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

Abstract

The invention provides a battery pack parallel operation control method, a battery management system and a household energy storage system. The control method comprises the following steps: reading dial switch setting on a battery pack; the host in the battery pack sends information to each slave; when it is determined that the slave is online, the host requests the energy storage converter to pre-charge the host and the slave in the online state, enters a normal charging mode after pre-charging is completed, and detects the fault condition of the host and the slave; and when it is determined that no slave is online, the host requests the energy storage converter to charge the host, and the fault condition of the host is detected. The system has an emergency response mechanism, can quickly take actions according to the difference between the single-machine state and the parallel-machine state when abnormal conditions are detected, firstly executes a self protection mechanism, and then executes corresponding operation according to the identified fault category, so that the influence on the whole system is reduced to a greater extent.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a battery pack parallel control method, a battery management system and a household energy storage system. Background Art

[0002] With the development of renewable energy, more and more households are adopting energy storage systems to store excess electricity for use when needed. Household energy storage systems are usually composed of multiple battery packs, which can work independently or in parallel. In order for multiple battery packs to work together, there must be an effective control system 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 battery pack, and processing data exchange between them. Existing technologies lack an effective emergency response mechanism and cannot take quick action when abnormal conditions are detected, such as current limiting or disconnection, thereby minimizing the impact on the entire system. Summary of the invention

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

[0004] The present invention provides a battery pack parallel control method, which is applied to a household energy storage system. The energy storage system includes an energy storage converter and a plurality of parallel battery packs. Each of the battery packs is provided with a dip switch. The control method includes:

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

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

[0007] When it is determined that a slave is online, the host requests the energy storage converter to pre-charge the host and the slave in the online state, and enters the normal charging mode after completing the pre-charging, and detects the fault of the master and slave, so as to identify the fault type of the master and slave when any fault of the master and slave is detected, and perform corresponding operations according to the identified fault type;

[0008] When it is determined that no slave machine is online, the host requests the energy storage converter to charge the host and detect the host fault condition, so as to identify the host fault category when a host fault is detected, and perform corresponding operations according to the identified fault category.

[0009] Optionally, the control method further includes:

[0010] The master and slave machines enter a discharge mode and detect fault conditions of the master and slave machines, so that when a fault is detected in any of the master and slave machines, the fault type of the faulty master and slave machines is identified, and corresponding operations are performed according to the identified fault type.

[0011] Optionally, the specific steps of detecting the fault condition of the master and slave machines, identifying the fault type of the master and slave machines when a fault is detected in any of the master and slave machines, and performing corresponding operations according to the identified fault type include:

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

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

[0014] Optionally, the specific step of performing a corresponding operation according to the identified fault category includes:

[0015] The host performs corresponding operations according to the identified fault type and a preset program;

[0016] Based on executing corresponding operations according to a preset program, the host sends request information to the energy storage converter, so that the energy storage converter receives and adjusts the charging / discharging current according to the request information sent by the host.

[0017] Optionally, after determining the master and slave identities of the battery pack, the host in the battery pack sends information to each slave to confirm the online status of each slave, including:

[0018] Based on the master and slave identities of the battery pack, parallel information is sent to the slaves so that the online slaves receive and respond to the broadcast frames of the master;

[0019] The online status of the battery pack is determined based on whether the feedback information sent by the slave in response to the broadcast frame sent by the host is received.

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

[0021] When receiving the feedback information sent by the slave in response to the broadcast frame of the host, it is confirmed that the current slave is in an online state.

[0022] Optionally, each of the battery packs is provided with a terminal resistor, the host is communicatively connected to a host computer, and the host and the slave are communicatively connected in sequence according to the set number of the dip switch, and the control method further includes:

[0023] Based on the confirmation of the online status of the slave, the end slave among the currently online slaves is identified by reading the number of the DIP switch;

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

[0025] Optionally, a limited current loop is provided between the battery packs, and the control method further includes:

[0026] When it is determined that a slave is online, the current between the battery packs is detected. When it is detected that 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.

[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 execute the steps of the battery pack parallel control method as described above.

[0028] The present invention also provides a household energy storage system, comprising a plurality of battery packs, an energy storage converter, a host computer and the battery management system as described above;

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

[0030] The present invention proposes a battery pack parallel control method, which has an emergency response mechanism. When an abnormal situation is detected, it can take quick action according to the difference between the single machine and the parallel machine state, first execute its own protection mechanism, and then execute corresponding operations according to the identified fault category, thereby minimizing the impact on the entire system. At the same time, the control method sets the identity of the master and slave of the device through a dial switch, so that the slave only interacts with the master to prevent communication failures between the master and slave. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] Figure 1A flowchart of the steps of a battery pack parallel control method of the present invention;

[0033] Figure 2 A single / parallel SOP current reduction strategy table of a battery pack parallel control method of the present invention;

[0034] Figure 3 A flowchart of an embodiment of a battery pack parallel control method of the present invention;

[0035] Figure 4 A limiting loop circuit diagram of a battery pack parallel control method of the present invention;

[0036] Figure 5 A dial table diagram of a battery pack parallel control method of the present invention.

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

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] The present invention provides a battery pack parallel control method, which is applied to a household energy storage system. The energy storage system includes an energy storage converter and a plurality of parallel battery packs. Each of the battery packs is provided 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 and slave identities of the battery pack itself;

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

[0045] S300: When it is determined that a slave is online, the host requests the energy storage converter to pre-charge the host and the slave in the online state, and enters the normal charging mode after the pre-charging is completed, and detects the fault of the master and slave, so as to identify the fault type of the master and slave when any fault of the master and slave is detected, and perform corresponding operations according to the identified fault type;

[0046] S400: When it is determined that there is no slave machine online, the host requests the energy storage converter to charge the host and detect the host fault condition, so as to identify the host fault type when a host fault is detected, and perform corresponding operations according to the identified fault type.

[0047] More specifically, with the development of renewable energy, more and more households are beginning to adopt energy storage systems to store excess electricity for use when needed. Household energy storage systems are usually composed of multiple battery packs that can work independently or in parallel. In order for multiple battery packs to work together, there must be an effective control system 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 battery pack, and processing data exchange between them. The reliability and efficiency of the energy storage system are directly related to the user experience and the economic benefits of the system. Therefore, developing an efficient and stable parallel control strategy is crucial to improving the overall performance of the energy storage system.

[0048] Once a device failure occurs in the parallel battery pack control system currently on the market, it is necessary to promptly inform the energy storage converter (PCS, Power Conversion System) to perform corresponding power estimation (SOP, State of Power) current limiting operations to ensure system stability.

[0049] Therefore, the present application proposes a battery pack parallel control method, which aims to solve the problem that traditional household energy storage systems lack an effective emergency response mechanism and are unable to take prompt action when abnormal conditions are detected, such as current limiting or disconnecting, 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 and slave identities of the battery pack itself. Each battery pack should be equipped with a DIP switch, which is used to set the master and slave addresses. When the control system starts, it first reads the setting values ​​of these DIP switches to determine the role of each battery pack. Make sure that the DIP switch settings are correct, because incorrect settings may cause the system to malfunction or cause communication conflicts. Figure 5 In the dial table shown, 0 is the host address and the others are slaves. Each BMS can be a host, but there is only one host in each system. Make sure that the host and slave addresses are assigned correctly.

[0051] Specifically, each battery pack is also provided with an RS485-1 interface, an RS485-2 interface, an RS232 interface, a current limiting circuit and a terminal resistor. After determining the master and slave machines of the battery pack, the host needs to connect to the host computer through the RS232 interface. After connecting to the host computer, the maximum SOP and the number of parallel machines must be configured. The configuration of the maximum SOP involves the setting of the operating parameters of the battery system, while the configuration of the number of parallel machines determines the number of slaves that can be connected in the system. The host communicates with the slaves and the slaves communicate with each other through the RS485-2 interface. Through the RS485-2 interface, the host can poll and read the slave data, and is responsible for real-time monitoring of the status of all slaves, including but not limited to key parameters such as voltage, current, and temperature. In addition, the host communicates with the PCS through the RS485-1 interface.

[0052] In step S200, based on the master and slave identities of the battery pack, the host in the battery pack sends information to each slave to confirm the online status of each slave. Once the host determines its own identity, it will send an online status query request to all slaves through a communication link (such as RS485). After receiving the query request, the slave should immediately reply to the host to confirm its online status. Ensure the stability and reliability of the communication link to avoid misjudgment of the slave status due to communication failure.

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

[0054] At the same time as this step, the host starts its own terminal resistor, and after determining the online status of the slave, the host determines the end slave in the current online slave in combination with the dip switch, and controls the terminal resistor of the end slave to turn on. In the communication link, the terminal resistor is used to absorb the reflected wave on the signal line and improve the stability and accuracy of signal transmission. The host starts its own terminal resistor to ensure the integrity of the signal when communicating with the slave; the host determines the end slave in the current online slave by reading the setting of the dip switch or receiving the online status reply of the slave, combined with the topology of the communication link, and the host will send a command to it, requiring it to turn on the built-in terminal resistor.

[0055] In step S300, when it is determined that a slave is online, the host requests the energy storage converter (PCS) to pre-charge the host and the online slave, and enters the normal charging mode after completing the pre-charging, and detects the master and slave faults.

[0056] In order to protect the battery pack from current shock, the host will perform a pre-charge operation before requesting the PCS to charge the battery pack. Pre-charging usually connects the battery pack to the PCS through a small resistor to limit the initial charging current. After the pre-charging is completed, the host and slave will enter the normal charging mode, at which time the PCS will charge the battery pack with 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 the main power supply, thereby limiting the current and preventing instantaneous large currents from damaging the battery and circuit components.

[0057] When the system detects that a slave is online, it will first close the pre-charge relay. The pre-charge relay is connected between the pre-charge resistor and the battery to control the start and end of the pre-charge process. While closing the pre-charge relay, the system will disconnect the negative relay. The negative relay is usually connected between the negative pole of the battery and the rest of the circuit. Disconnecting the negative relay can prevent current from flowing directly through the battery and circuit components during the pre-charge process, thereby protecting them from the impact of instantaneous large currents.

[0058] With the pre-charge relay closed and the negative relay disconnected, the current will slowly charge the battery through the pre-charge resistor. This process will continue for a while until the battery voltage gradually rises to close to the operating voltage of the system. When the pre-charge process is completed, the system will disconnect the pre-charge relay. This marks the end of the pre-charge phase and is ready to enter the normal working phase. After disconnecting the pre-charge relay, the system will close the negative relay. In this way, the battery can be connected to the rest of the system through the normal circuit path and start normal operation.

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

[0060] In step S400, when it is determined that there is no slave online, the host requests the energy storage converter to charge the host and detect the host fault. If there is no slave online, the host will directly enter the charging mode without performing a pre-charging operation (because only the host battery pack needs to be charged at this time). In the single host charging mode, the host also needs to continuously monitor its own operating status and perform corresponding protection measures when a fault is detected.

[0061] It is worth noting that step S300 and step S400 are parallel steps, and either the slave is online or not. Regardless of whether the master or slave fails, the self-protection mechanism is first activated to ensure that when a device fails, measures can be taken quickly to prevent the spread of the fault, protect other parts of the system from damage, and minimize the impact on users. The content of the self-protection mechanism includes fault isolation, safe shutdown, alarm notification, etc.

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

[0063] When the voltage range is exceeded, current reduction will be performed in both single and parallel situations;

[0064] When an alarm-type current limiting fault occurs, the current is reduced or the system is shut down in a single-machine state, and in a parallel state;

[0065] When a protection-type current limiting fault occurs, in the single-machine state, the software and hardware will limit the current synchronously when the charging overcurrent protection current limiting occurs, and the machine will be shut down in other cases where a protection-type current limiting fault occurs; and in the parallel state, the software and hardware will limit the current synchronously when the charging overcurrent protection current limiting occurs, and the faulty slave machine will be shut down in other cases where a protection-type current limiting fault occurs, and the total current will be reduced by the number of faulty units * rated current.

[0066] In the parallel SOP current reduction strategy table, when multiple faults are triggered, to ensure the voltage consistency between the parallel machines, set the number of parallel machines and enable the parallel SOP through the host computer, and the requested charge and discharge current must not exceed the rated current of the battery.

[0067] The present invention proposes a battery pack parallel control method with an emergency response mechanism. When an abnormal situation is detected, the system will automatically select the most appropriate protection mechanism for intervention according to the difference between the single machine and the parallel machine state. For example, in the single machine state, the power supply may be directly cut off to avoid further damage, while in the parallel machine state, the output of other parallel battery packs may be adjusted to maintain system stability. Take action quickly, first execute its own protection mechanism, and then perform corresponding operations according to the identified fault category, so as to minimize the impact on the entire system. At the same time, the control method sets the identity of the master and slave of the device through a dial switch, so that the slave only interacts with the host to prevent communication failures between the master and slave.

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

[0069] The master and slave machines enter a discharge mode and detect fault conditions of the master and slave machines, so that when a fault is detected in any of the master and slave machines, the fault type of the faulty master and slave machines is identified, and corresponding operations are performed according to the identified fault type.

[0070] When the energy storage system needs to power an external load, the master and slave will enter the discharge mode according to the system's instructions or preset conditions. In the discharge mode, the battery pack releases the stored electrical energy and converts it into electrical energy suitable for the load through the energy storage converter (PCS). During the discharge process, the master and slave will continuously monitor their respective operating status, including key parameters such as voltage, current, and temperature. Changes in these parameters can reflect the health and performance status of the battery pack. Once an abnormal parameter or trend is detected, the system will immediately trigger the fault detection mechanism. Based on the identified fault category, the system will execute corresponding protection measures to prevent the fault from further deteriorating or spreading. For over-discharge faults, the system may immediately cut off the discharge circuit to prevent the battery pack from being damaged due to excessive discharge.

[0071] In one embodiment, the specific steps of detecting the fault condition of the master and slave machines, identifying the fault type of the master and slave machines when a fault is detected in any of the master and slave machines, and performing corresponding operations according to the identified fault type include:

[0072] When a fault is detected in the host, the host protection mechanism is started, the host fault category is identified, and corresponding operations are performed according to the identified fault category; when a fault is detected in the slave, the faulty slave starts its own protection mechanism and sends fault information to the host, the host receives the fault information sent by the faulty slave, identifies the slave fault category, and performs corresponding operations according to the identified fault category.

[0073] Among them, the identified fault types include exceeding the voltage range, warning current limiting and protection current limiting. According to the identified fault type, the host executes the preset response measures. Figure 2 For faults that exceed 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 use of some services to avoid fault escalation. For protection-type current limiting, the host will immediately cut off the power supply of the faulty part to protect other parts of the system from damage.

[0074] In one embodiment, the specific steps of performing corresponding operations according to the identified fault type include:

[0075] The host performs corresponding operations according to the identified fault type and a preset program; based on performing the corresponding operations according to the preset program, the host sends request information to the energy storage inverter so that the energy storage inverter receives and adjusts the charging / discharging current according to the request information sent by the host.

[0076] The host can detect the occurrence of faults in real time and accurately identify the specific type of fault through the built-in monitoring and diagnostic system. Once the fault type is determined, the host will perform the corresponding operation according to the previously preset program or strategy. These preset programs may cover a variety of fault scenarios and corresponding countermeasures. As part of the countermeasures, the host will generate corresponding request information based on the impact of the current fault and the actual needs of the system, and send it to the energy storage inverter through the communication interface.

[0077] The energy storage inverter has a communication function and can receive request information from the host in real time. After receiving the request information, the energy storage inverter will parse it to understand the specific operation that the host wants it to perform, that is, to adjust the size of the charging or discharging current. According to the parsed request information, the energy storage inverter will adjust its internal power conversion logic to change the size of the charging or discharging current. This adjustment is intended to ensure the stable operation of the system or reduce the impact of faults on the system.

[0078] According to the above 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 SOP after current reduction to the PCS, and the PCS performs 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, after determining the master and slave identities of the battery pack, the host in the battery pack sends information to each slave to confirm the online status of each slave, including:

[0080] Based on the master and slave identities of the battery pack, the parallel information is sent to the slaves so that the online slaves receive and respond to the broadcast frames of the master. Before this step, the system has determined which device in the battery pack is the master and which devices are slaves by reading the settings of the dip switches. Once the master and slave identities are determined, the master will send a broadcast frame containing the parallel information to all slaves to inform the slaves that the master is ready and ready for subsequent communication and status confirmation. The broadcast frame is a special communication frame used to send information to all slaves without knowing the specific address of each slave.

[0081] The online status of the battery pack is determined based on whether the feedback information sent by the slave in response to the broadcast frame sent by the host is received. The online slave will receive the broadcast frame sent by the host. The slave that receives the broadcast frame will send feedback information to the host according to the preset protocol or rules. This feedback information usually includes the identity information and status information of the slave, which is used to inform the host that the slave is online and can communicate normally. After sending the broadcast frame, the host will wait for a period of time to receive feedback information from the slave. During this period of time, the host will continue to monitor the communication channel to detect whether any slave has sent feedback information. Based on the received feedback information, the host can determine which slaves are online. If no feedback information is received from a slave, the host may think that the slave is offline or has a fault. The host will record the online status of each slave and perform further processing as needed. If a slave is detected to be offline or faulty, the host may start the corresponding protection mechanism, such as alarm, log recording, and attempt to re-establish communication.

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

[0083] When receiving the feedback information sent by the slave in response to the host's broadcast frame, it is confirmed that the current slave is online. The online slave will receive the host's broadcast frame and send feedback information to the host according to the preset communication protocol or rules. This feedback information usually contains the identity information of the slave, which is used to confirm the identity and online status of the slave. When the host receives the feedback information from the slave, it will immediately confirm that the slave is online. This is because the receipt of the feedback information directly proves that the slave can receive the host's broadcast frame and can communicate normally. Once the slave is confirmed to be online, the host will record this status and may perform further processing as needed. For example, the host may update the system status information, send notifications to users, or adjust the system's operating mode according to the number of online slaves.

[0084] In one embodiment, if Figure 3 As shown, each battery pack is provided with a terminal resistor, the host is connected to the host computer for communication, and the host and the slave are connected to each other in sequence according to the set number of the dip switch, and the control method further includes:

[0085] S510: Based on the confirmation of the online status of the slave, the end slave among the currently online slaves is identified by reading the number of the DIP switch;

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

[0087] In step S510, based on the confirmation of the online status of the slave, the dip switch number is read. Each slave is provided with a dip switch for setting its unique number or address. The host reads the dip switch number of each online slave in turn through the communication connection. The slave dip switches are numbered 1 to 15. According to the set number of the dip switch, the host can identify the last one of the current online slaves, that is, the end slave. This is achieved by comparing the numbers of all online slaves. The slave with the largest number is considered to be the end slave. For example, if the online slaves are numbered 1, 7, and 12, then number 12 is the end slave.

[0088] In step S520, after identifying the end slave, the host first turns on its own terminal resistor. Terminal resistors are usually used at the end of a communication line to provide appropriate impedance matching and reduce signal reflection and interference. Then, the host sends a control instruction to the end slave, requiring it to turn on its own terminal resistor. After receiving the instruction, the end slave will perform the corresponding operation and turn on its terminal resistor.

[0089] 485 communication belongs to bus communication, and its physical layer interface signal is 485A / 485B. Devices that need to communicate hang their respective 485 communication networks on bus 485A / 485B. When multiple devices communicate with each other, in order to stabilize the communication, a terminal resistor needs to be connected in parallel between the 485A / 485B of the first device and the last device. Most systems rely on fixed terminal resistance configuration. Although this method is simple, it requires manual installation of matching resistors, which greatly increases the risk of errors during on-site installation. This application adopts a dynamic terminal resistance control mechanism to automatically adjust the terminal resistance according to the actual situation of the communication network, reduce human intervention, and improve the reliability and maintenance convenience of the system.

[0090] In one embodiment, if Figure 4 As shown, a limited current circuit is provided between the battery packs, and the control method further includes:

[0091] When it is determined that a slave is online, the current between the battery packs is detected. When it is detected that 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. Figure 4 As shown in the figure, multiple battery packs are connected to the load, and a switch is set between the battery pack and the load. By controlling the switch in the current limiting loop, the circulating current is reduced and brought back into the safe range. The current limiting loop will not stop working after one adjustment, but will continue to monitor current changes and dynamically adjust the current limiting strength based on real-time data. This closed-loop control mechanism ensures that the system can maintain stable operation under various working conditions.

[0092] Through the current limiting circuit, the battery pack parallel system can achieve stable operation even under large voltage differences, reducing the dependence on the battery pack voltage consistency. By dynamically controlling the circulating current, the system can reduce voltage instability caused by current fluctuations and improve the reliability of overall operation. By reducing the impact of the circulating current on the battery pack, the system can effectively reduce the risk of battery overheating or overcharging / overdischarging, and extend the battery life. The current limiting circuit can effectively prevent short circuits or thermal runaway caused by excessive circulating current, improving the safety of the system.

[0093] 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 execute the steps of the battery pack parallel control method as described above. The battery pack parallel control method has an emergency response mechanism, which can take quick action when an abnormal situation is detected according to the difference between the single machine and the parallel state, first execute its own protection mechanism, and then execute corresponding operations according to the identified fault category, thereby minimizing the impact on the entire system.

[0094] The present invention also proposes a household energy storage system, including multiple battery packs, energy storage converters, a host computer and a battery management system as described above; the battery pack includes a host and multiple slaves, the host is communicatively connected to the host computer, and the host and the slaves and the slaves communicate with each other via RS-485 cables. The present application sets the identities of the master and slave devices of the equipment through a dip switch, and stipulates that the host and the PCS and the host computer perform data exchange, and the slave only interacts with the host. In addition, when the system is paralleled, the current limiting circuit is used for protection to prevent excessive circulating current. At the same time, the system also designs a terminal resistance control mechanism for the RS-485 communication line to ensure the stability and reliability of communication. Finally, when any abnormal situation is detected, the system will execute its own protection logic and upload the parallel SOP to the PCS through the host for current limiting to ensure the safe operation of the system.

[0095] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A battery pack parallel control method, applied to a household energy storage system, wherein the energy storage system comprises an energy storage converter and a plurality of parallel battery packs, characterized in that: Each of the battery packs is provided with a dip switch, and the control method comprises: Read the DIP switch settings on the battery pack to determine the master and slave identities of the battery pack itself; After determining the master and slave identities of the battery pack, the host in the battery pack sends information to each slave to confirm the online status of each slave; When it is determined that a slave is online, the host requests the energy storage converter to pre-charge the host and the slave in the online state, and enters the normal charging mode after completing the pre-charging, and detects the fault of the master and slave, so as to identify the fault type of the master and slave when any fault of the master and slave is detected, and perform corresponding operations according to the identified fault type; When it is determined that no slave machine is online, the host requests the energy storage converter to charge the host and detect the host fault condition, so as to identify the host fault category when a host fault is detected, and perform corresponding operations according to the identified fault category.

2. The battery pack parallel control method according to claim 1, characterized in that: The control method further comprises: The master and slave machines enter a discharge mode and detect fault conditions of the master and slave machines, so that when a fault is detected in any of the master and slave machines, the fault type of the faulty master and slave machines is identified, and corresponding operations are performed according to the identified fault type.

3. The battery pack parallel control method according to claim 2, characterized in that: The specific steps of detecting the fault of the master and slave machines, identifying the fault type of the master and slave machines when a fault is detected in any of the master and slave machines, and performing corresponding operations according to the identified fault type include: When a host failure is detected, a host protection mechanism is activated to identify the host failure type and perform corresponding operations according to the identified failure type; When a fault is detected in a slave, the faulty slave starts its own protection mechanism and sends fault information to the host. The host receives the fault information sent by the faulty slave, identifies the slave fault category, and performs corresponding operations according to the identified fault category.

4. The battery pack parallel control method according to claim 3, characterized in that: The specific steps of performing corresponding operations according to the identified fault category include: The host performs corresponding operations according to the identified fault type and a preset program; Based on executing corresponding operations according to a preset program, the host sends request information to the energy storage converter, so that the energy storage converter receives and adjusts the charging / discharging current according to the request information sent by the host.

5. The battery pack parallel control method according to claim 1, characterized in that: After determining the master and slave identities of the battery pack, the host in the battery pack sends information to each slave to confirm the online status of each slave. The specific steps include: Based on the master and slave identities of the battery pack, parallel information is sent to the slaves so that the online slaves receive and respond to the broadcast frames of the master; The online status of the battery pack is determined based on whether the feedback information sent by the slave in response to the broadcast frame sent by the host is received.

6. The battery pack parallel control method according to claim 5, characterized in that: The step of determining whether a slave machine is online specifically includes: When receiving the feedback information sent by the slave in response to the broadcast frame of the host, it is confirmed that the current slave is in an online state.

7. The battery pack parallel control method according to any one of claims 1 to 6, wherein each of the battery packs is provided with a terminal resistor, characterized in that: The host is connected to the host computer by communication, and the host is connected to the slave by communication in sequence according to the set number of the dial switch. The control method also includes: Based on the confirmation of the online status of the slave, the end slave among the currently online slaves is identified by reading the number of the DIP switch; The terminal resistance of the host itself is turned on, and the terminal resistance of the control end slave is turned on.

8. The battery pack parallel control method according to any one of claims 1 to 6, characterized in that: A current limiting circuit is provided between the battery packs, and the control method further comprises: When it is determined that a slave is online, the current between the battery packs is detected. When it is detected that 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.

9. A battery management system, characterized in that: It includes a memory and a processor, the memory stores an application program, and the processor is used to run the application program in the memory to execute the steps of the battery pack parallel control method as described in any one of claims 1 to 8.

10. A household energy storage system, characterized in that: It includes a plurality of battery packs, an energy storage converter, a host computer and a battery management system as claimed in claim 9; The battery pack includes a host and multiple slaves. The host is communicatively connected to a host computer. The host and the slaves and the slaves communicate with each other via RS-485 cables.

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