Power battery equalization method, power battery equalization equipment and storage medium

Abstract

The invention discloses a power battery equalization method, power battery equalization equipment and a storage medium, and relates to the technical field of batteries, and the method comprises the steps: obtaining the storage duration of the pre-stored equalization duration of each cell in a power battery under the condition that the battery voltage of the power battery after standing is located in a platform area, the pre-stored equalization duration represents an equalization demand of the power battery at a corresponding storage moment; determining a target equalization duration of each battery cell according to a determination mode corresponding to the storage duration; and under the condition that an equalization condition is met, performing equalization operation on the power battery according to the target equalization duration. The invention aims to improve the reliability and efficiency of power battery equalization.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a power battery balancing method, a power battery balancing device, and a storage medium. Background Art

[0002] After the power battery is fully stationary, there is a corresponding relationship between the charge and voltage. When the voltage is in the platform area, it is impossible to obtain an accurate charge value based on this corresponding relationship. Based on this, the method for determining the equalization time when the voltage of the power battery is in the platform area after being stationary is fixed. Generally, the equalization time of the battery is determined by the difference between the voltage of each battery cell and the minimum battery cell in the battery. However, the equalization time determined by this method is not accurate, which easily reduces the reliability and efficiency of battery equalization. Summary of the invention

[0003] The main purpose of the present application is to provide a power battery balancing method, a power battery balancing device and a storage medium, aiming to improve the reliability and efficiency of power battery balancing.

[0004] To achieve the above objectives, the present application proposes a power battery balancing method, the method comprising:

[0005] When the battery voltage of the power battery after being at rest is in a platform area, obtaining a storage duration of a pre-stored balancing duration of each cell in the power battery, wherein the pre-stored balancing duration indicates a balancing requirement of the power battery at a corresponding storage time;

[0006] Determine the target balancing time of each of the battery cells according to the determination method corresponding to the storage time;

[0007] When the balancing condition is met, a balancing operation is performed on the power battery according to the target balancing time.

[0008] In one embodiment, before the step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time, the step further includes:

[0009] When the battery voltage of the power battery after being at rest is in a platform area, determining a reference balancing time length of each of the battery cells according to a voltage difference between the battery voltage of each of the battery cells and a minimum voltage among all the battery cell voltages;

[0010] The step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time comprises:

[0011] When the storage time is longer than the preset time, determining the reference balancing time of the corresponding battery cell as the target balancing time of the battery cell;

[0012] In a case where the stored time is less than or equal to the preset time, a target balancing time of the corresponding battery cell is determined according to the reference balancing time and the pre-stored balancing time.

[0013] In one embodiment, before the step of determining the reference balancing time of each of the battery cells according to the voltage difference between the battery cell voltage of each of the battery cells and the minimum voltage among all the battery cell voltages, the step further includes:

[0014] When the battery voltage of the power battery after being left at rest is in a platform area, a reference voltage difference of the power battery is determined according to the battery temperature difference of the power battery and the sampling accuracy of the single cell voltage of the power battery, and a minimum charge corresponding to the unit voltage of the power battery at different preset temperatures is determined as the balanced charge;

[0015] The step of determining the reference balancing time of each of the battery cells according to the voltage difference between the battery cell voltage of each of the battery cells and the minimum voltage among all the battery cell voltages comprises:

[0016] When the voltage difference is greater than a reference voltage difference of the corresponding battery cell, the target balancing capacity of the corresponding battery cell is determined according to the balancing charge, the rated capacity of the corresponding battery cell and the health status value of the power battery, and the reference balancing time of the corresponding battery cell is determined according to the ratio of the target balancing capacity to the preset balancing current.

[0017] In one embodiment, before the step of determining the reference voltage difference according to the battery temperature difference of the power battery and the sampling accuracy of the single cell voltage of the power battery, the step further includes:

[0018] Determining a minimum temperature and a maximum temperature among the cell temperatures of all the cells in the power battery;

[0019] When the minimum temperature is lower than a preset temperature, determining the temperature difference between the maximum temperature and the minimum temperature as the battery temperature difference;

[0020] When the minimum temperature is greater than or equal to the preset temperature, the preset temperature difference is determined as the battery temperature difference.

[0021] In one embodiment, the step of determining the target equalization duration according to the reference equalization duration and the pre-stored equalization duration includes:

[0022] The maximum value between the reference balancing time length and the pre-stored balancing time length is determined as the target balancing time length.

[0023] In one embodiment, when the battery voltage of the power battery after being left at rest is in the platform area, before the step of obtaining the storage time of the pre-stored equalization time of each battery cell in the power battery, the step further includes:

[0024] When the power is turned off during the power battery balancing process, the current remaining balancing time of the power battery is saved to form the pre-stored balancing time; or,

[0025] When the power battery is powered on during the balancing process, if the continuous sleep time of the power battery is greater than the preset sleep time, 0 is saved as the pre-stored balancing time.

[0026] In one embodiment, before the step of performing a balancing operation on the power battery according to the target balancing time when the power battery meets the balancing condition, the method further includes:

[0027] When the battery voltage is in a non-platform region, a target balancing time of each battery cell is determined according to a charge difference between a charge of each battery cell in the power battery and a minimum charge among all the charges.

[0028] In one embodiment, before the step of determining the target balancing time of each cell according to the charge difference between the charge of each cell in the power battery and the minimum charge among all the charges, the step further includes:

[0029] When the battery voltage is in a non-platform region, determining a charge error according to a minimum temperature of the battery cell temperatures of all the battery cells and a service life of the BMS hardware;

[0030] The step of determining the target balancing time according to the charge difference between the charge of each cell in the power battery and the minimum charge among all the charges comprises:

[0031] Determine a target charge difference for each of the battery cells according to the charge differences and the charge errors;

[0032] Determine the required balancing time of the corresponding battery cell according to the target charge difference and the preset balancing current;

[0033] The required balancing time and the minimum balancing time are determined to determine the target balancing time of the corresponding battery cell.

[0034] In one embodiment, before the step of obtaining the storage duration of the pre-stored balancing duration of each battery cell in the power battery, the step further includes:

[0035] Obtaining a minimum voltage among the cell voltages of the cell and a minimum temperature among the cell temperatures of the cell after the power battery is left stationary;

[0036] Determining a minimum charge corresponding to the minimum voltage based on a target corresponding relationship between a voltage corresponding to the minimum temperature and a charge;

[0037] When the minimum charge is less than a preset charge value, determining that the battery voltage of the power battery after being left at rest is in a non-platform area;

[0038] When the minimum charge is greater than or equal to the preset charge value, it is determined that the battery voltage of the power battery after being left at rest is located in a platform area.

[0039] In one embodiment, after the step of obtaining the minimum voltage among the cell voltages of the cells and the minimum temperature among the cell temperatures of the cells after the power battery is left at rest, the method further includes:

[0040] When the rest time of the power battery is greater than or equal to the reference rest time corresponding to the minimum temperature, the step of determining the minimum charge corresponding to the minimum voltage based on the target corresponding relationship between the voltage and the charge corresponding to the minimum temperature is performed;

[0041] When the rest time of the power battery is less than the reference rest time, the pre-stored balancing time is determined as the target balancing time of the corresponding battery cell.

[0042] In addition, to achieve the above objectives, the present application also proposes a power battery balancing device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the power battery balancing method described above.

[0043] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which 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, the steps of the power battery balancing method described above are implemented.

[0044] One or more technical solutions proposed in the present application have at least the following technical effects: in the case where the battery voltage of the power battery after being left at rest is in the platform area, the target balancing time of each battery cell is no longer determined based on a fixed method, but a corresponding determination method is selected according to the storage time of the pre-stored balancing time to determine the target balancing time of the battery cell during subsequent balancing, wherein the pre-stored balancing time can accurately reflect the balancing demand of the power battery at the moment of storage of the pre-stored balancing time, and the storage time can reflect the change in the battery balancing demand caused by the self-discharge of the battery, so selecting the determination method of the balancing time based on the storage time is conducive to ensuring that the determination of the balancing time can accurately reflect the actual balancing demand of the power battery, improve the accuracy of the determined balancing time, and thus effectively improve the reliability and efficiency of the power battery balancing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0047] Figure 1 A schematic diagram of the device structure of the hardware operating environment involved in the power battery balancing method in the embodiment of the present application;

[0048] Figure 2 A schematic diagram of a flow chart provided for the first embodiment of the power battery balancing method of the present application;

[0049] Figure 3 A flowchart of the second embodiment of the power battery balancing method of the present application is provided.

[0050] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0051] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0052] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0053] The main solution of the embodiment of the present application is: when the battery voltage of the power battery after standing still is in the platform area, the storage time of the pre-stored balancing time of each battery cell in the power battery is obtained, and the pre-stored balancing time indicates the balancing requirement of the power battery at the corresponding storage time; the target balancing time of each battery cell is determined according to the determination method corresponding to the storage time; when the balancing conditions are met, the balancing operation is performed on the power battery according to the target balancing time.

[0054] In this embodiment, for the convenience of description, the following description is made by taking the power battery balancing device as the execution subject.

[0055] In the prior art, the method for determining the equalization time when the voltage of the power battery after being stationary is in the platform area is fixed. Generally, the equalization time of the battery is determined by the difference between the voltage of each battery cell and the minimum battery cell in the battery. However, the equalization time determined by this method is not accurate, which can easily reduce the reliability and efficiency of battery equalization.

[0056] The present application provides the above-mentioned solution, in which the pre-stored balancing time can accurately reflect the balancing demand of the power battery at the storage moment of the pre-stored balancing time, and the storage time can reflect the change in the battery balancing demand caused by the battery self-discharge. Therefore, selecting a method for determining the balancing time based on the storage time is conducive to ensuring that the determination of the balancing time can accurately reflect the actual balancing demand of the power battery, improve the accuracy of the determined balancing time, and thus effectively improve the reliability and efficiency of the power battery balancing.

[0057] The embodiment of the present application provides a power battery balancing device 100 for performing a balancing operation on a power battery 200 .

[0058] In this embodiment, refer to Figure 1 , the power battery equalization device 100 is electrically connected to the power battery 200. The power battery device 100 may be built into the vehicle where the power battery 200 is installed, or may be independently provided from the vehicle where the power battery 200 is installed.

[0059] The power battery balancing device 100 includes: at least one processor 1001; and a memory 1002 connected to the at least one processor 1001 in communication, 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, so that the at least one processor 1001 can execute the power battery balancing method in the following embodiment.

[0060] Reference below Figure 1 , which shows a schematic diagram of the structure of the control device 100 suitable for implementing the embodiment of the present application. The power battery balancing device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 1 The control device 100 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0061] like Figure 1As shown, the control device 100 may include a processor 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to the program stored in the memory 1002, where the program in the memory 1002 may be a program in a read-only memory (ROM) or a program loaded from a storage device to a random access memory (RAM). In the RAM, various programs and data required for the operation of the control device 100 are also stored. The processor 1001 and the memory 1002 (ROM and RAM) are connected to each other through a bus. An input / output (I / O) interface is also connected to the bus. Generally, the following systems can be connected to the I / O interface: input devices such as a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices such as a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices such as a tape, a hard disk, etc.; and communication devices. The communication device can allow the control device 100 to communicate with other devices wirelessly or by wire to exchange data. Although the control device 100 is shown 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 or have instead.

[0062] In particular, according to the embodiments disclosed in the present application, the method flow described in the following embodiments may be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from the memory 1002. When the computer program is executed by the processor 1001, the above functions defined in the power battery balancing method of the embodiment disclosed in the present application are executed.

[0063] The power battery balancing device provided by the present application adopts the power battery balancing method in the following embodiment, which can solve the technical problem of how to improve the reliability and efficiency of power battery balancing. Compared with the prior art, the beneficial effects of the power battery balancing device provided by the present application are the same as the beneficial effects of the power battery balancing method provided in the following embodiment, and other technical features in the power battery balancing device are the same as the features disclosed in the following embodiment method, which will not be repeated here.

[0064] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device capable of realizing the above functions, a power battery balancing device, etc. The following takes a power battery balancing device as an example to illustrate this embodiment and the following embodiments.

[0065] Based on this, the present application embodiment provides a power battery balancing method, referring to Figure 2 , Figure 2 This is a flow chart of the first embodiment of the power battery balancing method of the present application.

[0066] In this embodiment, the power battery balancing method includes steps S10 to S30:

[0067] Step S10, when the battery voltage of the power battery after being left at rest is in a platform area, obtaining a storage duration of a pre-stored balancing duration of each cell in the power battery, wherein the pre-stored balancing duration indicates a balancing requirement of the power battery at a corresponding storage time;

[0068] The resting here means that the power battery has been fully rested, that is, the resting time is greater than or equal to the reference resting time.

[0069] Whether the battery voltage of the power battery after standing still is in the platform area can be determined based on the open circuit voltage of the power battery and a preset voltage interval corresponding to the platform area, or by determining the charge corresponding to the battery voltage and a preset charge interval corresponding to the platform area based on a preset correspondence between voltage and charge.

[0070] The pre-stored balancing duration may include the remaining balancing duration when the balancing was interrupted before the current moment or the balancing duration updated when the updating condition of the balancing duration is met.

[0071] The storage duration is the duration from the initial time when the pre-stored balancing duration is saved to the current time. Different cells may have different pre-stored balancing durations based on their own states.

[0072] In this embodiment, before the step of obtaining the open-circuit voltage of the power battery after being left at rest, it also includes: when the power is turned off during the power battery balancing process, saving the current remaining balancing time of the power battery to form the pre-stored balancing time; or, when the power is turned on during the power battery balancing process, when the continuous dormancy time of the power battery is greater than the preset dormancy time, saving 0 as the pre-stored balancing time. Among them, the remaining balancing time when the power is turned off during the balancing process is used as the pre-stored balancing time, so that the previous balancing effect can be accurately considered in the subsequent balancing process, so as to effectively improve the consistency of each battery cell after subsequent balancing. When the continuous dormancy time is long enough, the pre-stored balancing time is set to 0, then after the battery achieves static balancing through static self-discharge, it can be considered to stop the balancing of the battery cell, which is beneficial to improving the reliability and efficiency of battery balancing.

[0073] Step S20, determining a target balancing time of each of the battery cells according to a determination method corresponding to the storage time;

[0074] Different storage durations correspond to different ways of determining the balancing duration. The determination method may be one of the following: when the cell voltage meets the set conditions, a fixed duration is used as the target balancing duration; a pre-stored balancing duration is used as the target balancing duration; an average of a fixed duration and a pre-stored balancing duration is used as the target balancing duration; a maximum of a fixed duration and a pre-stored balancing duration is used as the target balancing duration, and so on.

[0075] Different battery cells have different corresponding storage durations, so the methods for determining the corresponding target balancing durations may be different.

[0076] Step S30: When the balancing condition is met, performing a balancing operation on the power battery according to the target balancing time.

[0077] In this embodiment, balancing of the power batteries is achieved by inputting balancing current into the power batteries.

[0078] The time starts from the beginning of the balancing operation. The difference between the target balancing time and the timing time is the remaining balancing time. When the remaining balancing time is 0, the balancing operation is stopped; when the remaining balancing time is greater than 0, the balancing operation continues.

[0079] During the execution of the balancing operation, when the vehicle where the power battery is located is powered off, it can be considered that the balancing is interrupted. At this time, the remaining balancing time is saved to form a new pre-stored balancing time.

[0080] After step S30, the process may return to step S10, and the balancing time may be iteratively updated based on the actual usage of the battery.

[0081] The present embodiment provides a power battery balancing method. In this solution, when the battery voltage of the power battery after being left at rest is in a platform area, the target balancing time of each battery cell is no longer determined based on a fixed method, but a corresponding determination method is selected according to the storage time of the pre-stored balancing time to determine the target balancing time of the battery cell during subsequent balancing. The pre-stored balancing time can accurately reflect the balancing demand of the power battery at the moment of storage of the pre-stored balancing time, and the storage time can reflect the change in the battery balancing demand caused by the self-discharge of the battery. Therefore, selecting the determination method of the balancing time based on the storage time is conducive to ensuring that the determination of the balancing time can accurately reflect the actual balancing demand of the power battery, improve the accuracy of the determined balancing time, and thus effectively improve the reliability and efficiency of the power battery balancing.

[0082] In a feasible implementation manner, before the step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time, it also includes: when the battery voltage of the power battery after standing still is in the platform area, determining the reference balancing time of each of the battery cells according to the voltage difference between the battery voltage of each of the battery cells and the minimum voltage of all the battery cell voltages.

[0083] The cell voltage is the open circuit voltage of each cell detected after the power battery is left at rest.

[0084] The reference equalization time may be positively correlated with the corresponding voltage difference.

[0085] In this embodiment, the reference balancing time of each battery cell is determined according to the voltage difference of the corresponding battery cell. In other embodiments, the reference balancing time of each battery cell can also be allocated in proportion according to the proportional relationship between the voltage differences of all battery cells.

[0086] Based on the reference balancing time obtained above, the step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time includes:

[0087] When the storage time is longer than the preset time, determining the reference balancing time of the corresponding battery cell as the target balancing time of the battery cell;

[0088] In a case where the stored time is less than or equal to the preset time, a target balancing time of the corresponding battery cell is determined according to the reference balancing time and the pre-stored balancing time.

[0089] The preset duration is a critical value for distinguishing whether the equalization demand of the target battery before the current moment is completed by self-discharge. The preset duration can be a preset fixed duration, or a duration determined according to a pre-stored equalization duration.

[0090] In this embodiment, the maximum value between the reference balancing time length and the pre-stored balancing time length is determined as the target balancing time length.

[0091] In this embodiment, the above method is helpful to improve the accuracy of the analysis of the current balancing demand of the power battery, thereby improving the accuracy of the determined target balancing time, and further improving the balancing reliability and efficiency of the power battery.

[0092] In other embodiments, the average of the reference balancing duration and the pre-stored balancing duration may be determined as the target balancing duration. Alternatively, a first weight corresponding to the reference balancing duration and a second weight corresponding to the pre-stored balancing duration are determined according to the stored duration, and the reference balancing duration and the pre-stored balancing duration are weighted averaged according to the first weight and the second weight to obtain the target balancing duration.

[0093] In a feasible implementation manner, the reference voltage difference of the power battery is determined according to the battery temperature difference of the power battery and the sampling accuracy of the single cell voltage of the power battery, and the minimum charge corresponding to the unit voltage of the power battery at different preset temperatures is determined as the balancing charge; the step of determining the reference balancing time of each battery cell according to the voltage difference between the battery cell voltage of each battery cell and the minimum voltage among all the battery cell voltages includes: when the voltage difference is greater than the reference voltage difference of the corresponding battery cell, determining the target balancing capacity of the corresponding battery cell according to the balancing charge, the rated capacity of the corresponding battery cell and the health status value of the power battery, and determining the reference balancing time of the corresponding battery cell according to the ratio of the target balancing capacity to the preset balancing current.

[0094] The battery temperature difference is determined according to the temperature difference between the battery cell temperatures of each battery cell in the power battery. In this embodiment, the minimum temperature and the maximum temperature of the battery cell temperatures of all the battery cells in the power battery are determined; when the minimum temperature is less than the preset temperature, the temperature difference between the maximum temperature and the minimum temperature is determined as the battery temperature difference; when the minimum temperature is greater than or equal to the preset temperature, the preset temperature difference is determined as the battery temperature difference. Based on this, it can avoid that the battery balancing time is too long due to the minimum temperature being too low, which is conducive to improving reliability and balancing efficiency.

[0095] The sampling accuracy can be obtained from the information provided by the BMS supplier. The sampling accuracy is linearly positively correlated with the service life of the BMS (Battery Management System) hardware.

[0096] Different battery temperature differences and different sampling accuracies correspond to different reference pressure differences. In this embodiment, the reference pressure difference is determined by the battery temperature difference, the reference pressure difference is positively correlated with the battery temperature difference, and the sum of the reference pressure difference and the sampling accuracy is used as the reference pressure difference.

[0097] The corresponding relationship between the minimum power of the power battery corresponding to different preset temperatures and unit voltages is obtained. The corresponding relationship may include a relational expression or a mapping table, and the minimum charge in the relationship is used as the balanced charge here.

[0098] The preset balancing current is the balancing current output by the balancing device supported by the BMS hardware.

[0099] In this embodiment, the target balancing capacity is obtained by multiplying the balancing charge, the rated capacity of the battery cell, and the power battery health status (SOH), and the ratio of the target balancing capacity to the preset balancing current is used as the corresponding reference balancing time. In other embodiments, the reference balancing time can also be obtained by correcting the comparison value based on the preset coefficient.

[0100] In this embodiment, through the above method, an accurate reference balancing time can be determined based on the balancing demand reflected by the current state of the power battery, which is conducive to further improving the accuracy of the subsequent target balancing time and achieving further improvement in the balancing reliability and efficiency of the power battery.

[0101] Among them, when the voltage difference is less than the reference voltage difference of the corresponding battery cell, the set balancing time can be used as the reference balancing time.

[0102] In other embodiments, a relationship between the voltage difference and the reference equalization time may be directly established, and the corresponding reference equalization time may be calculated by substituting the voltage difference into the relationship.

[0103] Based on any of the above embodiments, in the second embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 3 Before step S30, the method further includes step S100:

[0104] Step S100 , when the battery voltage is in a non-platform region, determining a target balancing time of each battery cell according to a charge difference between the charge of each battery cell in the power battery and a minimum charge among all the charges.

[0105] Different charge differences correspond to different target balancing time lengths. In this embodiment, the target balancing time length is positively correlated with the charge difference.

[0106] In this embodiment, before the step of determining the target balancing time according to the charge difference between the charge of each cell in the power battery and the minimum charge among all the charges, it also includes: determining the charge error according to the minimum temperature among the cell temperatures of all the cells and the service life of the BMS hardware. Based on this, step S100 includes: determining the target charge difference of each cell according to the charge difference and the charge error; determining the required balancing time of the corresponding cell according to the target charge difference and the preset balancing current; determining the maximum value of the required balancing time and the minimum balancing time as the target balancing time of the corresponding cell.

[0107] Among them, before step S100, the first correspondence between the cell temperature, cell charge and open circuit voltage of the power battery, the initial sampling accuracy of the cell voltage, the full life sampling accuracy of the cell voltage and the service life of the BMS hardware can be obtained from the supplier of the BMS. Based on the above sampling accuracy, the second correspondence between the service life of the BMS hardware and the sampling accuracy of the cell voltage can be obtained. In combination with the initial sampling accuracy, the full life sampling accuracy, and the first correspondence, the correspondence between the temperature and the charge error can be obtained. In combination with the first correspondence and the second correspondence, the third correspondence between the temperature, the service life of the BMS hardware and the charge error can be obtained. The third correspondence may include a relational expression, a mapping table, and the like. The sampling accuracy here is linearly positively correlated with the service life of the BMS (Battery Management System) hardware. Based on the third correspondence, the charge error corresponding to the current minimum temperature and the service life of the BMS hardware can be determined.

[0108] In this embodiment, the difference between the charge difference and the charge error is the corresponding target charge difference.

[0109] The target capacity required for equalization of the corresponding battery can be determined based on the target charge difference, the rated capacity of the corresponding battery cell, and the health status value of the power battery, and the ratio of the target capacity to the preset equalization current is used as the required equalization time of the corresponding battery cell. Among them, the product of the target charge difference, the rated capacity of the battery cell and the health status value is the corresponding target capacity.

[0110] In this embodiment, the minimum balancing time is 0. In other embodiments, the minimum balancing time may also be set to other values ​​according to actual needs.

[0111] In this embodiment, the maximum duration of the demand balancing duration and the minimum balancing duration is the corresponding target balancing duration. In other embodiments, the average of the demand balancing duration and the minimum balancing duration can also be used as the target balancing duration.

[0112] In this embodiment, in the non-platform area, based on the precise correspondence between voltage and charge, the target balancing time of the battery cell is determined based on the charge difference, which is conducive to improving the accuracy of the balancing time. Among them, the required balancing time of each battery cell is further analyzed in combination with the minimum battery cell temperature and the charge error corresponding to the BMS hardware service life, and the maximum value of the required balancing time and the minimum balancing time is used as the target balancing time of the corresponding battery cell, which is conducive to further improving the reliability of battery balancing.

[0113] Based on any of the above embodiments, in this embodiment, before the step of obtaining the storage time of the pre-stored equalization time of each battery cell in the power battery, it also includes: obtaining the minimum voltage among the battery cell voltages and the minimum temperature among the battery cell temperatures of the battery cells after the power battery is at rest; determining the minimum charge corresponding to the minimum voltage based on the target corresponding relationship between the voltage corresponding to the minimum temperature and the charge; when the minimum charge is less than a preset charge value, determining that the battery voltage of the power battery after standing still is located in a non-platform area; when the minimum charge is greater than or equal to the preset charge value, determining that the battery voltage of the power battery after standing still is located in a platform area.

[0114] Different minimum temperatures correspond to different target corresponding relationships, and the target corresponding relationship may include a quantitative relationship or a mapping table, etc. The corresponding minimum charge can be obtained by looking up the minimum voltage in a table or substituting it into the quantitative relationship.

[0115] In this embodiment, the current minimum charge of all battery cells is determined in combination with the temperature and voltage, and based on the minimum charge, it is determined whether the battery voltage of the power battery is in the platform area, and based on the determination result, a corresponding method is selected to determine the target balancing time, which is conducive to further improving the balancing reliability and efficiency.

[0116] In a feasible implementation manner, after the step of obtaining the minimum voltage among the cell voltages of the cell and the minimum temperature among the cell temperatures of the cell after the power battery is left at rest, the step further includes:

[0117] When the rest time of the power battery is greater than or equal to the reference rest time corresponding to the minimum temperature, the step of determining the minimum charge corresponding to the minimum voltage based on the target corresponding relationship between the voltage and the charge corresponding to the minimum temperature is performed;

[0118] When the rest time of the power battery is less than the reference rest time, the pre-stored balancing time is determined as the target balancing time of the corresponding battery cell.

[0119] The reference resting time is the minimum time required for the power battery to be fully rested. The above-mentioned preset sleep time may be greater than or equal to the reference resting time.

[0120] Different minimum temperatures correspond to different reference resting times, which can be obtained by looking up the minimum temperature in a table or substituting it into a preset relationship. A resting time greater than or equal to the reference resting time indicates that the power battery has been fully rested; a resting time less than the reference resting time indicates that the power battery has not been fully rested.

[0121] In this embodiment, different methods are used to determine the target balancing time of the battery cell based on whether the power battery is sufficiently static, thereby further improving the reliability and efficiency of battery balancing. If the battery is not sufficiently static, it means that the self-discharge during the static process fails to balance the unbalanced charge at the storage time of the pre-stored balancing time. Therefore, taking the pre-stored balancing time as the target balancing time is conducive to effectively improving the reliability of battery balancing.

[0122] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the power battery balancing method of the present application. More simple transformations based on this technical concept are all within the protection scope of the present application.

[0123] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the power battery balancing method in the above-mentioned embodiment.

[0124] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. 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 combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0125] The computer-readable storage medium may be included in the power battery balancing device; or may exist independently without being assembled into the power battery balancing device.

[0126] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the power battery balancing device, the power battery balancing device performs the following process: when the battery voltage of the power battery after being at rest is in the platform area, the storage duration of the pre-stored balancing duration of each battery cell in the power battery is obtained, and the pre-stored balancing duration indicates the balancing requirement of the power battery at the corresponding storage time; the target balancing duration of each battery cell is determined according to the determination method corresponding to the storage duration; and when the balancing condition is met, the balancing operation is performed on the power battery according to the target balancing duration.

[0127] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0128] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned power battery balancing method, and can solve the technical problem of how to improve the reliability and efficiency of power battery balancing. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the power battery balancing method provided in the above-mentioned embodiment, and will not be repeated here.

[0129] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0130] It should be understood that the various parts disclosed in the present application can be implemented by hardware, software, firmware or a combination thereof. The modules described in the embodiments of the present application can be implemented by software or by hardware. The name of the module does not constitute a limitation on the unit itself under certain circumstances. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0131] The above description is only part of the embodiments of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made by using the contents of the present application specification and drawings under the technical concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A power battery balancing method, characterized in that: The method comprises: When the battery voltage of the power battery after being left at rest is in a platform area, obtaining a storage duration of a pre-stored balancing duration of each cell in the power battery, wherein the pre-stored balancing duration indicates a balancing requirement of the power battery at a corresponding storage time; Determine the target balancing time of each of the battery cells according to the determination method corresponding to the storage time; When the balancing condition is met, a balancing operation is performed on the power battery according to the target balancing time.

2. The method according to claim 1, characterized in that Before the step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time, the method further includes: When the battery voltage of the power battery after being left at rest is in a platform area, determining a reference balancing time length of each of the battery cells according to a voltage difference between the battery cell voltage of each of the battery cells and a minimum voltage among all the battery cell voltages; The step of determining the target balancing time of each of the battery cells according to the determination method corresponding to the storage time comprises: When the storage time is longer than the preset time, determining the reference balancing time of the corresponding battery cell as the target balancing time of the battery cell; In a case where the stored time is less than or equal to the preset time, a target balancing time of the corresponding battery cell is determined according to the reference balancing time and the pre-stored balancing time.

3. The method according to claim 2, characterized in that Before the step of determining the reference balancing time of each of the battery cells according to the voltage difference between the battery cell voltage of each of the battery cells and the minimum voltage among all the battery cell voltages, the step further includes: When the battery voltage of the power battery after being left at rest is in a platform area, a reference voltage difference of the power battery is determined according to the battery temperature difference of the power battery and the sampling accuracy of the single cell voltage of the power battery, and a minimum charge corresponding to the unit voltage of the power battery at different preset temperatures is determined as the balanced charge; The step of determining the reference balancing time of each of the battery cells according to the voltage difference between the battery cell voltage of each of the battery cells and the minimum voltage among all the battery cell voltages comprises: When the voltage difference is greater than a reference voltage difference of the corresponding battery cell, the target balancing capacity of the corresponding battery cell is determined according to the balancing charge, the rated capacity of the corresponding battery cell and the health status value of the power battery, and the reference balancing time of the corresponding battery cell is determined according to the ratio of the target balancing capacity to the preset balancing current.

4. The method according to claim 3, characterized in that Before the step of determining the reference voltage difference according to the battery temperature difference of the power battery and the sampling accuracy of the single cell voltage of the power battery, the method further includes: Determining a minimum temperature and a maximum temperature among the cell temperatures of all the cells in the power battery; When the minimum temperature is lower than a preset temperature, determining the temperature difference between the maximum temperature and the minimum temperature as the battery temperature difference; When the minimum temperature is greater than or equal to the preset temperature, the preset temperature difference is determined as the battery temperature difference.

5. The method according to claim 2, characterized in that The step of determining the target equalization duration according to the reference equalization duration and the pre-stored equalization duration comprises: The maximum value between the reference balancing time length and the pre-stored balancing time length is determined as the target balancing time length.

6. The method according to claim 1, characterized in that Before the step of obtaining the storage time of the pre-stored equalization time of each cell in the power battery when the battery voltage of the power battery after being left at rest is in the platform area, the step further includes: When the power is turned off during the power battery balancing process, the current remaining balancing time of the power battery is saved to form the pre-stored balancing time; or, When the power battery is powered on during the balancing process, if the continuous sleep time of the power battery is greater than the preset sleep time, 0 is saved as the pre-stored balancing time.

7. The method according to claim 1, characterized in that Before the step of performing a balancing operation on the power battery according to the target balancing time when the power battery meets the balancing condition, the method further includes: When the battery voltage is in a non-platform region, a target balancing time of each battery cell is determined according to a charge difference between a charge of each battery cell in the power battery and a minimum charge among all the charges.

8. The method according to claim 7, characterized in that Before the step of determining the target balancing time of each cell according to the charge difference between the charge of each cell in the power battery and the minimum charge among all the charges, the step further includes: When the battery voltage is in a non-platform region, determining a charge error according to a minimum temperature of the battery cell temperatures of all the battery cells and a service life of the BMS hardware; The step of determining the target balancing time according to the charge difference between the charge of each cell in the power battery and the minimum charge among all the charges comprises: Determine a target charge difference for each of the battery cells according to the charge differences and the charge errors; Determine the required balancing time of the corresponding battery cell according to the target charge difference and the preset balancing current; The required balancing time and the minimum balancing time are determined to determine the target balancing time of the corresponding battery cell.

9. The method according to any one of claims 1 to 8, characterized in that Before the step of obtaining the storage duration of the pre-stored balancing duration of each battery cell in the power battery, the method further includes: Obtaining a minimum voltage among the cell voltages of the cell and a minimum temperature among the cell temperatures of the cell after the power battery is left stationary; Determining a minimum charge corresponding to the minimum voltage based on a target corresponding relationship between a voltage corresponding to the minimum temperature and a charge; When the minimum charge is less than a preset charge value, determining that the battery voltage of the power battery after being left at rest is in a non-platform area; When the minimum power is greater than or equal to the preset charge value, it is determined that the battery voltage of the power battery after being left at rest is located in a platform area.

10. The method according to claim 9, characterized in that After the step of obtaining the minimum voltage among the cell voltages of the cells and the minimum temperature among the cell temperatures of the cells after the power battery is left stationary, the method further includes: When the rest time of the power battery is greater than or equal to the reference rest time corresponding to the minimum temperature, the step of determining the minimum charge corresponding to the minimum voltage based on the target corresponding relationship between the voltage and the charge corresponding to the minimum temperature is performed; When the rest time of the power battery is less than the reference rest time, the pre-stored balancing time is determined as the target balancing time of the corresponding battery cell.

11. A power battery equalization device, characterized in that: The power battery balancing device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the power battery balancing method according to any one of claims 1 to 10.

12. 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, the steps of the power battery balancing method according to any one of claims 1 to 10 are implemented.

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