Energy storage device and energy storage system

Abstract

The utility model relates to an energy storage device and an energy storage system, an energy storage circuit and a resistor are configured in a shell of an energy storage sub-device, a primary device with a relatively high voltage level in the energy storage circuit is electrically connected to any position point of the shell through the resistor, and the rest position of the shell and the energy storage circuit are arranged in an insulated and isolated manner. In this way, the potential of the shell is fixed according to the voltage of the primary equipment, and the current flowing through the shell is limited to be smaller than or equal to a preset safety current threshold value, that is, high-resistance one-point connection between the energy storage circuit and the shell is achieved through the resistor. Meanwhile, the energy storage device is further provided with a ground insulation assembly, and the ground insulation assembly bears all the energy storage sub-devices and bears the voltage to ground of the energy storage sub-devices. According to the scheme, the potential of the shell is fixed in a high-resistance one-point connection mode, and the situation that the potential of the shell is suspended and the insulation safety of primary equipment in the energy storage circuit is endangered is reduced, so that the energy storage sub-equipment can be stacked without interlayer insulation.

Description

Technical Field

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

[0002] With the development of new energy technologies, electrochemical energy storage systems using batteries as energy storage components are gradually being applied in production and daily life, greatly improving the convenience of electricity use. To meet the large capacity demands of the power grid, the number of cascaded energy storage sub-modules in cascaded electrochemical energy storage systems is increasing, significantly increasing the footprint of the energy storage system. Utility Model Content

[0003] Therefore, it is necessary to propose an energy storage device and system to alleviate the problem of excessive land occupation of energy storage systems and reduce the land required for the construction of energy storage power stations.

[0004] This application provides an energy storage device, including a ground insulation component and multiple energy storage sub-devices, which are stacked and contacted sequentially. Each energy storage sub-device includes a housing, an energy storage circuit, and a resistor. The energy storage circuits in adjacent layers of energy storage sub-devices are electrically connected. Both the energy storage circuit and the resistor are disposed inside the housing. A first end of the resistor is electrically connected to any primary device of the energy storage circuit, and a second end of the resistor is electrically connected to any point on the housing. The remaining positions of the housing are insulated from the energy storage circuit. The resistor is used to fix the potential of the housing according to the voltage of the primary device and to limit the current flowing through the housing to less than or equal to a preset safe current threshold. The ground insulation component is disposed on the ground and is used to support the energy storage sub-devices.

[0005] The aforementioned energy storage device incorporates energy storage circuits and resistors within the casing of its sub-units. Primary devices with relatively high voltage levels in the energy storage circuit are electrically connected to any point on the casing via resistors. The remaining areas of the casing are insulated from the energy storage circuit. This fixes the casing's potential based on the voltage of the primary devices and limits the current flowing through the casing to a preset safe current threshold. In other words, the resistors achieve a high-resistance point connection between the energy storage circuit and the casing. Simultaneously, the energy storage device is equipped with ground insulation components to support each sub-unit and bear its ground voltage. This scheme fixes the casing potential through a high-resistance point connection, reducing the risk of floating casing potential that could compromise the insulation safety of the primary devices in the energy storage circuit. It also allows for stacked configurations of the sub-units without the need for interlayer insulation. Thus, while maintaining the insulation safety of the energy storage device, it effectively reduces the footprint of the sub-units, alleviating the problem of excessively large land areas for energy storage systems built on this type of device and reducing the land required for energy storage power station construction.

[0006] In some embodiments, the number of energy storage sub-devices is two.

[0007] In the above scheme, each energy storage device includes two energy storage sub-devices arranged in a stacked and contacted manner. This not only reduces the overall footprint of the energy storage sub-devices, but also reduces the load on the bottommost energy storage sub-device, thus reducing the risk of the energy storage sub-devices being crushed.

[0008] In some embodiments, the resistance of the resistive element is greater than or equal to 1 megohm.

[0009] The above solution sets the resistance value of the resistor to the megohm level, thereby limiting the current flowing into the casing of the energy storage sub-device to the milliampere level and improving the operational safety of the energy storage sub-device.

[0010] In some embodiments, the housings of the energy storage sub-devices in adjacent layers are equipotentially connected.

[0011] The above scheme connects the shells of adjacent energy storage sub-devices at the same potential, reducing the discharge interference caused by poor contact between layers and further improving the operational safety of the energy storage sub-devices.

[0012] In some embodiments, the housings of the energy storage sub-devices in adjacent layers are electrically connected by bolts.

[0013] The above scheme achieves equipotential bonding between adjacent energy storage sub-devices by means of bolted electrical connection. While maintaining the same potential between the shells of adjacent layers, it can also fix the energy storage sub-devices of adjacent layers, reducing the risk of the upper energy storage sub-devices slipping off.

[0014] In some embodiments, the height of the ground insulation component is positively correlated with the number of energy storage sub-devices.

[0015] The above scheme configures ground insulation components of different heights depending on the number of energy storage sub-devices in the stacked contact arrangement. The more energy storage sub-devices there are, the higher the ground insulation components should be, which greatly improves the ground insulation safety of the energy storage device.

[0016] In some embodiments, the primary device of the energy storage circuit includes a battery and an energy storage converter, wherein the battery is electrically connected to the energy storage converter, and a first end of the resistor is electrically connected to the battery, or a first end of the resistor is electrically connected to the energy storage converter.

[0017] The above solution allows the battery or energy storage converter in the energy storage circuit to be connected to a high-resistance point on the casing via a resistor, thereby fixing the potential of the casing at a higher potential. This solution has the advantage of being simple to implement.

[0018] In some embodiments, the primary device of the energy storage circuit includes a battery, a voltage equalizing resistor, and an energy storage converter. A first end of the voltage equalizing resistor is electrically connected to a first end of the battery and a first end of the energy storage converter. A first end of the resistor is electrically connected to a second end of the battery and a second end of the energy storage converter. A second end of the resistor is electrically connected to a second end of the voltage equalizing resistor and the housing.

[0019] The above solution uses resistive components and voltage divider resistors in the energy storage circuit to obtain a stable, low-noise reference potential through resistive voltage division, thereby fixing the potential of the casing. It has a better common-mode noise suppression effect and effectively maintains the stability of the casing potential.

[0020] In some embodiments, the voltage equalizing resistor has the same resistance value as the resistive element.

[0021] The above solution configures the resistance values ​​of the voltage equalizing resistor and the resistor to be consistent, thereby fixing the potential of the casing at half of the battery voltage through resistive voltage division, improving the symmetry and voltage equalization consistency of the energy storage sub-device, and thus improving the electrical performance stability of the energy storage sub-device.

[0022] This application also provides an energy storage system, including a plurality of energy storage devices as described above, wherein the energy storage devices are cascaded together. Attached Figure Description

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0024] Figure 1 These are schematic diagrams of the energy storage device structure in some embodiments of this application;

[0025] Figure 2 This is a schematic diagram of the voltage waveform of the upper-layer energy storage sub-device in some embodiments of this application;

[0026] Figure 3 This is a schematic diagram of the voltage waveforms of the upper and lower energy storage sub-devices in some embodiments of this application;

[0027] Figure 4 This is a schematic diagram of interlayer current waveforms in some embodiments of this application;

[0028] Figure 5 This is a schematic diagram of the energy storage sub-device structure in some embodiments of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10-Energy storage sub-equipment, 20-Establishment component to ground, R1-Equalizing resistor, R2-Resistor, 11-Battery, 12-Energy storage converter, 13-Housing, L1-Filter inductor, C1-Filter capacitor. Detailed Implementation

[0031] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0036] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] Currently, judging from market trends, battery applications are becoming increasingly widespread. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. As the application areas of batteries continue to expand, the market demand is also constantly increasing.

[0039] Energy storage systems typically consist of multiple interconnected (series and / or parallel) energy storage submodules. The exterior of each submodule is a casing, inside which are primary devices with relatively high voltage levels, such as batteries and energy storage converters, as well as secondary devices with relatively low voltage levels, such as power boards, switch driver boards, and bypass switch driver boards. Depending on the required voltage level, the batteries in each submodule usually consist of multiple battery cells connected in series and / or parallel. Thus, a single energy storage submodule can be relatively large, and its weight can reach several tons.

[0040] As the capacity demand of the power grid increases, the number of energy storage submodules connected to energy storage systems continues to rise. Therefore, the increased number of energy storage submodules leads to a larger footprint for energy storage power stations, resulting in a waste of land resources.

[0041] Research has revealed that while individual energy storage submodules are relatively large in mass and volume, their height is limited, leaving space above them available for utilization. Therefore, a stacked layout could be considered to reduce the overall footprint of the energy storage submodules.

[0042] However, if energy storage submodules are stacked, interlayer insulation is required between adjacent layers to ensure their insulation safety. However, the weight of energy storage submodules is significant, and interlayer insulation can affect their load-bearing capacity, increasing costs, making on-site installation more difficult, and, more importantly, increasing the net height of the energy storage power station (potentially making it unsuitable for energy storage scenarios). Furthermore, insufficient design margins in the interlayer insulation, or adverse atmospheric conditions, could potentially create localized discharge sources, causing interference.

[0043] To alleviate the above phenomenon, it is possible to consider internal insulation design for individual energy storage submodules, so that there is no need for interlayer insulation between energy storage submodules, and they can be stacked. This reduces the footprint of the energy storage power station and slows down the increase in height caused by stacking.

[0044] Based on the above considerations, this application provides an energy storage device. An energy storage circuit and a resistor are configured inside the casing of the energy storage sub-devices. A primary device with a relatively high voltage level in the energy storage circuit is electrically connected to any point on the casing via the resistor. This fixes the potential of the casing based on the voltage of the primary device and limits the current flowing through the casing to less than or equal to a preset safe current threshold. In other words, the high-resistance point connection between the energy storage circuit and the casing is achieved through the resistor. Simultaneously, the energy storage device is also equipped with a ground insulation component to support each energy storage sub-device and bear the ground voltage of the energy storage sub-devices.

[0045] The above-described scheme uses a high-resistance single-point connection to fix the shell potential, reducing the risk of floating shell potential that could jeopardize the insulation safety of primary equipment in the energy storage circuit. This allows for stacked configuration of various energy storage sub-devices without the need for interlayer insulation. Thus, while maintaining the insulation safety of the energy storage device, the footprint of the energy storage sub-devices is effectively reduced, thereby alleviating the problem of excessively large footprints in energy storage systems built on this type of device and reducing the land required for energy storage power stations.

[0046] The energy storage device provided in this application is applied to an energy storage system, which includes multiple energy storage devices. These devices can be connected in series or by other means, without any specific limitation. In some embodiments, the energy storage device of this application is used in energy storage systems with relatively high capacity requirements, such as 35kV AC direct-connected energy storage systems, etc., without any limitation.

[0047] Please see Figure 1 This application provides an energy storage device, including a ground insulation component 20 and multiple energy storage sub-devices 10 (two are shown as an example in the figure). Each energy storage sub-device 10 is stacked and contacted in sequence. Each energy storage sub-device 10 includes a housing, an energy storage circuit, and a resistor (not shown in the figure). The energy storage circuits in adjacent layers of energy storage sub-devices 10 are electrically connected to each other. The energy storage circuit and the resistor are both disposed inside the housing. The first end of the resistor is electrically connected to any primary device of the energy storage circuit, and the second end of the resistor is electrically connected to any point on the housing. The remaining positions of the housing are insulated from the energy storage circuit. The resistor is used to fix the potential of the housing according to the voltage of the primary device and to limit the current flowing through the housing to less than or equal to a preset safe current threshold. The ground insulation component 20 is disposed on the ground and is used to support the energy storage sub-devices 10.

[0048] Specifically, the energy storage device is a device formed by connecting two or more energy storage sub-devices 10, which has the function of storing electrical energy. The ground insulation component 20 is an insulation device installed between the live equipment (such as the energy storage sub-device 10 of this application) and the ground, which can prevent current from flowing from the live equipment to the ground, while providing stable mechanical support. The stacked contact arrangement means that the housings of the energy storage sub-devices 10 are directly contacted and stacked, with one energy storage sub-device 10 configured on each layer. In this way, there is no need for interlayer insulation and other configurations, which alleviates the increase in height caused by stacking.

[0049] The energy storage sub-device 10 is a modular, standardized, and independently operable complete unit that integrates the battery, battery management system, energy storage converter, and control system. It is understood that the type of energy storage sub-device 10 is not unique; it can be an energy storage container (also called an energy storage sub-module), an energy storage cabinet, or a battery cabinet, and is not limited here. In this embodiment, the energy storage sub-device 10 includes a housing and an energy storage circuit, wherein the energy storage circuit is the circuit formed by integrating the battery, battery management system, energy storage converter, and control system, and is disposed inside the housing, thereby forming the modular energy storage sub-device 10.

[0050] In the energy storage circuit of the primary device, i.e., the energy storage sub-device 10, the devices that directly participate in the production, transmission, or distribution of electrical energy are not of a single type and will vary depending on the energy storage circuit. In some embodiments, the primary device may include a battery, an energy storage converter, and devices connected between the battery and the energy storage converter (such as filter capacitors, filter inductors, etc.). The energy storage circuit should also include secondary devices, which focus on control, protection, and monitoring, such as power boards, switch boards, etc. Therefore, in the energy storage circuit, the voltage of the primary device is usually higher than the voltage of the secondary device.

[0051] A resistor is used to connect the primary device to the housing, thereby fixing the potential of the housing with the voltage of the primary device and limiting the current flowing through the housing to be less than or equal to a preset safe current threshold. The preset safe current threshold is a pre-set current value that will not endanger human safety. Its value is not unique; in one embodiment, the preset safe current threshold can be 1mA to 10mA, while in another embodiment, it can be configured to be less than 1mA or greater than 10mA, without specific limitation.

[0052] It should be noted that the resistance value of the resistor is not unique. In one embodiment, it is configured according to the voltage level of the energy storage sub-device 10 and a preset safe current threshold. For example, the resistance value of the resistor is determined by dividing the voltage of a single energy storage sub-device 10 by the preset safe current threshold, and there is no specific limitation.

[0053] It is understandable that, in order to limit the current flowing through the casing to less than or equal to the preset safe current threshold, the resistance value of the resistor is usually set to be relatively large. The second end of the resistor is connected to the casing at only one point, and the remaining positions of the casing are insulated from the energy storage circuit. In this way, a high-resistance single-point connection between the primary equipment of the energy storage sub-device 10 and the casing can be achieved, thereby achieving: (1) fixing the potential of the casing of the energy storage sub-device 10, reducing the situation where the casing potential floats and endangers the insulation safety of the internal primary equipment; (2) a single-point connection instead of multiple-point connection, thereby reducing the situation where a loop is formed and circulating current is generated; (3) the high-resistance connection can limit the amplitude of the interlayer current.

[0054] In the embodiments of this application, each energy storage sub-device 10 stacked in the energy storage device adopts the same configuration, so that each energy storage sub-device 10 can be universal and interchangeable.

[0055] The following explanation uses a 35kV energy storage system as an example, where two energy storage sub-devices are stacked in 10 layers. Figure 2 The graph shows the voltage waveforms of the upper-level energy storage device 10 with and without interlayer insulation. The horizontal axis represents time, and the vertical axis represents voltage. The upper curve represents the total positive voltage of the battery relative to the casing, and the lower curve represents the total negative voltage of the battery relative to the casing. As can be seen from the graph, after removing the interlayer insulation, both the total positive voltage of the battery relative to the casing and the total negative voltage of the battery relative to the casing increase, but the maximum voltage amplitude (i.e., the difference between the two) remains basically at 2000V. Figure 3 The graph shows the voltage waveforms of the upper-level energy storage device 10 with and without interlayer insulation. The horizontal axis represents time, and the vertical axis represents voltage. The upper curve represents the total positive voltage of the battery relative to the casing, and the lower curve represents the total negative voltage of the battery relative to the casing. As can be seen from the graph, after removing the interlayer insulation, both the total positive voltage of the battery relative to the casing and the total negative voltage of the battery relative to the casing decrease, but the maximum voltage amplitude remains basically at 2000V. Therefore, removing the interlayer insulation does not affect the original insulation design inside the energy storage device 10; that is, under the high-resistance point-connection insulation scheme, interlayer insulation is not required.

[0056] The aforementioned energy storage device includes an energy storage circuit and a resistor inside the housing of the energy storage sub-device 10. The primary equipment with a relatively high voltage level in the energy storage circuit is electrically connected to any point on the housing via the resistor. The remaining parts of the housing are insulated from the energy storage circuit. This fixes the housing potential based on the voltage of the primary equipment and limits the current flowing through the housing to less than or equal to a preset safe current threshold. In other words, the resistor achieves a high-resistance point connection between the energy storage circuit and the housing. Simultaneously, the energy storage device is also equipped with a ground insulation component 20, which supports each energy storage sub-device 10 and bears the ground voltage of each sub-device. This scheme fixes the housing potential through a high-resistance point connection, reducing the risk of floating housing potential that could endanger the insulation safety of the primary equipment in the energy storage circuit. It also allows for stacked configuration of the various energy storage sub-devices 10 without the need for interlayer insulation. In this way, while maintaining the insulation safety of the energy storage device, the footprint of the energy storage sub-equipment 10 is effectively reduced, thereby alleviating the problem of excessive footprint of the energy storage system built based on this type of energy storage device and reducing the construction land of the energy storage power station.

[0057] In some embodiments, the number of energy storage sub-devices 10 is two.

[0058] Specifically, in this embodiment, two energy storage modules are stacked and contacted. In this way, the bottommost energy storage sub-device 10 only needs to bear the weight of one energy storage sub-device 10, and the ground insulation component 20 only needs to bear the weight of two energy storage sub-devices 10, thereby reducing the pressure on the lower energy storage sub-device 10 and the ground insulation component 20 and improving the operational stability of the energy storage device.

[0059] In the above scheme, each energy storage device includes two energy storage sub-devices 10 arranged in a stacked and contacted manner. This not only reduces the overall footprint of the energy storage sub-devices 10, but also reduces the load on the bottommost energy storage sub-device 10, thereby reducing the risk of the energy storage sub-device 10 being crushed.

[0060] In some embodiments, the resistance of the resistor is greater than or equal to 1 megohm.

[0061] Specifically, as shown in the above embodiment, the resistance value of the resistor should be configured to be large enough so that the current flowing through the casing is less than or equal to a preset safe current threshold. In this embodiment, the resistance value of the resistor is configured to be in the megaohm range, that is, greater than or equal to 1 megaohm, thereby limiting the amplitude of the interlayer current to the milliampere level. In addition, since its nature is a ground capacitance current, it has no impact on the safe operation of the energy storage device.

[0062] In some embodiments, the resistance value of the resistor can be configured to be greater than or equal to 1 megohm and less than or equal to 100 megohms; further, in one embodiment, the resistance value of the resistor can be configured to be greater than or equal to 1 megohm and less than or equal to 10 megohms. For example, in one embodiment, taking a 35kV energy storage system as an example, the resistance value of the resistor can be configured to 2.5MΩ (megohms), and the current waveform flowing through the casing can be found in the figure. Figure 4 The horizontal axis represents time, and the vertical axis represents current. The graph shows that without interlayer insulation, the peak current reaches 1 x 10⁻⁶. -3 A (ampere), which is 1mA.

[0063] The above solution sets the resistance value of the resistor to the megohm level, thereby limiting the current flowing into the casing of the energy storage sub-device 10 to the milliampere level, thus improving the operational safety of the energy storage sub-device 10.

[0064] The above analysis shows that, with the high-resistance single-point grounding scheme adopted for the energy storage sub-device 10, even without interlayer insulation between the energy storage sub-devices 10, the energy storage sub-device 10 can reliably achieve external insulation and maintain safe operation. Thus, taking two layers as an example, the interlayer insulation can be reduced by approximately 150mm to 350mm. If the number of stacked energy storage sub-devices 10 is greater, even more height can be saved.

[0065] In some embodiments, the housings of adjacent energy storage sub-devices 10 are equipotentially connected.

[0066] Specifically, in practical scenarios, by using a high-resistance single-point grounding method, the casings of each stacked energy storage sub-device 10 can be fixed at the same potential. If poor contact occurs between layers (such as when there is insulating varnish on the outside of the casing), discharge interference will occur. Therefore, this embodiment requires equipotential bonding between adjacent layers of energy storage sub-devices 10.

[0067] The above scheme connects the shells of adjacent energy storage sub-devices 10 at the same potential, reduces the discharge interference caused by poor contact between layers, and further improves the operational safety of the energy storage sub-devices 10.

[0068] The method of equipotential bonding is not unique. In one embodiment, the conductive metal portions of adjacent housing layers can be connected by wires. In some embodiments, the housings of adjacent energy storage sub-devices 10 are electrically connected by bolts. Specifically, one or more bolts can be used to fix the housings for electrical connection, which is not limited here.

[0069] In the above scheme, the energy storage sub-devices 10 in adjacent layers are connected by bolts to achieve equipotential bonding. While maintaining the same potential between the shells of adjacent layers, the energy storage sub-devices 10 in adjacent layers can also be fixed, reducing the risk of the upper energy storage sub-devices 10 slipping off.

[0070] In some embodiments, based on the high-resistance single-point connection, the energy storage circuit inside the housing is also insulated from the housing. The implementation method is not unique. In one embodiment, an insulating isolator can be configured between the housing and the energy storage circuit. In another embodiment, each component in the energy storage circuit can be insulated separately. The specific implementation is not limited.

[0071] In some embodiments, the height of the ground insulation component 20 is positively correlated with the number of energy storage sub-devices 10.

[0072] Specifically, the ground insulation component 20 is constructed using insulating materials, which supports and isolates the energy storage device from the ground, thereby achieving ground insulation operation. In practical scenarios, the more energy storage sub-devices 10 there are, the higher the voltage level of the energy storage device will be, and the greater its insulation requirements will be. Therefore, the height of the ground insulation component can be configured accordingly to be higher.

[0073] For example, in one embodiment, the ground insulation component 20 of a two-layer energy storage device can be configured to be 450mm-600mm. When the energy storage device includes three or more layers, the height of the ground insulation component 20 can be configured to be greater than 600mm.

[0074] The above scheme configures ground insulation components 20 of different heights according to the number of energy storage sub-devices 10 stacked in contact. The more energy storage sub-devices 10 there are, the higher the height of the ground insulation components are, which greatly improves the ground insulation safety of the energy storage device.

[0075] It is understood that the structure and number of ground insulation components 20 are not unique, as long as they can support the energy storage sub-device 10 and provide insulation to the ground. For example, in one embodiment, there are four ground insulation components 20, which are respectively arranged at the four corners of the bottommost energy storage sub-device 10. In another embodiment, the ground insulation components 20 may be configured as one or other numbers, and there is no specific limitation.

[0076] It should be noted that in some embodiments, since the casing of the energy storage sub-device 10 is energized, the insulation of the casing to ground is achieved by the ground insulation component 20. Therefore, the ground insulation component 20, which undertakes the insulation to ground, should be designed according to the voltage level of the energy storage system to improve the safety of the insulation to ground.

[0077] For example, in one embodiment, the energy storage system is a 35kV AC direct-connected energy storage system. In this case, the rated voltage of the ground insulation component 20 is also 35kV, its AC withstand voltage amplitude is not less than 95kV, and its lightning impulse withstand voltage peak is not less than 185kV.

[0078] It should be noted that the implementation of a high-resistance single-point connection is not unique; it is sufficient to connect the first end of the resistor to any primary device and electrically connect the second end of the resistor to the housing. In some embodiments, the primary devices of the energy storage circuit include a battery and an energy storage converter, with the battery electrically connected to the energy storage converter and the first end of the resistor electrically connected to either the battery or the energy storage converter.

[0079] In practical scenarios, the first end of the resistor can be connected to the positive or negative terminal of the battery, the positive or negative terminal of the energy storage converter, or the bus connecting the battery and the energy storage converter, etc. There are no restrictions here.

[0080] The above solution allows the battery or energy storage converter in the energy storage circuit to be connected to a high-resistance point on the casing via a resistor, thereby fixing the potential of the casing at a higher potential. This solution has the advantage of being simple to implement.

[0081] Please see Figure 5 In some embodiments, the primary device of the energy storage circuit includes a battery 11, a voltage equalization resistor R1, and an energy storage converter 12. The first end of the voltage equalization resistor R1 is electrically connected to the first end of the battery 11 and the first end of the energy storage converter 12. The first end of the resistor R2 is electrically connected to the second end of the battery 11 and the second end of the energy storage converter 12. The second end of the resistor R2 is electrically connected to the second end of the voltage equalization resistor R1 and the housing 13.

[0082] Specifically, in this embodiment, a voltage divider is used, with a resistor R2 connected in series at the voltage equalization resistor R1, and the common terminal between the voltage equalization resistor R1 and the resistor R2 is connected to the housing 13, thereby achieving a high-resistance single-point connection.

[0083] In some embodiments, a filter inductor L1 is connected in series between the first terminal of the battery 11 and the first terminal of the voltage equalizing resistor R1, and a filter capacitor C1 is connected in parallel across the series structure of the voltage equalizing resistor R1 and the resistor R2, thereby improving the operational reliability of the energy storage circuit. Correspondingly, the filter inductor L1 and the filter capacitor C1 can also be used as primary devices, with the first terminal of the resistor R2 connected to either the filter inductor L1 or the filter capacitor C1, depending on the actual requirements.

[0084] The above scheme uses resistor R2 and voltage divider resistors in the energy storage circuit to obtain a stable, low-noise reference potential by means of resistor voltage division, thereby fixing the potential of housing 13, which has a better common-mode noise suppression effect and effectively maintains the stability of the potential of housing 13.

[0085] In some embodiments, the resistance values ​​of the voltage equalizing resistor and the resistor are the same. If the resistance value of the voltage equalizing resistor R1 is configured to be the same as that of the resistor R2, the potential of the housing 13 can be fixed at half the voltage of the battery 11 under the voltage division of the voltage equalizing resistor and the resistor. In this way, the symmetry and voltage equalization consistency of the energy storage sub-device 10 can be improved, thereby improving the electrical performance stability of the energy storage sub-device 10.

[0086] To facilitate understanding of the technical solution of this application, the following detailed embodiments will be used to explain and illustrate this application.

[0087] In this embodiment, there are two energy storage sub-devices 10, including an upper sub-module and a lower sub-module. The lower sub-module is supported by a ground insulation component 20 and bears the ground voltage of the sub-module. The upper sub-module is directly stacked on top of the lower sub-module without any insulation isolation in between. To achieve safe stacking without interlayer insulation, the primary equipment (battery 11 or energy storage converter 12, etc.) inside the energy storage sub-device 10 is connected to the housing 13 with a high-resistance single-point connection, while the remaining space of the housing is insulated from the energy storage circuit. For details, please refer to the relevant documentation. Figure 5 The primary components of the energy storage circuit include a battery 11, a voltage equalizing resistor R1, and an energy storage converter 12. The first terminal of the voltage equalizing resistor R1 is electrically connected to the first terminal of the battery 11 and the first terminal of the energy storage converter 12. The first terminal of a resistor R2 is electrically connected to the second terminal of the battery 11 and the second terminal of the energy storage converter 12. The second terminal of the resistor R2 is electrically connected to the second terminal of the voltage equalizing resistor R1 and the housing 13. The resistance value of the resistor R2 is configured in the megaohm range (i.e., between 1MΩ and 10MΩ), thereby limiting the interlayer current to the mA level. Furthermore, to reduce discharge interference caused by poor interlayer contact, the upper and lower submodule housings 13 are fixed together with bolts to form an equipotential electrical connection.

[0088] Thus, the energy storage device adopts a sub-module stacked design, which can greatly reduce the footprint. By eliminating inter-module insulation and using a direct stacking design, the upper and lower sub-modules are at the same potential, simplifying the stress structure of the sub-module shell 13. At the same time, it can reduce the stacking height by 150mm-350mm, save on inter-module insulation costs, significantly improve on-site installation efficiency, and reduce building height (indoor type). Furthermore, all sub-modules are of the same universal design, improving sub-module interchangeability and reducing interference caused by surface discharge of inter-module insulation.

[0089] This application also provides an energy storage system, including multiple energy storage devices as described above, which are cascaded together.

[0090] Specifically, the structure and implementation of the energy storage device are as shown in the above embodiments and accompanying drawings, and will not be repeated here. In this energy storage system, an energy storage circuit and a resistor R2 are configured inside the housing 13 of the energy storage sub-device 10. The primary devices with relatively high voltage levels in the energy storage circuit are electrically connected to any point on the housing 13 via the resistor R2. The remaining positions on the housing are insulated from the energy storage circuit. This fixes the potential of the housing 13 according to the voltage of the primary devices and limits the current flowing through the housing 13 to less than or equal to a preset safe current threshold. In other words, the high-resistance point connection between the energy storage circuit and the housing 13 is achieved through the resistor R2. Simultaneously, the energy storage device is also equipped with a ground insulation component 20, which carries each energy storage sub-device 10 and bears the ground voltage of the energy storage sub-devices 10. Through this scheme, the potential of the housing 13 is fixed by a high-resistance point connection, reducing the possibility of the housing 13 potential floating and endangering the insulation safety of the primary devices in the energy storage circuit. This allows the various energy storage sub-devices 10 to be stacked without interlayer insulation. In this way, while maintaining the insulation safety of the energy storage device, the footprint of the energy storage sub-equipment 10 is effectively reduced, thereby alleviating the problem of excessive footprint of the energy storage system built based on this type of energy storage device and reducing the construction land of the energy storage power station.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An energy storage device, characterized by, The energy storage device comprises: a plurality of energy storage sub-devices, each of which is arranged in contact in sequence, and each of which comprises a shell, an energy storage circuit, and a resistor, the energy storage circuits of adjacent layers are electrically connected, the energy storage circuit and the resistor are arranged in the interior of the shell, the first end of the resistor is electrically connected to any primary device of the energy storage circuit, the second end of the resistor is electrically connected to any position point of the shell, and the remaining positions of the shell are insulated and separated from the energy storage circuit; the resistor is used to fix the potential of the shell according to the voltage of the primary device, and limit the current flowing through the shell to be less than or equal to a preset safety current threshold; a ground insulation assembly arranged on the ground and used to carry the energy storage sub-devices.

2. The energy storage device of claim 1, wherein, The number of the energy storage sub-devices is two.

3. The energy storage device of claim 1, wherein, The resistance of the resistor is greater than or equal to 1 megaohm.

4. The energy storage device of claim 1, wherein, The shells of the energy storage sub-devices of adjacent layers are electrically connected.

5. The energy storage device of claim 4, wherein, The shells of the energy storage sub-devices of adjacent layers are electrically connected through bolts.

6. The energy storage device of any of claims 1-5, wherein, The height of the ground insulation assembly is positively correlated with the number of the energy storage sub-devices.

7. The energy storage device of any of claims 1-5, wherein, The primary device of the energy storage circuit comprises a battery and an energy storage converter, the battery is electrically connected to the energy storage converter, and the first end of the resistor is electrically connected to the battery or the energy storage converter.

8. The energy storage device of any of claims 1-5, wherein, The primary device of the energy storage circuit comprises a battery, a voltage-sharing resistor, and an energy storage converter, the first end of the voltage-sharing resistor is electrically connected to the first end of the battery and the first end of the energy storage converter, the first end of the resistor is electrically connected to the second end of the battery and the second end of the energy storage converter, and the second end of the resistor is electrically connected to the second end of the voltage-sharing resistor and the shell.

9. The energy storage device of claim 8, wherein, The resistance of the voltage-sharing resistor is consistent with that of the resistor.

10. An energy storage system characterized by, A plurality of energy storage devices as claimed in any one of claims 1-9 are connected in cascade.

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