Battery module and replacement control method thereof, photoelectric energy storage system and electrical equipment

Abstract

The invention provides a battery module and a replacement control method thereof, a photoelectric energy storage system and electrical equipment, and relates to the technical field of photoelectric energy storage, the battery module is internally provided with an energy storage battery and a battery switch module, and the state of each battery switch in the battery switch module is controlled through the battery switch module according to a switch control signal, so that the energy storage battery is replaced. The method comprises the following steps: adding a battery module into a circuit system, so that an energy storage battery in the battery module accesses the circuit system according to a circuit access mode corresponding to the battery module, and determining a battery switch state based on the state of each battery switch in the newly added battery module, so as to transfer electric energy according to an electric energy conversion mode corresponding to the battery switch state of the newly added battery module. The voltage of all battery modules in the system tends to be consistent, the voltage of new and old modules does not need to be adjusted to be consistent through manual operation before the capacitor module is replaced or expanded, and therefore the problems that in the prior art, the module replacement and expansion process is complex, and the time cost is high due to the fact that the voltage of the new and old modules needs to be adjusted to be consistent through manual operation are solved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic energy storage technology, and in particular to a battery module and its replacement control method, a photovoltaic energy storage system, and electrical equipment. Background Technology

[0002] Driven by the demand for green and low-carbon energy structure transformation, stacked residential photovoltaic and energy storage integrated units, which combine photovoltaics and energy storage, have become key equipment for promoting energy transformation because they can achieve energy transfer through intelligent control.

[0003] However, in practical applications of stacked residential photovoltaic-energy storage systems, battery module replacement or capacity expansion is frequently required due to factors such as battery aging or upgraded user power demands. Currently, to avoid reduced system charging and discharging efficiency caused by voltage inconsistencies between the newly added and old modules, the main approach is to adjust the voltage of the original energy storage system modules to match the voltage of the new modules before battery module replacement or capacity expansion, or to adjust the voltage of the new modules to match the voltage of the original energy storage system modules. However, this module replacement control method involves complex installation steps, requires a significant amount of time, and increases time costs and after-sales pressure. Summary of the Invention

[0004] This application provides a battery module and its replacement control method, a photovoltaic energy storage system, and electrical equipment to reduce the difficulty of battery module replacement and capacity expansion, thereby solving the problem of high time cost in the prior art for replacing battery modules.

[0005] In a first aspect, this application provides a battery module, including: an energy storage battery and a battery switch module; The battery switch module includes at least five battery switches and is configured to control the state of each battery switch in the battery switch module according to the switch control signal, so that the energy storage battery is connected to the circuit system according to the circuit connection method corresponding to the battery module. The at least five battery switches include a first switch, a second switch, a third switch, a fourth switch, and a fifth switch; The positive terminal of the energy storage battery is electrically connected to the first terminal of the first switch and the first terminal of the fourth switch, respectively, and the negative terminal of the energy storage battery is electrically connected to the first terminal of the third switch and the first terminal of the fifth switch, respectively. The second terminal of the first switch is electrically connected to the first terminal of the second switch to serve as the first positive terminal of the battery module; The second terminal of the fourth switch serves as the second positive terminal of the battery module; the second terminal of the second switch is electrically connected to the second terminal of the third switch to serve as the first negative terminal of the battery module. The second terminal of the five switches serves as the second negative terminal of the battery module.

[0006] Optionally, the second switch is a normally closed switch; The first switch, the third switch, the fourth switch, and the fifth switch are all normally open switches.

[0007] Secondly, this application provides a method for controlling the replacement of a battery module, including: When adding a battery module to a photovoltaic energy storage system, determine the voltage of the original module and the voltage of the new module; Based on the original module voltage and the new module voltage, and combined with the load power and photovoltaic power of the photovoltaic energy storage system, the circuit access method corresponding to the newly added battery module is determined; According to the circuit connection method, a switch control signal is output, which is used to control the state of each battery switch in the newly added battery module. Based on the power conversion method corresponding to the battery switch state of the newly added battery module, power is transferred to make the voltage of all battery modules in the photovoltaic energy storage system tend to be consistent. When the voltages of all battery modules become consistent, the battery switch state is set to a preset target switch state.

[0008] Optionally, determining the circuit connection method of the newly added battery module based on the original module voltage and the new module voltage, combined with the load power and photovoltaic power of the photovoltaic energy storage system, includes: The voltage of the original module is compared with the voltage of the new module to obtain the voltage comparison result; Using the voltage comparison results, the energy conversion method corresponding to the newly added battery module is determined; Based on the aforementioned power conversion method, the circuit connection method of the newly added battery module is determined by comparing the load power with the photovoltaic power.

[0009] Optionally, determining the circuit connection method of the new battery module based on the comparison result between the load power and the photovoltaic power, according to the power conversion method, includes: The energy storage module status is determined by comparing the load power with the photovoltaic power. When the energy storage module is in the working state, the circuit connection method of the newly added battery module is determined by the power conversion method.

[0010] Optionally, all battery modules in the photovoltaic energy storage system include the newly added battery module and the original energy storage module. The energy transfer based on the energy conversion method corresponding to the battery switching state of the newly added battery module, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent, includes: When the power conversion method is a discharge conversion method, the transfer output power corresponding to the newly added battery module is determined for the discharge conversion method; According to the transferred output power, the power output of the newly added battery module is controlled so that the voltage of the newly added battery module is reduced to be consistent with the voltage of the original energy storage module.

[0011] Optionally, all battery modules in the photovoltaic energy storage system include the newly added battery module and the original energy storage module. The energy transfer based on the energy conversion method corresponding to the battery switching state of the newly added battery module, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent, includes: When the power conversion method is a charging conversion method, the target transfer power corresponding to the new battery module is determined based on the comparison result between the load power and the photovoltaic power for the charging conversion method. According to the target transfer power, the original energy storage module is controlled to replenish the new battery module, so that the voltage of the new battery module rises to be consistent with the voltage of the original energy storage module.

[0012] Thirdly, this application provides a photovoltaic energy storage system, the photovoltaic energy storage system comprising a module replacement control device and various battery modules electrically connected to the module replacement control device, the battery modules being the battery modules as described in any one of the first aspects above, and the module replacement control device being configured to implement the battery module replacement control method as described in any one of the second aspects above.

[0013] Optionally, the photovoltaic energy storage system further includes: a photovoltaic panel, a bidirectional DC-DC converter, a photovoltaic DC-DC converter, and a grid AC-DC converter; Wherein, the first terminal of the bidirectional DC-DC converter is electrically connected to the second positive terminal of the battery module, the second terminal of the bidirectional DC-DC converter is electrically connected to the first negative terminal of the battery module, the third terminal of the bidirectional DC-DC converter is electrically connected to the second negative terminal of the battery module, the fourth terminal of the bidirectional DC-DC converter is electrically connected to the first positive terminal of the battery module, and the DC terminal of the bidirectional DC-DC converter is electrically connected to the output terminal of the photovoltaic DC-DC converter and the DC terminal of the grid AC-DC converter, respectively. The input terminal of the photovoltaic DC-DC converter is electrically connected to the output terminal of the photovoltaic panel.

[0014] Fourthly, this application provides an electrical device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory is used to store computer programs; and the processor is used to execute the program stored in the memory to implement the steps of the battery module replacement control method as described in any of the second aspects above.

[0015] The technical solution provided in this application embodiment includes an energy storage battery and a battery switch module in the battery module. The battery switch module contains at least five battery switches and is configured to control the state of each battery switch in the battery switch module according to a switch control signal, so that the energy storage battery is connected to the circuit system according to the circuit access method corresponding to the battery module. This allows the battery module to be directly connected to the photovoltaic energy storage system. Subsequently, the battery switch state of the new battery module can be determined based on the state of each battery switch in the new battery module, and energy transfer can be performed according to the energy conversion method corresponding to the battery switch state of the new battery module. This makes the voltage of all battery modules in the photovoltaic energy storage system tend to be consistent, eliminating the need for manual operation to adjust the voltage of the old and new modules to be consistent before replacing or expanding the capacitor module. This reduces the difficulty of battery module replacement and expansion, simplifies the battery module installation steps, and reduces the installation time cost of the battery module. It solves the problems of complex module replacement and expansion processes and high time costs caused by the need for manual operation to adjust the voltage of the old and new modules to be consistent in the prior art. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of the circuit structure of a battery module provided in an embodiment of this application; Figure 2A flowchart illustrating the steps of a battery module replacement control method provided in this application embodiment; Figure 3 A schematic diagram of a photovoltaic energy storage system is provided as an example in this application; Figure 4 A schematic diagram of the structure of a photovoltaic energy storage system after the addition of a battery module is provided as an example of this application; Figure 5 A schematic diagram illustrating the series connection of a newly added battery module with other battery modules in the system, as provided in this application example; Figure 6 This application provides a schematic diagram illustrating the connection of a new battery module to a system via circuit power supply. Figure 7 A structural block diagram of a photoelectric energy storage system provided in this application embodiment; Figure 8 A schematic diagram of the structure of a bidirectional DC-DC converter is provided as an example of this application; Figure 9 This is a schematic diagram of the structure of an electrical device provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0022] Promoting the construction of a green, low-carbon, and circular development system hinges on energy structure transformation. For example, stacked residential photovoltaic-storage integrated systems, which combine photovoltaic power generation and energy storage technologies, can achieve efficient energy transfer through intelligent control, coordinating the operation of photovoltaic modules and energy storage batteries, thereby accelerating the transformation of the social energy structure. However, during the use of stacked residential photovoltaic-storage integrated systems, battery replacement and capacity expansion may be necessary due to natural battery aging or increased user demand requiring expanded energy storage capacity.

[0023] To address the issue of low charging and discharging efficiency caused by voltage inconsistencies between the new and old battery modules after replacement or capacity expansion in existing technologies, this application provides a new battery module and its replacement control method. This method allows for direct replacement or capacity expansion of the new battery module even when the voltages of the new and old modules are inconsistent, without affecting the charging and discharging efficiency after replacement or capacity expansion. This reduces the difficulty of battery module replacement and capacity expansion in stacked photovoltaic-storage integrated machines, simplifies installation steps, and reduces time costs.

[0024] In this context, "new module" can refer to a newly added battery module, while "old module" can refer to the existing battery module before replacement or capacity expansion. A battery module, also known as an energy storage module, is specifically used to store electrical energy and can power other circuit devices based on the stored energy. For example, it can power various circuit devices and their connected loads in a photovoltaic energy storage system. This application does not limit this specific use.

[0025] A photovoltaic energy storage system refers to a system that can utilize photovoltaic power generation and battery module energy storage. For example, a photovoltaic energy storage system can be a stacked residential photovoltaic-energy storage integrated system. Specifically, the stacked residential photovoltaic-energy storage integrated system can be composed of energy storage modules, energy storage DC-DC converters, photovoltaic DC-DC converters, and grid AC-DC converters. This application example does not limit this.

[0026] In specific implementations, the energy storage module in a photovoltaic energy storage system may include one or more battery modules. For example, the energy storage module in a stacked residential photovoltaic energy storage system may include a first battery module and a second battery module connected in series, so that the first battery module and the second battery module connected in series serve as the energy storage module in the stacked residential photovoltaic energy storage system. This allows the stacked residential photovoltaic energy storage system to store electrical energy through the energy storage module and to power other circuit devices based on the stored electrical energy. The embodiments of this application do not impose specific limitations on the number of battery modules provided in the energy storage module.

[0027] In one exemplary embodiment, such as Figure 1 As shown, the battery module provided in this embodiment includes an energy storage battery 110 and a battery switch module 120. The battery switch module 120 includes at least five battery switches to control the circuit operation mode of the energy storage battery 110 after it is connected to the system. This allows the battery module provided in this embodiment to be directly connected to the photovoltaic energy storage system as a new battery module. Furthermore, by detecting the voltage of the original module and the voltage of the new module, combined with the load power and photovoltaic power of the photovoltaic energy storage system, the circuit connection mode of the battery module can be determined. Based on the circuit connection mode, the state of each battery switch in the new battery module is controlled by switch control signals. The state of each battery switch in the group determines the battery switch state of the newly added battery module. Then, according to the power conversion method corresponding to the battery switch state of the newly added battery module, power transfer is carried out to make the voltage of all battery modules in the photovoltaic energy storage system tend to be consistent. When the voltage of all modules in the photovoltaic energy storage system tends to be consistent, the battery switch state of the newly added battery module is switched to the preset target switch state corresponding to the newly added battery module. Based on the target switch state, the addition of the new battery module is completed. There is no need to manually adjust the voltage of the old and new modules to be consistent before replacing or expanding the capacitor module. This solves the problems of complex module replacement and expansion processes and high time costs caused by the need for manual adjustment of the voltage of the old and new modules to be consistent in the existing technology.

[0028] The switch control signal refers to the control signal generated according to the circuit connection method corresponding to the battery module. Specifically, it can be used to control the state of each battery switch in the battery switch module 120 so that the energy storage battery 110 is connected to the circuit system according to the circuit connection method. The circuit system can refer to the system to which the battery module is currently connected, such as a photovoltaic energy storage system. This application embodiment does not limit this.

[0029] The battery switch module 120 is configured to control the state of each battery switch in the battery switch module 120 according to the switch control signal, so that the energy storage battery 110 is connected to the circuit system according to the circuit access method corresponding to the battery module, so that the battery module can transfer energy according to the energy conversion method corresponding to the battery switch state, realize the automatic energy conversion of the battery module, and make the voltage of the battery module tend to be consistent with the voltage of other battery modules in the circuit system.

[0030] In this embodiment, the battery switch module 120 includes at least five battery switches: a first switch K2, a second switch K3, a third switch K4, a fourth switch K5, and a fifth switch K6. The positive terminal of the energy storage battery 110 is electrically connected to the first terminal of the first switch K2 and the first terminal of the fourth switch K5, respectively. The negative terminal of the energy storage battery 110 is electrically connected to the first terminal of the third switch K4 and the first terminal of the fifth switch K6, respectively. The second terminal of the first switch K2 is electrically connected to the first terminal of the second switch K3, serving as the first positive terminal of the battery module. For example, the first positive terminal of the battery module can serve as the positive terminal of the battery module, used to connect other battery modules, such as connecting to the negative terminal of other battery modules, to achieve electrical connection between battery modules through series connection. The second terminal of the fourth switch K5 serves as the second positive terminal of the battery module, used to connect to the first terminal of the bidirectional DC-DC converter of the photovoltaic energy storage system, for subsequent... Energy transfer can be achieved through a bidirectional DC-DC converter. The second terminal of the second switch K3 is electrically connected to the second terminal of the third switch K4 to serve as the first negative terminal of the battery module. For example, the first negative terminal of the battery module can serve as the negative terminal of the battery module and be connected to the second terminal of the bidirectional DC-DC converter of the photovoltaic energy storage system so that energy transfer can be achieved through the bidirectional DC-DC converter. The second terminal of the five switches serves as the second negative terminal of the battery module and is connected to the third terminal of the bidirectional DC-DC converter. This allows the battery switch module 120 to control the energy storage battery 110 in the battery module to be connected to the photovoltaic energy storage system according to the circuit connection method corresponding to the battery module, based on the switch control signal. This allows the battery module to transfer energy according to the energy conversion method corresponding to the battery switch state, thereby making the voltage of the battery module more consistent with the voltage of other battery modules in the photovoltaic energy storage system, thus ensuring that the photovoltaic energy storage system can work normally. The fourth terminal of the bidirectional DC-DC converter is used to connect to the positive terminal of the battery in the photovoltaic energy storage system. For example, the bidirectional DC-DC converter can be used as an energy storage DC / DC converter that is electrically connected to the energy storage module in the system, so that the system can realize the charging and discharging of the battery of the energy storage module through the bidirectional DC-DC converter.

[0031] In some optional embodiments of this application, a normally closed switch can be used as the second switch K3 in the battery switch module 120, and a normally open switch can be used to implement the switching functions of the first switch K2, the third switch K4, the fourth switch K5, and the fifth switch K6 in the battery switch module 120. This allows the energy storage battery 110 to be connected to the circuit system via a bypass circuit through the normally closed switch when the battery module is connected, ensuring the safety of the battery module's connection to the circuit system. Optionally, in the embodiments of this application, the second switch K3 is a normally closed switch; the first switch K2, the third switch K4, the fourth switch K5, and the fifth switch K6 are all normally open switches.

[0032] To enable direct replacement or capacity expansion of battery modules even when the voltages of old and new modules are inconsistent, embodiments of this application also provide a battery module replacement control method, such as... Figure 2 As shown, the battery module replacement control method provided in this application embodiment may specifically include the following steps: Step 210: When adding a battery module to the photovoltaic energy storage system, determine the voltage of the original module and the voltage of the new module; The original module voltage characterizes the voltage of the original energy storage module in the system before the addition of the new battery module. The original energy storage module can refer to the existing battery module in the system. The new module voltage characterizes the voltage of the newly added battery module. For example, if the original energy storage module in the photovoltaic energy storage system contains two battery modules connected in series before the addition of the new battery module, then the original module voltage can refer to the voltage of the two battery modules connected in series in the system. That is, the original module voltage refers to the module voltage of the energy storage in the first battery module and the second battery module connected in series. After the third battery module is connected to the photovoltaic energy storage system as a new battery module, the voltage of the third battery module can be determined as the voltage of the new battery module.

[0033] Step 220: Based on the original module voltage and the new module voltage, and in combination with the load power and photovoltaic power of the photovoltaic energy storage system, determine the circuit access method corresponding to the newly added battery module; Among them, the load power of the photovoltaic energy storage system can refer to the power required to output when the photovoltaic energy storage system is connected to an external load. In specific implementation, the load power is less than or equal to the rated maximum output power of the photovoltaic energy storage system. The photovoltaic power can refer to the power output by the photovoltaic panel under the current light intensity. Specifically, it can be determined according to the photovoltaic optimization algorithm. The photovoltaic power can be used to characterize the power output of the photovoltaic panel under the current light intensity.

[0034] In this step, the embodiments of this application can determine the power conversion method corresponding to the new battery module by judging the magnitude of the original module voltage and the new module voltage. Based on the comparison result between the original module voltage and the new module voltage, the power conversion method corresponding to the new battery module can be determined. Then, based on the power conversion method and the comparison result between the load power and the photovoltaic power, the circuit access method corresponding to the new battery module can be determined. This allows the generation of a switch control signal corresponding to the new battery module based on the circuit access method. Furthermore, the state of each battery switch in the battery switch module can be controlled by the switch control signal to ensure that the energy storage battery in the new battery module is connected to the photovoltaic energy storage system according to the circuit access method corresponding to the new battery module, thus ensuring that the photovoltaic energy storage system can work normally.

[0035] Step 230: According to the circuit connection method, output a switch control signal. The switch control signal is used to control the state of each battery switch in the newly added battery module. In this step, the embodiments of this application can output a switch control signal corresponding to the circuit access method to the battery switch module of the newly added battery module. This switch control signal controls the state of each battery switch in the newly added battery module, allowing the newly added battery module to be connected to the photovoltaic energy storage system according to the aforementioned circuit access method, ensuring the normal operation of the photovoltaic energy storage system. Specifically, the battery switch module of the newly added battery module can be used to control the state of each battery switch in the newly added battery module based on the switch control signal, so that the energy storage batteries in the newly added battery module are connected to the photovoltaic energy storage system according to the circuit access method corresponding to the newly added battery module, ensuring the normal operation of the photovoltaic energy storage system.

[0036] Step 240: Based on the power conversion method corresponding to the battery switch state of the newly added battery module, power transfer is performed to make the voltage of all battery modules in the photovoltaic energy storage system tend to be consistent. The battery switch status of the newly added battery module can be used to characterize the status of each battery switch in the newly added battery module. Specifically, it can include the status of each battery switch in the newly added battery module. This application embodiment does not limit this.

[0037] Specifically, in this application embodiment, the battery switch state of the newly added battery module can be determined based on the state of each battery switch in the newly added battery module, so as to determine the power conversion method corresponding to the newly added battery module according to the battery switch state, and then the power can be transferred according to the power conversion method, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent.

[0038] Step 250: When the voltages of all battery modules in the photovoltaic energy storage system tend to be consistent, the battery switch state is set to a preset target switch state.

[0039] The preset target switch state refers to the preset switch state set for the battery module. Specifically, it can be used to complete the addition of a new battery module, so that the new battery module can be connected to other battery modules in the photovoltaic energy storage system according to the battery module connection method. For example, when the battery module connection method is a series connection method, the target switch state can be used to enable the new battery module to be connected in series with other battery modules in the photovoltaic energy storage system to automatically complete the addition of the new battery module without the need for manual adjustment of the module voltage. This can reduce the difficulty of battery module replacement and capacity expansion, simplify the installation steps, and reduce the installation time cost of the battery module.

[0040] In summary, this application embodiment, when adding a battery module to a photovoltaic energy storage system, determines the voltage of the original module and the voltage of the new module. Based on these voltages, and considering the load power and photovoltaic power of the photovoltaic energy storage system, it determines the circuit connection method corresponding to the new battery module. Subsequently, according to the circuit connection method, it outputs a switch control signal to control the state of each battery switch in the new battery module. This allows for energy transfer based on the energy conversion method corresponding to the battery switch states of the new battery module, making the voltages of all battery modules in the photovoltaic energy storage system more consistent. When the voltages of all battery modules in the photovoltaic energy storage system are consistent, the battery switch states are set to a preset target switch state. This allows for the automatic addition of the new battery module based on the target switch state, eliminating the need for manual adjustment of the module voltage. This reduces the difficulty of battery module replacement and capacity expansion, simplifying battery module installation steps and reducing installation time costs.

[0041] In one optional embodiment of this application, after determining the original module voltage and the new module voltage, the power conversion method corresponding to the new battery module can be determined based on the voltage comparison result between the original module voltage and the new module voltage. Then, based on the power conversion method, the circuit connection method of the new battery module is determined using the comparison result between the load power and the photovoltaic power. Optionally, determining the circuit connection method of the new battery module based on the original module voltage and the new module voltage, combined with the load power and photovoltaic power of the photovoltaic energy storage system, may specifically include: comparing the original module voltage and the new module voltage to obtain a voltage comparison result; using the voltage comparison result to determine the power conversion method corresponding to the new battery module; and based on the power conversion method, using the comparison result between the load power and the photovoltaic power to determine the circuit connection method of the new battery module.

[0042] In this embodiment, different voltage comparison results can correspond to different energy conversion methods. Furthermore, this embodiment can categorize the energy conversion methods corresponding to the newly added battery module into charging conversion methods and discharging conversion methods based on the battery's operating mode. For example, when the battery operating modes are divided into battery charging mode and battery discharging mode, if the voltage of the original module is greater than the voltage of the new module, the charging conversion method can be determined based on the battery charging mode to be the corresponding energy conversion method for the new battery module. This allows the new battery module to be charged based on the voltage difference between the original and new module voltages, gradually increasing the voltage of the new module and automatically adjusting the voltages of the old and new modules to be the same. If the voltage of the original module is less than the voltage of the new module, the discharging conversion method can be determined based on the battery discharging mode to be the corresponding energy conversion method for the new battery module. This allows the energy stored in the new battery module to be transferred based on the voltage difference between the original and new module voltages, gradually decreasing the voltage of the new module until it drops to the same level as the original module voltage, at which point the energy transfer stops, thus automatically adjusting the voltages of the old and new modules.

[0043] Optionally, in this embodiment of the application, the voltage comparison result is used to determine the power conversion method corresponding to the newly added battery module. Specifically, this may include: when the voltage comparison result is a first voltage comparison result, determining the preset charging conversion method corresponding to the first voltage comparison result as the power conversion method corresponding to the newly added battery module; or, when the voltage comparison result is a second voltage comparison result, determining the preset discharging conversion method corresponding to the second voltage comparison result as the power conversion method corresponding to the newly added battery module.

[0044] Specifically, when the voltage of the original module is greater than the voltage of the new module, this application can generate a first voltage comparison result, and determine the preset charging conversion method corresponding to the first voltage comparison result as the power conversion method corresponding to the new battery module based on the first voltage comparison result. When the voltage of the original module is less than the voltage of the new module, a second voltage comparison result can be generated, and determine the preset discharging conversion method corresponding to the second voltage comparison result as the power conversion method corresponding to the new battery module based on the second voltage comparison result. When the voltage of the original module is equal to the voltage of the new module, it can be determined that no power transfer is needed at present, and a voltage equality comparison result can be generated so that step 250 can be directly executed based on the voltage equality comparison result to set the battery switch state of the new battery module to a preset target switch state, so as to complete the addition of the new battery module based on the target switch state.

[0045] Furthermore, considering that the load power of the photovoltaic energy storage system is provided by the photovoltaic panels and / or the energy storage modules in the system, that is, the load power of the photovoltaic energy storage system is usually greater than or equal to the photovoltaic power, in an optional embodiment of this application, the state of the energy storage module can be determined by judging whether the load power is greater than the photovoltaic power, so as to determine the circuit access method of the new battery module based on the state of the energy storage module and the power conversion method corresponding to the new battery module.

[0046] The energy storage module status in a photovoltaic energy storage system refers to the state of the energy storage module within the system, specifically divided into operating state and standby state. The operating state indicates that the energy storage module has entered a working state, while the standby state indicates that it is in a standby state. Optionally, in this embodiment, the energy storage module status can be determined by comparing the load power and photovoltaic power. Based on this comparison, the circuit connection method for the newly added battery module can be determined.

[0047] For example, when the load power is greater than the photovoltaic power, the energy storage module needs to be put into operation to meet the load's working requirements. At this time, the working state of the energy storage module can be determined as the energy storage module state. Subsequently, the circuit connection method of the new battery module can be determined based on the working state of the energy storage module and the power conversion method corresponding to the new battery module. When the load power is not greater than the photovoltaic power, such as when the load power is equal to the photovoltaic power, the energy storage module is in standby mode. The standby mode of the energy storage module can then be determined as the energy storage module state. Based on the standby mode of the energy storage module, the power conversion method corresponding to the new battery module, and the comparison result between the load power and the photovoltaic power, the circuit connection method of the new battery module can be determined.

[0048] Optionally, in this embodiment of the application, the method of determining the circuit access method of the new battery module based on the power conversion method and the comparison result between the load power and the photovoltaic power may specifically include: determining the energy storage module status by using the comparison result between the load power and the photovoltaic power; and determining the circuit access method of the new battery module by using the power conversion method when the energy storage module status is the energy storage module working status.

[0049] For example, when the energy storage module is in the working state, it can be determined whether the power conversion method is a charging conversion method. If the power conversion method is a charging conversion method, the circuit bypass access method can be determined as the circuit access method for the new battery module. If the power conversion method is a discharging conversion method, the circuit power supply access method can be determined as the circuit access method for the new battery module, so that the state of each battery switch in the new battery module can be controlled according to the circuit power supply access method.

[0050] In an optional embodiment of this application, when the energy storage module is in the working state, the circuit access method of the new battery module is determined by the power conversion method. Specifically, this may include: when the energy storage module is in the working state, determining whether the power conversion method is a charging conversion method; if the power conversion method is a charging conversion method, then determining the circuit bypass access method as the circuit access method of the new battery module, so that the state of each battery switch in the new battery module can be controlled according to the circuit bypass access method, so that the new battery module is in a bypass state, thereby avoiding the problem of low voltage protection of the energy storage system caused by excessive voltage difference between the original module and the new module, which would affect the user experience.

[0051] In another optional embodiment of this application, when the energy storage module is in an operating state, the circuit connection method of the new battery module is determined using the power conversion method. Specifically, this may include: when the energy storage module is in an operating state, determining whether the power conversion method is a discharge conversion method; if the power conversion method is a discharge conversion method, determining the circuit power supply connection method as the circuit connection method for the new battery module. If the power conversion method is not a discharge conversion method, it can be determined as a charging conversion method, so that if the power conversion method is a charging conversion method, the circuit bypass connection method is determined as the circuit connection method for the new battery module, thus changing the discharge conversion method.

[0052] For example, when the energy storage module is in the working state, that is, when the load power is greater than the photovoltaic power, it can first be determined whether the power conversion method is a charging conversion method. If the power conversion method corresponding to the new battery module is not a charging conversion method, then it can be determined whether the power conversion method is a discharging conversion method to determine the circuit access method of the new battery module.

[0053] For example, when the energy storage module is in the working state, that is, when the load power is greater than the photovoltaic power, it can first be determined whether the power conversion method is a discharge conversion method. If the power conversion method corresponding to the new battery module is not a discharge conversion method, then it can be determined whether the power conversion method is a charging conversion method to determine the circuit access method of the new battery module.

[0054] Specifically, if the power conversion method corresponding to the newly added battery module is not a charging conversion method, but a discharging conversion method, then the circuit power supply access method can be determined as the circuit access method of the newly added battery module. This allows the state of each battery switch in the newly added battery module to be controlled according to the circuit power supply access method, so that the newly added battery module is in a power supply working state. Based on this power supply working state, the output power of the newly added battery module can be transferred to supply power to the system load, so that the voltage of the new module gradually decreases until the voltage of the new module decreases to the same level as the voltage of the original module. At this point, the battery switch state is set to the preset target switch state, thereby achieving the purpose of automatically adjusting the voltage of the old and new modules.

[0055] Optionally, in this embodiment, energy transfer is performed based on the energy conversion mode corresponding to the battery switching state of the newly added battery module, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent. This includes: when the energy conversion mode is a discharge conversion mode, determining the transfer output power corresponding to the newly added battery module for the discharge conversion mode; and controlling the energy output of the newly added battery module according to the transfer output power, so that the voltage of the newly added battery module is reduced to be consistent with the voltage of the original energy storage module. Wherein, all battery modules in the photovoltaic energy storage system include: the newly added battery module and the original energy storage module; the transfer output power can be used to characterize the power currently required to be output by the newly added battery module.

[0056] Optionally, in this embodiment of the application, after determining the transfer output power corresponding to the newly added battery module, the newly added battery module can be controlled to transfer electrical energy to the original energy storage module in the photovoltaic energy storage system according to the transfer output power, so that the voltage of the newly added battery module gradually decreases. Then, when the voltage of the newly added battery module decreases to be consistent with the voltage of the original energy storage module, that is, when the voltage of the newly added battery module is equal to the voltage of the original energy storage module, it can be determined that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent.

[0057] In an optional embodiment of this application, the transfer output power can be determined based on a preset rated output power, the load power of the photovoltaic energy storage system, and the photovoltaic power. For example, when the load power is greater than the photovoltaic power, the difference between the load power and the photovoltaic power can be used to determine the transfer output power corresponding to the new battery module. Alternatively, when the load power is equal to the photovoltaic power, the preset rated output power can be directly used as the transfer output power corresponding to the new battery module, so that the new battery module can output according to the rated maximum output power, and transfer electrical energy according to the rated maximum output power, thereby quickly realizing the transfer of electrical energy. Or, when the load power is less than the photovoltaic power, the preset rated output power can be used to subtract the power difference between the photovoltaic power and the load power to determine the transfer input power corresponding to the original energy storage module. The transfer input power corresponding to the original energy storage module can be used to characterize the power of electrical energy currently input to the original energy storage module; the preset rated output power can refer to the maximum output power for the module's electrical energy transfer, such as setting the rated output power of the bidirectional DC / DC converter; the bidirectional DC / DC converter, as an energy storage DC / DC converter in the photovoltaic energy storage system, is electrically connected to the energy storage module in the photovoltaic energy storage system, and can be used to realize the storage and transfer of electrical energy from the battery module.

[0058] Optionally, in this embodiment of the application, determining the transfer output power corresponding to the newly added battery module for the discharge conversion method may specifically include: obtaining a preset rated output power for the discharge conversion method; and determining the transfer output power corresponding to the newly added battery module based on the rated output power of the photovoltaic energy storage system and the photovoltaic power. Specifically, determining the transfer output power corresponding to the newly added battery module based on the rated output power of the photovoltaic energy storage system and the photovoltaic power may include: determining whether the load power is equal to the photovoltaic power; and if the load power is equal to the photovoltaic power, using the rated output power of the newly added battery module as the transfer output power corresponding to the newly added battery module. Alternatively, if the load power is not equal to the photovoltaic power, it is determined whether the load power is less than the photovoltaic power. If the load power is less than the photovoltaic power, a preset rated output power is used, and the power difference between the photovoltaic power and the load power is subtracted to determine the transfer input power corresponding to the original energy storage module. Energy is then transferred to the original energy storage module according to this transfer input power, causing the voltage of the original energy storage module to increase. When the voltage increase of the original energy storage module matches the voltage of the newly added battery module, it is considered that the voltages of all battery modules in the photovoltaic energy storage system are converging. If the load power is greater than the photovoltaic power, the difference between the load power and the photovoltaic power is determined as the transfer output power corresponding to the newly added battery module. The difference between the load power and the photovoltaic power can be used to characterize the power currently required by the energy storage module in the photovoltaic energy storage system; that is, the difference between the load power and the photovoltaic power = load power - photovoltaic power.

[0059] Furthermore, when the energy conversion method is charging conversion, the target transfer power corresponding to the new battery module can be determined based on the comparison between the load power and the photovoltaic power. The output of the original energy storage module is then controlled according to the target transfer power. This allows the new battery module to be recharged based on the energy output of the original energy storage module, causing its voltage to gradually increase until it matches the voltage of the original module. At this point, the voltages of all battery modules in the photovoltaic energy storage system are considered to be consistent. The target transfer power can be used to characterize the power required by the original energy storage module during the recharging process of the new battery module.

[0060] Optionally, in this embodiment of the application, power transfer is performed based on the power conversion mode corresponding to the battery switching state of the newly added battery module, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent. This includes: when the power conversion mode is a charging conversion mode, determining the target transfer power corresponding to the newly added battery module based on the comparison result between the load power and the photovoltaic power for the charging conversion mode; and controlling the original energy storage module to replenish power to the newly added battery module according to the target transfer power, so that the voltage of the newly added battery module rises to be consistent with the voltage of the original energy storage module.

[0061] Specifically, in this embodiment, after determining the target transfer power corresponding to the newly added battery module, the electrical energy of the original energy storage module in the photovoltaic energy storage system can be controlled according to the target transfer power. Based on the electrical energy output by the original energy storage module, the newly added battery module is replenished with power, so that the electrical energy stored in the original energy storage module is transferred to the newly added battery module. That is, the output of the original energy storage module is controlled according to the target transfer power, so that the voltage of the newly added battery module gradually increases. Then, when the voltage of the newly added battery module increases to be consistent with the voltage of the original energy storage module, that is, when the voltage of the newly added battery module is equal to the voltage of the original energy storage module in the photovoltaic energy storage system, it is considered that the voltages of all battery modules in the photovoltaic energy storage system tend to be consistent.

[0062] In one optional implementation, when the power conversion method is a charging conversion method, the target transfer power corresponding to the new battery module is determined based on the comparison result between the load power and the photovoltaic power. Specifically, this may include: determining the energy storage module state of the photovoltaic energy storage system based on the comparison result between the load power and the photovoltaic power; if the energy storage module state is a standby state, determining whether the load power is equal to the photovoltaic power; if the load power is equal to the photovoltaic power, a preset rated output power can be used as the target transfer power corresponding to the new battery module; or, if the load power is not equal to the photovoltaic power, such as when the load power is less than the photovoltaic power, the preset rated output power is used, and the power difference between the photovoltaic power and the load power is subtracted to determine the target transfer power corresponding to the new battery module. The power difference between the photovoltaic power and the load power can be used to characterize the power currently required by the energy storage module in the photovoltaic energy storage system, i.e., the power difference between the photovoltaic power and the load power = load power - photovoltaic power.

[0063] To facilitate understanding of the embodiments of this application, further explanations and descriptions will be provided below in conjunction with the accompanying drawings and specific examples, but these examples do not constitute a limitation on the embodiments of this application.

[0064] As an example of this application, the battery module replacement control method provided in this application can be applied to battery module replacement or capacity expansion scenarios in photovoltaic energy storage systems, enabling the photovoltaic energy storage system to directly replace or expand its battery modules based on the battery modules provided in the embodiments of this application. Figure 3 As shown, before the addition of the battery module, the original energy storage module in the photovoltaic-energy storage integrated machine includes a first battery module and a second battery module. The first and second battery modules can be connected in series to achieve a series connection between energy storage battery BT1 and energy storage battery BT2, as shown below. Figure 4 As shown. Here, energy storage battery BT1 represents the energy storage battery in the first battery module, and energy storage battery BT2 represents the energy storage battery in the second battery module. After the third battery module is connected to the system as a new battery module, as... Figure 4 As shown, the second switch K3 in the third battery module is set to the closed state by default, while the first switch K2, the third switch K4, the fourth switch K5, and the fifth switch K6 are set to the open state by default.

[0065] Assuming that the voltages of the existing battery energy storage modules in the system tend to be consistent: the photovoltaic energy storage system can be an integrated photovoltaic energy storage system that can detect the voltages of the original energy storage modules and the newly added energy storage modules separately. The detected voltage of the original energy storage module can be recorded as the original module voltage V1, and the detected voltage of the newly added energy storage module can be recorded as the new module voltage V2. This allows the circuit connection method of the newly added third battery module to be determined by comparing the magnitudes of the original module voltage V1 and the new module voltage V2.

[0066] For example, after adding a third battery module, a specially designed Active Front End (AFE) chip inside the battery module can monitor the module's voltage and temperature in real time. Based on the information detected by the AFE chip, the original module voltage V1 and the new module voltage V2 can be determined. Specifically, the AFE can detect the total voltage of the first and second battery modules connected in series, using this total voltage as the original module voltage, recorded as V1. The voltage of the third battery module can also be detected and used as the new module voltage, recorded as V2. Subsequently, based on the voltage comparison between the original module voltage V1 and the new module voltage V2, the corresponding circuit connection method for the third battery module can be determined. A switch control signal is then output according to the circuit connection method, allowing the third battery module to be connected to the photovoltaic energy storage system. The specific module replacement control process is as follows: 1) When the voltage of the original module V1 is greater than the voltage of the new module V2, the situation of adding a battery module to the system can be divided into the following three scenarios: In the first scenario: When the integrated photovoltaic and energy storage unit is under load, if the detected load power P1 is greater than the photovoltaic power P2, the energy storage module needs to be added. In this case, the first system switch K1 and the second system switch K0 can be closed, allowing the grid and photovoltaic panels to work simultaneously to provide power to the system. Based on the fact that the original module voltage V1 is greater than the new module voltage V2, and considering that the load power P1 is greater than the photovoltaic power P2, the circuit bypass access method can be determined as the circuit access method for the new battery module. Based on the circuit bypass access method, a bypass switch control signal is output to the new third battery module. The bypass switch control signal controls the state of each battery switch in the new third battery module, keeping the second switch K3 in the new third battery module closed, while the first switch K2, the third switch K4, the fourth switch K5, and the fifth switch K6 are in the open state. This puts the new third battery module in a bypass state, thus avoiding the problem of low voltage protection of the energy storage system caused by excessive voltage difference between the original module and the new module, which would affect the user experience.

[0067] The second scenario: When the integrated photovoltaic and energy storage unit is under load, if the load power P1 equals the photovoltaic power P2, then the energy storage module is in standby mode. In this case, the first system switch K1 can be closed, and the second system switch K0 can be opened, resulting in the first system switch K1 being closed and the second system switch K0 being open. Based on the fact that the original module voltage V1 is greater than the new module voltage V2, and considering that the load power P1 equals the photovoltaic power P2, the power transfer access method is determined as the circuit access method for the new battery module. Based on this power transfer access method, a transfer switch control signal is output to the newly added third battery module. This transfer switch control signal controls the state of each battery switch within the newly added third battery module, causing the second switch K3, the fourth switch K5, and the fifth switch K6 within the newly added third battery module to close, and the first switch K2 and the third switch K4 to open. That is, the second switch K3, the fourth switch K5, and the fifth switch K6 within the newly added third battery module are in the closed state. Figure 4As shown, in the newly added third battery module, the second switch K3, the fourth switch K5, and the fifth switch K6 are closed, while the first switch K2 and the third switch K4 are open. This allows the electrical energy from the first and second battery modules to be transferred to the newly added third battery module via a bidirectional DC / DC converter at its maximum rated power P3. The maximum rated power P3 is used as the target transfer power, ensuring that the electrical energy in the original energy storage module can be transferred to the newly added third battery module at its maximum rated power P3 after bidirectional DC / DC conversion. This continues until the voltages of all battery modules become consistent. Finally, the second switch K3, the fourth switch K5, and the fifth switch K6 in the third battery module are opened, while the first switch K2 and the third switch K4 in the third battery module are closed, switching the battery switch state of the newly added third battery module to the preset target switch state. Figure 5 As shown, the addition of a new battery module allows the newly added third battery module to be connected in series with other battery modules in the system. This enables battery module replacement or capacity expansion based on the series connection of battery modules, thus solving the problem in the prior art where the battery module cannot be expanded due to the inability to determine the changes in the internal resistance of each battery module.

[0068] The third scenario: When the photovoltaic-storage integrated unit is under load, if the detected load power P1 is less than the photovoltaic power P2, or if the integrated unit is in standby mode and the energy storage module is in standby mode, the first system switch K1 and the second system switch K0 can be closed. Based on the condition that the original module voltage V1 is greater than the new module voltage V2, and considering that the load power P1 is less than the photovoltaic power P2, the power transfer access method is determined as the circuit access method for the new battery module. Based on this power transfer access method, a transfer switch control signal is output to the newly added third battery module. This transfer switch control signal controls the state of each battery switch within the newly added third battery module, causing the second switch K3, the fourth switch K5, and the fifth switch K6 within the newly added third battery module to close, and the first switch K2 and the third switch K4 to open. Figure 4As shown, the energy from the first and second battery modules can be transferred to the original energy storage module via bidirectional DC / DC converter, with the power difference (P2-P1) between the photovoltaic power P2 and the load power P1. This means that energy transfer between the old and new modules is achieved through photovoltaic power supplementation and module priority control. Specifically, the target transfer power can be obtained by subtracting the power difference (P2-P1) between the photovoltaic power P2 and the load power P1 from the preset rated output power P3. That is, the target transfer power = rated output power P3 - (photovoltaic power P2 - load power P1). This allows the energy in the original energy storage module to be transferred to the newly added third battery module via bidirectional DC / DC converter with a power value of P3 - (P2-P1) as the target transfer power, until the voltages of all battery modules are consistent. Finally, the second switch K3, the fourth switch K5, and the fifth switch K6 in the newly added third battery module are disconnected, and the first switch K2 and the third switch K4 in the newly added third battery module are closed. Figure 5 As shown, this allows the newly added third battery module to be connected in series with other battery modules in the system, thus completing the addition of the new battery module.

[0069] 2) When the voltage of the original module V1 is less than the voltage of the new module V2, the situation of adding a battery module to the system can be divided into the following three scenarios: Scenario 1: When the photovoltaic-energy storage integrated unit is under load, and the load power P1 is greater than the photovoltaic power P2, the energy storage module in the photovoltaic-energy storage system starts working. At this time, the first system switch K1 and the second system switch K0 can be closed, allowing the grid and photovoltaic panels to work simultaneously. Based on the fact that the original module voltage V1 is less than the new module voltage V2, and considering that the load power P1 is greater than the photovoltaic power P2, the circuit power supply access method is determined to be the circuit access method for the newly added battery module. Based on the circuit power supply access method, a power supply switch control signal is output to the newly added third battery module. This power supply switch control signal controls the state of each battery switch in the newly added third battery module, causing the fourth switch K5 and the fifth switch K6 in the newly added third battery module to enter the closed state, i.e., closing the fourth switch K5 and the fifth switch K6 in the newly added third battery module, and opening the first switch K2, the second switch K3, and the third switch K4 in the newly added third battery module. Figure 6 As shown, the first switch K2, the second switch K3, and the third switch K4 in the newly added third battery module are in the open state, thereby causing the newly added third battery module to enter the discharge working state. The output power is transferred through a bidirectional DC / DC converter with a power value of P1-P2 until the voltage of all battery modules tends to be consistent. Finally, the second switch K3, the fourth switch K5, and the fifth switch K6 in the third battery module are opened, and the first switch K2 and the third switch K4 in the third battery module are closed. Figure 5 As shown.

[0070] The second scenario: When the integrated photovoltaic and energy storage unit is under load, and the load power P1 equals the photovoltaic power P2, the energy storage module is in standby mode. At this time, the first system switch K1 is closed, and the second system switch K0 is open. This allows the newly added third battery module to transfer power between the old and new battery modules via bidirectional DC / DC. Specifically, based on the fact that the original module voltage V1 is less than the new module voltage V2, and considering that the load power P1 equals the photovoltaic power P2, the power output access method can be determined as the circuit access method for the newly added third battery module. Based on this power output access method, a transfer switch control signal is output to the newly added third battery module. This transfer switch control signal controls the state of each battery switch within the newly added third battery module, causing the second switch K3, fourth switch K5, and fifth switch K6 within the newly added third battery module to close, and the first switch K2 and third switch K4 within the newly added third battery module to open. Figure 4 As shown, this allows the electrical energy in the newly added third battery module to be transferred to the original energy storage module via a bidirectional DC / DC converter at its maximum rated power P3. Specifically, the maximum rated power P3 is used as the transfer output power, allowing the electrical energy in the original energy storage module to be transferred to it at its maximum rated power P3 after passing through the bidirectional DC / DC converter. This continues until the voltages of all battery modules in the system become consistent. Finally, the second switch K3, the fourth switch K5, and the fifth switch K6 in the newly added third battery module are disconnected, and the first switch K2 and the third switch K4 in the newly added third battery module are closed. Figure 5 As shown, this allows the newly added third battery module to be connected in series with other battery modules in the system, thus completing the addition of the new battery module.

[0071] In the third scenario, when the integrated photovoltaic and energy storage unit is under load, and the load power P1 is less than the photovoltaic power P2, or when the integrated photovoltaic and energy storage unit is in standby mode, the energy storage module is also in standby mode. In this case, the first system switch K1 and the second system switch K0 can be closed, ensuring that the first system switch K1 and the second system switch K0 are closed. Based on the fact that the original module voltage V1 is less than the new module voltage V2, and considering that the load power P1 is less than the photovoltaic power P2, the parallel connection method of the circuit is determined as the circuit connection method for the new battery module. Based on the parallel connection method, a transfer switch control signal is output to the newly added third battery module. This transfer switch control signal controls the state of each battery switch in the newly added third battery module, causing the second switch K3, the fourth switch K5, and the fifth switch K6 in the newly added third battery module to close, and the first switch K2 and the third switch K4 to open. Figure 4As shown, the photovoltaic power output from the photovoltaic DC / DC converter can be used to supplement the original energy storage module based on the power difference (P2-P1) between the photovoltaic power P2 and the load power P1 via a bidirectional DC / DC converter. The power difference (P2-P1) can be subtracted from the preset rated output power P3 to obtain the corresponding transfer input power for the original energy storage module. That is, the transfer input power for the original energy storage module = rated output power P3 - (photovoltaic power P2 - load power P1). This allows the electrical energy in the newly added third battery module to be transferred to the original energy storage module via a bidirectional DC / DC converter with a transfer input power of P3-(P2-P1) until the voltages of all battery modules become consistent. Finally, the second switch K3, the fourth switch K5, and the fifth switch K6 in the newly added third battery module are disconnected, and the first switch K2 and the third switch K4 in the newly added third battery module are closed. Figure 5 As shown, this allows the newly added third battery module to be connected in series with other battery modules in the system, thus completing the addition of the new battery module.

[0072] In summary, the battery module provided in this application includes an energy storage battery and a battery switch module, and the battery switch module includes at least five battery switches. After adding a new battery module, the voltage of the original module and the voltage of the new module are detected. Based on the voltage of the original module and the voltage of the new module, combined with the load power and photovoltaic power of the photovoltaic energy storage system, the circuit access method corresponding to the new battery module is determined. According to the circuit access method, the state of each battery switch in the new battery module is controlled according to the switch control signal. Based on the power conversion method corresponding to the battery switch state of the new battery module, photovoltaic supplementation and module optimization are used to achieve the desired power conversion. First, the power transfer between the newly added battery module and the original energy storage module is achieved via DC-DC converter. This transfer ensures that the voltage of all battery modules in the photovoltaic energy storage system becomes consistent. Once the voltage of all battery modules in the photovoltaic energy storage system is consistent, the battery switch state of the newly added battery module is set to a preset target switch state. This allows for the automatic addition of new battery modules based on the target switch state, eliminating the need for manual voltage adjustment. Consequently, it reduces the difficulty of battery module replacement and capacity expansion, simplifying battery module installation steps and reducing installation time and costs.

[0073] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should know that the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps may be performed in other orders or simultaneously.

[0074] like Figure 7As shown, this application embodiment also provides a photovoltaic energy storage system, which includes a module replacement control device 710 and various battery modules 720 electrically connected to the module replacement control device 710. The battery modules 720 are the battery modules provided in any of the foregoing embodiments of this application. The module replacement control device 710 is configured to implement the battery module replacement control method provided in any of the foregoing embodiments of this application, so that after a new battery module is added to the photovoltaic energy storage system, the original module voltage and the new module voltage are detected. Based on the original module voltage and the new module voltage, combined with the load power and photovoltaic power of the photovoltaic energy storage system, the circuit access method corresponding to the newly added battery module is determined, and the new battery module is controlled according to the circuit access method based on the switch control signal. The state of each battery switch in the added battery module is determined by the energy conversion method corresponding to the battery switch state of the added battery module. This is achieved through photovoltaic power supplementation, module priority control, and energy transfer between the added battery module and the original energy storage module via a bidirectional DC-DC converter. This process ensures that the voltage of all battery modules in the photovoltaic energy storage system is consistent. When the voltage of all battery modules in the photovoltaic energy storage system is consistent, the battery switch state of the added battery module is set to a preset target switch state. This allows for the automatic addition of the new battery module based on the target switch state, eliminating the need for manual adjustment of the module voltage. Consequently, it reduces the difficulty of battery module replacement and capacity expansion, thereby simplifying the battery module installation process and reducing installation time and costs.

[0075] Optionally, the photovoltaic energy storage system provided in this application embodiment may include other electrical devices in addition to the battery module 720 and the module replacement control device 710, such as photovoltaic panels, bidirectional DC-DC converters, photovoltaic DC-DC converters, and grid AC-DC converters. This application embodiment does not impose specific limitations on this.

[0076] In one optional embodiment of this application, the first terminal of the bidirectional DC-DC converter is electrically connected to the second positive terminal of the battery module, the second terminal of the bidirectional DC-DC converter is electrically connected to the first negative terminal of the battery module, the third terminal of the bidirectional DC-DC converter is electrically connected to the second negative terminal of the battery module, the fourth terminal of the bidirectional DC-DC converter is electrically connected to the first positive terminal of the battery module, the DC terminal of the bidirectional DC-DC converter is electrically connected to the output terminal of the photovoltaic DC-DC converter and the DC terminal of the grid AC-DC converter, respectively; the input terminal of the photovoltaic DC-DC converter is electrically connected to the output terminal of the photovoltaic panel.

[0077] Among them, the bidirectional DC-DC converter can be used as an energy storage DC / DC converter that is electrically connected to the battery module in the system. Specifically, it can be used for the transfer of DC power, such as by using photovoltaic power supplementation and module priority control to achieve the transfer of power between new and old modules.

[0078] As an example of this application, the bidirectional DC-DC converter 810 may include two bidirectional buck-boost circuits, namely a first bidirectional buck-boost circuit 811 and a second bidirectional buck-boost circuit 812, such as... Figure 8 As shown; optionally, the circuit structures of the first bidirectional buck-boost circuit 811 and the second bidirectional buck-boost circuit 812 are the same. For example, if the first bidirectional buck-boost circuit 811 and the second bidirectional buck-boost circuit adopt the same bidirectional BUCK-BOOST circuit, this application example does not limit this.

[0079] One end of the first bidirectional buck-boost circuit 811 is used to connect to the DC bus of the photovoltaic energy storage system, so as to electrically connect to the photovoltaic DC / DC converter in the photovoltaic energy storage system through the DC bus. The other end of the bidirectional first buck-boost circuit 811 is used to connect to the new battery pack NEW, so that the first bidirectional buck-boost circuit 811 can charge the new battery pack NEW according to the photovoltaic power output by the photovoltaic DC / DC converter.

[0080] One end of the second bidirectional buck-boost circuit 812 is used to connect to the original energy storage module OLD of the photovoltaic energy storage system, and the other end of the second bidirectional buck-boost circuit 812 is used to connect to the new battery pack NEW. The second bidirectional buck-boost circuit 812 is configured to realize the transfer of electrical energy between the original energy storage module OLD and the new battery pack NEW.

[0081] For example, if the voltage V1 of the original module is greater than the voltage V2 of the new module, and if the energy of the original energy storage module is transferred to the new energy storage module through the bidirectional DC-DC converter, then the second bidirectional buck-boost circuit 812 of the bidirectional DC-DC converter needs to convert the high voltage to the low voltage, which is a buck output. The specific process is as follows: In the first stage, the first control switch S1 and the second control switch S5 of the second bidirectional buck-boost circuit 812 in the bidirectional DC-DC converter are closed, so that the output voltage of the second bidirectional buck-boost circuit 812 is connected to the new battery module NEW; and the third control switch S9 and the fourth control switch S10 of the second bidirectional buck-boost circuit 812 in the bidirectional DC-DC converter can be closed, so that the input voltage provided by the original energy storage module OLD can be connected through the closed third control switch S9 and the fourth control switch S10, and then the original module voltage V1 can be used to charge the first capacitor C4. In the second stage, the second switch Q12 of the first bridge arm in the second bidirectional buck-boost circuit 812 is turned on, and the first switch Q11 is turned off. This causes the first freewheeling diode D1 and the second freewheeling diode D2 in the second bidirectional buck-boost circuit 812 to be in the off state, and the first inductor LA to be in the charging state. The charging voltage is (U0-Vm-E), the charging current is I3, the charging time is toff1, and the charging energy is (U0-Vm-E)*I3*toff1. Wherein, U0 represents the voltage across the first capacitor C4; Vm is used to represent the on-state voltage drop of the Most transistor. In this example, the first switch Q11, the second switch Q12, the third switch Q13, and the second switch Q14 can all be implemented using the Most transistor. Therefore, the on-state voltage drops of the first switch Q11, the second switch Q12, the third switch Q13, and the second switch Q14 can all be Vm; E represents the voltage across the second capacitor C6. In the third stage, the third switch Q13 of the second bridge arm in the second bidirectional buck-boost circuit 812 is turned on and the fourth switch Q14 is turned off, so that the third switch Q13 is turned on and the fourth switch Q14 is turned off, the second inductor LB is in the discharge state, the discharge time is ton2, the discharge current is I4, considering the forward voltage drop Vd of the third freewheeling diode D3, the inductance voltage of the second inductor LB is E+Vd, and the discharge energy is (E+Vd)*I4*ton2; In the fourth stage, the first switch Q11 of the first bridge arm in the second bidirectional buck-boost circuit 812 is turned on and the second switch Q12 is turned off, so that the first freewheeling diode D1 in the second bidirectional buck-boost circuit 812 is turned on and the second freewheeling diode D2 is turned off. The first inductor LA is in a discharging state, the discharging time is ton1, the inductance voltage of the first inductor LA is (E+Vd), and the discharging energy is (E+Vd)*I3*ton1. In the fifth stage, the fourth switch Q14 of the second bridge arm in the second bidirectional buck-boost circuit 812 is turned on, and the third switch Q13 is turned off, so that the third freewheeling diode D3 and the fourth freewheeling diode D4 are in the off state, the second inductor LB is in the charging state, the charging voltage is (U0-Vm-E), the charging current is I4, the charging time is toff2, and the energy absorbed by the second inductor LB is (U0-Vm-E)*I4*toff2; Since the total energy absorbed and released by the first inductor LA and the second inductor LB in the same bidirectional buck-boost circuit 812 within one cycle is equal, i.e. (U0-Vm-E)*I3*toff+(U0-Vm-E)*I4*toff2 = (E+Vd)*I4*ton2+(E+Vd)*I3*ton1, and since ton1 = ton2, toff1 = toff2, and I3 = I4, the voltage reduction can be achieved by adjusting the duty cycle of the charging time toff1.

[0082] For example, if the voltage V1 of the original module is less than the voltage V2 of the new module, and if the energy of the original energy storage module can be transferred to the new energy storage module through the bidirectional DC-DC converter, then the second bidirectional buck-boost circuit 812 of the bidirectional DC-DC converter needs to convert the low voltage to a high voltage, which is a boost output. The specific process is as follows: In the first stage, the first switch Q11 of the first bridge arm in the second bidirectional buck-boost circuit 812 is turned on and the second switch Q12 is turned off, which makes the first freewheeling diode D1 and the second freewheeling diode D2 turn off. The first inductor LA starts to charge. Due to the presence of the Most transistor's on-state voltage drop Vm, the charging voltage is E-Vm, the charging current is I3, the charging time is ton1, and the energy obtained by the first inductor LA is (E-Vm)*I3*ton1. In the first stage, the third switch Q13 of the second bridge arm in the second bidirectional buck-boost circuit 812 is cut off, the fourth switch Q14 is turned on, the fourth freewheeling diode D4 is turned on, and the third freewheeling diode D3 is cut off. The voltage of the second inductor LB is (E-Vd-U0), which is opposite to the current direction. The inductor discharges. Due to the current-holding effect of the inductor, the magnitude and direction of the current remain unchanged. The discharge energy of the inductor is (U0+Vd-E)*toff2*I4. In the third stage, the second switch Q12 of the first bridge arm in the second bidirectional buck-boost circuit 812 is turned on, and the first switch Q11 is turned off, causing the first freewheeling diode D1 to be turned off and the second freewheeling diode D2 to be turned on. The first inductor LA begins to discharge. Due to the presence of the freewheeling diode forward voltage drop Vd, the discharge voltage is (E-Vd-U0), the discharge current is I3, and the discharge time is toff1. The energy released by the first inductor LA is (U0+Vd-E)*toff1*I3. At the same time, the third switch Q13 of the second bridge arm in the second bidirectional buck-boost circuit 812 is turned on, and the fourth switch Q14 is turned off. The third freewheeling diode D3 and the fourth freewheeling diode D4 are turned off, and the second inductor LB is charged. Due to the presence of the Most transistor forward voltage drop Vm, the charging voltage is E-Vm, the charging current is I4, and the charging time is ton2. The charging energy of the second inductor LB is (E-Vm)*I4*ton2.

[0083] Since the pulse-width modulation (PWM) drive waveforms of the charging and discharging paths have the same frequency, i.e., ton1=ton2 and toff1=toff2, according to the calculation formula of the energy absorbed and released by the first inductor LA and the second inductor LB in one cycle, (E-Vm)*I3*ton1 + (E-Vm)*I4*ton2 = (U0+Vd-E)*toff1*I3+(U0+Vd-E)*toff2*I4, boost transmission can be achieved by adjusting the duty cycle of the PWM signal.

[0084] The duty cycle of the PWM signal can be determined by the charging time ton1 and the discharging time toff1. The PWM signal can be used to control the on and off of the first switch Q11, the second switch Q12, the third switch Q13 and the second switch Q14, so as to control the charging time ton1 and the discharging time toff1, realize the conversion function of low voltage transmission or high voltage output, and thus meet the DC-DC conversion requirements.

[0085] It should be noted that the photovoltaic energy storage system provided above can execute the battery module replacement control method provided in any embodiment of this application, and has the corresponding functions and beneficial effects of the execution method.

[0086] In practical implementation, the photovoltaic energy storage system can be integrated into electrical equipment. When a new battery module is added, the system can detect the voltages of the original and new modules. Based on these voltages, combined with the load power and photovoltaic power of the photovoltaic energy storage system, the system determines the circuit connection method for the new battery module. According to the circuit connection method, the system controls the state of each battery switch in the new battery module based on switch control signals. Energy transfer is performed based on the corresponding energy conversion methods of the new battery module's battery switch states, including photovoltaic power supplementation, module priority control, and energy transfer between the new battery module and the original energy storage module via DC-DC converter. This ensures that the voltages of all battery modules in the photovoltaic energy storage system are consistent. When the voltages of all battery modules in the photovoltaic energy storage system are consistent, the battery switch state of the new battery module is set to a preset target switch state. This allows for automatic addition of the new battery module based on the target switch state, eliminating the need for manual voltage adjustment. This reduces the difficulty of battery module replacement and capacity expansion, simplifying battery module installation steps and reducing installation time costs.

[0087] like Figure 9As shown, this application embodiment provides an electrical device, including a processor 111, a communication interface 112, a memory 113, and a communication bus 114. The processor 111, the communication interface 112, and the memory 113 communicate with each other through the communication bus 114. The memory 113 is used to store computer programs. When the processor 111 executes the program stored in the memory 113, it implements the steps of the battery module replacement control method provided in any of the aforementioned method embodiments.

[0088] In one embodiment of this application, when the processor 111 executes the program stored in the memory 113, it implements the battery module replacement control method provided in any of the aforementioned method embodiments, including: when a new battery module is added to the photovoltaic energy storage system, determining the original module voltage and the new module voltage; based on the original module voltage and the new module voltage, combined with the load power and photovoltaic power of the photovoltaic energy storage system, determining the circuit access method corresponding to the new battery module; outputting a switch control signal according to the circuit access method, the switch control signal being used to control the state of each battery switch in the new battery module; performing energy transfer based on the energy conversion method corresponding to the battery switch state of the new battery module, so that the voltage of all battery modules in the photovoltaic energy storage system tends to be consistent; when the voltage of all battery modules tends to be consistent, setting the battery switch state to a preset target switch state.

[0089] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the battery module replacement control method provided in any of the foregoing method embodiments.

[0090] The system, device, and medium embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0091] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0092] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0093] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A battery module, characterized by, The application relates to a battery switching module for a photovoltaic energy storage system. The battery switching module comprises at least five battery switches, and the battery switching module is configured to control the state of each battery switch in the battery switching module according to a switching control signal, so that the energy storage battery is connected to a circuit system in a circuit connection mode corresponding to the battery module. The at least five battery switches comprise a first switch, a second switch, a third switch, a fourth switch and a fifth switch. The positive terminal of the energy storage battery is electrically connected to the first terminal of the first switch and the first terminal of the fourth switch, and the negative terminal of the energy storage battery is electrically connected to the first terminal of the third switch and the first terminal of the fifth switch. The second terminal of the first switch is electrically connected to the first terminal of the second switch, serving as a first positive terminal of the battery module. The second terminal of the fourth switch serves as a second positive terminal of the battery module, and the second terminal of the second switch is electrically connected to the second terminal of the third switch, serving as a first negative terminal of the battery module. The second terminal of the fifth switch serves as a second negative terminal of the battery module. The second switch is a normally closed switch.

2. The battery module of claim 1, wherein, The first switch, the third switch, the fourth switch and the fifth switch are normally open switches. In the case that a new battery module is added to a photovoltaic energy storage system, the voltage of an original module and the voltage of a new module are determined.

3. A replacement control method of a battery module, characterized by, Based on the voltage of the original module and the voltage of the new module, in combination with the load power and the photovoltaic power of the photovoltaic energy storage system, the circuit connection mode corresponding to the new battery module is determined. According to the circuit connection mode, a switching control signal is output, and the switching control signal is used to control the state of each battery switch in the new battery module. Based on the battery switch state of the new battery module, the electrical energy conversion mode corresponding to the battery switch state is determined, and electrical energy is transferred, so that the voltages of all battery modules in the photovoltaic energy storage system tend to be consistent. In the case that the voltages of all battery modules tend to be consistent, the battery switch state is set to a preset target switch state. The method comprises the following steps: The voltage of the original module is compared with the voltage of the new module to obtain a voltage comparison result.

4. The method of claim 3, wherein, The voltage comparison result is used to determine the electrical energy conversion mode corresponding to the new battery module. Based on the electrical energy conversion mode, the comparison result between the load power and the photovoltaic power is used to determine the circuit connection mode of the new battery module. The method comprises the following steps: The comparison result between the load power and the photovoltaic power is used to determine the energy storage module state.

5. The method of claim 4, wherein, In the case that the energy storage module state is an energy storage module working state, the electrical energy conversion mode is used to determine the circuit connection mode of the new battery module. ​ ​ 6. The method according to any one of claims 3 to 5, characterized in that, The all battery modules in the photoelectric energy storage system include the new battery module and the original energy storage module, and the electrical energy is transferred based on the electrical energy conversion mode corresponding to the battery switch state of the new battery module, so that the voltages of all battery modules in the photoelectric energy storage system tend to be consistent, including: In the case of the electrical energy conversion mode being a discharge conversion mode, the transfer output power corresponding to the new battery module is determined for the discharge conversion mode; According to the transfer output power, the electrical energy output of the new battery module is controlled to reduce the voltage of the new battery module to be consistent with the voltage of the original energy storage module.

7. The method according to any one of claims 3 to 5, characterized in that, The all battery modules in the photoelectric energy storage system include the new battery module and the original energy storage module, and the electrical energy is transferred based on the electrical energy conversion mode corresponding to the battery switch state of the new battery module, so that the voltages of all battery modules in the photoelectric energy storage system tend to be consistent, including: In the case of the electrical energy conversion mode being a charge conversion mode, the target transfer power corresponding to the new battery module is determined based on the comparison result between the load power and the photovoltaic power for the charge conversion mode; According to the target transfer power, the original energy storage module is controlled to supply power to the new battery module to increase the voltage of the new battery module to be consistent with the voltage of the original energy storage module.

8. A photoelectric energy storage system, characterized by, The photoelectric energy storage system includes a module replacement control device and each battery module electrically connected to the module replacement control device, the battery module is the battery module as claimed in any one of claims 1 to 2, and the module replacement control device is configured to implement the battery module replacement control method as claimed in any one of claims 3 to 7.

9. The photoelectric energy storage system of claim 8, wherein, The photoelectric energy storage system further includes a photovoltaic panel, a bidirectional DC converter, a photovoltaic DC-DC converter, and a grid AC-DC converter. The first end of the bidirectional DC converter is electrically connected to the second positive electrode end of the battery module, the second end of the bidirectional DC converter is electrically connected to the first negative electrode end of the battery module, the third end of the bidirectional DC converter is electrically connected to the second negative electrode end of the battery module, the fourth end of the bidirectional DC converter is electrically connected to the first positive electrode end of the battery module, and the DC ends of the bidirectional DC converter are respectively electrically connected to the output end of the photovoltaic DC-DC converter and the DC end of the grid AC-DC converter. The input end of the photovoltaic DC-DC converter is electrically connected to the output end of the photovoltaic panel.

10. An electrical appliance, characterized in that It includes: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory is used to store a computer program; the processor is used to execute the program stored on the memory to realize the steps of the battery module replacement control method as claimed in any one of claims 3 to 7.

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