Energy storage system and black start device

Abstract

The application provides an energy storage system and a black start device. The energy storage system comprises a battery cluster and a black start bus. The battery cluster comprises a plurality of battery packs connected in series. A target battery pack in the plurality of battery packs carries a black start control. The black start control is used to turn on an electrical connection between the target energy storage battery and a target auxiliary power supply when triggered. The target auxiliary power supply is used to supply power to a target controller and the black start bus based on the electrical energy provided by the target energy storage battery, so as to trigger the black start bus to supply power to the auxiliary power supplies of other battery packs. The auxiliary power supplies in the other battery packs are used to turn on the electrical connection with the energy storage batteries based on the electrical energy provided by the black start bus, and supply power to the controllers based on the electrical energy provided by the energy storage batteries. By using the application, the problems of poor starting experience, high cost and low reliability caused by the fact that all battery packs need to be installed with black start controls can be avoided. In addition, the power supply power of the UPS is reduced when the black start is performed through the UPS, and the cost of the black start is significantly reduced.

Description

Technical Field

[0001] This application relates to the field of electronic power, and more particularly to an energy storage system and a black start device. Background Technology

[0002] Black start refers to the recovery of a system after a failure, without relying on other networks. It involves starting self-starting units within the system, which then drive units without self-starting capabilities, gradually expanding the recovery scope until the entire system is restored. Black start is widely used in various energy storage systems. When an energy storage system disconnects from the grid due to a fault, it is in off-grid mode. Black start triggers the battery modules in the energy storage system to restore the connection between the off-grid system and the grid-connected equipment. Generally, black start is achieved through an uninterrupted power supply (UPS) or by utilizing the battery clusters' own power. However, for large-capacity energy storage systems (such as those containing hundreds of battery packs), UPS-powered black start solutions require significant power output from the UPS, resulting in high costs. Furthermore, when the battery packs in the energy storage system are not continuously connected to the bus, the cluster-level battery bus cannot supply power before startup, thus preventing the use of the battery clusters' own power for black start. Summary of the Invention

[0003] This application provides an energy storage system and a black start device, which can solve the problem of achieving black start when the battery pack has a built-in battery optimizer. It avoids the problems of poor start-up experience, high cost and low reliability caused by the need to install black start control in all battery packs in the battery cluster. It also reduces the power supply of the UPS when performing black start through the UPS, thus significantly reducing the cost of black start.

[0004] In a first aspect, this application provides an energy storage system comprising a battery cluster and a black-start bus. The battery cluster is coupled to an AC power grid and includes multiple battery packs connected in series. Each battery pack includes an energy storage battery, a controller, and an auxiliary power supply connected in parallel with the energy storage battery. The auxiliary power supply is coupled to the black-start bus. The multiple battery packs include a target battery pack associated with a black-start control. The black-start control is disposed between a target energy storage battery and a target auxiliary power supply within the target battery pack. When triggered, the black-start control establishes an electrical connection between the target energy storage battery and the target auxiliary power supply. The target auxiliary power supply supplies power to the target controller and the black-start bus within the target battery pack based on the electrical energy provided by the target energy storage battery, thereby triggering the black-start bus to supply power to the auxiliary power supplies of the other battery packs besides the target battery pack. The auxiliary power supply of each battery pack in the other battery packs mentioned above is used to make electrical connections with each energy storage battery of each battery pack based on the electrical energy provided by the black start bus, and to supply power to the controller of each battery pack based on the electrical energy provided by each energy storage battery.

[0005] In this application, a target battery pack in multiple battery packs establishes an electrical connection between its target energy storage battery and the target auxiliary power supply via a black-start control. This allows the target auxiliary power supply to power the target controller and the black-start bus in the target battery pack based on the electrical energy provided by the target energy storage battery. This triggers the black-start bus to supply power to the auxiliary power supplies of the other battery packs in the multiple battery packs, excluding the target battery pack. The auxiliary power supplies of each of the other battery packs establish electrical connections with their respective energy storage batteries based on the electrical energy provided by the black-start bus, and supply power to the controllers of their respective battery packs based on the electrical energy provided by the energy storage batteries. By triggering the black-start control in a single target battery pack, the energy storage system causes the target battery pack to draw power from its energy storage battery and supply power to the black-start bus, which then supplies power to the auxiliary power supplies of other battery packs (establishing electrical connections between the auxiliary power supplies and energy storage batteries of other battery packs). This avoids the problems of poor startup experience, high cost, and low reliability caused by requiring black-start controls to be installed in all battery packs within a battery cluster. Furthermore, the UPS power required for black start is very small (the UPS only supplies power to the process of connecting the auxiliary power supply and the energy storage battery), which reduces the UPS capacity when equipped with a UPS, thus significantly reducing the cost of black start.

[0006] In conjunction with the first aspect, in a first possible implementation, the battery pack further includes an isolation power supply circuit, through which the auxiliary power supply is connected in parallel to the black start bus. The isolation power supply circuit is used to transmit electrical energy from the black start bus to the auxiliary power supply in an electrically isolated manner. The electrical isolation between the black start bus and the battery pack effectively avoids the problem of voltage mismatch on the black start bus caused by battery pack expansion.

[0007] In conjunction with the first possible implementation of the first aspect, in the second possible implementation, the aforementioned isolated power supply circuit includes a first isolation optocoupler. The input terminal of the first isolation optocoupler is coupled to the black start bus, and the energy storage battery is connected to the start port of the auxiliary power supply through the output terminal of the first isolation optocoupler. The first isolation optocoupler is used to transfer electrical energy from its input terminal to its output terminal, thereby establishing an electrical connection between the energy storage battery and the start port of the auxiliary power supply. Here, the light-emitting diode in the first isolation optocoupler converts the input electrical energy into a light signal, which is then transmitted to a phototransistor and converted into electrical energy output. This allows for electrical energy transfer between the black start bus and the battery pack under electrically isolated conditions, preventing interference caused by an electrical connection between the black start bus and the battery pack.

[0008] In conjunction with the second possible implementation of the first aspect, in the third possible implementation, the output terminal of the first isolation optocoupler in the target battery pack is connected in parallel with the black start control between the start port of the target energy storage battery and the target auxiliary power supply in the target battery pack. The target isolation power supply circuit in the target battery pack also includes an isolation winding, and the power supply port of the target auxiliary power supply is connected to the black start bus through the isolation winding. The target auxiliary power supply is used to draw power from the target energy storage battery and supply power to the black start bus through the isolation winding. By triggering the black start control in a single target battery pack, the energy storage system causes the target battery pack to draw power from the energy storage battery in that battery pack and supply power to the black start bus, and then supply power to the auxiliary power supply of other battery packs through the black start bus (to connect the auxiliary power supply of other battery packs and the energy storage battery), thus avoiding the problems of poor start-up experience, high cost, and low reliability caused by installing black start controls in all battery packs within the battery cluster.

[0009] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation, the target isolated power supply circuit further includes a voltage adjustment unit. The primary winding of the isolation winding is connected to the target auxiliary power supply through the voltage adjustment unit. The target controller in the target battery pack controls the voltage adjustment unit to perform voltage transformation on the output voltage of the target auxiliary power supply, so as to output the target voltage to the black start bus through the isolation winding. Here, the voltage adjustment unit transforms the output voltage of the auxiliary power supply port, causing the isolation winding to further transform the voltage output by the voltage adjustment unit and perform corresponding on / off control. The secondary winding of the isolation winding outputs the target voltage to the black start bus. The black start bus can transmit a black start signal to other battery packs in the battery cluster based on the auxiliary power supply through the isolated power supply of the isolation winding, so that the auxiliary power supplies in other battery packs besides the target battery pack are started.

[0010] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation, the aforementioned target isolated power supply circuit further includes a voltage adjustment unit and a second isolation optocoupler. The secondary winding of the isolation winding is connected to the black start bus via the voltage adjustment unit. The input terminal of the second isolation optocoupler is connected to the target controller in the target battery pack, and the output terminal of the second isolation optocoupler is connected to the voltage adjustment unit. The target controller in the target battery pack sends control commands to the voltage adjustment unit via the second isolation optocoupler. The control commands control the voltage adjustment unit to perform voltage transformation on the secondary winding voltage of the isolation winding, so as to output a target voltage to the black start bus via the isolation winding. The light-emitting diode in the second isolation optocoupler converts the input electrical energy into an optical signal, transmits it to the phototube, and converts it into electrical energy output. This allows for power transmission between the black start bus and the battery pack without a direct electrical connection, preventing interference caused by an electrical connection between the black start bus and the battery pack, resulting in good power transmission performance.

[0011] In a sixth possible implementation, combining any one of the first to fifth possible embodiments of the first aspect, the energy storage system further includes an uninterruptible power supply (UPS). The UPS is coupled to the black-start bus and supplies power to the black-start bus, triggering the black-start bus to supply power to the auxiliary power supplies in the multiple battery packs. Here, the black-start method, where the UPS supplies power to the black-start bus, eliminates the need to trigger the black-start control (e.g., pressing a button). The UPS only needs to supply power to establish the electrical connection between the auxiliary power supply and the energy storage battery (equivalent to supplying power to the diodes of the first isolation optocouplers in each battery pack). Its supply current is only a few milliamps. Therefore, even if the energy storage system has hundreds of battery packs, the UPS power is only tens or hundreds of watts, far lower than the scheme where the UPS directly supplies power to the individual boards in each battery pack. This reduces the UPS power capacity and significantly lowers the cost of black-start operation.

[0012] In a seventh possible implementation, combining any one of the first to sixth possible embodiments of the first aspect, each of the aforementioned battery packs further includes a first switching transistor and a second switching transistor. The first switching transistor is connected in series with the energy storage battery of each battery pack, and the second switching transistor is connected in parallel with the energy storage battery of each battery pack. The controller of each battery pack is used to control the first switching transistor of each battery pack to turn on and the second switching transistor to turn off, so as to connect the energy storage battery in each battery pack in series to the battery cluster bus. Here, the energy storage system uses the power supply of the black-start bus to achieve black start, which solves the problem that the battery cluster bus cannot start from the cluster level when the battery pack has a built-in battery optimizer (which may include the first switching transistor and the second switching transistor). This method has strong applicability.

[0013] Secondly, this application provides a black-start device for an energy storage system. The energy storage system includes battery clusters and a black-start bus. The battery clusters include multiple battery packs connected in series. Each battery pack includes an energy storage battery, a controller, and an auxiliary power supply connected in parallel with the energy storage battery. The auxiliary power supply is coupled to the black-start bus. The black-start device includes a black-start control. When triggered, the black-start control establishes an electrical connection between a target energy storage battery in a target battery pack and a target auxiliary power supply. The target auxiliary power supply powers the target controller in the target battery pack and the black-start bus based on the electrical energy provided by the target energy storage battery, thereby triggering the black-start bus to supply power to the auxiliary power supplies of the other battery packs besides the target battery pack. The black-start device uses the auxiliary power supplies of each of the other battery packs to establish electrical connections with the energy storage batteries in each of the battery packs based on the electrical energy provided by the black-start bus, and powers the controllers of each battery pack based on the electrical energy provided by the energy storage batteries.

[0014] In this application, a target battery pack in multiple battery packs establishes an electrical connection between its target energy storage battery and the target auxiliary power supply via a black-start control. This allows the target auxiliary power supply to power the target controller and the black-start bus in the target battery pack based on the electrical energy provided by the target energy storage battery. This triggers the black-start bus to supply power to the auxiliary power supplies of the other battery packs in the multiple battery packs, excluding the target battery pack. The auxiliary power supplies of each of the other battery packs establish electrical connections with their respective energy storage batteries based on the electrical energy provided by the black-start bus, and supply power to the controllers of their respective battery packs based on the electrical energy provided by the energy storage batteries. By triggering the black-start control in a single target battery pack, the energy storage system causes the target battery pack to draw power from its energy storage battery and supply power to the black-start bus, which then supplies power to the auxiliary power supplies of other battery packs (establishing electrical connections between the auxiliary power supplies and energy storage batteries of other battery packs). This avoids the problems of poor startup experience, high cost, and low reliability caused by requiring black-start controls to be installed in all battery packs within a battery cluster. Furthermore, the UPS power required for black start is very small (the UPS only supplies power to the process of connecting the auxiliary power supply and the energy storage battery), which reduces the UPS capacity when equipped with a UPS, thus significantly reducing the cost of black start.

[0015] In conjunction with the second aspect, in a first possible implementation, the aforementioned black-start device further includes an isolated power supply circuit. The auxiliary power supply is connected in parallel to the black-start bus via the isolated power supply circuit. The isolated power supply circuit includes a first isolation optocoupler. The input terminal of the first isolation optocoupler is coupled to the black-start bus. The energy storage battery is connected to the start-up port of the auxiliary power supply via the output terminal of the first isolation optocoupler. The first isolation optocoupler is used to transfer electrical energy from its input terminal to its output terminal, thereby establishing an electrical connection between the energy storage battery and the start-up port of the auxiliary power supply. Here, the light-emitting diode in the first isolation optocoupler converts the input electrical energy into a light signal, which is then transmitted to a phototransistor and converted into electrical energy output. This allows for electrical energy transfer between the black-start bus and the battery pack under electrically isolated conditions, preventing interference caused by an electrical connection between the black-start bus and the battery pack. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the application scenario of the energy storage system provided in this application;

[0017] Figure 2 This is a structural schematic diagram of the energy storage system provided in this application;

[0018] Figure 3 This is a structural schematic diagram of the battery pack provided in this application;

[0019] Figure 4 This is another structural schematic diagram of the battery pack provided in this application;

[0020] Figure 5 This is another structural schematic diagram of the energy storage system provided in this application. Detailed Implementation

[0021] See Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of the energy storage system provided in this application. The energy storage system provided in this application may include battery clusters and a black-start bus. The battery clusters may include multiple battery packs connected in series (e.g., battery pack 1, battery pack 2, ..., battery pack n, etc.). These multiple battery packs are connected to the battery cluster bus, and the battery clusters are coupled to the DC terminal of a DC / AC converter via a cluster-level DC-DC converter. The AC terminal of the DC / AC converter is coupled to the AC power grid. The cluster-level DC / DC converter can perform voltage conversion (such as boost or buck conversion) on the DC power output from the battery clusters (which may be the DC power output from each battery pack) in the energy storage system. The DC / AC converter can invert and convert the DC power output from the cluster-level DC / DC converter, and output the converted AC power to the AC power grid to supply power to batteries, communication base stations, or household appliances in the AC power grid.

[0022] In some feasible implementations, the above Figure 1 The battery clusters in the system can be directly coupled to the DC terminal of the DC / AC converter, while the AC terminal of the DC / AC converter is coupled to the AC power grid. The DC / AC converter can invert and convert the DC power output from the battery clusters in the energy storage system, and output the converted AC power to the AC power grid to power batteries, communication base stations, or household appliances in the AC power grid.

[0023] In some feasible implementations, when the aforementioned energy storage system disconnects from the grid due to a fault, it is in an off-grid mode. A black start can be used to restore the connection between the energy storage system and the grid-connected electrical equipment, and power the AC grid through the battery clusters within the energy storage system. Current black start methods involve using an uninterrupted power supply (UPS) to power the energy storage system when it disconnects from the grid due to a fault, supporting the control process for reconnecting the energy storage system to the AC grid, or utilizing the battery clusters' own power. However, for large-capacity, high-power energy storage systems (e.g., battery clusters containing hundreds or thousands of battery packs), UPS-powered black start schemes require significant power from the UPS. For example, the UPS powers each circuit board within the battery pack to connect them to the AC grid. When each circuit board needs power (including the fans within the battery pack), the power required to power a single energy storage system during the black start process becomes very large, necessitating a high UPS power requirement and resulting in high black start costs. In black-start methods utilizing the battery clusters' own power within an energy storage system, the cluster-level battery bus may be unable to supply power before startup if the battery packs are not continuously connected to the bus. For example, if the battery pack is equipped with a battery optimizer, its function is to control the switching transistors within the battery pack to balance the voltage distribution of the stored batteries when voltage imbalances occur. Each transistor requires power to turn on and off, but since the transistors within the battery pack are off by default, the cluster-level battery bus cannot supply power before startup. Therefore, even with a battery optimizer, black-start cannot be achieved using the battery clusters' own power, resulting in low applicability.

[0024] The energy storage system provided in this application includes a battery pack comprising energy storage batteries and switching transistors. The battery pack also includes a controller and an auxiliary power supply connected in parallel with the energy storage batteries. This auxiliary power supply is coupled to a black-start bus. Multiple battery packs include a target battery pack (which, for ease of description, can be referred to as a target battery pack) carrying a black-start control. The target battery pack, through its black-start control, establishes an electrical connection between the target energy storage battery and the target auxiliary power supply. This allows the target auxiliary power supply to power the black-start bus based on the electrical energy provided by the target energy storage battery, triggering the black-start bus to supply power to the auxiliary power supplies of the other battery packs besides the target battery pack. The auxiliary power supplies of each of the other battery packs can establish an electrical connection with the energy storage battery based on the electrical energy provided by the black-start bus, and power the controller based on the electrical energy provided by the energy storage battery. The controller can turn the switching transistors in each battery pack on or off to connect the energy storage batteries in each battery pack in series to the battery cluster bus. The cluster-level DC / DC converter and DC / AC converter can start based on the DC power provided by the battery packs in the battery cluster to supply AC power to the grid. The energy storage system achieves black start by utilizing the power supply of the black start bus, which solves the problem of not being able to start from the cluster level when the battery cluster bus is de-energized, even when the battery pack has a built-in battery optimizer. This makes it highly applicable and avoids the problems of poor start-up experience, high cost, and low reliability caused by installing black start controls in all battery packs within the battery cluster. In addition, when equipped with a UPS, the UPS power required for black start is very small (the UPS only needs to supply power for the process of connecting the auxiliary power supply and the energy storage battery), reducing the UPS power requirements and achieving a significant reduction in black start cost.

[0025] See Figure 2 , Figure 2 This is a structural schematic diagram of the energy storage system provided in this application. Figure 2 The energy storage system shown includes battery clusters and a black-start bus. Each battery cluster can include multiple battery packs connected in series (e.g., battery pack 1, battery pack 2, ..., battery pack n, etc.). These multiple battery packs are connected to the battery cluster bus, and the battery clusters are coupled to the DC terminal of a DC / AC converter via a cluster-level DC-DC converter. The AC terminal of the DC / AC converter is coupled to the AC power grid. The cluster-level DC / DC converter can perform voltage conversion (boost, buck, etc.) on the DC power output from the battery clusters (which can be the DC power output from each battery pack). The DC / AC converter can invert and convert the DC power output from the cluster-level DC / DC converter, and output the converted AC power to the AC power grid to supply power to the AC grid.

[0026] In some feasible implementations, the above Figure 2The battery clusters in the system can be directly coupled to the DC terminal of the DC / AC converter, while the AC terminal of the DC / AC converter is coupled to the AC power grid. The DC / AC converter can invert and convert the DC power output from the battery clusters in the energy storage system, and output the converted AC power to the AC power grid to power batteries, communication base stations, or household appliances in the AC power grid.

[0027] In some feasible implementations, Figure 2 In the energy storage system shown, each battery pack in the aforementioned battery cluster may include an energy storage battery, a first switch connected in series with the energy storage battery, and a second switch connected in parallel with the energy storage battery. Taking battery pack 1 as an example, battery pack 1 may include an energy storage battery, a first switch (which can be represented as switch S1 for convenience) and a second switch (which can be represented as switch S2 for convenience). Switch S1 is connected in series with the energy storage battery, and switch S2 is connected in parallel with the energy storage battery. Here, when switch S1 is turned on and switch S2 is turned off, the energy storage battery is connected in series to the battery cluster bus to connect to the AC power grid (it can be connected to the battery cluster bus and then coupled to the AC power grid through a cluster-level DC / DC converter and a DC / AC converter). When switch S1 is turned off and switch S2 is turned on, the energy storage battery is disconnected from the battery cluster bus. Battery pack 1 may also include a controller ( Figure 2 (Not shown) An auxiliary power supply and an isolation power supply circuit are connected in parallel with the aforementioned energy storage battery. The auxiliary power supply is coupled to the black start bus through the isolation power supply circuit. The black start bus can supply power to battery pack 1. The electrical energy provided by the black start bus is transmitted to the auxiliary power supply in battery pack 1 in an electrically isolated manner through the aforementioned isolation power supply circuit. The auxiliary power supply can be electrically connected to the energy storage battery based on the electrical energy provided by the black start bus, thereby supplying power to the controller in battery pack 1 based on the electrical energy provided by the energy storage battery. The controller can control the switching transistor S1 to turn on, so as to connect the energy storage battery in battery pack 1 in series to the battery cluster bus. It is understood that the composition of other battery packs and the process of connecting them to the battery cluster bus can refer to the above description of battery pack 1, and will not be repeated here. The cluster-level DC / DC converter and DC / AC converter can be started based on the DC power provided by the battery pack in the battery cluster (the DC power provided by the energy storage battery in the battery pack) to supply power to the AC grid. Here, the energy storage system utilizes the power supply from the black-start bus to achieve black start, solving the problem of not being able to start from the cluster level when the battery cluster bus is de-energized, even when the battery pack has a built-in battery optimizer (which may include a first switch and a second switch). This approach has strong applicability. Furthermore, if the process of connecting the auxiliary power supply to the energy storage battery is powered by a UPS, the UPS power required for black start is very small. This reduces the UPS capacity when a UPS is installed, resulting in a significant reduction in black start costs.

[0028] The following will combine Figures 2 to 5The energy storage system provided in the embodiments of this application is illustrated by example. In some feasible implementations, the electrical energy provided by the aforementioned black start bus can come from the battery packs in the battery cluster. The following example illustrates how a target battery pack (which can be one or more battery packs connected in series; this application uses the example of the target battery pack being one of multiple battery packs connected in series, and will not be repeated hereafter) supplies power to the black start bus, triggering the black start bus to supply auxiliary power to other battery packs besides the target battery pack. Please refer to [link to previous text]. Figure 3 , Figure 3 This is a structural schematic diagram of the battery pack provided in this application, as shown below. Figure 3 As shown, Figure 3 The battery pack in the above-mentioned battery cluster can be the target battery pack among multiple battery packs connected in series. This battery pack may include a first isolation optocoupler. The input terminal of the first isolation optocoupler is coupled to the black start bus, and the energy storage battery is connected to the start port of the auxiliary power supply through the output terminal of the first isolation optocoupler. When the black start bus supplies power to the auxiliary power supply in the battery pack, the first isolation optocoupler can transfer the electrical energy from its input terminal to its output terminal, thus transferring the electrical energy to the auxiliary power supply in an electrically isolated manner. This allows the auxiliary power supply to establish an electrical connection with the energy storage battery based on the electrical energy provided by the black start bus. Optionally, Figure 3 The battery pack also includes a controllable switch. The auxiliary power supply can power the controller based on the electrical energy provided by the energy storage battery. The controller can control the controllable switch to turn on, thereby establishing the electrical connection between the energy storage battery and the auxiliary power supply. This ensures that the auxiliary power supply maintains its electrical connection with the energy storage battery even when the black start bus no longer provides power. The light-emitting diode in the first isolation optocoupler converts the input electrical energy into an optical signal, which is then transmitted to the phototransistor and converted into electrical energy output. This allows for power transmission between the black start bus and the battery pack without a direct electrical connection, preventing interference caused by an electrical connection between the black start bus and the battery pack, resulting in good power supply performance.

[0029] In some feasible implementations, the above Figure 3 The target battery pack includes a switch S1 connected in series with the energy storage battery and a switch S2 connected in parallel with the energy storage battery. Switches S1 and S2 are off by default and can be turned on or off by a controller. The controller requires an external power supply to control each switch. Furthermore, the aforementioned... Figure 3The target battery pack may also include a black start control and an isolation winding. The black start control may be a button. The output terminal of the first isolation optocoupler in the target battery pack is connected in parallel with the black start control between the start port of the energy storage battery (which may be the target energy storage battery for ease of description) and the auxiliary power supply (which may be the target auxiliary power supply for ease of description). The power supply port of the target auxiliary power supply is connected to the black start bus through the isolation winding. The aforementioned black-start control, when triggered (e.g., when a button is pressed and held for a period of time), establishes the electrical connection between the target energy storage battery and the target auxiliary power supply. The target auxiliary power supply can then power the target controller in the target battery pack based on the electrical energy provided by the target energy storage battery, and supply power to the black-start bus via the aforementioned isolation winding. This triggers the black-start bus to supply power to the auxiliary power supplies of the other battery packs besides the target battery pack, enabling each battery pack's auxiliary power supply to establish an electrical connection with its respective energy storage battery based on the electrical energy provided by the black-start bus (this could be achieved by a first isolation optocoupler in another battery pack transmitting the input energy to the output, thus transmitting the energy to the auxiliary power supply in an electrically isolated manner). For example, please refer again... Figure 2 , Figure 2 Battery pack 1 in the battery cluster can be the target battery pack, which includes a black start control (which can be a button) and an isolation winding. When the button in battery pack 1 is pressed and held for a period of time, the electrical connection between the auxiliary power supply and the energy storage battery in the battery pack can be established. The auxiliary power supply in battery pack 1 can supply power to the black start bus through the isolation winding based on the electrical energy provided by the energy storage battery. Here, since it is essentially supplying power for the process of establishing the electrical connection between the auxiliary power supply and the energy storage battery, rather than supplying power to the auxiliary power supply, the power required by the black start bus is very small, generally in the milliwatt range. Battery packs 2 to n in the battery cluster do not have black start controls. Electrical energy can be transmitted to battery packs 2 to n through the black start bus, so that the auxiliary power supply in battery packs 2 to n establishes the electrical connection with the energy storage battery based on the electrical energy provided by the black start bus (or the first isolation optocoupler in another battery pack can transmit the electrical energy from the input end to the output end, so as to transmit the electrical energy to the auxiliary power supply in an electrically isolated form). The auxiliary power supply in each battery pack can power the controller based on the electrical energy provided by the energy storage battery. The controller can control the first switching transistor in each battery pack (e.g., Figure 2 or Figure 3The switching transistor S1 in the battery pack is turned on to connect the energy storage battery in series to the battery cluster bus. The energy storage system triggers the black-start control in a single target battery pack, causing the target battery pack to draw power from the energy storage battery in that battery pack and supply power to the black-start bus. The black-start bus then supplies auxiliary power to other battery packs (to establish the electrical connection between the auxiliary power and the energy storage battery of other battery packs), avoiding the problems of poor startup experience, high cost, and low reliability caused by installing black-start controls in all battery packs within the battery cluster. In addition, the energy storage system uses auxiliary power to draw power from the energy storage battery to achieve black start, solving the problem that black start cannot be achieved based on cluster-level bus power supply when the battery cluster bus is de-energized, even when the battery pack has a built-in battery optimizer (which may include the first and second switching transistors). This makes it highly applicable.

[0030] In some feasible implementations, the battery pack may also include a voltage regulation unit and a second isolation optocoupler; please refer again to Figure 3 , Figure 3 The battery pack shown includes a first isolation optocoupler and a second isolation optocoupler. The secondary winding of the isolation winding in the battery pack can be connected to the black start bus via a voltage adjustment unit. The input terminal of the second isolation optocoupler is connected to a controller, and the output terminal of the second isolation optocoupler is connected to the voltage adjustment unit. The controller can send control commands to the voltage adjustment unit via the second isolation optocoupler to control the voltage adjustment unit to perform voltage transformation on the secondary winding voltage of the isolation winding to output a target voltage (which can be a safe voltage below 60V, such as 48V, 36V, 24V, 15V, 12V, etc.) to the black start bus. Here, the secondary winding voltage of the isolation winding can be the DC voltage obtained by voltage transformation from the output voltage of the isolation winding to the auxiliary power supply port (which can be the output voltage obtained based on the power supply from the energy storage battery). At the end of the black start, the controller can also send control commands to the voltage adjustment unit via the second isolation optocoupler to stop supplying power to the black start bus, preventing continuous power supply when black start is not needed and thus consuming the energy storage battery's power. The light-emitting diode in the second isolation optocoupler converts the input electrical energy into an optical signal, which is then transmitted to the phototube and converted into electrical energy output. This allows for power transmission between the black start bus and the battery pack without a direct electrical connection, preventing interference caused by an electrical connection between the black start bus and the battery pack, resulting in good power transmission performance.

[0031] In some feasible implementations, the primary winding of the isolation winding in the battery pack can be connected to an auxiliary power supply via a voltage regulation unit; please refer to [link to relevant documentation]. Figure 4 , Figure 4 This is another structural schematic diagram of the battery pack provided in this application, such as... Figure 4As shown, the primary winding of the isolation winding in the battery pack can be connected to an auxiliary power supply via a voltage adjustment unit. The controller in the battery pack is directly connected to the voltage adjustment unit. The controller can send control commands to the voltage adjustment unit to control the voltage adjustment unit to transform the output voltage of the auxiliary power supply port, so that the isolation winding further transforms the voltage output by the voltage adjustment unit. The secondary winding of the isolation winding outputs a target voltage (which can be a safe voltage below 60V, such as 48V, 36V, 24V, 15V, 12V, etc.) to the black start bus. The secondary winding of the isolation winding can be connected to the black start bus via a transformer circuit. This transformer circuit transforms the output voltage of the secondary winding of the isolation winding to output the target voltage to the black start bus. At the end of the black start, the controller can also send control commands to the voltage adjustment unit to stop supplying power to the black start bus, preventing continuous power supply when black start is not needed and thus consuming the battery power of the energy storage battery.

[0032] In some feasible implementations, the energy storage system may also include an uninterruptible power supply (UPS). The UPS is coupled to a black-start bus, which supplies power to the black-start bus, enabling the auxiliary power supply in the multiple series-connected battery packs to establish an electrical connection between the auxiliary power supply and the energy storage batteries. (This could be achieved by a first isolation optocoupler in the battery pack transferring power from the input to the output, thus providing electrical isolation to the auxiliary power supply.) Please refer to [further details to be added]. Figure 5 , Figure 5 This is another structural schematic diagram of the energy storage system provided in this application, such as... Figure 5As shown, the energy storage system may include a black-start bus 1 and a black-start bus 2, which are connected to battery cluster 1 and battery cluster 2, respectively. The UPS in the energy storage system is coupled to the aforementioned black-start bus 1 and black-start bus 2 through a voltage converter. Here, the aforementioned voltage converter can be a voltage converter with DC voltage conversion (for example, when the UPS can provide DC voltage), or it can be a DC voltage converter with rectification and DC voltage conversion (for example, when the UPS can provide AC voltage). It can be determined according to the specific device type and is not limited here. During the black start process, the UPS can supply power to the voltage converter, which transforms the voltage to output the target voltage to the black start bus 1 and black start bus 2. This allows black start bus 1 to supply power to battery packs 1 to m connected in series in battery cluster 1, and black start bus 2 to supply power to battery packs 1 to n connected in series in battery cluster 2. The first isolation optocoupler in each battery pack can transfer the power from the input end to the output end, thus transferring the power to the auxiliary power supply contained therein, thereby establishing the electrical connection between the auxiliary power supply and the energy storage battery. It is understandable that the UPS only needs to supply power to the black start bus for the process of establishing the electrical connection between the auxiliary power supply and the energy storage battery (equivalent to supplying power to the diodes of the first isolation optocouplers in each battery pack). Its supply current only needs to be a few milliamps. Therefore, even if there are hundreds of battery packs in the energy storage system, the UPS power is only at the level of tens or hundreds of watts, far lower than the scheme where the UPS directly supplies power to the individual boards in each battery pack. This reduces the UPS power capacity and significantly reduces the cost of black start.

[0033] In some feasible implementations, the energy storage system may further include a remote centralized controller and a local start-up controller. During black start-up, the remote centralized controller can communicate with the UPS and control the UPS to supply power (AC or DC) to the voltage converter. The remote centralized controller can send a black start-up command to the local start-up controller, causing the local start-up controller to communicate with the voltage converter and control the voltage converter to output a target voltage to its coupled black start-up bus (black start-up bus 1 and black start-up bus 2). This causes black start-up bus 1 to supply power to battery packs 1 to m connected in series in battery cluster 1, and black start-up bus 2 to supply power to battery packs 1 to n connected in series in battery cluster 2. The first isolation optocoupler in each battery pack can transfer the electrical energy from the input end to the output end, thereby transferring the electrical energy to the auxiliary power supply contained therein. After the auxiliary power supply in each battery pack starts up, the auxiliary power supply supplies power to the controller in each battery pack. The controller can control the first switching transistor in each battery pack (e.g., Figure 2 or Figure 3The switching transistor S1 in the battery pack is turned on to connect the energy storage battery in series to the battery cluster bus. Here, the black-start method of supplying power to the black-start bus via the UPS eliminates the process of triggering the black-start control (such as pressing a button), and the UPS only needs to supply power for the process of connecting the auxiliary power supply to the energy storage battery (equivalent to supplying power to the diode of the first isolation optocoupler in each battery pack). Its supply current is only a few milliamps. Therefore, even if there are hundreds of battery packs in the energy storage system, the power of the UPS is only at the level of tens or hundreds of watts, which is far lower than the scheme of the UPS directly supplying power to the single board in each battery pack. This reduces the power capacity of the UPS and achieves a significant reduction in black-start cost.

[0034] In this application, a target battery pack in multiple battery packs establishes an electrical connection between its target energy storage battery and a target auxiliary power supply via a black-start control. This allows the target auxiliary power supply to power the target controller and the black-start bus within the target battery pack based on the electrical energy provided by the target energy storage battery. This triggers the black-start bus to supply power to the auxiliary power supplies of the other battery packs in the multiple battery packs, excluding the target battery pack. The auxiliary power supplies of each of the other battery packs establish electrical connections with their respective energy storage batteries based on the electrical energy provided by the black-start bus, and supply power to the controllers of their respective battery packs based on the electrical energy provided by the energy storage batteries. By triggering the black-start control in a single target battery pack, the energy storage system causes the target battery pack to draw power from its energy storage battery and supply power to the black-start bus, which then supplies power to the auxiliary power supplies of other battery packs (establishing electrical connections between the auxiliary power supplies and energy storage batteries of other battery packs). This avoids the problems of poor startup experience, high cost, and low reliability caused by requiring black-start controls to be installed in all battery packs within a battery cluster. Furthermore, the energy storage system can also supply power to the aforementioned black-start bus via a UPS, enabling the black-start bus to supply power to the auxiliary power supplies in the multiple series-connected battery packs. This allows the auxiliary power supplies of each battery pack to establish electrical connections with the energy storage batteries within each battery pack based on the power supplied by the black-start bus (this can be achieved by the first isolation optocoupler in the battery pack transmitting the input power to the output power, thus providing electrical isolation to the auxiliary power supply). The UPS only needs to supply power to the black-start bus for the process of establishing electrical connections between the auxiliary power supply and the energy storage batteries (equivalent to supplying power to the diodes of the first isolation optocouplers in each battery pack), requiring only a few milliamps of current. Therefore, even if the energy storage system has hundreds of battery packs, the UPS power is only at the level of tens or hundreds of watts, far lower than the solution where the UPS directly supplies power to the individual boards in each battery pack, reducing the UPS power capacity and significantly lowering the cost of black-start operation.

Claims

1. An energy storage system, characterized in that, The energy storage system includes a battery cluster and a black start bus. The battery cluster is coupled to the AC grid. The battery cluster includes multiple battery packs connected in series. The battery pack includes an energy storage battery, a controller, and an auxiliary power supply connected in parallel with the energy storage battery. The auxiliary power supply is coupled to the black start bus. The plurality of battery packs includes a target battery pack associated with a black start control. The black start control is disposed between a target energy storage battery and a target auxiliary power supply in the target battery pack. The black start control is used to conduct the electrical connection between the target energy storage battery and the target auxiliary power supply when triggered. The target auxiliary power supply is used to supply power to the target controller and the black start bus in the target battery pack based on the electrical energy provided by the target energy storage battery, so as to trigger the black start bus to supply power to the auxiliary power supply of the other battery packs in the plurality of battery packs except the target battery pack. The auxiliary power supply of each battery pack in the other battery packs is used to make electrical connections with each energy storage battery of each battery pack based on the power provided by the black start bus, and to power the controller of each battery pack based on the power provided by each energy storage battery. The battery pack also includes an isolation power supply circuit, through which the auxiliary power supply is connected in parallel to the black start bus; the isolation power supply circuit is used to transmit electrical energy from the black start bus to the auxiliary power supply in an electrically isolated manner.

2. The energy storage system according to claim 1, characterized in that, The isolated power supply circuit includes a first isolation optocoupler, the input terminal of which is coupled to the black start bus, and the energy storage battery is connected to the start port of the auxiliary power supply through the output terminal of the first isolation optocoupler. The first isolation optocoupler is used to transmit electrical energy from the input terminal of the first isolation optocoupler to the output terminal of the first isolation optocoupler, so as to conduct the electrical connection between the energy storage battery and the start-up port of the auxiliary power supply.

3. The energy storage system according to claim 2, characterized in that, The output terminal of the first isolation optocoupler in the target battery pack is connected in parallel with the black start control between the start port of the target energy storage battery and the target auxiliary power supply in the target battery pack. The target isolation power supply circuit in the target battery pack also includes an isolation winding. The power supply port of the target auxiliary power supply is connected to the black start bus through the isolation winding. The target auxiliary power supply is used to draw power from the target energy storage battery and supply power to the black start bus through the isolation winding.

4. The energy storage system according to claim 3, characterized in that, The target isolated power supply circuit also includes a voltage adjustment unit, and the primary winding of the isolation winding is connected to the target auxiliary power supply through the voltage adjustment unit; The target controller in the target battery pack is used to control the voltage adjustment unit to perform voltage transformation on the output voltage of the target auxiliary power supply, so as to output the target voltage to the black start bus through the isolation winding.

5. The energy storage system according to claim 3, characterized in that, The target isolated power supply circuit also includes a voltage adjustment unit and a second isolation optocoupler. The secondary winding of the isolation winding is connected to the black start bus through the voltage adjustment unit. The input terminal of the second isolation optocoupler is connected to the target controller in the target battery pack, and the output terminal of the second isolation optocoupler is connected to the voltage adjustment unit. The target controller in the target battery pack is used to send control commands to the voltage adjustment unit through the second isolation optocoupler. The control commands are used to control the voltage adjustment unit to perform voltage transformation on the secondary winding voltage of the isolation winding so as to output the target voltage to the black start bus through the isolation winding.

6. The energy storage system according to any one of claims 1-5, characterized in that, The energy storage system also includes an uninterruptible power supply (UPS), which is coupled to the black start bus. The UPS is used to supply power to the black start bus and trigger the black start bus to supply power to the auxiliary power supply in the multiple battery packs.

7. The energy storage system according to any one of claims 1-6, characterized in that, Each of the plurality of battery packs further includes a first switching transistor and a second switching transistor. The first switching transistor is connected in series with the energy storage battery of each battery pack, and the second switching transistor is connected in parallel with the energy storage battery of each battery pack. The controller of each battery pack is used to control the first switching transistor of each battery pack to be turned on and the second switching transistor to be turned off, so as to connect the energy storage battery in each battery pack in series to the battery cluster bus.

8. A black-start device, characterized in that, The black start device is used in an energy storage system, which includes a battery cluster and a black start bus. The battery cluster includes multiple battery packs connected in series. Each battery pack includes an energy storage battery, a controller, and an auxiliary power supply connected in parallel with the energy storage battery. The auxiliary power supply is coupled to the black start bus. The black start device includes a black start control. When triggered, the black start control is used to connect the target energy storage battery of the target battery pack in the plurality of battery packs to the target auxiliary power supply. The target auxiliary power supply is used to supply power to the target controller in the target battery pack and the black start bus based on the power provided by the target energy storage battery, so as to trigger the black start bus to supply power to the auxiliary power supply of the other battery packs in the plurality of battery packs except the target battery pack. The black start device is used to connect to each energy storage battery of each battery pack through the auxiliary power supply of each battery pack in the other battery packs based on the power provided by the black start bus, and to power the controller of each battery pack based on the power provided by each energy storage battery. The black start device also includes an isolation power supply circuit, through which the auxiliary power supply is connected in parallel to the black start bus; the isolation power supply circuit is used to transmit electrical energy from the black start bus to the auxiliary power supply in an electrically isolated manner.

9. The black-start device according to claim 8, characterized in that, The isolated power supply circuit includes a first isolation optocoupler. The input terminal of the first isolation optocoupler is coupled to the black start bus. The energy storage battery is connected to the start port of the auxiliary power supply through the output terminal of the first isolation optocoupler. The first isolation optocoupler is used to transfer the electrical energy from the input terminal of the first isolation optocoupler to the output terminal of the first isolation optocoupler, so as to conduct the electrical connection between the energy storage battery and the start port of the auxiliary power supply.

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