Method and device for determining state of charge of energy storage system and energy storage system

Abstract

The present application discloses a method, device and energy storage system for determining the state of charge of an energy storage system, and belongs to the field of energy storage systems. The energy storage system includes at least one battery pack, and each of the battery packs includes at least one battery cell. The method for determining the state of charge of the energy storage system includes: obtaining the electrical signal interval of each of the battery cells; the electrical signal interval includes: a low-end non-platform area, a platform area and a charging terminal; based on the electrical signal interval corresponding to each of the battery cells, the electrical signal of each of the battery cells, the temperature of each of the battery cells and the theoretical state of charge of each of the battery cells, determine the target state of charge of each of the battery cells. The method for determining the state of charge of the energy storage system of the present application improves the precision and accuracy of the determined target state of charge, improves the performance of the battery, and improves the user experience.

Description

Technical Field

[0001] The present application relates to the field of energy storage systems, and in particular to a method and device for determining a state of charge of an energy storage system, and an energy storage system. Background Art

[0002] As an internal parameter of the battery, the state of charge cannot be directly and accurately measured, and can only be estimated. In the related art, the ampere-hour integration method is mainly used to integrate the battery throughput current value with the battery capacity to obtain the change value of the state of charge. However, due to the error of the current sensor in the above method, as the battery is charged and discharged for a long time, the cumulative error will further increase, causing the error between the estimated state of charge value and the actual value to gradually increase, affecting the battery performance and the user experience. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a method, device and energy storage system for determining the state of charge of an energy storage system, which reduces the error between the estimated state of charge and the actual value, improves the precision and accuracy of the determined target state of charge, improves the performance of the battery, and improves the user experience.

[0004] In a first aspect, the present application provides a method for determining a state of charge of an energy storage system, wherein the energy storage system includes at least one battery pack, each of the battery packs includes at least one battery cell, and the method includes:

[0005] Acquire the electrical signal interval of each battery cell; the electrical signal interval includes: a low-end non-platform area, a platform area, and a charging terminal;

[0006] The target state of charge of each battery cell is determined based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell.

[0007] According to the method for determining the state of charge of the energy storage system of the present application, the electrical signal interval of each battery cell is obtained to determine the actual electrical signal interval of each battery cell, the actual usage scenario of each battery cell is determined, and based on the actual usage scenario, different methods are used to determine the target state of charge of the target battery cell, reduce the error between the estimated state of charge and the actual value, improve the precision and accuracy of the determined target state of charge, improve the battery performance, and improve the user experience.

[0008] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of each battery cell is determined based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell, including:

[0009] Based on the electrical signal of the target battery cell in each of the battery cells and the temperature of the target battery cell, searching an open circuit voltage-state of charge table to obtain a first state of charge of the target battery cell under the electrical signal and the temperature; the open circuit voltage-state of charge table is predetermined;

[0010] The target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell.

[0011] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell, including:

[0012] When all of the electrical signal intervals are in the low-end non-platform region, correcting the theoretical state of charge of the target battery cell to the first state of charge of the target battery cell;

[0013] Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

[0014] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell, including:

[0015] When at least part of the electrical signal interval is the low-end non-platform area, and the remaining part of the electrical signal interval except the at least part is the platform area, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge and the low-end inflection point state of charge; the low-end inflection point state of charge is the state of charge corresponding to the inflection point of the low-end non-platform area of ​​the open circuit voltage-state of charge curve corresponding to the open circuit voltage-state of charge table at the target temperature.

[0016] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge and the low-end inflection point state of charge, including:

[0017] Acquiring difference information between the theoretical state of charge and the first state of charge;

[0018] The target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge.

[0019] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge, the difference information and the low-end inflection point state of charge, including:

[0020] When the first state of charge is greater than the theoretical state of charge, the difference information is greater than a first difference threshold, and the theoretical state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge corresponding to the target battery cell to the low-end inflection point state of charge;

[0021] Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

[0022] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge, the difference information and the low-end inflection point state of charge, including:

[0023] In the case where the first state of charge is not greater than the theoretical state of charge, the difference information is greater than a second difference threshold, and the first state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge to the first state of charge;

[0024] Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

[0025] According to the method for determining the state of charge of the energy storage system of the present application, the target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell, including:

[0026] In the case where the battery pack where the target battery cell is located is not fully charged, the electrical signal interval of the target battery cell is the charging terminal, and the theoretical state of charge is less than the state of charge at the charging terminal inflection point; the state of charge at the charging terminal inflection point is the state of charge corresponding to the inflection point of the charging terminal of the charging curve of the target battery cell at the target temperature;

[0027] Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

[0028] According to the method for determining the state of charge of the energy storage system of the present application, the electrical signal interval is determined based on the following steps:

[0029] When the electrical signal collected from the target battery cell among the battery cells after being left at rest for a target time is less than a first electrical signal threshold, determining the electrical signal interval of the target battery cell as the low-end non-platform area;

[0030] When the electrical signal of a target battery cell among the battery cells collected after being left at rest for a target time is not less than a first electrical signal threshold, determining the electrical signal interval of the target battery cell as the platform area;

[0031] When the charging current of a target battery cell among the battery cells is less than a first current threshold and the electrical signal collected by the target battery cell during charging is greater than a second electrical signal threshold, the electrical signal interval of the target battery cell is determined as the charging end.

[0032] The method for determining the state of charge of the energy storage system according to the present application also includes:

[0033] Based on at least one of the battery health information and the number of charge and discharge cycles of each of the battery cells, an open circuit voltage-state of charge table is updated.

[0034] According to the method for determining the state of charge of the energy storage system of the present application, the updating of the open circuit voltage-state of charge table based on at least one of the battery health information and the number of charge and discharge cycles of each of the battery cells includes:

[0035] When at least one of the battery health information is less than a target health threshold and the number of charge and discharge cycles is greater than a target cycle threshold, and the electrical signal interval of a target battery cell among the battery cells is the low-end non-platform area and the theoretical state of charge is corrected, obtaining a target temperature corresponding to the target battery cell correcting the theoretical state of charge, an electrical signal corresponding to the target battery cell correcting the theoretical state of charge, and a first state of charge corresponding to the target battery cell correcting the theoretical state of charge;

[0036] The open circuit voltage-state of charge table is updated based on the target temperature, the electrical signal, and the first state of charge.

[0037] According to the method for determining the state of charge of the energy storage system of the present application, the updating of the open circuit voltage-state of charge table based on the target temperature, the electrical signal and the first state of charge includes:

[0038] When the first state of charge is less than the theoretical state of charge of the target battery cell and the battery pack where the target battery cell is located is fully charged within the target number of charge and discharge cycles, the second state of charge of the target battery cell at the target temperature is determined based on the maximum state of charge, the theoretical state of charge of the target battery cell at a collection moment before the battery pack where the target battery cell is located is fully charged, and the first state of charge; the maximum state of charge is the state of charge of the target battery cell when it is fully charged;

[0039] The open circuit voltage-state of charge table is updated based on the second state of charge of the target battery cell at the target temperature.

[0040] According to the method for determining the state of charge of the energy storage system of the present application, the updating of the open circuit voltage-state of charge table based on the target temperature, the electrical signal and the first state of charge includes:

[0041] When the first state of charge is not less than the theoretical state of charge of the target battery cell, and the difference between the state of charge of the battery pack where the target battery cell is located at the current collection time and the full charge is within a target range, the charging capacity accumulation information is obtained based on the state of charge threshold;

[0042] determining a third state of charge of the target battery cell at the target temperature based on the first state of charge, the charging capacity accumulation information, and a maximum discharge capacity of the target battery cell at the target temperature;

[0043] The open circuit voltage-state of charge table is updated based on a third state of charge of the target battery cell at the target temperature.

[0044] According to the method for determining the state of charge of the energy storage system of the present application, after updating the open circuit voltage-state of charge table based on at least one of the battery health information and the number of charge and discharge cycles of each battery cell, the method further includes:

[0045] Obtaining an open circuit voltage-state of charge curve corresponding to the updated open circuit voltage-state of charge table;

[0046] At least one of the low-end inflection point state of charge and the charging terminal inflection point state of charge is updated based on the open circuit voltage-state of charge curve.

[0047] In a second aspect, the present application provides a device for determining a state of charge of an energy storage system, wherein the energy storage system includes at least one battery pack, each of which includes at least one battery cell, and the device includes:

[0048] A first processing module is used to obtain the electrical signal interval of each battery cell; the electrical signal interval includes: a low-end non-platform area, a platform area and a charging terminal;

[0049] The second processing module is used to determine the target state of charge of each battery cell based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell.

[0050] According to the device for determining the state of charge of the energy storage system of the present application, by acquiring the electrical signal interval of each battery cell, the electrical signal interval in which each battery cell is actually located is determined, the actual usage scenario of each battery cell is determined, and based on the actual usage scenario, different methods are adopted to determine the target state of charge of the target battery cell, thereby reducing the error between the estimated state of charge and the actual value, improving the precision and accuracy of the determined target state of charge, improving the battery performance, and improving the user experience.

[0051] In a third aspect, the present application provides an energy storage system, comprising:

[0052] at least one battery pack, each of the battery packs comprising at least one battery cell;

[0053] The energy storage system determines the state of charge based on the method for determining the state of charge of the energy storage system as described in the first aspect.

[0054] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for determining the state of charge of the energy storage system as described in the first aspect above is implemented.

[0055] In a fifth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for determining the state of charge of the energy storage system as described in the first aspect above is implemented.

[0056] In a sixth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the method for determining the state of charge of an energy storage system as described in the first aspect above.

[0057] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0058] By obtaining the electrical signal range of each battery cell, determining the actual electrical signal range of each battery cell, determining the actual usage scenario of each battery cell, and based on the actual usage scenario, using different methods to determine the target state of charge of the target battery cell, reducing the error between the estimated state of charge and the actual value, improving the precision and accuracy of the determined target state of charge, improving the battery performance, and improving the user experience.

[0059] Furthermore, by looking up the open circuit voltage-state of charge table, the first state of charge of the target battery cell at the current collection moment is obtained, and based on the distribution of the electrical signal interval of the battery pack where the target battery cell is located, the first state of charge and the theoretical state of charge, different judgment conditions are selected to determine whether the theoretical state of charge needs to be corrected, and if correction is required, the theoretical state of charge is corrected through different correction methods in different usage scenarios, and the correction method is flexibly selected to improve the accuracy of the correction result, thereby improving the accuracy of the determined target state of charge.

[0060] Furthermore, whether the battery cell is aged is determined through the battery health information and the number of charge and discharge cycles of the battery cell, and an effective judgment is made based on the actual use of the battery cell to determine whether to update the open circuit voltage-state of charge table. In the case of aging of the battery cell, the open circuit voltage-state of charge table is updated in time to ensure the availability of the data in the open circuit voltage-state of charge table. In addition, when the battery is normal, no update is required to avoid invalid updates.

[0061] Furthermore, by acquiring one or more of the electrical signal and the charging current of the target battery cell, the electrical signal interval of the target battery cell can be effectively determined, and the determination logic is simple and easy to operate.

[0062] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0064] Figure 1 It is one of the flow charts of the method for determining the state of charge of the energy storage system provided in the embodiment of the present application;

[0065] Figure 2It is one of the principle schematic diagrams of the method for determining the state of charge of the energy storage system provided in the embodiment of the present application;

[0066] Figure 3 This is the second principle schematic diagram of the method for determining the state of charge of the energy storage system provided in the embodiment of the present application;

[0067] Figure 4 is a structural schematic diagram of a device for determining a state of charge of an energy storage system provided in an embodiment of the present application;

[0068] Figure 5 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0070] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0071] In conjunction with the accompanying drawings, the state of charge determination method of the energy storage system, the state of charge determination device of the energy storage system, the energy storage system, the electronic device and the readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0072] The method for determining the state of charge of the energy storage system may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0073] The terminal includes but is not limited to portable communication devices such as mobile phones or tablet computers. It should also be understood that in some embodiments, the terminal may not be a portable communication device, but a desktop computer.

[0074] In the following various embodiments, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, a mouse and a joystick.

[0075] The method for determining the state of charge of an energy storage system provided in an embodiment of the present application may be executed by the energy storage system, or may be a state of charge determination device of the energy storage system disposed on the energy storage system, or may be a server electrically connected (wired or wirelessly connected) to the energy storage system, or may be a user terminal communicatively connected to the energy storage system, including but not limited to a mobile terminal and a non-mobile terminal.

[0076] like Figure 1 As shown, the method for determining the state of charge of the energy storage system includes: step 110 and step 120.

[0077] The energy storage system includes at least one battery pack.

[0078] Each battery pack includes at least one battery cell.

[0079] Step 110, obtaining the electrical signal interval of each battery cell;

[0080] In this step, the electrical signal interval is the interval in which the voltage of the battery cell is located, that is, the voltage interval.

[0081] The electrical signal range includes: low-end non-platform area, platform area and charging terminal.

[0082] The low-end non-platform area is a range where the voltage of the battery cells is relatively low.

[0083] The platform area is a stage where the voltage change of the battery cell is relatively stable.

[0084] The end of charging is the stage when the battery cell is close to being fully charged and the voltage is close to the charging cut-off voltage.

[0085] In the actual implementation process, the electrical signal interval of each battery cell can be determined by collecting the electrical signal of each battery cell.

[0086] In some embodiments, based on the slopes of the open circuit voltage-state of charge curves of the battery cells at different temperatures, the curves of the battery cells during the static state can be divided into a low-end non-platform area and a platform area.

[0087] In some embodiments, the charging terminal is determined based on the change in slope of the charging curve of the battery cell at different temperatures.

[0088] In some embodiments, the electrical signal interval may be determined based on the following steps:

[0089] When the electrical signal collected from the target battery cell among the battery cells after being left at rest for the target time is less than the first electrical signal threshold, determining the electrical signal interval of the target battery cell as a low-end non-platform area;

[0090] When the electrical signal of the target battery cell among the battery cells collected after being left at rest for the target time is not less than the first electrical signal threshold, determining the electrical signal interval of the target battery cell as a platform area;

[0091] When the charging current of the target battery cell among the battery cells is less than the first current threshold and the electrical signal collected by the target battery cell during charging is greater than the second electrical signal threshold, the electrical signal interval of the target battery cell is determined to be the charging end.

[0092] In this embodiment, the target battery cell is any battery cell among the plurality of battery cells.

[0093] The target duration is a preset duration.

[0094] The specific value of the target duration can be determined based on actual conditions and is not limited in this application.

[0095] The electrical signal is used to characterize the characteristics of the target battery cell at the current acquisition moment.

[0096] The electrical signal may be a voltage, current, power or other signal.

[0097] The first electrical signal threshold is a preset value for determining the target battery cell electrical signal interval based on the electrical signal.

[0098] The charging current is the current during the charging process of the battery cell.

[0099] The first current threshold is a preset value for determining the target battery cell electrical signal interval based on the charging current.

[0100] The first current threshold can be determined based on actual conditions and is not limited in this application.

[0101] In the actual implementation process, taking the electrical signal as voltage as an example, the electrical signal interval of the battery cell can be determined based on the following steps.

[0102] After the battery cell is left stationary for a target period of time, the voltage of the target battery cell is collected and compared with the first electrical signal threshold. When the voltage is less than the first electrical signal threshold, it can be determined that the electrical signal interval of the battery cell is a low-end non-platform area. When the voltage is not less than the first electrical signal threshold, it can be determined that the electrical signal interval of the battery cell is a platform area.

[0103] During the charging process of the battery cell, the charging current and voltage of the target battery cell are collected. When the charging current is less than the first current threshold and the voltage is greater than the second electrical signal threshold, the electrical signal interval of the target battery cell can be determined as the charging end.

[0104] According to the method for determining the state of charge of the energy storage system provided in the embodiment of the present application, by acquiring the electrical signal of the target battery cell and one or more of the charging current, the electrical signal interval of the target battery cell can be effectively determined. The determination logic is simple and easy to operate.

[0105] Step 120 : determining a target state of charge of each battery cell based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell, and the theoretical state of charge of each battery cell.

[0106] In this step, the theoretical state of charge is the state of charge of the battery cell calculated based on the ampere-hour integral. The theoretical state of charge can be expressed as CellSoc n .

[0107] The target state of charge is the actual state of charge of the battery cell determined based on the theoretical state of charge calculated based on the ampere-hour integration.

[0108] It is understandable that the state of charge of a battery cell cannot be directly and accurately measured, but the state of charge of the battery cell can be obtained by estimating the state of charge.

[0109] In some embodiments, the theoretical state of charge calculated by ampere-hour integration is determined as the target state of charge.

[0110] In the actual implementation process, as the battery cells are charged and discharged continuously for a long time, the cumulative error of the theoretical and actual state of charge calculated by the ampere-hour integration will gradually increase, and the actual state of charge will slowly deviate from the actual value. At this time, the theoretical state of charge can be corrected based on the actual situation of the theoretical state of charge, or the theoretical state of charge can be kept unchanged to determine the target state of charge.

[0111] During the actual execution process, the actual situation of the theoretical state of charge can be determined through the correlation between the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell, and corrections can be made based on the actual situation of the theoretical state of charge to determine the target state of charge.

[0112] According to the method for determining the state of charge of the energy storage system provided in the embodiment of the present application, the electrical signal interval of each battery cell is obtained to determine the actual electrical signal interval of each battery cell, and the actual usage scenario of each battery cell is determined. Based on the actual usage scenario, different methods are used to determine the target state of charge of the target battery cell, reduce the error between the estimated state of charge and the actual value, improve the precision and accuracy of the determined target state of charge, improve the battery performance, and improve the user experience.

[0113] In some embodiments, step 120 may further include:

[0114] Based on the electrical signal of the target battery cell among the battery cells and the temperature of the target battery cell, searching the open circuit voltage-state of charge table to obtain the first state of charge of the target battery cell under the electrical signal and temperature;

[0115] The target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell.

[0116] In this embodiment, an open circuit voltage-state of charge (OCV-SOC) table is predetermined.

[0117] The first state of charge is the state of charge of the target battery cell obtained by looking up the open circuit voltage-state of charge table, which can be expressed as CellLookUpSoc n .

[0118] It is understandable that the electrical signal intervals of the battery cells may be the same or different.

[0119] During the actual execution process, the electrical signal interval of each battery cell in the battery pack is determined to judge the distribution of the electrical signal interval in the entire battery pack. Based on the distribution of the electrical signal interval of the entire battery pack, the first state of charge obtained by looking up the table and the theoretical state of charge of the target battery cell, it is determined whether the theoretical state of charge needs to be corrected and the method of correcting the theoretical state of charge. Based on the theoretical state of charge or the corrected theoretical state of charge, the target state of charge is determined.

[0120] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, the first state of charge of the target battery cell at the current collection moment is obtained by searching the open circuit voltage-state of charge table, and different judgment conditions are selected based on the distribution of the electrical signal interval of the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge to determine whether the theoretical state of charge needs to be corrected. If correction is required, the theoretical state of charge is corrected through different correction methods in different usage scenarios, and the correction method is flexibly selected to improve the accuracy of the correction result, thereby improving the accuracy of the determined target state of charge.

[0121] The following describes the methods for determining the target state of charge of the battery cell in different electrical signal intervals.

[0122] First, all electrical signal intervals are low-end non-platform areas

[0123] In some embodiments, determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell may further include:

[0124] When all the electric signal intervals are in the low-end non-platform area, the theoretical state of charge of the target battery cell is corrected to the first state of charge of the target battery cell;

[0125] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0126] In this embodiment, during the actual execution process, when all batteries in the battery pack where the target battery cell is located are in the low-end non-platform area, the theoretical state of charge of the target battery cell is corrected to the first state of charge to obtain a more accurate state of charge, and the corrected theoretical state of charge is determined as the target state of charge of the target battery cell.

[0127] According to the method for determining the state of charge of the energy storage system provided in the embodiment of the present application, by correcting the theoretical state of charge of the target battery cell to the first state of charge when it is determined that all the electrical signal intervals are in the low-end non-platform area, the correction method of the theoretical state of charge is effectively determined when the electrical signal interval of the battery pack as a whole is in the low-end non-platform area, thereby improving the accuracy of the target state of charge determined based on the theoretical state of charge.

[0128] Second, part of the electrical signal interval is the low-end non-platform area, and the rest is the platform area

[0129] In some embodiments, determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell may further include:

[0130] When at least part of the electrical signal interval is a low-end non-platform area, and the remaining part of the electrical signal interval except at least part is a platform area, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge and the low-end inflection point state of charge.

[0131] In this embodiment, the low-end inflection point state of charge is the state of charge corresponding to the inflection point of the low-end non-platform region of the open circuit voltage-state of charge curve corresponding to the open circuit voltage-state of charge table at the target temperature. The low-end inflection point state of charge can be expressed as .

[0132] like Figure 2 As shown, the low-end inflection point state of charge may be the state of charge SOC1 corresponding to the voltage V1.

[0133] The remaining part is other electrical signal intervals of the electrical signal intervals of the battery cells of the battery pack where the target battery cell is located, except for the low-end non-platform area.

[0134] In the actual implementation process, when it is determined that the electrical signal interval of each battery cell in the battery pack where the target battery cell is located is partly in the low-end non-platform area and the remaining part is in the platform area, different correction methods can be selected based on the correlation between the first state of charge of the target battery cell and the theoretical state of charge to correct the error of the theoretical state of charge and improve the accuracy of the determined target state of charge.

[0135] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by determining that the electrical signal interval of the battery pack includes two categories, namely, a low-end non-platform area and a platform area, a method for correcting the theoretical state of charge corresponding to the situation is selected, and based on the correlation between the first state of charge and the theoretical state of charge, a correction method is determined. The correction method is flexible, and different correction methods are selected based on different situations to improve the accuracy of the correction result and the correction efficiency.

[0136] In some embodiments, determining a target state of charge of a target battery cell based on the theoretical state of charge, the first state of charge, and the low-end inflection point state of charge may further include:

[0137] Obtaining difference information between a theoretical state of charge and a first state of charge;

[0138] Based on the theoretical state of charge, the first state of charge, the difference information and the low-end inflection point state of charge, a target state of charge of the target battery cell is determined.

[0139] In this embodiment, the difference information is information representing the degree of difference between the theoretical state of charge and the first state of charge.

[0140] The difference information may be determined by a difference between the theoretical state of charge and the first state of charge or a difference between the first state of charge and the theoretical state of charge.

[0141] The difference information may include: first difference information and second difference information.

[0142] The first difference information is difference information determined based on a difference between the first state of charge and the theoretical state of charge.

[0143] The second difference information is difference information determined based on a difference between the theoretical state of charge and the first state of charge.

[0144] In the actual implementation process, different methods can be selected to determine the difference information based on the correlation between the acquired theoretical state of charge and the first state of charge, so as to determine the correction method of the theoretical state of charge when part of the electrical signal interval is a low-end non-platform area and the remaining part is a platform area based on the correlation between the theoretical state of charge, the first state of charge, the difference information and the low-end inflection point state of charge, thereby determining the target state of charge of the target battery cell.

[0145] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, the actual situation between the theoretical state of charge and the first state of charge is determined by calculating the difference information between the theoretical state of charge and the first state of charge, and based on the difference information, a correction method for the theoretical state of charge is determined when part of the electrical signal interval is a low-end non-platform area and the remaining part is a platform area, so as to determine the target state of charge of the target battery cell, and different correction methods are selected based on different situations, and the correction method is flexible.

[0146] In some embodiments, determining a target state of charge of a target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge may further include:

[0147] When the first state of charge is greater than the theoretical state of charge, the difference information is greater than the first difference threshold, and the theoretical state of charge is less than the low-end inflection point state of charge, the theoretical state of charge corresponding to the target battery cell is corrected to the low-end inflection point state of charge;

[0148] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0149] In this embodiment, the first difference threshold is a preset value for determining whether the difference between the first state of charge and the theoretical state of charge exceeds a certain range. The first difference threshold may be expressed as SocBuff1.

[0150] The first difference threshold can be determined based on actual conditions and is not limited in this application.

[0151] In the actual execution process, when it is determined that the first state of charge is greater than the theoretical state of charge (i.e., CellLookUpSoc n >CellSoc n ), further comparing the correlation between the first difference information determined based on the first state of charge and the theoretical state of charge and the first difference threshold, and when the first difference information is greater than the first difference threshold (i.e., CellLookUpSoc n -CellSoc n >SocBuff1, and the theoretical state of charge is less than the low-end inflection point state of charge (i.e. CellSoc n ), the theoretical state of charge corresponding to the target battery cell is corrected to the low-end inflection point state of charge, so as to determine the target state of charge of the target battery cell based on the corrected theoretical state of charge.

[0152] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by further comparing the correlation between the first difference information and a given threshold value, and the correlation between the theoretical state of charge and the low-end inflection point state of charge when the first state of charge is greater than the theoretical state of charge, a plurality of judgment conditions are used to jointly determine whether to use the low-end inflection point state of charge to correct the theoretical state of charge, thereby improving the scientific nature of the judgment and the accuracy of the correction result, reducing the error of the theoretical state of charge, and thus improving the accuracy of the determined target state of charge.

[0153] In some embodiments, determining a target state of charge of a target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge may further include:

[0154] When the first state of charge is not greater than the theoretical state of charge, the difference information is greater than the second difference threshold, and the first state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge to the first state of charge;

[0155] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0156] In this embodiment, the second difference threshold is a preset value for determining whether the difference between the theoretical state of charge and the first state of charge exceeds a certain range. The second difference threshold may be expressed as SocBuff2.

[0157] The second difference threshold can be determined based on actual conditions and is not limited in this application.

[0158] In the actual implementation process, when it is determined that the theoretical state of charge is greater than the first state of charge (i.e., CellSoc n >CellLookUpSoc n ), further comparing the correlation between the second difference information determined based on the theoretical state of charge and the first state of charge and the second difference threshold, and when the second difference information is greater than the second difference threshold (i.e., CellSoc n -CellLookUpSoc n >SocBuff2, and the first state of charge is less than the low-end inflection point state of charge (i.e. CellLookUpSoc n ), the theoretical state of charge corresponding to the target battery cell is corrected to the first state of charge, so as to determine the target state of charge of the target battery cell based on the corrected theoretical state of charge.

[0159] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by further comparing the correlation between the second difference information and a given threshold, and the correlation between the first state of charge and the low-end inflection point state of charge when the theoretical state of charge is greater than the first state of charge, a plurality of judgment conditions are used to jointly determine whether to use the first state of charge to correct the theoretical state of charge, thereby improving the scientific nature of the judgment and the accuracy of the correction result, reducing the error of the theoretical state of charge, and thus improving the accuracy of the determined target state of charge.

[0160] Third, the electrical signal interval is the charging terminal

[0161] In some embodiments, determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell may further include:

[0162] When the battery pack where the target battery cell is located is not fully charged, the electrical signal interval of the target battery cell is the charging terminal, and the theoretical state of charge is less than the state of charge at the charging terminal inflection point, the theoretical state of charge is corrected to the state of charge at the charging terminal inflection point;

[0163] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0164] In this embodiment, the charging terminal inflection point state of charge is the state of charge corresponding to the inflection point of the charging terminal of the charging curve of the target battery cell at the target temperature.

[0165] The charging curve may be determined based on the change in voltage of the target battery cell over time and the state of charge during the charging process.

[0166] like Figure 3 As shown, the state of charge at the charging end inflection point may be the state of charge SOC2 corresponding to the voltage v2.

[0167] During the actual execution process, when the battery pack where the target battery cell is located is not fully charged and the voltage of the target battery cell is at the charging end, the correlation between the theoretical state of charge and the state of charge at the charging end inflection point is compared. When the theoretical state of charge is less than the state of charge at the charging end inflection point, the theoretical state of charge is corrected to the state of charge at the charging end inflection point, thereby determining the target state of charge of the target battery cell based on the corrected theoretical state of charge.

[0168] In the actual implementation process, when the electrical signal interval of the target battery cell is not at the charging end, the theoretical state of charge is not corrected.

[0169] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by determining whether the voltage range of the target battery cell is at the charging end, it is determined whether the theoretical state of charge is to be corrected. When it is determined that correction is required and the theoretical state of charge is less than the state of charge at the charging end inflection point, the theoretical state of charge is corrected to the state of charge at the charging end inflection point, which effectively corrects the theoretical state of charge of the target battery cell, reduces the error of the theoretical state of charge, and thus improves the accuracy of the target state of charge determined based on the theoretical state of charge.

[0170] In some embodiments, the method may further include:

[0171] Based on at least one of the battery health information and the number of charge and discharge cycles of each battery cell, the open circuit voltage-state of charge table is updated.

[0172] In this embodiment, the battery health information is used to characterize the health status of the battery cells.

[0173] Battery health information may be determined based on historical usage data of the battery cells.

[0174] Of course, in the actual implementation process, the battery health information can also be obtained based on any other feasible method.

[0175] The number of charge and discharge cycles is the number of times a battery cell completes a charge and discharge process.

[0176] It is understandable that the usage of the battery cell can be determined through one or more of the battery health information and the number of charge and discharge cycles to determine whether the battery cell is aged.

[0177] In the actual implementation process, when it is determined that the battery cells have aged to a certain extent based on the battery health information of each battery cell and one or more of the charge and discharge cycle numbers, the online update state of charge correction parameter strategy can be started to update the open circuit voltage-state of charge table.

[0178] According to the method for determining the state of charge of the energy storage system provided in the embodiment of the present application, whether the battery cell is aged is determined by the battery health information and the number of charge and discharge cycles of the battery cell, and an effective judgment is made based on the actual use of the battery cell to determine whether to update the open circuit voltage-state of charge table. In the case of aging of the battery cell, the open circuit voltage-state of charge table is updated in time to ensure the availability of the data in the open circuit voltage-state of charge table. In addition, when the battery is normal, no update is required to avoid invalid updates.

[0179] In some embodiments, based on at least one of the battery health information and the number of charge and discharge cycles of each battery cell, updating the open circuit voltage-state of charge table may also include:

[0180] When at least one of the battery health information is less than the target health threshold and the number of charge and discharge cycles is greater than the target cycle threshold, and the electrical signal interval of the target battery cell among the battery cells is a low-end non-platform area and the theoretical state of charge is corrected, a target temperature corresponding to the corrected theoretical state of charge of the target battery cell, an electrical signal corresponding to the corrected theoretical state of charge of the target battery cell, and a first state of charge corresponding to the corrected theoretical state of charge of the target battery cell are obtained;

[0181] An open circuit voltage-state of charge table is updated based on the target temperature, the electrical signal, and the first state of charge.

[0182] In this embodiment, the target health threshold is a preset value for determining whether the battery cell has aged to a certain extent.

[0183] The target health threshold can be determined based on actual conditions and is not limited in this application.

[0184] The target cycle threshold is a preset value for the number of charge and discharge cycles.

[0185] The target cycle threshold can be determined based on actual conditions and is not limited in this application.

[0186] In some embodiments, when the battery health information is less than a target health threshold, it may be determined that the open circuit voltage-state of charge table needs to be updated.

[0187] In some embodiments, when the number of charge and discharge cycles is greater than the target cycle threshold, it may be determined that the open circuit voltage-state of charge table needs to be updated.

[0188] In another embodiment, when the battery health information is less than the target health threshold and the number of charge and discharge cycles is greater than the target cycle threshold, it can be determined that the open circuit voltage-state of charge table needs to be updated.

[0189] The target temperature is the temperature of the target battery cell obtained during the process of correcting the theoretical state of charge.

[0190] The target temperature corresponding to the modified theoretical state of charge may be the temperature used in step 120 .

[0191] The electrical signal corresponding to the corrected theoretical state of charge of the target battery cell is the electrical signal of the target battery cell obtained during the process of correcting the theoretical state of charge.

[0192] The electrical signal corresponding to the target battery cell corrected theoretical state of charge may be the electrical signal used in step 120 .

[0193] The first state of charge corresponding to the corrected theoretical state of charge of the target battery cell is the state of charge of the target battery cell obtained by searching an open circuit voltage-state of charge table based on the temperature and electrical signal of the target battery cell.

[0194] In the actual implementation process, when it is determined that the open circuit voltage-state of charge table needs to be updated, the open circuit voltage-state of charge table may be updated based on the actual conditions of the battery cells.

[0195] In the actual implementation process, when the target battery cell among the battery cells is in the low-end non-platform region and the theoretical state of charge is corrected, the temperature, voltage and first state of charge of the target battery cell during correction may be recorded.

[0196] In some embodiments, after obtaining the target temperature corresponding to the target battery cell corrected theoretical state of charge, the electrical signal corresponding to the target battery cell corrected theoretical state of charge, and the first state of charge corresponding to the target battery cell corrected theoretical state of charge by recording the temperature, voltage, and first state of charge of the target battery cell during correction, the open circuit voltage-state of charge table can be updated based on the acquired information.

[0197] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, whether the battery cell has aged to a certain extent is determined through the actual use of the battery cell. When the battery cell has aged to a certain extent, the open circuit voltage-state of charge table is updated based on the temperature, electrical signal, first state of charge and other information recorded in the theoretical state of charge of the battery cell, and the open circuit voltage-state of charge table is updated based on the corrected data, so as to improve the accuracy of the updated open circuit voltage-state of charge table, reduce errors, and avoid the problem of inaccurate correction parameters caused by the aging of the battery cell.

[0198] In some embodiments, different methods may be selected to update the open circuit voltage-state of charge table based on the correlation between the first state of charge and the theoretical state of charge.

[0199] Different methods of updating the open circuit voltage-state of charge table are described below.

[0200] First, the correction method corresponding to the first state of charge being less than the theoretical state of charge

[0201] In some embodiments, updating the open circuit voltage-state of charge table based on the target temperature, the electrical signal, and the first state of charge includes:

[0202] When the first state of charge is less than the theoretical state of charge of the target battery cell and the battery pack where the target battery cell is located is fully charged within the target number of charge and discharge cycles, the second state of charge of the target battery cell at the target temperature is determined based on the maximum state of charge, the theoretical state of charge of the target battery cell at a collection moment before the battery pack where the target battery cell is located is fully charged, and the first state of charge; the maximum state of charge is the state of charge of the target battery cell when it is fully charged;

[0203] The open circuit voltage-state of charge table is updated based on the second state of charge of the target battery cell at the target temperature.

[0204] In this embodiment, the target charge-discharge cycle number is a preset value of the charge-discharge cycle number that avoids excessive ampere-hour integral accumulation error.

[0205] The specific value of the target number of charge and discharge cycles can be determined based on actual conditions and is not limited in this application.

[0206] The second state of charge is a state of charge used for updating the open circuit voltage-state of charge table when the first state of charge is less than the theoretical state of charge.

[0207] In some embodiments, when the first state of charge is less than the theoretical state of charge of the target battery cell, the open circuit voltage-state of charge table is updated based on the corresponding manner.

[0208] In the actual execution process, when the battery pack where the target battery cell is located is fully charged within the target number of charge and discharge cycles, the theoretical state of charge of the battery pack where the target battery cell is located at the previous acquisition time before full charge will jump to the maximum state of charge when it is fully charged. At this time, the state of charge error (i.e., deltaSOC) can be determined based on the maximum state of charge and the theoretical state of charge of the target battery cell at the acquisition time before the jump, so as to obtain the state of charge error based on the sum of the state of charge error and the first state of charge (i.e., CellLookUpSoc n +deltaSOC), update the open circuit voltage-state of charge table.

[0209] The state of charge error is determined based on the difference between the maximum state of charge and the theoretical state of charge of the target battery cell at a collection time before the battery pack where the target battery cell is located is fully charged.

[0210] For example, taking the open circuit voltage-state of charge table as an example of being low when it has not been updated for a long time, the theoretical state of charge in the low-end non-platform area is corrected to 20% (low), and the actual state of charge is 25%. Then during the charging process, the theoretical state of charge is fully charged from 75% to 95%. When fully charged, the theoretical state of charge will jump from 95% to 100%. At this time, it can be determined that the theoretical state of charge correction is 5% low (ie 100%-95%), that is, the SOC corresponding to the voltage and temperature when the low-end non-platform area is corrected is 25%, and the open circuit voltage-state of charge table is updated accordingly.

[0211] It is understandable that after the open circuit voltage-state of charge table at different temperatures is updated once, the open circuit voltage-state of charge table may be updated again according to the above method based on the target time interval.

[0212] The specific value of the target time interval can be determined based on actual conditions and is not limited in this application.

[0213] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, the state of charge error is determined by the difference between the maximum state of charge and the theoretical state of charge of the target battery cell at a collection moment before the battery pack where the target battery cell is located is fully charged. Therefore, based on the state of charge error and the first state of charge, the open circuit voltage-state of charge table is updated to avoid the problem of inaccurate correction parameters caused by aging of the battery cell and improve the accuracy of the determined target state of charge.

[0214] Second, the correction method corresponding to the first state of charge is not less than the theoretical state of charge

[0215] In some embodiments, updating the open circuit voltage-state of charge table based on the target temperature, the electrical signal, and the first state of charge includes:

[0216] When the first state of charge is not less than the theoretical state of charge of the target battery cell, and the difference between the state of charge of the battery pack where the target battery cell is located at the current collection time and the full charge is within the target range, the charging capacity accumulation information is obtained based on the state of charge threshold;

[0217] Determining a third state of charge of the target battery cell at the target temperature based on the first state of charge, the charging capacity accumulation information, and the maximum discharge capacity of the target battery cell at the target temperature;

[0218] The open circuit voltage-state of charge table is updated based on the third state of charge of the target battery cell at the target temperature.

[0219] In this embodiment, the target range is a preset value for determining that the battery pack is close to being fully charged.

[0220] The specific values ​​of the target range are determined based on actual conditions and are not limited in this application.

[0221] The state of charge threshold is the upper limit of the state of charge when the battery pack is fully charged.

[0222] The specific value of the state of charge threshold can be determined based on actual conditions. For example, the state of charge threshold can be 100% or 99.99%, etc., which is not limited in this application.

[0223] The charging capacity accumulation information is information obtained by accumulating the charging capacity when the difference between the charging state at the current collection time and the full charge is within the target range. The charging capacity accumulation information can be expressed as DeltaCap.

[0224] The charging capacity accumulation information stops accumulating when the target battery pack is fully charged, that is, when the state of charge threshold is reached.

[0225] The third state of charge is a state of charge used for updating the open circuit voltage-state of charge table when the first state of charge is not less than the theoretical state of charge.

[0226] In the actual execution process, within the target number of charge and discharge cycles, when the battery pack where the target battery cell is located is close to being fully charged, the charging state of the target battery pack at the current collection moment is at a certain waiting value until it is fully charged, at which point the charge state of the target battery pack becomes the upper limit of use (i.e., the charge state threshold).

[0227] When the difference between the charging state of the battery pack where the target battery cell is located at the current collection moment and the full charge is within the target range, it can be determined that the battery pack where the target battery cell is located is close to being fully charged. At this time, the charging capacity starts to be accumulated until the battery pack where the target battery cell is located is fully charged, and then the accumulation stops.

[0228] In some embodiments, after the charging capacity accumulation information is obtained, the third state of charge may be determined based on the difference between the first state of charge and the first ratio, so that the open circuit voltage-state of charge table is updated based on the third state of charge.

[0229] The first ratio is determined based on a ratio of the charging capacity accumulation information to a maximum discharge capacity of the target battery cell at a target temperature.

[0230] The maximum discharge capacity can be obtained by looking up the two-dimensional table of battery temperature difference-battery temperature capacity.

[0231] For example, the two-dimensional table of battery temperature difference-battery temperature capacity can be expressed as:

[0232] The X-axis is temperature (°C), for example [-20, -10, 0, 10, 20, 30, 40]

[0233] The Y-axis is capacity (Ah), for example [80, 100, 120, 160, 200, 220, 250].

[0234] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by using a correction method corresponding to a first state of charge that is not less than a theoretical state of charge, when the battery pack is nearly fully charged, charging capacity accumulation is performed, thereby determining a third state of charge of a target battery cell at a target temperature based on the obtained charging capacity accumulation information and data such as the first state of charge, thereby updating an open circuit voltage-state of charge table, avoiding the problem of inaccurate correction parameters caused by aging of the battery cell, and improving the precision and accuracy of the target state of charge determined based on the corrected theoretical state of charge.

[0235] In some embodiments, after updating the open circuit voltage-state of charge table based on the battery health information and the number of charge and discharge cycles of each battery cell, the method may further include:

[0236] Obtaining an open circuit voltage-state of charge curve corresponding to the updated open circuit voltage-state of charge table;

[0237] At least one of the low-end inflection point state of charge and the terminal-of-charge inflection point state of charge is updated based on the open-circuit voltage-state-of-charge curve.

[0238] In this embodiment, the open circuit voltage-state of charge curve is a curve determined based on data in the updated open circuit voltage-state of charge table.

[0239] During the actual execution process, the open circuit voltage-state of charge curve can be obtained based on the data in the updated open circuit voltage-state of charge table, so as to recalculate the point where the slope of the open circuit voltage-state of charge curve slows down based on the open circuit voltage-state of charge curve, that is, by judging whether the differential value (dV / dSoc) of the open circuit voltage-state of charge curve is less than the target slope threshold, so as to update the low-end inflection point state of charge.

[0240] The target slope threshold can be determined based on actual conditions and is not limited in this application.

[0241] It is understandable that with the long-term operation of the battery cell, the charging end of the battery cell charging curve may shift, and it is necessary to re-judge the boundary point of the charging end, that is, to update the charging end inflection point charge state.

[0242] In some embodiments, when the charging current of the target battery cell is less than the target current threshold and the temperature of the target battery cell is less than the target temperature threshold, the charging terminal inflection point state of charge is updated based on the differential value of the charging curve and the target slope threshold.

[0243] During the actual execution process, when the charging current of the target battery cell is less than the target current threshold and the temperature of the target battery cell is less than the target temperature threshold, the correlation between the differential value of the charging curve and the target slope threshold is further judged. When the differential value of the charging curve is greater than the target slope threshold, it is approximately considered that the voltage difference changes greatly within a period of time or a cycle. At this time, the charge state at the inflection point of the charging terminal can be updated to the charge state and voltage value corresponding to the point where the differential value of the charging curve is greater than the target slope threshold, so as to update the charge state at the inflection point of the charging terminal.

[0244] According to the method for determining the state of charge of an energy storage system provided in an embodiment of the present application, by obtaining an open circuit voltage-state of charge curve corresponding to an updated open circuit voltage-state of charge table, the low-end inflection point state of charge and the charging terminal inflection point state of charge are updated based on the differential value of the open circuit voltage-state of charge curve, so as to cope with the situation where the low-end inflection point state of charge and the charging terminal inflection point state of charge are offset due to battery aging, improve the accuracy of the correction parameters, and thus improve the accuracy of the target state of charge determined subsequently.

[0245] The state of charge determination method of the energy storage system provided in the embodiment of the present application can be executed by a state of charge determination device of the energy storage system. In the embodiment of the present application, the state of charge determination device of the energy storage system executing the state of charge determination method of the energy storage system is taken as an example to illustrate the state of charge determination device of the energy storage system provided in the embodiment of the present application.

[0246] An embodiment of the present application also provides a device for determining a state of charge of an energy storage system.

[0247] The energy storage system includes at least one battery pack.

[0248] Each battery pack includes at least one battery cell.

[0249] like Figure 4 As shown, the charge state determination device of the energy storage system includes: a first processing module 410 and a second processing module 420.

[0250] The first processing module 410 is used to obtain the electrical signal interval of each battery cell; the electrical signal interval includes: a low-end non-platform area, a platform area, and a charging terminal;

[0251] The second processing module 420 is used to determine the target state of charge of each battery cell based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell.

[0252] According to the device for determining the state of charge of the energy storage system provided in the embodiment of the present application, by acquiring the electrical signal interval of each battery cell, the electrical signal interval in which each battery cell is actually located is determined, the actual usage scenario of each battery cell is determined, and based on the actual usage scenario, different methods are adopted to determine the target state of charge of the target battery cell, thereby reducing the error between the estimated state of charge and the actual value, improving the precision and accuracy of the determined target state of charge, improving the battery performance, and improving the user experience.

[0253] In some embodiments, the second processing module 420 may also be used to:

[0254] Based on the electrical signal of the target battery cell among the battery cells and the temperature of the target battery cell, searching the open circuit voltage-state of charge table to obtain the first state of charge of the target battery cell under the electrical signal and temperature; the open circuit voltage-state of charge table is predetermined;

[0255] The target state of charge of the target battery cell is determined based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell.

[0256] In some embodiments, the second processing module 420 may also be used to:

[0257] Determining a target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell includes:

[0258] When all the electric signal intervals are in the low-end non-platform area, the theoretical state of charge of the target battery cell is corrected to the first state of charge of the target battery cell;

[0259] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0260] In some embodiments, the second processing module 420 may also be used to:

[0261] When at least part of the electrical signal interval is a low-end non-platform area, and the remaining part of the electrical signal interval except at least part is a platform area, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge and the low-end inflection point state of charge; the low-end inflection point state of charge is the state of charge corresponding to the inflection point of the low-end non-platform area of ​​the open circuit voltage-state of charge curve corresponding to the open circuit voltage-state of charge table at the target temperature.

[0262] In some embodiments, the second processing module 420 may also be used to:

[0263] Obtaining difference information between a theoretical state of charge and a first state of charge;

[0264] Based on the theoretical state of charge, the first state of charge, the difference information and the low-end inflection point state of charge, a target state of charge of the target battery cell is determined.

[0265] In some embodiments, the second processing module 420 may also be used to:

[0266] When the first state of charge is greater than the theoretical state of charge, the difference information is greater than the first difference threshold, and the theoretical state of charge is less than the low-end inflection point state of charge, the theoretical state of charge corresponding to the target battery cell is corrected to the low-end inflection point state of charge;

[0267] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0268] In some embodiments, the second processing module 420 may also be used to:

[0269] When the first state of charge is not greater than the theoretical state of charge, the difference information is greater than the second difference threshold, and the first state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge to the first state of charge;

[0270] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0271] In some embodiments, the second processing module 420 may also be used to:

[0272] When the battery pack where the target battery cell is located is not fully charged, the electrical signal interval of the target battery cell is the charging terminal, and the theoretical state of charge is less than the state of charge at the charging terminal inflection point, the theoretical state of charge is corrected to the state of charge at the charging terminal inflection point; the state of charge at the charging terminal inflection point is the state of charge corresponding to the inflection point of the charging terminal of the charging curve of the target battery cell at the target temperature;

[0273] Based on the corrected theoretical state of charge, a target state of charge of the target battery cell is determined.

[0274] In some embodiments, the first processing module 410 may also be used to:

[0275] When the electrical signal collected from the target battery cell among the battery cells after being left at rest for the target time is less than the first electrical signal threshold, determining the electrical signal interval of the target battery cell as a low-end non-platform area;

[0276] When the electrical signal of the target battery cell among the battery cells collected after being left at rest for the target time is not less than the first electrical signal threshold, determining the electrical signal interval of the target battery cell as a platform area;

[0277] When the charging current of the target battery cell among the battery cells is less than the first current threshold and the electrical signal collected by the target battery cell during charging is greater than the second electrical signal threshold, the electrical signal interval of the target battery cell is determined to be the charging end.

[0278] In some embodiments, the apparatus may further include a third processing module, configured to:

[0279] Based on at least one of the battery health information and the number of charge and discharge cycles of each battery cell, the open circuit voltage-state of charge table is updated.

[0280] In some embodiments, the apparatus may further include a fourth processing module, configured to:

[0281] When at least one of the battery health information is less than the target health threshold and the number of charge and discharge cycles is greater than the target cycle threshold, and the electrical signal interval of the target battery cell among the battery cells is a low-end non-platform area and the theoretical state of charge is corrected, a target temperature corresponding to the corrected theoretical state of charge of the target battery cell, an electrical signal corresponding to the corrected theoretical state of charge of the target battery cell, and a first state of charge corresponding to the corrected theoretical state of charge of the target battery cell are obtained;

[0282] An open circuit voltage-state of charge table is updated based on the target temperature, the electrical signal, and the first state of charge.

[0283] In some embodiments, the apparatus may further include a fifth processing module, configured to:

[0284] When the first state of charge is less than the theoretical state of charge of the target battery cell and the battery pack where the target battery cell is located is fully charged within the target number of charge and discharge cycles, the second state of charge of the target battery cell at the target temperature is determined based on the maximum state of charge, the theoretical state of charge of the target battery cell at a collection moment before the battery pack where the target battery cell is located is fully charged, and the first state of charge; the maximum state of charge is the state of charge of the target battery cell when it is fully charged;

[0285] The open circuit voltage-state of charge table is updated based on the second state of charge of the target battery cell at the target temperature.

[0286] In some embodiments, the apparatus may further include a sixth processing module, configured to:

[0287] When the first state of charge is not less than the theoretical state of charge of the target battery cell, and the difference between the state of charge of the battery pack where the target battery cell is located at the current collection time and the full charge is within the target range, the charging capacity accumulation information is obtained based on the state of charge threshold;

[0288] Determining a third state of charge of the target battery cell at the target temperature based on the first state of charge, the charging capacity accumulation information, and the maximum discharge capacity of the target battery cell at the target temperature;

[0289] The open circuit voltage-state of charge table is updated based on the third state of charge of the target battery cell at the target temperature.

[0290] In some embodiments, the apparatus may further include a seventh processing module, configured to:

[0291] Obtaining an open circuit voltage-state of charge curve corresponding to the updated open circuit voltage-state of charge table;

[0292] At least one of the low-end inflection point state of charge and the terminal-of-charge inflection point state of charge is updated based on the open-circuit voltage-state-of-charge curve.

[0293] The charge state determination device of the energy storage system in the embodiment of the present application may be an energy storage system, or an electronic device connected to the energy storage system for communication, or a component in the electronic device, such as an integrated circuit or a chip. The electronic device may be a terminal, or may be other devices other than a terminal. Exemplarily, the electronic device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet device (Mobile Internet Device, MID), an augmented reality (augmented reality, AR) / virtual reality (virtual reality, VR) device, a robot, a wearable device, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a netbook or a personal digital assistant (personal digital assistant, PDA), etc. It may also be a server, a network attached storage (Network Attached Storage, NAS), a personal computer (personal computer, PC), a television (television, TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiment of the present application.

[0294] The charge state determination device of the energy storage system in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an IOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0295] The charge state determination device of the energy storage system provided in the embodiment of the present application can achieve Figures 1 to 3 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0296] In some embodiments, Figure 5 As shown, an embodiment of the present application further provides an electronic device 500, including a processor 501, a memory 502, and a computer program stored in the memory 502 and executable on the processor 501. When the program is executed by the processor 501, each process of the embodiment of the method for determining the state of charge of the energy storage system described above is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0297] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0298] The embodiment of the present application also provides an energy storage system.

[0299] In some embodiments, the energy storage system includes: at least one battery pack.

[0300] In this embodiment, each battery pack includes at least one battery cell.

[0301] According to the energy storage system provided in the embodiment of the present application, by acquiring the electrical signal interval of each battery cell, determining the actual electrical signal interval of each battery cell, determining the actual usage scenario of each battery cell, and based on the actual usage scenario, adopting different methods to determine the target state of charge of the target battery cell, reducing the error between the estimated state of charge and the actual value, improving the precision and accuracy of the determined target state of charge, improving the battery performance, and improving the user experience.

[0302] The embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each process of the embodiment of the method for determining the state of charge of the energy storage system described above is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0303] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0304] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the method for determining the state of charge of the energy storage system.

[0305] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0306] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned energy storage system charge state determination method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0307] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0308] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0309] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the relevant technology, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, disk, CD), and includes a number of instructions for a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0310] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0311] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0312] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for determining the state of charge of an energy storage system, characterized in that: The energy storage system includes at least one battery pack, each of which includes at least one battery cell, and the method includes: Acquire the electrical signal interval of each battery cell; the electrical signal interval includes: a low-end non-platform area, a platform area, and a charging terminal; Determining a target state of charge of each battery cell based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell, and the theoretical state of charge of each battery cell; The determining the target state of charge of each battery cell based on the electrical signal interval corresponding to each battery cell, the electrical signal of each battery cell, the temperature of each battery cell and the theoretical state of charge of each battery cell includes: Based on the electrical signal of the target battery cell in each of the battery cells and the temperature of the target battery cell, searching an open circuit voltage-state of charge table to obtain a first state of charge of the target battery cell under the electrical signal and the temperature; the open circuit voltage-state of charge table is predetermined; Determine the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell; The determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell includes: In the case where at least a portion of the electrical signal interval is the low-end non-platform area, and the remaining portion of the electrical signal interval except the at least a portion is the platform area, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge, and the low-end inflection point state of charge; the low-end inflection point state of charge is the state of charge corresponding to the inflection point of the low-end non-platform area of ​​the open circuit voltage-state of charge curve corresponding to the open circuit voltage-state of charge table at the target temperature; The determining the target state of charge of the target battery cell based on the theoretical state of charge, the first state of charge, and the low-end inflection point state of charge includes: Acquiring difference information between the theoretical state of charge and the first state of charge; Determining the target state of charge of the target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge; The determining the target state of charge of the target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge includes: When the first state of charge is greater than the theoretical state of charge, the difference information is greater than a first difference threshold, and the theoretical state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge corresponding to the target battery cell to the low-end inflection point state of charge; Determining the target state of charge of the target battery cell based on the corrected theoretical state of charge; The determining the target state of charge of the target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge includes: In the case where the first state of charge is not greater than the theoretical state of charge, the difference information is greater than a second difference threshold, and the first state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge to the first state of charge; Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

2. The method for determining the state of charge of an energy storage system according to claim 1, characterized in that: The determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell includes: When all of the electrical signal intervals are in the low-end non-platform region, correcting the theoretical state of charge of the target battery cell to the first state of charge of the target battery cell; Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

3. The method for determining the state of charge of an energy storage system according to claim 1, characterized in that: The determining the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell includes: In the case where the battery pack where the target battery cell is located is not fully charged, the electrical signal interval of the target battery cell is the charging terminal, and the theoretical state of charge is less than the state of charge at the charging terminal inflection point; the state of charge at the charging terminal inflection point is the state of charge corresponding to the inflection point of the charging terminal of the charging curve of the target battery cell at the target temperature; Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

4. The method for determining the state of charge of an energy storage system according to any one of claims 1 to 3, characterized in that: The electrical signal interval is determined based on the following steps: When the electrical signal collected from the target battery cell among the battery cells after being left at rest for a target time is less than a first electrical signal threshold, determining the electrical signal interval of the target battery cell as the low-end non-platform area; When the electrical signal of a target battery cell among the battery cells collected after being left at rest for a target time is not less than a first electrical signal threshold, determining the electrical signal interval of the target battery cell as the platform area; When the charging current of a target battery cell among the battery cells is less than a first current threshold and the electrical signal collected by the target battery cell during charging is greater than a second electrical signal threshold, the electrical signal interval of the target battery cell is determined as the charging end.

5. The method for determining the state of charge of an energy storage system according to any one of claims 1 to 3, characterized in that: Also includes: Based on at least one of the battery health information and the number of charge and discharge cycles of each of the battery cells, an open circuit voltage-state of charge table is updated.

6. The method for determining the state of charge of the energy storage system according to claim 5, characterized in that: The updating of the open circuit voltage-state of charge table based on at least one of the battery health information and the number of charge and discharge cycles of each battery cell comprises: When at least one of the battery health information is less than a target health threshold and the number of charge and discharge cycles is greater than a target cycle threshold, and the electrical signal interval of a target battery cell among the battery cells is the low-end non-platform area and the theoretical state of charge is corrected, obtaining a target temperature corresponding to the target battery cell correcting the theoretical state of charge, an electrical signal corresponding to the target battery cell correcting the theoretical state of charge, and a first state of charge corresponding to the target battery cell correcting the theoretical state of charge; updating the open circuit voltage-state of charge table based on the target temperature, the electrical signal, and the first state of charge; The updating of the open circuit voltage-state of charge table based on the target temperature, the electrical signal, and the first state of charge includes: When the first state of charge is less than the theoretical state of charge of the target battery cell and the battery pack where the target battery cell is located is fully charged within the target number of charge and discharge cycles, the second state of charge of the target battery cell at the target temperature is determined based on the maximum state of charge, the theoretical state of charge of the target battery cell at a collection moment before the battery pack where the target battery cell is located is fully charged, and the first state of charge; the maximum state of charge is the state of charge of the target battery cell when it is fully charged; updating the open circuit voltage-state of charge table based on the second state of charge of the target battery cell at the target temperature; The updating of the open circuit voltage-state of charge table based on the target temperature, the electrical signal, and the first state of charge includes: When the first state of charge is not less than the theoretical state of charge of the target battery cell, and the difference between the state of charge of the battery pack where the target battery cell is located at the current collection time and the full charge is within a target range, the charging capacity accumulation information is obtained based on the state of charge threshold; determining a third state of charge of the target battery cell at the target temperature based on the first state of charge, the charging capacity accumulation information, and a maximum discharge capacity of the target battery cell at the target temperature; The open circuit voltage-state of charge table is updated based on a third state of charge of the target battery cell at the target temperature.

7. The method for determining the state of charge of an energy storage system according to claim 5, characterized in that: After updating the open circuit voltage-state of charge table based on at least one of the battery health information and the number of charge and discharge cycles of each of the battery cells, the method further includes: Obtaining an open circuit voltage-state of charge curve corresponding to the updated open circuit voltage-state of charge table; At least one of the low-end inflection point state of charge and the charging terminal inflection point state of charge is updated based on the open circuit voltage-state of charge curve.

8. A device for determining a state of charge of an energy storage system, characterized in that: The energy storage system includes at least one battery pack, each of which includes at least one battery cell, and the device includes: A first processing module is used to obtain the electrical signal interval of each battery cell; the electrical signal interval includes: a low-end non-platform area, a platform area and a charging terminal; a second processing module, configured to determine a target state of charge of each battery cell based on an electrical signal interval corresponding to each battery cell, an electrical signal of each battery cell, a temperature of each battery cell, and a theoretical state of charge of each battery cell; The second processing module is also used for: Based on the electrical signal of the target battery cell in each of the battery cells and the temperature of the target battery cell, searching an open circuit voltage-state of charge table to obtain a first state of charge of the target battery cell under the electrical signal and the temperature; the open circuit voltage-state of charge table is predetermined; Determine the target state of charge of the target battery cell based on the electrical signal interval of each battery cell in the battery pack where the target battery cell is located, the first state of charge, and the theoretical state of charge of the target battery cell; The second processing module is also used for: In the case where at least a portion of the electrical signal interval is the low-end non-platform area, and the remaining portion of the electrical signal interval except the at least a portion is the platform area, the target state of charge of the target battery cell is determined based on the theoretical state of charge, the first state of charge, and the low-end inflection point state of charge; the low-end inflection point state of charge is the state of charge corresponding to the inflection point of the low-end non-platform area of ​​the open circuit voltage-state of charge curve corresponding to the open circuit voltage-state of charge table at the target temperature; The second processing module is also used for: Acquiring difference information between the theoretical state of charge and the first state of charge; Determining the target state of charge of the target battery cell based on the theoretical state of charge, the first state of charge, the difference information, and the low-end inflection point state of charge; The second processing module is also used for: When the first state of charge is greater than the theoretical state of charge, the difference information is greater than a first difference threshold, and the theoretical state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge corresponding to the target battery cell to the low-end inflection point state of charge; Determining the target state of charge of the target battery cell based on the corrected theoretical state of charge; The second processing module is also used for: In the case where the first state of charge is not greater than the theoretical state of charge, the difference information is greater than a second difference threshold, and the first state of charge is less than the low-end inflection point state of charge, correcting the theoretical state of charge to the first state of charge; Based on the corrected theoretical state of charge, the target state of charge of the target battery cell is determined.

9. An energy storage system, characterized in that: include: at least one battery pack, each of the battery packs comprising at least one battery cell; The energy storage system determines the state of charge based on the method for determining the state of charge of the energy storage system according to any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the method for determining the state of charge of the energy storage system as described in any one of claims 1 to 7 is implemented.

11. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for determining the state of charge of the energy storage system as described in any one of claims 1 to 7 is implemented.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for determining the state of charge of the energy storage system according to any one of claims 1 to 7 is implemented.

Images