Control method, controller and energy storage system applied to energy storage system

Abstract

The application discloses a control method, a controller and an energy storage system applied to the energy storage system. The method comprises the following steps: when the temperature of a battery is greater than or equal to a low-temperature charging allowable threshold and less than a battery temperature at which a charging SOP is equal to a rated value, the following steps are performed: when the charging SOP of the battery is greater than or equal to a rated power of a heating assembly, the heating assembly is controlled to be turned on or turned off according to an actual charging power of the battery, an actual power of the heating assembly and the charging SOP; when the charging SOP is less than the rated power of the heating assembly, the heating assembly is controlled to be turned on or turned off according to an SOC of the battery and a number of times of heating of the heating assembly; and when the heating assembly is turned on, the heating assembly is controlled to be turned on or turned off according to a requested power and an actual input power of an energy storage converter. In the above manner, the heating of the battery at a low temperature can be realized, the charging SOP is increased, the performance of the battery is improved, and therefore the energy utilization efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of control technology for energy storage systems, and particularly to a control method, controller, and energy storage system applied to energy storage systems. Background Technology

[0002] Lithium-ion batteries, with their advantages of high energy density, long cycle life, and no memory effect, have become the mainstream power source for photovoltaic energy storage systems, electric vehicles, and portable electronic devices. However, the electrochemical performance of lithium-ion batteries is highly sensitive to ambient temperature, especially in low-temperature environments (usually below 10°C, particularly below 0°C), where their performance deteriorates significantly, severely restricting the all-weather application and economic benefits of energy storage systems in cold regions.

[0003] Low temperatures severely limit the battery's state of power (SOP), directly leading to a decline in battery performance and consequently a reduction in energy utilization efficiency. Summary of the Invention

[0004] This application provides a control method, controller, and energy storage system for use in energy storage systems. These methods enable heating of batteries at low temperatures to increase the starting point of charging (SOP), thereby improving battery performance and energy utilization efficiency.

[0005] In a first aspect, embodiments of this application provide a control method for an energy storage system. The energy storage system includes a battery and an energy storage converter. The battery includes a cell module and a heating component, with the heating component electrically connected to both the cell module and the energy storage converter. The cell module includes at least one cell. The method includes the following steps when the battery temperature is greater than or equal to a first preset temperature threshold and less than a second preset temperature threshold: when the battery's charging SOP is greater than or equal to the rated power of the heating component, controlling the heating component to turn on or off based on the battery's actual charging power, the heating component's actual power, and the charging SOP; when the charging SOP is less than the heating component's rated power, controlling the heating component to turn on or off based on the battery's SOC and the number of times the heating component has been used; and when the heating component is on, controlling the heating component to turn on or off based on the requested power and the actual input power of the energy storage converter. The first preset temperature threshold is a low-temperature charging allowable threshold, and the second preset temperature threshold is the battery temperature when the charging SOP equals the rated value.

[0006] In one or more embodiments, controlling the heating component to turn on or off based on the battery's actual charging power, the heating component's actual power, and the charging start point (SOP) includes: determining the battery's actual input power based on the battery's actual charging power when the heating component is off, or the sum of the battery's actual charging power and the heating component's actual power when the heating component is on; determining the requested power based on the charging SOP when the heating component is off, or the sum of the charging SOP and the heating component's actual power when the heating component is on; calculating the ratio of the battery's actual input power to the requested power; turning on the heating component when the ratio is greater than a first preset ratio threshold, and turning off the heating component when the ratio is less than or equal to a second preset ratio threshold.

[0007] In one or more embodiments, controlling the heating component to turn on or off based on the battery's SOC and the number of times the heating component has been heated includes: when the following conditions one and two are met, controlling the heating component to turn on based on the sum of the charging SOP and the rated power of the heating component as the requested power, and incrementing the number of times the heating component has been heated by one; wherein, condition one: the product of the battery's SOC and its rated capacity is greater than the energy of a single heating by the heating component; condition two: the battery's SOC is greater than a first preset SOC threshold, or, the battery's SOC is less than or equal to the first preset SOC threshold and the number of times the heating component has been heated is less than or equal to a first preset number of times threshold.

[0008] In one or more embodiments, controlling the heating component to turn on or off based on the battery's SOC and the number of times the heating component has been heated includes: controlling the heating component to remain off when the battery's SOC is less than or equal to a first preset SOC threshold and the number of times the heating component has been heated is greater than a first preset number threshold.

[0009] In one or more embodiments, when the heating component is turned on, controlling the heating component to turn on or off based on the requested power and the actual input power of the energy storage converter includes: when the heating component is turned on, performing the following steps: if the actual input power of the energy storage converter increases with the increase of the requested power, and the battery remains in a charging state, then the heating component remains in the on state until the charging SOP is greater than or equal to the rated power of the heating component, and then returning to the step of controlling the heating component to turn on or off based on the actual charging power of the battery, the actual power of the heating component, and the charging SOP when the charging SOP of the battery is greater than or equal to the rated power of the heating component, and subsequent steps thereof; if the actual input power of the energy storage converter does not increase with the increase of the requested power, and the battery is in a discharge process, then the heating component is controlled to turn off, and after a first delay, returning to the step of controlling the heating component to turn on or off based on the battery SOC and the number of times the heating component has been heated when the charging SOP is less than the rated power of the heating component, and subsequent steps thereof.

[0010] In one or more embodiments, the method further includes: resetting the number of times the heating component is heated when one of the following conditions three and four is met; wherein, condition three: the SOC of the battery is greater than a second preset SOC threshold; condition four: no voltage signal and current signal of the power supply of the energy storage converter are collected within a second time period, and no power output of the power supply is detected, and at the same time it is determined that the energy storage system performs a shutdown operation.

[0011] In one or more embodiments, the method further includes: when the temperature of the battery is less than a first preset temperature threshold and the SOC of the battery is equal to 0, performing the following steps: disconnecting the charging and discharging circuit of the battery to control the battery to stop outputting or inputting power; controlling the energy storage converter to output power to the heating component to turn on the heating component.

[0012] In one or more embodiments, the method further includes: when the temperature of the battery is less than a first preset temperature threshold and the SOC of the battery is greater than 0, performing the following steps: turning on the charging and discharging circuit of the battery; controlling the output power of the battery and the energy storage converter to the heating component to turn on the heating component, wherein the power output by the energy storage converter is less than the actual power of the heating component.

[0013] In one or more embodiments, after controlling the battery and energy storage converter to output power to the heating component to turn on the heating component, the method further includes: determining the remaining SOC of the battery after the heating component has finished heating, based on the current SOC of the battery and the energy required for the heating component to heat up; disconnecting the battery's charging and discharging circuit when the remaining SOC is less than a third preset SOC threshold, and controlling the energy storage converter to output power to the heating component to turn on the heating component; and maintaining the current state unchanged when the remaining SOC remains greater than or equal to the third preset SOC threshold, until the battery temperature increases to a first preset temperature threshold.

[0014] In one or more embodiments, determining the remaining SOC of the battery after the heating component has finished heating, based on the current SOC of the battery and the energy required for heating by the heating component, includes: determining the energy required for heating by the heating component based on the product of the actual heating power of the heating component, the preset heating time, and the heating efficiency; determining the rated total energy of the battery based on the product of the rated capacity and the nominal voltage of the battery; determining the SOC consumed by the heating component for heating based on the ratio of the energy required for heating by the heating component to the rated total energy of the battery; and determining the remaining SOC of the battery after the heating component has finished heating based on the difference between the current SOC of the battery and the SOC consumed by the heating component.

[0015] Secondly, embodiments of this application provide a controller, including: at least one processor and a memory; the memory is coupled to the processor and is used to store instructions or programs, which, when executed by the at least one processor, cause the at least one processor to perform the control method applied to the energy storage system as described in the first aspect.

[0016] Thirdly, embodiments of this application provide an energy storage system, including: a power supply; an energy storage converter electrically connected to the power supply; a battery including a cell module and a heating component, the heating component being electrically connected to the cell module and the energy storage converter respectively, wherein the cell module includes at least one cell; and a controller as described in the second aspect, the controller being electrically connected to the battery and the energy storage converter respectively.

[0017] The beneficial effects of this application are as follows: The control method applied to an energy storage system in this application includes the following steps when the battery temperature is greater than or equal to a first preset temperature threshold and less than a second preset temperature threshold: when the battery's charging SOP is greater than or equal to the rated power of the heating component, the heating component is controlled to turn on or off based on the actual charging power of the battery, the actual power of the heating component, and the charging SOP; when the charging SOP is less than the rated power of the heating component, the following steps are performed: the heating component is controlled to turn on or off based on the battery's SOC and the number of times the heating component has been heated; when the heating component is on, the heating component is controlled to turn on or off based on the requested power and the actual input power of the energy storage converter; wherein, the first preset temperature threshold is a low-temperature charging allowable threshold, and the second preset temperature threshold is the battery temperature when the charging SOP is equal to the rated value. Thus, when low temperature limits the battery's charging SOP, the battery temperature, charging SOP, and battery SOC parameters can be combined to achieve heating of the battery at low temperatures, thereby increasing the charging SOP, improving battery performance, and thus improving energy utilization efficiency. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0019] Figure 1 This is a schematic diagram of the energy storage system provided in the embodiments of this application. Figure 1 ;

[0020] Figure 2 This is a schematic diagram of the energy storage system provided in the embodiments of this application. Figure 2 ;

[0021] Figure 3 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 1 ;

[0022] Figure 4 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 2 ;

[0023] Figure 5 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 3 ;

[0024] Figure 6 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 4 ;

[0025] Figure 7 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 5 ;

[0026] Figure 8 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 6 ;

[0027] Figure 9 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 7 ;

[0028] Figure 10 This is a flowchart of a control method for energy storage systems provided in the embodiments of this application. Figure 8 . Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described clearly and in detail below with reference to the accompanying drawings. Obviously, the embodiments in this application are only some embodiments, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0030] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0031] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0032] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the composition of an energy storage system provided in an embodiment of this application. Figure 1 As shown, the energy storage system 100 includes a battery 110, an energy storage converter 120, a controller 130, and a power supply 140.

[0033] Battery 110 includes a cell module 111 and a heating assembly 112. The cell module 111 includes at least one cell; when the cell module 111 includes multiple cells, the cells are connected in parallel, series, or a combination thereof, with the latter including both series and parallel connections. The cell module 111 is used to store and provide electrical energy. The heating assembly 112 is electrically connected to both the cell module 111 and the energy storage converter 120. The cell module 111 can supply power to the heating assembly 112. The heating assembly 112 refers to a collection of devices integrated within the battery module or battery pack for providing heat to the cell module 111 in low-temperature environments to raise its temperature. The material of the heating assembly 112 can be a composite material of metal, metal alloy, graphite, carbon, conductive ceramic, or other ceramic and metallic materials with appropriate resistance. Suitable metallic or alloy materials include at least one of nickel, cobalt, zirconium, titanium, nickel alloys, cobalt alloys, zirconium alloys, titanium alloys, nickel-chromium alloys, nickel-iron alloys, iron-chromium alloys, iron-chromium-aluminum alloys, iron-manganese-aluminum based alloys, or stainless steel.

[0034] The Power Conversion System (PCS) 120, also known as a bidirectional energy storage inverter, is a reversible power electronic conversion device that connects the battery 110 to the power supply 140, or the battery 110 to a load. The PCS 120 enables bidirectional conversion between DC and AC power, performs maximum power point tracking (MPPT) for photovoltaics, and provides functions such as battery charge / discharge management, grid-connected / off-grid power supply, and system safety protection. The power supply 140 can charge the battery module 111 and supply power to the heating assembly 112 via the PCS 120. In some embodiments, the power supply 140 includes photovoltaic modules and / or the power grid. A photovoltaic module, also known as a solar panel, refers to a small, independently usable power generation device formed by connecting multiple photovoltaic cells in series or parallel and undergoing rigorous encapsulation processes to create specific voltage and current output characteristics, capable of stable operation in harsh outdoor environments for extended periods.

[0035] The controller 130 can be a microcontroller unit (MCU) or a digital signal processing (DSP) controller, etc.

[0036] The controller 130 includes at least one processor 131 and a memory 132. The memory 132 may be built into the controller 130 or external to the controller 130. The memory 132 may also be a remotely configured memory connected to the controller 130 via a network.

[0037] Memory 132, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory 132 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal, etc. Furthermore, memory 132 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 132 may optionally include memory remotely located relative to processor 131, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0038] The processor 131 performs various functions of the terminal and processes data by running or executing software programs and / or modules stored in the memory 132 and calling data stored in the memory 132, thereby performing overall monitoring of the terminal, such as implementing the control method for energy storage systems described in any embodiment of this application.

[0039] Processor 131 can be one or more. Figure 1 The example provided uses a processor 131. Processor 131 and memory 132 can be connected via a bus or other means. Processor 131 may include a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field-programmable gate array (FPGA) device, etc. Processor 131 can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0040] It should be noted that, as Figure 1 The hardware structure of the energy storage system 100 shown is only an example, and the energy storage system 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application-specific integrated circuits.

[0041] For example, such as Figure 2As shown, the energy storage system 100 also includes a main switch 113 and a heating switch 114. The main switch 113 is electrically connected to the battery cell module 111. When the main switch 113 is closed, the charging and discharging circuit of the battery 110 is open, allowing the battery 110 to charge or discharge, which in turn allows the battery cell module 111 to charge or discharge. When the main switch 113 is open, the charging and discharging circuit of the battery 110 is closed, preventing the battery 110 from charging or discharging, which in turn prevents the battery cell module 111 from charging or discharging. The heating switch 114 is electrically connected to the heating component 112. When the heating switch 114 is closed, the heating component 112 is energized and heats up; when the heating switch 114 is open, the heating component 112 is de-energized.

[0042] Please refer to Figure 3 , Figure 3 A flowchart illustrating a control method applied to an energy storage system according to an embodiment of this application. The energy storage system includes a battery and an energy storage inverter. The battery includes a cell module and a heating assembly, with the heating assembly electrically connected to both the cell module and the energy storage inverter. Each cell module includes at least one cell. In some embodiments, the energy storage system can be controlled via... Figures 1-2 The circuit structure shown is implemented in detail in the above embodiments, and will not be repeated here.

[0043] like Figure 3 As shown, the control method applied to the energy storage system first determines the relationship between the battery temperature and a first preset temperature threshold and a second preset temperature threshold. The first preset temperature threshold is the low-temperature charging allowable threshold, which refers to the lowest temperature at which the Battery Management System (BMS) determines that external current must flow into the battery. That is, the battery is only allowed to be charged when its temperature is greater than or equal to the low-temperature charging allowable threshold. The second preset temperature threshold is the battery temperature at which the charging SOP equals the rated value. Specifically, the second preset temperature threshold refers to the lowest battery temperature at which the battery's internal electrochemical reaction kinetics (mainly the migration rate of lithium ions in the electrolyte and the insertion rate on the negative electrode surface) have fully recovered under the current state, allowing the charging SOP calculated by the BMS to reach the rated charging power specified on the battery nameplate. Here, the battery's charging SOP refers to the maximum power that the BMS allows the battery to input.

[0044] When the battery temperature is greater than or equal to a first preset temperature threshold and less than a second preset temperature threshold, it can be determined that the low temperature limits the battery's charging SOP, preventing it from reaching the rated value, which leads to a reduction in the battery's allowable input power. In this case, the relationship between the battery's charging SOP and the rated power of the heating component is first determined.

[0045] When the battery charging SOP is greater than or equal to the rated power of the heating component, perform the following step S310.

[0046] Step S310: Control the heating component to turn on or off based on the actual charging power of the battery, the actual power of the heating component, and the charging SOP.

[0047] Specifically, if the battery's charging SOP is greater than or equal to the heating element's rated power, it means the battery's allowed input power is greater than the power the heating element needs to consume; that is, the battery's "receiving capacity" is stronger than the heating element's "consuming capacity." Based on this, step S310 needs to be further executed to determine whether, in actual application scenarios, the power supply's output power can truly be used to both charge the battery and power the heating element for heating. This is because the power supply's output power is unstable. For example, when the power supply includes photovoltaic modules, unpredictable weather conditions can cause fluctuations in the photovoltaic module's output power (e.g., a sudden cloud cover on a sunny day with good sunlight can cause a sharp drop in the photovoltaic module's output power). Therefore, based on the aforementioned theoretical basis, step S310 needs to be executed in conjunction with the actual situation to accurately determine whether the heating element can be controlled to turn on.

[0048] In some embodiments, such as Figure 4 As shown, the specific implementation process of step S310 includes the following steps S410 to S440.

[0049] Step S410: Determine the actual input power of the battery based on the actual charging power of the battery when the heating component is not turned on, or the sum of the actual charging power of the battery and the actual power of the heating component when the heating component is turned on.

[0050] Step S420: Determine the requested power based on the charging SOP when the heating component is not turned on, or the sum of the charging SOP when the heating component is turned on and the actual power of the heating component.

[0051] Step S430: Calculate the ratio of the battery's actual input power to the requested power.

[0052] Specifically, when the heating component is not turned on, the actual input power of the battery (i.e. the actual output power of the energy storage converter) is the actual charging power of the battery (also the actual charging power of the cell module in the battery), and the requested power is the charging SOP. Therefore, based on the ratio, it can be determined whether the output of the power supply can keep up with the battery's receiving capacity in a pure charging scenario.

[0053] When the heating element is turned on, the actual input power of the battery is the sum of the actual charging power of the battery and the actual power of the heating element, and the requested power is the sum of the charging start point (SOP) and the actual power of the heating element. Therefore, based on the ratio, it can be determined whether the output of the power supply can meet the total demand of both in the scenario of charging and heating in parallel.

[0054] Step S440: Turn on the heating component when the ratio is greater than the first preset ratio threshold, and turn off the heating component when the ratio is less than or equal to the second preset ratio threshold.

[0055] Specifically, a ratio greater than a first preset ratio threshold indicates that the power supply has surplus energy and the energy storage converter has not encountered an input bottleneck (i.e., MPPT is not limited). In this case, if heating is not currently in progress, the heating component is activated; if heating has already occurred, the heating component remains activated, thus utilizing energy and improving battery performance. The first preset ratio threshold is a pre-set threshold that can be set based on the actual application scenario. For example, in a specific embodiment, the first preset ratio threshold is set to any value in [0.9, 1).

[0056] If the ratio is less than or equal to the second preset ratio threshold, it means that the output of the power supply (and the input of the photovoltaic modules when the power supply includes photovoltaic modules) has reached its limit, and the energy storage converter cannot fill the requested power gap. In this case, if heating is currently in progress, the heating component is turned off; if heating is not in progress, the heating component is prohibited from being turned on, thereby prioritizing the charging of the battery cell modules. The first preset ratio threshold is a preset threshold that can be set based on the actual application scenario. For example, in a specific embodiment, the second preset ratio threshold is set to any value in [0.8, 0.9).

[0057] Of course, when the ratio is greater than the second preset ratio threshold and less than or equal to the first preset ratio threshold, the state of the previous moment is maintained to prevent oscillation.

[0058] In this way, the potential of the power supply can be maximized without sacrificing system stability (preventing overload shutdown), achieving a dynamic optimal balance between battery "heating" and "energy storage" in low-temperature environments.

[0059] When the charging SOP is less than the rated power of the heating component, perform steps S320 to S330 as follows.

[0060] Specifically, a charging SOP less than the rated power of the heating element means that the battery's allowed input power is less than the power required by the heating element, indicating that the battery's "receiving capacity" is weak and cannot meet the heating element's "consumption." When the power supply includes photovoltaic modules, a charging SOP less than the rated power of the heating element is common in scenarios where the photovoltaic modules' energy is insufficient, such as at sunrise (when sunlight is just beginning), sunset, or on cloudy or rainy / snowy days when photovoltaic energy is weak. Based on this, it is necessary to attempt to start the heating element for heating based on parameters such as the battery's SOC, charging SOP, and the heating power of the heating element. The specific implementation process is steps S320 and S330.

[0061] Step S320: Control the heating component to turn on or off based on the battery's SOC and the number of times the heating component is heated.

[0062] Specifically, step S320 implements the principle that the heating component is only turned on for heating when the battery's SOC and the number of heating cycles meet preset conditions. This achieves a differentiated testing mechanism that combines the battery's SOC (State of Charge) and the number of heating cycles, thereby coupling energy and temperature. This avoids both the risk of battery depletion due to excessive heating attempts at low SOC and the energy waste caused by limiting heating attempts at high SOC.

[0063] In some embodiments, such as Figure 5 As shown, the specific implementation process of step S320 includes the following steps: First, determine whether the product of the battery's SOC and rated capacity is greater than the energy of a single heating cycle by the heating component, to ensure that the battery's current remaining usable energy (wherein, the product of the battery's SOC and rated capacity is the battery's current remaining usable energy) is strictly greater than the total energy consumed in performing a complete heating attempt, thereby avoiding a power depletion crisis caused by blind heating. The energy of a single heating cycle by the heating component is the product of the heating component's power and the heating duration. The heating duration is determined by the actual application scenario; for example, in a specific embodiment, the heating duration is determined based on the response time of the energy storage converter.

[0064] After determining that the battery's SOC is greater than the energy of a single heating cycle of the heating component, it is necessary to further determine whether the battery's SOC is greater than the first preset SOC threshold in order to determine whether the battery currently has a large amount of energy redundancy.

[0065] When the battery's SOC is determined to be greater than the first preset SOC threshold, it can be determined that the battery has a large remaining charge, and attempting heating will not lead to a risk of depletion. Therefore, there is no need to limit the number of heating attempts. Based on this, the subsequent step S510 can be executed directly. The first preset SOC threshold is a pre-set threshold that can be set based on the actual application scenario. For example, in a specific embodiment, the first preset SOC threshold is configured as any value within [15%, 25%].

[0066] When the battery's SOC is determined to be less than or equal to a first preset SOC threshold, it can be determined that the battery's remaining power is low, and the number of heating attempts needs to be strictly limited. This means it is necessary to further determine whether the number of heating attempts by the heating component is less than or equal to the first preset threshold to prevent the risk of battery depletion due to excessive heating attempts. When the number of heating attempts by the heating component is less than or equal to the first preset threshold, subsequent step S510 can be executed. The first preset threshold is a pre-set threshold that can be set based on the actual application scenario. For example, in a specific embodiment, the first preset threshold is configured as any value in [2, 5].

[0067] Step S510: Based on the sum of the charging SOP and the rated power of the heating component as the requested power, control the heating component to turn on and increment the number of times the heating component heats.

[0068] Specifically, the sum of the charging SOP and the rated power of the heating component is used as the requested power to power the energy storage converter, simultaneously energizing the battery's input or output power, and activating the heating component for heating. At this point, it can be determined that one heating attempt has been made, and the heating count needs to be incremented by one.

[0069] In some embodiments, the specific implementation process of step S320 further includes the following steps: when the SOC of the battery is less than or equal to a first preset SOC threshold and the number of times the heating component is heated is greater than a first preset number threshold, the heating component is controlled to remain off.

[0070] Specifically, this step may include two scenarios: (1) Initially, the battery's SOC is greater than a first preset SOC threshold. After one or more heating cycles, the battery's SOC decreases to less than or equal to the first preset SOC threshold. Understandably, in this case, the number of heating cycles begins to be calculated from when the battery's SOC is greater than the first preset SOC threshold; (2) Initially, the battery's SOC is less than or equal to the first preset SOC threshold. For scenarios (1) and (2), as long as the number of heating cycles detected by the heating component exceeds the first preset number of cycles threshold, the heating component is controlled to remain off and no further heating attempts are made to avoid the risk of power depletion caused by excessive heating attempts at low SOC.

[0071] Step S330: When the heating component is turned on, control the heating component to turn on or off according to the requested power and the actual input power of the energy storage converter.

[0072] The requested power refers to the total power demand that the system reports to its superior (i.e., the energy storage converter), which is the ideal power value that the system expects to obtain. According to step S510, the requested power is the sum of the charging SOP and the rated power of the heating components.

[0073] The actual input power of the energy storage converter is the real-time active power at the AC input terminal of the energy storage converter, which represents the upper limit of the actual energy that the current system can provide to the battery terminal (including charging and heating).

[0074] After the heating component is turned on, by monitoring the requested power and the actual input power of the energy storage converter in real time, it is possible to determine whether the actual input power of the energy storage converter can simultaneously meet the needs of charging and heating in practical application scenarios, so as to accurately determine whether to keep the heating component on.

[0075] In some embodiments, such as Figure 6 As shown, the specific implementation process of step S330 includes the following steps: when the heating component is turned on, the following steps S610 to S620 are executed.

[0076] Step S610: If the actual input power of the energy storage converter increases with the increase of the requested power, and the battery remains in the charging state, then keep the heating component in the on state until the charging SOP is greater than or equal to the rated power of the heating component. Then return to the execution of the step of controlling the heating component to turn on or off according to the actual charging power of the battery, the actual power of the heating component, and the charging SOP when the charging SOP of the battery is greater than or equal to the rated power of the heating component, and the subsequent steps.

[0077] Specifically, on the one hand, the actual input power of the energy storage converter can increase linearly in sync with the requested power, indicating that the current power supply has additional output capacity and has not reached its limit; on the other hand, the battery is in a continuous charging state, meaning there is no battery discharge output. Thus, it can be determined that the power supply has expansion potential (i.e., the current charging power has not reached the physical limit of the power supply, and there is a power margin). In this case, since the heating element is already on, it is only necessary to keep the heating element on, which is beneficial to maximizing energy utilization efficiency. Simultaneously, increasing the charging start-up pressure (SOP) improves battery performance (i.e., the allowed charging and discharging power of the battery increases), thereby improving energy utilization efficiency.

[0078] Subsequently, as the heating component heats up, the charging SOP gradually increases until the charging SOP is greater than or equal to the rated power of the heating component, and then the process returns to step S310 and subsequent steps.

[0079] Step S620: If the actual input power of the energy storage converter does not increase with the increase of the requested power, and the battery is discharging, then control the heating component to turn off, and after a first delay, return to execute the step of controlling the heating component to turn on or off according to the battery's SOC and the number of times the heating component has been heated when the charging SOP is less than the rated power of the heating component, and the subsequent steps.

[0080] Specifically, on the one hand, the system requested more power (including charging and heating), but the power supply could not provide it, and the actual power was "clamped" at a certain upper limit, unable to increase synchronously with the requested power. On the other hand, battery discharge was detected, meaning that because the external input power was insufficient to meet the total demand, the energy gap was forced to be filled by the battery itself through discharge. Thus, it can be determined that the power supply has no redundancy and cannot meet the dual demand of "charging + heating". At the same time, the heating attempt failed, meaning that the previous strategy of trying to use redundant power for heating was ineffective, and continuing to maintain heating would lead to system instability. In this case, the heating component should be immediately shut down, and only the charging operation should be maintained, that is, all available external input power should be used to charge the battery, stopping the passive discharge behavior of the battery and restoring the normal unidirectional charging state.

[0081] Furthermore, after the heating component is turned off, a first delay is performed, during which parameters such as the charging SOP and battery SOC are continuously monitored. At the end of the first delay, if the charging SOP is again less than the rated power of the heating component, step S320 and subsequent steps are executed again. This achieves the process of continuously retrying heating when the conditions are met. The first delay is a preset duration that can be set based on the actual application scenario. For example, in a specific embodiment, when the power supply includes photovoltaic modules, the first delay can be set according to the local latitude and sunrise conditions. For instance, near the equator, the photovoltaic intensity typically reaches 25% 30 minutes after sunrise, so the first delay can be set to 30 minutes; while in high-latitude regions, the photovoltaic intensity only reaches 10% 30 minutes after sunrise, so the first delay can be set to greater than 30 minutes.

[0082] This application embodiment also provides two cases for resetting the number of heating cycles of the heating component, as follows:

[0083] (1) The SOC of the battery is greater than the second preset SOC threshold.

[0084] The second preset SOC threshold is greater than the first preset SOC threshold. A battery SOC greater than the second preset SOC threshold indicates sufficient battery power. With the energy storage system active, the heating component's heating count is reset to zero, facilitating future heating attempts. For example, when the power supply includes photovoltaic modules, if sunlight disappears at night and the battery is fully charged, the heating component's heating count can be reset to zero, allowing for heating attempts the following day when sunlight returns.

[0085] (2) If the voltage and current signals of the power supply of the energy storage converter are not collected within the second time period, and the power supply is found to have no power output, the energy storage system is determined to perform a shutdown operation.

[0086] The second duration is a pre-set duration that can be adjusted based on the actual application scenario. If no voltage or current signals are collected from the power supply of the energy storage converter within the second duration, and no power output is detected, it means the power supply has disappeared; simultaneously, the energy storage system has been shut down. In this case, the heating component's heating count is reset to zero, allowing for a re-attempt to be made when the energy storage system is restarted. For example, when the power supply includes photovoltaic modules, after the energy storage system is shut down on a given day, resetting the heating component's heating count allows for a re-attempt to be made the following day when the energy storage system is restarted and sunlight returns.

[0087] The foregoing described the specific implementation process when the battery temperature is greater than or equal to a first preset temperature threshold. Furthermore, this application also provides a specific implementation process when the battery temperature is less than the first preset temperature threshold, including two cases: a battery SOC equal to 0 and a SOC greater than 0, which will be described separately below.

[0088] Figure 7 The specific implementation process is shown when the battery temperature is below a first preset temperature threshold and the battery's SOC is equal to 0. For example... Figure 7 As shown, when the battery temperature is less than the first preset temperature threshold and the battery SOC is equal to 0, the following steps S710 to S720 are executed.

[0089] Step S710: Disconnect the battery's charging and discharging circuit to control the battery to stop outputting or inputting power.

[0090] Step S720: Control the energy storage converter to output power to the heating component to turn on the heating component.

[0091] Specifically, if the battery temperature is below a first preset temperature threshold, it means the battery is not allowed to be charged. Similarly, if the battery's SOC is 0, it should not be discharged to prevent over-discharge and damage. Therefore, the battery's output circuit is first disconnected to prevent damage from over-discharge at low temperatures or from lithium plating caused by attempted charging. Next, the energy storage converter directly directs the power supply to the heating element to activate it and heat the battery. When the energy storage system... Figure 2 As shown, disconnecting the battery's charging and discharging circuit corresponds to disconnecting the main switch 113.

[0092] In one specific embodiment, when the power supply includes photovoltaic modules, a power adaptive matching process is further implemented during the process of using the energy storage converter to output power to the heating module to turn it on. Specifically, this is achieved by utilizing the purely resistive characteristics of the heating module (P=U). 2 The energy storage inverter, acting as the control core, collects the voltage and current of the photovoltaic side in real time. When there is sufficient sunlight, the energy storage inverter adjusts the output voltage to the rated voltage of the heating module, enabling the heating power of the heating module to reach its maximum value (i.e., rated power) and achieve rapid heating. When there is insufficient sunlight, the inverter executes maximum power point tracking (MPPT) or power limiting mode, dynamically reducing the output voltage to the maximum power that the photovoltaic module can provide, ensuring that "only the amount of electricity is used as much as the amount of light is available," maintaining uninterrupted heating, and thus maximizing energy utilization.

[0093] Figure 8 The specific implementation process is shown when the battery temperature is below a first preset temperature threshold and the battery's SOC is greater than 0. For example... Figure 8 As shown, when the battery temperature is less than the first preset temperature threshold and the battery SOC is greater than 0, the following steps S810 to S820 are executed.

[0094] Step S810: Turn on the battery's charging and discharging circuit.

[0095] Step S820: Control the output power of the battery and energy storage converter to the heating component to turn on the heating component, wherein the power output of the energy storage converter is less than the actual power of the heating component.

[0096] Specifically, if the battery temperature is below a first preset temperature threshold, it means the battery is not allowed to be charged. However, if the battery's SOC is greater than 0, it can discharge. Based on this, the battery output circuit and the heating component circuit can be closed simultaneously. At this time, the battery and the output of the energy storage converter are connected in parallel, jointly supplying power to the heating component. Simultaneously, the power output of the energy storage converter is controlled to be less than the actual power of the heating component to ensure the battery can discharge (thus avoiding charging). Specifically, most of the heating power is provided by the energy storage converter, and the battery only needs to provide a very small difference in power to maintain a weak discharge state. In this way, the main heating task can be completed using the energy from the power supply, while the small discharge of the battery maintains the circuit voltage stability and assists in heating until the battery temperature reaches the low-temperature charging threshold.

[0097] Among them, when energy storage systems are like Figure 2 As shown, the main switch 113 is turned on when the charging and discharging circuit of the battery is activated. Furthermore, the heating switch 114 is also turned on when controlling the output power of the battery and energy storage converter to the heating assembly.

[0098] In some embodiments, such as Figure 9 As shown, after performing step S820, the control method applied to the energy storage system further includes the following steps S910 to S920.

[0099] Step S910: Determine the remaining SOC of the battery after the heating component has finished heating, based on the current SOC of the battery and the energy required for heating by the heating component.

[0100] By predicting the remaining SOC of the battery, it is possible to prevent the battery from being depleted before its temperature reaches a first preset temperature threshold.

[0101] In some embodiments, such as Figure 10 As shown, the specific implementation process of step S910 includes the following steps S1010 to S1040.

[0102] Step S1010: Determine the energy required for heating the heating component based on the product of the actual heating power of the heating component, the preset heating time, and the heating efficiency.

[0103] Step S1020: Determine the rated total energy of the battery based on the product of the battery's rated capacity and its nominal voltage.

[0104] Step S1030: Determine the SOC consumed by the heating component for heating based on the ratio of the energy required for heating by the heating component to the rated total energy of the battery.

[0105] Step S1040: Determine the remaining SOC of the battery after the heating component has finished heating, based on the difference between the current SOC of the battery and the SOC consumed by the heating component.

[0106] Specifically, the energy E required for the heating component to heat up heat For: E heat =P heat ×t heat ×k, where P heat t represents the actual heating power of the heating element. heat The preset heating time is given by k, and the heating efficiency is given by E. The rated total energy of the battery is E. bat For: E bat =C rated ×U nom , where C rated U is the rated capacity of the battery. nom This is the nominal voltage of the battery. The SOC consumed by the heating element is: SOC=E heat / E bat ,in, SOC refers to the SOC consumed by the heating element. Therefore, the remaining SOC is: SOC rem =SOC cur - SOC, where SOC cur The current SOC of the battery. rem The remaining SOC.

[0107] Step S920: When the remaining SOC is less than the third preset SOC threshold, disconnect the battery's charging and discharging circuit, and control the energy storage converter to output power to the heating component to turn on the heating component.

[0108] Step S930: When the remaining SOC remains greater than or equal to the third preset SOC threshold, maintain the current state until the battery temperature increases to the first preset temperature threshold.

[0109] The third preset SOC threshold refers to the minimum remaining SOC that must be maintained when the battery finishes heating up and reaches a rechargeable state (in the rechargeable state, the battery temperature is greater than or equal to the first preset temperature threshold). The third preset SOC threshold can be set according to the actual application scenario. For example, in a specific embodiment, the third preset SOC threshold is set to 0 to ensure that the remaining SOC is ≥ 0, which helps to prevent the battery from being depleted before its temperature reaches the first preset temperature threshold.

[0110] If the power supply weakens, for example, if the power supply includes photovoltaic modules, reduced sunlight can cause the photovoltaic modules to lose energy, potentially leading to the remaining State of Charge (SOC) falling below the third preset SOC threshold. In this case, the battery's charging and discharging circuit needs to be disconnected promptly, and the energy storage converter's output power should be controlled to supply power to the heating module to keep it on. At this time, the heating power is entirely borne by the power supply. Although the heating speed may slow down due to the reduced power, this ensures that the battery's SOC does not decrease further, preventing damage from over-discharge.

[0111] If the remaining SOC remains greater than or equal to the third preset SOC threshold, it is determined that the battery has sufficient energy. Therefore, the current state remains unchanged, i.e., the implementation processes of steps S810 and S820 remain unchanged, and the heating component continues to be kept in a heating state to heat the battery until the battery temperature is heated to equal the first preset temperature threshold. At this point, the process returns to the execution of the relevant content executed when the battery temperature is greater than or equal to the first preset temperature threshold and less than the second preset temperature threshold (i.e., steps S310, S320, and subsequent content).

[0112] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0113] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control method applied to an energy storage system, characterized in that, The energy storage system includes a battery and an energy storage converter. The battery includes a cell module and a heating assembly. The heating assembly is electrically connected to both the cell module and the energy storage converter. The cell module includes at least one cell. The method includes: When the temperature of the battery is greater than or equal to a first preset temperature threshold and less than a second preset temperature threshold, the following steps are performed: When the charging SOP of the battery is greater than or equal to the rated power of the heating component, the heating component is controlled to be turned on or off according to the actual charging power of the battery, the actual power of the heating component, and the charging SOP. When the charging SOP is less than the rated power of the heating component, the heating component is controlled to turn on or off according to the SOC of the battery and the number of times the heating component is heated. When the heating component is turned on, the heating component is controlled to turn on or off according to the requested power and the actual input power of the energy storage converter; The first preset temperature threshold is the low-temperature charging allowable threshold, and the second preset temperature threshold is the battery temperature when the charging SOP is equal to the rated value.

2. The method according to claim 1, characterized in that, The step of controlling the heating component to turn on or off based on the actual charging power of the battery, the actual power of the heating component, and the charging SOP includes: The actual input power of the battery is determined based on the actual charging power of the battery when the heating component is not turned on, or the sum of the actual charging power of the battery and the actual power of the heating component when the heating component is turned on. The requested power is determined based on the charging SOP when the heating component is not turned on, or the sum of the charging SOP and the actual power of the heating component when the heating component is turned on. Calculate the ratio of the actual input power of the battery to the requested power; The heating component is turned on when the ratio is greater than a first preset ratio threshold, and turned off when the ratio is less than or equal to a second preset ratio threshold.

3. The method according to claim 1, characterized in that, The step of controlling the heating component to turn on or off based on the battery's SOC and the number of times the heating component has been heated includes: When conditions one and two are met, the heating component is controlled to turn on based on the sum of the charging SOP and the rated power of the heating component as the requested power, and the number of times the heating component heats is incremented by one. Among them, condition one: the product of the battery's SOC and rated capacity is greater than the energy of a single heating cycle of the heating component; Condition 2: The SOC of the battery is greater than the first preset SOC threshold, or the SOC of the battery is less than or equal to the first preset SOC threshold and the number of times the heating component heats is less than or equal to the first preset number of times threshold.

4. The method according to claim 3, characterized in that, The step of controlling the heating component to turn on or off based on the battery's SOC and the number of times the heating component has been heated includes: When the SOC of the battery is less than or equal to the first preset SOC threshold and the number of times the heating component heats is greater than the first preset number of times threshold, the heating component is controlled to remain off.

5. The method according to claim 1, characterized in that, The step of controlling the heating component to turn on or off based on the requested power and the actual input power of the energy storage converter when the heating component is turned on includes: When the heating component is turned on, the following steps are performed: If the actual input power of the energy storage converter increases with the increase of the requested power, and the battery remains in a charging state, then the heating component remains in the on state until the charging SOP is greater than or equal to the rated power of the heating component. Then, return to the execution of the step of controlling the heating component to turn on or off according to the actual charging power of the battery, the actual power of the heating component, and the charging SOP when the charging SOP of the battery is greater than or equal to the rated power of the heating component, and the subsequent steps. If the actual input power of the energy storage converter does not increase with the increase of the requested power, and the battery is discharging, then the heating component is controlled to turn off, and after a first delay, the process returns to the step of controlling the heating component to turn on or off according to the battery's SOC and the number of times the heating component has been heated when the charging SOP is less than the rated power of the heating component, and the subsequent steps.

6. The method according to claim 1, characterized in that, The method further includes: The number of times the heating component has been heated is reset to zero when one of the following conditions three and four is met; Among them, condition 3: the SOC of the battery is greater than the second preset SOC threshold; Condition 4: If no voltage or current signal of the power supply of the energy storage converter is collected within the second time period, and no power output of the power supply is detected, the energy storage system is determined to perform a shutdown operation.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: When the battery temperature is lower than the first preset temperature threshold and the battery's SOC is equal to 0, the following steps are performed: Disconnect the charging and discharging circuit of the battery to control the battery to stop outputting or inputting power; The energy storage converter outputs power to the heating component to turn on the heating component.

8. The method according to any one of claims 1-6, characterized in that, The method further includes: When the battery temperature is lower than the first preset temperature threshold and the battery SOC is greater than 0, the following steps are performed: To connect the charging and discharging circuit of the battery; The power output of the battery and the energy storage converter is controlled to the heating component to turn on the heating component, wherein the power output of the energy storage converter is less than the actual power of the heating component.

9. The method according to claim 8, characterized in that, After controlling the battery and the energy storage converter to output power to the heating assembly to turn on the heating assembly, the method further includes: Based on the current SOC of the battery and the energy required for heating by the heating component, determine the remaining SOC of the battery after the heating component has finished heating; When the remaining SOC is less than the third preset SOC threshold, the charging and discharging circuit of the battery is disconnected, and the energy storage converter is controlled to output power to the heating component to turn on the heating component; While the remaining SOC remains greater than or equal to the third preset SOC threshold, the current state remains unchanged until the battery temperature increases to the first preset temperature threshold.

10. The method according to claim 9, characterized in that, Determining the remaining SOC of the battery after the heating component has finished heating, based on the battery's current SOC and the energy required for heating by the heating component, includes: The energy required for heating the heating component is determined by multiplying the actual heating power of the heating component, the preset heating time, and the heating efficiency. The rated total energy of the battery is determined by multiplying its rated capacity and its nominal voltage. The SOC consumed by the heating component for heating is determined based on the ratio of the energy required for heating by the heating component to the rated total energy of the battery. The remaining SOC of the battery is determined based on the difference between the current SOC of the battery and the SOC consumed by the heating component.

11. A controller, characterized in that, include: At least one processor and memory; The memory is coupled to the processor and is used to store instructions or programs that, when executed by the at least one processor, cause the at least one processor to perform the control method applied to the energy storage system as described in any one of claims 1-10.

12. An energy storage system, characterized in that, include: Power supply; The energy storage converter is electrically connected to the power supply. A battery includes a cell module and a heating assembly, wherein the heating assembly is electrically connected to the cell module and the energy storage converter, and the cell module includes at least one cell. And the controller as described in claim 11, wherein the controller is electrically connected to the battery and the energy storage converter, respectively.

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