Parallel operation pre-charging method for energy storage system and energy storage system

Abstract

The invention relates to a parallel operation pre-charging method for an energy storage system and the energy storage system, and relates to the field of the energy storage system.The method is used for charging a parallel operation ES system in the energy storage system, the parallel operation ES system is connected with a PCS system, and the method comprises the steps that S1, the parallel operation ES system which completes parallel operation is obtained, and the PCS system is connected with the PCS system; the parallel operation ES system comprises a battery pack system and a charge-discharge circuit system which are connected with each other; s2, controlling a plurality of battery modules in the battery pack system to start a pre-charging mode through a charge-discharge circuit system, and charging a direct-current side capacitor of the parallel PCS system for at least a first preset time; and S3, obtaining a pre-charging result, merging a new battery module on the basis of the plurality of battery modules, and then repeating the step of starting the pre-charging mode. According to the scheme, power expansion or capacity expansion can be flexibly carried out on the energy storage system, the system stability is considered, the overheating or explosion risk is avoided, and then the safety performance of the parallel operation process is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage systems, and in particular to a parallel precharging method for energy storage systems and an energy storage system. Background Art

[0002] With the rapid development of the energy storage system market, the user side's demand for high-power and large-capacity energy storage systems is increasing day by day. From the perspective of actual business needs, it is necessary to flexibly expand the power or capacity of the energy storage system, which puts forward technical requirements for the pre-charging link of the energy storage system, especially the safety and stability of the energy storage system after parallel connection.

[0003] Therefore, the industry needs to design a parallel pre-charging solution that can flexibly expand the power or capacity of the energy storage system while taking into account system stability without the risk of overheating or explosion, thereby significantly improving the safety performance of the parallel process. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to design a parallel pre-charging method for an energy storage system, which can flexibly expand the power or capacity of the energy storage system, while taking into account the system stability without the risk of overheating or explosion, thereby significantly improving the safety performance of the parallel process.

[0005] In a first aspect, the present invention proposes a parallel precharging method for an energy storage system, which is used for charging a parallel ES system in the energy storage system, wherein the parallel ES system is connected to a PCS system, and the method comprises: S1, obtaining a parallel ES system that has completed parallel operation, wherein the parallel ES system comprises a battery pack system and a charging and discharging circuit system that are connected to each other; S2, controlling a plurality of battery modules in the battery pack system to start a precharging mode through the charging and discharging circuit system, charging the DC side capacitor of the parallel PCS system and charging the capacitor for at least a first preset time; S3, obtaining a precharging result, and adding a new battery module based on the plurality of battery modules, and then repeating the step of starting the precharging mode.

[0006] Its further technical solution is that, S1, obtains a parallel ES system that has completed parallel operation, and the parallel ES system includes a battery pack system and a charging and discharging circuit system that are connected to each other, including: S101, a single ES system is integrated with multiple battery modules and multiple inverters to form a parallel ES system, and the parallel ES system includes a battery pack system and a charging and discharging circuit system that are connected to each other.

[0007] Its further technical solution is that the parallel ES system includes a battery pack system, a BMS system is provided in the battery pack system, the BMS system is connected to the PCS system, and the BMS system is connected to the charging and discharging circuit system; the S2 controls multiple battery modules in the battery pack system to start the pre-charging mode through the charging and discharging circuit system, and charges the DC side capacitor of the PCS system implementing the parallel operation for at least a first preset time, including: S201, the parallel ES system detects the battery module with the smallest voltage value from multiple battery modules, which is defined as the minimum voltage battery module; S202, the BMS system of the parallel ES system controls the minimum voltage battery module to firstly charge the battery module through the charging and discharging circuit system. Start the pre-charge mode to charge the DC side capacitor of the PCS system that implements the parallel operation; S203, the BMS system of the parallel ES system controls the second battery module to the Nth battery module among the multiple battery modules to start the pre-charge mode, and together with the minimum voltage battery module, charge the DC side capacitor of the PCS system that implements the parallel operation; S204, continue charging for the first preset time, the BMS system of the parallel ES system controls the minimum voltage battery module to disconnect the pre-charge mode and convert it to the discharge mode as the starting point, and start the discharge and charge alternating mode. When the BMS system detects a current signal exceeding the preset current value, it uses the preset interval time as a cycle to periodically charge the PCS system using the discharge and charge alternating mode. Among them, the preset interval time is a technical parameter less than or equal to 100 milliseconds, for example, it can be 25 milliseconds, 50 milliseconds, or 75 milliseconds. The above scheme can provide a sufficiently large current for charging the DC side capacitor of the PCS system, while preventing short-circuit shocks; at this time, the second battery module to the Nth battery module maintain the state of the pre-charge mode.

[0008] Its further technical solution is that S3 obtains the pre-charging result, incorporates a new battery module based on multiple battery modules, and then repeats the step of starting the pre-charging mode, including: S301, after a preset M cycles, determines whether the pre-charging is completed normally at the first moment; S302, if the pre-charging is completed normally at the first moment, operates the entire system normally; S303, if the pre-charging is not completed normally at the first moment, incorporates a new battery module based on multiple battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to charge in the first mode, while other battery modules are charged in the second mode to obtain the pre-charging result; S304, then repeats the step of starting the pre-charging mode.

[0009] Its further technical solution is that, in S303, if the pre-charging is not completed normally at the first moment, a new battery module is added on the basis of multiple battery modules, and the BMS system of the parallel ES system controls the battery module with the minimum voltage to be charged in the first mode, while the other battery modules are charged in the second mode, and the pre-charging result is obtained, including: if the pre-charging is not completed normally at the first moment, a new battery module is added on the basis of multiple battery modules, and the BMS system of the parallel ES system controls the battery module with the minimum voltage to continue to be pre-charged and to continue to be charged in a hiccup manner after triggering an overcurrent, and at the same time, the battery modules other than the battery module with the minimum voltage are charged in the second mode. After the pre-charging of the second battery module to the Nth battery module lasts for twice the first preset time, the discharge-charge alternating mode is disconnected, and the pre-charging is normally completed at the second moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module, otherwise it continues to be incorporated in sequence until the number of new battery modules reaches five. If the voltage value Va of the minimum voltage battery module is reached when two, three or four new battery modules are incorporated during this period, the pre-charging is directly completed. If the voltage value on the battery port side still cannot reach the voltage value Va after the number of new battery modules reaches five, it is determined that the pre-charging cannot be completed. Among them, after continuing the pre-charging to trigger the overcurrent, the time for continuous charging in a hiccup manner can be twice the first preset time.

[0010] In the above scheme, regardless of whether the pre-charging is successfully completed, the pre-charging duration is at most twice the first preset time, so that the PCS system can work normally in the on-grid and off-grid state. Furthermore, the triggering of overcurrent is affected by the DC side capacitor parameters. Low power may not trigger overcurrent, while high power may trigger overcurrent once or multiple times. The specific situation can be understood by those skilled in the art.

[0011] In the second aspect, the present application also proposes an energy storage system, which is used to implement the parallel pre-charging method as described in the first aspect, and the energy storage system includes: a PCS system, a battery pack system, and a charging and discharging circuit system, the PCS system is connected to the battery pack system, the PCS system is connected to the charging and discharging circuit system, the charging and discharging circuit system is connected to the BMS system of the battery pack system, and the PCS system is connected to the BMS system of the battery pack system.

[0012] Furthermore, the PCS system includes a first pre-charging capacitor subsystem PC1, a second pre-charging capacitor subsystem PC2, and a third pre-charging capacitor subsystem PC3; the battery pack system includes a first battery module BM1, a second battery module BM2, and a third battery module BM3; the charging and discharging circuit system includes a first discharge pre-charging subsystem DH1, a first charging subsystem CH1, a second discharge pre-charging subsystem DH2, a second charging subsystem CH2, a third discharge pre-charging subsystem DH3, and a third charging subsystem CH3.

[0013] Furthermore, the first pre-charging capacity subsystem PC1 is connected to the first battery module BM1 via a first path, the second pre-charging capacity subsystem PC2 is connected to the second battery module BM2 via a first path, and the third pre-charging capacity subsystem PC3 is connected to the third battery module BM3 via a first path.

[0014] Furthermore, the first pre-charging capacity subsystem PC1 is connected to the first discharge pre-charging subsystem DH1, the first charging subsystem CH1, and the first battery module BM1 in sequence through the second path; the second pre-charging capacity subsystem PC2 is connected to the second discharge pre-charging subsystem DH2, the second charging subsystem CH2, and the second battery module BM2 in sequence through the second path; the third pre-charging capacity subsystem PC3 is connected to the third discharge pre-charging subsystem DH3, the third charging subsystem CH3, and the third battery module BM3 in sequence through the second path; wherein, the discharge circuit start or pre-charging circuit start of the first discharge pre-charging subsystem DH1, the discharge circuit start or pre-charging circuit start of the second discharge pre-charging subsystem DH2, and the discharge circuit start or pre-charging circuit start of the third discharge pre-charging subsystem DH3 are all controlled by the BMS system of the charging and discharging circuit system.

[0015] To sum up, for a multi-inverter multi-parallel ES system, the pre-charge capacity required by the inverter is very large. The traditional method uses a single energy storage battery to pre-charge a single inverter or multiple inverters, which easily leads to problems such as hot, heating and explosion of the pre-charge resistor. How to realize the grid-connected and off-grid pre-charging function for the inverter to make the entire system run stably. The use of a single energy storage battery pre-charging method can no longer meet the demand. The present invention uses multiple energy storage batteries to start in parallel at the same time to pre-charge multiple inverters in parallel, which can perfectly solve a series of technical problems such as insufficient pre-charging energy, pre-charging failure, and overheating of pre-charging resistors.

[0016] With the rapid development of the energy storage system market, the user-side demand for high-power and large-capacity energy storage systems is increasing day by day; from the perspective of actual business needs, the R&D team in the industry needs to flexibly expand the power or capacity of the energy storage system, which puts forward technical requirements for the pre-charging link of the energy storage system, especially the safety and stability of the energy storage system after parallel connection; based on this, the solution described in this application can flexibly expand the power or capacity of the energy storage system, while taking into account the stability of the system without the risk of overheating or explosion, thereby significantly improving the safety performance of the parallel connection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic flow chart of a parallel precharging method provided in an embodiment of the present invention.

[0020] Figure 2 Another schematic flow chart of the parallel precharging method provided in an embodiment of the present invention.

[0021] Figure 3 A circuit diagram of an energy storage system provided in an embodiment of the present invention.

[0022] Figure 4 Another circuit diagram of an energy storage system provided by an embodiment of the present invention.

[0023] Figure 5 A partial schematic diagram of an energy storage system provided in an embodiment of the present invention.

[0024] Figure 6 Another partial schematic diagram of the energy storage system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to one or any combination and all possible combinations of the associated listed items, and includes these combinations.

[0029] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0030] Example

[0031] See also Figures 1 to 6 ,in Figure 1 to Figure 2 A flow chart of a parallel pre-charging method for an energy storage system provided in an embodiment of the present invention. An embodiment of the present invention proposes a parallel pre-charging method for an energy storage system, which is used to charge a parallel ES system in an energy storage system, wherein the energy storage system includes a parallel ES system and a PCS system, wherein the parallel ES system is connected to the PCS system, and the method includes:

[0032] S1, obtaining a parallel ES system that has completed parallel operation, wherein the parallel ES system includes a battery group system and a charging and discharging circuit system that are connected to each other.

[0033] S2, controlling the plurality of battery modules in the battery pack system to start a pre-charging mode through a charging and discharging circuit system, charging the DC side capacitor of the parallel PCS system and lasting for at least a first preset time.

[0034] S3, obtaining the pre-charging result, incorporating a new battery module into the multiple battery modules, and then repeating the steps of starting the pre-charging mode.

[0035] In one embodiment, the step S1 is to obtain a parallel ES system that has completed parallel operation, wherein the parallel ES system includes a battery group system and a charging and discharging circuit system that are connected to each other, including:

[0036] S101, a single-machine ES system is combined with multiple battery modules and multiple inverters to form a parallel ES system, wherein the parallel ES system includes a battery pack system and a charging and discharging circuit system connected to each other.

[0037] In one embodiment, the parallel ES system includes a battery pack system, a BMS system is provided in the battery pack system, the BMS system is connected to the PCS system, and the BMS system is connected to the charging and discharging circuit system; S2 controls multiple battery modules in the battery pack system to start a pre-charging mode through the charging and discharging circuit system to charge the DC side capacitor of the parallel PCS system for at least a first preset time, including:

[0038] S201, the parallel ES system detects a battery module with the smallest voltage value from multiple battery modules, and defines it as the minimum voltage battery module.

[0039] S202, the BMS system of the parallel ES system controls the minimum voltage battery module to first start the pre-charge mode through the charging and discharging circuit system to charge the DC side capacitor of the parallel PCS system.

[0040] S203, the BMS system of the parallel ES system controls the second battery module to the Nth battery module among the multiple battery modules to start the pre-charging mode, and charges the DC side capacitor of the parallel PCS system together with the minimum voltage battery module.

[0041] S204, continuously charging for the first preset time, the BMS system of the parallel ES system controls the minimum voltage battery module to disconnect the pre-charge mode and convert it into the discharge mode as the starting point, and starts the discharge-charge alternating mode. When the BMS system detects a current signal exceeding the preset current value, it periodically charges the PCS system using the discharge-charge alternating mode with a preset interval time as a period.

[0042] Among them, the BMS system of the parallel ES system controls the minimum voltage battery module to disconnect the pre-charge mode and convert it into the discharge mode as the starting point. The pre-charge mode corresponds to the pre-charge loop, and the discharge mode corresponds to the discharge loop.

[0043] In one embodiment, the step S3, obtaining the pre-charging result, incorporating a new battery module into the plurality of battery modules, and then repeating the step of starting the pre-charging mode, includes:

[0044] S301, after a preset number of M cycles, determine whether the pre-charging is completed normally at the first moment.

[0045] S302, if the pre-charging is completed normally at the first moment, the whole system operates normally.

[0046] S303, if the pre-charging is not completed normally at the first moment, a new battery module is added based on multiple battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to be charged in the first mode, while the other battery modules are charged in the second mode to obtain the pre-charging result.

[0047] S304, then repeat the step of starting the pre-charge mode.

[0048] The preset M cycles are specifically set by an engineer, and further, the first moment may be reached after M cycles.

[0049] In one embodiment, if the pre-charging is not completed normally at the first moment, in S303, a new battery module is added based on the multiple battery modules, and the BMS system of the parallel ES system controls the battery module with the minimum voltage to be charged in the first mode, while the other battery modules are charged in the second mode, and the pre-charging result is obtained, including:

[0050] If the pre-charging is not completed normally at the first moment, a new battery module is added based on multiple battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to continue pre-charging and trigger overcurrent to continue charging in a hiccup manner. At the same time, the second battery module to the Nth battery module other than the minimum voltage battery module is pre-charged for twice the first preset time, and then the discharge and charge alternating mode is disconnected. When the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module, the pre-charging is completed normally at the second moment. Otherwise, the new battery modules are continued to be added in sequence until the number of new battery modules reaches five. If the voltage value Va of the minimum voltage battery module is reached when two, three or four new battery modules are added during this period, the pre-charging is completed directly. If the voltage value on the battery port side still cannot reach the voltage value Va after the number of new battery modules reaches five, it is judged that the pre-charging cannot be completed. Among them, after the number of new battery modules reaches five, the total number of battery modules is N+4; after the first moment, at least twice the first preset time is added to reach the second moment.

[0051] In the above scheme, if the pre-charging is not completed normally at the first moment, a new battery module is added on the basis of multiple battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to continue pre-charging and trigger overcurrent to continue charging in a hiccup manner, and at the same time, the second battery module to the Nth battery module other than the minimum voltage battery module are pre-charged for twice the first preset time, and then the discharge and charge alternating mode is disconnected, and the pre-charging is completed normally at the second moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module; otherwise, continue to add new battery modules in sequence until the number of new battery modules reaches five, and if the voltage value Va of the minimum voltage battery module is reached when two, three or four new battery modules are added during this period, the pre-charging is completed directly, which may include the following schemes;

[0052] Furthermore, if the pre-charging is not completed normally at the second moment, the pre-charging continues, and the minimum voltage battery module is identified in the state of two new battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to continue pre-charging and trigger overcurrent to continue charging in a hiccup manner, and at the same time, after the second battery module to the N+1th battery module other than the minimum voltage battery module is pre-charged for twice the first preset time, the discharge-charge alternating mode is disconnected, and the pre-charging is completed normally at the third moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module;

[0053] Further, if the pre-charging is not completed normally at the third moment, the merging continues, and the minimum voltage battery module is identified in the state of three new battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to continue pre-charging and trigger overcurrent to continue charging in a hiccup manner, and at the same time, after the second battery module to the N+2 battery module other than the minimum voltage battery module is pre-charged for twice the first preset time, the discharge-charge alternating mode is disconnected, and the pre-charging is completed normally at the fourth moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module;

[0054] Furthermore, if the pre-charging is not completed normally at the fourth moment, the pre-charging continues and the battery module with the minimum voltage is identified in the state of four new battery modules. The BMS system of the parallel ES system controls the battery module with the minimum voltage to continue pre-charging and continues to charge in a hiccup manner after triggering an overcurrent. At the same time, after the pre-charging of the second battery modules to the N+3th battery module other than the battery module with the minimum voltage continues for twice the first preset time, the discharge and charge alternating mode is disconnected, and the pre-charging is completed normally at the fifth moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the battery module with the minimum voltage.

[0055] With the rapid development of the energy storage system market, the user-side demand for high-power and large-capacity energy storage systems is increasing day by day; from the perspective of actual business needs, the R&D team in the industry needs to flexibly expand the power or capacity of the energy storage system, which puts forward technical requirements for the pre-charging link of the energy storage system, especially the safety and stability of the energy storage system after parallel connection; based on this, the solution described in this application can flexibly expand the power or capacity of the energy storage system, while taking into account the stability of the system without the risk of overheating or explosion, thereby significantly improving the safety performance of the parallel connection process.

[0056] The present invention also provides an energy storage system, see Figures 3 to 6, the energy storage system is used to implement the parallel pre-charging method described in any of the above embodiments, the energy storage system includes: a PCS system, a battery pack system, a charging and discharging circuit system, the PCS system is connected to the battery pack system, the PCS system is connected to the charging and discharging circuit system, the charging and discharging circuit system is connected to the BMS system of the battery pack system, and the PCS system is connected to the BMS system of the battery pack system. The technical effect of the energy storage system is that it can flexibly expand the power or capacity of the energy storage system, and take into account the stability of the system without the risk of overheating or explosion, thereby significantly improving the safety performance of the parallel process.

[0057] In one embodiment, the PCS system includes a first pre-charging capacitor subsystem PC1, a second pre-charging capacitor subsystem PC2, and a third pre-charging capacitor subsystem PC3; the battery pack system includes a first battery module BM1, a second battery module BM2, and a third battery module BM3; the charging and discharging circuit system includes a first discharge pre-charging subsystem DH1, a first charging subsystem CH1, a second discharge pre-charging subsystem DH2, a second charging subsystem CH2, a third discharge pre-charging subsystem DH3, and a third charging subsystem CH3.

[0058] The first pre-charging capacity subsystem PC1 is connected to the first battery module BM1 via a first path, the second pre-charging capacity subsystem PC2 is connected to the second battery module BM2 via a first path, and the third pre-charging capacity subsystem PC3 is connected to the third battery module BM3 via a first path.

[0059] The first pre-charging capacity subsystem PC1 is connected to the first discharge pre-charging subsystem DH1, the first charging subsystem CH1, and the first battery module BM1 in sequence through the second path; the second pre-charging capacity subsystem PC2 is connected to the second discharge pre-charging subsystem DH2, the second charging subsystem CH2, and the second battery module BM2 in sequence through the second path; the third pre-charging capacity subsystem PC3 is connected to the third discharge pre-charging subsystem DH3, the third charging subsystem CH3, and the third battery module BM3 in sequence through the second path; wherein, the discharge circuit start or pre-charging circuit start of the first discharge pre-charging subsystem DH1, the discharge circuit start or pre-charging circuit start of the second discharge pre-charging subsystem DH2, and the discharge circuit start or pre-charging circuit start of the third discharge pre-charging subsystem DH3 are all controlled by the BMS system of the charging and discharging circuit system.

[0060] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions, but such implementation should not be considered to be beyond the scope of the present invention.

[0061] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of each unit is only a logical function division, and there may be other division methods in actual implementation. For example, units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0062] The steps in the method of the embodiment of the present invention can be adjusted in order, combined and deleted according to actual needs. The units in the device of the embodiment of the present invention can be combined, divided and deleted according to actual needs. In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0063] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, terminal, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention.

[0064] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0065] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0066] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A parallel pre-charging method for an energy storage system, characterized in that: For charging a parallel ES system in an energy storage system, the parallel ES system being connected to a PCS system, the method comprising: S1, obtaining a parallel ES system that has completed parallel operation, wherein the parallel ES system includes a battery group system and a charging and discharging circuit system that are connected to each other; S2, controlling multiple battery modules in the battery pack system to start a pre-charging mode through a charging and discharging circuit system, charging the DC side capacitor of the PCS system implemented in parallel and lasting for at least a first preset time; S3, obtaining the pre-charging result, incorporating a new battery module into the multiple battery modules, and then repeating the steps of starting the pre-charging mode.

2. The parallel pre-charging method for an energy storage system according to claim 1, characterized in that: The step S1 is to obtain a parallel ES system that has completed parallel operation, wherein the parallel ES system includes a battery group system and a charging and discharging circuit system that are connected to each other, including: S101, a single-machine ES system is combined with multiple battery modules and multiple inverters to form a parallel ES system, wherein the parallel ES system includes a battery pack system and a charging and discharging circuit system connected to each other.

3. The parallel pre-charging method for an energy storage system according to claim 2, characterized in that: The parallel ES system includes a battery pack system, a BMS system is provided in the battery pack system, the BMS system is connected to the PCS system, and the BMS system is connected to the charging and discharging circuit system; S2 controls multiple battery modules in the battery pack system to start a pre-charging mode through the charging and discharging circuit system to charge the DC side capacitor of the parallel PCS system for at least a first preset time, including: S201, the parallel ES system detects a battery module with the smallest voltage value from among multiple battery modules, and defines it as the minimum voltage battery module; S202, the BMS system of the parallel ES system controls the minimum voltage battery module to first start the pre-charge mode through the charging and discharging circuit system to charge the DC side capacitor of the parallel PCS system; S203, the BMS system of the parallel ES system controls the second battery module to the Nth battery module among the multiple battery modules to start the pre-charging mode, and charges the DC side capacitor of the parallel PCS system together with the minimum voltage battery module; S204, continuously charging for the first preset time, the BMS system of the parallel ES system controls the minimum voltage battery module to disconnect the pre-charge mode and convert it into the discharge mode as the starting point, and starts the discharge-charge alternating mode. When the BMS system detects a current signal exceeding the preset current value, it periodically charges the PCS system using the discharge-charge alternating mode with a preset interval time as a period.

4. The parallel pre-charging method for an energy storage system according to claim 3, characterized in that: The step S3, obtaining the pre-charging result, adding a new battery module based on the multiple battery modules, and then repeating the step of starting the pre-charging mode, includes: S301, after a preset M cycles, determining whether the pre-charging is completed normally at the first moment; S302, if the pre-charging is completed normally at the first moment, the whole system is operated normally; S303: if the pre-charging is not completed normally at the first moment, a new battery module is added based on the multiple battery modules, and the BMS system of the parallel ES system controls the battery module with the minimum voltage to be charged in the first mode, and the other battery modules are charged in the second mode, and the pre-charging result is obtained; S304, then repeat the step of starting the pre-charge mode.

5. The parallel pre-charging method for an energy storage system according to claim 4, characterized in that: In S303, if the pre-charging is not completed normally at the first moment, a new battery module is added based on the multiple battery modules, and the BMS system of the parallel ES system controls the battery module with the minimum voltage to be charged in the first mode, and the other battery modules are charged in the second mode, and the pre-charging result is obtained, including: If the pre-charging is not completed normally at the first moment, new battery modules are added based on multiple battery modules, and the BMS system of the parallel ES system controls the minimum voltage battery module to continue pre-charging and continues to charge in a hiccup manner after triggering an overcurrent. At the same time, after the second battery modules to the Nth battery module other than the minimum voltage battery module are pre-charged for twice the first preset time, the discharge and charge alternating mode is disconnected, and the pre-charging is completed normally at the second moment when the voltage value on the battery port side changes until it reaches the voltage value Va of the minimum voltage battery module. Otherwise, the new battery modules continue to be added in sequence until the number of new battery modules reaches five. If the voltage value Va of the minimum voltage battery module is reached when two, three or four new battery modules are added during this period, the pre-charging is completed directly. If the voltage value on the battery port side still cannot reach the voltage value Va after the number of new battery modules reaches five, it is judged that the pre-charging cannot be completed.

6. An energy storage system, characterized in that: The energy storage system is used to implement the parallel pre-charging method according to claims 1 to 5, and the energy storage system includes: A PCS system, a battery pack system, and a charging and discharging circuit system, wherein the PCS system is connected to the battery pack system, the PCS system is connected to the charging and discharging circuit system, the charging and discharging circuit system is connected to the BMS system of the battery pack system, and the PCS system is connected to the BMS system of the battery pack system.

7. The energy storage system according to claim 6, characterized in that: The PCS system includes a first pre-charge capacitor subsystem PC1, a second pre-charge capacitor subsystem PC2, and a third pre-charge capacitor subsystem PC3; the battery pack system includes a first battery module BM1, a second battery module BM2, and a third battery module BM3; the charge-discharge circuit system includes a first discharge pre-charge subsystem DH1, a first charging subsystem CH1, a second discharge pre-charge subsystem DH2, a second charging subsystem CH2, a third discharge pre-charge subsystem DH3, and a third charging subsystem CH3; The first pre-charge capacity subsystem PC1 is connected to the first battery module BM1 via a first path, the second pre-charge capacity subsystem PC2 is connected to the second battery module BM2 via a first path, and the third pre-charge capacity subsystem PC3 is connected to the third battery module BM3 via a first path; The first pre-charging capacity subsystem PC1 is connected to the first discharge pre-charging subsystem DH1, the first charging subsystem CH1, and the first battery module BM1 in sequence through the second path; the second pre-charging capacity subsystem PC2 is connected to the second discharge pre-charging subsystem DH2, the second charging subsystem CH2, and the second battery module BM2 in sequence through the second path; the third pre-charging capacity subsystem PC3 is connected to the third discharge pre-charging subsystem DH3, the third charging subsystem CH3, and the third battery module BM3 in sequence through the second path; wherein, the discharge circuit start or pre-charging circuit start of the first discharge pre-charging subsystem DH1, the discharge circuit start or pre-charging circuit start of the second discharge pre-charging subsystem DH2, and the discharge circuit start or pre-charging circuit start of the third discharge pre-charging subsystem DH3 are all controlled by the BMS system of the charging and discharging circuit system.

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