A network construction method for an energy storage battery system and an energy storage battery system

Abstract

The application discloses a network construction method for an energy storage battery system and the energy storage battery system. The network construction method for the energy storage battery system comprises a new slave machine network access method. When the new slave machine is powered on, the communication address of the new slave machine is set as a unified preset default address, and the new slave machine is in an un-networked state. The master machine sends a network access invitation instruction to the slave machine with the preset default address. The slave machine in the un-networked state generates a random time delay after receiving the network access invitation instruction. If the random time delay arrives and no other slave machine sends a network access response, the slave machine sends a network access response message to the master machine and sets its own state as a quasi-networked state. After receiving the network access response message, the master machine sends an address allocation instruction to the slave machine with the preset default address. After receiving the address allocation instruction, the slave machine in the quasi-networked state modifies its own communication address from the preset default address to a target address.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a network construction method for an energy storage battery system and an energy storage battery system. Background Technology

[0002] In energy storage battery systems, multiple energy storage devices acting as slaves typically communicate with the master energy storage device via RS-485 bus and Modbus RTU protocol. This communication mode is a polling structure with a single master and multiple slaves. Specifically, only the master energy storage device can initiate communication, while slave energy storage devices only respond when the master queries them. Furthermore, when the master energy storage device broadcasts, no slave energy storage device may respond; otherwise, data corruption on the bus will occur.

[0003] However, in long-term unattended scenarios such as energy storage power stations, commercial and industrial energy storage cabinets, and containerized energy storage battery systems, the limitations of related technologies become increasingly apparent when facing demands such as battery module replacement, battery cluster expansion, master control failure switching, or grid connection of multiple pre-assembled network subsystems. For example, because the Modbus RTU protocol itself lacks a master election mechanism, once the energy storage device acting as the master goes offline or experiences a power failure, a new master energy storage device cannot be elected without human intervention, leading to the system losing its scheduling capabilities and becoming paralyzed. Furthermore, because the RS-485 bus is a half-duplex shared bus and lacks a conflict arbitration mechanism, when multiple independent pre-assembled network subsystems are connected to the same RS-485 bus, situations such as multiple masters coexisting, address conflicts, and communication chaos will arise.

[0004] Therefore, there is an urgent need for a network construction method to enable automatic grid connection of energy storage devices, automatic takeover of the main control system, and automatic network convergence in scenarios such as replacement, expansion, abnormal switching, or grid connection of multiple pre-built network subsystems, thereby ensuring the continuous and stable operation of the energy storage battery system. Summary of the Invention

[0005] One object of the present invention is to provide a network construction method for energy storage battery systems that can solve or alleviate at least one of the defects in the above-mentioned background art.

[0006] Another object of the present invention is to provide an energy storage battery system that can solve or alleviate at least one of the defects in the above-mentioned background art.

[0007] The first aspect of this invention provides a network construction method for an energy storage battery system, comprising: a new slave device joining the network method, wherein the new slave device, upon power-on, sets its own communication address to a unified preset default address and its own state to an unjoined state; the host periodically broadcasts a network joining invitation command to slave devices whose communication address is the preset default address; upon receiving the network joining invitation command, a slave device in the unjoined state generates a random delay and continuously listens to the bus during the random delay; if it detects that another slave device has sent a network joining response before the random delay arrives, it stops timing and remains in the unjoined state; if the random delay... If the delay arrives and no other slave device sends a network access response, the slave device sends a network access response message to the host and sets its own state to the pre-access state. After receiving the network access response message, the host sends an address allocation instruction to the slave device whose communication address is the preset default address. The address allocation instruction contains the target address. After receiving the address allocation instruction, the slave device in the pre-access state changes its own communication address from the preset default address to the target address and replies with an acknowledgment message to the host. Here, the new slave device refers to a newly added energy storage device acting as a slave device, and the host device refers to the energy storage device acting as the host device.

[0008] As a preferred embodiment, the network construction method for the energy storage battery system further includes a master election method. The master election method includes: during normal operation, the master broadcasts heartbeat packets at fixed intervals; slave devices maintain the master-slave relationship by monitoring the heartbeat packets; when a slave device does not receive the heartbeat packet within a preset timeout period, it determines that the master is offline and initiates a master election process; the master election process includes: the slave device calculates a waiting delay based on its current communication address and listens to the bus during the waiting delay; if it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and maintains its slave status; if the waiting delay arrives and it does not hear a heartbeat packet broadcast by another energy storage device, it broadcasts a heartbeat packet to other energy storage devices and becomes the new master; wherein, the new master refers to the newly promoted energy storage device as the master.

[0009] As a preferred embodiment, the heartbeat packet contains a list of member addresses of the current network; when the slave device becomes the new master device, it polls and confirms the communication addresses in the old heartbeat packet to obtain the new list of member addresses.

[0010] As a preferred embodiment, the network construction method for the energy storage battery system further includes a network merging method. The network merging method includes: when an energy storage device determines that the bus is chaotic, it automatically reverts to the preset default address and sets its own state to an unconnected state; the energy storage device calculates a waiting delay based on its previous communication address and listens to the bus during the waiting delay; if it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and remains in the unconnected state; if the waiting delay arrives and no heartbeat packet broadcast by another energy storage device is heard, it broadcasts a heartbeat packet to other energy storage devices and becomes a new host; wherein, the new host refers to the newly promoted energy storage device as a host.

[0011] As a preferred embodiment, when an energy storage device becomes a new host, it sends a network access invitation command to a slave device whose communication address is a preset default address. After receiving the network access invitation command, an energy storage device in an unconnected state calculates the response delay based on its previous communication address. When the response delay is reached, it sends a network access response message to the host and sets its own state to a pre-connection state. The host sends address allocation commands to other energy storage devices and establishes a new member table based on the order in which the network access response messages are received.

[0012] As a preferred embodiment, the energy storage device calculates a fixed delay based on its previous communication address, and then superimposes a fluctuating delay on the fixed delay to obtain the response delay.

[0013] As a preferred embodiment, the energy storage device calculates the base delay based on its previous communication address and superimposes a disturbance delay on the base delay to obtain the waiting delay.

[0014] As a preferred option, the waiting delay = previous communication address × first delay step + disturbance delay, where the range of values ​​for the disturbance delay is smaller than that for the first delay step; the response delay = previous communication address × second delay step + fluctuation delay, where the range of values ​​for the fluctuation delay is smaller than that for the second delay step.

[0015] As a preferred option, the preset default address is address 247 in the Modbus RTU protocol; slave devices in an unconnected state are only allowed to respond to the network access invitation command sent by the host.

[0016] A second aspect of the present invention provides an energy storage battery system, comprising: a plurality of energy storage devices connected by a bus, each of the energy storage devices being configured to perform the steps of the network construction method for the energy storage battery system as described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) After receiving the network access invitation instruction, the slave device generates a random delay and sends the network access response message after the random delay arrives. This reduces the probability of multiple slave devices sending network access response messages to the master device at the same time. (2) The slave continuously listens to the bus during the random delay period. When it hears that another slave has issued a network entry response, it stops timing and actively withdraws from the response competition. This setting helps to avoid message collisions even if there is a low probability of multiple slaves having the same or very similar random delay. This improves the reliability of the energy storage battery system. Attached Figure Description

[0018] Figure 1 This is a flowchart of a novel slave device network access method according to some embodiments of this application.

[0019] Figure 2 This is a flowchart of a host election method according to some embodiments of this application.

[0020] Figure 3 This is a flowchart of a network merging method according to some embodiments of this application. Detailed Implementation

[0021] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0024] A network construction method for an energy storage battery system includes: a method for adding new slave devices to the network, such as... Figure 1As shown, the method for a new slave device to join the network includes: when the new slave device powers on, it sets its own communication address to a unified preset default address and its own status to an unjoined state; the master periodically broadcasts a network joining invitation command to slave devices whose communication address is the preset default address; after receiving the network joining invitation command, a slave device in the unjoined state generates a random delay and continuously listens to the bus during the random delay. If it hears that another slave device has sent a network joining response before the random delay arrives, it stops timing and remains in the unjoined state; if the random delay arrives and no other slave device sends a network joining response, it sends a message to the master. The master device sends a network access response message and sets its status to pre-access state. Upon receiving the network access response message, the master device sends an address allocation command to the slave device whose communication address is the preset default address. This address allocation command includes the target address. Upon receiving the address allocation command, the slave device in pre-access state changes its communication address from the preset default address to the target address and replies with an acknowledgment message to the master device, thus entering normal slave status. Here, a new slave device refers to a newly added energy storage device acting as a slave, and a slave device refers to an energy storage device acting as a slave. The master device refers to an energy storage device acting as a master. The identity of an energy storage device includes both its slave status as a slave and its master status as a master.

[0025] It is understandable that after receiving the network access invitation command, the slave device generates a random delay and sends the network access response message only after the random delay has elapsed. This reduces the probability of multiple slave devices simultaneously sending network access response messages to the master, thus reducing the probability of message collisions and improving the stability and determinism of the energy storage battery system. Furthermore, the slave device continuously listens to the bus during the random delay. When it detects that another slave device has already sent a network access response, it stops timing and actively withdraws from the response competition. This configuration helps avoid message collisions even in the low-probability scenario where multiple slave devices have very similar random delays. In other words, in each round of the master's network access invitation cycle, at most only one new slave device completes network access, thereby improving the reliability and determinism of the energy storage battery system.

[0026] Furthermore, the host only needs to broadcast network access invitation commands and address allocation commands to the preset default address. Only slave devices in the pre-access state will change their communication addresses from the preset default address to the target address after receiving the address allocation command. This setting simplifies the host's working logic, helps avoid complex polling, and improves the network access efficiency and success rate of new slave devices. It is worth mentioning that the use of preset default addresses for all new slave devices also helps simplify the factory configuration of energy storage equipment.

[0027] In at least one embodiment, such as Figure 1As shown, if a slave device detects that another slave device has sent a network access response before the random delay arrives, it stops and resets the timer, remaining in the non-network access state. After receiving a new round of network access invitation instructions from the master device, it generates a random delay again and continuously listens to the bus during the random delay. This process is repeated until network access is completed, giving the energy storage battery system good scalability.

[0028] In some embodiments, the default address is preset to address 247 in the Modbus RTU protocol; slave devices in an unconnected state are only allowed to respond to network access invitation commands sent by the host.

[0029] It should be understood that the effective address range of the Modbus RTU protocol is 1 to 247, and address 247 is usually defined as a broadcast address or a reserved address. Specifying address 247 as the default address helps avoid conflicts with the normal addresses used for slave devices. In other words, this setting achieves logical isolation between the default address and the normal slave address, thereby helping to ensure that a new slave device will not interfere with the existing normal communication of the energy storage battery system after power-on. Those skilled in the art can also specify the default address according to the specific protocol of the energy storage battery system, and this application does not impose specific restrictions on this.

[0030] It is worth noting that, since slave devices in the un-networked state are only allowed to respond to network access invitation commands sent by the master, when the master broadcasts an address allocation command to the preset default address, only slave devices in the pre-networked state will change their communication address from the preset default address to the target address upon receiving the address allocation command. Slave devices in the un-networked state will not respond to the address allocation command, thus helping to ensure the uniqueness and determinism of the target address allocation. Furthermore, the fact that slave devices in the un-networked state are only allowed to respond to network access invitation commands sent by the master also helps to prevent abnormal network packets from interfering with new slave devices, thereby improving the stability and reliability of the energy storage battery system.

[0031] The energy storage device in this application can be implemented as a battery management unit, battery cluster control unit, energy management interface unit, battery box acquisition unit, temperature acquisition unit, or other unit with communication capabilities in an energy storage battery system.

[0032] The new slave-to-network access method described above facilitates automatic network access for energy storage devices during expansion or maintenance of energy storage battery systems. For example, a newly added slave battery management unit, upon power-up, can set its communication address to a preset default address and participate in network access competition according to the new method. Correspondingly, the master battery management unit broadcasts a network access invitation command to enable the new slave battery management unit to automatically connect to the network, thereby improving the scalability and deployment efficiency of the energy storage battery system. Similarly, the new slave-to-network access method described above is also applicable to battery cluster control units, energy management interface units, battery box acquisition units, temperature acquisition units, or other units with communication capabilities.

[0033] In some embodiments, the network construction method for an energy storage battery system further includes a host election method, such as... Figure 2 As shown, the master election method includes: the master broadcasts heartbeat packets at fixed intervals during normal operation; the slave maintains the master-slave relationship by monitoring heartbeat packets; when the slave does not receive a heartbeat packet within a preset timeout period, it determines that the master has gone offline and initiates the master election process; the master election process includes: the slave calculates the waiting delay based on its current communication address, and listens to the bus during the waiting delay; if it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and maintains its slave status; if the waiting delay arrives and it does not hear a heartbeat packet broadcast by another energy storage device, it broadcasts a heartbeat packet to other energy storage devices and becomes the new master; where, the new master refers to the newly promoted energy storage device as the master.

[0034] It should be understood that if a slave device does not receive a heartbeat packet within a preset timeout period, it determines that the master device is offline. This setting allows each slave device to identify the master device's offline status within a short time and helps avoid reliance on additional diagnostic messages. In at least one embodiment, the preset timeout period is 3 to 10 consecutive heartbeat cycles. This setting helps avoid misjudgments that could lead to unnecessary master device elections, thereby improving the stability of the energy storage battery system. Preferably, the preset timeout period is consistent across all energy storage devices.

[0035] Furthermore, such as Figure 2 As shown, after determining that the master has gone offline, the slave device calculates the waiting delay based on its current communication address and sends a heartbeat packet only after the waiting delay has elapsed. This reduces the risk of contention and conflict. In other words, each slave device calculates a different waiting delay based on its current communication address. Preferably, the slave device with the larger current communication address value calculates a longer waiting delay, thus staggering the response times of each slave device. Furthermore, this setting facilitates the slave device with the shortest waiting delay to broadcast the heartbeat packet first and become the new master, thereby shortening the master election time and improving the stability and reliability of the energy storage battery system.

[0036] In at least one embodiment, the waiting delay is calculated as: previous communication address × unit step size. It should be understood that by reasonably setting the unit step size, it helps to widen the interval between the waiting delays calculated by slave devices with similar current communication address values. For example, when the unit step size is 10ms, the waiting delay calculated by the slave device with current communication address 001 is 10ms, the waiting delay calculated by the slave device with current communication address 002 is 20ms, the waiting delay calculated by the slave device with current communication address 003 is 30ms, and so on. Those skilled in the art can also set the unit step size according to the specific circumstances of the energy storage battery system; this application does not impose specific limitations on this.

[0037] Furthermore, such as Figure 2 As shown, the slave device continuously listens to the bus during the waiting delay. When it detects a heartbeat packet broadcast by another energy storage device, it stops timing, actively withdraws from the master competition, and waits for confirmation from the new master. This confirmation could be a heartbeat packet broadcast by another slave device or a heartbeat packet broadcast by the previous master. This configuration helps avoid multiple rounds of voting or sending election messages, making the master selection process more efficient. Furthermore, slave devices that fail to become the new master retain their slave status and do not need to re-execute the aforementioned new slave network entry steps, thus shortening the time for network recovery.

[0038] In some embodiments, the heartbeat packet contains a list of member addresses of the current network. When a slave device becomes a new master, it polls for the communication addresses in the old heartbeat packet to obtain the new list of member addresses. After polling is complete, the newly promoted energy storage device as a master enters normal master status, while other energy storage devices as slaves remain normal slave status.

[0039] It is understandable that the master unit periodically broadcasts a list of member addresses to the slave units, enabling the slave units to maintain their master-slave relationship. In other words, the slave units can use the member address list to determine which energy storage devices in the energy storage battery system are acting as the master and which are acting as slaves. Furthermore, when a slave unit successfully elects itself as the new master unit, the new master unit actively polls other energy storage devices to confirm their communication address information, which helps prevent the loss of member address information due to the old master unit going offline. During the polling process, the new master unit can detect whether any energy storage devices have gone offline or whether new slave units (energy storage devices with the default communication address) have joined during the master election, thus quickly understanding the current status of the energy storage battery system. In addition, the new master unit obtains a new member list based on the polling results, which helps avoid the duplicate allocation of already occupied communication addresses.

[0040] For example, during the operation of an energy storage battery system, when the battery management unit (BMU) that was originally the master unit fails to connect, other BMUs that were originally slave units can participate in the master election based on their current communication addresses according to the master election method described above. This results in a newly elected master BMU without manual intervention, improving the self-healing efficiency of the energy storage battery system. In other words, it helps the energy storage battery system automatically restore the complete master-slave relationship without manual intervention, thereby improving the continuous operation capability of the energy storage battery system. Similarly, the master election method described above is also applicable to battery cluster control units, energy management interface units, battery box acquisition units, temperature acquisition units, or other units with communication capabilities.

[0041] In some embodiments, the network construction method for an energy storage battery system further includes a network merging method, such as... Figure 3 As shown, the network merging method includes: when an energy storage device determines that the bus is chaotic, it automatically reverts to a preset default address and sets its own status to an unconnected state; the energy storage device calculates the waiting delay based on its previous communication address and listens to the bus during the waiting delay; if it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and remains in the unconnected state; if the waiting delay arrives and it does not hear a heartbeat packet broadcast by another energy storage device, it broadcasts a heartbeat packet to other energy storage devices and becomes a new host; where a new host refers to a newly promoted energy storage device that acts as a host.

[0042] It is understandable that when the bus becomes chaotic, regardless of whether the energy storage device is currently acting as a master or a slave, it will automatically revert to the preset default address and set its status to an unconnected state. This will help to fundamentally eliminate the problems of multiple masters coexisting and duplicate communication addresses between slaves.

[0043] Furthermore, each energy storage device calculates its waiting delay based on its previous communication address and sends a heartbeat packet only after the waiting delay has elapsed. This reduces the risk of contention and conflicts. It also helps the energy storage device with the shortest waiting delay to broadcast its heartbeat packet first and become the new host, thereby shortening the network merging time and improving the stability and reliability of the energy storage battery system. It also helps to avoid communication paralysis caused by abnormal splitting or multiple hosts coexisting in the energy storage battery system, and helps to enable the energy storage battery system to automatically complete convergence without human intervention.

[0044] For example, when a pre-grouped network subsystem composed of multiple battery management units is connected in parallel to the same bus, the network merging method described above allows all battery management units to first revert to their default addresses. Then, through a waiting delay competition, a newly promoted battery management unit is selected as the master unit. This newly promoted master unit then re-completes the network entry and address allocation for other battery management units that are to be slave units, thereby achieving automatic convergence of the communication network of the energy storage battery system. Similarly, the network merging method described above is also applicable to battery cluster control units, energy management interface units, battery box acquisition units, temperature acquisition units, or other units with communication capabilities.

[0045] Bus disorder refers to the detection of multiple hosts in the energy storage battery system, or the need to connect multiple independent sub-networks to the same bus. Conditions for determining bus disorder include, but are not limited to: detecting N consecutive CRC check errors, detecting level conflicts for a duration exceeding a preset disorder duration, and failing to receive complete messages M consecutively. The values ​​of N and M can range from 3 to 10, and the preset disorder duration can range from 50ms to 200ms; this application does not impose specific limitations on these values.

[0046] In some embodiments, the energy storage device calculates the base delay based on its previous communication address and adds a disturbance delay to the base delay to obtain the waiting delay.

[0047] It is understandable that each energy storage device calculates a base latency of different lengths based on its previous communication address. Preferably, the energy storage device with a larger previous communication address value calculates a longer base latency, which helps to stagger the response times of each energy storage device. Furthermore, a disturbance latency is superimposed on the base latency. In this way, even if multiple energy storage devices with the same previous communication address exist when multiple sub-networks are merged, these energy storage devices with the same previous communication address may calculate the same base latency, but they can still calculate different waiting latencies due to the superimposed disturbance latency, thereby reducing the risk of contention conflicts.

[0048] Furthermore, the energy storage device continuously listens to the bus during the waiting delay period. When it detects that another energy storage device has broadcast a heartbeat packet, it actively withdraws from the host competition. This setting helps to avoid competition conflicts even in the low-probability situation where multiple energy storage devices have the same previous communication address and very similar disturbance delays.

[0049] It is worth mentioning that the above-mentioned network merging method has good adaptability to large-scale energy storage battery systems. Even if more than 100 energy storage devices participate in the merging at the same time, a unique new host can be selected in a relatively short period of time.

[0050] In at least one embodiment, the waiting delay = previous communication address × first delay step + disturbance delay, and the range of the disturbance delay is smaller than that of the first delay step.

[0051] It can be understood that the base delay = previous communication address × first delay step size. By reasonably setting the first delay step size, it helps to widen the interval between the base delays calculated by energy storage devices with similar previous communication address values. Furthermore, by making the range of disturbance delay values ​​smaller than the first delay step size, it helps to eliminate the competition uncertainty of energy storage devices with adjacent previous communication address values; in other words, it helps to ensure that the maximum value of the waiting delay calculated by the energy storage device with the previous communication address n is still less than the minimum value of the waiting delay calculated by the energy storage device with the previous communication address n+1, thereby helping to avoid competition conflicts and improving the stability and determinism of the energy storage battery system.

[0052] In at least one embodiment, the first delay step is 10ms. The base delay calculated by the energy storage device with the previous communication address 001 is 10ms, the base delay calculated by the energy storage device with the previous communication address 002 is 20ms, the base delay calculated by the energy storage device with the previous communication address 003 is 30ms, and so on. Further, the perturbation delay ranges from -4ms to 4ms, meaning the perturbation delay can be an integer between -4ms and 4ms. In this case, the range of the perturbation delay is 8ms, which is less than the first delay step of 10ms. For example, the waiting delay calculated by the energy storage device with the previous communication address 001 is 14ms, the waiting delay calculated by the energy storage device with the previous communication address 002 is 16ms, and the waiting delay calculated by the energy storage device with the previous communication address 003 is 32ms. Those skilled in the art can also set the range and accuracy of the first time delay step and the disturbance time delay according to the specific circumstances of the energy storage battery system, and this application does not impose specific restrictions on this.

[0053] In some embodiments, such as Figure 3 As shown, when an energy storage device becomes a new master, it sends a network access invitation command to the slave devices whose communication addresses are preset default addresses. Energy storage devices in an unconnected state, upon receiving the network access invitation command, calculate the response delay based on their previous communication addresses. If the response delay is reached, they send a network access response message to the master and set their status to pre-connection state. The master sends address allocation commands to other energy storage devices in the order they receive the network access response messages and establishes a new member table. After all address allocations are completed, the newly promoted master energy storage device enters normal master status, and the other slave energy storage devices enter normal slave status.

[0054] Furthermore, the energy storage device continuously monitors the bus during the response delay. If it detects that another energy storage device has sent a network access response before the response delay arrives, it stops and resets the timer, remaining in the non-network access state. After receiving a new round of network access invitation instructions from the host, it generates a new response delay or reuses the previously generated response delay, and continuously monitors the bus during the response delay. This process is repeated until network access is completed.

[0055] Alternatively, the energy storage device continuously monitors the bus during the response delay. If it detects that another energy storage device has sent a network access response before the response delay arrives, it stops timing and remains in an unconnected state. After receiving a new round of network access invitation instructions from the host, it continues timing on top of the original timing and continues to monitor the bus during the response delay. This process is repeated until network access is completed.

[0056] It is understandable that during network merging, there may be hundreds of energy storage devices in the energy storage battery system that are not connected to the network. In this embodiment, the energy storage devices that are not connected to the network calculate the response delay based on their previous communication addresses, which helps to reduce the probability that multiple energy storage devices will calculate the same response time to a large extent, thereby enabling multiple sub-networks to merge quickly and in an orderly manner.

[0057] It's worth noting that the host only needs to send network access invitation commands and address allocation commands to the preset default address. This simplifies the host's working logic, helps avoid complex polling, and improves the network access efficiency and success rate of energy storage devices. Furthermore, only energy storage devices in the pre-network access state will change their communication address from the preset default address to the target address after receiving the address allocation command, thus helping to ensure the uniqueness and determinism of the target address allocation.

[0058] In some embodiments, the energy storage device calculates a fixed delay based on its previous communication address and adds a fluctuating delay to the fixed delay to obtain a response delay.

[0059] It is understandable that each energy storage device calculates a fixed delay of different durations based on its previous communication address. Preferably, the energy storage device with a larger previous communication address value calculates a longer fixed delay, which helps to stagger the response time of each energy storage device. It also enables the network access response messages received by the host to be more evenly distributed on the time axis, thereby making the bus load smoother.

[0060] Furthermore, by superimposing a fluctuating delay on top of the fixed delay, even when multiple energy storage devices with the same communication address exist during the merging of multiple sub-networks, these devices, although calculating the same fixed delay, can also calculate different response delays due to the fluctuating delay. This reduces the probability of multiple energy storage devices simultaneously sending network access response messages to the host, thereby improving the stability and determinism of the energy storage battery system.

[0061] In at least one embodiment, the response delay = previous communication address × second delay step size + fluctuation delay, and the range of fluctuation delay is smaller than that of the second delay step size.

[0062] It can be understood that fixed delay = previous communication address × second delay step size. By reasonably setting the second delay step size, it helps to widen the interval between the fixed delays calculated by energy storage devices with similar previous communication address values. Furthermore, by making the range of fluctuating delay values ​​smaller than the second delay step size, it helps to eliminate the response uncertainty of energy storage devices with adjacent previous communication address values. In other words, it helps to ensure that the maximum value of the response delay calculated by the energy storage device with previous communication address n is still less than the minimum value of the response delay calculated by the energy storage device with previous communication address n+1. This reduces the probability of multiple energy storage devices simultaneously sending network access response messages to the host, i.e., it reduces the probability of message collisions, thereby improving the stability and determinism of the energy storage battery system.

[0063] In at least one embodiment, the second delay step is 10ms. The fixed delay calculated by the energy storage device with the previous communication address 001 is 10ms, the fixed delay calculated by the energy storage device with the previous communication address 002 is 20ms, the fixed delay calculated by the energy storage device with the previous communication address 003 is 30ms, and so on. Furthermore, the fluctuation delay ranges from -4ms to 4ms, meaning the fluctuation delay can be an integer between -4ms and 4ms. In this case, the fluctuation delay range spans 8ms. For example, the response delay calculated by the energy storage device with the previous communication address 001 is 14ms, the response delay calculated by the energy storage device with the previous communication address 002 is 16ms, and the response delay calculated by the energy storage device with the previous communication address 003 is 32ms. Those skilled in the art can also set the second delay step and the range and precision of the fluctuation delay according to the specific circumstances of the energy storage battery system; this application does not impose specific limitations on this.

[0064] It should be understood that the aforementioned host election method and network merging method only utilize the existing communication address information of the energy storage device, and the calculation of waiting delay and response delay is simple. Through the extension of the software protocol layer, the energy storage battery system can be endowed with self-healing and convergence capabilities, which helps to avoid adding additional backup hosts or hardware arbitration circuits, thereby reducing the overall cost of the energy storage battery system. It can also be compatible with existing energy storage battery systems that combine RS-485 bus and Modbus RTU protocol, thereby reducing the cost of modifying existing energy storage battery systems.

[0065] An energy storage battery system includes: a plurality of energy storage devices connected by a bus, each energy storage device being configured to perform the steps of the network construction method for the energy storage battery system described above, so that the energy storage battery system has good scalability, continuous operation capability and convergence capability.

[0066] The energy storage device can be implemented as a battery management unit, battery cluster control unit, energy management interface unit, battery box acquisition unit, temperature acquisition unit, or other units with communication capabilities within an energy storage battery system. Furthermore, the bus of the energy storage battery system can be implemented as a half-duplex shared bus such as RS-485, CAN, or LIN; this application does not impose specific limitations on this.

[0067] The basic principles, main features, and advantages of this invention have been described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection claimed by this invention is defined by the appended claims and their equivalents.

Claims

1. A network construction method for an energy storage battery system, characterized in that, include: A new method for slave devices to join the network, the method comprising: When a new slave device is powered on, it sets its own communication address to a unified preset default address and sets its own status to "not connected to the network". The host periodically broadcasts network access invitation commands to slave devices whose communication addresses are preset default addresses; After receiving the network access invitation command, the slave device in the non-network access state generates a random delay and continuously listens to the bus during the random delay. If it hears that another slave device has sent a network access response before the random delay arrives, it stops timing and remains in the non-network access state. If the random delay arrives and no other slave device sends a network access response, it sends a network access response message to the host and sets its own state to the pre-network access state. After receiving the network access response message, the host sends an address allocation instruction to the slave device whose communication address is a preset default address. The address allocation instruction includes the target address. After receiving the address allocation instruction, the slave device in the access network state modifies its own communication address from the preset default address to the target address and replies with an acknowledgment message to the host. The term "new slave device" refers to a newly added energy storage device that acts as a slave device, and the term "master device" refers to an energy storage device that acts as a master device.

2. The network construction method for an energy storage battery system according to claim 1, characterized in that, The network construction method for the energy storage battery system further includes a host election method, which includes... During normal operation, the host broadcasts heartbeat packets at fixed intervals; The slave device maintains the master-slave relationship by monitoring the heartbeat packet. When the slave device does not receive the heartbeat packet within a preset timeout period, it determines that the master is offline and starts the master election process. The host election process includes, The slave device calculates the waiting delay based on its current communication address and listens to the bus during the waiting delay. If it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and maintains its slave status. If the waiting delay arrives and it does not hear a heartbeat packet broadcast by another energy storage device, it broadcasts a heartbeat packet to the other energy storage device and becomes the new master. The new host refers to the newly promoted energy storage device that serves as the host.

3. The network construction method for an energy storage battery system according to claim 2, characterized in that, The heartbeat packet contains a list of member addresses in the current network; when the slave device becomes the new master device, it polls and confirms the communication addresses in the old heartbeat packet to obtain the new list of member addresses.

4. The network construction method for an energy storage battery system according to claim 1, characterized in that, The network construction method for energy storage battery systems further includes a network merging method, which includes... When the energy storage device determines that the bus is disordered, it automatically returns to the preset default address and sets its own status to an unconnected state. The energy storage device calculates the waiting delay based on its previous communication address and listens to the bus during the waiting delay. If it hears a heartbeat packet broadcast by another energy storage device before the waiting delay arrives, it stops timing and remains in an unconnected state. If the waiting delay arrives and it does not hear a heartbeat packet broadcast by another energy storage device, it broadcasts a heartbeat packet to other energy storage devices and becomes a new host. The new host refers to the newly promoted energy storage device that serves as the host.

5. The network construction method for an energy storage battery system according to claim 4, characterized in that, When the energy storage device becomes the new host, it sends a network access invitation command to the slave device whose communication address is the preset default address; After receiving the network access invitation instruction, the energy storage device in the non-network access state calculates the response delay based on its previous communication address. When the response delay is reached, it sends a network access response message to the host and sets its own state to the pre-network access state. The host sends address allocation instructions to other energy storage devices and establishes a new member table based on the order in which the network access response messages are received.

6. The network construction method for an energy storage battery system according to claim 5, characterized in that, The energy storage device calculates a fixed delay based on its previous communication address, and then adds a fluctuating delay to the fixed delay to obtain the response delay.

7. The network construction method for an energy storage battery system according to claim 4, characterized in that, The energy storage device calculates the base delay based on its previous communication address, and adds a disturbance delay to the base delay to obtain the waiting delay.

8. The network construction method for an energy storage battery system according to any one of claims 6-7, characterized in that, Waiting delay = previous communication address × first delay step + disturbance delay, the range of disturbance delay is smaller than the range of the first delay step; Response delay = previous communication address × second delay step + fluctuation delay, the range of fluctuation delay is smaller than the range of the second delay step.

9. The network construction method for an energy storage battery system according to any one of claims 1-7, characterized in that, The preset default address is address 247 in the Modbus RTU protocol; slave devices in an unconnected state are only allowed to respond to the network access invitation command sent by the host.

10. An energy storage battery system, characterized in that, include: Multiple energy storage devices connected via a bus, each of which is configured to perform the steps of the network construction method for an energy storage battery system as described in any one of claims 1-9.

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