Charge state determination method, electronic equipment and storage medium

Abstract

The invention provides a state-of-charge determination method, electronic equipment and a storage medium, and the method comprises the steps: obtaining a port voltage value of a target battery at a current moment in response to the starting of power-on work of the target battery, and judging whether the port voltage value is greater than a preset voltage threshold value of the target battery; in response to the fact that the port voltage value is larger than a preset voltage threshold value, the current value and the power-on duration time of the target battery at the current moment are obtained respectively, and whether the current value and the power-on duration time both meet preset conditions or not is judged; and determining a first charge state value of the target battery at the current moment by using a predetermined relationship calculation formula of open-circuit voltage and charge state based on the port voltage value in response to the condition that both the current value and the power-on duration meet preset conditions. By means of the method, the problems that the complexity of determining the state of charge of the battery is too high and the limitation is large are solved, and then the accuracy of determining the state of charge of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery power technology, and in particular to a method for determining a state of charge, an electronic device, and a storage medium. Background Art

[0002] As a key equipment in the photovoltaic new energy industry, energy storage photovoltaic inverters are of great significance to improving the efficiency of new energy power generation, reducing operating costs, and enhancing system stability. Among them, lead-acid batteries, as key components of energy storage photovoltaic inverters, have the advantages of large capacity, low price, and maintenance-free. In practical applications, in order to ensure the excellent performance of the battery and extend its service life, it is usually necessary to accurately obtain the battery's state of charge (SOC) in order to accurately manage the battery's charge and discharge.

[0003] At present, the ampere-hour method is generally used to obtain the state of charge of the battery. The change in the state of charge is estimated by measuring the integral of the battery's charge and discharge current over time. However, the ampere-hour method cannot estimate the initial state of charge of the battery, and due to the existence of sampling errors, with the long-term accumulation of errors, the deviation of the state of charge value will become larger and larger, reducing the accuracy of determining the battery's state of charge. In addition, the ampere-hour method requires a complete charge and discharge process to estimate the battery's state of charge, and the charge and discharge current in the estimation process needs to be in a certain specific range to obtain relatively accurate data, which has great limitations, thereby increasing the complexity of determining the state of charge. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a method for determining the state of charge, an electronic device and a storage medium, to confirm that the battery is not in a serious power-deficient state when the target battery starts to power on, and to further determine whether the current value and power-on duration of the target battery obtained at the current moment both meet preset conditions. When it is determined that both preset conditions are met, the state of charge value of the target battery at the current moment is determined based on the port voltage value of the target battery and by utilizing the relationship between the predetermined open circuit voltage and the state of charge. In this way, the problems of excessive complexity and limitations in determining the state of charge of the battery are avoided, thereby improving the accuracy of determining the state of charge of the battery.

[0005] Based on the above purpose, in a first aspect, the present application provides a method for determining a state of charge, comprising:

[0006] In response to the target battery starting to power on, obtaining a port voltage value of the target battery at a current moment, and determining whether the port voltage value is greater than a preset voltage threshold of the target battery;

[0007] In response to the port voltage value being greater than the preset voltage threshold, respectively obtaining the current value and the power-on duration of the target battery at the current moment, and determining whether both the current value and the power-on duration meet preset conditions;

[0008] In response to the current value and the power-on duration both satisfying preset conditions, based on the port voltage value, a first state of charge value of the target battery at the current moment is determined using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge.

[0009] In a second aspect of the present application, a device for determining a state of charge is provided, comprising:

[0010] A first judgment module, configured to obtain a port voltage value of the target battery at a current moment in response to the target battery starting to power on, and to judge whether the port voltage value is greater than a preset voltage threshold of the target battery;

[0011] a second judgment module, configured to respectively obtain a current value and a power-on duration of the target battery at a current moment in response to the port voltage value being greater than the preset voltage threshold, and to judge whether both the current value and the power-on duration meet preset conditions;

[0012] The numerical determination module determines, in response to the current value and the power-on duration satisfying preset conditions, a first state of charge value of the target battery at the current moment based on the port voltage value and using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge.

[0013] In a third aspect of the present application, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.

[0014] According to a fourth aspect of the present application, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores computer instructions, wherein the computer instructions are used to enable a computer to execute the method described in the first aspect.

[0015] In a fifth aspect of the present application, a computer program product is provided, comprising computer program instructions, which, when executed on a computer, cause the computer to execute the method described in the first aspect.

[0016] From the above, it can be seen that the method for determining the state of charge, the electronic device, and the storage medium provided in the embodiments of the present application confirm that the battery is not in a serious power-deficient state when the target battery starts to power on, and further determine whether the current value and power-on duration of the target battery obtained at the current moment both meet the preset conditions. When it is determined that both the preset conditions are met, the state of charge value of the target battery at the current moment is determined based on the port voltage value of the target battery by utilizing the relationship between the predetermined open circuit voltage and the state of charge.

[0017] Compared with the methods in the prior art including the internal resistance method and the discharge test method, the problem of high complexity and large limitations in determining the state of charge of the battery is avoided, thereby improving the accuracy of determining the state of charge of the battery.

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 One of the flowcharts of an exemplary method for determining a state of charge according to an embodiment of the present application is shown;

[0021] Figure 2 A second flowchart of an exemplary method for determining a state of charge according to an embodiment of the present application is shown;

[0022] Figure 3 A flow chart of an exemplary repetitive pulse discharge experiment according to an embodiment of the present application is shown;

[0023] Figure 4 One of the schematic diagrams showing the relationship between the port voltage and the power-on duration of an exemplary target battery according to an embodiment of the present application is shown;

[0024] Figure 5 A second schematic diagram showing the relationship between the port voltage and the power-on duration of an exemplary target battery according to an embodiment of the present application;

[0025] Figure 6 A schematic structural diagram of an exemplary charge state determination device according to an embodiment of the present application is shown;

[0026] Figure 7A schematic structural diagram of an exemplary electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] Through research, it is found that in the related art, determining the state of charge value of a battery generally includes the following methods.

[0030] The first method is the internal resistance method. This method requires sweeping the input port of the battery to obtain the equivalent internal resistance, which increases the complexity of determining the state of charge and is inconvenient to use.

[0031] The second method is the discharge test method. This method uses a constant current to continuously discharge the battery, and the product of the discharge current and the duration is taken as the remaining power; however, this method needs to be used in a laboratory and the working battery needs to be interrupted, so it has great limitations.

[0032] The third method is the neural network method. Since the battery is a highly nonlinear system, it is difficult to establish an accurate mathematical model for the battery charging and discharging process. The neural network has the basic characteristics of nonlinearity and can simulate the dynamic characteristics of the battery. The neural network has strong adaptability in estimating the battery state of charge; however, this method requires a large amount of reference data for training and has a large amount of calculation.

[0033] The fourth method is the Kalman filter method. This method has high accuracy and strong anti-interference ability, but the error in determining the state of charge at the initial moment when the battery is powered on is large.

[0034] The fifth method is the ampere-hour method. This method is also called the coulomb counting method. It estimates the change of the state of charge by measuring the integral of the battery's charge and discharge current over time. However, the ampere-hour method cannot estimate the initial state of charge of the battery, and due to the existence of sampling errors, as the errors accumulate over a long period of time, the deviation of the state of charge value will become larger and larger, resulting in inaccurate state of charge estimation. In addition, the ampere-hour method requires a complete charge and discharge process to estimate the battery's state of charge, and the charge and discharge current in the estimation process needs to be in a certain specific range to obtain relatively accurate data, which has great limitations, thereby increasing the complexity of determining the state of charge.

[0035] The sixth method is the open circuit voltage method. This method estimates the state of charge of the battery by measuring the open circuit voltage of the battery. Since there is a good linear relationship between the open circuit voltage of the battery and the state of charge, the state of charge of the battery can be estimated by measuring the open circuit voltage of the battery; however, the battery needs to be left at rest for a long time to obtain a stable open circuit voltage value.

[0036] In summary, in the related art, the limitations and complexity of determining the state of charge of a battery are high, while the accuracy and flexibility are low, making it difficult to provide users with a good user experience in the engineering applications and life applications of the battery.

[0037] Based on this, an embodiment of the present application provides a method for determining the state of charge, which confirms that the battery is not in a serious power-deficient state when the target battery starts to power on, and further determines whether the current value and power-on duration of the target battery obtained at the current moment both meet preset conditions. When it is determined that both preset conditions are met, the state of charge value of the target battery at the current moment is determined based on the port voltage value of the target battery and the relationship between the open circuit voltage and the state of charge determined in advance. In this way, the problems of excessive complexity and limitations in determining the state of charge of the battery are avoided, thereby improving the accuracy of determining the state of charge of the battery.

[0038] Figure 1 One of the flowcharts of an exemplary method for determining a state of charge according to an embodiment of the present application is shown.

[0039] The state of charge determination method of the present application can determine the state of charge of the energy storage component in the photovoltaic energy storage device, thereby avoiding the result deviation caused by error accumulation when determining the state of charge of the energy storage component in the related art.

[0040] In an embodiment of the present application, a photovoltaic energy storage device (for example, a photovoltaic energy storage inverter) may include a current conversion unit (for example, an inverter) for converting direct current into alternating current, and an energy storage unit (for example, a lead-acid battery) for storing electrical energy and performing charge and discharge control. A battery management system (BMS) is integrated into the energy storage unit, and the method for determining the state of charge in the present application can be implemented through the battery management system.

[0041] like Figure 1 As shown in , the method for determining the state of charge provided by the embodiment of the present application may include the following steps. In step S100, in response to the target battery starting to power on, the port voltage value of the target battery at the current moment is obtained, and it is determined whether the port voltage value is greater than a preset voltage threshold of the target battery.

[0042] It should be noted that the target battery can be a lead-acid battery, which can release electrical energy when working and restore its stored energy by charging when conditions permit; wherein, the lead-acid battery has the advantages of large capacity, low price, maintenance-free, etc., and there is a good and stable linear relationship between the open circuit voltage value and the state of charge value of the lead-acid battery.

[0043] In an embodiment of the present application, when the battery management system detects that the target battery starts to power on, that is, when the target battery starts to operate in the photovoltaic energy storage device, in response to the power-on (operation) signal, the port voltage value of the target battery at the current moment collected by the sensor in the battery management system is obtained, and the port voltage value is further compared with the preset voltage threshold of the target battery to determine whether the port voltage value is greater than the preset voltage threshold.

[0044] The port voltage value refers to the actual voltage measured at both ends of the battery when the battery is connected to a load or a power source. The port voltage value reflects the working state of the battery under specific load conditions.

[0045] The preset voltage threshold of the target battery may include a preset low voltage disconnect voltage value (Low Voltage Disconnect, LVD) of the target battery. The low voltage disconnect voltage refers to a voltage threshold set in a battery management system (Battery Management System, BMS) to protect the battery from damage caused by excessive discharge, so as to avoid permanent damage or reduced battery life caused by excessive discharge of the battery.

[0046] Figure 2 A second flowchart of an exemplary method for determining a state of charge according to an embodiment of the present application is shown.

[0047] like Figure 2 As shown in , the determination method further includes the following steps.

[0048] In step S400, in response to the port voltage value being less than or equal to the preset voltage threshold, based on the mapping relationship between the open circuit voltage and the state of charge of the target battery, a preset value is determined as the second state of charge value of the target battery at the current moment.

[0049] In an embodiment of the present application, when the port voltage value of the target battery is less than or equal to the preset low-voltage disconnection voltage of the target battery, it indicates that the target battery is in a serious power-loss state at the current moment. In order to protect the target battery from permanent damage or the risk of reducing the battery life, the preset value is determined as the second state of charge value of the target battery at the current moment.

[0050] Here, the second state of charge value refers to the state of charge value corresponding to when the terminal voltage value of the target battery at the current moment is less than or equal to the preset low voltage disconnection voltage of the target battery.

[0051] In an embodiment of the present application, the preset value may be set to 0, so that when the port voltage value of the target battery is less than or equal to the preset low voltage disconnection voltage of the target battery, the second state of charge value of the target battery at the current moment is determined to be 0.

[0052] Here, when the port voltage value of the target battery drops to the low-voltage disconnection voltage, based on the mapping relationship between the open-circuit voltage of the target battery and the state of charge, that is, the SOC-OCV curve, it can be determined that the state of charge value at the current moment is close to 0. Therefore, the preset value is set to 0, that is, the second state of charge value of the target battery at the current moment is determined to be 0.

[0053] like Figure 1 As shown in, in step S200, in response to the port voltage value being greater than the preset voltage threshold, the current value and the power-on duration of the target battery at the current moment are respectively obtained, and it is determined whether the current value and the power-on duration both meet the preset conditions.

[0054] In an embodiment of the present application, in response to the port voltage value of the target battery being greater than the preset voltage threshold (low-voltage disconnect voltage value), the current value of the target battery at the current moment collected by the current acquisition sensor in the battery management system is obtained, and the power-on duration of the target battery recorded in the timer is obtained. Among them, the timer can be set in the energy storage unit or in the battery management system. It can be used to record the length of time since the target battery was powered on. In the present application, by combining the current value and the power-on duration at the current moment, the battery management system can more accurately estimate the state of charge of the target battery.

[0055] In some embodiments, the determination of whether the current value and the power-on duration both satisfy preset conditions further includes: determining whether the current value is less than a preset current threshold; if the current value is less than the preset current threshold, then based on the power-on duration, determining the duration of the current moment relative to the moment corresponding to the first time the current value is less than the preset current threshold, and determining whether the duration is greater than a predetermined recovery time threshold of the target battery; if the duration is greater than the recovery time threshold, determining that the current value and the power-on duration both satisfy the preset conditions.

[0056] Further, if the current value is greater than or equal to a preset current threshold or the duration is less than or equal to the recovery time threshold, it is determined that the current value or the power-on duration does not meet a preset condition.

[0057] In an embodiment of the present application, the preset condition includes that the current value of the target battery is less than a preset current threshold and the duration from the current moment to the moment corresponding to the first time the current value is less than the preset current threshold is greater than a predetermined recovery time threshold.

[0058] Here, the preset current threshold can be set to 0.02 times the rated capacity of the battery (0.02C) to ensure that the target battery is in a light load state. In this way, the impact on the open circuit voltage of the target battery measured after the voltage stabilizes is small. The preset current threshold is not limited to being set to 0.02 times the rated capacity of the battery.

[0059] It should be noted that setting the preset current threshold to 0.02 times (0.02C) of the rated capacity of the battery is the optimal solution creatively discovered and obtained by the inventor of the present application after a series of experiments. Although the preset current threshold can also be set to other multiples of the rated capacity of the battery, compared with the setting of 0.02 times (0.02C) of the rated capacity of the battery in the present application, it cannot reach the best balance point, and can neither ensure that the battery is in a light load state nor minimize the impact on the open circuit voltage measured after the voltage is stabilized.

[0060] In addition, by setting the recovery time threshold in the present application, it can be ensured that the battery has enough time to stabilize in its new working state after the current value is lower than the preset current threshold for the first time. This can avoid erroneous judgment of the battery state due to short-term fluctuations in current, thereby improving the response accuracy of the battery management system and the stability of battery performance. It can be understood that the setting of the recovery time threshold is also creatively discovered and obtained by the inventor of the present application after a series of experiments. It can be used to determine the shortest time required for the battery to transition from one state to another. Next, the process of determining the recovery time threshold will be described in detail in this application.

[0061] Furthermore, since the electromotive force (open circuit voltage) of a lead-acid battery is a function of the electrolyte density, where the electrolyte density decreases proportionally with the continued discharge of the battery, there is good linearity between the open circuit voltage (electromotive force) and the state of charge of the lead-acid battery. In this way, a linear function can be fitted according to the types of different target batteries to calculate the state of charge of different target batteries at different open circuit voltages. However, this calculation method requires the lead-acid battery to maintain a small operating current (light load state) and continue to operate at a small operating current for a period of time before an accurate open circuit voltage can be measured.

[0062] Based on the above method, when the current value of the target battery is less than the preset current threshold, it is determined that the target battery maintains a smaller operating current (light load state) at the current moment, and the duration of the target battery in the smaller operating current (recovery time threshold) is judged. The recovery time threshold needs to be specifically determined by performing multiple cycles of repetitive pulse discharge experiments on the target battery.

[0063] Among them, the repetitive pulse discharge experiment of multiple cycles on the target battery can perform continuous discharge without interrupting the target battery, and there is no need to keep the target battery stationary. The corresponding relationship between the open circuit voltage value and the duration of each cycle can be obtained, and then the functional relationship between the charge state and the open circuit voltage of the target battery and the recovery time threshold of the target battery can be determined by performing discharge analysis on multiple cycles and any cycle.

[0064] Figure 3 A flow chart of an exemplary repetitive pulse discharge experiment according to an embodiment of the present application is shown.

[0065] like Figure 3 As shown in , in the embodiment of the present application, determining the recovery time threshold by performing multiple cycles of repetitive pulse discharge experiments on the target battery in advance further includes the following steps.

[0066] In step 10, based on a preset discharge rate, a target battery in a fully charged state is subjected to multiple cycles of repetitive pulse discharge; wherein, in each cycle, the target battery is controlled to discharge according to a first preset time, and after the discharge is completed, the target battery is controlled to stand still according to a second preset time, so that the target battery's corresponding discharge power ratio in each cycle reaches a preset proportion value.

[0067] In an embodiment of the present application, the preset discharge rate, the first preset time and the second preset time can be specifically set according to the battery parameters of the target battery and the experimental requirements of repetitive pulse discharge; the discharge power proportion corresponding to each cycle can be specifically determined by calculation according to the preset discharge rate and the first preset time.

[0068] As an example of performing multiple cycles of repetitive pulse discharge experiments on a target battery, a lead-acid battery in a fully charged state (with a charge state value of 100%) is prepared in a laboratory to perform multiple cycles of repetitive pulse discharge experiments on the lead-acid battery. The discharge rate of the charge-discharge experiment is set to 0.15C, the discharge time (first preset time) is set to 20 minutes, and the standing time (second preset time) is set to 1 hour. At this time, the discharge power corresponding to each cycle accounts for 5%; multiple cycles of discharge are repeated until the discharge is terminated, and the point where the battery voltage drops significantly is taken as the point corresponding to the battery's charge state of 0.

[0069] Figure 4 FIG. 1 shows a schematic diagram of the relationship between the port voltage and the power-on duration of an exemplary target battery according to an embodiment of the present application. Figure 4 The figure shows, by way of example, a curve showing the relationship between the terminal voltage and the power-on duration of a target battery obtained by performing a repetitive pulse discharge experiment on the target battery for multiple cycles.

[0070] like Figure 4 As shown in the figure, the relationship curve between the port voltage and the power-on duration of the target battery is shown in the form of a solid line in the plane coordinate system, and the vertical axis of the plane coordinate system represents the port voltage of the target battery; the horizontal axis of the plane coordinate system represents the power-on duration of the target battery, which is the duration of the repetitive pulse discharge experiment.

[0071] Furthermore, for the recovery time of the battery voltage after charge and discharge, any cycle can be selected from multiple cycles, and the recovery time threshold of the target battery when determining the state of charge value can be determined by analyzing the rebound curve of the target battery during discharge.

[0072] Figure 5 FIG2 shows a second schematic diagram of the relationship between the port voltage and the power-on duration of an exemplary target battery according to an embodiment of the present application. Figure 5 The relationship curve between the terminal voltage and the power-on duration of the target battery in a certain cycle obtained by performing a repetitive pulse discharge experiment on the target battery for multiple cycles is exemplified.

[0073] like Figure 5 As shown in , the pulse discharge of the target battery in a certain cycle can be divided into four stages: stage a to b represents the moment when the target battery is discharging, at this time, the port voltage of the target battery will instantly drop; stage b to c represents the target battery is in the discharge stage, with the increase of discharge power, the port voltage of the target battery will gradually decrease; stage c to d represents the moment when the target battery ends discharge, the battery port voltage will instantly rebound significantly; stage d to e represents that the port voltage of the target battery gradually returns to a stable state.

[0074] Here, since the recovery time of the target battery after discharge is mainly in the d to e stage, the time in the d to e stage is generally longer, wherein the recovery time in the later stage of this stage is longer, but the port voltage recovery in this stage is not obvious, therefore, it can be reduced according to the proportional value to improve the resource utilization of the system.

[0075] Further, such as Figure 3 As shown in , the recovery time threshold of the target battery is specifically determined through the following steps.

[0076] In step 20, for a target cycle among the multiple cycles, the discharge completion time and the rest completion time of the target battery in the target cycle are determined, and the port voltage value corresponding to each time between the discharge completion time and the rest completion time of the target battery is obtained.

[0077] In step 30, a first port voltage value corresponding to the standing completion moment is subtracted from a second port voltage value corresponding to the discharge completion moment to obtain a first difference result, and the first difference result is reduced according to a second preset ratio value to obtain a reduction result, so as to determine the reduction result as the recovery voltage value corresponding to the target battery in the target cycle.

[0078] In step 40, the time corresponding to the recovery voltage value is subtracted from the discharge completion time to obtain a second difference result, and the second difference result is determined as the recovery time threshold of the target battery.

[0079] In the embodiment of the present application, the target cycle refers to any cycle of multiple cycles of repetitive pulse discharge on the target battery; the second preset ratio value can be set to 95%, or can be specifically set according to the battery parameters of the target battery and the experimental requirements of repetitive pulse discharge.

[0080] like Figure 5 As shown in , exemplarily, assuming that the second preset ratio value is set to 95%, first, determine that the discharge completion time of the target battery in the target cycle is the time corresponding to point a, and the standing completion time is the time corresponding to point e, and obtain the port voltage value corresponding to each time between the time corresponding to point a and the time corresponding to point e; then, the port voltage value corresponding to point e is subtracted from the port voltage value corresponding to point d to obtain a first difference result, and the first difference result is reduced by 95% to determine the reduction result as the recovery voltage value corresponding to the target battery in the target cycle; finally, determine the time corresponding to the point in the stage curve from d to e of the recovery voltage value, subtract the time from the time corresponding to point d, and determine the obtained second difference result as the recovery time threshold of the target battery.

[0081] In summary, by conducting repetitive pulse discharge experiments on the target battery, the relationship between the port voltage and the power-on duration of the target battery in multiple cycles in the experiment is obtained, and the relationship between the open circuit voltage and the state of charge of the target battery is further obtained. For the four discharge stages of the target cycle in multiple cycles, the recovery time threshold of the target battery is determined through the rebound mechanism of discharge recovery.

[0082] Furthermore, by performing repeated pulse discharge experiments on the target battery, the relationship between the open circuit voltage and the state of charge of the target battery can be further obtained, and the calculation formula for the relationship between the open circuit voltage and the state of charge of the target battery can be determined by curve fitting.

[0083] like Figure 3 As shown in , the relationship calculation formula between the open circuit voltage and the state of charge is predetermined by the following steps.

[0084] In step 50, in response to the target battery's state of charge being converted to a dead state during the repetitive pulse discharge process, a third port voltage value corresponding to the start time of each cycle of the target battery is obtained, and the third port voltage value is determined as the open circuit voltage value corresponding to the start time of each cycle.

[0085] In step 60, based on the fact that the proportion of the discharged electricity corresponding to each cycle is a preset proportion value, the state of charge value corresponding to the start time of each cycle is determined.

[0086] In the embodiment of the present application, since no current passes through the target battery in the experiment at the moment of discharge (open circuit state), the port voltage (third port voltage value) of the target battery at the moment of discharge (the starting moment of each cycle) is equal to the open circuit voltage value; in addition, since the discharge power proportion (preset proportion value) corresponding to each cycle is consistent, the charge state values ​​corresponding to the target battery at the starting moment and the ending moment of each cycle can be determined.

[0087] Here, it should be noted that due to the long service life of the target battery and the complexity of the actual use environment, the current rated state of charge value of the target battery will be reduced relative to the rated state of charge value when it leaves the factory. Figure 4 As shown in , theoretically, a repetitive pulse test with 20 cycles can be performed on the target battery. However, in actual tests, the number of cycles of the repetitive pulse test is generally less than 20 times. However, the discharge power ratio (preset ratio value) corresponding to each cycle of the repetitive pulse test remains unchanged, and only affects the target battery at the current rated state of charge value.

[0088] Based on this, it is understandable that Figure 4The dotted line shown in can represent the relationship curve between the open circuit voltage and the state of charge of the target battery in the repetitive pulse discharge experiment.

[0089] In step 70 , a linear relationship between the open circuit voltage value and the state of charge value is determined based on the open circuit voltage value and the state of charge value.

[0090] In step 80, a curve fitting is performed on the linear relationship using a high-order function fitting method, and the obtained fitting result is determined as a calculation formula for the relationship between the open circuit voltage and the state of charge.

[0091] In the embodiment of the present application, since the relationship curve between the open circuit voltage and the state of charge of the target battery is generally a linear relationship close to a linear function, but the relationship curve is not accurately expressed using a linear relationship, a higher-order function can be used to fit the linear relationship to obtain a more accurate relationship curve to determine the relationship calculation formula between the open circuit voltage and the state of charge.

[0092] Exemplarily, assuming that a cubic function is used to fit the linear relationship, the calculation formula for determining the relationship between the open circuit voltage and the state of charge is as follows.

[0093] SOC(V)=aV 3 +bV 2 +cV+d.

[0094] Wherein, SOC(V) is the state of charge value corresponding to the open circuit voltage value of the target battery; V is the open circuit voltage value of the target battery; a, b, c and d are constants after fitting, respectively.

[0095] Here, the open circuit voltage values ​​of the target battery at different state of charge values ​​may be collected, and the fitted constants including a, b, c and d may be determined by a curve fitting method such as the least square method.

[0096] In summary, by conducting repetitive pulse discharge experiments on the target battery, the open circuit voltage of the target battery can be further collected after the current value of the target battery is small and lasts for a period of recovery time, that is, the open circuit voltage of the battery is measured by the open circuit voltage method, so as to accurately determine the functional relationship between the state of charge and the open circuit voltage of the target battery by curve fitting.

[0097] like Figure 1 As shown in, in step S300, in response to the current value and the power-on duration both satisfying preset conditions, based on the port voltage value, a first state of charge value of the target battery at the current moment is determined using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge.

[0098] In some embodiments, the determining of the first state of charge value of the target battery at the current moment based on the port voltage value and using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge may further include the following steps.

[0099] In step S301, based on the port voltage value, a third state of charge value of the target battery at the current moment is obtained by using a predetermined relationship calculation formula between the open circuit voltage and the state of charge.

[0100] In step S302, it is determined whether the third state of charge value is less than the fourth state of charge value of the target battery at the previous moment.

[0101] In an embodiment of the present application, the port voltage value of the target battery at the current moment is input into the relationship calculation formula between the road voltage and the state of charge to obtain the third state of charge value of the target battery at the current moment, and it is further determined whether the third state of charge value is less than the fourth state of charge value of the target battery at the previous moment.

[0102] The third state of charge value refers to the target battery and state of charge value calculated using a predetermined open circuit voltage and state of charge relationship calculation formula; the fourth state of charge value refers to the state of charge value of the target battery at the previous moment.

[0103] Here, by comparing the third state of charge value calculated at the current moment with the fourth state of charge value at the previous moment, the state of charge value is corrected if the state of charge value of the target battery has a large deviation due to some reason, so as to improve the user experience.

[0104] In step S303, if the third SOC value is less than the fourth SOC value, the third SOC value is subtracted from the SOC correction value corresponding to the power-on duration, and the obtained difference result is determined as the first SOC value of the target battery at the current moment.

[0105] In step S304, if the third SOC value is greater than or equal to the fourth SOC value, the third SOC value is added to the SOC correction value corresponding to the power-on duration, and the accumulated result is determined as the first SOC value of the target battery at the current moment.

[0106] Here, as the power-on duration increases, the deviation of the target battery will gradually increase. Therefore, it is necessary to determine the corresponding state of charge correction value based on the power-on duration.

[0107] In the embodiment of the present application, the third state of charge value of the target battery is made to approach the fourth state of charge value at a speed of slope K, so that the state of charge correction value is obtained as the product of slope K and power-on duration.

[0108] In this way, for the case where the third state of charge value is less than the fourth state of charge value, the third state of charge value is subtracted from the state of charge correction value, and for the case where the third state of charge value is greater than or equal to the fourth state of charge value, the third state of charge value is added to the state of charge correction value to finally obtain the first state of charge value of the target battery at the current moment.

[0109] like Figure 2 As shown in , the determination method further includes the following steps.

[0110] In step S500, in response to at least one of the current value and the power-on duration not satisfying a preset condition, an initial state of charge value of the target battery at the beginning of a power-on operation and a rated capacity value of the target battery are acquired.

[0111] It should be noted that since the ampere-hour integration method is a commonly used method to determine the state of charge value, this method requires a complete charging and discharging process of a battery to be learned, and the charging and discharging current during the learning process needs to be in a certain range to obtain a relatively accurate state of charge value.

[0112] In addition, considering that it is difficult to frequently estimate the complete charging and discharging process of the battery in actual usage scenarios, the ampere-hour integration method cannot accurately obtain the state of charge value of the battery at the initial moment. On the other hand, since the battery management system has certain errors in current sampling, the error accumulation caused by long-term sampling will also make the determined state of charge value less accurate.

[0113] Based on this, when the target battery has a large charge and discharge current, the error in obtaining the state of charge value and the charge and discharge current of the battery at the initial moment is small, and the fifth state of charge value of the target battery at the current moment is determined using the ampere-hour integration method, thereby improving the accuracy and efficiency of determining the state of charge value.

[0114] In step S600, based on the current value, the power-on duration, the initial state of charge value and the rated capacity value, a fifth state of charge value of the target battery at the current moment is determined using a preset integral calculation formula.

[0115] In the embodiment of the present application, the expression of the preset integral calculation formula is as follows.

[0116]

[0117] Among them, SOC(t) is the fifth state of charge value of the target battery at the current moment; SOC (O) is the initial state of charge value of the target battery when it starts to power on; t is the power-on duration; Cn is the rated capacity value of the target battery; I bat is the current value after the target battery is powered on. When the target battery is discharged, I bat is negative, when the target battery is charging, I bat Is positive.

[0118] The method for determining the state of charge provided in the embodiment of the present application confirms that the battery is not in a serious power-deficient state when the target battery starts to power on, and further determines whether the current value and power-on duration of the target battery obtained at the current moment both meet preset conditions. When it is determined that both preset conditions are met, the state of charge value of the target battery at the current moment is determined based on the port voltage value of the target battery and by utilizing the relationship between the open circuit voltage and the state of charge determined in advance. In this way, the problems of excessive complexity and large limitations in determining the state of charge of the battery are avoided, thereby improving the accuracy of determining the state of charge of the battery.

[0119] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0120] Based on the same technical concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a device 600 for determining a state of charge.

[0121] Figure 6 FIG. 1 is a schematic diagram showing a structure of an exemplary device for determining a state of charge according to an embodiment of the present application. Figure 6 , the determining device 600 comprises:

[0122] The first judgment module 610 is used for obtaining a port voltage value of the target battery at a current moment in response to the target battery starting to power on, and judging whether the port voltage value is greater than a preset voltage threshold of the target battery;

[0123] A second judgment module 620 is used to obtain the current value and power-on duration of the target battery at the current moment in response to the port voltage value being greater than the preset voltage threshold, and to judge whether the current value and the power-on duration both meet preset conditions;

[0124] The value determination module 630, in response to the current value and the power-on duration both satisfying preset conditions, determines the first state of charge value of the target battery at the current moment based on the port voltage value and using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge.

[0125] For the convenience of description, the above device is described in terms of functions divided into various modules. Of course, when implementing the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0126] The device of the above embodiment is used to implement the corresponding method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0127] Based on the same technical concept, corresponding to any of the above-mentioned embodiments, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in any of the above embodiments when executing the program.

[0128] Figure 7 A schematic diagram of the structure of an exemplary electronic device according to an embodiment of the present application is shown, and the device may include: a processor 710, a memory 720, an input / output interface 730, a communication interface 740, and a bus 750. The processor 710, the memory 720, the input / output interface 730, and the communication interface 740 are connected to each other in communication within the device through the bus 750.

[0129] The processor 710 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0130] The memory 720 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 720 may store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program codes are stored in the memory 720 and are called and executed by the processor 710.

[0131] The input / output interface 730 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0132] The communication interface 740 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through a wired mode (such as USB, network cable, etc.) or a wireless mode (such as mobile network, WIFI, Bluetooth, etc.).

[0133] The bus 750 comprises a pathway that transmits information between the various components of the device (eg, the processor 710 , the memory 720 , the input / output interface 730 , and the communication interface 740 ).

[0134] It should be noted that, although the above device only shows the processor 710, the memory 720, the input / output interface 730, the communication interface 740 and the bus 750, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0135] The electronic device of the above embodiment is used to implement the corresponding method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0136] Based on the same technical concept, corresponding to any of the above-mentioned embodiments, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the method described in any of the above embodiments.

[0137] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be achieved by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0138] The computer instructions stored in the storage medium of the above embodiments are used to enable the computer to execute the method described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0139] Based on the same inventive concept, corresponding to the method described in any of the above embodiments, the present application also provides a computer program product, including computer program instructions, which, when executed on a computer, enable the computer to execute the method described in any of the above embodiments. In some embodiments, the computer program instructions may be executed by one or more processors of a computer so that the computer and / or the processor execute the method. Corresponding to the execution subject corresponding to each step in each embodiment of the method, the processor that executes the corresponding step may belong to the corresponding execution subject.

[0140] The computer program product of the above embodiment is used to enable the computer and / or the processor to execute the method described in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described in detail here.

[0141] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0142] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power supply / ground connection with the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform to be implemented in the embodiments of the present application (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details (e.g., circuits) to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0143] Although the present application has been described in conjunction with specific embodiments of the present application, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0144] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A method for determining a state of charge, characterized in that: The determination method comprises: In response to the target battery starting to power on, obtaining a port voltage value of the target battery at a current moment, and determining whether the port voltage value is greater than a preset voltage threshold of the target battery; In response to the port voltage value being greater than the preset voltage threshold, respectively obtaining the current value and the power-on duration of the target battery at the current moment, and determining whether both the current value and the power-on duration meet preset conditions; In response to the current value and the power-on duration both satisfying preset conditions, based on the port voltage value, a first state of charge value of the target battery at the current moment is determined using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge.

2. The method according to claim 1, characterized in that The method further comprises: In response to the port voltage value being less than or equal to the preset voltage threshold, based on a mapping relationship between the open circuit voltage and the state of charge of the target battery, a preset value is determined as a second state of charge value of the target battery at the current moment.

3. The method according to claim 1, characterized in that The following steps are used to determine whether the current value and the power-on duration both meet the preset conditions: Determining whether the current value is less than a preset current threshold; If the current value is less than the preset current threshold, then based on the power-on duration, determine the duration of the current moment relative to the moment corresponding to the first time the current value is less than the preset current threshold, and determine whether the duration is greater than a predetermined recovery time threshold of the target battery; If the duration is greater than the recovery time threshold, it is determined that both the current value and the power-on duration satisfy a preset condition.

4. The method according to claim 3, characterized in that The recovery time threshold is predetermined by the following steps: Based on a preset discharge rate, a target battery in a fully charged state is subjected to multiple cycles of repetitive pulse discharge; wherein, in each cycle, the target battery is controlled to be discharged according to a first preset time, and after the discharge is completed, the target battery is controlled to be stationary according to a second preset time, so that the target battery has a discharge power proportion corresponding to each cycle that reaches a preset proportion value; For a target cycle among the multiple cycles, determining a discharge completion time and a rest completion time of the target battery in the target cycle, and obtaining a port voltage value of the target battery corresponding to each time between the discharge completion time and the rest completion time; Subtracting the first port voltage value corresponding to the rest completion time from the second port voltage value corresponding to the discharge completion time to obtain a first difference result, and reducing the first difference result according to a second preset ratio value to obtain a reduction result, so as to determine the reduction result as the recovery voltage value corresponding to the target battery in the target cycle; The time corresponding to the recovery voltage value is subtracted from the discharge completion time to obtain a second difference result, and the second difference result is determined as the recovery time threshold of the target battery.

5. The method according to claim 4, characterized in that The relationship between the open circuit voltage and the state of charge is determined in advance by the following steps: In response to the state of charge of the target battery being converted into a dead state during the repetitive pulse discharge process, obtaining a third port voltage value of the target battery corresponding to the start time of each cycle, and determining the third port voltage value as the open circuit voltage value corresponding to the start time of each cycle; Based on the proportion of the discharged electricity corresponding to each cycle being a preset proportion value, determining the state of charge value corresponding to the starting time of each cycle; Based on the open circuit voltage value and the state of charge value, determining a corresponding linear relationship between the open circuit voltage value and the state of charge value; The linear relationship is fitted by curve fitting using a high-order function fitting method, and the obtained fitting result is determined as a calculation formula for the relationship between the open circuit voltage and the state of charge.

6. The method according to claim 1, characterized in that The determining, based on the port voltage value, of a first state of charge value of the target battery at the current moment by using a predetermined calculation formula for the relationship between the open circuit voltage and the state of charge comprises: Based on the port voltage value, using a predetermined relationship calculation formula between the open circuit voltage and the state of charge, obtaining a third state of charge value of the target battery at the current moment; Determining whether the third state of charge value is less than a fourth state of charge value of the target battery at a previous moment; If the third state of charge value is less than the fourth state of charge value, subtract the third state of charge value from the state of charge correction value corresponding to the power-on duration, and determine the obtained difference result as the first state of charge value of the target battery at the current moment; If the third SOC value is greater than or equal to the fourth SOC value, the third SOC value is added to the SOC correction value corresponding to the power-on duration, and the accumulated result is determined as the first SOC value of the target battery at the current moment.

7. The method according to claim 1, characterized in that The method further comprises: In response to at least one of the current value and the power-on duration not satisfying a preset condition, acquiring an initial state of charge value of the target battery when a power-on operation starts, and a rated capacity value of the target battery; Based on the current value, the power-on duration, the initial state of charge value and the rated capacity value, a fifth state of charge value of the target battery at the current moment is determined using a preset integral calculation formula.

8. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions, wherein the computer instructions are used to cause a computer to execute the method according to any one of claims 1 to 7.

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