Control method of energy storage system

Abstract

The invention provides a control method of an energy storage system, the energy storage system comprises a plurality of battery clusters, each battery cluster comprises a first half cluster and a second half cluster, the method comprises the following steps: when a target charging instruction for the energy storage system is received, collecting battery information of each battery cluster corresponding to the target charging instruction, the battery information comprises a first voltage value of a first half cluster and a second voltage value of a second half cluster; according to a first voltage difference value between the first voltage value and the second voltage value, determining a charging strategy corresponding to the target charging instruction for each battery cluster; and charging each battery cluster according to the determined charging strategy corresponding to each battery cluster.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage systems, and in particular to a control method for an energy storage system. Background Art

[0002] In existing technologies, each battery cluster in an energy storage system is connected to an inverter. Due to the inverter drawing power or the battery cluster discharging during energy storage system operation, the battery half-cluster can have asymmetric charge levels, leading to voltage consistency issues across the battery cluster. Furthermore, the energy storage system's long-term charging of the battery cluster in backup mode shortens its lifespan and compromises the safety of the energy storage system. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide at least a control method for an energy storage system, which collects battery information corresponding to the target charging instruction by determining the received target charging instruction, thereby obtaining the half-cluster voltage difference of each battery cluster through the battery information, and determines the charging strategy corresponding to the target charging instruction through the half-cluster voltage difference, and then charges the battery cluster according to the charging strategy, thereby solving the technical problem of poor consistency of battery clusters in the prior art, and achieving the technical effect of reducing the large half-cluster voltage difference and poor consistency in the battery cluster.

[0004] This application mainly includes the following aspects:

[0005] In a first aspect, an embodiment of the present application provides a control method for an energy storage system, wherein the energy storage system includes multiple battery clusters, wherein each battery cluster includes a first half cluster and a second half cluster, and the method includes: upon receiving a target charging instruction for the energy storage system, collecting battery information of each battery cluster corresponding to the target charging instruction, the battery information including a first voltage value of the first half cluster and a second voltage value of the second half cluster; determining a charging strategy for each battery cluster corresponding to the target charging instruction based on a first voltage difference between the first voltage value and the second voltage value; and charging each battery cluster according to the determined charging strategy corresponding to each battery cluster.

[0006] Optionally, determining the charging strategy for each battery cluster corresponding to the target charging instruction based on the first voltage difference between the first voltage value and the second voltage value includes: determining the charging strategy corresponding to the target voltage range by the target voltage range corresponding to the target charging instruction within which the first voltage difference falls.

[0007] Optionally, the target charging instruction includes a first charging instruction for controlling the full charge and standby power of the energy storage system or a second charging instruction for controlling the incomplete charge of the energy storage system, wherein the target voltage range corresponding to the first charging instruction includes a first voltage range or a second voltage range, the upper limit value of the first voltage range is less than the lower limit value of the second voltage range, and the target voltage range corresponding to the second charging instruction includes a third voltage range and a fourth voltage range, and the upper limit value of the third voltage range is less than the lower limit value of the fourth voltage range.

[0008] Optionally, the charging strategy includes at least one charging step. For each charging step in the charging strategy, charging is performed using the charging method corresponding to the charging step. When the preset stop condition corresponding to the charging step is reached, the next charging step after the charging step is executed until each charging step in the charging strategy is completed. The charging method includes: only charging the battery cluster as a whole, or adjusting the order between charging the battery cluster as a whole and charging the target half cluster as a half, where the target half cluster refers to the first half cluster or the second half cluster.

[0009] Optionally, the step of determining the charging strategy for each battery cluster corresponding to the first charging instruction based on the first voltage difference between the first voltage value and the second voltage value includes: determining the first voltage range or the second voltage range into which the first voltage difference of the battery cluster falls; when the first voltage difference falls within the first voltage range, determining the first charging strategy corresponding to the first voltage range; when the first voltage difference falls within the second voltage range, determining the second charging strategy corresponding to the first voltage range.

[0010] Optionally, the first charging strategy includes: after charging the entire battery cluster to a first preset condition, half-cluster charging the target half cluster to the first preset condition; the second charging strategy includes: after charging the half cluster corresponding to the lower voltage value of the first voltage value and the second voltage value to a second preset condition, charging the entire battery cluster to the first preset condition, and then half-cluster charging the target half cluster to the first preset condition, wherein the target half cluster is a second preset half cluster other than the first preset half cluster corresponding to the first preset condition.

[0011] Optionally, each battery cluster includes a plurality of battery cells connected in series, and the first preset condition includes any one of the battery cells reaching a first preset voltage value, or the voltage value of the battery cluster reaches a second preset voltage value. The first preset half cluster corresponding to the battery cell reaching the first preset voltage value refers to the half cluster where the battery cell that reaches the first preset voltage value is located, and the first preset half cluster corresponding to the battery cell that reaches the second preset voltage value refers to the half cluster where the battery cell with the highest voltage value when reaching the second preset voltage value is located. The second preset condition includes the first voltage difference between the first half cluster and the second half cluster reaching a third preset voltage value.

[0012] Optionally, the step of determining the charging strategy for each battery cluster corresponding to the second charging instruction based on the first voltage difference between the first voltage value and the second voltage value includes: determining the third voltage range or the fourth voltage range into which the first voltage difference of the battery cluster falls; when the first voltage difference falls within the third voltage range, determining the third charging strategy corresponding to the first voltage range; when the first voltage difference falls within the fourth voltage range, determining the fourth charging strategy corresponding to the first voltage range.

[0013] Optionally, the third charging strategy includes: charging the entire battery cluster to a third preset condition, and the fourth charging strategy includes: charging the entire battery cluster to a third preset condition after charging half of the cluster corresponding to the lower voltage value of the first voltage value and the second voltage value to the second preset condition.

[0014] Optionally, the second preset condition includes that a first voltage difference between the first half cluster and the second half cluster reaches a third preset voltage value, and the third preset condition includes a preset state of charge threshold.

[0015] Optionally, the battery information also includes the state of charge corresponding to the second charging instruction, and the method also includes: determining whether the state of charge of each battery cluster falls within a preset charging state of charge range; when the state of charge falls within the preset charging state of charge range, determining the charging strategy for each battery cluster corresponding to the second charging instruction based on the first voltage difference between the first voltage value and the second voltage value.

[0016] Optionally, the energy storage system further includes a main contactor and a pre-charge contactor corresponding to each battery cluster. After collecting the battery information of each battery cluster corresponding to the target charging instruction, the method further includes: after controlling the pre-charge contactor corresponding to each battery cluster to close, determining a second voltage difference between every two battery clusters in the multiple battery clusters; based on the second voltage difference between every two battery clusters, determining a target action strategy for the contactor in the energy storage system; and controlling the actions of the main contactor and the pre-charge contactor according to the target action strategy.

[0017] Optionally, a target action strategy for the contactor in the energy storage system is determined by determining a target contactor closing range within which the second voltage difference between each two battery clusters falls, and the target action strategy is used to control the actions and action sequence performed by the main contactor and the pre-charge contactor.

[0018] An embodiment of the present application provides a control method for an energy storage system, wherein the energy storage system includes multiple battery clusters, each of which includes a first half-cluster and a second half-cluster. The method includes: upon receiving a target charging instruction for the energy storage system, collecting battery information for each battery cluster corresponding to the target charging instruction, the battery information including a first voltage value for the first half-cluster and a second voltage value for the second half-cluster; determining a charging strategy for each battery cluster corresponding to the target charging instruction based on a first voltage difference between the first voltage value and the second voltage value; and charging each battery cluster according to the determined charging strategy for each battery cluster. By determining the received target charging instruction, the battery information corresponding to the target charging instruction is collected, thereby obtaining the half-cluster voltage difference for each battery cluster based on the battery information, determining the charging strategy corresponding to the target charging instruction based on the half-cluster voltage difference, and then charging the battery cluster according to the charging strategy. This solves the technical problem of poor consistency of battery clusters in the prior art and achieves the technical effect of reducing the large voltage difference and poor consistency of the half-cluster voltages in the battery cluster.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A flow chart of a method for controlling an energy storage system provided in an embodiment of the present application is shown.

[0022] Figure 2 A flowchart of the steps of determining a charging strategy for each battery cluster corresponding to a first charging instruction based on a first voltage difference between a first voltage value and a second voltage value provided by an embodiment of the present application is shown.

[0023] Figure 3 A flowchart of the steps of determining a charging strategy for each battery cluster corresponding to a second charging instruction based on a first voltage difference between a first voltage value and a second voltage value provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0025] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0026] In the prior art, the positive pole of each battery cluster is connected to a first power transmission line, the negative pole of each battery cluster is connected to a second power transmission line, one end of the inverter is connected to the first power transmission line, and the other end of the inverter is connected to the second power transmission line. The first power transmission line and the second power transmission line are used to output the power of each battery cluster. A target connection terminal is provided in each series-connected battery cell in each battery cluster, and the target connection terminal divides each battery cluster into a first battery cluster and a second battery cluster. Because the inverter draws power from the battery cluster, and the battery cluster discharges during the process of the energy storage system discharging the battery cluster, there is a difference in voltage between the first half of the battery cluster and the second half of the battery cluster, resulting in poor consistency of the battery cluster.

[0027] Based on this, an embodiment of the present application provides a control method for an energy storage system. By determining a received target charging instruction, the method collects battery information corresponding to the target charging instruction, thereby obtaining the half-cluster voltage difference of each battery cluster based on the battery information. The charging strategy corresponding to the target charging instruction is determined based on the half-cluster voltage difference, and the battery cluster is then charged according to the charging strategy. This solves the technical problem of poor consistency of battery clusters in the prior art and achieves the technical effect of reducing the large half-cluster voltage difference and poor consistency in the battery cluster. The details are as follows:

[0028] See also Figure 1 , Figure 1 This is a flow chart of a control method for an energy storage system provided in an embodiment of the present application. Figure 1 As shown, the control method of the energy storage system provided in the embodiment of the present application includes the following steps:

[0029] S101: upon receiving a target charging instruction for the energy storage system, collecting battery information of each battery cluster corresponding to the target charging instruction.

[0030] The energy storage system includes multiple battery clusters and inverters. The inverter is used to convert the direct current (DC) power of the multiple battery clusters into alternating current (AC). Each battery cluster includes multiple battery cells connected in series. The connection between the inverter and each battery cluster divides each battery cluster into a first half cluster and a second half cluster. The first half cluster and the second half cluster have the same number of battery cells.

[0031] The battery information includes a first voltage value of the first half of the battery cell and a second voltage value of the second half of the battery cell. The battery information also includes the voltage value of the battery cell. This facilitates detecting the correctness of the collected first and second voltage values ​​using the voltage value of the battery cell. This prevents charging if the first and second voltage values ​​are abnormal.

[0032] The target charging instruction includes a first charging instruction for controlling the energy storage system to be fully charged or a second charging instruction for controlling the energy storage system to be not fully charged. The first charging instruction is used to instruct each battery cluster to be fully charged so that the energy storage system can output electric energy to the mains. The second charging instruction is used to instruct each battery cluster to be partially charged so that the energy storage system can supply power to the inverter when it is in a standby state without supplying electric energy to the mains, and the battery cluster being in a partially charged state will increase the service life of the battery cluster. Exemplarily, the second charging instruction is used to control the electric energy of each battery cluster to be charged to a half-charged state.

[0033] The energy storage system also includes a main contactor and a pre-charge contactor corresponding to each battery cluster. After collecting battery information of each battery cluster corresponding to the target charging instruction, the method also includes: after controlling the pre-charge contactor corresponding to each battery cluster to close, determining a second voltage difference between every two battery clusters in the multiple battery clusters; based on the second voltage difference between every two battery clusters, determining a target action strategy for the contactor in the energy storage system; and controlling the actions of the main contactor and the pre-charge contactor according to the target action strategy.

[0034] Before controlling the pre-charge contactor corresponding to each battery cluster to close, the method further includes: performing a power-on test on each battery cluster, and controlling the pre-charge contactor corresponding to each battery cluster to close if no alarm is detected during the power-on test. The power-on test may detect information such as a second voltage difference between each two battery clusters.

[0035] The main contactor corresponding to each battery cluster includes a main positive contactor and a main negative contactor, and the pre-charge contactor corresponding to each battery cluster includes a positive pre-charge contactor and a negative pre-charge contactor. For each battery cluster, the positive pre-charge contactor corresponding to the battery cluster is connected in series with a preset resistor and then connected in parallel with the main positive contactor. The negative pre-charge contactor corresponding to the battery cluster is connected in series with a preset resistor and then connected in parallel with the main negative contactor. The positive pre-charge contactor is set between the positive electrode of the battery cluster and the inverter, and the negative pre-charge contactor is set between the negative electrode of the battery cluster and the inverter.

[0036] A target action strategy for the contactor in the energy storage system is determined in the following manner: a target action strategy for the contactor in the energy storage system is determined by a target contactor closing range within which the second voltage difference between each two battery clusters falls, and the target action strategy is used to control the actions and action sequence performed by the main contactor and the pre-charge contactor.

[0037] The target contactor closing range includes a first contactor closing range or a second contactor closing range, the upper limit value of the first contactor closing range is less than the lower limit value of the second contactor closing range, wherein the target action strategy includes: a first action strategy corresponding to when the second voltage difference between each two battery clusters falls within the first contactor closing range, or a second action strategy corresponding to when any one of the second voltage difference values ​​falls within the second contactor closing range.

[0038] The first action strategy includes: after closing the main contactor of the first battery cluster with the highest voltage value and disconnecting the pre-charge contactor of the first battery cluster, closing the main contactor of the second battery cluster other than the first battery cluster and disconnecting the pre-charge contactor of the second battery cluster. The second action strategy includes: after closing the main contactor of the first battery cluster with the highest voltage value and disconnecting the pre-charge contactor of the first battery cluster, determining whether the second voltage difference falls within the closing range of the first contactor, and closing the main contactor of the second battery cluster other than the first battery cluster and disconnecting the pre-charge contactor of the second battery cluster when the second voltage difference falls within the closing range of the first contactor.

[0039] That is, after collecting battery information of each battery cluster corresponding to the target charging instruction, controlling the pre-charge contactor corresponding to each battery cluster to close; calculating the difference between the voltage values ​​of each two battery clusters in the plurality of battery clusters as a second voltage difference; when the second voltage difference between each two battery clusters falls within the first contactor closing range, after closing the main contactor of the first battery cluster with the highest voltage value, disconnecting the pre-charge contactor of the first battery cluster, then closing the main contactor of the second battery cluster other than the first battery cluster, and finally disconnecting the pre-charge contactor of the second battery cluster; when any of the second voltage differences falls within the second contactor closing range, first closing the main contactor of the first battery cluster with the highest voltage value, and disconnecting the pre-charge contactor of the first battery cluster, so that the electric energy of the first battery cluster is transmitted to the second battery cluster other than the first battery cluster, thereby reducing the second voltage difference between the battery clusters; determining whether the second voltage difference falls within the first contactor closing range, closing the main contactor of the second battery cluster other than the first battery cluster when the second voltage difference falls within the first contactor closing range, and disconnecting the pre-charge contactor of the second battery cluster.

[0040] The main contactor corresponding to the first battery cluster with the highest voltage is closed first, followed by the main contactors of the second battery clusters excluding the first, to reduce the circulating current between the battery clusters and keep it within an acceptable range. In the second action strategy, the main contactor corresponding to the first battery cluster is closed first. After the second voltage difference between each two battery clusters falls within the first contactor closing range, the main contactors of the second battery clusters excluding the first are closed. This allows the first battery cluster to pre-charge the second battery cluster, thus reducing the voltage difference between the battery clusters.

[0041] The method also includes: when any of the second voltage difference values ​​is greater than the upper limit of the second contactor closing range, the pre-charge contactors corresponding to each battery cluster are disconnected in sequence, and the battery clusters are not clustered. The solution of the present application is applied to a battery management system. After the main contactors of each battery cluster are closed and the pre-charge contactors are disconnected, the battery management system sends a control signal to the inverter not to turn on the inverter. Before the main contactors of each battery cluster are closed and the pre-charge contactors are disconnected, the battery management system sends a control signal to the inverter to turn on the inverter. The battery management system can be implemented by adding a flag bit to indicate whether to turn on the inverter when performing protocol communication with the inverter.

[0042] S102: Determine a charging strategy for each battery cluster corresponding to the target charging instruction according to a first voltage difference between the first voltage value and the second voltage value.

[0043] Determining the charging strategy for each battery cluster corresponding to the target charging instruction based on the first voltage difference between the first voltage value and the second voltage value includes: determining the charging strategy corresponding to the target voltage range by determining the target voltage range corresponding to the target charging instruction within which the first voltage difference falls.

[0044] That is, a charging strategy corresponding to the voltage range is determined based on the voltage range of the first voltage difference of each battery cluster. The charging strategy is used to reduce the first voltage difference of each battery cluster to improve the consistency of the battery cluster and reduce the charging time.

[0045] Among them, the target voltage range corresponding to the first charging instruction includes the first voltage range or the second voltage range, the upper limit value of the first voltage range is less than the lower limit value of the second voltage range, and the target voltage range corresponding to the second charging instruction includes the third voltage range and the fourth voltage range, and the upper limit value of the third voltage range is less than the lower limit value of the fourth voltage range.

[0046] The first and second voltage ranges are divided by a first preset half-cluster voltage difference within the battery cluster. A voltage range less than or equal to the first preset half-cluster voltage difference is defined as the first voltage range, while a voltage range greater than the first preset half-cluster voltage difference is defined as the second voltage range. The first preset half-cluster voltage difference is the allowable half-cluster voltage difference during standby operation. The third and fourth voltage ranges are divided by a second preset half-cluster voltage difference within the battery cluster. A voltage range less than or equal to the second preset half-cluster voltage difference is defined as the third voltage range, while a voltage range greater than the second preset half-cluster voltage difference is defined as the fourth voltage range. The second preset half-cluster voltage difference is the allowable half-cluster voltage difference during standby operation.

[0047] The charging strategy includes at least one charging step. For each charging step in the charging strategy, charging is performed using the charging method corresponding to the charging step. When a preset stop condition corresponding to the charging step is reached, the next charging step after the charging step is executed until each charging step in the charging strategy is completed. The charging method includes: only charging the battery cluster as a whole, or adjusting the order between charging the battery cluster as a whole and charging the target half cluster as a half, where the target half cluster refers to the first half cluster or the second half cluster.

[0048] The charging voltage of the whole cluster charging is the preset charging voltage, and the charging current is the preset charging current; the charging voltage of the half cluster charging is half of the preset charging voltage, and the charging current is half of the preset charging current.

[0049] The step of determining the charging strategy for each battery cluster corresponding to the first charging instruction based on the first voltage difference between the first voltage value and the second voltage value includes: determining the first voltage range or the second voltage range within which the first voltage difference of the battery cluster falls; when the first voltage difference falls within the first voltage range, determining the first charging strategy corresponding to the first voltage range; when the first voltage difference falls within the second voltage range, determining the second charging strategy corresponding to the first voltage range.

[0050] That is to say, determine whether the first voltage difference is less than or equal to the first preset half-cluster voltage difference; when the first voltage difference is less than or equal to the first preset half-cluster voltage difference, determine the first charging strategy corresponding to the first voltage range; when the first voltage difference falls within the second voltage range, determine the second charging strategy corresponding to the first voltage range.

[0051] The first charging strategy includes: after charging the entire battery cluster to a first preset condition, half-cluster charging the target half cluster to the first preset condition; the second charging strategy includes: after charging the half cluster corresponding to the lower voltage value of the first voltage value and the second voltage value to a second preset condition, charging the entire battery cluster to the first preset condition, and then half-cluster charging the target half cluster to the first preset condition, wherein the target half cluster is a second preset half cluster other than the first preset half cluster corresponding to the first preset condition.

[0052] In other words, the first charging strategy includes a first charging step and a second charging step. The first charging step involves charging the entire battery cluster to a first preset condition, while the second charging step involves charging the target half cluster to the first preset condition. Charging the entire cluster first and then the half cluster reduces the first voltage difference across the battery cluster, thereby improving its consistency. The first preset condition is used to stop charging.

[0053] The second charging strategy includes a third charging step, a fourth charging step, and a fifth charging step. The third charging step involves half-cluster charging of the low-voltage half-cluster to a third preset condition. The fourth charging step involves charging the entire battery cluster to a first preset condition. The fifth charging step involves half-cluster charging of the target half-cluster to the first preset condition. Half-cluster charging is performed first, followed by full-cluster charging, and finally half-cluster charging. The first half-cluster charging allows for the final half-cluster charging to take place.

[0054] Regardless of whether the first or second charging strategy is used, the battery cluster's state of charge is calibrated to 100% after the entire cluster is charged to the first preset condition. After the first or second charging strategy is executed, the energy storage system begins to prohibit charging. This prohibition can be lifted when the energy storage system's discharge capacity reaches 5%, or when the voltage of the battery cell with the highest voltage value falls below the first preset voltage value. After the prohibition is lifted, step S101 can be re-executed to recharge the battery cluster.

[0055] Each battery cluster includes a plurality of battery cells connected in series. The first preset condition includes that any one of the battery cells reaches a first preset voltage value, or that the voltage value of the battery cluster reaches a second preset voltage value. The first preset half cluster corresponding to the battery cell that reaches the first preset voltage value refers to the half cluster where the battery cell that reaches the first preset voltage value is located. The first preset half cluster corresponding to the battery cell that reaches the second preset voltage value refers to the half cluster where the battery cell with the highest voltage value when reaching the second preset voltage value is located. The second preset condition includes that the first voltage difference between the first half cluster and the second half cluster reaches a third preset voltage value.

[0056] For example, see Figure 2 , Figure 2 The flowchart of the steps of determining the charging strategy for each battery cluster corresponding to the first charging instruction according to the first voltage difference between the first voltage value and the second voltage value provided in the embodiment of the present application. Figure 2 As shown:

[0057] S201: Determine whether the first voltage difference of the battery cluster is less than or equal to a first preset half-cluster voltage difference.

[0058] S202: After charging the entire battery cluster to a first preset condition, charging the target half cluster to the first preset condition.

[0059] That is to say, for each battery cluster, when the first voltage difference of the battery cluster is less than or equal to the first preset half-cluster voltage difference, the entire battery cluster is charged; it is determined that any battery cell in the battery cluster reaches the first preset voltage value or the voltage value of the battery cluster reaches the second preset voltage value; when any battery cell in the battery cluster reaches the first preset voltage value, the other half cluster outside the half cluster where the battery cell that reaches the first preset voltage value is located is used as the target half cluster, and the target half cluster is half-cluster charged. When any battery cell in the target half cluster reaches the first preset voltage value or the voltage value of the battery cluster reaches the second preset voltage value again, the charging of the battery cluster is stopped; when the voltage value of the battery cluster reaches the second preset voltage value, the other half cluster outside the half cluster where the battery cell with the highest voltage value that reaches the second preset voltage value is located is used as the target half cluster, and the target half cluster is half-cluster charged. When any battery cell in the target half cluster reaches the first preset voltage value or the voltage value of the battery cluster reaches the second preset voltage value again, the charging of the battery cluster is stopped.

[0060] S203: Determine a second charging strategy corresponding to the first voltage range.

[0061] That is to say, for each battery cluster, when the first voltage difference of the battery cluster is greater than the first preset half-cluster voltage difference, the half-cluster corresponding to the lower voltage value of the first voltage value and the second voltage value is half-charged until the first voltage difference reaches the third preset voltage value, and then the battery cluster is fully charged to determine whether any cell in the battery cluster reaches the first preset voltage value or the voltage value of the battery cluster reaches the second preset voltage value; when any cell in the battery cluster reaches the first preset voltage value, the other half-cluster other than the half-cluster where the cell that reaches the first preset voltage value is located is used as the target A target half cluster is designated, and half-cluster charging is performed on the target half cluster. When any battery cell in the target half cluster reaches a first preset voltage value or the voltage value of the battery cluster reaches a second preset voltage value again, charging of the battery cluster is stopped. When the voltage value of the battery cluster reaches the second preset voltage value, another half cluster other than the half cluster where the battery cell with the highest voltage value that reaches the second preset voltage value is located is designated as the target half cluster, and half-cluster charging is performed on the target half cluster. When any battery cell in the target half cluster reaches the first preset voltage value or the voltage value of the battery cluster reaches the second preset voltage value again, charging of the battery cluster is stopped.

[0062] After each battery cluster in the energy storage system has completed full backup charging, it enters a fully charged, ready-to-discharge state. It can output power in response to the power controller, or, in the event of a utility power outage, to meet off-grid power requirements. During this power output, the main contactors of each battery cluster remain closed to ensure power is available to the load. If any battery cluster's voltage, current, or other battery information indicates an alarm, the battery management system sends a disable command to the inverter, halting battery-side discharge and disconnecting the battery cluster's main contactors.

[0063] The battery information also includes the state of charge corresponding to the second charging instruction, and the method also includes: determining whether the state of charge of each battery cluster falls within a preset charging state of charge range; when the state of charge falls within the preset charging state of charge range, determining the charging strategy for each battery cluster corresponding to the second charging instruction based on the first voltage difference between the first voltage value and the second voltage value.

[0064] That is, when the second charging instruction is received, the state of charge of each battery cluster also needs to be collected. For each battery cluster, when the state of charge of the battery cluster falls within a preset charging state of charge range, a charging strategy corresponding to the second charging instruction for each battery cluster is determined based on the first voltage difference between the first voltage value and the second voltage value; when the state of charge of the battery cluster does not fall within the preset charging state of charge range, the battery cluster is not charged.

[0065] The preset charging SOC range refers to a SOC range that is less than a preset minimum SOC value. That is, for each battery cluster, when the SOC of the battery cluster is less than the preset minimum SOC value, a charging strategy corresponding to the second charging instruction for each battery cluster is determined based on the first voltage difference between the first voltage value and the second voltage value. When the SOC of the battery cluster is greater than or equal to the preset minimum SOC value, the battery cluster is not charged.

[0066] The steps of determining the charging strategy for each battery cluster corresponding to the second charging instruction based on the first voltage difference between the first voltage value and the second voltage value include: determining the third voltage range or the fourth voltage range into which the first voltage difference of the battery cluster falls; when the first voltage difference falls within the third voltage range, determining the third charging strategy corresponding to the first voltage range; when the first voltage difference falls within the fourth voltage range, determining the fourth charging strategy corresponding to the first voltage range.

[0067] The third charging strategy includes: charging the entire battery cluster to a third preset condition. The fourth charging strategy includes: charging the half cluster corresponding to the lower voltage value of the first voltage value and the second voltage value to a second preset condition, and then charging the entire battery cluster to a third preset condition.

[0068] The second preset condition includes that a first voltage difference between the first half cluster and the second half cluster reaches a third preset voltage value, and the third preset condition includes a preset state of charge threshold.

[0069] For example, see Figure 3 , Figure 3 The flowchart of the steps of determining the charging strategy for each battery cluster corresponding to the second charging instruction according to the first voltage difference between the first voltage value and the second voltage value provided in the embodiment of the present application. Figure 3 As shown:

[0070] S301: Determine whether the first voltage difference of the battery cluster is less than or equal to a second preset half-cluster voltage difference.

[0071] S302: Charge the entire battery cluster until the state of charge of the battery cluster is greater than or equal to a preset state of charge threshold.

[0072] That is, for each battery cluster, when the first voltage difference of the battery cluster is less than or equal to the second preset half-cluster voltage difference, the battery cluster is fully charged until the state of charge of the battery cluster is greater than or equal to the preset state of charge threshold.

[0073] S303: After half-cluster charging of the half battery cluster corresponding to the lower voltage value between the first voltage value and the second voltage value until the first voltage difference reaches a third preset voltage value, the entire battery cluster is charged until the state of charge of the battery cluster is greater than or equal to a preset state of charge threshold.

[0074] That is to say, for each battery cluster, when the first voltage difference of the battery cluster is greater than the second preset half-cluster voltage difference, the half cluster corresponding to the lower voltage value between the first voltage value and the second voltage value is half-charged until the first voltage difference reaches the third preset voltage value, and then the battery cluster is fully charged until the charge state of the battery cluster is greater than or equal to the preset charge state threshold, and then charging of the battery cluster is stopped.

[0075] Furthermore, when the energy storage system is continuously in the half-power standby state, the state of charge of each battery cluster is continuously collected, so that when the state of charge of any battery cluster is less than a preset minimum state of charge value, the battery cluster is charged.

[0076] S103: charging each battery cluster according to the determined charging strategy corresponding to each battery cluster.

[0077] Then, each battery cluster is charged according to the charging strategy, and charging is stopped when the last charging step in the charging strategy reaches the corresponding preset stop condition.

[0078] Furthermore, the present application can effectively solve the problem of lithium battery cell voltage consistency caused by uneven power consumption of the push-type inverter: when the voltage difference between the upper and lower half clusters is small, the method of first charging the whole cluster and then charging the half cluster can be adopted, which can effectively avoid the low energy storage problem caused by direct charging of the whole cluster, ensure that the voltage difference of the lithium battery cells of the system is small after full charging, and the DC side can store more electricity; when the voltage difference between the upper and lower half clusters is large, the control method of first charging the half cluster, charging the whole cluster, and then charging the half cluster can be adopted. At this time, the phenomenon of worse consistency between the upper and lower half clusters can be effectively reduced, so that the voltage difference between the upper and lower half clusters of the system is maintained within a certain range, which can ensure more electricity. In addition, the present application proposes a control standby mode of full-charge operation and half-charge static state. When the system needs to be used, the full-charge operation control strategy is executed. When the system does not need to be used, the half-charge standby control mode is entered to avoid the battery cells being in a full-charge state for a long time, and to prevent the battery cells from being in a high-activity state for a long time, which causes expansion, safety and life problems.

[0079] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0080] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of the solution of this embodiment according to actual needs.

[0081] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0082] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0083] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes a plurality of battery clusters, wherein each battery cluster includes a first half cluster and a second half cluster, and the method includes: Upon receiving a target charging instruction for the energy storage system, collecting battery information of each battery cluster corresponding to the target charging instruction, the battery information including a first voltage value of a first half cluster and a second voltage value of a second half cluster; determining a charging strategy for each battery cluster corresponding to the target charging instruction based on a first voltage difference between the first voltage value and the second voltage value; Each battery cluster is charged according to the determined charging strategy corresponding to each battery cluster.

2. The method according to claim 1, characterized in that The determining, based on a first voltage difference between the first voltage value and the second voltage value, a charging strategy for each battery cluster corresponding to the target charging instruction includes: The charging strategy corresponding to the target voltage range is determined based on the target voltage range corresponding to the target charging instruction within which the first voltage difference falls.

3. The method according to claim 2, characterized in that The target charging instruction includes a first charging instruction for controlling the energy storage system to be fully charged or a second charging instruction for controlling the energy storage system to be not fully charged. Among them, the target voltage range corresponding to the first charging instruction includes the first voltage range or the second voltage range, the upper limit value of the first voltage range is less than the lower limit value of the second voltage range, and the target voltage range corresponding to the second charging instruction includes the third voltage range and the fourth voltage range, and the upper limit value of the third voltage range is less than the lower limit value of the fourth voltage range.

4. The method according to claim 3, characterized in that The charging strategy includes at least one charging step, For each charging step in the charging strategy, charging is performed using the charging method corresponding to the charging step. When the preset stop condition corresponding to the charging step is reached, the next charging step after the charging step is performed until each charging step in the charging strategy is completed. The charging method includes: charging the entire battery cluster only, or adjusting the order between charging the entire battery cluster and charging the target half cluster, where the target half cluster refers to the first half cluster or the second half cluster.

5. The method according to claim 4, characterized in that The step of determining a charging strategy for each battery cluster corresponding to the first charging instruction according to a first voltage difference between the first voltage value and the second voltage value includes: determining whether the first voltage difference of the battery cluster falls within a first voltage range or a second voltage range; When the first voltage difference falls within the first voltage range, determining a first charging strategy corresponding to the first voltage range, When the first voltage difference falls within the second voltage range, a second charging strategy corresponding to the first voltage range is determined.

6. The method according to claim 5, characterized in that The first charging strategy includes: after charging the entire battery cluster to a first preset condition, charging the target half cluster to a first preset condition, The second charging strategy includes: after half-cluster charging of the half cluster corresponding to the lower voltage value of the first voltage value and the second voltage value to a second preset condition, charging the entire battery cluster to a first preset condition, and then half-cluster charging of the target half cluster to the first preset condition. The target half-cluster is a second preset half-cluster other than the first preset half-cluster corresponding to the first preset condition.

7. The method according to claim 6, characterized in that Each battery cluster consists of multiple cells connected in series. The first preset condition includes any battery cell reaching a first preset voltage value, or the voltage value of the battery cluster reaching a second preset voltage value. The first preset half cluster corresponding to the battery cell reaching the first preset voltage value refers to the half cluster where the battery cell reaching the first preset voltage value is located. The first preset half cluster corresponding to the battery cell reaching the second preset voltage value refers to the half cluster where the battery cell having the highest voltage value when reaching the second preset voltage value is located. The second preset condition includes that a first voltage difference between the first half cluster and the second half cluster reaches a third preset voltage value.

8. The method according to claim 4, characterized in that The step of determining a charging strategy for each battery cluster corresponding to the second charging instruction according to a first voltage difference between the first voltage value and the second voltage value includes: determining a third voltage range or a fourth voltage range into which the first voltage difference of the battery cluster falls; When the first voltage difference falls within the third voltage range, determining a third charging strategy corresponding to the first voltage range, When the first voltage difference falls within the fourth voltage range, a fourth charging strategy corresponding to the first voltage range is determined.

9. The method according to claim 8, characterized in that The third charging strategy includes: charging the entire battery cluster to a third preset condition, The fourth charging strategy includes: after half-cluster charging corresponding to the lower voltage value of the first voltage value and the second voltage value to a second preset condition, charging the entire battery cluster to a third preset condition.

10. The method according to claim 9, characterized in that The second preset condition includes that a first voltage difference between the first half cluster and the second half cluster reaches a third preset voltage value, and the third preset condition includes a preset state of charge threshold.

11. The method according to claim 3 or 8, characterized in that The battery information further includes a state of charge corresponding to the second charging instruction, and the method further includes: determining whether the state of charge of each battery cluster falls within a preset state of charge interval; When the state of charge falls within a preset state of charge range, a charging strategy for each battery cluster corresponding to the second charging instruction is determined according to a first voltage difference between the first voltage value and the second voltage value.

12. The method according to any one of claims 1 to 10, characterized in that The energy storage system further includes a main contactor and a pre-charge contactor corresponding to each battery cluster. After collecting battery information of each battery cluster corresponding to the target charging instruction, the method further includes: After controlling the pre-charging contactor corresponding to each battery cluster to be closed, determining a second voltage difference between every two battery clusters in the plurality of battery clusters; determining a target action strategy for a contactor in the energy storage system based on the second voltage difference between each two battery clusters; According to the target action strategy, the main contactor and the pre-charge contactor are controlled to operate.

13. The method according to claim 12, characterized in that The target action strategy for the contactor in the energy storage system is determined by: A target action strategy for the contactor in the energy storage system is determined by determining the target contactor closing range within which the second voltage difference between each two battery clusters falls. The target action strategy is used to control the actions and action sequence performed by the main contactor and the pre-charge contactor.

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