Energy storage system

Abstract

This invention provides an energy storage system, relating to the field of energy storage. The energy storage system includes an inverter device and multiple battery pack devices; each battery pack device includes at least a battery pack unit and a DC-DC converter; the inverter device sends charge / discharge signals to each battery pack device, and the battery pack devices, under the influence of the charge / discharge signals, charge and discharge the battery pack units via the DC-DC converters. This invention solves the problem of output current differences and circulating current issues caused by differences in electrical characteristics between battery pack units by connecting the DC-DC converters and battery pack units in series in each battery pack device. This avoids the deterioration of the electrical characteristics of the battery pack units, reduces the power range and voltage rating requirements of the DC-DC converters, lowers the circuit cost and power consumption of the energy storage system, and ensures the stability and reliability of the energy storage system during operation.

Description

Technical Field

[0001] This utility model relates to the field of energy storage, and more specifically, to an energy storage system. Background Technology

[0002] In energy storage systems, to increase the energy storage capacity, battery packs are typically connected in parallel to boost current output. However, this direct parallel connection of battery packs leads to differences in output current and circulating current between them due to differences in their electrical characteristics. Furthermore, this circulating current exacerbates the deterioration of the battery pack's electrical characteristics.

[0003] In existing technologies, a DC / DC optimizer can be connected in parallel at the output of each battery pack. The DC / DC optimizer adjusts the output current of each battery pack, allowing lower-performance battery packs to output smaller currents and higher-performance battery packs to output larger currents. This also avoids circulating currents between battery packs and extends the lifespan of the energy storage system.

[0004] However, this approach requires the power range of the DC / DC optimizer to match the power of the battery pack, and the voltage rating of the DC / DC optimizer to match the voltage rating of the battery pack. Therefore, it suffers from high power consumption and high circuit cost. Utility Model Content

[0005] The purpose of this invention is to provide an energy storage system that can reduce the power consumption and circuit cost of the energy storage system.

[0006] This utility model provides an energy storage system, including: an inverter device and multiple battery pack devices;

[0007] Each of the aforementioned battery pack devices includes at least: a battery pack unit and a DC-DC converter;

[0008] One end of the battery pack unit is connected in series with the first end of the DC-DC converter, and the other end of the battery pack unit is connected to the DC bus.

[0009] The first end of the inverter device is used to connect to the power grid, the second end of the inverter device is connected to the DC bus, and the DC bus is also connected to the second end of the DC converter in each of the battery pack devices;

[0010] The inverter device is used to send charge and discharge signals to each of the battery pack devices, and the battery pack devices are used to charge and discharge the battery pack units through the DC-DC converter under the action of the charge and discharge signals.

[0011] Optionally, the inverter device includes: an inverter control module, an inverter module, and a battery-side DC-DC converter module;

[0012] The first end of the inverter module is used to connect to the power grid, the second end of the inverter module is connected to the first end of the battery-side DC-DC converter module, and the second end of the battery-side DC-DC converter module is connected to the DC bus.

[0013] The first terminal of the inverter control module is connected to the third terminal of the inverter module, the second terminal of the inverter control module is connected to the third terminal of the battery-side DC-DC converter module, and the third terminal of the inverter control module is connected to each of the battery pack devices.

[0014] Optionally, each of the battery pack devices further includes: a battery pack control module and a switch module;

[0015] One end of the switching module is connected to the second end of the DC converter, and the other end of the switching module is connected to the DC bus.

[0016] The battery pack control module is connected to the inverter device, the battery pack unit, and the DC-DC converter;

[0017] The battery pack control module is used to control the switching module to turn on under the action of the charging and discharging signal, and to output a specified current through the battery pack unit and the DC-DC converter.

[0018] Optionally, the other end of the battery pack unit is connected to the negative terminal of the DC bus, the other end of the switch module is connected to the positive terminal of the DC bus, and the third terminal of the DC converter is connected to the negative terminal of the DC bus.

[0019] Optionally, the battery pack control module includes: a DC-DC converter control module and a battery management module;

[0020] The first terminal of the DC-DC converter control module is connected to the inverter device, and the second terminal of the DC-DC converter control module is connected to the third terminal of the DC-DC converter.

[0021] The DC-DC converter control module is used to control the switching module to turn on under the action of the charging and discharging signal, and to control the DC-DC converter to adjust the input or output current.

[0022] The first end of the battery management module is connected to the inverter device, and the second end of the battery management module is connected to the third end of the battery pack unit.

[0023] The battery management module is used to monitor the status information of the battery pack unit and send the status information of the battery pack unit to the inverter device.

[0024] Optionally, the switching module includes: a first NMOS transistor and a second NMOS transistor;

[0025] The drain of the first NMOS transistor is connected to the second terminal of the DC-DC converter, the source of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the source of the second NMOS transistor is connected to the DC bus.

[0026] Optionally, it may also include: photovoltaic panels;

[0027] The photovoltaic panel is connected to the fourth terminal of the inverter module.

[0028] Optionally, the inverter device further includes: a photovoltaic-side DC-DC conversion module;

[0029] The first terminal of the photovoltaic-side DC-DC converter module is connected to the fourth terminal of the inverter module, the second terminal of the photovoltaic-side DC-DC converter module is connected to the photovoltaic panel, and the third terminal of the photovoltaic-side DC-DC converter module is connected to the third terminal of the inverter control module.

[0030] Optionally, the photovoltaic-side DC-DC converter module includes a unidirectional DC-DC converter; the battery-side DC-DC converter module includes a bidirectional DC-DC converter.

[0031] Optionally, the inverter module is implemented based on any one of the following topologies: H4 topology, HERIC topology, three-level neutral clamp topology, and three-phase full-bridge topology.

[0032] The beneficial effects of the energy storage system provided by this utility model are as follows: by connecting the DC converter and the battery pack unit in series in each battery pack device, the output current difference and circulating current problem caused by the difference in electrical characteristics between battery pack units are solved, the deterioration of the electrical characteristics of the battery pack unit is avoided, and the power range requirements and withstand voltage level requirements of the DC converter are reduced. After connecting multiple battery pack devices including battery pack units and DC converters to the inverter device to form an energy storage system, the circuit cost and power consumption of the energy storage system can be reduced, and the stability and reliability of the energy storage system during operation can be guaranteed. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of the energy storage system provided in an embodiment of this utility model;

[0035] Figure 2A system control block diagram of an energy storage system provided in an embodiment of this utility model;

[0036] Figure 3 A schematic diagram of an inverter device in an energy storage system provided in an embodiment of this utility model;

[0037] Figure 4 A schematic diagram of the structure of each battery pack device in the energy storage system provided in the embodiment of this utility model;

[0038] Figure 5 Another structural schematic diagram of each battery pack device in the energy storage system provided in the embodiment of this utility model;

[0039] Figure 6 A schematic diagram of a battery pack control module in an energy storage system provided in an embodiment of this utility model;

[0040] Figure 7 A schematic diagram of a switching module in an energy storage system provided in this embodiment of the utility model;

[0041] Figure 8 Another structural schematic diagram of the inverter device in the energy storage system provided in this embodiment of the utility model;

[0042] Figure 9 This is another structural schematic diagram of the inverter device in the energy storage system provided in the embodiment of this utility model. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0047] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0048] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0049] In existing technologies, a DC / DC optimizer can be connected in parallel at the output of each battery pack. The DC / DC optimizer adjusts the output current of each battery pack, allowing lower-performance battery packs to output smaller currents and higher-performance battery packs to output larger currents. This also avoids circulating currents between battery packs and extends the lifespan of the energy storage system.

[0050] However, this approach requires the power range of the DC / DC optimizer to match the power of the battery pack, and the voltage rating of the DC / DC optimizer to match the voltage rating of the battery pack. Therefore, it suffers from high power consumption and high circuit cost.

[0051] Based on the above-mentioned problems, this utility model proposes an energy storage system. By adopting a series connection of battery pack units and DC-DC converters, the power range requirements and withstand voltage requirements of the DC-DC converters can be reduced. After connecting multiple battery pack devices, including battery pack units and DC-DC converters, to an inverter device to form an energy storage system, the circuit cost of the energy storage system can be reduced, and the power consumption of the energy storage system can be reduced.

[0052] Figure 1 Please refer to the structural schematic diagram of an energy storage system provided in an embodiment of this utility model. Figure 1This embodiment provides an energy storage system, including an inverter device and multiple battery pack devices.

[0053] Each battery pack assembly includes at least: a battery pack unit and a DC-DC converter.

[0054] Optionally, the DC-DC converter can be an isolated DC-DC converter.

[0055] One end of the battery pack unit is connected in series with the first end of the DC-DC converter, and the other end of the battery pack unit is connected to the DC bus; the first end of the inverter device is used to connect to the power grid, the second end of the inverter device is connected to the DC bus, and the DC bus is also connected to the second end of the DC-DC converter in each battery pack device.

[0056] Optionally, Figure 1 Taking two battery pack devices as an example, when there are multiple battery pack devices in the energy storage system, the multiple battery pack devices can be stacked to reduce the volume occupied.

[0057] Optionally, the first end of the inverter device can also be used to connect to an external load, so that each battery pack device can charge and discharge to the external load.

[0058] Optionally, the inverter device can also be connected to each battery pack device for communication, so that the inverter device can send charging and discharging signals to each battery pack device.

[0059] The inverter device is used to send charge and discharge signals to each battery pack device, and the battery pack device is used to charge and discharge the battery pack units through the DC-DC converter under the action of the charge and discharge signals.

[0060] Optionally, the inverter device is used to simultaneously send charge and discharge signals to each battery pack device, and the battery pack unit in each battery pack device is used to charge and discharge the battery pack unit through the DC-DC converter under the action of the charge and discharge signal, so as to ensure the common DC bus voltage balance of each battery pack device.

[0061] Optionally, the battery pack units in each battery pack assembly, along with the DC converter and the DC bus, form a charging and discharging circuit, so that the battery pack units in each battery pack assembly can charge and discharge to the power grid or external load through the DC bus under the control of the DC converter.

[0062] The connection between the battery pack unit and the DC converter, as well as the connection between the battery pack unit and the DC bus, are all made by electrical connection, so that electrical signals such as sampling signals and drive signals can be transmitted.

[0063] For example, Figure 2 A system control block diagram of an energy storage system provided in an embodiment of this utility model, with reference to Figure 2As shown, this invention can also be configured according to the order in which the battery packs are arranged in the energy storage system. The first battery pack in each battery pack can be designated as the main battery pack. The main battery pack then houses one backup battery pack and multiple slave battery packs among the remaining battery packs. The main battery pack receives the total current demand from the inverter and, based on the total circuit demand, the state of charge of the backup battery pack, and the state of charge of each slave battery pack, distributes current to all battery packs and controls the DC bus voltage. The backup battery pack and the multiple slave battery packs charge and discharge according to the current distributed by the main battery pack.

[0064] For example, continue to refer to Figure 2 As shown, each battery pack unit may also include a current setting calculation unit and an operating unit. UnitN represents the Nth battery pack unit in the energy storage system, Pack N SOX represents the state of charge of the battery pack unit in the Nth battery pack unit, and the UnitN current controller is the DC-DC converter in the Nth battery pack unit.

[0065] In this embodiment, by connecting the DC-DC converter and the battery pack unit in series in each battery pack device, the output current difference and circulating current problem caused by the difference in electrical characteristics between battery pack units are solved, the deterioration of the electrical characteristics of the battery pack unit is avoided, and the power range requirements and withstand voltage requirements of the DC-DC converter are reduced. After connecting multiple battery pack devices including battery pack units and DC-DC converters to the inverter device to form an energy storage system, the circuit cost and power consumption of the energy storage system can be reduced, and the stability and reliability of the energy storage system during operation can be guaranteed.

[0066] Figure 3 This is a schematic diagram of an inverter device in an energy storage system provided by an embodiment of the present invention.

[0067] As an optional implementation method, refer to Figure 3 As shown, in Figure 1 Based on this, the inverter device includes: an inverter control module, an inverter module, and a battery-side DC-DC conversion module.

[0068] The first end of the inverter module is used to connect to the power grid, the second end of the inverter module is connected to the first end of the battery-side DC-DC converter module, and the second end of the battery-side DC-DC converter module is connected to the DC bus.

[0069] The first terminal of the inverter control module is connected to the third terminal of the inverter module, the second terminal of the inverter control module is connected to the third terminal of the battery-side DC-DC converter module, and the third terminal of the inverter control module is connected to each battery pack device.

[0070] Optionally, the inverter module includes a bidirectional DC / AC converter (referred to as bidirectional DC / AC) for converting electrical energy into AC and DC, realizing bidirectional conversion of electrical energy form. Specifically, it converts the electrical energy input from the power grid from AC to DC, or converts the electrical energy output to the power grid and external loads from DC to AC.

[0071] Optionally, the inverter control module includes a main control module and a battery management system (BMS). The main control module is used to send charging and discharging signals to each battery pack device, control the power conversion of the inverter module, and protect the inverter device. The BMS is used to interact with the BMU in each battery pack device to monitor and manage the status of the battery pack units in each battery pack device.

[0072] Optionally, the battery-side DC-DC converter module includes a DC-DC converter (DCDC) for voltage regulation and matching of DC power, thereby enabling the charging and discharging of the energy storage system.

[0073] The inverter control module is communicatively connected to each battery pack, electrically connected to the inverter, and electrically connected to the battery-side DC-DC converter module.

[0074] By incorporating an inverter control module, an inverter module, and a battery-side DC-DC converter module into the inverter device, energy exchange between the grid and each battery pack can be achieved through the inverter module and the battery-side DC-DC converter module. At the same time, the inverter control module can control the energy exchange process between the grid and each battery pack, enabling the energy storage system to achieve more efficient and stable power conversion and grid-connected power generation.

[0075] Figure 4 This is a schematic diagram of the structure of each battery pack device in the energy storage system provided in the embodiment of this utility model.

[0076] As an optional implementation method, refer to Figure 4 As shown, in Figure 1 In addition to the above, each battery pack device also includes: a battery pack control module and a switch module.

[0077] One end of the switching module is connected to the second end of the DC-DC converter, and the other end of the switching module is connected to the DC bus. The battery pack control module is connected to the inverter device, the battery pack unit, and the DC-DC converter.

[0078] Optionally, the switching module may include power semiconductor devices and switching devices such as relays, for controlling the conduction and cutoff of the battery pack units in each battery pack device and the charging and discharging circuit formed by the DC converter and DC bus.

[0079] The battery pack control module is used to control the switching module to turn on under the action of charging and discharging signals, and to output a specified current through the battery pack unit and DC-DC converter.

[0080] Optionally, the battery pack control module is used to control the switching module to turn on under the action of the charging and discharging signal, and to control the DC-DC converter to output a specified current through the battery pack unit and the DC-DC converter.

[0081] The inverter unit is communicatively connected to each battery pack control module, and the battery pack control module is electrically connected to the DC converter and the battery pack unit.

[0082] By incorporating a switch module into the battery pack and controlling its on / off state through a battery pack control module, the battery pack can be connected to or disconnected from the energy storage system based on actual conditions, thereby improving the stability and reliability of the energy storage system.

[0083] As an optional implementation method, Figure 5 This is another structural schematic diagram of the battery pack devices in the energy storage system provided by the embodiments of this utility model, with reference to... Figure 5 As shown, in Figure 4 Based on this, the other end of the battery pack unit is connected to the negative terminal of the DC bus, the other end of the switch module is connected to the positive terminal of the DC bus, and the third terminal of the DC converter is connected to the negative terminal of the DC bus.

[0084] Alternatively, connecting the other end of the battery pack unit to the negative terminal of the DC bus and connecting the third terminal of the DC converter to the negative terminal of the DC bus can help manage and protect the battery pack unit and extend its service life.

[0085] Optionally, connecting the other end of the switching module to the positive terminal of the DC bus enables the on / off control of the power supply to the battery pack, ensuring normal power supply when needed and safe power disconnection when not needed. It also provides overcurrent and overvoltage protection functions, and can quickly cut off the power supply when the energy storage system malfunctions, protecting other equipment and components in the energy storage system from damage.

[0086] As an optional implementation method, Figure 6 A schematic diagram of a battery pack control module in an energy storage system provided by this utility model embodiment, with reference to... Figure 6 As shown, in Figure 4 Based on this, the battery pack control module includes: a DC-DC converter control module and a battery management unit (BMU).

[0087] The first terminal of the DC-DC converter control module is connected to the inverter device, and the second terminal of the DC-DC converter control module is connected to the third terminal of the DC-DC converter.

[0088] The DC-DC converter control module is used to control the switching module to turn on under the action of charging and discharging signals, and to control the DC-DC converter to adjust the input or output current.

[0089] The first end of the battery management module is connected to the inverter device, and the second end of the battery management module is connected to the third end of the battery pack unit.

[0090] The battery management module is used to monitor the status information of the battery pack units and send the status information of the battery pack units to the inverter device.

[0091] Optionally, the DC-DC converter control module can receive the charging and discharging signals sent by the inverter device, and under the action of the charging and discharging signals, control the switching module to turn on, and control the DC-DC converter to adjust the input or output current.

[0092] For example, after receiving a charge / discharge signal, the DC-DC converter control module controls the switch module to turn on and controls the DC-DC converter to adjust the input or output current according to the current allocated by the main battery pack device, thereby outputting a specified current.

[0093] The inverter unit is communicatively connected to the DC-DC converter control module, the inverter unit is communicatively connected to the BMU, the DC-DC converter control module is electrically connected to the DC-DC converter, and the BMU is electrically connected to the battery pack unit.

[0094] Optionally, the battery management module monitors and processes the status information of the battery pack units in real time, thereby achieving comprehensive monitoring and protection of the battery pack units, such as overcharge protection, over-discharge protection, short circuit protection, and temperature protection. The status information includes key parameters such as the voltage, internal resistance, and temperature of each individual battery cell.

[0095] Optionally, the battery management module can also send the status information of the battery pack units to the battery management system in the inverter device, so that the inverter device can send different charging and discharging signals to the battery pack units in different states.

[0096] As an optional implementation method, Figure 7 This is a schematic diagram of a switching module in an energy storage system provided by an embodiment of the present invention, with reference to... Figure 7 As shown, in Figure 4 Based on this, the switching module includes: a first NMOS transistor Q1 and a second NMOS transistor Q2.

[0097] The drain of the first NMOS transistor Q1 is connected to the second terminal of the DC-DC converter, the source of the first NMOS transistor Q1 is connected to the drain of the second NMOS transistor Q2, and the source of the second NMOS transistor Q2 is connected to the DC bus.

[0098] By setting a first NMOS transistor and a second NMOS transistor in the switching module, the switching module can be turned on or off by controlling the gate voltage of the first NMOS transistor and the gate voltage of the second NMOS transistor. This reduces the design cost of the circuit. At the same time, when the output voltage of the DC-DC converter is too high or the current is too large, the current flow can be limited by controlling the gate voltage of Q1 and Q2, thereby protecting other components in the circuit from damage.

[0099] As an optional implementation method, Figure 8 This is another structural schematic diagram of the inverter device in the energy storage system provided by the present invention, referring to... Figure 8 As shown, in Figure 3 In addition to the above, energy storage systems also include: photovoltaic panels.

[0100] The photovoltaic panel is connected to the fourth terminal of the inverter module.

[0101] The photovoltaic panel is electrically connected to the fourth terminal of the inverter module.

[0102] Optionally, the photovoltaic panels can be connected to the fourth terminal of the inverter module via a DC combiner box. The DC power generated by the photovoltaic panels can be connected to the DC combiner box in series or parallel, and then transmitted from the combiner box to the inverter module via a DC cable.

[0103] The energy storage system provided by this utility model can be a photovoltaic energy storage system. After the photovoltaic panel is connected to the inverter device, the inverter device can efficiently convert the DC power generated by the photovoltaic panel into AC power, thereby improving the energy utilization rate.

[0104] As an optional implementation method, Figure 9 This is another structural schematic diagram of the inverter device in the energy storage system provided by the present invention, referring to... Figure 9 As shown, in Figure 8 In addition to the above, the inverter device also includes: a photovoltaic-side DC-DC conversion module.

[0105] The first terminal of the photovoltaic-side DC-DC converter module is connected to the fourth terminal of the inverter module, the second terminal of the photovoltaic-side DC-DC converter module is connected to the photovoltaic panel, and the third terminal of the photovoltaic-side DC-DC converter module is connected to the third terminal of the inverter control module.

[0106] The photovoltaic-side DC-DC converter module is electrically connected to the fourth terminal of the inverter module, and the third terminal of the photovoltaic-side DC-DC converter module is electrically connected to the third terminal of the inverter control module.

[0107] Optionally, the photovoltaic panel can be connected to the second terminal of the photovoltaic-side DC-DC converter module via a DC combiner box. The DC power generated by the photovoltaic panel can be connected to the DC combiner box in series or parallel, and then transmitted from the DC combiner box to the photovoltaic-side DC-DC converter module, so that the photovoltaic-side DC-DC converter module can convert the input DC power and deliver the electrical energy to each battery pack device or the power grid.

[0108] As an optional implementation, the photovoltaic-side DC-DC converter module includes a unidirectional DC-DC converter; the battery-side DC-DC converter module includes a bidirectional DC-DC converter.

[0109] Optionally, the photovoltaic-side DC-DC conversion module includes a unidirectional DC-DC converter (abbreviated as unidirectional DC-DC converter) for unidirectional DC-DC conversion of the electrical energy input from the photovoltaic panel.

[0110] Optionally, the battery-side DC-DC converter module includes a bidirectional DC-DC converter (hereinafter referred to as bidirectional DC / DC) for bidirectional DC-DC conversion of electrical energy.

[0111] Optionally, the unidirectional DC converter in the photovoltaic-side DC-DC conversion module can be implemented based on the BOOST circuit, and can be connected to one or more photovoltaic panels according to power requirements.

[0112] Optionally, the bidirectional DC-DC converter in the battery-side DC-DC converter module can be implemented based on a BOOST circuit, thereby enabling battery charging or discharging through bidirectional energy flow.

[0113] Optionally, the bidirectional DC-AC converter in the inverter module can be implemented based on any of the following topologies: H4 topology, HERIC topology, three-level neutral clamp (NPC) topology, and three-phase full-bridge topology, thereby realizing bidirectional energy flow.

[0114] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An energy storage system, characterized by, include: Inverter unit and multiple battery pack units; Each of the aforementioned battery pack devices includes at least: a battery pack unit and a DC-DC converter; One end of the battery pack unit is connected in series with the first end of the DC-DC converter, and the other end of the battery pack unit is connected to the DC bus. The first end of the inverter device is used to connect to the power grid, the second end of the inverter device is connected to the DC bus, and the DC bus is also connected to the second end of the DC converter in each of the battery pack devices; The inverter device is used to send charge and discharge signals to each of the battery pack devices, and the battery pack devices are used to charge and discharge the battery pack units through the DC-DC converter under the action of the charge and discharge signals. Each of the aforementioned battery pack devices further includes: a battery pack control module and a switch module; One end of the switching module is connected to the second end of the DC converter, and the other end of the switching module is connected to the DC bus. The battery pack control module is connected to the inverter device, the battery pack unit, and the DC-DC converter; The battery pack control module is used to control the switch module to turn on under the action of the charging and discharging signal, and to output a specified current through the battery pack unit and the DC-DC converter; The other end of the battery pack unit is connected to the negative terminal of the DC bus, the other end of the switch module is connected to the positive terminal of the DC bus, and the third end of the DC converter is connected to the negative terminal of the DC bus.

2. The energy storage system according to claim 1, characterized in that, The inverter device includes: an inverter control module, an inverter module, and a battery-side DC-DC converter module; The first end of the inverter module is used to connect to the power grid, the second end of the inverter module is connected to the first end of the battery-side DC-DC converter module, and the second end of the battery-side DC-DC converter module is connected to the DC bus. The first terminal of the inverter control module is connected to the third terminal of the inverter module, the second terminal of the inverter control module is connected to the third terminal of the battery-side DC-DC converter module, and the third terminal of the inverter control module is connected to each of the battery pack devices.

3. The energy storage system according to claim 1, characterized in that, The battery pack control module includes: a DC-DC converter control module and a battery management module; The first terminal of the DC-DC converter control module is connected to the inverter device, and the second terminal of the DC-DC converter control module is connected to the third terminal of the DC-DC converter. The DC-DC converter control module is used to control the switching module to turn on under the action of the charging and discharging signal, and to control the DC-DC converter to adjust the input or output current. The first end of the battery management module is connected to the inverter device, and the second end of the battery management module is connected to the third end of the battery pack unit. The battery management module is used to monitor the status information of the battery pack unit and send the status information of the battery pack unit to the inverter device.

4. The energy storage system according to claim 1, characterized in that, The switching module includes: a first NMOS transistor and a second NMOS transistor; The drain of the first NMOS transistor is connected to the second terminal of the DC-DC converter, the source of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the source of the second NMOS transistor is connected to the DC bus.

5. The energy storage system according to claim 2, characterized in that, Also includes: Photovoltaic panels; The photovoltaic panel is connected to the fourth terminal of the inverter module.

6. The energy storage system according to claim 5, characterized in that, The inverter device further includes: a photovoltaic-side DC-DC conversion module; The first terminal of the photovoltaic-side DC-DC converter module is connected to the fourth terminal of the inverter module, the second terminal of the photovoltaic-side DC-DC converter module is connected to the photovoltaic panel, and the third terminal of the photovoltaic-side DC-DC converter module is connected to the third terminal of the inverter control module.

7. The energy storage system according to claim 6, characterized in that, The photovoltaic-side DC-DC converter module includes a unidirectional DC-DC converter; the battery-side DC-DC converter module includes a bidirectional DC-DC converter.

8. The energy storage system according to claim 7, characterized in that, The inverter module is implemented based on any one of the following topologies: H4 topology, HERIC topology, three-level neutral clamping topology, and three-phase full-bridge topology.

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