Method for monitoring power battery, vehicle and storage medium

Abstract

This application discloses a monitoring method for a power battery, a vehicle, and a storage medium, relating to the field of vehicle technology. The method includes: acquiring voltage parameters of the power battery; when the voltage parameters meet preset conditions, performing time integration on the current of the power battery to obtain the ampere-hour difference value between different cells in the power battery; determining whether there are cells with abnormal self-discharge rates in the power battery based on the ampere-hour difference value; wherein the preset conditions indicate that the voltage of the power battery is located in a non-plateau region between different plateau regions. This application aims to improve the timeliness of detecting cells with abnormal self-discharge rates, thereby improving the timeliness of battery maintenance.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method for monitoring power batteries, vehicles, and storage media. Background Technology

[0002] Cells with high self-discharge rates after long-term idling or exposure to external forces can affect the overall consistency of the battery pack, thereby impacting battery performance and reducing vehicle range.

[0003] In related technologies, when the power battery is in a low-charge resting state (charge below 25%), the charge of each cell is deduced by detecting the open-circuit voltage. The difference between the maximum and minimum charge of the recorded cells is used to determine whether there are cells with abnormal self-discharge rates. However, the low-charge resting conditions of power batteries (especially lithium iron phosphate batteries) during vehicle use are limited. Therefore, the above detection method cannot detect cells with abnormal self-discharge rates in a timely manner, resulting in untimely battery maintenance. Summary of the Invention

[0004] The main objective of this application is to provide a method for monitoring power batteries, a vehicle, and a storage medium, which aims to improve the timeliness of detecting cells with abnormal self-discharge rates, thereby improving the timeliness of battery maintenance.

[0005] To achieve the above objectives, this application proposes a method for monitoring a power battery, the method comprising: Obtain the voltage parameters of the power battery; When the voltage parameters meet the preset conditions, the current of the power battery is integrated over time to obtain the ampere-hour difference value between different cells in the power battery. The presence of cells with abnormal self-discharge rates in the power battery is determined based on the difference in ampere-hours. The preset condition indicates that the voltage of the power battery is located in the non-platform area between different platform areas.

[0006] In one embodiment, the voltage parameters include the minimum cell voltage and the maximum cell voltage of the power battery; The preset conditions include: the minimum cell voltage is greater than the lower limit voltage of the first plateau region of the power battery, the maximum cell voltage is less than the upper limit voltage of the second plateau region of the power battery, and the voltage difference between the maximum cell voltage and the minimum cell voltage is greater than the voltage difference threshold.

[0007] In one embodiment, the monitoring method for the power battery further includes: The lower limit voltage, the upper limit voltage, and the voltage difference threshold are determined based on the minimum cell temperature of the power battery.

[0008] In one embodiment, the step of determining whether the power battery has cells with abnormal self-discharge rates based on the ampere-hour difference value includes: The characteristic value of the capacity difference of different cells in the power battery is determined based on at least two of the said ampere-hour difference values; The presence of cells with abnormal self-discharge rates in the power battery is determined based on the aforementioned characteristic values.

[0009] In one embodiment, the at least two ampere-hour difference values ​​are detected in different slow charging states, and / or, the monitoring method for the power battery further includes: Obtain the initial charge corresponding to each of the ampere-hour difference values, where the initial charge is the charge of the power battery when it enters the slow charging state corresponding to the ampere-hour difference value; Based on the initial power consumption, determine the corresponding weight value of the ampere-hour difference value, and obtain at least two weight values; The step of determining the characteristic value of the capacity difference of different cells in the power battery based on at least two of the ampere-hour difference values ​​includes: The characteristic value is obtained by weighting at least two ampere-hour difference values ​​with at least two weight values.

[0010] In one embodiment, the monitoring method for the power battery further includes: When the power battery is in a slow charging state, after obtaining the voltage parameters of the power battery, the step of performing time integration on the current of the power battery under the condition that the voltage parameters meet the preset conditions is executed to obtain the ampere-hour difference value between different cells in the power battery. When the power battery is in a preset state, after acquiring the voltage parameters of the power battery, if the voltage parameters meet the preset conditions and continue for a preset duration, it is determined that the power battery has a cell with an abnormal self-discharge rate; the preset state includes the power battery being in a discharging state and the discharge current being within a set current range.

[0011] In one embodiment, the set current range is [-10A, 10A]; and / or, the monitoring method for the power battery further includes: When the power battery is in the slow charging state, the initial charge level of the power battery when it enters the slow charging state is obtained; When the initial charge is less than the charge threshold, the step of performing time integration on the current of the power battery to obtain the ampere-hour difference value between different cells in the power battery is executed when the voltage parameter meets the preset conditions.

[0012] In one embodiment, the monitoring method for the power battery further includes: Obtain the temperature status parameters of the power battery when it enters the slow charging state and / or the resting time of the power battery before it enters the slow charging state; The power threshold is determined based on the temperature status parameter and / or the resting time.

[0013] In one embodiment, the temperature status parameters include the maximum cell temperature and the minimum cell temperature, and the step of determining the charge threshold based on the temperature status parameters and / or the resting time includes: Determine the cell temperature difference between the maximum cell temperature and the minimum cell temperature; The power threshold is determined based on the cell temperature difference, the minimum cell temperature, and the resting time.

[0014] Furthermore, to achieve the above objectives, this application also proposes a vehicle including a power battery and a battery management device connected together. The battery management device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The computer program is configured to implement the steps of the power battery monitoring method described above.

[0015] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the power battery monitoring method described above.

[0016] The present application proposes one or more technical solutions, which have at least the following technical effects: When the voltage parameters of the power battery meet preset conditions, indicating that the voltage of the power battery is located in the non-platform region between different plateau regions, the current of the power battery is integrated over time to obtain the ampere-hour difference value between different cells in the power battery, and the presence of cells with abnormal self-discharge rate is determined based on the ampere-hour difference value. Based on this, the detection of cells with abnormal self-discharge rate in the power battery does not need to wait for the low charge static condition, thereby effectively improving the timeliness of detecting cells with abnormal self-discharge rate and improving the timeliness of battery maintenance. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the equipment structure of the hardware operating environment involved in the power battery monitoring method in the embodiments of this application; Figure 2 A flowchart illustrating the first embodiment of the power battery monitoring method of this application; Figure 3 This is a flowchart illustrating the slow charging process in Embodiment 2 of the power battery monitoring method of this application. Figure 4 This is a schematic diagram showing the voltage change over time of a lithium iron phosphate battery during charging, which is used in the monitoring method for the power battery of this application.

[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0022] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The main solution of this application embodiment is: to obtain the voltage parameters of the power battery; when the voltage parameters meet the preset conditions, to perform time integration on the current of the power battery to obtain the ampere-hour difference value between different cells in the power battery; to determine whether there are cells with abnormal self-discharge rate in the power battery based on the ampere-hour difference value; wherein, the preset conditions indicate that the voltage of the power battery is located in the non-plateau region between different plateau regions.

[0024] In this embodiment, for ease of description, the following description uses a vehicle as the executing entity.

[0025] In related technologies, when the power battery is at a low charge level (below 25%), the charge of each cell is deduced by detecting the open-circuit voltage. The difference between the maximum and minimum charge of the recorded cells is used to determine if there are cells with abnormal self-discharge rates. However, the low-charge resting conditions of power batteries (especially lithium iron phosphate batteries) during vehicle use are limited. Therefore, the above detection method cannot detect cells with abnormal self-discharge rates in a timely manner, leading to untimely battery maintenance.

[0026] This application provides the above-mentioned solution, which, when the voltage parameters of the power battery meet preset conditions, indicating that the voltage of the power battery is located in the non-plateau region between different plateau regions, integrates the current of the power battery over time to obtain the ampere-hour difference value between different cells in the power battery, and determines whether there are cells with abnormal self-discharge rate based on the ampere-hour difference value. Based on this, the detection of whether there are cells with abnormal self-discharge rate in the power battery does not need to wait for the low charge static condition, thereby effectively improving the timeliness of detecting cells with abnormal self-discharge rate and improving the timeliness of battery maintenance.

[0027] This application provides an embodiment of a vehicle. The vehicle may be a pure electric vehicle or a hybrid vehicle, etc.

[0028] In this embodiment, refer to Figure 1 The vehicle includes a power battery 200 and a battery management device 100, which are electrically connected to the power battery 200.

[0029] In this embodiment, the power battery 200 is a lithium iron phosphate battery or the like. The power battery 200 includes multiple cells, which are connected in series or in parallel.

[0030] The battery management device 100 includes: at least one processor 1001; and a memory 1002 communicatively connected to the at least one processor 1001, and a timer 1003, etc.; wherein the memory 1002 stores instructions that can be executed by the at least one processor 1001, and the instructions are executed by the at least one processor 1001 to enable the at least one processor 1001 to execute the power battery charging control method in the following embodiment.

[0031] The following is for reference. Figure 1 It shows a structural schematic diagram of a battery management device 100 suitable for implementing embodiments of this application. Figure 1 The battery management device 100 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0032] like Figure 1As shown, the battery management device 100 may include a processor 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a memory 1002. The program in the memory 1002 may be a program in read-only memory (ROM) or a program loaded from a storage device into random access memory (RAM). The RAM also stores various programs and data required for the operation of the battery management device 100. The processor 1001 and the memory 1002 (ROM and RAM) are interconnected via a bus. An input / output (I / O) interface is also connected to the bus. Typically, the following systems can be connected to the I / O interface: input devices including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices including, for example, magnetic tapes, hard disks, etc.; and communication devices. The communication device allows the battery management device 100 to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a battery management device 100 with various systems, it should be understood that it is not required to implement or have all of the systems shown. More or fewer systems may be implemented alternatively.

[0033] Specifically, according to the embodiments disclosed in this application, the method flow described in the following embodiments can be implemented as a computer software program. For example, the embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device. When the computer program is executed by the processor 1001, it performs the functions defined in the charging control method for a power battery according to the embodiments disclosed in this application.

[0034] The vehicle provided in this application, employing the power battery charging control method described in the following embodiments, solves the technical problem of how to improve the timeliness of detecting cells with abnormal self-discharge rates, thereby improving the timeliness of battery maintenance. Compared with the prior art, the beneficial effects of the vehicle provided in this application are the same as those of the power battery charging control method provided in the following embodiments, and other technical features of the vehicle are the same as those disclosed in the method of the following embodiments, and will not be repeated here.

[0035] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device or vehicle capable of performing the above functions. The following description uses a vehicle as an example to illustrate this embodiment and the subsequent embodiments.

[0036] Based on this, embodiments of this application provide a method for monitoring a power battery, referring to... Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of the power battery monitoring method of this application.

[0037] In this embodiment, the monitoring method for the power battery includes steps S10 to S30: Step S10: Obtain the voltage parameters of the power battery; Voltage parameters may include at least one of the following: maximum cell voltage, minimum cell voltage, average cell voltage, voltage variation, etc. In this embodiment, voltage parameters include maximum cell voltage and minimum cell voltage.

[0038] In this embodiment, step S10 can be performed when the power battery is in a charging state or a discharging state.

[0039] The maximum and minimum cell voltages obtained here can be acquired by sliding filtering sampling over a set duration (e.g., 1 second or longer) to suppress the impact of instantaneous sampling fluctuations on subsequent self-discharge anomaly detection results.

[0040] Step S20: When the voltage parameter meets the preset conditions, the current of the power battery is integrated over time to obtain the ampere-hour difference value between different cells in the power battery; wherein, the preset conditions indicate that the voltage of the power battery is located in the non-plateau region between different plateau regions. In this embodiment, combined with Figure 4 The preset conditions include that the minimum cell voltage is greater than the lower limit voltage of the first plateau region of the power battery, the maximum cell voltage is less than the upper limit voltage of the second plateau region of the power battery, and the voltage difference between the maximum cell voltage and the minimum cell voltage is greater than a voltage difference threshold. The lower limit voltage, upper limit voltage, and voltage difference threshold can be preset fixed values ​​or parameter values ​​determined based on the actual operating parameters of the power battery. Specifically, the voltage of each cell in the power battery is detected, and the maximum value among all obtained voltages is taken as the maximum cell voltage, and the minimum value among all obtained voltages is taken as the minimum cell voltage.

[0041] The first plateau region can be a low-voltage plateau region, and the second plateau region can be a high-voltage plateau region. The lower limit voltage is the starting voltage at the beginning of the low-voltage plateau region during charging or discharging, and the upper limit voltage is the ending voltage at the end of the high-voltage plateau region during charging or discharging. The upper and lower limit voltages are affected by cell characteristics, current magnitude, temperature, and temperature difference.

[0042] The differential pressure threshold is affected by the preceding operating conditions, the initial SOC when entering the current charging or discharging state, the resting time before entering the current charging or discharging state, the minimum temperature, the temperature difference, the differential pressure in the non-platform zone in the middle of the current charging or discharging state, the charging current, and the self-discharge difference.

[0043] In this embodiment, to improve the accuracy of self-discharge anomaly identification, the lower limit voltage, the upper limit voltage, and the voltage difference threshold are determined based on the minimum cell temperature of the power battery. Specifically, the cell temperature of each cell in the power battery can be obtained, and the minimum value among all cell temperatures is the minimum cell temperature.

[0044] The current here refers to the real-time current value detected when the voltage parameters meet preset conditions. In the charging state (e.g., slow charging), the ampere-hour difference is obtained by integrating the charging current of the power battery over time; in the discharging state, the ampere-hour difference is obtained by integrating the discharging current of the power battery over time. The ampere-hour difference value deltaAH can be calculated using the following formula: deltaAH = Σ(curr*ts) / 3600; where curr is the instantaneous current, ts is the sampling time interval (in seconds); curr×ts represents the charge / discharge amount within a single sampling period; Σcurr*ts represents the sum of curr×ts in all sampling periods within the target time period, equivalent to the discrete summation form of ∫Idt; / 3600 represents converting the total time from seconds to hours.

[0045] The ampere-hour difference value can be the result of current integration within the target time period. In some implementations, the voltage parameters of the power battery can be detected at set intervals. The initial moment is when the voltage parameter changes from not meeting the preset conditions to meeting the preset conditions, and the end moment is when the voltage parameter changes from meeting the preset conditions to not meeting the preset conditions. The time period between the initial moment and the end moment is the reference time period. The entire reference time period can be used as the target time period, or a part of the reference time period can be used as the target time period. For example, the period when the power battery charge is less than a preset charge threshold and / or the temperature difference within the power battery is within a preset temperature difference range can be used as the target time period, and so on.

[0046] The Ampere-hour difference (AHD) is the equivalent difference in charge capacity between different cells during the charging and discharging process of a power battery, caused by differences in self-discharge. In the charging and discharging state, the AHDD is the equivalent difference in the amount of charge required to replenish the charge of different cells; in the discharging state, the AHDD is the equivalent difference in the amount of charge that can be released by different cells.

[0047] When the power battery voltage is in the plateau region, the voltage of each cell changes very little with the state of charge and tends to be stable. Under the flattening voltage characteristics of the plateau region, the difference in SOC charge between cells cannot be clearly distinguished by voltage. However, the voltage of the plateau region between different plateau regions changes significantly linearly with the state of charge. The inherent difference in charge between cells is equivalent to the difference in ampere-hours. Therefore, the difference in ampere-hours can accurately characterize the difference in ampere-hours of charge caused by the difference in self-discharge of each cell.

[0048] Step S30: Determine whether the power battery has cells with abnormal self-discharge rate based on the difference in ampere-hours.

[0049] When there is only one ampere-hour (Ah) difference value, it can be directly used as a characteristic value of the capacity difference between different cells in the power battery. When there is more than one Ah difference value, the characteristic value of the capacity difference between different cells in the power battery can be determined by combining the more than one Ah difference value. These more than one Ah difference value can be detected separately in different charging and / or discharging states.

[0050] After obtaining the characteristic value, if the characteristic value is greater than the preset threshold, it can be considered that the power battery has an abnormal self-discharge rate; if the characteristic value is less than or equal to the preset threshold, it can be considered that the power battery does not have an abnormal self-discharge rate.

[0051] This embodiment provides a method for monitoring a power battery. When the voltage parameters of the power battery meet preset conditions, indicating that the voltage of the power battery is located in the non-plateau region between different plateau regions, the current of the power battery is integrated over time to obtain the ampere-hour difference value between different cells in the power battery. Based on the ampere-hour difference value, it is determined whether there are cells with abnormal self-discharge rates. Therefore, the detection of whether there are cells with abnormal self-discharge rates in the power battery does not need to wait for the low charge static condition, thereby effectively improving the timeliness of detecting cells with abnormal self-discharge rates and improving the timeliness of battery maintenance.

[0052] In one feasible implementation, the step of determining whether the power battery has cells with abnormal self-discharge rate based on the ampere-hour difference value includes: determining characteristic values ​​of capacity differences of different cells in the power battery based on at least two of the ampere-hour difference values; and determining whether the power battery has cells with abnormal self-discharge rate based on the characteristic values.

[0053] The at least two ampere-hour difference values ​​are detected in different slow charging states. During the process of the power battery entering a slow charging state at least twice, steps S10 and S20 described above can be executed in each slow charging state to obtain the ampere-hour difference value corresponding to each slow charging state. Here, "at least two slow charging states" can refer to at least two consecutive slow charging states or at least two non-consecutive slow charging states. In other implementations, the at least two ampere-hour difference values ​​can be detected in time intervals within a single slow charging state, for example, by executing steps S10 to S20 every preset period within a single slow charging state.

[0054] The average, minimum, maximum, or weighted average of at least two ampere-hour differences can be used as characteristic values ​​here.

[0055] In this embodiment, the initial charge level corresponding to each ampere-hour difference value is obtained. The initial charge level is the charge level of the power battery when it enters the slow charging state corresponding to the ampere-hour difference value. A weight value for the corresponding ampere-hour difference value is determined based on the initial charge level, resulting in at least two weight values. A weighted average is calculated based on the at least two weight values ​​to obtain the feature value. Different initial charges correspond to different weight values. The initial charge level and the corresponding weight value may be negatively correlated; a larger initial charge level results in a smaller corresponding weight value, and vice versa.

[0056] After obtaining the characteristic value, if the characteristic value is greater than the preset threshold, it can be considered that the power battery has an abnormal self-discharge rate; if the characteristic value is less than or equal to the preset threshold, it can be considered that the power battery does not have an abnormal self-discharge rate.

[0057] In this embodiment, using feature values ​​determined by at least two ampere-hour difference values ​​to determine whether there are cells with abnormal self-discharge in the power battery is beneficial to improving the accuracy of self-discharge abnormality identification. Specifically, since the lower the initial charging charge, the smaller the voltage difference between the maximum and minimum cell voltages, the smaller the ampere-hour difference value will be. Therefore, a weighted average of at least two ampere-hour difference values ​​is calculated using the weight value corresponding to the initial charge. This further improves the accuracy of the determined feature values ​​in representing the capacity differences of each cell, thereby further improving the accuracy of determining whether there are cells with abnormal self-discharge in the power battery.

[0058] Based on any of the above embodiments, in the second embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. In addition, the monitoring method for the power battery further includes: When the power battery is in a slow charging state, step S20 is executed after step S10. The slow charging state is also the low current charging condition. When the power battery is in a preset state, after executing step S10, if the voltage parameter meets the preset condition and continues for a preset time, it is determined that the power battery has a cell with an abnormal self-discharge rate; the preset state includes the power battery being in a discharge state and the discharge current being within a set current range.

[0059] Here, the current range is set as a low-current range, and the preset state is a low-current discharge condition. In a low-current discharge condition, the battery continuously discharges at a current far below the rated conventional current, with small current fluctuations and weak polarization. This is the standard operating condition during battery and battery management system testing. When the vehicle is under high voltage and not charging, a current within the set current range can be considered a low-current discharge condition. The set current range can be [-10A, 10A], and can be limited based on the vehicle's current in Sentry Mode / Remote Heating / Cooling / External Discharge modes.

[0060] When the power battery is in a preset state, if the voltage parameters do not meet the preset conditions or the voltage parameters meet the preset conditions but the duration is less than the preset duration, it can be determined that there are no cells with abnormal self-discharge rates in the power battery.

[0061] In particular, when the voltage parameter meets the preset condition and continues for a preset duration under low current discharge conditions, in addition to determining that there are cells with abnormal self-discharge rates in the power battery, it can also identify that there is a fault in the sampling hardware.

[0062] In this embodiment, under low-current charging and discharging conditions, due to the small current amplitude and weak polarization effect, the cell voltage platform characteristics remain intact and stable, the operating condition disturbance is small, and the voltage and current sampling accuracy is high. Different methods are used to identify whether there are cells with abnormal self-discharge rates in the power battery, which helps to further improve the timeliness and accuracy of identifying cells with abnormal self-discharge rates.

[0063] In one feasible implementation, refer to Figure 3 The monitoring method for the power battery further includes: Step S100: When the power battery is in the slow charging state, obtain the initial charge level of the power battery when it enters the slow charging state. Obtaining the initial power level and step S10 described above can be performed simultaneously or sequentially.

[0064] Step S200: When the initial charge is less than the charge threshold, perform the step of integrating the current of the power battery over time to obtain the ampere-hour difference value between different cells in the power battery, provided that the voltage parameter meets the preset conditions.

[0065] The power threshold is set to distinguish whether the difference in ampere-hours in the current slow charging state can accurately characterize the self-discharge difference of different cells in the power battery. Specifically, it can accurately characterize when the initial power is less than the power threshold; otherwise, it cannot accurately characterize.

[0066] The power threshold can be a preset fixed value or a parameter value determined based on the actual charging conditions of the power battery.

[0067] In this embodiment, the above method can avoid errors in the identification of self-discharge anomalies caused by excessive initial charge. Therefore, it ensures that the initial charge is less than the charge threshold before judging whether there is a cell with self-discharge anomaly based on the difference in ampere-hours, which helps to further improve the accuracy of power battery self-discharge anomaly identification.

[0068] In one feasible implementation, the monitoring method for the power battery further includes: acquiring the temperature status parameters of the power battery when it enters the slow charging state and / or the resting time of the power battery before entering the slow charging state; and determining the power threshold based on the temperature status parameters and / or the resting time.

[0069] When entering slow charging mode, the temperature of each cell in the power battery can be detected, and the temperature status parameters are determined based on the detected cell temperatures. In this embodiment, the temperature status parameters include the maximum cell temperature and the minimum cell temperature. The maximum cell temperature is the highest value among all cell temperatures, and the minimum cell temperature is the lowest value among all cell temperatures. In other implementations, the temperature status parameters may also be the average value of all cell temperatures, and so on.

[0070] The resting time is the duration during which the current of the power battery is less than a set current threshold. The set current threshold can be less than the upper limit of the aforementioned set current range. The set current threshold is affected by the accuracy of the current sensor and is also related to the characteristics of the battery cell, and is generally set to 2A. For example, the resting time can be the period from when the vehicle stops moving or the current is 0 when charging is complete until the next power-on to start charging or moving. Alternatively, the resting time can be the duration during which the vehicle is stationary, the sentry mode is activated, or the air conditioner discharges, and the current remains less than the set current threshold until the vehicle enters charging mode.

[0071] Different temperature parameters and / or different resting times correspond to different power thresholds. A pre-established correspondence between temperature parameters and / or resting times and power thresholds can be established, such as through a mapping table or formula. Based on this correspondence, the power threshold corresponding to the current temperature parameters and / or resting time can be determined.

[0072] In this embodiment, the temperature status parameters include the maximum cell temperature and the minimum cell temperature. A cell temperature difference value is determined between the maximum and minimum cell temperatures. The charge threshold is determined based on the cell temperature difference value, the minimum cell temperature, and the resting time. Specifically, when the cell temperature difference value is within a preset temperature range, the resting time is positively correlated with the charge threshold. For example, if the resting time is more than 2 hours, the charge threshold is 50; if the resting time is less than 2 hours, the charge threshold is 40, and so on. The charge threshold corresponding to this resting time may differ depending on the minimum cell temperature.

[0073] In this embodiment, the power threshold is determined based on the temperature state parameters when entering the slow charging state and / or the resting time, which helps to further improve the accuracy of identifying abnormal self-discharge of the power battery.

[0074] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the monitoring method of the power battery in this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0075] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the power battery monitoring method in the above embodiments.

[0076] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0077] The aforementioned computer-readable storage medium may be included in the vehicle or may exist independently and not installed in the vehicle.

[0078] The aforementioned computer-readable storage medium carries one or more programs, which, when executed by a processor, cause the processor to execute the processes in the aforementioned power battery monitoring method embodiments.

[0079] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0080] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described power battery monitoring method. This solves the technical problem of how to improve the timeliness of detecting cells with abnormal self-discharge rates, thereby improving the timeliness of battery maintenance. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the power battery monitoring method provided in the above embodiments, and will not be repeated here.

[0081] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0082] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. Modules described in the embodiments of this application can be implemented in software or hardware. The names of modules do not necessarily limit the specific unit itself. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0083] All actions involving the acquisition of signals, information, or data in this application are carried out in accordance with the relevant data protection laws and policies of the country where the application is located, and with the authorization of the owner of the relevant device.

[0084] The above descriptions are merely some embodiments of this application and do not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the content of this specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application. Therefore, the protection scope of this application should be determined by the scope of the claims.

Claims

1. A method for monitoring a power battery, characterized in that, The monitoring method for the power battery includes: Obtain the voltage parameters of the power battery; When the voltage parameters meet the preset conditions, the current of the power battery is integrated over time to obtain the ampere-hour difference value between different cells in the power battery. The presence of cells with abnormal self-discharge rates in the power battery is determined based on the difference in ampere-hours. The preset condition indicates that the voltage of the power battery is located in the non-platform region between different plateau regions.

2. The monitoring method for a power battery as described in claim 1, characterized in that, The voltage parameters include the minimum cell voltage and the maximum cell voltage of the power battery; The preset conditions include: the minimum cell voltage is greater than the lower limit voltage of the first plateau region of the power battery, the maximum cell voltage is less than the upper limit voltage of the second plateau region of the power battery, and the voltage difference between the maximum cell voltage and the minimum cell voltage is greater than the voltage difference threshold.

3. The monitoring method for a power battery as described in claim 2, characterized in that, The monitoring method for the power battery also includes: The lower limit voltage, the upper limit voltage, and the voltage difference threshold are determined based on the minimum cell temperature of the power battery.

4. The monitoring method for a power battery as described in claim 1, characterized in that, The step of determining whether the power battery has cells with abnormal self-discharge rate based on the difference in ampere-hours includes: The characteristic value of the capacity difference of different cells in the power battery is determined based on at least two of the said ampere-hour difference values; The presence of cells with abnormal self-discharge rates in the power battery is determined based on the aforementioned characteristic values.

5. The monitoring method for a power battery as described in claim 4, characterized in that, The at least two ampere-hour difference values ​​are detected in different slow charging states, and / or, the monitoring method for the power battery further includes: Obtain the initial charge corresponding to each of the ampere-hour difference values, where the initial charge is the charge of the power battery when it enters the slow charging state corresponding to the ampere-hour difference value; Based on the initial power consumption, determine the corresponding weight value of the ampere-hour difference value, and obtain at least two weight values; The step of determining the characteristic value of the capacity difference of different cells in the power battery based on at least two of the ampere-hour difference values ​​includes: The characteristic value is obtained by weighting at least two ampere-hour difference values ​​with at least two weight values.

6. The monitoring method for a power battery as described in any one of claims 1 to 5, characterized in that, The monitoring method for the power battery further includes: When the power battery is in a slow charging state, after obtaining the voltage parameters of the power battery, the step of performing time integration on the current of the power battery under the condition that the voltage parameters meet the preset conditions is executed to obtain the ampere-hour difference value between different cells in the power battery. When the power battery is in a preset state, after acquiring the voltage parameters of the power battery, if the voltage parameters meet the preset conditions and continue for a preset duration, it is determined that the power battery has a cell with an abnormal self-discharge rate; the preset state includes the power battery being in a discharging state and the discharge current being within a set current range.

7. The monitoring method for a power battery as described in claim 6, characterized in that, The set current range is [-10A, 10A]; and / or, the monitoring method for the power battery further includes: When the power battery is in the slow charging state, the initial charge level of the power battery when it enters the slow charging state is obtained; When the initial charge is less than the charge threshold, the step of performing time integration on the current of the power battery to obtain the ampere-hour difference value between different cells in the power battery is executed when the voltage parameter meets the preset conditions.

8. The monitoring method for a power battery as described in claim 7, characterized in that, The monitoring method for the power battery also includes: Obtain the temperature status parameters of the power battery when it enters the slow charging state and / or the resting time of the power battery before it enters the slow charging state; The power threshold is determined based on the temperature status parameter and / or the resting time.

9. The monitoring method for a power battery as described in claim 8, characterized in that, The temperature status parameters include the maximum cell temperature and the minimum cell temperature. The step of determining the charge threshold based on the temperature status parameters and / or the resting time includes: Determine the cell temperature difference between the maximum cell temperature and the minimum cell temperature; The power threshold is determined based on the cell temperature difference, the minimum cell temperature, and the resting time.

10. A vehicle, characterized in that, The vehicle includes a power battery and a battery management device, the power battery and the battery management device being connected, the battery management device including: a memory, a processor and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the power battery monitoring method as described in any one of claims 1 to 9.

11. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the power battery monitoring method as described in any one of claims 1 to 9.

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