energy storage device

Abstract

The application relates to an energy storage device, belonging to the technical field of energy storage. The energy storage device comprises a container, a plurality of battery packs, a plurality of converters and a power distribution cabinet, the container comprises a battery cabin and an electrical cabin; the plurality of battery packs are arranged in the battery cabin in series into clusters, the direct current side of each converter is electrically connected with at least one battery cluster, and the alternating current side of the plurality of converters is electrically connected with the power distribution cabinet. In the application, a single converter can monitor and control a smaller number of battery clusters, the control precision can be improved, the circulating current problem of traditional centralized converters can be optimized, and the energy efficiency of the energy storage system can be improved.

Description

Technical Field

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

[0002] Energy storage equipment is a modular integrated energy storage system that typically integrates batteries, battery management systems, energy conversion systems, thermal management systems, fire protection facilities, etc., into standard or non-standard containers. Therefore, energy storage equipment is also called energy storage container.

[0003] Current energy storage devices are typically used as auxiliary units of power plants, operating in parallel with the power plant through a grid interface. When there is excess power in the power plant, the excess power is stored in the energy storage device. When there is insufficient power in the power plant, the energy storage device transmits the stored power to the power plant, which then distributes it to the load.

[0004] It is evident that most energy storage devices currently cannot directly supply power to the load. In order to directly supply power to the load, an additional isolation transformer is required, which results in low application flexibility of energy storage devices. Utility Model Content

[0005] To address the problems of existing technologies, this application provides an energy storage device. The technical solution is as follows:

[0006] The energy storage device includes a container, multiple battery packs, multiple converters, and a power distribution cabinet. The container includes a battery compartment and an electrical compartment.

[0007] The multiple battery packs are connected in series and arranged in a cluster in the battery compartment. The DC side of each converter is electrically connected to at least one battery cluster, and the AC side of the multiple converters is electrically connected to the power distribution cabinet.

[0008] Optionally, the rated voltage output of each battery cluster is less than or equal to 1000V.

[0009] Optionally, the DC side of each converter is electrically connected to a battery cluster.

[0010] Optionally, each converter is a three-phase four-wire converter, and the AC side interface of the converter is a three-phase four-wire interface.

[0011] Optionally, each converter integrates a high-voltage box function for providing electrical isolation, short-circuit protection, and pre-charge management between the electrically connected converter and the battery cluster.

[0012] Alternatively, each converter is positioned on top of the connected battery cluster.

[0013] Optionally, each battery cluster includes five battery packs, and the five battery packs of each battery cluster are stacked in the height direction of the container.

[0014] Optionally, the panel of the distribution cabinet has quick-connect interfaces for connecting to the power grid and quick-connect interfaces for connecting to the load.

[0015] Optionally, the door of the electrical compartment has an opening at the location of the corresponding quick-connect connector for cables to pass through.

[0016] Optionally, the energy storage device further includes a charging pile, which is arranged in the electrical compartment and electrically connected to the power distribution cabinet. The charging gun of the charging pile is used to charge electric vehicles.

[0017] Optionally, the fire protection system of the energy storage device is a non-piped fire protection system, which includes multiple fire extinguishing devices and multiple fire detectors, wherein the multiple fire extinguishing devices and multiple fire detectors are all arranged inside the battery compartment.

[0018] Optionally, the fire detector includes a smoke detector, a temperature detector, and a combustible gas detector.

[0019] Optionally, the fire extinguishing device is a non-pressurized gas fire extinguishing device, and the fire extinguishing device is arranged above the battery cluster.

[0020] Optionally, a water spray assembly is also arranged inside the battery compartment and at its top, wherein the water spray assembly includes a water pipe and a spray head mounted on the water pipe.

[0021] Optionally, the noise level at a distance of one meter from the container is less than or equal to 65 dB.

[0022] Optionally, the container is a 20-foot flat rack container.

[0023] The beneficial effects of the technical solution provided in this application are:

[0024] In this application, the energy storage device includes multiple converters, each of which is electrically connected to one or more battery clusters; for example, one converter is electrically connected to one battery cluster. Compared to connecting all battery clusters in series with a single converter, this approach allows a single converter to monitor and control a smaller number of battery clusters, resulting in higher control accuracy. It also optimizes the circulating current problem of traditional centralized converters, thereby improving the energy efficiency of the energy storage system.

[0025] In addition, the rated voltage of the DC power output by the battery clusters in the energy storage device does not exceed 1000V, which enables the converter in the energy storage device to directly convert the DC power into a low voltage that the load can use. This allows the energy storage device to be used in an off-grid state without the need for an additional isolation transformer, thus improving the application flexibility of the energy storage device.

[0026] In this application, the interfaces for connecting to the power grid and the interfaces for connecting to the load are both arranged on the panel of the distribution cabinet to facilitate operation by the staff. Moreover, these electrical interfaces are all quick-connect interfaces to achieve plug-and-play functionality. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a front view schematic diagram of an energy storage device provided in an exemplary embodiment of this application;

[0029] Figure 2 This is a top view schematic diagram of an energy storage device provided in an exemplary embodiment of this application.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Container; 11. Lifting structure; 2. Battery pack; 20. Battery cluster; 3. Converter; 31. AC side interface; 32. DC side interface; 4. Distribution cabinet; 5. Fire extinguishing device; 6. Liquid cooling unit; 7. Water spray assembly. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0033] This embodiment relates to an energy storage device, which is used to store, convert, manage and safely operate electrical energy. It is usually integrated in a standard or non-standard container, hence also called an energy storage container. It has a high degree of integration and modularity, which facilitates transportation and installation.

[0034] While current energy storage devices are mobile, their mobility is primarily for ease of transport; once installed, they are rarely moved. Current energy storage devices are generally connected to power plants (also known as power grids, such as municipal power grids). For example, the energy storage device is installed near a power plant, with its bottom wiring connected to the power plant. When the power plant has surplus energy, it transfers the excess energy to the energy storage device for storage. When the power plant's energy is insufficient, the energy storage device transfers the stored energy back to the power plant, which then distributes it to the load.

[0035] It is evident that once installed, current energy storage devices are almost immobile, limiting their application scenarios and application flexibility.

[0036] Moreover, most current energy storage devices operate in tandem with power plants and cannot operate off-grid. If energy storage devices need to operate off-grid, they also need to be equipped with an isolation transformer to convert the high voltage output of the energy storage device into the low voltage required by the load (such as 380V). The additional isolation transformer increases the weight and size of the energy storage device.

[0037] This embodiment provides an energy storage device that can operate off-grid without the need for an additional isolation transformer to directly power loads. Therefore, the energy storage device can function as a large mobile power source, moving to the vicinity of a power station for charging and to any load scenario requiring charging for discharging. The energy storage device offers high application flexibility.

[0038] like Figure 1 and Figure 2 The image shown is a schematic diagram of the energy storage device. Figure 1 The image shows the main view of the energy storage device. Figure 2 A top view of the energy storage device is shown.

[0039] Energy storage equipment mainly includes battery systems, power conversion systems, thermal management systems, fire protection systems, power distribution and management systems, and monitoring and energy management systems, all integrated into a single container.

[0040] In one example, the container for the energy storage equipment can be a 20-foot flat rack container with dimensions of 6058 mm (length), 2438 mm (width), and 2591 mm (height). The fans and pressure relief vents on the top of the container can be integrated into the interior, creating a seamless, protruding design to facilitate the movement and transportation of the energy storage equipment.

[0041] In a battery system, the cell is the most basic and smallest unit, and a single cell typically provides a voltage between 3V and 4V. For ease of management, multiple cells are usually connected in series or parallel and then placed in a frame to form a battery module. Multiple battery modules connected in series or parallel, along with a battery management system (BMS) to manage battery temperature, voltage, etc., together form a battery pack.

[0042] Battery packs are typically arranged in clusters within the container of an energy storage device. For example, see reference... Figure 1 and Figure 2 As shown, the space inside a container is generally divided into a battery compartment and an electrical compartment. Multiple battery packs 2 are stacked in the height direction into a cluster (denoted as a battery cluster 20) and arranged in the battery compartment. For example, see reference... Figure 1As shown, a battery cluster 20 consists of five battery packs 2 stacked in the height direction.

[0043] refer to Figure 1 and Figure 2 As shown, multiple battery clusters 20 are arranged in the battery compartment of the container. For example, multiple battery clusters 20 are arranged along the left-right width direction of the battery compartment, and multiple battery clusters 20 are arranged along the front-back depth direction of the battery compartment. For example, refer to Figure 2 As shown, there are five battery clusters 20 arranged in the left and right width direction of the battery compartment, and two battery clusters 20 arranged in the front and back depth direction, for a total of ten battery clusters 20.

[0044] In one example, multiple battery clusters 20 can be connected in parallel or in series; this embodiment uses a parallel connection as an example. Multiple battery packs 2 within a single battery cluster 20 can be connected in series or in parallel; this embodiment uses a series connection as an example.

[0045] In this embodiment, the energy storage device has a relatively low maximum DC voltage, which is also its rated power voltage. The power conversion system (PCS) can directly convert this voltage into low-voltage AC power to supply the load. For example, if the rated DC voltage of the energy storage device is less than or equal to 1000V, the PCS can directly convert 1000V DC voltage into 380V AC power without the need for an isolation transformer. Single-stage power conversion, compared to multi-stage conversion, also reduces energy losses during power conversion.

[0046] In one example, to ensure that the rated voltage of the energy storage device on the DC side does not exceed 1000V, in a scheme where multiple battery clusters 20 are connected in parallel, the rated voltage of the DC output from each battery cluster 20 does not exceed 1000V. Based on multiple battery packs 2 connected in series within a single battery cluster 20, and multiple cells connected in series within a single battery pack 2, with the voltage of a single cell between 3V and 4V, the number of cells in a single battery cluster 20 is less than or equal to 260. Thus, the rated voltage of a single battery cluster will not exceed 1000V.

[0047] The power conversion system of an energy storage device mainly refers to a power conversion system (PCS), which is used to convert alternating current (AC) to direct current (DC) during the charging of the energy storage device so that the DC current can be stored in the battery. During the discharging of the energy storage device, the DC current output from the battery is converted back to alternating current.

[0048] refer to Figure 1 and Figure 2As shown, the converter 3 in this embodiment is specifically a string converter to achieve one-cluster-one-management, with each battery cluster 20 electrically connected to one converter 3. Therefore, the energy storage device includes multiple converters 3, and multiple battery clusters 20 correspond one-to-one with and are electrically connected to multiple converters 3. Specifically, the electrical connection between the battery cluster 20 and the converter 3 means that the battery cluster 20 is electrically connected to the DC side of the converter 3. All converters 3 are connected in parallel to the distribution cabinet 4 of the energy storage device. That is, the AC side of all converters 3 is electrically connected to the distribution cabinet 4.

[0049] This type of battery cluster 20 is electrically connected to a converter 3. Compared to multiple battery clusters 20 being electrically connected to a single converter (which is a centralized converter), each battery cluster 20 can be independently monitored and controlled. Compared to a centralized converter, the string converter has higher control precision and can also optimize the circulating current problem of traditional centralized converters, thereby improving the energy efficiency of the energy storage system.

[0050] Continue to refer to Figure 1 and Figure 2 As shown, each inverter 3 is arranged on top of a cluster of batteries 20 that is electrically connected, that is, the inverter 3 is arranged on top of the uppermost battery pack in a cluster of batteries 20. This battery compartment contains only five battery packs and one inverter in the height direction, which helps to reduce the height of the energy storage device, thereby lowering the center of gravity of the energy storage device and improving the stability of the energy storage device. Therefore, the energy storage device is more stable when moving.

[0051] In another example, each of the multiple converters 3 can also be electrically connected to multiple battery clusters 20. For instance, one converter 3 can be electrically connected to two battery clusters 20, which are connected in series to the DC side of the same converter 3. This connection of multiple battery clusters 20 to multiple converters 3, compared to connecting all battery clusters 20 to a single converter 3, also offers higher control precision, optimizes circulating current issues, and improves the energy efficiency of the energy storage system.

[0052] In one example, the converter 3 not only has AC / DC bidirectional conversion function, but also integrates a high-voltage box function, which is used for electrical isolation, short-circuit protection and pre-charge management between the electrically connected converter and battery cluster.

[0053] For example, converter 3 integrates a high-voltage disconnect switch, fuses, a pre-charge module, and a DC contactor. The high-voltage disconnect switch provides physical isolation between the battery pack and the converter, while the fuse provides short-circuit protection, quickly cutting off fault current in the event of a short circuit within the battery pack. The pre-charge module is used to prevent inrush current.

[0054] The converter integrates a high-voltage box function, which can eliminate the need for a high-voltage box, reduce the space occupied by the high-voltage box in the container, improve the integration level of energy storage equipment, and simplify the electrical connection between the battery cluster and the converter.

[0055] Since energy storage devices can directly supply electrical energy to the load, to improve safety, the converter can be a three-phase four-wire converter, as shown in the reference. Figure 1 As shown, the AC side interface 31 of each converter is specifically a three-phase four-wire interface, which includes L1 port, L2 port, L3 port, and N port. (Continue to refer to...) Figure 1 As shown, each converter 3 has a DC-side interface 32 with a positive port and a negative port. The DC-side interface 32 is used to connect to the battery pack, and the AC-side interface is used to connect to the distribution cabinet.

[0056] The power distribution and management system for energy storage devices mainly refers to the distribution cabinet. (See reference...) Figure 1 and Figure 2 As shown, the distribution cabinet 4 is located in the electrical compartment. The distribution cabinet 4 is electrically connected to the AC side of the converter 3. The panel of the distribution cabinet 4 has quick-connect interfaces for connecting to the power grid and quick-connect interfaces for connecting to the load. The quick-connect interfaces are also interfaces that can be plugged into and plugged into electrical connection connectors, enabling the energy storage device to be used immediately upon connection.

[0057] When the energy storage device needs to be charged, it can be plugged into the power grid through the charging quick-connect interface. When the energy storage device is discharging, it can be plugged into the load through the discharging quick-connect interface.

[0058] Compared to traditional energy storage devices that connect to the power grid at the bottom, this embodiment places the interface for grid connection on the panel of the distribution cabinet, making it easier for staff to operate. The interface for grid connection is a quick-connect interface, which makes charging easier.

[0059] In one example, the door of the electrical compartment containing the distribution cabinet can be designed with a window to facilitate connection to the load. For instance, the door of the electrical compartment may have a window at the location of the quick-connect interface, allowing cables plugged into the quick-connect interface to pass through.

[0060] In one example, the energy storage device may also include a charging station for charging electric vehicles. The charging station may be located in an electrical compartment and is electrically connected to a power distribution cabinet. The charging station's charging gun is used to charge the electric vehicle.

[0061] In one application scenario, when an electric vehicle has low or no battery power, the energy storage device can be moved to the location of the electric vehicle and charged using the energy storage device's charging station.

[0062] Fire suppression systems for energy storage devices can be non-piped fire suppression systems, also known as prefabricated fire extinguishing systems or non-piped fire extinguishing systems. These are fire suppression solutions tailored to the characteristics of battery fires. Their core feature is the elimination of complex piping networks; through modular design, fire suppression devices are directly deployed near battery clusters or energy storage cabinets, achieving rapid response and precise fire suppression.

[0063] Therefore, the energy storage device can include multiple fire extinguishing devices and multiple fire detectors, with the multiple fire extinguishing devices evenly distributed in the battery compartment and the multiple fire detectors also distributed in the battery compartment.

[0064] The number of fire extinguishing devices and fire detectors are related to the volume and area of ​​the battery compartment.

[0065] In one example, multiple fire extinguishing devices can be arranged above the battery clusters. For instance, if the number of fire extinguishing devices 5 is exactly equal to the number of battery clusters 20, then one fire extinguishing device can be arranged above each battery cluster. As described above, a converter 3 is arranged above each battery cluster 20. Therefore, referring to... Figure 2 As shown, the fire extinguishing device 5 can be arranged above the converter 3.

[0066] The fire extinguishing device 5 contains a fire extinguishing agent, which may be perfluorohexanone or heptafluoropropane.

[0067] In one example, a fire detector may include a smoke detector, a temperature detector, and a combustible gas detector.

[0068] In one example, refer to Figure 1 As shown, a water spray assembly 7 is arranged inside the container and on the top. The water spray assembly 7 includes a water pipe and a spray head installed on the water pipe. The water pipe is used to connect to a water tank, which may be arranged in the electrical compartment or the battery compartment.

[0069] In one example, the container also has explosion-proof features, such as pressure relief vents on the side walls and top of the battery compartment. In the event of high air pressure inside the battery compartment, pressure is released outward through the pressure relief vents to prevent the energy storage device from exploding.

[0070] In one example, since the application scenario of the energy storage device is not limited and it can be moved to any scenario for use, the energy storage device needs to meet low noise requirements. For example, the liquid-cooled unit 6 arranged in the electrical compartment can reduce air volume requirements, fan speed and compressor frequency by increasing the heat exchange area, thereby reducing noise.

[0071] Meanwhile, sound-absorbing cotton and perforated panels are laid around the liquid-cooled unit and on the container to achieve overall noise reduction, so that the noise of the energy storage equipment meets the requirement of less than or equal to 65dB(A)@1m. Here, 65dB(A)@1m means that at a distance of one meter from the energy storage equipment, the noise measured using A-weighted measurement does not exceed 65 decibels.

[0072] In this way, the energy storage equipment has good noise control under rated operating conditions, making it suitable for noise-sensitive areas (such as residential areas and hospitals).

[0073] In one example, the liquid cooling unit can be top-exhaust, for example, the top of the container has an exhaust vent.

[0074] In one example, to facilitate the movement of the energy storage device, the bottom of the energy storage device may have rollers. For example, the bottom of a container may have multiple rollers and a braking structure (such as a foot brake) for braking the rollers.

[0075] Furthermore, also based on the fact that energy storage devices need to be moved frequently, therefore, referring to Figure 2 As shown, multiple lifting structures 11 for lifting can be arranged on the front and rear sides of container 1.

[0076] In this embodiment, the energy storage device includes multiple converters, each of which is electrically connected to one or more battery clusters; for example, one converter is electrically connected to one battery cluster. Compared to connecting all battery clusters in series with a single converter, this approach allows a single converter to monitor and control a smaller number of battery clusters, resulting in higher control accuracy. It also optimizes the circulating current problem of traditional centralized converters, thereby improving the energy efficiency of the energy storage system.

[0077] In addition, the rated voltage of the DC power output by the battery clusters in the energy storage device does not exceed 1000V, which enables the converter in the energy storage device to directly convert the DC power into a low voltage that the load can use. This allows the energy storage device to be used in an off-grid state without the need for an additional isolation transformer, thus improving the application flexibility of the energy storage device.

[0078] In this application, the interfaces for connecting to the power grid and the interfaces for connecting to the load are both arranged on the panel of the distribution cabinet to facilitate operation by the staff. Moreover, these electrical interfaces are all quick-connect interfaces to achieve plug-and-play functionality.

[0079] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An energy storage device, characterized in that, The energy storage device includes a container (1), multiple battery packs (2), multiple converters (3) and a power distribution cabinet (4), wherein the container (1) includes a battery compartment and an electrical compartment; The multiple battery packs (2) are connected in series and arranged in the battery compartment. The DC side of each converter (3) is electrically connected to at least one battery cluster (20), and the AC side of the multiple converters (3) is electrically connected to the power distribution cabinet (4).

2. The energy storage device according to claim 1, characterized in that, Each battery cluster (20) outputs a rated voltage of less than or equal to 1000V.

3. The energy storage device according to claim 1 or 2, characterized in that, The DC side of each converter (3) is electrically connected to a battery cluster (20).

4. The energy storage device according to any one of claims 1 to 3, characterized in that, Each converter (3) is a three-phase four-wire converter, and the AC side interface (31) of the converter (3) is a three-phase four-wire interface.

5. The energy storage device according to any one of claims 1 to 4, characterized in that, Each converter (3) integrates a high-voltage box function for electrical isolation, short-circuit protection and pre-charge management between the electrically connected converter (3) and the battery cluster (20).

6. The energy storage device according to any one of claims 1 to 5, characterized in that, Each converter (3) is arranged on top of the connected battery cluster (20).

7. The energy storage device according to any one of claims 1 to 6, characterized in that, Each battery cluster (20) includes five battery packs (2), and the five battery packs (2) of each battery cluster (20) are stacked in the height direction of the container (1).

8. The energy storage device according to any one of claims 1 to 7, characterized in that, The panel of the distribution cabinet (4) has a quick-connect interface for connecting the load and a quick-connect interface for connecting to the power grid.

9. The energy storage device according to claim 8, characterized in that, The door of the electrical compartment has a window at the location of the corresponding quick-connect connector for cables to pass through.

10. The energy storage device according to any one of claims 1 to 9, characterized in that, The energy storage device also includes a charging pile, which is arranged in the electrical compartment and electrically connected to the power distribution cabinet (4). The charging gun of the charging pile is used to charge electric vehicles.

11. The energy storage device according to any one of claims 1 to 10, characterized in that, The fire protection system of the energy storage device is a non-piped fire protection system. The fire protection system includes multiple fire extinguishing devices (5) and multiple fire detectors, wherein the multiple fire extinguishing devices (5) and the multiple fire detectors are arranged in the battery compartment.

12. The energy storage device according to claim 11, characterized in that, The fire detectors include smoke detectors, temperature detectors, and combustible gas detectors.

13. The energy storage device according to claim 11, characterized in that, The fire extinguishing device (5) is a non-pressurized gas fire extinguishing device, and the fire extinguishing device (5) is arranged above the battery cluster (20).

14. The energy storage device according to any one of claims 1 to 13, characterized in that, The battery compartment is equipped with a water spray assembly (7) inside and on top, wherein the water spray assembly (7) includes a water pipe and a spray head installed on the water pipe.

15. The energy storage device according to any one of claims 1 to 14, characterized in that, The noise level at a distance of one meter from the container is less than or equal to 65 dB.

16. The energy storage device according to any one of claims 1 to 15, characterized in that, The container is a 20-foot flat rack container.

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