SOC balancing method, device and electronic equipment for energy storage system

Abstract

The present application discloses a SOC balancing method, device and electronic equipment for an energy storage system. The method sets three balancing control strategies. The first balancing strategy performs inter-group SOC balancing on all battery groups, then judges the battery groups after the first balancing and selects a first target battery group set to be balanced. The second balancing strategy performs intra-group SOC balancing on the battery groups in the first target battery group set, then judges the battery groups after the second SOC balancing and selects a second target battery group set to be balanced. The third balancing strategy performs inter-group SOC balancing on the battery groups in the second target battery group set. Through three SOC balancings (two inter-group SOC balancings and one intra-group SOC balancing), gradual adjustment of the SOC can be achieved, so that the system can quickly and efficiently achieve SOC balancing to ensure that the battery always works in the best state, thereby reducing damage to the battery and extending its service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage systems, and particularly relates to a SOC balancing method, device and electronic equipment for an energy storage system. Background Art

[0002] Energy storage systems typically consist of a battery system, an energy storage converter (PCS), and an energy storage monitoring system (EMS). The battery system includes a battery stack and a battery management system (BMS). A battery stack is composed of several battery cells connected in series or in series-parallel to form a battery pack. Several battery packs are connected in series to form a battery pack, and several battery packs are connected in parallel to form a battery stack. The BMS manages each battery cell in the battery stack, ensuring that the state of charge (SOC) of each cell is roughly consistent and balanced.

[0003] At present, in energy storage system applications where multiple battery packs are used in parallel, the problem of SOC differences between battery packs caused by battery capacity decay is becoming increasingly prominent as the battery system is recycled. This is followed by a decline in system performance, or even unusable, requiring shutdown for maintenance, which results in loss of customer revenue.

[0004] In the existing technology, when adjusting the battery pack, the balancing technology generally only adjusts the battery groups in the battery pack, but cannot finely manage and adjust the battery cells. As a result, the SOC of each battery cell in the battery pack cannot be kept consistent, and the SOC imbalance between the battery cells will seriously affect the balance of the SOC between the battery packs, thereby affecting the overall balance of the entire energy storage system, and ultimately causing problems such as short system service life and poor balancing performance.

[0005] Therefore, how to design a fast, dynamic and efficient balancing method for energy storage systems is a technical problem to be solved. Summary of the Invention

[0006] Based on this, it is necessary to provide a SOC balancing method, device and electronic equipment for an energy storage system to address the problems of the existing technology.

[0007] In a first aspect, an embodiment of the present application provides a method for balancing the SOC of an energy storage system, comprising the following steps:

[0008] S1: performing a first SOC balancing on multiple battery packs of the energy storage system using a first balancing strategy;

[0009] S2: After the first SOC balancing is completed, the first SOCs of the multiple battery packs at the current moment are obtained to obtain a first SOC data set consisting of the first SOCs of the multiple battery packs;

[0010] S3: Determine whether the absolute difference between the first SOC of the plurality of battery packs and the first system average SOC is greater than a first preset threshold;

[0011] S4: In response to an absolute difference between the first SOC of the plurality of battery groups and the first system average SOC being greater than a first preset threshold, the battery group meeting this condition is recorded as a first target battery group, and all first target battery groups constitute a first target battery group set;

[0012] S5: performing a second SOC balancing on all first target battery packs in the first target battery pack set using a second balancing strategy;

[0013] S6: updating the SOCs of the plurality of battery packs to obtain a second SOC data set consisting of second SOCs of the plurality of battery packs;

[0014] S7: Determine whether the absolute difference between the second SOC of the plurality of battery packs and the second system average SOC is greater than a second preset threshold;

[0015] S8: In response to an absolute difference between the second SOC of the plurality of battery groups and the second system average SOC being greater than a second preset threshold, the battery group meeting this condition is recorded as a second target battery group, and all the second target battery groups constitute a second target battery group set;

[0016] S9: Perform a third SOC balancing on all second target battery groups in the second target battery set using a third balancing strategy.

[0017] Preferably, step S1 includes:

[0018] S11: Based on the total dispatch power of the energy storage system and the weight of each battery group, the target allocation power of each battery group is obtained;

[0019] S12: Allocating power to each battery pack based on the target allocated power of each battery pack to achieve a first SOC balance among the multiple battery packs;

[0020] The target distribution power of each battery pack is expressed by the following formula:

[0021] (1);

[0022] in, For the The target power distribution of each battery pack is is the total dispatching power of the energy storage system, is the total number of battery packs in the energy storage system, For the The weight of the battery pack, With the The target battery SOC of each battery pack is related.

[0023] Preferably, when the energy storage system is in a charging state, the weight of each battery pack is ; When the energy storage system is in the discharge state, the weight of each battery group = .

[0024] Preferably, the first preset threshold and the second preset threshold are obtained in the following manner:

[0025] Acquire third SOCs of the plurality of battery packs at a plurality of consecutive moments, obtaining a third SOC data set consisting of the third SOCs of the plurality of battery packs;

[0026] Based on the third SOC data set, obtaining the first preset threshold and the second preset threshold;

[0027] The second preset threshold is smaller than the first preset threshold.

[0028] Preferably, the first preset threshold and the second preset threshold are respectively expressed by the following formulas (2) and (3):

[0029] (2);

[0030] (3);

[0031] in, is the first preset threshold, is the second preset threshold, is the adjustment coefficient, To adjust the error, For all battery packs M The standard deviation of the SOC values at consecutive moments, It is expressed by formula (4):

[0032] (4);

[0033] in, For all battery packs The standard deviation of the SOC value at each moment is expressed by the following formula:

[0034] (5);

[0035] in, For the The moment The SOC of each battery pack, For the The average SOC of the energy storage system at a certain moment.

[0036] Preferably, step S5 includes:

[0037] S51: Divide each first target battery group in the first target battery group set into a high SOC set, a medium-high SOC set, a medium-low SOC set, and a low SOC set according to the SOC values of the battery cells;

[0038] S52: Transfer energy from the battery cells corresponding to the high SOC set to the battery cells corresponding to the low SOC set, and transfer energy from the battery cells corresponding to the medium-high SOC set to the battery cells corresponding to the medium-low SOC set, until the SOCs of the two battery cells in the first target battery group to which energy is being transferred are equal.

[0039] Preferably, step S9 includes:

[0040] S91: Transferring energy from the second target battery pack corresponding to the maximum SOC in the second target battery pack set to the second target battery pack corresponding to the minimum SOC until the SOCs of the two second target battery packs being transferred are equal;

[0041] S92: Repeat step S91 until energy transfer is completed between all second target battery groups.

[0042] Preferably, the adjustment error and the adjustment coefficient are both related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the energy storage system.

[0043] In a second aspect, an embodiment of the present application provides an SOC balancing device for an energy storage system, comprising:

[0044] A first balancing module, configured to perform a first SOC balancing on the multiple battery packs of the energy storage system using a first balancing strategy;

[0045] A data acquisition module is configured to acquire the first SOCs of the plurality of battery packs at the current moment after the first SOC balancing is completed, thereby obtaining a first SOC data set consisting of the first SOCs of the plurality of battery packs;

[0046] a first determination module, configured to determine whether an absolute difference between a first SOC of the plurality of battery packs and a first system average SOC is greater than a first preset threshold;

[0047] a first processing module, configured to, in response to an absolute difference between a first SOC of the plurality of battery groups and a first system average SOC being greater than a first preset threshold, record the battery group that meets the condition as a first target battery group, and all the first target battery groups constitute a first target battery group set;

[0048] A second balancing module, configured to perform a second SOC balancing on all first target battery packs in the first target battery pack set by adopting a second balancing strategy;

[0049] a data updating module, configured to update the SOCs of the plurality of battery packs and obtain a second SOC data set consisting of second SOCs of the plurality of battery packs;

[0050] a second determination module, configured to determine whether an absolute difference between a second SOC of the plurality of battery packs and a second system average SOC is greater than a second preset threshold;

[0051] a second processing module, configured to, in response to an absolute difference between the second SOC of the plurality of battery packs and a second system average SOC being greater than a second preset threshold, record the battery pack meeting this condition as a second target battery pack, and all the second target battery packs constitute a second target battery pack set;

[0052] The third balancing module is configured to perform a third SOC balancing on all second target battery groups in the second target battery set by adopting a third balancing strategy.

[0053] In a third aspect, an embodiment of the present application provides an electronic device, comprising:

[0054] processor;

[0055] a memory for storing instructions executable by the processor;

[0056] The processor is configured to read the executable instructions from the memory and execute the executable instructions to implement the method described in the first aspect above.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) Three balancing control strategies are set up. The first balancing strategy performs inter-group SOC balancing on all battery groups, and then judges the battery groups after the first SOC balancing to screen out the first target battery group set that needs to be balanced. The second balancing strategy performs intra-group SOC balancing on each battery group in the first target battery group set, and then judges the battery groups after the second SOC balancing to screen out the second target battery group set that needs to be balanced. The third balancing strategy performs inter-group SOC balancing on multiple battery groups in the second target battery group set. Through the three SOC balancing of the present invention (two inter-group SOC balancing and one intra-group SOC balancing), the SOC of the battery of the energy storage system can be gradually adjusted, so that the system can quickly and efficiently achieve SOC balancing to ensure that the system battery always works in the best state, thereby reducing damage to the battery and extending the battery life.

[0059] (2) The first balancing strategy is used to achieve SOC balancing among all battery packs, that is, rough balancing adjustment among battery packs. It does not require any data judgment or acquisition operation. As long as the energy storage system is connected, the balancing operation begins. The first balancing control strategy uses a weighted coefficient method to distribute the charge and discharge power of each battery pack so that the SOC of all battery packs is roughly consistent with its target SOC, thereby achieving a rough balance of SOC among battery packs, basically achieving the optimal state of the system, and helping to improve the charge and discharge efficiency;

[0060] (3) The second balancing strategy is used to achieve SOC balance within each battery pack of the first target battery pack. The balancing strategy dynamically adjusts the charge and discharge power of each battery cell in high, medium-high, medium-low and low segments based on the SOC of the battery cell of the battery pack, so that the power of the regulated battery cell remains roughly consistent, achieving SOC balance within the battery cluster, avoiding overcharging or undercharging of the battery cell, helping to improve charging and discharging efficiency, reduce the risk of thermal runaway, and further extend the life of the battery pack; at the same time, balancing the single cells can more effectively utilize the energy of the battery cluster, ensuring that each battery pack can reach its maximum storage capacity, thereby improving the energy utilization rate of the entire energy storage system;

[0061] (4) The third balancing strategy is used to achieve SOC balance between battery groups in the second target battery group, which can achieve SOC balance between battery groups; adjust the SOC between each battery cluster of the energy storage system, that is, finely adjust the SOC of the energy storage system. This strategy dynamically adjusts the charge and discharge power of each target battery cluster based on the second target battery group SOC. The battery group that does not need to be adjusted has reached the optimal state after two SOC adjustments. This adjustment can enable the battery group that needs to be adjusted to reach the optimal state quickly, thereby ensuring that multiple battery clusters of the energy storage system can be used in the best way, and the battery is not easily damaged, thereby improving the life of the system battery cluster; the SOC of multiple battery clusters all reach their respective target SOC, which further maximizes the system charge and discharge power, maximizes the utilization of electrical energy, reduces energy damage, and saves energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] A more complete understanding of the exemplary embodiments of the present invention can be obtained by referring to the following drawings. The drawings are intended to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present invention and do not constitute a limitation of the present invention. In the drawings, the same reference numerals generally represent the same components or steps.

[0063] Figure 1 A flow chart of a SOC balancing method for an energy storage system provided in an embodiment of the present application;

[0064] Figure 2A schematic diagram of an SOC balancing device for an energy storage system provided in an embodiment of the present application;

[0065] Figure 3 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0067] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0069] Example 1

[0070] Reference Figure 1 This embodiment discloses a SOC balancing method for an energy storage system, comprising the following steps:

[0071] S1: performing a first SOC balancing on multiple battery packs of the energy storage system using a first balancing strategy;

[0072] In this embodiment, after the energy storage system is connected, there is no need to obtain data from each battery pack, and the first SOC balancing is performed directly, so that the system can achieve a rough balance of SOC more quickly, that is, a rough adjustment is performed, and based on the results of the rough adjustment, subsequent steps are used to perform more refined adjustments so that the system reaches a completely balanced state.

[0073] Specifically, step S1 includes:

[0074] S11: Based on the total dispatch power of the energy storage system and the weight of each battery group, the target allocation power of each battery group is obtained;

[0075] S12: Allocating power to each battery pack based on the target allocated power of each battery pack to achieve a first SOC balance among the multiple battery packs;

[0076] The target distribution power of each battery pack is expressed by the following formula:

[0077] (1);

[0078] Specifically, when the energy storage system is in a charging state, the weight of each battery pack is , then formula (1) can be converted into the following formula:

[0079] ;

[0080] When the energy storage system is in the discharge state, the weight of each battery group = , at this time, formula (1) can be converted into the following formula:

[0081] ;

[0082] in, For the The target power distribution of each battery pack is The total dispatch charging power or discharging power of the energy storage system, collectively referred to as the total dispatch power; is the total number of battery packs in the energy storage system, For the The weight of the battery pack, With the The target battery SOC of each battery pack is related.

[0083] S2: After the first SOC balancing is completed, the first SOCs of the multiple battery packs at the current moment are obtained to obtain a first SOC data set consisting of the first SOCs of the multiple battery packs;

[0084] Specifically, the energy storage system includes PCS modules, N Battery packs (Battery pack 1, Battery pack 2, ... Battery pack N , this embodiment is described only by taking N=16 as an example), and each battery pack includes 16 battery cells (only for example).

[0085] After the first SOC equalization is completed, the SOC data of each battery pack is obtained, specifically including the first SOC data set consisting of the first SOC of battery packs 1-16: 、 、……、 , and calculate the first system average SOC based on the obtained first SOC data set:

[0086] .

[0087] The data is obtained through the control unit of each battery pack, and the data of each battery pack is obtained through the control unit of the energy storage system for subsequent retrieval and use.

[0088] S3: Determine whether the absolute difference between the first SOC of the plurality of battery packs and the first system average SOC is greater than a first preset threshold;

[0089] In this embodiment, the first preset threshold is obtained by:

[0090] Acquire third SOCs of the plurality of battery packs at a plurality of consecutive moments, obtaining a third SOC data set consisting of the third SOCs of the plurality of battery packs;

[0091] Obtaining the first preset threshold based on the third SOC data set;

[0092] Specifically, due to the long-term use of battery packs, their own performance will vary. Therefore, the selection of thresholds is related to the historical SOC obtained by the battery pack during long-term use. The SOC conditions at different times can be incorporated into the threshold setting process, making the threshold selection more practical and more accurate. Through the setting of thresholds and the judgment of battery packs, the safety of the battery cluster can be ensured, thereby ensuring the stable operation of the energy storage system.

[0093] Specifically, the first preset threshold is expressed by the following formula (2):

[0094] (2);

[0095] in, is the first preset threshold, is the adjustment coefficient, To adjust the error, For all battery packs M The standard deviation of the SOC values at consecutive moments, It is expressed by formula (4):

[0096] (4);

[0097] in, For all battery packs The standard deviation of the SOC value at each moment is expressed by the following formula:

[0098] (5);

[0099] in, For the The moment The SOC of each battery pack, is the average SOC of the energy storage system at the th moment.

[0100] S4: In response to an absolute difference between the first SOC of the plurality of battery packs and the first system average SOC being greater than a first preset threshold, the battery pack that meets the condition is recorded as a first target battery pack, and all the first target battery packs constitute a first target battery pack set;

[0101] Specifically, the first SOC values of the battery packs in the energy storage system are used to screen battery packs that require detailed adjustment. These selected battery packs are recorded as first target battery packs. In this implementation, it is assumed that the selected battery packs that meet the S4 restriction conditions are: battery pack 1, battery cluster 2, battery cluster 4, battery pack 6, battery pack 8, battery pack 10, battery pack 13, and battery pack 16 (this is only used as an example; in practice, there are many different combinations). The screened battery packs are renumbered: first target battery pack, second target battery pack 2, ..., second target battery pack 8.

[0102] S5: performing a second SOC balancing on all first target battery packs in the first target battery pack set using a second balancing strategy;

[0103] Specifically, after screening out the first target battery group 1, the second target battery group 2, ..., the second target battery group 8, the SOC balancing of the battery groups in the first target battery set is performed according to the second balancing strategy. The specific process is as follows (the following only takes the adjustment of the first target battery group as an example. The adjustment process of other first target battery groups is basically the same and will not be repeated here):

[0104] S51: Divide the first target battery group 1 into a high SOC group, a medium-high SOC group, a medium-low SOC group, and a low SOC group according to the SOC values of the battery cells;

[0105] Among them, the battery cell SOC data of the first battery target battery group 1 is: 、 、…… .

[0106] S52: Transfer energy from the battery cells corresponding to the high SOC set to the battery cells corresponding to the low SOC set, and transfer energy from the battery cells corresponding to the medium-high SOC set to the battery cells corresponding to the medium-low SOC set, until the SOCs of the two battery cells in the first target battery group from which energy is being transferred are equal.

[0107] Specifically, the second balancing strategy is used to monitor the SOC differences between battery cells in real time, transfer the energy of high-SOC battery cells to low-SOC battery cells, and transfer the energy of medium-high SOC battery cells to medium-low SOC battery cells, until the SOC of all battery cells reaches the set balancing level. This embodiment ensures that each battery pack can reach its maximum storage capacity by precisely regulating the single cells, thereby improving the energy utilization of the entire battery pack, improving charging efficiency, reducing the risk of thermal runaway, and further extending battery life.

[0108] S6: updating the SOCs of the plurality of battery packs to obtain a second SOC data set consisting of second SOCs of the plurality of battery packs;

[0109] After the first and second SOC equalizations are completed, the SOC data of each battery pack is reacquired, specifically including the second SOC data set consisting of the second SOCs of battery packs 1-16: 、 、……、 , and the second system average SOC is calculated based on the obtained second SOC data set:

[0110] .

[0111] S7: Determine whether the absolute difference between the second SOC of the plurality of battery packs and the second system average SOC is greater than a second preset threshold;

[0112] Specifically, the second preset threshold is obtained in the following manner:

[0113] Acquire third SOCs of the plurality of battery packs at a plurality of consecutive moments, obtaining a third SOC data set consisting of the third SOCs of the plurality of battery packs;

[0114] Based on the third SOC data set, obtaining two preset thresholds;

[0115] As described in step S3 above, the second preset threshold is expressed as follows (3):

[0116] (3).

[0117] S8: In response to an absolute difference between the second SOC of the plurality of battery packs and the second system average SOC being greater than a second preset threshold, the battery pack meeting this condition is recorded as a second target battery pack, and all the second target battery packs constitute a second target battery pack set;

[0118] Specifically, the second SOC values of the battery packs in the energy storage system are used to screen battery packs that require readjustment. These selected battery packs are recorded as second target battery packs. In this implementation, it is assumed that the selected battery packs that meet the conditions of S7 are: battery pack 1, battery cluster 5, battery pack 9, battery pack 10, battery pack 13, and battery pack 16 (this is only used as an example; in practice, many different combinations exist). The selected battery packs are renumbered: second target battery pack 1, second target battery pack 2, ..., second target battery pack 6.

[0119] S9: Perform a third SOC balancing on all second target battery groups in the second target battery set using a third balancing strategy.

[0120] Specifically, step S9 includes:

[0121] S91: Transferring energy from the second target battery pack corresponding to the maximum SOC in the set of second target battery packs to the second target battery pack corresponding to the minimum SOC until the SOCs of the two second target battery packs being transferred are equal;

[0122] S92: Repeat step S91 until energy transfer is completed between all second target battery groups.

[0123] Specifically, during the charge and discharge process of the battery pack, the SOC difference between the battery pack and the average SOC of the second system is monitored in real time based on the second preset SOC threshold value, and the second target battery pack to be balanced is determined. Then, the SOC values of the battery cells in each second target battery pack are compared through the third balancing strategy, and the energy of the high SOC battery cell is transferred to the low SOC battery cell until the SOC in the second target battery pack reaches the set balancing level, thereby improving the power supply efficiency and power supply stability of the single battery pack and extending the life of the single battery pack to ensure that the entire energy storage system operates in the best working state.

[0124] Compared with the existing technology, the present invention has the following beneficial effects:

[0125] (1) Three balancing control strategies are set up. The first balancing strategy performs inter-group SOC balancing on all battery groups, and then judges the battery groups after the first SOC balancing to screen out the first target battery group set that needs to be balanced. The second balancing strategy performs intra-group SOC balancing on each battery group in the first target battery group set, and then judges the battery groups after the second SOC balancing to screen out the second target battery group set that needs to be balanced. The third balancing strategy performs inter-group SOC balancing on multiple battery groups in the second target battery group set. Through the three SOC balancing of the present invention (two inter-group SOC balancing and one intra-group SOC balancing), the SOC of the battery of the energy storage system can be gradually adjusted, so that the system can quickly and efficiently achieve SOC balancing to ensure that the system battery always works in the best state, thereby reducing damage to the battery and extending the battery life.

[0126] (2) The first balancing strategy is used to achieve SOC balancing among all battery packs, that is, rough balancing adjustment among battery packs. It does not require any data judgment or acquisition operation. As long as the energy storage system is connected, the balancing operation begins. The first balancing control strategy uses a weighted coefficient method to distribute the charge and discharge power of each battery pack so that the SOC of all battery packs is roughly consistent with its target SOC, thereby achieving a rough balance of SOC among battery packs, basically achieving the optimal state of the system, and helping to improve the charge and discharge efficiency;

[0127] (3) The second balancing strategy is used to achieve SOC balance within each battery pack of the first target battery pack. The balancing strategy dynamically adjusts the charge and discharge power of each battery cell in high, medium-high, medium-low and low segments based on the SOC of the battery cell of the battery pack, so that the power of the regulated battery cell remains roughly consistent, achieving SOC balance within the battery cluster, avoiding overcharging or undercharging of the battery cell, helping to improve charging and discharging efficiency, reduce the risk of thermal runaway, and further extend the life of the battery pack; at the same time, balancing the single cells can more effectively utilize the energy of the battery cluster, ensuring that each battery pack can reach its maximum storage capacity, thereby improving the energy utilization rate of the entire energy storage system;

[0128] (4) The third balancing strategy is used to achieve SOC balance between battery groups in the second target battery group, which can achieve SOC balance between battery groups; adjust the SOC between each battery cluster of the energy storage system, that is, finely adjust the SOC of the energy storage system. This strategy dynamically adjusts the charge and discharge power of each target battery cluster based on the second target battery group SOC. The battery group that does not need to be adjusted has reached the optimal state after two SOC adjustments. This adjustment can enable the battery group that needs to be adjusted to reach the optimal state quickly, thereby ensuring that multiple battery clusters of the energy storage system can be used in the best way, and the battery is not easily damaged, thereby improving the life of the system battery cluster; the SOC of multiple battery clusters all reach their respective target SOC, which further maximizes the system charge and discharge power, maximizes the utilization of electrical energy, reduces energy damage, and saves energy.

[0129] Example 2

[0130] Reference Figure 1 This embodiment discloses an SOC balancing device 20 for an energy storage system, comprising:

[0131] A first balancing module 201 is configured to perform a first SOC balancing on the multiple battery packs of the energy storage system using a first balancing strategy;

[0132] The data acquisition module 202 is configured to acquire the first SOCs of the plurality of battery packs at the current moment after the first SOC balancing is completed, thereby obtaining a first SOC data set consisting of the first SOCs of the plurality of battery packs;

[0133] A first determination module 203 is configured to determine whether an absolute difference between a first SOC of the plurality of battery packs and a first system average SOC is greater than a first preset threshold;

[0134] A first processing module 204 is configured to, in response to an absolute difference between a first SOC of a plurality of battery packs and a first system average SOC being greater than a first preset threshold, record the battery pack that meets the condition as a first target battery pack, and all the first target battery packs constitute a first target battery pack set;

[0135] A second balancing module 205 is configured to perform a second SOC balancing on all first target battery packs in the first target battery pack set using a second balancing strategy;

[0136] a data updating module 206 for updating the SOCs of the plurality of battery packs and obtaining a second SOC data set consisting of second SOCs of the plurality of battery packs;

[0137] A second determination module 207 is configured to determine whether an absolute difference between a second SOC of the plurality of battery packs and a second system average SOC is greater than a second preset threshold;

[0138] A second processing module 208 is configured to, in response to an absolute difference between a second SOC of the plurality of battery packs and a second system average SOC being greater than a second preset threshold, record the battery pack that meets the condition as a second target battery pack, and all the second target battery packs constitute a second target battery pack set;

[0139] The third balancing module 209 is configured to perform a third SOC balancing on all second target battery groups in the second target battery set by adopting a third balancing strategy.

[0140] The system provided in the embodiments of the present application can implement the above method, and the system can be implemented by software, hardware, or a combination of software and hardware. For example, the system may include integrated or separate functional modules or units to perform the corresponding steps in each of the above methods. In some implementations of the embodiments of the present application, the system provided in the embodiments of the present application is based on the same inventive concept as the method provided in the previous embodiments of the present application and has the same beneficial effects. No further details will be given here.

[0141] Example 3

[0142] Please refer to Figure 3 , which shows a schematic diagram of an electronic device provided by some embodiments of the present application. Figure 3 As shown, the electronic device 30 includes: a processor 300, a memory 301, a bus 302 and a communication interface 303, and the processor 300, the communication interface 303 and the memory 301 are connected via the bus 302; the memory 301 stores a computer program that can be run on the processor 300, and the processor 300 executes the aforementioned method of this application when running the computer program.

[0143] Memory 301 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device. Communication between the system network element and at least one other network element is achieved through at least one communication interface 303 (which may be wired or wireless), and may utilize the Internet, a wide area network, a local area network, a metropolitan area network, or the like.

[0144] The bus 302 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory 301 is used to store programs. The processor 300 executes the programs upon receiving execution instructions. The methods disclosed in any of the aforementioned embodiments of the present application may be applied to or implemented by the processor 300.

[0145] The processor 300 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor 300 or by software instructions. The above processor 300 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of this application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory 301 , and the processor 300 reads the information in the memory 301 and completes the steps of the above method in combination with its hardware.

[0146] The electronic device provided in the embodiments of the present application and the method provided in the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, operated or implemented by them.

[0147] It should be noted that the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the systems, methods and computer program products according to 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 a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, 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 block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0148] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0149] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, 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 communication interface, the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0150] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0151] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0152] If the functions are implemented in the form of software functional units 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 the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a 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. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0153] Finally, it should be noted that the above embodiments 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, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and description of the present application.

Claims

1. A SOC balancing method for an energy storage system, characterized in that: The steps include: S1: performing a first SOC balancing on multiple battery packs of the energy storage system using a first balancing strategy; S2: After the first SOC balancing is completed, the first SOCs of the multiple battery packs at the current moment are obtained to obtain a first SOC data set consisting of the first SOCs of the multiple battery packs; S3: Determine whether the absolute difference between the first SOC of the plurality of battery packs and the first system average SOC is greater than a first preset threshold; S4: In response to an absolute difference between the first SOCs of the plurality of battery groups and the first system average SOC being greater than a first preset threshold, the battery groups that satisfy the condition that the absolute difference between the first SOCs of the plurality of battery groups and the first system average SOC is greater than the first preset threshold are marked as first target battery groups, and all first target battery groups constitute a first target battery group set; S5: performing a second SOC balancing on all first target battery packs in the first target battery pack set using a second balancing strategy; S6: updating the SOCs of the plurality of battery packs to obtain a second SOC data set consisting of second SOCs of the plurality of battery packs; S7: Determine whether the absolute difference between the second SOC of the plurality of battery packs and the second system average SOC is greater than a second preset threshold; S8: In response to an absolute difference between the second SOCs of the plurality of battery groups and the second system average SOC being greater than a second preset threshold, the battery groups that satisfy the condition that the absolute difference between the second SOCs of the plurality of battery groups and the second system average SOC is greater than the second preset threshold are recorded as second target battery groups, and all second target battery groups constitute a second target battery group set; S9: performing a third SOC balancing on all second target battery packs in the second target battery pack set using a third balancing strategy; Step S1 includes: S11: Based on the total dispatch power of the energy storage system and the weight of each battery group, the target allocation power of each battery group is obtained; S12: Allocating power to each battery pack based on the target allocated power of each battery pack to achieve a first SOC balance among the multiple battery packs; Step S5 includes: S51: Divide each first target battery group in the first target battery group set into a high SOC set, a medium-high SOC set, a medium-low SOC set, and a low SOC set according to the SOC values of the battery cells; S52: Transferring energy from the battery cells corresponding to the high SOC set to the battery cells corresponding to the low SOC set, and transferring energy from the battery cells corresponding to the medium-high SOC set to the battery cells corresponding to the medium-low SOC set, until the SOCs of the two battery cells being transferred in the first target battery group are equal; Step S9 includes: S91: Transferring energy from the second target battery pack corresponding to the maximum SOC in the second target battery pack set to the second target battery pack corresponding to the minimum SOC until the SOCs of the two second target battery packs being transferred are equal; S92: Repeat step S91 until energy transfer is completed between all second target battery groups; The target distribution power of each battery pack is expressed by the following formula: （1）； For the The target power distribution of each battery pack is is the total dispatching power of the energy storage system, is the total number of battery packs in the energy storage system, For the The weight of the battery pack, With the The first system average SOC is the average of all first SOCs in the first SOC data set; the second system average SOC is the average of all second SOCs in the second SOC data set.

2. The method according to claim 1, characterized in that When the energy storage system is in the charging state, the weight of each battery group ; When the energy storage system is in the discharge state, the weight of each battery group = .

3. The method according to claim 2, characterized in that The first preset threshold and the second preset threshold are obtained in the following manner: Acquire third SOCs of the plurality of battery packs at a plurality of consecutive moments, obtaining a third SOC data set consisting of the third SOCs of the plurality of battery packs; Based on the third SOC data set, obtaining the first preset threshold and the second preset threshold; The second preset threshold is smaller than the first preset threshold.

4. The method according to claim 3, characterized in that The first preset threshold and the second preset threshold are respectively expressed by the following formulas (2) and (3): （2）； （3）； in, is the first preset threshold, is the second preset threshold, is the adjustment coefficient, To adjust the error, For all battery packs M The standard deviation of the SOC values at consecutive moments, It is expressed by formula (4): （4）； in, For all battery packs The standard deviation of the SOC value at each moment is expressed by the following formula: （5）； in, For the The moment The SOC of each battery pack, For the The average SOC of the energy storage system at a certain moment.

5. The method according to claim 4, characterized in that The adjustment error and the adjustment coefficient are both related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the energy storage system.

6. A SOC balancing device for an energy storage system, characterized in that: include: A first balancing module, configured to perform a first SOC balancing on the multiple battery packs of the energy storage system using a first balancing strategy; A data acquisition module is configured to acquire the first SOCs of the plurality of battery packs at the current moment after the first SOC balancing is completed, thereby obtaining a first SOC data set consisting of the first SOCs of the plurality of battery packs; a first determination module, configured to determine whether an absolute difference between a first SOC of the plurality of battery packs and a first system average SOC is greater than a first preset threshold; a first processing module, configured to, in response to an absolute difference between the first SOCs of the plurality of battery groups and a first system average SOC being greater than a first preset threshold, record the battery groups that satisfy the condition that the absolute difference between the first SOCs of the plurality of battery groups and the first system average SOC is greater than the first preset threshold as first target battery groups, and all first target battery groups constitute a first target battery group set; A second balancing module, configured to perform a second SOC balancing on all first target battery packs in the first target battery pack set by adopting a second balancing strategy; a data updating module, configured to update the SOCs of the plurality of battery packs and obtain a second SOC data set consisting of second SOCs of the plurality of battery packs; a second determination module, configured to determine whether an absolute difference between a second SOC of the plurality of battery packs and a second system average SOC is greater than a second preset threshold; a second processing module, configured to, in response to an absolute difference between the second SOC of the plurality of battery groups and a second system average SOC being greater than a second preset threshold, record the battery groups that satisfy the condition that the absolute difference between the second SOC of the plurality of battery groups and the second system average SOC is greater than the second preset threshold as second target battery groups, and all the second target battery groups constitute a second target battery group set; A third balancing module, configured to perform a third SOC balancing on all second target battery packs in the second target battery pack set by adopting a third balancing strategy; Performing a first SOC balancing on multiple battery packs of the energy storage system using a first balancing strategy includes: Based on the total dispatch power of the energy storage system and the weight of each battery group, the target allocation power of each battery group is obtained; Allocate power to each battery pack based on its target power allocation to achieve first SOC balancing among the multiple battery packs; Performing a second SOC balancing on all first target battery packs in the first target battery pack set using a second balancing strategy, including: According to each first target battery group in the first target battery group set, divide it into a high SOC set, a medium-high SOC set, a medium-low SOC set and a low SOC set according to the SOC value of the battery cells; Transferring energy from the battery cells corresponding to the high SOC set to the battery cells corresponding to the low SOC set, and transferring energy from the battery cells corresponding to the medium-high SOC set to the battery cells corresponding to the medium-low SOC set, until the SOCs of the two battery cells being transferred in the first target battery group are equal; Performing a third SOC balancing on all second target battery packs in the second target battery pack set using a third balancing strategy, including: Transferring energy from the second target battery pack corresponding to the maximum SOC to the second target battery pack corresponding to the minimum SOC in the second target battery pack set until the SOCs of the two second target battery packs being transferred are equal; Repeat the above steps until energy transfer is completed between all second target battery groups; The target distribution power of each battery pack is expressed by the following formula: （1）； For the The target power distribution of each battery pack is is the total dispatching power of the energy storage system, is the total number of battery packs in the energy storage system, For the The weight of the battery pack, With the The first system average SOC is the average of all first SOCs in the first SOC data set; the second system average SOC is the average of all second SOCs in the second SOC data set.

7. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is configured to read the executable instructions from the memory and execute the executable instructions to implement the method according to any one of claims 1 to 5.

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