Large-scale energy storage system and forced balancing method thereof

Abstract

The present invention provides a large energy storage system and a forced balancing method thereof, the forced balancing method comprising the following steps: a forced command sending step: a host computer sends a forced balancing command; a forced balancing start processing step: after receiving the forced balancing command, the SBCU module determines whether the current conditions allow the forced balancing to be turned on, if allowed, automatically searches for the monomer to be balanced, records the position, and turns on the forced balancing; if not allowed, does not perform the operation; a forced command closing step: turns off the forced balancing. The present invention can conveniently turn on the balancing through the HMI or the host computer, does not require charging, reduces the power consumption, and reduces the time spent on turning on the balancing.

Description

Technical Field

[0001] The present invention relates to the field of energy storage, and in particular to a large-scale energy storage system and a forced balancing method thereof. Background Art

[0002] With the development of battery technology and the reduction of battery costs, more and more large-scale energy storage system projects are being built, participating in frequency regulation, peak regulation, network stabilization and other functions. During the system debugging and operation process, due to the complexity of the actual working conditions, the voltage of the battery cells is inconsistent due to factors such as the internal and external environment and working conditions. It is necessary to add a forced balancing function to achieve the purpose of improving the discharge capacity and service life of the battery. Under normal circumstances, balancing can only be turned on when the SBCU is in maintenance mode and the battery is fully charged, but the maintenance time is very long and charging is required. In order to turn on balancing, a lot of time, manpower and electricity are required. At the same time, if charging is not possible on site, balancing cannot be turned on, which has great limitations.

[0003] The invention patent CN110323802B discloses a charging equalization device and method for an energy storage system, which includes N energy storage units, an energy storage state acquisition unit, a charging power supply specification judgment unit, a charging control unit, and N charging execution units. The charging control unit selects a suitable charging power supply to charge the energy storage unit according to the voltage value required for charging the energy storage system and the real-time voltage and / or real-time temperature state information of each energy storage unit, so that the energy storage unit with lower voltage and / or lower temperature is charged first, thereby achieving the purpose of charging equalization, which is beneficial to improving the life and safety performance of the energy storage system. However, the above scheme has great limitations. Summary of the invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a large-scale energy storage system and a forced balancing method thereof.

[0005] A large energy storage system provided according to the present invention includes a host computer module, a PCS module, an SBCU module and an MBCU module, wherein:

[0006] Multiple battery clusters under each PCS module are connected in parallel, and each battery cluster is managed by an SBCU module;

[0007] The SBCU modules corresponding to all battery clusters under a single PCS are coordinated and managed through an MBCU module;

[0008] Multiple MBCU modules are connected to the host computer module, and the host computer module sends a balancing command to the SBCU module through the MBCU module.

[0009] Preferably, the host computer module and the MBCU module, and the MBCU module and the SBCU module are connected via a bus.

[0010] According to the present invention, a forced balancing method based on the above-mentioned large energy storage system includes the following steps:

[0011] Steps for sending forced command: The host computer sends a forced balancing command;

[0012] Forced balancing start processing steps: After receiving the forced balancing command, the SBCU module determines whether the current conditions allow the forced balancing to be turned on. If so, it automatically searches for the monomer that needs to be balanced, records the position, and turns on the forced balancing; if not, it does not perform the operation;

[0013] Steps to turn off the forced command: Turn off forced balancing.

[0014] Preferably, the host computer sends a forced balancing command, including manually controlling the host computer to send a forced balancing command, or the host computer monitors the battery data and automatically sends a command to start forced balancing when a set value is reached.

[0015] Preferably, shutting down forced balancing includes manually controlling the host computer to send a command to shut down forced balancing, or the host computer monitors the battery data, and after reaching the set value, automatically sends a command to shut down forced balancing, or the SBCU module monitors the single cell that is forced to be balanced, and when the single cell meets the conditions for shutting down balancing, the single cell automatically shuts down balancing.

[0016] Preferably, manually controlling the host computer to send a forced balancing command includes: when an operation is performed on the host computer to reduce the charging and discharging power to 0, the host computer sends a command to reduce the power to 0 to the MBCU module. After the charging and discharging power of the MBCU module is reduced to 0, a forced balancing operation is performed on the host computer. At this time, the host computer sends a forced balancing command to the SBCU module.

[0017] Preferably, the forced balancing start processing step includes: after the SBCU module receives the forced balancing command from the host computer, first determine whether the actual charging and discharging power drops to 0. If the actual charging and discharging power drops to 0, first clear the balancing record, then find the monomer that needs to be balanced according to the conditions, record its position, and then perform balancing; if the actual charging and discharging power does not drop to 0, the SBCU module does not allow balancing to be turned on.

[0018] Preferably, after receiving the equalization command, the SBCU modules each determine the equalization start-up conditions, and the SBCU modules do not interfere with each other.

[0019] Preferably, the manual control of the host computer sending a command to turn off forced balancing includes: when the host computer executes the operation of turning off forced balancing, the host computer sends a command to turn off forced balancing to each SBCU module through the field bus, and each SBCU module receives the command to stop forced balancing and controls all monomers that are being balanced to stop balancing.

[0020] Preferably, the host computer module may also be an HMI module.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention can conveniently start balancing through HMI or host computer, without charging, thus reducing power consumption and the time spent on starting balancing.

[0023] 2. The present invention overcomes the limitation of balanced opening and improves the available time of the system.

[0024] 3. The present invention sends a forced balancing command through the HMI or the host computer. When the SBCU receives the forced balancing command and the power and the single cell voltage meet the balancing conditions, the balancing can be started. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0026] Figure 1 This is the large-scale energy storage system architecture of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0028] like Figure 1As shown, the present invention provides a large energy storage system and a forced balancing method thereof. In the energy storage system, each battery cluster is equipped with an SBCU responsible for managing the battery cluster of the cluster. The SBCU is a cluster-level BMS. Each cluster-level SBCU is responsible for managing the batteries of the cluster, receiving instructions from the upper-level MBCU, and controlling the disconnection and closure of the batteries of the cluster. Multiple battery clusters under a PCS are connected in parallel, and there are multiple SBCUs. Then the SBCUs of all clusters communicate with the upper-level MBCU. The MBCU is the upper-level BMS (battery management system). The upper-level MBCU is responsible for coordinating and managing all battery clusters under a single PCS, such as sending commands to each SBCU to control its disconnection or closure of relays. Then, an HMI or a host computer is connected to the field bus loop of the upper-level MBCU and the cluster-level SBCU. The host computer is used to monitor data in real time, update the dominant program, and turn on and off forced balancing. The HMI or the host computer can send a balancing command to the SBCU of a cluster of batteries. The upper-level MBCU, the cluster-level SBCU and the HMI communicate with each other via the field bus.

[0029] A large energy storage system and a forced balancing method thereof provided in accordance with the present invention include forced balancing pre-processing: HMI or a host computer sends a forced balancing command, and there are two methods: method one: manually controlling the HMI or the host computer to send a forced balancing command; method two: the HMI or the host computer monitors the battery data, and automatically sends a command to start forced balancing after reaching the set value. Forced balancing start-up processing: After receiving the forced balancing command, the cluster-level SBCU determines whether the current conditions allow the forced balancing to be turned on. If allowed, it automatically searches for the single cell that needs to be balanced, records the position, and turns on the forced balancing. If not allowed, it does not turn on. After receiving the forced balancing command, each cluster-level SBCU executes it independently without interfering with each other. Forced balancing shutdown processing: There are three ways to shut down forced balancing: Method 1: Manually control the HMI or host computer to send a command to shut down forced balancing. At this time, the cluster-level SBCU shuts down forced balancing; Method 2: The HMI or host computer monitors the battery data. When the set value is reached, it automatically sends a command to shut down forced balancing. At this time, the cluster-level SBCU shuts down forced balancing; Method 3: The cluster-level SBCU monitors the monomer that is forced to be balanced. When the monomer meets the conditions for shutting down balancing, the monomer automatically shuts down balancing, which does not affect the balancing of other monomers under the cluster level.

[0030] The forced balancing pre-processing is specifically as follows: Method 1: When the operation of charging and discharging power is set to 0 on the HMI (human-machine interface) or the host computer, the HMI or the host computer sends a command to reduce the power to 0 to the MBCU. After the charging and discharging power of the MBCU is reduced to 0, a forced balancing operation is then performed on the HMI or the host computer. At this time, the HMI or the host computer sends a forced balancing command to the cluster-level SBCU through the field bus; Method 2: The HMI or the host computer monitors the battery data. When the start-up set value is reached, the HMI or the host computer automatically sends a forced balancing command to the cluster-level SBCU through the field bus.

[0031] The specific process of forced balancing is that after the cluster-level SBCU receives the forced balancing command from the HMI or host computer, it first determines whether the actual charge and discharge power (charge and discharge power and current) has dropped to 0. If the actual charge and discharge power has dropped to 0, it first clears the balancing record, then finds the monomer that needs to be balanced according to the conditions, records its position, and then performs balancing; if the actual charge and discharge power has not dropped to 0, the cluster-level SBCU is not allowed to start balancing. After receiving the balancing command, the cluster-level SBCUs each determine the balancing start condition, and the cluster-level SBCUs do not interfere with each other.

[0032] The specific forced balancing shutdown processing is as follows: Method 1: When the HMI or host computer executes the operation of shutting down forced balancing, the HMI or host computer sends a command to shut down forced balancing to each cluster-level SBCU through the field bus. Each cluster-level SBCU receives the command to stop forced balancing and then controls all monomers being balanced to stop balancing; Method 2: The HMI or host computer monitors the data. When the set value is reached, the HMI or host computer automatically sends a command to stop forced balancing to the cluster-level SBCU. At this time, each cluster-level SBCU receives the command to stop forced balancing, and all monomers being balanced stop balancing; Method 3: Each cluster-level SBCU monitors the single unit being balanced. When the single unit being balanced meets the conditions for stopping balancing, the single unit automatically stops balancing, and the balancing of other monomers is not affected.

[0033] When HMI turns on all cluster-level forced balancing under MBCU1, it first executes the power limit operation of 0 on the HMI. The HMI sends a power limit of 0 to the superior MBCU1 through the field bus. The superior MBCU1 limits the charging and discharging power to 0, and then executes the operation of turning on forced balancing on the HMI. The HMI sends a forced balancing command to all cluster-level SBCUs (SBCU1-1~SBCU1-N) under the superior MBCU1 through the field bus. After the cluster-level SBCU (SBCU1-1~SBCU1-N) receives the forced balancing command, it determines whether the actual power is 0 (current). If it is 0, it first clears the balancing storage, then looks for a monomer that meets the requirements for turning on forced balancing, records the monomer position and the required balancing time, and then turns on balancing. If it is not 0, it does not turn on balancing. It should be noted that after receiving the forced balancing command, the cluster-level SBCU (SBCU1-1~SBCU1-N) manages the balancing of its own cluster, and the cluster levels do not interfere with each other. The value can also be set in the HMI or host computer. The HMI or host computer automatically monitors the battery data. When the expected value is reached, a command to start forced balancing is automatically sent to the cluster-level SBCU.

[0034] When the HMI turns off the forced balancing of all clusters under MBCU1, the forced balancing operation is first executed on the HMI. The HMI sends a command to turn off forced balancing to the cluster-level SBCU (SBCU1-1~SBCU1-N) through the field bus. After receiving the command, the cluster-level SBCU (SBCU1-1~SBCU1-N) clears the balancing storage and exits forced balancing. Finally, the operation of canceling the power limit to 0 is executed on the HMI. The HMI sends a command to set the power to 0 to the upper-level MBCU1 through the field bus. After receiving the command, the upper-level MBCU1 restores the power. You can also set the value on the HMI or the host computer. The HMI or the host computer automatically monitors the battery data. When the expected value is reached, it automatically sends a command to turn off forced balancing to the cluster-level SBCU.

[0035] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A forced balancing method for a large energy storage system, characterized in that: Applied to large energy storage systems, which include host computer modules, PCS modules, SBCU modules and MBCU modules, among which: Multiple battery clusters under each PCS module are connected in parallel, and each battery cluster is managed by an SBCU module; The SBCU modules corresponding to all battery clusters under a single PCS are coordinated and managed through an MBCU module; Multiple MBCU modules are connected to the host computer module, and the host computer module sends a balancing command to the SBCU module through the MBCU module; The forced balancing method includes the following steps: Steps for sending forced command: The host computer sends a forced balancing command; Forced balancing start processing steps: After receiving the forced balancing command, the SBCU module determines whether the current conditions allow the forced balancing to be turned on. If so, it automatically searches for the monomer that needs to be balanced, records the position, and turns on the forced balancing; if not, it does not perform the operation; Steps to turn off the forced command: Turn off forced balancing.

2. The forced equalization method according to claim 1, characterized in that: The host computer module and the MBCU module, and the MBCU module and the SBCU module are connected through a bus.

3. The forced equalization method according to claim 1, characterized in that: The host computer sends a forced balancing command, including manually controlling the host computer to send a forced balancing command, or the host computer monitors the battery data, and when the set value is reached, a command to start forced balancing is automatically sent.

4. The forced equalization method according to claim 1, characterized in that: Turning off forced balancing includes manually controlling the host computer to send a command to turn off forced balancing, or the host computer monitors the battery data, and after reaching the set value, automatically sends a command to turn off forced balancing, or the SBCU module monitors the single cell that is forced to be balanced, and when the single cell meets the conditions for turning off balancing, the single cell automatically turns off balancing.

5. The forced equalization method according to claim 3, characterized in that: Manually controlling the host computer to send a forced balancing command includes: when the operation of reducing the charging and discharging power to 0 is executed on the host computer, the host computer sends a command to reduce the power to 0 to the MBCU module. After the charging and discharging power of the MBCU module is reduced to 0, a forced balancing operation is performed on the host computer. At this time, the host computer sends a forced balancing command to the SBCU module.

6. The forced equalization method according to claim 1, characterized in that: The forced balancing start processing steps include: after the SBCU module receives the forced balancing command from the host computer, first determine whether the actual charging and discharging power drops to 0. If the actual charging and discharging power drops to 0, first clear the balancing record, then find the monomer that needs to be balanced according to the conditions, record its position, and then perform balancing; if the actual charging and discharging power does not drop to 0, the SBCU module does not allow balancing to be turned on.

7. The forced equalization method according to claim 6, characterized in that: After receiving the equalization command, the SBCU modules each determine the equalization start-up conditions, and the SBCU modules do not interfere with each other.

8. The forced equalization method according to claim 4, characterized in that: The manual control of the host computer to send a command to close forced balancing includes: when the host computer executes the operation of closing forced balancing, the host computer sends a command to close forced balancing to each SBCU module through the field bus, and each SBCU module receives the command to stop forced balancing and controls all monomers that are being balanced to stop balancing.

9. The forced equalization method according to claim 1, characterized in that: The host computer module may also be an HMI module.

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