Grouping parallel operation method for energy storage battery pack

Abstract

The invention discloses a grouping parallel operation method for an energy storage battery pack, and the method comprises the steps: firstly dividing a battery pack array into a plurality of subgroups, and enabling each subgroup to comprise a plurality of battery units; then, assigning one battery unit as a host in each subgroup, setting the other battery units as slaves, and realizing communication between the host and the slaves through a 485 communication protocol; secondly, establishing communication connection among the subgroups by using a CAN (Controller Area Network) communication protocol, and distributing a unique identification address for each subgroup; and finally, periodically sending a synchronization instruction to all the subgroups by the host, triggering the battery units in the subgroups to carry out self-identification and set address identifiers, and completing intra-group parallel operation. According to the method, the system design is simplified, the stability and reliability of the system are improved, and the working state of the large-scale parallel battery pack can be effectively managed and monitored, so that the user experience is improved. The method supports effective management of at most 256 battery units, and the expandability and flexibility of the system are remarkably enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery management, and in particular relates to a grouping and paralleling method for energy storage battery groups. Background Art

[0002] As the demand for energy storage system capacity continues to grow, the number of battery packs that need to be connected in parallel in practical applications is increasing. In order to meet the high capacity requirements, the complexity of system integration has also increased. Existing energy storage systems can usually connect up to 32 battery packs in parallel. However, when more than 32 battery packs need to be connected in parallel, the traditional parallel method not only makes the system design extremely complicated, but also reduces the stability and reliability of the system, which brings inconvenience to users.

[0003] A major problem faced by the prior art is that when more than a certain number (such as 32) of battery packs need to be connected in parallel, the traditional parallel connection method will cause the system design to become too complicated and affect the overall stability and reliability of the system. Summary of the invention

[0004] The object of the present invention is to provide a group parallel method for energy storage battery packs, by reasonably dividing a large number of battery cells into a number of sub-groups, and using the 485 communication protocol to communicate between the host and the slave within the sub-group, and using the CAN communication protocol to establish communication connections between the sub-groups, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention adopts the following technical solution: a grouping and paralleling method for energy storage battery groups, comprising the following steps:

[0006] a) Divide the battery array into multiple subgroups, each of which contains multiple battery cells; b) Designate a battery cell in each subgroup as the host, and set the remaining battery cells as slaves, and realize communication between the host and the slaves through the 485 communication protocol; c) Use the CAN communication protocol to establish communication connections between subgroups, and assign a unique identification address to each subgroup according to the pre-set address rules; d) The host periodically sends synchronization instructions to all subgroups, triggering the battery cells in the subgroup to self-identify, and set their respective address identifiers to complete the parallel connection within the group.

[0007] Preferably, the method further comprises:

[0008] e) Collect the status information of all battery cells in the subgroup and process them centrally through the host;

[0009] f) The subgroup host sends the collected status information to the central control system via the CAN bus;

[0010] g) The central control system performs data analysis and management based on the received status information.

[0011] h) When the system detects any fault, it sends instructions to the corresponding subgroup host via the CAN bus to perform fault diagnosis or repair measures.

[0012] Preferably, fault diagnosis includes but is not limited to short circuit detection and overheating protection measures.

[0013] Preferably, the subgroup division is performed according to the physical arrangement order of the battery pack array, and each subgroup contains the same number of battery cells.

[0014] Preferably, the selection of the master is based on a predefined position criterion, being the first battery cell in the subgroup.

[0015] Preferably, the unique identification address between subgroups is set by a hardware dip switch.

[0016] Preferably, the addresses of the battery cells in the subgroup are set in the order in which the synchronization instructions are received.

[0017] Preferably, the synchronization instruction includes a code for triggering the setting of the battery unit address, and the battery unit sets its own address identifier in sequence according to the code sequence in the received instruction.

[0018] Preferably, the code is a predetermined set of instructions for instructing the battery unit to enter an address setting mode and automatically configure the address in the order in which the instructions are received.

[0019] Technical effects and advantages of the present invention: Compared with the prior art, the present invention provides a grouping and paralleling method for energy storage battery groups, which has the following advantages:

[0020] The present invention divides a large number of battery cells into several subgroups reasonably, and uses the 485 communication protocol to communicate between the host and the slave within the subgroup, and uses the CAN communication protocol to establish communication connections between the subgroups. This method can not only simplify the design of the system, improve the stability and reliability of the system, but also effectively manage and monitor the working status of large-scale parallel battery packs, thereby improving the user experience. Through this method, effective management of up to 256 battery cells can be achieved, greatly improving the scalability and flexibility of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a grouping and paralleling method for energy storage battery groups according to the present invention;

[0022] Figure 2 It is a structural schematic diagram of a battery array of the present invention;

[0023] Figure 3A diagram of the DIP switch mode of the present invention;

[0024] Figure 4 A flow chart for determining an address for the present invention;

[0025] Figure 5 A diagram of the dial address of the battery array of the present invention;

[0026] Figure 6 Diagram of a frame for sending data for the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying 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 only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] The present invention provides a grouping and paralleling method for energy storage battery groups, comprising the following steps:

[0029] a) dividing the battery array into a plurality of subgroups, each subgroup comprising a plurality of battery cells; further, the subgroup division is performed according to the physical arrangement order of the battery array, and each subgroup comprises the same number of battery cells.

[0030] For example:

[0031] Assuming that the entire battery array consists of N battery cells, these cells need to be divided into M subgroups, each of which contains K battery cells (N = M × K, and N, M, K are all positive integers). Then, the algorithm formula for subgroup division can be expressed as:

[0032] Subgroup (m) = {n|n = m×K+k, k∈[0,K-1]}, m∈[0,M-1, where n is the index number of the battery cell (counting from 0), m is the index number of the subgroup (counting from 0), and k represents the index number of the battery cell in the subgroup (counting from 0). This formula means that each subgroup m contains battery cell index numbers from m×K to (m+1)×K-1.

[0033] For example, if an array contains 256 battery cells and we want to divide it into 16 subgroups, each containing 16 battery cells, then N = 256, M = 16, K = 16. Then, the result of the subgroup division will be:

[0034] Subgroup (0) = {0, 1, 2, ..., 15};

[0035] Subgroup (1) = {16, 17, 18, ..., 31}; ......

[0037] Subgroup (15) = {240, 241, 242, ..., 255}.

[0038] The number of battery cells in each subgroup is equal and is divided according to the physical arrangement order of the battery array.

[0039] Specifically, Figure 2 As shown, the entire energy storage battery system consists of an inverter (PCS) array and a battery array. The inverter array and the battery array are connected in parallel. In the entire system, the inverter array is the host and the battery array is the slave. CAN communication is used inside the inverter array. The battery array is divided into 16 groups, each with 16 battery packs. A total of 16*16=256 battery packs can be connected in parallel. 485 parallel communication is used inside the battery pack, and CAN communication is used to transmit data between groups. In the figure: the vertical 1-16 is represented by: from top to bottom, the code switch 0-15 indicates that there are 16 battery packs in the group; the horizontal 1-16 is represented by: from left to right, the code switch 0-15 indicates that there are 16 battery packs in the group.

[0040] The specific steps are as follows:

[0041] Initialize the system

[0042] Inverter array initialization: Start all inverters and establish communication connections through the CAN bus. Each inverter broadcasts its own device ID and status information through the CAN bus. Determine one inverter as the master inverter and configure the other inverters as slaves.

[0043] Battery array initialization: Each subgroup (16 groups in total) specifies a battery unit as the master, and configures the other battery units as slaves. The master battery unit sends an initialization signal to the slave battery unit via the 485 bus for self-identification and address setting. Each subgroup master broadcasts its own address and status information via the CAN bus.

[0044] Overall system synchronization: The master inverter sends a synchronization signal to all subgroup hosts to ensure that all battery units start working at the same time. After the subgroup host responds to the synchronization signal, it sends a synchronization command to the battery units in the subgroup.

[0045] b) Designate one battery unit in each subgroup as the master, and set the remaining battery units as slaves, and achieve communication between the master and the slaves through the 485 communication protocol; further, the master is selected based on a predefined position standard, which is the first battery unit in the subgroup.

[0046] Specifically, within each subgroup, one battery unit is designated as the master, and the remaining battery units are designated as slaves. The selection of the master is based on a predefined position standard, that is, the first battery unit in each subgroup is designated as the master. Data exchange between the master and the slave is achieved through the RS-485 communication protocol. In this way, the master is responsible for collecting data from all slaves in the subgroup, and integrating this data and transmitting it to a higher-level control center through the CAN communication protocol.

[0047] The main responsibilities of the host include:

[0048] Initialize the communication network within the subgroup;

[0049] Query slave status information, such as voltage, current, temperature, etc.;

[0050] Collect and summarize data from all slaves in the subgroup;

[0051] The aggregated data is sent to the superior control center via the CAN bus.

[0052] The main responsibility of the slave is to respond to the query request of the master and provide its own status information. The communication between the master and the slave follows a pre-defined protocol to ensure the accuracy and reliability of data transmission.

[0053] For example, within a subgroup, the host queries the status of each slave in sequence through the 485 bus. After receiving the query request, each slave returns its current voltage, current and other information. After the host collects the information of all slaves, it forms a data packet and transmits this information to the upper control system through the CAN bus.

[0054] This implementation can effectively simplify the communication logic within the subgroup while ensuring efficient data transmission. By setting the first battery unit as the host, communication delays or errors caused by uncertain position can also be avoided. In addition, such a configuration helps to achieve a modular design of the system, making it easy to expand and maintain.

[0055] c) Use the CAN communication protocol to establish communication connections between subgroups, and assign a unique identification address to each subgroup according to a pre-set address rule; further, the unique identification address between subgroups is set by a hardware dip switch.

[0056] Specifically, the battery array internal parallel strategy:

[0057] The basic strategy for paralleling in a battery pack is: the top battery is the master, and the remaining 15 batteries are slaves. When paralleling, the data is collected uniformly on the first master. Assume that the master-slave mode adopts the dial switch mode. Figure 3 As shown, 485 communication is adopted in the group, and the master and slave machines collect the data of 16 batteries through querying and then process them. Specific embodiments

[0059] Assume that there is a subgroup that contains 16 battery cells. During installation, the battery cell at the top is set as the master, and the remaining 15 battery cells are set as slaves. The specific settings of the dip switches can be adjusted according to actual conditions to ensure that only the selected master battery cell has master control authority.

[0060] Initialization phase:

[0061] After the hardware installation is complete, set the host according to the DIP switch. Only the top battery unit (i.e. the host) is set to active mode, and the other battery units remain in the default inactive mode.

[0062] The DIP switch settings are as follows: Figure 3 As shown, the dial code of the host should be set differently from other battery units to identify its special role.

[0063] Data collection phase:

[0064] After the host starts, it initiates a query request through the 485 bus to inquire about the status information of all slaves in the subgroup, including voltage, current, temperature, etc.

[0065] After receiving the query command from the host, each slave responds with its current status data.

[0066] The host collects the data from the slaves one by one and organizes and stores all the data.

[0067] Data processing stage:

[0068] The host processes the collected data, for example, calculating statistical data such as average value and maximum value.

[0069] The processed data is tagged and prepared for transmission to higher-level management systems via the CAN bus.

[0070] Data transmission phase:

[0071] The host reports the processed data to the upper control system through the CAN bus.

[0072] The upper-level control system can perform further analysis and decision-making based on this data, such as adjusting charging and discharging strategies or performing maintenance tasks.

[0073] d) The host periodically sends synchronization instructions to all subgroups, triggering the battery units in the subgroup to self-identify and set their respective address identifiers to complete the group parallel connection. Furthermore, the address setting of the battery units in the subgroup is carried out in the order in which the synchronization instructions are received.

[0074] In addition, the synchronization instruction contains a code for triggering the battery unit address setting, and the battery unit sets its own address identification in sequence according to the code sequence in the received instruction. The code is a predetermined instruction set used to instruct the battery unit to enter the address setting mode and automatically configure the address in the order of the received instructions, ensuring that each battery unit has a unique address identification for subsequent communication and management.

[0075] To describe how the battery cells set their address identifiers according to the code sequence in the received synchronization command, we can use an algorithmic formula to express this process. Assuming that we have N battery cells that need to be configured with addresses, and the synchronization command contains N unique codes, we can define the address setting algorithm through the following steps:

[0076] Initialize all battery units to standby state, waiting for synchronization instructions.

[0077] The synchronization instruction contains a unique code Ci (i∈[1,N]) for instructing the battery unit to enter the address setting mode.

[0078] When the battery unit receives the synchronization command, it identifies its position in the sequence based on the received Ci code.

[0079] Each battery cell sets its own address identifier Ai according to its own Ci, so that Ai=i.

[0080] The algorithm formula can be described as follows:

[0081] Assume S is a set of synchronization instructions, S = {C1, C2, ..., CN}, each Ci is a unique code used to trigger the corresponding battery unit to enter the address setting mode.

[0082] When battery cell j receives the synchronization command Ci, then:

[0083] i&\text{if}C_j=C_i\\A_j&\text{otherwise}\end{cases}\]Here \(A_j\) represents the address identifier of the battery cell \(j\).

[0084] When a battery cell \(j\) receives a synchronization instruction corresponding to \(C_i\), it will set its address identifier to \(i\), otherwise it will keep the original address identifier unchanged. In actual applications, the battery cell may receive synchronization instructions through a certain communication protocol, and determine whether to set the address by comparing the received code \(C_i\) with the pre-stored code. This process ensures that each battery cell has a unique address identifier, which facilitates management and communication.

[0085] Specifically, the strategy for parallel connection between battery array groups is as follows:

[0086] The basic strategy for paralleling battery groups is: the battery groups are divided into 0-15 or 16 groups from left to right. CAN communication is used between groups. The difficulty of paralleling between groups is how to determine the address of each group. The method to determine the address is to set the physical address of the first group host to 0-15, such as Figure 4 shown.

[0087] The DIP address of the entire battery array is as follows: Figure 5 As shown in the figure, when the groups are connected in parallel, the protocol stipulates that the host will send instructions every 1S:

[0088] 0x305:00-00-00-00-00-00-00-00

[0089] Once the slave (i.e. the first battery in the 16-group group) receives the 0x305 instruction, it will automatically change its address to 0000, and the first battery in each group will automatically complete the group parallel operation. At the same time, the first battery in the battery group that receives the 0x305 message will mark its address as 0, the second battery that receives the 0x305 message will mark its address as 1, and the last battery that receives the 0x305 message will mark its address as f.

[0090] After the data in each group is collected, the information reported by each group is distinguished by the frame ID. For example, 0x0351's 0 represents the 0th group of batteries, and 351 represents the frame for sending data; 0x1351's 1 represents the 1st group of batteries, and 351 represents the frame for sending data; 0x2351's 2 represents the 2nd group of batteries, and 351 represents the frame for sending data; 0x3351's 3 represents the 3rd group of batteries, and 351 represents the frame for sending data; and so on. 0xf351's f represents the 16th group of batteries, and 351 represents the frame for sending data. The actual results are as follows: Figure 6 shown.

[0091] In another embodiment, the above-mentioned method for grouping and paralleling energy storage battery groups further includes:

[0092] e) Collect the status information of all battery cells in the subgroup and process them centrally through the host;

[0093] f) The subgroup host sends the collected status information to the central control system via the CAN bus;

[0094] g) The central control system performs data analysis and management based on the received status information;

[0095] h) When the system detects any fault, it sends instructions to the corresponding subgroup host through the CAN bus to perform fault diagnosis or repair measures. Further, fault diagnosis includes but is not limited to short circuit detection and overheating protection measures. Fault detection: Each battery unit regularly reports voltage, current, temperature and other status information to the subgroup host. The subgroup host summarizes the information and reports to the main control inverter.

[0096] For example:

[0097] Assume that there are M subgroups in the system, and each subgroup has K battery cells. Each battery cell has a state information Sjk, where j represents the jth subgroup and k represents the kth battery cell in the subgroup.

[0098] Collect status information:

[0099] Each subgroup host is responsible for collecting the status information of all battery cells in its subgroup and sending this information to the central control system after aggregation. We can define a subgroup state vector Vj, which contains the status information of all battery cells in subgroup j, Vj = {Sj1, Sj2, ..., SjK}, j∈[1, M];

[0100] Send status information:

[0101] The subgroup host sends the status information Vj to the central control system via the CAN bus.

[0102] Data Analysis and Management:

[0103] The central control system receives the status information of all subgroups and performs data analysis and management. A global status matrix MS can be defined, which contains the status information of all subgroups:

[0104] S_{11}&S_{12}&\cdots&S_{1K}\\S_{21}&S_{22}&\cdots&S_{2K}\\\vdo ts&\vdots&\ddots&\vdots\\S_{M1}&S_{M2}&\cdots&S_{MK}\end{bmatr ix}\]The central control system can perform further data analysis and management based on the received status information \(M_S\), such as monitoring battery health status and optimizing charging strategies.

[0105] Algorithm flow description:

[0106] 1. **Collect status information**: The subgroup host \(j\) collects the status information \(S_{jk}\) of all battery cells in the subgroup \(j\) to form a state vector \(V_j\).

[0107] 2. **Send status information**: The subgroup host \(j\) sends the state vector \(V_j\) to the central control system through the CAN bus.

[0108] 3. **Data analysis and management**: The central control system receives the status information of all subgroups \(V_j\), builds the global state matrix \(M_S\), and analyzes and manages the data.

[0109] Fault response: When a battery unit is detected to be abnormal (such as overheating, abnormal voltage, etc.), the subgroup host immediately takes protective measures, such as disconnecting the battery unit from the system. The subgroup host reports the fault information to the main control inverter, which records the fault information and starts the fault recovery program. If it is a minor fault, try to recover by software reset; if it is a serious fault, isolate the faulty unit and notify maintenance personnel.

[0110] Maintaining and monitoring battery status

[0111] Real-time monitoring: The main control inverter receives status information from all sub-group hosts through the CAN bus and performs real-time monitoring. The monitoring software displays the status of each battery unit, including key indicators such as charge / discharge status, temperature, and voltage.

[0112] Preventive maintenance: Predict possible failures based on historical data and take measures in advance, such as replacing battery cells that are about to fail. Regularly check the connection of battery cells to ensure that there is no looseness or poor contact.

[0113] Status Report: The system generates a status report regularly, detailing the status of all battery cells, so that maintenance personnel can understand the system operation status. The report includes information such as health assessment, performance analysis, and recommended maintenance activities.

[0114] Through the above process, this embodiment provides an efficient and reliable method for grouping and paralleling energy storage systems, which ensures the normal operation of the system and facilitates system maintenance and fault handling.

[0115] The specific embodiments are as follows:

[0116] In a practical application scenario, suppose there is a battery array consisting of 16 groups of batteries, each with 16 battery cells. The top battery in each subgroup is the master, and the other 15 batteries are slaves. The master and slaves exchange data via the 485 communication protocol.

[0117] e) The host in the subgroup is responsible for collecting the status information of all slaves through the 485 bus, including but not limited to the voltage, current, temperature and other data of the battery unit. Once the collection is completed, the host integrates all the information into a data packet.

[0118] f) The host then sends the collected status information to the central control system via the CAN bus. The data packet here contains the status information of all battery cells in the subgroup, and the data of different subgroups are distinguished by the CAN ID identifier.

[0119] g) After receiving this information, the central control system will analyze and process it to determine whether the working status of the battery pack is normal. If it is found that the voltage fluctuation of a battery pack is too large or the temperature is too high, the central control system will record this information and may trigger an alarm or take preventive measures.

[0120] h) When the central control system detects any abnormal situation, such as a battery short circuit or overheating, it sends instructions to the corresponding sub-group host through the CAN bus, instructing it to perform fault diagnosis or take protective measures. For example, if a battery overheating is detected, the central control system may send a command to the host to disconnect the power supply of the battery unit to prevent safety issues caused by overheating. Similarly, if a short circuit is detected, the central control system may require the host to shut down the affected battery unit and start the backup unit to maintain the normal operation of the system.

[0121] Through such an implementation method, the system can effectively monitor and manage a large number of battery cells, ensuring the stability and safety of the energy storage system, while also improving the system's maintainability and user experience.

[0122] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for grouping and paralleling energy storage battery groups, characterized in that: The following steps are involved: a) dividing the battery pack array into a plurality of subgroups, each subgroup comprising a plurality of battery cells; b) Designate one battery unit in each subgroup as the master, and set the remaining battery units as slaves, and realize communication between the master and the slaves through the 485 communication protocol; c) Use the CAN communication protocol to establish communication connections between subgroups and assign a unique identification address to each subgroup according to a pre-set address rule; d) The host periodically sends synchronization instructions to all sub-groups, triggering the battery units in the sub-group to self-identify and set their respective address identifiers to complete the parallel connection within the group.

2. A method for grouping and paralleling energy storage battery groups according to claim 1, characterized in that: The method further comprises: e) Collect the status information of all battery cells in the subgroup and process them centrally through the host; f) The subgroup host sends the collected status information to the central control system via the CAN bus; g) The central control system performs data analysis and management based on the received status information.

3. A method for grouping and paralleling energy storage battery groups according to claim 2, characterized in that: The method further comprises: h) When the system detects any fault, it sends instructions to the corresponding subgroup host via the CAN bus to perform fault diagnosis or repair measures.

4. A method for grouping and paralleling energy storage battery groups according to claim 3, characterized in that: Fault diagnosis includes but is not limited to short circuit detection and overheating protection measures.

5. A method for grouping and paralleling energy storage battery groups according to claim 1, characterized in that: The subgroup division is performed according to the physical arrangement order of the battery array, and each subgroup contains the same number of battery cells.

6. A method for grouping and paralleling energy storage battery groups according to claim 1, characterized in that: The selection of the master is based on predefined position criteria and is the first battery cell in the subgroup.

7. A method for grouping and paralleling energy storage battery groups according to claim 1, characterized in that: The unique identification address between subgroups is set by hardware dip switches.

8. A method for grouping and paralleling energy storage battery groups according to claim 1, characterized in that: The address setting of the battery cells in the subgroup is carried out in the order in which the synchronization instructions are received.

9. A method for grouping and paralleling energy storage battery groups according to claim 8, characterized in that: The synchronization instruction includes a code for triggering the setting of the battery unit address, and the battery unit sets its own address identifier in sequence according to the code sequence in the received instruction.

10. A method for grouping and paralleling energy storage battery groups according to claim 9, characterized in that: The code is a predetermined set of instructions for instructing the battery unit to enter an address setting mode and automatically configure the address in the order in which the instructions are received.

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