energy storage system

Abstract

This application discloses an energy storage system including multiple battery packs. The battery packs are divided into a main pack and at least one expansion pack. Both the main pack and the expansion pack include a cell module, a battery management module, and at least one expansion port. The main pack and the expansion pack are electrically connected via the expansion port. The main pack also includes a control motherboard electrically connected to the battery management module. The control motherboard is also electrically connected to the battery management module of each expansion pack via the expansion port. The control motherboard is configured to provide a preset voltage to the battery management module of each battery pack and select one battery pack as the target battery pack, which supplies power to the energy storage system. The battery management module is electrically connected to both the cell module and the expansion port, and either the cell module or the expansion port can supply power to the battery management module. Thus, by electrically connecting the battery management module of each battery pack to both the cell module and the expansion port, the battery pack avoids power depletion due to continuous power consumption by the battery management module, improving the safety of the energy storage system.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an energy storage system. Background Technology

[0002] Portable energy storage systems are portable power devices that can store electrical energy and power various devices when needed. They have become increasingly common for outdoor travel or short trips, and some are even used for home backup power. To meet the high power consumption of household appliances, the industry generally uses a parallel battery pack (power pack) solution to expand capacity.

[0003] However, when using solar panels (PV) for charging, this capacity expansion solution may encounter situations where the PV input power is lower than the device system's own standby and operating power consumption (self-discharge) during prolonged cloudy weather. This can cause the device to not only fail to charge but also continue to discharge, eventually depleting its power and causing severe battery depletion. Furthermore, in low-temperature environments, due to the inherent characteristic that lithium batteries cannot be safely charged at low temperatures, the system will forcibly prohibit charging; at this time, regardless of the input power provided by the PV, the device cannot utilize it for charging. In low-temperature scenarios where PV is required as the primary or sole charging source, the device system's self-discharge will continuously consume battery power, similarly leading to battery depletion (battery depletion), affecting device availability and even damaging the battery. Utility Model Content

[0004] This application provides an energy storage system.

[0005] This application implements an energy storage system including multiple battery packs. The multiple battery packs are divided into a main pack and at least one expansion pack. Both the main pack and the expansion pack include a cell module, a battery management module, and at least one expansion port. The main pack and the expansion pack are electrically connected through the expansion port. The main pack also includes a control motherboard electrically connected to the battery management module. The control motherboard is also electrically connected to the battery management module of each expansion pack through the expansion port. The control motherboard is configured to provide a preset voltage to the battery management module of each battery pack and select one of the battery packs as a target battery pack. The target battery pack can supply power to the energy storage system through the expansion port.

[0006] The battery management module of each battery pack is electrically connected to the cell module and the expansion port, respectively, and the cell module or the expansion port can supply power to the battery management module.

[0007] In some embodiments, each of the battery packs further includes:

[0008] The first diode has its positive terminal connected to the expansion port and its negative terminal connected to the battery management module;

[0009] The second diode has its positive terminal connected to the positive terminal of the battery cell module and its negative terminal connected to the battery management module.

[0010] In some embodiments, each of the battery packs further includes:

[0011] The resistor is connected at one end to the expansion port and at the other end to the battery management module.

[0012] In some embodiments, the control motherboard includes a detection unit and a control unit, the detection unit being electrically connected to the control unit, and the detection unit being configured to detect ambient temperature; the control unit is configured to:

[0013] When the ambient temperature is less than or equal to a preset temperature and the energy storage system is connected to a solar panel, a first control command is sent to the battery management module of the main pack, so that the main pack acts as the target battery pack to supply power to the energy storage system.

[0014] In some embodiments, the control unit is further configured to:

[0015] Obtain the SOC of the expansion pack from the battery management module of each expansion pack;

[0016] When the SOC of the main battery pack is less than or equal to a preset threshold, a second control command is sent sequentially to the battery management module of the expansion pack according to the SOC size of the expansion pack, so that the expansion pack is used as the target battery pack in sequence.

[0017] In some embodiments, the control unit is further configured to:

[0018] If the SOC of each battery pack is less than or equal to a preset threshold, a power loss prevention program is activated to shut down the energy storage system.

[0019] In some embodiments, the control unit is further configured to:

[0020] When the ambient temperature is higher than the preset temperature, a start command is sent to each of the battery management modules to power on the energy storage system.

[0021] In some implementations, the preset voltage is 5V.

[0022] In some embodiments, the energy storage system further includes:

[0023] An expansion bus connects the two expansion ports.

[0024] In some embodiments, the energy storage system further includes:

[0025] A solar charging module, one end of which is connected to the battery management module and the other end of which is connected to a solar panel, is used to convert sunlight into direct current electricity through the photovoltaic effect.

[0026] In the energy storage system implemented in this application, a preset voltage is provided to the battery management modules of all battery packs by the control motherboard, thereby providing a power source for all isolated CAN communications. When charging is activated, this preset voltage can serve as an activation signal for the battery management modules. Furthermore, each battery management module is given a dual protection mechanism, drawing power from either its local cell module or the system bus (expansion port). This ensures that even if a single battery pack's cell module cannot supply power due to deep discharge (e.g., insufficient PV charging on cloudy days), low-temperature protection (charging prohibited below 0°C), or internal faults, its battery management module can still continue to operate. Simultaneously, the control motherboard dynamically selects the target battery pack with the optimal state to supply power to the system through the expansion port. This fundamentally solves the risk of local BMS power failure and system control failure caused by environmental or abnormal conditions in multi-pack parallel applications, significantly improving the core control stability, communication reliability, and overall availability of the energy storage system under harsh operating conditions. Attached Figure Description

[0027] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic diagram of the energy storage system according to certain embodiments of this application.

[0029] Figure 2 This is a partial circuit diagram of an energy storage system according to certain embodiments of this application. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0031] Portable energy storage systems are portable power devices that store electrical energy and power various devices when needed. They have become increasingly common for outdoor travel and short trips, and some are even used for home backup power. However, household appliances generally consume a lot of power, making standard portable energy storage systems insufficient. To meet the high power consumption of household appliances, the industry commonly uses parallel battery packs (additional battery packs) to expand the capacity of home backup power.

[0032] However, when using solar panels (PV) for charging, this capacity expansion solution may encounter situations where the PV input power is lower than the device system's own standby and operating power consumption (self-discharge) during prolonged cloudy weather. This can cause the device to not only fail to charge but also continue to discharge, eventually depleting its power and causing severe battery depletion. Furthermore, in low-temperature environments, due to the inherent characteristic that lithium batteries cannot be safely charged at low temperatures, the system will forcibly prohibit charging; at this time, regardless of the input power provided by the PV, the device cannot utilize it for charging. In low-temperature scenarios where PV is required as the primary or sole charging source, the device system's self-discharge will continuously consume battery power, similarly leading to battery depletion (battery depletion), affecting device availability and even damaging the battery.

[0033] In view of this, please refer to Figure 1 This application provides an energy storage system 100, which includes multiple battery packs 10. The multiple battery packs 10 are divided into a main pack and at least one expansion pack. Both the main pack and the expansion pack include a cell module 101, a battery management module 102, and at least one expansion port 103. The main pack and the expansion pack are electrically connected through the expansion port 103. The main pack also includes a control motherboard 105 electrically connected to the battery management module 102. The control motherboard 105 is also electrically connected to the battery management module 103 of each expansion pack through the expansion port 103. The control motherboard 105 is configured to provide a preset voltage to the battery management module 102 of each battery pack 10 and select one of the battery packs 10 as the target battery pack. The target battery pack can supply power to the energy storage system 100 through the expansion port 103. The battery management module 102 of each battery pack 10 is electrically connected to the cell module 101 and the expansion port 103, respectively. The cell module 101 or the expansion port 103 can supply power to the battery management module 102.

[0034] In the energy storage system 100 of this application embodiment, a preset voltage is provided to the battery management modules 102 of all battery packs 10 by the control motherboard 105, thereby providing a power source for isolated CAN communication. When charging is activated, the preset voltage can be used as an activation signal for the battery management modules 102. Each battery management module 102 is given a dual guarantee mechanism that draws power from the local cell module 101 or the expansion bus (expansion port), ensuring that even if a single battery pack 10 cannot be powered by its cell module 101 due to deep discharge (such as insufficient PV charging on cloudy days), low temperature protection (charging is prohibited below 0°C), or internal fault, its battery management module 102 can still continue to operate. At the same time, the control motherboard 105 dynamically selects the target battery pack 10 with the best state to supply power to the system through the expansion port 105, solving the risk of local BMS power failure and system runaway caused by environmental or abnormal conditions in multi-pack parallel applications, and significantly improving the core control stability, communication reliability, and overall availability of the energy storage system 100 under harsh operating conditions.

[0035] It should be noted that the energy storage system 100 can be a portable energy storage system. For example, in this embodiment, the energy storage system can be a portable photovoltaic energy storage system. The photovoltaic energy storage system can convert light energy into electrical energy and store it, as well as supply electrical energy to the load. That is, the photovoltaic energy storage system takes into account the functions of photoelectric conversion, electrical energy storage, and discharge.

[0036] The energy storage system 100 may include at least one expansion bus and multiple battery packs 10. The number of battery packs 10 can be 2, 3, 4, 5, 6, 8, 10, or even more; the specifications of the multiple battery packs 10 can be the same or different. The multiple battery packs 10 can be divided into a main pack and at least one expansion pack. When there are multiple expansion packs, they can be connected in parallel to the main pack via the expansion bus, which enables communication and power transfer between the main pack and the expansion packs. (See also...) Figure 1 In this embodiment, six battery packs 10 can be used as an example. One battery pack 10 serves as the main pack, and the other five battery packs 10 serve as expansion packs. The main pack and the five expansion packs can be electrically connected through an expansion bus.

[0037] Please refer to further information. Figure 1 and Figure 2 Each battery pack 10 may include a cell module 101, a battery management system (BMS) 102, at least one expansion port 103, and a solar charging module 104. The cell module 101 is used for energy storage and can be, but is not limited to, lithium iron phosphate batteries, lithium manganese iron phosphate batteries, sodium batteries, etc. The battery management module 102 is the core management component of the energy storage system 100. The battery management module 102 is electrically connected to the cell module 101 to manage the charging and discharging of the cell module 101, ensuring its safe, efficient, and long-life operation. The battery management module 102 can also collect relevant parameters of the cell module 101, provide safety status estimation for the cell module 101, and implement communication and control functions. These relevant parameters may include, but are not limited to, voltage, current, ambient temperature, battery health status, and state of charge (SOC). The expansion port 103 serves as the interface for connecting the battery pack 10 to the outside world, enabling the transmission of electrical energy and communication. The solar charging module 104 can be electrically connected to the battery cell module 101 and the solar panel respectively, and is used to convert sunlight into DC power through the photovoltaic effect to charge the battery cell module 101.

[0038] The main pack may also include a control motherboard 105 and an inverter module 106. The control motherboard 105 is the control center of the energy storage system 100, responsible for coordinating the overall operating logic, integrating various sub-modules (such as sensors and displays), including the battery management module 102, and processing user commands and external signals to realize the overall function of the energy storage system 100. The control motherboard 105 can be electrically connected to the battery management module 102 of each battery pack 10. The inverter module 106 can be connected to the cell module 101, the solar charging module 104, the expansion port 103, and the battery management module 102 respectively. One end of the inverter module 106 can be electrically connected to each cell module 101, and the other end can be electrically connected to the expansion port 103 of the main pack. It is used to convert the DC power of the cell module 101 into AC power when the energy storage system 100 supplies power to external devices, or to convert the AC power input from the outside into DC power for input to the cell module 101 during charging.

[0039] When the main battery pack is not powered off, the control motherboard 105 can provide a preset voltage to each battery management module 102, which can be 5V. The presence of the preset voltage serves two purposes: firstly, it provides power to all isolated CAN communication signals; secondly, it acts as an activation signal for the control motherboard 105 to activate the battery management module 102. In other words, the presence of the preset voltage keeps the battery pack 10 in a charging and active state. At this time, the battery management module 102 cannot be powered off (it is in a pseudo-power-off state), and the battery management module 102 continuously consumes current, with power consumption generally between 10mA and 30mA.

[0040] Furthermore, the control motherboard 105 can also select one of the battery packs 10 as the target battery pack. The cell module 101 of the target battery pack can output power to the expansion port 103 through the inverter module 106 of the main pack to power the energy storage system 100 itself, ensuring that the control motherboard 105 can work normally. Specifically, after determining the target battery pack, the control motherboard 105 can send a control command to the battery management module 102 of the target battery pack, so that the battery management module 102 of the target battery pack controls the cell module 101 to conduct with the inverter module 106, and the inverter module 106 outputs the power of the cell module 101 to the expansion port 103 to power the energy storage system 100.

[0041] Understandably, in related technologies, the battery management module 102 of each battery pack 10 is typically powered by the cell modules 101 within the battery pack 10. If the battery management module 102 of the battery pack 10 continuously consumes power, it may cause the cell modules 101 to become depleted. However, in this application, the battery management module 102 is not only connected to the cell modules 101 but also to the expansion port 103. Since the expansion port 103 supplies power to the system, when the SOC of a battery pack 10 drops to 0, the expansion port 103 can still supply power to the battery management module 102, ensuring that the battery management module 102 can continue to operate even when a single battery pack 10 cannot supply power. At the same time, it avoids the battery management module 102 continuing to consume the cell modules 101, thus preventing depletion of power.

[0042] In some embodiments, each battery pack 10 further includes a first diode D1 and a second diode D2. The anode of the first diode D1 is connected to the expansion port 103, and the cathode of the first diode D1 is connected to the battery management module 102. The anode of the second diode D2 is connected to the anode of the cell module 101, and the cathode of the second diode D2 is connected to the battery management module 102. Due to the forward conduction and reverse cutoff characteristics of diodes, the first diode D1 prevents current from flowing to the expansion port 103 when the cell module 101 supplies power to the battery management module 102, and the second diode D2 prevents current from flowing to the cell module 101 when the expansion port 103 supplies power to the battery management module 102.

[0043] In this way, the battery pack 10, through the setting of diodes, perfectly implements the redundancy mechanism and automatic switching of dual power supply (local cell priority, bus power backup) of the battery management module 102 in a simple and reliable hardware manner without the need for additional control logic, and eliminates the potential interference risk between power paths, further strengthening the core capability of the system to maintain the operation of the battery management module 102 in abnormal conditions.

[0044] In some embodiments, each battery pack 10 also includes a resistor R, one end of which is connected to the expansion port 103, and the other end of which is connected to the battery management module 102.

[0045] Thus, by connecting a resistor R in series between the expansion port 103 and the battery management module 102, the maximum current in the circuit can be limited, thereby enabling the expansion port 103 to provide a stable current to the battery management module 102 and preventing short circuits / overloads.

[0046] In some embodiments, the control motherboard 105 includes a detection unit and a control unit, the detection unit being electrically connected to the control unit, the detection unit being configured to detect the ambient temperature; the control unit being configured to send a first control command to the battery management module 102 of the main pack when the ambient temperature is less than or equal to a preset temperature and the energy storage system 100 is connected to a solar panel, so that the main pack acts as the target battery pack to supply power to the energy storage system 100.

[0047] Specifically, the detection unit can be a temperature sensor, which can detect the ambient temperature in real time when the control motherboard 105 is not turned off and feed it back to the control unit. A preset temperature is used to determine whether the current environment is a low-temperature environment. When the ambient temperature is below the preset temperature, it can be determined to be a low-temperature environment. At this time, the solar panel cannot charge the cell module 101 of the battery pack 10. The preset temperature can be 0 degrees, 1 degree, 2 degrees, etc.

[0048] Understandably, due to battery characteristics, charging the energy storage system 100 in low-temperature environments can easily lead to lithium plating, posing a safety risk to the energy storage system 100. Therefore, when the ambient temperature is less than or equal to a preset temperature and the energy storage system 100 is connected to a solar panel, the control unit first enables the main battery pack to act as the target battery pack to supply power to the energy storage system 100. It then sends a first control command to the main battery pack's battery management module 102, causing the main battery pack's battery management module 102 to control the cell module 101 to output power to the inverter module 106, thus supplying power to the energy storage system 100. In this way, if other battery packs 10 have a SOC of 0, power can be supplied to the battery management module 102 of the battery pack 10 through the expansion port 103, preventing individual battery packs 10 from experiencing power depletion due to continuous power consumption by the battery management module 102.

[0049] In some implementations, the control unit is further configured to obtain the SOC of the expansion pack from the battery management module 102 of each expansion pack; if the SOC of the main pack is less than or equal to a preset threshold, a second control command is sequentially sent to the battery management module 102 of the expansion pack according to the SOC size of the expansion pack, so that the expansion pack is sequentially used as the target battery pack.

[0050] In this embodiment, the preset threshold can be equal to 0. That is, when the SOC of the main battery pack is less than or equal to 0, the second control command is sent sequentially to the battery management module 102 of the expansion pack according to the SOC size of the expansion pack, so that the expansion pack is used as the target battery pack in sequence. Of course, it is understood that the preset threshold can also be other values, such as 3%, 5%, 10%, 15%, 20%, etc., and there is no specific limitation.

[0051] Specifically, in low-temperature environments (such as below 0 degrees Celsius), when the solar panel is detected to be inserted into the solar charging module 104, the control unit can, when the SOC of the main battery pack drops to 0 or is about to drop to 0, obtain the SOC value of each expansion pack in its battery management module 102, compare the SOC values ​​of the expansion packs, and sort the expansion packs according to their SOC values. The expansion pack with the highest SOC value is prioritized as the target battery pack to supply power to the energy storage system 100. When the SOC of the expansion pack supplying power to the energy storage system 100 drops to a preset threshold, the expansion pack with the highest SOC value among the remaining expansion packs is selected as the target battery pack to supply power to the energy storage system 100, until the SOC of each expansion pack is depleted. Furthermore, the battery pack 10 with an SOC of 0 supplies power to the battery management module 102 via the expansion port 103 (system power supply).

[0052] For example, in some examples, battery pack 10 includes a main pack, expansion pack 1, expansion pack 2, expansion pack 3, expansion pack 4, and expansion pack 5. If the SOC1 of expansion pack 1 is 95%, the SOC2 of expansion pack 2 is 92%, the SOC3 of expansion pack 3 is 90%, the SOC4 of expansion pack 4 is 85%, and the SOC5 of expansion pack 5 is 70%, then in a low-temperature environment, when the solar panel is detected to be inserted into the solar charging module 104, the control unit can, when the SOC of the main pack drops to 0 or is about to drop to 0, prioritize expansion pack 1 as the target battery pack to power the energy storage system 100 itself, and provide a second control command to the battery management module 102 of expansion pack 1 to enable expansion pack 1 to power the system. When the SOC of expansion pack 1 drops to 0, the control unit provides a second control command to the battery management module 102 of expansion pack 2 to enable expansion pack 2 as the target battery pack to power the system. And when the SOC of expansion pack 2 drops to 0, a second control command is provided to the battery management module 102 of expansion pack 3 so that expansion pack 3 can be used as the target battery pack to supply power to the system; then when the SOC of expansion pack 3 drops to 0, a second control command is provided to the battery management module 102 of expansion pack 4 so that expansion pack 4 can be used as the target battery pack to supply power to the system; finally, when the SOC of expansion pack 4 drops to 0, a second control command is provided to the battery management module 102 of expansion pack 5 so that expansion pack 5 can be used as the target battery pack to supply power to the system.

[0053] This achieves an automatic and orderly transfer of system power supply responsibility. It ensures that when the main unit's power supply is insufficient due to power loss (such as insufficient PV charging on cloudy days or low-temperature protection), the expansion unit with the most remaining power can seamlessly continue supplying power to the load, significantly extending the continuous power supply time of the entire energy storage system 100 and preventing sudden power outages caused by the main unit's power loss. Simultaneously, the strategy of activating expansion units in descending order of State of Charge (SOC) prioritizes the use of the expansion units with the most abundant power, optimizing energy allocation efficiency and preventing the premature depletion of low-power expansion units, thus improving the overall availability of the energy storage system 100 under adverse conditions and enhancing the user's power supply guarantee capability.

[0054] In some embodiments, the control unit is also configured to initiate a power-loss prevention program when the SOC of each battery pack 10 is less than or equal to a preset threshold, thereby shutting down the energy storage system 100. After the power-loss prevention program is initiated, the control motherboard 105 is critically controlled to stop supplying a preset voltage to the battery management module 102, thereby shutting down the entire energy storage system.

[0055] Thus, the anti-discharge program is triggered when the charge of all battery packs 10 drops to or below a preset safety threshold, forcibly commanding the energy storage system 100 to shut down. This protects the battery packs 10 from deep discharge damage, effectively preventing irreversible damage caused by over-discharge, and greatly extending the overall lifespan and reliability of the battery packs 10. Simultaneously, this shutdown action is completed under the premise that the system control unit still has sufficient energy to operate its logic, ensuring that the shutdown process is controllable and safe, avoiding system instability due to complete depletion of power, and significantly improving the safety and long-term value of the energy storage system 100.

[0056] In some implementations, the control unit is also configured to send a start command to each battery management module 102 to power on the energy storage system 100 when the ambient temperature is higher than a preset temperature.

[0057] Thus, when the ambient temperature exceeds a preset safety threshold (e.g., above 0°C), a start-up command is automatically sent to the management modules of all battery packs 10, enabling the energy storage system 100 to intelligently start up. This effectively solves the problem that the energy storage system 100 remains in a shutdown state after the low-temperature protection is released, and cannot automatically resume power supply or charging. It also avoids the system remaining in a dormant state at suitable temperatures due to human forgetfulness or operational delays, significantly improving the system's response speed.

[0058] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An energy storage system, characterized by, The energy storage system includes multiple battery packs, which are divided into a main pack and at least one expansion pack. Both the main pack and the expansion pack include a cell module, a battery management module, and at least one expansion port. The main pack and the expansion pack are electrically connected through the expansion port. The main pack also includes a control motherboard electrically connected to the battery management module. The control motherboard is also electrically connected to the battery management module of each expansion pack through the expansion port. The control motherboard is configured to provide a preset voltage to the battery management module of each battery pack and select one of the battery packs as a target battery pack. The target battery pack can supply power to the energy storage system through the expansion port. The battery management module of each battery pack is electrically connected to the cell module and the expansion port, respectively, and the cell module or the expansion port can supply power to the battery management module.

2. The energy storage system of claim 1, wherein, Each of the battery packs also includes: The first diode has its positive terminal connected to the expansion port and its negative terminal connected to the battery management module; The second diode has its positive terminal connected to the positive terminal of the battery cell module and its negative terminal connected to the battery management module.

3. The energy storage system of claim 2, wherein, Each of the battery packs also includes: The resistor is connected at one end to the expansion port and at the other end to the battery management module.

4. The energy storage system of any one of claims 1-3, wherein, The control motherboard includes a detection unit and a control unit. The detection unit is electrically connected to the control unit, and the detection unit is configured to detect ambient temperature. The control unit is configured to: When the ambient temperature is less than or equal to a preset temperature and the energy storage system is connected to a solar panel, a first control command is sent to the battery management module of the main pack, so that the main pack acts as the target battery pack to supply power to the energy storage system.

5. The energy storage system of claim 4, wherein, The control unit is also configured to: Obtain the SOC of the expansion pack from the battery management module of each expansion pack; When the SOC of the main battery pack is less than or equal to a preset threshold, a second control command is sent sequentially to the battery management module of the expansion pack according to the SOC size of the expansion pack, so that the expansion pack is used as the target battery pack in sequence.

6. The energy storage system of claim 5, wherein, The control unit is also configured to: If the SOC of each battery pack is less than or equal to a preset threshold, a power loss prevention program is activated to shut down the energy storage system.

7. The energy storage system of claim 5, wherein, The control unit is also configured to: When the ambient temperature is higher than the preset temperature, a start command is sent to each of the battery management modules to power on the energy storage system.

8. The energy storage system of claim 1, wherein, The preset voltage is 5V.

9. The energy storage system of claim 1, wherein, The energy storage system also includes: An expansion bus connects the two expansion ports.

10. The energy storage system of claim 1, wherein, The energy storage system also includes: A solar charging module, one end of which is connected to the battery management module and the other end of which is connected to a solar panel, is used to convert sunlight into direct current electricity through the photovoltaic effect.

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