Energy storage system and capacity equalization method and device thereof

Abstract

The present disclosure provides a kind of energy storage system and its capacity equalization method, device, it is related to energy storage technical field.Energy storage system includes at least one battery cluster, battery cluster includes power module and multiple battery modules, the method includes: obtaining the residual capacity SOC of each battery module in target battery cluster;Wherein, target battery cluster is one in at least one battery cluster;If the SOC of multiple battery modules in target battery cluster does not satisfy preset equalization condition, then according to the SOC of multiple battery modules, determine the battery module to be equalized from multiple battery modules;Control power module switches to the battery module to be equalized and carries out power supply, to make the SOC of multiple battery modules in target battery cluster satisfy preset equalization condition.The present disclosure can realize the SOC equalization of multiple battery modules in target battery cluster, reduce energy loss, save energy, guarantee power module reliability, improve the communication stability of overall energy storage system.

Description

Technical Field

[0001] This disclosure relates to the field of energy storage technology, and in particular to an energy storage system, a capacity balancing method for an energy storage system, and a capacity balancing device for an energy storage system. Background Technology

[0002] Energy storage systems generally consist of battery modules (or battery clusters) composed of a certain number of battery cells connected in series or parallel, and battery systems composed of multiple battery modules connected in series. Within the same battery cluster, the inconsistency of the remaining capacity (State of Charge, SOC) of each battery module during use can lead to uneven distribution due to factors such as temperature and the individual cells themselves.

[0003] To address the issue of unbalanced State of Charge (SOC) among battery modules within a battery cluster, related technologies typically employ passive discharge of high-energy battery modules through resistors to ensure that the energy levels of the high-energy modules are consistent with those of the low-energy modules.

[0004] However, the aforementioned SOC balancing method dissipates excess energy as heat, resulting in energy waste and safety hazards. Furthermore, in order to maintain a suitable operating temperature for the battery cells, cooling methods such as air conditioning are required, further wasting energy.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] This disclosure provides an energy storage system and its equalization method and apparatus, which at least to some extent overcomes the problems of energy waste and safety hazards caused by the capacity equalization methods of energy storage systems provided in related technologies.

[0007] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part by practice of this disclosure.

[0008] According to one aspect of this disclosure, a capacity balancing method for an energy storage system is provided. The energy storage system includes at least one battery cluster, each battery cluster including a power-consuming module and multiple battery modules. The method includes: obtaining the remaining state of charge (SOC) of each battery module in a target battery cluster; wherein the target battery cluster is one of the at least one battery cluster; if the SOC of the multiple battery modules in the target battery cluster does not meet a preset balancing condition, determining a battery module to be balanced from the multiple battery modules based on the SOC of the multiple battery modules; and controlling the power-consuming module to switch to the battery module to be balanced for power supply, so that the SOC of the multiple battery modules in the target battery cluster meets the preset balancing condition.

[0009] In this embodiment, the SOC of the target battery cluster is determined based on the SOC of each battery module in the target battery cluster to determine whether the SOC of the battery cluster meets the preset balancing conditions. If the SOC does not meet the preset balancing conditions, the battery module to be balanced is determined based on the SOC of multiple battery modules, and then the battery module to be balanced is controlled to supply power to the power consumption module. On the one hand, it can achieve SOC balancing of multiple battery modules in the target battery cluster without the need for other cooling methods, make reasonable use of the excess energy of the battery module to be balanced, reduce energy loss, reduce the load on environmental control systems such as air conditioning, save energy, and improve safety. On the other hand, since the power consumption module in the energy storage system changes from conventional single-path power supply to multi-path power supply, the reliability of the power consumption module is guaranteed, thereby improving the overall communication stability of the energy storage system.

[0010] In one embodiment of this disclosure, determining the battery module to be balanced from the plurality of battery modules based on their SOC includes: determining the battery module with the highest SOC among the plurality of battery modules as the battery module to be balanced.

[0011] In this embodiment, the battery module with the highest SOC among multiple battery modules is identified as the battery module to be balanced. The method of identifying the battery module to be balanced is simple and easy to operate, which greatly shortens the capacity balancing time of the energy storage system and improves the balancing efficiency.

[0012] In one embodiment of this disclosure, determining the battery module to be balanced from the plurality of battery modules based on their SOC includes: calculating the average SOC of the plurality of battery modules, and determining an upper limit value of the SOC of each battery module based on the average SOC of the plurality of battery modules; and determining the battery module to be balanced based on the SOC of the plurality of battery modules and the upper limit value of the SOC.

[0013] In this embodiment of the disclosure, the average SOC of multiple battery modules is calculated, and the upper limit of SOC is determined based on the average SOC. Thus, the battery modules to be balanced are determined based on the SOC of multiple battery modules and the upper limit of SOC. This effectively identifies the factors in the battery cluster that have a significant impact on SOC imbalance, which is conducive to quickly achieving capacity balancing of the energy storage system and improving balancing efficiency.

[0014] In one embodiment of this disclosure, determining the battery module to be balanced based on the SOC of the plurality of battery modules and the upper limit of the SOC includes: selecting target battery modules from the plurality of battery modules that have an SOC greater than the upper limit of the SOC; if the number of target battery modules is a single one, then the target battery module is determined as the battery module to be balanced.

[0015] In this embodiment of the disclosure, when the number of target battery modules is a single one, it indicates that the SOC of the target battery module differs greatly from the SOC of the remaining battery modules among multiple battery modules. By controlling the target battery module, it is beneficial to quickly achieve capacity balancing of the energy storage system and improve balancing efficiency.

[0016] In one embodiment of this disclosure, after selecting target battery modules from the plurality of battery modules that have a SOC greater than the upper limit value, the method further includes: if there are multiple target battery modules, calculating the difference between the SOC of any two target battery modules; if there are at least two target battery modules whose SOC difference is less than or equal to a preset difference threshold, then determining at least two target battery modules as the battery modules to be balanced, so as to synchronously supply power to the power-consuming module.

[0017] In this embodiment of the disclosure, when the battery module to be balanced includes at least two target battery modules and the SOC of at least two target battery modules is close, the capacity balancing time of the energy storage system is further shortened and the balancing efficiency is improved by simultaneously switching on and off the at least two target battery modules and simultaneously supplying power to the power consumption module.

[0018] In one embodiment of this disclosure, after determining the battery module to be balanced from the plurality of battery modules based on the SOC of the plurality of battery modules, and before controlling the power consumption module to switch to the battery module to be balanced for power supply, the method further includes: performing voltage conversion on the output voltage of the battery module to be balanced so that the converted voltage meets the power supply conditions of the power consumption module.

[0019] In this embodiment, since the output voltage of the battery module to be balanced may not match the input voltage of the power module, voltage conversion is performed on the output voltage of the battery module to be balanced to ensure the stability and safety of the power module.

[0020] In one embodiment of this disclosure, after controlling the power consumption module to switch to the battery module to be balanced for power supply, the method further includes: if the SOC of the plurality of battery modules in the target battery cluster meets a preset balancing condition, then controlling the power consumption module to switch from the battery module to be balanced to the target power supply module for power supply; wherein, the target power supply module is not one of the plurality of battery modules.

[0021] In this embodiment of the disclosure, during the process of supplying power to the power-consuming module through the battery module to be balanced, the SOC balance of multiple battery modules in the target battery cluster is monitored to avoid the problem of excessive discharge of the battery module to be balanced, which would cause excessive fluctuations in the SOC balance state of the target battery cluster, thereby improving system stability.

[0022] In one embodiment of this disclosure, after controlling the power consumption module to switch to the battery module to be balanced for power supply, the method further includes: continuously performing SOC acquisition processing on the plurality of battery modules to obtain an updated SOC of the plurality of battery modules; if the updated SOC of the plurality of battery modules does not meet the preset balancing condition, then continuing to determine the battery module to be balanced based on the updated SOC to obtain an updated battery module to be balanced; controlling the power consumption module to switch to the updated battery module to be balanced for power supply until the SOC of the plurality of battery modules in the target battery cluster meets the preset balancing condition.

[0023] In the embodiments of this disclosure, by continuously acquiring the SOC of multiple battery modules, it is possible to continuously monitor whether the SOC of multiple battery modules in the target battery cluster is in a balanced state, thereby ensuring the accuracy of capacity balancing of the energy storage system, effectively preventing the battery modules to be balanced from over-discharging, and improving the safety of the energy storage system.

[0024] In one embodiment of this disclosure, the power module includes at least one of a power management system and a high-voltage contactor.

[0025] In this embodiment, on the one hand, the power management system is powered by the battery module to be balanced, thereby ensuring uninterrupted power supply to the power management system and improving the stability and safety of the energy storage system; on the other hand, the high-voltage contactor is powered by the battery module to be balanced, thereby ensuring the high-voltage contactor's continuous power demand during startup and holding states, and improving the stability and safety of the energy storage system.

[0026] In one embodiment of this disclosure, the method further includes: if the difference between the maximum SOC value and the minimum SOC value of the battery modules in the target battery cluster is greater than a preset SOC threshold, or the difference in SOC between any two battery modules in the target battery cluster is greater than the preset SOC threshold, then it is determined that the SOC of the battery modules in the target battery cluster does not meet the preset balancing condition. In this embodiment, by comparing the difference between the maximum and minimum SOC values ​​of the battery modules with a preset SOC threshold, or by comparing the difference in SOC between any two battery modules with a preset SOC threshold, the method determines whether the SOC of the battery modules in the target battery cluster meets the preset balancing condition based on the comparison result, thereby determining the SOC balancing timing of the battery modules in the target battery cluster. This method is simple and highly practical.

[0027] According to another aspect of this disclosure, a capacity balancing device for an energy storage system is also provided. The energy storage system includes at least one battery cluster, the battery cluster including a power-consuming module and multiple battery modules. The device includes: an acquisition module, configured to acquire the State of Charge (SOC) of each battery module in a target battery cluster; wherein the target battery cluster is one of the at least one battery cluster; a determination module, configured to determine a battery module to be balanced from the multiple battery modules based on the SOC of the multiple battery modules if the SOC of the multiple battery modules in the target battery cluster does not meet a preset balancing condition; and a control module, configured to control the power-consuming module to switch to the battery module to be balanced for power supply, so that the SOC of the multiple battery modules in the target battery cluster meets the preset balancing condition. In this embodiment of the disclosure, combined with the above-mentioned capacity balancing method for energy storage systems, on the one hand, it can achieve SOC balancing of multiple battery modules in the target battery cluster without the need for other cooling methods, make reasonable use of the excess energy of the battery modules to be balanced, reduce energy loss, reduce the load on environmental control systems such as air conditioning, and save energy; on the other hand, since the power consumption modules in the energy storage system are changed from conventional single-path power supply to multi-path power supply, the reliability of the power consumption modules is guaranteed, thereby improving the overall communication stability of the energy storage system.

[0028] In one embodiment of this disclosure, the device further includes a voltage conversion module, which converts the output voltage of the battery module to be balanced so that the converted voltage meets the power supply conditions of the power consumption module. In this embodiment, by providing a voltage conversion module, the output voltage of the battery module to be balanced can be converted into a suitable input voltage for the power consumption module, thereby ensuring the safety of the power consumption module.

[0029] According to another aspect of this disclosure, an energy storage system is also provided, including at least one battery cluster and the aforementioned capacity balancing device for the energy storage system. The battery cluster includes a power consumption module and multiple battery modules. In this embodiment of the disclosure, by incorporating the aforementioned capacity balancing device for the energy storage system, the stability of the energy storage system is improved while the balancing device has better balancing efficiency and reduced energy consumption.

[0030] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0032] Figure 1 This diagram illustrates a flow chart of a capacity balancing method for an energy storage system provided in an embodiment of this disclosure.

[0033] Figure 2 This diagram illustrates a flow chart of another capacity balancing method for an energy storage system provided in an embodiment of this disclosure.

[0034] Figure 3 This diagram illustrates a flowchart of another capacity balancing method for an energy storage system provided in an embodiment of this disclosure.

[0035] Figure 4 This diagram illustrates a method for determining a battery module to be balanced according to an embodiment of the present disclosure.

[0036] Figure 5 This diagram illustrates another method for determining battery modules to be balanced, as provided in an embodiment of this disclosure.

[0037] Figure 6 Show Figure 5 A flowchart illustrating the specific implementation of a method for determining battery modules to be balanced, provided in the document;

[0038] Figure 7 Show Figure 5 The flowchart of another method for determining the battery module to be balanced provided in the article is shown below.

[0039] Figure 8 This diagram illustrates a flow chart of another capacity balancing method for an energy storage system provided in an embodiment of this disclosure.

[0040] Figure 9 This diagram illustrates a specific example flowchart of a capacity balancing method for an energy storage system provided in an embodiment of this disclosure.

[0041] Figure 10 This diagram illustrates the structure of a capacity balancing device for an energy storage system according to an embodiment of the present disclosure.

[0042] Figure 11 This diagram illustrates the structure of an energy storage system provided in an embodiment of the present disclosure. Detailed Implementation

[0043] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0044] The terms "first" and "second" used in this document are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly stated.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] The following disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0047] SOC, or State of Charge, refers to the state of a battery's charge, also known as remaining capacity, and characterizes the battery's ability to continue operating. Typically, SOC is the ratio of the charged capacity to the rated capacity, expressed as a percentage. For a battery or battery module, charging at a certain rate for a certain period yields a charge; the ratio of this charge to the rated capacity is the SOC, which ranges from 0 to 1. When SOC = 0, the battery is fully discharged; when SOC = 1, the battery is fully charged.

[0048] Battery SOC cannot be directly measured. Its value can be evaluated through electrical parameters such as the terminal voltage, charging and discharging current, and internal resistance of the battery or battery module. However, the electrical parameters of the battery or battery module are affected by a variety of uncertain factors such as aging and changes in ambient temperature.

[0049] Depending on the switching and charge transfer methods, battery SOC balancing technology in energy storage systems can generally be divided into energy dissipation balancing and energy non-dissipation balancing. Energy dissipation balancing typically involves dissipating excess energy as heat from high-energy battery modules within the battery cluster using energy-dissipating components such as bypass resistors, thereby ensuring SOC balance. However, this method results in energy waste, and overheating of the battery cluster poses a safety hazard. Energy non-dissipation balancing mainly involves external balancing circuitry and utilizes energy storage components such as inductors to achieve energy transfer between battery modules within the battery cluster. However, this method has a complex structure, which is not conducive to the miniaturization of energy storage systems.

[0050] Therefore, it is necessary to design a capacity balancing method for energy storage systems that can minimize energy loss while ensuring the miniaturization of the energy storage system.

[0051] Based on this, this disclosure provides a capacity balancing method for an energy storage system. The method determines whether the SOC of multiple battery modules in the target battery cluster meets preset balancing conditions based on the SOC of each battery module. If the SOC of multiple battery modules does not meet the preset balancing conditions, the method identifies the battery modules to be balanced based on their SOC, and then controls these modules to supply power to the power-consuming modules. This achieves SOC balancing of multiple battery modules in the target battery cluster without requiring other cooling methods, rationally utilizes the excess energy of the modules to be balanced, reduces energy loss, lowers the load on environmental control systems such as air conditioning, saves energy, and improves safety. Furthermore, since the power-consuming modules in the energy storage system are changed from conventional single-path power supply to multi-path power supply, the reliability of the power-consuming modules is ensured, thereby improving the overall communication stability of the energy storage system.

[0052] It should be noted that, unless otherwise specified, the embodiments of the present invention and the technical features thereof can be combined with each other.

[0053] The following detailed description of this exemplary implementation method is provided in conjunction with the accompanying drawings and embodiments.

[0054] This disclosure provides a capacity balancing method for an energy storage system. This method can be executed by any system with computing power. For example, the capacity balancing method for the energy storage system in this disclosure can be executed by a battery management system.

[0055] Figure 1 A flowchart illustrating a capacity balancing method for an energy storage system provided in an embodiment of this disclosure is shown. Figure 1 As shown in the embodiments of this disclosure, the capacity balancing method of the energy storage system includes at least one battery cluster, the battery cluster includes a power consumption module and multiple battery modules, and the method includes:

[0056] S102. Obtain the remaining capacity (SOC) of each battery module in the target battery cluster, wherein the target battery cluster is one of at least one battery cluster.

[0057] In one embodiment, the energy storage system includes at least one battery cluster and a battery management system (BMS) connected to the at least one battery cluster, wherein when the number of battery clusters is greater than one, the battery clusters are connected in series. Each battery cluster includes at least two battery modules connected in series and / or in parallel, and the performance of the battery modules in the at least one battery cluster is not exactly the same, for example, in terms of operating time, electrical parameters, temperature, etc.

[0058] The battery management system collects performance parameters from each battery module, such as voltage, charging current, discharging current, and temperature, and calculates the state of charge (SOC) of the battery module through fitting. It should be noted that the sampling frequency or period for the battery module performance parameters collected by the battery management system depends on the actual situation, for example, once per minute.

[0059] S104. If the SOC of multiple battery modules in the target battery cluster does not meet the preset equalization conditions, then determine the battery module to be equalized from the multiple battery modules based on the SOC of the multiple battery modules.

[0060] By comparing the State of Charge (SOC) of each battery module in the target battery cluster, it is determined whether the SOC of the battery modules in the target battery cluster meets the preset equalization condition. For example, if the difference between the maximum and minimum SOC of a battery module in the target battery cluster is greater than a preset SOC threshold, or if the difference between the SOCs of any two battery modules in the target battery cluster is greater than the preset SOC threshold, it is determined that the SOC of multiple battery modules in the target battery cluster does not meet the preset equalization condition. The preset SOC threshold can be 5%, 10%, etc., depending on the actual situation. There are various ways to determine whether the SOC of multiple battery modules in the target battery cluster meets the preset equalization condition, which can be determined according to the actual process, and this disclosure does not make specific limitations. This disclosure determines whether the SOC of the battery modules in the target battery cluster meets the preset equalization condition by comparing the difference between the maximum and minimum SOC of a battery module with the preset SOC threshold, or by comparing the difference between the SOCs of any two battery modules with the preset SOC threshold, and then determining the timing of SOC equalization of the battery modules in the target battery cluster based on the comparison result. This method is simple and highly practical.

[0061] The aforementioned preset conditions may include conditions that need to be met when the battery module is in a charging state, or conditions that need to be met when the battery module is in a discharging state.

[0062] The battery modules to be balanced are those that need to undergo SOC balancing. By releasing excess energy, the SOC of each battery module in the battery cluster is brought into a balanced state.

[0063] For example, when the SOC of a battery module in the target battery cluster does not meet the preset balancing condition and the battery module is in a discharging state, it is determined that the SOCs of multiple battery modules in the target battery cluster are unbalanced, and the battery module corresponding to the maximum SOC value is identified as the battery module to be balanced. If the SOC of a battery module in the target battery cluster meets the preset balancing condition and the battery module is in a discharging state, then the other battery modules in the target battery cluster are iterated to see if they meet the preset balancing condition, until all battery modules in the target battery cluster have been judged, and the battery module to be balanced is obtained. The process for the battery module in a charging state is similar to the above process and will not be described in detail here.

[0064] S106. Control the power supply module to switch to the battery module to be balanced for power supply, so that the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions.

[0065] It should be noted that the power module may include at least one of the following: a power management system and a high-voltage contactor. On the one hand, the power management system is powered by the battery module to be balanced, thereby ensuring uninterrupted power supply to the power management system and improving the stability and safety of the energy storage system. On the other hand, the high-voltage contactor is powered by the battery module to be balanced, thereby ensuring the high-voltage contactor's continuous power supply needs during startup and maintenance, and improving the stability and safety of the energy storage system.

[0066] Each battery module in the battery cluster is connected to a switching switch. By controlling the switching switch, when the battery module to be balanced is not in the SOC equalization state, the charging and discharging circuit is cut off and connected to the circuit of the power consumption module in the energy storage system to supply power to the power consumption module. After the battery module to be balanced achieves SOC equalization, the switching switch is controlled to disconnect the battery module to be balanced from the power consumption module and reconnect it to the charging and discharging circuit.

[0067] The capacity balancing method for energy storage systems provided in this disclosure determines whether the SOC of the battery cluster is balanced based on the SOC of each battery module in the battery cluster. In the case of SOC imbalance, the battery modules to be balanced are identified by comparing the relationship between the SOC and preset conditions. Then, the battery modules to be balanced supply power to the power-consuming modules. On the one hand, it can achieve SOC balancing of the battery modules in the battery cluster without the need for other cooling methods, make reasonable use of the excess energy of the battery modules to be balanced, reduce energy loss, reduce the load on environmental control systems such as air conditioning, save energy, and improve safety. On the other hand, since the power-consuming modules in the energy storage system are changed from conventional single-path power supply to multi-path power supply, the reliability of the power-consuming modules is guaranteed, thereby improving the overall communication stability of the energy storage system.

[0068] Figure 2 This diagram illustrates a flow chart of another capacity balancing method for an energy storage system provided in an embodiment of this disclosure. Figure 1 Based on the embodiment, after S106, the method further includes S108 to S112 to continuously determine whether the SOC of multiple battery modules within the target battery cluster meets a preset equalization condition, thereby ensuring SOC equalization of the multiple battery modules within the target battery cluster. In one embodiment, such as Figure 2 As shown, the capacity balancing method for the energy storage system in this embodiment includes steps S102 to S112. Specifically, the method includes:

[0069] S108. Continuously process the SOC acquisition of multiple battery modules to obtain the updated SOC of multiple battery modules;

[0070] S110. If the updated SOC of multiple battery modules does not meet the preset balancing conditions, the battery modules to be balanced are determined based on the updated SOC to obtain the updated battery modules to be balanced.

[0071] S112. Control the power module to switch to the updated battery module to be balanced for power supply until the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions.

[0072] It should be noted that the specific implementation of S102 to S106 in this embodiment is the same as that of S102 to S106 in the previous embodiment, and will not be repeated here.

[0073] In one embodiment, after the control power module switches to the battery module to be balanced for power supply, the SOC of multiple battery modules is continuously monitored. For example, the SOC of multiple battery modules is collected once every preset time (such as 5 minutes, 10 minutes, etc.) to determine whether the updated SOC of multiple battery modules meets the preset balancing conditions. By continuously acquiring the SOC of multiple battery modules, the SOC of multiple battery modules in the target battery cluster is continuously monitored to ensure that the capacity balancing accuracy of the energy storage system is guaranteed, effectively preventing the battery module to be balanced from over-discharging and improving the safety of the energy storage system.

[0074] Figure 3 A flowchart illustrating another capacity balancing method for an energy storage system provided in an embodiment of this disclosure is shown. Figure 1 Based on the embodiment, after S106, the method further includes S114, to control the power-consuming module to switch power supply modes when the SOC of multiple battery modules in the target battery cluster meets a preset balancing condition. In one embodiment, such as Figure 3As shown, the capacity balancing method for an energy storage system provided in this embodiment includes steps S102 to S106 and step S114. Specifically, the method includes:

[0075] If the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions, the control power module switches from the battery modules to be balanced to the target power supply module for power supply; wherein, the target power supply module is not multiple battery modules.

[0076] It should be noted that the implementation of S102 to S106 in this embodiment is the same as the specific implementation of S102 to S106 described above, and will not be repeated here.

[0077] When the State of Charge (SOC) of multiple battery modules in the target battery cluster meets the preset balancing condition, it indicates that the SOC of the multiple battery modules in the target battery cluster is in a balanced state, and the battery module to be balanced is controlled to disconnect from the power supply circuit of the power-consuming module. The target power supply module can be the main power supply module of the power-consuming module, such as the mains power supply module, the backup power supply module, etc.

[0078] This disclosure improves system stability by monitoring the SOC balance of multiple battery modules within a battery cluster during the process of supplying power to the power-consuming module through the battery module to be balanced. This prevents the battery module to be balanced from over-discharging, which could cause excessive fluctuations in the SOC balance of the battery cluster, thus improving system stability.

[0079] Figure 4 This diagram illustrates a flowchart of a method for determining a battery module to be balanced, as provided in an embodiment of this disclosure. Figure 1 Based on the embodiment, step S104, which involves determining the battery module to be balanced from multiple battery modules based on their SOC, is refined to S1041 to determine the battery module to be balanced. For example... Figure 4 As shown, the capacity balancing method for an energy storage system according to an embodiment of this disclosure includes steps S102, S1041, and S106. Specifically, the method includes:

[0080] S1041. The battery module with the highest SOC among multiple battery modules is identified as the battery module to be balanced.

[0081] It should be noted that the implementation methods of S102 and S106 are the same as the specific implementation methods of the aforementioned embodiments, and will not be repeated here.

[0082] In one embodiment, S1041 described above can be implemented in the following way: sorting the SOC of multiple battery modules in the battery cluster according to a preset rule; selecting a preset number of battery modules whose SOC is ranked first or last as battery modules to be balanced, wherein the SOC of the preset number of battery modules ranked first or last is greater than the SOC of the remaining battery modules in the battery cluster.

[0083] The aforementioned preset rules can be sorted from largest to smallest, or sorted from smallest to largest.

[0084] The preset quantity can be a fixed value or a fixed proportion, depending on the actual situation. For example, sort the SOC of multiple battery modules in a battery cluster in ascending order, and select the bottom 5 battery modules as the battery modules to be balanced, or select the bottom 5% of battery modules as the battery modules to be balanced. The filtering method is similar for sorting from largest to smallest, and will not be repeated here.

[0085] For example, the preset quantity can be one or more, that is, the battery modules to be balanced can include one or more battery modules. When the battery modules to be balanced include multiple battery modules, the balancing operation can be performed on each battery module separately.

[0086] The capacity balancing method for energy storage systems provided in this disclosure identifies the battery module with the highest SOC among multiple battery modules as the battery module to be balanced. The method for determining the battery module to be balanced is simple and easy to operate, which greatly shortens the capacity balancing time of the energy storage system and improves the balancing efficiency.

[0087] Figure 5 This diagram illustrates a flowchart of another method for determining battery modules to be balanced, provided by an embodiment of this disclosure. Figure 1 Based on the embodiment, step S104, determining the battery module to be balanced from the multiple battery modules according to their SOC, is refined into S1042-S1043 to disclose a specific scheme for determining the battery module to be balanced. For example... Figure 5 As shown, the capacity balancing method for an energy storage system according to an embodiment of this disclosure includes steps S102, S1042-S1044, and S106. Specifically, the method includes:

[0088] S1042. Calculate the average SOC of multiple battery modules, and determine the upper limit of SOC of each battery module based on the average SOC of multiple battery modules.

[0089] S1044. Determine the battery modules to be balanced based on the SOC and upper limit of the SOC of multiple battery modules.

[0090] It should be noted that the implementation methods of S102 and S106 are the same as the specific implementation methods of the aforementioned embodiments, and will not be repeated here.

[0091] In one embodiment, the average SOC of the battery modules is the ratio of the sum of the SOCs of the individual battery modules to the number of battery modules. The upper limit of the SOC is the sum of the average SOC of the battery modules and a preset SOC offset. The preset SOC offset can be pre-configured in the battery control system or defined by the user according to the usage of the battery modules. The preset SOC offset can control the number of battery modules in the battery module to be balanced, so as to filter out battery modules that deviate from the average SOC.

[0092] This disclosure calculates the average SOC of multiple battery modules and determines the upper limit of SOC based on the average SOC. Thus, it identifies the battery modules to be balanced based on the SOC of multiple battery modules and the upper limit of SOC, effectively identifying the factors that have a significant impact on SOC imbalance in the battery cluster. This facilitates the rapid realization of capacity balancing in the energy storage system and improves balancing efficiency.

[0093] Figure 6 Show Figure 5 The flowchart illustrates the specific implementation of a method for determining battery modules to be balanced, as provided in the document. Figure 5 Based on the embodiment, step S1044 includes S1045 to S1046, to determine which individual battery module supplies power to the power-consuming module. For example... Figure 6 As shown, the capacity balancing method for an energy storage system according to an embodiment of this disclosure includes steps S102, S1042-S1046, and S106. Specifically, the method includes:

[0094] S1045. Select target battery modules from multiple battery modules that have a SOC upper limit.

[0095] S1046. If the number of target battery modules is a single one, then the target battery module is determined as the battery module to be balanced.

[0096] It should be noted that the specific implementation methods of S102, S1042, and S106 in this embodiment are the same as those in the above embodiments, and will not be repeated here.

[0097] Determine whether the SOC of each battery module is greater than the upper limit of SOC. If it is, then the battery module with the upper limit of SOC is selected as the target battery module.

[0098] When the number of target battery modules is a single one, it indicates that among multiple battery modules, only the target battery module has a large difference in SOC compared to the other battery modules. The target battery module is then identified as the battery module to be balanced. By controlling the target battery module, it is beneficial to quickly achieve capacity balancing of the energy storage system and improve balancing efficiency.

[0099] Figure 7 Show Figure 5The flowchart illustrates a specific implementation method for determining another battery module to be balanced, as provided in the document. Figure 5 Based on the embodiment, step S1042 includes S1045, S1047-S1048, to determine that multiple battery modules simultaneously supply power to the power-consuming module. For example... Figure 6 As shown, the capacity balancing method for an energy storage system according to an embodiment of this disclosure includes steps S102, S1042, S1045, S1047-S1048, and S106. Specifically, the method includes:

[0100] S1047. If there are multiple target battery modules, calculate the difference in SOC between any two target battery modules.

[0101] S1048. If the difference between the SOC of at least two target battery modules is less than or equal to a preset difference threshold, then at least two target battery modules are identified as battery modules to be balanced, so as to synchronously supply power to the power-consuming module.

[0102] It should be noted that the implementation methods of S102, S1042, S1045, and S106 in this embodiment are the same as the specific implementation methods of the aforementioned embodiments, and will not be repeated here.

[0103] In one embodiment, when the number of battery modules in the battery modules to be balanced includes multiple modules, the difference between the SOC of any two battery modules to be balanced is calculated; if the difference between the SOC of at least two battery modules to be balanced is less than or equal to a preset difference threshold, then at least two battery modules are used as synchronous balancing battery modules to supply power to the power consumption module.

[0104] The aforementioned preset difference threshold is used to determine whether the State of Charge (SOC) of at least two battery modules in the battery modules to be balanced is close. Generally, when the difference in SOC between two battery modules equals the preset difference threshold, the smaller the preset difference threshold, the smaller the SOC difference between the two battery modules; the larger the preset difference threshold, the larger the SOC difference between the two battery modules. The preset difference threshold can be pre-configured in the battery management system to facilitate the determination of synchronously balanced battery modules based on the preset difference threshold.

[0105] At least two battery modules can be connected in series via a switch to supply power to the power-consuming module.

[0106] The capacity balancing method for energy storage systems provided in this disclosure, when the battery modules to be balanced include at least two target battery modules and the SOC of at least two target battery modules are close, further shortens the capacity balancing time of the energy storage system and improves the balancing efficiency by simultaneously switching on and off at least two target battery modules and simultaneously supplying power to the power-consuming module.

[0107] Figure 8 This diagram illustrates a flow chart of another capacity balancing method for an energy storage system provided in an embodiment of this disclosure. Figure 1 Based on the previous embodiment, before step S106 switches the power supply module to the battery module to be balanced for power supply, after determining the battery module to be balanced from multiple battery modules based on the SOC of multiple battery modules in step 104, step S105 is added to adjust the output voltage value of the battery module to be balanced. Figure 8 As shown, the capacity balancing method for the energy storage system in this embodiment includes steps S102 to S106. Specifically, the method includes:

[0108] S105. Perform voltage conversion on the output voltage of the battery module to be balanced so that the converted voltage meets the power supply requirements of the power module.

[0109] It should be noted that the implementation methods of S102 to S106 are the same as the specific implementation methods of the aforementioned embodiments, and will not be repeated here.

[0110] When at least two target battery modules in the battery module to be balanced are connected in series to supply power to the power-consuming module, or when one target battery module in the battery module to be balanced directly supplies power to the power-consuming module, there may be a mismatch between the output voltage of the aforementioned at least two target battery modules or the aforementioned target battery module and the input voltage of the power-consuming module. This could potentially burn out the power-consuming module and pose a safety hazard. Therefore, a voltage conversion module is installed between the battery module to be balanced and the power-consuming module to convert the output voltage of the battery module to be balanced, so that the converted voltage matches the input voltage of the power-consuming module. The aforementioned power supply conditions refer to the range of values ​​for the input voltage of the power-consuming module, and the power supply conditions can be pre-configured within the battery management system.

[0111] The capacity balancing method for energy storage systems provided in this disclosure addresses the issue that the output voltage of the battery module to be balanced may not match the input voltage of the power-consuming module. Therefore, by converting the output voltage of the battery module to be balanced, the stability and safety of the power-consuming module are ensured.

[0112] To facilitate understanding of the embodiments of this disclosure, specific examples are described below.

[0113] like Figure 9 As shown, the capacity balancing method for the energy storage system provided in this example includes the following steps:

[0114] S902: The battery management system collects data and calculates the SOC of multiple battery modules in the target battery cluster.

[0115] S904. Determine whether the SOC of multiple battery modules in the target battery cluster meets the preset equalization condition; if it does, execute S902; if it does not, execute S906.

[0116] S906. Sort the SOC of multiple battery modules in the target battery cluster to determine the battery modules to be balanced.

[0117] S908: Cut out the battery module to be balanced and connect the circuit to supply power to the battery management system.

[0118] S910. Determine whether the SOC of multiple battery modules in the target battery cluster meets the preset equalization condition. If it does, execute S912; otherwise, execute S906.

[0119] S912, disconnect the battery module to be balanced, and switch the battery management system to normal power supply.

[0120] It should be noted that for the battery modules to be balanced, the upper limit of the SOC can also be determined by the average value of the SOC of the battery modules, and then determined according to the upper limit of the SOC. When the battery modules to be balanced include multiple battery modules, battery modules with similar SOC can be selected to supply power to the power consumption module simultaneously.

[0121] Based on the same inventive concept, this disclosure also provides a capacity balancing device for an energy storage system, as described in the following embodiments. Since the principle by which this device solves the problem is similar to that of the method embodiments described above, the implementation of this device embodiment can refer to the implementation of the method embodiments described above, and repeated details will not be elaborated further.

[0122] like Figure 10 As shown in the present disclosure, an embodiment of the energy storage system provides a capacity balancing device for an energy storage system. The energy storage system includes at least one battery cluster, and the battery cluster includes a power consumption module and multiple battery modules. The device includes an acquisition module 1001, a determination module 1002, and a control module 1003.

[0123] The module comprises: an acquisition module 1001, used to acquire the SOC of each battery module in the target battery cluster; wherein the target battery cluster is one of at least one battery cluster; a determination module 1002, used to determine the battery module to be balanced from the multiple battery modules based on the SOC of the multiple battery modules if the SOC of multiple battery modules in the target battery cluster does not meet the preset balancing conditions; and a control module 1003, used to control the power consumption module to switch to the battery module to be balanced for power supply, so that the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions.

[0124] In one embodiment, the determining module 1002 is used to determine the battery module with the largest SOC among multiple battery modules as the battery module to be balanced.

[0125] In one embodiment, the determining module 1002 is used to calculate the average SOC of multiple battery modules and determine the average SOC of multiple battery modules as the upper limit of the SOC of each battery module; and determine the battery module to be balanced based on the SOC of multiple battery modules and the upper limit of SOC.

[0126] In one embodiment, the determining module 1002 is further configured to filter target battery modules from multiple battery modules that have a SOC upper limit; if the number of target battery modules is a single one, then the target battery module is determined as the battery module to be balanced.

[0127] In one embodiment, the determining module 1002 is further configured to: if there are multiple target battery modules, calculate the difference between the SOC of any two target battery modules; if the difference between the SOC of at least two target battery modules is less than or equal to a preset difference threshold, determine at least two target battery modules as battery modules to be balanced, so as to synchronously supply power to the power-consuming module.

[0128] In one embodiment, the device further includes a voltage conversion module (not shown in the figures) for converting the output voltage of the battery module to be balanced so that the converted voltage meets the power supply requirements of the electrical equipment.

[0129] In one embodiment, the control module 1003 is further configured to control the power consumption module to switch from the battery module to be balanced to the target power supply module to supply power if the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions; wherein the target power supply module is not multiple battery modules.

[0130] In one embodiment, the acquisition module 1001 is further configured to continuously perform SOC acquisition processing of multiple battery modules to obtain the updated SOC of multiple battery modules.

[0131] The determination module 1002 is also used to determine the battery modules to be balanced based on the updated SOC if the updated SOC of multiple battery modules does not meet the preset balancing conditions, so as to obtain the updated battery modules to be balanced.

[0132] The control module 1003 is also used to control the power consumption module to switch to the updated battery module to be balanced for power supply until the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions.

[0133] It should be noted that the power module includes at least one of the power management system and the high-voltage contactor, ensuring uninterrupted power supply to the power management system and continuous power supply to the high-voltage contactor during startup and maintenance, thereby improving the stability and safety of the energy storage system.

[0134] The capacity balancing device for the energy storage system provided in this embodiment determines whether the SOC of multiple battery modules in the target battery cluster meets the preset balancing conditions based on the SOC of each battery module in the target battery cluster. In the case of SOC imbalance, the device identifies the battery modules to be balanced based on the SOC of multiple battery modules, and then controls the battery modules to be balanced to supply power to the power-consuming modules. On the one hand, it can achieve SOC balancing of multiple battery modules in the target battery cluster without the need for other cooling methods, make reasonable use of the excess energy of the battery modules to be balanced, reduce energy loss, reduce the load on environmental control systems such as air conditioning, save energy, and improve safety. On the other hand, since the power-consuming modules in the energy storage system are changed from conventional single-path power supply to multi-path power supply, the reliability of the power-consuming modules is guaranteed, thereby improving the overall communication stability of the energy storage system.

[0135] In addition, this disclosure also provides an energy storage system, including: having at least one battery cluster and the capacity balancing device of the energy storage system described above, wherein the battery cluster includes a power consumption module and multiple battery modules, and the stability of the energy storage system is improved by combining the capacity balancing device of the energy storage system with the capacity balancing device described above, while having better balancing efficiency and reducing energy consumption.

[0136] Figure 11 A schematic diagram of the structure of an energy storage system provided in an embodiment of this disclosure is shown. Figure 11 As shown, the energy storage system 1100 provided in this embodiment includes a battery cluster 1101 and a battery management system (BMS) 1102. The BMS 1102 serves as a capacity balancing device for the energy storage system.

[0137] The battery cluster 1101 includes multiple battery modules 11011. The battery cluster 1101 is connected to a control switch 1103. The control switch 1103 is connected to the battery management system 1102 through a voltage conversion module 1104. The control switch 1103 can switch out the battery modules with unbalanced SOC. After voltage conversion by the voltage conversion module 1104, the voltage is converted to supply power to the battery management system BMS 1102. The BMS 1102 supplies power to the high-voltage contactor 1105. The voltage conversion module 1104 can be a DC-DC converter module, which is used to convert the voltage input from the battery modules into a supply voltage suitable for the power-consuming modules (such as BMS 1102).

[0138] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0139] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0140] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0141] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for capacity equalization of an energy storage system, characterized by, The energy storage system comprises at least one battery cluster, and the battery cluster comprises a power consumption module and a plurality of battery modules, and the method comprises: obtaining the residual capacity SOC of each battery module in a target battery cluster; wherein the target battery cluster is one of the at least one battery cluster; if the SOCs of the plurality of battery modules in the target battery cluster do not satisfy a preset balancing condition, determining a battery module to be balanced from the plurality of battery modules according to the SOCs of the plurality of battery modules; controlling the power consumption module to switch to the battery module to be balanced for power supply, so that the SOCs of the plurality of battery modules in the target battery cluster satisfy the preset balancing condition; wherein the determining of the battery module to be balanced from the plurality of battery modules according to the SOCs of the plurality of battery modules comprises: calculating the average value of the SOCs of the plurality of battery modules, and determining the upper limit value of the SOC of each battery module according to the average value of the SOCs of the plurality of battery modules; screening a target battery module from the plurality of battery modules, which is greater than the upper limit value of the SOC; if the number of the target battery modules is more than one, calculating the difference between the SOCs of any two target battery modules; if the difference between the SOCs of at least two target battery modules is less than or equal to a preset difference threshold, determining the at least two target battery modules as the battery module to be balanced, so as to synchronously supply power to the power consumption module.

2. The capacity equalization method of an energy storage system according to claim 1, wherein, The determining of the battery module to be balanced from the plurality of battery modules according to the SOCs of the plurality of battery modules comprises: determining the battery module corresponding to the maximum SOC in the plurality of battery modules as the battery module to be balanced.

3. The capacity equalization method of an energy storage system according to claim 1, wherein, The method further comprises: if the number of the target battery modules is single, determining the target battery module as the battery module to be balanced.

4. The capacity equalization method of an energy storage system according to claim 1, wherein, After the determining of the battery module to be balanced from the plurality of battery modules according to the SOCs of the plurality of battery modules, and before the controlling of the power consumption module to switch to the battery module to be balanced for power supply, the method further comprises: performing voltage conversion on the output voltage of the battery module to be balanced, so that the converted voltage satisfies the power supply condition of the power consumption module.

5. The method of capacity equalization of an energy storage system of claim 1, wherein, After the controlling of the power consumption module to switch to the battery module to be balanced for power supply, the method further comprises: if the SOCs of the plurality of battery modules in the target battery cluster satisfy the preset balancing condition, controlling the power consumption module to switch from the battery module to be balanced to a target power supply module for power supply; wherein the target power supply module is not the plurality of battery modules.

6. The capacity equalization method of an energy storage system according to claim 1, wherein, After the controlling of the power consumption module to switch to the battery module to be balanced for power supply, the method further comprises: continuously performing the obtaining process of the SOCs of the plurality of battery modules to obtain updated SOCs of the plurality of battery modules; if the updated SOCs of the plurality of battery modules do not satisfy the preset balancing condition, continuously determining the battery module to be balanced according to the updated SOCs to obtain an updated battery module to be balanced; The use module is controlled to switch to the updated to-be-balanced battery module for power supply until the SOC of the plurality of battery modules in the target battery cluster meets the preset balancing condition.

7. The capacity equalization method of an energy storage system according to claim 1, wherein, The use module includes at least one of a power management system and a high-voltage contactor.

8. The capacity equalization method of an energy storage system according to claim 1, wherein, The method further includes: If the difference between the maximum value of the SOC of the battery modules in the target battery cluster and the minimum value of the SOC of the battery modules is greater than a preset SOC threshold, or the difference between the SOC of any two battery modules in the target battery cluster is greater than the preset SOC threshold, it is determined that the SOC of the battery modules in the target battery cluster does not meet the preset balancing condition.

9. A capacity equalization device for an energy storage system, comprising: The energy storage system includes at least one battery cluster, and the device includes: An acquisition module is configured to acquire the SOC of each battery module in a target battery cluster; the target battery cluster is one of the at least one battery cluster; A determination module is configured to determine, if the SOC of the plurality of battery modules in the target battery cluster does not meet a preset balancing condition, to-be-balanced battery modules from the plurality of battery modules according to the SOC of the plurality of battery modules; A control module is configured to control the use module to switch to the to-be-balanced battery modules for power supply, so that the SOC of the plurality of battery modules in the target battery cluster meets the preset balancing condition. The determination module is further configured to calculate the average value of the SOC of the plurality of battery modules, and determine an upper limit value of the SOC of each battery module according to the average value of the SOC of the plurality of battery modules; filter target battery modules greater than the upper limit value of the SOC from the plurality of battery modules; if the number of the target battery modules is greater than one, calculate the difference between the SOC of any two target battery modules; if the difference between the SOC of at least two target battery modules is less than or equal to a preset difference threshold, determine the at least two target battery modules as the to-be-balanced battery modules to synchronously supply power to the use module.

10. The capacity equalization apparatus of an energy storage system according to claim 9, wherein, The device further includes a voltage conversion module configured to convert the output voltage of the to-be-balanced battery modules, so that the converted voltage meets the power supply condition of the use module.

11. An energy storage system characterized by, The device further includes a voltage conversion module configured to convert the output voltage of the to-be-balanced battery modules, so that the converted voltage meets the power supply condition of the use module. The device further includes a voltage conversion module configured to convert the output voltage of the to-be-balanced battery modules, so that the converted voltage meets the power supply condition of the use module.

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