Energy storage system and control method thereof

Abstract

The present invention discloses an energy storage system and a control method thereof. The energy storage system includes a plurality of battery packs connected in parallel. The control method of the energy storage system includes: establishing a communication connection between the plurality of battery packs so that each battery pack can respectively and regularly send its own data related to the hiccup mode to all battery packs except itself; determining one of the plurality of battery packs as the main battery pack; the main battery pack selects one of the battery packs as the battery pack entering the hiccup mode according to the data related to the hiccup mode of all the battery packs, and sends it to the other battery packs; the battery pack determined to enter the hiccup mode determines whether it meets the conditions for entering the hiccup mode, and if so, the battery pack determined to enter the hiccup mode notifies all other battery packs to enter the standby mode in a broadcasting manner, and then starts to run the hiccup mode. The present invention can reduce the power consumption of the battery under light load or no-load conditions and improve the overall efficiency.

Description

Technical Field

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

[0002] In order to adapt to different capacities, the battery packs in the home energy storage system generally need to be connected in parallel. To solve the problem of connecting multiple battery packs in parallel, some existing technologies try to connect DCDC (Direct Current-Direct Current) in series behind the battery pack to increase the voltage of the battery pack. In this way, on the one hand, the voltage on the high-voltage side after the series connection can be adjusted, and the current of the battery pack can also be controlled, which is convenient for parallel expansion at any time; on the other hand, after the voltage of the battery pack is increased, the wire diameter of the parallel cable of the battery pack can be smaller, saving some costs.

[0003] However, the newly introduced DCDC itself consumes power; when the output power is large, the power consumption is not too significant, but when the output power itself is very small (such as when no-load or light-loaded), the power consumed by DCDC cannot be ignored relative to the power of the battery pack.

[0004] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes an energy storage system and a control method thereof, which can reduce the power consumption of the battery under light load or no load conditions and improve the overall efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention discloses a control method for an energy storage system, wherein the energy storage system comprises a plurality of battery packs connected in parallel with each other, and the control method for the energy storage system comprises the following steps:

[0008] S1: establishing communication connections between the plurality of battery packs so that each battery pack can periodically send its own data related to the hiccup mode to all the battery packs except itself;

[0009] S2: determining one of the battery packs among the plurality of battery packs as a main battery pack;

[0010] S3: the master battery pack selects one of the battery packs as the battery pack to enter the hiccup mode according to the data related to the hiccup mode of all the battery packs, and sends the address of the battery pack selected to enter the hiccup mode to each of the other battery packs;

[0011] S4: The battery pack determined to have entered the hiccup mode determines whether it meets the conditions for entering the hiccup mode. If yes, execute step S5;

[0012] S5: The battery pack determined to enter the hiccup mode notifies all other battery packs to enter the standby mode in a broadcasting manner, and then starts to operate in the hiccup mode.

[0013] Preferably, the data related to the hiccup mode in step S1 includes at least one of its own cell current and cell power, its own address, its own battery SOC and the address of the battery pack selected by the main battery pack to enter the hiccup mode.

[0014] Preferably, step S2 specifically includes: determining the battery pack with the smallest address among the multiple battery packs as the main battery pack.

[0015] Preferably, in step S3, the main battery pack selects the battery pack with the highest battery SOC among all the battery packs as the battery pack that enters the hiccup mode.

[0016] Preferably, the condition for entering the hiccup mode in step S4 is: the electrical parameters of all battery cells remain at a positive value less than a first preset threshold value within a first preset time, wherein the electrical parameter is the average current, average power or total power, and a positive value of the electrical parameter indicates that all battery cells are in a discharged state.

[0017] Preferably, step S5 further includes:

[0018] If it is monitored that the cumulative running time of the battery pack running in hiccup mode exceeds a second preset time, the battery pack running in hiccup mode exits the hiccup mode, and notifies all other battery packs to exit the standby mode by broadcasting, and notifies the master battery pack to clear the address of the battery pack selected to enter the hiccup mode, and returns to step S3.

[0019] Preferably, step S5 further includes:

[0020] If the battery pack running the hiccup mode detects a charging current during the voltage rise period, the hiccup mode is exited, and all other battery packs are notified to exit the standby mode by broadcasting;

[0021] If any of the battery packs detects that the bus voltage exceeds the second preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, wherein the difference between the overvoltage protection point of the bus voltage and the second preset threshold is greater than the third preset threshold, and the third preset threshold is a positive number.

[0022] Preferably, step S5 further includes:

[0023] If the battery pack running the hiccup mode detects that the load is greater than the fourth preset threshold value during the voltage rise period, the battery pack exits the hiccup mode and notifies all other battery packs to exit the standby mode by broadcasting;

[0024] If any of the battery packs detects that the bus voltage is lower than the fifth preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, wherein the difference between the fifth preset threshold and the undervoltage protection point of the bus voltage is greater than the sixth preset threshold, and the sixth preset threshold is a positive number.

[0025] Preferably, step S4 also includes, if not, the battery pack determined to have entered the hiccup mode repeats the step of determining whether it satisfies the conditions for entering the hiccup mode within a third preset time; if the battery pack determined to have entered the hiccup mode determines that it satisfies the conditions for entering the hiccup mode within the third preset time, then step S5 is continued to be executed; otherwise, step S3 is returned to.

[0026] In a second aspect, the present invention further discloses an energy storage system, comprising a plurality of battery packs connected in parallel, wherein the energy storage system controls the plurality of battery packs using the control method of the energy storage system as described in the first aspect.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: the energy storage system and control method thereof proposed in the present invention realize coordination among multiple battery packs by establishing communication connections between multiple battery packs, determine one battery pack as a master battery pack, and after the master battery pack specifies the battery pack to enter the hiccup mode according to the data related to the hiccup mode of all battery packs, the designated battery pack operates in the hiccup mode, and all other battery packs operate in the standby mode, thereby reducing the power consumption of the battery of the entire energy storage system under light load or no load conditions and improving the overall efficiency; further solving the power consumption problem of the DCDC modules connected in series under low output power conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the control method of the energy storage system disclosed in the first embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0030] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and circuit / signal communication.

[0031] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] The key terms involved in the present invention are first described in detail below.

[0034] Hiccup mode: A state in which the system runs with PWM (Pulse width modulation wave) waves part of the time and stops PWM waves part of the time in order to reduce system losses, relying on energy storage elements in the system to support a period of time, reducing high-frequency switching time (reducing switching losses), and thus improving light-load efficiency.

[0035] Standby mode: The DCDC (Direct Current-Direct Current) of the battery pack stops sending PWM waves, and only the auxiliary source is in working state, which is a state with relatively low power consumption.

[0036] Based on the problems existing in the prior art, the present invention proposes a solution for allowing the battery pack to operate in hiccup mode, so as to reduce the power consumption of the battery under light load or no-load conditions and improve the overall efficiency; thereby further solving the power consumption problem of the series-connected DCDC modules under low output power conditions.

[0037] For a single battery pack, the hiccup mode is relatively easy to implement. However, for multiple battery packs, it is necessary to coordinate and synchronize the actions of each battery pack and consider more factors. Figure 1 As shown, in the first embodiment of the present invention, a control method of an energy storage system is proposed to solve the problem of hiccups of multiple battery packs. The energy storage system includes multiple battery packs connected in parallel. The control method of the energy storage system includes the following steps:

[0038] S1: establishing communication connections between multiple battery packs so that each battery pack can periodically send its own data related to the hiccup mode to all battery packs except itself;

[0039] Among them, the data related to the hiccup mode of each battery pack itself includes at least one of the battery cell current and battery cell power of the corresponding battery pack itself, the address of the corresponding battery pack itself, the battery SOC of the corresponding battery pack, and the address of the battery pack that selects to enter the hiccup mode.

[0040] S2: determining one of the multiple battery packs as a main battery pack;

[0041] Among them, the battery pack with the smallest address among the multiple battery packs is determined as the main battery pack.

[0042] S3: The master battery pack selects one of the battery packs as the battery pack to enter the hiccup mode based on the data related to the hiccup mode of all the battery packs, and sends the address of the battery pack selected to enter the hiccup mode to the other battery packs;

[0043] The main battery pack selects the battery pack with the highest battery SOC among all the battery packs as the battery pack that enters the hiccup mode based on the data related to the hiccup mode of all the battery packs.

[0044] S4: The battery pack determined to have entered the hiccup mode determines whether it meets the conditions for entering the hiccup mode. If yes, execute step S5;

[0045] Among them, the condition for entering the hiccup mode is: the electrical parameters of all battery cells remain at a positive value less than a first preset threshold within a first preset time, the electrical parameters are average current, average power or total power, and a positive value of the electrical parameter indicates that all battery cells are in a discharged state.

[0046] If the battery pack determined to enter the hiccup mode determines that it does not meet the conditions for entering the hiccup mode, it means that the current energy storage system is not in a low output power state, and each battery pack does not need to enter the hiccup mode or standby mode. However, in a further scheme, it is possible to repeatedly confirm whether the battery pack determined to enter the hiccup mode meets the conditions for entering the hiccup mode within a period of time. If the conditions for entering the hiccup mode are not met, it means that the energy storage system is not in a light load state. In this way, after a period of time, the main battery pack can be coordinated to reselect the battery pack entering the hiccup mode. That is, further, step S4 also includes: if not (that is, the battery pack determined to enter the hiccup mode determines that it does not meet the conditions for entering the hiccup mode), the battery pack determined to enter the hiccup mode repeats the step of determining whether it meets the conditions for entering the hiccup mode within a third preset time. If the battery pack determined to enter the hiccup mode determines that it meets the conditions for entering the hiccup mode within the third preset time, then continue to execute step S5, otherwise, return to step S3.

[0047] S5: The battery pack determined to have entered the hiccup mode notifies all other battery packs to enter the standby mode by broadcasting, and then starts to run the hiccup mode.

[0048] Further, after determining that the battery pack that has entered the hiccup mode is running in the hiccup mode, the step further includes the following steps:

[0049] If it is monitored that the cumulative operation time of the battery pack running in the hiccup mode exceeds the second preset time, the battery pack running in the hiccup mode exits the hiccup mode, and notifies all other battery packs to exit the standby mode by broadcasting, and notifies the master battery pack to clear the address of the battery pack selected to enter the hiccup mode, and returns to step S3;

[0050] If a battery pack running in hiccup mode detects a charging current during voltage rise, it exits hiccup mode and notifies all other battery packs to exit standby mode by broadcasting;

[0051] If any battery pack detects that the bus voltage exceeds the second preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, wherein the difference between the overvoltage protection point of the bus voltage and the second preset threshold is greater than the third preset threshold, and the third preset threshold is a positive number;

[0052] If the battery pack running the hiccup mode detects that the load is greater than the fourth preset threshold value during the voltage rise period, the battery pack exits the hiccup mode and notifies all other battery packs to exit the standby mode by broadcasting;

[0053] If any battery pack detects that the bus voltage is lower than the fifth preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, where the difference between the fifth preset threshold and the undervoltage protection point of the bus voltage is greater than the sixth preset threshold, and the sixth preset threshold is a positive number.

[0054] The control method of the energy storage system proposed in the first embodiment of the present invention aims at the hiccup problem of multiple battery packs connected in parallel, realizes the coordination and synchronization of the actions between the battery packs, and realizes a unified allocation method of the battery pack working mode, thereby reducing the power consumption of the battery under light load or no load conditions and improving the overall efficiency; and further solves the power consumption problem of the DCDC modules connected in series under low output power conditions.

[0055] The control method of the energy storage system disclosed in the first embodiment of the present invention is further described in detail below with reference to a specific embodiment.

[0056] To solve the problem of multiple packets burping, coordination between packets is required. In this specific embodiment, CAN (Controller Area Network) communication is adopted, and a communication protocol is designed to achieve the coordination of multiple packets burping. The specific implementation process is as follows:

[0057] A1: How to select a hiccup pack (i.e. a battery pack that enters hiccup mode)

[0058] When a system containing multiple battery packs connected in parallel wants to implement the hiccup mode, because the battery packs are connected in parallel, not all of the battery packs can run the hiccup mode together. This will cause current circulation problems between the battery packs. Therefore, only one battery pack runs the hiccup mode at a time, and the other battery packs are in standby mode.

[0059] Since the hiccup mode consumes the energy of its own battery pack, in this solution, the battery pack with a higher SOC (State of Charge) is selected to run the hiccup mode, and all other battery packs are in standby mode.

[0060] At present, through protocol design and based on the timed broadcast mechanism, each battery pack regularly broadcasts its data related to the hiccup mode to other devices in the energy storage system. In this way, each device in the system uses a list to maintain the data related to the hiccup mode of all battery packs in the entire system. The data related to the hiccup mode includes the address, battery SOC, cell current or power (either one is fine), and the hiccup package address (that is, the address of the battery pack selected by the main battery pack to enter the hiccup mode).

[0061] Taking three battery packs as an example, tables of data related to the hiccup mode are established for the three battery packs, respectively, as shown in Tables 1 to 3 below, where the column of cell current in the table can also be replaced with cell power:

[0062] Table 1 Pack1: Address 0x60

[0063]

[0064] Table 2 Pack2: Address 0x61 (this battery pack is currently a hiccup pack)

[0065]

[0066] Table 3 Pack3: Address 0x62

[0067]

[0068] Since there is a time difference in the data transmission process, the data maintained by each battery pack may be inconsistent at the same time. In order to ensure the uniqueness of the hiccup package (i.e. the battery pack that enters the hiccup mode), this solution also specifies a battery pack as the main battery pack, and the main battery pack selects the battery pack with the largest battery SOC at the same time, which can ensure the uniqueness of the hiccup package. The selected hiccup package is identified by the address and placed in the "hiccup package address" field of the main battery pack, and then the record of the main battery pack is transmitted to all other battery packs through the timed broadcast mechanism.

[0069] Among them, the method of selecting the main battery pack is: using the battery pack with the smallest address as the main battery pack; because the battery pack with the smallest address usually has the highest communication priority, the battery pack with the smallest address is selected as the main battery pack in this solution to further improve communication efficiency; in this way, each battery pack can find the main battery pack by the smallest address in the table it maintains, and then determine which battery pack is the current hiccup pack according to the "hiccup pack address" in the main battery pack record. In other embodiments, the battery pack with the largest address can also be used as the main battery pack, or any battery pack can be selected as the main battery pack.

[0070] A2: Hiccup entry conditions and working modes of each package

[0071] When the hiccup package address is "0", the hiccup package is selected from the list. After the hiccup package is selected, the energy storage system synchronizes the records of the main battery pack to each battery pack in the energy storage system through a timed broadcast mechanism. Each battery pack in the energy storage system compares its own address with the "hiccup package address" in the main battery pack record. If they are the same, it means that it is selected. If they are different, it is ignored.

[0072] Determine whether you are the battery pack of the hiccup pack and whether the following two conditions are met. Only when both conditions are met will you enter the hiccup mode:

[0073] a. The average current or average power or total power of all cells is positive (i.e., in discharge state) and is less than a preset threshold;

[0074] b. Continuously meet condition a for a certain period of time (e.g. 5s, 10s);

[0075] When the battery pack that determines that it is a hiccup pack meets the above two conditions at the same time, it indicates that the energy storage system is in a light load or no-load state at this time, and it can start to enter the hiccup mode. Before running the hiccup mode, all other battery packs are notified by broadcasting to enter the standby mode and turn off the PWM wave. After that, the battery pack that determines that it is a hiccup pack (i.e., the hiccup pack) starts to run the hiccup mode. Since all other battery packs are in standby mode, the power consumption is very low. Only the hiccup pack is in intermittent working mode, maintaining the bus to supply power to small loads. In this way, the switching loss of the energy storage system is minimized, thereby reducing the power consumption of the energy storage system. This is the principle of reducing power consumption in the hiccup mode.

[0076] A3: Exit conditions of hiccup mode

[0077] The hiccup mode will not continue forever. After a certain period of time, the energy of the hiccup pack will decrease, so it is necessary to exit the hiccup mode. At the same time, when the user starts charging or suddenly increases the load, the system also needs to be able to exit the hiccup mode in time and start normal operation, otherwise it may cause the battery pack busbar to overvoltage or undervoltage, causing the energy storage system to power off.

[0078] In this solution, the hiccup mode is exited when any of the following conditions are detected:

[0079] (1) Exiting the hiccup mode after a period of execution: After the hiccup package has been executed for a certain period of time, the hiccup package needs to be replaced due to the energy loss of the hiccup package. At this time, it is necessary to exit the hiccup mode and let the main battery pack reselect the hiccup package.

[0080] Specifically, after the hiccup package starts running, when the accumulated running time reaches the specified time (such as 10 minutes), the hiccup mode is exited, and other packages are notified by broadcast to exit the standby mode, and the main battery package is notified to clear the hiccup package address.

[0081] (2) Exit when charging: When the battery pack is being charged, you need to exit the hiccup mode.

[0082] In the hiccup mode, when PWM is working normally, the current can be detected normally; when the current reverse is detected, it is charged, and then the hiccup mode is exited. In the hiccup mode, when PWM is turned off, the current cannot be detected. At this time, only the rapid change of voltage can be detected. By judging whether the voltage rises sharply, it can be judged whether it is currently charged. Therefore:

[0083] For relatively small charging situations, the load direction can be detected during the voltage rise period of the hiccup (PWM normal drive). When the charging current is detected, it means that charging has started, the hiccup is exited, and all other battery packs are broadcast to exit standby mode.

[0084] In the case of a sudden increase in charging energy, the bus rises rapidly. Any battery pack can exit the hiccup mode or standby mode by detecting that the bus voltage exceeds a certain threshold (the threshold is smaller than the overvoltage protection point of the bus voltage, and the overvoltage protection point of the bus voltage minus the threshold is greater than a positive number, so that the bus voltage threshold when exiting the hiccup mode is still a certain distance away from the overvoltage protection point, ensuring that fault protection will not be caused before the current voltage stabilizes), and broadcasts that all other battery packs have exited the hiccup mode or standby mode.

[0085] (3) Exit when the load increases: When the discharge load increases and reaches a certain threshold, the hiccup mode needs to be exited.

[0086] In the hiccup mode, when PWM is working normally, the current can be detected normally. In the hiccup mode, when PWM is turned off, the current cannot be detected. Only the rapid change of voltage can be detected. By judging whether the voltage drops sharply, it can be judged whether the light load mode needs to be exited and high power output is required. It is similar to the exit detection in the charging situation, except that the voltage is judged to drop sharply. Therefore:

[0087] For a relatively small load increase, the load size can be detected during the voltage rise period of the hiccup (PWM normal drive). When it is detected that the load is greater than a certain threshold, the hiccup is exited and other packets are broadcast to exit the standby mode.

[0088] For a sudden increase in a large load, the bus drops quickly. Any packet can exit hiccup by detecting that the bus voltage is lower than a certain threshold (the threshold must be greater than the undervoltage protection point of the bus voltage, and the threshold minus the undervoltage protection point of the bus voltage is greater than a positive number, so that the bus voltage threshold when exiting the hiccup mode is still a certain distance away from the undervoltage protection point, ensuring that fault protection will not be caused before the current voltage stabilizes), and broadcast other packets to exit the hiccup or standby mode.

[0089] In summary, in this solution, after a battery pack runs in hiccup mode, on the one hand, a clock trigger condition is set to prevent a single battery pack from running in hiccup mode all the time; on the other hand, two events are judged: the first is whether the current battery pack is charged, and the second is to exit the light load mode, and the output power of the battery pack needs to be increased. If the above two situations exist, it is necessary to exit the hiccup mode, and the current voltage and current need to be judged for the above two events: a. The voltage exceeds the upper limit value, and the upper limit value must be lower than the overvoltage protection point (OVP point, which indicates that the battery pack is charged; b. The voltage is lower than the lower limit value, and the lower limit value must be higher than the undervoltage protection point (UVP point), which indicates that the battery pack is discharged and needs to provide high power output; c. The current is reversed, which also indicates that the battery pack is charged; d. The current is greater than the threshold (the state corresponding to the lower limit value of the voltage), which indicates that the battery pack is discharged and needs to provide high power output.

[0090] In a specific example of the present invention, a low-power battery pack parallel coordination method and system are proposed, which realizes coordination between multiple battery packs through CAN communication and a set communication protocol to reduce power consumption in light load mode. The energy storage system includes multiple battery packs, including a master battery pack and multiple slave battery packs. The master battery pack is configured to specify a certain battery pack to work in hiccup mode when the system is in a light load state, and all other battery packs work in standby mode to reduce the power consumption of the entire system in a light load state. Specifically, each battery pack is provided with a hiccup data field, which contains data: battery pack address, battery SOC, battery cell current / power, hiccup pack address. When the master battery pack specifies a certain battery pack as a hiccup pack, the battery pack address will be maintained in the hiccup pack address field and broadcast to each battery pack to ensure that each battery pack knows whether it is a hiccup pack. After the hiccup-related conditions are judged, the corresponding working mode can be entered in time (the battery pack designated as the hiccup pack works in the hiccup mode, and the other battery packs are all in standby mode).

[0091] The following is a further description of the CAN communication protocol used in the specific embodiments of the present invention.

[0092] (1) Communication frame format

[0093] This protocol uses the CAN bus extended frame as the transmission identification ID. The definition of the extended frame ID is shown in Table 4.

[0094] Table 4 Definition of extended frame ID

[0095]

[0096] (2) Several communication frames required for hiccup mode

[0097] Table 5 Several communication frames required for hiccup mode

[0098]

[0099] (3) Communication mechanism

[0100] Each battery pack in the energy storage system periodically reports the communication frames corresponding to ID2 and ID3. Each battery pack receives these two frames of information and fills in the local table (such as Table 1 to Table 3). Through the local table, each battery pack can know the information of all other battery packs.

[0101] After the hiccup package is selected, during the hiccup mode operation, it is necessary to notify all other battery packs to enter and exit the hiccup mode, which is achieved by broadcasting the communication frame corresponding to ID1.

[0102] Each battery pack will detect the communication frames sent to it and perform corresponding operations based on different frames.

[0103] After adopting the control method of the energy storage system proposed in the present invention, multiple parallel battery packs can realize the hiccup function in turn. The following Table 6 is a table comparing the power loss test of 3 battery packs without hiccups when no load and the control method of the energy storage system proposed in the present invention to control each battery pack to realize the hiccup mode of multiple battery packs.

[0104] Table 6 Comparison of power loss test of 3 battery packs without hiccups at no load and with the hiccups mode of the present invention

[0105]

[0106] From the above table, it can be seen that the power loss of the energy storage system when it is idling and not hiccuping is 136.44W, while the power loss of the energy storage system when the control method of the energy storage system proposed in the present invention is used to control each battery pack to achieve the hiccup mode of multiple battery packs is 86.748W. It can be seen that the power loss is reduced by 36%, and the effect is obvious.

[0107] Embodiment 2 of the present invention discloses an energy storage system, which includes a plurality of battery packs connected in parallel, and the energy storage system uses the control method of the energy storage system in Embodiment 1 to control the plurality of battery packs.

[0108] Embodiment 3 of the present invention discloses a computer-readable storage medium, in which a computer program is stored. The computer program is configured to be executable by a processor to execute the control method of the energy storage system in the above-mentioned embodiment 1.

[0109] Optionally, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0110] The background section of the present invention may contain background information about the problem or environment of the present invention, rather than describing the prior art by others. Therefore, the content contained in the background section is not an admission by the applicant that the prior art is available.

[0111] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of mutual contradiction, the technical personnel in this field can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope defined by the attached claims.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes a plurality of battery packs connected in parallel with each other, and the control method of the energy storage system includes the following steps: S1: establishing communication connections between the plurality of battery packs so that each battery pack can periodically send its own data related to the hiccup mode to all the battery packs except itself; S2: determining any one of the plurality of battery packs as a main battery pack; S3: the master battery pack selects one of the battery packs as the battery pack to enter the hiccup mode according to the data related to the hiccup mode of all the battery packs, and sends the address of the battery pack selected to enter the hiccup mode to each of the other battery packs; S4: The battery pack determined to have entered the hiccup mode determines whether it meets the conditions for entering the hiccup mode. If yes, execute step S5; S5: The battery pack determined to enter the hiccup mode notifies all other battery packs to enter the standby mode in a broadcasting manner, and then starts to run the hiccup mode; The data related to the hiccup mode include at least one of the battery cell current and the battery cell power, the address, the battery SOC and the address of the battery pack selected by the main battery pack to enter the hiccup mode.

2. The control method of the energy storage system according to claim 1, characterized in that: Step S2 specifically includes: determining the battery pack with the smallest address among the multiple battery packs as the main battery pack.

3. The control method of the energy storage system according to claim 1, characterized in that: In step S3, the main battery pack selects the battery pack with the highest battery SOC among all the battery packs as the battery pack that enters the hiccup mode.

4. The control method of the energy storage system according to claim 1, characterized in that: The condition for entering the hiccup mode in step S4 is that the electrical parameters of all battery cells remain at a positive value less than a first preset threshold value within a first preset time, wherein the electrical parameter is an average current, an average power or a total power, and a positive value of the electrical parameter indicates that all battery cells are in a discharged state.

5. The control method of the energy storage system according to claim 1, characterized in that: Step S5 also includes: If it is monitored that the cumulative running time of the battery pack running in hiccup mode exceeds a second preset time, the battery pack running in hiccup mode exits the hiccup mode, and notifies all other battery packs to exit the standby mode by broadcasting, and notifies the master battery pack to clear the address of the battery pack selected to enter the hiccup mode, and returns to step S3.

6. The control method of the energy storage system according to claim 1, characterized in that: Step S5 also includes: If the battery pack running the hiccup mode detects a charging current during the voltage rise period, the hiccup mode is exited, and all other battery packs are notified to exit the standby mode by broadcasting; If any of the battery packs detects that the bus voltage exceeds the second preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, wherein the difference between the overvoltage protection point of the bus voltage and the second preset threshold is greater than the third preset threshold, and the third preset threshold is a positive number.

7. The control method of the energy storage system according to claim 1, characterized in that: Step S5 also includes: If the battery pack running the hiccup mode detects that the load is greater than the fourth preset threshold value during the voltage rise period, the battery pack exits the hiccup mode and notifies all other battery packs to exit the standby mode by broadcasting; If any of the battery packs detects that the bus voltage is lower than the fifth preset threshold, the current battery pack exits its own hiccup mode or standby mode, and notifies all other battery packs to exit the hiccup mode or standby mode by broadcasting, wherein the difference between the fifth preset threshold and the undervoltage protection point of the bus voltage is greater than the sixth preset threshold, and the sixth preset threshold is a positive number.

8. The control method of the energy storage system according to claim 1, characterized in that: Step S4 also includes, if not, the battery pack determined to have entered the hiccup mode repeats the step of determining whether it satisfies the conditions for entering the hiccup mode within a third preset time; if the battery pack determined to have entered the hiccup mode determines that it satisfies the conditions for entering the hiccup mode within the third preset time, then continue to execute step S5; otherwise, return to step S3.

9. An energy storage system, characterized in that: The energy storage system comprises a plurality of battery packs connected in parallel with each other, and the energy storage system controls the plurality of battery packs by using the energy storage system control method according to any one of claims 1 to 8.

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