Battery equalization method, energy storage device and storage medium

Abstract

The invention provides a battery equalization method, an energy storage device and a storage medium, the battery equalization method is applied to the energy storage device, the energy storage device comprises a battery pack, the battery pack comprises a plurality of single batteries, and the method comprises the following steps: obtaining current information and voltage information of each single battery in a charging state; if it is determined that the plurality of single batteries meet a preset condition based on the current information, generating an incremental capacity curve corresponding to each single battery; determining a target battery according to the incremental capacity curve, wherein the target battery is the battery with the lowest capacity in the battery pack; and determining an equalization strategy of the battery pack according to a target capacity difference value between the target battery and each non-target battery in the battery pack under the condition that the charging of the battery pack is ended. The method can improve the equalization efficiency.

Description

Technical Field

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

[0002] The battery pack is composed of multiple single cells. Due to the manufacturing differences of the single cells and the influence of external factors, the battery imbalance of each single cell may occur after long-term use. In order to solve the problem of battery imbalance, passive balancing (Passive Balancing) or active balancing (Active Balancing) technology is usually used to manage the battery pack. Passive balancing achieves balancing by consuming power, and active balancing achieves balancing by transferring power. However, these two balancing technologies are prone to over-balancing or under-balancing problems, and cannot accurately control the power required for balancing, resulting in low balancing efficiency. Summary of the invention

[0003] The embodiments of the present application disclose a battery balancing method, an energy storage device, and a storage medium, which solve the technical problem that the related balancing technology has low balancing efficiency due to the inability to accurately control the amount of electricity required for balancing.

[0004] The present application provides a battery balancing method, which is applied to an energy storage device, wherein the energy storage device includes a battery pack, and the battery pack includes a plurality of single cells. The method includes: obtaining current information and voltage information of each single cell under a charging state; if it is determined based on the current information that the plurality of single cells meet a preset condition, generating an incremental capacity curve corresponding to each single cell; determining a target battery according to the incremental capacity curve, wherein the target battery is the battery with the lowest capacity in the battery pack; and determining a balancing strategy for the battery pack according to a target capacity difference between the target battery and each non-target battery in the battery pack when charging of the battery pack is terminated.

[0005] In some embodiments of the present application, the determination of the target battery according to the incremental capacity curve includes: determining the characteristic value corresponding to each single cell based on the incremental capacity curve, the characteristic value being the maximum characteristic peak value in the incremental capacity value set corresponding to each single cell within a preset range; obtaining the time of recording the characteristic value corresponding to each single cell; determining the incremental capacity curve where the characteristic value corresponding to the latest time is located as the target curve; and taking the single cell corresponding to the target curve as the target battery. In some embodiments of the present application, the generation of the incremental capacity curve corresponding to each single cell includes: determining the first voltage value at the first moment and the second voltage value at the second moment based on the voltage information; calculating the first voltage difference between the first voltage value and the second voltage value; if the first voltage difference reaches a preset threshold, obtaining the first capacity value at the first moment and the second capacity value at the second moment; calculating the first capacity difference between the first capacity value and the second capacity value; and recording the incremental capacity value determined according to the first capacity difference and the first voltage difference on the incremental capacity curve.

[0006] In some embodiments of the present application, the method also includes: if the first voltage difference does not reach the preset threshold, confirming the third voltage value at the third moment; calculating the second voltage difference between the first voltage value and the third voltage value; if the second voltage difference reaches the preset threshold, obtaining the third capacity value at the third moment; calculating the second capacity difference between the first capacity value and the third capacity value; and recording the incremental capacity value determined based on the second capacity difference and the second voltage difference on the incremental capacity curve.

[0007] In some embodiments of the present application, the target capacity difference between the target battery and each other single cell in the battery pack includes: obtaining the target capacity value of the characteristic value corresponding to the target curve; and calculating the target capacity difference based on the target capacity value and the capacity value of each non-target battery.

[0008] In some embodiments of the present application, the method further includes: determining a first balancing time required to balance the battery group based on a preset first type balancing strategy; during the first balancing time, controlling each of the non-target batteries to release a corresponding capacity according to the target capacity difference.

[0009] In some embodiments of the present application, the method further includes: determining a second balancing time required to balance the battery group based on a preset second type of balancing strategy; during the second balancing time, controlling the capacity transfer between the single cells of the battery group until the capacity corresponding to each single cell is the same.

[0010] In some embodiments of the present application, the method further includes: determining a current multiplier based on the current information; if the temperature of the battery pack is within a preset temperature range and the current multiplier is greater than or equal to a preset current multiplier, determining that the multiple single cells meet the preset conditions.

[0011] The present application also provides an energy storage device, which includes a processor and a memory, and the processor is used to implement the battery balancing method when executing a computer program stored in the memory.

[0012] The present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the battery balancing method is implemented.

[0013] The battery balancing method provided in the present application is applied to an energy storage device, which includes a battery pack, and the battery pack includes multiple single cells. The current information and voltage information of each single cell under the charging state are obtained to monitor the state of each single cell in real time. If it is determined based on the current information that multiple single cells meet the preset conditions, an incremental capacity curve corresponding to each single cell is generated, and the relationship between the capacity value and the voltage value of each single cell is recorded using the corresponding incremental capacity curve. The target battery is determined according to the incremental capacity curve, and the target battery is the battery with the lowest capacity in the battery pack. The target battery can be effectively screened out through the incremental capacity curve. Therefore, when the battery pack ends charging, the balancing strategy of the battery pack is determined according to the target capacity difference between the target battery and each non-target battery in the battery pack. The battery balancing method provided in the present application can use the target capacity difference to accurately control the amount of electricity required for balancing and improve the efficiency of balancing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the energy storage device provided in the embodiment of the present application.

[0015] Figure 2 It is a flow chart of a battery balancing method provided in an embodiment of the present application.

[0016] Figure 3 It is a schematic diagram of the incremental capacity curve provided in the embodiment of the present application.

[0017] Figure 4 This is a flow chart for determining a target battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] To facilitate understanding, some illustrations of concepts related to the embodiments of the present application are given by way of example for reference.

[0019] It should be noted that in this application, "at least one" means one or more, and "more than one" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0020] As an important energy storage device, lithium iron phosphate batteries are widely used in mobile devices, electric vehicles, energy storage systems and other fields. Lithium iron phosphate battery packs are composed of multiple single cells. Due to a series of factors such as manufacturing differences of single cells, the influence of external factors, and the self-discharge rate during use, long-term use will cause battery imbalance problems among the single cells. For example, deviations in parameters such as voltage and capacity between single cells occur. This type of battery imbalance problem will not only reduce the overall performance of the battery pack, but also accelerate the attenuation of the single cells, shorten the service life of the battery pack, and even cause safety problems. Therefore, the balance of the battery pack is particularly important.

[0021] Battery pack balancing refers to the process of adjusting the charging state of each single cell in the battery pack to ensure that their voltage and capacity are evenly distributed. Battery pack balancing can extend the service life of the battery pack and improve the overall performance. There are two main battery pack balancing methods: passive balancing and active balancing.

[0022] Passive balancing is simpler than active balancing. It connects a resistor in parallel to each single cell. When the single cell is charged, the resistor consumes excess energy, thereby gradually making the voltage of all single cells consistent. When the voltage of any single cell exceeds the preset voltage threshold, the corresponding resistor begins to conduct, and energy is released in the form of heat. Passive balancing has the characteristics of simple operation and low cost, but it also has certain disadvantages. For example, because the excess energy is converted into heat and consumed in an inefficient way, heat is generated during passive balancing, and additional heat dissipation measures may be required.

[0023] Active balancing is more efficient than passive balancing. It uses circuits (such as switches, inductors, capacitors, etc.) to directly transfer energy between cells instead of consuming it like passive balancing. Active balancing can be done in both directions, transferring energy from high-voltage cells to low-voltage cells, and from low-voltage cells to high-voltage cells. Active balancing is highly efficient, but the circuit is more complex, more expensive, and more difficult to implement.

[0024] However, these two balancing technologies are prone to over-balancing or under-balancing problems and cannot accurately control the amount of electricity required for balancing, resulting in low balancing efficiency.

[0025] In order to solve the technical problem that the related balancing technology cannot accurately control the amount of electricity required for balancing, resulting in low balancing efficiency. The embodiment of the present application provides a battery balancing method, energy storage device and storage medium, which can accurately control the amount of electricity required for balancing and improve the efficiency and accuracy of balancing. The structure of the energy storage device is first described below.

[0026] Figure 1 Schematic diagram of the structure of the energy storage device provided in the embodiment of the present application. Figure 1 As shown, in the embodiment of the present application, the energy storage device 10 includes but is not limited to: a memory 102 connected via a communication bus 101, at least one processor 103, a battery management unit 104 and a battery pack 105.

[0027] The energy storage device 10 may be any device with energy storage function, such as a vehicle-mounted energy storage device, a household energy storage device, a mobile energy storage device, etc. The embodiment of the present application does not impose any limitation on the specific type of the energy storage device 10.

[0028] The memory 102 may include one or more random access memories (RAM) and one or more non-volatile memories (NVM). The random access memory can be directly read and written by the processor 103, and can be used to store executable programs (such as machine instructions) of the operating system or other running programs, and can also be used to store user and application data. The random access memory may include static random-access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), etc.

[0029] The non-volatile memory may also store executable programs and user and application data, etc., and may be loaded into the random access memory in advance for direct reading and writing by the processor 103. The non-volatile memory may include a disk storage device and a flash memory.

[0030] The memory 102 is used to store one or more computer programs. The one or more computer programs are configured to be executed by the processor 103. The one or more computer programs include multiple instructions, and when the multiple instructions are executed by the processor 103, the battery balancing method executed on the energy storage device 10 can be implemented.

[0031] In other embodiments, the energy storage device 10 further includes an external memory interface for connecting to an external memory to expand the storage capacity of the energy storage device 10 .

[0032] The processor 103 may include one or more processing units, for example, the processor 103 may include an application processor (AP), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0033] The processor 103 provides computing and control capabilities. For example, the processor 103 is used to execute a computer program stored in the memory 102 to implement the above-mentioned battery balancing method.

[0034] The battery management unit 104 includes a battery management system (BMS), wherein the BMS is a management system for monitoring the operating status of the battery pack 105 . The BMS obtains dynamic data of the battery pack 105 during operation, such as current information or voltage information of the battery pack 105 .

[0035] The battery pack 105 is a battery group composed of a plurality of single batteries.

[0036] The indication Figure 1 This is only an example of the energy storage device 10 and does not constitute a limitation of the energy storage device 10. The energy storage device 10 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the energy storage device 10 may also include input and output devices, display screens, etc.

[0037] Figure 2 is a flow chart of a battery balancing method provided in an embodiment of the present application, which is applied to energy storage devices (such as Figure 1According to different requirements, the order of the steps in the flowchart can be changed, and some steps can be omitted.

[0038] Step S201, obtaining current information and voltage information of each single battery in a charging state.

[0039] In some embodiments of the present application, when the battery pack of the energy storage device is low in power, the energy storage device can be charged so that the battery pack converts external energy into electrical energy for storage while being charged. Alternatively, the energy storage device is connected to the photovoltaic module to store the electrical energy generated by the photovoltaic module so that it can be released and used when needed.

[0040] In some embodiments of the present application, the energy storage device can use the battery management unit to collect the operating data of the battery pack during the charging and discharging process. The operating data may include the operating temperature, voltage information, current information, state of charge (SOC), capacity, charge and discharge power, charge and discharge time, battery health status, etc. of the battery pack. When the battery pack is charging, the battery management unit can be used to collect current information and voltage information.

[0041] Step S202: if it is determined based on the current information that a plurality of single cells meet a preset condition, an incremental capacity curve corresponding to each single cell is generated.

[0042] In some embodiments of the present application, it can be determined whether the preset conditions are met based on the current multiplier and the temperature of the battery pack. The current multiplier is determined based on the current information, and the current multiplier is used to describe the change of the current in the circuit. The original current value can be obtained from the current information, and the multiple can be preset, so that the product of the original current value and the multiple can be calculated as the current multiplier based on the original current value and the multiple. Among them, the original current value represents the current value in the circuit, and the multiple represents the proportional factor of enlargement or reduction. The temperature of the battery pack can be detected by the battery management unit.

[0043] In some embodiments of the present application, after the current rate and the temperature of the battery pack are determined, if the temperature of the battery pack is within a preset range and the current rate is greater than or equal to the preset current rate, it is determined that the plurality of single cells meet the preset conditions. The preset range may be set according to actual conditions. The preset conditions may also be set according to actual application scenarios, which are not limited by the present application.

[0044] If the temperature of the battery pack is not within the preset range or the current rate is less than the preset current rate, it is determined that the multiple single cells do not meet the preset conditions. If the temperature of the battery pack is not within the preset range, it means that the temperature of the battery pack is too high or too low. If the current rate is less than the preset current rate, it means that the current output by the battery pack is much less than its rated current.

[0045] In some embodiments of the present application, when it is determined that the preset conditions are met, it indicates that the conditions for drawing the incremental capacity curve are met. The incremental capacity curve is a curve obtained by analyzing the voltage-capacity change relationship of the battery pack during the charging and discharging process, which can also be called an IC (Incremental Capacity) curve. Figure 3 Describe the process of drawing incremental capacity curves.

[0046] Figure 3 Schematic diagram of the incremental capacity curve provided in the embodiment of the present application. Figure 3 As shown, point A, point B and point C are points corresponding to the incremental capacity values ​​on the incremental capacity curve. Among them, the points on the incremental capacity curve are calculated based on the current information and voltage information. Therefore, after the current information and voltage information are collected, pre-processing can be performed first. Pre-processing may include data calibration, data cleaning and other processing, which is not limited in this application. After determining the points on the incremental capacity curve, the incremental capacity curve can also be smoothed to improve the accuracy of data processing and facilitate subsequent analysis of the incremental capacity curve.

[0047] In some embodiments of the present application, voltage information is recorded in real time, and a first voltage value at a first moment and a second voltage value at a second moment are determined based on the voltage information, wherein the first moment may represent the moment when the voltage information starts to be recorded, and the second moment may be an adjacent moment, or a moment after a preset time length from the first moment, and the present application is not limited to this. Calculate the first voltage difference between the first voltage value and the second voltage value. If the first voltage difference is greater than or equal to the preset threshold, obtain the first capacity value recorded at the first moment and the second capacity value recorded at the second moment. Calculate the first capacity difference between the first capacity value and the second capacity value. On the incremental capacity curve, record the incremental capacity value determined based on the first capacity difference and the first voltage difference.

[0048] In one example, a first voltage difference (V2-V1) between a first voltage value V1 and a second voltage value V2 is calculated, and a first capacity difference (Q2-Q1) between a first capacity value Q1 and a second capacity value Q2 is calculated, and the following can be obtained: Figure 3 The incremental capacity value of point A = d(Q2-Q1) / d(V2-V1).

[0049] If the first voltage difference is less than the preset threshold, obtain the voltage information at the next moment, for example, obtain the third voltage value at the third moment. Calculate the second voltage difference between the first voltage value and the third voltage value. If the second voltage difference is greater than or equal to the preset threshold, obtain the third capacity value at the third moment. Calculate the second capacity difference between the first capacity value and the third capacity value. On the incremental capacity curve, record the incremental capacity value determined according to the second capacity difference and the second voltage difference.

[0050] In one example, a second voltage difference (V3-V1) between the first voltage value V1 and the third voltage value V3 is calculated, and a second capacity difference (Q3-Q1) between the first capacity value Q1 and the third capacity value Q3 is calculated. Then, the following can be calculated: Figure 3 The incremental capacity value of point A = d(Q3-Q1) / d(V3-V1).

[0051] In other embodiments, if the second voltage difference is still smaller than the preset threshold, the voltage information at the next moment can be obtained, and the above process can be repeated until the calculated voltage difference is greater than or equal to the preset threshold, and the incremental capacity value of point A is recorded.

[0052] After recording the incremental capacity value corresponding to point A, the incremental capacity value of point B can be calculated. Calculate the third voltage difference (V5-V4) between the fourth voltage value V4 at the fourth moment and the fifth voltage value V5 at the fifth moment. If the third voltage difference (V5-V4) is greater than or equal to the preset threshold, obtain the fourth capacity value at the fourth moment and the fifth capacity value at the fifth moment. Calculate the third capacity difference (Q5-Q4) between the fourth capacity value Q4 and the fifth capacity value Q5. Then you can calculate Figure 3 The incremental capacity value of point B = d(Q5-Q4) / d(V5-V4).

[0053] The above is just an example of calculating the incremental capacity value of point A and point B. In actual application scenarios, there are many points between point A and point B. When the voltage difference calculated based on the voltage information reaches a preset threshold, the incremental capacity value is calculated to draw an incremental capacity curve according to the calculated incremental capacity value.

[0054] Step S203, determining the target battery according to the incremental capacity curve.

[0055] In some embodiments of the present application, the target battery is determined based on the incremental capacity value on the recorded incremental capacity curve. The target battery may be a battery with a slower charging speed in the battery pack. When the battery pack is finished charging, the target battery has the lowest capacity. The specific process of determining the target battery based on the incremental capacity curve can be found in the following Figure 4 The embodiment shown.

[0056] Step S204, when the battery pack is finished charging, a balancing strategy for the battery pack is determined according to a target capacity difference between the target battery and each non-target battery in the battery pack.

[0057] In some embodiments of the present application, when the battery pack finishes charging, the capacity of each single cell in the battery pack can be obtained. After the target battery is determined, the target capacity difference between the target battery and each non-target battery in the battery pack is calculated based on the capacity of the target battery and the capacity of each non-target battery. Thus, the time required for balancing is calculated according to the target capacity difference, and the balancing strategy is determined according to the target capacity difference and the time. The balancing strategy may include a first type of balancing strategy and a second type of balancing strategy. Among them, the first type of balancing strategy may be a passive balancing strategy, and the second type of balancing strategy may be an active balancing strategy.

[0058] In some embodiments of the present application, based on the first type of balancing strategy, the first balancing time required for balancing the battery group is determined. The first balancing time can be calculated based on the current information and the target capacity difference, which is the time for executing the first type of balancing strategy. During the first balancing time, each non-target battery is controlled to release the corresponding capacity according to the target capacity difference. Through the first balancing time and the target capacity difference, the capacity to be released can be accurately controlled, thereby improving the balancing efficiency and accuracy of the first type of balancing strategy.

[0059] In some embodiments of the present application, based on the second type of balancing strategy, the second balancing time required for balancing the battery group is determined. The second balancing time can be calculated based on the current information and the target capacity difference, which is the time for executing the second type of balancing strategy. During the second balancing time, the capacity transfer between the single cells of the battery pack is controlled until the capacity corresponding to each single cell is the same. Through the second balancing time and the target capacity difference, the capacity to be transferred can be accurately controlled, which reduces the complexity of the second type of balancing strategy and improves the universality of the second type of balancing strategy.

[0060] In an embodiment of the present application, the current information and voltage information of each single cell under the charging state are obtained so as to monitor the state of each single cell in real time. If it is determined based on the current information that multiple single cells meet the preset conditions, an incremental capacity curve corresponding to each single cell is generated, and the relationship between the capacity value and the voltage value of each single cell is recorded using the corresponding incremental capacity curve. The target battery is determined according to the incremental capacity curve, and the target battery is the battery with the lowest capacity in the battery pack. The target battery can be effectively screened out through the incremental capacity curve. Therefore, when the battery pack finishes charging, the balancing strategy of the battery pack is determined according to the target capacity difference between the target battery and each non-target battery in the battery pack. The battery balancing method provided in the present application can use the target capacity difference to accurately control the amount of electricity required for balancing and improve the efficiency of balancing.

[0061] Figure 4 is a flow chart for determining a target battery provided in an embodiment of the present application, such as Figure 4 As shown, the following steps are included.

[0062] S401, determining a characteristic value corresponding to each single cell based on the incremental capacity curve.

[0063] In some embodiments of the present application, the incremental capacity curve is a curve obtained by analyzing the voltage-capacity change relationship of the battery pack during the charging and discharging process. Therefore, the incremental capacity curve records the changes in voltage and capacity. The characteristic value represents the state of the single cell when it is charged to a certain stage, which is the maximum characteristic peak value in the incremental capacity value set within a preset range corresponding to each single cell. Based on the generation time of the incremental capacity curve, the regional peak is determined within each set area. Based on the generation time, the peak values ​​of two adjacent areas are compared. If the first area is larger than the peak value of the second area, the regional peak value corresponding to the first area is used as the characteristic value. If the first area is smaller than the regional peak value of the second area, the regional peak value corresponding to the second area is used as the characteristic value. Among them, the regional peak recording time of the first area is earlier than the regional peak recording time of the second area.

[0064] In one example, in order to improve the efficiency of obtaining the characteristic value, the characteristic value can be determined during the process of generating the incremental capacity curve. Figure 3 , assuming that Figure 3 Point A, point B and point C are all regional peaks. The regional peaks of point A and point B are compared. Since the regional peak of point B is greater than the regional peak of point A, the regional peak of point B is further compared with the regional peak of point C. Figure 3 As shown, the regional peak value of point C is greater than the regional peak value of point B, and the area where point C is located is the last area divided, then the incremental capacity value corresponding to point C is used as the characteristic value.

[0065] In another example, in order to reduce the comparison steps of the values ​​recorded by the incremental capacity curve, the characteristic value can be determined after the battery pack is charged. Based on the curve characteristics of the incremental capacity curve, multiple candidate peaks are determined, and the largest candidate peak is selected from the multiple candidate peaks. The incremental capacity value recorded by the largest candidate peak is the largest. Figure 3 As shown, the multiple candidate peaks include the recorded peaks corresponding to points A, B and C. Point C records the largest candidate peak, and the incremental capacity value corresponding to point C is used as the feature value.

[0066] S402, obtaining the time for recording the characteristic value corresponding to each single cell.

[0067] In some embodiments of the present application, due to differences between single cells, the time for each single cell to reach the characteristic value may be different. Therefore, after determining the characteristic value corresponding to each single cell, the time corresponding to the characteristic value recorded for each single cell can be obtained to provide a basis for evaluating the capacity difference corresponding to each single cell.

[0068] S403, determining the incremental capacity curve where the characteristic value corresponding to the latest time is located as the target curve.

[0069] In some embodiments of the present application, the time corresponding to the recording of the characteristic value of each single cell is compared. The later the time, the later the characteristic value of the single cell appears, and the larger the characteristic value of the corresponding single cell and the lower the capacity. The incremental capacity curve corresponding to the characteristic value of the latest time is used as the target curve, which is the incremental capacity curve corresponding to the single cell with the lowest capacity.

[0070] In one example, assuming that there are single cell 1 and single cell 2, the incremental capacity curve 1 corresponding to single cell 1 and the incremental capacity curve 2 corresponding to single cell 2 are obtained. Assuming that the incremental capacity curve 1 records the characteristic value at 1 o'clock and the incremental capacity curve 2 records the characteristic value at 1 o'clock and 2 minutes, it means that the charging speed of single cell 2 is lower than that of single cell 1, and the incremental capacity curve 2 is used as the target curve.

[0071] In another embodiment of the present application, the cumulative values ​​of the capacity values ​​corresponding to the multiple points recorded in the incremental capacity curve corresponding to each single cell can also be compared, specifically, the cumulative value of the capacity reaching the characteristic point corresponding to the characteristic value is calculated. The larger the cumulative value of the capacity, the longer the recording time, and the slower the charging speed of the corresponding single cell, and the incremental capacity curve where the maximum cumulative value of the capacity is located is used as the target curve.

[0072] S404, taking the single cell corresponding to the target curve as the target battery.

[0073] In some embodiments of the present application, since the target capacity value of the single cell corresponding to the target curve is the lowest, the single cell with the lowest target capacity value is used as the target battery. The subsequent balancing strategy is executed based on the single cell with the lowest target capacity value, so that the capacity to be released can be accurately controlled.

[0074] In the embodiments of the present application, the target battery is determined by the incremental capacity curve, so that the battery with the lowest capacity can be accurately located, thereby improving the balancing efficiency of the battery pack and the overall performance of the battery pack.

[0075] In other embodiments of the present application, determining the target battery may also include: monitoring the voltage of each single cell in real time through the battery management system BMS, estimating the capacity of each single cell through the recorded voltage, and determining the single cell with the lowest capacity as the target battery. In addition, the charge and discharge current of each single cell may be recorded through the BMS, and the charge and discharge current of each single cell may be integrated to obtain the remaining capacity of each single cell. The single cell with the lowest capacity is determined as the target battery based on the remaining capacity.

[0076] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. The computer program includes program instructions. The method implemented when the program instructions are executed can refer to the methods in the above-mentioned embodiments of the present application.

[0077] The computer-readable storage medium may be an internal memory of the energy storage device described in the above embodiment, such as a hard disk or memory of the energy storage device. The computer-readable storage medium may also be an external storage device of the energy storage device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc., equipped on the energy storage device.

[0078] In some embodiments, the computer-readable storage medium may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function, etc.; the data storage area may store data created according to the use of the energy storage device, etc.

[0079] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0080] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0081] In the embodiments provided in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0082] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0083] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery balancing method, applied to energy storage equipment, characterized in that: The energy storage device comprises a battery pack, the battery pack comprises a plurality of single cells, and the method comprises: Obtain current information and voltage information of each single battery under charging status; If it is determined based on the current information that the plurality of single cells meet a preset condition, generating an incremental capacity curve corresponding to each single cell; Determine a target battery according to the incremental capacity curve, the target battery being the battery with the lowest capacity in the battery pack; When the battery pack is finished charging, a balancing strategy for the battery pack is determined according to a target capacity difference between the target battery and each non-target battery in the battery pack.

2. The battery equalization method according to claim 1, characterized in that: The determining of the target battery according to the incremental capacity curve comprises: Based on the incremental capacity curve, determining a characteristic value corresponding to each single battery, wherein the characteristic value is a maximum characteristic peak value in a set of incremental capacity values ​​corresponding to each single battery and within a preset range; Obtain and record the time when each single cell corresponds to the characteristic value; Determine the incremental capacity curve where the characteristic value corresponding to the latest time is located as the target curve; The single cell corresponding to the target curve is used as the target cell.

3. The battery equalization method according to claim 1, characterized in that: The generating the incremental capacity curve corresponding to each single cell includes: Based on the voltage information, determining a first voltage value at a first moment and a second voltage value at a second moment; Calculating a first voltage difference between the first voltage value and the second voltage value; If the first voltage difference reaches a preset threshold, obtaining a first capacity value at the first moment and a second capacity value at the second moment; Calculating a first capacity difference between the first capacity value and the second capacity value; On the incremental capacity curve, an incremental capacity value determined according to the first capacity difference value and the first voltage difference value is recorded.

4. The battery equalization method according to claim 3, characterized in that: The method further comprises: If the first voltage difference does not reach the preset threshold, determining a third voltage value at a third moment; Calculating a second voltage difference between the first voltage value and the third voltage value; If the second voltage difference reaches the preset threshold, obtaining a third capacity value at the third moment; Calculating a second capacity difference between the first capacity value and the third capacity value; On the incremental capacity curve, an incremental capacity value determined according to the second capacity difference value and the second voltage difference value is recorded.

5. The battery equalization method according to claim 2, characterized in that: The target capacity difference between the target battery and each other single battery in the battery pack includes: Obtaining a target capacity value of a characteristic value corresponding to the target curve; The target capacity difference is calculated according to the target capacity value and the capacity value of each non-target battery.

6. The battery equalization method according to claim 5, characterized in that: The method further comprises: Based on a preset first type of balancing strategy, determining a first balancing time required to balance the battery group; During the first balancing time, each of the non-target batteries is controlled to release corresponding capacity according to the target capacity difference.

7. The battery equalization method according to claim 5, characterized in that: The method further comprises: Based on a preset second type of balancing strategy, determining a second balancing time required to balance the battery group; During the second balancing time, the capacity is controlled to be transferred between the single cells of the battery pack until the capacity corresponding to each single cell is the same.

8. The battery equalization method according to claim 1, characterized in that: The method further comprises: determining a current multiplier based on the current information; If the temperature of the battery pack is within a preset temperature range and the current magnification is greater than or equal to a preset current magnification, it is determined that the plurality of single cells meet the preset condition.

9. An energy storage device, characterized in that: The energy storage device comprises a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement the battery balancing method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, the battery balancing method according to any one of claims 1 to 8 is implemented.

Images