Control method of high-voltage household energy storage system

Abstract

The application discloses a control method of a high-voltage household energy storage system, comprising the following steps: when it is determined that at least one battery cluster has an over-discharge protection fault, generating a forced charging signal and sending the signal to an energy storage inverter when each switch assembly is closed, so that the energy storage inverter controls the high-voltage household energy storage system to enter a forced charging mode and charges each battery cluster in the forced charging mode; obtaining the current of the positive or negative terminal, and controlling each switch assembly to be disconnected when it is determined that the system charging fails; returning to the step of determining that at least one battery cluster has an over-discharge protection fault after a set interval, until it is determined that the charging is successful. By forcibly controlling the switch assembly to be closed and the energy storage inverter to enter the forced charging mode, the charging of the battery cell when the voltage is too low can be realized, and the problem that the charging prohibition cannot be conveniently and automatically solved in the absence of an upper computer operating environment is solved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage residential energy storage system technology, and more particularly to a control method for high-voltage residential energy storage systems. Background Technology

[0002] High-voltage residential energy storage systems typically consist of a battery management system, battery modules, inverters, photovoltaics, and mains power. The inverter can send message commands to the battery management system via CAN communication, and the battery management system controls the closing of the battery main circuit relay, thereby enabling the photovoltaics or the grid to charge the battery and the battery to discharge to the residential load.

[0003] Even when the battery packs are stationary for extended periods or do not receive charging from the system, the battery management system and inverter will still consume power from them. When the minimum cell voltage falls below a set threshold, the system will disconnect the main circuit contactor to prevent further battery discharge. Simultaneously, the system will trigger a level three low-voltage alarm. At this point, the system cannot charge the battery. Furthermore, as the system continues to self-discharge the battery, the cell voltage continues to drop. To prevent further self-discharge, the system will disconnect the circuit breaker, shutting down the entire system. Even if the circuit breaker is manually closed subsequently, the low-voltage fault persists, and the battery packs cannot charge the system.

[0004] In related technologies, when the battery module voltage is too low, the alarm threshold for low cell voltage is modified via a host computer to restore the alarm and allow charging to proceed. The alarm threshold is then updated again via the host computer. However, this method lacks a host computer operating environment for residential users operating high-voltage residential energy storage systems. It cannot conveniently and automatically resolve charging restrictions caused by low cell voltage, resulting in high operational barriers and difficulties in after-sales maintenance. Summary of the Invention

[0005] This invention provides a control method for a high-voltage residential energy storage system to solve the problem of not being able to conveniently and automatically resolve charging prohibition when there is a lack of a host computer operating environment.

[0006] According to one aspect of the present invention, a control method for a high-voltage residential energy storage system is provided. The high-voltage residential energy storage system includes: an energy storage inverter, at least one battery cluster, at least one battery management system corresponding to the at least one battery cluster, and at least one switching component corresponding to the at least one battery cluster. The battery cluster includes multiple battery components, and the battery cluster and the corresponding switching component are connected in series between the positive terminal and the negative terminal of the high-voltage residential energy storage system. The battery management system is respectively connected to each battery component in the corresponding battery cluster and the switching component corresponding to the battery cluster. The energy storage inverter is also respectively connected to the positive terminal and the negative terminal. Any one of the at least one battery management system is used as a host, and the control method of the high-voltage residential energy storage system is executed by the host. The control method of the high-voltage residential energy storage system includes: When it is determined that at least one battery cluster has an over-discharge protection fault, a strong charging signal is generated and sent to the energy storage inverter when all the switching components are closed, so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each battery cluster in the strong charging mode; when the voltage of at least one battery cell of at least one battery component in the battery cluster is less than a first set threshold or the charge is less than a first charge threshold, the battery cluster has the over-discharge protection fault. The system acquires the current at the positive or negative terminal and controls each of the switching components to disconnect when the high-voltage residential energy storage system fails to charge, based on the current. After a set interval, the process returns to the step of obtaining the switching status of each switch component when it is determined that at least one battery cluster has an over-discharge protection fault, and controlling the unclosed switch components to close, until all the switch components are closed, until the high-voltage residential energy storage system is successfully charged.

[0007] Optionally, when it is determined that the high-voltage residential energy storage system has failed to charge based on the current, after controlling each of the switching components to disconnect, the method further includes: incrementing the charging failure flag by 1; After the high-voltage residential energy storage system is successfully charged, the following steps are also included: clearing the charging failure flag bit to zero. The set duration is positively correlated with the current value of the charging failure flag.

[0008] Optionally, when the value of the charging failure flag reaches a preset value, the set duration is fixed to a preset value; the preset value is the set duration corresponding to when the value of the charging failure flag is equal to the preset value.

[0009] Optionally, after acquiring the current at the positive or negative terminal and determining that the high-voltage residential energy storage system has been successfully charged based on the current, the method further includes: If the voltage of each individual battery cell in each battery cluster is greater than the second set threshold, or if the voltage of each individual battery cell in each battery cluster increases by a preset amount, a strong charging stop signal is sent to the energy storage inverter to cause the high-voltage residential energy storage system to exit the strong charging mode.

[0010] Optionally, the high-voltage residential energy storage system includes at least two battery clusters and at least two battery management systems, with each battery management system except the host acting as a slave. Before generating a strong charging signal and sending it to the energy storage inverter when all the switching components are closed, and after determining that at least one battery cluster has an over-discharge protection fault, so that the energy storage inverter controls the high-voltage residential energy storage system to enter a strong charging mode, and before charging each of the battery clusters in the strong charging mode, the method further includes: The parallel operation sequence of each battery cluster is determined according to the order of their voltages from smallest to largest; battery clusters with the same voltage are paralleled simultaneously. The switch assembly corresponding to the first battery cluster that needs to be paralleled is closed to complete the paralleling process; For each battery cluster that needs to be paralleled except for the first one: when the difference between the voltage of the current battery cluster that needs to be paralleled and the average voltage of all battery clusters that have been paralleled is greater than the paralleling difference threshold, a strong charging paralleling signal is generated and sent to the energy storage inverter, so that the energy storage inverter controls the high-voltage residential system to enter the strong charging mode, and charges the paralleled battery clusters in the strong charging mode. When all the battery clusters that have been connected to the grid are charged to the voltage of the next battery cluster that needs to be connected to the grid, a strong charging stop signal is sent to the energy storage inverter so that the high-voltage residential energy storage system exits the strong charging mode, the energy storage inverter stops charging the battery clusters, and controls the switch components corresponding to the battery cluster that needs to be connected to the grid to close. When the difference between the voltage of the battery cluster that needs to be paralleled and the average voltage of all battery clusters that have been paralleled is less than or equal to the paralleling difference threshold, the switch component corresponding to the battery cluster that needs to be paralleled is controlled to close to complete the paralleling.

[0011] Optionally, the control method for the high-voltage residential energy storage system further includes: For any of the battery clusters, if it is determined that the battery cluster does not have the over-discharge protection fault or any preset fault, the battery management system corresponding to the battery cluster is controlled to enter the shutdown mode; the preset fault is a fault that affects the closing of the switching component, other than the over-discharge protection fault. Upon receiving the charge / discharge signal output by the energy storage inverter, the switch component corresponding to each battery management system in the standby mode is controlled to close to enter the normal operation mode.

[0012] Optionally, the control method for the high-voltage residential energy storage system further includes: If the battery cluster has not been charged or discharged for a first set time based on the current of any closed switch component, and at the same time the voltage of at least one battery cell in the battery cluster is less than the first set threshold and the average voltage of all the battery cells is less than the second set threshold, the battery management system corresponding to the battery cluster is controlled to enter a first sleep mode; the second set threshold is greater than the first set threshold.

[0013] Optionally, in the first sleep mode, within one working cycle, the battery management system, which is controlled to enter the first sleep mode, sequentially collects the voltage of each battery cell in each battery component of the battery cluster corresponding to the battery management system m times at a preset sampling interval.

[0014] Optionally, the control method for the high-voltage residential energy storage system further includes: When the switching component corresponding to any battery cluster remains disconnected for a second set duration, and the voltage of at least one battery cell in the battery cluster is less than the first set threshold, the battery management system corresponding to the battery cluster is controlled to enter a second sleep mode.

[0015] Optionally, in the second sleep mode, within one working cycle, the battery management system, which is controlled to enter the second sleep mode, sequentially collects the voltage of each battery cell in each battery component of the battery cluster corresponding to the battery management system m times at a preset sampling interval.

[0016] Control methods for high-voltage residential energy storage systems also include: When it is determined that the voltage of a single battery cell in at least one battery cluster is greater than the first set threshold and less than the second set threshold, or the charge of at least one battery cell is greater than the first charge threshold and less than the second charge threshold, a strong charging signal is generated and sent to the energy storage inverter after all the switching components are closed, so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each battery cluster in the strong charging mode; the second set threshold is greater than the first set threshold, and the second charge threshold is greater than the first charge threshold.

[0017] In this embodiment, a low-voltage alarm signal is generated when the voltage of a single battery cell is too low. After all switching components are closed, a strong charging signal is generated and transmitted to the energy storage inverter. This causes the energy storage inverter to control the high-voltage residential energy storage system to enter strong charging mode, allowing the battery cluster to charge in this mode. By forcibly controlling the high-voltage residential energy storage system to enter strong charging mode, charging is performed when the voltage of a single battery cell is too low, thus solving the problem of stopping charging when the battery voltage is too low. Forced charging is triggered when the voltage of a single battery cell is too low to prevent the battery cluster from being completely discharged and damaged. After strong charging, the current in the charging circuit is used to determine whether charging was successful. If charging fails, strong charging is retried to improve charging reliability. In the event of charging failure, strong charging is retried at set intervals to avoid increased power consumption caused by frequent strong charging operations.

[0018] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart of a control method for a high-voltage residential energy storage system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a high-voltage residential energy storage system provided in an embodiment of the present invention; Figure 3 A flowchart of another control method for a high-voltage residential energy storage system provided in an embodiment of the present invention; Figure 4 A flowchart of another control method for a high-voltage residential energy storage system provided in an embodiment of the present invention; Figure 5 This is a working block diagram of a high-voltage residential energy storage system during parallel operation, provided in an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] Figure 1 This invention provides a flowchart of a control method for a high-voltage residential energy storage system, applicable to such a system. Figure 2 This is a schematic diagram of a high-voltage residential energy storage system provided in an embodiment of the present invention, with reference to... Figure 2 The high-voltage residential energy storage system includes: an energy storage inverter 1, at least one battery cluster, at least one battery management system corresponding to the at least one battery cluster, and at least one switching component corresponding to the at least one battery cluster; the battery cluster includes multiple battery components 2, and the battery cluster and the corresponding switching component 2 are connected in series between the positive terminal BUS+ and the negative terminal BUS- of the high-voltage residential energy storage system; the battery management system is connected to each battery component 2 in the battery cluster corresponding to the battery management system and the corresponding switching component of the battery cluster; the energy storage inverter 1 is also connected to the positive terminal BUS+ and the negative terminal BUS+; any one of the at least one battery management systems is used as the host.

[0024] The battery management system corresponds one-to-one with each battery cluster, and the switching components also correspond one-to-one with each battery cluster. For any given battery cluster, multiple battery components 2 within that cluster are connected in series and / or in parallel. Figure 2The example illustrates a battery cluster comprising n battery modules, with battery modules Pack1 to Packn connected in series. For any given switching assembly, there are a first switch K1, a second switch K2, a fourth switch K4, and a fifth switch K5. The second switch K2 includes a first sub-section and a second sub-section. The first sub-sections of the first and second switches K1 and K2 are connected in series between the negative terminal of the corresponding battery cluster and the negative terminal BUS- of the high-voltage residential energy storage system. A pre-charge resistor R1 is connected in series with the fourth switch K4 and then in parallel with the fifth switch K5. The pre-charge resistor R1, the first sub-sections of the fourth switch K4 and the second switch K2 are connected in series between the positive terminal BUS+ of the high-voltage residential energy storage system and the positive terminal of the battery cluster. The first and second sub-sections of the second switch K2 have the same switching state. The battery management system includes a battery control unit 31 (BCU) and at least one battery management unit 32 (BMU), with each battery module 2 corresponding to one of the battery modules. When a battery cluster comprises n battery modules, the corresponding battery management system includes n battery management units 32, from BMU1 to BMUN. The communication method between the energy storage inverter 1 and the battery control unit 31 is CAN communication, and the communication method between the battery control unit 31 and the battery management units 32 is daisy-chain. If the high-voltage residential energy storage system includes multiple battery clusters, the communication method between the battery management units 32 in different battery management systems is daisy-chain communication. The host communicates with the energy storage inverter 1. Each battery module 2 includes multiple battery cells, which are connected in series and / or parallel.

[0025] The control method for the high-voltage residential energy storage system is executed by the main unit, specifically by the battery control unit 31 of the main unit. (See reference...) Figure 1 and Figure 2 Optionally, the method includes: S110: When it is determined that at least one battery cluster has an over-discharge protection fault, after all switching components are closed, a strong charging signal is generated and sent to the energy storage inverter, so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode, and charges each battery cluster in the strong charging mode. Specifically, the battery cluster has an over-discharge protection fault if the voltage of at least one cell in at least one battery component in the battery cluster is less than a first set threshold or the charge level is less than a first charge level threshold.

[0026] A high-voltage residential energy storage system may include one battery cluster or at least two battery clusters. When the high-voltage residential energy storage system includes one battery cluster, it also includes one battery management system, which acts as the master. When the battery management system includes at least two battery clusters, it also includes at least two battery management systems. The battery management system that communicates with the energy storage inverter 1 acts as the master, and the remaining battery management systems that do not communicate with the energy storage inverter 1 act as slaves.

[0027] Optionally, prior to S110, the method further includes acquiring the voltage of each individual cell in each battery cluster in real time, and determining whether at least one battery cluster has an over-discharge protection fault based on the voltage of each individual cell in each battery cluster. Specifically, for each battery cluster, the method determines whether the battery cluster has an over-discharge protection fault based on the voltage of each individual cell in that battery cluster.

[0028] For any given battery cluster, the battery control unit 31 of the battery management system corresponding to the battery cluster obtains the parameter information of each battery component in the battery cluster through the battery management units 32 of the battery management system corresponding to the battery cluster. The parameter information includes at least the voltage, temperature and other information of each individual battery cell in the battery component.

[0029] For any battery cluster, when the voltage of at least one battery cell in the battery cluster is less than a first set threshold or the charge of at least one battery cell is less than a first charge threshold, the battery management system (specifically the battery control unit 31) corresponding to the battery cluster determines that the battery cluster has an over-discharge protection fault and transmits the information about the over-discharge protection fault to the host, so that the host can determine whether each battery cluster has an over-discharge protection fault.

[0030] The host obtains the switch status of the corresponding switch component, and the slave obtains the switch status of the corresponding switch component and sends the switch status to the host. Thus, the host can obtain the switch status of each switch component directly and indirectly. The switch status includes closed and open states. When all switches in a switch component are closed, the switch component is in the closed state; when at least one switch in a switch component is open, the switch component is in the open state.

[0031] When the host determines that the switch component corresponding to each battery cluster is not closed, it controls the closed switch component to close until all switch components corresponding to all battery clusters are closed, and then generates a strong charging signal. Alternatively, when the host determines that the switch component corresponding to each battery cluster is closed, it directly generates a strong charging signal. In this case, the host indirectly controls the operation of the switch component corresponding to the battery cluster of the slave device. In this embodiment, when the host determines that a battery cluster has an over-discharge protection fault, it silences the fault to force the switch components to close and generate a strong charging signal, so that the battery cluster charges in strong charging mode.

[0032] In this case, for any switch assembly, the second switch is usually in a closed state under the user's control. When the battery control unit 31 controls the switch assembly to close, it first controls the first switch K1 and the fourth switch K4 to close. Then, after a preset pre-charging time, it controls the fifth switch K5 to close and the fourth switch K4 to open.

[0033] When the host determines that at least one battery cluster has an over-discharge protection fault, it generates a strong charging signal and sends it to the energy storage inverter 1. Upon receiving the strong charging signal, the energy storage inverter 1 controls the high-voltage residential energy storage system to enter strong charging mode. In strong charging mode, the energy storage inverter 1 only allows the battery clusters to charge and does not allow them to discharge; that is, in strong charging mode, only photovoltaic units 4 are allowed to charge the battery clusters, and the grid 5 or load 6 is not allowed to draw power from the battery clusters. The energy storage inverter 1 is connected to the grid 5 and the load 6 via meters 7.

[0034] The first set threshold is the maximum voltage of a single battery cell that triggers the high-voltage residential energy storage system to enter the intensive charging mode, and the first capacity threshold is the maximum capacity of a single battery cell that triggers the high-voltage residential energy storage system to enter the intensive charging mode. The first set threshold can be 2.88V, and the first capacity threshold can be 10% of the full capacity. Both parameters are set according to the actual project requirements.

[0035] Specifically, after determining that at least one battery cluster has an over-discharge protection fault, the over-discharge protection fault is silenced to prevent the battery control unit 31 from responding to the over-discharge protection fault and controlling the switching components in the main circuit to disconnect (meaning disconnecting at least one of the first switch K1 and the fifth switch K5) so that the battery cluster can be charged.

[0036] S120: Obtain the current at the positive or negative terminal and determine whether the high-voltage residential energy storage system has failed to charge based on the current. If not, execute S140; if yes, execute S150.

[0037] S130: Maintain the current state.

[0038] S140: Controls each switch component to disconnect, with a set interval duration.

[0039] After S110, after a preset detection interval (e.g., 2 minutes), proceed to step S120. The current at the positive terminal BUS+ or the negative terminal BUS- is acquired; in practice, this means acquiring the current on the main circuit of each battery cluster's circuit. If several currents are less than zero and greater than the charging current threshold, or if the current of a battery cluster is greater than the discharging current threshold, the high-voltage residential energy storage system is determined to have failed to charge. The charging current threshold is less than 0, and its absolute value represents the minimum absolute current value at which the high-voltage residential energy storage system successfully charges. The discharging current threshold is greater than 0, and its minimum current value at which the high-voltage residential energy storage system successfully discharges. A current greater than zero indicates that the battery cluster is discharging, and a current less than zero indicates that the battery cluster is charging.

[0040] When the host controls each switching component to disconnect, specifically, it controls at least one of the first switch K1 and the fifth switch K5 of each switching component to disconnect. After controlling each switching component to disconnect, after a set time interval, it returns to execute S110.

[0041] In one optional implementation, the set time interval between each determination of charging failure of the high-voltage residential energy storage system and the return to re-execution of S110 can be the same, i.e., the set time interval is a fixed value, such as 20 minutes. When the charging failure of the high-voltage residential energy storage system is determined, the host controls all switching components to open. After the set time interval, it returns to the steps of closing the control of the unclosed switching components and sending a strong charging signal to the energy storage converter to attempt to charge the battery pack again in strong charging mode. If charging fails again, after the set time interval, the steps of closing the control of the unclosed switching components and sending a strong charging signal to the energy storage converter are repeated until charging is successful. At this point, the host can remain inactive, maintaining the current state, allowing the battery pack to charge in strong charging mode.

[0042] In this embodiment, a low-voltage alarm signal is generated when the voltage of a single battery cell is too low. After all switching components are closed, a strong charging signal is generated and transmitted to the energy storage inverter. This causes the energy storage inverter to control the high-voltage residential energy storage system to enter strong charging mode, allowing the battery cluster to charge in this mode. By forcibly controlling the high-voltage residential energy storage system to enter strong charging mode, charging is performed when the voltage of a single battery cell is too low, thus solving the problem of stopping charging when the battery voltage is too low. Forced charging is triggered when the voltage of a single battery cell is too low to prevent the battery cluster from being completely discharged and damaged. After strong charging, the current in the charging circuit is used to determine whether charging was successful. If charging fails, strong charging is retried to improve charging reliability. In the event of charging failure, strong charging is retried at set intervals to avoid increased power consumption caused by frequent strong charging operations.

[0043] Optionally, the control method for the high-voltage residential energy storage system further includes, when it is determined that the voltage of a single cell in at least one battery cluster is greater than a first set threshold and less than a second set threshold, or that the charge of at least one single cell is greater than a first charge threshold and less than a second charge threshold, generating a strong charging signal and sending it to the energy storage inverter after all switching components are closed, so that the energy storage inverter controls the high-voltage residential energy storage system to enter a strong charging mode and charges each battery cluster in the strong charging mode. When the voltage of a single cell in a battery cluster is detected to drop to the second set threshold, if all switching components are closed, a strong charging signal is generated and sent to the energy storage inverter; if any switching component is open, the switching component is first controlled to close before generating a strong charging signal and sending it to the energy storage inverter to charge each battery cluster. The second set threshold is greater than the first set threshold, and the second power threshold is greater than the first power threshold. For example, if the first set threshold is 2.88V, the second set threshold can be 3.15V. The first power threshold can be 10% of the full power and the second power threshold can be 15% of the full power, so that the strong charging mode can be activated in advance to charge the battery cluster before the voltage of the battery cluster drops to the first set threshold or the first power threshold.

[0044] Figure 3 A flowchart of another control method for a high-voltage residential energy storage system provided in an embodiment of the present invention is shown below. Figure 3 The method includes: S111: When it is determined that at least one battery cluster has an over-discharge protection fault, after all the switching components are closed, a strong charging signal is generated and sent to the energy storage inverter so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each of the battery clusters in the strong charging mode.

[0045] S121: Obtain the current at the positive or negative terminal and determine whether the high-voltage residential energy storage system has failed to charge based on the current. If not, execute S131; if yes, execute S141.

[0046] S131: Clear the charging failure flag.

[0047] S141: Control each switching component to disconnect and increment the charging failure flag by 1.

[0048] S151: Determine whether the value of the failure flag has reached the preset value. If yes, execute S161, which is to return to step S111 after an interval of the preset value. If no, execute S171, which is to return to step S111 after an interval of the set time. The set time is positively correlated with the current value of the charging failure flag.

[0049] When a high-voltage residential energy storage system fails to charge based on the current in the main circuit of the loop containing the positive and negative terminals, all switching components are opened, and the charging failure flag is incremented by 1. After a set interval, the process returns to step S111 until charging is successful, at which point the charging failure flag is cleared. The set interval is positively correlated with the current value of the charging failure flag of the high-voltage residential energy storage system. "Current" can be understood as the current moment. The larger the cumulative number of charging failures at the current moment, the larger the corresponding set interval. In one optional implementation, the set interval is equal to M minutes * N, where N is the cumulative number of current charging failures, i.e., the value of the charging failure flag. Specifically, after the first charging failure, after an interval of M minutes (e.g., 20 minutes), the process returns to step S111. When charging failure is determined again based on the acquired current, the charging failure flag is incremented by 1, and all switching components are opened. After an interval of 2 * M minutes (e.g., 40 minutes), the process returns to step S111. This process continues in sequence. The set duration is positively correlated with the value of the charging failure flag in the high-voltage residential energy storage system, indicating that the probability of successful charging in a short period of time may be low. Therefore, the set duration is appropriately increased. As the number of consecutive charging failures increases, the set duration of the interval also increases to avoid increased power consumption due to frequent operations. Furthermore, after the charging failure flag reaches a preset value N, such as 6, the set duration is fixed at N*M. Even if the charging failure flag accumulates to 7, the system still returns to S111 after an interval of N*M.

[0050] Optionally, if the charging failure of the high-voltage residential energy storage system is continuous, the battery voltage will continue to decrease. If the voltage of at least one cell in at least one battery cluster is less than the power-down threshold (e.g., 2.5V, which can be set according to the actual situation), in order to prevent the battery from continuing to consume power, the circuit breaker (i.e., the second switch K2) will be opened to power down the system.

[0051] Optionally, after obtaining the current at the positive or negative terminal and determining that the high-voltage residential energy storage system has been successfully charged based on the current, the process also includes: When the voltage of each individual cell in each battery cluster is greater than the second set threshold, or when the voltage of each individual cell in each battery cluster increases by a preset amount, a strong charging stop signal is sent to the energy storage inverter so that the energy storage inverter controls the residential high-voltage residential energy storage system to exit the strong charging mode.

[0052] The second set threshold represents the minimum voltage of a single battery cell when the high-voltage residential energy storage system can exit the intensive charging mode, and the preset capacity represents the minimum amount of charge that a single battery cell must have gained since the start of intensive charging when the high-voltage residential energy storage system can exit the intensive charging mode. Optionally, the second set threshold can be equal to 3.15V, and the preset capacity can be equal to 5% of the full capacity. Then, when the voltage of each battery cell in each battery cluster is greater than 3.15V, or when the cumulative voltage of each battery cell in each battery cluster reaches 5% of the full capacity, the high-voltage residential energy storage system exits the intensive charging mode, stops charging, and enters the normal charging and discharging mode.

[0053] Optionally, during the process of the high-voltage residential energy storage system entering the strong charging mode, the host will calculate the charging current and charging time based on the current voltage, temperature, capacity, and energy storage inverter parameters of each battery cell, and interact with the client to promptly inform the user of the duration of power outage.

[0054] Figure 4 A flowchart of another control method for a high-voltage residential energy storage system provided in an embodiment of the present invention is shown below. Figure 4 ,refer to Figure 4 The method includes: S112: Determine the parallel operation sequence of each battery cluster according to the order of their voltages from smallest to largest; where battery clusters with the same voltage are paralleled simultaneously.

[0055] The order of battery cluster voltage from smallest to largest is determined as the parallel operation sequence of the battery clusters.

[0056] S122: Controls the closing of the switching assembly of the first battery cluster that needs to be paralleled, so as to complete the paralleling.

[0057] Specifically, the switch component corresponding to the battery cluster with the lowest control voltage is closed, so that the battery cluster with the lowest voltage can be directly connected in parallel.

[0058] For each battery cluster requiring parallel operation, except for the first one, perform the following steps: S132: Is the difference between the voltage of the battery cluster that needs to be connected in parallel and the average voltage of all battery clusters that have been connected in parallel greater than the parallel difference threshold? If yes, execute S142; otherwise, execute S162.

[0059] The parallel operation difference threshold is the minimum voltage difference required to initiate a forced charging operation on a paralleled battery cluster. For example, the parallel operation difference threshold could be 4V. If the i-th battery cluster is the one currently requiring parallel operation, and the difference between the voltage of the i-th battery cluster and the average voltage (i.e., bus voltage) of all battery clusters from the i-th to the (i-1)-th battery clusters is greater than 4V, it indicates a significant voltage difference. In this case, all battery clusters from the i-th to the (i-1)-th battery clusters must be charged to the same voltage as the i-th battery cluster before the parallel operation on the i-th battery cluster is performed. If the difference between the voltage of the i-th battery cluster and the average voltage (bus voltage) of all battery clusters from the i-th to the (i-1)-th battery clusters is less than or equal to 4V, it indicates a small voltage difference, and the parallel operation on the i-th battery cluster can be performed directly. In other words, if the difference between the voltage of the battery cluster that needs to be paralleled and the bus voltage is greater than the difference threshold, then S142 is executed; if the difference between the voltage of the battery cluster that needs to be paralleled and the bus voltage is less than or equal to the difference threshold, then 162 is executed to directly control the battery cluster that needs to be paralleled to be paralleled.

[0060] S142: Generate a strong charging parallel operation signal and send it to the energy storage inverter so that the energy storage inverter controls the high-voltage residential system to enter the strong charging mode, and charges the battery clusters that have been connected in the strong charging mode.

[0061] For example, assuming that the battery cluster that needs to be paralleled is the third battery cluster that needs to be paralleled, after the second battery cluster that needs to be paralleled is completed, a strong charging parallel signal is generated to the energy storage inverter 1. After receiving the strong charging parallel signal, the energy storage inverter 1 controls the high-voltage residential system to enter the strong charging mode. In the strong charging mode, the energy storage inverter 1 charges the paralleled battery clusters, namely the first paralleled battery cluster and the second paralleled battery cluster.

[0062] Since the battery clusters after parallel operation have already had their corresponding switch components closed, there is no need to close them again.

[0063] S152: When all the battery clusters that have been connected to the grid are charged to the voltage of the next battery cluster that needs to be connected to the grid, a strong charging stop signal is sent to the energy storage inverter so that the energy storage inverter 1 controls the high-voltage residential energy storage system to exit the strong charging mode, so that the energy storage inverter stops charging the battery clusters and controls the switch component corresponding to the battery cluster that needs to be connected to the grid to close.

[0064] When the first and second battery clusters are charged to the voltage of the third battery cluster that needs to be paralleled, a strong charging stop signal is sent to the energy storage inverter so that the energy storage inverter stops outputting charging voltage, the charging of the battery clusters stops, and then the host controls the corresponding switch component of the third battery cluster that needs to be paralleled to close.

[0065] S162: Controls the closing of the switch component corresponding to the battery cluster that needs to be paralleled, so as to complete the paralleling.

[0066] Control the closing of the switch component corresponding to the battery cluster that needs to be paralleled, so as to complete the paralleling of the battery cluster that needs to be paralleled.

[0067] S172: Have all battery clusters completed parallel operation? If yes, proceed to S182; otherwise, return to S132.

[0068] S132 and S162 are executed repeatedly until all battery clusters are connected in parallel.

[0069] All parallel battery clusters simultaneously begin high-pressure charging. Since the initial voltage and charging current of each cluster are identical upon completion of parallel charging, they charge to the voltage of the next cluster requiring parallel charging at approximately the same time. At this point, the main unit sends a high-pressure charging stop signal to the energy storage inverter. Upon receiving this signal, the inverter exits high-pressure charging mode and stops outputting charging current and voltage, ceasing charging of the parallel battery clusters.

[0070] Figure 5 This is a block diagram of the high-voltage residential energy storage system during parallel operation, provided in an embodiment of the present invention. Figure 5 The example illustrates n battery management systems (BMS) from BMS1 to BMSn. For instance, the voltages of the battery clusters corresponding to BMS1 through BMSn increase sequentially, and the voltage difference between adjacent battery clusters is greater than the parallel operation difference threshold. Therefore, during parallel operation, the battery clusters corresponding to BMS1 through BMSn are controlled to operate in parallel sequentially. The battery clusters corresponding to BMS1 through BMSn are denoted as the first battery cluster to the nth battery cluster. During parallel operation, the host controls the switch component corresponding to the first battery cluster 9-1 to close. Then, a strong charging parallel operation signal is generated and sent to the energy storage inverter, causing the energy storage inverter 1 to control the high-voltage residential energy storage system to enter strong charging mode, enabling the energy storage inverter to charge the first battery cluster 9-1. When the voltage of the second battery cluster 9-2 is reached, the energy storage inverter 1 stops outputting charging voltage. Then, the switch component of the second battery cluster 9-2 is controlled to close, realizing the parallel operation of the second battery cluster 9-2, and so on, until the nth battery cluster 9-n is paralleled.

[0071] S182: When it is determined that at least one battery cluster has an over-discharge protection fault, after all switching components are closed, a strong charging signal is generated and sent to the energy storage inverter so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each of the battery clusters in the strong charging mode.

[0072] S192: Obtain the current at the positive or negative terminal and determine whether the high-voltage residential energy storage system has failed to charge based on the current. If not, execute S202; if yes, execute S212.

[0073] S202: Clear the charging failure flag.

[0074] S212: Controls each switching component to disconnect and increments the charging failure flag by 1.

[0075] S222: Determine whether the value of the failure flag has reached the preset value. If yes, execute S232, i.e., after an interval of the preset value, return to step S182. If no, execute S242, i.e., after an interval of a set time, return to step S182. The set time is positively correlated with the current value of the charging failure flag.

[0076] To address the issue of excessive inter-cluster voltage differences preventing other clusters from being paralleled, the system initiates paralleling operations starting with the cluster with the lowest total voltage. If other clusters cannot be paralleled due to excessive voltage differences between themselves and the bus (between the positive and negative terminals), the system first initiates a forced charging operation, sending a forced charging signal to the energy storage inverter to charge the system. When the bus voltage equals the total voltage of the next unparalleled cluster, the next unparalleled cluster is then paralleled, and so on, until all clusters are successfully paralleled. Paralleling is performed sequentially according to the cluster voltage from lowest to highest to avoid the influence of circulating current.

[0077] Optionally, after all battery clusters are connected in parallel, the voltage conversion module (DCDC) corresponding to each battery cluster draws power from the battery cluster and outputs the converted voltage (12V or 24V) to the battery management system corresponding to that battery cluster, specifically the battery control unit 31, to power it on. After all battery management systems are powered on, they include: Step a1: For any battery cluster, when the host determines that the battery cluster does not have an over-discharge protection fault or any preset fault, it controls the battery management system corresponding to the battery cluster to enter shutdown mode. Alternatively, it enters standby mode.

[0078] The preset faults are those that affect the closing of the switch assembly, excluding over-discharge protection faults, such as low battery temperature, high battery temperature, and insulation faults. Under the preset faults, the switch assembly is prohibited from closing.

[0079] Step a2: When the charging and discharging signal output by the energy storage inverter is received, control the corresponding switching component of each battery management system in standby mode to close to enter the normal operation mode.

[0080] When there is no fault in the battery cluster, the host controls the battery management system corresponding to the battery cluster to enter standby mode. When the host receives a charge / discharge signal, it controls the switch component corresponding to the battery management system in standby mode to close so that the battery cluster enters normal operation mode and performs charging or discharging operations according to user needs.

[0081] Optionally, based on the current of the battery cluster corresponding to any closed switch component, if the battery cluster has not been charged or discharged for a first set time, and at the same time the voltage of at least one battery cell in the battery cluster is less than a first set threshold and the average voltage of all battery cells is less than a second set threshold, the battery management system corresponding to the battery cluster is controlled to enter a first sleep mode; the second set threshold is greater than the first set threshold.

[0082] For any given battery cluster, if the corresponding switch component is detected to be closed, and the cluster remains uncharged and undischarged for a first set duration (e.g., 30 minutes), and then for a third set duration (e.g., 20 seconds), at least one battery cell in the cluster has a voltage lower than a first set threshold, and the average voltage of all battery cells is lower than a second set threshold, then the cluster voltage is considered too low and cannot be charged. Therefore, the battery management system must enter a first sleep mode to reduce further voltage consumption. The average battery cell voltage falling below the battery cell voltage recovery threshold (i.e., the second set threshold 3.15V) is used to prevent charging during the longest possible sleep period if the cluster fails to resume normal data acquisition in time.

[0083] Optionally, when the switching component corresponding to any battery cluster remains disconnected for a second set duration, and the voltage of at least one battery cell in the battery components of the battery cluster is less than a first set threshold, the battery management system corresponding to the battery cluster is controlled to enter a second sleep mode.

[0084] If, when the switching assembly remains open for a second set duration (e.g., 30 minutes), and the voltage of at least one cell in the battery cluster corresponding to the switching assembly remains below a first set threshold for a fourth set duration (e.g., 20 seconds), the battery management system corresponding to that battery cluster will enter a second sleep mode to reduce power consumption of the battery cluster. Since the contactor is open, overcharging of individual cells is not considered at this time; however, if a system disconnection fault occurs, it will enter sleep mode, and a quick alarm clearing will allow for manual system reset for rapid recovery.

[0085] Whether in the first sleep mode or the second sleep mode, within one working cycle, the battery management system that controls the entry into sleep mode sequentially collects the voltage of each battery cell in each battery component of the battery cluster corresponding to the battery management system m times at a preset sampling interval.

[0086] In sleep mode, during operation, data is collected using a rapid acquisition method. One working cycle consists of m voltage acquisitions, with one acquisition occurring at a preset sampling interval. After collecting m voltages, the system enters sleep mode and ceases data acquisition. For example, with m equal to 10 acquisitions and a preset sampling interval of 100ms, one working cycle completes the acquisition in 1 second, and the system enters sleep mode for the remaining time, ceasing data acquisition. Note that the voltage and temperature of individual battery cells are not collected at the same time.

[0087] Optionally, the duty cycle corresponding to the first sleep mode is shorter than the duty cycle corresponding to the second sleep mode. For example, the first cycle is equal to 60 seconds and the second cycle is equal to 360 seconds.

[0088] If the conditions for entering the first or second hibernation mode are not met, the current hibernation mode will be automatically exited.

[0089] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0090] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a high-voltage residential energy storage system, characterized in that, The high-voltage residential energy storage system includes: an energy storage inverter, at least one battery cluster, at least one battery management system corresponding to the at least one battery cluster, and at least one switching component corresponding to the at least one battery cluster; the battery cluster includes multiple battery components, and the battery cluster and the corresponding switching component are connected in series between the positive terminal and the negative terminal of the high-voltage residential energy storage system; the battery management system is connected to each battery component in the corresponding battery cluster and the corresponding switching component; the energy storage inverter is also connected to the positive terminal and the negative terminal; any one of the at least one battery management systems is used as a host, and the control method of the high-voltage residential energy storage system is executed by the host; the control method of the high-voltage residential energy storage system includes: When it is determined that at least one battery cluster has an over-discharge protection fault, after all the switching components are closed, a strong charging signal is generated and sent to the energy storage inverter, so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each battery cluster in the strong charging mode; when the voltage of at least one battery cell of at least one battery component in the battery cluster is less than a first set threshold or the charge is less than a first charge threshold, the battery cluster has the over-discharge protection fault. The system acquires the current at the positive or negative terminal and controls each of the switching components to disconnect when the high-voltage residential energy storage system fails to charge, based on the current. After a set interval, the process returns to the step of obtaining the switching status of each switch component when it is determined that at least one battery cluster has an over-discharge protection fault, and controlling the unclosed switch components to close, until all the switch components are closed, until the high-voltage residential energy storage system is successfully charged.

2. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, When it is determined that the high-voltage residential energy storage system has failed to charge based on the current, after controlling each of the switching components to disconnect, the method further includes: incrementing the charging failure flag by 1; After the high-voltage residential energy storage system is successfully charged, the following steps are also included: clearing the charging failure flag bit to zero. The set duration is positively correlated with the current value of the charging failure flag.

3. The control method for a high-voltage residential energy storage system according to claim 2, characterized in that, When the value of the charging failure flag reaches a preset value, the set duration is fixed to a preset value; the preset value is the set duration corresponding to when the value of the charging failure flag is equal to the preset value.

4. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, After obtaining the current at the positive or negative terminal and determining that the high-voltage residential energy storage system has been successfully charged based on the current, the process further includes: If the voltage of each individual battery cell in each battery cluster is greater than the second set threshold, or if the voltage of each individual battery cell in each battery cluster increases by a preset amount, a strong charging stop signal is sent to the energy storage inverter to cause the high-voltage residential energy storage system to exit the strong charging mode.

5. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, The high-voltage residential energy storage system includes at least two battery clusters and at least two battery management systems, with each battery management system except the host acting as a slave. Before generating a strong charging signal and sending it to the energy storage inverter when all the switching components are closed, and after determining that at least one battery cluster has an over-discharge protection fault, so that the energy storage inverter controls the high-voltage residential energy storage system to enter a strong charging mode, and before charging each of the battery clusters in the strong charging mode, the method further includes: The parallel operation sequence of each battery cluster is determined according to the order of their voltages from smallest to largest; battery clusters with the same voltage are paralleled simultaneously. The switch assembly corresponding to the first battery cluster that needs to be paralleled is closed to complete the paralleling process; For each battery cluster that needs to be paralleled except for the first one: when the difference between the voltage of the current battery cluster that needs to be paralleled and the average voltage of all battery clusters that have been paralleled is greater than the paralleling difference threshold, a strong charging paralleling signal is generated and sent to the energy storage inverter, so that the energy storage inverter controls the high-voltage residential system to enter the strong charging mode, and charges the paralleled battery clusters in the strong charging mode. When all the battery clusters that have been connected to the grid are charged to the voltage of the next battery cluster that needs to be connected to the grid, a strong charging stop signal is sent to the energy storage inverter so that the high-voltage residential energy storage system exits the strong charging mode, the energy storage inverter stops charging the battery clusters, and controls the switch components corresponding to the battery cluster that needs to be connected to the grid to close. When the difference between the voltage of the battery cluster that needs to be paralleled and the average voltage of all battery clusters that have been paralleled is less than or equal to the paralleling difference threshold, the switch component corresponding to the battery cluster that needs to be paralleled is controlled to close to complete the paralleling.

6. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, Also includes: For any of the battery clusters, if it is determined that the battery cluster does not have the over-discharge protection fault or any preset fault, the battery management system corresponding to the battery cluster is controlled to enter the shutdown mode. The preset fault is any fault that affects the closing of the switch assembly, other than the over-discharge protection fault. Upon receiving the charge / discharge signal output by the energy storage inverter, the switch component corresponding to each battery management system in the standby mode is controlled to close to enter the normal operation mode.

7. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, Also includes: If the battery cluster has not been charged or discharged for a first set time based on the current of any closed switch component, and at the same time the voltage of at least one battery cell in the battery cluster is less than the first set threshold and the average voltage of all the battery cells is less than the second set threshold, the battery management system corresponding to the battery cluster is controlled to enter a first sleep mode; the second set threshold is greater than the first set threshold.

8. The control method for a high-voltage residential energy storage system according to claim 7, characterized in that, In the first sleep mode, within one working cycle, the battery management system, which is controlled to enter the first sleep mode, sequentially collects the voltage of each battery cell in each battery component of the battery cluster corresponding to the battery management system m times at a preset sampling interval.

9. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, Also includes: When the switching component corresponding to any battery cluster remains disconnected for a second set duration, and the voltage of at least one battery cell in the battery cluster is less than the first set threshold, the battery management system corresponding to the battery cluster is controlled to enter a second sleep mode. In the second sleep mode, within one working cycle, the battery management system, which is controlled to enter the second sleep mode, sequentially collects the voltage of each battery cell in each battery component of the battery cluster corresponding to the battery management system m times at a preset sampling interval.

10. The control method for a high-voltage residential energy storage system according to claim 1, characterized in that, Also includes: When it is determined that the voltage of a single battery cell in at least one battery cluster is greater than the first set threshold and less than the second set threshold, or the charge of at least one battery cell is greater than the first charge threshold and less than the second charge threshold, a strong charging signal is generated and sent to the energy storage inverter after all the switching components are closed, so that the energy storage inverter controls the high-voltage residential energy storage system to enter the strong charging mode and charges each battery cluster in the strong charging mode; the second set threshold is greater than the first set threshold, and the second charge threshold is greater than the first charge threshold.

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