Control method and device based on energy storage system

Abstract

The invention relates to the technical field of energy storage, and discloses a control method and device based on an energy storage system, and the control method comprises the steps: monitoring the operation state of a high-voltage cascade energy storage system; when the high-voltage cascade energy storage system is in a charging mode, the connection mode of the battery units is switched to a series connection mode, and when the high-voltage cascade energy storage system is in a discharging mode, the connection mode of the battery units is switched to a parallel connection mode. According to the energy storage control method provided by the invention, through high-voltage cascade and series charging and parallel discharging technologies, the charging and discharging efficiency of the energy storage system is remarkably improved, the energy loss is reduced, efficient energy storage and release are realized, and meanwhile, the stability and reliability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a control method and device based on an energy storage system. Background Art

[0002] The installed capacity of new energy will usher in a large-scale rapid increase, but new energy power generation has serious randomness and volatility. Once large-scale new energy power generation is connected to the power grid, the frequent power fluctuations it brings will lead to a dynamic imbalance between the active output and load of the power system, posing a severe challenge to the safety and stability of the power system. The energy storage system has fast response speed, strong short-term power throughput, and the ability of two-way regulation and precise tracking. It can play a key role in "peak shaving and valley filling" in new energy power plants, effectively control the power fluctuations of new energy power generation, and ensure the safe and stable operation of the power system. However, traditional energy storage systems have many limitations in terms of energy density, charging and discharging efficiency, and cost. Summary of the invention

[0003] In view of this, the present invention provides a control method and device based on an energy storage system to solve the problems that traditional energy storage systems have many limitations in terms of energy density, charging and discharging efficiency, and cost.

[0004] In a first aspect, the present invention provides an energy storage control method, which is applied to a high-voltage cascade energy storage system. The high-voltage cascade energy storage system adopts a modular design, and each energy storage module includes a plurality of interconnected battery cells. The method comprises:

[0005] Monitor the operating status of the high-voltage cascade energy storage system;

[0006] When the high-voltage cascade energy storage system is in charging mode, the connection mode of the battery cells is switched to a series connection mode, and when the high-voltage cascade energy storage system is in discharging mode, the connection mode of the battery cells is switched to a parallel connection mode.

[0007] The present invention provides an energy storage control method, which significantly improves the charging and discharging efficiency of the energy storage system, reduces energy loss, realizes efficient energy storage and release, and improves the stability and reliability of the system through high-voltage cascade and series charging and discharging technology.

[0008] In an optional embodiment, the method further includes:

[0009] Monitor the voltage of each battery cell in the high-voltage cascade energy storage system;

[0010] Determining whether the voltage of each battery cell meets a first preset requirement;

[0011] When there is a battery cell that does not meet the first preset requirement, starting voltage balancing control and performing energy transfer;

[0012] When the voltage of each battery cell meets the first preset requirement, the voltage balancing control is turned off.

[0013] In an optional embodiment, the method further includes:

[0014] Monitor the charging current of each battery cell in the high-voltage cascade energy storage system;

[0015] Determining whether the charging current of each battery cell meets a second preset requirement;

[0016] When there is a battery cell that does not meet the second preset requirement, starting current balancing control to perform current regulation;

[0017] When the charging current of each battery cell meets the second preset requirement, the current balancing control is turned off.

[0018] In an optional embodiment, the method further includes:

[0019] Monitor the temperature of each battery cell in a high-voltage cascade energy storage system;

[0020] Determining whether the temperature of each battery cell meets a third preset requirement;

[0021] When there is a battery cell that does not meet the third preset requirement, activating the cooling system or the heating system to adjust the temperature;

[0022] When the temperature of each battery cell meets a sixth preset requirement, the cooling system or the heating system is turned off.

[0023] In an optional embodiment, the method further includes:

[0024] Obtain the operating status and operating requirements of the high-voltage cascade energy storage system;

[0025] The power strategy is formulated according to the operating status and operating requirements of the high-voltage cascade energy storage system.

[0026] In an optional implementation, formulating an electricity strategy according to the operating state and operating requirements of the high-voltage cascade energy storage system includes:

[0027] Determine charging or discharging strategy based on real-time electricity price information;

[0028] When the electricity price is lower than a first preset value, controlling the high-voltage cascade energy storage system to charge;

[0029] When the electricity price is higher than a second preset value, the high-voltage cascade energy storage system is controlled to discharge, and the second preset value is greater than the first preset value.

[0030] In an optional implementation, formulating an electricity strategy according to the operating state and operating requirements of the high-voltage cascade energy storage system further includes:

[0031] Determine charging or discharging strategy based on predicted load demand;

[0032] During peak load periods, control the discharge of the high-voltage cascade energy storage system;

[0033] During the off-peak load period, the high-voltage cascade energy storage system is controlled to charge.

[0034] In an optional implementation, formulating an electricity strategy according to the operating state and operating requirements of the high-voltage cascade energy storage system further includes:

[0035] Determine charging or discharging strategies based on renewable energy generation;

[0036] When the power generation of renewable energy is higher than a third preset value, controlling the high-voltage cascade energy storage system to charge;

[0037] When the power generation of renewable energy is lower than a fourth preset value, the high-voltage cascade energy storage system is controlled to discharge, and the fourth preset value is smaller than the third preset value.

[0038] In a second aspect, the present invention provides a high-voltage cascade energy storage system, the system comprising: a control module and a plurality of energy storage modules, wherein:

[0039] The control module is connected to each of the energy storage modules, and the control module is used to execute the energy storage control method of the first aspect or any corresponding embodiment thereof.

[0040] The present invention provides a high-voltage cascade energy storage system, which utilizes an advanced control module to monitor and optimize charging and discharging strategies in real time, thereby ensuring efficient operation and safe and stable operation of the system.

[0041] In an optional embodiment, the control module includes: an energy management system, a plurality of battery array management units, a plurality of battery cluster management units and a plurality of battery management units, wherein:

[0042] The energy management system is communicatively connected with the battery array management unit in each of the energy storage modules via Ethernet;

[0043] In each of the energy storage modules, the battery array management unit is communicatively connected with all of the battery cluster management units, each of the battery cluster management units is communicatively connected with a plurality of the battery management units, and each of the battery management units is connected with a plurality of battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a topological structure diagram of a high-voltage cascade energy storage system according to an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of a battery cluster according to an embodiment of the present invention;

[0047] Figure 3 is a flow chart of an energy storage control method according to an embodiment of the present invention;

[0048] Figure 4 is a control schematic diagram of a high-voltage cascade energy storage system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0050] With the rapid development of renewable energy, the importance of energy storage technology in power systems has become increasingly prominent. Traditional energy storage systems have many limitations in terms of energy density, charging and discharging efficiency, and cost. In order to improve the performance of energy storage systems, the development of new and efficient energy storage technologies has become a research hotspot.

[0051] To this end, the present invention provides an energy storage control method, which is applied to a high-voltage cascade energy storage system. Figure 1 The figure shows the topological structure of the high-voltage cascade energy storage system. The high-voltage cascade energy storage system adopts a modular design. Each energy storage module contains multiple battery clusters, and each battery cluster contains multiple interconnected battery cells. That is, each energy storage module contains multiple interconnected battery cells. Through high-voltage cascading, the energy storage system can achieve high voltage output and reduce transmission loss. Among them, Figure 2 Schematic diagram of a battery cluster.

[0052] According to an embodiment of the present invention, an energy storage control method embodiment is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0053] In this embodiment, an energy storage control method is provided, which is applied to a high-voltage cascade energy storage system. Figure 3 is a flow chart of an energy storage control method according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0054] Step S11, monitoring the operating status of the high-voltage cascade energy storage system.

[0055] Specifically, the control schematic diagram of the high-voltage cascade energy storage system is as follows: Figure 4 As shown. Among them, the BMU (battery management unit) monitors the voltage, current and temperature of each battery cell through sensors, and sends the above data to the BCMS (battery cluster management unit) through the CAN bus. Then, the BAMS (battery array management unit) collects the data of the BCMS through Ethernet, and the EMS (energy management system) collects the data of the BAMS through Ethernet. EMS analyzes the collected data in real time, including battery status, grid electricity price, load demand, etc., to determine the operating status and demand of the high-voltage cascade energy storage system.

[0056] Step S12, when the high-voltage cascade energy storage system is in a charging mode, the connection mode of the battery cells is switched to a series connection mode, and when the high-voltage cascade energy storage system is in a discharging mode, the connection mode of the battery cells is switched to a parallel connection mode.

[0057] Specifically, the high-voltage cascade energy storage system adopts a series charge and discharge control strategy, that is, when charging, the battery cells are connected in series to improve charging efficiency; when discharging, the battery cells are connected in parallel to improve discharge efficiency. According to the operating status and requirements of the high-voltage cascade energy storage system, intelligent switching of the connection mode of the battery cells can achieve efficient energy management. During the charging process, the balancing control circuit is used to ensure that the voltage and current of each battery cell are balanced to avoid overcharging. During the discharging process, the balancing control circuit is used to ensure that the voltage and current of each battery cell are balanced to avoid over-discharge.

[0058] The energy storage control method provided by the present invention significantly improves the charging and discharging efficiency of the energy storage system, reduces energy loss, realizes efficient energy storage and release, and improves the stability and reliability of the system through high-voltage cascade and series charging and discharging technology. By improving energy density and charging and discharging efficiency, the overall cost of the system is reduced and the economy is improved.

[0059] In an optional implementation, the energy storage control method further includes:

[0060] Step S131 , monitoring the voltage of each battery cell in the high-voltage cascade energy storage system.

[0061] Step S132, determining whether the voltage of each battery cell meets a first preset requirement.

[0062] Step S133: when there is a battery cell that does not meet the first preset requirement, voltage balancing control is started to perform energy transfer.

[0063] Step S134: when the voltage of each battery cell meets the first preset requirement, turn off the voltage balancing control.

[0064] Specifically, the BMU monitors the voltage of each battery cell through sensors. The above data is transmitted to the BCMS through the CAN bus. The BCMS collects the data of the BMU and performs real-time analysis to determine which battery cells have voltages that deviate from the set range or are inconsistent with other battery cells. When it is detected that the voltage of some battery cells deviates from the set range or is inconsistent with the voltage of other battery cells, the BCMS sends instructions to the corresponding BMU. The BMU activates the internal balancing circuit to transfer energy. Among them, the energy transfer method generally includes a bypass resistor method and a switch network method. In the bypass resistor method, the high-voltage battery discharges through the bypass resistor and consumes the excess energy in the form of heat energy. In the switch network method, the energy of the high-voltage battery is transferred to the low-voltage battery through the switch network to achieve direct energy transfer. The BMU then continuously monitors the battery status to ensure that the voltage gradually converges. If the voltage is still inconsistent, continue to perform the balancing operation.

[0065] In the embodiment of the present invention, the first preset requirement is that the voltage of the battery cell is within the set range and is consistent with the voltage of other battery cells. The voltage balancing circuit startup conditions include: the system has no fault; the maximum value of the battery cell voltage Vmax ≥ 3.0V; and the battery voltage difference ≥ 30mv. The voltage balancing circuit shutdown conditions include: the system has a serious fault; or the maximum value of the battery cell voltage Vmax ≤ 2.9V; or the battery voltage difference ≤ 18mv.

[0066] Furthermore, the high-voltage cascade energy storage system is also provided with an overcharge protection mechanism and an over-discharge protection mechanism. Among them, the overcharge protection mechanism is: when the battery cell voltage exceeds the set value, the charging circuit is automatically cut off. The over-discharge protection mechanism is: when the battery cell voltage is lower than the set value, the discharge circuit is automatically cut off.

[0067] In an optional implementation, the energy storage control method further includes:

[0068] Step S141, monitoring the charging current of each battery cell in the high-voltage cascade energy storage system.

[0069] Step S142, determining whether the charging current of each battery cell meets a second preset requirement.

[0070] Step S143: when there are battery cells that do not meet the second preset requirement, start current balancing control to perform current regulation.

[0071] Step S144: when the charging current of each battery cell meets the second preset requirement, the current balancing control is turned off.

[0072] Specifically, the BMU monitors the charging current of each battery cell through sensors. The above data is transmitted to the BCMS through the CAN bus. The BCMS collects the data of the BMU, performs real-time analysis, and determines which battery cells have inconsistent charging currents. When inconsistent charging currents are detected, the BCMS sends instructions to the corresponding BMU. The BMU adjusts the charging current distribution to ensure current balance. Among them, the current balancing method includes a dynamic adjustment method and a bypass switch method. In the adjustment method, the output current of the charger is adjusted to make the current evenly distributed among the battery cells. In the bypass switch method, the bypass switch is used to shunt excess current to ensure current balance. The BMU then continuously monitors the battery status to ensure that the current gradually becomes consistent. If the current is still inconsistent, continue to perform the balancing operation. In an embodiment of the present invention, the second preset requirement is that the charging current of the battery cells is consistent.

[0073] In an optional implementation, the energy storage control method further includes:

[0074] Step S151, monitoring the temperature of each battery cell in the high-voltage cascade energy storage system.

[0075] Step S152, determining whether the temperature of each battery cell meets a third preset requirement.

[0076] Step S153: when the third temperature does not satisfy the third preset requirement, the cooling system or the heating system is turned off.

[0077] Specifically, the BMU monitors the temperature of each battery cell through a temperature sensor. The above data is transmitted to the BCMS through the CAN bus. BCMS collects the data of the BMU, performs real-time analysis, and determines which battery cells have inconsistent temperatures. When temperature inconsistency is detected, the BCMS sends an instruction to the corresponding BMU. The BMU activates the cooling system or heating system for temperature adjustment. When the cooling system is started, the temperature of the high-temperature battery is lowered by a fan or a liquid cooling system. When the heating system is on, the temperature of the low-temperature battery is increased by a heating element. The BMU continuously monitors the battery status to ensure that the temperature gradually becomes consistent. If the temperature is still inconsistent, continue to perform the balancing operation. In an embodiment of the present invention, the third preset requirement is that the temperature of the battery cells is consistent.

[0078] Furthermore, the high-voltage cascade energy storage system is also equipped with a temperature protection and safety mechanism: the temperature of the battery cells is monitored in real time. When the temperature exceeds the safe range, the cooling system is started or the circuit is cut off to ensure system safety.

[0079] In an optional implementation, the energy storage control method further includes:

[0080] Step S161, obtaining the operating status and operating requirements of the high-voltage cascade energy storage system.

[0081] Step S162, formulating an electricity strategy according to the operating status and operating requirements of the high-voltage cascade energy storage system.

[0082] Specifically, the high-voltage cascade energy storage system is equipped with an advanced energy management system that monitors the status of each battery cell in real time, including voltage, current, temperature and other parameters. The energy management system optimizes the charging and discharging strategy based on the monitoring data to ensure efficient operation, safety and stability of the system.

[0083] In an optional implementation, step S162 includes:

[0084] Step S1621, determining a charging or discharging strategy based on real-time electricity price information.

[0085] Step S1622, when the electricity price is lower than a first preset value, controlling the high-voltage cascade energy storage system to charge.

[0086] Step S1623, when the electricity price is higher than a second preset value, controlling the high-voltage cascade energy storage system to discharge, the second preset value being greater than the first preset value.

[0087] Specifically, according to the real-time electricity price information, the EMS determines the charging or discharging strategy. When the electricity price is low, the energy storage system is controlled to charge; when the electricity price is high, the energy storage system is controlled to discharge. The first preset value and the second preset value are determined according to the peak and valley of the electricity price.

[0088] In an optional implementation, step S162 further includes:

[0089] Step S1624, determining a charging or discharging strategy based on the predicted load demand.

[0090] Step S1625, during the peak load period, controlling the high-voltage cascade energy storage system to discharge.

[0091] Step S1626, during the off-peak load period, controlling the high-voltage cascade energy storage system to charge.

[0092] Specifically, according to the predicted load demand, EMS will be dispatched in advance. During peak load periods, the energy storage system will be controlled to discharge; during valley load periods, the energy storage system will be controlled to charge.

[0093] In an optional implementation, step S162 further includes:

[0094] Step S1627, determining a charging or discharging strategy according to the renewable energy power generation situation.

[0095] Step S1628, when the power generation of renewable energy is higher than the third preset value, controlling the high-voltage cascade energy storage system to charge.

[0096] Step S1629, when the power generation of renewable energy is lower than a fourth preset value, controlling the high-voltage cascade energy storage system to discharge, the fourth preset value being lower than the third preset value.

[0097] Specifically, according to the renewable energy power generation situation, the EMS adjusts the charging and discharging strategy of the energy storage system. When the renewable energy power generation is sufficient, the energy storage system is controlled to charge; when the renewable energy power generation is insufficient, the energy storage system is controlled to discharge. Among them, the third preset value and the fourth preset value are determined according to the rated power generation of the renewable energy.

[0098] The present invention also provides a high-voltage cascade energy storage system, comprising: a control module and a plurality of energy storage modules, wherein the control module is connected to each energy storage module, and the control module is used to execute the above-mentioned energy storage control method.

[0099] Specifically, the control module includes: EMS, multiple BAMS, multiple BCMS and multiple BMU. Among them, EMS is connected to the BAMS in each energy storage module through Ethernet. In each energy storage module, BAMS is connected to all BCMS, each BCMS is connected to multiple BMUs, and each BMU is connected to multiple battery cells. The schematic diagram of the communication connection between EMS, BAMS, BCMS and BMU is as follows: Figure 4 shown.

[0100] Furthermore, the data collection and analysis process is as follows: BAMS collects BCMS data via Ethernet. BCMS collects BMU data via CAN bus. EMS collects BAMS data via Ethernet. EMS performs real-time analysis on the collected data, including battery status, grid electricity price, load demand, etc. to determine the system's operating status and demand.

[0101] The present invention provides a high-voltage cascade energy storage system, which utilizes an advanced control module to monitor and optimize charging and discharging strategies in real time, thereby ensuring efficient operation and safe and stable operation of the system.

[0102] The process of issuing control instructions is as follows: EMS generates control instructions according to the optimization strategy. The control instructions include parameters such as charging / discharging power and time. EMS sends control instructions to BAMS via Ethernet. BAMS sends control instructions to BCMS via Ethernet. BCMS sends control instructions to BMUBMU via CAN bus to adjust the working state of the H-bridge power module according to the control instructions. The H-bridge power module performs charging or discharging operations.

[0103] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for controlling energy storage, characterized in that: The energy storage control method is applied to a high-voltage cascade energy storage system, wherein the high-voltage cascade energy storage system adopts a modular design, and each energy storage module comprises a plurality of interconnected battery cells. The method comprises: Monitor the operating status of the high-voltage cascade energy storage system; When the high-voltage cascade energy storage system is in charging mode, the connection mode of the battery cells is switched to a series connection mode, and when the high-voltage cascade energy storage system is in discharging mode, the connection mode of the battery cells is switched to a parallel connection mode.

2. The energy storage control method according to claim 1, characterized in that: The method further comprises: Monitor the voltage of each battery cell in the high-voltage cascade energy storage system; Determining whether the voltage of each battery cell meets a first preset requirement; When there is a battery cell that does not meet the first preset requirement, starting voltage balancing control and performing energy transfer; When the voltage of each battery cell meets the first preset requirement, the voltage balancing control is turned off.

3. The energy storage control method according to claim 1, characterized in that: The method further comprises: Monitor the charging current of each battery cell in the high-voltage cascade energy storage system; Determining whether the charging current of each battery cell meets a second preset requirement; When there is a battery cell that does not meet the second preset requirement, starting current balancing control to perform current regulation; When the charging current of each battery cell meets the second preset requirement, the current balancing control is turned off.

4. The energy storage control method according to claim 1, characterized in that: The method further comprises: Monitor the temperature of each battery cell in a high-voltage cascade energy storage system; Determining whether the temperature of each battery cell meets a third preset requirement; When there is a battery cell that does not meet the third preset requirement, activating the cooling system or the heating system to adjust the temperature; When the temperature of each battery cell meets the third preset requirement, the cooling system or the heating system is turned off.

5. The energy storage control method according to claim 1, characterized in that: The method further comprises: Obtain the operating status and operating requirements of the high-voltage cascade energy storage system; The power strategy is formulated according to the operating status and operating requirements of the high-voltage cascade energy storage system.

6. The energy storage control method according to claim 5, characterized in that: The power strategy specified according to the operating status and operating requirements of the high-voltage cascade energy storage system includes: Determine charging or discharging strategy based on real-time electricity price information; When the electricity price is lower than a first preset value, controlling the high-voltage cascade energy storage system to charge; When the electricity price is higher than a second preset value, the high-voltage cascade energy storage system is controlled to discharge, and the second preset value is greater than the first preset value.

7. The energy storage control method according to claim 5, characterized in that: The power strategy specified according to the operating status and operating requirements of the high-voltage cascade energy storage system also includes: Determine charging or discharging strategy based on predicted load demand; During peak load periods, control the discharge of the high-voltage cascade energy storage system; During the off-peak load period, the high-voltage cascade energy storage system is controlled to charge.

8. The energy storage control method according to claim 5, characterized in that: The power strategy specified according to the operating status and operating requirements of the high-voltage cascade energy storage system also includes: Determine charging or discharging strategies based on renewable energy generation; When the power generation of renewable energy is higher than a third preset value, controlling the high-voltage cascade energy storage system to charge; When the power generation of renewable energy is lower than a fourth preset value, the high-voltage cascade energy storage system is controlled to discharge, and the fourth preset value is smaller than the third preset value.

9. A high voltage cascade energy storage system, characterized in that: The system includes: a control module and a plurality of energy storage modules, wherein: The control module is connected to each of the energy storage modules, and the control module is used to execute the energy storage control method according to any one of claims 1 to 8.

10. The high-voltage cascade energy storage system according to claim 9, characterized in that: The control module includes: an energy management system, a plurality of battery array management units, a plurality of battery cluster management units and a plurality of battery management units, wherein: The energy management system is communicatively connected with the battery array management unit in each of the energy storage modules via Ethernet; In each of the energy storage modules, the battery array management unit is communicatively connected with all of the battery cluster management units, each of the battery cluster management units is communicatively connected with a plurality of the battery management units, and each of the battery management units is connected with a plurality of battery cells.

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