEM ); the pressure detection module mainly comprises 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 condition of the battery core in the battery module, and the controller is in communication connection with the pressure detection unit to obtain a detection result through the pressure detection unit. As an embodiment, the controller may directly transmit the acquired detection result to the BMS, and the BMS may analyze the detection result; as another embodiment, the detection result is analyzed by the controller and transmitted to the BMS system.

The Controller and the BMS and the data collector CAN be connected by a Controller Area Network (CAN), and CAN be connected by other means such as a 485 bus interface.

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

In the invention, the pressure detection units can be arranged in one group or multiple groups, and the multiple groups of pressure detection units can be arranged in a battery module to respectively detect the expansion force change conditions of different battery cores in the battery module; the multiple groups of pressure detection units can also be respectively arranged in different battery modules to respectively detect the expansion force change conditions of the battery cores in different battery modules. As an implementation mode, when the battery pack is formed by superposing 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 respectively arranged in different battery modules so as to detect the expansion force change conditions of the battery cores in the different battery modules. In the present invention, as an implementation manner, the number of the pressure detection units is not less than the number of the battery modules, so that at least one pressure detection unit is disposed on each battery module, thereby enabling pressure detection of all the battery modules.

It can be understood that, when a plurality of groups of pressure detecting units are provided, the controller may obtain the detecting results of the plurality of groups of pressure detecting units simultaneously, or may obtain the detecting results of the plurality of groups of pressure detecting units respectively and sequentially. Referring to fig. 4 a, as an embodiment, the data collectors of the multiple sets of pressure detecting units are electrically connected to the controller after being connected in parallel through the data transmission lines, and the controller obtains the pressure data of each data collector. Referring to fig. 4B, as another embodiment, the data collectors of the multiple sets of pressure detecting units are electrically connected to the controller through data transmission lines, so that the controller can simultaneously or separately obtain the pressure data of each data collector.

It can be understood, through set up a pressure detection unit on each battery module at least, each pressure detection unit can carry out the bulging force to the electric core in each battery module, and then realize the comprehensive cover that detects the battery pack bulging force, each data collection station all is connected with controller communication simultaneously, combine BMS through the controller and can realize carrying out real-time analysis and detection to the bulging force condition of electric core in each battery module, when the BMS system analysis goes out battery module and has the potential safety hazard, the BMS system sends out the police dispatch newspaper, so that the testing process is more convenient high-efficient.

Furthermore, because each pressure detection unit is arranged in different battery modules, each data collector corresponds to different battery cores, and different digital numbers can be set for different data collectors so as to realize the one-to-one correspondence relationship between the data collectors and the battery cores. Like this, when BMS or controller detected to have the unusual electric core of inflation, can acquire the data collection station who provides corresponding data through BMS or controller to the electric core that can pinpoint the trouble through data collection station's digit serial number has higher practicality and time efficiency.

It can be understood that a group of pressure detection units may be disposed in any battery module, or multiple groups of pressure detection units may be disposed in any battery module. The film sensing chip of the pressure detection unit can be clamped between the two battery cells, and also can be clamped between the battery cells and a shell for mounting the battery cells.

Referring to fig. 5, as an embodiment, three sets of pressure detecting units are disposed in the battery module, and the three sets of pressure detecting units are disposed at two opposite ends and a middle position of the battery module, respectively. In this embodiment, the thin film sensing sheet covers a surface of the battery core, which is prone to swelling.

It can be understood that, when the inflation situation of change of electric core among the battery pack is monitored in real time through battery intelligent security detection device, each data collection station acquires the pressure data that corresponds electric core through the corresponding film sense piece, and each data collection station transmits the pressure data who detects to the controller, and the controller can be with each pressure data transmission to BMS in order to carry out the analysis and judge the health condition of each electric core in order to make effectual reply processing to each pressure data through BMS. Of course, the controller may also collect and analyze the pressure data, and transmit the analysis result to the BMS to determine the health condition of each cell through the BMS to make an effective coping process. Promptly, can carry out timely early warning to the problem that relates to electric core potential safety hazard through above-mentioned mode.

Referring to fig. 6, the present invention further provides a method for obtaining a cell key detection area, which mainly includes:

and A1, detecting the expansion force of each surface of the battery cell during charging and discharging through a pressure detection unit under a preset condition, and determining at least one surface (defining the surface as a first surface) of the battery cell, which is easy to expand, according to the detection result.

As shown in fig. 7, during detection, a plurality of film sensor sheets are attached to 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 by each film sensor sheet.

As an embodiment, the method for determining a surface susceptible to swelling may be: acquiring the maximum pressure value of each surface of the battery cell in one or more charge-discharge cycles of the battery cell, wherein the maximum value is the surface which is easy to expand; in another embodiment, the maximum pressure value of each surface of the battery cell is obtained in one or more charging and discharging cycles of the battery cell, and the surface with the maximum pressure value exceeding the set threshold value is set as the surface which is easy to expand.

The preset conditions may include an ambient temperature of the battery cell, an initial pressure applied to the battery cell, a mounting fixture of the battery cell to be tested, and the like. The preset conditions are set to simulate the real use scene of the battery cell during use, for example, the preset conditions may be set as: at an ambient temperature of 40 ℃, a certain initial pressure is applied to the battery cell to be detected through the tool clamp, the battery cell is charged and discharged under the condition, and the expansion force of each surface of the battery cell during charging and discharging is detected through the pressure detection unit.

And A2, detecting pressure data of the first surface of the battery cell during charging and discharging through the pressure detection unit under preset conditions to form a pressure distribution diagram (shown in figure 8) of the first surface, and determining a key detection area and/or a key detection point according to the pressure distribution diagram.

It is understood that since the thin-film sense sheet can cover the entire area of the first surface, pressure data of the entire area on the first surface can be obtained by the thin-film sense 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, the position of the maximum expansion force on the first surface can be located, and meanwhile, the maximum expansion force of the first surface can be located when the first surface occurs according to the electric quantity condition of the battery cell and the charging and discharging data of the battery cell. In the prior art, the pressure distribution condition of a certain surface cannot be obtained through single-point detection, and even if a plurality of points are arranged on the certain surface, the accurate surface pressure distribution condition and the surface average pressure condition cannot be obtained, so that the surface which is easy to expand cannot be obtained, and the position where the maximum expansion force appears on the certain surface cannot be accurately obtained. In the invention, the outer surface of the battery cell is completely covered by the film type pressure sensor, the pressure change of each surface of the battery cell is detected, and the surface of the battery cell, which is easy to generate the expansion risk, is objectively and accurately positioned. Further, through carrying out detection and analysis on the whole surface of the surface, key detection points or key detection areas can be visually and accurately obtained through the generated pressure distribution diagram, and the maximum expansive force can be positioned when the key detection points or the key detection areas on the first surface appear according to the electric quantity condition of the battery cell and the charging and discharging data of the battery cell, so that the user identification is facilitated, and the misjudgment caused by manually identifying the key detection areas is also avoided.

The method for judging the key detection point is obtained based on pressure data of the whole first surface, and one of the methods may be: and in one or a plurality of charge-discharge cycles of the battery cell, monitoring the pressure condition of the whole surface of the first surface in real time, judging whether the difference value between the maximum pressure value and the minimum pressure value of each point in the first surface exceeds a set threshold value, and if so, taking the point as a key detection point. The threshold value may be set according to a pressure applied to the cell casing when the cell casing is elastically deformed to the maximum extent, and is usually smaller than the pressure value. The maximum elastic deformation is usually related to the material, thickness, structure, etc., and can be calculated or obtained through experiments. The method for judging the key detection points can also comprise the following steps: and in one or a plurality of charge-discharge cycles of the battery cell, calculating the average pressure value of the whole surface of the first surface and the average pressure value of each point, and then taking the point of the first surface, the average pressure of which exceeds the average pressure value of the whole surface, as a key detection point.

The method for judging the key detection area may be as follows: and acquiring key detection points based on the mode, and dividing the area in a certain range into key detection areas by taking the key detection points as centers. The division of the area size can be set according to the size of the battery cell shell; or dividing the area within a certain diameter range into key detection areas by taking the key detection points as circle centers; and the key detection areas can be automatically divided according to the distribution condition of each key detection point.

Referring to fig. 9, in other embodiments, the key detection area may be directly obtained without obtaining the key monitoring point. The method for judging the key detection area can be as follows: firstly, the film sensor chip is divided into different areas, for example, the film sensor chip is divided into M × N equally divided areas (where M and N may be the same or different positive integers), pressure data of each area is obtained, the sum of pressures of each area (i.e., the total pressure of each area) in one or more charge-discharge cycles of the battery cell is respectively calculated, then whether the total pressure of each area exceeds a set pressure threshold is respectively judged, and if the total pressure of each area exceeds the set pressure threshold, the area is determined as a key detection area. Or, in one or more charge and discharge cycles of the battery cell, total pressure at each time of the first surface may be calculated, a time at which the total pressure of the first surface is maximum is located, whether real-time pressure of each segment at the time exceeds a set pressure threshold is obtained and judged, and if the real-time pressure exceeds the set pressure threshold, the segment is judged as a key detection area. The present invention is not particularly limited in the manner of determining the key area.

It is contemplated that some zones may not have a total pressure exceeding a set pressure threshold, but that the pressure change in the zone may fluctuate significantly, such that there are regions of greater pressure and regions of lesser pressure. In order to avoid missing a region with a large pressure, after the above steps, the CV value (coefficient of variation) is calculated for a segment whose total pressure does not exceed the set pressure threshold, and when the CV value of a certain segment exceeds the set value, the segment is also determined as the key detection region. By means of the method, the accuracy of dividing the key detection area can be further improved, and omission of the key detection area is avoided.

In the invention, the CV value calculation formula of each patch is as follows:

wherein SD is the standard deviation of the pressure of the area, and the calculation formula of SD is as follows:

in the formula, X_iRepresents the pressure value of the ith sample in the area, i is 1, 2.

Represents the average pressure value of the N samples in the area; n is the number of samples taken.

Wherein, MN is the average pressure value of this district, and MN computational formula is:

in the formula, X_iIndicating the pressure value of the ith sample in the area, and N is the number of samples adopted.

It is understood that, in the present invention, the total pressure in the region is used as a criterion because the cell is not expanded at a certain point, but a certain region is expanded, and the region with serious expansion is damaged. If only the pressure at a certain point exceeds the set threshold, the regions that do not exceed the set threshold are likely to be omitted, but these regions are likely to be damaged, which may lead to inaccurate detection results. The detection method of the invention divides the first surface into different areas, takes the areas as the monitoring objects, takes the total pressure in the areas as the judgment standard, detects the whole area of the first surface, overcomes the defect of taking points as the detection objects by covering the first surface, can more accurately and effectively detect the key detection area of the first surface which needs to be concerned, and simultaneously can avoid the defect of omission of the key detection area by calculating the CV value of each area. It is to be understood that other areas outside the first surface area of emphasized detection may be defined as non-emphasized detection areas.

Referring to fig. 10, as an improvement, while the key detection area of the battery cell in the use process of the battery cell is determined by the above method, the key detection area of the battery cell in the experimental detection may be corrected according to the collected pressure detection data of the battery cell in the actual use process. For example, by analyzing the pressure detection data of the battery cell in the actual operation process, it is found that the average pressure value of the non-key detection area divided by the experiment in the actual operation process of the battery cell exceeds the set threshold, and the area should be modified into the key detection area. As an embodiment, by analyzing pressure detection data in a certain charge-discharge cycle during the actual operation of the battery cell, if the total pressure value of a non-emphasis detection region exceeds a threshold value, the non-emphasis detection region is modified into an emphasis detection region. As another embodiment, by analyzing the pressure detection data in a plurality of charge and discharge cycles in the actual operation process of the battery cell, if the total pressure value of a non-important detection area exceeds a threshold value in each charge and discharge cycle, the non-important detection area is modified into an important detection area.

It can be understood that the real service condition of the battery is complex, the factors influencing the expansion of the battery are more, the pressure detection data of the battery cell in the actual application process are analyzed to correct the key detection area, and the key detection area which is ensured to be obtained is more accurate.

The invention also provides an intelligent battery safety detection system which comprises the intelligent battery safety detection device and a central control system, wherein the central control system can be in communication connection with the intelligent battery safety detection devices at the same time. The cell pressure data detected by the intelligent battery safety detection device can be acquired through the central control system, and meanwhile, the central control system can analyze and correct key detection areas of the battery cell according to the cell pressure data by combining the method for acquiring the key detection areas of the battery cell.

Referring to fig. 11, the present invention further provides an intelligent battery safety detection method, which performs real-time monitoring on the expansion force variation condition of a battery cell in a battery assembly through an intelligent battery safety detection apparatus, and the method mainly includes:

step 1: pressure data on the corresponding battery cell are acquired through each pressure detection unit, the detected pressure data result is transmitted to the controller, and the controller analyzes and processes the pressure data of the important detection area or the important detection area and the non-important detection area.

It should be noted that, in the present invention, the key detection area of the battery cell is an area in which the battery cell is likely to swell during use, and the non-key detection area is an area outside the key detection area on the surface of the battery cell. The key detection area of the battery cell can be obtained through experiments according to the embodiment, can also be obtained through a large amount of real data in the use process of the battery cell, and can also be obtained through combining the real data of the battery cell in the use process according to the experiment result.

As an implementation manner, each pressure detection unit acquires pressure data on a corresponding battery cell in real time, and the controller performs real-time analysis on the pressure data of a key detection area and draws a pressure change curve of the key detection area. As another embodiment, each pressure detection unit may acquire pressure data on a corresponding battery cell according to a preset frequency, and the controller analyzes the pressure data of the key detection area after acquiring the pressure data, and draws a pressure change curve of the key detection area. The pressure change curve graph reflects the trend that the expansion force of each area on the surface of the battery cell changes along with the electric quantity of the battery cell in a normal charging and discharging state.

In other embodiments, the controller may further analyze the pressure data of the non-emphasized detection region at a preset frequency, and draw a pressure variation graph of the non-emphasized detection region. The preset frequency can be set by a user, as an implementation mode, the controller can be set to analyze the non-key detection area every 20 minutes, and data of 40 minutes are acquired by one-time analysis; the non-emphasized detection region may be analyzed every 10 minutes, and data may be acquired for 40 minutes for one analysis. Of course, when each pressure detection unit collects the pressure data on the corresponding cell in real time, the controller may also analyze the pressure data of the non-emphasized detection area in real time and draw a pressure change curve of the non-emphasized detection area. The data detection frequency of the emphasized or non-emphasized detection region is not particularly limited in the present invention.

Step 2: and judging whether abnormal data exist in the pressure data according to a preset standard.

Specifically, the method for judging whether abnormal data exist in each pressure data according to the preset standard comprises the following steps:

and comparing the pressure change curve chart of the key detection area with the standard pressure change curve chart of the key detection area to judge whether the key detection area has potential safety hazards or is about to have the potential safety hazards.

As an implementation manner, 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 potential safety hazard occurs or is about to occur in the key detection area is judged according to the comparison result. Specifically, under the condition that the battery cell is normally charged and discharged, the change condition of the expansion force of a key detection area and a non-key detection area of the battery cell in one or more charging and discharging periods can be obtained through pressure detection on the surface of the battery cell, a change curve graph of the expansion force along with the electric quantity is obtained, the graph is defined as a standard pressure change curve graph, a derivation is carried out on the standard pressure change curve, and a standard curvature change curve of the standard pressure change curve can be obtained. During detection, a pressure change curve of the key detection area is obtained, and derivation is carried out on the pressure change curve to obtain a curvature change curve to be detected of the key detection area. And in the same electric quantity change interval, comparing a numerical value corresponding to a standard curvature change curve of the key detection area with a numerical value corresponding to a curvature change curve to be detected, and judging that the potential safety hazard occurs or is about to occur in the key detection area when the numerical value corresponding to the curvature change curve is greater than the numerical value corresponding to the standard curvature change curve and the difference value between the numerical value corresponding to the curvature change curve and the numerical value corresponding to the standard curvature change curve is greater than a set threshold value.

As another embodiment, in the same electric quantity change interval, comparing a value corresponding to a pressure change curve of the key detection area with a value corresponding to a standard pressure change curve of the key detection area, and when the value corresponding to the pressure change curve is greater than the value corresponding to the standard pressure change curve and a 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, determining that the key detection area is or is about to have a potential safety hazard.

It can be understood that, by the above comparison method, the pressure change curve graph of the non-emphasis detection region can be compared with the standard pressure change curve graph of the non-emphasis detection region, and whether a potential safety hazard occurs or is about to occur in the non-emphasis detection region can be determined.

The system comprises a central control system, a BMS and a safety hazard, wherein the preset standard can be stored in the central control system, the central control system is in communication connection with the BMS to acquire each pressure data, and whether abnormal data exist or not is judged; of course, the preset standard can also be stored in the BMS, and the BMS judges whether abnormal data exist in each pressure data according to the preset standard. The central control system can also be in communication with the controller to obtain pressure data stored in the controller.

The preset standard can be obtained through experiments, can also be obtained through a large amount of real data in the using process of the battery cell, and can also be obtained through combining the real data of the battery cell in the using process according to the experimental result.

As another embodiment, the pressure distribution data of each non-key detection area and each key detection area when the electric core is in a normal charging and discharging state and potential safety hazard occurs may also be detected by the pressure detection unit under a preset condition, and a curve of the first surface expansion force of the electric core changing along with the electric quantity is drawn according to each pressure distribution data, and the curve is defined as a non-standard pressure change curve. And taking the standard pressure change curve graph and the non-standard pressure change curve graph of each key detection area and each non-key detection area on the first surface as preset standards. In one embodiment, 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 has or is about to have a potential safety hazard. And under the same electric quantity change interval, comparing the slope change of the pressure change curve, the slope change of the pressure curve under the non-standard condition and the slope change of the pressure curve under the standard condition, and judging whether the key detection area has potential safety hazards or is about to have the potential safety hazards according to the comparison result. The manner of obtaining the standard curvature variation curve and the real-time curvature variation curve is explained above, and will not be described in detail here. It will be appreciated that a non-standard curvature profile can be obtained by taking the derivative of a non-standard pressure profile. During detection, a pressure change curve of a key detection area is obtained, and the pressure change curve is derived to obtain a curvature change curve to be detected. And under the same charging and discharging state, judging the change trend of the curvature change curve to be detected 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, judging that the potential safety hazard occurs or is about to occur in a key detection area.

And step 3: the central control system is in communication connection with the BMS so as to acquire the specific position of the non-key detection area when the potential safety hazard of the non-key detection area is detected to occur or is about to occur, and the position is newly set as the key detection area.

In summary, the invention compares the pressure distribution curves of the key detection areas and the non-key detection areas with the preset standard based on the pre-obtained standard pressure change curve graphs and/or non-standard pressure change curve graphs of the key detection areas and the non-key detection areas as the preset standard, thereby determining whether the battery cell has a safety risk, detecting the safety condition of the battery more objectively and accurately, and further improving the reliability, the practicability and the safety. According to the invention, through real-time analysis, processing and judgment of the key detection areas, early warning can be timely carried out when potential safety hazards occur in the battery cell, and through interval analysis, processing and judgment of the non-key detection areas, omission of battery cell pressure detection can be avoided, and pressure detection of the whole surface of the battery cell can be ensured.

Referring to fig. 12, the present invention further provides a vehicle, which includes a driving device, a battery and the above-mentioned battery intelligent safety detection device, where the battery provides energy for the driving device, and the battery intelligent safety detection device is used to perform safety detection on the battery and send an alarm when a potential safety hazard occurs in the battery.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.

Claims

1. A method for obtaining a cell key detection area is characterized by comprising the following steps:

acquiring pressure data of the first surface of the battery cell in one or a plurality of charge-discharge cycles under a preset condition;

forming a pressure profile of the first surface;

determining a key detection area according to the pressure distribution diagram;

the pressure data is obtained by detecting a pressure detection unit arranged on the first surface; the pressure detection unit comprises a film sensing sheet and a collector electrically connected with the film sensing sheet.

2. The method of claim 1, wherein the first surface is defined by:

acquiring pressure data of each surface of the battery cell in one or a plurality of charge-discharge periods under a preset condition;

obtaining the maximum pressure value of each surface;

defining the surface with the largest median value of the maximum pressure values as a first surface;

the pressure data are obtained by detecting pressure detection units arranged on the surfaces of the battery cell.

3. The method of claim 1, wherein the first surface is defined by:

obtaining the maximum pressure value of each surface;

defining a surface for which the maximum pressure value exceeds a first threshold value as a first surface;

4. The method of claim 1, wherein determining the focus detection zone from the pressure profile comprises:

equally dividing the thin film sensor chip into a plurality of areas;

respectively calculating the total pressure of each area of the first surface in one or a plurality of charge-discharge periods;

and respectively judging whether the total pressure of each section exceeds a second threshold value, and if so, setting the section as a key detection area.

5. The method of claim 1, wherein determining the focus detection zone from the pressure profile comprises:

equally dividing the thin film sensor chip into a plurality of areas;

respectively calculating the total pressure of the first surface at each moment in one or a plurality of charge-discharge periods;

locating a moment when the total pressure of the first surface is maximum;

and respectively judging whether the real-time pressure of each subarea at the moment exceeds a third threshold value, and if so, setting the subarea as a key detection area.

6. The method of claim 4 or 5, further comprising:

calculating the variation coefficient of other areas of the first surface which are not set as the key detection areas;

setting the section with the coefficient of variation exceeding a preset value as a key detection area;

the calculation formula of the coefficient of variation is as follows:

where SD is the standard deviation of the pressure of the patch and MN is the average of the pressure of the patch.

7. The method of claim 4 or 5, further comprising: and in the actual charging and discharging process of the battery cell, if the potential safety hazard exists in other areas except the key detection area, correcting the areas into the key detection area.

8. The method of claim 7, wherein the determination that the other tiles have a potential safety hazard comprises:

if the total pressure of the area in any charging period exceeds a fourth threshold value; alternatively, the average pressure value of the patch during any one charging cycle exceeds a fifth threshold value.

9. The method of claim 1, wherein determining the focus detection zone from the pressure profile comprises: firstly, selecting a key detection point according to the pressure distribution diagram, and then setting a key detection area by taking the key detection point as a center.

10. The method of claim 9, wherein the selected focus detection points are selected from the pressure profile by:

respectively calculating the difference value between the maximum pressure value and the minimum pressure value of each point in the first surface in one or a plurality of charge-discharge periods;

and judging whether the difference value exceeds a sixth threshold value, and if so, setting the point as a key detection point.

11. The method of claim 9, wherein the selected focus detection points are selected from the pressure profile by:

respectively calculating the average pressure value Fs of the whole first surface and the average pressure value Fp of each point in the first surface in one or a plurality of charge-discharge periods;

points where Fp is greater than Fs are set as emphasized detection points.

12. The method of claim 9, wherein setting the focus detection point as a focus detection area includes: setting the area within the preset diameter range as a key detection area by taking the key detection point as the circle center.

13. An intelligent battery safety detection method is characterized by comprising the following steps:

acquiring pressure data of a first surface of a battery cell in a battery pack, which is 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 potential safety hazards or not according to a preset standard;

the focus detection zone is obtained by the method of any one of claims 1 to 12.

14. The method of claim 13,

the preset criteria include: a first standard pressure change curve of a key detection area; the first standard pressure change curve is a curve of the expansion force of a key detection area along with the change of electric quantity under the condition of normal charge and discharge of the battery cell;

analyzing and processing pressure data of a key detection area in the first surface, and judging whether potential safety hazards exist in the battery cell according to preset standards, wherein the method specifically comprises the following steps:

drawing a first pressure change curve graph of a key detection area according to the pressure data;

and comparing the slope change of the first pressure change curve with the slope change of a first standard pressure change curve, and judging whether the potential safety hazard exists in the battery cell according to a comparison result.

15. The method of claim 14, wherein the slope change of the first pressure change curve is compared with a slope change of a first standard pressure change curve stored in advance, and whether the potential safety hazard exists in the key detection area is judged according to a comparison result; the method specifically comprises the following steps:

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;

and if the value A1 is larger than the value A2 and the difference of the values is larger than a seventh threshold value, judging that the electric core has potential safety hazard.

16. The method of claim 14, wherein the slope change of the first pressure change curve is compared with a slope change of a first standard pressure change curve stored in advance, and whether the potential safety hazard exists in the key detection area is judged according to a comparison result; the method specifically comprises the following steps:

the first standard pressure change curve is subjected to derivation to obtain a first standard curvature change curve corresponding to the first standard pressure change curve; the first pressure change curve is subjected to derivation to obtain a first curvature change curve corresponding to the first pressure change curve;

comparing a value B1 corresponding to the first curvature variation curve with a value B2 corresponding to the first curvature standard variation curve under the same electric quantity;

and if the value B1 is greater than the value B2 and the difference between the values is greater than an eighth threshold value, judging that the battery cell has potential safety hazards.

17. The method of claim 14, further comprising:

the preset criteria further include: a first non-standard pressure change curve of the key detection area; the first non-standard pressure change curve is a change curve of the expansion force of a key detection area along with the electric quantity when the battery cell is in a normal charging and discharging state until potential safety hazards occur;

analyzing and processing the pressure data of the key detection area in the first surface, and judging whether the potential safety hazard exists in the battery cell according to a preset standard, further comprising:

and comparing the slope change of the first pressure change curve with the slope change of a first non-standard pressure change curve, and judging whether the key detection area has potential safety hazards or not according to a comparison result.

18. The method of claim 13, further comprising:

analyzing and processing the pressure data of the non-key detection area in the first surface; the non-emphasis detection region is the other region outside the first surface emphasis detection region.

19. The method of claim 18,

the preset criteria further include: a second standard pressure change curve of the non-emphasized detection region; the second standard pressure change curve is a curve of the expansion force of the non-key detection area changing along with the electric quantity under the condition that the battery core is normally charged and discharged;

analyzing and processing pressure data of a non-key detection area in the first surface, and judging whether potential safety hazards exist in the battery cell according to preset standards, wherein the method specifically comprises the following steps:

drawing a second pressure change curve graph of the non-key detection area according to the pressure data;

and comparing the slope change of the second pressure change curve with the slope change of a second standard pressure change curve stored in advance, and judging whether the potential safety hazard exists in the battery cell according to a comparison result.

20. The method of claim 19, further comprising:

the preset criteria further include: a second non-standard pressure change curve of the non-emphasized detection region; the second non-standard pressure change curve is a change curve of the expansion force of the non-key detection area along with the electric quantity when the safety hazard occurs in a normal charging and discharging state;

analyzing the pressure data of the non-key detection area in the first surface, and judging whether the electric core has potential safety hazards according to a preset standard, further comprising:

and comparing the slope change of the second pressure change curve with the slope change of a second non-standard pressure change curve stored in advance, and judging whether the key detection area has potential safety hazards or not according to the comparison result.

21. The method of claim 18, wherein the pressure data of the emphasized sensing region in the first surface is analyzed and evaluated in real time; and analyzing and judging the pressure data of the non-key detection area in the first surface at a preset sampling frequency.

22. The intelligent safety detection device for the battery is characterized by comprising a pressure detection module and a control module, wherein the pressure detection module comprises a controller and pressure detection units, the number of the pressure detection units is not less than that of battery modules, and each pressure detection unit is provided with a film sensing piece and a data acquisition unit; the input end of the data acquisition unit is electrically connected with the film sensing sheet, the output end of the data acquisition unit is in communication connection with the controller, and the control module comprises a BMS (battery management system) in communication connection with the controller; the film sensing chip is configured to change at least one electrical parameter when being pressed, and the data collector is used for converting the electrical parameter data into pressure data and transmitting the pressure data to the controller;

the controller or the BMS is used for implementing the method for acquiring the cell emphasis detection area of any one of claims 1 to 12 and/or is used for implementing the battery intelligent safety detection method of any one of claims 13 to 21.

23. The intelligent battery safety detection device according to claim 22, wherein the battery includes at least two sets of battery modules, each set of battery modules includes at least one cell; the data collectors in the pressure detection units are electrically connected with the controller after being connected in parallel; or the data acquisition units in the pressure detection units are respectively electrically connected with the controller.

24. A vehicle comprising a driving device, a battery and the battery intelligent safety detection device according to claim 22 or 23.

25. An intelligent battery safety detection system is characterized by comprising a central control system and a plurality of intelligent battery safety detection devices; the intelligent safety detection device for the battery comprises a pressure detection module and a control module, wherein the pressure detection module comprises a controller and pressure detection units, the number of the pressure detection units is not less than that of battery modules, and each pressure detection unit is provided with a film sensing piece and a data acquisition unit; the input end of the data acquisition unit is electrically connected with the film sensing sheet, the output end of the data acquisition unit is in communication connection with the controller, and the control module comprises a BMS (battery management system) in communication connection with the controller; the film sensing chip is configured to change at least one electrical parameter when being pressed, and the data collector is used for converting the electrical parameter data into pressure data and transmitting the pressure data to the controller; the central control system is in communication connection with the BMS;

the central control system is used for implementing the method for acquiring the cell emphasis detection area according to any one of claims 1 to 12 and/or implementing the intelligent battery safety detection method according to any one of claims 13 to 21.