Automatic charging method and system for energy storage system

Abstract

The invention relates to an energy storage system automatic charging method and system, and belongs to the technical field of energy storage battery charging. When a set condition is met and the energy storage system needs to be charged, starting to charge the energy storage system through the output of the power plant, otherwise, not charging the energy storage system; the set conditions comprise that the scheduled power of the power grid for the energy storage system in the future set time is smaller than or equal to a set low-power operation power fixed value, and the predicted output power of the power plant in the future set time is larger than or equal to the scheduled power and the output power of the power plant at the current moment. It is ensured that charging of the power plant to the energy storage system in the future set time does not affect support to the power grid and the energy storage system is charged only after sufficient power can be provided by the power plant; the situation that frequent charging and discharging of the energy storage system are finally possibly caused when the generated power is difficult to meet the charging requirements of the power grid and the energy storage system at the same time is avoided.

Description

Technical Field

[0001] This invention relates to an automatic charging method and system for an energy storage system, belonging to the field of energy storage battery charging technology. Background Technology

[0002] New energy storage technologies are receiving increasing attention as they promote the large-scale development and utilization of new energy sources and contribute to the construction of new power systems. With the expanding market demand for new energy storage, the application scope of energy storage projects is also constantly broadening. Currently, numerous models such as "new energy + energy storage," "Internet + energy storage," and "distributed smart grid + energy storage" have emerged, leading to a diversification of energy storage application scenarios. These new application scenarios also bring certain operation and maintenance challenges.

[0003] In the application of energy storage power stations, regardless of whether it's photovoltaic-storage, wind-storage, or thermal-storage combined regulation, dispatch assessment primarily focuses on the grid-connected power of the energy storage station, leveraging its distribution and storage capabilities to support the grid. However, battery operation and maintenance at energy storage stations has always been a pain point in grid support. When power plant output falls short of customer demand for grid-connected power, to maintain grid stability, the energy storage station's AGC (Automatic Generation Control) process involves more battery discharges than charges. This prolonged lack of energy replenishment leads to batteries operating at low SOC (State of Charge), causing battery wear and inaccurate charge readings. This impacts battery lifespan and safety, causing the energy storage station to enter a low-charge protection state. Ultimately, this results in decreased battery performance, affecting energy storage and release, rendering the station unusable as a backup power source.

[0004] Chinese invention patent application CN116111617A proposes a technical solution for an automatic charging method and device for a DC-coupled energy storage system in a photovoltaic power station. This solution automatically charges the energy storage system when the output voltage of the power generation system exceeds a voltage threshold and the energy storage system needs charging. It also dynamically adjusts the charging power of the DC-coupled energy storage system based on customer power demand, prioritizing the use of the remaining power generated by the photovoltaic power generation system to charge the DC-coupled energy storage system. This improves charging efficiency, shortens charging time, and reduces the risk of battery depletion in the energy storage system. However, there are instances where the output voltage of the power generation system is only temporarily above the voltage threshold. In such cases, it is difficult to simultaneously meet the needs of the power grid and the charging needs of the energy storage system. This may result in insufficient power output from the power generation system to the grid, requiring the energy storage system to discharge to the grid. This leads to frequent charging and discharging of the energy storage system, exacerbating the low-power operation of the system, degrading the performance of the batteries in the energy storage station, affecting their energy storage and release, impacting the battery life and safety, and even affecting the reliable support of the power generation system to the grid. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic charging method and system for an energy storage system, in order to solve the problem that current automatic charging methods often encounter situations where the power generation capacity cannot simultaneously meet the needs of the power grid and the charging needs of the energy storage system. This may result in insufficient power output from the power generation system to the power grid, requiring the energy storage system to discharge to the power grid, leading to frequent charging and discharging of the energy storage system.

[0006] To solve the above-mentioned technical problems, the present invention provides an automatic charging method for an energy storage system. When the set conditions are met and the energy storage system needs to be charged, the power plant starts charging the energy storage system through its output; otherwise, the power plant does not charge the energy storage system.

[0007] The set conditions include: the planned power of the grid dispatching the energy storage system within a set future time period is less than or equal to the set low power operation power value, and the predicted output power of the power plant within a set future time period is greater than or equal to the planned power and the current output power of the power plant.

[0008] Furthermore, the setting conditions also include: the difference between the power plant's maximum output power and the power plant's current output power is greater than or equal to the power setpoint for the power plant to charge the energy storage system.

[0009] Furthermore, the methods for obtaining the planned power corresponding to the grid's dispatch of the energy storage system include:

[0010] When a combination of thermal power plants and energy storage systems is used to support the power grid, the corresponding planned power is obtained based on the grid's planned power dispatch to the energy storage system, or based on the grid's planned power dispatch to the thermal power plant.

[0011] When a combination of new energy power plants and energy storage systems is used to support the power grid, the corresponding planned power is obtained based on the power grid's planned power dispatch for the energy storage system.

[0012] Furthermore, the method for determining whether an energy storage system needs charging includes: when the SOC of the energy storage system is less than a first set upper limit value of SOC, it is determined that the energy storage system needs charging; otherwise, it is determined that the energy storage system does not need charging.

[0013] Furthermore, during the charging process of the energy storage system, it is determined in real time whether the SOC of the energy storage system exceeds the second set SOC upper limit. If the SOC of the energy storage system exceeds the second set SOC upper limit, charging of the energy storage system is stopped.

[0014] Furthermore, during the charging process of the energy storage system, charging is stopped when a lockout signal is detected in the energy storage system.

[0015] Furthermore, during the process of charging the energy storage system through the power plant's output, if the energy storage system receives a new dispatch demand command from the grid, and the dispatch demand power in the new dispatch demand command is greater than the original dispatch demand power and the difference between the two exceeds the set demand power change value, the charging of the energy storage system through the power plant's output will be stopped and the energy storage system will be controlled to respond to the new dispatch demand command.

[0016] Beneficial Effects: This invention provides a novel automatic charging method for energy storage systems. This method determines whether to charge the energy storage system by judging whether set conditions are met and whether charging is needed. Specifically, it ensures that the grid's planned power output to the energy storage system within a set future time period is less than or equal to a set low-power operating power threshold. This ensures that the grid's power output to the energy storage system within the set future time period meets the low-power operating conditions (i.e., the energy storage system needs to output very little power to the grid, does not need to participate in peak and valley regulation, and is in an idle state; if the energy storage system needs charging at this time, it can be charged). This guarantees that the power plant's charging of the energy storage system does not affect the grid's support. Furthermore, it determines whether the predicted output power of the power plant within the set future time period is greater than or equal to a set low-power operating power threshold. The invention compares the planned power output with the current power plant output to ensure that the power plant can provide sufficient power to charge the energy storage system within a set future timeframe. This avoids situations where insufficient power is provided during each charge, affecting the grid's support for the power plant, or the energy storage system needs to discharge to the grid before it is fully charged, leading to frequent charging of the energy storage system. The invention only charges the energy storage system after ensuring that the power plant's charging of the energy storage system within the set future timeframe will not affect grid support and that the power plant can provide sufficient power to meet the grid's needs. This avoids situations where the power generation cannot simultaneously meet the grid's demand and the energy storage system's charging needs, potentially resulting in insufficient power output from the power generation system to the grid, requiring the energy storage system to discharge to the grid, and thus leading to frequent charging and discharging of the energy storage system.

[0017] The present invention also provides an automatic charging system for an energy storage system, including a processor, the processor being used to execute a computer program to implement the steps of the above-described automatic charging method for an energy storage system.

[0018] The automatic charging system of this energy storage system can achieve the same beneficial effects as the automatic charging method of the aforementioned energy storage system. Attached Figure Description

[0019] Figure 1 This is a flowchart of the automatic charging method for an energy storage system in an embodiment of the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0021] Example of an automatic charging method for an energy storage system

[0022] This embodiment provides a technical solution for an automatic charging method for an energy storage system. When preset conditions are met and the energy storage system needs charging, charging begins through the power plant's output to the energy storage system; otherwise, charging does not occur. The preset conditions include: the planned power dispatched by the power grid to the energy storage system within a preset future time period is less than or equal to a preset low-power operating power setpoint; and the predicted output power of the power plant within the preset future time period is greater than or equal to the aforementioned planned power and the current power plant output power. This method ensures that charging the energy storage system by the power plant within the preset future time period does not affect the support of the power grid, and that charging only begins when the power plant can provide sufficient power within the preset future time period. This avoids situations where the power generation capacity cannot simultaneously meet the needs of the power grid and the charging needs of the energy storage system, potentially leading to insufficient power output from the power generation system to the grid, requiring the energy storage system to discharge to the grid, and consequently resulting in frequent charging and discharging of the energy storage system.

[0023] The flowchart of the automatic charging method for the energy storage system is as follows: Figure 1 As shown below, a detailed explanation follows:

[0024] When the set conditions are met and the energy storage system needs to be charged, the power plant will start charging the energy storage system through its output; otherwise, it will not charge the energy storage system.

[0025] This setting condition includes: the future setting time (the setting time corresponds to...). Figure 1 The planned power corresponding to the grid's dispatch of the energy storage system within the specified time period (T) is less than or equal to the set low-power operation power setpoint, and the predicted output power of the power plant within the specified time period is greater than or equal to the above planned power and the current output power of the power plant.

[0026] The methods for obtaining the planned power corresponding to the grid's dispatch of energy storage systems include:

[0027] When a combination of thermal power plants and energy storage systems is used to support the power grid, the planned power of the power grid's dispatch to the energy storage system is obtained from the grid's planned power dispatch to the energy storage system, or the planned power of the power grid's dispatch to the thermal power plant is obtained from the grid's planned power dispatch to the energy storage system. This method is used because when a combination of thermal power plants and energy storage systems is used to support the power grid, the planned power dispatch of the energy storage system and the thermal power plant is the same. Therefore, the planned power dispatch of the power grid's dispatch to the energy storage system can be obtained from either the grid's planned power dispatch to the energy storage system or the grid's planned power dispatch to the thermal power plant.

[0028] When a combination of new energy power plants and energy storage systems is used to support the power grid, the planned power of the power grid's dispatch to the energy storage system is obtained based on the planned power of the power grid's dispatch to the energy storage system. This method is used because when a combination of new energy power plants and energy storage systems is used to support the power grid, the planned power of the power grid's dispatch to the new energy power plants is different from the planned power of the power grid's dispatch to the energy storage system. Therefore, the planned power of the power grid's dispatch to the energy storage system is obtained based on the planned power of the power grid's dispatch to the energy storage system.

[0029] In this embodiment, when a combination of thermal power plants and energy storage systems is used to support the power grid, the planned power corresponding to the grid's dispatch of the energy storage system is obtained from either the grid's planned dispatch power for the energy storage system or the grid's planned dispatch power for the thermal power plant. This is done by directly using either the grid's planned dispatch power for the energy storage system or the grid's planned dispatch power for the thermal power plant as the planned power for the grid's dispatch of the energy storage system. In other embodiments, the grid's planned dispatch power for the energy storage system or the grid's planned dispatch power for the thermal power plant can be processed using existing technologies before being used as the planned power for the grid's dispatch of the energy storage system. Similarly, when a combination of new energy power plants and energy storage systems is used to support the power grid, the planned power corresponding to the grid's dispatch of the energy storage system is obtained from either the grid's planned dispatch power for the energy storage system. This is done by directly using the grid's planned dispatch power for the energy storage system. In other embodiments, the grid's planned dispatch power for the energy storage system can be processed using existing technologies before being used as the planned power for the grid's dispatch of the energy storage system.

[0030] Specifically, the planned power dispatch of the power grid to thermal power plants and the planned power dispatch of the power grid to energy storage systems mentioned above are both obtained based on real-time collected data of their respective dispatch planning curves. The planned power dispatched by the power grid to the energy storage system is P. 计划 (and Figure 1 (corresponding to the planned power in the data), the low-power operation power setpoint is P. 低 (and Figure 1 The low value of P corresponds to the predicted output power P of the power plant. 预测 (and Figure 1 The predicted power output (corresponding to the power plant output) is obtained based on real-time collected power plant predicted power curve data. The power plant output power at the current moment is P. 实时 (and Figure 1 (Real-time power in the data).

[0031] Specifically, the above-mentioned method ensures that the grid's dispatch of the energy storage system meets the low-power operation conditions (the energy storage system needs to output very little power to the grid, does not need to participate in the grid's peak and valley regulation, and is in an idle state, and can be charged when needed) by judging whether the planned power corresponding to the grid dispatch of the energy storage system within the future set time is less than or equal to the set low-power operation power value. This ensures that the charging of the energy storage system by the power plant does not affect the support of the grid. By judging whether the predicted output power of the power plant within the future set time is greater than or equal to the planned power and the current output power of the power plant, it ensures that the power plant can provide sufficient power to charge the energy storage system within the future set time. This avoids the situation where each charge cannot provide sufficient power and affects the grid's support for the power plant, and the energy storage system needs to be discharged to the grid before it is fully charged, resulting in frequent charging of the energy storage system.

[0032] The methods for determining whether an energy storage system needs charging include: when the SOC of the energy storage system is less than the first set upper limit value of SOC, the energy storage system needs to be charged; otherwise, the energy storage system does not need to be charged.

[0033] The setting conditions also include: the power plant's maximum output power P 最大 The power plant's current output power P 输出 The difference is greater than or equal to the power setting P for the power plant to charge the energy storage system. 定 By determining whether the power plant's maximum output power P is met. 最大 The power plant's current output power P 输出 The difference is greater than or equal to the power setting P for the power plant to charge the energy storage system. 定 These conditions ensure that the power plant has sufficient power to support the grid connection point. Specifically, the power setpoint P for the power plant to charge the energy storage system... 定 The power output P of the energy storage system is greater than that of the energy storage system. 发 .

[0034] The maximum output power of the power plant corresponding to different energy storage systems is also different. The maximum output power of the power plant corresponding to thermal energy storage is the rated power of the thermal power unit or the maximum output power of the unit; the maximum output power of the power plant corresponding to solar energy storage is the current maximum output power of photovoltaic power; and the maximum output power of the power plant corresponding to wind energy storage is the current maximum output power of wind turbines.

[0035] During the charging process of the energy storage system, it is determined in real time whether the SOC of the energy storage system exceeds the second set SOC upper limit. If the SOC of the energy storage system exceeds the second set SOC upper limit, the charging of the energy storage system is stopped.

[0036] In this embodiment, the SOC of the energy storage system is the average SOC of each battery in the energy storage system.

[0037] During the charging process of the energy storage system, charging will stop when a blocking signal is detected in the energy storage system. Blocking signals include: network interruption, abnormal grid voltage, abnormal grid frequency, and primary frequency regulation blocking.

[0038] During the process of charging the energy storage system through the power plant's output, if the energy storage system receives a new dispatch demand command from the grid, and the dispatch demand power in the new dispatch demand command is greater than the original dispatch demand power and the difference between the two exceeds the set demand power change threshold (i.e., P...), then... ne wP old ≥ΔP and Figure 1 In the context of "real-time dispatch P>= setpoint", when the power plant's output stops charging the energy storage system and the system responds to new dispatch demand commands (i.e., responds to the energy storage system's AGC power regulation), the new dispatch demand command instructs the energy storage system to supply power to the grid. This strategy of limiting grid dispatch demand ensures reliable support from the power plant to the grid.

[0039] Example of an automatic charging system for energy storage system

[0040] This embodiment provides a technical solution for an automatic charging system for an energy storage system. The system includes a processor for executing a computer program to implement the steps of the automatic charging method for an energy storage system described in the above embodiment.

[0041] Since the specific implementation process and principle of the automatic charging system of the energy storage system in this embodiment have been described in detail in the embodiment of the automatic charging method of the energy storage system, they will not be repeated here.

Claims

1. An automatic charging method for an energy storage system, characterized in that, When the set conditions are met and the energy storage system needs to be charged, the power plant will start charging the energy storage system through its output; otherwise, it will not charge the energy storage system. The set conditions include: the planned power of the grid dispatching the energy storage system within a set future time period is less than or equal to the set low power operation power value, and the predicted output power of the power plant within a set future time period is greater than or equal to the planned power and the current output power of the power plant.

2. The automatic charging method for an energy storage system according to claim 1, characterized in that, The setting conditions also include: the difference between the power plant's maximum output power and the power plant's current output power is greater than or equal to the power setting value for the power plant to charge the energy storage system.

3. The automatic charging method for an energy storage system according to claim 1 or 2, characterized in that, The methods for obtaining the planned power corresponding to the grid's dispatch of energy storage systems include: When a combination of thermal power plants and energy storage systems is used to support the power grid, the corresponding planned power is obtained based on the grid's planned power dispatch to the energy storage system, or based on the grid's planned power dispatch to the thermal power plant. When a combination of new energy power plants and energy storage systems is used to support the power grid, the corresponding planned power is obtained based on the power grid's planned power dispatch for the energy storage system.

4. The automatic charging method for an energy storage system according to claim 1 or 2, characterized in that, The methods for determining whether an energy storage system needs charging include: when the SOC of the energy storage system is less than the first set upper limit value of SOC, the energy storage system needs to be charged; otherwise, the energy storage system does not need to be charged.

5. The automatic charging method for an energy storage system according to claim 1 or 2, characterized in that, During the charging process of the energy storage system, it is determined in real time whether the SOC of the energy storage system exceeds the second set SOC upper limit. If the SOC of the energy storage system exceeds the second set SOC upper limit, the charging of the energy storage system is stopped.

6. The automatic charging method for an energy storage system according to claim 1 or 2, characterized in that, During the charging process of the energy storage system, charging will stop when a lockout signal is detected in the energy storage system.

7. The automatic charging method for an energy storage system according to claim 1 or 2, characterized in that, During the process of charging the energy storage system through the output of the power plant, if the energy storage system receives a new dispatch demand command from the grid, and the dispatch demand power in the new dispatch demand command is greater than the original dispatch demand power and the difference between the two exceeds the set demand power change value, the charging of the energy storage system through the output of the power plant will be stopped and the energy storage system will be controlled to respond to the new dispatch demand command.

8. An automatic charging system for an energy storage system, comprising a processor, characterized in that, The processor is used to execute a computer program to implement the steps of the automatic charging method for the energy storage system according to any one of claims 1-7.

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