Battery pack, grid connection management method, electric energy device and energy storage system

Abstract

A battery pack (100), comprising a battery (1), an on-board charger (2), an alternating-current interface (3) and a battery management system (4), wherein the battery (1) is used for providing a direct current; the battery (1) is connected to the alternating-current interface (3) by means of the on-board charger (2); the on-board charger (2) is used for converting the direct current of the battery (1) into an alternating current, or converting into a direct current an alternating current transmitted by the alternating-current interface (3); the battery management system (4) is connected to the battery (1) and the on-board charger (2); and the battery management system (4) is used for controlling, when a discharging signal is received, the current of the battery (1) to flow to a current network (300) via the on-board charger (2) and the alternating-current interface (3), and for controlling, when a charging signal is received, the current of the battery (1) to flow to the battery via the alternating-current interface (3) and the on-board charger (2).

Description

Battery packs, grid connection management methods, power equipment, and energy storage systems

[0001] Priority information

[0002] This application claims priority and benefit to patent application No. 202410870637X, filed with the China National Intellectual Property Administration on June 28, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery pack technology, and in particular to a battery pack, a grid connection management method, an electrical energy device, and an energy storage system. Background Technology

[0004] During vehicle use, the performance of power batteries gradually degrades. Typically, when the battery capacity decays to below 80% of its initial capacity, the power battery is retired. Although these retired power batteries can no longer meet the high energy demand of applications such as automobiles, their remaining capacity can still meet the requirements of low energy demand scenarios such as energy storage and backup power. Therefore, retired power batteries are usually sent to energy storage systems and reused as energy storage devices; this process is also known as the secondary use of battery packs.

[0005] However, due to the differences in voltage platforms of power batteries produced by different manufacturers and in different vehicle models, different power batteries require different power storage inverters (PCS) to transfer current between the power battery and the energy storage station when connected to the grid. This increases the grid connection cost between the power battery and the energy storage station. Summary of the Invention

[0006] The purpose of this application is to provide a battery pack, a grid connection management method, an electrical energy device, and an energy storage system, aiming to solve the problem in related technologies that the battery pack cannot be directly connected to the grid of an energy storage power station.

[0007] To achieve the objectives of this application, in a first aspect, this application provides a battery pack, the battery pack including a battery, an on-board charger, an AC interface, and a battery management system, wherein the battery is used to provide DC current;

[0008] The battery is connected to the AC interface via the on-board charger; the on-board charger is used to convert the DC current of the battery into AC current, or to convert the AC current transmitted through the AC interface into DC current.

[0009] The battery management system is connected to the battery and the on-board charger. When a discharge signal is received, the battery management system controls the current of the battery to flow to the current network through the on-board charger and the AC interface; when a charging signal is received, the battery current controls the current of the battery to flow to the battery through the AC interface and the on-board charger.

[0010] In one possible implementation, the battery pack further includes a first power interface connected to the battery management system, the first power interface being used to receive the discharge signal and the charging signal.

[0011] In one possible implementation, the battery pack further includes a first switch module, a second switch module, and a second power interface;

[0012] The first switch module and the second switch module are connected between the battery, the second power interface and the on-board charger, so that a current loop is formed between the battery, the second power interface and the on-board charger.

[0013] In one possible implementation, the first end of the first switch module is connected to the battery, and the second end of the first switch module is connected to the second power interface and the first end of the second switch module.

[0014] The second terminal of the second switch module is connected to the on-board charger.

[0015] In one possible implementation, a first end of the first switch module is connected to the battery, and a second end of the first switch module is connected to the second power interface.

[0016] The first end of the second switch module is connected to the battery, and the second end of the second switch module is connected to the on-board charger.

[0017] In one possible implementation, a first end of the first switch module is connected to the battery, and a second end of the first switch module is connected to the on-board charger and the first end of the second switch module.

[0018] The second end of the second switch module is connected to the first power interface.

[0019] In one possible implementation, the battery pack further includes a third switch module connected between the on-board charger and the AC interface.

[0020] Secondly, this application also proposes a grid-connected management method, which is applied to a battery pack. The battery pack includes a battery, an on-board charger, an AC interface, and a battery management system. The battery is connected to the AC interface via the on-board charger, and the battery management system is connected to both the battery and the on-board charger. The grid-connected management method includes:

[0021] When the battery management system receives a discharge signal, it controls the current of the battery to flow to the current network through the on-board charger and AC interface to supply power to the current network.

[0022] When the battery management system receives a charging signal, it controls the current of the battery to flow to the battery through the AC interface and the on-board charger to charge the battery.

[0023] In one possible implementation, the battery pack further includes a first power interface connected to the battery management system.

[0024] The battery management system receives the discharge signal and the charging signal through the first power interface.

[0025] In one possible implementation, the battery pack further includes a first switch module and a third switch module, the third switch module being connected between the on-board charger and the AC interface, and the first switch module being connected between the battery and the on-board charger;

[0026] The battery management system controls the flow of current from the battery to the current network via the on-board charger and AC interface, including the following steps:

[0027] The battery management system controls the closing of the first switch module and the third switch module;

[0028] The battery management system controls the on-board charger to enter a first working mode. In the first working mode, the current in the on-board charger is only allowed to flow in the direction from the battery to the AC interface.

[0029] In one possible implementation, the battery pack further includes a first switch module and a third switch module, the third switch module being connected between the on-board charger and the AC interface, and the first switch module being connected between the battery and the on-board charger;

[0030] The battery management system controls the flow of current from the battery to the battery via the AC interface and the on-board charger, including the following steps:

[0031] The battery management system controls the closing of the first switch module and the third switch module;

[0032] The battery management system controls the on-board charger to enter a second operating mode. In the second operating mode, the current in the on-board charger is only allowed to flow along the AC interface towards the battery.

[0033] In one possible implementation, the battery pack stops supplying power to the current network when at least one of the following conditions is met:

[0034] Received a discharge stop signal; or

[0035] The battery pack has reached the discharge cutoff condition; or

[0036] The battery pack has reached the end of its battery life; or

[0037] The battery pack has a circuit fault.

[0038] In one possible implementation, the battery pack stops charging when at least one of the following conditions is met:

[0039] Received a charging stop signal; or

[0040] The battery pack has reached the charging cutoff condition; or

[0041] The battery pack has reached the end of its battery life; or

[0042] The battery pack has a circuit fault.

[0043] In one possible implementation, the grid connection management method further includes:

[0044] When the battery pack meets the off-grid conditions, disconnect the current connection between the battery and the on-board charger, as well as between the on-board charger and the AC interface.

[0045] In one possible implementation, the off-grid conditions include at least one of the following:

[0046] Received off-grid signal; or

[0047] The battery pack has reached the charging cutoff condition or the battery pack has reached the discharging cutoff condition; or

[0048] The battery pack's battery life has ended;

[0049] The battery pack has a circuit fault.

[0050] Thirdly, this application also proposes an electrical energy device, which includes an electrical component and a battery pack electrically connected to the electrical component. The battery pack includes a battery, an on-board charger, an AC interface, and a battery management system. The battery is used to provide direct current.

[0051] The battery is connected to the AC interface via the on-board charger; the on-board charger is used to convert the DC current of the battery into AC current, or to convert the AC current transmitted through the AC interface into DC current.

[0052] The battery management system is connected to the battery and the on-board charger. When a discharge signal is received, the battery management system controls the current of the battery to flow to the current network through the on-board charger and the AC interface; when a charging signal is received, the battery current controls the current of the battery to flow to the battery through the AC interface and the on-board charger.

[0053] Fourthly, this application also proposes an energy storage system, the energy storage system comprising:

[0054] Current network;

[0055] A battery pack, the battery pack being connected to the current network;

[0056] A controller, which is electrically connected to the battery pack.

[0057] This application's technical solution integrates an on-board charger (OBC) into the battery pack. When the battery pack is in normal service, the OBC converts the AC power from the grid into DC power usable by the battery pack after the power equipment is connected to the grid, thus charging the battery pack. When the battery pack is decommissioned, the OBC can replace the energy storage inverter, converting the AC / DC communication protocol between the battery pack and the energy storage power station, thereby solving the problem that different battery packs require different energy storage inverters to connect to the energy storage power station.

[0058] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0059] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:

[0060] Figure 1 is a schematic diagram of an embodiment of the energy storage system provided in this application;

[0061] Figure 2 is a schematic diagram of the battery pack in Figure 1;

[0062] Figure 3 is a structural schematic diagram of the first embodiment of the connection between the battery, on-board charger and second power interface in Figure 2;

[0063] Figure 4 is a structural schematic diagram of the second embodiment in which the battery, on-board charger and second power interface are connected in Figure 2;

[0064] Figure 5 is a structural schematic diagram of the third embodiment in which the battery, on-board charger and second power interface are connected in Figure 2;

[0065] Figure 6 is a flowchart illustrating the first embodiment of the grid connection management method provided in this application;

[0066] Figure 7 is a flowchart illustrating an embodiment of the grid-connected management method provided in this application, in which the battery pack supplies power to the current network.

[0067] Figure 8 is a schematic flowchart of an embodiment of the grid connection management method provided in this application, in which the current network charges the battery pack.

[0068] Figure 9 is a flowchart illustrating a second embodiment of the grid connection management method provided in this application.

[0069] Reference numerals: 1000-Energy storage system, 300-Current network, 200-Controller, 100-Battery pack; 1-Battery; 2-On-board charger, 3-AC interface, 4-Battery management system, 5-First power interface, 6-Second power interface, 7-First switch module, 8-Second switch module, 9-Third switch module. Detailed Implementation

[0070] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0071] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0072] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0073] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0074] This application proposes an electrical power device, which can be a vehicle, an aircraft, or a ship, and this application does not limit it in this regard.

[0075] For example, taking a vehicle as an example, when the battery pack is applied to a vehicle, according to the power source, the vehicle can be an electric vehicle, a gasoline vehicle, or a hybrid vehicle; this application does not limit this. According to the vehicle category, the vehicle can be a sedan, a truck, or a forklift; this application does not limit this.

[0076] The vehicle includes a body, electrical components, and a battery pack. The body serves as the supporting frame of the vehicle, providing support and connection for the various component assemblies. The electrical components are located on the body and can be motors, dashboards, window lift mechanisms, etc., which are not limited in this application.

[0077] The battery pack is housed within the vehicle body and electrically connected to the electrical devices. The battery pack stores power and supplies it to the electrical devices when needed, maintaining their normal operation.

[0078] During vehicle use, the performance of the battery pack gradually degrades. Typically, when the battery pack's capacity drops below 80% of its initial capacity, it can no longer meet the vehicle's requirements for high range and high power. At this point, vehicle maintenance personnel will replace the battery pack with a new one and "retire" the old one.

[0079] While retired battery packs can no longer meet the high energy demands of applications such as automobiles, their remaining capacity can still satisfy the requirements of low energy demand scenarios such as energy storage and backup power. Therefore, retired battery packs are usually put into energy storage systems.

[0080] Referring to Figure 1, this application also proposes an energy storage system 1000. When the battery pack 100 is applied to the energy storage system 1000, the energy storage system 1000 can be an energy storage power station or a household energy storage device; this application does not impose any limitations on this. Taking an energy storage power station as an example, the energy storage system 1000 includes a current network 300, a battery pack 100, and a controller 200. One end of the current network 300 is connected to the power generation equipment, and the other end is connected to each electrical load. The battery pack 100 is connected to the current network 300. When the power generation of the power generation equipment is greater than the power consumption of each electrical load, the battery pack 100 stores electricity. When the power generation of the power generation equipment is less than the power consumption of each electrical load, the battery pack 100 stores electricity. The controller 200 is electrically connected to the battery pack 100. The controller 200 can control the charging and discharging of the battery pack 100, thereby enabling the battery pack 100 to store electricity when there is surplus power generation from the power generation equipment and to release electricity when the power generation equipment is insufficient.

[0081] In related technologies, due to the differences in voltage platforms of battery packs 100 produced by different manufacturers and vehicle models, different energy storage inverters (PCS) are required to transfer the current between the battery pack 100 and the energy storage power station when different battery packs 100 are connected to the grid. This increases the grid connection cost between the battery pack 100 and the energy storage power station.

[0082] Please refer to Figure 2. To solve the above problems, in this application, the battery pack 100 includes a battery 1, an on-board charger 2 (OBC), an AC interface 3, and a battery management system 4. The battery 1 is used to provide direct current. The battery 1 is connected to the AC interface 3 through the on-board charger 2. The on-board charger 2 is used to convert the direct current of the battery 1 into AC current, or to convert the AC current transmitted through the AC interface 3 into direct current. The battery management system 4 is connected to the battery 1 and the on-board charger 2. When a discharge signal is received, the battery management system 4 controls the current of the battery 1 to flow to the current network 300 through the on-board charger 2 and the AC interface 3. When a charging signal is received, the battery management system 4 controls the current of the battery 1 to flow to the battery 1 through the AC interface 3 and the on-board charger 2.

[0083] The technical solution of this application integrates the on-board charger 2 into the battery pack 100. When the battery pack 100 is in normal service, the on-board charger 2 can convert the AC power from the grid into DC power usable by the batteries 1 of the battery pack 100 after the power equipment is connected to the grid, thereby charging the battery pack 100. When the battery pack 100 is decommissioned, the on-board charger 2 can replace the energy storage inverter to complete the AC / DC conversion and communication protocol conversion between the battery pack 100 and the energy storage power station, thus solving the problem that different battery packs 100 require different energy storage inverters to be connected to the energy storage power station.

[0084] The battery pack 100 provided in this application will now be described in detail with reference to the accompanying drawings.

[0085] The battery pack 100 includes a battery 1, which stores and releases electrical energy to power electrical devices or loads when needed. The battery 1 is formed by multiple cells connected in parallel or series. The voltage of the battery 1 is V, where 300V ≤ V ≤ 1000V.

[0086] The battery pack 100 also includes an AC interface 3 and an on-board charger 2. The AC interface 3 is used to establish an electrical connection between the battery 1 and the current network 300. Current from the battery 1 can flow into the current network 300 through the AC interface 3, and current from the current network 300 can also flow into the battery 1 through the AC interface 3.

[0087] The on-board charger 2 is connected between the battery 1 and the AC interface 3. The power of the on-board charger 2 is P, where 3KW≤P≤15KW. The on-board charger 2 has an AC port for connecting to the AC interface 3. The voltage of the AC port of the on-board charger 2 can be 220VAC or 380VAC, and this application does not impose any limitation on this.

[0088] When the battery pack 100 is used in electrical equipment, the AC power in the current network 300 can flow to the on-board charger 2 through the AC interface 3, and then be converted to DC power at the on-board charger 2 before flowing to the battery 1, thereby charging the battery 1. When the battery pack 100 is connected to an energy storage station, the AC power in the current network 300 can reach the on-board charger 2 through the AC interface 3, and then be converted to DC power at the on-board charger 2 before flowing to the battery 1, thereby charging the battery 1. The DC power from the battery 1 can also reach the on-board charger 2, and then be converted to AC power at the on-board charger 2 before flowing to the current network 300 through the AC interface 3, thereby supplying power to the electrical loads within the current network 300. The on-board charger 2 allows the battery pack 100 to be directly connected to the grid of the energy storage station after it is decommissioned. This solves the problem that battery packs 100 with different voltage platforms need to be connected using different models of energy storage inverters, improves the connection efficiency between battery pack 100 and energy storage power station, and reduces the connection cost between battery pack 100 and energy storage power station.

[0089] The battery pack 100 also includes a battery management system 4. The battery management system 4 is configured to monitor the temperature, remaining charge, current, and voltage of each cell in the battery 1, so as to react promptly when abnormal operating parameters of the battery 1 occur and protect the circuit safety. On the other hand, the battery management system 4 can also receive signals from the controller 200.

[0090] Specifically, when the battery management system 4 receives a discharge signal from the controller 200, the battery management system 4 controls the on-board charger 2 to enter the first working mode. In the first working mode, the current in the on-board charger 2 is only allowed to flow in the direction from the battery 1 to the AC interface 3. The current in the battery 1 can flow through the on-board charger 2 and the AC interface 3 to the current network 300, thereby supplying power to the electrical load in the current network 300.

[0091] When the battery management system 4 receives a charging signal from the controller 200, it can control the on-board charger 2 to enter a second operating mode. In this mode, the current in the on-board charger 2 is only allowed to flow along the AC interface 3 towards the battery 1. The current in the current network 300 can flow through the on-board charger 2 and the AC interface 3 towards the current network 300, thereby charging the battery 1.

[0092] The battery management system 4 can receive discharge and charging signals from the controller 200 via Bluetooth or Wi-Fi, and this application does not limit this. In one embodiment of this application, the battery pack 100 further includes a first power interface 5, which is connected to the battery management system 4. The first power interface 5 is a low-voltage interface. When the battery pack 100 is used in an electrical device, the starting battery 1 located in the electrical device can be connected to the battery management system 4 through the first power interface 5, thereby providing power for the operation of the battery management system 4. When the battery pack 100 is integrated into the energy storage system 1000, the energy storage system 1000 can supply power to the battery management system 4 through the first power interface 5, and the signal harness of the controller 200 can be electrically connected to the battery management system 4 through the first power interface 5. The discharge and charging signals of the controller 200 can be transmitted to the battery management system 4 through the first power interface 5. Compared to Bluetooth or network connections, the controller 200 and battery management system 4 use a wire harness for transmission and the first power interface 5 for reception, resulting in faster signal transmission and better signal stability.

[0093] The battery pack 100 also includes a second power interface 6, which is connected to the battery 1. The second power interface 6 is a high-voltage interface; when the battery pack 100 is used in electrical equipment, the battery 1 can output high-voltage voltage through the second power interface 6. The second power interface 6 can be directly connected to the high-voltage electrical components of the electrical equipment, thereby supplying power to these components. Alternatively, the second power interface 6 can be connected to the low-voltage electrical components of the electrical equipment via a DC-DC converter (DCDC), thereby supplying power to these low-voltage components.

[0094] It should be noted that when the electrical equipment is a vehicle, the aforementioned high-voltage electrical components can be motors, air conditioning compressors, or vehicle PTC heaters; this application does not impose any restrictions on this. The aforementioned low-voltage electrical components can be vehicle dashboard lights, vehicle displays, or door switches; this application does not impose any restrictions on this.

[0095] The battery pack 100 also includes a first switch module 7 and a second switch module 8. The first switch module 7 and the second switch module 8 can be relays, contactors, or electronic switches; this application does not impose any limitations on these. The first switch module 7 and the second switch module 8 are connected between the battery 1, the second power interface 6, and the on-board charger 2 to form a current loop among them. The first switch module 7 and the second switch module 8 can control the direction of current flow between the battery 1, the second power interface 6, and the on-board charger 2 by controlling their own on / off states. This allows the battery pack 100 to cut off the current to either the second power interface 6 or the on-board charger 2 when only one is operating, preventing the other from being unnecessarily energized and protecting the circuit safety.

[0096] There are multiple ways to connect the first switch module 7 and the second switch module 8 between the battery 1, the second power interface 6, and the on-board charger 2. Please refer to Figure 3. In one embodiment of this application, the first end of the first switch module 7 is connected to the battery 1, the second end of the first switch module 7 is connected to the second power interface 6, the first end of the second switch module 8 is connected to the second power interface 6, and the second end of the second switch module 8 is connected to the on-board charger 2.

[0097] When both the on-board charger 2 and the second power interface 6 are connected to a load, the first switch module 7 and the second switch module 8 are closed. The current from the battery 1 can flow to the on-board charger 2 through the first switch module 7, thereby supplying power to the on-board charger 2. The current from the battery 1 can also flow to the second power interface 6 through the first switch module 7 and the second switch module 8, thereby supplying power to the second power interface 6.

[0098] When the second power interface 6 is unloaded, the battery management system 4 only needs to disconnect the second switch to stop the power supply to the second power interface 6. In this way, the possibility of current breakdown caused by excessive voltage at the first and second input terminals of the second power interface 6 when it is unloaded is reduced, thereby improving the safety of the battery pack 100.

[0099] Please refer to Figure 4. In another possible embodiment of this application, the first end of the first switch module 7 is connected to the battery 1, the second end of the first switch module 7 is connected to the first end of the second switch module 8 and the second power interface 6; the second end of the second switch module 8 is connected to the second DC converter.

[0100] When both the on-board charger 2 and the second power interface 6 are connected to a load, the first switch module 7 and the second switch module 8 are closed. Current from the battery 1 can flow through the first switch module 7 to the second power interface 6 to supply power to the second power interface 6. Current from the battery 1 can also flow through the first switch module 7 and the second switch module 8 to the on-board charger 2 to supply power to the on-board charger 2.

[0101] When the on-board charger 2 is unloaded, the battery management system 4 only needs to disconnect the second switch to stop supplying power to the on-board charger 2, thereby reducing the energy consumption of the battery pack 100 at the on-board charger 2 and extending the service life of the battery pack 100.

[0102] Please refer to Figure 5. In another possible embodiment of this application, the first end of the first switch module 7 is connected to the battery 1, and the second end of the first switch module 7 is connected to the second power interface 6; the first end of the second switch module 8 is connected to the battery 1, and the second end of the second switch module 8 is connected to the second DC converter.

[0103] When the on-board charger 2 and the second power interface 6 are connected to a load, the battery management system 4 can control the first switch module 7 and the second switch module 8 to close. The current from the battery 1 can flow through the first switch module 7 to the second power interface 6, thereby supplying power to the second power interface 6. The current from the battery 1 can also flow through the second switch module 8 to the on-board charger 2, thereby supplying power to the on-board charger 2.

[0104] When the second power interface 6 is unloaded, the battery management system 4 disconnects the first switch module 7, thereby stopping the power supply to the second power interface 6. This reduces the possibility of current breakdown caused by excessive voltage at the first and second input terminals of the second power interface 6 when it is unloaded, and improves the safety of the battery pack 100.

[0105] When the on-board charger 2 is unloaded, the battery management system 4 disconnects the second switch module 8, thereby stopping the power supply to the on-board charger 2, reducing the energy consumption of the battery pack 100 at the on-board charger 2, and extending the service life of the battery pack 100.

[0106] Compared to other implementation methods, this implementation method allows for independent control of the on-board charger 2 and the second power interface 6, resulting in more adjustable modes between the on-board charger 2 and the second power interface 6. Furthermore, the parallel connection of the first switch module 7 and the second switch module 8 eliminates the need for the second switch module 8 to handle high-voltage current. Therefore, a lower-power and cheaper switch module can be selected as the second switch module 8 connected between the battery 1 and the on-board charger 2, thereby reducing the manufacturing cost of the battery pack 100.

[0107] Referring to Figure 2, the battery pack 100 also includes a third switch module 9, which is connected between the on-board charger 2 and the AC interface 3. The third switch module 9 can be a relay, a contactor, or an electronic switch; this application does not limit its application to these. The third switch module 9 can control the current flow between the on-board charger 2 and the AC interface 3 by controlling its own on / off state. This allows the battery pack 100 to promptly disconnect the current connection between the current network 300 and the on-board charger 2, preventing damage to the on-board charger 2 due to prolonged power supply, extending the lifespan of the on-board charger 2, and protecting its operational safety.

[0108] Please refer to Figure 6. This application also proposes a grid connection management method, which is applied to the above-mentioned battery pack. The grid connection management method includes:

[0109] S101. When the battery management system receives a discharge signal, the battery management system controls the battery current to flow to the current network through the on-board charger and AC interface to supply power to the current network.

[0110] There are several ways for a battery management system (BMS) to receive discharge signals. The BMS can receive discharge signals from the controller of the energy storage system via Bluetooth connection, or via a network connection. In one embodiment of this application, the battery pack further includes a first power interface connected to the BMS. The BMS receives discharge signals through the first power interface. In this embodiment, the controller is connected to the first power interface of the battery pack via a signal transmission line, and then to the BMS via the first power interface. The controller's discharge signal can be transmitted to the first power interface via the signal transmission line, and then from the first power interface to the BMS. Compared to other methods, the method of using a wiring harness for transmission between the controller and the BMS, with reception via the first power interface, results in faster signal transmission speed, better signal stability, and stronger anti-interference capability.

[0111] There are various ways for the battery management system to control the flow of battery current to the current network via the on-board charger and AC interface. In one embodiment of this application, the battery pack further includes a first switch module and a third switch module. The third switch module is connected between the on-board charger and the AC interface, and the first switch module is connected between the battery and the on-board charger.

[0112] Please refer to Figure 7. The battery management system controls the flow of battery current through the on-board charger and AC interface to the current network, including the following steps:

[0113] S1011, The battery management system controls the closing of the first switch module and the third switch module.

[0114] S1012 The battery management system controls the on-board charger to enter the first working mode. In the first working mode, the current in the on-board charger is only allowed to flow in the direction from the battery to the AC interface.

[0115] In this embodiment, the on-board charger is configured as a dual-isolated AC-DC converter. The on-board charger has a first operating mode, in which current is only allowed to flow from the battery to the AC interface. When the battery management system receives a discharge signal, it controls the first and third switching modules to close, thereby enabling current interconnection between the battery, the on-board charger, and the AC interface. Battery current can then flow through the on-board charger towards the current network, thus supplying power to the electrical loads within the current network. During current transmission, the dual-isolated on-board charger effectively isolates the input circuit of the current network from the output circuit of the battery, preventing electrical faults such as backflow or short circuits, thereby significantly improving operational safety.

[0116] Understandably, in other possible embodiments of this application, the on-board charger may also be configured as two single-isolation modes, i.e., of the two on-board chargers, the current of on-board charger a is only allowed to flow in the direction from the battery to the AC interface, and the current of on-board charger b is only allowed to flow in the direction from the AC interface to the battery. On-board charger a is connected to the battery through a fourth switch module, and on-board charger b is connected to the battery through a fifth switch module. When the battery management system receives a discharge signal, the battery management system only needs to control the fourth switch module to close and the fifth switch module to open, so that the battery current can flow through the on-board charger and the AC interface to the current network to power the current network.

[0117] To protect the circuit's safety, in one embodiment of this application, the battery pack stops supplying power to the current network when at least one of the following conditions is met: a discharge stop signal is received. This discharge stop signal can be issued by the controller (for example, during the charging process of the battery pack by the current network, if the power generation of the generator in the current network exceeds the power consumption of the load, the controller will send a discharge stop signal to the battery management system and switch the current network to supply power to the battery pack), or it can be issued manually. Upon receiving the discharge stop signal, the battery management system controls the battery pack to stop discharging.

[0118] When the battery pack reaches the discharge cutoff condition, the battery has a preset minimum charge level. When the battery charge level is less than the minimum charge level, the battery management system determines that the battery pack has reached the discharge cutoff condition, stops discharging, and protects the battery safety.

[0119] When the battery pack reaches the end of its lifespan, the battery circuit system will control the battery pack to stop discharging. There are several ways to determine the end of battery lifespan. For example, batteries typically store a preset number of charge-discharge cycles. When the battery reaches this preset number of cycles, the battery management system determines that the battery has reached the end of its lifespan and stops discharging into the current network. The battery management system can also determine battery lifespan based on battery capacitance or equalization voltage. When the battery capacitance is less than a preset capacitance or the equalization voltage is less than a preset equalization voltage, the battery management system determines that the battery has reached the end of its lifespan and stops discharging into the current network to protect the circuit.

[0120] Circuit faults in the battery pack can be categorized into several types. These include connection failures, such as loosening, breakage, or corrosion of wiring harnesses within the battery pack. When the battery management system (BMS) detects a connection fault, it will cut off power supply to the current network to protect the circuit. Insulation faults, such as damage to the battery pack's insulation, can also cause leakage and short circuits. Similarly, when the BMS detects an insulation fault, it will cut off power supply to the current network to protect the circuit. In addition to these, faults in the battery piping system and sensors within the battery pack also constitute circuit faults. When such faults occur, the BMS will disconnect the battery pack from the current network to protect both the battery pack and the current network.

[0121] S102. When the battery management system receives a charging signal, the battery management system controls the current of the battery to flow to the battery through the AC interface and the on-board charger to charge the battery.

[0122] There are several ways for a battery management system (BMS) to receive charging signals. The BMS can receive charging signals from the controller of the energy storage system via Bluetooth connection, or via a network connection. In one embodiment of this application, the battery pack further includes a first power interface connected to the BMS. The BMS receives charging signals through the first power interface. In this embodiment, the controller is connected to the first power interface of the battery pack via a signal transmission line, and then to the BMS via the first power interface. The controller's charging signal can be transmitted to the first power interface via the signal transmission line, and then from the first power interface to the BMS. Compared to other methods, the method of using a wiring harness for transmission between the controller and the BMS, with the first power interface for reception, results in faster signal transmission speed, better signal stability, and stronger anti-interference capability.

[0123] There are various ways for the battery management system to control the flow of current from the battery to the battery via the AC interface and the on-board charger. In one embodiment of this application, the battery pack further includes a first switch module and a third switch module. The third switch module is connected between the on-board charger and the AC interface, and the first switch module is connected between the battery and the on-board charger.

[0124] Please refer to Figure 8. The battery management system controls the flow of current from the battery to the battery via the AC interface and the on-board charger, including the following steps:

[0125] S1021, The battery management system controls the closing of the first switch module and the third switch module.

[0126] S1022 The battery management system controls the on-board charger to enter the second working mode. In the second working mode, the current in the on-board charger is only allowed to flow along the AC interface to the battery.

[0127] In this embodiment, the on-board charger is configured as a dual-isolated AC-DC converter. The on-board charger has a second operating mode, in which current is only allowed to flow from the AC interface to the battery. When the battery management system receives a charging signal, it controls the first and third switching modules to close, thereby enabling current interconnection between the battery, the on-board charger, and the AC interface. Battery current can then flow through the current network towards the on-board charger, thus supplying power to the electrical loads within the current network. During current transmission, the dual-isolated on-board charger effectively isolates the input circuit of the current network from the output circuit of the battery, preventing electrical faults such as backflow or short circuits, thereby significantly improving operational safety.

[0128] Understandably, in other possible embodiments of this application, the on-board charger may also be configured as two single-isolation modes, i.e., of the two on-board chargers, the current of on-board charger a is only allowed to flow in the direction from the battery to the AC interface, and the current of on-board charger b is only allowed to flow in the direction from the AC interface to the battery. On-board charger a is connected to the battery through a fourth switching module, and on-board charger b is connected to the battery through a fifth switching module. When the battery management system receives a discharge signal, the battery management system only needs to control the fourth switching module to open and the fifth switching module to open, so that the current of the battery can flow to the battery through the AC interface and the on-board charger to charge the battery.

[0129] To protect the circuit's safety, in one embodiment of this application, the battery pack stops charging when at least one of the following conditions is met:

[0130] Upon receiving a charging stop signal, which can be issued by the controller (e.g., during the charging of the battery pack by the current network, if the power generation of the generator in the current network is less than the power consumption of the load, the controller will send a charging stop signal to the battery management system and switch the battery pack to be powered by the current network), or manually, the battery management system will control the battery pack to stop charging.

[0131] When the battery pack reaches the charging cutoff condition, the battery management system determines that the charging has stopped once the battery has been charged to a preset level. It then disconnects the battery from the current network, thus stopping the charging of the battery pack. This preset level is typically the battery's full charge level.

[0132] When the battery pack reaches the end of its lifespan, the battery circuit system will control the battery pack to stop discharging. There are several ways to determine the end of battery lifespan. For example, batteries typically store a preset number of charge-discharge cycles. When the battery reaches this preset number of cycles, the battery management system determines that the battery has reached the end of its lifespan and stops discharging into the current network. The battery management system can also determine battery lifespan based on battery capacitance or equalization voltage. When the battery capacitance is less than a preset capacitance or the equalization voltage is less than a preset equalization voltage, the battery management system determines that the battery has reached the end of its lifespan and stops discharging into the current network to protect the circuit.

[0133] Circuit faults in the battery pack can be categorized into several types. These include connection failures, such as loosening, breakage, or corrosion of wiring harnesses within the battery pack. When the battery management system (BMS) detects a connection fault, it will stop charging the battery to protect the circuit. Insulation faults, such as damage to the battery pack's insulation layer, can lead to leakage and short circuits. When the BMS detects an insulation fault, it will stop charging to protect the circuit. Furthermore, faults in the battery piping system and sensors within the battery pack also constitute circuit faults. When these occur, the BMS will disconnect the battery pack from the current network to protect both the battery pack and the current network.

[0134] Please refer to Figure 9. In one possible implementation of this application, the grid connection management method includes:

[0135] S201. When the battery management system receives a discharge signal, the battery management system controls the battery current to flow to the current network through the on-board charger and AC interface to supply power to the current network.

[0136] S202. When the battery management system receives a charging signal, the battery management system controls the current of the battery to flow to the battery through the AC interface and the on-board charger to charge the battery.

[0137] S203. When the battery pack meets the off-grid conditions, disconnect the current connection between the battery and the on-board charger, as well as between the on-board charger and the AC interface.

[0138] Off-network conditions include at least one of the following:

[0139] Upon receiving an off-grid signal, which can be sent by the controller or manually, the off-grid signal is received.

[0140] When the battery pack reaches the charging cutoff condition or the discharging cutoff condition, and the battery pack's charge reaches the preset charge level, the battery management system determines that the battery pack is fully charged. It then controls the battery pack to disconnect the current connection between the battery and the on-board charger, as well as between the on-board charger and the AC interface, to prevent the current network from overcharging the battery and protect the battery safety.

[0141] When the battery charge falls below the minimum charge level, the battery management system determines that the battery pack has reached the discharge cutoff condition, thus stopping the discharge and protecting the battery. The battery pack's lifespan ends at this point.

[0142] Circuit faults in the battery pack can be categorized into several types. These include connection failures, such as loosening, breakage, or corrosion of wiring harnesses within the battery pack. When the battery management system (BMS) detects a connection fault, it will stop discharging and charging the battery to protect the circuit. Insulation faults, such as damage to the battery pack's insulation layer, can lead to leakage and short circuits. When the BMS detects an insulation fault, it will stop discharging and charging the battery to protect the circuit. In addition to these, faults in the battery piping system and sensors within the battery pack also constitute circuit faults. When such faults occur, the BMS will disconnect the battery pack from the current network to protect both the battery pack and the current network.

[0143] In one embodiment of this application, the battery pack further includes a first switch module and a third switch module. The battery management system disconnects the current connection between the battery and the on-board charger, as well as between the on-board charger and the AC interface, including the following steps:

[0144] S2031, The battery management system controls the first switch module and the third switch module to disconnect.

[0145] S2032, The battery management system controls the on-board charger to enter the third working mode. In the third working mode, the current is not allowed to flow in any direction.

[0146] In this embodiment, when the battery management system determines that the battery pack needs to be disconnected from the grid, it will disconnect the first and third switching modules, thereby disconnecting the battery, the on-board charger, and the AC interface. Simultaneously, the battery management system will also control the on-board charger to enter a third operating mode. In this mode, current is not allowed to flow in any direction, thus providing dual protection against disconnection from the battery and the current network, ensuring circuit safety.

[0147] In the description of the embodiments of this application, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0148] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments and equivalent variations made in accordance with the claims of this application are still within the scope of this application.

Claims

1. A battery pack (100), wherein, The battery pack (100) includes a battery (1), an on-board charger (2), an AC interface (3), and a battery management system (4), wherein the battery (1) is used to provide direct current; The battery (1) is connected to the AC interface (3) via the on-board charger (2); the on-board charger (2) is used to convert the DC current of the battery (1) into AC current, or to convert the AC current transmitted by the AC interface (3) into DC current. The battery management system (4) is connected to the battery (1) and the on-board charger (2). When a discharge signal is received, the battery management system (4) controls the current of the battery (1) to flow to the current network (300) via the on-board charger (2) and the AC interface (3); when a charging signal is received, the battery (1) controls the current of the battery (1) to flow to the battery (1) via the AC interface (3) and the on-board charger (2).

2. The battery pack (100) as claimed in claim 1, wherein, The battery pack (100) further includes a first power interface (5), which is connected to the battery management system (4). The first power interface (5) is used to receive the discharge signal and the charging signal.

3. The battery pack (100) as described in any one of claims 1 or 2, wherein, The battery pack (100) also includes a first switch module (7), a second switch module (8), and a second power interface (6); The first switch module (7) and the second switch module (8) are connected between the battery (1), the second power interface (6) and the on-board charger (2) to form a current loop between the battery (1), the second power interface (6) and the on-board charger (2).

4. The battery pack (100) as claimed in claim 3, wherein, The first end of the first switch module (7) is connected to the battery (1), and the second end of the first switch module (7) is connected to the second power interface (6) and the first end of the second switch module (8). The second end of the second switch module (8) is connected to the on-board charger (2).

5. The battery pack (100) as claimed in claim 3, wherein, The first end of the first switch module (7) is connected to the battery (1), and the second end of the first switch module (7) is connected to the second power interface (6); The first end of the second switch module (8) is connected to the battery (1), and the second end of the second switch module (8) is connected to the on-board charger (2).

6. The battery pack (100) as claimed in claim 3, wherein, The first end of the first switch module (7) is connected to the battery (1), and the second end of the first switch module (7) is connected to the on-board charger (2) and the first end of the second switch module (8); The second end of the second switch module (8) is connected to the first power interface (5).

7. The battery pack (100) as described in any one of claims 1-6, wherein, The battery pack (100) also includes a third switch module (9), which is connected between the on-board charger (2) and the AC interface (3).

8. A grid connection management method, wherein, The method is applied to a battery pack (100), which includes a battery (1), an on-board charger (2), an AC interface (3), and a battery management system (4). The battery (1) is connected to the AC interface (3) via the on-board charger (2), and the battery management system (4) is connected to the battery (1) and the on-board charger (2). The grid connection management method includes: S101. When the battery management system (4) receives a discharge signal, the battery management system (4) controls the current of the battery (1) to flow to the current network (300) through the on-board charger (2) and AC interface (3) to supply power to the current network (300). S102. When the battery management system (4) receives a charging signal, the battery management system (4) controls the current of the battery (1) to flow to the battery (1) through the AC interface (3) and the on-board charger (2) to charge the battery (1).

9. The grid connection management method as described in claim 8, wherein, The battery pack (100) also includes a first power interface (5), which is connected to the battery management system (4); The battery management system (4) receives the discharge signal and the charging signal through the first power interface (5).

10. The grid connection management method as described in claim 8, wherein, The battery pack (100) also includes a first switch module (7) and a third switch module (9), the third switch module (9) being connected between the on-board charger (2) and the AC interface (3), and the first switch module (7) being connected between the battery (1) and the on-board charger (2); The battery management system controls the flow of current from the battery (1) to the current network (300) via the on-board charger (2) and AC interface (3) by the following steps: The battery management system (4) controls the first switch module (7) and the third switch module (9) to close; The battery management system controls (4) the on-board charger (2) to enter a first working mode. In the first working mode, the current in the on-board charger (2) is only allowed to flow in the direction from the battery (1) to the AC interface (3).

11. The grid connection management method as described in claim 8, wherein, The battery pack (100) also includes a first switch module (7) and a third switch module (9), the third switch module (9) being connected between the on-board charger (2) and the AC interface (3), and the first switch module (7) being connected between the battery (1) and the on-board charger (2); The battery management system (4) controls the flow of current from the battery (1) to the battery pack (100) via the AC interface (3) and the on-board charger (2) by the following steps: The battery management system (4) controls the first switch module (7) and the third switch module (9) to close; The battery management system (4) controls the on-board charger (2) to enter a second working mode. In the second working mode, the current in the on-board charger (2) is only allowed to flow along the AC interface (3) to the battery (1).

12. The grid connection management method as described in any one of claims 8-11, wherein, The battery pack (100) stops supplying power to the current network (300) when at least one of the following conditions is met: Received a discharge stop signal; or The battery pack (100) has reached the discharge cutoff condition; or The battery life of the battery pack (100) has ended; or The battery pack (100) has a circuit fault.

13. The grid connection management method according to any one of claims 8-11, wherein, The battery pack (100) stops charging when at least one of the following conditions is met: Received a charging stop signal; or The battery pack (100) has reached the charging cutoff condition; or The battery life of the battery pack (100) has ended; or The battery pack (100) has a circuit fault.

14. The grid connection management method as described in any one of claims 8-13, wherein, The grid connection management method also includes: When the battery pack (100) meets the off-grid conditions, disconnect the current connection between the battery (1) and the on-board charger (2), as well as between the on-board charger (2) and the AC interface (3).

15. The grid connection management method as described in claim 14, wherein, The offline conditions include at least one of the following: Received off-grid signal; or The battery pack (100) has reached the charging cutoff condition or the battery pack (100) has reached the discharging cutoff condition; or The battery life of the battery pack (100) has ended; The battery pack (100) has a circuit fault.

16. An electrical energy device, wherein, It includes an electrical device and a battery pack (100) electrically connected to the electrical device, wherein the battery pack (100) is the battery pack (100) as described in any one of claims 1 to 7.

17. An energy storage system (1000), wherein, include: Current network (300); At least one battery pack (100) as described in any one of claims 1 to 9, the battery pack (100) being connected to the current network (300); A controller (200) is electrically connected to the battery pack (100).

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