Method, device, medium and system for diagnosing local cooling fault of battery system

Abstract

The invention provides a method for diagnosing a local cooling fault of a battery system, and aims to accurately judge a fault of excessive local cooling or insufficient local cooling by monitoring temperature and voltage parameters of each region of the battery system in real time and combining charge and discharge state analysis. The method comprises the following specific steps: dividing a battery system into a plurality of monitoring areas, collecting the temperature of each area, the voltage of a battery unit and the charging and discharging state of the system in real time, dividing data time periods according to preset conditions, counting a temperature mean value T, a voltage mean value U and global statistics in each time period, and dynamically adjusting the C value of each area based on the charging and discharging state, and judging whether the region has an excessive or insufficient cooling fault or not through the C value. The battery internal resistance abnormal interference is eliminated through the principle of statistics, the false alarm rate is reduced in combination with a long-term data accumulation mechanism, the method can be realized only by upgrading the existing sensor and algorithm, and the method is suitable for electric automobiles, energy storage equipment and other scenes and has the advantages of high reliability and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly relates to a method, device, medium and system for diagnosing local cooling faults of a battery system. Background Art

[0002] Batteries represented by lithium-ion batteries are currently widely used in many fields such as electric vehicles, electrochemical energy storage devices, and power tools. Usually, multiple battery cells are connected in series and parallel to form a battery system to meet the requirements of energy storage and power output. During the charge and discharge process of the battery system, a large amount of heat is generated due to its own internal resistance. Therefore, a cooling device is usually used for thermal management of the battery system. On the one hand, the purpose is to suppress the excessive and rapid temperature rise of the battery system, and on the other hand, to maintain the temperature consistency of each area of the battery system, so as not to affect the performance of the battery system due to too high or too low local temperature.

[0003] The cooling devices of the battery system include various methods such as air cooling, liquid cooling, and phase change material cooling, and are usually exquisitely designed to meet the requirements of temperature rise suppression and temperature consistency of the battery system. However, faults may inevitably occur during the operation of the cooling device, so monitoring and diagnosis are required. For example, Chinese patents CN113511076A and CN112329357A both relate to methods for diagnosing the increased resistance fault of the liquid cooling pipeline for cooling an electric vehicle battery pack. Regarding the temperature consistency of the battery system caused by the self-fault of the cooling device, there is currently a lack of a scientific, reasonable, simple, easy-to-implement and highly reliable monitoring and diagnosis method, so new technical means are urgently needed. Summary of the Invention

[0004] The present invention provides a scientific, reasonable, simple, easy-to-implement and highly reliable method for diagnosing local cooling faults of a battery system, and provides a corresponding device, medium and system for diagnosing whether there are faults of local overcooling and / or undercooling during the operation of the battery system, so as to timely remind the user to check and maintain, in order to better maintain the temperature consistency of the battery system.

[0005] According to the first aspect of the present invention, a method for diagnosing local cooling faults of a battery system is provided. The battery system includes series-connected battery cells and a cooling device. The method is as follows:

[0006] Divide the battery system into several monitoring areas, and set the initial value of the cooling coefficient C of each area to 0;

[0007] Real-time collect the temperature of each area, the voltage of each battery cell, and the charge and discharge state of the system, where the charge and discharge state includes charging, discharging, and standby;

[0008] Divide the collected data into time periods, and the triggering condition for the division is to meet any of the following conditions:

[0009] 1) The number of acquisitions reaches the preset value;

[0010] 2) Changes in charge and discharge status;

[0011] Each time a time period is collected, the average temperature T and the average battery cell voltage U of each area in the time period are counted, as well as the mean value μ of all T values T and standard deviation σ T 、The mean value of all U values ​​μ U and standard deviation σ U :

[0012] If the time period is on hold:

[0013] 1) And there exists T>μ T +pσ T If the area is , the C value of the corresponding area is reduced by 1;

[0014] 2) And there exists T < μ T -pσ T If the area is , the C value of the corresponding area is increased by 1;

[0015] If the time period is charging state:

[0016] 1) And there exists T>μ T +pσ T And U<μ U +qσ U If the area is , the C value of the corresponding area is reduced by 1;

[0017] 2) There exists T<μ-pσ and U>μ U -qσ U If the area is , the C value of the corresponding area is increased by 1;

[0018] If the time period is the discharge state:

[0019] 1) And there exists T>μ T +pσ T And U>μ U -qσ U If the area is , the C value of the corresponding area is reduced by 1;

[0020] 2) There exists T < μ-pσ and U < μ U +qσ U If the area is , the C value of the corresponding area is increased by 1;

[0021] When the C value of a region is greater than C I Or when the net increase of C value within the preset time is greater than ΔC, the area is judged to be overcooled;

[0022] When the C value of a region is less than C IIIf the net decrease in the value of C within a preset time duration is greater than ΔC, it is determined that the cooling of this area is insufficient;

[0023] Where p and q above are coefficients greater than 0, and C I > 0 > C II .

[0024] Specifically, for the above-mentioned method for diagnosing local cooling faults in a battery system, the average voltage U of battery cells in a certain area within a certain time period is the average value of all voltage acquisition values of all battery cells included in this area within this time period.

[0025] Specifically, for the above-mentioned method for diagnosing local cooling faults in a battery system, the battery cell is composed of 1 battery monomer or multiple battery monomers connected in parallel.

[0026] Optionally, for the above-mentioned method for diagnosing local cooling faults in a battery system, the frequency of real-time data acquisition is between 0.05 Hz and 1 Hz; the preset value of the number of acquisitions for dividing the acquisition data into time periods is between 10 and 1000; the preset time duration for determining whether there is over-cooling or under-cooling in an area is between 10 minutes and 100 hours.

[0027] Optionally, for the above-mentioned method for diagnosing local cooling faults in a battery system, both coefficients p and q are between 1 and 3, and C I is between 20 and 500, and C II is between -500 and -20, and ΔC is between 10 and 1000.

[0028] According to the second aspect of the present invention, there is provided a device for diagnosing local cooling faults in a battery system, which is used to implement the method for diagnosing local cooling faults in a battery system described in any one of the above, and this device includes an acquisition module, a storage module, an analysis module and an output module:

[0029] The acquisition module includes a temperature sensor, a voltage sensor and a current sensor, which are respectively used for acquiring the temperature of each area, the voltage of each battery cell and the charge and discharge state of the system;

[0030] The storage module is used to receive the data acquired by the acquisition module and store it;

[0031] The analysis module is used to read data from the storage module and perform fault diagnosis and analysis;

[0032] The output module is used to obtain the diagnosis result from the analysis module and output it.

[0033] According to the third aspect of the present invention, there is provided a computer-readable storage medium storing multiple computer instructions, and these computer instructions are suitable for being loaded by a processor to execute the method for diagnosing local cooling faults in a battery system described in any one of the above.

[0034] According to the fourth aspect of the present invention, there is provided a battery system integrated with the diagnostic device for the local cooling failure of the above battery system.

[0035] Optionally, the above battery system is mounted on an electric vehicle.

[0036] Optionally, the above battery system is mounted on a battery energy storage device.

[0037] The beneficial effects thereof will be introduced below in conjunction with the principle of the technical solution of the present invention.

[0038] The temperature of a certain area of the battery system mainly depends on the heat generation during the charge and discharge process of the battery cells in that area and the cooling intensity applied to that area by the cooling device. Since the battery cells are in series, the current passing through them is equal. Therefore, the heat generation of each battery cell is related to its internal resistance, and the magnitude of the internal resistance is usually reflected by the degree of deviation of the voltage from the equilibrium potential during the charge and discharge process: during the charging process, the voltage of the battery is higher than the equilibrium potential. Under the same conditions, the higher the voltage of the battery cell, the greater the internal resistance, and the corresponding heat generation power is also higher; during the discharging process, the voltage of the battery is lower than the equilibrium potential. Under the same conditions, the lower the voltage of the battery cell, the greater the internal resistance, and the corresponding heat generation power is also higher.

[0039] The present invention first divides the battery system into several areas and assigns an initial value of 0 to the cooling coefficient C of each area.

[0040] Then, during the operation of the battery system, every time the acquisition data for a period of time is obtained, it is analyzed and processed to adjust the value of the cooling coefficient C of each area, and the battery system is only in the same working state within the same period of time. Specifically, every time the acquisition data for a period of time is obtained, the average temperature T and the average battery cell voltage U of each area within that period of time are statistically calculated, as well as the mean μ T and the standard deviation σ T of all T values, the mean μ U and the standard deviation σ U of all U values, and the value of the cooling coefficient C of each area is adjusted:

[0041] (1) If the period is a standby state, then there is no current passing through the battery system, and the battery itself hardly generates heat. It only needs to directly judge whether there is a high or low temperature in that area according to the statistical principle:

[0042] 1) When there is an area where T > μ T + pσ T , then these areas are relatively high in temperature compared to the whole, and it is initially considered that the cooling may be insufficient, and the C value of the corresponding area is decreased by 1;

[0043] 2) When there is an area where T < μ T - pσ TWhen in these areas, the temperature of these areas is relatively low compared to the whole. It is initially considered that there may be excessive cooling, and the C value of the corresponding area is increased by 1.

[0044] (2) If the time period is in the charging state, the battery system generates heat due to charging itself, and it is necessary to further rule out whether the abnormal temperature is related to the abnormal heat generation of the battery itself

[0045] 1) When there are areas where T > μ T + pσ T It indicates that the temperature of these areas is relatively high. At the same time, if it is further found that U < μ U + qσ U in the corresponding areas, it means that there is no phenomenon of high voltage in these areas. It is initially considered that the relatively high temperature may be caused by insufficient cooling rather than excessive internal resistance. Therefore, the C value of the corresponding area is decreased by 1;

[0046] 2) When there are areas where T < μ - pσ, it means that the temperature of these areas is relatively low. At the same time, if it is further found that U > μ U - qσ U in the corresponding areas, it means that there is no phenomenon of low voltage in these areas. It is initially considered that the relatively low temperature may be caused by excessive cooling rather than too small internal resistance, and the C value of the corresponding area is increased by 1;

[0047] If the time period is in the discharging state:

[0048] 1) When there are areas where T > μ T + pσ T It indicates that the temperature of these areas is relatively high. At the same time, if it is further found that U > μ U - qσ U in the corresponding areas, it means that there is no phenomenon of low voltage in these areas. It is initially considered that the relatively high temperature may be caused by insufficient cooling rather than excessive internal resistance. Therefore, the C value of the corresponding area is decreased by 1;

[0049] 2) When there are areas where T < μ - pσ, it means that the temperature of these areas is relatively low. At the same time, if it is further found that U < μ U + qσ U in the corresponding areas, it means that there is no phenomenon of high voltage in these areas. It is initially considered that the relatively low temperature may be caused by excessive cooling rather than too small internal resistance, and the C value of the corresponding area is increased by 1.

[0050] The judgment result of a single time period during the operation of the battery system can only be used as a preliminary judgment. To avoid false alarms, it still needs long-term and large-scale statistical verification to draw a final conclusion. Because there may be temporary fluctuations and instabilities in the actual operation process due to various factors. For example, for a specific area, the C value may increase in a certain time period while it may decrease in other time periods, and in the long run, the C value is basically stable around its initial value of 0.

[0051] When the C value of a region is greater than C I , it means that its C value has accumulated and increased over a long period of time, so it can be determined that the area is overcooled; when the net increase of the C value of a certain area within the preset time is greater than ΔC, it means that its C value has a trend of rapidly increasing, and it can also be determined that the area is overcooled.

[0052] Correspondingly, when the C value of a region is less than C II , it means that its C value has been accumulating and decreasing in the long term, so it can be determined that the area is not cooled enough; when the net decrease in the C value of a certain area within the preset time is greater than ΔC, it means that its C value has a trend of rapidly decreasing, and it can also be determined that the area is not cooled enough.

[0053] Insufficient local cooling and excessive local cooling in various areas are considered local cooling failure problems that have a significant impact on the temperature consistency of various parts of the battery system. The reasons are multifaceted, such as local pipe blockage, uneven fluid distribution, and too tight or too loose fit between the cold plate and the battery cell. These problems are difficult to detect during the operation of the battery system.

[0054] From the above principles, it is not difficult to find that the technical solution of the present invention has the following beneficial effects:

[0055] (1) With the help of heat transfer, electrochemistry and statistical principles, the local cooling intensity that affects the temperature of the battery system area and the heat generation power of the battery in the area are taken into consideration. When judging whether there is insufficient or excessive local cooling, the possibility of abnormal heat generation caused by abnormal internal resistance of the battery in the corresponding area is first excluded, so it is scientific and reasonable;

[0056] (2) The temperature, voltage and current sensors involved in the relevant diagnostic devices are common configurations of existing battery systems. Therefore, they basically only need to be supplemented at the software level to complete the adaptation of existing battery system products. They are low in cost, easy to implement, and highly versatile. They are also suitable for typical application scenarios of battery systems such as electric vehicles and battery energy storage.

[0057] (3) When it is preliminarily determined that abnormal temperatures occur in certain areas during a certain period of time, the system does not rush to draw conclusions. Instead, it finally diagnoses local cooling failures after sufficient data has been accumulated and has statistical significance. Therefore, the system is highly reliable and can avoid false alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The figure is a flow chart of a method for diagnosing a local cooling fault of a battery system according to an embodiment of the present invention.

[0059] Figure 2 Schematic diagram of a local cooling fault diagnosis device for a battery system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0061] As Figure 1 shown, a diagnostic method for a local cooling failure of a battery system, the battery system comprising series-connected battery cells and a cooling device, the method being:

[0062] Divide the battery system into several monitoring areas, and set the initial value of the cooling coefficient C of each area to 0;

[0063] Collect the temperature of each area, the voltage of each battery cell, and the charge and discharge state of the system in real time, where the charge and discharge state includes charging, discharging, and standby;

[0064] Divide the collected data into time periods, and the division trigger condition is to meet any of the following conditions:

[0065] 1) The number of acquisitions reaches a preset value;

[0066] 2) The charge and discharge state changes;

[0067] For each set of acquisition data for a time period, calculate the average temperature T and the average battery cell voltage U of each area during this time period, as well as the mean μ T and standard deviation σ T of all T values, the mean μ U and standard deviation σ U of all U values:

[0068] If this time period is in the standby state:

[0069] 1) When there is an area where T > μ T + pσ T , decrease the C value of the corresponding area by 1;

[0070] 2) When there is an area where T < μ T - pσ T , increase the C value of the corresponding area by 1;

[0071] If this time period is in the charging state:

[0072] 1) When there is an area where T > μ T + pσ T and U < μ U + qσ U , decrease the C value of the corresponding area by 1;

[0073] 2) When there is an area where T < μ - pσ and U > μ U - qσ U , increase the C value of the corresponding area by 1;

[0074] If this time period is in the discharging state:

[0075] 1) When there is coexistence and T > μ T + pσ T and U > μ U - qσ U in a region, the C value of the corresponding region is decreased by 1;

[0076] 2) When there is coexistence and T < μ - pσ and U < μ U + qσ U in a region, the C value of the corresponding region is increased by 1;

[0077] When the C value of a certain region is greater than C I or the net increase in the C value within a preset time duration is greater than ΔC, it is determined that the cooling of this region is excessive;

[0078] When the C value of a certain region is less than C II or the net decrease in the C value within a preset time duration is greater than ΔC, it is determined that the cooling of this region is insufficient;

[0079] Here, p and q are coefficients greater than 0, and C I > 0 > C II .

[0080] Specifically, the battery unit is composed of one battery cell or multiple battery cells connected in parallel.

[0081] Specifically, the monitoring regions of the battery system can be divided according to the structural characteristics of the battery system and its cooling device.

[0082] In one embodiment, the cooling device is a liquid cooling plate with liquid inlet at one end and liquid outlet at the other end. Along the upstream and downstream of the coolant flow channel and considering the relationship of each flow channel branch, the battery system is divided into 20 monitoring regions.

[0083] In another embodiment, the battery system is composed of 30 modules, and then the battery system is divided into 30 monitoring regions according to the regions where the modules are located, with each region corresponding to 1 module.

[0084] Specifically, the number of battery units in each region can be equal or unequal.

[0085] Specifically, for the above - mentioned method for diagnosing local cooling faults of the battery system, the average voltage U of the battery units in a certain region within a certain time period is the average of all voltage acquisition values of all the battery units included in this region within this time period.

[0086] In one embodiment, there are 10 battery units in a certain region. The average voltage U of the battery units in this region within a certain time period is the average of all voltage acquisition values of all the 10 battery units included in this region within this time period.

[0087] Preferably, for the above-mentioned diagnostic method for local cooling failure of the battery system, the frequency of real-time data acquisition is between 0.05 Hz and 1 Hz; the preset value of the number of acquisitions for dividing the acquisition data into time periods is between 10 and 1000; the preset duration for determining whether there is excessive or insufficient regional cooling is between 10 minutes and 100 hours.

[0088] Preferably, for the above-mentioned diagnostic method for local cooling failure of the battery system, both the coefficients p and q are between 1 and 3, C I is between 20 and 500, C II is between -500 and -20, and ΔC is between 10 and 1000.

[0089] As Figure 2 shown, a diagnostic device for local cooling failure of a battery system is used to implement the above-mentioned diagnostic method for local cooling failure of the battery system. The device includes an acquisition module, a storage module, an analysis module, and an output module:

[0090] The acquisition module includes a temperature sensor, a voltage sensor, and a current sensor, which are respectively used for acquiring the temperature of each region, the voltage of each battery cell, and the charge and discharge state of the system;

[0091] The storage module is used to receive and store the data acquired by the acquisition module;

[0092] The analysis module is used to read data from the storage module and perform fault diagnosis and analysis;

[0093] The output module is used to obtain the diagnostic result from the analysis module and output it.

[0094] Specifically, at least one temperature sensor is set in each region. If there are more than one temperature sensor set in a single region, the average value of the temperature measurements of all temperature sensors is used as the acquisition value for output.

[0095] Preferably, the temperature sensor is disposed on the surface of the battery cell.

[0096] Preferably, the output module can communicate with the BMS (Battery Management System) of the battery system to upload the diagnostic result.

[0097] The present invention also provides a computer-readable storage medium storing multiple computer instructions, and the computer instructions are suitable for being loaded by a processor to execute the above-mentioned diagnostic method for local cooling failure of the battery system.

[0098] The present invention also provides a battery system integrated with the above-mentioned diagnostic device for local cooling failure of the battery system.

[0099] Furthermore, the above-mentioned battery system can be mounted on an electric vehicle.

[0100] Further, the above battery system can also be mounted on a battery energy storage device.

[0101] Embodiment

[0102] Please refer to Figures 1 to 2 to understand a more specific embodiment. The battery system in this embodiment is composed of 2 parallel-connected and 100 series-connected lithium iron phosphate lithium-ion battery monomers, so each battery unit is composed of 2 parallel-connected battery monomers. The battery system uses a liquid cooling plate to exchange heat with each battery unit, and divides the battery system into 20 monitoring areas numbered from 1# to 20# according to the upstream, downstream, and branch characteristics of the liquid cooling channels. Each monitoring area is equipped with 1 temperature sensor, for a total of 20 temperature sensors; each battery unit is equipped with 1 voltage sensor, for a total of 100 voltage sensors; a Hall sensor is provided at the total positive connection terminal output by the battery system to measure the current of the battery system, so as to judge its working state.

[0103] In this embodiment, the frequency of real-time data acquisition = 1 Hz, the preset value of the number of acquisitions for dividing the acquisition data into time periods is 100, the preset duration for judging whether there is excessive or insufficient cooling in a region = 30 minutes, coefficient p = 2.5, q = 2, C I = 100, C II = -100, ΔC = 30.

[0104] One day, the battery system starts to work. Denote the start time as t = 0. At this time, the C values of the cooling coefficients of each region are all set to 0.

[0105] Taking the first 1000 s as an example, the system is in a discharging state from t = 0 to t = 560 s, in a standby state from t = 561 s to t = 700 s, and in a charging state from t = 701 s to t = 1000 s. Then, the time periods for dividing the acquisition data are shown in Table 1. In Table 1, the time periods are numbered in chronological order for easy understanding.

[0106] Table 1 Division of time periods for acquisition data in the first 1000 s

[0107] Number Start and end time System status 1 0 to 100 s Discharge 2 101 to 200 s Discharge 3 201 to 300 s Discharge 4 301 to 400 s Discharge 5 401 to 500 s Discharge 6 501 to 560 s Discharge 7 561 to 660 s Idle 8 661 to 700 s Idle 9 701 to 800 s Charge 10 801 to 900 s Charge 11 901 to 1000 s Charge

[0108] Next, the 1# monitoring area will be mainly introduced as an example.

[0109] During the time period numbered 120, the C value of the 1# monitoring area is 4.

[0110] During the time period numbered 121, the 1# monitoring area is in a standby state, with an average temperature T = 42.3 °C and an average battery unit voltage U = 3.31 V; the average value μ T of all T values in the 20 monitoring areas T= 0.26 °C, the mean value μ of all U values U = 3.30 V, the standard deviation σ U = 0.006 V. Since μ T + pσ T = 41.8 + 2.5 * 0.26 = 42.45 °C, μ T - pσ T = 41.8 - 2.5 * 0.26 = 41.15 °C, so for the 1# monitoring area, during the time period numbered 121, T > μ T + pσ T and T < μ T - pσ T conditions are not satisfied, the C value remains unchanged, still 4.

[0111] During the time period numbered 122, the 1# monitoring area is in a discharging state, its average temperature T = 44.5 °C, the average battery cell voltage U = 3.20 V; the mean value μ of all T values of 20 monitoring areas T = 43.7 °C, the standard deviation σ T = 0.29 °C, the mean value μ of all U values U = 3.19 V, the standard deviation σ U = 0.007 V. Since μ T + pσ T = 43.7 + 2.5 * 0.29 = 44.43 °C, μ U - qσ U = 3.19 - 2 * 0.007 = 3.176 V, so for the 1# monitoring area, during the time period numbered 122, T > μ T + pσ T and U > μ U - qσ U is satisfied, let C decrease by 1, and its value changes to 3.

[0112] During the time period numbered 123, the 1# monitoring area is in a charging state, its average temperature T = 45.9 °C, the average battery cell voltage U = 3.34 V; the mean value μ of all T values of 20 monitoring areas T = 44.9 °C, the standard deviation σ T = 0.32 °C, the mean value μ of all U values U = 3.33 V, the standard deviation σ U = 0.006 V. Since μ T + pσ T = 44.9 + 2.5 * 0.32 = 45.7 °C, μ U + qσ U = 3.33 + 2 * 0.006 = 3.342 V, so for the 1# monitoring area, during the time period numbered 123, T > μT +pσ T and U < μ U +qσ U holds. Let C be decreased by 1 and its value be changed to 2.

[0113] After several time periods, the C value of the 1# monitoring area is -101, which is less than C II , so the output module of the diagnostic device outputs the local cooling fault information of insufficient cooling in the 1# monitoring area to the BMS of the battery system.

[0114] The technical solution in this embodiment is based on the principles of heat transfer, electrochemistry and statistics, fully considering the correlation between the regional temperature of the battery system, the local cooling intensity and the heat generation power, judging the cooling intensity on the premise of excluding the heat generation deviation caused by abnormal battery internal resistance, and the diagnosis process relies on the existing temperature / voltage / current sensors to achieve hardware compatibility, and only needs to be supplemented with software algorithms to adapt to typical scenarios such as electric vehicles and energy storage. The final diagnosis decision adopts a data accumulation mechanism, and the fault diagnosis is triggered only after verifying the temperature anomaly phenomenon in the statistical sense, which can effectively reduce the false alarm rate. Therefore, the technical solution is scientific, reasonable, simple and reliable.

Claims

1. A method for diagnosing a local cooling failure of a battery system, wherein the battery system comprises battery cells connected in series and a cooling device, wherein: The battery system is divided into several monitoring areas, and the initial value of the cooling coefficient C of each area is set to 0; Real-time collection of the temperature of each area, the voltage of each battery unit and the system charging and discharging status, where the charging and discharging status includes charging, discharging and shelving; The collected data is divided into time periods, and the division trigger condition is to meet any of the following conditions: 1) The number of acquisitions reaches the preset value; 2) Changes in charge and discharge status; Each time a time period is collected, the average temperature T and the average battery cell voltage U of each area in the time period are counted, as well as the mean value μ of all T values T and standard deviation σ T 、The mean value of all U values ​​μ U and standard deviation σ U : If the time period is on hold: 1) And there exists T>μ T +pσ T If the area is , the C value of the corresponding area is reduced by 1; 2) And there exists T < μ T -pσ T If the area is , the C value of the corresponding area is increased by 1; If the time period is charging state: 1) And there exists T>μ T +pσ T And U<μ U +qσ U If the area is , the C value of the corresponding area is reduced by 1; 2) There exists T<μ-pσ and U>μ U -qσ U If the area is , the C value of the corresponding area is increased by 1; If the time period is the discharge state: 1) And there exists T>μ T +pσ T And U>μ U -qσ U If the area is , the C value of the corresponding area is reduced by 1; 2) There exists T < μ-pσ and U < μ U +qσ U If the area is , the C value of the corresponding area is increased by 1; When the C value of a region is greater than C I Or when the net increase of C value within the preset time is greater than ΔC, the area is judged to be overcooled; When the C value of a region is less than C II Or when the net decrease in C value within the preset time is greater than ΔC, it is determined that the area is insufficiently cooled; Above, p and q are coefficients greater than 0, C I >0>C II .

2. The method for diagnosing a local cooling failure of a battery system according to claim 1, characterized in that: The average voltage U of the battery cells in a certain area within a certain time period is the average value of all voltage collection values ​​of all the battery cells contained in the area within the time period.

3. The method for diagnosing a local cooling failure of a battery system according to claim 1, characterized in that: The battery unit is composed of one battery cell or a plurality of battery cells connected in parallel.

4. The method for diagnosing a local cooling failure of a battery system according to claim 1, characterized in that: The frequency of real-time data collection is between 0.05Hz and 1Hz; the preset value of the number of collection times for dividing the collected data into time periods is between 10 and 1000; the preset time for determining whether there is excessive or insufficient cooling of a region is between 10 minutes and 100 hours.

5. The method for diagnosing a local cooling failure of a battery system according to claim 1, characterized in that: The coefficients p and q are both between 1 and 3, C I Between 20 and 500, C II Between -500 and -20, ΔC between 10 and 1000.

6. A battery system local cooling fault diagnosis device, used to implement the battery system local cooling fault diagnosis method according to any one of claims 1 to 5, characterized in that: Including acquisition module, storage module, analysis module and output module: The acquisition module includes a temperature sensor, a voltage sensor, and a current sensor, which are used to collect the temperature of each area, the voltage of each battery unit, and the charging and discharging status of the system; The storage module is used to receive and store the data collected by the collection module; The analysis module is used to read data from the storage module and perform fault diagnosis analysis; The output module is used to obtain and output the diagnostic results from the analysis module.

7. A computer-readable storage medium storing a plurality of computer instructions, characterized in that: The computer instructions are suitable for loading into a processor to execute the method for diagnosing a local cooling fault of a battery system according to any one of claims 1 to 5.

8. A battery system, characterized in that: The device is integrated with the diagnostic device for local cooling failure of the battery system as claimed in claim 6.

9. The battery system according to claim 8, characterized in that: Installed in electric vehicles.

10. The battery system according to claim 8, characterized in that: Mounted on battery energy storage equipment.

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