An energy storage system, a temperature control method, and a photovoltaic power generation system

Abstract

This application provides an energy storage system, a temperature control method, and a photovoltaic power generation system, relating to the field of energy storage system technology. The energy storage system includes at least one energy storage container, each container comprising a temperature control system, a battery cluster, and a controller. The battery cluster includes multiple battery modules connected in series, each module comprising multiple batteries. The controller utilizes the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set of set temperatures of the temperature control system, as well as the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set of set temperatures of the temperature control system, to determine the set temperature of the temperature control system at which the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximized as the target temperature. The temperature control system is used to adjust the temperature inside the energy storage container to the target temperature. Using the solution of this application, the operating efficiency of the energy storage system is improved.

Description

[0001] This application claims priority to Chinese Patent Application No. 202110512546.5, filed on May 11, 2021, entitled "An Energy Storage System, Temperature Control Method and Photovoltaic Power Generation System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of energy storage systems, and more particularly to an energy storage system, a temperature control method, and a photovoltaic power generation system. Background Technology

[0003] With the increasing energy shortages and environmental pollution in modern society, photovoltaic and wind power generation methods have been widely adopted. Furthermore, the development of electrochemical battery technology and the surge in production capacity have led to a decrease in the cost of electrochemical batteries, creating an opportunity for them to participate in energy storage within new energy power generation systems. Due to the flexibility, controllable charging and discharging, rapid response, and high energy density of energy storage systems using electrochemical batteries, their application in various stages of power generation, transmission, transformation, distribution, and consumption is becoming increasingly widespread.

[0004] The temperature control system of the energy storage system is located inside the energy storage container and mainly includes an air conditioner and a fan. The air conditioner is used to regulate the temperature of the battery modules during storage and operation, and the fan is used to regulate the airflow speed. Taking air conditioning for cooling as an example, when the return air temperature of the air conditioner is higher than the set temperature of the temperature control system, the air conditioner operates in cooling mode until the return air temperature reaches the set temperature of the temperature control system, at which point the cooling is complete, and the temperature inside the energy storage container reaches the set temperature of the temperature control system.

[0005] Current solutions typically select the temperature inside the energy storage container corresponding to the maximum available capacity of the battery cluster as the set temperature for the temperature control system. This set temperature is considered the optimal operating temperature for the battery cluster. However, because this solution always maintains the temperature inside the energy storage container at the optimal temperature, it increases the power consumption of the temperature control system and reduces the operating efficiency of the energy storage system. Summary of the Invention

[0006] To address the aforementioned issues, this application provides an energy storage system, a temperature control method, and a photovoltaic power generation system, thereby improving the operating efficiency of the energy storage system.

[0007] Firstly, this application provides an energy storage system. In a typical application scenario, this energy storage system stores electricity during off-peak hours and releases the stored electricity during peak hours. The energy storage system includes at least one energy storage container. Each energy storage container includes a temperature control system, a battery cluster, and a controller. The battery cluster includes multiple battery modules connected in series. Each battery module includes multiple batteries, which can be connected in series or in a mixed-connection manner. The controller utilizes the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature range of the temperature control system, as well as the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature range, to determine the set temperature of the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximized. The temperature control system adjusts the temperature inside the energy storage container to the target temperature.

[0008] The set temperature of the temperature control system, which is the temperature ultimately controlled by the temperature control system within the energy storage container, is also the final operating temperature of the battery cluster. The solution provided in this application considers, on the one hand, the impact of the set temperature of the temperature control system on the usable capacity of the battery cluster when the battery cluster operates at different set temperatures; on the other hand, it also considers the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. Specifically, when the temperature control system is heating, the higher the set temperature, the greater the power consumption, and the lower the set temperature, the less the power consumption. Conversely, when the temperature control system is cooling, the higher the set temperature, the less the power consumption, and the lower the set temperature, the greater the power consumption. The maximum difference between the usable capacity of the battery cluster and the power consumption of the temperature control system indicates the minimum ratio of power consumption to usable capacity, at which point the energy storage system operates at its most efficient. Therefore, using the set temperature of the temperature control system corresponding to the maximum difference between the usable capacity of the battery cluster and the power consumption of the temperature control system as the target temperature, and adjusting the temperature inside the energy storage container to the target temperature, can improve the operating efficiency of the energy storage system.

[0009] In one possible implementation, the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system is pre-calibrated and stored under different operating states of the battery cluster.

[0010] In practical applications, the correspondence between the available capacity of the battery cluster at different charging rates and multiple different set temperatures in the temperature control system's set temperature set can be pre-calibrated during battery cluster charging; the correspondence between the available capacity of the battery cluster at different discharge rates and multiple different set temperatures in the temperature control system's set temperature set can be pre-calibrated during battery cluster discharging; and the correspondence between the available capacity of the battery cluster at different states of charge and multiple different set temperatures in the temperature control system's set temperature set when the battery cluster is in a quiescent state can be pre-calibrated. The corresponding correspondence can be determined based on the current operating state of the battery cluster, fully considering the impact of different operating states of the battery cluster on the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the temperature control system's set temperature set.

[0011] In one possible implementation, when the battery cluster is charging, the controller determines the correspondence between the available capacity of the battery cluster at the current charging rate and multiple different set temperatures in the set temperature set of the temperature control system. When the battery cluster is discharging, it determines the correspondence between the available capacity of the battery cluster at the current discharging rate and multiple different set temperatures in the set temperature set of the temperature control system. When the battery cluster is in a quiescent state, it determines the correspondence between the available capacity of the battery cluster at the current state of charge and multiple different set temperatures in the set temperature set of the temperature control system.

[0012] That is, the controller determines the corresponding relationship based on the current working state of the battery cluster.

[0013] In one possible implementation, the temperature control system includes multiple air conditioners and multiple fans. The fans regulate the airflow velocity around multiple battery modules. The air conditioners regulate the temperature inside the energy storage container. Specifically, the controller determines the correspondence between the total power consumption of the activated air conditioners and multiple different set temperatures in the set temperature set of the temperature control system, and determines the total power consumption of the activated fans. Based on the correspondence between the total power consumption of the activated air conditioners and the multiple different set temperatures in the set temperature set of the temperature control system, and the total power consumption of the activated fans, the controller further determines the correspondence between the power consumption of the temperature control system and the multiple different set temperatures in the set temperature set of the temperature control system.

[0014] The power consumption of the temperature control system is the power consumption of all the air conditioners that are turned on and the power consumption of all the fans that are turned on. The controller determines these two power consumptions separately and then adds them together to determine the power consumption of the temperature control system.

[0015] In one possible implementation, all fans are activated, and the controller determines the fan speeds based on the temperatures of the multiple battery modules. The total power consumption of the multiple fans is determined based on the total number of fans and their respective speeds.

[0016] The fan speed is determined by the battery module temperature. When the air conditioner is cooling, the higher the battery module temperature, the higher the fan speed; the lower the battery module temperature, the lower the fan speed. Conversely, when the air conditioner is heating, the lower the battery module temperature, the higher the fan speed; and vice versa. The relationship between fan speed and battery module temperature can be preset. The relationship between the speed of a single fan and its power consumption can also be preset.

[0017] In one possible implementation, the controller determines the number of fans to be activated and their rotational speed based on the temperatures of multiple battery modules. The total power consumption of the activated fans is then determined based on the number of fans activated and their rotational speeds.

[0018] The number of fans activated is determined by the battery module's temperature. When the air conditioner is cooling, the higher the battery module temperature, the more fans are activated; the lower the battery module temperature, the fewer fans are activated. When the air conditioner is heating, the lower the battery module temperature, the more fans are activated; the higher the battery module temperature, the fewer fans are activated. The relationship between the number of fans activated and the battery module temperature can be preset.

[0019] In one possible implementation, the controller determines the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system, and determines the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system.

[0020] Then, based on the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, the correspondence between the number of air conditioners to be turned on and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0021] The controller then determines the total power consumption of the air conditioners and the relationship between the different set temperatures in the temperature control system based on the correspondence between the number of air conditioners turned on and the set temperatures in the temperature control system, as well as the correspondence between the power consumption of a single air conditioner and the set temperatures in the temperature control system.

[0022] In one possible implementation, when the controller determines the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system, it uses the solar radiation intensity and the outer surface area of ​​the energy storage container to determine the heat transferred to the energy storage container by solar thermal radiation; it uses the heat transfer coefficient of the energy storage container, the outer surface area of ​​the energy storage container, and the current temperature outside the energy storage container to determine the correspondence between the heat transferred from the outside of the energy storage container to the inside of the energy storage container by heat conduction and multiple different set temperatures in the set temperature set of the temperature control system; and it uses the operating time of multiple battery modules, the operating current of multiple battery modules, the internal resistance of multiple battery modules, and the open circuit voltage of multiple battery modules to determine the heat generated by multiple battery modules during operation.

[0023] The controller adds up the heat from the above three parts to determine the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature of the temperature control system.

[0024] In one possible implementation, the controller determines the operating time and operating current of multiple battery modules based on the received operating information.

[0025] This operational information is sent by the controller's host computer, which can be a Smart Array Control Unit (SACU).

[0026] In one possible implementation, the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, corresponding to different temperatures outside the energy storage container, is pre-calibrated and stored. The controller determines the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, corresponding to the current temperature outside the energy storage container.

[0027] In one possible implementation, the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the temperature control system's set temperature set, corresponding to different temperatures outside the energy storage container, is pre-calibrated and stored. The controller determines the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the temperature control system's set temperature set, corresponding to the current temperature outside the energy storage container.

[0028] In one possible implementation, the number of fans is the same as the number of battery modules, with one fan used to regulate the gas flow rate around a corresponding battery module.

[0029] In order to ensure that the temperature of each battery module is even, multiple fans are usually set to be turned on at the same time and at the same speed.

[0030] In one possible implementation, the controller includes a first control unit and multiple second control units. The number of second control units is the same as the number of fans, and each second control unit controls the operating status of a corresponding fan. The first control unit controls the operating status of multiple air conditioners.

[0031] The first control unit can be a container monitoring unit (CMU), and the second control unit can be a battery monitoring unit (BMU). Each second control unit can also monitor the operating status of a corresponding battery module, such as detecting the temperature and SOC of the corresponding battery module.

[0032] In one possible implementation, a second control unit is also used to detect the temperature of a corresponding battery module and send the temperature detection result of the battery module to the first control unit.

[0033] In one possible implementation, the energy storage system further includes a first temperature sensor. The first temperature sensor is located outside the energy storage container. The first temperature sensor is used to detect the temperature outside the energy storage container and send the detection result to the controller.

[0034] Based on the current temperature outside the energy storage container, the controller determines the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, as well as the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system.

[0035] Secondly, this application also provides a temperature control method for an energy storage system, which is applied to the energy storage system provided in the above implementation, and the method includes:

[0036] By utilizing the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system, as well as the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature set of the temperature control system, the set temperature of the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximized is determined as the target temperature.

[0037] Adjust the temperature inside the energy storage container to the target temperature.

[0038] This method considers the impact of the set temperature of the temperature control system on the usable capacity of the battery cluster when it operates under different set temperatures, and also takes into account the impact of the set temperature on the power consumption of the temperature control system. The system operates at its highest efficiency when the difference between the usable capacity of the battery cluster and the power consumption of the temperature control system is at its maximum. Therefore, using the set temperature of the temperature control system corresponding to the maximum difference between the usable capacity of the battery cluster and the power consumption of the temperature control system as the target temperature, and adjusting the temperature inside the energy storage container to the target temperature, can improve the operating efficiency of the energy storage system.

[0039] In one possible implementation, before determining the target temperature by utilizing the relationship between the available capacity of the battery cluster and the set temperature of the temperature control system, and the relationship between the power consumption of the temperature control system and the set temperature of the temperature control system, the method further includes:

[0040] The relationship between the available capacity of the battery cluster and the set temperature of the temperature control system under different operating conditions of the battery cluster is pre-calibrated and stored.

[0041] Specifically, the system can pre-calibrate the correspondence between the available capacity of the battery cluster at different charging rates and multiple different set temperatures in the temperature control system's set temperature set during battery cluster charging; pre-calibrate the correspondence between the available capacity of the battery cluster at different discharge rates and multiple different set temperatures in the temperature control system's set temperature set during battery cluster discharging; and pre-calibrate the correspondence between the available capacity of the battery cluster at different states of charge and multiple different set temperatures in the temperature control system's set temperature set when the battery cluster is in a quiescent state. Therefore, it fully considers the impact of different operating states of the battery cluster on the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the temperature control system's set temperature set.

[0042] In one possible implementation, the method further includes:

[0043] When the battery cluster is charging, determine the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system at the current charging rate.

[0044] When the battery cluster is in a discharging state, determine the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system at the current discharge rate.

[0045] When the battery cluster is in a quiescent state, determine the correspondence between the available capacity of the battery cluster under the current state of charge and multiple different set temperatures in the set temperature set of the temperature control system.

[0046] In one possible implementation, the method further includes:

[0047] Determine the correspondence between the total power consumption of the air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, and determine the total power consumption of the fan that is turned on.

[0048] Based on the correspondence between the total power consumption of the air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, as well as the total power consumption of the fan, the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0049] The power consumption of the temperature control system is determined by summing the power consumption of all the air conditioners and all the fans that are turned on.

[0050] In one possible implementation, all fans are started, and the total power consumption of the activated fans is determined, specifically including:

[0051] The fan speed is determined based on the temperature of multiple battery modules;

[0052] The total power consumption of the multiple fans is determined based on the total number of fans and their rotational speeds.

[0053] In this implementation, the relationship between the fan speed and the battery module temperature can be preset. The relationship between the speed of a single fan and the power consumption of a single fan is also preset.

[0054] In one possible implementation, determining the total power consumption of the activated fan specifically includes:

[0055] The number of fans to be turned on and the speed of the fans to be turned on are determined based on the temperature of multiple battery modules.

[0056] The total power consumption of the operating fans is determined based on the number of fans turned on and their rotational speed.

[0057] In this implementation, the relationship between the number of fans turned on and the temperature of the battery module can be preset.

[0058] In one possible implementation, the correspondence between the total power consumption of the activated air conditioner and multiple different set temperatures in the set temperature set of the temperature control system is determined, specifically including:

[0059] Determine the correspondence between the total cooling capacity required for the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system;

[0060] Determine the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system;

[0061] Based on the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, the correspondence between the number of air conditioners to be turned on and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0062] Based on the correspondence between the number of air conditioners turned on and the multiple different set temperatures in the temperature control system's set temperature set, as well as the correspondence between the power consumption of a single air conditioner and the multiple different set temperatures in the temperature control system's set temperature set, the total power consumption of the turned-on air conditioners and the correspondence between the multiple different set temperatures in the temperature control system's set temperature set are determined.

[0063] In one possible implementation, the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set of set temperatures of the temperature control system is determined, specifically including:

[0064] The amount of heat transferred from solar radiation to the energy storage container is determined by using the intensity of solar radiation and the outer surface area of ​​the energy storage container.

[0065] By using the heat transfer coefficient of the energy storage container, the outer surface area of ​​the energy storage container, and the current temperature outside the energy storage container, the correspondence between the heat transferred from the outside of the energy storage container to the inside of the energy storage container through heat conduction and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0066] The heat generated by multiple battery modules during operation is determined by using the operating time, operating current, internal resistance, and open-circuit voltage of multiple battery modules.

[0067] By utilizing the heat transferred to the energy storage container by solar thermal radiation, the heat transferred to the energy storage container from the outside of the energy storage container through thermal conduction, the correspondence between multiple different set temperatures in the set temperature set of the temperature control system, and the heat generated when multiple battery modules are working, the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0068] In one possible implementation, before determining the heat generated by the multiple battery modules during operation using the operating time, operating current, internal resistance, and open-circuit voltage of the multiple battery modules, the method further includes:

[0069] It is used to determine the operating time and operating current of multiple battery modules based on the received operating information.

[0070] In one possible implementation, before determining the correspondence between the total power consumption of the air conditioners and the multiple different set temperatures in the set temperature set of the temperature control system, based on the correspondence between the number of air conditioners turned on and the multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the power consumption of a single air conditioner and the multiple different set temperatures in the set temperature set of the temperature control system, the method further includes:

[0071] The power consumption of a single air conditioner and the correspondence between multiple different set temperatures in the set temperature set of the temperature control system are pre-calibrated and stored for different temperatures outside the energy storage container.

[0072] Determine the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, corresponding to the current temperature outside the energy storage container.

[0073] In one possible implementation, before determining the correspondence between the total power consumption of the air conditioners and the multiple different set temperatures in the set temperature set of the temperature control system, based on the correspondence between the number of air conditioners turned on and the multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the power consumption of a single air conditioner and the multiple different set temperatures in the set temperature set of the temperature control system, the method further includes:

[0074] The power consumption of a single air conditioner and the correspondence between multiple different set temperatures in the set temperature set of the temperature control system are pre-calibrated and stored for different temperatures outside the energy storage container.

[0075] Determine the correspondence between the power consumption of a single air conditioner and the set of multiple different set temperatures in the temperature control system, corresponding to the current temperature outside the energy storage container.

[0076] Thirdly, this application also provides a photovoltaic power generation system, which includes the energy storage system provided in the above-described implementation, and further includes a photovoltaic inverter, an AC bus, and multiple photovoltaic modules. The multiple photovoltaic modules are connected to the input terminal of the photovoltaic inverter, the output terminal of the photovoltaic inverter is connected to the AC bus, and the AC bus connects the energy storage system and the AC power grid. The photovoltaic modules utilize solar energy to generate direct current (DC) and transmit the DC to the photovoltaic inverter. The photovoltaic inverter converts the DC to AC and provides it to the AC power grid through the AC bus, and / or charges the energy storage system. The energy storage system of this photovoltaic power generation system considers the impact of the set temperature of the temperature control system on the usable capacity of the battery cluster when the battery cluster operates at different set temperatures; it also considers the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. When the difference between the usable capacity of the battery cluster and the power consumption of the temperature control system is at its maximum, it indicates that the ratio of the power consumption of the temperature control system to the usable capacity of the battery cluster is at its minimum, and the energy storage system operates at its highest efficiency. Therefore, the target temperature is the temperature set by the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is the largest. By adjusting the temperature inside the energy storage container to the target temperature, the operating efficiency of the energy storage system can be improved, thereby improving the operating efficiency of the photovoltaic power generation system. Attached Figure Description

[0077] Figure 1 This is a schematic diagram of a new energy power generation system;

[0078] Figure 2 A schematic diagram of an energy storage system provided in an embodiment of this application;

[0079] Figure 3 A graph illustrating the relationship between the usable capacity of an illustrative battery and the set temperature of a temperature control system, provided for an embodiment of this application.

[0080] Figure 4 A graph showing the relationship between the power consumption of the temperature control system during cooling and the set temperature of the temperature control system provided in the embodiments of this application;

[0081] Figure 5 A graph showing the relationship between the power consumption of the temperature control system during heating and the set temperature of the temperature control system provided in this application embodiment;

[0082] Figure 6 Schematic diagram of the principle provided for the embodiments of this application Figure 1 ;

[0083] Figure 7 Schematic diagram of the principle provided for the embodiments of this application Figure 2 ;

[0084] Figure 8A schematic diagram of another energy storage system provided in the embodiments of this application;

[0085] Figure 9 A flowchart illustrating a temperature control method for an energy storage system provided in this application embodiment;

[0086] Figure 10 A flowchart illustrating another temperature control method for an energy storage system provided in this application embodiment;

[0087] Figure 11 A flowchart illustrating a method for determining the correspondence between the power consumption of a temperature control system and multiple different set temperatures in a set of set temperatures provided in this application embodiment.

[0088] Figure 12 A schematic diagram of a photovoltaic power generation system provided in an embodiment of this application;

[0089] Figure 13 A schematic diagram of a photovoltaic power generation terminal provided in an embodiment of this application;

[0090] Figure 14 This is a schematic diagram of another photovoltaic power generation terminal provided in an embodiment of this application. Detailed Implementation

[0091] To enable those skilled in the art to better understand the technical solutions provided in the embodiments of this application, the application scenarios of the technical solutions provided in this application will be introduced first below.

[0092] See Figure 1 The figure is a schematic diagram of a new energy power generation system.

[0093] The new energy power generation system includes a battery cluster 10, a power conversion circuit 20, a new energy power generation terminal 30, and a load 40.

[0094] The new energy generation terminal 30 generates alternating current (AC). Due to the volatility and uncertainty of the new energy generation terminal 30, its power generation fluctuates. When the AC output from the new energy generation terminal 30 exceeds the power demand of the AC grid 50, the excess power is converted into direct current (DC) by the power conversion circuit 20 to charge the battery cluster 10. When the AC output from the new energy generation terminal 30 is lower than the power demand of the AC grid 50, the power conversion circuit 20 converts the DC output from the battery cluster 10 back into AC and outputs it to the AC grid 50 to stabilize the AC grid 50.

[0095] Taking the new energy power generation terminal 30 as an example of a photovoltaic power generation terminal, the new energy power generation terminal 30 includes photovoltaic modules and a direct current (DC) / alternating current (AC) conversion circuit (which can also be called an inverter circuit or inverter). The photovoltaic modules use light energy to generate direct current, and the DC / AC conversion circuit converts the direct current into alternating current and outputs it to the AC grid 50 and / or charges the battery cluster 10 through the power conversion circuit 20.

[0096] Load 40 is an electrical device in the new energy power generation system. Load 40 includes a temperature control system, specifically including an air conditioner and a fan. Load 40 may also include other equipment, such as lighting equipment, etc., but this application embodiment does not specifically limit it.

[0097] The battery cluster 10 includes multiple battery modules connected in series, and each battery module includes multiple battery cells connected in series or in a mixed manner. The batteries can be lithium-ion batteries, lead-acid batteries, supercapacitors, or combinations thereof, and this application does not specifically limit them.

[0098] The energy storage system of the new energy power generation terminal 30 includes battery clusters 10, power conversion circuits 20, and temperature controller systems. The battery clusters 10 and the temperature control system are located inside the energy storage container.

[0099] Battery capacity refers to the amount of electrical energy a battery can store. As batteries are used, their capacity decreases, meaning the actual usable capacity often differs from the initial capacity. A significant factor contributing to battery capacity degradation is the temperature of the operating environment.

[0100] Current temperature control systems aim to maintain the temperature of the energy storage container at the optimal operating temperature of the battery clusters, where battery capacity degradation is minimized, thus maximizing the usable capacity of the battery clusters. However, this approach increases the power consumption of the temperature control system, thereby reducing the operating efficiency of the energy storage system.

[0101] To address the above issues, this application provides an energy storage system, a temperature control method for the energy storage system, and a photovoltaic power generation system. It considers the impact of the set temperature of the temperature control system on the available capacity of the battery cluster, as well as the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. When the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximized, the set temperature of the corresponding temperature control system is set as the target temperature. The temperature control system then adjusts the temperature inside the energy storage container to this target temperature, thereby improving the operating efficiency of the energy storage system.

[0102] The technical solution of this application will be described below with reference to the accompanying drawings.

[0103] The terms "first," "second," etc., used in the following description of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0104] In this application, unless otherwise expressly specified and limited, the term "connection" shall be interpreted broadly. For example, "connection" may be a fixed connection, a detachable connection, or an integral part; it may be a direct connection or an indirect connection through an intermediate medium.

[0105] See Figure 2 The figure is a schematic diagram of an energy storage system provided in an embodiment of this application.

[0106] The energy storage system includes at least one energy storage container 300, which includes a battery cluster 10a1, a temperature control system 301, and a controller 302.

[0107] Among them, the battery cluster 10a1 includes multiple battery modules connected in series. The battery cluster 10a1 shown in the figure includes m battery modules, which are numbered 101a1 to 101am.

[0108] Each battery module includes multiple batteries, and the batteries in the battery module can be connected in series or in a mixed manner. This application does not make specific limitations. The illustration shows the batteries connected in series as an example.

[0109] The temperature control system 301 is used to regulate the temperature inside the energy storage container. After the set temperature of the temperature control system is determined, the temperature control system 301 cools or heats the container to achieve that set temperature. Therefore, the set temperature can be understood as the desired temperature inside the energy storage container, or as the desired operating environment temperature for the battery clusters.

[0110] The solutions in this application take into account the impact of different temperature control system settings on the available capacity of the battery cluster, as well as the impact of different temperature control system settings on the power consumption of the temperature control system, which will be described below.

[0111] The following section first explains the impact of different temperature control system set temperatures on the available capacity of the battery cluster. Here, the available capacity of the battery cluster refers to the currently remaining usable capacity of the battery cluster.

[0112] The capacity of a battery cluster is the sum of the capacities of all the cells. By analyzing the relationship between the available capacity of a single cell and the set temperature of the temperature control system, the relationship between the available capacity of the battery cluster and the set temperature of the temperature control system can be determined.

[0113] See Figure 3The figure is a schematic graph showing the relationship between the available capacity of a battery and the set temperature of a temperature control system, provided in an embodiment of this application.

[0114] Because the set temperature of the temperature control system, that is, the temperature that the temperature control system ultimately aims to control the energy storage container to reach, also represents the temperature of the battery's operating environment. Therefore... Figure 3 It also characterizes the relationship between the battery's usable capacity and the battery's operating temperature.

[0115] Depend on Figure 3 It can be determined that the battery's usable capacity is related to the set temperature of the temperature control system. When the battery operates at its optimal temperature, the capacity degradation is minimal, and the usable capacity is at its highest.

[0116] The following explains the impact of the set temperature of the temperature control system on the power consumption of the temperature control system.

[0117] See Figure 4 The figure shows the relationship between the power consumption of the temperature control system during cooling and the set temperature of the temperature control system provided in the embodiment of this application.

[0118] The data points in the figure represent the relationship between the set temperature of different temperature control systems and the power consumption of the temperature control system when it is cooling. The range of the set temperature should cover the normal operating temperature range of the battery and should also be within the temperature control capability range of the temperature control system. When the set temperature is uniformly selected, the interval between set temperature values ​​can be determined by the temperature control accuracy of the temperature control system.

[0119] Fitting the above data points into a relationship curve shows that when the temperature control system is cooling, the lower the set temperature of the temperature control system, that is, the lower the temperature inside the energy storage container needs to be adjusted by the temperature control system, the higher the power consumption of the temperature control system; when the set temperature of the temperature control system increases, the temperature control system adjusts the temperature inside the energy storage container to a relatively higher temperature, and the power consumption of the temperature control system decreases.

[0120] See Figure 5 The figure shows the relationship between the power consumption of the temperature control system during heating and the set temperature of the temperature control system provided in the embodiment of this application.

[0121] The data points in the figure represent the relationship between the set temperature of different temperature control systems and the power consumption of the temperature control system when it is heating. The range of the set temperature should cover the normal operating temperature range of the battery and should also be within the temperature control capability range of the temperature control system. When the set temperature is uniformly selected, the interval between set temperature values ​​can be determined by the temperature control accuracy of the temperature control system.

[0122] Fitting the above data points into a relationship curve shows that when the temperature control system is heating, the lower the set temperature of the temperature control system, that is, the lower the temperature inside the energy storage container is adjusted by the temperature control system, the lower the power consumption of the temperature control system. When the set temperature of the temperature control system increases, the temperature control system adjusts the temperature inside the energy storage container to a relatively higher temperature, and the power consumption of the temperature control system increases.

[0123] The controller 302 of this application for the energy storage container utilizes the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system, as well as the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature set of the temperature control system, to determine the set temperature of the temperature control system corresponding to the maximum difference between the available capacity of the battery cluster and the power consumption of the temperature control system as the target temperature, so that the temperature control system adjusts the temperature inside the energy storage container to the target temperature. The principle of this scheme is explained in detail below.

[0124] Let's take refrigeration using a temperature control system as an example.

[0125] See Figure 6 This figure is a schematic diagram of the principle provided in the embodiment of this application. Figure 1 .

[0126] The set of set temperatures in the temperature control system includes multiple different set temperatures. This application embodiment does not specifically limit the range, number, or temperature interval of the set temperatures. In some embodiments, the range of set temperatures covers the temperature range for normal battery operation, and the set temperatures should also be within the temperature control capability range of the temperature control system. When the set temperatures are uniformly selected, the number of set temperatures is related to the temperature interval. In this application embodiment, when setting the temperature interval, the temperature control accuracy of the temperature control system can be referenced. For example, if the accuracy is 1°C, the temperature interval can be set to 1°C; or, if the accuracy is 0.1°C, the temperature interval can be set to 0.1°C or a multiple of 0.1°C, etc.

[0127] The correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system can be pre-calibrated experimentally and stored in the form of a data table.

[0128] The available capacity of the battery cluster is fitted to a curve by relating it to multiple different set temperatures in the temperature control system's set temperature set. This curve is shown in Figure 2. Each data point on curve 2 represents the available capacity of the battery cluster at that set temperature. This curve 2... Figure 3 The curve corresponds to this.

[0129] The power consumption of the temperature control system during cooling is fitted to a curve by relating it to multiple different set temperatures within the set temperature range of the temperature control system. This curve is shown as curve 1 in the figure. Each data point on curve 1 represents the power consumption of the temperature control system at that set temperature. Figure 4 The curve in the image corresponds to this.

[0130] The difference between curve 2 and curve 1 represents the difference between the available capacity of the battery cluster and the power consumption of the temperature control system. The largest possible difference indicates the smallest ratio of power consumption by the temperature control system to the available capacity of the battery cluster, signifying the highest operating efficiency of the energy storage system.

[0131] The temperature control system's setpoint, T2, corresponds to the maximum difference shown in the diagram. The optimal operating temperature for the battery cluster is T1. When the temperature control system maintains the temperature inside the energy storage container at the target temperature T2, the available capacity of the battery cluster is often not at its maximum. Instead, by appropriately reducing the available capacity, the setpoint temperature of the temperature control system can be increased. This increase in the setpoint temperature reduces the power consumption of the temperature control system during cooling. Therefore, the overall difference between the available capacity of the battery cluster and the power consumption of the temperature control system reaches its maximum, thereby improving the operating efficiency of the energy storage system.

[0132] The following explains the principle of the temperature control system when it is heating.

[0133] See Figure 7 This figure is a schematic diagram of the principle provided in the embodiment of this application. Figure 2 .

[0134] The available capacity of the battery cluster is fitted to a curve by relating it to multiple different set temperatures in the temperature control system's set temperature set. This curve is shown in Figure 2. Each data point on curve 2 represents the available capacity of the battery cluster at that set temperature. This curve 2... Figure 3 The curve corresponds to this.

[0135] The power consumption of the temperature control system during heating is fitted to a curve with the correspondence between multiple different set temperatures in the set temperature range of the temperature control system. This curve is shown as curve 3 in the figure. Each data point on curve 3 represents the power consumption of the temperature control system at that set temperature. Curve 3 and... Figure 5 The curve in the image corresponds to this.

[0136] The difference between curve 2 and curve 3 is the difference between the available capacity of the battery cluster and the power consumption.

[0137] The largest difference indicates that the ratio of the power consumption of the temperature control system to the available capacity of the battery cluster is the smallest, and the energy storage system operates at its highest efficiency.

[0138] The temperature control system's set temperature, T3, corresponds to the maximum difference shown in the diagram. The optimal operating temperature for the battery cluster is T1. When the temperature control system maintains the temperature inside the energy storage container at the target temperature T3, the available capacity of the battery cluster is often not at its maximum. Instead, by appropriately reducing the available capacity of the battery cluster, the set temperature of the temperature control system can be lowered to a certain extent. Lowering the set temperature reduces the power consumption of the temperature control system during heating. Therefore, the overall difference between the available capacity of the battery cluster and the power consumption of the temperature control system reaches its maximum, improving the operating efficiency of the energy storage system.

[0139] The controller 302 described above can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a digital signal processor (DSP), or a combination thereof. Specifically, the PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof; this application does not specifically limit this.

[0140] In summary, the embodiments of this application provide a controller for an energy storage system, which determines the set temperature of the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is the largest, and sets the set temperature of the temperature control system as the target temperature, so that the temperature control system can adjust the temperature inside the energy storage container to the target temperature, thereby reducing the energy consumption of the temperature control system and improving the operating efficiency of the energy storage system.

[0141] The technical solution of this application will be explained below with reference to specific implementation methods.

[0142] The temperature control system of the energy storage container includes multiple air conditioners and multiple fans. This application embodiment does not limit the specific number of air conditioners and fans. The power consumption of the temperature control system is the sum of the power consumption of all activated air conditioners and all activated fans.

[0143] Air conditioning is used to regulate the temperature inside the energy storage container by cooling or heating, that is, to regulate the temperature of the working environment of the battery clusters. In practical applications, in order to achieve uniform temperature within the container, the air conditioners are generally evenly distributed inside the energy storage container.

[0144] The fan is used to regulate the airflow speed around multiple battery modules, so the fan can be positioned close to the battery modules.

[0145] The following describes the process by which the controller determines the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature range of the temperature control system.

[0146] The following section explains how the controller determines the power consumption of the fan that is turned on.

[0147] The power consumption of the running fans is mainly determined by the number of running fans and their rotational speed.

[0148] The fan speed is determined by the battery module temperature. When the air conditioner is cooling, the higher the battery module temperature, the higher the fan speed; the lower the battery module temperature, the lower the fan speed. When the air conditioner is heating, the lower the battery module temperature, the higher the fan speed; the higher the battery module temperature, the lower the fan speed. The relationship between the fan speed and the battery module temperature can be preset.

[0149] The relationship between the rotational speed of a single fan and its power consumption is predetermined and stored. In some embodiments, the relationship between the rotational speed of a single fan and its power consumption is stored in the form of a data table.

[0150] In some embodiments, the number of fans is the same as the number of battery modules. Each fan is used to regulate the airflow speed around a corresponding battery module. To ensure uniform temperature across all battery modules, all fans are typically set to be on. The controller determines the fan speed based on the battery module temperature. Once the fan speed is determined, the power consumption Q of a single fan at that speed can be determined based on the relationship between the fan speed and the power consumption of a single fan. a The controller determines the number of fans turned on (n1) and the power consumption (Q) of each fan based on the number of fans activated. a The total power consumption Q of the fan when it is turned on is determined by the following formula. 风扇 :

[0151] Q 风扇 =n1*Q a (1)

[0152] Since all the fans are turned on at this time, the value of n1 in equation (1) is the total number of fans.

[0153] In other embodiments, to reduce fan power consumption, only some fans may be turned on. The number of fans turned on is determined by the battery module temperature. When the air conditioner is cooling, the higher the battery module temperature, the more fans are turned on; the lower the battery module temperature, the fewer fans are turned on. When the air conditioner is heating, the lower the battery module temperature, the more fans are turned on; the higher the battery module temperature, the fewer fans are turned on. The relationship between the number of fans turned on and the battery module temperature can be preset.

[0154] The controller determines the number of fans to activate based on the battery module's temperature, and also determines the speed of each fan based on the battery module's temperature. After determining the speed of each fan, the controller can determine the power consumption Q of each fan at that speed by analyzing the relationship between the fan speed and the fan's power consumption. a The controller determines the number of fans turned on (n1) and the power consumption (Q) of each fan based on the number of fans activated. a The total power consumption Q of the fan when it is turned on is determined by equation (1). 风扇 In this case, n1 in equation (1) is the number of fans that are turned on.

[0155] The following explains the process by which the controller determines the total power consumption of the air conditioner and the correspondence between multiple different set temperatures in the set temperature set of the temperature control system.

[0156] The following explanation will first take the air conditioner cooling as an example. The principle is similar when the air conditioner is heating, and will not be repeated in the embodiments of this application.

[0157] The controller first determines the total refrigerating capacity Q required by the current energy storage container. 制冷 This refers to the correspondence between multiple different set temperatures in the set temperature set of the temperature control system. Cooling capacity refers to the total amount of heat removed from a closed space per unit time when the air conditioner is cooling.

[0158] Total cooling capacity Q 制冷 This mainly includes the energy Q1 transferred from solar thermal radiation to the energy storage container, the heat Q2 transferred from the outside of the energy storage container to the inside of the energy storage container through thermal conduction, and the heat Q3 generated when multiple battery modules are working.

[0159] For ease of explanation, the following example illustrates the following scenario: the temperature control system starts adjusting the temperature inside the energy storage container from time t1; the battery modules in the energy storage container are in a silent state (neither charging nor discharging) from time t1 to time t2; and the battery modules in the energy storage container are working (charging or discharging) from time t2 to time t3.

[0160] The energy Q1 of solar thermal radiation can be determined by the following formula:

[0161]

[0162] In equation (2), a is the solar radiation coefficient, S is the solar radiation intensity, and F is the outer surface area of ​​the energy storage container.

[0163] The heat Q2 transferred from the outside of the energy storage container to the inside of the energy storage container via thermal conduction can be determined by the following formula:

[0164]

[0165] In equation (3), K is the heat transfer coefficient of the energy storage container, F is the outer surface area of ​​the energy storage container, and T is the heat transfer coefficient of the energy storage container. 外 T represents the current temperature outside the energy storage container. 设定温度 The set temperature is the temperature of the temperature control system. Therefore, different Q2 can be determined according to different set temperatures in the set temperature set. That is, equation (3) represents the correspondence between the heat Q2 transferred from the outside of the energy storage container to the inside of the energy storage container through heat conduction and multiple different set temperatures in the set temperature set of the temperature control system.

[0166] The heat Q3 generated when multiple battery modules are working can be determined by the following formula:

[0167]

[0168] The battery cluster includes m battery modules, the battery module's operating current is I, the battery module's internal resistance is R, and the battery module's open circuit voltage (OCV) is OCV1.

[0169] The internal resistance R of the battery module can be pre-calibrated and stored through testing. For example, the internal resistance of a single battery can be pre-calibrated after a battery aging cycle test, and then the internal resistance of the battery module can be calibrated based on the internal resistance of the single battery.

[0170] The open-circuit voltage OCV1 of the battery module can be pre-calibrated and stored through testing.

[0171] In some embodiments, the controller can receive operating information sent by the host computer, determine the operating time of multiple battery modules based on the operating information, that is, determine the above-mentioned time t2 and time t3, and determine the operating current I of multiple battery modules.

[0172] Based on equations (1) to (3) above, determine the total refrigeration capacity Q required for the current energy storage container. 制冷 The correspondence between multiple different set temperatures in the set temperature set of the temperature control system is shown in the following formula:

[0173] Q制冷 =Q1+Q2+Q3 (5)

[0174] The controller then determines the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system. The cooling capacity of a single air conditioner is related to the temperature outside the energy storage container and the set temperature of the temperature control system. The solution in this application pre-calibrates and stores the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, corresponding to different temperatures outside the energy storage container.

[0175] In this application embodiment, the range of temperature outside the energy storage container and the value of the temperature interval are not specifically limited. In some embodiments, the range of temperature outside the energy storage container should cover the range of ambient temperature variation at the location where the energy storage container is installed. The value of the temperature interval can refer to the temperature control accuracy of the temperature control system. For example, if the accuracy is 1°C, the temperature interval can be set to 1°C; or if the accuracy is 0.1°C, the temperature interval can be set to 0.1°C or a multiple of 0.1°C, etc.

[0176] The controller determines the temperature T outside the energy storage container based on the current temperature. 外 Determine the temperature T 外 The corresponding relationship between the cooling capacity Q0 of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system.

[0177] In some embodiments, the energy storage system further includes a first temperature sensor disposed on the exterior of the energy storage container. The first temperature sensor is used to detect the temperature outside the energy storage container and send the detection result to the controller.

[0178] The controller is based on the total cooling capacity Q. 制冷 Based on the correspondence between multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the cooling capacity Q0 of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, the correspondence between the number of air conditioners turned on (n2) and multiple different set temperatures in the set temperature set of the temperature control system is determined. Here, n2 is a positive integer, which can be determined by the following formula:

[0179]

[0180] That is, n2 is a pair of Q 制冷 The result is the quotient after dividing by Q0 and rounding up. Rounding up is used to ensure that a sufficient number of air conditioners are turned on. The controller then determines the power consumption of a single air conditioner and the correspondence between multiple different set temperatures in the set temperature set of the temperature control system.

[0181] Specifically, the power consumption of a single air conditioner is related to the temperature outside the energy storage container and the set temperature of the temperature control system. The solution in this application pre-calibrates and stores the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the set of set temperatures of the temperature control system, corresponding to different temperatures outside the energy storage container.

[0182] In this application embodiment, the range of temperature outside the energy storage container and the value of the temperature interval are not specifically limited. In some embodiments, the range of temperature outside the energy storage container should cover the range of ambient temperature variation at the location where the energy storage container is installed. The value of the temperature interval can refer to the temperature control accuracy of the temperature control system. For example, if the accuracy is 1°C, the temperature interval can be set to 1°C; or if the accuracy is 0.1°C, the temperature interval can be set to 0.1°C or a multiple of 0.1°C, etc.

[0183] The controller determines the temperature T outside the energy storage container based on the current temperature. 外 Determine the temperature T 外 The corresponding power consumption Q of a single air conditioner b The correspondence between multiple different set temperatures in the set temperature set of the temperature control system.

[0184] The controller then determines the correspondence between the number of air conditioners (n2) turned on and the different set temperatures in the temperature control system's set temperature set, as well as the power consumption (Q) of a single air conditioner. b The total power consumption Q of the air conditioner is determined by establishing the correspondence between multiple different set temperatures in the set temperature set of the temperature control system. 空调 The correspondence between multiple different set temperatures in the set temperature set of the temperature control system is shown in the following formula:

[0185] Q 空调 =n2*Q b (6)

[0186] The total power consumption Q of the fan that will be turned on 风扇 Total power consumption Q of the air conditioner when it is turned on 空调 Adding them together, we get the total power consumption Q of the temperature control system. 系统 See the following formula for details:

[0187] Q 系统 =Q 风扇 +Q 空调 (7)

[0188] Equation (7) characterizes the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set of set temperatures of the temperature control system, corresponding to Figure 4 The curve shown.

[0189] To enable real-time measurement of the temperature inside and outside the energy storage container, the energy storage system also includes a first temperature sensor and a second temperature sensor. The first temperature sensor is located inside the energy storage container to detect the temperature inside the container and send the detection result to the controller. The second temperature sensor is located outside the energy storage container to detect the ambient temperature outside the container and send the detection result to the controller.

[0190] It is understandable that, since the air conditioner is used for cooling in the temperature control system, the set temperature of the temperature control system is also the set temperature of the air conditioner in practical applications.

[0191] The above explanation establishes the correspondence between the power consumption of the temperature control system and the various set temperatures within the set temperature range of the air conditioner when it is cooling. The principle is similar when the air conditioner is heating; the established correspondence corresponds to... Figure 5 The curves shown are not described in detail in this embodiment of the application.

[0192] The following describes how the controller determines the correspondence between the available capacity of the battery cluster in the current operating state and multiple different set temperatures in the set temperature set of the temperature control system.

[0193] The solution in this application pre-calibrates and stores the correspondence between the available capacity of the battery cluster under different operating states and multiple different set temperatures in the set temperature set of the temperature control system. Then, the controller determines the correspondence between the available capacity of the corresponding battery cluster and multiple different set temperatures in the set temperature set of the temperature control system based on the current operating state of the battery cluster, as described in detail below.

[0194] The battery clusters in an energy storage system can operate in charging, discharging, and quiescent states (i.e., neither charging nor discharging). Furthermore, when charging, the battery clusters can be charged at different rates; when discharging, they can be discharged at different rates; and when quiescent, the battery clusters can be in different states of charge (SOC).

[0195] The charging rate is a measure of how fast the battery pack charges, while the discharging rate is a measure of how fast it discharges. The higher the rate, the greater the charging or discharging current of the battery pack, and the shorter the time it takes for the battery pack to complete charging and discharging.

[0196] SOC is the ratio of the remaining charge of a battery cluster to its current available capacity, usually expressed as a percentage. Therefore, the value range of SOC is [0, 1].

[0197] The solution provided in this application pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different charging rates and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is charging; pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different discharge rates and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is discharging; and pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different states of charge and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is in a quiescent state.

[0198] The values ​​of the charging rate and discharging rate are determined by the configuration of the energy storage system, and this application embodiment does not impose specific limitations on them. The range of the State of Charge (SOC) value is [0, 1], and this application embodiment does not impose limitations on the specific value interval of the SOC.

[0199] When the controller determines that the battery cluster is in a charging state, it further determines the correspondence between the available capacity of the battery cluster at the current charging rate and multiple different set temperatures in the set temperature set of the temperature control system; when it determines that the battery cluster is in a discharging state, it further determines the correspondence between the available capacity of the battery cluster at the current discharging rate and multiple different set temperatures in the set temperature set of the temperature control system; when it determines that the battery cluster is in a quiescent state, it further determines the correspondence between the available capacity of the battery cluster at the current state of charge and multiple different set temperatures in the set temperature set of the temperature control system.

[0200] The above correspondence is stored in a memory, which includes, but is not limited to, phase-change RAM (PRAM), static random-access memory (SRAM), dynamic random-access memory (DRAM), and other types of random access memory (RAM), and can also be electrically erasable programmable read-only memory (EEPROM), etc.

[0201] The controller described above in the embodiments of this application can be a single-level controller or a combination of multiple-level controllers. When the controller is a multi-level controller, the higher-level controller can control the lower-level controller. The controller can be independently integrated on a printed circuit board (PCB), or it can be physically divided into multiple parts and respectively set on a PCB in different locations in the energy storage system, with each part working together to achieve the control function. The implementation method when the controller is a multi-level controller is described in detail below.

[0202] See Figure 8 The figure is a schematic diagram of another energy storage system provided in an embodiment of this application.

[0203] An energy storage system typically consists of multiple energy storage containers 300; only one of these containers 300 is shown in the figure.

[0204] The controller of the energy storage system includes a first control unit 3021, a second control unit 3022, and a battery control unit (BCU) 3023.

[0205] The number of second control units 3022 is the same as the number of fans, and each second control unit 3022 is used to control the operating status of a corresponding fan. In some embodiments, the second control unit 3022 is a battery monitoring unit (BMU), and each second control unit 3022 is used to monitor the operating status of a corresponding battery module, such as detecting the temperature and SOC of the corresponding battery module. The second control unit 3022 is also used to send the detection results of temperature, SOC, etc. to the first control unit 3021.

[0206] The first control unit 3021 is used to control the operating status of multiple air conditioners. In some embodiments, the first control unit 3021 is a container monitoring unit (CMU).

[0207] The first control unit 3021 and the second control unit 3022 communicate through the battery control unit 3023. That is, the first control unit 3021 sends control information to each of the second control units 3022 through each of the battery control units 3023, so that each of the second control units 3022 controls the corresponding fan according to the control information.

[0208] The energy storage container 300 includes battery clusters 10a1 to 10am, each battery cluster being connected to a corresponding Direct Current (DC) / DC converter circuit 303. The DC / DC converter circuit 303 converts the DC power output from the battery clusters into DC power before outputting it to the outside of the energy storage container, or converts DC power obtained from outside the energy storage container into DC power to charge the battery clusters. A battery control unit 3023 can be integrated with the DC / DC converter circuit 303 to control the operating state of the corresponding DC / DC converter circuit 303.

[0209] The subarray controller 400 of the energy storage system is used to control the operating status of each energy storage container 300. The subarray controller 400 can interact with the first control unit 3021. In some embodiments, the subarray controller 400 is a Smart Array Control Unit (SACU).

[0210] The first control unit 3021 can obtain the operating information sent by the subarray controller 400, determine the time until the battery is next charged or discharged, and the operating current of the battery based on the operating information, and then determine the energy consumption of the temperature control system.

[0211] In summary, the energy storage system provided in this application takes into account the impact of the set temperature of the temperature control system on the available capacity of the battery cluster when the battery cluster operates at different set temperatures, and also considers the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. The set temperature of the temperature control system corresponding to the maximum difference between the available capacity of the battery cluster and the power consumption of the temperature control system is taken as the target temperature, and the temperature control system adjusts the temperature inside the energy storage container to the target temperature. At this time, the ratio of the power consumption of the temperature control system to the available capacity of the battery cluster is minimized, thus improving the operating efficiency of the energy storage system.

[0212] Based on the energy storage system provided in the above embodiments, this application also provides a temperature control method for the energy storage system, which will be described in detail below with reference to the accompanying drawings.

[0213] See Figure 9 The figure is a flowchart of a temperature control method for an energy storage system provided in an embodiment of this application.

[0214] For details on the specific implementation of the energy storage system, please refer to the relevant descriptions in the above embodiments; these will not be repeated here. The method includes the following steps:

[0215] S501: By utilizing the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature set of the temperature control system, the set temperature of the temperature control system at which the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximized is determined as the target temperature.

[0216] S502: Adjust the temperature inside the energy storage container to the target temperature.

[0217] The method provided in this application takes into account the impact of the set temperature of the temperature control system on the usable capacity of the battery cluster when the battery cluster operates at different set temperatures, and also considers the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. When the difference between the usable capacity of the battery cluster and the power consumption of the temperature control system is at its maximum, it indicates that the ratio of the power consumption of the temperature control system to the usable capacity of the battery cluster is at its minimum, and the energy storage system operates at its highest efficiency. Therefore, by using the set temperature of the temperature control system corresponding to the maximum difference between the usable capacity of the battery cluster and the power consumption of the temperature control system as the target temperature, and by adjusting the temperature control system to the temperature inside the energy storage container to the target temperature, the operating efficiency of the energy storage system can be improved.

[0218] The following section will first explain in detail the method for determining the correspondence between the available capacity of the battery cluster under its current state and multiple different set temperatures in the set temperature set of the temperature control system.

[0219] See Figure 10 The figure is a flowchart of another temperature control method for an energy storage system provided in an embodiment of this application.

[0220] The method includes the following steps:

[0221] S501a: Pre-calibrate and store the relationship between the available capacity of the battery cluster and the set temperature of the temperature control system under different operating conditions of the battery cluster.

[0222] The method provided in this application pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different charging rates and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is charging; pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different discharge rates and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is discharging; and pre-calibrates the correspondence between the available capacity of the battery cluster corresponding to different states of charge and multiple different set temperatures in the set temperature set of the temperature control system when the battery cluster is in a quiescent state.

[0223] The values ​​of the charging rate and discharging rate are determined by the configuration of the energy storage system, and this application embodiment does not impose specific limitations on them. The range of the State of Charge (SOC) value is [0, 1], and this application embodiment does not impose limitations on the specific value interval of the SOC.

[0224] S501b: Determine the current operating status of the battery cluster.

[0225] S501c: When the battery cluster is in a charging state, determine the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system at the current charging rate.

[0226] S501d: When the battery cluster is in a discharging state, determine the correspondence between the available capacity of the battery cluster and multiple different set temperatures in the set temperature set of the temperature control system at the current discharge rate.

[0227] S501e: When the battery cluster is in a quiescent state, determine the correspondence between the available capacity of the battery cluster under the current state of charge and multiple different set temperatures in the set temperature set of the temperature control system. The method for determining the energy consumption of the current temperature control system is described below.

[0228] See Figure 11 The figure is a flowchart of a method for determining the correspondence between the power consumption of a temperature control system and multiple different set temperatures in the set temperature set of the temperature control system, provided in an embodiment of this application.

[0229] The temperature control system includes multiple air conditioners and multiple fans. The fans are used to regulate the airflow speed around the battery modules, and the air conditioners are used to regulate the temperature inside the energy storage container. The method includes the following steps:

[0230] S501f: Determine the correspondence between the total power consumption of the air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, and determine the total power consumption of the fan that is turned on.

[0231] The following describes the method for determining the total power consumption of the air conditioner and the correspondence between multiple different set temperatures in the set temperature set of the temperature control system.

[0232] First, we will take the air conditioner cooling as an example. The principle is similar when the air conditioner is heating, so we will not repeat it in this embodiment.

[0233] First, determine the correspondence between the total cooling capacity required by the current energy storage container and the various set temperatures in the set temperature set of the temperature control system.

[0234] The total cooling capacity mainly includes the energy transferred to the energy storage container by solar thermal radiation, the heat transferred from the outside of the energy storage container to the energy storage container through thermal conduction, and the heat generated when multiple battery modules are working.

[0235] The amount of heat transferred from solar radiation to the energy storage container is determined by using the solar radiation intensity and the outer surface area of ​​the energy storage container. The heat transfer coefficient, outer surface area, and current outside temperature of the energy storage container are used to determine the relationship between the amount of heat transferred from the outside of the energy storage container to the inside of the energy storage container through heat conduction and the set of multiple different set temperatures in the temperature control system. The amount of heat generated by multiple battery modules during operation is determined by using the operating time, operating current, internal resistance, and open circuit voltage of multiple battery modules.

[0236] Based on the heat transferred from solar thermal radiation to the energy storage container, the heat transferred from the outside of the energy storage container to the energy storage container through thermal conduction, the correspondence between multiple different set temperatures in the set temperature set of the temperature control system, and the heat generated when multiple battery modules are working, the correspondence between the total cooling capacity required by the energy storage container and multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0237] In some embodiments, the operating time and operating current of the multiple battery modules can be obtained from the operating information sent by the host computer. The internal resistance of the battery modules can be pre-calibrated and stored through testing, for example, the internal resistance of a single battery can be pre-calibrated after a battery aging cycle experiment, and then the internal resistance of the battery module can be calibrated based on the internal resistance of the single battery. Similarly, the open-circuit voltage of the battery modules can be pre-calibrated and stored through testing.

[0238] Then, the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system is determined. The cooling capacity of a single air conditioner is related to both the temperature outside the energy storage container and the set temperature of the temperature control system. In this embodiment, the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, corresponding to different temperatures outside the energy storage container, is pre-calibrated and stored.

[0239] This application does not specifically limit the range of temperature outside the energy storage container or the value of the temperature interval. In some embodiments, the range of temperature outside the energy storage container should cover the range of ambient temperature variation at the location where the energy storage container is installed. The value of the temperature interval can refer to the temperature control accuracy of the temperature control system. For example, if the accuracy is 1°C, the temperature interval can be set to 1°C; or if the accuracy is 0.1°C, the temperature interval can be set to 0.1°C or a multiple of 0.1°C, etc.

[0240] Determine the correspondence between the cooling capacity of a single air conditioner corresponding to the current temperature outside the energy storage container and the set of multiple different set temperatures in the temperature control system's set temperature set.

[0241] The controller determines the correspondence between the number of air conditioners to be turned on and the multiple different set temperatures in the set temperature set of the temperature control system based on the correspondence between the total cooling capacity and multiple different set temperatures in the set temperature set of the temperature control system, and the correspondence between the cooling capacity of a single air conditioner and multiple different set temperatures in the set temperature set of the temperature control system.

[0242] The number of air conditioners turned on is rounded up to ensure that a sufficient number of air conditioners are turned on. Then, the correspondence between the power consumption of a single air conditioner and the multiple different set temperatures in the set temperature set of the temperature control system is determined.

[0243] Specifically, the power consumption of a single air conditioner is related to the temperature outside the energy storage container and the set temperature of the temperature control system. The solution in this application pre-calibrates and stores the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the set of set temperatures of the temperature control system, corresponding to different temperatures outside the energy storage container.

[0244] In this application embodiment, the range of temperature outside the energy storage container and the value of the temperature interval are not specifically limited. In some embodiments, the range of temperature outside the energy storage container should cover the range of ambient temperature variation at the location where the energy storage container is installed. The value of the temperature interval can refer to the temperature control accuracy of the temperature control system. For example, if the accuracy is 1°C, the temperature interval can be set to 1°C; or if the accuracy is 0.1°C, the temperature interval can be set to 0.1°C or a multiple of 0.1°C, etc.

[0245] Then determine the power consumption Q of a single air conditioner corresponding to the current temperature outside the energy storage container. b The correspondence between multiple different set temperatures in the set temperature set of the temperature control system.

[0246] Based on the correspondence between the number of air conditioners turned on and multiple different set temperatures in the temperature control system's set temperature set obtained through the above process, as well as the correspondence between the power consumption of a single air conditioner and multiple different set temperatures in the temperature control system's set temperature set, the correspondence between the total power consumption of the turned-on air conditioners and multiple different set temperatures in the temperature control system's set temperature set is determined.

[0247] The following explains how to determine the power consumption of a fan that is turned on.

[0248] The power consumption of the running fans is mainly determined by the number of running fans and their rotational speed.

[0249] The fan speed is determined by the battery module temperature. When the air conditioner is cooling, the higher the battery module temperature, the higher the fan speed; the lower the battery module temperature, the lower the fan speed. When the air conditioner is heating, the lower the battery module temperature, the higher the fan speed; the higher the battery module temperature, the lower the fan speed. The relationship between the fan speed and the battery module temperature can be preset.

[0250] The relationship between the rotational speed of a single fan and its power consumption is predetermined and stored. In some embodiments, the relationship between the rotational speed of a single fan and its power consumption is stored in the form of a data table.

[0251] In some embodiments, the number of fans is the same as the number of battery modules. Each fan is used to regulate the airflow speed around a corresponding battery module. To ensure uniform temperature across all battery modules, all fans are typically set to be on. The fan speed is determined based on the temperature of the battery modules. Once the fan speed is determined, the power consumption of a single fan at that speed can be determined by the relationship between the fan speed and the power consumption of a single fan. Based on the total number of fans and the power consumption of each fan, the total power consumption of the activated fans can be determined.

[0252] In other embodiments, to reduce fan power consumption, only some fans may be activated. The number of fans activated in this case is determined by the battery module temperature. When the air conditioner is cooling, the higher the battery module temperature, the more fans are activated; the lower the battery module temperature, the fewer fans are activated. When the air conditioner is heating, the lower the battery module temperature, the more fans are activated; the higher the battery module temperature, the fewer fans are activated. The relationship between the number of fans activated and the battery module temperature can be preset. The number of fans activated is determined based on the battery module temperature, and the rotational speed of each fan is also determined based on the battery module temperature. After the controller determines the rotational speed of each fan, the power consumption of each fan at that rotational speed can be determined based on the relationship between the rotational speed and the power consumption of each fan. Based on the number of fans activated and the power consumption of each fan, the total power consumption of the activated fans is determined.

[0253] S501g: Based on the correspondence between the total power consumption of the air conditioner and multiple different set temperatures in the set temperature set of the temperature control system, and the total power consumption of the fan, determine the correspondence between the power consumption of the temperature control system and multiple different set temperatures in the set temperature set of the temperature control system.

[0254] The division and order of the steps in the embodiments of this application are only for the convenience of explanation and do not constitute a limitation on the method of this application. Those skilled in the art can make adjustments according to the actual situation.

[0255] In summary, the temperature control method for the energy storage system provided in this application reduces the operating energy consumption of the temperature control system and improves the operating efficiency of the energy storage system.

[0256] Based on the energy storage system provided in the above embodiments, this application also provides a photovoltaic power generation system, which will be described in detail below with reference to the accompanying drawings.

[0257] See Figure 12 The figure is a schematic diagram of a photovoltaic power generation system provided in an embodiment of this application.

[0258] The photovoltaic power generation system shown in the diagram includes: an energy storage system and a photovoltaic power generation terminal 60.

[0259] The energy storage system includes at least one energy storage container 300, at least one power conversion system (PCS) 200, and an AC bus.

[0260] Power conversion system 200 corresponds to Figure 1 The power conversion circuit 20 in the middle.

[0261] The AC bus includes the positive AC bus (marked as P in the diagram) and the negative AC bus (marked as N in the diagram).

[0262] The specific implementation of the energy storage container 300 can be found in the relevant descriptions in the above embodiments, and will not be repeated here.

[0263] In some embodiments, an energy storage container 300 and a power conversion system 200 are connected to form an energy storage branch, and the energy storage system includes at least one energy storage branch.

[0264] In other embodiments, the number of energy storage containers 100 and power conversion systems 200 varies.

[0265] The power conversion system 200 is a bidirectional DC / AC converter, which can be equipped with a neutral point clamped T-type three-level circuit, a neutral point clamped (NPC) circuit, an active neutral point clamped (ANPC) circuit, a flying capacitor multilevel circuit, etc.

[0266] Since the port voltage of a single battery cell varies with the energy storage capacity, the port output voltage of the battery cluster inside the energy storage container 300 is a wide range of output voltages. Therefore, in order to match the range of changes in the port voltage of the battery cluster, the power conversion system 200 typically has a wide range of input and output capabilities.

[0267] See Figure 13 The figure is a schematic diagram of a photovoltaic power generation terminal provided in an embodiment of this application.

[0268] The photovoltaic power generation end shown in the diagram includes a photovoltaic module 601, a DC combiner box 602, and a photovoltaic inverter 603.

[0269] The photovoltaic module 601 is used to generate direct current (DC) using solar energy. The input of the DC combiner box 602 is typically connected to multiple photovoltaic modules 601, and the output of the DC combiner box 602 is connected to the photovoltaic inverter 603. The photovoltaic modules 601 transmit the generated DC power to the photovoltaic inverter through the DC combiner box 602.

[0270] The output of the photovoltaic inverter 603 is connected to the AC bus. The AC bus also connects to the energy storage system and the AC grid. The photovoltaic inverter 603 is used to convert direct current (DC) to alternating current (AC) and transmit it to the grid via the AC bus, or to charge the energy storage system.

[0271] See Figure 14 This figure is a schematic diagram of another photovoltaic power generation terminal provided in an embodiment of this application.

[0272] Figure 14 The photovoltaic power generation system shown is Figure 13 The difference lies in that the photovoltaic module 601 first outputs DC power to the boost combiner box 604. The boost combiner box 604 has maximum power point tracking (MPPT) functionality and is a type of DC boost converter.

[0273] In practical applications, Figure 13 and Figure 14 The number of three-phase photovoltaic inverters 803 in the scenario can be one or more, and this application embodiment does not specifically limit the number.

[0274] The photovoltaic (PV) power generation terminal 60 exhibits volatility and uncertainty, resulting in fluctuations in its power generation. When the AC power output from the PV power generation terminal 60 exceeds the electricity demand of the AC grid 50, the excess power is converted to DC power via the AC bus and power conversion system 200 to charge the battery clusters in the energy storage system. When the AC power output from the PV power generation terminal 60 is lower than the electricity demand of the AC grid 50, the battery clusters in the energy storage system output DC power. This DC power is then converted back to AC power by the power conversion system 200 of the energy storage system before being output to the AC grid 50, thus stabilizing the AC grid 50.

[0275] In summary, this photovoltaic power generation system considers the impact of the set temperature of the temperature control system on the usable capacity of the battery clusters when they operate at different set temperatures; it also considers the impact of the set temperature of the temperature control system on the power consumption of the temperature control system. The system achieves its highest operating efficiency when the difference between the usable capacity of the battery clusters and the power consumption of the temperature control system is at its maximum. Therefore, using the set temperature of the temperature control system corresponding to the maximum difference between the usable capacity of the battery clusters and the power consumption of the temperature control system as the target temperature, and adjusting the temperature inside the energy storage container to the target temperature, can improve the operating efficiency of the energy storage system, thereby improving the operating efficiency of the photovoltaic power generation system.

[0276] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0277] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. Furthermore, some or all of the units and modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0278] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An energy storage system, characterized by, The energy storage system comprises at least one energy storage container, each of the energy storage containers comprising a temperature control system, a battery cluster and a controller; The battery cluster comprises a plurality of battery modules connected in series, each of the battery modules comprising a plurality of batteries; The controller is configured to determine a target temperature of the temperature control system by using a correspondence between available capacity of the battery cluster and a plurality of different set temperatures in a set of set temperatures of the temperature control system, and a correspondence between power consumption of the temperature control system and the plurality of different set temperatures in the set of set temperatures of the temperature control system, wherein the set temperature of the temperature control system corresponding to a maximum difference between the available capacity of the battery cluster and the power consumption of the temperature control system is the target temperature; and the set temperature of the temperature control system corresponding to a minimum ratio between the power consumption of the temperature control system and the available capacity of the battery cluster is the target temperature. The temperature control system is configured to adjust a temperature in the energy storage container to the target temperature.

2. The energy storage system of claim 1, wherein, The correspondence between the available capacity of the battery cluster and the plurality of different set temperatures in the set of set temperatures of the temperature control system under different working states of the battery cluster is pre-calibrated and stored.

3. The energy storage system of claim 2, wherein, The controller is specifically configured to: determine the correspondence between the available capacity of the battery cluster and the plurality of different set temperatures in the set of set temperatures of the temperature control system under a current charging rate when the battery cluster is in a charging state; determine the correspondence between the available capacity of the battery cluster and the plurality of different set temperatures in the set of set temperatures of the temperature control system under a current discharging rate when the battery cluster is in a discharging state; and determine the correspondence between the available capacity of the battery cluster and the plurality of different set temperatures in the set of set temperatures of the temperature control system under a current state of charge when the battery cluster is in a silent state.

4. The energy storage system of any one of claims 1-3, wherein, The temperature control system comprises a plurality of air conditioners and a plurality of fans; The plurality of fans are configured to adjust a flow speed of gas around the plurality of battery modules; The plurality of air conditioners are configured to adjust a temperature in the energy storage container; The controller is specifically configured to determine a correspondence between a total power consumption of the started air conditioners and the plurality of different set temperatures in the set of set temperatures of the temperature control system, and determine a total power consumption of the started fans, and determine the correspondence between the power consumption of the temperature control system and the plurality of different set temperatures in the set of set temperatures of the temperature control system according to the correspondence between the total power consumption of the started air conditioners and the plurality of different set temperatures in the set of set temperatures of the temperature control system, and the total power consumption of the started fans.

5. The energy storage system of claim 4, wherein, When all the plurality of fans are started, the controller is specifically configured to: determine a rotating speed of the plurality of fans according to temperatures of the plurality of battery modules; and determine the total power consumption of the plurality of fans according to a total number of the plurality of fans and the rotating speed of the plurality of fans.

6. The energy storage system of claim 4, wherein, The controller is specifically configured to: determine a number of started fans and a rotating speed of the started fans according to the temperatures of the plurality of battery modules. Determine the total power consumption of the opened air conditioners according to the number of opened air conditioners and the rotating speed of the opened air conditioners.

7. The energy storage system of claim 4, wherein, The controller is specifically configured to: Determine the correspondence between the total refrigeration capacity required by the energy storage container and the plurality of different set temperatures in the set temperature collection of the temperature control system; Determine the correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system; Determine the correspondence between the number of opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the correspondence between the total refrigeration capacity required by the energy storage container and the plurality of different set temperatures in the set temperature collection of the temperature control system, and the correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system; Determine the correspondence between the total power consumption of the opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the correspondence between the number of opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system, and the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system.

8. The energy storage system of claim 7, wherein, The controller is specifically configured to: Determine the heat transferred to the energy storage container by solar radiation according to the solar radiation intensity and the outer surface area of the energy storage container; Determine the correspondence between the heat transferred to the energy storage container from the outside of the energy storage container by heat conduction and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the heat transfer coefficient of the energy storage container, the outer surface area of the energy storage container, and the current temperature outside the energy storage container; Determine the heat generated by the plurality of battery modules during operation according to the working time of the plurality of battery modules, the working current of the plurality of battery modules, the internal resistance of the plurality of battery modules, and the open-circuit voltage of the plurality of battery modules; Determine the correspondence between the total refrigeration capacity required by the energy storage container and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the heat transferred to the energy storage container by solar radiation, the heat transferred to the energy storage container from the outside of the energy storage container by heat conduction, and the correspondence between the plurality of different set temperatures in the set temperature collection of the temperature control system, and the heat generated by the plurality of battery modules during operation.

9. The energy storage system of claim 8, wherein, The controller is specifically configured to determine the working time of the plurality of battery modules and the working current of the plurality of battery modules according to the received operation information.

10. The energy storage system of claim 7, wherein, The correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to different temperatures outside the energy storage container is pre-calibrated and stored; The controller is specifically configured to determine the correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to the current temperature outside the energy storage container. The correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to different temperatures outside the energy storage container is pre-calibrated and stored; The controller is specifically configured to determine the correspondence between the refrigeration capacity of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to the current temperature outside the energy storage container.

11. The energy storage system of claim 7, wherein, The correspondence between the power consumption of a single air conditioner and different set temperatures of the temperature control system corresponding to different temperatures outside the energy storage container is pre-calibrated and stored; The controller is specifically configured to determine the correspondence between the power consumption of a single air conditioner and different set temperatures of the temperature control system corresponding to the current temperature outside the energy storage container.

12. The energy storage system of claim 4, wherein, The number of the plurality of fans is the same as the number of the plurality of battery modules, and one fan is used to adjust the gas flow speed around a corresponding battery module.

13. The energy storage system of claim 12, wherein, The controller comprises a first control unit and a plurality of second control units. The number of the plurality of second control units is the same as the number of the plurality of fans. One second control unit is used to control the working state of a corresponding fan. The first control unit is used to control the working state of the plurality of air conditioners.

14. The energy storage system of claim 13, wherein, One second control unit is also used to detect the temperature of a corresponding battery module and send the temperature detection result of the battery module to the first control unit.

15. The energy storage system of claim 8, wherein, The energy storage system further comprises a first temperature sensor. The first temperature sensor is arranged outside the energy storage container. The first temperature sensor is used to detect the temperature outside the energy storage container and send the detection result to the controller.

16. A temperature control method for an energy storage system, characterized by, The energy storage system comprises at least one energy storage container, each of which comprises a temperature control system and a battery cluster, the battery cluster comprises a plurality of battery modules connected in series, each of which comprises a plurality of batteries, the temperature control system is used to adjust the temperature in the energy storage container, and the temperature control method comprises: Using the correspondence between the available capacity of the battery cluster and the plurality of different set temperatures of the temperature control system and the correspondence between the power consumption of the temperature control system and the plurality of different set temperatures of the temperature control system, the set temperature of the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximum is determined as the target temperature; when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximum, it indicates that the ratio of the power consumption of the temperature control system to the available capacity of the battery cluster is minimum; Adjusting the temperature in the energy storage container to the target temperature.

17. The temperature control method of claim 16, wherein, Before the correspondence between the available capacity of the battery cluster and the set temperature of the temperature control system and the correspondence between the power consumption of the temperature control system and the set temperature of the temperature control system are used to determine the set temperature of the temperature control system when the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is maximum as the target temperature, the method further comprises: The correspondence between the available capacity of the battery cluster and the set temperature of the temperature control system corresponding to different working states of the battery cluster is pre-calibrated and stored.

18. The temperature control method of claim 16, wherein, Before the target temperature is determined as the set temperature of the temperature control system at which the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is the largest, the method further comprises: determining the correspondence between the available capacity of the battery cluster and a plurality of different set temperatures in the set temperature collection of the temperature control system at the current charging rate when the battery cluster is in the charging state; determining the correspondence between the available capacity of the battery cluster and a plurality of different set temperatures in the set temperature collection of the temperature control system at the current discharging rate when the battery cluster is in the discharging state; determining the correspondence between the available capacity of the battery cluster and a plurality of different set temperatures in the set temperature collection of the temperature control system at the current state of charge when the battery cluster is in the silent state.

19. The temperature control method according to any one of claims 16-18, characterized by, The temperature control system comprises a plurality of air conditioners and a plurality of fans, and before the target temperature is determined as the set temperature of the temperature control system at which the difference between the available capacity of the battery cluster and the power consumption of the temperature control system is the largest, the method further comprises: determining the correspondence between the total power consumption of the started air conditioners and a plurality of different set temperatures in the set temperature collection of the temperature control system, and determining the total power consumption of the started fans; determining the correspondence between the power consumption of the temperature control system and a plurality of different set temperatures in the set temperature collection of the temperature control system according to the correspondence between the total power consumption of the started air conditioners and a plurality of different set temperatures in the set temperature collection of the temperature control system, and the total power consumption of the started fans.

20. The temperature control method of claim 19, wherein, All the plurality of fans are started, and the total power consumption of the started fans specifically comprises: determining the rotation speed of the plurality of fans according to the temperatures of the plurality of battery modules; determining the total power consumption of the plurality of fans according to the total number of the plurality of fans and the rotation speed of the plurality of fans.

21. The temperature control method of claim 19, wherein, The total power consumption of the started fans specifically comprises: determining the number of started fans and the rotation speed of the started fans according to the temperatures of the plurality of battery modules; determining the total power consumption of the started fans according to the number of started fans and the rotation speed of the started fans.

22. The temperature control method of claim 19, wherein, The correspondence between the total power consumption of the started air conditioners and a plurality of different set temperatures in the set temperature collection of the temperature control system specifically comprises: determining the correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set temperature collection of the temperature control system; determining a correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set of set temperatures of the temperature control system; determining a correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set of set temperatures of the temperature control system according to the correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set of set temperatures of the temperature control system, and the correspondence between the refrigerating capacity of a single air conditioner and a plurality of different set temperatures in the set of set temperatures of the temperature control system, and the correspondence between the number of air conditioners turned on and a plurality of different set temperatures in the set of set temperatures of the temperature control system; determining a correspondence between the total power consumption of the turned-on air conditioners and a plurality of different set temperatures in the set of set temperatures of the temperature control system according to the correspondence between the number of air conditioners turned on and a plurality of different set temperatures in the set of set temperatures of the temperature control system, and the correspondence between the power consumption of a single air conditioner and a plurality of different set temperatures in the set of set temperatures of the temperature control system.

23. The temperature control method of claim 22, wherein, determining a correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set of set temperatures of the temperature control system, specifically comprising: determining heat transferred from the solar radiation to the energy storage container by using the solar radiation intensity and the outer surface area of the energy storage container; determining a correspondence between heat transferred from the outside of the energy storage container to the inside of the energy storage container by heat conduction and a plurality of different set temperatures in the set of set temperatures of the temperature control system by using the heat transfer coefficient of the energy storage container, the outer surface area of the energy storage container, and the current temperature outside the energy storage container; determining heat generated by the plurality of battery modules when working by using the working time of the plurality of battery modules, the working current of the plurality of battery modules, the internal resistance of the plurality of battery modules, and the open circuit voltage of the plurality of battery modules; determining a correspondence between the total refrigerating capacity required by the energy storage container and a plurality of different set temperatures in the set of set temperatures of the temperature control system by using the heat transferred from the solar radiation to the energy storage container, the correspondence between heat transferred from the outside of the energy storage container to the inside of the energy storage container by heat conduction and a plurality of different set temperatures in the set of set temperatures of the temperature control system, and the heat generated by the plurality of battery modules when working.

24. The temperature control method of claim 23, wherein, Before the step of determining heat generated by the plurality of battery modules when working by using the working time of the plurality of battery modules, the working current of the plurality of battery modules, the internal resistance of the plurality of battery modules, and the open circuit voltage of the plurality of battery modules, the method further comprises: determining the working time of the plurality of battery modules and the working current of the plurality of battery modules according to the received operation information.

25. The temperature control method of claim 22, wherein, Before determining the correspondence between the total power consumption of the opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the correspondence between the number of opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system, and the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system, the method further comprises: pre-calibrating and storing the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to different temperatures outside the energy storage container; determining the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to the current temperature outside the energy storage container.

26. The temperature control method of claim 22, wherein, Before determining the correspondence between the total power consumption of the opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system according to the correspondence between the number of opened air conditioners and the plurality of different set temperatures in the set temperature collection of the temperature control system, and the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system, the method further comprises: pre-calibrating and storing the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to different temperatures outside the energy storage container; determining the correspondence between the power consumption of a single air conditioner and the plurality of different set temperatures in the set temperature collection of the temperature control system corresponding to the current temperature outside the energy storage container.

27. A photovoltaic power system, characterized by The photovoltaic power generation system comprises the energy storage system according to any one of claims 1-15, and further comprises a photovoltaic inverter, an alternating current bus and a plurality of photovoltaic components; The plurality of photovoltaic components are connected to the input end of the photovoltaic inverter; The output end of the photovoltaic inverter is connected to the alternating current bus; The alternating current bus is connected to the energy storage system and an alternating current grid; The photovoltaic component is configured to generate direct current by using light energy, and transmit the direct current to the photovoltaic inverter; The photovoltaic inverter is configured to convert the direct current into alternating current, and provide the alternating current to the alternating current grid through the alternating current bus, and / or charge the energy storage system.

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