Calibration method and energy storage device

Abstract

The invention discloses a calibration method and energy storage equipment, and relates to the technical field of energy storage, the calibration method is used for a battery pack, and the calibration method comprises the steps: determining an electric quantity compensation coefficient based on the voltage change trend of the battery pack under the condition that the current voltage of the battery pack is located in a preset electric quantity compensation range; and determining the remaining power based on the power compensation coefficient and the current power. The electric quantity compensation coefficient is determined based on the change trend of the voltage of the battery pack, that is, the electric quantity compensation coefficient is dynamically determined according to the actual voltage change condition of the battery pack instead of depending on the detected current value, that is, the conditions that the battery pack is affected by aging, temperature and internal electrochemical reaction are all considered by calibration, and the calibration accuracy is improved. Therefore, the more accurate remaining capacity of the battery pack is obtained, and the calculation precision of the remaining capacity is improved.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, and more specifically, to a calibration method and an energy storage device. Background Art

[0002] Currently, the battery management system (BMS) of a battery (the BMS is the center for managing and monitoring power batteries and is used to manage, maintain, and monitor each module of the battery) generally calculates the remaining capacity percentage (State of Charge, SOC) of the battery by the Coulomb Counting method.

[0003] Since the Coulomb Counting method relies on accurate current measurement, and the accuracy and stability of current sensors are often limited, errors exist in the current measurement process, resulting in difficulty in ensuring the accuracy of the SOC. Summary of the Invention

[0004] Embodiments of this application provide a calibration method and an energy storage device, which can solve at least one of the above technical problems.

[0005] This application proposes a calibration method for a battery pack. The method includes: when the current voltage of the battery pack is within a preset power compensation range, determining a power compensation coefficient based on the voltage change trend of the battery pack; and determining the remaining power based on the power compensation coefficient and the current power.

[0006] This application also proposes a battery pack, a controller, a memory; and a computer program, where the computer program is stored in the memory and executed by the controller, and the computer program includes instructions for executing the calibration method of any embodiment.

[0007] This application also proposes an energy storage device, which includes a battery pack and a controller; and a computer program, where the computer program is stored in the controller and executed by the controller, and the computer program includes instructions for executing the calibration method of any embodiment.

[0008] This application also proposes a non-volatile computer-readable storage medium. When the computer program is executed by the controller, the controller is caused to execute the calibration method of any embodiment.

[0009] The calibration method and energy storage device according to the embodiments of the present application, when the current voltage of the battery pack is within the preset power compensation range, determine the power compensation coefficient based on the change trend of the voltage of the battery pack, and then determine the remaining power based on the power compensation coefficient and the current power. Since the power compensation coefficient is determined based on the change trend of the voltage of the battery pack, that is, dynamically determined according to the actual voltage change of the battery pack, rather than relying on the detected current value, that is, the situations of the battery pack being affected by aging, temperature and internal electrochemical reactions are all taken into account in the calibration, so as to obtain a more accurate remaining power of the battery pack and improve the calculation accuracy of the remaining power; in other words, the power compensation coefficient dynamically determined based on the change trend of the voltage of the battery pack can adapt to the calibration amount required by the battery pack under different working conditions and different environments, and improve the applicability, reliability of the calibration method and the accuracy of the remaining power after calibration.

[0010] In addition, the calibration method according to the embodiments of the present application adjusts the power compensation coefficient based on the change trend of the voltage of the battery pack, and can be adapted to different types of battery packs (such as lithium batteries, lithium iron phosphate batteries, etc.), and can further improve the adaptability and universality of the calibration method.

[0011] The additional aspects and advantages of the embodiments of the present application will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

[0013] Figure 1 is a schematic diagram of the scenario where the calibration method of some embodiments of the present application is applied to the battery pack of the energy storage device;

[0014] Figure 2 is a schematic flow chart of the calibration method of some embodiments of the present application;

[0015] Figure 3 is a schematic flow chart of the calibration method of some embodiments of the present application;

[0016] Figure 4 is a schematic flow chart of the calibration method of some embodiments of the present application;

[0017] Figure 5 is a schematic flow chart of the calibration method of some embodiments of the present application;

[0018] Figure 6 is a schematic flow chart of the calibration method of some embodiments of the present application;

[0019] Figure 7It is a schematic flowchart of a calibration method according to some embodiments of the present application;

[0020] Figure 8 It is a schematic flowchart of a calibration method according to some embodiments of the present application;

[0021] Figure 9 It is a schematic flowchart of a calibration method according to some embodiments of the present application;

[0022] Figure 10 It is a schematic flowchart of a calibration method according to some embodiments of the present application;

[0023] Figure 11 It is a schematic diagram of modules of a calibration device according to some embodiments of the present application;

[0024] Figure 12 It is a schematic diagram of the connection state of a non - volatile computer - readable storage medium and a processor according to some embodiments of the present application. Specific Embodiments

[0025] The following details the embodiments of the present application. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application and should not be construed as a limitation to the embodiments of the present application.

[0026] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one feature. In the description of the present application, "a plurality" means at least two, such as two, three, unless otherwise clearly and specifically defined.

[0028] For the convenience of understanding the present application, the related technologies of the present application are introduced below:

[0029] During the use of a battery, monitoring the remaining capacity percentage (State of Charge, SOC) of the battery is crucial for the charging and discharging status and safety of the battery.

[0030] The battery management system (BMS) of the battery (the BMS is the central hub for managing and monitoring power batteries, used to manage, maintain, and monitor each module of the battery) can calculate the SOC of the battery through the Coulomb Counting method and display it on the display screen of the battery.

[0031] Since the Coulomb Counting method relies on accurate current measurement, and the accuracy and stability of current sensors are often limited, errors exist in the current measurement process, and the errors accumulate continuously, resulting in a gradual decrease in the accuracy of the obtained SOC over time.

[0032] Moreover, during the use of the battery, the battery will gradually age, resulting in a gradual attenuation of the battery capacity, and the internal resistance of the aged battery will increase. The charging and discharging efficiency of the aged battery under the same current will change. The Coulomb Counting method does not consider the impact brought by the change in charging and discharging efficiency when calculating the SOC. And since the Coulomb Counting method usually relies on accurate current measurement, both the attenuated battery capacity and the increased internal resistance lead to an increase in current detection errors, which will also affect the accuracy of the Coulomb Counting method.

[0033] Furthermore, the performance of the battery is significantly affected by temperature. At low temperatures, the internal resistance of the battery will increase, resulting in an increase in current measurement errors; at high temperatures, the aging speed of the battery will accelerate, which also affects the internal resistance, battery capacity, and charging and discharging efficiency of the battery.

[0034] In addition, the Coulomb Counting method simplifies the complex chemical reaction process of the battery and ignores the non-linear characteristics of the electrochemical reactions inside the battery, further resulting in inaccurate estimation results.

[0035] Therefore, during the battery charging process, it may occur that after the voltage of the battery approaches the charging cut-off voltage, the battery stops charging, but at this time the displayed SOC is still a relatively low value (not reaching the SOC value corresponding to full charge (such as 100%)). During the discharging process, it may occur that after the voltage of the battery approaches the discharging cut-off voltage, the battery stops discharging, but at this time the displayed SOC is still a relatively high value, resulting in misjudgment of the user about the usage situation of the battery and affecting the user experience.

[0036] To solve the above technical problems, the embodiments of the present application provide a calibration method, which can be applied to an energy storage device 1000 including a battery pack 100 to calibrate the SOC of the battery pack 100.

[0037] Optionally, the energy storage device 1000 includes a battery pack 100 and a controller 101, and the controller 101 can be used to execute the calibration method.

[0038] Optionally, the energy storage device 1000 may further include a memory 102, and the memory 102 can be used to store a preset power compensation range, a power compensation coefficient, etc.

[0039] Optionally, the energy storage device 1000 includes a display screen 103, and after obtaining the calibrated SOC through the calibration method, it can be displayed on the display screen 103.

[0040] Optionally, the battery pack 100 includes one or more battery cells, and the multiple battery cells can be connected in series and / or in parallel to realize the charge and discharge of the battery pack 100.

[0041] Next, taking the calibration method applied to the battery pack of the energy storage device as an example, the calibration method of the embodiment of the present application will be elaborated in detail:

[0042] Please refer to Figure 1 and Figure 2 , the calibration method of the embodiment of the present application includes:

[0043] Step 011: When the current voltage of the battery pack is within the preset power compensation range, determine the power compensation coefficient based on the voltage change trend of the battery pack.

[0044] Among them, the preset power compensation range can correspond to the voltage condition of the battery pack at the end of charge and discharge, and within the preset power compensation range, the correlation between the voltage change and the power change of the battery pack is relatively high. The preset power compensation range can also be adaptively set according to the characteristics of the battery, the use environment, the load condition, etc.

[0045] Please refer to Figure 3 , optionally, the preset power compensation range includes a first preset voltage threshold and a second preset voltage threshold, the first preset voltage threshold is greater than the second preset voltage threshold, and the calibration method further includes:

[0046] Step 013: When the battery pack is in the charging condition and the current voltage of the battery pack is greater than the first preset voltage threshold, determine that the current voltage of the battery pack is within the preset power compensation range;

[0047] Step 014: When the battery pack is in the discharging condition and the current voltage of the battery pack is less than the second preset voltage threshold, determine that the current voltage of the battery pack is within the preset power compensation range.

[0048] Among them, when the battery pack is in the charging condition and the current voltage of the battery pack is greater than the first preset voltage threshold, it can be considered that the battery pack enters the end of charging (that is, the battery pack is close to the fully charged state). When the battery pack is in the discharging condition and the current voltage of the battery pack is less than the second preset voltage threshold, it can be considered that the battery pack enters the end of discharging (that is, the battery pack is close to the fully discharged state). For example, taking the case where the voltage of the battery pack is 0 volts (V) when the battery pack is in the deep discharge state and the voltage of the battery pack is 4.2V when it is charged to the fully charged state as an example, assuming that during the charging process of the battery pack, the voltage range from 3.5V to 4.2V is the preset power compensation range, the first preset voltage threshold can be 3.5V. When the battery pack is in the charging condition, by comparing whether the current voltage of the battery pack is greater than 3.5V, it can be determined whether the current voltage of the battery pack is within the preset power compensation range. Another example, taking the discharging process of the battery pack from the fully charged state (the voltage of the battery pack is 4.2V) to the deep discharge state (the voltage of the battery pack is 0V) as an example, assuming that during the discharging process of the battery pack, the voltage range from 2.5V to 0V is the preset power compensation range, and the second preset voltage threshold is 2.5V. When the battery pack is in the discharging condition, by comparing whether the current voltage of the battery pack is less than 2.5V, it can be determined whether the current voltage of the battery pack is within the preset power compensation range. In this way, according to the condition of the battery pack and the comparison between the current voltage of the battery pack and the first preset voltage threshold or the second voltage preset threshold, it can be determined whether the current voltage of the battery pack is within the preset power compensation range.

[0049] Among them, the power compensation coefficient can be used to compensate and calibrate the SOC calculated by the BMS of the battery pack according to the ampere-hour integration method, so that the calibrated SOC can accurately reflect the true power of the battery pack.

[0050] Specifically, when the current voltage of the battery pack is within the preset power compensation range (for example, the preset power compensation range can include voltage thresholds corresponding to different conditions. According to the condition of the battery pack and the corresponding voltage threshold, it can be determined whether the current voltage is within the preset power compensation range), by obtaining the change trend of the voltage of the battery pack (for example, the voltage of the battery pack increases with time and the increase amplitude is greater than a certain amplitude threshold, etc.), the calibration value required for calibrating the SOC, that is, the power compensation coefficient, is determined.

[0051] Step 012: Determine the remaining power based on the power compensation coefficient and the current power.

[0052] Among them, the remaining power can accurately reflect the proportion of the remaining power of the battery pack relative to the total capacity of the battery pack, that is, the SOC.

[0053] Specifically, the current battery level can be the SOC of the battery pack obtained by the BMS based on the ampere-hour integration method before the current voltage of the battery pack enters the preset battery level compensation range. After determining the battery level compensation coefficient based on the change trend of the battery pack voltage, the current battery level can be corrected and calibrated according to the battery level compensation coefficient, so as to compensate for the estimation error in the process of estimating the SOC and provide and display a more accurate remaining battery level to the user.

[0054] Please refer to Figure 4 , in some embodiments, the calibration method further includes:

[0055] Step 015: Update the current displayed battery level of the battery pack based on the remaining battery level.

[0056] Wherein, the current displayed battery level can be the SOC estimated by the BMS of the battery pack based on the ampere-hour integration method and displayed on the display screen of the battery pack. After calibrating the current battery level with the battery level compensation coefficient to obtain the remaining battery level, the current displayed battery level of the battery pack can be updated based on the remaining battery level, so that the user can obtain the remaining battery level situation that matches the actual remaining capacity of the battery pack.

[0057] Please refer to Figure 5 and Figure 6 , optionally, Step 015: Update the current displayed battery level of the battery pack based on the remaining battery level, including:

[0058] Step 0151: When the working condition of the battery pack is the charging condition and the remaining battery level is less than the current displayed battery level, display the current displayed battery level;

[0059] Step 0152: When the working condition of the battery pack is the charging condition and the remaining battery level is greater than the current displayed battery level, display the remaining battery level;

[0060] Step 0153: When the working condition of the battery pack is the discharging condition and the remaining battery level is greater than the current displayed battery level, display the current displayed battery level;

[0061] Step 0154: When the working condition of the battery pack is the discharging condition and the remaining battery level is less than the current displayed battery level, display the remaining battery level.

[0062] It can be understood that when the battery pack is in the charging condition, the power of the battery pack gradually increases, and the SOC displayed on the display screen of the battery pack for the user should also gradually increase. Therefore, when the remaining power after calibration is less than the current displayed power, if the remaining power is displayed at this time (that is, the current displayed power is called back), it may cause the user to misjudge that there is a fault in the battery pack. Moreover, the jump caused by the correction may also affect the user experience. Therefore, the current displayed power can continue to be displayed until the remaining power is greater than the current displayed power, and then the current remaining power is updated and displayed according to the remaining power, so that the user can see the real-time progress during the charging process of the battery pack. Similarly, when the battery pack is in the discharging condition, the power of the battery pack gradually decreases, and the SOC displayed on the display screen of the battery pack for the user should also gradually decrease. Therefore, when the remaining power after calibration is greater than the current displayed power, if the remaining power is displayed at this time (that is, the current displayed power is called back), it may cause the user to misjudge that there is a fault in the battery pack. Therefore, the current displayed power can continue to be displayed until the remaining power is less than the current displayed power, and then the current remaining power is updated and displayed according to the remaining power, so that the user can see the real-time progress during the charging process of the battery pack, so that the displayed SOC can as accurately as possible reflect the current state of the battery and give the user a clear battery state feedback.

[0063] In this way, when the current voltage of the battery pack is within the preset power compensation range, based on the change trend of the voltage of the battery pack, the power compensation coefficient is determined, and then based on the power compensation coefficient and the current power, the remaining power is determined. Since the power compensation coefficient is determined based on the change trend of the voltage of the battery pack, that is, dynamically determined according to the actual voltage change situation of the battery pack, rather than relying on the detected current value, that is, the situations of the battery pack affected by aging, temperature and internal electrochemical reactions are all taken into account in the calibration, so as to obtain a more accurate remaining power of the battery pack and improve the calculation accuracy of the remaining power. In other words, the power compensation coefficient dynamically determined based on the change trend of the voltage of the battery pack can adapt to the calibration amount required by the battery pack under different working conditions and different environments, and improve the applicability, reliability of the calibration method and the accuracy of the remaining power after calibration.

[0064] In addition, the calibration method of the embodiment of the present application adjusts the power compensation coefficient according to the change trend of the voltage of the battery pack, and can adapt to different types of battery packs (such as lithium batteries, lithium iron phosphate batteries, etc.), and can further improve the adaptability and universality of the calibration method.

[0065] Please refer to Figure 7 , in some embodiments, the battery pack includes battery cells, and step 011: determining a power compensation coefficient based on the change trend of the voltage of the battery pack includes:

[0066] Step 0111: Determine the charge compensation coefficient based on the voltage change trend of the battery cell.

[0067] Among them, the battery cell is the basic unit that makes up the battery pack. The battery pack includes one or more battery cells. For example, the battery pack may include only one battery cell; for another example, the battery pack may include multiple battery cells, and the battery cells can be connected in series and / or in parallel to form the battery pack, etc.

[0068] Specifically, the voltage sensors can be used to collect the voltages of the respective battery cells in the battery pack according to a preset time interval (such as 1 second (s), 2 s, etc.). During the charging and discharging process of the battery pack, the states (voltage values) of the battery cells are usually different, and the voltage change trends are also different. When determining the charge compensation coefficient, it can be determined according to the voltage change trend of the battery cell. For example, when the voltages of the respective battery cells are obtained, the target voltage for determining the charge compensation coefficient can be obtained by performing weighted averaging, or calculating the average value, or taking the maximum voltage value, or taking the minimum voltage value, etc. on the voltages of the respective battery cells, and the charge compensation coefficient of the battery pack can be obtained by detecting the change trend of the target voltage.

[0069] Please refer to Figure 8 , in some embodiments, there are multiple battery cells, and Step 0111: Determine the charge compensation coefficient based on the voltage change trend of the battery cells, including:

[0070] Step 01111: Determine the first target voltage among the current voltages of the multiple battery cells and the second target voltage among the current voltages of the multiple battery cells before a first preset duration based on the charge and discharge conditions of the battery pack;

[0071] Step 01112: Determine the voltage change rate based on the first target voltage and the second target voltage;

[0072] Step 01113: Determine the charge and discharge end duration based on the voltage change rate and the cut-off voltage of the battery pack;

[0073] Step 01114: Determine the charge compensation coefficient based on the charge and discharge end duration and the current charge.

[0074] Among them, the first preset duration can be a duration such as 0.5 s, 1 s, 1.5 s, 2 s, etc. For the convenience of description, the first preset duration is taken as 1 s in the embodiments of the present application for illustration.

[0075] Among them, the cut-off voltage can be a voltage threshold set to prevent the battery pack from being overcharged or overdischarged during the charging or discharging process of the battery pack. For example, the cut-off voltage may include a charging cut-off voltage and a discharging cut-off voltage.

[0076] Among them, the charging and discharging end duration can be the duration required for the voltage of the battery pack to change from the first target voltage to the charging cut-off voltage or the discharging cut-off voltage.

[0077] Specifically, the determination methods of the first target voltage (and the second target voltage) are different when the battery pack is in the charging condition and the discharging condition. For example, the preset power compensation range of the battery pack can be determined first according to the charging and discharging condition of the battery pack (that is, the battery pack is in the charging condition or the discharging condition). When the current voltage of the battery pack is within the preset power compensation range, the first target voltage among the current voltages of multiple battery cells at the current moment can be determined (for example, it can be the average value, median, maximum voltage, or minimum voltage of the voltages of multiple battery cells, etc.). Then, the second target voltage among the current voltages of multiple battery cells 1 s ago (that is, before the first preset duration) can be determined (for example, it can be the average value, median, maximum voltage, or minimum voltage of the voltages of multiple battery cells, etc.); further, according to the first target voltage and the second target voltage, the voltage change speed of the battery pack within 1 s can be determined. The voltage change speed can help calculate the duration for the battery pack to end charging and discharging. That is, based on the voltage change speed and the cut-off voltage of the battery pack (the voltage boundary at which the battery pack stops charging and discharging), the charging and discharging end duration required for the battery pack to end charging or discharging can be determined. Finally, according to the charging and discharging end duration and the current power of the battery pack, the power compensation coefficient can be determined.

[0078] Optionally, the charging and discharging condition of the battery pack includes the charging condition, the cut-off voltage includes the charging cut-off voltage. When the charging and discharging condition of the battery pack is the charging condition, the cut-off voltage is the charging cut-off voltage, and the end duration T is determined based on the following formula:

[0079] T = (Vcp - V1) / (V1 - V2)

[0080] Among them, Vcp is the charging cut-off voltage, V1 is the first target voltage, and V2 is the second target voltage.

[0081] Optionally, the first target voltage includes the maximum voltage among the current voltages of multiple battery cells, or the first target voltage includes the average value of the current voltages of multiple battery cells; the second target voltage includes the maximum voltage among the current voltages of multiple battery cells before the first preset duration, or the second target voltage includes the average value of the current voltages of multiple battery cells before the first preset duration.

[0082] It can be understood that when the battery pack includes multiple battery cells, there will be inconsistencies among the multiple battery cells. That is, during the charging process under the same charging conditions, the voltage values among the battery cells will be different. The charging of the battery pack needs to avoid the voltage of any single battery cell exceeding the safe range. Therefore, the maximum value of the voltages of the multiple battery cells can be determined as the first target voltage (or the second target voltage) to avoid overcharging and the like in the single battery cells of the battery pack at the end of charging.

[0083] Moreover, the average value of the current voltages of the multiple battery cells can also be used as the first target voltage (or the second target voltage). The average value can reflect the overall charging state of the battery pack and avoid damage to the battery pack caused by the voltage of some battery cells being too high or too low during the charging process.

[0084] Specifically, taking the first preset duration as the unit time (i.e., 1 second) as an example, by calculating the ratio of the voltage difference (Vcp - V1) between the first target voltage (V1) and the charging cut-off voltage (Vcp) to the voltage difference (V1 - V2) between the first target voltage and the second target voltage, it is determined how many first preset durations (i.e., how many seconds) are required for the voltage of the battery pack to increase to the charging cut-off voltage (i.e., complete the charging of the battery pack) from the moment when the first target voltage is obtained, so as to estimate the time required for the battery pack to complete charging, that is, the charging end duration.

[0085] Optionally, the charge compensation coefficient Qd is determined based on the following formula:

[0086] Qd = (Qr - Qn) / T

[0087] Wherein, Qr is the rated capacity of the battery pack, Qn is the current capacity of the battery pack, and T is the end duration.

[0088] Among them, the rated capacity can be the maximum capacity of the battery pack, and the current capacity can be the actual capacity of the battery pack at the current moment when the first target duration is obtained.

[0089] Specifically, under the charging condition of the battery pack, after determining the charging end duration, the amount of charge (Qr - Qn) that needs to be supplemented for the battery pack to charge from the current capacity (Qn) to the rated capacity (Qr) can be calculated. The end duration T is the duration of the charging process starting from the current moment. The charge compensation coefficient (Qd) determined based on the above formula reflects the amount of charge supplemented by the battery pack per unit time (within the first preset duration).

[0090] Optionally, based on the charge compensation coefficient and the current charge, the remaining charge SOC is determined based on the following formula:

[0091] SOC = ((Qn + Qd) / Qr)*100%

[0092] Among them, Qn is the current capacity of the battery pack, Qd is the charge compensation coefficient, and Qr is the rated capacity of the battery pack.

[0093] Specifically, during the charging process of the battery pack, the current capacity of the battery pack (Qn) plus the charge compensation coefficient (Qd) is the current total capacity of the battery pack (Qn + Qd). Then, based on the percentage of the ratio between the current total capacity of the battery pack (Qn + Qd) and the rated capacity of the battery pack (Qr), the remaining battery charge SOC of the battery pack can be determined.

[0094] In this way, when the battery pack is in the charging condition, the estimated charging end duration can be obtained according to the first target voltage, the second target voltage, and the charging cut-off voltage. Then, based on the charging end duration, the current capacity of the battery pack, and the rated capacity of the battery pack corresponding to the fully charged state, the charge compensation coefficient can be determined. Finally, based on the charge compensation coefficient and the current battery charge, the remaining battery charge can be determined. By introducing the charge compensation coefficient for calibration and compensation to consider the SOC of the battery pack under the charging condition, the accuracy and precision of SOC calculation are effectively improved.

[0095] In some embodiments, the charge and discharge condition includes the discharge condition, and the cut-off voltage includes the discharge cut-off voltage. When the condition of the battery pack is the discharge condition, the cut-off voltage is the discharge cut-off voltage, and the end duration T is determined based on the following formula:

[0096] T = (V1 - Vdp) / (V2 - V1)

[0097] Among them, Vdp is the discharge cut-off voltage, V1 is the first target voltage, and V2 is the second target voltage.

[0098] Optionally, the first target voltage includes the minimum voltage among the current voltages of multiple battery cells, or the first target voltage includes the average value of the current voltages of multiple battery cells; the second target voltage includes the minimum voltage among the current voltages of multiple battery cells before the first preset duration, or the second target voltage includes the average value of the current voltages of multiple battery cells before the first preset duration.

[0099] It can be understood that when the battery pack includes multiple battery cells, there will be inconsistencies among the multiple battery cells. That is, during the charging process under the same charging conditions, the voltage values among the battery cells will be different. For example, if the voltages of some battery cells are relatively low, then after discharging to the minimum voltage of the battery, if the discharging continues, it may cause the voltage of the battery cell to further drop to an over-discharged state, and over-discharge will damage the battery cell. Therefore, in order to protect the safety of the battery pack and prevent the battery cells from being over-discharged, the minimum value of the voltages of the multiple battery cells can be determined as the first target voltage (and the second target voltage) to prevent the battery cell with the minimum voltage value from being damaged by over-discharge and ensure the overall health of the battery pack.

[0100] Moreover, the average value of the current voltages of the multiple battery cells can also be used as the first target voltage (or the second target voltage). The average value can reflect the overall charging state of the battery pack and avoid damage to the battery pack caused by the voltages of some battery cells being too high or too low during the discharging process.

[0101] Specifically, taking the first preset duration as the unit time (i.e., 1 second) as an example, by calculating the ratio of the voltage difference (V1 - Vdp) between the first target voltage (V1) and the discharge cut-off voltage (Vdp) to the voltage difference (V2 - V1) between the first target voltage and the second target voltage, it is determined how many first preset durations (i.e., how many seconds) are required for the voltage of the battery pack to increase to the discharge cut-off voltage (i.e., complete the discharging of the battery pack) from the moment when the first target voltage is obtained, so as to estimate the time required for the battery pack to complete discharging, that is, the discharge end duration.

[0102] Optionally, the charge compensation coefficient Qd is determined based on the following formula:

[0103] Qd = Qn / T,

[0104] where Qn is the current capacity of the battery pack and T is the end duration.

[0105] Among them, the current capacity can be the actual capacity of the battery pack at the current moment when the first target duration is obtained.

[0106] Specifically, under the discharging condition of the battery pack, after determining the discharge end duration, the consumed charge (Qn - 0) of the battery pack from the current capacity (Qn) to being emptied can be calculated. The end duration T is the duration of the discharging process from the current moment. The charge compensation coefficient (Qd) determined based on the above formula reflects the charge consumed by the battery pack per unit time (within the first preset duration).

[0107] Optionally, based on the charge compensation coefficient and the current charge, the remaining charge SOC is determined based on the following formula:

[0108] SOC = ((Qn - Qd) / Qr) * 100%

[0109] Wherein, Qn is the current capacity of the battery pack, Qd is the charge compensation coefficient, and Qr is the rated capacity of the battery pack.

[0110] Specifically, during the discharge process of the battery pack, subtracting the charge compensation coefficient (Qd) from the current capacity (Qn) of the battery pack gives the current remaining capacity (Qn - Qd) of the battery pack. Then, based on the percentage of the ratio between the current total capacity (Qn - Qd) of the battery pack and the rated capacity (Qr) of the battery pack, the current remaining charge SOC of the battery pack can be determined.

[0111] In this way, when the battery pack is in the discharge condition, the estimated discharge end duration can be obtained according to the first target voltage, the second target voltage, and the discharge cut-off voltage. Then, based on the discharge end duration and the current capacity of the battery pack, the charge compensation coefficient is determined. Finally, based on the charge compensation coefficient and the current charge, the remaining charge can be determined. By introducing the charge compensation coefficient for calibration and compensation to consider the SOC of the battery pack in the discharge condition, the accuracy and precision of SOC calculation are effectively improved.

[0112] Please refer to Figure 9 , in some embodiments, the calibration method further includes:

[0113] Step 016: When the battery pack is in the standby state and the duration of the standby state is greater than the third preset duration, when the battery pack is powered on again, obtain the current voltage of the battery pack;

[0114] Step 017: Determine the remaining charge based on the current voltage. Wherein, in the standby state, there is a preset mapping relationship between the voltage and the remaining charge of the battery pack.

[0115] Wherein, the third preset duration can be the depolarization duration, etc.

[0116] Wherein, the standby state can be a state where the battery pack is in low power consumption (for example, the current value of the battery pack is less than the standby detection current, etc.). In the standby state, the battery pack is not charged or discharged, but there is a certain self-discharge process.

[0117] Specifically, when the battery pack is in the standby state (the battery pack is not charging or discharging), there is a preset mapping relationship (i.e., the OCV-SOC mapping relationship) between the open circuit voltage (OCV) of the battery pack and the remaining power of the battery pack. When the battery pack is in the standby state, due to the polarization effect, the open circuit voltage of the battery pack may be different from the open circuit voltage mapped by the actual remaining power of the battery pack at present. Therefore, when the battery pack is in the standby state and the duration of the standby state is greater than the third preset duration (the third preset duration can be the depolarization duration), it can be considered that the battery pack has recovered from the polarized state (the polarization phenomenon has been eliminated), that is, the current voltage (open circuit voltage) of the battery pack has become stable. When the battery pack is powered on again, the SOC of the battery pack can be determined based on the current voltage (open circuit voltage) of the battery pack through the OCV-SOC mapping relationship. Even after the battery pack has been on standby for a long time, its SOC can still be accurately evaluated, which is helpful for the health management of the battery pack and the user's control of the battery state.

[0118] Please refer to Figure 10 , in some embodiments, the calibration method further includes:

[0119] Step 018: Re-determine the power compensation coefficient every second preset duration.

[0120] Among them, the second preset duration can be a duration such as 1s, 2s, 3s, etc. The second preset duration can be the interval duration for the battery pack to collect the voltage of the battery cell.

[0121] Specifically, every second preset duration, the power compensation coefficient is re-determined to calibrate the SOC of the battery pack. Taking the second preset duration as 1s as an example, that is, every 1s, the corresponding power compensation coefficient is recalculated according to the first target voltage and the second target voltage of the previous second, so as to achieve the effect of real-time updating, adjusting and calibrating the SOC of the battery pack according to the voltage of the battery cell of the battery pack, and improving the calibration accuracy of the SOC.

[0122] Please refer to Figure 11 , to facilitate better implementation of the calibration method of the embodiments of the present application, the embodiments of the present application further provide a calibration device 300. The calibration device 300 is used for the battery pack. The calibration device 300 includes a first determination module 301 and a second determination module 302. The first determination module 301 is used to determine the power compensation coefficient based on the voltage change trend of the battery pack when the current voltage of the battery pack is within the preset power compensation range; the second determination module 302 is used to determine the remaining power based on the power compensation coefficient and the current power.

[0123] In some embodiments, the battery pack includes battery cells, and the first determination module 301 is further specifically configured to determine a power compensation coefficient based on the change trend of the voltage of the battery cells.

[0124] In some embodiments, there are multiple battery cells, and the first determination module 301 is further specifically configured to determine a first target voltage among the current voltages of the multiple battery cells and a second target voltage among the current voltages of the multiple battery cells before a first preset duration based on the charge and discharge conditions of the battery pack; determine the voltage change speed based on the first target voltage and the second target voltage; determine the charge and discharge end duration based on the voltage change speed and the cut-off voltage of the battery pack; and determine the power compensation coefficient based on the charge and discharge end duration and the current power.

[0125] In some embodiments, the preset power compensation range includes a first preset voltage threshold and a second preset voltage threshold, and the first preset voltage threshold is greater than the second preset voltage threshold. The calibration device 300 further includes a third determination module 303, and the third determination module 303 is configured to determine that the current voltage of the battery pack is within the preset power compensation range when the battery pack is in a charging condition and the current voltage of the battery pack is greater than the first preset voltage threshold; and determine that the current voltage of the battery pack is within the preset power compensation range when the battery pack is in a discharging condition and the current voltage of the battery pack is less than the second preset voltage threshold.

[0126] In some embodiments, the calibration device 300 further includes a fourth determination module 304, and the fourth determination module 304 is configured to re-determine the power compensation coefficient every second preset duration.

[0127] In some embodiments, the calibration device 300 further includes a fifth determination module 305, and the fifth determination module 305 is configured to, when the battery pack is in a standby state and the duration of the standby state is greater than a third preset duration, obtain the current voltage of the battery pack when the battery pack is powered on again; and determine the remaining power based on the current voltage, wherein there is a preset mapping relationship between the voltage and the remaining power of the battery pack in the standby state.

[0128] In some embodiments, the calibration device 300 further includes a display module 306, and the display module 306 is configured to update the currently displayed power of the battery pack based on the remaining power.

[0129] In some embodiments, the display module 306 is further specifically configured to display the current displayed power when the operating condition of the battery pack is a charging condition and the remaining power is less than the current displayed power; display the remaining power when the operating condition of the battery pack is a charging condition and the remaining power is greater than the current displayed power; display the current displayed power when the operating condition of the battery pack is a discharging condition and the remaining power is greater than the current displayed power; and display the remaining power when the operating condition of the battery pack is a discharging condition and the remaining power is less than the current displayed power.

[0130] Please refer again to Figure 1 , an energy storage device provided by an embodiment of the present application includes: a battery pack and a controller; and a computer program, wherein the computer program is stored in the controller and executed by the controller, and the computer program includes instructions for executing the calibration method of any of the above embodiments.

[0131] In some embodiments, the controller may include a microcontroller (MCU), or may include multiple discrete devices, such as a processor and a memory. The processor and / or the memory are used to store the computer program, and the processor is used to execute the computer program.

[0132] In some embodiments, the energy storage device may include an emergency start power supply, a portable energy storage power supply, an automotive battery, or a power tool, etc. Among them, the power tool may include an air pump, a car washer, an electric wrench, a blower, etc.

[0133] In some embodiments, the battery pack may include at least one of a sodium battery, a lithium battery, and a lead-acid battery. In other embodiments, the battery pack may further include other types of batteries, which are not limited in the present application.

[0134] In some embodiments, the energy storage device includes a battery pack. The battery pack 100 includes a processor, a memory; and a computer program, wherein the computer program is stored in the memory and executed by the processor, and the computer program includes instructions for executing the calibration method described in any of the above embodiments.

[0135] It can be understood that the energy storage device 1000 of the embodiment of the present application can achieve the same technical effects as the calibration method described in any of the above embodiments. To avoid repetition, it will not be elaborated here.

[0136] Please refer to Figure 12 , an embodiment of the present application further provides a computer-readable storage medium 600, on which a computer program 610 is stored. When the computer program 610 is executed by a processor 620, the steps of the calibration method of any of the above embodiments are implemented. For the sake of brevity, it will not be elaborated here.

[0137] In the description of this specification, the descriptions referring to terms such as "certain embodiments", "in one example", "exemplarily", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0138] Any process or method description shown in a flowchart or described in other ways herein can be understood as representing a module, segment or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0139] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A calibration method, characterized in that, For a battery pack, the method includes: When the current voltage of the battery pack is within a preset power compensation range, determining a power compensation coefficient based on the voltage change trend of the battery pack; Determining the remaining power based on the power compensation coefficient and the current power.

2. The calibration method according to claim 1, wherein The battery pack includes battery cells. The determining the power compensation coefficient based on the voltage change trend of the battery pack includes: Determining a power compensation coefficient based on the voltage change trend of the battery cells.

3. The calibration method according to claim 2, wherein There are multiple battery cells. The determining the power compensation coefficient based on the voltage change trend of the battery cells includes: Based on the charge and discharge conditions of the battery pack, determining a first target voltage among the current voltages of the multiple battery cells and a second target voltage among the current voltages of the multiple battery cells before a first preset duration; Determining the voltage change speed based on the first target voltage and the second target voltage; Determining the charge and discharge end duration based on the voltage change speed and the cut-off voltage of the battery pack; Determining the power compensation coefficient based on the charge and discharge end duration and the current power.

4. The calibration method according to claim 3, characterized in that The charge and discharge conditions of the battery pack include a charging condition, and the cut-off voltage includes a charging cut-off voltage. When the charge and discharge condition of the battery pack is the charging condition, the cut-off voltage is the charging cut-off voltage, and the end duration T is determined based on the following formula: T = (Vcp - V1) / (V1 - V2) Where, Vcp is the charging cut-off voltage, V1 is the first target voltage, and V2 is the second target voltage.

5. The calibration method according to claim 4, wherein The power compensation coefficient Qd is determined based on the following formula: Qd = (Qr - Qn) / T Where, Qr is the rated capacity of the battery pack, Qn is the current capacity of the battery pack, and T is the end duration.

6. The calibration method according to claim 5, characterized in that The determining the remaining power SOC based on the power compensation coefficient and the current power is determined based on the following formula: SOC = ((Qn + Qd) / Qr) * 100% Where, Qn is the current capacity of the battery pack, Qd is the power compensation coefficient, and Qr is the rated capacity of the battery pack.

7. The calibration method according to any one of claims 4-6, characterized in that, The first target voltage includes the maximum voltage among the current voltages of the multiple battery cells, or the first target voltage includes the average value of the current voltages of the multiple battery cells; the second target voltage includes the maximum voltage among the current voltages of the multiple battery cells before a first preset duration, or the second target voltage includes the average value of the current voltages of the multiple battery cells before a first preset duration.

8. The calibration method according to claim 3, wherein The charge and discharge conditions include a discharging condition, and the cut-off voltage includes a discharging cut-off voltage. When the condition of the battery pack is the discharging condition, the cut-off voltage is the discharging cut-off voltage, and the end duration T is determined based on the following formula: T = (V1 - Vdp) / (V2 - V1) Where, Vdp is the discharging cut-off voltage, V1 is the first target voltage, and V2 is the second target voltage.

9. The calibration method according to claim 8, wherein The power compensation coefficient Qd is determined based on the following formula: Qd = Qn / T Wherein, Qn is the current capacity of the battery pack, and T is the end duration.

10. The calibration method according to claim 9, wherein, Based on the power compensation coefficient and the current power, the remaining power SOC is determined based on the following formula: SOC = ((Qn - Qd) / Qr) * 100% Wherein, Qn is the current capacity of the battery pack, Qd is the power compensation coefficient, and Qr is the rated capacity of the battery pack.

11. The calibration method according to any one of claims 8-10, characterized in that, The first target voltage includes the minimum voltage among the current voltages of multiple battery cells, or the first target voltage includes the average value of the current voltages of multiple battery cells; the second target voltage includes the minimum voltage among the current voltages of multiple battery cells before a first preset duration, or the second target voltage includes the average value of the current voltages of multiple battery cells before a first preset duration.

12. The calibration method according to claim 1, wherein The preset power compensation range includes a first preset voltage threshold and a second preset voltage threshold, and the first preset voltage threshold is greater than the second preset voltage threshold. The method further includes: When the battery pack is in a charging condition and the current voltage of the battery pack is greater than the first preset voltage threshold, it is determined that the current voltage of the battery pack is within the preset power compensation range; When the battery pack is in a discharging condition and the current voltage of the battery pack is less than the second preset voltage threshold, it is determined that the current voltage of the battery pack is within the preset power compensation range.

13. The calibration method according to claim 1, wherein The method further includes: Re-determining the power compensation coefficient every second preset duration.

14. The calibration method according to claim 1, characterized in that The method further includes: When the battery pack is in a standby state and the duration of the standby state is greater than a third preset duration, when the battery pack is powered on again, obtain the current voltage of the battery pack; Determine the remaining power based on the current voltage, wherein in the standby state, there is a preset mapping relationship between the voltage and the remaining power of the battery pack.

15. The calibration method according to any one of claims 1 and 14, characterized in that The method further includes: Update the currently displayed power of the battery pack based on the remaining power.

16. The calibration method according to claim 15, wherein The updating the currently displayed power of the battery pack based on the remaining power includes: When the working condition of the battery pack is a charging condition and the remaining power is less than the currently displayed power, then display the currently displayed power; When the working condition of the battery pack is a charging condition and the remaining power is greater than the currently displayed power, then display the remaining power; When the working condition of the battery pack is a discharging condition and the remaining power is greater than the currently displayed power, then display the currently displayed power; When the working condition of the battery pack is a discharging condition and the remaining power is less than the currently displayed power, then display the remaining power.

17. An energy storage device, characterized in that, Including: A battery pack and a controller; And A computer program, wherein the computer program is stored in the controller and executed by the controller, and the computer program includes instructions for executing the calibration method according to any one of claims 1 to 16.

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