Control method and control device of energy storage system and energy storage system

Abstract

The invention discloses a control method and device of an energy storage system and the energy storage system, and belongs to the technical field of energy storage. The method comprises the following steps: acquiring operation condition data of the energy storage system; under the condition that the operation working condition data meets the preset working condition, the first schedulable power of the first energy storage unit is obtained; under the condition that the first schedulable power is greater than or equal to the required power, controlling the first energy storage unit to operate by taking the required power as a power reference value; wherein the preset working condition comprises at least one of the following items: the temperature of the battery body is less than or equal to a preset temperature threshold; the required power is greater than or equal to a preset power threshold. According to the method, when it is judged that the energy storage system is in the preset low-temperature working condition or high-power working condition, the first energy storage unit comprising the sodium battery is preferentially called to provide power needed by a load or receive charging power, output or charging of the energy storage unit is adjusted according to the actual operation condition, the service life of the battery is prolonged, and the energy storage efficiency is improved. And the overall performance of the energy storage system is obviously improved.

Description

Control methods, control devices, and energy storage systems for energy storage systems Technical Field

[0001] This application belongs to the field of energy storage technology, and in particular relates to a control method, control device and energy storage system for an energy storage system. Background Technology

[0002] Energy storage systems, as key equipment for mitigating fluctuations in renewable energy output and ensuring stable grid operation, primarily utilize lithium-ion and sodium-ion batteries. Additionally, hybrid energy storage systems employing both lithium-ion and sodium-ion batteries are also available.

[0003] Currently, most hybrid energy storage systems use the control strategies of single battery systems (such as fixed power allocation), which lack flexibility and cannot be dynamically adjusted according to actual operating conditions. This can easily lead to a shortened battery life and poor overall performance of the energy storage system. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a control method, control device, and energy storage system for an energy storage system, which can adjust the output of the energy storage unit according to actual operating conditions, thereby helping to extend battery life and significantly improve the overall performance of the energy storage system.

[0005] In a first aspect, this application provides a control method for an energy storage system, the energy storage system comprising at least two energy storage units connected in parallel, the at least two energy storage units being a first energy storage unit comprising a sodium battery and a second energy storage unit comprising a lithium battery, the method comprising: acquiring operating condition data of the energy storage system; acquiring a first dispatchable power of the first energy storage unit when the operating condition data meets preset operating condition conditions; and controlling the first energy storage unit to operate with the demand power as a power reference value when the first dispatchable power is greater than or equal to the demand power; wherein the operating condition data includes temperature data of the energy storage system and the demand power, the temperature data including the battery body temperature, and the preset operating condition conditions including at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; and the demand power is greater than or equal to a preset power threshold.

[0006] According to the control method of the energy storage system of this application, the operating condition data of the energy storage system is acquired in real time, and it is determined whether the operating condition data meets the preset operating condition conditions. When it is determined that the energy storage system is in the preset low temperature condition or high power condition, the first energy storage unit, including the sodium battery, is preferentially called to provide the power required by the load or to receive charging power. If the first dispatchable power is greater than or equal to the demand power, the first energy storage unit is controlled to operate with the demand power as the power reference value. The output or charging of the energy storage unit can be adjusted according to the actual operating conditions, which helps to extend the battery life and significantly improve the overall performance of the energy storage system.

[0007] According to one embodiment of this application, after obtaining the first dispatchable power of the first energy storage unit, the method further includes: when the first dispatchable power is less than the required power, controlling the first energy storage unit to operate with the first dispatchable power as a power reference value, and obtaining the difference power and the second dispatchable power of the second energy storage unit, wherein the difference power is determined based on the required power and the first dispatchable power; when the second dispatchable power is greater than or equal to the difference power, controlling the second energy storage unit to operate with the difference power as a power reference value.

[0008] According to one embodiment of this application, after obtaining the operating condition data of the energy storage system, the method further includes: if the operating condition data does not meet the preset operating condition conditions, determining a first power allocation coefficient for each of the energy storage units based on the operating condition data; determining a power reference value for each of the energy storage units based on the required power and the first power allocation coefficient, and controlling the energy storage units to operate according to the corresponding power reference value.

[0009] According to one embodiment of this application, the operating condition data includes health status data and state of charge data; determining the first power allocation coefficient of each of the energy storage units based on the operating condition data includes: determining the first power allocation coefficient of each of the energy storage units based on the health status data and state of charge data of the first energy storage unit, and the health status data and state of charge data of the second energy storage unit.

[0010] According to one embodiment of this application, the method further includes: controlling the faulty energy storage unit to disconnect from the energy storage system and outputting fault alarm information.

[0011] According to one embodiment of this application, the method of controlling the faulty energy storage unit to disconnect from the energy storage system includes: the faulty energy storage unit disconnecting from the energy storage system and obtaining the sum of the dispatchable power of the remaining energy storage units in the energy storage system; if the sum of the dispatchable power is greater than or equal to the demand power, determining the power reference value of each remaining energy storage unit in the energy storage system based on the demand power and a second power allocation coefficient, and controlling the remaining energy storage units to operate according to the corresponding power reference value; wherein, the second power allocation coefficient is determined based on the dispatchable power of the remaining energy storage units.

[0012] According to one embodiment of this application, the dispatchable power of the energy storage unit is determined by the following steps: determining a first correction coefficient based on the state of charge of the energy storage unit; determining a second correction coefficient based on the health status of the energy storage unit; determining a third correction coefficient based on the ramp rate of the energy storage unit; and determining the dispatchable power of the energy storage unit based on the maximum charge / discharge power of the energy storage unit, the first correction coefficient, the second correction coefficient, and the third correction coefficient.

[0013] According to one embodiment of this application, determining the first correction coefficient based on the state of charge of the energy storage unit includes: when the state of charge of the energy storage unit is within a target charge range, the first correction coefficient is set to a first preset value; or, when the state of charge of the energy storage unit is not within the target charge range, determining the first correction coefficient based on a first mapping relationship between the state of charge and the first correction coefficient, wherein the first correction coefficient is less than the first preset value, and the first mapping relationship includes at least one linear function relationship.

[0014] According to one embodiment of this application, determining the second correction coefficient based on the health state of the energy storage unit includes: when the health state of the energy storage unit is greater than or equal to a second state threshold, the second correction coefficient is set to a second preset value; or, when the health state of the energy storage unit is less than the second state threshold, the second correction coefficient is determined based on a second mapping relationship between the health state and the second correction coefficient, wherein the second correction coefficient is less than the second preset value, and the second mapping relationship includes at least one linear function relationship.

[0015] According to one embodiment of this application, determining the third correction coefficient based on the ramp rate of the energy storage unit includes: when the ramp rate of the energy storage unit is less than or equal to a first rate threshold, the third correction coefficient is set to a third preset value; or, when the ramp rate of the energy storage unit is greater than the first rate threshold, the third correction coefficient is determined based on the first rate threshold and the ramp rate of the energy storage unit, wherein the third correction coefficient is less than the third preset value.

[0016] Secondly, this application provides a control device for an energy storage system, the energy storage system including at least two energy storage units connected in parallel, the at least two energy storage units being a first energy storage unit including a sodium battery and a second energy storage unit including a lithium battery, the device including: an acquisition module for acquiring operating condition data of the energy storage system; a first processing module for acquiring a first dispatchable power of the first energy storage unit when the operating condition data meets preset operating condition conditions; and a second processing module for controlling the first energy storage unit to operate with the demand power as a power reference value when the first dispatchable power is greater than or equal to the demand power; wherein, the operating condition data includes temperature data of the energy storage system and the demand power, the temperature data including the battery body temperature, and the preset operating condition conditions including at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; the demand power is greater than or equal to a preset power threshold.

[0017] Thirdly, this application provides an energy storage system, comprising: at least two energy storage units connected in parallel, the at least two energy storage units being a first energy storage unit including a sodium battery and a second energy storage unit including a lithium battery, each energy storage unit being connected to a corresponding energy storage converter, and the AC sides of the at least two energy storage converters being connected in parallel; and a controller connected to the at least two energy storage units, the controller being used to execute the control method of the energy storage system described in the first aspect.

[0018] Fourthly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the control method of the energy storage system as described in the first aspect above.

[0019] Fifthly, this application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the control method of the energy storage system as described in the first aspect above.

[0020] In a sixth aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the control method for the energy storage system as described in the first aspect above.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which: FIG1 is a flowchart illustrating one of the control methods for an energy storage system provided in an embodiment of this application; FIG2 is a structural schematic diagram illustrating one of the energy storage systems provided in an embodiment of this application; FIG3 is a flowchart illustrating another of the control methods for an energy storage system provided in an embodiment of this application; FIG4 is a flowchart illustrating a third of the control methods for an energy storage system provided in an embodiment of this application; FIG5 is a flowchart illustrating a fourth of the control methods for an energy storage system provided in an embodiment of this application; FIG6 is a structural schematic diagram illustrating the control device for an energy storage system provided in an embodiment of this application; FIG7 is a structural schematic diagram illustrating another of the energy storage systems provided in an embodiment of this application; and FIG8 is a structural schematic diagram illustrating the electronic device provided in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The control method, control device, energy storage system, electronic device, and readable storage medium of the energy storage system provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0026] The energy storage system of this application embodiment includes at least two energy storage units connected in parallel. The at least two energy storage units are divided into a first energy storage unit 710 including a sodium battery and a second energy storage unit 720 including a lithium battery.

[0027] It is understood that the energy storage system includes two or more energy storage units. The energy storage units use sodium batteries or lithium batteries as energy storage media. The energy storage unit including sodium batteries is called the first energy storage unit 710, and the energy storage unit including lithium batteries is called the second energy storage unit 720.

[0028] Among them, lithium batteries are characterized by high energy density and high charge and discharge efficiency, while sodium batteries are characterized by excellent low-temperature performance, low cost, abundant resources, and high safety.

[0029] In practice, the energy storage unit can be a battery cluster, which refers to a battery pack consisting of multiple battery modules, where the battery modules are sodium batteries or lithium batteries.

[0030] The energy storage system in this application embodiment is a lithium-sodium hybrid energy storage structure. By leveraging the complementary advantages of sodium batteries and lithium batteries, the system performance is improved, which can meet the operational requirements of complex application scenarios (such as low-temperature regions and high power fluctuation scenarios).

[0031] The energy storage system adopts a string electrical structure, with each energy storage unit connected to a corresponding energy storage converter. At least two energy storage converters are connected in parallel on their AC sides. Each energy storage converter can independently manage its corresponding energy storage unit, reducing the risk of single-point failure in the energy storage system and improving the power regulation accuracy of the energy storage system.

[0032] In energy storage systems, power storage converters (PCS) can convert direct current to alternating current, optimize the charging and discharging process of energy storage units, extend battery life, and improve system efficiency.

[0033] This application provides a control method for an energy storage system, which can adjust the output of the energy storage unit according to the actual operating conditions, thereby helping to extend the battery life and significantly improve the overall performance of the energy storage system.

[0034] As shown in Figure 1, the control method of the energy storage system includes steps 110, 120 and 130.

[0035] Step 110: Obtain the operating condition data of the energy storage system.

[0036] Among them, operating condition data refers to a set of parameters used to describe the operating status and interaction of the energy storage system. It accurately characterizes the system behavior through quantitative indicators of multiple dimensions, including but not limited to time markers, energy status (such as state of charge and health status), power interaction (such as active power, reactive power and charging / discharging direction), and electrical parameters (such as voltage and current).

[0037] In this embodiment, a data acquisition module (such as various sensors and measurement units) can be deployed in the energy storage system to collect the operating condition data of the energy storage system in real time and accurately reflect the current actual operating status of the energy storage system.

[0038] In some embodiments, operating condition data includes temperature data and power demand of the energy storage system.

[0039] The temperature data of the energy storage system includes real-time temperature values ​​at one or more locations within the system. Temperature sensors can be placed at the locations where temperature needs to be measured (such as the battery itself) to collect the corresponding temperature data.

[0040] In some embodiments, the energy storage system includes battery body temperature, and temperature sensors can be arranged at one or more battery bodies to collect the corresponding temperature data.

[0041] Understandably, in charging mode, the required power is the required charging power; in discharging mode, the required power is the required discharging power. For example, when an energy storage system is connected to a load and the energy storage system supplies power to the load, the required discharging power corresponds to the load's power consumption demand.

[0042] In some embodiments, the operating condition data also includes dynamic performance data of the energy storage unit.

[0043] Dynamic performance data refers to a set of parameters used to describe the real-time status and performance of the energy storage unit. It can include data directly collected by the data acquisition module or data calculated based on the collected data.

[0044] In this embodiment, dynamic performance data may include data such as state of charge (SOC), real-time charge / discharge power, charge / discharge ramp rate, and state of health (SOH).

[0045] Step 120: If the operating condition data meets the preset operating conditions, obtain the first dispatchable power of the first energy storage unit 710.

[0046] In this embodiment, real-time operating condition data of the energy storage system is obtained. If the operating condition data meets the preset operating condition conditions, it is determined that the current operating condition of the energy storage system belongs to the preset operating condition type. For the preset operating condition type, the first energy storage unit 710 is called first to meet the power requirements of the energy storage system.

[0047] The preset operating conditions include at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; the required power is greater than or equal to a preset power threshold.

[0048] In this embodiment, when the battery body temperature is less than or equal to a preset temperature threshold, the energy storage system operates in a low-temperature condition, which is a preset operating condition type. At this time, the first energy storage unit 710 is preferentially called, which can make full use of the high capacity retention rate and high charge and discharge efficiency of the sodium battery in the first energy storage unit 710 in the low-temperature environment (the sodium battery capacity retention rate is ≥80% at -20℃), thereby improving the performance of the energy storage system.

[0049] In actual operation, the preset temperature threshold can be from -5℃ to -15℃. For example, if the preset temperature threshold is -10℃, when the battery body temperature is less than or equal to -10℃, it is determined that the operating condition data meets the preset operating condition conditions, and the current operating condition of the energy storage system belongs to the preset low temperature operating condition type.

[0050] In this embodiment, when the required power is greater than or equal to a preset power threshold, the energy storage system operates in a high-power condition, which is a preset operating condition type. At this time, the first energy storage unit 710 is called first, which can make full use of the high peak power density of the sodium battery in the first energy storage unit 710 and the excellent thermal stability of the sodium battery during high-power charging and discharging, thereby improving the performance of the energy storage system.

[0051] In practice, the preset power threshold can be set according to the rated power of the energy storage system.

[0052] For example, the rated power of the energy storage system is P sys The preset power threshold can be 75%P sys -85%P sys The preset power threshold is set to 80%P. sys When the required power is greater than or equal to 80% P sys The system determines that the operating condition data meets the preset operating conditions, and the current operating condition of the energy storage system belongs to the preset high-power operating condition type.

[0053] The first dispatchable power refers to the actual power limit that the first energy storage unit 710 can provide or accept, which can be divided into the maximum acceptable power in the charging mode (i.e., the upper limit of dispatchable charging power) and the maximum power that can be provided in the discharging mode (i.e., the limit of dispatchable discharging power).

[0054] In actual implementation, the first dispatchable power is determined based on the current state of charge, health status, ramp rate of the first energy storage unit 710, and the rated maximum power that the first energy storage unit 710 can provide.

[0055] In this embodiment, when the operating condition data meets the preset operating conditions, the first dispatchable power of the first energy storage unit 710 is obtained, and it is determined whether the power that the first energy storage unit 710 can actually provide or receive can meet the current power demand.

[0056] For example, in discharge mode, the maximum power that the first energy storage unit 710 can provide is compared with the required discharge power to determine whether the power that the first energy storage unit 710 can actually provide can meet the power demand of the load.

[0057] For example, in charging mode, the maximum acceptable power of the first energy storage unit 710 is compared with the charging demand power or the power that an external power source can provide (such as photovoltaic power, grid power, etc.) to determine whether the actual acceptable power of the first energy storage unit 710 can fully absorb the external power. Step 130: When the first dispatchable power is greater than or equal to the demand power, the first energy storage unit 710 is controlled to operate with the demand power as the power reference value.

[0058] In this embodiment, if the first dispatchable power is greater than or equal to the required power, it indicates that the first energy storage unit 710 can meet the power requirements of the energy storage system under the current operating conditions, and the first energy storage unit 710 is controlled to operate with the required power as the power reference value.

[0059] In related technologies, hybrid energy storage battery systems mostly adopt control logic that allocates power in a fixed ratio. The power allocation strategy lacks flexibility and cannot be dynamically adjusted according to the real-time operating status, resulting in a shortened battery life. The priority settings under different operating conditions are unreasonable, and the advantages of different types of batteries are not fully utilized.

[0060] In this embodiment, the operating condition data of the energy storage system is acquired in real time, and it is determined whether the operating condition data meets the preset operating condition conditions, that is, whether the current operating condition of the energy storage system belongs to the preset operating condition type. When the battery body temperature is less than or equal to the preset temperature threshold, the energy storage system operates in the preset low temperature condition. When the demand power is greater than or equal to the preset power threshold, the energy storage system operates in the preset high power condition. Under low temperature and high power conditions, the first energy storage unit 710, including the sodium battery, is preferentially called. This fully utilizes the low temperature performance advantage and high power tolerance advantage of the sodium battery, and can also avoid excessive loss of a single type of energy storage unit, extend the battery life, and significantly improve the overall performance of the energy storage system.

[0061] According to the control method of the energy storage system provided in the embodiments of this application, by acquiring the operating condition data of the energy storage system in real time, it is determined whether the operating condition data meets the preset operating condition conditions. When it is determined that the energy storage system is in the preset low temperature condition or high power condition, the first energy storage unit 710, including the sodium battery, is preferentially called to provide the power required by the load or to receive charging power. If the first schedulable power is greater than or equal to the required power, the first energy storage unit 710 is controlled to operate with the required power as the power reference value. The output or charging of the energy storage unit can be adjusted according to the actual operating conditions, which helps to extend the battery life and significantly improve the overall performance of the energy storage system.

[0062] In some embodiments, after obtaining the first dispatchable power of the first energy storage unit 710, the control method of the energy storage system may further include: when the first dispatchable power is less than the required power, controlling the first energy storage unit 710 to operate with the first dispatchable power as the power reference value, and obtaining the difference power and the second dispatchable power of the second energy storage unit 720; when the second dispatchable power is greater than or equal to the difference power, controlling the second energy storage unit 720 to operate with the difference power as the power reference value.

[0063] The differential power is determined based on the demand power and the first dispatchable power.

[0064] In practice, the differential power can be equal to the difference between the required power and the first dispatchable power.

[0065] In this embodiment, if the first dispatchable power is less than the required power, it indicates that the first energy storage unit 710 cannot meet the power requirements of the energy storage system under the current operating conditions. The first energy storage unit 710 is controlled to operate with the first dispatchable power as the power reference value, and at the same time, the second energy storage unit 720, which includes a lithium battery, is called to bear the difference in power.

[0066] It is understandable that the second dispatchable power refers to the actual power limit that the second energy storage unit 720 can provide or accept, which can be divided into the maximum acceptable power in charging mode (i.e., the upper limit of dispatchable charging power) and the maximum power that can be provided in discharging mode (i.e., the limit of dispatchable discharging power).

[0067] In actual implementation, the second dispatchable power is determined based on the current state of charge, health status, charge / discharge ramp rate of the second energy storage unit 720, and the rated maximum power that the second energy storage unit 720 can provide or the maximum acceptable power.

[0068] In this embodiment, when the second dispatchable power is greater than or equal to the differential power, it indicates that the second energy storage unit 720 can fully bear the differential power, and the first energy storage unit 710 and the second energy storage unit 720 can meet the power demand of the energy storage system under the current operating conditions.

[0069] For example, in discharge mode, the power demand of the load is P. load The first dispatchable power of the first energy storage unit 710 is P. Na-available .

[0070] If P Na-available ≥P load The first energy storage unit 710 alone undertakes the power demand of the load.

[0071] If P Na-available <P load The first energy storage unit 710 uses PNa-available Output power, the calculated differential power is P compensate =P load -P Na-available The second dispatchable power of the second energy storage unit 720 is P. Li-available .

[0072] If P compensate ≤P Li-available The second energy storage unit 720 uses P compensate The output power is supplemented by the second energy storage unit 720, with sodium-lithium batteries providing power in conjunction.

[0073] The power provided by the second energy storage unit 720 shall not exceed the second dispatchable power.

[0074] For example, in charging mode, the charging power provided by the external power source to the energy storage system is P. charge The first dispatchable power of the first energy storage unit 710 is P. Na-charge-available .

[0075] If P Na-charge-available ≥P charge The first energy storage unit 710 alone undertakes the charging power of the system.

[0076] If P Na-charge-available <P charge The first energy storage unit 710 uses P Na-charge-available The received power was calculated, and the differential power was P. supplement =P charge -P Na-charge-available The second dispatchable power of the second energy storage unit 720 is P. Li-charge-available .

[0077] If P supplement ≤P Li-charge-available The second energy storage unit 720 uses P supplement The system accepts the remaining differential power, wherein the power accepted by the second energy storage unit 720 does not exceed the second dispatchable power. It should be noted that when the second dispatchable power is less than the differential power, it indicates that the second energy storage unit 720 cannot fully bear the differential power. The first energy storage unit 710 and the second energy storage unit 720 cannot meet the power demand of the energy storage system under the current operating conditions. The energy storage system can output a first indication message to instruct a reduction in the required power, thus preventing overcharging and over-discharging of the energy storage system.

[0078] In actual operation, the second energy storage unit 720 must meet the operating constraints of the lithium battery. The real-time charging and discharging power shall not exceed the maximum charging and discharging power of the second energy storage unit 720, and the lithium battery temperature shall not exceed the preset threshold (such as 55°C) during the charging and discharging mode. If it exceeds the threshold, the temperature control protection mechanism shall be activated to reduce the output power of the lithium battery.

[0079] In some embodiments, after acquiring the operating condition data of the energy storage system, the control method of the energy storage system may further include: if the operating condition data does not meet the preset operating conditions, determining a first power allocation coefficient for each energy storage unit based on the operating condition data; determining a power reference value for each energy storage unit based on the demand power and the first power allocation coefficient, and controlling the energy storage unit to operate according to the corresponding power reference value.

[0080] In this embodiment, if the operating condition data of the energy storage system does not meet the preset operating conditions, that is, the current operating condition of the energy storage system is not a low temperature condition or a high power condition, the first power allocation coefficient of each energy storage unit in the energy storage system can be determined based on the current operating condition data of the energy storage system. The energy storage system implements real-time dynamic power allocation to match the current operating condition of the system and improve the system's operating efficiency and stability.

[0081] In practice, based on the current operating data of the energy storage system, the corresponding first power allocation coefficient is determined with optimization goals such as balancing lifespan loss, reducing dispatch frequency, and improving operational economy.

[0082] In some embodiments, the operating condition data includes health status data and state of charge data; determining the first power allocation coefficient of each energy storage unit based on the operating condition data includes: determining the first power allocation coefficient of each energy storage unit based on the health status data and state of charge data of the first energy storage unit 710 and the health status data and state of charge data of the second energy storage unit 720.

[0083] In this embodiment, based on the health status data and state of charge data of the first energy storage unit 710 and the second energy storage unit 720, the first power allocation coefficient of each energy storage unit in the energy storage system is calculated. The energy storage units with higher state of charge and better health status are preferentially called to balance the life loss of different energy storage units so as to minimize the life loss of the energy storage system.

[0084] In practice, the current absolute remaining capacity of an energy storage unit can be calculated based on its State of Health (SOH) and State of Charge (SOC) data. The unit's ability to provide or accept power can be assessed, and a first power allocation factor can be determined based on this ability to allocate power to the energy storage unit that is appropriate for its current state.

[0085] For example, (SOH) Li ×SOC Li ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is used as the first power allocation coefficient of the second energy storage unit 720, and 1-(SOH) is used as the first power allocation coefficient. Li ×SOC Li ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is used as the first power distribution coefficient of the first energy storage unit 710.

[0086] For example, (SOH) Na ×SOC Na ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is used as the first power allocation coefficient of the first energy storage unit 710, and 1-(SOH) is used as the first power allocation coefficient. Na ×SOC Na ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) serves as the first power allocation factor for the second energy storage unit 720.

[0087] Among them, SOH Na For the first energy storage unit 710, the state of health, SOC Na For the first energy storage unit 710, the state of charge (SOH) is... Li For the second energy storage unit 720, the SOC Li This represents the state of charge of the second energy storage unit 720.

[0088] In this embodiment, the power reference value corresponding to each energy storage unit is determined according to the first power allocation coefficient of each energy storage unit, and the energy storage unit is controlled to operate according to the corresponding power reference value. This allows batteries with higher SOC and better SOH to bear more power, coordinates the output of different types of battery clusters, and reduces lifespan loss while ensuring reasonable power allocation of the entire energy storage system.

[0089] In actual operation, when the operating condition data of the energy storage system does not meet the preset operating conditions, the current operating condition of the energy storage system can be called the normal operating condition.

[0090] For example, the preset temperature threshold is -10℃, and the preset power threshold is set to 80%P. sys When the battery body temperature is T, the required power is P. load T > -10℃ and P load <80%P sys The energy storage system operates under normal conditions.

[0091] Understandably, based on the total power demand and the first power allocation coefficient of each energy storage unit, the product of the power demand and the first power allocation coefficient can be used as the power reference value of the energy storage unit, and the energy storage unit can be controlled to operate according to the corresponding power reference value.

[0092] For example, in discharge mode, the power reference values ​​of the first energy storage unit 710 and the second energy storage unit 720 can be calculated according to the following formula: P Li-allocate =P load ×(SOH Li ×SOC Li ) / (SOH Li ×SOC Li +SOH Na ×SOC Na )P Na-allocate =P load -P Li-allocate Among them, P load P is the load power required during discharge. Li-allocate P is the power reference value for the second energy storage unit 720. Na-allocate This is the power reference value for the first energy storage unit 710.

[0093] In this embodiment, (SOH) Li ×SOC Li ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is the first power distribution coefficient of the second energy storage unit 720, 1-(SOH) Li ×SOC Li ) / (SOHLi ×SOC Li +SOH Na ×SOC Na ) is the first power distribution coefficient of the first energy storage unit 710.

[0094] For example, in charging mode, P Na-allocate =P charge ×(SOH Na ×SOC Na ) / (SOH Li ×SOC Li +SOH Na ×SOC Na )P Li-allocate =P charge -P Na-allocate Among them, P charge P is the charging power required for the energy storage system. Na-allocate P is the power reference value for the first energy storage unit 710. Li-allocate This is the power reference value for the second energy storage unit 720.

[0095] In this embodiment, (SOH) Na ×SOC Na ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is the first power distribution coefficient of the first energy storage unit 710, 1-(SOH) Na ×SOC Na ) / (SOH Li ×SOC Li +SOH Na ×SOC Na ) is the first power distribution coefficient of the second energy storage unit 720.

[0096] In this embodiment, the formula enables energy storage units with higher state of charge and better health to bear or receive more power, thereby balancing the lifespan loss of different energy storage units and avoiding excessive loss of a single energy storage unit.

[0097] In some embodiments, the control method for the energy storage system may further include: controlling a faulty energy storage unit to disconnect from the energy storage system and outputting fault alarm information.

[0098] In this embodiment, when a certain energy storage unit fails, the faulty energy storage unit can be quickly switched off to improve the stability of system operation. At the same time, a fault alarm message is output to remind the user that the energy storage unit needs to be repaired or replaced.

[0099] In actual operation, the types of faults in energy storage units include, but are not limited to, overvoltage faults, undervoltage faults, overcurrent faults, overtemperature faults, and insulation faults.

[0100] In this embodiment, by collecting data such as voltage, current, temperature and insulation resistance signals of each energy storage unit in real time, it is possible to determine whether the energy storage unit has failed and the corresponding failure type. When a failure of a certain energy storage unit is detected, the faulty unit can be quickly disconnected, effectively suppressing the expansion of the fault range. The energy storage system has a fast fault response speed, which can effectively shorten the fault handling time. For example, the faulty unit can be disconnected within 10 milliseconds.

[0101] In some embodiments, controlling the faulty energy storage unit to disconnect from the energy storage system may include: controlling the faulty energy storage unit to disconnect from the energy storage system and obtaining the sum of the dispatchable power of the remaining energy storage units in the energy storage system; if the sum of the dispatchable power is greater than or equal to the demand power, determining the power reference value of each remaining energy storage unit in the energy storage system based on the demand power and the second power allocation coefficient, and controlling the remaining energy storage units to operate according to the corresponding power reference value.

[0102] The second power allocation coefficient is determined based on the dispatchable power of the remaining energy storage units.

[0103] In this embodiment, the faulty energy storage unit is switched out, and the dispatchable power of the remaining normal energy storage units is counted. The relationship between the sum of the dispatchable power of the remaining energy storage units in the energy storage system and the required power is determined. If the sum of the dispatchable power is greater than or equal to the required power, it indicates that the remaining normal energy storage units in the energy storage system can meet the current power demand. Based on the required power and the second power allocation coefficient, the power reference value of the remaining normal energy storage units is calculated, and the remaining normal energy storage units are controlled to operate according to the corresponding power reference value.

[0104] The system controls the disconnection of faulty energy storage units from the energy storage system. Simultaneously, based on the required power and the second power allocation coefficient of the remaining energy storage units, it calculates the power reference value of the remaining normal energy storage units, completes the redistribution and issuance of power commands, and controls the remaining normal energy storage units to operate stably according to the corresponding power reference value. This enables fault isolation without shutdown and continuous power output without interruption, significantly improving the overall operational safety and power supply stability of the energy storage system.

[0105] In practice, the second power allocation coefficient can be the ratio of the dispatchable power of the energy storage unit to the sum of the dispatchable power of the energy storage system. The larger the dispatchable power of the energy storage unit, the larger the corresponding second power allocation coefficient. The power reference value calculated based on the demand power and the second power allocation coefficient is also larger, ensuring that the power output (or input) of the remaining normal energy storage units is uniform and avoiding overload of some energy storage units.

[0106] It should be noted that dispatchable power refers to the actual power that the energy storage unit can provide or accept. It is related to the current state of charge, health status, charge / discharge ramp rate, and rated maximum power that the energy storage unit can provide or accept. The first dispatchable power, the second dispatchable power, and the dispatchable power of the remaining normal energy storage units can be obtained using the same calculation method.

[0107] For example, in discharge mode, the sum of the dispatchable power of the remaining energy storage units in the energy storage system is P. total-available The load power requirement is P load .

[0108] In this embodiment, the energy storage system has m remaining first energy storage units 710 and n remaining second energy storage units 720. The formula for calculating the sum of dispatchable power is as follows:

[0109] Where i = 1, 2…m, j = 1, 2…n.

[0110] If P total-available ≥P load The load demand is allocated according to the second power allocation coefficient of each energy storage unit.

[0111] Wherein, the second power allocation coefficient of the i-th first energy storage unit 710 is P Na-i-available / P total-available The power reference value of the i-th first energy storage unit 710 is (P Na-i-available / P total-available )*P load .

[0112] The second power allocation coefficient of the j-th second energy storage unit 720 is P. Li-j-available / P total-available The power reference value of the j-th second energy storage unit 720 is (P Li-j-available / P total-available )*P load .

[0113] If P total-available <P load Initiate a load power limiting strategy, identify critical and non-critical loads, ensure the power supply needs of critical loads are met, and proportionally reduce the power of non-critical loads, ensuring that the total load power after reduction does not exceed P. total-available .

[0114] For example, in charging mode, the sum of the dispatchable power of the remaining energy storage units in the energy storage system is P. total-charge-available The charging power requirement is P. charge .

[0115] In this embodiment, the energy storage system has m remaining first energy storage units 710 and n remaining second energy storage units 720. The formula for calculating the sum of dispatchable power is as follows:

[0116] Where i = 1, 2…m, j = 1, 2…n.

[0117] If P total-charge-available ≥P charge The load demand is allocated according to the second power allocation coefficient of each energy storage unit.

[0118] Wherein, the second power allocation coefficient of the i-th first energy storage unit 710 is P Na-i-charge-available / P total-charge-available The power reference value of the i-th first energy storage unit 710 is (P Na-i-charge-available / P total-charge-available )*P charge .

[0119] The second power allocation coefficient of the j-th second energy storage unit 720 is P. Li-j-charge-available / P total-charge-available The power reference value of the j-th second energy storage unit 720 is (P Li-j-charge-available / P total-charge-available )*P charge .

[0120] If P total-charge-available <P charge Energy storage system according to P total-charge-available Charging is performed, and excess charging power is discharged. The calculation method for dispatchable power is explained in detail below.

[0121] In some embodiments, the dispatchable power of the energy storage unit is determined by the following steps: determining a first correction factor based on the state of charge of the energy storage unit; determining a second correction factor based on the health status of the energy storage unit; determining a third correction factor based on the ramp rate of the energy storage unit; and determining the dispatchable power of the energy storage unit based on the maximum charge / discharge power of the energy storage unit, the first correction factor, the second correction factor, and the third correction factor.

[0122] It is understandable that the maximum charging and discharging power of an energy storage unit includes the maximum charging power and the maximum discharging power. The maximum discharging power is the upper limit of the power that the energy storage unit can actually provide, and the maximum charging power is the upper limit of the power that the energy storage unit can actually accept.

[0123] In this embodiment, the schedulable power can be the product of the maximum charge / discharge power, the first correction factor, the second correction factor, and the third correction factor. At the same time, the schedulable power will not exceed the maximum charge / discharge power to avoid overcharging and over-discharging of the energy storage unit.

[0124] In practice, the formula for calculating dispatchable power is as follows: P available =min(P max ×k SOC ×k SOH ×k R P max Among them, P available For dispatchable power, P max For the maximum charge / discharge power, k SOC k is the first correction factor. SOH k is the second correction factor. R is the third correction coefficient, and min() is the function to find the minimum value.

[0125] Understandably, in charging mode, the dispatchable power is the actual available or acceptable charging and discharging power, and the maximum charging and discharging power is the maximum charging power of the energy storage unit; in discharging mode, the dispatchable power is the actual available discharging power, and the maximum charging and discharging power is the maximum charging and discharging power of the energy storage unit.

[0126] In some embodiments, determining a first correction coefficient based on the state of charge of the energy storage unit may include: when the state of charge of the energy storage unit is within a target charge range, the first correction coefficient is set to a first preset value; or, when the state of charge of the energy storage unit is not within the target charge range, the first correction coefficient is determined based on a first mapping relationship between the state of charge and the first correction coefficient, wherein the first correction coefficient is less than the first preset value, and the first mapping relationship includes at least one linear function relationship.

[0127] The target charge range is a range set according to the current charging and discharging operating mode of the energy storage battery.

[0128] In discharge mode, the target charge range can be 80%-100%. When the charge state of the energy storage unit is within the target charge range, the energy storage unit can release more electrical energy. The first correction coefficient can be a larger fixed value, i.e., the first preset value.

[0129] In actual implementation, the first preset value can be 1 or a value close to 1.

[0130] When the state of charge of the energy storage unit is not within the target state of charge range, that is, when the current state of charge of the energy storage unit is less than 80%, the first correction coefficient is linearly adjusted according to the state of charge of the energy storage unit. The state of charge of the energy storage unit can be substituted into the first mapping relationship to solve for the first correction coefficient corresponding to the current state of charge. At this time, the first correction coefficient is less than the first preset value to limit the discharge capacity of the energy storage unit and avoid over-discharge.

[0131] It should be noted that the first mapping relationship includes one or more linear function relationships. When the state of charge is in different numerical ranges, the first correction coefficient can be solved according to different linear functions.

[0132] Take the first energy storage unit 710, which includes a sodium battery, as an example.

[0133] In discharge mode, the first energy storage unit 710 is in a state of charge (SOC). Na When SOC Na When ≥80%, the first correction factor k SOC =1.0.

[0134] When 50%≤SOC Na When <80%, k is solved using the linear function f(a). SOC k SOC Linear adjustment between 0.8 and 1.0, i.e., k SOC The value range is 0.8-1.0.

[0135] When SOC Na When <50%, k is solved using the linear function f(b). SOC k SOC Linear adjustment within the range of 0.5-0.8, i.e., k SOC The value range is 0.5-0.8.

[0136] In charging mode, the target charge range can be 0% to 20%. When the charge state of the energy storage unit is within the target charge range, the energy storage unit can receive more electrical energy. The first correction coefficient can be a large fixed value, i.e., the first preset value.

[0137] In actual implementation, the first preset value can be 1 or a value close to 1.

[0138] When the state of charge of the energy storage unit is not within the target state of charge range, that is, when the current state of charge of the energy storage unit is greater than 20%, the first correction coefficient is linearly adjusted according to the state of charge of the energy storage unit. The state of charge of the energy storage unit can be substituted into the first mapping relationship to solve for the first correction coefficient corresponding to the current state of charge. At this time, the first correction coefficient is less than the first preset value to limit the charging capacity of the energy storage unit and avoid overcharging.

[0139] Take the first energy storage unit 710, which includes a sodium battery, as an example.

[0140] In charging mode, the first energy storage unit 710 is in a state of charge (SOC). Na When SOC Na When ≤20%, the first correction factor k SOC =1.0.

[0141] When 20% < SOCNa When <50%, k is solved using the linear function f(c). SOC k SOC Linear adjustment between 0.8 and 1.0, i.e., k SOC The value range is 0.8-1.0.

[0142] When SOC Na When ≥50%, k is solved using the linear function f(d). SOC k SOC Linear adjustment within the range of 0.5-0.8, i.e., k SOC The value range is 0.5-0.8.

[0143] In some embodiments, determining a second correction coefficient based on the health status of the energy storage unit may include: when the health status of the energy storage unit is greater than or equal to a second state threshold, the second correction coefficient is set to a second preset value; or, when the health status of the energy storage unit is less than the second state threshold, the second correction coefficient is determined based on a second mapping relationship between the health status and the second correction coefficient, wherein the second correction coefficient is less than the second preset value, and the second mapping relationship includes at least one linear function relationship.

[0144] The second state threshold is a preset health state threshold.

[0145] It is understandable that when the health status of an energy storage unit is less than the second state threshold, it indicates that the available capacity of the energy storage unit is decreasing and the internal resistance is increasing.

[0146] In practice, the second state threshold can be 90%.

[0147] In this embodiment, when the health status of the energy storage unit is greater than or equal to the second state threshold, the second correction coefficient can take a larger fixed value, namely the second preset value.

[0148] In actual implementation, the second preset value can be 1 or a value close to 1.

[0149] When the health status of the energy storage unit is less than the second state threshold, the second correction coefficient is linearly adjusted according to the health status of the energy storage unit. The health status of the energy storage unit can be substituted into the second mapping relationship to solve for the second correction coefficient corresponding to the current health status. At this time, the second correction coefficient is less than the second preset value to limit the charging and discharging capability of the energy storage unit, avoid high rate or high current charging and discharging, reduce cell stress, slow down battery aging, and reduce the risk of thermal runaway.

[0150] It should be noted that the second mapping relationship includes one or more linear function relationships. When the health status is in different numerical ranges, the second correction coefficient can be solved according to different linear functions.

[0151] Take the first energy storage unit 710, which includes a sodium battery, as an example.

[0152] In charging mode, the health status of the first energy storage unit 710 is SOH. Na When SOH Na When ≥90%, the second correction factor k SOH =1.0.

[0153] When 70%≤SOH Na When <90%, k is solved using the linear function f(e). SOH k SOH Linear adjustment between 0.7 and 1.0, i.e., k SOH The value range is 0.7-1.0.

[0154] When SOH Na When <70%, k is solved using the linear function f(g). SOH k SOH Linear adjustment within the range of 0.3-0.7, i.e., k SOH The value range is 0.3-0.7.

[0155] In practice, the health status of an energy storage unit can be calculated using the capacity decay rate and the internal resistance growth rate.

[0156] For example, the formula for calculating the state of health (SOH) of an energy storage unit is as follows: SOH = α × (C current / C rated )+β×(R rated / R current Where α and β are weighting coefficients, α + β = 1, C current C represents the current capacity of the energy storage unit. rated R is the rated capacity of the energy storage unit. current R is the current internal resistance of the energy storage unit. rated This is the rated internal resistance of the energy storage unit.

[0157] In some embodiments, determining a third correction coefficient based on the ramp rate of the energy storage unit includes: when the ramp rate of the energy storage unit is less than or equal to a first rate threshold, the third correction coefficient is set to a third preset value; or, when the ramp rate of the energy storage unit is greater than the first rate threshold, a third correction coefficient is determined based on the first rate threshold and the ramp rate of the energy storage unit, wherein the third correction coefficient is less than the third preset value.

[0158] The ramp rate of an energy storage unit refers to its ability to adjust its output (or input) power per unit time, expressed as the rate of power change.

[0159] In this embodiment, the first rate threshold is a preset ramp rate safety limit. When the ramp rate of the energy storage unit is less than or equal to the first rate threshold, it indicates that the energy storage unit is operating normally. When the ramp rate is greater than the first rate threshold, the energy storage unit changes power at a rate exceeding the design safety limit, and the power of the energy storage unit needs to be limited.

[0160] In practice, the first rate threshold can be the upper limit of the ramp rate of the energy storage unit, that is, the ramp rate under rated operating conditions.

[0161] In this embodiment, when the ramp rate of the energy storage unit is less than or equal to the first rate threshold, the third correction coefficient can take a larger fixed value, namely the third preset value.

[0162] In actual implementation, the third preset value can be 1 or a value close to 1.

[0163] When the ramp rate of the energy storage unit exceeds the first rate threshold, a third correction coefficient is calculated based on the first rate threshold and the ramp rate of the energy storage unit. At this time, the third correction coefficient is less than the third preset value to limit the power change rate of the energy storage unit and ensure system safety.

[0164] In actual implementation, when the ramp rate of the energy storage unit is greater than the first rate threshold, the third correction coefficient can be the ratio of the first rate threshold to the ramp rate of the energy storage unit, and this ratio is less than 1.

[0165] Take the first energy storage unit 710, which includes a sodium battery, as an example.

[0166] The first rate threshold is taken as the upper limit of the ramp rate R of the energy storage unit. Namax When the climbing rate R Na ≤R Namax At that time, the third correction coefficient k R =1.0; when the climbing speed R Na >R Namax At that time, k R =R Namax / R Na .

[0167] In this embodiment, by collecting operating condition data of the energy storage system, the operating condition of the energy storage system is determined, and a dynamic power allocation strategy corresponding to different power levels is constructed. Under low temperature or high power conditions, the first energy storage unit 710, including a sodium battery, is preferentially called to provide power support. When the actual available or acceptable power of the first energy storage unit 710 cannot meet the required power, the second energy storage unit 720, including a lithium battery, makes up the difference in power. At the same time, the energy storage system has an automatic fault unit disconnection function. When a certain energy storage unit fails, the fault unit can be quickly isolated from the system, and the power reference value of each normal unit is adjusted based on the actual available or acceptable power of the remaining normal units. Through the complementary advantages and refined control of lithium batteries and sodium batteries, the operating stability, economy and service life of the hybrid structure energy storage system under different operating conditions are improved, making it suitable for complex application scenarios such as low temperature and high power fluctuation.

[0168] The following is a specific implementation example using an energy storage system to power a load.

[0169] As shown in Figure 2, the energy storage system adopts a string PCS electrical structure, including a lithium battery cluster (i.e., the second energy storage unit 720), a sodium battery cluster (i.e., the first energy storage unit 710), a string PCS module, an operating condition acquisition module, a central control module, a fault detection module, and a monitoring center.

[0170] Among them, the string PCS module adopts a one-PCS configuration in a cluster. The string PCS module is coupled in parallel through the AC-side coupling unit and connected to the load through the AC-side coupling unit to realize the summarization and distribution of AC-side power.

[0171] The operating condition acquisition module is connected to the lithium battery cluster and sodium battery cluster respectively to collect operating condition parameters (i.e., operating condition data); the fault detection module is connected to the lithium battery cluster, sodium battery cluster and string PCS module respectively to monitor fault status; the central control module is connected to the string PCS module, operating condition acquisition module, fault detection module and monitoring center respectively to execute control logic and upload data.

[0172] As shown in Figure 3, after the energy storage system is started, the operating condition acquisition module begins to collect operating condition parameters in real time. The central control module processes the parameters and determines whether they meet the preset operating conditions, i.e., whether they are low temperature or high power conditions, and triggers the corresponding power allocation strategy (low temperature condition, high power condition and normal condition). At the same time, the fault detection module monitors the fault status in real time. If a faulty energy storage unit is detected, the faulty unit is switched out and the remaining cluster power is adjusted.

[0173] In this embodiment, the operating condition acquisition module can collect ambient temperature, battery body temperature T, and load power demand P in real time according to a preset sampling frequency. loadOperating parameters such as lithium battery cluster parameters and sodium battery cluster parameters.

[0174] The ambient temperature can be collected from outside the cabinet of the energy storage system, while the battery body temperature can be collected from the positive, negative and middle positions of the battery cluster. The average of the three measurements is taken as the battery body temperature of the battery cluster.

[0175] Load demand power P load It can be collected through the power sensor on the AC side.

[0176] Lithium-ion battery cluster parameters include the real-time state of charge (SOC) of the lithium-ion battery cluster. Li Charging and discharging power P Li Climbing speed R Li Health status SOH Li Parameters such as the real-time state of charge (SOC) of the sodium battery cluster are included. Na Charging and discharging power P Na Climbing speed R Na Health status SOH Na Parameters such as these.

[0177] Among them, the real-time state of charge can be calculated by combining the ampere-hour integral method with the Kalman filter algorithm, the ramp rate is the rate of change of power per unit time, and the health state can be calculated by the capacity decay rate and the internal resistance growth rate.

[0178] For example, the formula for calculating the state of health (SOH) of an energy storage unit is as follows: SOH = α × (C current / C rated )+β×(R rated / R current Where α and β are weighting coefficients, α + β = 1, C current C represents the current capacity of the energy storage unit. rated R is the rated capacity of the energy storage unit. current R is the current internal resistance of the energy storage unit. rated This is the rated internal resistance of the energy storage unit.

[0179] For lithium battery clusters, α=0.6, β=0.4; for sodium battery clusters, α=0.5, β=0.5.

[0180] The operating condition acquisition module transmits the acquired parameters to the central control module via Ethernet. The central control module filters and reduces noise in the parameters to eliminate abnormal data.

[0181] The central control module determines the current operating condition of the system based on the processed operating parameters and determines the priority call conditions for sodium battery clusters.

[0182] When the battery body temperature T≤-10℃, it is determined to be a low-temperature operating condition. At this time, the sodium battery cluster is used first to make full use of the high capacity retention rate and high charge and discharge efficiency of the sodium battery in the low-temperature environment.

[0183] When the load demand power P load ≥80%P sys (P) sys When the rated power of the energy storage system is reached, it is determined to be a high-power operating condition. At this time, the sodium battery cluster is prioritized to make full use of the high peak power density of the sodium battery and the thermal stability of the sodium battery during high-power charging and discharging.

[0184] When T > -10℃ and P load <80%P sys If the condition is determined to be normal operating condition, the power is dynamically allocated based on the SOC and SOH values ​​of the lithium battery cluster and sodium battery cluster. The battery cluster with higher SOC and SOH values ​​is prioritized to balance the life loss of the two types of batteries.

[0185] As shown in Figure 4, when the energy storage system is determined to be in a low-temperature or high-power condition, the sodium battery priority mode is activated. Based on the number of clusters and the rated operating conditions of individual cells, the maximum output power P of the sodium battery cluster is calculated. Na-max (i.e., maximum discharge power), such as a battery cluster consisting of 100 sodium battery cells with a rated power of 200W, P Na-max =20kW.

[0186] According to P Na-max Calculate the actual power P that a sodium battery cluster can provide. Na-available (Power can be scheduled).

[0187] P Na-available =min(P Na-max ×k Na-SOC ×k Na-SOH ×k Na-R P Na-max Where, k Na-SOC k is the first correction factor for sodium battery clusters. Na-SOH k is the second correction factor for sodium battery clusters. Na-R is the third correction coefficient for the sodium battery cluster, and min() is the minimum value function.

[0188] If P Na-available ≥P load The sodium battery cluster alone handles the load power demand. The central control module sends power control commands to the corresponding PCS module of the sodium battery cluster, controlling the sodium battery cluster to operate at P... load It provides power output while keeping the lithium battery cluster in standby mode to maintain the lowest possible monitoring power consumption.

[0189] If P Na-available <Pload Then calculate the actual power P that the lithium battery cluster can provide. Li-available and differential power P compensate P Li-available The calculation method and P Na-available Similarly, the definitions of each correction coefficient are consistent with those of the sodium battery cluster, only the parameter thresholds are adjusted according to the characteristics of lithium batteries (such as the maximum ramp rate R of lithium batteries). Li-max =3kW / s); P compensate =P load -P Na-available .

[0190] If P compensate ≤P Li-available If the lithium battery clusters compensate for the power difference, the central control module sends a command to the PCS module corresponding to the lithium battery clusters to control its output of the power difference P. compensate Sodium-lithium batteries provide power in conjunction; if P compensate >P Li-available If this occurs, a load power limiting strategy will be activated, prioritizing the power supply needs of critical loads while reducing the power of non-critical loads proportionally (P). compensate -P Li-available ) / P load ×100%.

[0191] When the energy storage system is determined to be under normal operating conditions, the power allocation strategy aims to balance the lifespan loss of lithium-sodium batteries, and the power P allocated to the lithium battery cluster is... Li-allocate =P load ×(SOH Li ×SOC Li ) / (SOH Li ×SOC Li +SOH Na ×SOC Na Sodium battery cluster power distribution P Na-allocate =P load -P Li-allocate This allows battery clusters with higher SOC and better SOH to handle more power, avoiding excessive power loss in a single battery cluster.

[0192] As shown in Figure 5, the fault detection module monitors the operating parameters of each battery cluster in real time, including but not limited to the total voltage of the battery cluster, the voltage of each individual cell, the total current, the battery temperature, and the insulation resistance, to determine whether a fault exists.

[0193] For example, when the total voltage of the battery cluster is ≥1.1 times the rated voltage, or the voltage of a single cell is ≥1.2 times the rated voltage of the single cell, it is determined to be an overvoltage fault; when the total voltage of the battery cluster is ≤0.9 times the rated voltage, or the voltage of a single cell is ≤0.8 times the rated voltage of the single cell, it is determined to be an undervoltage fault; when the charging and discharging current of the battery cluster is ≥1.5 times the rated current, it is determined to be an overcurrent fault; when the battery body temperature is ≥60℃ (lithium battery cluster), or ≥70℃ (sodium battery cluster), it is determined to be an overtemperature fault; when the insulation resistance between the positive and negative terminals of the battery cluster and the casing is ≤1 megohm, it is determined to be an insulation fault.

[0194] If no fault exists, monitoring continues. If a fault exists, the faulty cluster is located, and a fault signal is sent to the central control module. The central control module performs a faulty cluster switch-out operation, activates an alarm, and uploads fault information. Then, the number of remaining normal clusters is counted, the total remaining schedulable power is calculated, and the power output is adjusted according to the relationship between the total remaining schedulable power and the load demand.

[0195] After receiving a fault signal, the central control module executes the following fault handling process: Fault location: Based on the cluster number in the fault signal, determine the faulty battery cluster; Fault cut-off: The central control module sends a cut-off command to the PCS module corresponding to the faulty cluster. The relay inside the PCS module disconnects within 10 milliseconds, isolating the faulty cluster from the system AC side to prevent the fault from spreading to other normal clusters; Fault alarm: The central control module activates the audible and visual alarm device and uploads the fault information (including the faulty cluster number, fault type, and fault occurrence time) to the monitoring center for timely handling by maintenance personnel.

[0196] After a faulty battery cluster is switched off, the central control module counts the number of remaining normal lithium-ion battery clusters and normal sodium-ion battery clusters. Combining this with the real-time SOC, SOH, and ramp rate of each normal cluster, it recalculates the total remaining dispatchable power of the energy storage system, i.e., the sum of the dispatchable power P of the energy storage system. total-available .

[0197] According to P total-available With P load Different power adjustment strategies are adopted based on the magnitude of the relationship.

[0198] If P total-available ≥P load The load demand is allocated according to the initial power ratio of each normal cluster, where the initial power ratio is P of each normal cluster. Na-available (or P) Li-available ) and P total-available The ratio ensures that the power output of each normal cluster is uniform, avoiding overloading of some clusters.

[0199] If P total-available <P loadInitiate a load power limiting strategy, first identifying critical and non-critical loads (predefined through a load priority configuration table), ensuring the power supply needs of critical loads (critical load power supply priority ≥ 90%), and proportionally reducing the power of non-critical loads, with the total load power after reduction not exceeding P. total-available .

[0200] Meanwhile, the central control module monitors the operating status of the remaining normal clusters in real time. If the power shortage worsens, it issues a shutdown warning signal to remind maintenance personnel to take emergency measures.

[0201] Understandably, when the energy storage system is in charging mode, the control strategy is similar to that in discharging mode. Under low temperature or high power charging conditions, sodium battery clusters take the lead in bearing the charging power. If the sodium battery clusters are fully charged or cannot bear all the charging power, the lithium battery clusters will bear the remaining charging power.

[0202] In this embodiment, a dynamic power allocation optimization model is constructed by combining multiple operating condition parameters such as temperature, charge / discharge power, ramp rate, and remaining lifespan. This model clarifies the priority deployment strategy for sodium batteries under low-temperature and high-power conditions, fully leveraging the low-temperature performance and high-power tolerance advantages of sodium batteries while avoiding excessive wear on individual battery clusters and extending battery lifespan. Furthermore, an automatic fault cluster switching mechanism is adopted, which can isolate faulty clusters from the system in a short time, preventing fault propagation. A remaining cluster power adjustment strategy is also designed to precisely adjust power output based on the status of remaining normal clusters, ensuring system operational stability. Even further, a string-type PCS electrical structure is adopted, and the one-cluster-one-management configuration avoids the single-point failure risk of centralized PCS, while the AC-side coupling method improves the system's expansion flexibility. Finally, by leveraging the complementary advantages of lithium batteries and sodium batteries, the system's dependence on high-cost lithium batteries is reduced, while extending battery lifespan and system operating cycle, thus lowering maintenance costs.

[0203] The energy storage system control method provided in this application can be executed by an energy storage system control device. This application uses the example of an energy storage system control device executing the energy storage system control method to illustrate the energy storage system control device provided in this application.

[0204] This application also provides a control device for an energy storage system. The energy storage system includes at least two energy storage units connected in parallel. The at least two energy storage units are a first energy storage unit 710 including a sodium battery and a second energy storage unit 720 including a lithium battery.

[0205] As shown in Figure 6, the control device of the energy storage system includes: an acquisition module 610 for acquiring operating condition data of the energy storage system; a first processing module 620 for acquiring the first dispatchable power of the first energy storage unit 710 when the operating condition data meets preset operating conditions; and a second processing module 630 for controlling the first energy storage unit 710 to operate with the demand power as the power reference value when the first dispatchable power is greater than or equal to the demand power.

[0206] The preset operating conditions include at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; the required power is greater than or equal to a preset power threshold.

[0207] According to the control device of the energy storage system provided in the embodiments of this application, by acquiring the operating condition data of the energy storage system in real time, it determines whether the operating condition data meets the preset operating conditions. When it is determined that the energy storage system is in the preset low temperature condition or high power condition, the first energy storage unit 710 including the sodium battery is preferentially called to provide the power required by the load or to receive charging power. If the first dispatchable power is greater than or equal to the required power, the first energy storage unit 710 is controlled to operate with the required power as the power reference value. The output or charging of the energy storage unit can be adjusted according to the actual operating conditions, which helps to extend the battery life and significantly improve the overall performance of the energy storage system.

[0208] In some embodiments, after acquiring the first dispatchable power of the first energy storage unit 710, the second processing module 630 is further configured to, when the first dispatchable power is less than the required power, control the first energy storage unit 710 to operate with the first dispatchable power as the power reference value, and acquire the difference power and the second dispatchable power of the second energy storage unit 720, wherein the difference power is determined based on the required power and the first dispatchable power; and when the second dispatchable power is greater than or equal to the difference power, control the second energy storage unit 720 to operate with the difference power as the power reference value.

[0209] In some embodiments, after acquiring the operating condition data of the energy storage system, the first processing module 620 is further configured to determine the first power allocation coefficient of each energy storage unit based on the operating condition data if the operating condition data does not meet the preset operating condition conditions; the second processing module 630 is further configured to determine the power reference value of each energy storage unit based on the demand power and the first power allocation coefficient, and control the energy storage unit to operate according to the corresponding power reference value.

[0210] In some embodiments, the operating condition data includes health status data and state of charge data; the first processing module 620 is used to determine the first power allocation coefficient of each energy storage unit based on the operating condition data, including: determining the first power allocation coefficient of each energy storage unit based on the health status data and state of charge data of the first energy storage unit 710, and the health status data and state of charge data of the second energy storage unit 720.

[0211] In some embodiments, the second processing module 630 is further configured to control the faulty energy storage unit to disconnect from the energy storage system and output fault alarm information.

[0212] In some embodiments, the second processing module 630 is further configured to control the faulty energy storage unit to disconnect from the energy storage system and obtain the sum of the dispatchable power of the remaining energy storage units in the energy storage system; if the sum of dispatchable power is greater than or equal to the demand power, determine the power reference value of each remaining energy storage unit in the energy storage system based on the demand power and the second power allocation coefficient, and control the remaining energy storage units to operate according to the corresponding power reference value; wherein, the second power allocation coefficient is determined based on the dispatchable power of the remaining energy storage units.

[0213] In some embodiments, the first processing module 620 is configured to determine the dispatchable power of the energy storage unit through the following steps: determining a first correction coefficient based on the state of charge of the energy storage unit; determining a second correction coefficient based on the health status of the energy storage unit; determining a third correction coefficient based on the ramp rate of the energy storage unit; and determining the dispatchable power of the energy storage unit based on the maximum charge / discharge power of the energy storage unit, the first correction coefficient, the second correction coefficient, and the third correction coefficient.

[0214] In some embodiments, the first processing module 620 is configured to determine a first correction coefficient based on the state of charge of the energy storage unit, including: when the state of charge of the energy storage unit is within a target charge range, the first correction coefficient is set to a first preset value; or, when the state of charge of the energy storage unit is not within the target charge range, the first correction coefficient is determined based on a first mapping relationship between the state of charge and the first correction coefficient, wherein the first correction coefficient is less than the first preset value, and the first mapping relationship includes at least one linear function relationship.

[0215] In some embodiments, the first processing module 620 is configured to determine a second correction coefficient based on the health status of the energy storage unit, including: when the health status of the energy storage unit is greater than or equal to a second state threshold, the second correction coefficient is set to a second preset value; or, when the health status of the energy storage unit is less than the second state threshold, the second correction coefficient is determined based on a second mapping relationship between the health status and the second correction coefficient, wherein the second correction coefficient is less than the second preset value, and the second mapping relationship includes at least one linear function relationship.

[0216] In some embodiments, the first processing module 620 is configured to determine a third correction coefficient based on the ramp rate of the energy storage unit, including: when the ramp rate of the energy storage unit is less than or equal to a first rate threshold, the third correction coefficient is set to a third preset value; or, when the ramp rate of the energy storage unit is greater than the first rate threshold, the third correction coefficient is determined based on the first rate threshold and the ramp rate of the energy storage unit, wherein the third correction coefficient is less than the third preset value.

[0217] The control device for the energy storage system in this application embodiment can be an electronic device or a component in an electronic device, such as an integrated circuit or a chip.

[0218] The control device for the energy storage system provided in this application embodiment can realize the various processes implemented in the above-described energy storage system control method embodiment. To avoid repetition, it will not be described again here.

[0219] As shown in Figure 7, this application embodiment also provides an energy storage system, which includes at least two energy storage units connected in parallel and a controller 730.

[0220] At least two energy storage units are divided into a first energy storage unit 710 including a sodium battery and a second energy storage unit 720 including a lithium battery. Each energy storage unit is connected to an energy storage converter, and the AC sides of at least two energy storage converters are connected in parallel.

[0221] In this embodiment, the first energy storage unit 710 is connected to the first energy storage converter 711, and the second energy storage unit 720 is connected to the second energy storage converter 722.

[0222] The controller 730 is connected to at least two energy storage units and is used to execute the control method of the energy storage system described above.

[0223] According to the energy storage system provided in the embodiments of this application, by acquiring the operating condition data of the energy storage system in real time, it is determined whether the operating condition data meets the preset operating conditions. When it is determined that the energy storage system is in the preset low temperature condition or high power condition, the first energy storage unit 710, including the sodium battery, is preferentially called to provide the power required by the load or to receive charging power. If the first schedulable power is greater than or equal to the required power, the first energy storage unit 710 is controlled to operate with the required power as the power reference value. The output or charging of the energy storage unit can be adjusted according to the actual operating conditions, which helps to extend the battery life and significantly improve the overall performance of the energy storage system.

[0224] In some embodiments, as shown in FIG8, this application embodiment also provides an electronic device 800, including a processor 801, a memory 802, and a computer program stored in the memory 802 and executable on the processor 801. When the program is executed by the processor 801, it implements the various processes of the control method embodiment of the energy storage system described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0225] It should be noted that the electronic devices in the embodiments of this application include the mobile electronic devices and non-mobile electronic devices described above.

[0226] This application also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the control method embodiment of the energy storage system described above and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0227] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0228] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the control method of the energy storage system described above.

[0229] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0230] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described energy storage system control method embodiment and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0231] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0232] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0233] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0234] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0235] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0236] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method for an energy storage system, characterized in that, The energy storage system includes at least two energy storage units connected in parallel. The at least two energy storage units are divided into a first energy storage unit including a sodium battery and a second energy storage unit including a lithium battery. The method includes: acquiring operating condition data of the energy storage system; acquiring a first dispatchable power of the first energy storage unit when the operating condition data meets preset operating conditions; and controlling the first energy storage unit to operate with the required power as a power reference value when the first dispatchable power is greater than or equal to the required power. The operating condition data includes temperature data of the energy storage system and the required power. The temperature data includes the battery body temperature. The preset operating conditions include at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; and the required power is greater than or equal to a preset power threshold.

2. The control method for the energy storage system according to claim 1, characterized in that, After obtaining the first dispatchable power of the first energy storage unit, the method further includes: when the first dispatchable power is less than the required power, controlling the first energy storage unit to operate with the first dispatchable power as a power reference value, and obtaining the difference power and the second dispatchable power of the second energy storage unit, wherein the difference power is determined based on the required power and the first dispatchable power; when the second dispatchable power is greater than or equal to the difference power, controlling the second energy storage unit to operate with the difference power as a power reference value.

3. The control method for the energy storage system according to claim 1, characterized in that, After acquiring the operating condition data of the energy storage system, the method further includes: if the operating condition data does not meet the preset operating condition conditions, determining a first power allocation coefficient for each energy storage unit based on the operating condition data; determining a power reference value for each energy storage unit based on the required power and the first power allocation coefficient, and controlling the energy storage unit to operate according to the corresponding power reference value.

4. The control method for the energy storage system according to claim 3, characterized in that, The operating condition data includes health status data and state of charge data; determining the first power allocation coefficient of each energy storage unit based on the operating condition data includes: determining the first power allocation coefficient of each energy storage unit based on the health status data and state of charge data of the first energy storage unit, and the health status data and state of charge data of the second energy storage unit.

5. The control method for the energy storage system according to claim 1, characterized in that, The method further includes: controlling the faulty energy storage unit to disconnect from the energy storage system and outputting fault alarm information.

6. The control method for the energy storage system according to claim 5, characterized in that, The method of controlling the faulty energy storage unit to disconnect from the energy storage system includes: disconnecting the faulty energy storage unit from the energy storage system and obtaining the sum of the dispatchable power of the remaining energy storage units in the energy storage system; if the sum of the dispatchable power is greater than or equal to the demand power, determining the power reference value of each remaining energy storage unit in the energy storage system based on the demand power and a second power allocation coefficient, and controlling the remaining energy storage units to operate according to the corresponding power reference value; wherein, the second power allocation coefficient is determined based on the dispatchable power of the remaining energy storage units.

7. The control method for the energy storage system according to any one of claims 1-6, characterized in that, The dispatchable power of the energy storage unit is determined by the following steps: determining a first correction factor based on the state of charge of the energy storage unit; determining a second correction factor based on the health status of the energy storage unit; A third correction coefficient is determined based on the ramp rate of the energy storage unit; The dispatchable power of the energy storage unit is determined based on the maximum charge / discharge power of the energy storage unit, the first correction factor, the second correction factor, and the third correction factor.

8. The control method for the energy storage system according to claim 7, characterized in that, The step of determining the first correction coefficient based on the state of charge of the energy storage unit includes: when the state of charge of the energy storage unit is within the target charge range, the first correction coefficient is set to a first preset value; or, when the state of charge of the energy storage unit is not within the target charge range, the first correction coefficient is determined based on a first mapping relationship between the state of charge and the first correction coefficient, wherein the first correction coefficient is less than the first preset value, and the first mapping relationship includes at least one linear function relationship.

9. The control method for the energy storage system according to claim 7, characterized in that, The step of determining the second correction coefficient based on the health status of the energy storage unit includes: when the health status of the energy storage unit is greater than or equal to a second state threshold, the second correction coefficient is set to a second preset value; or, when the health status of the energy storage unit is less than the second state threshold, the second correction coefficient is determined based on a second mapping relationship between the health status and the second correction coefficient, wherein the second correction coefficient is less than the second preset value, and the second mapping relationship includes at least one linear function relationship.

10. The control method for the energy storage system according to claim 7, characterized in that, The step of determining the third correction coefficient based on the ramp rate of the energy storage unit includes: when the ramp rate of the energy storage unit is less than or equal to the first rate threshold, the third correction coefficient is set to a third preset value; or, when the ramp rate of the energy storage unit is greater than the first rate threshold, the third correction coefficient is determined based on the first rate threshold and the ramp rate of the energy storage unit, wherein the third correction coefficient is less than the third preset value.

11. A control device for an energy storage system, characterized in that, The energy storage system includes at least two energy storage units connected in parallel. The at least two energy storage units are divided into a first energy storage unit including a sodium battery and a second energy storage unit including a lithium battery. The device includes: an acquisition module for acquiring operating condition data of the energy storage system; a first processing module for acquiring a first dispatchable power of the first energy storage unit when the operating condition data meets preset operating conditions; and a second processing module for controlling the first energy storage unit to operate with the required power as a power reference value when the first dispatchable power is greater than or equal to the required power. The operating condition data includes temperature data of the energy storage system and the required power. The temperature data includes the battery body temperature. The preset operating conditions include at least one of the following: the battery body temperature is less than or equal to a preset temperature threshold; the required power is greater than or equal to a preset power threshold.

12. An energy storage system, characterized in that, include: At least two energy storage units connected in parallel, the at least two energy storage units being a first energy storage unit including a sodium battery and a second energy storage unit including a lithium battery, each energy storage unit being connected to a corresponding energy storage converter, and the AC sides of at least two energy storage converters being connected in parallel; a controller connected to the at least two energy storage units, the controller being used to execute the control method of the energy storage system according to any one of claims 1-10.

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