Charging and discharging circuit and energy storage system

Abstract

The embodiment of the utility model provides a charging and discharging circuit and an energy storage system, the charging and discharging circuit comprises a main positive relay, a main negative relay, an isolation switch, a pre-charging loop and a load, the main positive relay, the isolation switch, the main negative relay and the load are connected in series, and the pre-charging loop is used for adjusting the charging and discharging current of the charging and discharging circuit. And the pre-charging loop is connected in parallel with the isolating switch. The reliability and the stability of the charging and discharging circuit can be improved while the failure risk of the isolating switch is reduced.

Description

Technical Field

[0001] The present application relates to the field of energy storage, and more specifically, to a charging and discharging circuit and an energy storage system. Background Art

[0002] As the world increases its support for the development of new energy technologies, various technologies related to energy storage have been widely used. In order to meet the demand for large-capacity energy storage devices, it is necessary to manage the battery system. Therefore, how to effectively manage the energy storage system is an urgent problem to be solved. Utility Model Content

[0003] The embodiments of the present application provide a charging and discharging circuit and an energy storage system, which can reduce the failure risk of the isolating switch while improving the reliability and stability of the charging and discharging circuit.

[0004] In the first aspect, the present application provides a charging and discharging circuit, including a main positive relay, a main negative relay, an isolating switch, a pre-charging circuit and a load. The main positive relay, the isolating switch, the main negative relay and the load are connected in series. The pre-charging circuit is used to adjust the charging and discharging current of the charging and discharging circuit. The pre-charging circuit is connected in parallel to the isolating switch.

[0005] In the technical solution of the embodiment of the present application, the positive output terminal of the battery device is usually a high potential terminal. During the charging and discharging process, the battery device has a large charge and discharge current due to a large voltage difference, and the pre-charging circuit is used for pre-charging and shunting to improve the reliability and stability of the charging and discharging circuit. In addition, the pre-charging circuit usually relies on an isolating switch. The pre-charging circuit is connected in parallel to the isolating switch. During the pre-charging process, the pre-charging circuit does not rely on the isolating switch, which can reduce the failure risk of the isolating switch.

[0006] In some embodiments, the first branch of the two side branches of the load is connected to the main positive relay, and the other first branch is connected to the main negative relay, and the main positive relay is connected to the positive output terminal of the battery device, and the main negative relay is connected to the negative output terminal of the battery device.

[0007] In some embodiments, the isolating switch includes a first isolating switch and a second isolating switch, the main positive relay and the first isolating switch are connected in series on the first branch, the main negative relay and the second isolating switch are connected in series on the second branch, and the pre-charging circuit includes a first pre-charging circuit and a second pre-charging circuit, the first pre-charging circuit is connected in parallel with the first isolating switch, and the second pre-charging circuit is connected in parallel with the second isolating switch.

[0008] In the technical solution of the embodiment of the present application, a first pre-charging circuit and a second pre-charging circuit are respectively connected in parallel on two isolating switches. The isolating switches are disconnected during the pre-charging process. If the isolating switches are short-circuited, the charging and discharging circuits can still be pre-charged. If either the first isolating switch or the second isolating switch is short-circuited, pre-charging can be performed through the other isolating switch, which can reduce the failure risk of the pre-charging circuit while improving the reliability and stability of the charging and discharging circuit.

[0009] In some embodiments, the pre-charging circuit further includes a third pre-charging circuit, and the third pre-charging circuit is connected in parallel with the main positive relay.

[0010] In the technical solution of the embodiment of the present application, the charge-discharge circuit can still be pre-charged when any pre-charge circuit is open or short-circuited, which can improve the reliability and stability of the charge-discharge circuit. In addition, the pre-charge circuit is arranged in parallel with the isolating switch, which can reduce the failure risk of the isolating switch.

[0011] In some embodiments, the pre-charging circuit further includes a fourth pre-charging circuit, and the fourth pre-charging circuit is connected in parallel with the main negative relay.

[0012] In the technical solution of the embodiment of the present application, the charge-discharge circuit can still be pre-charged when any pre-charge circuit is open or short-circuited, which can improve the reliability and stability of the charge-discharge circuit. In addition, the pre-charge circuit is arranged in parallel with the isolating switch, which can reduce the failure risk of the isolating switch.

[0013] In some embodiments, the pre-charging circuit includes a pre-charging relay and a pre-charging resistor, wherein the pre-charging relay and the pre-charging resistor are connected in series.

[0014] In some embodiments, the first isolating switch and the second isolating switch are configured to be disconnected when the charge-discharge circuit needs to be pre-charged, and the main positive relay, the main negative relay and the pre-charge relay are configured to be closed when the charge-discharge circuit needs to be pre-charged.

[0015] In some embodiments, the pre-charging relay is configured to be opened when the pre-charging of the charge-discharge circuit is completed, and the first isolation switch and the second isolation switch are configured to be closed when the pre-charging of the charge-discharge circuit is completed.

[0016] In some embodiments, the first isolation switch is configured to close when the first pre-charging circuit is open.

[0017] In the technical solution of the embodiment of the present application, when a short circuit occurs in the first pre-charging circuit, the first isolating switch connected in parallel with the first pre-charging circuit is closed. At this time, during the pre-charging process, the second pre-charging circuit is pre-charged, which can reduce the failure risk of the isolating switch while improving the reliability and stability of the charging and discharging circuit.

[0018] In some embodiments, the load includes a power conversion system (PCS) bus capacitor and a power conversion module, and the power conversion module bus capacitor and the power conversion module are connected in parallel.

[0019] In the technical solution of the embodiment of the present application, the bus capacitor of the power conversion module is connected in parallel with the power conversion module to smooth the battery output current, reduce voltage fluctuations, and improve the response speed of the system. The bus capacitor of the power conversion module provides instantaneous current demand when the power conversion module performs power conversion.

[0020] In some embodiments, the charge and discharge circuit further includes a plurality of high temperature fuses, each branch on both sides of the load is connected in series with a corresponding high temperature fuse of the plurality of high temperature fuses, and the plurality of high temperature fuses are used to protect the charge and discharge circuit.

[0021] In the technical solution of the embodiment of the present application, a plurality of high-temperature fuses are connected in series in the charging and discharging circuit to protect the charging and discharging circuit.

[0022] In a second aspect, the present application provides an energy storage system, comprising a power conversion module and a charge-discharge circuit as described in any one of the first aspects, wherein the charge-discharge circuit is used to charge and discharge the power conversion module. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A partial structural schematic diagram of a battery device according to an embodiment of the present application is shown.

[0024] Figure 2 A schematic structural diagram of a charging and discharging circuit provided in an embodiment of the present application is shown.

[0025] Figure 3 A structural schematic diagram of another charging and discharging circuit provided in an embodiment of the present application is shown.

[0026] Figure 4 A structural schematic diagram of another charging and discharging circuit provided in an embodiment of the present application is shown.

[0027] Figure 5 A structural schematic diagram of another charging and discharging circuit provided in an embodiment of the present application is shown.

[0028] Figure 6 A structural schematic diagram of another charging and discharging circuit provided in an embodiment of the present application is shown.

[0029] Figure 7 A structural schematic diagram of another charging and discharging circuit provided in an embodiment of the present application is shown.

[0030] Figure numerals: battery device 10, battery cell 12, first box body 111, second box body 112, charge and discharge circuit 20, main positive relay 21, main negative relay 22, isolating switch 23, first isolating switch 231, second isolating switch 232, pre-charging circuit 24, first pre-charging circuit 241, second pre-charging circuit 242, third pre-charging circuit 243, fourth pre-charging circuit 244, pre-charging relay 2411, pre-charging resistor 2412, load 25, power conversion module bus capacitor 251, power conversion module 252, high-temperature fuse 26, box body 11. DETAILED DESCRIPTION

[0031] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0033] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0034] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0035] The term "multiple" as used in the present application refers to more than two (including two). Similarly, the term "multiple groups" refers to more than two groups (including two groups), and the term "multiple sheets" refers to more than two sheets (including two sheets).

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0037] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0038] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, it is mentioned that the method may also include step (c), which means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0039] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, in parallel or in mixed connection through a busbar component.

[0040] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells.

[0041] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0042] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0043] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0044] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0045] As an example, the box may include a first box and a second box. The first box and the second box are buckled together to form a closed space inside the box to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0046] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0047] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0048] The embodiment of the present application provides an energy storage device, including one or more battery clusters (Battery Cluster) to increase the voltage and capacity of the energy storage device. The battery cluster may include multiple battery devices, and the multiple battery devices are connected in series through a busbar component to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0049] The energy storage device can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems or temporary power supply systems. The energy storage device can store electrical energy as needed and output electrical energy at an appropriate time. For example, the energy storage device can store electrical energy during low power consumption and provide electrical energy to relevant users or electrical equipment during peak power consumption. The energy storage system provided in the embodiment of the present application can be any power system that requires the use of an energy storage device.

[0050] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0051] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters, wherein the battery clusters are housed in the cabinet.

[0052] In some embodiments, the energy storage device may include modules such as a thermal management module, a main control module, a master control module, a power distribution module, and a fire protection module.

[0053] As an example, the thermal management module may include a liquid cooling unit that provides cooling liquid for regulating the temperature of the battery cells to each battery device through a pipeline.

[0054] As an example, the main control module can be used as a battery management unit of a battery cluster to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power or temperature of the battery cluster. For example, the charging and discharging current and voltage of the battery cluster can be controlled. The main control module includes a slave battery management unit SBMU (Slave Battery Management Unit, SBMU), a fusion switch and other modules.

[0055] As an example, the master control module can be used as a battery management unit of an energy storage device to monitor and manage the energy storage device. The master control module can monitor information such as the current, voltage, power, state of charge or temperature of the energy storage device. For example, the charging and discharging current, voltage, etc. of the energy storage device can be controlled. As an example, the master control module includes an insulation monitoring module IMM (Insulation Monitoring Module, abbreviated as IMM), a master battery management unit MBMU (Master Battery Management Unit, MBMU), Ethernet ETH (EtherNet, ETH) and a fiber optic conversion module.

[0056] As an example, the fire protection system includes a control panel, detectors, alarm devices, etc., which are used to detect, alarm or extinguish fire in the energy storage system.

[0057] As an example, the power distribution device may be used to distribute power to the power modules of the energy storage device.

[0058] In some embodiments, the energy storage system may include one or more energy storage devices and a power conversion device, wherein the power conversion device is used to connect between the power generation device and the energy storage device. The power generation device is used to generate electrical energy, and the electrical energy generated by the power generation device can be stored in the energy storage device through the power conversion device. As an example, the power generation device may specifically be a solar panel, a hydroelectric power generation device, a thermal power generation device, a wind power generation device, etc. The specific type of the power generation device is not limited in this application.

[0059] With the development of energy storage technology, energy storage systems are required to operate stably under various conditions to ensure the continuity and stability of the power system. This requires that the energy storage system has high reliability, can maintain long-term stable operation under various environments, and has a low failure rate and maintenance cost. In the charging and discharging circuit of the energy storage system, the battery device has excessive charging and discharging current due to the large voltage difference. Excessive charging and discharging current will cause damage to electrical components or affect the service life of the battery cell. Usually, a pre-charging circuit is connected in parallel to the main positive relay for shunting to improve the high reliability of the charging and discharging circuit.

[0060] The pre-charging circuit can be connected in parallel with the charging and discharging circuit for pre-charging, and the shunt protection circuit can be implemented. However, for the isolating switch in the charging and discharging circuit, if a short circuit or open circuit occurs during the charging and discharging process, the pre-charging process will fail. Therefore, it is worth considering how to reduce the failure risk of the isolating switch while improving the reliability and stability of the charging and discharging circuit.

[0061] In order to alleviate the above problems, the pre-charging circuit can be connected in parallel to the isolating switch. During the pre-charging process of the pre-charging circuit, the isolating switch is disconnected. Therefore, the pre-charging process is not related to the isolating switch, which can reduce the failure risk of the isolating switch. At the same time, the pre-charging process of the pre-charging circuit can improve the reliability and stability of the charging and discharging circuit.

[0062] Based on the above considerations, the present application proposes a charge-discharge circuit, including a main positive relay, a main negative relay, an isolating switch, a pre-charge circuit and a load, wherein the main positive relay, the isolating switch, the main negative relay and the load are connected in series, and the pre-charge circuit is used to adjust the charge-discharge current of the charge-discharge circuit, and the pre-charge circuit is connected in parallel to the isolating switch. This can reduce the failure risk of the isolating switch while improving the reliability and stability of the charge-discharge circuit.

[0063] Figure 1 FIG. 1 is a schematic diagram showing a partial structure of a battery device 10 according to an embodiment of the present application. Figure 1 As shown, the battery device 10 of the embodiment of the present application may include a plurality of battery cells 12 to meet different power requirements. The shape of the battery cell 12 of the embodiment of the present application may be set according to the actual application. For example, the battery cell 12 may be as follows: Figure 1 The cylindrical shape shown, or it can also be different from Figure 1 The rectangular parallelepiped or other shapes shown are not limited to the embodiments of the present application.

[0064] It should be understood that Figure 1 As shown, the battery device 10 of the embodiment of the present application may further include a box body 11, which may be used to accommodate a plurality of battery cells 12. The interior of the box body 11 of the embodiment of the present application is a hollow structure, and a plurality of battery cells 12 are accommodated in the box body 11. The box body 11 may include two parts, which are respectively referred to as a first box body part 111 and a second box body part 112, and the first box body part 111 and the second box body part 112 are buckled together. The shapes of the first box body part 111 and the second box body part 112 may be determined according to the shapes of the components accommodated inside. For example, they may be determined according to the shape of the combination of the plurality of battery cells 12 accommodated inside. At least one of the first box body part 111 and the second box body part 112 has an opening. For example, as Figure 1As shown, the first box body 111 and the second box body 112 can both be hollow cuboids and each have an open face, the opening of the first box body 111 and the opening of the second box body 112 are arranged opposite to each other, and the first box body 111 and the second box body 112 are buckled together to form a box body 11 with a closed chamber, which can be used to accommodate multiple battery cells 12. Multiple battery cells 12 are connected in parallel, in series, or in mixed combination and placed in the box body 11 formed by the first box body 111 and the second box body 112 buckled together.

[0065] For example, different from Figure 1 As shown, only one of the first box body 111 and the second box body 112 may be a hollow cuboid with an opening, while the other is in a plate shape to cover the opening. Taking the second box body 112 as a hollow cuboid with an opening and the first box body 111 as a plate, the first box body 111 covers the opening of the second box body 112 to form a box body 11 with a closed chamber, which can be used to accommodate multiple battery cells 12.

[0066] Figure 2 A schematic structural diagram of a charge and discharge circuit 20 provided in an embodiment of the present application is shown.

[0067] According to some embodiments of the present application, referring to Figure 2 The present application provides a charging and discharging circuit 20, including a main positive relay 21, a main negative relay 22, an isolating switch 23, a pre-charging circuit 24 and a load 25. The main positive relay 21, the isolating switch 23, the main negative relay 22 and the load 25 are connected in series. The pre-charging circuit 24 is used to adjust the charging and discharging current of the charging and discharging circuit 20, and the pre-charging circuit 24 is connected in parallel to the isolating switch 23.

[0068] The main positive relay 21 can be a switch. When the main positive relay 21 is closed, the charge-discharge circuit 20 starts to charge and discharge. When the main positive relay 21 is disconnected, the charge-discharge circuit 20 is disconnected. Similar to the main positive relay 21, when the main negative relay 22 is closed, the charge-discharge circuit 20 starts to charge and discharge. When the main negative relay 22 is disconnected, the charge-discharge circuit 20 is disconnected.

[0069] In addition, the main positive relay 21, the isolating switch 23, the main negative relay 22 and the load 25 can be connected in series to the battery device 10, wherein the positive output terminal of the battery device 10 is usually a high potential terminal. During the charging and discharging process, the battery device 10 has a large voltage difference, which causes the charging and discharging current to be too large. The pre-charging circuit 24 is used for pre-charging and shunting, thereby improving the reliability and stability of the charging and discharging circuit 20. Usually, the pre-charging circuit 24 depends on the isolating switch 23, and the pre-charging circuit 24 is connected in parallel to the isolating switch 23. The isolating switch is disconnected during the pre-charging process. Therefore, the pre-charging circuit 24 does not rely on the isolating switch 23 during the pre-charging process, thereby reducing the failure risk of the isolating switch 23.

[0070] According to some embodiments of the present application, optionally, reference Figure 2 The first branch of the two side branches of the load 25 is connected to the main positive relay 21, and the second branch is connected to the main negative relay 22. The main positive relay 21 is connected to the positive output terminal of the battery device 10, and the main negative relay 22 is connected to the negative output terminal of the battery device 10.

[0071] It should be understood that the isolating switch 23 can be one or two. In the case of one, it can be connected in series to the branch on either side of the load 25. In the case of two, it can be connected in series to the branch on either side of the load 25, or it can be connected in series to the branches on both sides respectively. The present application does not impose any limitation on this.

[0072] Figure 3 A structural schematic diagram of another charging and discharging circuit 20 provided in an embodiment of the present application is shown.

[0073] According to some embodiments of the present application, optionally, reference Figure 3 The isolating switch 23 includes a first isolating switch 231 and a second isolating switch 232. The main positive relay 21 and the first isolating switch 231 are connected in series on the first branch. The main negative relay 22 and the second isolating switch 232 are connected in series on the second branch. The pre-charging circuit 24 includes a first pre-charging circuit 241 and a second pre-charging circuit 242. The first pre-charging circuit 241 is connected in parallel with the first isolating switch 231, and the second pre-charging circuit 242 is connected in parallel with the second isolating switch 232.

[0074] In the charge and discharge circuit 20, the first pre-charging circuit 241 and the second pre-charging circuit 242 are respectively connected in parallel on the two isolating switches 23. The isolating switch 23 is disconnected during the pre-charging process. If the isolating switch 23 is short-circuited, the charge and discharge circuit 20 can still be pre-charged. When any of the first isolating switch 231 and the second isolating switch 232 is short-circuited, pre-charging can be performed through the other isolating switch 23, which can reduce the failure risk of the pre-charging circuit 24 while improving the reliability and stability of the charge and discharge circuit.

[0075] For example, Figure 3 As shown, in the case where the first isolating switch 231 is short-circuited, the first pre-charging circuit 241 fails, and during the pre-charging process, the current in the battery device 10 flows from the main positive relay 21, the first isolating switch 231, the load 25, the second pre-charging circuit 242, and the main negative relay 22 to the battery device 10. Therefore, in the case of two pre-charging circuits 24, if one of them is short-circuited or disconnected, the pre-charging process is not affected, and the reliability and stability of the charge and discharge circuit 20 can be improved.

[0076] Figure 4 A schematic structural diagram of another charging and discharging circuit 20 provided in an embodiment of the present application is shown.

[0077] According to some embodiments of the present application, optionally, reference Figure 4 The pre-filling circuit 24 also includes a third pre-filling circuit 243 , and the third pre-filling circuit 243 is connected in parallel with the main positive relay 21 .

[0078] like Figure 4 As shown, there can be three pre-charging circuits 24, which are respectively connected in parallel in the first isolating switch 231, the second isolating switch 232 and the main positive relay 21. For example, when the first isolating switch 231 and the second isolating switch 232 are short-circuited, pre-charging can be performed through the third pre-charging circuit 243. For another example, when the first isolating switch 231 and the main positive relay 21 are short-circuited, pre-charging can be performed through the second pre-charging circuit 242. For another example, when the first isolating switch 231 is short-circuited, pre-charging can be performed through the second pre-charging circuit 242 and the third pre-charging circuit 243. This redundant design can reduce the failure risk of the isolating switch 23 while improving the reliability and stability of the charge and discharge circuit 20.

[0079] Figure 5 A structural schematic diagram of another charging and discharging circuit 20 provided in an embodiment of the present application is shown.

[0080] According to some embodiments of the present application, optionally, reference Figure 5The pre-filling circuit 24 also includes a fourth pre-filling circuit 244 , and the fourth pre-filling circuit 244 is connected in parallel with the main negative relay 22 .

[0081] like Figure 5 As shown, there can be four pre-charging circuits 24, which are respectively connected in parallel in the first isolating switch 231, the second isolating switch 232, the main positive relay 21 and the main negative relay 22. For example, when the first isolating switch 231 and the second isolating switch 232 are short-circuited, pre-charging can be performed through the third pre-charging circuit 243 and the fourth pre-charging circuit 244. For another example, when the first isolating switch 231 and the main positive relay 21 are short-circuited, pre-charging can be performed through the second pre-charging circuit 242 and the fourth pre-charging circuit 244. For another example, when the first isolating switch 231 is short-circuited, pre-charging can be performed through the second pre-charging circuit 242, the fourth pre-charging circuit 244 and the third pre-charging circuit 243. For another example, when the first isolating switch 231, the second isolating switch 232 and the main positive relay 21 are short-circuited, pre-charging can be performed through the fourth pre-charging circuit 24. This redundant design can reduce the failure risk of the isolating switch 23 while improving the reliability and stability of the charging and discharging circuit 20.

[0082] According to some embodiments of the present application, optionally, reference may be made to Figures 2 to 5 The pre-charging circuit 24 includes a pre-charging relay 2411 and a pre-charging resistor 2412, wherein the pre-charging relay 2411 and the pre-charging resistor 2412 are connected in series.

[0083] The pre-charge relay 2411 slowly builds up the power supply voltage through delay at the moment of power-on, preventing the power supply voltage from being suddenly added to the load 25, causing excessive impact current. The pre-charge relay 2411 can limit the size of the initial current by controlling the pre-charge time, thereby protecting the devices in the charge-discharge circuit 20 from damage due to excessive current.

[0084] The pre-charging resistor 2412 plays a current limiting role in the pre-charging process, and it protects the load 25 and the power supply by limiting the maximum current flowing through the load 25. In addition, in the pre-charging stage, the pre-charging resistor 2412 and the capacitor in the load 25 form an RC (resistance-capacitance) network to build up the voltage across the capacitor step by step to prevent voltage mutation.

[0085] Figure 6 A schematic structural diagram of another charging and discharging circuit 20 provided in an embodiment of the present application is shown.

[0086] Optional, you can refer to Figure 6The isolating switch 23 includes a first isolating switch 231 and a second isolating switch 232, the main positive relay 21 and the first isolating switch 231 are connected in series, the main negative relay 22 and the second isolating switch 232 are connected in series, and the pre-charging circuit 24 includes a first pre-charging circuit 241 and a second pre-charging circuit 242, the first pre-charging circuit 241 is connected in parallel with the main positive relay 21, and the second pre-charging circuit 242 is connected in parallel with the main negative relay 22.

[0087] like Figure 6 As shown, there can be two pre-charging circuits 24, which are respectively connected in parallel in the main positive relay 21 and the main negative relay 22. For example, when the main positive relay 21 is short-circuited, pre-charging can be performed through the second pre-charging circuit 242. For another example, when the main negative relay 22 is short-circuited, pre-charging can be performed through the second pre-charging circuit 242. This redundant design can reduce the failure risk of the isolating switch 23 while improving the reliability and stability of the charging and discharging circuit 20.

[0088] According to some embodiments of the present application, optionally, reference may be made to Figures 2 to 6 The first isolating switch 231 and the second isolating switch 232 are configured to be disconnected when the charge-discharge circuit 20 needs to be pre-charged, and the main positive relay 21, the main negative relay 22 and the pre-charge relay 2411 are configured to be closed when the charge-discharge circuit 20 needs to be pre-charged.

[0089] like Figure 3 As shown, there can be two pre-charging circuits 24, which are respectively connected in parallel to the first isolating switch 231 and the second isolating switch 232. During the pre-charging process of the charge and discharge circuit 20, the first isolating switch 231 and the second isolating switch 232 are disconnected, and the main positive relay 21, the main negative relay 22 and the pre-charging relay 2411 are closed to form a circuit for pre-charging.

[0090] It should be understood that when there are three or four pre-filling circuits 24, during the pre-filling process, the device connected in parallel with the pre-filling circuit 24 is disconnected, and the pre-filling circuit 24 and other components are closed to form a circuit for pre-filling. Figure 4 As shown, during the pre-charging process, the main positive relay 21, the first isolating switch 231 and the second isolating switch 232 are disconnected, and the pre-charging loop 24 and the main negative relay 22 are closed to form a loop for pre-charging.

[0091] According to some embodiments of the present application, optionally, reference may be made to Figures 2 to 6 The pre-charging relay 2411 is configured to be disconnected when the pre-charging of the charging and discharging circuit 20 is completed, and the first isolating switch 231 and the second isolating switch 232 are configured to be closed when the pre-charging of the charging and discharging circuit 20 is completed.

[0092] After the pre-charging is completed, the charge-discharge circuit 20 starts to work for normal charge and discharge, the pre-charging loop 24 is disconnected, and the first isolating switch 231 and the second isolating switch 232 are closed for normal charge and discharge.

[0093] It should be understood that when there are three or four pre-charging circuits 24, when normal charging and discharging are performed after the pre-charging is completed, all the pre-charging circuits 24 are disconnected, and the main positive relay 21, the main negative relay 22, and the first isolating switch 231 and the second isolating switch 232 are closed for normal charging and discharging.

[0094] According to some embodiments of the present application, optionally, reference may be made to Figures 2 to 6 The first isolation switch 231 is configured to be closed when the first pre-charging circuit 241 is open.

[0095] When the first pre-charging circuit 241 is broken, the first isolating switch 231 connected in parallel with the first pre-charging circuit 241 is closed. During the pre-charging process, the second pre-charging circuit 242 is pre-charged, which can reduce the failure risk of the isolating switch 23 and improve the reliability and stability of the charge and discharge circuit 20.

[0096] It should be understood that when the pre-filling circuit 24 includes three or four circuits, if any one of the pre-filling circuits 24 is disconnected, the corresponding component is closed to perform normal pre-filling. For example, when the pre-filling circuit 24 includes three circuits, Figure 3 As shown, when the first pre-filling circuit 241 and the second pre-filling circuit 242 are broken, the first isolating switch 231 and the second isolating switch 232 are closed, and the third pre-filling circuit 243 is connected to the first isolating switch 231 and the second isolating switch 232 for pre-filling.

[0097] Figure 7 A structural schematic diagram of another charging and discharging circuit 20 provided in an embodiment of the present application is shown.

[0098] According to some embodiments of the present application, optionally, reference Figure 7 The load 25 includes a power conversion module bus capacitor 251 and a power conversion module 252, and the power conversion module bus capacitor 251 and the power conversion module 252 are connected in parallel.

[0099] The bus capacitor 251 of the power conversion module is connected in parallel with the power conversion module 252 to smooth the battery output current, reduce voltage fluctuations, and improve the response speed of the system. The bus capacitor 251 of the power conversion module provides instantaneous current demand when the power conversion module 252 performs power conversion.

[0100] The bus capacitor 251 of the power conversion module is responsible for converting the direct current of the battery into alternating current and supplying it to the power grid, or receiving alternating current from the power grid and converting it into direct current and storing it in the battery device 10 .

[0101] The working process of the charge and discharge circuit 20 is as follows: the charge and discharge circuit 20 includes two pre-charging circuits 24 and is connected in parallel to the isolating switch 23 for pre-charging. The first isolating switch 231 and the second isolating switch 232 are both in the disconnected state, the battery device 10 is isolated from the load 25, and the load 25 is charged through the first pre-charging circuit 241 and the second pre-charging circuit 242 to avoid the large current shock generated when the battery device 10 is directly connected. After the pre-charging is completed, the first isolating switch 231 and the second isolating switch 232 are closed, and the battery device 10 is directly connected to the load 25. When the charge and discharge circuit 20 needs to be shut down or maintained, the main positive relay 21 and the main negative relay 22 are disconnected, and the battery device 10 is completely isolated from the load 25, thereby improving the safety of the charge and discharge circuit 20.

[0102] According to some embodiments of the present application, optionally, reference may be made to Figures 2 to 7 The charging and discharging circuit 20 also includes a plurality of high-temperature fuses 26 . Each branch on both sides of the load 25 is connected in series with a corresponding high-temperature fuse 26 of the plurality of high-temperature fuses 26 . The plurality of high-temperature fuses 26 are used to protect the charging and discharging circuit 20 .

[0103] Among them, the high temperature fuse 26 can be connected in series in the charge and discharge circuit 20. For example, it can be connected in series between the battery device 10 and the main positive relay 21, or it can be connected in series between the battery device 10 and the main negative relay 22, or it can be connected in series between the battery devices 10, respectively, to protect the charge and discharge circuit 20, and this application does not make any restrictions on this. For example, in the case where the main positive relay 21 is stuck due to excessive temperature, the charge and discharge circuit 20 can be protected by the high temperature fuse 26 connected in series with the main positive relay 21.

[0104] According to some embodiments of the present application, the present application further provides an energy storage system, including a power conversion module and a charge and discharge circuit as in any of the above embodiments, wherein the charge and discharge circuit is used to charge and discharge the power conversion module.

[0105] According to some embodiments of the present application, see Figure 2 The present application provides a charge-discharge circuit 20, including a main positive relay 21, a main negative relay 22, an isolating switch 23, a pre-charge circuit 24 and a load 25. The main positive relay 21, the isolating switch 23, the main negative relay 22 and the load 25 are connected in series, and the pre-charge circuit 24 is used to adjust the charge-discharge current of the charge-discharge circuit 20. The pre-charge circuit 24 is connected in parallel to the isolating switch 23. The failure risk of the isolating switch 23 can be reduced while improving the reliability and stability of the charge-discharge circuit 20.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A charging and discharging circuit, characterized in that: The invention comprises a main positive relay (21), a main negative relay (22), an isolating switch (23), a pre-charging circuit (24) and a load (25), wherein the main positive relay (21), the isolating switch (23), the main negative relay (22) and the load (25) are connected in series. The pre-charging circuit (24) is used to adjust the charging and discharging current of the charging and discharging circuit, and the pre-charging circuit (24) is connected in parallel to the isolating switch (23).

2. The charge and discharge circuit according to claim 1, characterized in that: The first branch of the two side branches of the load (25) is connected to the main positive relay (21), and the second branch is connected to the main negative relay (22); the main positive relay (21) is connected to the positive output terminal of the battery device (10), and the main negative relay (22) is connected to the negative output terminal of the battery device (10).

3. The charge and discharge circuit according to claim 2, characterized in that: The isolating switch (23) comprises a first isolating switch (231) and a second isolating switch (232), the main positive relay (21) and the first isolating switch (231) are connected in series on the first branch, and the main negative relay (22) and the second isolating switch (232) are connected in series on the second branch. The pre-filling circuit (24) comprises a first pre-filling circuit (241) and a second pre-filling circuit (242); the first pre-filling circuit (241) is connected in parallel with the first isolating switch (231); and the second pre-filling circuit (242) is connected in parallel with the second isolating switch (232).

4. The charge and discharge circuit according to claim 3, characterized in that: The pre-filling circuit (24) further comprises a third pre-filling circuit (243), The third pre-charging circuit (243) is connected in parallel with the main positive relay (21).

5. The charge and discharge circuit according to claim 4, characterized in that: The pre-filling circuit (24) further comprises a fourth pre-filling circuit (244), The fourth pre-charging circuit (244) is connected in parallel with the main negative relay (22).

6. The charge and discharge circuit according to any one of claims 3 to 5, characterized in that: The pre-charging circuit (24) comprises a pre-charging relay (2411) and a pre-charging resistor (2412). Wherein, the pre-charging relay (2411) and the pre-charging resistor (2412) are connected in series.

7. The charge and discharge circuit according to claim 6, characterized in that: The first isolating switch (231) and the second isolating switch (232) are configured to be disconnected when the charge-discharge circuit needs to be pre-charged. The main positive relay (21), the main negative relay (22), and the pre-charging relay (2411) are configured to be closed when the charging and discharging circuit needs to be pre-charged.

8. The charge and discharge circuit according to claim 7, characterized in that: The pre-charging relay (2411) is configured to be disconnected when the pre-charging of the charge-discharge circuit is completed. The first isolating switch (231) and the second isolating switch (232) are configured to be closed when pre-charging of the charge-discharge circuit is completed.

9. The charge and discharge circuit according to claim 7, characterized in that: The first isolation switch (231) is configured to be closed when the first pre-charging circuit (241) is disconnected.

10. The charge and discharge circuit according to any one of claims 3 to 5, characterized in that: The load (25) comprises a power conversion module bus capacitor (251) and a power conversion module (252), and the power conversion module bus capacitor (251) and the power conversion module (252) are connected in parallel.

11. The charge and discharge circuit according to any one of claims 2 to 5, characterized in that: The charging and discharging circuit further comprises a plurality of high-temperature fuses (26), each branch of the two side branches of the load (25) being connected in series with a corresponding one of the plurality of high-temperature fuses (26). The plurality of high-temperature fuses (26) are used to protect the charging and discharging circuit.

12. An energy storage system, characterized in that: It comprises a power conversion module and a charge-discharge circuit as claimed in any one of claims 1 to 11, wherein the charge-discharge circuit is used for charging and discharging the power conversion module.

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