Remaining electric quantity determination method and energy storage equipment

Abstract

The invention relates to the technical field of energy storage, in particular to a remaining power determination method and energy storage equipment. The method comprises the following steps: acquiring charging and discharging parameters of each single battery cell in a battery pack; when the charging and discharging parameters meet a correction triggering condition, acquiring a current capacity retention ratio of the battery pack; according to the capacity retention ratio and the charging and discharging parameters, determining the minimum residual electric quantity of a single battery of the battery pack; determining the target residual electric quantity of the battery pack according to the minimum residual electric quantity of the single battery and the capacity retention ratio; and determining the display residual electric quantity according to the target residual electric quantity. The method can improve the determination accuracy of the residual electric quantity of the energy storage system.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a method for determining remaining power and an energy storage device. Background Art

[0002] In daily use, the battery pack's remaining capacity (State of Charge, SOC) is difficult to accurately calculate due to factors such as the battery pack's internal resistance, remaining capacity, aging, and wiring resistance. In particular, when the battery pack is nearing full charge or empty, there can be a significant deviation between the actual remaining capacity and the calculated value. Summary of the Invention

[0003] In view of this, embodiments of the present application provide a method for determining the remaining power and an energy storage device, which can effectively improve the accuracy of determining the remaining power of an energy storage system.

[0004] In a first aspect, an embodiment of the present application provides a method for determining remaining power, including:

[0005] Obtain the charge and discharge parameters of each single cell in the battery pack;

[0006] When the charge and discharge parameters meet the correction trigger condition, obtaining the current capacity retention rate of the battery pack;

[0007] Determining the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the charge and discharge parameters;

[0008] Determining a target remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate;

[0009] The displayed remaining power at the current moment is determined according to the target remaining power.

[0010] In some embodiments, based on the above embodiments, the acquiring of the charge and discharge parameters of each single cell in the battery pack includes current parameters and temperature parameters of the single cell;

[0011] When the charge and discharge parameters meet the correction trigger condition, obtaining the current capacity retention rate of the battery pack includes:

[0012] The capacity retention rate is determined according to the current parameters and temperature parameters of the single battery cell.

[0013] In some embodiments, based on the above embodiments, the acquiring of the charge and discharge parameters of each single cell in the battery pack includes current parameters and voltage parameters of the single cell;

[0014] The method further comprises:

[0015] When the battery pack is in a discharging state, if there is a single cell whose voltage parameter is within a preset correction voltage range, confirming that the charge and discharge parameters meet the correction trigger condition; and / or,

[0016] When the battery pack is in a charging state, if the current parameter of a single cell is within a preset correction current range, it is confirmed that the charge and discharge parameters meet the correction trigger condition.

[0017] In some embodiments, based on the above embodiments, determining the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the charge and discharge parameters includes:

[0018] When the battery pack is in a discharging state, determining the minimum remaining power of the battery pack cells according to the minimum voltage of the battery pack cells, the discharge correction parameter threshold, and the capacity retention rate; and / or,

[0019] When the battery pack is in a charging state, the remaining capacity difference of each single cell in the battery pack is obtained, and the minimum remaining capacity of the single cell of the battery pack is determined according to the remaining capacity difference, the capacity retention rate, the charging correction parameter threshold and the current parameter.

[0020] In some embodiments, based on the above embodiments, the discharge correction parameter thresholds include a discharge start correction remaining capacity, a discharge exit correction remaining capacity, a discharge start correction voltage value, and a discharge exit correction voltage value; and / or,

[0021] The charging correction parameter thresholds include a charging start correction remaining capacity, a charging exit correction remaining capacity, a charging start correction current value, and a charging exit correction current value.

[0022] In some embodiments, based on the above embodiments, determining the target remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate includes:

[0023] Calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell;

[0024] Calculating the actual maximum capacity of the battery pack according to the capacity retention rate;

[0025] The target remaining power is obtained according to a ratio of the available remaining power to the actual maximum capacity.

[0026] In some embodiments, based on the above embodiments, calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell includes:

[0027] When the battery pack is in a discharging state, calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate; and / or,

[0028] When the battery pack is in a charging state, the minimum remaining power of the single cell is used as the current available remaining power of the battery pack.

[0029] In some embodiments, based on the above embodiment, calculating the current actual maximum capacity of the battery pack according to the capacity retention rate includes:

[0030] Obtaining the remaining capacity difference of each single cell in the battery pack;

[0031] The current actual maximum capacity of the battery pack is calculated according to the remaining capacity difference and the capacity retention rate.

[0032] In some embodiments, based on the above embodiment, determining the displayed remaining power at the current moment according to the target remaining power includes:

[0033] Calculating the difference between the displayed remaining power of the battery pack at the last moment and the target remaining power;

[0034] Calculating a voltage difference between a voltage parameter of a single cell of the battery pack and a target voltage parameter;

[0035] determining a display correction coefficient according to a ratio between the remaining power difference and the voltage difference;

[0036] The displayed remaining power at the current moment is determined according to the display correction coefficient and the accumulated charge and discharge power.

[0037] In a second aspect, an embodiment of the present application provides an energy storage device, which includes a processor and a memory, and the processor is used to implement the above-mentioned remaining power determination method when executing a computer program stored in the memory.

[0038] The embodiments of the present application have the following beneficial effects:

[0039] The present application provides a method for determining remaining power, including: obtaining the charge and discharge parameters of each single cell in a battery pack; obtaining the current capacity retention rate of the battery pack when the charge and discharge parameters meet a correction trigger condition; determining the minimum remaining power of each cell in the battery pack based on the capacity retention rate and the charge and discharge parameters; determining the target remaining power of the battery pack based on the minimum remaining power of each cell and the capacity retention rate; and determining the displayed remaining power at the current moment based on the target remaining power. The present application can effectively improve the accuracy of determining the remaining power of an energy storage system through three-level corrections: the minimum remaining power of each cell, the target remaining power, and the displayed remaining power. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. 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 relevant drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A diagram showing an application scenario of the method for determining the remaining power provided in one embodiment of the present application is shown;

[0042] Figure 2 A schematic diagram showing a flow chart of a method for determining remaining power according to one embodiment of the present application is shown;

[0043] Figure 3 A table showing the relationship between capacity retention, temperature, and current mapping proposed in one embodiment of the present application is shown;

[0044] Figure 4 A schematic diagram of a voltage-time discharge curve in one embodiment of the present application is shown;

[0045] Figure 5 A schematic diagram showing a flow chart of a method for determining remaining power according to one embodiment of the present application is shown;

[0046] Figure 6 A schematic diagram showing a flow chart of a method for determining remaining power according to one embodiment of the present application is shown;

[0047] Figure 7 A schematic diagram showing a flow chart of a method for determining remaining power according to one embodiment of the present application is shown;

[0048] Figure 8 A flow chart of a method for determining remaining power proposed in one embodiment of the present application is shown.

[0049] Explanation of main component symbols: 10-energy storage device; 11-battery pack; 12-controller; 13-memory. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0051] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0052] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0053] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0054] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0055] The current battery pack 11 has a wide range of application scenarios, and the battery pack 11 can be used in various types of equipment. For example, the battery pack 11 can be used in self-moving equipment such as automotive equipment, lawn mowing equipment, sweeping equipment, and cruise equipment. It can also be used in energy storage equipment such as mobile energy storage equipment 10 and household energy storage equipment 10, or it can also be used in electrical equipment such as refrigerators, air conditioners, washing machines, or other electronic devices that require the battery pack 11, without limitation. Accurately calculating the remaining power of the battery pack 11 can ensure that the user obtains more reliable power information, avoids the inability to meet the user's actual use needs due to insufficient power, and can also avoid overcharging or over-discharging of the battery pack 11, prevent damage or rapid aging of the battery pack 11, and thus extend its service life. In the present application, the battery pack 11 includes at least one battery cell. When the battery pack 11 includes multiple battery cells, the multiple battery cells can be connected in parallel, in series, or in series and parallel to form the battery pack 11.

[0056] However, during the battery pack 11's use, it is affected by numerous factors, including temperature, output power, aging, and self-discharge, which are difficult to estimate. This makes it difficult to accurately calculate the remaining capacity of the battery pack 11. In particular, when the battery pack 11 is nearing full charge (i.e., the end of charge) or empty (i.e., the end of discharge), cell parameters can become unstable, resulting in a significant deviation between the actual remaining capacity of the battery pack 11 and the currently displayed remaining capacity.

[0057] Therefore, in order to solve the above problems, an embodiment of the present application provides a method for determining the remaining power, which can improve the accuracy of determining the remaining power of the battery pack 11.

[0058] Figure 1 FIG1 shows an application scenario diagram of a remaining power determination provided by an embodiment of the present application. Figure 1 As shown, the energy storage device 10 includes a battery pack 11 , a controller 12 and a memory 13 .

[0059] Those skilled in the art should understand that Figure 1 The structure of the energy storage device 10 shown does not constitute a limitation of the embodiments of the present application. The energy storage device 10 may also include more or less other hardware or software than shown in the figure, or a different arrangement of components. For example, the energy storage device 10 may also include multiple interfaces, wherein the first interface is used to connect to a load to supply power to the load; the second interface is used to connect to an independent battery pack 11 to expand the capacity of the energy storage device 10; the third interface is used to connect to an AC power source to use the AC power source to charge the battery pack in the energy storage device 10 or to supply power to the load connected to the energy storage device 10; the fourth interface is used to connect to modules with other functions, such as solar panels, diesel engines, etc., so that solar energy and diesel engines can be used to power the energy storage device 10 itself or the load connected to the energy storage device 10.

[0060] In one embodiment of the present application, the energy storage device 10 may be an electronic device with energy storage functionality, including self-moving devices such as automotive devices, lawn mowers, sweepers, and cruise devices, as well as mobile energy storage devices 10, household energy storage devices 10, and other energy storage devices 10. Alternatively, the energy storage device 10 may be used in electrical appliances such as refrigerators, air conditioners, and washing machines, or other electronic devices including a battery pack 11. The energy storage device 10 may also include a client device, including but not limited to any electronic product capable of human-computer interaction with a client via a keyboard, mouse, remote control, touchpad, or voice-controlled device, such as a personal computer, tablet computer, smartphone, digital camera, and the like.

[0061] It should be noted that the energy storage device 10 is only an example. Other existing or future electronic products that are suitable for this application should also be included in the scope of protection of this application and incorporated herein by reference.

[0062] In some embodiments, the energy storage device 10 may also include a battery pack 11 that powers various components. The battery pack 11 may be connected to at least one control logic via a power management device (not shown), thereby enabling the power management device to implement functions such as charge and discharge management, as well as power consumption management. The energy storage device 10 may also include a power conversion module. The power conversion module may include at least one of a DC-DC conversion module and a DC-AC conversion module, thereby converting the DC power of the battery pack 11 in the energy storage device 10 into DC power or AC power, which is then output to power the corresponding load. It is understood that the power conversion module may also convert externally input DC power or AC power into the corresponding DC power and then charge the battery pack 11. When the energy storage device 10 has a bypass operating mode, it can also directly use the incoming AC power to power the load. When the AC power supply stops, the power supply is switched to the battery pack 11 to ensure that the load can operate without power loss. The energy storage device 10 may also include a wireless communication module. The wireless communication module may include at least one of a Bluetooth module and a WiFi module.

[0063] Figure 2 is a flow chart of a method for determining remaining power provided by an embodiment of the present application, the method for determining remaining power being applied to an energy storage device 10 (eg, Figure 1 Energy storage device 10). Figure 2 As shown, the method for determining the remaining power may include the following steps. According to different requirements, the order of the steps in the flowchart can be changed, and some steps can be omitted.

[0064] Step S110 : Obtain the charge and discharge parameters of each single cell in the battery pack 11 .

[0065] In some embodiments, the battery pack 11 includes a plurality of single cells, which may be connected in series or in parallel, without limitation. During use, each single cell may be in a charging state or a discharging state. The charge and discharge parameters refer to various parameters of the single cell in the charging or discharging state, which may be current, voltage, temperature, power, etc., without limitation.

[0066] It should be noted that when a single cell is in a charging state, its charge and discharge parameters include charging current, charging voltage, charging power, and charging temperature. When a single cell is in a discharging state, its charge and discharge parameters include discharge current, discharge voltage, discharge power, and discharge temperature, which are not limited here.

[0067] Step S210: When the charge and discharge parameters meet the correction trigger condition, the current capacity retention rate of the battery pack 11 is obtained.

[0068] In some embodiments, when the battery cells are at different temperatures or output powers, the actual capacity that can be used based on the current temperature or power limit is not the same. That is, considering that the actual available capacity of the single cell is different under different currents and different temperatures, therefore, in the process of correcting the remaining power of the battery pack 11, it is necessary to obtain the current capacity retention rate of the battery pack 11 to ensure that the remaining power finally calculated matches the actual available capacity. Among them, the capacity retention rate refers to the remaining power SOC that the battery cell can actually release under given current and temperature conditions. Therefore, based on the above embodiment, the charge and discharge parameters of each single cell in the battery pack 11 are obtained, including the current parameters and temperature parameters of the single cell. When the charge and discharge parameters meet the correction trigger conditions, the capacity retention rate can be determined based on the current parameters and temperature parameters of the single cell.

[0069] In some embodiments, the material, process, environmental conditions and structure of the battery cell will affect the capacity retention rate. Therefore, several battery cells from the same batch (i.e., the process, material and structure conditions can be considered the same) can be tested in advance to obtain a capacity retention rate table for the battery cells in the batch at different temperatures and currents. Figure 3 The capacity retention rate table of a type of battery pack 11 is shown. Optionally, the temperature is the temperature of the battery pack 11 when discharge is terminated. In one embodiment, the capacity retention rate table can be pre-stored in a memory so that it can be directly called when needed.

[0070] Alternatively, based on the current current and temperature parameters of the battery cell, the capacity retention rate table corresponding to the disclosed battery cell is queried. Since the capacity of the battery cells in the battery pack remains unchanged when connected in series, the capacity retention rate of the single battery cell can also be used as the capacity retention of the battery pack 11, and the obtained capacity retention rate of the battery cell is used as the current capacity retention rate of the battery pack 11.

[0071] During the use of the battery pack, inconsistent cell temperatures often occur. In this embodiment, the lowest cell temperature is used to determine the capacity retention rate, so the lowest cell temperature has the greatest restriction on capacity release.

[0072] In this embodiment, whether to trigger the correction of the remaining power level is determined by different triggering conditions in the charging state and the discharging state. Therefore, when determining whether to trigger the correction of the remaining power level, it is necessary to determine the corresponding correction triggering condition based on the current state of the battery pack and then determine whether the correction triggering condition is met.

[0073] In some embodiments, the battery pack 11 is charged at a constant voltage. Thus, when the battery pack 11 is at the end of charging, its voltage remains essentially unchanged, while its current gradually decreases, with the current change being more pronounced. Therefore, the charging current is used to determine whether the correction trigger condition has been met. However, during the discharge process, the voltage change of the battery pack 11 is more pronounced than the current change. Therefore, the discharge current is used to determine whether the correction trigger condition has been met. The correction trigger condition can be determined through experience or testing. Typically, when the corresponding parameters of the battery pack meet the correction trigger condition, it is considered necessary to correct the remaining charge, and subsequent correction steps are executed.

[0074] Therefore, in some embodiments, obtaining the charge and discharge parameters of each single cell in the battery pack 11 includes the current parameter and voltage parameter of the single cell; and determining whether the charge and discharge parameters meet the correction trigger condition may include the following situations:

[0075] First, when the battery pack 11 is in a discharging state, if the voltage parameter of a single cell is within a preset correction voltage range, it is confirmed that the charge and discharge parameters meet the correction trigger condition.

[0076] Second, when the battery pack 11 is in a charging state, if the current parameter of a single cell is within the preset correction current range, it is confirmed that the charge and discharge parameters meet the correction trigger condition.

[0077] The preset correction voltage range refers to the voltage range within which the remaining power needs to be corrected when the voltage parameters of a single cell are within this voltage range. The preset correction voltage range can be pre-stored in a memory. This preset correction voltage range can be obtained through multiple sampling tests or configured at the factory. The preset correction voltage range can vary depending on the discharge power. The preset correction voltage range includes a discharge start correction voltage value and a discharge exit correction voltage value. In one embodiment, the preset correction voltage range can be determined based on the mapping relationship between the discharge rate of the cell at the end of discharge and the cell voltage.

[0078] The preset correction current range refers to the current range within which the remaining charge of a single cell needs to be corrected. The preset correction current range includes the charge start correction current value and the charge exit correction current value. During constant voltage charging, as the cell approaches full charge, the current gradually decreases. Therefore, a current value can be determined based on the corresponding remaining charge as the charge start correction current value. The charge exit correction current value can be determined by adding a certain margin (for example, 1A) to the current when the cell is fully charged.

[0079] Therefore, regardless of the charging state or the discharging state, when the corresponding parameters meet the corresponding correction range, it can be confirmed that the current charging and discharging parameters meet the correction trigger conditions, thereby performing terminal correction on the remaining power.

[0080] Step S310: Determine the minimum remaining capacity of each cell of the battery pack 11 according to the capacity retention rate and the charge and discharge parameters.

[0081] In some embodiments, there are differences in the remaining power of each single cell in the battery pack 11. In order to ensure that the calculated remaining power matches the remaining power that the battery pack 11 can actually output, this embodiment selects the minimum remaining power among the remaining power of all single cells as the basis for calculation. In this embodiment, when the correction trigger condition is not met, there is no need to correct the remaining power. At this time, the minimum remaining power can be updated by the ampere-hour integration method. When the correction trigger condition is met, the terminal correction (which can be a charging terminal correction or a discharging terminal correction) will be triggered. At this time, it is necessary to determine the minimum remaining power based on the terminal state, that is, to determine the minimum remaining power of the single cell of the battery pack 11 based on the capacity retention rate and the charge and discharge parameters.

[0082] Step S410: Determine the target remaining power of the battery pack 11 according to the minimum remaining power of the cell and the capacity retention rate.

[0083] Because the minimum remaining battery capacity of a single cell reflects the lowest state of the cell and does not take into account actual usage and environmental changes, after determining the minimum remaining battery capacity of a single cell, it is necessary to consider other factors that affect the remaining capacity to determine the final target remaining capacity, so that the calculated target remaining capacity is more timely and accurate.

[0084] In this embodiment, considering that there are multiple factors (such as capacity retention rate, etc.) that affect the target remaining power during the charging and discharging process, in order to make the determined target remaining power more accurate, the capacity retention rate is added when determining the target remaining power.

[0085] Step S510: Determine the current displayed remaining power according to the target remaining power. In some embodiments, Figure 4 The following diagram shows the discharge characteristics of a single battery cell, with time t plotted on the horizontal axis and voltage v (unit: millivolts) plotted on the vertical axis. Clearly, the voltage-time curve is not a linear process. Before the end of discharge, the voltage change of a single cell is approximately stable. However, near the end of discharge, the voltage of a single cell changes significantly, which can easily cause a dramatic change in the remaining charge and fail to accurately reflect the battery's true state. Therefore, the remaining charge at the end of discharge must be corrected to ensure that it reflects the battery's true state during the charge and discharge process, especially when approaching the charge and discharge limits.

[0086] After determining the target remaining battery life, to avoid drastic jumps in the SOC displayed to the user that could degrade the user experience, the display correction rate is determined based on the deviation between the previous remaining battery life and the target remaining battery life, thereby determining the current remaining battery life. The greater the deviation between the previous remaining battery life and the target remaining battery life, the faster the display correction rate, and vice versa.

[0087] In another embodiment, when updating the remaining power display, the proximity between the current cell voltage and the voltage in the fully charged or terminated discharge state is also considered. The closer the voltage is, the faster the display correction speed is, and vice versa.

[0088] The above-mentioned remaining power determination method obtains the charge and discharge parameters of each single cell in the battery pack; when the charge and discharge parameters meet the correction trigger condition, obtains the current capacity retention rate of the battery pack; determines the minimum remaining power of each cell in the battery pack based on the capacity retention rate and the charge and discharge parameters; determines the target remaining power of the battery pack based on the minimum remaining power of each cell and the capacity retention rate; and determines the displayed remaining power at the current moment based on the target remaining power. The embodiments of the present application can effectively improve the accuracy of the remaining power determination of the energy storage system by performing three-level corrections for the minimum remaining power of each cell, the target remaining power, and the displayed remaining power.

[0089] In one embodiment, step S310 determines the minimum remaining capacity of a single cell of the battery pack 11 based on the capacity retention rate and the charge and discharge parameters. This includes determining the minimum remaining capacity of a single cell of the battery pack based on the minimum voltage of the single cell of the battery pack, the discharge correction parameter threshold, and the capacity retention rate when the battery pack is in a discharging state. The discharge correction parameter threshold is a parameter threshold for entering or exiting discharge correction.

[0090] Specifically, the discharge correction parameter thresholds may include the discharge start correction remaining capacity, the discharge exit correction remaining capacity, the discharge start correction voltage value, and the discharge exit correction voltage value. The discharge start correction remaining capacity refers to the remaining capacity when the remaining capacity correction is started in the discharge state, that is, the remaining capacity from the inflection point of the remaining capacity-cell voltage curve to the emptying during the discharge process, such as 7%. The discharge exit correction remaining capacity refers to the remaining capacity when the remaining capacity correction is exited in the discharge state. The discharge start correction voltage value refers to the cell voltage when the remaining capacity correction is started in the discharge state. The discharge exit correction voltage value refers to the cell voltage when the remaining capacity correction is exited in the discharge state. Usually, the discharge start correction voltage value matches the voltage value corresponding to the discharge start correction remaining capacity, and the discharge exit correction voltage value matches the voltage value corresponding to the discharge exit correction remaining capacity.

[0091] In another embodiment, step S310 determines the minimum remaining power of the single cells of the battery pack 11 based on the capacity retention rate and the charge and discharge parameters, including: when the battery pack is in a charging state, obtaining the remaining capacity difference of each single cell in the battery pack, and determining the minimum remaining power of the single cells of the battery pack based on the remaining capacity difference, the capacity retention rate, the charging correction parameter threshold and the current parameter.

[0092] Among them, the charging correction parameter threshold is the parameter threshold when entering or exiting the charging correction. Specifically, the charging correction parameter threshold may include the charging start correction remaining power, the charging exit correction remaining power, the charging start correction current value, and the charging exit correction current value. The charging start correction remaining power refers to the remaining power when the remaining power correction starts in the charging state. The charging exit correction remaining power refers to the remaining power when the remaining power correction is exited in the charging state. The charging start correction current value refers to the charging current when the remaining power correction starts in the charging state. The charging exit correction current value refers to the charging current when the remaining power correction is exited in the charging state. Generally, the charging start correction current value matches the current value corresponding to the charging start correction remaining power, and the charging exit correction current matches the current corresponding to the charging exit correction remaining power.

[0093] In some embodiments, as Figure 5 As shown, when the battery pack 11 is in a discharging state, the minimum remaining capacity of the battery pack 11 is determined according to the minimum voltage of the battery pack 11, the discharge correction parameter threshold, and the capacity retention rate, including:

[0094] Step S311 : determining the theoretical minimum remaining capacity according to the discharge correction parameter threshold and the cell minimum voltage.

[0095] As mentioned above, the discharge correction parameter thresholds include the discharge start correction remaining capacity, discharge exit correction remaining capacity, discharge start correction voltage value, and discharge exit correction voltage value. At the end of discharge, there is a certain linear relationship between the remaining capacity and the single cell voltage. Therefore, the theoretical minimum remaining capacity MinSoc can be determined based on the discharge correction parameter thresholds and the single cell minimum voltage. 0d .

[0096] Specifically, the theoretical minimum remaining capacity MinSoc is determined based on the discharge correction parameter threshold and the cell minimum voltage. 0d The formula is as follows:

[0097]

[0098] Among them, EnterSoc1 is the corrected remaining capacity at the start of discharge, ExitSoc1 is the corrected remaining capacity at the end of discharge, EnterVolt1 is the corrected voltage value at the start of discharge, ExitVolt1 is the corrected voltage value at the end of discharge, and MinVolt is the minimum voltage of the single cell.

[0099] Step S312: Determine the actual minimum available remaining power as the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the theoretical minimum remaining power.

[0100] As mentioned above, the actual usable capacity of a battery cell varies due to different temperatures and output power levels. Therefore, when calculating the minimum remaining capacity of a single cell, we use the capacity retention rate to correct it, ensuring that the calculated minimum remaining capacity of the cell is closest to the actual minimum remaining capacity.

[0101] Specifically, the formula for calculating the minimum remaining power of a single cell is as follows:

[0102]

[0103] Among them, MinSoc1 is the final minimum remaining capacity of the single cell, and RetenSoc is the capacity retention rate at the current moment. Therefore, (1-RetenSoc) is the capacity of the single cell that cannot be discharged due to various conditions (such as low external temperature, output power limit, etc.). It should be noted that this part of the capacity can be released when the single cell reaches the appropriate conditions. By adding the calculated theoretical minimum remaining capacity to the energy that cannot actually be discharged under the current conditions, the minimum remaining capacity of the single cell is obtained.

[0104] Optionally, the value of the discharge start correction remaining power can be 7%, and the value of the discharge exit correction remaining power can be 1%. Of course, there is no limitation here, and the discharge start correction remaining power / discharge exit correction remaining power can also be other values.

[0105] Alternatively, the discharge start correction voltage value may be a discharge voltage value corresponding to an inflection point in the voltage-time curve of the discharge of the above-mentioned single cell.

[0106] Optionally, the discharge exit correction voltage value may be a discharge voltage value corresponding to the discharge exit correction remaining power.

[0107] In some embodiments, as Figure 6 As shown, when the battery pack 11 is in a charging state, the remaining capacity difference of each single cell in the battery pack 11 is obtained, and the minimum remaining capacity of the single cell of the battery pack 11 is determined according to the remaining capacity difference, the capacity retention rate, the charging correction parameter threshold and the current parameter, including:

[0108] Step S321, determine the theoretical maximum remaining capacity based on the charge correction parameter threshold and the current parameter. As mentioned above, the charge correction parameter threshold includes the charge start correction remaining capacity, the charge exit correction remaining capacity, the charge start correction current value, and the charge exit correction current value. At the end of charging, since the charging process is constant voltage charging, the voltage remains unchanged, and there is a certain linear relationship between the remaining capacity and the current parameter, so the theoretical maximum remaining capacity MaxSoc can be determined based on the charge correction parameter threshold and the current parameter. 0c .

[0109] Specifically, the theoretical maximum remaining capacity MaxSoc is determined based on the charging correction parameter threshold and the current parameter. 0c The formula is as follows:

[0110]

[0111] Among them, EnterSoc2 is the remaining power corrected at the start of charging, ExitSoc2 is the remaining power corrected at the end of charging, EnterCur is the current value corrected at the start of charging, ExitCur is the current value corrected at the end of charging, and I is the current parameter.

[0112] Step S322: Determine the actual minimum available remaining power as the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the theoretical maximum remaining power.

[0113] As mentioned above, the actual usable capacity of a battery cell varies due to different temperatures and output power levels. Therefore, when calculating the minimum remaining capacity of a single cell, we use the capacity retention rate to correct it, ensuring that the calculated minimum remaining capacity of the cell is closest to the actual minimum remaining capacity.

[0114] Specifically, the formula for calculating the minimum remaining power of a single cell is as follows:

[0115] MinSoc2=(1-RetenSoc-DiffSoc)+MaxSoc 0c ;

[0116] Right now,

[0117] Among them, MinSoc2 is the final minimum remaining capacity of the single cell, and RetenSoc is the capacity retention rate at the current moment. Therefore, (1-RetenSoc) is the capacity of the single cell that cannot be discharged due to various conditions (such as low external temperature, output power limit, etc.). It should be noted that this part of the capacity can be released when the single cell reaches the appropriate conditions. By adding the calculated theoretical maximum remaining capacity to the energy that cannot be discharged under the current conditions, the maximum remaining capacity of the single cell is obtained, that is, Then subtract the difference between the largest cell remaining power and the smallest cell remaining power (i.e. the remaining capacity difference, which can be tested and stored in advance and can be directly called when used) to obtain the smallest cell remaining power.

[0118] Optionally, the value of the charge start correction remaining power can be 95%, and the value of the charge exit correction remaining power can be 99%. Of course, there is no limitation here, and the charge start correction remaining power / charge exit correction remaining power can also be other values.

[0119] Optionally, the charge start correction current value may be a charge current value corresponding to the charge start correction remaining capacity.

[0120] Optionally, the charge exit correction voltage value may be the full charge current value of the current model of the single cell or the full charge current value plus a certain margin (such as 1A).

[0121] In some embodiments, as Figure 7 Step S410, determining the target remaining power of the battery pack 11 according to the minimum remaining power of the single cell and the capacity retention rate, includes:

[0122] Step S411 : Calculate the current available remaining power of the battery pack 11 according to the minimum remaining power of each cell.

[0123] In some embodiments, when the battery pack 11 is in a discharging state, the current available remaining capacity of the battery pack 11 can be calculated based on the minimum remaining capacity of the single cell and the capacity retention rate. Since the minimum remaining capacity of the single cell includes the capacity that cannot be released due to limitations such as temperature and output power, this portion needs to be subtracted from the actual available remaining capacity during the discharging state. In other words, the current available remaining capacity of the battery pack 11 can be the difference between the minimum remaining capacity of the single cell and the capacity that cannot be released due to parameter limitations, which can be expressed as:

[0124] MinSoc A =MinSoc1-(1-RetenSoc);

[0125] Among them, MinSoc A The current available remaining charge in the battery pack. MinSoc1 is the calculated minimum remaining charge in a single cell, and RetenSoc is the calculated capacity retention rate. (1-RetenSoc) represents the capacity of a single cell that cannot be released due to various conditions (such as low ambient temperature). This capacity can be released when the cell meets the appropriate conditions.

[0126] In some embodiments, when the battery pack 11 is in a charging state, the portion of the capacity that cannot be released due to temperature and power restrictions does not affect the charging process of the battery pack 11. Therefore, the current minimum remaining capacity of the battery pack 11 can be used as the current available remaining capacity of the battery pack 11, that is, MinSoc A =MinSoc2.

[0127] Step S412: Calculate the current actual maximum capacity of the battery pack 11 according to the capacity retention rate.

[0128] In some embodiments, to calculate the current actual maximum capacity of the battery pack 11, it is necessary to first obtain the remaining capacity difference of each single cell in the battery pack 11, and then calculate the current actual maximum capacity of the battery pack 11 based on the remaining capacity difference and the capacity retention rate.

[0129] The remaining capacity difference refers to the difference between the maximum and minimum remaining capacity of a cell in the battery pack 11. The remaining capacity difference has a certain degree of stability during the use of the battery pack. Therefore, the remaining capacity of each cell can be measured after the cells in the battery pack are left to rest, and the maximum and minimum remaining capacity of the cells can be determined, and the remaining capacity difference between the two can be calculated. The remaining capacity difference obtained can be directly called in subsequent calculations. It is understood that in one embodiment, the remaining capacity difference can also be measured regularly to ensure that the remaining capacity finally calculated has a high degree of accuracy.

[0130] Since the actual maximum capacity of the battery pack does not change due to the current charging or discharging state, it mainly depends on the restrictions of temperature, power and other conditions on the actual releasable capacity, as well as the influence of the remaining capacity difference. Therefore, the actual maximum capacity of the battery pack, MinSoc, can be determined based on the capacity retention rate and the remaining capacity difference. B :

[0131] MinSoc B =1-DiffSoc-(1-RetenSoc).

[0132] Among them, DiffSoc is the remaining capacity difference, and (1-RetenSoc) is the capacity of the single cell that cannot be released due to various conditions (such as the external temperature is too low).

[0133] Step S413: Obtain the target remaining power according to the ratio of the available remaining power to the actual maximum capacity.

[0134] In some embodiments, when the battery pack 11 is in a discharging state, the target remaining power may be calculated as follows:

[0135]

[0136] TargetSoc1 is the target remaining capacity calculated in the discharge state.

[0137] In some embodiments, when the battery pack 11 is in a charging state, the target remaining power may be calculated as follows:

[0138]

[0139] TargetSoc2 is the target remaining power calculated under charging status.

[0140] In some embodiments, based on the above embodiments, Figure 8 As shown, determining the current displayed remaining power according to the target remaining power includes:

[0141] Step S511 : Calculate the remaining power difference between the last displayed remaining power of the battery pack 11 and the target remaining power.

[0142] In this embodiment, the remaining power difference is a positive number. Therefore, if the difference between the displayed remaining power at the previous moment and the target remaining power is negative, the absolute value of the difference is taken as the remaining power difference. If the difference between the displayed remaining power at the previous moment and the target remaining power is positive, the difference is taken as the remaining power difference.

[0143] Step S512 : Calculate the voltage difference between the voltage parameter of the single cell of the battery pack 11 and the target voltage parameter.

[0144] The target voltage parameter can vary depending on the charge and discharge state. When the battery pack is charging, the target voltage parameter is the cell voltage at the end of charging; when the battery pack is discharging, the target voltage parameter is the cell voltage at the end of discharging. Similarly, the voltage difference in this embodiment is a positive value. Therefore, when the difference between the voltage parameter of a single cell and the target voltage parameter is negative, the absolute value of the difference is taken as the voltage difference between the two. The target voltage parameter can be determined based on the cell performance parameters and is not limited to a specific embodiment.

[0145] Step S513: Determine a display correction coefficient according to the ratio between the remaining power difference and the voltage difference.

[0146] Since the calculation formulas for the voltage difference of the battery pack are different when it is in the charging state and the discharging state, the calculation of the display correction coefficient will also be different in the two states.

[0147] When the battery pack is in the discharge state, the calculation formula of the display correction coefficient K1 is as follows:

[0148]

[0149] Where USoc(n-1) is the displayed remaining capacity at the previous moment. TargetSoc(n) is the current target remaining capacity. V(n) is the current cell voltage. In the discharge state, the minimum cell voltage is used as V(n). FullDsgVolt is the cell voltage at the end of discharge, i.e., the cell voltage when fully discharged.

[0150] It is understood that in the above embodiment, when correcting the displayed remaining power, the greater the difference between the displayed remaining power and the target remaining power, the faster the correction speed. The closer the current voltage parameter is to the discharge cut-off voltage, the faster the correction speed.

[0151] When the battery pack is in the charging state, the calculation formula of the display correction coefficient K2 is as follows:

[0152]

[0153] Where USoc(n-1) is the displayed remaining capacity at the previous moment. TargetSoc(n) is the current target remaining capacity. V(n) is the current cell voltage. When charging, the maximum cell voltage is used as V(n). FullChgVolt is the cell voltage at the end of charging, i.e., the cell voltage when fully charged.

[0154] It is understood that in the above embodiment, when correcting the displayed remaining power, the greater the difference between the displayed remaining power and the target remaining power, the faster the correction speed. The closer the current voltage parameter is to the discharge cut-off voltage, the faster the correction speed.

[0155] Step S314: Determine the current remaining power according to the correction coefficient and the accumulated charge and discharge power.

[0156] In some embodiments, the cumulative charge and discharge power is calculated using the ampere-hour integration method. Therefore, the cumulative charge and discharge power can be expressed as: Where Δt is the update period for displaying the remaining battery capacity, which is typically the same as the current sampling interval. In other embodiments, it can also be greater than the current sampling interval. Q is the rated capacity of the corresponding battery cell, and I(n) is the current sampling current of the single battery cell.

[0157] In some embodiments, when the battery pack 11 is in a discharging state, the formula for calculating and displaying the remaining power can be:

[0158]

[0159] Among them, USoc(n) is the displayed remaining power at the current moment; USoc(n-1) is the displayed remaining power at the previous moment.

[0160] In some embodiments, when the battery pack 11 is in a charging state, the formula for calculating and displaying the remaining power can be:

[0161]

[0162] Among them, USoc(n) is the displayed remaining power at the current moment n; USoc(n-1) is the displayed remaining power at the previous moment.

[0163] The present application provides a method for determining the remaining power, including: obtaining the charge and discharge parameters of each single cell in the battery pack 11; obtaining the current capacity retention rate of the battery pack 11 when the charge and discharge parameters meet the correction trigger condition; determining the minimum remaining power of the single cell of the battery pack 11 according to the capacity retention rate and the charge and discharge parameters; determining the target remaining power of the battery pack 11 according to the minimum remaining power of the single cell and the capacity retention rate; and determining the displayed remaining power at the current moment according to the target remaining power. The present application can effectively improve the accuracy of determining the remaining power of the energy storage system through the three-level correction of the minimum remaining power of the single cell, the target remaining power, and the displayed remaining power. In addition, the present application solution adds calibration of the remaining power of the single cell, so that calibration can be performed even if it is not fully charged or discharged.

[0164] Another embodiment of the present application further provides an energy storage device 10 , which includes a processor and a memory 13 , wherein the processor is configured to implement the above-mentioned remaining power determination method when executing a computer program stored in the memory 13 .

[0165] It can be understood that the device of this embodiment corresponds to the method for determining the remaining power of the above embodiment, and the optional items in the above embodiment are also applicable to this embodiment, so they will not be repeated here.

[0166] Among them, the processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including a central processing unit (CPU), a graphics processing unit (GPU) and a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or at least one of other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc., which can implement or execute the disclosed methods, steps and logic block diagrams in the embodiments of the present application.

[0167] The memory 13 may be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. The memory 13 is used to store computer programs, and the processor may execute the computer programs accordingly after receiving an execution instruction.

[0168] The present application also provides a computer-readable storage medium for storing a computer program used in the energy storage device 10. For example, the computer-readable storage medium may include, but is not limited to, various media capable of storing program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0169] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or flowchart, and the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0170] In addition, the functional modules or units in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0171] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a smart phone, personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0172] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A method for determining remaining power, characterized in that: include: Obtain the charge and discharge parameters of each single cell in the battery pack; When the charge and discharge parameters meet the correction trigger condition, obtaining the current capacity retention rate of the battery pack; Determining the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the charge and discharge parameters; Determining a target remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate; The displayed remaining power at the current moment is determined according to the target remaining power.

2. The method according to claim 1, characterized in that The acquiring of the charge and discharge parameters of each single cell in the battery pack includes current parameters and temperature parameters of the single cell; When the charge and discharge parameters meet the correction trigger condition, obtaining the current capacity retention rate of the battery pack includes: The capacity retention rate is determined according to the current parameters and temperature parameters of the single battery cell.

3. The method according to claim 1, characterized in that The acquiring of the charge and discharge parameters of each single cell in the battery pack includes current parameters and voltage parameters of the single cell; The method further comprises: When the battery pack is in a discharging state, if there is a single cell whose voltage parameter is within a preset correction voltage range, confirming that the charge and discharge parameters meet the correction trigger condition; and / or, When the battery pack is in a charging state, if the current parameter of a single cell is within a preset correction current range, it is confirmed that the charge and discharge parameters meet the correction trigger condition.

4. The method according to claim 3, characterized in that The determining of the minimum remaining power of a single cell of the battery pack according to the capacity retention rate and the charge and discharge parameters includes: When the battery pack is in a discharging state, determining the minimum remaining power of the battery pack cells according to the minimum voltage of the battery pack cells, the discharge correction parameter threshold, and the capacity retention rate; and / or, When the battery pack is in a charging state, the remaining capacity difference of each single cell in the battery pack is obtained, and the minimum remaining capacity of the single cell of the battery pack is determined according to the remaining capacity difference, the capacity retention rate, the charging correction parameter threshold and the current parameter.

5. The method according to claim 4, characterized in that The discharge correction parameter thresholds include a discharge start correction remaining capacity, a discharge exit correction remaining capacity, a discharge start correction voltage value, and a discharge exit correction voltage value; and / or, The charging correction parameter thresholds include a charging start correction remaining capacity, a charging exit correction remaining capacity, a charging start correction current value, and a charging exit correction current value.

6. The method according to claim 1, characterized in that The determining the target remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate includes: Calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell; Calculating the actual maximum capacity of the battery pack according to the capacity retention rate; The target remaining power is obtained according to a ratio of the available remaining power to the actual maximum capacity.

7. The method according to claim 6, characterized in that The calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell includes: When the battery pack is in a discharging state, calculating the current available remaining power of the battery pack according to the minimum remaining power of the single cell and the capacity retention rate; and / or, When the battery pack is in a charging state, the minimum remaining power of the single cell is used as the current available remaining power of the battery pack.

8. The method according to claim 6, characterized in that Calculating the current actual maximum capacity of the battery pack according to the capacity retention rate includes: Obtaining the remaining capacity difference of each single cell in the battery pack; The current actual maximum capacity of the battery pack is calculated according to the remaining capacity difference and the capacity retention rate.

9. The method according to claim 1, characterized in that The determining the displayed remaining power at the current moment according to the target remaining power includes: Calculating the difference between the displayed remaining power of the battery pack at the last moment and the target remaining power; Calculating a voltage difference between a voltage parameter of a single cell of the battery pack and a target voltage parameter; determining a display correction coefficient according to a ratio between the remaining power difference and the voltage difference; The displayed remaining power at the current moment is determined according to the display correction coefficient and the accumulated charge and discharge power.

10. An energy storage device, characterized in that: The energy storage device includes a processor and a memory, and the processor is used to implement the remaining power determination method according to any one of claims 1 to 9 when executing the computer program stored in the memory.

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