Battery pack parallel connection control method, battery management system and household energy storage system

Abstract

The application provides a battery pack parallel control method, a battery management system and a household energy storage system. The control method comprises the following steps: reading the dial switch setting on the battery pack; the host in the battery pack sends information to each slave; when it is determined that there is a slave online, the host requests the energy storage converter to pre-charge the host and the slave in the online state, and enters a normal charging mode after completing the pre-charge, and detects the host-slave fault condition; when it is determined that there is no slave online, the host requests the energy storage converter to charge the host, and detects the host fault condition. The application has an emergency response mechanism, can take action quickly according to the difference between the single-machine and parallel-machine states when detecting abnormal conditions, first executes the protection mechanism of itself, and then executes corresponding operations according to the identified fault category, thereby greatly reducing the influence on the whole system.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a battery pack parallel control method, a battery management system, and a residential energy storage system. Background Technology

[0002] With the development of renewable energy, more and more households are adopting energy storage systems to store excess electricity for use when needed. Residential energy storage systems typically consist of multiple battery packs, which can operate independently or in parallel. To enable these battery packs to work collaboratively, an effective control system is essential to manage and coordinate their behavior. This includes, but is not limited to, assigning a unique identifier to each battery pack, monitoring the status of each pack, and handling data exchange between them. Current technologies lack effective emergency response mechanisms and cannot quickly take action, such as current limiting or disconnection, when anomalies are detected, thus failing to minimize the impact on the entire system. Summary of the Invention

[0003] The main objective of this invention is to propose a battery pack parallel control method, a battery management system, and a residential energy storage system, aiming to solve the problem that traditional residential energy storage systems lack an effective emergency response mechanism and cannot take rapid action, such as current limiting or disconnection, when abnormal conditions are detected, thereby minimizing the impact on the entire system.

[0004] This invention provides a battery pack parallel control method for residential energy storage systems. The energy storage system includes an energy storage converter and multiple parallel battery packs, each battery pack being equipped with a DIP switch. The control method includes:

[0005] Read the DIP switch settings on the battery pack to determine the master / slave status of the battery pack itself;

[0006] After determining the master and slave identities of the battery pack, the master in the battery pack sends information to each slave to confirm the online status of each slave.

[0007] When a slave device is found to be online, the master device requests the energy storage converter to precharge the master device and the online slave device. After the precharging is completed, the master device enters the normal charging mode and detects the master and slave device faults. When a fault is detected in either the master or slave device, the fault type of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault type.

[0008] When it is determined that no slave device is online, the master device requests the energy storage converter to charge the master device and detects the master device fault status. When a master device fault is detected, the master device fault type is identified and corresponding operations are performed according to the identified fault type.

[0009] Optionally, the control method further includes:

[0010] The master and slave devices enter a discharge mode and detect master and slave device faults. When a fault is detected in either the master or slave device, the fault type of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault type.

[0011] Optionally, the specific steps of detecting master-slave faults, identifying the fault type of the master or slave when a fault is detected, and performing corresponding operations based on the identified fault type, include:

[0012] When a host failure is detected, the host protection mechanism is activated to identify the host failure type and perform corresponding operations based on the identified failure type.

[0013] When a fault is detected in the slave device, the faulty slave device activates its own protection mechanism and sends fault information to the master device. The master device receives the fault information sent by the faulty slave device, identifies the fault type of the slave device, and performs corresponding operations according to the identified fault type.

[0014] Optionally, the specific steps of performing the corresponding operation based on the identified fault category include:

[0015] The host computer performs corresponding operations according to the identified fault category and a pre-set program.

[0016] Based on the corresponding operations performed according to the pre-set program, the host sends a request message to the energy storage converter, so that the energy storage converter receives the request message sent by the host and adjusts the charging / discharging current accordingly.

[0017] Optionally, the specific steps of the master in the battery pack sending information to each slave after determining the master-slave identity of the battery pack to confirm the online status of each slave include:

[0018] Based on the determination of the master and slave identities of the battery pack, parallel operation information is sent to the slave, so that the online slave can receive and respond to the master's broadcast frame;

[0019] The online status of the battery pack is determined by whether or not feedback information is received from the slave device in response to the master device's broadcast frame.

[0020] Optionally, the step of determining that a slave device is online specifically includes:

[0021] Upon receiving feedback information from the slave device's broadcast frame in response to the master device, the slave device is confirmed to be online.

[0022] Optionally, each battery pack is provided with a terminating resistor, the host computer is communicatively connected to a host computer, and the host computer is communicatively connected to slave devices sequentially according to the set numbers of the DIP switches. The control method further includes:

[0023] Based on confirming the online status of the slave device, the last slave device among the currently online slave devices is identified by reading the number of the DIP switch;

[0024] The terminating resistor of the host itself is turned on, and the terminating resistor of the control terminal slave is turned on.

[0025] Optionally, a current-limiting loop is provided in the battery pack compartment, and the control method further includes:

[0026] When a slave device is detected online, the current in the battery pack is monitored. If the current in the battery pack exceeds a set threshold, the switch in the current limiting circuit is turned on to reduce the current in the battery pack.

[0027] The present invention also proposes a battery management system, including a memory and a processor, wherein the memory stores an application program, and the processor is used to run the application program in the memory to perform the steps of the battery pack parallel control method described above.

[0028] The present invention also proposes a residential energy storage system, including multiple battery packs, an energy storage converter, a host computer, and a battery management system as described above;

[0029] The battery pack includes a master unit and multiple slave units. The master unit is communicatively connected to a host computer, and the master unit and slave units communicate with each other and with each other via RS-485 cables.

[0030] This invention proposes a parallel control method for battery packs, featuring an emergency response mechanism. Upon detecting an anomaly, it can quickly take action based on whether the device is operating alone or in parallel mode. First, it executes its own protection mechanism, and then performs corresponding operations according to the identified fault category, thereby minimizing the impact on the entire system. Simultaneously, this control method uses a DIP switch to set the master / slave roles of the devices, ensuring that the slave device only interacts with the master, preventing communication failures between the master and slave devices. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0032] Figure 1This is a flowchart illustrating the steps of a battery pack parallel control method according to the present invention.

[0033] Figure 2 This is a table of single-unit / parallel SOP current reduction strategies for a battery pack parallel control method according to the present invention;

[0034] Figure 3 This is a flowchart illustrating the steps of an embodiment of the battery pack parallel control method of the present invention;

[0035] Figure 4 This is a circuit diagram of a limiting loop for a battery pack parallel control method according to the present invention;

[0036] Figure 5 This is a diagram of a DIP switch for a battery pack parallel control method according to the present invention.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0042] This invention provides a battery pack parallel control method for residential energy storage systems. The energy storage system includes an energy storage converter and multiple parallel-connected battery packs, each battery pack being equipped with a DIP switch, such as... Figure 1 As shown, the control method includes:

[0043] S100: Read the DIP switch settings on the battery pack to determine the master / slave identity of the battery pack itself;

[0044] S200: After determining the master and slave identities of the battery pack, the master in the battery pack sends information to each slave to confirm the online status of each slave;

[0045] S300: When it is determined that there is a slave device online, the master requests the energy storage converter to precharge the master and the slave device that is online, and after the precharging is completed, it enters the normal charging mode and detects the master and slave device fault conditions. When a fault is detected in either the master or slave device, the fault category of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault category.

[0046] S400: When it is determined that no slave device is online, the master device requests the energy storage converter to charge the master device and detects the master device fault condition. When a master device fault is detected, the master device fault type is identified and corresponding operations are performed according to the identified fault type.

[0047] More specifically, with the development of renewable energy, more and more households are adopting energy storage systems to store excess electricity for use when needed. Residential energy storage systems typically consist of multiple battery packs, which can operate independently or in parallel. To enable these battery packs to work collaboratively, an effective control system is essential to manage and coordinate their behavior. This includes, but is not limited to, assigning a unique identifier to each battery pack, monitoring the status of each pack, and handling data exchange between them. The reliability and efficiency of an energy storage system directly affect the user experience and the system's economic benefits; therefore, developing an efficient and stable parallel control strategy is crucial for improving the overall performance of energy storage systems.

[0048] Currently, in the case of a failure in a parallel battery pack control system, the system needs to be able to promptly notify the power conversion system (PCS) to perform the corresponding state of power (SOP) current limiting operation to ensure system stability.

[0049] Therefore, this application proposes a battery pack parallel control method to address the problem that traditional residential energy storage systems lack an effective emergency response mechanism and cannot take rapid action, such as current limiting or disconnection, when abnormal conditions are detected, thereby minimizing the impact on the entire system.

[0050] In step S100, the DIP switch settings on the battery pack are read to determine the master / slave status of each battery pack. Each battery pack should be equipped with a DIP switch used to set the master / slave address. The control system first reads the settings of these DIP switches upon startup to determine the role of each battery pack. It is crucial to ensure the DIP switch settings are correct, as incorrect settings may cause system malfunction or communication conflicts. Figure 5 The DIP switch table shown represents the master address (0) and the slave addresses (the others). Each BMS can be a master, but each system has only one master. It is necessary to ensure that the master and slave addresses are correctly assigned.

[0051] Specifically, each battery pack is equipped with an RS485-1 interface, an RS485-2 interface, an RS232 interface, a current-limiting circuit, and a terminating resistor. After determining the master and slave units of the battery pack, the master unit needs to connect to the host computer via the RS232 interface. After connecting to the host computer, the maximum SOP and the number of parallel units need to be configured. Configuring the maximum SOP involves setting the operating parameters of the battery system, while configuring the number of parallel units determines the number of slave units that can be connected to the system. Communication between the master and slave units, and between slave units themselves, is via the RS485-2 interface. Through the RS485-2 interface, the master unit can poll and read slave unit data, responsible for real-time monitoring of the status of all slave units, including but not limited to key parameters such as voltage, current, and temperature. Additionally, the master unit communicates with the PCS via the RS485-1 interface.

[0052] In step S200, after determining the master and slave identities of the battery pack, the master unit in the battery pack sends information to each slave unit to confirm their online status. Once the master unit has confirmed its identity, it sends an online status query request to all slave units via a communication link (such as RS485). Upon receiving the query request, the slave unit should immediately reply to the master unit to confirm its online status. Ensuring the stability and reliability of the communication link is crucial to avoid misjudgments of slave unit status due to communication failures.

[0053] The system needs to determine the number of slave devices currently online based on the communication between the master and slave devices. If only the master is online, the system will operate normally according to the no-parallel-connection logic and execute the operating procedures applicable to a single machine (including single-machine fault handling); if there are slave devices online, the system will enter the pre-charge operation phase.

[0054] Simultaneously with this step, the host also activates its own terminating resistor, and after determining the online status of the slave devices, the host, in conjunction with the DIP switch, identifies the last slave device currently online and controls its terminating resistor to activate. In a communication link, the terminating resistor is used to absorb reflected waves on the signal line, improving the stability and accuracy of signal transmission. The host activating its own terminating resistor ensures signal integrity during communication with the slave devices; the host, by reading the DIP switch settings or receiving the slave device's online status response, and considering the communication link topology, identifies the last slave device currently online and sends a command to it, requesting it to activate its built-in terminating resistor.

[0055] In step S300, when it is determined that a slave device is online, the master device requests the energy storage converter (PCS) to precharge the master device and the online slave device, and after the precharging is completed, it enters the normal charging mode and detects master and slave device fault conditions.

[0056] To protect the battery pack from current surges, the host computer performs a pre-charge operation before requesting the PCS to charge the battery pack. Pre-charging typically involves connecting the battery pack to the PCS with a small resistor to limit the initial charging current. After pre-charging is complete, both the host and slave computers enter normal charging mode, where the PCS charges the battery pack with an appropriate current and voltage. Specifically, the main purpose of the pre-charge operation is to slowly charge the battery through a small resistor (pre-charge resistor) before officially connecting to mains power, thereby limiting the current and preventing damage to the battery and circuit components from sudden high current surges.

[0057] When the system detects a slave device online, it first closes the pre-charge relay. The pre-charge relay, connected between the pre-charge resistor and the battery, controls the start and end of the pre-charge process. Simultaneously, the system disconnects the negative relay. The negative relay is typically connected between the battery's negative terminal and other parts of the circuit. Disconnecting the negative relay prevents current from flowing directly through the battery and circuit components during pre-charge, thus protecting them from sudden surges in current.

[0058] With the pre-charge relay closed and the negative relay open, current will slowly charge the battery through the pre-charge resistor. This process will continue for a period of time until the battery voltage gradually rises to near the system's operating voltage. Once the pre-charge process is complete, the system will disconnect the pre-charge relay. This marks the end of the pre-charge phase and prepares the system for normal operation. After disconnecting the pre-charge relay, the system will close the negative relay. In this way, the battery can connect to the rest of the system through the normal circuit path and begin normal operation.

[0059] During charging, both the host and slave devices continuously monitor their respective operating status, including parameters such as voltage, current, and temperature. Once an abnormality is detected, the system will immediately identify the fault type (such as overcharge, over-discharge, short circuit, etc.) and execute corresponding protection measures (such as cutting off the charging circuit and issuing an alarm).

[0060] In step S400, when no slave device is online, the master device requests the energy storage converter to charge the master device and detects master device faults. If no slave device is online, the master device will directly enter the charging mode without performing a pre-charging operation (because only the master device's battery pack needs charging at this time). In single-master charging mode, the master device also needs to continuously monitor its own operating status and implement corresponding protection measures when a fault is detected.

[0061] It is worth noting that steps S300 and S400 are parallel steps, and either a slave device is online or no slave device is online can occur. Regardless of whether the master or slave device fails, the self-protection mechanism is activated first to ensure that measures can be taken quickly to prevent the fault from spreading, protect other parts of the system from damage, and minimize the impact on users when a device failure occurs. The self-protection mechanism includes fault isolation, safe shutdown, and alarm notification.

[0062] In this application, after receiving a fault message, the host will perform corresponding flow reduction operations according to the pre-set single-machine / parallel SOP flow reduction strategy table. For example... Figure 2 As shown, the detailed single-machine / parallel SOP current reduction strategy table is as follows:

[0063] When the voltage exceeds the range, current reduction is applied in both single-unit and parallel operation scenarios.

[0064] When an alarm-type current limiting fault occurs, the current is reduced or the machine is stopped in standalone mode, and the current is reduced or the machine is stopped in parallel mode.

[0065] When a protection-type current limiting fault occurs, in standalone mode, when charging overcurrent protection current limiting occurs, both software and hardware simultaneously limit the current; in other cases of protection-type current limiting faults, the machine shuts down. In parallel mode, when charging overcurrent protection current limiting occurs, both software and hardware simultaneously limit the current; in other cases of protection-type current limiting faults, the slave unit with the fault shuts down, and the total current is reduced by the number of faulty units multiplied by the rated current.

[0066] In the parallel operation SOP current reduction strategy table, when multiple faults are triggered, to ensure voltage consistency between parallel operations, the number of parallel operations and the parallel operation SOP enable are set through the host computer, and the charging and discharging current is required not to exceed the battery's rated current.

[0067] This invention proposes a parallel control method for battery packs, featuring an emergency response mechanism. Upon detecting an anomaly, the system automatically selects the most appropriate protection mechanism based on whether the system is operating in standalone or parallel mode. For example, in standalone mode, it might directly cut off the power to prevent further damage, while in parallel mode, it might attempt to maintain system stability by adjusting the output of other parallel battery packs. This rapid action first executes its own protection mechanism, then performs corresponding operations based on the identified fault category, thereby minimizing the impact on the entire system. Simultaneously, this control method uses a DIP switch to set the master / slave roles of the devices, ensuring that the slave device only interacts with the master, preventing communication failures between the master and slave devices.

[0068] In one embodiment, the control method further includes:

[0069] The master and slave devices enter a discharge mode and detect master and slave device faults. When a fault is detected in either the master or slave device, the fault type of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault type.

[0070] When the energy storage system needs to supply power to an external load, the master and slave units will enter discharge mode according to system instructions or preset conditions. In discharge mode, the battery pack releases its stored electrical energy, which is converted into electrical energy suitable for the load through a power storage converter (PCS). During discharge, the master and slave units continuously monitor their respective operating status, including key parameters such as voltage, current, and temperature. Changes in these parameters reflect the health and performance status of the battery pack. Once abnormal parameters or trends are detected, the system will immediately trigger a fault detection mechanism. Based on the identified fault category, the system will implement corresponding protection measures to prevent the fault from worsening or spreading. For over-discharge faults, the system may immediately disconnect the discharge circuit to prevent the battery pack from being damaged by excessive discharge.

[0071] In one embodiment, the specific steps of detecting master-slave faults, identifying the fault type of the master or slave when a fault is detected, and performing corresponding operations based on the identified fault type include:

[0072] When a fault is detected in the host, the host protection mechanism is activated to identify the fault type and perform corresponding operations based on the identified fault type. When a fault is detected in the slave, the faulty slave activates its own protection mechanism and sends fault information to the host. The host receives the fault information sent by the faulty slave, identifies the fault type of the slave, and performs corresponding operations based on the identified fault type.

[0073] The identified fault categories include voltage exceeding range, alarm-related current limiting, and protection-related current limiting. Based on the identified fault category, the host executes preset response measures. (Refer to...) Figure 2 For faults exceeding the voltage range, the host may adjust the output voltage or activate the overvoltage protection mechanism. For alarm-type current limiting, the host will send an alarm message to the PCS or limit the current usage of some services to prevent fault escalation. For protection-type current limiting, the host will immediately cut off the power to the faulty section to protect other parts of the system from damage.

[0074] In one embodiment, the specific steps of performing the corresponding operation based on the identified fault category include:

[0075] The host performs corresponding operations according to the identified fault category and a pre-set program. Based on the corresponding operations performed according to the pre-set program, the host sends a request message to the energy storage converter so that the energy storage converter receives the request message and adjusts the charging / discharging current according to the request message sent by the host.

[0076] The host system, through its built-in monitoring and diagnostic system, can detect fault occurrences in real time and accurately identify the specific type of fault. Once the fault type is determined, the host will execute corresponding operations according to pre-set procedures or strategies. These pre-set procedures may cover various fault scenarios and corresponding countermeasures. As part of the countermeasures, the host will generate corresponding request information based on the current impact of the fault and the actual needs of the system, and send it to the energy storage converter via the communication interface.

[0077] The energy storage converter has communication capabilities, enabling it to receive request information from the host in real time. Upon receiving the request, the energy storage converter parses it to understand the specific operation the host wants it to perform, namely, adjusting the charging or discharging current. Based on the parsed request information, the energy storage converter adjusts its internal power conversion logic, thereby changing the charging or discharging current. This adjustment aims to ensure stable system operation or mitigate the impact of faults on the system.

[0078] According to the aforementioned single / parallel SOP current reduction strategy table, the host sends a request message to the energy storage converter, so that the energy storage converter receives and adjusts the charging / discharging current according to the request message sent by the host. The host sends the reduced SOP to the PCS, and the PCS will perform the current reduction operation according to the received SOP to ensure that the battery system can operate safely in the event of a fault.

[0079] In one embodiment, the specific steps of the master in the battery pack sending information to each slave after determining the master-slave identity of the battery pack to confirm the online status of each slave include:

[0080] Based on the established master / slave identities of the battery pack, a parallel connection message is sent to the slave devices, enabling online slave devices to receive and respond to the master's broadcast frame. Prior to this step, the system has already determined which device in the battery pack is the master and which is the slave by reading the DIP switch settings. Once the master / slave identities are confirmed, the master sends a broadcast frame containing parallel connection information to all slave devices, informing them that the master is ready for subsequent communication and status confirmation. A broadcast frame is a special communication frame used to send information to all slave devices without needing to know the specific address of each slave.

[0081] The online status of the battery pack is determined by whether or not feedback information is received from the slave devices responding to the master's broadcast frame. Online slave devices will receive broadcast frames from the master. Upon receiving a broadcast frame, the slave will send feedback information to the master according to a preset protocol or rules. This feedback information typically includes the slave's identity information and status information, informing the master that the slave is online and can communicate normally. After sending the broadcast frame, the master will wait for a period of time to receive feedback information from the slaves. During this time, the master will continuously monitor the communication channel to detect whether any slave has sent feedback information. Based on the received feedback information, the master can determine which slaves are online. If no feedback information is received from a particular slave, the master may assume that the slave is offline or faulty. The master will record the online status of each slave and take further action as needed. If an offline or faulty slave is detected, the master may activate corresponding protection mechanisms, such as alarms, logging, or attempting to re-establish communication.

[0082] In one embodiment, the step of determining that a slave device is online specifically includes:

[0083] Upon receiving feedback from a slave device responding to a broadcast frame from the master, the master confirms that the slave device is currently online. An online slave device will receive the master's broadcast frame and, according to a pre-defined communication protocol or rules, send feedback information to the master. This feedback information typically contains the slave device's identity information, used to confirm the slave device's identity and online status. When the master receives the slave device's feedback information, it immediately confirms that the slave device is online. This is because receiving the feedback information directly proves that the slave device can receive the master's broadcast frame and can communicate normally. Once the slave device is confirmed to be online, the master will record this status and may take further action as needed. For example, the master may update the system's status information, send notifications to users, or adjust the system's operating mode based on the number of online slave devices.

[0084] In one embodiment, such as Figure 3 As shown, each battery pack is equipped with a terminating resistor. The host computer is communicatively connected to the host computer, and the host computer is sequentially communicatively connected to the slave computer according to the set numbers of the DIP switches. The control method further includes:

[0085] S510: Based on confirming the online status of the slave device, the last slave device among the currently online slave devices is identified by reading the number of the DIP switch;

[0086] S520: The terminating resistor of the host itself is turned on, and the terminating resistor of the control terminal slave is turned on.

[0087] In step S510, based on confirming the online status of the slave devices, the DIP switch numbers are read. Each slave device has a DIP switch used to set its unique number or address. The host sequentially reads the DIP switch number of each online slave device via the communication connection; the slave device DIP switch numbers are 1 to 15. Based on the set numbers of the DIP switches, the host can identify the last online slave device, i.e., the end slave device. This is achieved by comparing the numbers of all online slave devices; the slave device with the largest number is considered the end slave device. For example, if the online slave device numbers are 1, 7, and 12, then the slave device with number 12 is the end slave device.

[0088] In step S520, after identifying the end slave device, the master device first turns on its own terminating resistor. Terminating resistors are typically used at the end of communication lines to provide proper impedance matching and reduce signal reflection and interference. Next, the master device sends a control command to the end slave device, requesting it to turn on its own terminating resistor. Upon receiving the command, the end slave device executes the corresponding operation and turns on its terminating resistor.

[0089] RS-485 communication is a type of bus communication, with its physical layer interface signals being RS-485A / 485B. Devices requiring communication connect their respective RS-485 communication networks to the RS-485A / 485B bus. When multiple devices communicate with each other, a terminating resistor needs to be connected in parallel between the RS-485A / 485B signals of the first and last devices to ensure stable communication. Most systems rely on fixed terminating resistor configurations. While this method is simple, it requires manual installation of the matching resistor, significantly increasing the risk of errors during field installation. This application employs a dynamic terminating resistor control mechanism, automatically adjusting the terminating resistor according to the actual conditions of the communication network, reducing human intervention and improving system reliability and maintenance convenience.

[0090] In one embodiment, such as Figure 4 As shown, a current-limiting loop is provided in the battery pack compartment, and the control method further includes:

[0091] When a slave device is detected online, the current in the battery pack is monitored. If the current in the battery pack exceeds a set threshold, the switch in the current limiting circuit is turned on to reduce the current in the battery pack. Figure 4 As shown, multiple battery packs are connected to the load, and a switch is installed between the battery packs and the load. By controlling the switch in the current-limiting loop, the circulating current is reduced and brought back to a safe range. The current-limiting loop does not stop working after a single adjustment but continuously monitors current changes and dynamically adjusts the current-limiting intensity based on real-time data. This closed-loop control mechanism ensures that the system maintains stable operation under various operating conditions.

[0092] Through a current-limiting circuit, the battery pack parallel system can operate smoothly even under large voltage differences, reducing reliance on battery pack voltage consistency. By dynamically controlling the circulating current, the system can reduce voltage instability caused by current fluctuations, improving overall operational reliability. By reducing the impact of circulating current on the battery pack, the system can effectively reduce the risk of battery overheating or overcharging / over-discharging, extending battery life. The current-limiting circuit can effectively prevent short circuits or thermal runaway caused by excessive circulating current, improving system safety.

[0093] This invention also proposes a battery management system, including a memory and a processor. The memory stores an application program, and the processor runs the application program in the memory to execute the steps of the battery pack parallel control method described above. The battery pack parallel control method has an emergency response mechanism that can quickly take action based on the difference between single-unit and parallel operation states when an abnormality is detected. First, it executes its own protection mechanism, and then performs corresponding operations according to the identified fault category, thereby minimizing the impact on the entire system.

[0094] This invention also proposes a residential energy storage system, including multiple battery packs, an energy storage converter, a host computer, and a battery management system as described above. Each battery pack includes a master unit and multiple slave units. The master unit is communicatively connected to the host computer, and communication between the master unit and slave units, as well as between slave units themselves, is achieved via RS-485 cables. This application uses DIP switches to define the master and slave unit identities, and specifies that the master unit interacts with the PCS and the host computer, while the slave units only interact with the master unit. Furthermore, a current-limiting loop protects the system during parallel operation to prevent excessive circulating current. Simultaneously, the system also incorporates a termination resistor control mechanism for the RS-485 communication line to ensure communication stability and reliability. Finally, when any abnormal situation is detected, the system executes its own protection logic and uploads the parallel operation standard operating procedure (SOP) to the PCS via the master unit for current limiting, ensuring the safe operation of the system.

[0095] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A battery pack parallel control method, applied to a residential energy storage system, the energy storage system comprising an energy storage converter and multiple parallel-connected battery packs, characterized in that, Each battery pack is equipped with a DIP switch and a terminating resistor, and a current-limiting loop is provided between the battery packs. The control method includes: Read the DIP switch settings on the battery pack to determine the master / slave status of the battery pack itself; After determining the master and slave identities of the battery pack, the master in the battery pack sends information to each slave to confirm the online status of each slave; the master communicates with the host computer, and the master and slaves communicate sequentially according to the set numbers of the DIP switch. Based on confirming the online status of the slave device, the end slave device among the currently online slave devices is identified by reading the number of the DIP switch; the host device's own terminating resistor is turned on, and the terminating resistor of the end slave device is also turned on. When a slave device is found to be online, the master device requests the energy storage converter to precharge the master device and the online slave device. After the precharging is completed, it enters the normal charging mode and detects the current between the battery packs. When the current between the battery packs exceeds a set threshold, the switch in the current limiting circuit is turned on to reduce the current between the battery packs. At the same time, the master and slave device fault conditions are detected so that when a fault is detected in either the master or slave device, the fault type of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault type. When it is determined that no slave device is online, the master device requests the energy storage converter to charge the master device and detects the master device fault status. When a master device fault is detected, the master device fault type is identified and corresponding operations are performed according to the identified fault type.

2. The battery pack parallel operation control method according to claim 1, characterized in that, The control method further includes: The master and slave devices enter a discharge mode and detect master and slave device faults. When a fault is detected in either the master or slave device, the fault type of the faulty master or slave device is identified, and corresponding operations are performed according to the identified fault type.

3. The battery pack parallel operation control method according to claim 2, characterized in that, The specific steps for detecting master-slave faults, identifying the fault type of either the master or slave when a fault is detected, and performing corresponding operations based on the identified fault type, include: When a host failure is detected, the host protection mechanism is activated to identify the host failure type and perform corresponding operations based on the identified failure type. When a fault is detected in the slave device, the faulty slave device activates its own protection mechanism and sends fault information to the master device. The master device receives the fault information sent by the faulty slave device, identifies the fault type of the slave device, and performs corresponding operations according to the identified fault type.

4. The battery pack parallel operation control method according to claim 3, characterized in that, The specific steps for performing the corresponding operation based on the identified fault category include: The host computer performs corresponding operations according to the identified fault category and a pre-set program. Based on the corresponding operations performed according to the pre-set program, the host sends a request message to the energy storage converter, so that the energy storage converter receives the request message sent by the host and adjusts the charging / discharging current accordingly.

5. The battery pack parallel operation control method according to claim 1, characterized in that, After determining the master and slave identities of the battery pack, the specific steps for the master in the battery pack to send information to each slave to confirm the online status of each slave include: Based on the determination of the master and slave identities of the battery pack, parallel operation information is sent to the slave, so that the online slave can receive and respond to the master's broadcast frame; The online status of the battery pack is determined by whether or not feedback information is received from the slave device in response to the master device's broadcast frame.

6. The battery pack parallel operation control method according to claim 5, characterized in that, The step of determining that a slave device is online specifically includes: Upon receiving feedback information from the slave device's broadcast frame in response to the master device, the slave device is confirmed to be online.

7. A battery management system, characterized in that, It includes a memory and a processor, the memory storing an application program, and the processor running the application program within the memory to perform the steps of the battery pack parallel control method as described in any one of claims 1-6.

8. A residential energy storage system, characterized in that, Includes multiple battery packs, energy storage converters, a host computer, and the battery management system as described in claim 7; The battery pack includes a master unit and multiple slave units. The master unit is communicatively connected to a host computer, and the master unit and slave units communicate with each other and with each other via RS-485 cables.

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